[ltt-dev] [PP?] Re: Liblttd patch

Michael Sills-Lavoie michael.sills.lavoie at gmail.com
Sat Mar 27 13:49:46 EDT 2010


Le 2010-03-26 16:00, Mathieu Desnoyers a écrit :
> * Mathieu Desnoyers (compudj at krystal.dyndns.org) wrote:
>    
>> * Mathieu Desnoyers (compudj at krystal.dyndns.org) wrote:
>>      
>>> * Michael Sills Lavoie (michael.sills-lavoie at polymtl.ca) wrote:
>>>        
>>>> Hey,
>>>>
>>>> Here is the completed version of the new lttd and liblttd. We splitted the
>>>> work in 3 parts.
>>>>
>>>> 1) Move the code from lttd to liblttd and adapt everything so it works
>>>> 2) Adds the multiple instances feature
>>>> 3) Create utility methods in the library to support local write to disk
>>>>
>>>> We have done the last patch to make it possible for other programs to write
>>>> traces to disk without creating a new process (lttd). This way, we can share
>>>> the callbacks to write to the disk with other programs.
>>>>
>>>> What do you think about it?
>>>>          
>>> I am merging these patches, thanks ! (will also merge the following fix
>>> you sent).
>>>
>>> I will rename the "utility" library in a subsequent patch though, as
>>> "local" does not seem to be appropriate here. I propose to call that
>>> "vfswrite".
>>>        
>> finally I'll just use the "vfs" suffix.
>>
>> I will also change the liblttd* license to LGPLv2.1 (unless you have any
>> objection).
>>      
> It's now available in ltt-control 0.81. Please see commit
>
> 8ba26eaefd4104c2951d4a29bec7ddd2059bbeff
>
> for the cleanups and error handling fixes I added.
>
> Thanks,
>
> Mathieu
>    
Thanks for the merge.

I think you forgot to add the liblttdvfs.c/h files in the latest git 
commit (tag 0.81). Those files are present in the tar.gz on lttng.org. 
It causes the git version to ouput errors at compilation.

Michael
>    
>> Thanks,
>>
>> Mathieu
>>
>>      
>>> Thanks,
>>>
>>> Mathieu
>>>
>>>        
>>>> Thanks
>>>>
>>>> Michael and Oumarou
>>>>
>>>> 2010/2/16 Mathieu Desnoyers<compudj at krystal.dyndns.org>
>>>>
>>>>          
>>>>> * Michael Sills Lavoie (michael.sills-lavoie at polymtl.ca) wrote:
>>>>>            
>>>>>> Hey,
>>>>>>
>>>>>> This is a working implementation of the new liblttd and lttd. This is
>>>>>>              
>>>>> only a
>>>>>            
>>>>>> work in progress because we don't have the possibility to create multiple
>>>>>> instances of the "daemon" yet.
>>>>>>
>>>>>> You can apply the patch with : git apply liblttd.patch in the ltt-control
>>>>>> root directory.
>>>>>>
>>>>>> What do you think about it ?
>>>>>>              
>>>>>
>>>>> A few things: please take the habit of writing your comments in english
>>>>> so everyone on the mailing list can parse them ;)
>>>>>
>>>>> You should probably review the kernel doc coding styles for the function
>>>>> comments.
>>>>>
>>>>> Besides that, things seems to be generally on the right track.
>>>>>
>>>>> You should probably submit these changes in two patches:
>>>>>
>>>>> - first, just move the code from lttd to liblttd and adapt everything so
>>>>>   it works (more or less this patch).
>>>>> - second, a patch that adds the multiple instances feature.
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Mathieu
>>>>>
>>>>>            
>>>>>> Michael
>>>>>>              
>>>>>            
>>>>>> diff --git a/Makefile.am b/Makefile.am
>>>>>> index 8f9974d..06500fd 100644
>>>>>> --- a/Makefile.am
>>>>>> +++ b/Makefile.am
>>>>>> @@ -1,2 +1,2 @@
>>>>>> -SUBDIRS = liblttctl lttctl lttd specs
>>>>>> +SUBDIRS = liblttctl lttctl liblttd lttd specs
>>>>>>
>>>>>> diff --git a/configure.in b/configure.in
>>>>>> index d67e7d4..a992cd8 100644
>>>>>> --- a/configure.in
>>>>>> +++ b/configure.in
>>>>>> @@ -76,8 +76,10 @@ DEFAULT_INCLUDES="-I\$(top_srcdir) -I\$(top_builddir)"
>>>>>>   #AC_SUBST(CPPFLAGS)
>>>>>>
>>>>>>   lttctlincludedir="${includedir}/liblttctl"
>>>>>> +liblttdincludedir="${includedir}/liblttd"
>>>>>>
>>>>>>   AC_SUBST(lttctlincludedir)
>>>>>> +AC_SUBST(liblttdincludedir)
>>>>>>   AC_SUBST(UTIL_LIBS)
>>>>>>   AC_SUBST(THREAD_LIBS)
>>>>>>   AC_SUBST(DEFAULT_INCLUDES)
>>>>>> @@ -85,6 +87,7 @@ AC_SUBST(DEFAULT_INCLUDES)
>>>>>>   AC_CONFIG_FILES([Makefile
>>>>>>        liblttctl/Makefile
>>>>>>        lttctl/Makefile
>>>>>> +     liblttd/Makefile
>>>>>>        lttd/Makefile
>>>>>>        specs/Makefile])
>>>>>>   AC_OUTPUT
>>>>>> diff --git a/liblttd/Makefile.am b/liblttd/Makefile.am
>>>>>> new file mode 100644
>>>>>> index 0000000..3c1eeda
>>>>>> --- /dev/null
>>>>>> +++ b/liblttd/Makefile.am
>>>>>> @@ -0,0 +1,7 @@
>>>>>> +
>>>>>> +
>>>>>> +lib_LTLIBRARIES = liblttd.la
>>>>>> +liblttd_la_SOURCES = liblttd.c
>>>>>> +
>>>>>> +liblttdinclude_HEADERS = \
>>>>>> +     liblttd.h
>>>>>> diff --git a/liblttd/liblttd.c b/liblttd/liblttd.c
>>>>>> new file mode 100644
>>>>>> index 0000000..941ca87
>>>>>> --- /dev/null
>>>>>> +++ b/liblttd/liblttd.c
>>>>>> @@ -0,0 +1,754 @@
>>>>>> +/* lttd
>>>>>> + *
>>>>>> + * Linux Trace Toolkit Daemon
>>>>>> + *
>>>>>> + * This is a simple daemon that reads a few relay+debugfs channels and
>>>>>>              
>>>>> save
>>>>>            
>>>>>> + * them in a trace.
>>>>>> + *
>>>>>> + * CPU hot-plugging is supported using inotify.
>>>>>> + *
>>>>>> + * Copyright 2005 -
>>>>>> + *   Mathieu Desnoyers<mathieu.desnoyers at polymtl.ca>
>>>>>> + */
>>>>>> +
>>>>>> +#ifdef HAVE_CONFIG_H
>>>>>> +#include<config.h>
>>>>>> +#endif
>>>>>> +
>>>>>> +#include "liblttd.h"
>>>>>> +
>>>>>> +#define _REENTRANT
>>>>>> +#define _GNU_SOURCE
>>>>>> +#include<features.h>
>>>>>> +#include<stdio.h>
>>>>>> +#include<unistd.h>
>>>>>> +#include<errno.h>
>>>>>> +#include<sys/types.h>
>>>>>> +#include<stdlib.h>
>>>>>> +#include<dirent.h>
>>>>>> +#include<string.h>
>>>>>> +#include<fcntl.h>
>>>>>> +#include<sys/stat.h>
>>>>>> +#include<sys/poll.h>
>>>>>> +#include<sys/mman.h>
>>>>>> +#include<sys/syscall.h>
>>>>>> +#include<unistd.h>
>>>>>> +#include<asm/ioctls.h>
>>>>>> +
>>>>>> +#include<linux/version.h>
>>>>>> +
>>>>>> +/* Relayfs IOCTL */
>>>>>> +#include<asm/ioctl.h>
>>>>>> +#include<asm/types.h>
>>>>>> +
>>>>>> +/* Get the next sub buffer that can be read. */
>>>>>> +#define RELAY_GET_SB         _IOR(0xF5, 0x00,__u32)
>>>>>> +/* Release the oldest reserved (by "get") sub buffer. */
>>>>>> +#define RELAY_PUT_SB         _IOW(0xF5, 0x01,__u32)
>>>>>> +/* returns the number of sub buffers in the per cpu channel. */
>>>>>> +#define RELAY_GET_N_SB               _IOR(0xF5, 0x02,__u32)
>>>>>> +/* returns the size of the current sub buffer. */
>>>>>> +#define RELAY_GET_SB_SIZE    _IOR(0xF5, 0x03, __u32)
>>>>>> +/* returns the size of data to consume in the current sub-buffer. */
>>>>>> +#define RELAY_GET_MAX_SB_SIZE        _IOR(0xF5, 0x04, __u32)
>>>>>> +
>>>>>> +
>>>>>> +#if LINUX_VERSION_CODE>= KERNEL_VERSION(2,6,14)
>>>>>> +#include<sys/inotify.h>
>>>>>> +
>>>>>> +#define HAS_INOTIFY
>>>>>> +#else
>>>>>> +static inline int inotify_init (void)
>>>>>> +{
>>>>>> +     return -1;
>>>>>> +}
>>>>>> +
>>>>>> +static inline int inotify_add_watch (int fd, const char *name, __u32
>>>>>>              
>>>>> mask)
>>>>>            
>>>>>> +{
>>>>>> +     return 0;
>>>>>> +}
>>>>>> +
>>>>>> +static inline int inotify_rm_watch (int fd, __u32 wd)
>>>>>> +{
>>>>>> +     return 0;
>>>>>> +}
>>>>>> +#undef HAS_INOTIFY
>>>>>> +#endif
>>>>>> +
>>>>>> +/* !modif! Enlever, seulement utilisé pendant l'implémentation*/
>>>>>> +struct liblttd_callbacks *callbacks;
>>>>>> +
>>>>>> +struct channel_trace_fd {
>>>>>> +     struct fd_pair *pair;
>>>>>> +     int num_pairs;
>>>>>> +};
>>>>>> +
>>>>>> +/* !modif! Modifier pour pas utiliser le chemin de la trace*/
>>>>>> +struct inotify_watch {
>>>>>> +     int wd;
>>>>>> +     char path_channel[PATH_MAX];
>>>>>> +     char *base_path_channel;
>>>>>> +};
>>>>>> +
>>>>>> +struct inotify_watch_array {
>>>>>> +     struct inotify_watch *elem;
>>>>>> +     int num;
>>>>>> +};
>>>>>> +
>>>>>> +struct channel_trace_fd fd_pairs = { NULL, 0 };
>>>>>> +int inotify_fd = -1;
>>>>>> +struct inotify_watch_array inotify_watch_array = { NULL, 0 };
>>>>>> +
>>>>>> +/* protects fd_pairs and inotify_watch_array */
>>>>>> +pthread_rwlock_t fd_pairs_lock = PTHREAD_RWLOCK_INITIALIZER;
>>>>>> +
>>>>>> +/* !modif! Mettre dans une structure s'il faut avoir plus d'une
>>>>>>              
>>>>> instance*/
>>>>>            
>>>>>> +static char          *channel_name = NULL;
>>>>>> +static unsigned long num_threads = 1;
>>>>>> +volatile static int  quit_program = 0;       /* For signal handler */
>>>>>> +static int           dump_flight_only = 0;
>>>>>> +static int           dump_normal_only = 0;
>>>>>> +static int           verbose_mode = 0;
>>>>>> +
>>>>>> +#define printf_verbose(fmt, args...) \
>>>>>> +  do {                               \
>>>>>> +    if (verbose_mode)                \
>>>>>> +      printf(fmt, ##args);           \
>>>>>> +  } while (0)
>>>>>> +
>>>>>> +
>>>>>> +int open_buffer_file(char *filename, char *path_channel,
>>>>>> +     char *base_path_channel, struct channel_trace_fd *fd_pairs)
>>>>>> +{
>>>>>> +     int open_ret = 0;
>>>>>> +     int ret = 0;
>>>>>> +
>>>>>> +     if(strncmp(filename, "flight-", sizeof("flight-")-1) != 0) {
>>>>>> +             if(dump_flight_only) {
>>>>>> +                     printf_verbose("Skipping normal channel %s\n",
>>>>>> +                             path_channel);
>>>>>> +                     return 0;
>>>>>> +             }
>>>>>> +     } else {
>>>>>> +             if(dump_normal_only) {
>>>>>> +                     printf_verbose("Skipping flight channel %s\n",
>>>>>> +                             path_channel);
>>>>>> +                     return 0;
>>>>>> +             }
>>>>>> +     }
>>>>>> +     printf_verbose("Opening file.\n");
>>>>>> +
>>>>>> +     fd_pairs->pair = realloc(fd_pairs->pair,
>>>>>> +                     ++fd_pairs->num_pairs * sizeof(struct fd_pair));
>>>>>> +
>>>>>> +     /* Open the channel in read mode */
>>>>>> +     fd_pairs->pair[fd_pairs->num_pairs-1].channel =
>>>>>> +             open(path_channel, O_RDONLY | O_NONBLOCK);
>>>>>> +     if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) {
>>>>>> +             perror(path_channel);
>>>>>> +             fd_pairs->num_pairs--;
>>>>>> +             return 0;       /* continue */
>>>>>> +     }
>>>>>> +
>>>>>> +     /*!callback! Ajouter un callback pour l'ouverture.*/
>>>>>> +     if(callbacks->on_open_channel) ret = callbacks->on_open_channel(
>>>>>> +                     callbacks,&fd_pairs->pair[fd_pairs->num_pairs-1],
>>>>>> +                     base_path_channel);
>>>>>> +
>>>>>> +     if(ret != 0) {
>>>>>> +             open_ret = -1;
>>>>>> +             close(fd_pairs->pair[fd_pairs->num_pairs-1].channel);
>>>>>> +             fd_pairs->num_pairs--;
>>>>>> +             goto end;
>>>>>> +     }
>>>>>> +
>>>>>> +end:
>>>>>> +     return open_ret;
>>>>>> +}
>>>>>> +
>>>>>> +int open_channel_trace_pairs(char *subchannel_name,
>>>>>> +             char *base_subchannel_name,
>>>>>> +             struct channel_trace_fd *fd_pairs, int *inotify_fd,
>>>>>> +             struct inotify_watch_array *iwatch_array)
>>>>>> +{
>>>>>> +     DIR *channel_dir = opendir(subchannel_name);
>>>>>> +     struct dirent *entry;
>>>>>> +     struct stat stat_buf;
>>>>>> +     int ret;
>>>>>> +     char path_channel[PATH_MAX];
>>>>>> +     int path_channel_len;
>>>>>> +     char *path_channel_ptr;
>>>>>> +     char *base_subchannel_ptr;
>>>>>> +
>>>>>> +     int open_ret = 0;
>>>>>> +
>>>>>> +     if(channel_dir == NULL) {
>>>>>> +             perror(subchannel_name);
>>>>>> +             open_ret = ENOENT;
>>>>>> +             goto end;
>>>>>> +     }
>>>>>> +
>>>>>> +     printf_verbose("Calling on new channels folder");
>>>>>> +     if(callbacks->on_new_channels_folder) ret = callbacks->
>>>>>> +                     on_new_channels_folder(callbacks,
>>>>>> +                     base_subchannel_name);
>>>>>> +     if(ret == -1) {
>>>>>> +             open_ret = -1;
>>>>>> +             goto end;
>>>>>> +     }
>>>>>> +
>>>>>> +     strncpy(path_channel, subchannel_name, PATH_MAX-1);
>>>>>> +     path_channel_len = strlen(path_channel);
>>>>>> +     path_channel[path_channel_len] = '/';
>>>>>> +     path_channel_len++;
>>>>>> +     path_channel_ptr = path_channel + path_channel_len;
>>>>>> +     base_subchannel_ptr = path_channel +
>>>>>> +             (base_subchannel_name - subchannel_name);
>>>>>> +
>>>>>> +#ifdef HAS_INOTIFY
>>>>>> +     iwatch_array->elem = realloc(iwatch_array->elem,
>>>>>> +             ++iwatch_array->num * sizeof(struct inotify_watch));
>>>>>> +
>>>>>> +     printf_verbose("Adding inotify for channel %s\n", path_channel);
>>>>>> +     iwatch_array->elem[iwatch_array->num-1].wd =
>>>>>>              
>>>>> inotify_add_watch(*inotify_fd, path_channel, IN_CREATE);
>>>>>            
>>>>>> +     strcpy(iwatch_array->elem[iwatch_array->num-1].path_channel,
>>>>>>              
>>>>> path_channel);
>>>>>            
>>>>>> +     iwatch_array->elem[iwatch_array->num-1].base_path_channel =
>>>>>> +             iwatch_array->elem[iwatch_array->num-1].path_channel +
>>>>>> +             (base_subchannel_name - subchannel_name);
>>>>>> +     printf_verbose("Added inotify for channel %s, wd %u\n",
>>>>>> +             iwatch_array->elem[iwatch_array->num-1].path_channel,
>>>>>> +             iwatch_array->elem[iwatch_array->num-1].wd);
>>>>>> +#endif
>>>>>> +
>>>>>> +     while((entry = readdir(channel_dir)) != NULL) {
>>>>>> +
>>>>>> +             if(entry->d_name[0] == '.') continue;
>>>>>> +
>>>>>> +             strncpy(path_channel_ptr, entry->d_name, PATH_MAX -
>>>>>>              
>>>>> path_channel_len);
>>>>>            
>>>>>> +
>>>>>> +             ret = stat(path_channel,&stat_buf);
>>>>>> +             if(ret == -1) {
>>>>>> +                     perror(path_channel);
>>>>>> +                     continue;
>>>>>> +             }
>>>>>> +
>>>>>> +             printf_verbose("Channel file : %s\n", path_channel);
>>>>>> +
>>>>>> +             if(S_ISDIR(stat_buf.st_mode)) {
>>>>>> +
>>>>>> +                     printf_verbose("Entering channel
>>>>>>              
>>>>> subdirectory...\n");
>>>>>            
>>>>>> +                     ret = open_channel_trace_pairs(path_channel,
>>>>>>              
>>>>> base_subchannel_ptr, fd_pairs,
>>>>>            
>>>>>> +                             inotify_fd, iwatch_array);
>>>>>> +                     if(ret<  0) continue;
>>>>>> +             } else if(S_ISREG(stat_buf.st_mode)) {
>>>>>> +                     open_ret = open_buffer_file(entry->d_name,
>>>>>>              
>>>>> path_channel, base_subchannel_ptr,
>>>>>            
>>>>>> +                             fd_pairs);
>>>>>> +                     if(open_ret)
>>>>>> +                             goto end;
>>>>>> +             }
>>>>>> +     }
>>>>>> +
>>>>>> +end:
>>>>>> +     closedir(channel_dir);
>>>>>> +
>>>>>> +     return open_ret;
>>>>>> +}
>>>>>> +
>>>>>> +
>>>>>> +int read_subbuffer(struct fd_pair *pair)
>>>>>> +{
>>>>>> +     unsigned int consumed_old, len;
>>>>>> +     int err;
>>>>>> +     long ret;
>>>>>> +     off_t offset;
>>>>>> +
>>>>>> +
>>>>>> +     err = ioctl(pair->channel, RELAY_GET_SB,&consumed_old);
>>>>>> +     printf_verbose("cookie : %u\n", consumed_old);
>>>>>> +     if(err != 0) {
>>>>>> +             ret = errno;
>>>>>> +             perror("Reserving sub buffer failed (everything is normal,
>>>>>>              
>>>>> it is due to concurrency)");
>>>>>            
>>>>>> +             goto get_error;
>>>>>> +     }
>>>>>> +
>>>>>> +     err = ioctl(pair->channel, RELAY_GET_SB_SIZE,&len);
>>>>>> +     if(err != 0) {
>>>>>> +             ret = errno;
>>>>>> +             perror("Getting sub-buffer len failed.");
>>>>>> +             goto get_error;
>>>>>> +     }
>>>>>> +
>>>>>> +     if(callbacks->on_read_subbuffer) ret =
>>>>>>              
>>>>> callbacks->on_read_subbuffer(
>>>>>            
>>>>>> +             callbacks, pair, len);
>>>>>> +
>>>>>> +write_error:
>>>>>> +     ret = 0;
>>>>>> +     err = ioctl(pair->channel, RELAY_PUT_SB,&consumed_old);
>>>>>> +     if(err != 0) {
>>>>>> +             ret = errno;
>>>>>> +             if(errno == EFAULT) {
>>>>>> +                     perror("Error in unreserving sub buffer\n");
>>>>>> +             } else if(errno == EIO) {
>>>>>> +                     /* Should never happen with newer LTTng versions */
>>>>>> +                     perror("Reader has been pushed by the writer, last
>>>>>>              
>>>>> sub-buffer corrupted.");
>>>>>            
>>>>>> +             }
>>>>>> +             goto get_error;
>>>>>> +     }
>>>>>> +
>>>>>> +get_error:
>>>>>> +     return ret;
>>>>>> +}
>>>>>> +
>>>>>> +
>>>>>> +int map_channels(struct channel_trace_fd *fd_pairs,
>>>>>> +     int idx_begin, int idx_end)
>>>>>> +{
>>>>>> +     int i,j;
>>>>>> +     int ret=0;
>>>>>> +
>>>>>> +     if(fd_pairs->num_pairs<= 0) {
>>>>>> +             printf("No channel to read\n");
>>>>>> +             goto end;
>>>>>> +     }
>>>>>> +
>>>>>> +     /* Get the subbuf sizes and number */
>>>>>> +
>>>>>> +     for(i=idx_begin;i<idx_end;i++) {
>>>>>> +             struct fd_pair *pair =&fd_pairs->pair[i];
>>>>>> +
>>>>>> +             ret = ioctl(pair->channel, RELAY_GET_N_SB,&pair->n_sb);
>>>>>> +             if(ret != 0) {
>>>>>> +                     perror("Error in getting the number of
>>>>>>              
>>>>> sub-buffers");
>>>>>            
>>>>>> +                     goto end;
>>>>>> +             }
>>>>>> +             ret = ioctl(pair->channel, RELAY_GET_MAX_SB_SIZE,
>>>>>> +&pair->max_sb_size);
>>>>>> +             if(ret != 0) {
>>>>>> +                     perror("Error in getting the max sub-buffer size");
>>>>>> +                     goto end;
>>>>>> +             }
>>>>>> +             ret = pthread_mutex_init(&pair->mutex, NULL);   /* Fast
>>>>>>              
>>>>> mutex */
>>>>>            
>>>>>> +             if(ret != 0) {
>>>>>> +                     perror("Error in mutex init");
>>>>>> +                     goto end;
>>>>>> +             }
>>>>>> +     }
>>>>>> +
>>>>>> +end:
>>>>>> +     return ret;
>>>>>> +}
>>>>>> +
>>>>>> +int unmap_channels(struct channel_trace_fd *fd_pairs)
>>>>>> +{
>>>>>> +     int j;
>>>>>> +     int ret=0;
>>>>>> +
>>>>>> +     /* Munmap each FD */
>>>>>> +     for(j=0;j<fd_pairs->num_pairs;j++) {
>>>>>> +             struct fd_pair *pair =&fd_pairs->pair[j];
>>>>>> +             int err_ret;
>>>>>> +
>>>>>> +             err_ret = pthread_mutex_destroy(&pair->mutex);
>>>>>> +             if(err_ret != 0) {
>>>>>> +                     perror("Error in mutex destroy");
>>>>>> +             }
>>>>>> +             ret |= err_ret;
>>>>>> +     }
>>>>>> +
>>>>>> +     return ret;
>>>>>> +}
>>>>>> +
>>>>>> +#ifdef HAS_INOTIFY
>>>>>> +/* Inotify event arrived.
>>>>>> + *
>>>>>> + * Only support add file for now.
>>>>>> + */
>>>>>> +
>>>>>> +int read_inotify(int inotify_fd,
>>>>>> +     struct channel_trace_fd *fd_pairs,
>>>>>> +     struct inotify_watch_array *iwatch_array)
>>>>>> +{
>>>>>> +     char buf[sizeof(struct inotify_event) + PATH_MAX];
>>>>>> +     char path_channel[PATH_MAX];
>>>>>> +     ssize_t len;
>>>>>> +     struct inotify_event *ievent;
>>>>>> +     size_t offset;
>>>>>> +     unsigned int i;
>>>>>> +     int ret;
>>>>>> +     int old_num;
>>>>>> +
>>>>>> +     offset = 0;
>>>>>> +     len = read(inotify_fd, buf, sizeof(struct inotify_event) +
>>>>>>              
>>>>> PATH_MAX);
>>>>>            
>>>>>> +     if(len<  0) {
>>>>>> +
>>>>>> +             if(errno == EAGAIN)
>>>>>> +                     return 0;  /* another thread got the data before us
>>>>>>              
>>>>> */
>>>>>            
>>>>>> +
>>>>>> +             printf("Error in read from inotify FD %s.\n",
>>>>>>              
>>>>> strerror(len));
>>>>>            
>>>>>> +             return -1;
>>>>>> +     }
>>>>>> +     while(offset<  len) {
>>>>>> +             ievent = (struct inotify_event *)&(buf[offset]);
>>>>>> +             for(i=0; i<iwatch_array->num; i++) {
>>>>>> +                     if(iwatch_array->elem[i].wd == ievent->wd&&
>>>>>> +                             ievent->mask == IN_CREATE) {
>>>>>> +                             printf_verbose(
>>>>>> +                                     "inotify wd %u event mask : %u for
>>>>>>              
>>>>> %s%s\n",
>>>>>            
>>>>>> +                                     ievent->wd, ievent->mask,
>>>>>> +                                     iwatch_array->elem[i].path_channel,
>>>>>> +                                     ievent->name);
>>>>>> +                             old_num = fd_pairs->num_pairs;
>>>>>> +                             strcpy(path_channel,
>>>>>>              
>>>>> iwatch_array->elem[i].path_channel);
>>>>>            
>>>>>> +                             strcat(path_channel, ievent->name);
>>>>>> +                             if(ret = open_buffer_file(ievent->name,
>>>>>>              
>>>>> path_channel,
>>>>>            
>>>>>> +                                     path_channel +
>>>>>>              
>>>>> (iwatch_array->elem[i].base_path_channel -
>>>>>            
>>>>>> +
>>>>>>              
>>>>> iwatch_array->elem[i].path_channel), fd_pairs)) {
>>>>>            
>>>>>> +                                     printf("Error opening buffer
>>>>>>              
>>>>> file\n");
>>>>>            
>>>>>> +                                     return -1;
>>>>>> +                             }
>>>>>> +                             if(ret = map_channels(fd_pairs, old_num,
>>>>>>              
>>>>> fd_pairs->num_pairs)) {
>>>>>            
>>>>>> +                                     printf("Error mapping channel\n");
>>>>>> +                                     return -1;
>>>>>> +                             }
>>>>>> +
>>>>>> +                     }
>>>>>> +             }
>>>>>> +             offset += sizeof(*ievent) + ievent->len;
>>>>>> +     }
>>>>>> +}
>>>>>> +#endif //HAS_INOTIFY
>>>>>> +
>>>>>> +/* read_channels
>>>>>> + *
>>>>>> + * Thread worker.
>>>>>> + *
>>>>>> + * Read the debugfs channels and write them in the paired tracefiles.
>>>>>> + *
>>>>>> + * @fd_pairs : paired channels and trace files.
>>>>>> + *
>>>>>> + * returns 0 on success, -1 on error.
>>>>>> + *
>>>>>> + * Note that the high priority polled channels are consumed first. We
>>>>>>              
>>>>> then poll
>>>>>            
>>>>>> + * again to see if these channels are still in priority. Only when no
>>>>>> + * high priority channel is left, we start reading low priority
>>>>>>              
>>>>> channels.
>>>>>            
>>>>>> + *
>>>>>> + * Note that a channel is considered high priority when the buffer is
>>>>>>              
>>>>> almost
>>>>>            
>>>>>> + * full.
>>>>>> + */
>>>>>> +
>>>>>> +int read_channels(unsigned long thread_num, struct channel_trace_fd
>>>>>>              
>>>>> *fd_pairs,
>>>>>            
>>>>>> +     int inotify_fd, struct inotify_watch_array *iwatch_array)
>>>>>> +{
>>>>>> +     struct pollfd *pollfd = NULL;
>>>>>> +     int num_pollfd;
>>>>>> +     int i,j;
>>>>>> +     int num_rdy, num_hup;
>>>>>> +     int high_prio;
>>>>>> +     int ret = 0;
>>>>>> +     int inotify_fds;
>>>>>> +     unsigned int old_num;
>>>>>> +
>>>>>> +#ifdef HAS_INOTIFY
>>>>>> +     inotify_fds = 1;
>>>>>> +#else
>>>>>> +     inotify_fds = 0;
>>>>>> +#endif
>>>>>> +
>>>>>> +     pthread_rwlock_rdlock(&fd_pairs_lock);
>>>>>> +
>>>>>> +     /* Start polling the FD. Keep one fd for inotify */
>>>>>> +     pollfd = malloc((inotify_fds + fd_pairs->num_pairs) * sizeof(struct
>>>>>>              
>>>>> pollfd));
>>>>>            
>>>>>> +
>>>>>> +#ifdef HAS_INOTIFY
>>>>>> +     pollfd[0].fd = inotify_fd;
>>>>>> +     pollfd[0].events = POLLIN|POLLPRI;
>>>>>> +#endif
>>>>>> +
>>>>>> +     for(i=0;i<fd_pairs->num_pairs;i++) {
>>>>>> +             pollfd[inotify_fds+i].fd = fd_pairs->pair[i].channel;
>>>>>> +             pollfd[inotify_fds+i].events = POLLIN|POLLPRI;
>>>>>> +     }
>>>>>> +     num_pollfd = inotify_fds + fd_pairs->num_pairs;
>>>>>> +
>>>>>> +
>>>>>> +     pthread_rwlock_unlock(&fd_pairs_lock);
>>>>>> +
>>>>>> +     while(1) {
>>>>>> +             high_prio = 0;
>>>>>> +             num_hup = 0;
>>>>>> +#ifdef DEBUG
>>>>>> +             printf("Press a key for next poll...\n");
>>>>>> +             char buf[1];
>>>>>> +             read(STDIN_FILENO,&buf, 1);
>>>>>> +             printf("Next poll (polling %d fd) :\n", num_pollfd);
>>>>>> +#endif //DEBUG
>>>>>> +
>>>>>> +             /* Have we received a signal ? */
>>>>>> +             if(quit_program) break;
>>>>>> +
>>>>>> +             num_rdy = poll(pollfd, num_pollfd, -1);
>>>>>> +
>>>>>> +             if(num_rdy == -1) {
>>>>>> +                     perror("Poll error");
>>>>>> +                     goto free_fd;
>>>>>> +             }
>>>>>> +
>>>>>> +             printf_verbose("Data received\n");
>>>>>> +#ifdef HAS_INOTIFY
>>>>>> +             switch(pollfd[0].revents) {
>>>>>> +                     case POLLERR:
>>>>>> +                             printf_verbose(
>>>>>> +                                     "Error returned in polling inotify
>>>>>>              
>>>>> fd %d.\n",
>>>>>            
>>>>>> +                                     pollfd[0].fd);
>>>>>> +                             break;
>>>>>> +                     case POLLHUP:
>>>>>> +                             printf_verbose(
>>>>>> +                                     "Polling inotify fd %d tells it has
>>>>>>              
>>>>> hung up.\n",
>>>>>            
>>>>>> +                                     pollfd[0].fd);
>>>>>> +                             break;
>>>>>> +                     case POLLNVAL:
>>>>>> +                             printf_verbose(
>>>>>> +                                     "Polling inotify fd %d tells fd is
>>>>>>              
>>>>> not open.\n",
>>>>>            
>>>>>> +                                     pollfd[0].fd);
>>>>>> +                             break;
>>>>>> +                     case POLLPRI:
>>>>>> +                     case POLLIN:
>>>>>> +                             printf_verbose(
>>>>>> +                                     "Polling inotify fd %d : data
>>>>>>              
>>>>> ready.\n",
>>>>>            
>>>>>> +                                     pollfd[0].fd);
>>>>>> +
>>>>>> +                             pthread_rwlock_wrlock(&fd_pairs_lock);
>>>>>> +                             read_inotify(inotify_fd, fd_pairs,
>>>>>>              
>>>>> iwatch_array);
>>>>>            
>>>>>> +                             pthread_rwlock_unlock(&fd_pairs_lock);
>>>>>> +
>>>>>> +                     break;
>>>>>> +             }
>>>>>> +#endif
>>>>>> +
>>>>>> +             for(i=inotify_fds;i<num_pollfd;i++) {
>>>>>> +                     switch(pollfd[i].revents) {
>>>>>> +                             case POLLERR:
>>>>>> +                                     printf_verbose(
>>>>>> +                                             "Error returned in polling
>>>>>>              
>>>>> fd %d.\n",
>>>>>            
>>>>>> +                                             pollfd[i].fd);
>>>>>> +                                     num_hup++;
>>>>>> +                                     break;
>>>>>> +                             case POLLHUP:
>>>>>> +                                     printf_verbose(
>>>>>> +                                             "Polling fd %d tells it has
>>>>>>              
>>>>> hung up.\n",
>>>>>            
>>>>>> +                                             pollfd[i].fd);
>>>>>> +                                     num_hup++;
>>>>>> +                                     break;
>>>>>> +                             case POLLNVAL:
>>>>>> +                                     printf_verbose(
>>>>>> +                                             "Polling fd %d tells fd is
>>>>>>              
>>>>> not open.\n",
>>>>>            
>>>>>> +                                             pollfd[i].fd);
>>>>>> +                                     num_hup++;
>>>>>> +                                     break;
>>>>>> +                             case POLLPRI:
>>>>>> +
>>>>>>              
>>>>> pthread_rwlock_rdlock(&fd_pairs_lock);
>>>>>            
>>>>>> +
>>>>>>              
>>>>> if(pthread_mutex_trylock(&fd_pairs->pair[i-inotify_fds].mutex) == 0) {
>>>>>            
>>>>>> +                                             printf_verbose(
>>>>>> +                                                     "Urgent read on fd
>>>>>>              
>>>>> %d\n",
>>>>>            
>>>>>> +                                                     pollfd[i].fd);
>>>>>> +                                             /* Take care of high
>>>>>>              
>>>>> priority channels first. */
>>>>>            
>>>>>> +                                             high_prio = 1;
>>>>>> +                                             /* it's ok to have an
>>>>>>              
>>>>> unavailable sub-buffer */
>>>>>            
>>>>>> +                                             ret =
>>>>>>              
>>>>> read_subbuffer(&fd_pairs->pair[i-inotify_fds]);
>>>>>            
>>>>>> +                                             if(ret == EAGAIN) ret = 0;
>>>>>> +
>>>>>> +                                             ret =
>>>>>>              
>>>>> pthread_mutex_unlock(&fd_pairs->pair[i-inotify_fds].mutex);
>>>>>            
>>>>>> +                                             if(ret)
>>>>>> +                                                     printf("Error in
>>>>>>              
>>>>> mutex unlock : %s\n", strerror(ret));
>>>>>            
>>>>>> +                                     }
>>>>>> +
>>>>>>              
>>>>> pthread_rwlock_unlock(&fd_pairs_lock);
>>>>>            
>>>>>> +                                     break;
>>>>>> +                     }
>>>>>> +             }
>>>>>> +             /* If every buffer FD has hung up, we end the read loop
>>>>>>              
>>>>> here */
>>>>>            
>>>>>> +             if(num_hup == num_pollfd - inotify_fds) break;
>>>>>> +
>>>>>> +             if(!high_prio) {
>>>>>> +                     for(i=inotify_fds;i<num_pollfd;i++) {
>>>>>> +                             switch(pollfd[i].revents) {
>>>>>> +                                     case POLLIN:
>>>>>> +
>>>>>>              
>>>>> pthread_rwlock_rdlock(&fd_pairs_lock);
>>>>>            
>>>>>> +
>>>>>>              
>>>>> if(pthread_mutex_trylock(&fd_pairs->pair[i-inotify_fds].mutex) == 0) {
>>>>>            
>>>>>> +                                                     /* Take care of low
>>>>>>              
>>>>> priority channels. */
>>>>>            
>>>>>> +                                                     printf_verbose(
>>>>>> +                                                             "Normal
>>>>>>              
>>>>> read on fd %d\n",
>>>>>            
>>>>>> +
>>>>>>              
>>>>> pollfd[i].fd);
>>>>>            
>>>>>> +                                                     /* it's ok to have
>>>>>>              
>>>>> an unavailable subbuffer */
>>>>>            
>>>>>> +                                                     ret =
>>>>>>              
>>>>> read_subbuffer(&fd_pairs->pair[i-inotify_fds]);
>>>>>            
>>>>>> +                                                     if(ret == EAGAIN)
>>>>>>              
>>>>> ret = 0;
>>>>>            
>>>>>> +
>>>>>> +                                                     ret =
>>>>>>              
>>>>> pthread_mutex_unlock(&fd_pairs->pair[i-inotify_fds].mutex);
>>>>>            
>>>>>> +                                                     if(ret)
>>>>>> +
>>>>>>              
>>>>> printf("Error in mutex unlock : %s\n", strerror(ret));
>>>>>            
>>>>>> +                                             }
>>>>>> +
>>>>>>              
>>>>> pthread_rwlock_unlock(&fd_pairs_lock);
>>>>>            
>>>>>> +                                             break;
>>>>>> +                             }
>>>>>> +                     }
>>>>>> +             }
>>>>>> +
>>>>>> +             /* Update pollfd array if an entry was added to fd_pairs */
>>>>>> +             pthread_rwlock_rdlock(&fd_pairs_lock);
>>>>>> +             if((inotify_fds + fd_pairs->num_pairs) != num_pollfd) {
>>>>>> +                     pollfd = realloc(pollfd,
>>>>>> +                                     (inotify_fds + fd_pairs->num_pairs)
>>>>>>              
>>>>> * sizeof(struct pollfd));
>>>>>            
>>>>>> +
>>>>>>              
>>>>> for(i=num_pollfd-inotify_fds;i<fd_pairs->num_pairs;i++) {
>>>>>            
>>>>>> +                             pollfd[inotify_fds+i].fd =
>>>>>>              
>>>>> fd_pairs->pair[i].channel;
>>>>>            
>>>>>> +                             pollfd[inotify_fds+i].events =
>>>>>>              
>>>>> POLLIN|POLLPRI;
>>>>>            
>>>>>> +                     }
>>>>>> +                     num_pollfd = fd_pairs->num_pairs + inotify_fds;
>>>>>> +             }
>>>>>> +             pthread_rwlock_unlock(&fd_pairs_lock);
>>>>>> +
>>>>>> +             /* NB: If the fd_pairs structure is updated by another
>>>>>>              
>>>>> thread from this
>>>>>            
>>>>>> +              *     point forward, the current thread will wait in the
>>>>>>              
>>>>> poll without
>>>>>            
>>>>>> +              *     monitoring the new channel. However, this thread
>>>>>>              
>>>>> will add the
>>>>>            
>>>>>> +              *     new channel on next poll (and this should not take
>>>>>>              
>>>>> too much time
>>>>>            
>>>>>> +              *     on a loaded system).
>>>>>> +              *
>>>>>> +              *     This event is quite unlikely and can only occur if a
>>>>>>              
>>>>> CPU is
>>>>>            
>>>>>> +              *     hot-plugged while multple lttd threads are running.
>>>>>> +              */
>>>>>> +     }
>>>>>> +
>>>>>> +free_fd:
>>>>>> +     free(pollfd);
>>>>>> +
>>>>>> +end:
>>>>>> +     return ret;
>>>>>> +}
>>>>>> +
>>>>>> +
>>>>>> +void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs, int
>>>>>>              
>>>>> inotify_fd,
>>>>>            
>>>>>> +     struct inotify_watch_array *iwatch_array)
>>>>>> +{
>>>>>> +     int i;
>>>>>> +     int ret;
>>>>>> +
>>>>>> +     for(i=0;i<fd_pairs->num_pairs;i++) {
>>>>>> +             ret = close(fd_pairs->pair[i].channel);
>>>>>> +             if(ret == -1) perror("Close error on channel");
>>>>>> +             if(callbacks->on_close_channel) {
>>>>>> +                     ret = callbacks->on_close_channel(
>>>>>> +                             callbacks,&fd_pairs->pair[i]);
>>>>>> +                     if(ret != 0) perror("Error on close channel
>>>>>>              
>>>>> callback");
>>>>>            
>>>>>> +             }
>>>>>> +     }
>>>>>> +     free(fd_pairs->pair);
>>>>>> +     free(iwatch_array->elem);
>>>>>> +}
>>>>>> +
>>>>>> +/* Thread worker */
>>>>>> +void * thread_main(void *arg)
>>>>>> +{
>>>>>> +     long ret = 0;
>>>>>> +     unsigned long thread_num = (unsigned long)arg;
>>>>>> +
>>>>>> +     if(callbacks->on_new_thread)
>>>>>> +             ret = callbacks->on_new_thread(callbacks, thread_num);
>>>>>> +
>>>>>> +     if (ret<  0) {
>>>>>> +             return (void*)ret;
>>>>>> +     }
>>>>>> +     ret = read_channels(thread_num,&fd_pairs, inotify_fd,
>>>>>>              
>>>>> &inotify_watch_array);
>>>>>            
>>>>>> +
>>>>>> +     if(callbacks->on_close_thread)
>>>>>> +             callbacks->on_close_thread(callbacks, thread_num);
>>>>>> +
>>>>>> +     return (void*)ret;
>>>>>> +}
>>>>>> +
>>>>>> +/*on_close_thread has to be reentrant, it'll be called by many threads*/
>>>>>> +int(*on_close_thread)(struct liblttd_callbacks *data, unsigned long
>>>>>>              
>>>>> thread_num);
>>>>>            
>>>>>> +
>>>>>> +int channels_init()
>>>>>> +{
>>>>>> +     int ret = 0;
>>>>>> +
>>>>>> +     inotify_fd = inotify_init();
>>>>>> +     fcntl(inotify_fd, F_SETFL, O_NONBLOCK);
>>>>>> +
>>>>>> +     if(ret = open_channel_trace_pairs(channel_name,
>>>>>> +                     channel_name + strlen(channel_name),&fd_pairs,
>>>>>> +&inotify_fd,&inotify_watch_array))
>>>>>> +             goto close_channel;
>>>>>> +     if (fd_pairs.num_pairs == 0) {
>>>>>> +             printf("No channel available for reading, exiting\n");
>>>>>> +             ret = -ENOENT;
>>>>>> +             goto close_channel;
>>>>>> +     }
>>>>>> +     if(ret = map_channels(&fd_pairs, 0, fd_pairs.num_pairs))
>>>>>> +             goto close_channel;
>>>>>> +     return 0;
>>>>>> +
>>>>>> +close_channel:
>>>>>> +     close_channel_trace_pairs(&fd_pairs, inotify_fd,
>>>>>>              
>>>>> &inotify_watch_array);
>>>>>            
>>>>>> +     if(inotify_fd>= 0)
>>>>>> +             close(inotify_fd);
>>>>>> +     return ret;
>>>>>> +}
>>>>>> +
>>>>>> +int liblttd_start(char *channel_path, unsigned long n_threads,
>>>>>> +             int flight_only, int normal_only, int verbose,
>>>>>> +             struct liblttd_callbacks *user_data){
>>>>>> +     int ret = 0;
>>>>>> +     pthread_t *tids;
>>>>>> +     unsigned long i;
>>>>>> +     void *tret;
>>>>>> +
>>>>>> +     /*!modif! C'est seulement la pour tester, on devrait tester pour
>>>>>>              
>>>>> voir si
>>>>>            
>>>>>> +     les arguments sont valide. On fera surement ca autrement avec
>>>>>>              
>>>>> plusieurs
>>>>>            
>>>>>> +     instances*/
>>>>>> +     channel_name = channel_path;
>>>>>> +     num_threads = n_threads;
>>>>>> +     dump_flight_only = flight_only;
>>>>>> +     dump_normal_only = normal_only;
>>>>>> +     verbose_mode = verbose;
>>>>>> +     callbacks = user_data;
>>>>>> +
>>>>>> +     if(ret = channels_init())
>>>>>> +             return ret;
>>>>>> +
>>>>>> +     tids = malloc(sizeof(pthread_t) * num_threads);
>>>>>> +     for(i=0; i<num_threads; i++) {
>>>>>> +
>>>>>> +             ret = pthread_create(&tids[i], NULL, thread_main,
>>>>>>              
>>>>> (void*)i);
>>>>>            
>>>>>> +             if(ret) {
>>>>>> +                     perror("Error creating thread");
>>>>>> +                     break;
>>>>>> +             }
>>>>>> +     }
>>>>>> +
>>>>>> +     for(i=0; i<num_threads; i++) {
>>>>>> +             ret = pthread_join(tids[i],&tret);
>>>>>> +             if(ret) {
>>>>>> +                     perror("Error joining thread");
>>>>>> +                     break;
>>>>>> +             }
>>>>>> +             if((long)tret != 0) {
>>>>>> +                     printf("Error %s occured in thread %ld\n",
>>>>>> +                             strerror((long)tret), i);
>>>>>> +             }
>>>>>> +     }
>>>>>> +
>>>>>> +     free(tids);
>>>>>> +     ret = unmap_channels(&fd_pairs);
>>>>>> +     close_channel_trace_pairs(&fd_pairs, inotify_fd,
>>>>>>              
>>>>> &inotify_watch_array);
>>>>>            
>>>>>> +     if(inotify_fd>= 0)
>>>>>> +             close(inotify_fd);
>>>>>> +
>>>>>> +     if(callbacks->on_trace_end) callbacks->on_trace_end(callbacks);
>>>>>> +
>>>>>> +     return ret;
>>>>>> +}
>>>>>> +
>>>>>> +int liblttd_stop() {
>>>>>> +     quit_program = 1;
>>>>>> +     return 0;
>>>>>> +}
>>>>>> +
>>>>>> diff --git a/liblttd/liblttd.h b/liblttd/liblttd.h
>>>>>> new file mode 100644
>>>>>> index 0000000..bd76eeb
>>>>>> --- /dev/null
>>>>>> +++ b/liblttd/liblttd.h
>>>>>> @@ -0,0 +1,218 @@
>>>>>> +/* liblttd header file
>>>>>> + *
>>>>>> + * Copyright 2010-
>>>>>> + *            Oumarou Dicko<oumarou.dicko at polymtl.ca>
>>>>>> + *            Michael Sills-Lavoie<michael.sills-lavoie at polymtl.ca>
>>>>>> + *
>>>>>> + *
>>>>>> + * This program is free software; you can redistribute it and/or modify
>>>>>> + * it under the terms of the GNU General Public License as published by
>>>>>> + * the Free Software Foundation; either version 2 of the License, or
>>>>>> + * (at your option) any later version.
>>>>>> + *
>>>>>> + * This program is distributed in the hope that it will be useful,
>>>>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>>>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.      See the
>>>>>> + * GNU General Public License for more details.
>>>>>> + *
>>>>>> + */
>>>>>> +
>>>>>> +#ifndef _LIBLTTD_H
>>>>>> +#define _LIBLTTD_H
>>>>>> +
>>>>>> +#include<pthread.h>
>>>>>> +
>>>>>> +/**
>>>>>> +* This structure contains the data associated with the channel file
>>>>>>              
>>>>> descriptor.
>>>>>            
>>>>>> +* The lib user can use user_data to store the data associated to the
>>>>>>              
>>>>> specified
>>>>>            
>>>>>> +* channel. The lib user can read but MUST NOT change the other
>>>>>>              
>>>>> attributes.
>>>>>            
>>>>>> +*/
>>>>>> +struct fd_pair {
>>>>>> +     /**
>>>>>> +     * This is the channel file descriptor.
>>>>>> +     */
>>>>>> +     int channel;
>>>>>> +
>>>>>> +     /**
>>>>>> +     * This is the number of subbuffer for this channel.
>>>>>> +     */
>>>>>> +     unsigned int n_sb;
>>>>>> +
>>>>>> +     /**
>>>>>> +     * This is the subbuffer size for this channel.
>>>>>> +     */
>>>>>> +     unsigned int max_sb_size;
>>>>>> +
>>>>>> +     /**
>>>>>> +     * Not used anymore.
>>>>>> +     */
>>>>>> +     void *mmap;
>>>>>> +
>>>>>> +     /**
>>>>>> +     * This is a mutex for internal library usage.
>>>>>> +     */
>>>>>> +     pthread_mutex_t mutex;
>>>>>> +
>>>>>> +     /**
>>>>>> +     * Library user data.
>>>>>> +     */
>>>>>> +     void *user_data;
>>>>>> +};
>>>>>> +
>>>>>> +/**
>>>>>> +* This structure contains the necessary callbacks for a tracing session.
>>>>>>              
>>>>> The
>>>>>            
>>>>>> +* user can set the unnecessary functions to NULL if he does not need
>>>>>>              
>>>>> them.
>>>>>            
>>>>>> +*/
>>>>>> +struct liblttd_callbacks {
>>>>>> +     /**
>>>>>> +     * This callback is called after a channel file is open.
>>>>>> +     *
>>>>>> +     * @args data This argument is a pointeur to the callbacks struct
>>>>>>              
>>>>> that
>>>>>            
>>>>>> +     *            has been passed to the lib.
>>>>>> +     * @args pair This structure contains the data associated with the
>>>>>> +     *            channel file descriptor. The lib user can use
>>>>>>              
>>>>> user_data to
>>>>>            
>>>>>> +     *            store the data associated to the specified channel.
>>>>>> +     * @args relative_channel_path This argument represents a relative
>>>>>>              
>>>>> path
>>>>>            
>>>>>> +     *            to the channel file. This path is relative to the root
>>>>>> +     *            folder of the trace channels.
>>>>>> +     *
>>>>>> +     * @return Should return 0 if the callback succeeds else not 0.
>>>>>> +     */
>>>>>> +     int(*on_open_channel)(struct liblttd_callbacks *data,
>>>>>> +             struct fd_pair *pair, char *relative_channel_path);
>>>>>> +
>>>>>> +     /**
>>>>>> +     * This callback is called after a channel file is closed.
>>>>>> +     *
>>>>>> +     * @remarks After a channel file has been closed, it will never be
>>>>>>              
>>>>> read
>>>>>            
>>>>>> +     *            again.
>>>>>> +     *
>>>>>> +     * @args data This argument is a pointeur to the callbacks struct
>>>>>>              
>>>>> that
>>>>>            
>>>>>> +     *            has been passed to the lib.
>>>>>> +     * @args pair This structure contains the data associated with the
>>>>>> +     *            channel file descriptor. The lib user should clean
>>>>>> +     *            user_data at this time.
>>>>>> +     *
>>>>>> +     * @return Should return 0 if the callback succeeds else not 0.
>>>>>> +     */
>>>>>> +     int(*on_close_channel)(struct liblttd_callbacks *data,
>>>>>> +             struct fd_pair *pair);
>>>>>> +
>>>>>> +
>>>>>> +     /**
>>>>>> +     * This callback is called when the library enter in a new subfolder
>>>>>> +     * while it is scanning the trace channel tree. It can be used to
>>>>>>              
>>>>> create
>>>>>            
>>>>>> +     * the output file structure of the trace.
>>>>>> +     *
>>>>>> +     * @args data This argument is a pointeur to the callbacks struct
>>>>>>              
>>>>> that
>>>>>            
>>>>>> +     *            has been passed to the lib.
>>>>>> +     * @args relative_folder_path This argument represents a relative
>>>>>>              
>>>>> path
>>>>>            
>>>>>> +     *            to the channel folder. This path is relative to the
>>>>>>              
>>>>> root
>>>>>            
>>>>>> +     *            folder of the trace channels.
>>>>>> +     *
>>>>>> +     * @return Should return 0 if the callback succeeds else not 0.
>>>>>> +     */
>>>>>> +     int(*on_new_channels_folder)(struct liblttd_callbacks *data,
>>>>>> +             char *relative_folder_path);
>>>>>> +
>>>>>> +     /**
>>>>>> +     * This callback is called after a subbuffer is a reserved.
>>>>>> +     *
>>>>>> +     * @attention It has to be thread safe, it'll be called by many
>>>>>>              
>>>>> threads.
>>>>>            
>>>>>> +     *
>>>>>> +     * @args data This argument is a pointeur to the callbacks struct
>>>>>>              
>>>>> that
>>>>>            
>>>>>> +     *            has been passed to the lib.
>>>>>> +     * @args pair This structure contains the data associated with the
>>>>>> +     *            channel file descriptor. The lib user should clean
>>>>>> +     *            user_data at this time.
>>>>>> +     * @args len This argument represents the length the data that has
>>>>>>              
>>>>> to be
>>>>>            
>>>>>> +     *            read.
>>>>>> +     *
>>>>>> +     * @return Should return 0 if the callback succeeds else not 0.
>>>>>> +     */
>>>>>> +     int(*on_read_subbuffer)(struct liblttd_callbacks *data,
>>>>>> +             struct fd_pair *pair, unsigned int len);
>>>>>> +
>>>>>> +     /**
>>>>>> +     * This callback is called at the very end of the tracing session.
>>>>>>              
>>>>> At
>>>>>            
>>>>>> +     * this time, all the channels have been closed and the threads have
>>>>>>              
>>>>> been
>>>>>            
>>>>>> +     * destroyed.
>>>>>> +     *
>>>>>> +     * @remarks After this callback is called, no other callback will be
>>>>>> +     *            called again.
>>>>>> +     *
>>>>>> +     * @attention It has to be thread safe, it'll be called by many
>>>>>>              
>>>>> threads.
>>>>>            
>>>>>> +     *
>>>>>> +     * @args data This argument is a pointeur to the callbacks struct
>>>>>>              
>>>>> that
>>>>>            
>>>>>> +     *            has been passed to the lib.
>>>>>> +     *
>>>>>> +     * @return Should return 0 if the callback succeeds else not 0.
>>>>>> +     */
>>>>>> +     int(*on_trace_end)(struct liblttd_callbacks *data);
>>>>>> +
>>>>>> +     /**
>>>>>> +     * This callback is called after a new thread has been created.
>>>>>> +     *
>>>>>> +     * @attention It has to be thread safe, it'll be called by many
>>>>>>              
>>>>> threads.
>>>>>            
>>>>>> +     *
>>>>>> +     * @args data This argument is a pointeur to the callbacks struct
>>>>>>              
>>>>> that
>>>>>            
>>>>>> +     *            has been passed to the lib.
>>>>>> +     * @args thread_num This argument represents the id of the thread.
>>>>>> +     *
>>>>>> +     * @return Should return 0 if the callback succeeds else not 0.
>>>>>> +     */
>>>>>> +     int(*on_new_thread)(struct liblttd_callbacks *data,
>>>>>> +             unsigned long thread_num);
>>>>>> +
>>>>>> +     /**
>>>>>> +     * This callback is called just before a thread is destroyed.
>>>>>> +     *
>>>>>> +     * @attention It has to be thread safe, it'll be called by many
>>>>>>              
>>>>> threads.
>>>>>            
>>>>>> +     *
>>>>>> +     * @args data This argument is a pointeur to the callbacks struct
>>>>>>              
>>>>> that
>>>>>            
>>>>>> +     *            has been passed to the lib.
>>>>>> +     * @args thread_num This argument represents the number of the
>>>>>>              
>>>>> thread.
>>>>>            
>>>>>> +     *
>>>>>> +     * @return Should return 0 if the callback succeeds else not 0.
>>>>>> +     */
>>>>>> +     int(*on_close_thread)(struct liblttd_callbacks *data,
>>>>>> +             unsigned long thread_num);
>>>>>> +
>>>>>> +     /**
>>>>>> +     * This is where the user can put the library's data.
>>>>>> +     */
>>>>>> +     void *user_data;
>>>>>> +};
>>>>>> +
>>>>>> +/**
>>>>>> +* This function is called to start a new tracing session.
>>>>>> +*
>>>>>> +* @attention It has to be thread safe, it'll be called by many threads.
>>>>>> +*
>>>>>> +* @args channel_path This argument is a path to the root folder of the
>>>>>>              
>>>>> trace's
>>>>>            
>>>>>> +*            channels.
>>>>>> +* @args n_threads This argument represents the number of threads that
>>>>>>              
>>>>> will be
>>>>>            
>>>>>> +*            used by the library.
>>>>>> +* @args flight_only If this argument to set to 1, only the channel that
>>>>>>              
>>>>> are in
>>>>>            
>>>>>> +*            flight recorder mode will be recorded.
>>>>>> +* @args normal_only If this argument to set to 1, only the channel that
>>>>>>              
>>>>> are in
>>>>>            
>>>>>> +*            normal mode will be recorded.
>>>>>> +* @args verbose If this argument to set to 1, more informations will be
>>>>>>              
>>>>> printed.
>>>>>            
>>>>>> +* @args user_data This argument is a pointeur to the callbacks struct
>>>>>>              
>>>>> that
>>>>>            
>>>>>> +*            contains the user's functions.
>>>>>> +*
>>>>>> +* @return Return 0 if the function succeeds else not 0.
>>>>>> +*/
>>>>>> +int liblttd_start(char *channel_path, unsigned long n_threads,
>>>>>> +     int flight_only, int normal_only, int verbose,
>>>>>> +     struct liblttd_callbacks *user_data);
>>>>>> +
>>>>>> +/**
>>>>>> +* This function is called to stop a tracing session.
>>>>>> +*
>>>>>> +* @return Return 0 if the function succeeds.
>>>>>> +*/
>>>>>> +int liblttd_stop();
>>>>>> +
>>>>>> +#endif /*_LIBLTTD_H */
>>>>>> +
>>>>>> diff --git a/lttd/Makefile.am b/lttd/Makefile.am
>>>>>> index bb860bc..fc9b219 100644
>>>>>> --- a/lttd/Makefile.am
>>>>>> +++ b/lttd/Makefile.am
>>>>>> @@ -6,3 +6,6 @@ bin_PROGRAMS = lttd
>>>>>>
>>>>>>   lttd_SOURCES = lttd.c
>>>>>>
>>>>>> +lttd_DEPENDENCIES = ../liblttd/liblttd.la
>>>>>> +lttd_LDADD = $(lttd_DEPENDENCIES)
>>>>>> +
>>>>>> diff --git a/lttd/lttd.c b/lttd/lttd.c
>>>>>> index 773cb23..9143ef7 100644
>>>>>> --- a/lttd/lttd.c
>>>>>> +++ b/lttd/lttd.c
>>>>>> @@ -17,125 +17,36 @@
>>>>>>
>>>>>>   #define _REENTRANT
>>>>>>   #define _GNU_SOURCE
>>>>>> -#include<features.h>
>>>>>> +
>>>>>>   #include<stdio.h>
>>>>>> -#include<unistd.h>
>>>>>> -#include<errno.h>
>>>>>> -#include<sys/types.h>
>>>>>> -#include<sys/stat.h>
>>>>>>   #include<stdlib.h>
>>>>>> -#include<dirent.h>
>>>>>>   #include<string.h>
>>>>>> -#include<fcntl.h>
>>>>>> -#include<sys/poll.h>
>>>>>> -#include<sys/mman.h>
>>>>>>   #include<signal.h>
>>>>>> -#include<pthread.h>
>>>>>> -#include<sys/syscall.h>
>>>>>> -#include<unistd.h>
>>>>>> -#include<asm/ioctls.h>
>>>>>> -
>>>>>> -#include<linux/version.h>
>>>>>> -
>>>>>> -/* Relayfs IOCTL */
>>>>>> -#include<asm/ioctl.h>
>>>>>> -#include<asm/types.h>
>>>>>> -
>>>>>> -/* Get the next sub buffer that can be read. */
>>>>>> -#define RELAY_GET_SB         _IOR(0xF5, 0x00,__u32)
>>>>>> -/* Release the oldest reserved (by "get") sub buffer. */
>>>>>> -#define RELAY_PUT_SB         _IOW(0xF5, 0x01,__u32)
>>>>>> -/* returns the number of sub buffers in the per cpu channel. */
>>>>>> -#define RELAY_GET_N_SB               _IOR(0xF5, 0x02,__u32)
>>>>>> -/* returns the size of the current sub buffer. */
>>>>>> -#define RELAY_GET_SB_SIZE    _IOR(0xF5, 0x03, __u32)
>>>>>> -/* returns the size of data to consume in the current sub-buffer. */
>>>>>> -#define RELAY_GET_MAX_SB_SIZE        _IOR(0xF5, 0x04, __u32)
>>>>>> -
>>>>>> -
>>>>>> -#if LINUX_VERSION_CODE>= KERNEL_VERSION(2,6,14)
>>>>>> -#include<sys/inotify.h>
>>>>>> -#if 0        /* should now be provided by libc. */
>>>>>> -/* From the inotify-tools 2.6 package */
>>>>>> -static inline int inotify_init (void)
>>>>>> -{
>>>>>> -     return syscall (__NR_inotify_init);
>>>>>> -}
>>>>>> -
>>>>>> -static inline int inotify_add_watch (int fd, const char *name, __u32
>>>>>>              
>>>>> mask)
>>>>>            
>>>>>> -{
>>>>>> -     return syscall (__NR_inotify_add_watch, fd, name, mask);
>>>>>> -}
>>>>>> -
>>>>>> -static inline int inotify_rm_watch (int fd, __u32 wd)
>>>>>> -{
>>>>>> -     return syscall (__NR_inotify_rm_watch, fd, wd);
>>>>>> -}
>>>>>> -#endif //0
>>>>>> -#define HAS_INOTIFY
>>>>>> -#else
>>>>>> -static inline int inotify_init (void)
>>>>>> -{
>>>>>> -     return -1;
>>>>>> -}
>>>>>> +#include<errno.h>
>>>>>> +#include<fcntl.h>
>>>>>> +#include<dirent.h>
>>>>>> +#include<sys/stat.h>
>>>>>>
>>>>>> -static inline int inotify_add_watch (int fd, const char *name, __u32
>>>>>>              
>>>>> mask)
>>>>>            
>>>>>> -{
>>>>>> -     return 0;
>>>>>> -}
>>>>>> +#include<liblttd/liblttd.h>
>>>>>>
>>>>>> -static inline int inotify_rm_watch (int fd, __u32 wd)
>>>>>> -{
>>>>>> -     return 0;
>>>>>> -}
>>>>>> -#undef HAS_INOTIFY
>>>>>> -#endif
>>>>>> -
>>>>>> -struct fd_pair {
>>>>>> -     int channel;
>>>>>> +struct lttd_channel_data {
>>>>>>        int trace;
>>>>>> -     unsigned int n_sb;
>>>>>> -     unsigned int max_sb_size;
>>>>>> -     void *mmap;
>>>>>> -     pthread_mutex_t mutex;
>>>>>> -};
>>>>>> -
>>>>>> -struct channel_trace_fd {
>>>>>> -     struct fd_pair *pair;
>>>>>> -     int num_pairs;
>>>>>> -};
>>>>>> -
>>>>>> -struct inotify_watch {
>>>>>> -     int wd;
>>>>>> -     char path_channel[PATH_MAX];
>>>>>> -     char path_trace[PATH_MAX];
>>>>>> -};
>>>>>> -
>>>>>> -struct inotify_watch_array {
>>>>>> -     struct inotify_watch *elem;
>>>>>> -     int num;
>>>>>>   };
>>>>>>
>>>>>> -static __thread int thread_pipe[2];
>>>>>> -
>>>>>> -struct channel_trace_fd fd_pairs = { NULL, 0 };
>>>>>> -int inotify_fd = -1;
>>>>>> -struct inotify_watch_array inotify_watch_array = { NULL, 0 };
>>>>>> -
>>>>>> -/* protects fd_pairs and inotify_watch_array */
>>>>>> -pthread_rwlock_t fd_pairs_lock = PTHREAD_RWLOCK_INITIALIZER;
>>>>>> -
>>>>>> -
>>>>>> +static char          path_trace[PATH_MAX];
>>>>>> +static char          *end_path_trace;
>>>>>> +static int           path_trace_len = 0;
>>>>>>   static char          *trace_name = NULL;
>>>>>>   static char          *channel_name = NULL;
>>>>>>   static int           daemon_mode = 0;
>>>>>>   static int           append_mode = 0;
>>>>>>   static unsigned long num_threads = 1;
>>>>>> -volatile static int  quit_program = 0;       /* For signal handler */
>>>>>>   static int           dump_flight_only = 0;
>>>>>>   static int           dump_normal_only = 0;
>>>>>>   static int           verbose_mode = 0;
>>>>>>
>>>>>> +static __thread int thread_pipe[2];
>>>>>> +
>>>>>>   #define printf_verbose(fmt, args...) \
>>>>>>     do {                               \
>>>>>>       if (verbose_mode)                \
>>>>>> @@ -178,7 +89,7 @@ int parse_arguments(int argc, char **argv)
>>>>>>   {
>>>>>>        int ret = 0;
>>>>>>        int argn = 1;
>>>>>> -
>>>>>> +
>>>>>>        if(argc == 2) {
>>>>>>                if(strcmp(argv[1], "-h") == 0) {
>>>>>>                        return 1;
>>>>>> @@ -236,19 +147,19 @@ int parse_arguments(int argc, char **argv)
>>>>>>                }
>>>>>>                argn++;
>>>>>>        }
>>>>>> -
>>>>>> +
>>>>>>        if(trace_name == NULL) {
>>>>>>                printf("Please specify a trace name.\n");
>>>>>>                printf("\n");
>>>>>>                ret = -1;
>>>>>>        }
>>>>>> -
>>>>>> +
>>>>>>        if(channel_name == NULL) {
>>>>>>                printf("Please specify a channel name.\n");
>>>>>>                printf("\n");
>>>>>>                ret = -1;
>>>>>>        }
>>>>>> -
>>>>>> +
>>>>>>        return ret;
>>>>>>   }
>>>>>>
>>>>>> @@ -267,223 +178,96 @@ void show_info(void)
>>>>>>   static void handler(int signo)
>>>>>>   {
>>>>>>        printf("Signal %d received : exiting cleanly\n", signo);
>>>>>> -     quit_program = 1;
>>>>>> +     liblttd_stop();
>>>>>>   }
>>>>>>
>>>>>> -
>>>>>> -int open_buffer_file(char *filename, char *path_channel, char
>>>>>>              
>>>>> *path_trace,
>>>>>            
>>>>>> -     struct channel_trace_fd *fd_pairs)
>>>>>> +int lttd_on_open_channel(struct liblttd_callbacks *data, struct fd_pair
>>>>>>              
>>>>> *pair, char *relative_channel_path)
>>>>>            
>>>>>>   {
>>>>>>        int open_ret = 0;
>>>>>> -     int ret = 0;
>>>>>> +     int ret;
>>>>>>        struct stat stat_buf;
>>>>>> +     struct lttd_channel_data *channel_data;
>>>>>>
>>>>>> -     if(strncmp(filename, "flight-", sizeof("flight-")-1) != 0) {
>>>>>> -             if(dump_flight_only) {
>>>>>> -                     printf_verbose("Skipping normal channel %s\n",
>>>>>> -                             path_channel);
>>>>>> -                     return 0;
>>>>>> -             }
>>>>>> -     } else {
>>>>>> -             if(dump_normal_only) {
>>>>>> -                     printf_verbose("Skipping flight channel %s\n",
>>>>>> -                             path_channel);
>>>>>> -                     return 0;
>>>>>> -             }
>>>>>> -     }
>>>>>> -     printf_verbose("Opening file.\n");
>>>>>> -
>>>>>> -     fd_pairs->pair = realloc(fd_pairs->pair,
>>>>>> -                     ++fd_pairs->num_pairs * sizeof(struct fd_pair));
>>>>>> +     pair->user_data = malloc(sizeof(struct lttd_channel_data));
>>>>>> +     channel_data = pair->user_data;
>>>>>> +
>>>>>> +     strncpy(end_path_trace, relative_channel_path, PATH_MAX -
>>>>>>              
>>>>> path_trace_len);
>>>>>            
>>>>>> +     printf_verbose("Creating trace file %s\n", path_trace);
>>>>>>
>>>>>> -     /* Open the channel in read mode */
>>>>>> -     fd_pairs->pair[fd_pairs->num_pairs-1].channel =
>>>>>> -             open(path_channel, O_RDONLY | O_NONBLOCK);
>>>>>> -     if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) {
>>>>>> -             perror(path_channel);
>>>>>> -             fd_pairs->num_pairs--;
>>>>>> -             return 0;       /* continue */
>>>>>> -     }
>>>>>> -     /* Open the trace in write mode, only append if append_mode */
>>>>>>        ret = stat(path_trace,&stat_buf);
>>>>>>        if(ret == 0) {
>>>>>>                if(append_mode) {
>>>>>>                        printf_verbose("Appending to file %s as
>>>>>>              
>>>>> requested\n",
>>>>>            
>>>>>>                                path_trace);
>>>>>>
>>>>>> -                     fd_pairs->pair[fd_pairs->num_pairs-1].trace =
>>>>>> -                             open(path_trace, O_WRONLY,
>>>>>> -                                             S_IRWXU|S_IRWXG|S_IRWXO);
>>>>>> -                     if(fd_pairs->pair[fd_pairs->num_pairs-1].trace ==
>>>>>>              
>>>>> -1) {
>>>>>            
>>>>>> +                     channel_data->trace = open(path_trace, O_WRONLY,
>>>>>>              
>>>>> S_IRWXU|S_IRWXG|S_IRWXO);
>>>>>            
>>>>>> +                     if(channel_data->trace == -1) {
>>>>>>                                perror(path_trace);
>>>>>>                                open_ret = -1;
>>>>>> -
>>>>>>              
>>>>> close(fd_pairs->pair[fd_pairs->num_pairs-1].channel);
>>>>>            
>>>>>> -                             fd_pairs->num_pairs--;
>>>>>>                                goto end;
>>>>>>                        }
>>>>>> -                     ret =
>>>>>>              
>>>>> lseek(fd_pairs->pair[fd_pairs->num_pairs-1].trace,
>>>>>            
>>>>>> -                                 0, SEEK_END);
>>>>>> +                     ret = lseek(channel_data->trace, 0, SEEK_END);
>>>>>>                        if (ret<  0) {
>>>>>>                                perror(path_trace);
>>>>>>                                open_ret = -1;
>>>>>> -
>>>>>>              
>>>>> close(fd_pairs->pair[fd_pairs->num_pairs-1].channel);
>>>>>            
>>>>>> -
>>>>>>              
>>>>> close(fd_pairs->pair[fd_pairs->num_pairs-1].trace);
>>>>>            
>>>>>> -                             fd_pairs->num_pairs--;
>>>>>> +                             close(channel_data->trace);
>>>>>>                                goto end;
>>>>>>                        }
>>>>>>                } else {
>>>>>>                        printf("File %s exists, cannot open. Try append
>>>>>>              
>>>>> mode.\n", path_trace);
>>>>>            
>>>>>>                        open_ret = -1;
>>>>>> -
>>>>>>              
>>>>> close(fd_pairs->pair[fd_pairs->num_pairs-1].channel);
>>>>>            
>>>>>> -                     fd_pairs->num_pairs--;
>>>>>>                        goto end;
>>>>>>                }
>>>>>>        } else {
>>>>>>                if(errno == ENOENT) {
>>>>>> -                     fd_pairs->pair[fd_pairs->num_pairs-1].trace =
>>>>>> -                             open(path_trace, O_WRONLY|O_CREAT|O_EXCL,
>>>>>> -                                             S_IRWXU|S_IRWXG|S_IRWXO);
>>>>>> -                     if(fd_pairs->pair[fd_pairs->num_pairs-1].trace ==
>>>>>>              
>>>>> -1) {
>>>>>            
>>>>>> +                     channel_data->trace = open(path_trace,
>>>>>>              
>>>>> O_WRONLY|O_CREAT|O_EXCL, S_IRWXU|S_IRWXG|S_IRWXO);
>>>>>            
>>>>>> +                     if(channel_data->trace == -1) {
>>>>>>                                perror(path_trace);
>>>>>>                                open_ret = -1;
>>>>>> -
>>>>>>              
>>>>> close(fd_pairs->pair[fd_pairs->num_pairs-1].channel);
>>>>>            
>>>>>> -                             fd_pairs->num_pairs--;
>>>>>>                                goto end;
>>>>>>                        }
>>>>>>                }
>>>>>>        }
>>>>>> +
>>>>>>   end:
>>>>>>        return open_ret;
>>>>>> +
>>>>>>   }
>>>>>>
>>>>>> -int open_channel_trace_pairs(char *subchannel_name, char *subtrace_name,
>>>>>> -             struct channel_trace_fd *fd_pairs, int *inotify_fd,
>>>>>> -             struct inotify_watch_array *iwatch_array)
>>>>>> +int lttd_on_close_channel(struct liblttd_callbacks *data, struct fd_pair
>>>>>>              
>>>>> *pair)
>>>>>            
>>>>>> +{
>>>>>> +     int ret;
>>>>>> +     ret = close(((struct lttd_channel_data
>>>>>>              
>>>>> *)(pair->user_data))->trace);
>>>>>            
>>>>>> +     free(pair->user_data);
>>>>>> +     return ret;
>>>>>> +}
>>>>>> +
>>>>>> +int lttd_on_new_channels_folder(struct liblttd_callbacks *data, char
>>>>>>              
>>>>> *relative_folder_path)
>>>>>            
>>>>>>   {
>>>>>> -     DIR *channel_dir = opendir(subchannel_name);
>>>>>> -     struct dirent *entry;
>>>>>> -     struct stat stat_buf;
>>>>>>        int ret;
>>>>>> -     char path_channel[PATH_MAX];
>>>>>> -     int path_channel_len;
>>>>>> -     char *path_channel_ptr;
>>>>>> -     char path_trace[PATH_MAX];
>>>>>> -     int path_trace_len;
>>>>>> -     char *path_trace_ptr;
>>>>>>        int open_ret = 0;
>>>>>>
>>>>>> -     if(channel_dir == NULL) {
>>>>>> -             perror(subchannel_name);
>>>>>> -             open_ret = ENOENT;
>>>>>> -             goto end;
>>>>>> -     }
>>>>>> +     strncpy(end_path_trace, relative_folder_path, PATH_MAX -
>>>>>>              
>>>>> path_trace_len);
>>>>>            
>>>>>> +     printf_verbose("Creating trace subdirectory %s\n", path_trace);
>>>>>>
>>>>>> -     printf_verbose("Creating trace subdirectory %s\n", subtrace_name);
>>>>>> -     ret = mkdir(subtrace_name, S_IRWXU|S_IRWXG|S_IRWXO);
>>>>>> +     ret = mkdir(path_trace, S_IRWXU|S_IRWXG|S_IRWXO);
>>>>>>        if(ret == -1) {
>>>>>>                if(errno != EEXIST) {
>>>>>> -                     perror(subtrace_name);
>>>>>> +                     perror(path_trace);
>>>>>>                        open_ret = -1;
>>>>>>                        goto end;
>>>>>>                }
>>>>>>        }
>>>>>>
>>>>>> -     strncpy(path_channel, subchannel_name, PATH_MAX-1);
>>>>>> -     path_channel_len = strlen(path_channel);
>>>>>> -     path_channel[path_channel_len] = '/';
>>>>>> -     path_channel_len++;
>>>>>> -     path_channel_ptr = path_channel + path_channel_len;
>>>>>> -
>>>>>> -     strncpy(path_trace, subtrace_name, PATH_MAX-1);
>>>>>> -     path_trace_len = strlen(path_trace);
>>>>>> -     path_trace[path_trace_len] = '/';
>>>>>> -     path_trace_len++;
>>>>>> -     path_trace_ptr = path_trace + path_trace_len;
>>>>>> -
>>>>>> -#ifdef HAS_INOTIFY
>>>>>> -     iwatch_array->elem = realloc(iwatch_array->elem,
>>>>>> -             ++iwatch_array->num * sizeof(struct inotify_watch));
>>>>>> -
>>>>>> -     printf_verbose("Adding inotify for channel %s\n", path_channel);
>>>>>> -     iwatch_array->elem[iwatch_array->num-1].wd =
>>>>>>              
>>>>> inotify_add_watch(*inotify_fd, path_channel, IN_CREATE);
>>>>>            
>>>>>> -     strcpy(iwatch_array->elem[iwatch_array->num-1].path_channel,
>>>>>>              
>>>>> path_channel);
>>>>>            
>>>>>> -     strcpy(iwatch_array->elem[iwatch_array->num-1].path_trace,
>>>>>>              
>>>>> path_trace);
>>>>>            
>>>>>> -     printf_verbose("Added inotify for channel %s, wd %u\n",
>>>>>> -             iwatch_array->elem[iwatch_array->num-1].path_channel,
>>>>>> -             iwatch_array->elem[iwatch_array->num-1].wd);
>>>>>> -#endif
>>>>>> -
>>>>>> -     while((entry = readdir(channel_dir)) != NULL) {
>>>>>> -
>>>>>> -             if(entry->d_name[0] == '.') continue;
>>>>>> -
>>>>>> -             strncpy(path_channel_ptr, entry->d_name, PATH_MAX -
>>>>>>              
>>>>> path_channel_len);
>>>>>            
>>>>>> -             strncpy(path_trace_ptr, entry->d_name, PATH_MAX -
>>>>>>              
>>>>> path_trace_len);
>>>>>            
>>>>>> -
>>>>>> -             ret = stat(path_channel,&stat_buf);
>>>>>> -             if(ret == -1) {
>>>>>> -                     perror(path_channel);
>>>>>> -                     continue;
>>>>>> -             }
>>>>>> -
>>>>>> -             printf_verbose("Channel file : %s\n", path_channel);
>>>>>> -
>>>>>> -             if(S_ISDIR(stat_buf.st_mode)) {
>>>>>> -
>>>>>> -                     printf_verbose("Entering channel
>>>>>>              
>>>>> subdirectory...\n");
>>>>>            
>>>>>> -                     ret = open_channel_trace_pairs(path_channel,
>>>>>>              
>>>>> path_trace, fd_pairs,
>>>>>            
>>>>>> -                             inotify_fd, iwatch_array);
>>>>>> -                     if(ret<  0) continue;
>>>>>> -             } else if(S_ISREG(stat_buf.st_mode)) {
>>>>>> -                     open_ret = open_buffer_file(entry->d_name,
>>>>>>              
>>>>> path_channel, path_trace,
>>>>>            
>>>>>> -                             fd_pairs);
>>>>>> -                     if(open_ret)
>>>>>> -                             goto end;
>>>>>> -             }
>>>>>> -     }
>>>>>> -
>>>>>>   end:
>>>>>> -     closedir(channel_dir);
>>>>>> -
>>>>>>        return open_ret;
>>>>>>   }
>>>>>>
>>>>>> -
>>>>>> -int read_subbuffer(struct fd_pair *pair)
>>>>>> +int lttd_on_read_subbuffer(struct liblttd_callbacks *data, struct
>>>>>>              
>>>>> fd_pair *pair, unsigned int len)
>>>>>            
>>>>>>   {
>>>>>> -     unsigned int consumed_old, len;
>>>>>> -     int err;
>>>>>>        long ret;
>>>>>> -     off_t offset;
>>>>>> -
>>>>>> +     off_t offset = 0;
>>>>>>
>>>>>> -     err = ioctl(pair->channel, RELAY_GET_SB,&consumed_old);
>>>>>> -     printf_verbose("cookie : %u\n", consumed_old);
>>>>>> -     if(err != 0) {
>>>>>> -             ret = errno;
>>>>>> -             perror("Reserving sub buffer failed (everything is normal,
>>>>>>              
>>>>> it is due to concurrency)");
>>>>>            
>>>>>> -             goto get_error;
>>>>>> -     }
>>>>>> -#if 0
>>>>>> -     err = TEMP_FAILURE_RETRY(write(pair->trace,
>>>>>> -                             pair->mmap
>>>>>> -                                     + (consumed_old&  ((pair->n_subbufs
>>>>>>              
>>>>> * pair->subbuf_size)-1)),
>>>>>            
>>>>>> -                             pair->subbuf_size));
>>>>>> -
>>>>>> -     if(err<  0) {
>>>>>> -             ret = errno;
>>>>>> -             perror("Error in writing to file");
>>>>>> -             goto write_error;
>>>>>> -     }
>>>>>> -#endif //0
>>>>>> -     err = ioctl(pair->channel, RELAY_GET_SB_SIZE,&len);
>>>>>> -     if(err != 0) {
>>>>>> -             ret = errno;
>>>>>> -             perror("Getting sub-buffer len failed.");
>>>>>> -             goto get_error;
>>>>>> -     }
>>>>>> -
>>>>>> -     offset = 0;
>>>>>>        while (len>  0) {
>>>>>>                printf_verbose("splice chan to pipe offset %lu\n",
>>>>>>                        (unsigned long)offset);
>>>>>> @@ -494,8 +278,9 @@ int read_subbuffer(struct fd_pair *pair)
>>>>>>                        perror("Error in relay splice");
>>>>>>                        goto write_error;
>>>>>>                }
>>>>>> -             ret = splice(thread_pipe[0], NULL, pair->trace, NULL,
>>>>>> -                     ret, SPLICE_F_MOVE | SPLICE_F_MORE);
>>>>>> +             ret = splice(thread_pipe[0], NULL,
>>>>>> +                     ((struct lttd_channel_data
>>>>>>              
>>>>> *)(pair->user_data))->trace,
>>>>>            
>>>>>> +                     NULL, ret, SPLICE_F_MOVE | SPLICE_F_MORE);
>>>>>>                printf_verbose("splice pipe to file %ld\n", ret);
>>>>>>                if (ret<  0) {
>>>>>>                        perror("Error in file splice");
>>>>>> @@ -504,466 +289,42 @@ int read_subbuffer(struct fd_pair *pair)
>>>>>>                len -= ret;
>>>>>>        }
>>>>>>
>>>>>> -#if 0
>>>>>> -     err = fsync(pair->trace);
>>>>>> -     if(err<  0) {
>>>>>> -             ret = errno;
>>>>>> -             perror("Error in writing to file");
>>>>>> -             goto write_error;
>>>>>> -     }
>>>>>> -#endif //0
>>>>>>   write_error:
>>>>>> -     ret = 0;
>>>>>> -     err = ioctl(pair->channel, RELAY_PUT_SB,&consumed_old);
>>>>>> -     if(err != 0) {
>>>>>> -             ret = errno;
>>>>>> -             if(errno == EFAULT) {
>>>>>> -                     perror("Error in unreserving sub buffer\n");
>>>>>> -             } else if(errno == EIO) {
>>>>>> -                     /* Should never happen with newer LTTng versions */
>>>>>> -                     perror("Reader has been pushed by the writer, last
>>>>>>              
>>>>> sub-buffer corrupted.");
>>>>>            
>>>>>> -             }
>>>>>> -             goto get_error;
>>>>>> -     }
>>>>>> -
>>>>>> -get_error:
>>>>>> -     return ret;
>>>>>> -}
>>>>>> -
>>>>>> -
>>>>>> -int map_channels(struct channel_trace_fd *fd_pairs,
>>>>>> -     int idx_begin, int idx_end)
>>>>>> -{
>>>>>> -     int i,j;
>>>>>> -     int ret=0;
>>>>>> -
>>>>>> -     if(fd_pairs->num_pairs<= 0) {
>>>>>> -             printf("No channel to read\n");
>>>>>> -             goto end;
>>>>>> -     }
>>>>>> -
>>>>>> -     /* Get the subbuf sizes and number */
>>>>>> -
>>>>>> -     for(i=idx_begin;i<idx_end;i++) {
>>>>>> -             struct fd_pair *pair =&fd_pairs->pair[i];
>>>>>> -
>>>>>> -             ret = ioctl(pair->channel, RELAY_GET_N_SB,&pair->n_sb);
>>>>>> -             if(ret != 0) {
>>>>>> -                     perror("Error in getting the number of
>>>>>>              
>>>>> sub-buffers");
>>>>>            
>>>>>> -                     goto end;
>>>>>> -             }
>>>>>> -             ret = ioctl(pair->channel, RELAY_GET_MAX_SB_SIZE,
>>>>>> -&pair->max_sb_size);
>>>>>> -             if(ret != 0) {
>>>>>> -                     perror("Error in getting the max sub-buffer size");
>>>>>> -                     goto end;
>>>>>> -             }
>>>>>> -             ret = pthread_mutex_init(&pair->mutex, NULL);   /* Fast
>>>>>>              
>>>>> mutex */
>>>>>            
>>>>>> -             if(ret != 0) {
>>>>>> -                     perror("Error in mutex init");
>>>>>> -                     goto end;
>>>>>> -             }
>>>>>> -     }
>>>>>> -
>>>>>> -#if 0
>>>>>> -     /* Mmap each FD */
>>>>>> -     for(i=idx_begin;i<idx_end;i++) {
>>>>>> -             struct fd_pair *pair =&fd_pairs->pair[i];
>>>>>> -
>>>>>> -             pair->mmap = mmap(0, pair->subbuf_size * pair->n_subbufs,
>>>>>>              
>>>>> PROT_READ,
>>>>>            
>>>>>> -                             MAP_SHARED, pair->channel, 0);
>>>>>> -             if(pair->mmap == MAP_FAILED) {
>>>>>> -                     perror("Mmap error");
>>>>>> -                     goto munmap;
>>>>>> -             }
>>>>>> -     }
>>>>>> -
>>>>>> -     goto end; /* success */
>>>>>> -
>>>>>> -     /* Error handling */
>>>>>> -     /* munmap only the successfully mmapped indexes */
>>>>>> -munmap:
>>>>>> -             /* Munmap each FD */
>>>>>> -     for(j=idx_begin;j<i;j++) {
>>>>>> -             struct fd_pair *pair =&fd_pairs->pair[j];
>>>>>> -             int err_ret;
>>>>>> -
>>>>>> -             err_ret = munmap(pair->mmap, pair->subbuf_size *
>>>>>>              
>>>>> pair->n_subbufs);
>>>>>            
>>>>>> -             if(err_ret != 0) {
>>>>>> -                     perror("Error in munmap");
>>>>>> -             }
>>>>>> -             ret |= err_ret;
>>>>>> -     }
>>>>>> -
>>>>>> -#endif //0
>>>>>> -end:
>>>>>>        return ret;
>>>>>>   }
>>>>>>
>>>>>> -int unmap_channels(struct channel_trace_fd *fd_pairs)
>>>>>> -{
>>>>>> -     int j;
>>>>>> -     int ret=0;
>>>>>> -
>>>>>> -     /* Munmap each FD */
>>>>>> -     for(j=0;j<fd_pairs->num_pairs;j++) {
>>>>>> -             struct fd_pair *pair =&fd_pairs->pair[j];
>>>>>> -             int err_ret;
>>>>>> -
>>>>>> -#if 0
>>>>>> -             err_ret = munmap(pair->mmap, pair->subbuf_size *
>>>>>>              
>>>>> pair->n_subbufs);
>>>>>            
>>>>>> -             if(err_ret != 0) {
>>>>>> -                     perror("Error in munmap");
>>>>>> -             }
>>>>>> -             ret |= err_ret;
>>>>>> -#endif //0
>>>>>> -             err_ret = pthread_mutex_destroy(&pair->mutex);
>>>>>> -             if(err_ret != 0) {
>>>>>> -                     perror("Error in mutex destroy");
>>>>>> -             }
>>>>>> -             ret |= err_ret;
>>>>>> -     }
>>>>>> -
>>>>>> -     return ret;
>>>>>> -}
>>>>>> -
>>>>>> -#ifdef HAS_INOTIFY
>>>>>> -/* Inotify event arrived.
>>>>>> - *
>>>>>> - * Only support add file for now.
>>>>>> - */
>>>>>> -
>>>>>> -int read_inotify(int inotify_fd,
>>>>>> -     struct channel_trace_fd *fd_pairs,
>>>>>> -     struct inotify_watch_array *iwatch_array)
>>>>>> -{
>>>>>> -     char buf[sizeof(struct inotify_event) + PATH_MAX];
>>>>>> -     char path_channel[PATH_MAX];
>>>>>> -     char path_trace[PATH_MAX];
>>>>>> -     ssize_t len;
>>>>>> -     struct inotify_event *ievent;
>>>>>> -     size_t offset;
>>>>>> -     unsigned int i;
>>>>>> -     int ret;
>>>>>> -     int old_num;
>>>>>> -
>>>>>> -     offset = 0;
>>>>>> -     len = read(inotify_fd, buf, sizeof(struct inotify_event) +
>>>>>>              
>>>>> PATH_MAX);
>>>>>            
>>>>>> -     if(len<  0) {
>>>>>> -
>>>>>> -             if(errno == EAGAIN)
>>>>>> -                     return 0;  /* another thread got the data before us
>>>>>>              
>>>>> */
>>>>>            
>>>>>> -
>>>>>> -             printf("Error in read from inotify FD %s.\n",
>>>>>>              
>>>>> strerror(len));
>>>>>            
>>>>>> -             return -1;
>>>>>> -     }
>>>>>> -     while(offset<  len) {
>>>>>> -             ievent = (struct inotify_event *)&(buf[offset]);
>>>>>> -             for(i=0; i<iwatch_array->num; i++) {
>>>>>> -                     if(iwatch_array->elem[i].wd == ievent->wd&&
>>>>>> -                             ievent->mask == IN_CREATE) {
>>>>>> -                             printf_verbose(
>>>>>> -                                     "inotify wd %u event mask : %u for
>>>>>>              
>>>>> %s%s\n",
>>>>>            
>>>>>> -                                     ievent->wd, ievent->mask,
>>>>>> -                                     iwatch_array->elem[i].path_channel,
>>>>>> -                                     ievent->name);
>>>>>> -                             old_num = fd_pairs->num_pairs;
>>>>>> -                             strcpy(path_channel,
>>>>>>              
>>>>> iwatch_array->elem[i].path_channel);
>>>>>            
>>>>>> -                             strcat(path_channel, ievent->name);
>>>>>> -                             strcpy(path_trace,
>>>>>>              
>>>>> iwatch_array->elem[i].path_trace);
>>>>>            
>>>>>> -                             strcat(path_trace, ievent->name);
>>>>>> -                             if(ret = open_buffer_file(ievent->name,
>>>>>>              
>>>>> path_channel,
>>>>>            
>>>>>> -                                     path_trace, fd_pairs)) {
>>>>>> -                                     printf("Error opening buffer
>>>>>>              
>>>>> file\n");
>>>>>            
>>>>>> -                                     return -1;
>>>>>> -                             }
>>>>>> -                             if(ret = map_channels(fd_pairs, old_num,
>>>>>>              
>>>>> fd_pairs->num_pairs)) {
>>>>>            
>>>>>> -                                     printf("Error mapping channel\n");
>>>>>> -                                     return -1;
>>>>>> -                             }
>>>>>> -
>>>>>> -                     }
>>>>>> -             }
>>>>>> -             offset += sizeof(*ievent) + ievent->len;
>>>>>> -     }
>>>>>> -}
>>>>>> -#endif //HAS_INOTIFY
>>>>>> -
>>>>>> -/* read_channels
>>>>>> - *
>>>>>> - * Thread worker.
>>>>>> - *
>>>>>> - * Read the debugfs channels and write them in the paired tracefiles.
>>>>>> - *
>>>>>> - * @fd_pairs : paired channels and trace files.
>>>>>> - *
>>>>>> - * returns 0 on success, -1 on error.
>>>>>> - *
>>>>>> - * Note that the high priority polled channels are consumed first. We
>>>>>>              
>>>>> then poll
>>>>>            
>>>>>> - * again to see if these channels are still in priority. Only when no
>>>>>> - * high priority channel is left, we start reading low priority
>>>>>>              
>>>>> channels.
>>>>>            
>>>>>> - *
>>>>>> - * Note that a channel is considered high priority when the buffer is
>>>>>>              
>>>>> almost
>>>>>            
>>>>>> - * full.
>>>>>> - */
>>>>>> -
>>>>>> -int read_channels(unsigned long thread_num, struct channel_trace_fd
>>>>>>              
>>>>> *fd_pairs,
>>>>>            
>>>>>> -     int inotify_fd, struct inotify_watch_array *iwatch_array)
>>>>>> -{
>>>>>> -     struct pollfd *pollfd = NULL;
>>>>>> -     int num_pollfd;
>>>>>> -     int i,j;
>>>>>> -     int num_rdy, num_hup;
>>>>>> -     int high_prio;
>>>>>> -     int ret = 0;
>>>>>> -     int inotify_fds;
>>>>>> -     unsigned int old_num;
>>>>>> -
>>>>>> -#ifdef HAS_INOTIFY
>>>>>> -     inotify_fds = 1;
>>>>>> -#else
>>>>>> -     inotify_fds = 0;
>>>>>> -#endif
>>>>>> -
>>>>>> -     pthread_rwlock_rdlock(&fd_pairs_lock);
>>>>>> -
>>>>>> -     /* Start polling the FD. Keep one fd for inotify */
>>>>>> -     pollfd = malloc((inotify_fds + fd_pairs->num_pairs) * sizeof(struct
>>>>>>              
>>>>> pollfd));
>>>>>            
>>>>>> -
>>>>>> -#ifdef HAS_INOTIFY
>>>>>> -     pollfd[0].fd = inotify_fd;
>>>>>> -     pollfd[0].events = POLLIN|POLLPRI;
>>>>>> -#endif
>>>>>> -
>>>>>> -     for(i=0;i<fd_pairs->num_pairs;i++) {
>>>>>> -             pollfd[inotify_fds+i].fd = fd_pairs->pair[i].channel;
>>>>>> -             pollfd[inotify_fds+i].events = POLLIN|POLLPRI;
>>>>>> -     }
>>>>>> -     num_pollfd = inotify_fds + fd_pairs->num_pairs;
>>>>>> -
>>>>>> -
>>>>>> -     pthread_rwlock_unlock(&fd_pairs_lock);
>>>>>> -
>>>>>> -     while(1) {
>>>>>> -             high_prio = 0;
>>>>>> -             num_hup = 0;
>>>>>> -#ifdef DEBUG
>>>>>> -             printf("Press a key for next poll...\n");
>>>>>> -             char buf[1];
>>>>>> -             read(STDIN_FILENO,&buf, 1);
>>>>>> -             printf("Next poll (polling %d fd) :\n", num_pollfd);
>>>>>> -#endif //DEBUG
>>>>>> -
>>>>>> -             /* Have we received a signal ? */
>>>>>> -             if(quit_program) break;
>>>>>> -
>>>>>> -             num_rdy = poll(pollfd, num_pollfd, -1);
>>>>>> -
>>>>>> -             if(num_rdy == -1) {
>>>>>> -                     perror("Poll error");
>>>>>> -                     goto free_fd;
>>>>>> -             }
>>>>>> -
>>>>>> -             printf_verbose("Data received\n");
>>>>>> -#ifdef HAS_INOTIFY
>>>>>> -             switch(pollfd[0].revents) {
>>>>>> -                     case POLLERR:
>>>>>> -                             printf_verbose(
>>>>>> -                                     "Error returned in polling inotify
>>>>>>              
>>>>> fd %d.\n",
>>>>>            
>>>>>> -                                     pollfd[0].fd);
>>>>>> -                             break;
>>>>>> -                     case POLLHUP:
>>>>>> -                             printf_verbose(
>>>>>> -                                     "Polling inotify fd %d tells it has
>>>>>>              
>>>>> hung up.\n",
>>>>>            
>>>>>> -                                     pollfd[0].fd);
>>>>>> -                             break;
>>>>>> -                     case POLLNVAL:
>>>>>> -                             printf_verbose(
>>>>>> -                                     "Polling inotify fd %d tells fd is
>>>>>>              
>>>>> not open.\n",
>>>>>            
>>>>>> -                                     pollfd[0].fd);
>>>>>> -                             break;
>>>>>> -                     case POLLPRI:
>>>>>> -                     case POLLIN:
>>>>>> -                             printf_verbose(
>>>>>> -                                     "Polling inotify fd %d : data
>>>>>>              
>>>>> ready.\n",
>>>>>            
>>>>>> -                                     pollfd[0].fd);
>>>>>> -
>>>>>> -                             pthread_rwlock_wrlock(&fd_pairs_lock);
>>>>>> -                             read_inotify(inotify_fd, fd_pairs,
>>>>>>              
>>>>> iwatch_array);
>>>>>            
>>>>>> -                             pthread_rwlock_unlock(&fd_pairs_lock);
>>>>>> -
>>>>>> -                     break;
>>>>>> -             }
>>>>>> -#endif
>>>>>> -
>>>>>> -             for(i=inotify_fds;i<num_pollfd;i++) {
>>>>>> -                     switch(pollfd[i].revents) {
>>>>>> -                             case POLLERR:
>>>>>> -                                     printf_verbose(
>>>>>> -                                             "Error returned in polling
>>>>>>              
>>>>> fd %d.\n",
>>>>>            
>>>>>> -                                             pollfd[i].fd);
>>>>>> -                                     num_hup++;
>>>>>> -                                     break;
>>>>>> -                             case POLLHUP:
>>>>>> -                                     printf_verbose(
>>>>>> -                                             "Polling fd %d tells it has
>>>>>>              
>>>>> hung up.\n",
>>>>>            
>>>>>> -                                             pollfd[i].fd);
>>>>>> -                                     num_hup++;
>>>>>> -                                     break;
>>>>>> -                             case POLLNVAL:
>>>>>> -                                     printf_verbose(
>>>>>> -                                             "Polling fd %d tells fd is
>>>>>>              
>>>>> not open.\n",
>>>>>            
>>>>>> -                                             pollfd[i].fd);
>>>>>> -                                     num_hup++;
>>>>>> -                                     break;
>>>>>> -                             case POLLPRI:
>>>>>> -
>>>>>>              
>>>>> pthread_rwlock_rdlock(&fd_pairs_lock);
>>>>>            
>>>>>> -
>>>>>>              
>>>>> if(pthread_mutex_trylock(&fd_pairs->pair[i-inotify_fds].mutex) == 0) {
>>>>>            
>>>>>> -                                             printf_verbose(
>>>>>> -                                                     "Urgent read on fd
>>>>>>              
>>>>> %d\n",
>>>>>            
>>>>>> -                                                     pollfd[i].fd);
>>>>>> -                                             /* Take care of high
>>>>>>              
>>>>> priority channels first. */
>>>>>            
>>>>>> -                                             high_prio = 1;
>>>>>> -                                             /* it's ok to have an
>>>>>>              
>>>>> unavailable sub-buffer */
>>>>>            
>>>>>> -                                             ret =
>>>>>>              
>>>>> read_subbuffer(&fd_pairs->pair[i-inotify_fds]);
>>>>>            
>>>>>> -                                             if(ret == EAGAIN) ret = 0;
>>>>>> -
>>>>>> -                                             ret =
>>>>>>              
>>>>> pthread_mutex_unlock(&fd_pairs->pair[i-inotify_fds].mutex);
>>>>>            
>>>>>> -                                             if(ret)
>>>>>> -                                                     printf("Error in
>>>>>>              
>>>>> mutex unlock : %s\n", strerror(ret));
>>>>>            
>>>>>> -                                     }
>>>>>> -
>>>>>>              
>>>>> pthread_rwlock_unlock(&fd_pairs_lock);
>>>>>            
>>>>>> -                                     break;
>>>>>> -                     }
>>>>>> -             }
>>>>>> -             /* If every buffer FD has hung up, we end the read loop
>>>>>>              
>>>>> here */
>>>>>            
>>>>>> -             if(num_hup == num_pollfd - inotify_fds) break;
>>>>>> -
>>>>>> -             if(!high_prio) {
>>>>>> -                     for(i=inotify_fds;i<num_pollfd;i++) {
>>>>>> -                             switch(pollfd[i].revents) {
>>>>>> -                                     case POLLIN:
>>>>>> -
>>>>>>              
>>>>> pthread_rwlock_rdlock(&fd_pairs_lock);
>>>>>            
>>>>>> -
>>>>>>              
>>>>> if(pthread_mutex_trylock(&fd_pairs->pair[i-inotify_fds].mutex) == 0) {
>>>>>            
>>>>>> -                                                     /* Take care of low
>>>>>>              
>>>>> priority channels. */
>>>>>            
>>>>>> -                                                     printf_verbose(
>>>>>> -                                                             "Normal
>>>>>>              
>>>>> read on fd %d\n",
>>>>>            
>>>>>> -
>>>>>>              
>>>>> pollfd[i].fd);
>>>>>            
>>>>>> -                                                     /* it's ok to have
>>>>>>              
>>>>> an unavailable subbuffer */
>>>>>            
>>>>>> -                                                     ret =
>>>>>>              
>>>>> read_subbuffer(&fd_pairs->pair[i-inotify_fds]);
>>>>>            
>>>>>> -                                                     if(ret == EAGAIN)
>>>>>>              
>>>>> ret = 0;
>>>>>            
>>>>>> -
>>>>>> -                                                     ret =
>>>>>>              
>>>>> pthread_mutex_unlock(&fd_pairs->pair[i-inotify_fds].mutex);
>>>>>            
>>>>>> -                                                     if(ret)
>>>>>> -
>>>>>>              
>>>>> printf("Error in mutex unlock : %s\n", strerror(ret));
>>>>>            
>>>>>> -                                             }
>>>>>> -
>>>>>>              
>>>>> pthread_rwlock_unlock(&fd_pairs_lock);
>>>>>            
>>>>>> -                                             break;
>>>>>> -                             }
>>>>>> -                     }
>>>>>> -             }
>>>>>> -
>>>>>> -             /* Update pollfd array if an entry was added to fd_pairs */
>>>>>> -             pthread_rwlock_rdlock(&fd_pairs_lock);
>>>>>> -             if((inotify_fds + fd_pairs->num_pairs) != num_pollfd) {
>>>>>> -                     pollfd = realloc(pollfd,
>>>>>> -                                     (inotify_fds + fd_pairs->num_pairs)
>>>>>>              
>>>>> * sizeof(struct pollfd));
>>>>>            
>>>>>> -
>>>>>>              
>>>>> for(i=num_pollfd-inotify_fds;i<fd_pairs->num_pairs;i++) {
>>>>>            
>>>>>> -                             pollfd[inotify_fds+i].fd =
>>>>>>              
>>>>> fd_pairs->pair[i].channel;
>>>>>            
>>>>>> -                             pollfd[inotify_fds+i].events =
>>>>>>              
>>>>> POLLIN|POLLPRI;
>>>>>            
>>>>>> -                     }
>>>>>> -                     num_pollfd = fd_pairs->num_pairs + inotify_fds;
>>>>>> -             }
>>>>>> -             pthread_rwlock_unlock(&fd_pairs_lock);
>>>>>> -
>>>>>> -             /* NB: If the fd_pairs structure is updated by another
>>>>>>              
>>>>> thread from this
>>>>>            
>>>>>> -              *     point forward, the current thread will wait in the
>>>>>>              
>>>>> poll without
>>>>>            
>>>>>> -              *     monitoring the new channel. However, this thread
>>>>>>              
>>>>> will add the
>>>>>            
>>>>>> -              *     new channel on next poll (and this should not take
>>>>>>              
>>>>> too much time
>>>>>            
>>>>>> -              *     on a loaded system).
>>>>>> -              *
>>>>>> -              *     This event is quite unlikely and can only occur if a
>>>>>>              
>>>>> CPU is
>>>>>            
>>>>>> -              *     hot-plugged while multple lttd threads are running.
>>>>>> -              */
>>>>>> -     }
>>>>>> -
>>>>>> -free_fd:
>>>>>> -     free(pollfd);
>>>>>> -
>>>>>> -end:
>>>>>> -     return ret;
>>>>>> -}
>>>>>> -
>>>>>> -
>>>>>> -void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs, int
>>>>>>              
>>>>> inotify_fd,
>>>>>            
>>>>>> -     struct inotify_watch_array *iwatch_array)
>>>>>> -{
>>>>>> -     int i;
>>>>>> +int on_new_thread(struct liblttd_callbacks *data, unsigned long
>>>>>>              
>>>>> thread_num) {
>>>>>            
>>>>>>        int ret;
>>>>>> -
>>>>>> -     for(i=0;i<fd_pairs->num_pairs;i++) {
>>>>>> -             ret = close(fd_pairs->pair[i].channel);
>>>>>> -             if(ret == -1) perror("Close error on channel");
>>>>>> -             ret = close(fd_pairs->pair[i].trace);
>>>>>> -             if(ret == -1) perror("Close error on trace");
>>>>>> -     }
>>>>>> -     free(fd_pairs->pair);
>>>>>> -     free(iwatch_array->elem);
>>>>>> -}
>>>>>> -
>>>>>> -/* Thread worker */
>>>>>> -void * thread_main(void *arg)
>>>>>> -{
>>>>>> -     long ret;
>>>>>> -     unsigned long thread_num = (unsigned long)arg;
>>>>>> -
>>>>>>        ret = pipe(thread_pipe);
>>>>>>        if (ret<  0) {
>>>>>>                perror("Error creating pipe");
>>>>>> -             return (void*)ret;
>>>>>> +             return ret;
>>>>>>        }
>>>>>> -     ret = read_channels(thread_num,&fd_pairs, inotify_fd,
>>>>>>              
>>>>> &inotify_watch_array);
>>>>>            
>>>>>> -     close(thread_pipe[0]);  /* close read end */
>>>>>> -     close(thread_pipe[1]);  /* close write end */
>>>>>> -     return (void*)ret;
>>>>>> +     return 0;
>>>>>>   }
>>>>>>
>>>>>> -
>>>>>> -int channels_init()
>>>>>> -{
>>>>>> -     int ret = 0;
>>>>>> -
>>>>>> -     inotify_fd = inotify_init();
>>>>>> -     fcntl(inotify_fd, F_SETFL, O_NONBLOCK);
>>>>>> -
>>>>>> -     if(ret = open_channel_trace_pairs(channel_name, trace_name,
>>>>>>              
>>>>> &fd_pairs,
>>>>>            
>>>>>> -&inotify_fd,&inotify_watch_array))
>>>>>> -             goto close_channel;
>>>>>> -     if (fd_pairs.num_pairs == 0) {
>>>>>> -             printf("No channel available for reading, exiting\n");
>>>>>> -             ret = -ENOENT;
>>>>>> -             goto close_channel;
>>>>>> -     }
>>>>>> -     if(ret = map_channels(&fd_pairs, 0, fd_pairs.num_pairs))
>>>>>> -             goto close_channel;
>>>>>> +int on_close_thread(struct liblttd_callbacks *data, unsigned long
>>>>>>              
>>>>> thread_num) {
>>>>>            
>>>>>> +     close(thread_pipe[0]);  /* close read end */
>>>>>> +     close(thread_pipe[1]);  /* close write end */
>>>>>>        return 0;
>>>>>> -
>>>>>> -close_channel:
>>>>>> -     close_channel_trace_pairs(&fd_pairs, inotify_fd,
>>>>>>              
>>>>> &inotify_watch_array);
>>>>>            
>>>>>> -     if(inotify_fd>= 0)
>>>>>> -             close(inotify_fd);
>>>>>> -     return ret;
>>>>>>   }
>>>>>>
>>>>>> -
>>>>>>   int main(int argc, char ** argv)
>>>>>>   {
>>>>>>        int ret = 0;
>>>>>>        struct sigaction act;
>>>>>> -     pthread_t *tids;
>>>>>> -     unsigned long i;
>>>>>> -     void *tret;
>>>>>> -
>>>>>> +
>>>>>> +     struct liblttd_callbacks callbacks = {
>>>>>> +             lttd_on_open_channel,
>>>>>> +             lttd_on_close_channel,
>>>>>> +             lttd_on_new_channels_folder,
>>>>>> +             lttd_on_read_subbuffer,
>>>>>> +             NULL,
>>>>>> +             on_new_thread,
>>>>>> +             on_close_thread,
>>>>>> +             NULL
>>>>>> +     };
>>>>>> +
>>>>>>        ret = parse_arguments(argc, argv);
>>>>>>
>>>>>>        if(ret != 0) show_arguments();
>>>>>> @@ -983,9 +344,6 @@ int main(int argc, char ** argv)
>>>>>>        sigaction(SIGQUIT,&act, NULL);
>>>>>>        sigaction(SIGINT,&act, NULL);
>>>>>>
>>>>>> -     if(ret = channels_init())
>>>>>> -             return ret;
>>>>>> -
>>>>>>        if(daemon_mode) {
>>>>>>                ret = daemon(0, 0);
>>>>>>
>>>>>> @@ -995,33 +353,13 @@ int main(int argc, char ** argv)
>>>>>>                }
>>>>>>        }
>>>>>>
>>>>>> -     tids = malloc(sizeof(pthread_t) * num_threads);
>>>>>> -     for(i=0; i<num_threads; i++) {
>>>>>> -
>>>>>> -             ret = pthread_create(&tids[i], NULL, thread_main,
>>>>>>              
>>>>> (void*)i);
>>>>>            
>>>>>> -             if(ret) {
>>>>>> -                     perror("Error creating thread");
>>>>>> -                     break;
>>>>>> -             }
>>>>>> -     }
>>>>>> +     strncpy(path_trace, trace_name, PATH_MAX-1);
>>>>>> +     path_trace_len = strlen(path_trace);
>>>>>> +     end_path_trace = path_trace + path_trace_len;
>>>>>>
>>>>>> -     for(i=0; i<num_threads; i++) {
>>>>>> -             ret = pthread_join(tids[i],&tret);
>>>>>> -             if(ret) {
>>>>>> -                     perror("Error joining thread");
>>>>>> -                     break;
>>>>>> -             }
>>>>>> -             if((long)tret != 0) {
>>>>>> -                     printf("Error %s occured in thread %u\n",
>>>>>> -                             strerror((long)tret), i);
>>>>>> -             }
>>>>>> -     }
>>>>>> +     liblttd_start(channel_name, num_threads, dump_flight_only,
>>>>>>              
>>>>> dump_normal_only,
>>>>>            
>>>>>> +             verbose_mode,&callbacks);
>>>>>>
>>>>>> -     free(tids);
>>>>>> -     ret = unmap_channels(&fd_pairs);
>>>>>> -     close_channel_trace_pairs(&fd_pairs, inotify_fd,
>>>>>>              
>>>>> &inotify_watch_array);
>>>>>            
>>>>>> -     if(inotify_fd>= 0)
>>>>>> -             close(inotify_fd);
>>>>>> -
>>>>>>        return ret;
>>>>>>   }
>>>>>> +
>>>>>>              
>>>>>
>>>>> --
>>>>> Mathieu Desnoyers
>>>>> OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
>>>>>
>>>>>            
>>>        
>>>> diff --git a/Makefile.am b/Makefile.am
>>>> index 8f9974d..06500fd 100644
>>>> --- a/Makefile.am
>>>> +++ b/Makefile.am
>>>> @@ -1,2 +1,2 @@
>>>> -SUBDIRS = liblttctl lttctl lttd specs
>>>> +SUBDIRS = liblttctl lttctl liblttd lttd specs
>>>>
>>>> diff --git a/configure.in b/configure.in
>>>> index d67e7d4..a992cd8 100644
>>>> --- a/configure.in
>>>> +++ b/configure.in
>>>> @@ -76,8 +76,10 @@ DEFAULT_INCLUDES="-I\$(top_srcdir) -I\$(top_builddir)"
>>>>   #AC_SUBST(CPPFLAGS)
>>>>
>>>>   lttctlincludedir="${includedir}/liblttctl"
>>>> +liblttdincludedir="${includedir}/liblttd"
>>>>
>>>>   AC_SUBST(lttctlincludedir)
>>>> +AC_SUBST(liblttdincludedir)
>>>>   AC_SUBST(UTIL_LIBS)
>>>>   AC_SUBST(THREAD_LIBS)
>>>>   AC_SUBST(DEFAULT_INCLUDES)
>>>> @@ -85,6 +87,7 @@ AC_SUBST(DEFAULT_INCLUDES)
>>>>   AC_CONFIG_FILES([Makefile
>>>>        liblttctl/Makefile
>>>>        lttctl/Makefile
>>>> +     liblttd/Makefile
>>>>        lttd/Makefile
>>>>        specs/Makefile])
>>>>   AC_OUTPUT
>>>> diff --git a/liblttd/Makefile.am b/liblttd/Makefile.am
>>>> new file mode 100644
>>>> index 0000000..3c1eeda
>>>> --- /dev/null
>>>> +++ b/liblttd/Makefile.am
>>>> @@ -0,0 +1,7 @@
>>>> +
>>>> +
>>>> +lib_LTLIBRARIES = liblttd.la
>>>> +liblttd_la_SOURCES = liblttd.c
>>>> +
>>>> +liblttdinclude_HEADERS = \
>>>> +	liblttd.h
>>>> diff --git a/liblttd/liblttd.c b/liblttd/liblttd.c
>>>> new file mode 100644
>>>> index 0000000..0f0e5b5
>>>> --- /dev/null
>>>> +++ b/liblttd/liblttd.c
>>>> @@ -0,0 +1,747 @@
>>>> +/* lttd
>>>> + *
>>>> + * Linux Trace Toolkit Daemon
>>>> + *
>>>> + * This is a simple daemon that reads a few relay+debugfs channels and save
>>>> + * them in a trace.
>>>> + *
>>>> + * CPU hot-plugging is supported using inotify.
>>>> + *
>>>> + * Copyright 2005 -
>>>> + * 	Mathieu Desnoyers<mathieu.desnoyers at polymtl.ca>
>>>> + */
>>>> +
>>>> +#ifdef HAVE_CONFIG_H
>>>> +#include<config.h>
>>>> +#endif
>>>> +
>>>> +#include "liblttd.h"
>>>> +
>>>> +#define _REENTRANT
>>>> +#define _GNU_SOURCE
>>>> +#include<features.h>
>>>> +#include<stdio.h>
>>>> +#include<unistd.h>
>>>> +#include<errno.h>
>>>> +#include<sys/types.h>
>>>> +#include<stdlib.h>
>>>> +#include<dirent.h>
>>>> +#include<string.h>
>>>> +#include<fcntl.h>
>>>> +#include<sys/stat.h>
>>>> +#include<sys/poll.h>
>>>> +#include<sys/mman.h>
>>>> +#include<sys/syscall.h>
>>>> +#include<unistd.h>
>>>> +#include<asm/ioctls.h>
>>>> +
>>>> +#include<linux/version.h>
>>>> +
>>>> +/* Relayfs IOCTL */
>>>> +#include<asm/ioctl.h>
>>>> +#include<asm/types.h>
>>>> +
>>>> +/* Get the next sub buffer that can be read. */
>>>> +#define RELAY_GET_SB		_IOR(0xF5, 0x00,__u32)
>>>> +/* Release the oldest reserved (by "get") sub buffer. */
>>>> +#define RELAY_PUT_SB		_IOW(0xF5, 0x01,__u32)
>>>> +/* returns the number of sub buffers in the per cpu channel. */
>>>> +#define RELAY_GET_N_SB		_IOR(0xF5, 0x02,__u32)
>>>> +/* returns the size of the current sub buffer. */
>>>> +#define RELAY_GET_SB_SIZE	_IOR(0xF5, 0x03, __u32)
>>>> +/* returns the size of data to consume in the current sub-buffer. */
>>>> +#define RELAY_GET_MAX_SB_SIZE	_IOR(0xF5, 0x04, __u32)
>>>> +
>>>> +
>>>> +#if LINUX_VERSION_CODE>= KERNEL_VERSION(2,6,14)
>>>> +#include<sys/inotify.h>
>>>> +
>>>> +#define HAS_INOTIFY
>>>> +#else
>>>> +static inline int inotify_init (void)
>>>> +{
>>>> +	return -1;
>>>> +}
>>>> +
>>>> +static inline int inotify_add_watch (int fd, const char *name, __u32 mask)
>>>> +{
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static inline int inotify_rm_watch (int fd, __u32 wd)
>>>> +{
>>>> +	return 0;
>>>> +}
>>>> +#undef HAS_INOTIFY
>>>> +#endif
>>>> +
>>>> +struct liblttd_callbacks *callbacks;
>>>> +
>>>> +struct channel_trace_fd {
>>>> +	struct fd_pair *pair;
>>>> +	int num_pairs;
>>>> +};
>>>> +
>>>> +struct inotify_watch {
>>>> +	int wd;
>>>> +	char path_channel[PATH_MAX];
>>>> +	char *base_path_channel;
>>>> +};
>>>> +
>>>> +struct inotify_watch_array {
>>>> +	struct inotify_watch *elem;
>>>> +	int num;
>>>> +};
>>>> +
>>>> +struct channel_trace_fd fd_pairs = { NULL, 0 };
>>>> +int inotify_fd = -1;
>>>> +struct inotify_watch_array inotify_watch_array = { NULL, 0 };
>>>> +
>>>> +/* protects fd_pairs and inotify_watch_array */
>>>> +pthread_rwlock_t fd_pairs_lock = PTHREAD_RWLOCK_INITIALIZER;
>>>> +
>>>> +static char		*channel_name = NULL;
>>>> +static unsigned long	num_threads = 1;
>>>> +volatile static int	quit_program = 0;	/* For signal handler */
>>>> +static int		dump_flight_only = 0;
>>>> +static int		dump_normal_only = 0;
>>>> +static int		verbose_mode = 0;
>>>> +
>>>> +#define printf_verbose(fmt, args...) \
>>>> +  do {                               \
>>>> +    if (verbose_mode)                \
>>>> +      printf(fmt, ##args);           \
>>>> +  } while (0)
>>>> +
>>>> +
>>>> +int open_buffer_file(char *filename, char *path_channel,
>>>> +	char *base_path_channel, struct channel_trace_fd *fd_pairs)
>>>> +{
>>>> +	int open_ret = 0;
>>>> +	int ret = 0;
>>>> +
>>>> +	if(strncmp(filename, "flight-", sizeof("flight-")-1) != 0) {
>>>> +		if(dump_flight_only) {
>>>> +			printf_verbose("Skipping normal channel %s\n",
>>>> +				path_channel);
>>>> +			return 0;
>>>> +		}
>>>> +	} else {
>>>> +		if(dump_normal_only) {
>>>> +			printf_verbose("Skipping flight channel %s\n",
>>>> +				path_channel);
>>>> +			return 0;
>>>> +		}
>>>> +	}
>>>> +	printf_verbose("Opening file.\n");
>>>> +
>>>> +	fd_pairs->pair = realloc(fd_pairs->pair,
>>>> +			++fd_pairs->num_pairs * sizeof(struct fd_pair));
>>>> +
>>>> +	/* Open the channel in read mode */
>>>> +	fd_pairs->pair[fd_pairs->num_pairs-1].channel =
>>>> +		open(path_channel, O_RDONLY | O_NONBLOCK);
>>>> +	if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) {
>>>> +		perror(path_channel);
>>>> +		fd_pairs->num_pairs--;
>>>> +		return 0;	/* continue */
>>>> +	}
>>>> +
>>>> +	if(callbacks->on_open_channel) ret = callbacks->on_open_channel(
>>>> +			callbacks,&fd_pairs->pair[fd_pairs->num_pairs-1],
>>>> +			base_path_channel);
>>>> +
>>>> +	if(ret != 0) {
>>>> +		open_ret = -1;
>>>> +		close(fd_pairs->pair[fd_pairs->num_pairs-1].channel);
>>>> +		fd_pairs->num_pairs--;
>>>> +		goto end;
>>>> +	}
>>>> +
>>>> +end:
>>>> +	return open_ret;
>>>> +}
>>>> +
>>>> +int open_channel_trace_pairs(char *subchannel_name,
>>>> +		char *base_subchannel_name,
>>>> +		struct channel_trace_fd *fd_pairs, int *inotify_fd,
>>>> +		struct inotify_watch_array *iwatch_array)
>>>> +{
>>>> +	DIR *channel_dir = opendir(subchannel_name);
>>>> +	struct dirent *entry;
>>>> +	struct stat stat_buf;
>>>> +	int ret;
>>>> +	char path_channel[PATH_MAX];
>>>> +	int path_channel_len;
>>>> +	char *path_channel_ptr;
>>>> +	char *base_subchannel_ptr;
>>>> +
>>>> +	int open_ret = 0;
>>>> +
>>>> +	if(channel_dir == NULL) {
>>>> +		perror(subchannel_name);
>>>> +		open_ret = ENOENT;
>>>> +		goto end;
>>>> +	}
>>>> +
>>>> +	printf_verbose("Calling on new channels folder");
>>>> +	if(callbacks->on_new_channels_folder) ret = callbacks->
>>>> +			on_new_channels_folder(callbacks,
>>>> +			base_subchannel_name);
>>>> +	if(ret == -1) {
>>>> +		open_ret = -1;
>>>> +		goto end;
>>>> +	}
>>>> +
>>>> +	strncpy(path_channel, subchannel_name, PATH_MAX-1);
>>>> +	path_channel_len = strlen(path_channel);
>>>> +	path_channel[path_channel_len] = '/';
>>>> +	path_channel_len++;
>>>> +	path_channel_ptr = path_channel + path_channel_len;
>>>> +	base_subchannel_ptr = path_channel +
>>>> +		(base_subchannel_name - subchannel_name);
>>>> +
>>>> +#ifdef HAS_INOTIFY
>>>> +	iwatch_array->elem = realloc(iwatch_array->elem,
>>>> +		++iwatch_array->num * sizeof(struct inotify_watch));
>>>> +
>>>> +	printf_verbose("Adding inotify for channel %s\n", path_channel);
>>>> +	iwatch_array->elem[iwatch_array->num-1].wd = inotify_add_watch(*inotify_fd, path_channel, IN_CREATE);
>>>> +	strcpy(iwatch_array->elem[iwatch_array->num-1].path_channel, path_channel);
>>>> +	iwatch_array->elem[iwatch_array->num-1].base_path_channel =
>>>> +		iwatch_array->elem[iwatch_array->num-1].path_channel +
>>>> +		(base_subchannel_name - subchannel_name);
>>>> +	printf_verbose("Added inotify for channel %s, wd %u\n",
>>>> +		iwatch_array->elem[iwatch_array->num-1].path_channel,
>>>> +		iwatch_array->elem[iwatch_array->num-1].wd);
>>>> +#endif
>>>> +
>>>> +	while((entry = readdir(channel_dir)) != NULL) {
>>>> +
>>>> +		if(entry->d_name[0] == '.') continue;
>>>> +
>>>> +		strncpy(path_channel_ptr, entry->d_name, PATH_MAX - path_channel_len);
>>>> +
>>>> +		ret = stat(path_channel,&stat_buf);
>>>> +		if(ret == -1) {
>>>> +			perror(path_channel);
>>>> +			continue;
>>>> +		}
>>>> +
>>>> +		printf_verbose("Channel file : %s\n", path_channel);
>>>> +
>>>> +		if(S_ISDIR(stat_buf.st_mode)) {
>>>> +
>>>> +			printf_verbose("Entering channel subdirectory...\n");
>>>> +			ret = open_channel_trace_pairs(path_channel, base_subchannel_ptr, fd_pairs,
>>>> +				inotify_fd, iwatch_array);
>>>> +			if(ret<  0) continue;
>>>> +		} else if(S_ISREG(stat_buf.st_mode)) {
>>>> +			open_ret = open_buffer_file(entry->d_name, path_channel, base_subchannel_ptr,
>>>> +				fd_pairs);
>>>> +			if(open_ret)
>>>> +				goto end;
>>>> +		}
>>>> +	}
>>>> +
>>>> +end:
>>>> +	closedir(channel_dir);
>>>> +
>>>> +	return open_ret;
>>>> +}
>>>> +
>>>> +
>>>> +int read_subbuffer(struct fd_pair *pair)
>>>> +{
>>>> +	unsigned int consumed_old, len;
>>>> +	int err;
>>>> +	long ret;
>>>> +	off_t offset;
>>>> +
>>>> +
>>>> +	err = ioctl(pair->channel, RELAY_GET_SB,&consumed_old);
>>>> +	printf_verbose("cookie : %u\n", consumed_old);
>>>> +	if(err != 0) {
>>>> +		ret = errno;
>>>> +		perror("Reserving sub buffer failed (everything is normal, it is due to concurrency)");
>>>> +		goto get_error;
>>>> +	}
>>>> +
>>>> +	err = ioctl(pair->channel, RELAY_GET_SB_SIZE,&len);
>>>> +	if(err != 0) {
>>>> +		ret = errno;
>>>> +		perror("Getting sub-buffer len failed.");
>>>> +		goto get_error;
>>>> +	}
>>>> +
>>>> +	if(callbacks->on_read_subbuffer) ret = callbacks->on_read_subbuffer(
>>>> +		callbacks, pair, len);
>>>> +
>>>> +write_error:
>>>> +	ret = 0;
>>>> +	err = ioctl(pair->channel, RELAY_PUT_SB,&consumed_old);
>>>> +	if(err != 0) {
>>>> +		ret = errno;
>>>> +		if(errno == EFAULT) {
>>>> +			perror("Error in unreserving sub buffer\n");
>>>> +		} else if(errno == EIO) {
>>>> +			/* Should never happen with newer LTTng versions */
>>>> +			perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
>>>> +		}
>>>> +		goto get_error;
>>>> +	}
>>>> +
>>>> +get_error:
>>>> +	return ret;
>>>> +}
>>>> +
>>>> +
>>>> +int map_channels(struct channel_trace_fd *fd_pairs,
>>>> +	int idx_begin, int idx_end)
>>>> +{
>>>> +	int i,j;
>>>> +	int ret=0;
>>>> +
>>>> +	if(fd_pairs->num_pairs<= 0) {
>>>> +		printf("No channel to read\n");
>>>> +		goto end;
>>>> +	}
>>>> +
>>>> +	/* Get the subbuf sizes and number */
>>>> +
>>>> +	for(i=idx_begin;i<idx_end;i++) {
>>>> +		struct fd_pair *pair =&fd_pairs->pair[i];
>>>> +
>>>> +		ret = ioctl(pair->channel, RELAY_GET_N_SB,&pair->n_sb);
>>>> +		if(ret != 0) {
>>>> +			perror("Error in getting the number of sub-buffers");
>>>> +			goto end;
>>>> +		}
>>>> +		ret = ioctl(pair->channel, RELAY_GET_MAX_SB_SIZE,
>>>> +			&pair->max_sb_size);
>>>> +		if(ret != 0) {
>>>> +			perror("Error in getting the max sub-buffer size");
>>>> +			goto end;
>>>> +		}
>>>> +		ret = pthread_mutex_init(&pair->mutex, NULL);	/* Fast mutex */
>>>> +		if(ret != 0) {
>>>> +			perror("Error in mutex init");
>>>> +			goto end;
>>>> +		}
>>>> +	}
>>>> +
>>>> +end:
>>>> +	return ret;
>>>> +}
>>>> +
>>>> +int unmap_channels(struct channel_trace_fd *fd_pairs)
>>>> +{
>>>> +	int j;
>>>> +	int ret=0;
>>>> +
>>>> +	/* Munmap each FD */
>>>> +	for(j=0;j<fd_pairs->num_pairs;j++) {
>>>> +		struct fd_pair *pair =&fd_pairs->pair[j];
>>>> +		int err_ret;
>>>> +
>>>> +		err_ret = pthread_mutex_destroy(&pair->mutex);
>>>> +		if(err_ret != 0) {
>>>> +			perror("Error in mutex destroy");
>>>> +		}
>>>> +		ret |= err_ret;
>>>> +	}
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +
>>>> +#ifdef HAS_INOTIFY
>>>> +/* Inotify event arrived.
>>>> + *
>>>> + * Only support add file for now.
>>>> + */
>>>> +
>>>> +int read_inotify(int inotify_fd,
>>>> +	struct channel_trace_fd *fd_pairs,
>>>> +	struct inotify_watch_array *iwatch_array)
>>>> +{
>>>> +	char buf[sizeof(struct inotify_event) + PATH_MAX];
>>>> +	char path_channel[PATH_MAX];
>>>> +	ssize_t len;
>>>> +	struct inotify_event *ievent;
>>>> +	size_t offset;
>>>> +	unsigned int i;
>>>> +	int ret;
>>>> +	int old_num;
>>>> +
>>>> +	offset = 0;
>>>> +	len = read(inotify_fd, buf, sizeof(struct inotify_event) + PATH_MAX);
>>>> +	if(len<  0) {
>>>> +
>>>> +		if(errno == EAGAIN)
>>>> +			return 0;  /* another thread got the data before us */
>>>> +
>>>> +		printf("Error in read from inotify FD %s.\n", strerror(len));
>>>> +		return -1;
>>>> +	}
>>>> +	while(offset<  len) {
>>>> +		ievent = (struct inotify_event *)&(buf[offset]);
>>>> +		for(i=0; i<iwatch_array->num; i++) {
>>>> +			if(iwatch_array->elem[i].wd == ievent->wd&&
>>>> +				ievent->mask == IN_CREATE) {
>>>> +				printf_verbose(
>>>> +					"inotify wd %u event mask : %u for %s%s\n",
>>>> +					ievent->wd, ievent->mask,
>>>> +					iwatch_array->elem[i].path_channel,
>>>> +					ievent->name);
>>>> +				old_num = fd_pairs->num_pairs;
>>>> +				strcpy(path_channel, iwatch_array->elem[i].path_channel);
>>>> +				strcat(path_channel, ievent->name);
>>>> +				if(ret = open_buffer_file(ievent->name, path_channel,
>>>> +					path_channel + (iwatch_array->elem[i].base_path_channel -
>>>> +					iwatch_array->elem[i].path_channel), fd_pairs)) {
>>>> +					printf("Error opening buffer file\n");
>>>> +					return -1;
>>>> +				}
>>>> +				if(ret = map_channels(fd_pairs, old_num, fd_pairs->num_pairs)) {
>>>> +					printf("Error mapping channel\n");
>>>> +					return -1;
>>>> +				}
>>>> +
>>>> +			}
>>>> +		}
>>>> +		offset += sizeof(*ievent) + ievent->len;
>>>> +	}
>>>> +}
>>>> +#endif //HAS_INOTIFY
>>>> +
>>>> +/* read_channels
>>>> + *
>>>> + * Thread worker.
>>>> + *
>>>> + * Read the debugfs channels and write them in the paired tracefiles.
>>>> + *
>>>> + * @fd_pairs : paired channels and trace files.
>>>> + *
>>>> + * returns 0 on success, -1 on error.
>>>> + *
>>>> + * Note that the high priority polled channels are consumed first. We then poll
>>>> + * again to see if these channels are still in priority. Only when no
>>>> + * high priority channel is left, we start reading low priority channels.
>>>> + *
>>>> + * Note that a channel is considered high priority when the buffer is almost
>>>> + * full.
>>>> + */
>>>> +
>>>> +int read_channels(unsigned long thread_num, struct channel_trace_fd *fd_pairs,
>>>> +	int inotify_fd, struct inotify_watch_array *iwatch_array)
>>>> +{
>>>> +	struct pollfd *pollfd = NULL;
>>>> +	int num_pollfd;
>>>> +	int i,j;
>>>> +	int num_rdy, num_hup;
>>>> +	int high_prio;
>>>> +	int ret = 0;
>>>> +	int inotify_fds;
>>>> +	unsigned int old_num;
>>>> +
>>>> +#ifdef HAS_INOTIFY
>>>> +	inotify_fds = 1;
>>>> +#else
>>>> +	inotify_fds = 0;
>>>> +#endif
>>>> +
>>>> +	pthread_rwlock_rdlock(&fd_pairs_lock);
>>>> +
>>>> +	/* Start polling the FD. Keep one fd for inotify */
>>>> +	pollfd = malloc((inotify_fds + fd_pairs->num_pairs) * sizeof(struct pollfd));
>>>> +
>>>> +#ifdef HAS_INOTIFY
>>>> +	pollfd[0].fd = inotify_fd;
>>>> +	pollfd[0].events = POLLIN|POLLPRI;
>>>> +#endif
>>>> +
>>>> +	for(i=0;i<fd_pairs->num_pairs;i++) {
>>>> +		pollfd[inotify_fds+i].fd = fd_pairs->pair[i].channel;
>>>> +		pollfd[inotify_fds+i].events = POLLIN|POLLPRI;
>>>> +	}
>>>> +	num_pollfd = inotify_fds + fd_pairs->num_pairs;
>>>> +
>>>> +
>>>> +	pthread_rwlock_unlock(&fd_pairs_lock);
>>>> +
>>>> +	while(1) {
>>>> +		high_prio = 0;
>>>> +		num_hup = 0;
>>>> +#ifdef DEBUG
>>>> +		printf("Press a key for next poll...\n");
>>>> +		char buf[1];
>>>> +		read(STDIN_FILENO,&buf, 1);
>>>> +		printf("Next poll (polling %d fd) :\n", num_pollfd);
>>>> +#endif //DEBUG
>>>> +
>>>> +		/* Have we received a signal ? */
>>>> +		if(quit_program) break;
>>>> +
>>>> +		num_rdy = poll(pollfd, num_pollfd, -1);
>>>> +
>>>> +		if(num_rdy == -1) {
>>>> +			perror("Poll error");
>>>> +			goto free_fd;
>>>> +		}
>>>> +
>>>> +		printf_verbose("Data received\n");
>>>> +#ifdef HAS_INOTIFY
>>>> +		switch(pollfd[0].revents) {
>>>> +			case POLLERR:
>>>> +				printf_verbose(
>>>> +					"Error returned in polling inotify fd %d.\n",
>>>> +					pollfd[0].fd);
>>>> +				break;
>>>> +			case POLLHUP:
>>>> +				printf_verbose(
>>>> +					"Polling inotify fd %d tells it has hung up.\n",
>>>> +					pollfd[0].fd);
>>>> +				break;
>>>> +			case POLLNVAL:
>>>> +				printf_verbose(
>>>> +					"Polling inotify fd %d tells fd is not open.\n",
>>>> +					pollfd[0].fd);
>>>> +				break;
>>>> +			case POLLPRI:
>>>> +			case POLLIN:
>>>> +				printf_verbose(
>>>> +					"Polling inotify fd %d : data ready.\n",
>>>> +					pollfd[0].fd);
>>>> +
>>>> +				pthread_rwlock_wrlock(&fd_pairs_lock);
>>>> +				read_inotify(inotify_fd, fd_pairs, iwatch_array);
>>>> +				pthread_rwlock_unlock(&fd_pairs_lock);
>>>> +
>>>> +			break;
>>>> +		}
>>>> +#endif
>>>> +
>>>> +		for(i=inotify_fds;i<num_pollfd;i++) {
>>>> +			switch(pollfd[i].revents) {
>>>> +				case POLLERR:
>>>> +					printf_verbose(
>>>> +						"Error returned in polling fd %d.\n",
>>>> +						pollfd[i].fd);
>>>> +					num_hup++;
>>>> +					break;
>>>> +				case POLLHUP:
>>>> +					printf_verbose(
>>>> +						"Polling fd %d tells it has hung up.\n",
>>>> +						pollfd[i].fd);
>>>> +					num_hup++;
>>>> +					break;
>>>> +				case POLLNVAL:
>>>> +					printf_verbose(
>>>> +						"Polling fd %d tells fd is not open.\n",
>>>> +						pollfd[i].fd);
>>>> +					num_hup++;
>>>> +					break;
>>>> +				case POLLPRI:
>>>> +					pthread_rwlock_rdlock(&fd_pairs_lock);
>>>> +					if(pthread_mutex_trylock(&fd_pairs->pair[i-inotify_fds].mutex) == 0) {
>>>> +						printf_verbose(
>>>> +							"Urgent read on fd %d\n",
>>>> +							pollfd[i].fd);
>>>> +						/* Take care of high priority channels first. */
>>>> +						high_prio = 1;
>>>> +						/* it's ok to have an unavailable sub-buffer */
>>>> +						ret = read_subbuffer(&fd_pairs->pair[i-inotify_fds]);
>>>> +						if(ret == EAGAIN) ret = 0;
>>>> +
>>>> +						ret = pthread_mutex_unlock(&fd_pairs->pair[i-inotify_fds].mutex);
>>>> +						if(ret)
>>>> +							printf("Error in mutex unlock : %s\n", strerror(ret));
>>>> +					}
>>>> +					pthread_rwlock_unlock(&fd_pairs_lock);
>>>> +					break;
>>>> +			}
>>>> +		}
>>>> +		/* If every buffer FD has hung up, we end the read loop here */
>>>> +		if(num_hup == num_pollfd - inotify_fds) break;
>>>> +
>>>> +		if(!high_prio) {
>>>> +			for(i=inotify_fds;i<num_pollfd;i++) {
>>>> +				switch(pollfd[i].revents) {
>>>> +					case POLLIN:
>>>> +						pthread_rwlock_rdlock(&fd_pairs_lock);
>>>> +						if(pthread_mutex_trylock(&fd_pairs->pair[i-inotify_fds].mutex) == 0) {
>>>> +							/* Take care of low priority channels. */
>>>> +							printf_verbose(
>>>> +								"Normal read on fd %d\n",
>>>> +								pollfd[i].fd);
>>>> +							/* it's ok to have an unavailable subbuffer */
>>>> +							ret = read_subbuffer(&fd_pairs->pair[i-inotify_fds]);
>>>> +							if(ret == EAGAIN) ret = 0;
>>>> +
>>>> +							ret = pthread_mutex_unlock(&fd_pairs->pair[i-inotify_fds].mutex);
>>>> +							if(ret)
>>>> +								printf("Error in mutex unlock : %s\n", strerror(ret));
>>>> +						}
>>>> +						pthread_rwlock_unlock(&fd_pairs_lock);
>>>> +						break;
>>>> +				}
>>>> +			}
>>>> +		}
>>>> +
>>>> +		/* Update pollfd array if an entry was added to fd_pairs */
>>>> +		pthread_rwlock_rdlock(&fd_pairs_lock);
>>>> +		if((inotify_fds + fd_pairs->num_pairs) != num_pollfd) {
>>>> +			pollfd = realloc(pollfd,
>>>> +					(inotify_fds + fd_pairs->num_pairs) * sizeof(struct pollfd));
>>>> +			for(i=num_pollfd-inotify_fds;i<fd_pairs->num_pairs;i++) {
>>>> +				pollfd[inotify_fds+i].fd = fd_pairs->pair[i].channel;
>>>> +				pollfd[inotify_fds+i].events = POLLIN|POLLPRI;
>>>> +			}
>>>> +			num_pollfd = fd_pairs->num_pairs + inotify_fds;
>>>> +		}
>>>> +		pthread_rwlock_unlock(&fd_pairs_lock);
>>>> +
>>>> +		/* NB: If the fd_pairs structure is updated by another thread from this
>>>> +		 *     point forward, the current thread will wait in the poll without
>>>> +		 *     monitoring the new channel. However, this thread will add the
>>>> +		 *     new channel on next poll (and this should not take too much time
>>>> +		 *     on a loaded system).
>>>> +		 *
>>>> +		 *     This event is quite unlikely and can only occur if a CPU is
>>>> +		 *     hot-plugged while multple lttd threads are running.
>>>> +		 */
>>>> +	}
>>>> +
>>>> +free_fd:
>>>> +	free(pollfd);
>>>> +
>>>> +end:
>>>> +	return ret;
>>>> +}
>>>> +
>>>> +
>>>> +void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs, int inotify_fd,
>>>> +	struct inotify_watch_array *iwatch_array)
>>>> +{
>>>> +	int i;
>>>> +	int ret;
>>>> +
>>>> +	for(i=0;i<fd_pairs->num_pairs;i++) {
>>>> +		ret = close(fd_pairs->pair[i].channel);
>>>> +		if(ret == -1) perror("Close error on channel");
>>>> +		if(callbacks->on_close_channel) {
>>>> +			ret = callbacks->on_close_channel(
>>>> +				callbacks,&fd_pairs->pair[i]);
>>>> +			if(ret != 0) perror("Error on close channel callback");
>>>> +		}
>>>> +	}
>>>> +	free(fd_pairs->pair);
>>>> +	free(iwatch_array->elem);
>>>> +}
>>>> +
>>>> +/* Thread worker */
>>>> +void * thread_main(void *arg)
>>>> +{
>>>> +	long ret = 0;
>>>> +	unsigned long thread_num = (unsigned long)arg;
>>>> +
>>>> +	if(callbacks->on_new_thread)
>>>> +		ret = callbacks->on_new_thread(callbacks, thread_num);
>>>> +
>>>> +	if (ret<  0) {
>>>> +		return (void*)ret;
>>>> +	}
>>>> +	ret = read_channels(thread_num,&fd_pairs, inotify_fd,&inotify_watch_array);
>>>> +
>>>> +	if(callbacks->on_close_thread)
>>>> +		callbacks->on_close_thread(callbacks, thread_num);
>>>> +
>>>> +	return (void*)ret;
>>>> +}
>>>> +
>>>> +/*on_close_thread has to be reentrant, it'll be called by many threads*/
>>>> +int(*on_close_thread)(struct liblttd_callbacks *data, unsigned long thread_num);
>>>> +
>>>> +int channels_init()
>>>> +{
>>>> +	int ret = 0;
>>>> +
>>>> +	inotify_fd = inotify_init();
>>>> +	fcntl(inotify_fd, F_SETFL, O_NONBLOCK);
>>>> +
>>>> +	if(ret = open_channel_trace_pairs(channel_name,
>>>> +			channel_name + strlen(channel_name),&fd_pairs,
>>>> +			&inotify_fd,&inotify_watch_array))
>>>> +		goto close_channel;
>>>> +	if (fd_pairs.num_pairs == 0) {
>>>> +		printf("No channel available for reading, exiting\n");
>>>> +		ret = -ENOENT;
>>>> +		goto close_channel;
>>>> +	}
>>>> +	if(ret = map_channels(&fd_pairs, 0, fd_pairs.num_pairs))
>>>> +		goto close_channel;
>>>> +	return 0;
>>>> +
>>>> +close_channel:
>>>> +	close_channel_trace_pairs(&fd_pairs, inotify_fd,&inotify_watch_array);
>>>> +	if(inotify_fd>= 0)
>>>> +		close(inotify_fd);
>>>> +	return ret;
>>>> +}
>>>> +
>>>> +int liblttd_start(char *channel_path, unsigned long n_threads,
>>>> +		int flight_only, int normal_only, int verbose,
>>>> +		struct liblttd_callbacks *user_data){
>>>> +	int ret = 0;
>>>> +	pthread_t *tids;
>>>> +	unsigned long i;
>>>> +	void *tret;
>>>> +
>>>> +	channel_name = channel_path;
>>>> +	num_threads = n_threads;
>>>> +	dump_flight_only = flight_only;
>>>> +	dump_normal_only = normal_only;
>>>> +	verbose_mode = verbose;
>>>> +	callbacks = user_data;
>>>> +
>>>> +	if(ret = channels_init())
>>>> +		return ret;
>>>> +
>>>> +	tids = malloc(sizeof(pthread_t) * num_threads);
>>>> +	for(i=0; i<num_threads; i++) {
>>>> +
>>>> +		ret = pthread_create(&tids[i], NULL, thread_main, (void*)i);
>>>> +		if(ret) {
>>>> +			perror("Error creating thread");
>>>> +			break;
>>>> +		}
>>>> +	}
>>>> +
>>>> +	for(i=0; i<num_threads; i++) {
>>>> +		ret = pthread_join(tids[i],&tret);
>>>> +		if(ret) {
>>>> +			perror("Error joining thread");
>>>> +			break;
>>>> +		}
>>>> +		if((long)tret != 0) {
>>>> +			printf("Error %s occured in thread %ld\n",
>>>> +				strerror((long)tret), i);
>>>> +		}
>>>> +	}
>>>> +
>>>> +	free(tids);
>>>> +	ret = unmap_channels(&fd_pairs);
>>>> +	close_channel_trace_pairs(&fd_pairs, inotify_fd,&inotify_watch_array);
>>>> +	if(inotify_fd>= 0)
>>>> +		close(inotify_fd);
>>>> +
>>>> +	if(callbacks->on_trace_end) callbacks->on_trace_end(callbacks);
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +
>>>> +int liblttd_stop() {
>>>> +	quit_program = 1;
>>>> +	return 0;
>>>> +}
>>>> +
>>>> diff --git a/liblttd/liblttd.h b/liblttd/liblttd.h
>>>> new file mode 100644
>>>> index 0000000..bd76eeb
>>>> --- /dev/null
>>>> +++ b/liblttd/liblttd.h
>>>> @@ -0,0 +1,218 @@
>>>> +/* liblttd header file
>>>> + *
>>>> + * Copyright 2010-
>>>> + *		 Oumarou Dicko<oumarou.dicko at polymtl.ca>
>>>> + *		 Michael Sills-Lavoie<michael.sills-lavoie at polymtl.ca>
>>>> + *
>>>> + *
>>>> + * This program is free software; you can redistribute it and/or modify
>>>> + * it under the terms of the GNU General Public License as published by
>>>> + * the Free Software Foundation; either version 2 of the License, or
>>>> + * (at your option) any later version.
>>>> + *
>>>> + * This program is distributed in the hope that it will be useful,
>>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the
>>>> + * GNU General Public License for more details.
>>>> + *
>>>> + */
>>>> +
>>>> +#ifndef _LIBLTTD_H
>>>> +#define _LIBLTTD_H
>>>> +
>>>> +#include<pthread.h>
>>>> +
>>>> +/**
>>>> +* This structure contains the data associated with the channel file descriptor.
>>>> +* The lib user can use user_data to store the data associated to the specified
>>>> +* channel. The lib user can read but MUST NOT change the other attributes.
>>>> +*/
>>>> +struct fd_pair {
>>>> +	/**
>>>> +	* This is the channel file descriptor.
>>>> +	*/
>>>> +	int channel;
>>>> +
>>>> +	/**
>>>> +	* This is the number of subbuffer for this channel.
>>>> +	*/
>>>> +	unsigned int n_sb;
>>>> +
>>>> +	/**
>>>> +	* This is the subbuffer size for this channel.
>>>> +	*/
>>>> +	unsigned int max_sb_size;
>>>> +
>>>> +	/**
>>>> +	* Not used anymore.
>>>> +	*/
>>>> +	void *mmap;
>>>> +
>>>> +	/**
>>>> +	* This is a mutex for internal library usage.
>>>> +	*/
>>>> +	pthread_mutex_t	mutex;
>>>> +
>>>> +	/**
>>>> +	* Library user data.
>>>> +	*/
>>>> +	void *user_data;
>>>> +};
>>>> +
>>>> +/**
>>>> +* This structure contains the necessary callbacks for a tracing session. The
>>>> +* user can set the unnecessary functions to NULL if he does not need them.
>>>> +*/
>>>> +struct liblttd_callbacks {
>>>> +	/**
>>>> +	* This callback is called after a channel file is open.
>>>> +	*
>>>> +	* @args data This argument is a pointeur to the callbacks struct that
>>>> +	*            has been passed to the lib.
>>>> +	* @args pair This structure contains the data associated with the
>>>> +	*            channel file descriptor. The lib user can use user_data to
>>>> +	*            store the data associated to the specified channel.
>>>> +	* @args relative_channel_path This argument represents a relative path
>>>> +	*            to the channel file. This path is relative to the root
>>>> +	*            folder of the trace channels.
>>>> +	*
>>>> +	* @return Should return 0 if the callback succeeds else not 0.
>>>> +	*/
>>>> +	int(*on_open_channel)(struct liblttd_callbacks *data,
>>>> +		struct fd_pair *pair, char *relative_channel_path);
>>>> +
>>>> +	/**
>>>> +	* This callback is called after a channel file is closed.
>>>> +	*
>>>> +	* @remarks After a channel file has been closed, it will never be read
>>>> +	*            again.
>>>> +	*
>>>> +	* @args data This argument is a pointeur to the callbacks struct that
>>>> +	*            has been passed to the lib.
>>>> +	* @args pair This structure contains the data associated with the
>>>> +	*            channel file descriptor. The lib user should clean
>>>> +	*            user_data at this time.
>>>> +	*
>>>> +	* @return Should return 0 if the callback succeeds else not 0.
>>>> +	*/
>>>> +	int(*on_close_channel)(struct liblttd_callbacks *data,
>>>> +		struct fd_pair *pair);
>>>> +
>>>> +
>>>> +	/**
>>>> +	* This callback is called when the library enter in a new subfolder
>>>> +	* while it is scanning the trace channel tree. It can be used to create
>>>> +	* the output file structure of the trace.
>>>> +	*
>>>> +	* @args data This argument is a pointeur to the callbacks struct that
>>>> +	*            has been passed to the lib.
>>>> +	* @args relative_folder_path This argument represents a relative path
>>>> +	*            to the channel folder. This path is relative to the root
>>>> +	*            folder of the trace channels.
>>>> +	*
>>>> +	* @return Should return 0 if the callback succeeds else not 0.
>>>> +	*/
>>>> +	int(*on_new_channels_folder)(struct liblttd_callbacks *data,
>>>> +		char *relative_folder_path);
>>>> +
>>>> +	/**
>>>> +	* This callback is called after a subbuffer is a reserved.
>>>> +	*
>>>> +	* @attention It has to be thread safe, it'll be called by many threads.
>>>> +	*
>>>> +	* @args data This argument is a pointeur to the callbacks struct that
>>>> +	*            has been passed to the lib.
>>>> +	* @args pair This structure contains the data associated with the
>>>> +	*            channel file descriptor. The lib user should clean
>>>> +	*            user_data at this time.
>>>> +	* @args len This argument represents the length the data that has to be
>>>> +	*            read.
>>>> +	*
>>>> +	* @return Should return 0 if the callback succeeds else not 0.
>>>> +	*/
>>>> +	int(*on_read_subbuffer)(struct liblttd_callbacks *data,
>>>> +		struct fd_pair *pair, unsigned int len);
>>>> +
>>>> +	/**
>>>> +	* This callback is called at the very end of the tracing session. At
>>>> +	* this time, all the channels have been closed and the threads have been
>>>> +	* destroyed.
>>>> +	*
>>>> +	* @remarks After this callback is called, no other callback will be
>>>> +	*            called again.
>>>> +	*
>>>> +	* @attention It has to be thread safe, it'll be called by many threads.
>>>> +	*
>>>> +	* @args data This argument is a pointeur to the callbacks struct that
>>>> +	*            has been passed to the lib.
>>>> +	*
>>>> +	* @return Should return 0 if the callback succeeds else not 0.
>>>> +	*/
>>>> +	int(*on_trace_end)(struct liblttd_callbacks *data);
>>>> +
>>>> +	/**
>>>> +	* This callback is called after a new thread has been created.
>>>> +	*
>>>> +	* @attention It has to be thread safe, it'll be called by many threads.
>>>> +	*
>>>> +	* @args data This argument is a pointeur to the callbacks struct that
>>>> +	*            has been passed to the lib.
>>>> +	* @args thread_num This argument represents the id of the thread.
>>>> +	*
>>>> +	* @return Should return 0 if the callback succeeds else not 0.
>>>> +	*/
>>>> +	int(*on_new_thread)(struct liblttd_callbacks *data,
>>>> +		unsigned long thread_num);
>>>> +
>>>> +	/**
>>>> +	* This callback is called just before a thread is destroyed.
>>>> +	*
>>>> +	* @attention It has to be thread safe, it'll be called by many threads.
>>>> +	*
>>>> +	* @args data This argument is a pointeur to the callbacks struct that
>>>> +	*            has been passed to the lib.
>>>> +	* @args thread_num This argument represents the number of the thread.
>>>> +	*
>>>> +	* @return Should return 0 if the callback succeeds else not 0.
>>>> +	*/
>>>> +	int(*on_close_thread)(struct liblttd_callbacks *data,
>>>> +		unsigned long thread_num);
>>>> +
>>>> +	/**
>>>> +	* This is where the user can put the library's data.
>>>> +	*/
>>>> +	void *user_data;
>>>> +};
>>>> +
>>>> +/**
>>>> +* This function is called to start a new tracing session.
>>>> +*
>>>> +* @attention It has to be thread safe, it'll be called by many threads.
>>>> +*
>>>> +* @args channel_path This argument is a path to the root folder of the trace's
>>>> +*            channels.
>>>> +* @args n_threads This argument represents the number of threads that will be
>>>> +*            used by the library.
>>>> +* @args flight_only If this argument to set to 1, only the channel that are in
>>>> +*            flight recorder mode will be recorded.
>>>> +* @args normal_only If this argument to set to 1, only the channel that are in
>>>> +*            normal mode will be recorded.
>>>> +* @args verbose If this argument to set to 1, more informations will be printed.
>>>> +* @args user_data This argument is a pointeur to the callbacks struct that
>>>> +*            contains the user's functions.
>>>> +*
>>>> +* @return Return 0 if the function succeeds else not 0.
>>>> +*/
>>>> +int liblttd_start(char *channel_path, unsigned long n_threads,
>>>> +	int flight_only, int normal_only, int verbose,
>>>> +	struct liblttd_callbacks *user_data);
>>>> +
>>>> +/**
>>>> +* This function is called to stop a tracing session.
>>>> +*
>>>> +* @return Return 0 if the function succeeds.
>>>> +*/
>>>> +int liblttd_stop();
>>>> +
>>>> +#endif /*_LIBLTTD_H */
>>>> +
>>>> diff --git a/lttd/Makefile.am b/lttd/Makefile.am
>>>> index bb860bc..fc9b219 100644
>>>> --- a/lttd/Makefile.am
>>>> +++ b/lttd/Makefile.am
>>>> @@ -6,3 +6,6 @@ bin_PROGRAMS = lttd
>>>>
>>>>   lttd_SOURCES = lttd.c
>>>>
>>>> +lttd_DEPENDENCIES = ../liblttd/liblttd.la
>>>> +lttd_LDADD = $(lttd_DEPENDENCIES)
>>>> +
>>>> diff --git a/lttd/lttd.c b/lttd/lttd.c
>>>> index 78c2c80..ec757ae 100644
>>>> --- a/lttd/lttd.c
>>>> +++ b/lttd/lttd.c
>>>> @@ -30,125 +30,36 @@
>>>>
>>>>   #define _REENTRANT
>>>>   #define _GNU_SOURCE
>>>> -#include<features.h>
>>>> +
>>>>   #include<stdio.h>
>>>> -#include<unistd.h>
>>>> -#include<errno.h>
>>>> -#include<sys/types.h>
>>>> -#include<sys/stat.h>
>>>>   #include<stdlib.h>
>>>> -#include<dirent.h>
>>>>   #include<string.h>
>>>> -#include<fcntl.h>
>>>> -#include<sys/poll.h>
>>>> -#include<sys/mman.h>
>>>>   #include<signal.h>
>>>> -#include<pthread.h>
>>>> -#include<sys/syscall.h>
>>>> -#include<unistd.h>
>>>> -#include<asm/ioctls.h>
>>>> -
>>>> -#include<linux/version.h>
>>>> -
>>>> -/* Relayfs IOCTL */
>>>> -#include<asm/ioctl.h>
>>>> -#include<asm/types.h>
>>>> -
>>>> -/* Get the next sub buffer that can be read. */
>>>> -#define RELAY_GET_SB		_IOR(0xF5, 0x00,__u32)
>>>> -/* Release the oldest reserved (by "get") sub buffer. */
>>>> -#define RELAY_PUT_SB		_IOW(0xF5, 0x01,__u32)
>>>> -/* returns the number of sub buffers in the per cpu channel. */
>>>> -#define RELAY_GET_N_SB		_IOR(0xF5, 0x02,__u32)
>>>> -/* returns the size of the current sub buffer. */
>>>> -#define RELAY_GET_SB_SIZE	_IOR(0xF5, 0x03, __u32)
>>>> -/* returns the size of data to consume in the current sub-buffer. */
>>>> -#define RELAY_GET_MAX_SB_SIZE	_IOR(0xF5, 0x04, __u32)
>>>> -
>>>> -
>>>> -#if LINUX_VERSION_CODE>= KERNEL_VERSION(2,6,14)
>>>> -#include<sys/inotify.h>
>>>> -#if 0	/* should now be provided by libc. */
>>>> -/* From the inotify-tools 2.6 package */
>>>> -static inline int inotify_init (void)
>>>> -{
>>>> -	return syscall (__NR_inotify_init);
>>>> -}
>>>> -
>>>> -static inline int inotify_add_watch (int fd, const char *name, __u32 mask)
>>>> -{
>>>> -	return syscall (__NR_inotify_add_watch, fd, name, mask);
>>>> -}
>>>> -
>>>> -static inline int inotify_rm_watch (int fd, __u32 wd)
>>>> -{
>>>> -	return syscall (__NR_inotify_rm_watch, fd, wd);
>>>> -}
>>>> -#endif //0
>>>> -#define HAS_INOTIFY
>>>> -#else
>>>> -static inline int inotify_init (void)
>>>> -{
>>>> -	return -1;
>>>> -}
>>>> +#include<errno.h>
>>>> +#include<fcntl.h>
>>>> +#include<dirent.h>
>>>> +#include<sys/stat.h>
>>>>
>>>> -static inline int inotify_add_watch (int fd, const char *name, __u32 mask)
>>>> -{
>>>> -	return 0;
>>>> -}
>>>> +#include<liblttd/liblttd.h>
>>>>
>>>> -static inline int inotify_rm_watch (int fd, __u32 wd)
>>>> -{
>>>> -	return 0;
>>>> -}
>>>> -#undef HAS_INOTIFY
>>>> -#endif
>>>> -
>>>> -struct fd_pair {
>>>> -	int channel;
>>>> +struct lttd_channel_data {
>>>>   	int trace;
>>>> -	unsigned int n_sb;
>>>> -	unsigned int max_sb_size;
>>>> -	void *mmap;
>>>> -	pthread_mutex_t	mutex;
>>>> -};
>>>> -
>>>> -struct channel_trace_fd {
>>>> -	struct fd_pair *pair;
>>>> -	int num_pairs;
>>>> -};
>>>> -
>>>> -struct inotify_watch {
>>>> -	int wd;
>>>> -	char path_channel[PATH_MAX];
>>>> -	char path_trace[PATH_MAX];
>>>> -};
>>>> -
>>>> -struct inotify_watch_array {
>>>> -	struct inotify_watch *elem;
>>>> -	int num;
>>>>   };
>>>>
>>>> -static __thread int thread_pipe[2];
>>>> -
>>>> -struct channel_trace_fd fd_pairs = { NULL, 0 };
>>>> -int inotify_fd = -1;
>>>> -struct inotify_watch_array inotify_watch_array = { NULL, 0 };
>>>> -
>>>> -/* protects fd_pairs and inotify_watch_array */
>>>> -pthread_rwlock_t fd_pairs_lock = PTHREAD_RWLOCK_INITIALIZER;
>>>> -
>>>> -
>>>> +static char		path_trace[PATH_MAX];
>>>> +static char		*end_path_trace;
>>>> +static int		path_trace_len = 0;
>>>>   static char		*trace_name = NULL;
>>>>   static char		*channel_name = NULL;
>>>>   static int		daemon_mode = 0;
>>>>   static int		append_mode = 0;
>>>>   static unsigned long	num_threads = 1;
>>>> -volatile static int	quit_program = 0;	/* For signal handler */
>>>>   static int		dump_flight_only = 0;
>>>>   static int		dump_normal_only = 0;
>>>>   static int		verbose_mode = 0;
>>>>
>>>> +static __thread int thread_pipe[2];
>>>> +
>>>>   #define printf_verbose(fmt, args...) \
>>>>     do {                               \
>>>>       if (verbose_mode)                \
>>>> @@ -191,7 +102,7 @@ int parse_arguments(int argc, char **argv)
>>>>   {
>>>>   	int ret = 0;
>>>>   	int argn = 1;
>>>> -	
>>>> +
>>>>   	if(argc == 2) {
>>>>   		if(strcmp(argv[1], "-h") == 0) {
>>>>   			return 1;
>>>> @@ -249,19 +160,19 @@ int parse_arguments(int argc, char **argv)
>>>>   		}
>>>>   		argn++;
>>>>   	}
>>>> -	
>>>> +
>>>>   	if(trace_name == NULL) {
>>>>   		printf("Please specify a trace name.\n");
>>>>   		printf("\n");
>>>>   		ret = -1;
>>>>   	}
>>>> -	
>>>> +
>>>>   	if(channel_name == NULL) {
>>>>   		printf("Please specify a channel name.\n");
>>>>   		printf("\n");
>>>>   		ret = -1;
>>>>   	}
>>>> -	
>>>> +
>>>>   	return ret;
>>>>   }
>>>>
>>>> @@ -280,223 +191,96 @@ void show_info(void)
>>>>   static void handler(int signo)
>>>>   {
>>>>   	printf("Signal %d received : exiting cleanly\n", signo);
>>>> -	quit_program = 1;
>>>> +	liblttd_stop();
>>>>   }
>>>>
>>>> -
>>>> -int open_buffer_file(char *filename, char *path_channel, char *path_trace,
>>>> -	struct channel_trace_fd *fd_pairs)
>>>> +int lttd_on_open_channel(struct liblttd_callbacks *data, struct fd_pair *pair, char *relative_channel_path)
>>>>   {
>>>>   	int open_ret = 0;
>>>> -	int ret = 0;
>>>> +	int ret;
>>>>   	struct stat stat_buf;
>>>> +	struct lttd_channel_data *channel_data;
>>>>
>>>> -	if(strncmp(filename, "flight-", sizeof("flight-")-1) != 0) {
>>>> -		if(dump_flight_only) {
>>>> -			printf_verbose("Skipping normal channel %s\n",
>>>> -				path_channel);
>>>> -			return 0;
>>>> -		}
>>>> -	} else {
>>>> -		if(dump_normal_only) {
>>>> -			printf_verbose("Skipping flight channel %s\n",
>>>> -				path_channel);
>>>> -			return 0;
>>>> -		}
>>>> -	}
>>>> -	printf_verbose("Opening file.\n");
>>>> -	
>>>> -	fd_pairs->pair = realloc(fd_pairs->pair,
>>>> -			++fd_pairs->num_pairs * sizeof(struct fd_pair));
>>>> +	pair->user_data = malloc(sizeof(struct lttd_channel_data));
>>>> +	channel_data = pair->user_data;
>>>> +
>>>> +	strncpy(end_path_trace, relative_channel_path, PATH_MAX - path_trace_len);
>>>> +	printf_verbose("Creating trace file %s\n", path_trace);
>>>>
>>>> -	/* Open the channel in read mode */
>>>> -	fd_pairs->pair[fd_pairs->num_pairs-1].channel =
>>>> -		open(path_channel, O_RDONLY | O_NONBLOCK);
>>>> -	if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) {
>>>> -		perror(path_channel);
>>>> -		fd_pairs->num_pairs--;
>>>> -		return 0;	/* continue */
>>>> -	}
>>>> -	/* Open the trace in write mode, only append if append_mode */
>>>>   	ret = stat(path_trace,&stat_buf);
>>>>   	if(ret == 0) {
>>>>   		if(append_mode) {
>>>>   			printf_verbose("Appending to file %s as requested\n",
>>>>   				path_trace);
>>>>
>>>> -			fd_pairs->pair[fd_pairs->num_pairs-1].trace =
>>>> -				open(path_trace, O_WRONLY,
>>>> -						S_IRWXU|S_IRWXG|S_IRWXO);
>>>> -			if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
>>>> +			channel_data->trace = open(path_trace, O_WRONLY, S_IRWXU|S_IRWXG|S_IRWXO);
>>>> +			if(channel_data->trace == -1) {
>>>>   				perror(path_trace);
>>>>   				open_ret = -1;
>>>> -				close(fd_pairs->pair[fd_pairs->num_pairs-1].channel);
>>>> -				fd_pairs->num_pairs--;
>>>>   				goto end;
>>>>   			}
>>>> -			ret = lseek(fd_pairs->pair[fd_pairs->num_pairs-1].trace,
>>>> -				    0, SEEK_END);
>>>> +			ret = lseek(channel_data->trace, 0, SEEK_END);
>>>>   			if (ret<  0) {
>>>>   				perror(path_trace);
>>>>   				open_ret = -1;
>>>> -				close(fd_pairs->pair[fd_pairs->num_pairs-1].channel);
>>>> -				close(fd_pairs->pair[fd_pairs->num_pairs-1].trace);
>>>> -				fd_pairs->num_pairs--;
>>>> +				close(channel_data->trace);
>>>>   				goto end;
>>>>   			}
>>>>   		} else {
>>>>   			printf("File %s exists, cannot open. Try append mode.\n", path_trace);
>>>>   			open_ret = -1;
>>>> -			close(fd_pairs->pair[fd_pairs->num_pairs-1].channel);
>>>> -			fd_pairs->num_pairs--;
>>>>   			goto end;
>>>>   		}
>>>>   	} else {
>>>>   		if(errno == ENOENT) {
>>>> -			fd_pairs->pair[fd_pairs->num_pairs-1].trace =
>>>> -				open(path_trace, O_WRONLY|O_CREAT|O_EXCL,
>>>> -						S_IRWXU|S_IRWXG|S_IRWXO);
>>>> -			if(fd_pairs->pair[fd_pairs->num_pairs-1].trace == -1) {
>>>> +			channel_data->trace = open(path_trace, O_WRONLY|O_CREAT|O_EXCL, S_IRWXU|S_IRWXG|S_IRWXO);
>>>> +			if(channel_data->trace == -1) {
>>>>   				perror(path_trace);
>>>>   				open_ret = -1;
>>>> -				close(fd_pairs->pair[fd_pairs->num_pairs-1].channel);
>>>> -				fd_pairs->num_pairs--;
>>>>   				goto end;
>>>>   			}
>>>>   		}
>>>>   	}
>>>> +
>>>>   end:
>>>>   	return open_ret;
>>>> +
>>>>   }
>>>>
>>>> -int open_channel_trace_pairs(char *subchannel_name, char *subtrace_name,
>>>> -		struct channel_trace_fd *fd_pairs, int *inotify_fd,
>>>> -		struct inotify_watch_array *iwatch_array)
>>>> +int lttd_on_close_channel(struct liblttd_callbacks *data, struct fd_pair *pair)
>>>> +{
>>>> +	int ret;
>>>> +	ret = close(((struct lttd_channel_data *)(pair->user_data))->trace);
>>>> +	free(pair->user_data);
>>>> +	return ret;
>>>> +}
>>>> +
>>>> +int lttd_on_new_channels_folder(struct liblttd_callbacks *data, char *relative_folder_path)
>>>>   {
>>>> -	DIR *channel_dir = opendir(subchannel_name);
>>>> -	struct dirent *entry;
>>>> -	struct stat stat_buf;
>>>>   	int ret;
>>>> -	char path_channel[PATH_MAX];
>>>> -	int path_channel_len;
>>>> -	char *path_channel_ptr;
>>>> -	char path_trace[PATH_MAX];
>>>> -	int path_trace_len;
>>>> -	char *path_trace_ptr;
>>>>   	int open_ret = 0;
>>>>
>>>> -	if(channel_dir == NULL) {
>>>> -		perror(subchannel_name);
>>>> -		open_ret = ENOENT;
>>>> -		goto end;
>>>> -	}
>>>> +	strncpy(end_path_trace, relative_folder_path, PATH_MAX - path_trace_len);
>>>> +	printf_verbose("Creating trace subdirectory %s\n", path_trace);
>>>>
>>>> -	printf_verbose("Creating trace subdirectory %s\n", subtrace_name);
>>>> -	ret = mkdir(subtrace_name, S_IRWXU|S_IRWXG|S_IRWXO);
>>>> +	ret = mkdir(path_trace, S_IRWXU|S_IRWXG|S_IRWXO);
>>>>   	if(ret == -1) {
>>>>   		if(errno != EEXIST) {
>>>> -			perror(subtrace_name);
>>>> +			perror(path_trace);
>>>>   			open_ret = -1;
>>>>   			goto end;
>>>>   		}
>>>>   	}
>>>>
>>>> -	strncpy(path_channel, subchannel_name, PATH_MAX-1);
>>>> -	path_channel_len = strlen(path_channel);
>>>> -	path_channel[path_channel_len] = '/';
>>>> -	path_channel_len++;
>>>> -	path_channel_ptr = path_channel + path_channel_len;
>>>> -
>>>> -	strncpy(path_trace, subtrace_name, PATH_MAX-1);
>>>> -	path_trace_len = strlen(path_trace);
>>>> -	path_trace[path_trace_len] = '/';
>>>> -	path_trace_len++;
>>>> -	path_trace_ptr = path_trace + path_trace_len;
>>>> -	
>>>> -#ifdef HAS_INOTIFY
>>>> -	iwatch_array->elem = realloc(iwatch_array->elem,
>>>> -		++iwatch_array->num * sizeof(struct inotify_watch));
>>>> -	
>>>> -	printf_verbose("Adding inotify for channel %s\n", path_channel);
>>>> -	iwatch_array->elem[iwatch_array->num-1].wd = inotify_add_watch(*inotify_fd, path_channel, IN_CREATE);
>>>> -	strcpy(iwatch_array->elem[iwatch_array->num-1].path_channel, path_channel);
>>>> -	strcpy(iwatch_array->elem[iwatch_array->num-1].path_trace, path_trace);
>>>> -	printf_verbose("Added inotify for channel %s, wd %u\n",
>>>> -		iwatch_array->elem[iwatch_array->num-1].path_channel,
>>>> -		iwatch_array->elem[iwatch_array->num-1].wd);
>>>> -#endif
>>>> -
>>>> -	while((entry = readdir(channel_dir)) != NULL) {
>>>> -
>>>> -		if(entry->d_name[0] == '.') continue;
>>>> -		
>>>> -		strncpy(path_channel_ptr, entry->d_name, PATH_MAX - path_channel_len);
>>>> -		strncpy(path_trace_ptr, entry->d_name, PATH_MAX - path_trace_len);
>>>> -		
>>>> -		ret = stat(path_channel,&stat_buf);
>>>> -		if(ret == -1) {
>>>> -			perror(path_channel);
>>>> -			continue;
>>>> -		}
>>>> -		
>>>> -		printf_verbose("Channel file : %s\n", path_channel);
>>>> -		
>>>> -		if(S_ISDIR(stat_buf.st_mode)) {
>>>> -
>>>> -			printf_verbose("Entering channel subdirectory...\n");
>>>> -			ret = open_channel_trace_pairs(path_channel, path_trace, fd_pairs,
>>>> -				inotify_fd, iwatch_array);
>>>> -			if(ret<  0) continue;
>>>> -		} else if(S_ISREG(stat_buf.st_mode)) {
>>>> -			open_ret = open_buffer_file(entry->d_name, path_channel, path_trace,
>>>> -				fd_pairs);
>>>> -			if(open_ret)
>>>> -				goto end;
>>>> -		}
>>>> -	}
>>>> -	
>>>>   end:
>>>> -	closedir(channel_dir);
>>>> -
>>>>   	return open_ret;
>>>>   }
>>>>
>>>> -
>>>> -int read_subbuffer(struct fd_pair *pair)
>>>> +int lttd_on_read_subbuffer(struct liblttd_callbacks *data, struct fd_pair *pair, unsigned int len)
>>>>   {
>>>> -	unsigned int consumed_old, len;
>>>> -	int err;
>>>>   	long ret;
>>>> -	off_t offset;
>>>> -
>>>> +	off_t offset = 0;
>>>>
>>>> -	err = ioctl(pair->channel, RELAY_GET_SB,&consumed_old);
>>>> -	printf_verbose("cookie : %u\n", consumed_old);
>>>> -	if(err != 0) {
>>>> -		ret = errno;
>>>> -		perror("Reserving sub buffer failed (everything is normal, it is due to concurrency)");
>>>> -		goto get_error;
>>>> -	}
>>>> -#if 0
>>>> -	err = TEMP_FAILURE_RETRY(write(pair->trace,
>>>> -				pair->mmap
>>>> -					+ (consumed_old&  ((pair->n_subbufs * pair->subbuf_size)-1)),
>>>> -				pair->subbuf_size));
>>>> -
>>>> -	if(err<  0) {
>>>> -		ret = errno;
>>>> -		perror("Error in writing to file");
>>>> -		goto write_error;
>>>> -	}
>>>> -#endif //0
>>>> -	err = ioctl(pair->channel, RELAY_GET_SB_SIZE,&len);
>>>> -	if(err != 0) {
>>>> -		ret = errno;
>>>> -		perror("Getting sub-buffer len failed.");
>>>> -		goto get_error;
>>>> -	}
>>>> -
>>>> -	offset = 0;
>>>>   	while (len>  0) {
>>>>   		printf_verbose("splice chan to pipe offset %lu\n",
>>>>   			(unsigned long)offset);
>>>> @@ -507,8 +291,9 @@ int read_subbuffer(struct fd_pair *pair)
>>>>   			perror("Error in relay splice");
>>>>   			goto write_error;
>>>>   		}
>>>> -		ret = splice(thread_pipe[0], NULL, pair->trace, NULL,
>>>> -			ret, SPLICE_F_MOVE | SPLICE_F_MORE);
>>>> +		ret = splice(thread_pipe[0], NULL,
>>>> +			((struct lttd_channel_data *)(pair->user_data))->trace,
>>>> +			NULL, ret, SPLICE_F_MOVE | SPLICE_F_MORE);
>>>>   		printf_verbose("splice pipe to file %ld\n", ret);
>>>>   		if (ret<  0) {
>>>>   			perror("Error in file splice");
>>>> @@ -517,466 +302,42 @@ int read_subbuffer(struct fd_pair *pair)
>>>>   		len -= ret;
>>>>   	}
>>>>
>>>> -#if 0
>>>> -	err = fsync(pair->trace);
>>>> -	if(err<  0) {
>>>> -		ret = errno;
>>>> -		perror("Error in writing to file");
>>>> -		goto write_error;
>>>> -	}
>>>> -#endif //0
>>>>   write_error:
>>>> -	ret = 0;
>>>> -	err = ioctl(pair->channel, RELAY_PUT_SB,&consumed_old);
>>>> -	if(err != 0) {
>>>> -		ret = errno;
>>>> -		if(errno == EFAULT) {
>>>> -			perror("Error in unreserving sub buffer\n");
>>>> -		} else if(errno == EIO) {
>>>> -			/* Should never happen with newer LTTng versions */
>>>> -			perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
>>>> -		}
>>>> -		goto get_error;
>>>> -	}
>>>> -
>>>> -get_error:
>>>> -	return ret;
>>>> -}
>>>> -
>>>> -
>>>> -int map_channels(struct channel_trace_fd *fd_pairs,
>>>> -	int idx_begin, int idx_end)
>>>> -{
>>>> -	int i,j;
>>>> -	int ret=0;
>>>> -
>>>> -	if(fd_pairs->num_pairs<= 0) {
>>>> -		printf("No channel to read\n");
>>>> -		goto end;
>>>> -	}
>>>> -	
>>>> -	/* Get the subbuf sizes and number */
>>>> -
>>>> -	for(i=idx_begin;i<idx_end;i++) {
>>>> -		struct fd_pair *pair =&fd_pairs->pair[i];
>>>> -
>>>> -		ret = ioctl(pair->channel, RELAY_GET_N_SB,&pair->n_sb);
>>>> -		if(ret != 0) {
>>>> -			perror("Error in getting the number of sub-buffers");
>>>> -			goto end;
>>>> -		}
>>>> -		ret = ioctl(pair->channel, RELAY_GET_MAX_SB_SIZE,
>>>> -			&pair->max_sb_size);
>>>> -		if(ret != 0) {
>>>> -			perror("Error in getting the max sub-buffer size");
>>>> -			goto end;
>>>> -		}
>>>> -		ret = pthread_mutex_init(&pair->mutex, NULL);	/* Fast mutex */
>>>> -		if(ret != 0) {
>>>> -			perror("Error in mutex init");
>>>> -			goto end;
>>>> -		}
>>>> -	}
>>>> -
>>>> -#if 0
>>>> -	/* Mmap each FD */
>>>> -	for(i=idx_begin;i<idx_end;i++) {
>>>> -		struct fd_pair *pair =&fd_pairs->pair[i];
>>>> -
>>>> -		pair->mmap = mmap(0, pair->subbuf_size * pair->n_subbufs, PROT_READ,
>>>> -				MAP_SHARED, pair->channel, 0);
>>>> -		if(pair->mmap == MAP_FAILED) {
>>>> -			perror("Mmap error");
>>>> -			goto munmap;
>>>> -		}
>>>> -	}
>>>> -
>>>> -	goto end; /* success */
>>>> -
>>>> -	/* Error handling */
>>>> -	/* munmap only the successfully mmapped indexes */
>>>> -munmap:
>>>> -		/* Munmap each FD */
>>>> -	for(j=idx_begin;j<i;j++) {
>>>> -		struct fd_pair *pair =&fd_pairs->pair[j];
>>>> -		int err_ret;
>>>> -
>>>> -		err_ret = munmap(pair->mmap, pair->subbuf_size * pair->n_subbufs);
>>>> -		if(err_ret != 0) {
>>>> -			perror("Error in munmap");
>>>> -		}
>>>> -		ret |= err_ret;
>>>> -	}
>>>> -
>>>> -#endif //0
>>>> -end:
>>>>   	return ret;
>>>>   }
>>>>
>>>> -int unmap_channels(struct channel_trace_fd *fd_pairs)
>>>> -{
>>>> -	int j;
>>>> -	int ret=0;
>>>> -
>>>> -	/* Munmap each FD */
>>>> -	for(j=0;j<fd_pairs->num_pairs;j++) {
>>>> -		struct fd_pair *pair =&fd_pairs->pair[j];
>>>> -		int err_ret;
>>>> -
>>>> -#if 0
>>>> -		err_ret = munmap(pair->mmap, pair->subbuf_size * pair->n_subbufs);
>>>> -		if(err_ret != 0) {
>>>> -			perror("Error in munmap");
>>>> -		}
>>>> -		ret |= err_ret;
>>>> -#endif //0
>>>> -		err_ret = pthread_mutex_destroy(&pair->mutex);
>>>> -		if(err_ret != 0) {
>>>> -			perror("Error in mutex destroy");
>>>> -		}
>>>> -		ret |= err_ret;
>>>> -	}
>>>> -
>>>> -	return ret;
>>>> -}
>>>> -
>>>> -#ifdef HAS_INOTIFY
>>>> -/* Inotify event arrived.
>>>> - *
>>>> - * Only support add file for now.
>>>> - */
>>>> -
>>>> -int read_inotify(int inotify_fd,
>>>> -	struct channel_trace_fd *fd_pairs,
>>>> -	struct inotify_watch_array *iwatch_array)
>>>> -{
>>>> -	char buf[sizeof(struct inotify_event) + PATH_MAX];
>>>> -	char path_channel[PATH_MAX];
>>>> -	char path_trace[PATH_MAX];
>>>> -	ssize_t len;
>>>> -	struct inotify_event *ievent;
>>>> -	size_t offset;
>>>> -	unsigned int i;
>>>> -	int ret;
>>>> -	int old_num;
>>>> -	
>>>> -	offset = 0;
>>>> -	len = read(inotify_fd, buf, sizeof(struct inotify_event) + PATH_MAX);
>>>> -	if(len<  0) {
>>>> -
>>>> -		if(errno == EAGAIN)
>>>> -			return 0;  /* another thread got the data before us */
>>>> -
>>>> -		printf("Error in read from inotify FD %s.\n", strerror(len));
>>>> -		return -1;
>>>> -	}
>>>> -	while(offset<  len) {
>>>> -		ievent = (struct inotify_event *)&(buf[offset]);
>>>> -		for(i=0; i<iwatch_array->num; i++) {
>>>> -			if(iwatch_array->elem[i].wd == ievent->wd&&
>>>> -				ievent->mask == IN_CREATE) {
>>>> -				printf_verbose(
>>>> -					"inotify wd %u event mask : %u for %s%s\n",
>>>> -					ievent->wd, ievent->mask,
>>>> -					iwatch_array->elem[i].path_channel,
>>>> -					ievent->name);
>>>> -				old_num = fd_pairs->num_pairs;
>>>> -				strcpy(path_channel, iwatch_array->elem[i].path_channel);
>>>> -				strcat(path_channel, ievent->name);
>>>> -				strcpy(path_trace, iwatch_array->elem[i].path_trace);
>>>> -				strcat(path_trace, ievent->name);
>>>> -				if(ret = open_buffer_file(ievent->name, path_channel,
>>>> -					path_trace, fd_pairs)) {
>>>> -					printf("Error opening buffer file\n");
>>>> -					return -1;
>>>> -				}
>>>> -				if(ret = map_channels(fd_pairs, old_num, fd_pairs->num_pairs)) {
>>>> -					printf("Error mapping channel\n");
>>>> -					return -1;
>>>> -				}
>>>> -
>>>> -			}
>>>> -		}
>>>> -		offset += sizeof(*ievent) + ievent->len;
>>>> -	}
>>>> -}
>>>> -#endif //HAS_INOTIFY
>>>> -
>>>> -/* read_channels
>>>> - *
>>>> - * Thread worker.
>>>> - *
>>>> - * Read the debugfs channels and write them in the paired tracefiles.
>>>> - *
>>>> - * @fd_pairs : paired channels and trace files.
>>>> - *
>>>> - * returns 0 on success, -1 on error.
>>>> - *
>>>> - * Note that the high priority polled channels are consumed first. We then poll
>>>> - * again to see if these channels are still in priority. Only when no
>>>> - * high priority channel is left, we start reading low priority channels.
>>>> - *
>>>> - * Note that a channel is considered high priority when the buffer is almost
>>>> - * full.
>>>> - */
>>>> -
>>>> -int read_channels(unsigned long thread_num, struct channel_trace_fd *fd_pairs,
>>>> -	int inotify_fd, struct inotify_watch_array *iwatch_array)
>>>> -{
>>>> -	struct pollfd *pollfd = NULL;
>>>> -	int num_pollfd;
>>>> -	int i,j;
>>>> -	int num_rdy, num_hup;
>>>> -	int high_prio;
>>>> -	int ret = 0;
>>>> -	int inotify_fds;
>>>> -	unsigned int old_num;
>>>> -
>>>> -#ifdef HAS_INOTIFY
>>>> -	inotify_fds = 1;
>>>> -#else
>>>> -	inotify_fds = 0;
>>>> -#endif
>>>> -
>>>> -	pthread_rwlock_rdlock(&fd_pairs_lock);
>>>> -
>>>> -	/* Start polling the FD. Keep one fd for inotify */
>>>> -	pollfd = malloc((inotify_fds + fd_pairs->num_pairs) * sizeof(struct pollfd));
>>>> -
>>>> -#ifdef HAS_INOTIFY
>>>> -	pollfd[0].fd = inotify_fd;
>>>> -	pollfd[0].events = POLLIN|POLLPRI;
>>>> -#endif
>>>> -
>>>> -	for(i=0;i<fd_pairs->num_pairs;i++) {
>>>> -		pollfd[inotify_fds+i].fd = fd_pairs->pair[i].channel;
>>>> -		pollfd[inotify_fds+i].events = POLLIN|POLLPRI;
>>>> -	}
>>>> -	num_pollfd = inotify_fds + fd_pairs->num_pairs;
>>>> -
>>>> -
>>>> -	pthread_rwlock_unlock(&fd_pairs_lock);
>>>> -
>>>> -	while(1) {
>>>> -		high_prio = 0;
>>>> -		num_hup = 0;
>>>> -#ifdef DEBUG
>>>> -		printf("Press a key for next poll...\n");
>>>> -		char buf[1];
>>>> -		read(STDIN_FILENO,&buf, 1);
>>>> -		printf("Next poll (polling %d fd) :\n", num_pollfd);
>>>> -#endif //DEBUG
>>>> -
>>>> -		/* Have we received a signal ? */
>>>> -		if(quit_program) break;
>>>> -		
>>>> -		num_rdy = poll(pollfd, num_pollfd, -1);
>>>> -
>>>> -		if(num_rdy == -1) {
>>>> -			perror("Poll error");
>>>> -			goto free_fd;
>>>> -		}
>>>> -
>>>> -		printf_verbose("Data received\n");
>>>> -#ifdef HAS_INOTIFY
>>>> -		switch(pollfd[0].revents) {
>>>> -			case POLLERR:
>>>> -				printf_verbose(
>>>> -					"Error returned in polling inotify fd %d.\n",
>>>> -					pollfd[0].fd);
>>>> -				break;
>>>> -			case POLLHUP:
>>>> -				printf_verbose(
>>>> -					"Polling inotify fd %d tells it has hung up.\n",
>>>> -					pollfd[0].fd);
>>>> -				break;
>>>> -			case POLLNVAL:
>>>> -				printf_verbose(
>>>> -					"Polling inotify fd %d tells fd is not open.\n",
>>>> -					pollfd[0].fd);
>>>> -				break;
>>>> -			case POLLPRI:
>>>> -			case POLLIN:
>>>> -				printf_verbose(
>>>> -					"Polling inotify fd %d : data ready.\n",
>>>> -					pollfd[0].fd);
>>>> -
>>>> -				pthread_rwlock_wrlock(&fd_pairs_lock);
>>>> -				read_inotify(inotify_fd, fd_pairs, iwatch_array);
>>>> -				pthread_rwlock_unlock(&fd_pairs_lock);
>>>> -
>>>> -			break;
>>>> -		}
>>>> -#endif
>>>> -
>>>> -		for(i=inotify_fds;i<num_pollfd;i++) {
>>>> -			switch(pollfd[i].revents) {
>>>> -				case POLLERR:
>>>> -					printf_verbose(
>>>> -						"Error returned in polling fd %d.\n",
>>>> -						pollfd[i].fd);
>>>> -					num_hup++;
>>>> -					break;
>>>> -				case POLLHUP:
>>>> -					printf_verbose(
>>>> -						"Polling fd %d tells it has hung up.\n",
>>>> -						pollfd[i].fd);
>>>> -					num_hup++;
>>>> -					break;
>>>> -				case POLLNVAL:
>>>> -					printf_verbose(
>>>> -						"Polling fd %d tells fd is not open.\n",
>>>> -						pollfd[i].fd);
>>>> -					num_hup++;
>>>> -					break;
>>>> -				case POLLPRI:
>>>> -					pthread_rwlock_rdlock(&fd_pairs_lock);
>>>> -					if(pthread_mutex_trylock(&fd_pairs->pair[i-inotify_fds].mutex) == 0) {
>>>> -						printf_verbose(
>>>> -							"Urgent read on fd %d\n",
>>>> -							pollfd[i].fd);
>>>> -						/* Take care of high priority channels first. */
>>>> -						high_prio = 1;
>>>> -						/* it's ok to have an unavailable sub-buffer */
>>>> -						ret = read_subbuffer(&fd_pairs->pair[i-inotify_fds]);
>>>> -						if(ret == EAGAIN) ret = 0;
>>>> -
>>>> -						ret = pthread_mutex_unlock(&fd_pairs->pair[i-inotify_fds].mutex);
>>>> -						if(ret)
>>>> -							printf("Error in mutex unlock : %s\n", strerror(ret));
>>>> -					}
>>>> -					pthread_rwlock_unlock(&fd_pairs_lock);
>>>> -					break;
>>>> -			}
>>>> -		}
>>>> -		/* If every buffer FD has hung up, we end the read loop here */
>>>> -		if(num_hup == num_pollfd - inotify_fds) break;
>>>> -
>>>> -		if(!high_prio) {
>>>> -			for(i=inotify_fds;i<num_pollfd;i++) {
>>>> -				switch(pollfd[i].revents) {
>>>> -					case POLLIN:
>>>> -						pthread_rwlock_rdlock(&fd_pairs_lock);
>>>> -						if(pthread_mutex_trylock(&fd_pairs->pair[i-inotify_fds].mutex) == 0) {
>>>> -							/* Take care of low priority channels. */
>>>> -							printf_verbose(
>>>> -								"Normal read on fd %d\n",
>>>> -								pollfd[i].fd);
>>>> -							/* it's ok to have an unavailable subbuffer */
>>>> -							ret = read_subbuffer(&fd_pairs->pair[i-inotify_fds]);
>>>> -							if(ret == EAGAIN) ret = 0;
>>>> -
>>>> -							ret = pthread_mutex_unlock(&fd_pairs->pair[i-inotify_fds].mutex);
>>>> -							if(ret)
>>>> -								printf("Error in mutex unlock : %s\n", strerror(ret));
>>>> -						}
>>>> -						pthread_rwlock_unlock(&fd_pairs_lock);
>>>> -						break;
>>>> -				}
>>>> -			}
>>>> -		}
>>>> -
>>>> -		/* Update pollfd array if an entry was added to fd_pairs */
>>>> -		pthread_rwlock_rdlock(&fd_pairs_lock);
>>>> -		if((inotify_fds + fd_pairs->num_pairs) != num_pollfd) {
>>>> -			pollfd = realloc(pollfd,
>>>> -					(inotify_fds + fd_pairs->num_pairs) * sizeof(struct pollfd));
>>>> -			for(i=num_pollfd-inotify_fds;i<fd_pairs->num_pairs;i++) {
>>>> -				pollfd[inotify_fds+i].fd = fd_pairs->pair[i].channel;
>>>> -				pollfd[inotify_fds+i].events = POLLIN|POLLPRI;
>>>> -			}
>>>> -			num_pollfd = fd_pairs->num_pairs + inotify_fds;
>>>> -		}
>>>> -		pthread_rwlock_unlock(&fd_pairs_lock);
>>>> -
>>>> -		/* NB: If the fd_pairs structure is updated by another thread from this
>>>> -		 *     point forward, the current thread will wait in the poll without
>>>> -		 *     monitoring the new channel. However, this thread will add the
>>>> -		 *     new channel on next poll (and this should not take too much time
>>>> -		 *     on a loaded system).
>>>> -		 *
>>>> -		 *     This event is quite unlikely and can only occur if a CPU is
>>>> -		 *     hot-plugged while multple lttd threads are running.
>>>> -		 */
>>>> -	}
>>>> -
>>>> -free_fd:
>>>> -	free(pollfd);
>>>> -
>>>> -end:
>>>> -	return ret;
>>>> -}
>>>> -
>>>> -
>>>> -void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs, int inotify_fd,
>>>> -	struct inotify_watch_array *iwatch_array)
>>>> -{
>>>> -	int i;
>>>> +int on_new_thread(struct liblttd_callbacks *data, unsigned long thread_num) {
>>>>   	int ret;
>>>> -
>>>> -	for(i=0;i<fd_pairs->num_pairs;i++) {
>>>> -		ret = close(fd_pairs->pair[i].channel);
>>>> -		if(ret == -1) perror("Close error on channel");
>>>> -		ret = close(fd_pairs->pair[i].trace);
>>>> -		if(ret == -1) perror("Close error on trace");
>>>> -	}
>>>> -	free(fd_pairs->pair);
>>>> -	free(iwatch_array->elem);
>>>> -}
>>>> -
>>>> -/* Thread worker */
>>>> -void * thread_main(void *arg)
>>>> -{
>>>> -	long ret;
>>>> -	unsigned long thread_num = (unsigned long)arg;
>>>> -
>>>>   	ret = pipe(thread_pipe);
>>>>   	if (ret<  0) {
>>>>   		perror("Error creating pipe");
>>>> -		return (void*)ret;
>>>> +		return ret;
>>>>   	}
>>>> -	ret = read_channels(thread_num,&fd_pairs, inotify_fd,&inotify_watch_array);
>>>> -	close(thread_pipe[0]);	/* close read end */
>>>> -	close(thread_pipe[1]);	/* close write end */
>>>> -	return (void*)ret;
>>>> +	return 0;
>>>>   }
>>>>
>>>> -
>>>> -int channels_init()
>>>> -{
>>>> -	int ret = 0;
>>>> -
>>>> -	inotify_fd = inotify_init();
>>>> -	fcntl(inotify_fd, F_SETFL, O_NONBLOCK);
>>>> -
>>>> -	if(ret = open_channel_trace_pairs(channel_name, trace_name,&fd_pairs,
>>>> -			&inotify_fd,&inotify_watch_array))
>>>> -		goto close_channel;
>>>> -	if (fd_pairs.num_pairs == 0) {
>>>> -		printf("No channel available for reading, exiting\n");
>>>> -		ret = -ENOENT;
>>>> -		goto close_channel;
>>>> -	}
>>>> -	if(ret = map_channels(&fd_pairs, 0, fd_pairs.num_pairs))
>>>> -		goto close_channel;
>>>> +int on_close_thread(struct liblttd_callbacks *data, unsigned long thread_num) {
>>>> +	close(thread_pipe[0]);	/* close read end */
>>>> +	close(thread_pipe[1]);	/* close write end */
>>>>   	return 0;
>>>> -
>>>> -close_channel:
>>>> -	close_channel_trace_pairs(&fd_pairs, inotify_fd,&inotify_watch_array);
>>>> -	if(inotify_fd>= 0)
>>>> -		close(inotify_fd);
>>>> -	return ret;
>>>>   }
>>>>
>>>> -
>>>>   int main(int argc, char ** argv)
>>>>   {
>>>>   	int ret = 0;
>>>>   	struct sigaction act;
>>>> -	pthread_t *tids;
>>>> -	unsigned long i;
>>>> -	void *tret;
>>>> -	
>>>> +
>>>> +	struct liblttd_callbacks callbacks = {
>>>> +		lttd_on_open_channel,
>>>> +		lttd_on_close_channel,
>>>> +		lttd_on_new_channels_folder,
>>>> +		lttd_on_read_subbuffer,
>>>> +		NULL,
>>>> +		on_new_thread,
>>>> +		on_close_thread,
>>>> +		NULL
>>>> +	};
>>>> +
>>>>   	ret = parse_arguments(argc, argv);
>>>>
>>>>   	if(ret != 0) show_arguments();
>>>> @@ -996,9 +357,6 @@ int main(int argc, char ** argv)
>>>>   	sigaction(SIGQUIT,&act, NULL);
>>>>   	sigaction(SIGINT,&act, NULL);
>>>>
>>>> -	if(ret = channels_init())
>>>> -		return ret;
>>>> -
>>>>   	if(daemon_mode) {
>>>>   		ret = daemon(0, 0);
>>>>
>>>> @@ -1008,33 +366,13 @@ int main(int argc, char ** argv)
>>>>   		}
>>>>   	}
>>>>
>>>> -	tids = malloc(sizeof(pthread_t) * num_threads);
>>>> -	for(i=0; i<num_threads; i++) {
>>>> -
>>>> -		ret = pthread_create(&tids[i], NULL, thread_main, (void*)i);
>>>> -		if(ret) {
>>>> -			perror("Error creating thread");
>>>> -			break;
>>>> -		}
>>>> -	}
>>>> +	strncpy(path_trace, trace_name, PATH_MAX-1);
>>>> +	path_trace_len = strlen(path_trace);
>>>> +	end_path_trace = path_trace + path_trace_len;
>>>>
>>>> -	for(i=0; i<num_threads; i++) {
>>>> -		ret = pthread_join(tids[i],&tret);
>>>> -		if(ret) {
>>>> -			perror("Error joining thread");
>>>> -			break;
>>>> -		}
>>>> -		if((long)tret != 0) {
>>>> -			printf("Error %s occured in thread %u\n",
>>>> -				strerror((long)tret), i);
>>>> -		}
>>>> -	}
>>>> +	liblttd_start(channel_name, num_threads, dump_flight_only, dump_normal_only,
>>>> +		verbose_mode,&callbacks);
>>>>
>>>> -	free(tids);
>>>> -	ret = unmap_channels(&fd_pairs);
>>>> -	close_channel_trace_pairs(&fd_pairs, inotify_fd,&inotify_watch_array);
>>>> -	if(inotify_fd>= 0)
>>>> -		close(inotify_fd);
>>>> -			
>>>>   	return ret;
>>>>   }
>>>> +
>>>>          
>>>        
>>>> diff --git a/liblttd/liblttd.c b/liblttd/liblttd.c
>>>> index 0f0e5b5..0f703f5 100644
>>>> --- a/liblttd/liblttd.c
>>>> +++ b/liblttd/liblttd.c
>>>> @@ -75,8 +75,6 @@ static inline int inotify_rm_watch (int fd, __u32 wd)
>>>>   #undef HAS_INOTIFY
>>>>   #endif
>>>>
>>>> -struct liblttd_callbacks *callbacks;
>>>> -
>>>>   struct channel_trace_fd {
>>>>   	struct fd_pair *pair;
>>>>   	int num_pairs;
>>>> @@ -93,41 +91,50 @@ struct inotify_watch_array {
>>>>   	int num;
>>>>   };
>>>>
>>>> -struct channel_trace_fd fd_pairs = { NULL, 0 };
>>>> -int inotify_fd = -1;
>>>> -struct inotify_watch_array inotify_watch_array = { NULL, 0 };
>>>> +struct liblttd_instance {
>>>> +	struct liblttd_callbacks *callbacks;
>>>> +
>>>> +	int inotify_fd;
>>>> +	struct channel_trace_fd fd_pairs;
>>>> +	struct inotify_watch_array inotify_watch_array;
>>>>
>>>> -/* protects fd_pairs and inotify_watch_array */
>>>> -pthread_rwlock_t fd_pairs_lock = PTHREAD_RWLOCK_INITIALIZER;
>>>> +	/* protects fd_pairs and inotify_watch_array */
>>>> +	pthread_rwlock_t fd_pairs_lock;
>>>>
>>>> -static char		*channel_name = NULL;
>>>> -static unsigned long	num_threads = 1;
>>>> -volatile static int	quit_program = 0;	/* For signal handler */
>>>> -static int		dump_flight_only = 0;
>>>> -static int		dump_normal_only = 0;
>>>> -static int		verbose_mode = 0;
>>>> +	char		channel_name[PATH_MAX];
>>>> +	unsigned long	num_threads;
>>>> +	int		quit_program;	/* For signal handler */
>>>> +	int		dump_flight_only;
>>>> +	int		dump_normal_only;
>>>> +	int		verbose_mode;
>>>> +};
>>>> +
>>>> +struct liblttd_thread_data {
>>>> +	int thread_num;
>>>> +	struct liblttd_instance *instance;
>>>> +};
>>>>
>>>>   #define printf_verbose(fmt, args...) \
>>>>     do {                               \
>>>> -    if (verbose_mode)                \
>>>> +    if (instance->verbose_mode)      \
>>>>         printf(fmt, ##args);           \
>>>>     } while (0)
>>>>
>>>>
>>>> -int open_buffer_file(char *filename, char *path_channel,
>>>> -	char *base_path_channel, struct channel_trace_fd *fd_pairs)
>>>> +int open_buffer_file(struct liblttd_instance *instance, char *filename,
>>>> +	char *path_channel, char *base_path_channel)
>>>>   {
>>>>   	int open_ret = 0;
>>>>   	int ret = 0;
>>>>
>>>>   	if(strncmp(filename, "flight-", sizeof("flight-")-1) != 0) {
>>>> -		if(dump_flight_only) {
>>>> +		if(instance->dump_flight_only) {
>>>>   			printf_verbose("Skipping normal channel %s\n",
>>>>   				path_channel);
>>>>   			return 0;
>>>>   		}
>>>>   	} else {
>>>> -		if(dump_normal_only) {
>>>> +		if(instance->dump_normal_only) {
>>>>   			printf_verbose("Skipping flight channel %s\n",
>>>>   				path_channel);
>>>>   			return 0;
>>>> @@ -135,26 +142,26 @@ int open_buffer_file(char *filename, char *path_channel,
>>>>   	}
>>>>   	printf_verbose("Opening file.\n");
>>>>
>>>> -	fd_pairs->pair = realloc(fd_pairs->pair,
>>>> -			++fd_pairs->num_pairs * sizeof(struct fd_pair));
>>>> +	instance->fd_pairs.pair = realloc(instance->fd_pairs.pair,
>>>> +			++instance->fd_pairs.num_pairs * sizeof(struct fd_pair));
>>>>
>>>>   	/* Open the channel in read mode */
>>>> -	fd_pairs->pair[fd_pairs->num_pairs-1].channel =
>>>> +	instance->fd_pairs.pair[instance->fd_pairs.num_pairs-1].channel =
>>>>   		open(path_channel, O_RDONLY | O_NONBLOCK);
>>>> -	if(fd_pairs->pair[fd_pairs->num_pairs-1].channel == -1) {
>>>> +	if(instance->fd_pairs.pair[instance->fd_pairs.num_pairs-1].channel == -1) {
>>>>   		perror(path_channel);
>>>> -		fd_pairs->num_pairs--;
>>>> +		instance->fd_pairs.num_pairs--;
>>>>   		return 0;	/* continue */
>>>>   	}
>>>>
>>>> -	if(callbacks->on_open_channel) ret = callbacks->on_open_channel(
>>>> -			callbacks,&fd_pairs->pair[fd_pairs->num_pairs-1],
>>>> +	if(instance->callbacks->on_open_channel) ret = instance->callbacks->on_open_channel(
>>>> +			instance->callbacks,&instance->fd_pairs.pair[instance->fd_pairs.num_pairs-1],
>>>>   			base_path_channel);
>>>>
>>>>   	if(ret != 0) {
>>>>   		open_ret = -1;
>>>> -		close(fd_pairs->pair[fd_pairs->num_pairs-1].channel);
>>>> -		fd_pairs->num_pairs--;
>>>> +		close(instance->fd_pairs.pair[instance->fd_pairs.num_pairs-1].channel);
>>>> +		instance->fd_pairs.num_pairs--;
>>>>   		goto end;
>>>>   	}
>>>>
>>>> @@ -162,10 +169,8 @@ end:
>>>>   	return open_ret;
>>>>   }
>>>>
>>>> -int open_channel_trace_pairs(char *subchannel_name,
>>>> -		char *base_subchannel_name,
>>>> -		struct channel_trace_fd *fd_pairs, int *inotify_fd,
>>>> -		struct inotify_watch_array *iwatch_array)
>>>> +int open_channel_trace_pairs(struct liblttd_instance *instance,
>>>> +	char *subchannel_name, char *base_subchannel_name)
>>>>   {
>>>>   	DIR *channel_dir = opendir(subchannel_name);
>>>>   	struct dirent *entry;
>>>> @@ -184,9 +189,9 @@ int open_channel_trace_pairs(char *subchannel_name,
>>>>   		goto end;
>>>>   	}
>>>>
>>>> -	printf_verbose("Calling on new channels folder");
>>>> -	if(callbacks->on_new_channels_folder) ret = callbacks->
>>>> -			on_new_channels_folder(callbacks,
>>>> +	printf_verbose("Calling on new channels folder\n");
>>>> +	if(instance->callbacks->on_new_channels_folder) ret = instance->callbacks->
>>>> +			on_new_channels_folder(instance->callbacks,
>>>>   			base_subchannel_name);
>>>>   	if(ret == -1) {
>>>>   		open_ret = -1;
>>>> @@ -202,18 +207,18 @@ int open_channel_trace_pairs(char *subchannel_name,
>>>>   		(base_subchannel_name - subchannel_name);
>>>>
>>>>   #ifdef HAS_INOTIFY
>>>> -	iwatch_array->elem = realloc(iwatch_array->elem,
>>>> -		++iwatch_array->num * sizeof(struct inotify_watch));
>>>> +	instance->inotify_watch_array.elem = realloc(instance->inotify_watch_array.elem,
>>>> +		++instance->inotify_watch_array.num * sizeof(struct inotify_watch));
>>>>
>>>>   	printf_verbose("Adding inotify for channel %s\n", path_channel);
>>>> -	iwatch_array->elem[iwatch_array->num-1].wd = inotify_add_watch(*inotify_fd, path_channel, IN_CREATE);
>>>> -	strcpy(iwatch_array->elem[iwatch_array->num-1].path_channel, path_channel);
>>>> -	iwatch_array->elem[iwatch_array->num-1].base_path_channel =
>>>> -		iwatch_array->elem[iwatch_array->num-1].path_channel +
>>>> +	instance->inotify_watch_array.elem[instance->inotify_watch_array.num-1].wd = inotify_add_watch(instance->inotify_fd, path_channel, IN_CREATE);
>>>> +	strcpy(instance->inotify_watch_array.elem[instance->inotify_watch_array.num-1].path_channel, path_channel);
>>>> +	instance->inotify_watch_array.elem[instance->inotify_watch_array.num-1].base_path_channel =
>>>> +		instance->inotify_watch_array.elem[instance->inotify_watch_array.num-1].path_channel +
>>>>   		(base_subchannel_name - subchannel_name);
>>>>   	printf_verbose("Added inotify for channel %s, wd %u\n",
>>>> -		iwatch_array->elem[iwatch_array->num-1].path_channel,
>>>> -		iwatch_array->elem[iwatch_array->num-1].wd);
>>>> +		instance->inotify_watch_array.elem[instance->inotify_watch_array.num-1].path_channel,
>>>> +		instance->inotify_watch_array.elem[instance->inotify_watch_array.num-1].wd);
>>>>   #endif
>>>>
>>>>   	while((entry = readdir(channel_dir)) != NULL) {
>>>> @@ -233,12 +238,11 @@ int open_channel_trace_pairs(char *subchannel_name,
>>>>   		if(S_ISDIR(stat_buf.st_mode)) {
>>>>
>>>>   			printf_verbose("Entering channel subdirectory...\n");
>>>> -			ret = open_channel_trace_pairs(path_channel, base_subchannel_ptr, fd_pairs,
>>>> -				inotify_fd, iwatch_array);
>>>> +			ret = open_channel_trace_pairs(instance, path_channel, base_subchannel_ptr);
>>>>   			if(ret<  0) continue;
>>>>   		} else if(S_ISREG(stat_buf.st_mode)) {
>>>> -			open_ret = open_buffer_file(entry->d_name, path_channel, base_subchannel_ptr,
>>>> -				fd_pairs);
>>>> +			open_ret = open_buffer_file(instance, entry->d_name,
>>>> +				path_channel, base_subchannel_ptr);
>>>>   			if(open_ret)
>>>>   				goto end;
>>>>   		}
>>>> @@ -251,7 +255,7 @@ end:
>>>>   }
>>>>
>>>>
>>>> -int read_subbuffer(struct fd_pair *pair)
>>>> +int read_subbuffer(struct liblttd_instance *instance, struct fd_pair *pair)
>>>>   {
>>>>   	unsigned int consumed_old, len;
>>>>   	int err;
>>>> @@ -274,8 +278,8 @@ int read_subbuffer(struct fd_pair *pair)
>>>>   		goto get_error;
>>>>   	}
>>>>
>>>> -	if(callbacks->on_read_subbuffer) ret = callbacks->on_read_subbuffer(
>>>> -		callbacks, pair, len);
>>>> +	if(instance->callbacks->on_read_subbuffer) ret = instance->callbacks->on_read_subbuffer(
>>>> +		instance->callbacks, pair, len);
>>>>
>>>>   write_error:
>>>>   	ret = 0;
>>>> @@ -296,13 +300,12 @@ get_error:
>>>>   }
>>>>
>>>>
>>>> -int map_channels(struct channel_trace_fd *fd_pairs,
>>>> -	int idx_begin, int idx_end)
>>>> +int map_channels(struct liblttd_instance *instance, int idx_begin, int idx_end)
>>>>   {
>>>>   	int i,j;
>>>>   	int ret=0;
>>>>
>>>> -	if(fd_pairs->num_pairs<= 0) {
>>>> +	if(instance->fd_pairs.num_pairs<= 0) {
>>>>   		printf("No channel to read\n");
>>>>   		goto end;
>>>>   	}
>>>> @@ -310,7 +313,7 @@ int map_channels(struct channel_trace_fd *fd_pairs,
>>>>   	/* Get the subbuf sizes and number */
>>>>
>>>>   	for(i=idx_begin;i<idx_end;i++) {
>>>> -		struct fd_pair *pair =&fd_pairs->pair[i];
>>>> +		struct fd_pair *pair =&instance->fd_pairs.pair[i];
>>>>
>>>>   		ret = ioctl(pair->channel, RELAY_GET_N_SB,&pair->n_sb);
>>>>   		if(ret != 0) {
>>>> @@ -334,14 +337,14 @@ end:
>>>>   	return ret;
>>>>   }
>>>>
>>>> -int unmap_channels(struct channel_trace_fd *fd_pairs)
>>>> +int unmap_channels(struct liblttd_instance *instance)
>>>>   {
>>>>   	int j;
>>>>   	int ret=0;
>>>>
>>>>   	/* Munmap each FD */
>>>> -	for(j=0;j<fd_pairs->num_pairs;j++) {
>>>> -		struct fd_pair *pair =&fd_pairs->pair[j];
>>>> +	for(j=0;j<instance->fd_pairs.num_pairs;j++) {
>>>> +		struct fd_pair *pair =&instance->fd_pairs.pair[j];
>>>>   		int err_ret;
>>>>
>>>>   		err_ret = pthread_mutex_destroy(&pair->mutex);
>>>> @@ -359,10 +362,7 @@ int unmap_channels(struct channel_trace_fd *fd_pairs)
>>>>    *
>>>>    * Only support add file for now.
>>>>    */
>>>> -
>>>> -int read_inotify(int inotify_fd,
>>>> -	struct channel_trace_fd *fd_pairs,
>>>> -	struct inotify_watch_array *iwatch_array)
>>>> +int read_inotify(struct liblttd_instance *instance)
>>>>   {
>>>>   	char buf[sizeof(struct inotify_event) + PATH_MAX];
>>>>   	char path_channel[PATH_MAX];
>>>> @@ -374,7 +374,7 @@ int read_inotify(int inotify_fd,
>>>>   	int old_num;
>>>>
>>>>   	offset = 0;
>>>> -	len = read(inotify_fd, buf, sizeof(struct inotify_event) + PATH_MAX);
>>>> +	len = read(instance->inotify_fd, buf, sizeof(struct inotify_event) + PATH_MAX);
>>>>   	if(len<  0) {
>>>>
>>>>   		if(errno == EAGAIN)
>>>> @@ -385,24 +385,24 @@ int read_inotify(int inotify_fd,
>>>>   	}
>>>>   	while(offset<  len) {
>>>>   		ievent = (struct inotify_event *)&(buf[offset]);
>>>> -		for(i=0; i<iwatch_array->num; i++) {
>>>> -			if(iwatch_array->elem[i].wd == ievent->wd&&
>>>> +		for(i=0; i<instance->inotify_watch_array.num; i++) {
>>>> +			if(instance->inotify_watch_array.elem[i].wd == ievent->wd&&
>>>>   				ievent->mask == IN_CREATE) {
>>>>   				printf_verbose(
>>>>   					"inotify wd %u event mask : %u for %s%s\n",
>>>>   					ievent->wd, ievent->mask,
>>>> -					iwatch_array->elem[i].path_channel,
>>>> +					instance->inotify_watch_array.elem[i].path_channel,
>>>>   					ievent->name);
>>>> -				old_num = fd_pairs->num_pairs;
>>>> -				strcpy(path_channel, iwatch_array->elem[i].path_channel);
>>>> +				old_num = instance->fd_pairs.num_pairs;
>>>> +				strcpy(path_channel, instance->inotify_watch_array.elem[i].path_channel);
>>>>   				strcat(path_channel, ievent->name);
>>>> -				if(ret = open_buffer_file(ievent->name, path_channel,
>>>> -					path_channel + (iwatch_array->elem[i].base_path_channel -
>>>> -					iwatch_array->elem[i].path_channel), fd_pairs)) {
>>>> +				if(ret = open_buffer_file(instance, ievent->name, path_channel,
>>>> +					path_channel + (instance->inotify_watch_array.elem[i].base_path_channel -
>>>> +					instance->inotify_watch_array.elem[i].path_channel))) {
>>>>   					printf("Error opening buffer file\n");
>>>>   					return -1;
>>>>   				}
>>>> -				if(ret = map_channels(fd_pairs, old_num, fd_pairs->num_pairs)) {
>>>> +				if(ret = map_channels(instance, old_num, instance->fd_pairs.num_pairs)) {
>>>>   					printf("Error mapping channel\n");
>>>>   					return -1;
>>>>   				}
>>>> @@ -432,8 +432,7 @@ int read_inotify(int inotify_fd,
>>>>    * full.
>>>>    */
>>>>
>>>> -int read_channels(unsigned long thread_num, struct channel_trace_fd *fd_pairs,
>>>> -	int inotify_fd, struct inotify_watch_array *iwatch_array)
>>>> +int read_channels(struct liblttd_instance *instance, unsigned long thread_num)
>>>>   {
>>>>   	struct pollfd *pollfd = NULL;
>>>>   	int num_pollfd;
>>>> @@ -450,24 +449,24 @@ int read_channels(unsigned long thread_num, struct channel_trace_fd *fd_pairs,
>>>>   	inotify_fds = 0;
>>>>   #endif
>>>>
>>>> -	pthread_rwlock_rdlock(&fd_pairs_lock);
>>>> +	pthread_rwlock_rdlock(&instance->fd_pairs_lock);
>>>>
>>>>   	/* Start polling the FD. Keep one fd for inotify */
>>>> -	pollfd = malloc((inotify_fds + fd_pairs->num_pairs) * sizeof(struct pollfd));
>>>> +	pollfd = malloc((inotify_fds + instance->fd_pairs.num_pairs) * sizeof(struct pollfd));
>>>>
>>>>   #ifdef HAS_INOTIFY
>>>> -	pollfd[0].fd = inotify_fd;
>>>> +	pollfd[0].fd = instance->inotify_fd;
>>>>   	pollfd[0].events = POLLIN|POLLPRI;
>>>>   #endif
>>>>
>>>> -	for(i=0;i<fd_pairs->num_pairs;i++) {
>>>> -		pollfd[inotify_fds+i].fd = fd_pairs->pair[i].channel;
>>>> +	for(i=0;i<instance->fd_pairs.num_pairs;i++) {
>>>> +		pollfd[inotify_fds+i].fd = instance->fd_pairs.pair[i].channel;
>>>>   		pollfd[inotify_fds+i].events = POLLIN|POLLPRI;
>>>>   	}
>>>> -	num_pollfd = inotify_fds + fd_pairs->num_pairs;
>>>> +	num_pollfd = inotify_fds + instance->fd_pairs.num_pairs;
>>>>
>>>>
>>>> -	pthread_rwlock_unlock(&fd_pairs_lock);
>>>> +	pthread_rwlock_unlock(&instance->fd_pairs_lock);
>>>>
>>>>   	while(1) {
>>>>   		high_prio = 0;
>>>> @@ -480,7 +479,7 @@ int read_channels(unsigned long thread_num, struct channel_trace_fd *fd_pairs,
>>>>   #endif //DEBUG
>>>>
>>>>   		/* Have we received a signal ? */
>>>> -		if(quit_program) break;
>>>> +		if(instance->quit_program) break;
>>>>
>>>>   		num_rdy = poll(pollfd, num_pollfd, -1);
>>>>
>>>> @@ -513,9 +512,9 @@ int read_channels(unsigned long thread_num, struct channel_trace_fd *fd_pairs,
>>>>   					"Polling inotify fd %d : data ready.\n",
>>>>   					pollfd[0].fd);
>>>>
>>>> -				pthread_rwlock_wrlock(&fd_pairs_lock);
>>>> -				read_inotify(inotify_fd, fd_pairs, iwatch_array);
>>>> -				pthread_rwlock_unlock(&fd_pairs_lock);
>>>> +				pthread_rwlock_wrlock(&instance->fd_pairs_lock);
>>>> +				read_inotify(instance);
>>>> +				pthread_rwlock_unlock(&instance->fd_pairs_lock);
>>>>
>>>>   			break;
>>>>   		}
>>>> @@ -542,22 +541,22 @@ int read_channels(unsigned long thread_num, struct channel_trace_fd *fd_pairs,
>>>>   					num_hup++;
>>>>   					break;
>>>>   				case POLLPRI:
>>>> -					pthread_rwlock_rdlock(&fd_pairs_lock);
>>>> -					if(pthread_mutex_trylock(&fd_pairs->pair[i-inotify_fds].mutex) == 0) {
>>>> +					pthread_rwlock_rdlock(&instance->fd_pairs_lock);
>>>> +					if(pthread_mutex_trylock(&instance->fd_pairs.pair[i-inotify_fds].mutex) == 0) {
>>>>   						printf_verbose(
>>>>   							"Urgent read on fd %d\n",
>>>>   							pollfd[i].fd);
>>>>   						/* Take care of high priority channels first. */
>>>>   						high_prio = 1;
>>>>   						/* it's ok to have an unavailable sub-buffer */
>>>> -						ret = read_subbuffer(&fd_pairs->pair[i-inotify_fds]);
>>>> +						ret = read_subbuffer(instance,&instance->fd_pairs.pair[i-inotify_fds]);
>>>>   						if(ret == EAGAIN) ret = 0;
>>>>
>>>> -						ret = pthread_mutex_unlock(&fd_pairs->pair[i-inotify_fds].mutex);
>>>> +						ret = pthread_mutex_unlock(&instance->fd_pairs.pair[i-inotify_fds].mutex);
>>>>   						if(ret)
>>>>   							printf("Error in mutex unlock : %s\n", strerror(ret));
>>>>   					}
>>>> -					pthread_rwlock_unlock(&fd_pairs_lock);
>>>> +					pthread_rwlock_unlock(&instance->fd_pairs_lock);
>>>>   					break;
>>>>   			}
>>>>   		}
>>>> @@ -568,38 +567,38 @@ int read_channels(unsigned long thread_num, struct channel_trace_fd *fd_pairs,
>>>>   			for(i=inotify_fds;i<num_pollfd;i++) {
>>>>   				switch(pollfd[i].revents) {
>>>>   					case POLLIN:
>>>> -						pthread_rwlock_rdlock(&fd_pairs_lock);
>>>> -						if(pthread_mutex_trylock(&fd_pairs->pair[i-inotify_fds].mutex) == 0) {
>>>> +						pthread_rwlock_rdlock(&instance->fd_pairs_lock);
>>>> +						if(pthread_mutex_trylock(&instance->fd_pairs.pair[i-inotify_fds].mutex) == 0) {
>>>>   							/* Take care of low priority channels. */
>>>>   							printf_verbose(
>>>>   								"Normal read on fd %d\n",
>>>>   								pollfd[i].fd);
>>>>   							/* it's ok to have an unavailable subbuffer */
>>>> -							ret = read_subbuffer(&fd_pairs->pair[i-inotify_fds]);
>>>> +							ret = read_subbuffer(instance,&instance->fd_pairs.pair[i-inotify_fds]);
>>>>   							if(ret == EAGAIN) ret = 0;
>>>>
>>>> -							ret = pthread_mutex_unlock(&fd_pairs->pair[i-inotify_fds].mutex);
>>>> +							ret = pthread_mutex_unlock(&instance->fd_pairs.pair[i-inotify_fds].mutex);
>>>>   							if(ret)
>>>>   								printf("Error in mutex unlock : %s\n", strerror(ret));
>>>>   						}
>>>> -						pthread_rwlock_unlock(&fd_pairs_lock);
>>>> +						pthread_rwlock_unlock(&instance->fd_pairs_lock);
>>>>   						break;
>>>>   				}
>>>>   			}
>>>>   		}
>>>>
>>>>   		/* Update pollfd array if an entry was added to fd_pairs */
>>>> -		pthread_rwlock_rdlock(&fd_pairs_lock);
>>>> -		if((inotify_fds + fd_pairs->num_pairs) != num_pollfd) {
>>>> +		pthread_rwlock_rdlock(&instance->fd_pairs_lock);
>>>> +		if((inotify_fds + instance->fd_pairs.num_pairs) != num_pollfd) {
>>>>   			pollfd = realloc(pollfd,
>>>> -					(inotify_fds + fd_pairs->num_pairs) * sizeof(struct pollfd));
>>>> -			for(i=num_pollfd-inotify_fds;i<fd_pairs->num_pairs;i++) {
>>>> -				pollfd[inotify_fds+i].fd = fd_pairs->pair[i].channel;
>>>> +					(inotify_fds + instance->fd_pairs.num_pairs) * sizeof(struct pollfd));
>>>> +			for(i=num_pollfd-inotify_fds;i<instance->fd_pairs.num_pairs;i++) {
>>>> +				pollfd[inotify_fds+i].fd = instance->fd_pairs.pair[i].channel;
>>>>   				pollfd[inotify_fds+i].events = POLLIN|POLLPRI;
>>>>   			}
>>>> -			num_pollfd = fd_pairs->num_pairs + inotify_fds;
>>>> +			num_pollfd = instance->fd_pairs.num_pairs + inotify_fds;
>>>>   		}
>>>> -		pthread_rwlock_unlock(&fd_pairs_lock);
>>>> +		pthread_rwlock_unlock(&instance->fd_pairs_lock);
>>>>
>>>>   		/* NB: If the fd_pairs structure is updated by another thread from this
>>>>   		 *     point forward, the current thread will wait in the poll without
>>>> @@ -620,104 +619,111 @@ end:
>>>>   }
>>>>
>>>>
>>>> -void close_channel_trace_pairs(struct channel_trace_fd *fd_pairs, int inotify_fd,
>>>> -	struct inotify_watch_array *iwatch_array)
>>>> +void close_channel_trace_pairs(struct liblttd_instance *instance)
>>>>   {
>>>>   	int i;
>>>>   	int ret;
>>>>
>>>> -	for(i=0;i<fd_pairs->num_pairs;i++) {
>>>> -		ret = close(fd_pairs->pair[i].channel);
>>>> +	for(i=0;i<instance->fd_pairs.num_pairs;i++) {
>>>> +		ret = close(instance->fd_pairs.pair[i].channel);
>>>>   		if(ret == -1) perror("Close error on channel");
>>>> -		if(callbacks->on_close_channel) {
>>>> -			ret = callbacks->on_close_channel(
>>>> -				callbacks,&fd_pairs->pair[i]);
>>>> +		if(instance->callbacks->on_close_channel) {
>>>> +			ret = instance->callbacks->on_close_channel(
>>>> +				instance->callbacks,&instance->fd_pairs.pair[i]);
>>>>   			if(ret != 0) perror("Error on close channel callback");
>>>>   		}
>>>>   	}
>>>> -	free(fd_pairs->pair);
>>>> -	free(iwatch_array->elem);
>>>> +	free(instance->fd_pairs.pair);
>>>> +	free(instance->inotify_watch_array.elem);
>>>>   }
>>>>
>>>>   /* Thread worker */
>>>>   void * thread_main(void *arg)
>>>>   {
>>>>   	long ret = 0;
>>>> -	unsigned long thread_num = (unsigned long)arg;
>>>> +	struct liblttd_thread_data *thread_data = (struct liblttd_thread_data*) arg;
>>>>
>>>> -	if(callbacks->on_new_thread)
>>>> -		ret = callbacks->on_new_thread(callbacks, thread_num);
>>>> +	if(thread_data->instance->callbacks->on_new_thread)
>>>> +		ret = thread_data->instance->callbacks->on_new_thread(
>>>> +		thread_data->instance->callbacks, thread_data->thread_num);
>>>>
>>>>   	if (ret<  0) {
>>>>   		return (void*)ret;
>>>>   	}
>>>> -	ret = read_channels(thread_num,&fd_pairs, inotify_fd,&inotify_watch_array);
>>>> +	ret = read_channels(thread_data->instance, thread_data->thread_num);
>>>> +
>>>> +	if(thread_data->instance->callbacks->on_close_thread)
>>>> +		thread_data->instance->callbacks->on_close_thread(
>>>> +		thread_data->instance->callbacks, thread_data->thread_num);
>>>>
>>>> -	if(callbacks->on_close_thread)
>>>> -		callbacks->on_close_thread(callbacks, thread_num);
>>>> +	free(thread_data);
>>>>
>>>>   	return (void*)ret;
>>>>   }
>>>>
>>>> -/*on_close_thread has to be reentrant, it'll be called by many threads*/
>>>> -int(*on_close_thread)(struct liblttd_callbacks *data, unsigned long thread_num);
>>>> -
>>>> -int channels_init()
>>>> +int channels_init(struct liblttd_instance *instance)
>>>>   {
>>>>   	int ret = 0;
>>>>
>>>> -	inotify_fd = inotify_init();
>>>> -	fcntl(inotify_fd, F_SETFL, O_NONBLOCK);
>>>> +	instance->inotify_fd = inotify_init();
>>>> +	fcntl(instance->inotify_fd, F_SETFL, O_NONBLOCK);
>>>>
>>>> -	if(ret = open_channel_trace_pairs(channel_name,
>>>> -			channel_name + strlen(channel_name),&fd_pairs,
>>>> -			&inotify_fd,&inotify_watch_array))
>>>> +	if(ret = open_channel_trace_pairs(instance, instance->channel_name,
>>>> +			instance->channel_name +
>>>> +			strlen(instance->channel_name)))
>>>>   		goto close_channel;
>>>> -	if (fd_pairs.num_pairs == 0) {
>>>> +	if (instance->fd_pairs.num_pairs == 0) {
>>>>   		printf("No channel available for reading, exiting\n");
>>>>   		ret = -ENOENT;
>>>>   		goto close_channel;
>>>>   	}
>>>> -	if(ret = map_channels(&fd_pairs, 0, fd_pairs.num_pairs))
>>>> +
>>>> +	if(ret = map_channels(instance, 0, instance->fd_pairs.num_pairs))
>>>>   		goto close_channel;
>>>>   	return 0;
>>>>
>>>>   close_channel:
>>>> -	close_channel_trace_pairs(&fd_pairs, inotify_fd,&inotify_watch_array);
>>>> -	if(inotify_fd>= 0)
>>>> -		close(inotify_fd);
>>>> +	close_channel_trace_pairs(instance);
>>>> +	if(instance->inotify_fd>= 0)
>>>> +		close(instance->inotify_fd);
>>>>   	return ret;
>>>>   }
>>>>
>>>> -int liblttd_start(char *channel_path, unsigned long n_threads,
>>>> -		int flight_only, int normal_only, int verbose,
>>>> -		struct liblttd_callbacks *user_data){
>>>> +int delete_instance(struct liblttd_instance *instance)
>>>> +{
>>>> +	pthread_rwlock_destroy(&instance->fd_pairs_lock);
>>>> +	free(instance);
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +int liblttd_start_instance(struct liblttd_instance *instance)
>>>> +{
>>>>   	int ret = 0;
>>>>   	pthread_t *tids;
>>>>   	unsigned long i;
>>>>   	void *tret;
>>>>
>>>> -	channel_name = channel_path;
>>>> -	num_threads = n_threads;
>>>> -	dump_flight_only = flight_only;
>>>> -	dump_normal_only = normal_only;
>>>> -	verbose_mode = verbose;
>>>> -	callbacks = user_data;
>>>> +	if(!instance)
>>>> +		return -EINVAL;
>>>>
>>>> -	if(ret = channels_init())
>>>> +	if(ret = channels_init(instance))
>>>>   		return ret;
>>>>
>>>> -	tids = malloc(sizeof(pthread_t) * num_threads);
>>>> -	for(i=0; i<num_threads; i++) {
>>>> +	tids = malloc(sizeof(pthread_t) * instance->num_threads);
>>>> +	for(i=0; i<instance->num_threads; i++) {
>>>> +		struct liblttd_thread_data *thread_data =
>>>> +			malloc(sizeof(struct liblttd_thread_data));
>>>> +		thread_data->thread_num = i;
>>>> +		thread_data->instance = instance;
>>>>
>>>> -		ret = pthread_create(&tids[i], NULL, thread_main, (void*)i);
>>>> +		ret = pthread_create(&tids[i], NULL, thread_main, thread_data);
>>>>   		if(ret) {
>>>>   			perror("Error creating thread");
>>>>   			break;
>>>>   		}
>>>>   	}
>>>>
>>>> -	for(i=0; i<num_threads; i++) {
>>>> +	for(i=0; i<instance->num_threads; i++) {
>>>>   		ret = pthread_join(tids[i],&tret);
>>>>   		if(ret) {
>>>>   			perror("Error joining thread");
>>>> @@ -730,18 +736,55 @@ int liblttd_start(char *channel_path, unsigned long n_threads,
>>>>   	}
>>>>
>>>>   	free(tids);
>>>> -	ret = unmap_channels(&fd_pairs);
>>>> -	close_channel_trace_pairs(&fd_pairs, inotify_fd,&inotify_watch_array);
>>>> -	if(inotify_fd>= 0)
>>>> -		close(inotify_fd);
>>>> +	ret = unmap_channels(instance);
>>>> +	close_channel_trace_pairs(instance);
>>>> +	if(instance->inotify_fd>= 0)
>>>> +		close(instance->inotify_fd);
>>>>
>>>> -	if(callbacks->on_trace_end) callbacks->on_trace_end(callbacks);
>>>> +	if(instance->callbacks->on_trace_end)
>>>> +		instance->callbacks->on_trace_end(instance->callbacks);
>>>> +
>>>> +	delete_instance(instance);
>>>>
>>>>   	return ret;
>>>>   }
>>>>
>>>> -int liblttd_stop() {
>>>> -	quit_program = 1;
>>>> +struct liblttd_instance * liblttd_new_instance(
>>>> +	struct liblttd_callbacks *callbacks, char *channel_path,
>>>> +	unsigned long n_threads, int flight_only, int normal_only, int verbose)
>>>> +{
>>>> +	struct liblttd_instance * instance;
>>>> +	if(!channel_path || !callbacks) return NULL;
>>>> +	if(n_threads == 0) n_threads = 1;
>>>> +	if(flight_only&&  normal_only) return NULL;
>>>> +
>>>> +	instance = malloc(sizeof(struct liblttd_instance));
>>>> +	if(!instance) return NULL;
>>>> +
>>>> +	instance->callbacks = callbacks;
>>>> +
>>>> +	instance->inotify_fd = -1;
>>>> +
>>>> +	instance->fd_pairs.pair = NULL;
>>>> +	instance->fd_pairs.num_pairs = 0;
>>>> +
>>>> +	instance->inotify_watch_array.elem = NULL;
>>>> +	instance->inotify_watch_array.num = 0;
>>>> +
>>>> +	pthread_rwlock_init(&instance->fd_pairs_lock, NULL);
>>>> +
>>>> +	strncpy(instance->channel_name, channel_path, PATH_MAX -1);
>>>> +	instance->num_threads = n_threads;
>>>> +	instance->dump_flight_only = flight_only;
>>>> +	instance->dump_normal_only = normal_only;
>>>> +	instance->verbose_mode = verbose;
>>>> +
>>>> +	return instance;
>>>> +}
>>>> +
>>>> +int liblttd_stop_instance(struct liblttd_instance *instance)
>>>> +{
>>>> +	instance->quit_program = 1;
>>>>   	return 0;
>>>>   }
>>>>
>>>> diff --git a/liblttd/liblttd.h b/liblttd/liblttd.h
>>>> index bd76eeb..02e7e9c 100644
>>>> --- a/liblttd/liblttd.h
>>>> +++ b/liblttd/liblttd.h
>>>> @@ -23,196 +23,192 @@
>>>>   #include<pthread.h>
>>>>
>>>>   /**
>>>> -* This structure contains the data associated with the channel file descriptor.
>>>> -* The lib user can use user_data to store the data associated to the specified
>>>> -* channel. The lib user can read but MUST NOT change the other attributes.
>>>> -*/
>>>> + * struct fd_pair - Contains the data associated with the channel file
>>>> + * descriptor. The lib user can use user_data to store the data associated to
>>>> + * the specified channel. The lib user can read but MUST NOT change the other
>>>> + * attributes.
>>>> + * @channel: channel file descriptor
>>>> + * @n_sb: the number of subbuffer for this channel
>>>> + * @max_sb_size: the subbuffer size for this channel
>>>> + * @mmap: Not used anymore.
>>>> + * @mutex: a mutex for internal library usage
>>>> + * @user_data: library user data
>>>> + */
>>>>   struct fd_pair {
>>>> -	/**
>>>> -	* This is the channel file descriptor.
>>>> -	*/
>>>>   	int channel;
>>>> -
>>>> -	/**
>>>> -	* This is the number of subbuffer for this channel.
>>>> -	*/
>>>>   	unsigned int n_sb;
>>>> -
>>>> -	/**
>>>> -	* This is the subbuffer size for this channel.
>>>> -	*/
>>>>   	unsigned int max_sb_size;
>>>> -
>>>> -	/**
>>>> -	* Not used anymore.
>>>> -	*/
>>>>   	void *mmap;
>>>> -
>>>> -	/**
>>>> -	* This is a mutex for internal library usage.
>>>> -	*/
>>>>   	pthread_mutex_t	mutex;
>>>> -
>>>> -	/**
>>>> -	* Library user data.
>>>> -	*/
>>>>   	void *user_data;
>>>>   };
>>>>
>>>> +struct liblttd_instance;
>>>> +
>>>>   /**
>>>> -* This structure contains the necessary callbacks for a tracing session. The
>>>> -* user can set the unnecessary functions to NULL if he does not need them.
>>>> +* struct liblttd_callbacks - Contains the necessary callbacks for a tracing
>>>> +* session. The user can set the unnecessary functions to NULL if he does not
>>>> +* need them.
>>>>   */
>>>>   struct liblttd_callbacks {
>>>>   	/**
>>>> -	* This callback is called after a channel file is open.
>>>> -	*
>>>> -	* @args data This argument is a pointeur to the callbacks struct that
>>>> -	*            has been passed to the lib.
>>>> -	* @args pair This structure contains the data associated with the
>>>> -	*            channel file descriptor. The lib user can use user_data to
>>>> -	*            store the data associated to the specified channel.
>>>> -	* @args relative_channel_path This argument represents a relative path
>>>> -	*            to the channel file. This path is relative to the root
>>>> -	*            folder of the trace channels.
>>>> -	*
>>>> -	* @return Should return 0 if the callback succeeds else not 0.
>>>> -	*/
>>>> +	 * on_open_channel - Is called after a channel file is open.
>>>> +	 * @data: pointeur to the callbacks struct that has been passed to the
>>>> +	 * lib.
>>>> +	 * @pair: structure that contains the data associated with the
>>>> +	 * channel file descriptor. The lib user can use user_data to
>>>> +	 * store the data associated to the specified channel.
>>>> +	 * @relative_channel_path: represents a relative path to the channel
>>>> +	 * file. This path is relative to the root folder of the trace channels.
>>>> +	 *
>>>> +	 * Returns 0 if the callback succeeds else not 0.
>>>> +	 */
>>>>   	int(*on_open_channel)(struct liblttd_callbacks *data,
>>>>   		struct fd_pair *pair, char *relative_channel_path);
>>>>
>>>>   	/**
>>>> -	* This callback is called after a channel file is closed.
>>>> -	*
>>>> -	* @remarks After a channel file has been closed, it will never be read
>>>> -	*            again.
>>>> -	*
>>>> -	* @args data This argument is a pointeur to the callbacks struct that
>>>> -	*            has been passed to the lib.
>>>> -	* @args pair This structure contains the data associated with the
>>>> -	*            channel file descriptor. The lib user should clean
>>>> -	*            user_data at this time.
>>>> -	*
>>>> -	* @return Should return 0 if the callback succeeds else not 0.
>>>> -	*/
>>>> +	 * on_close_channel - Is called after a channel file is closed.
>>>> +	 * @data: pointeur to the callbacks struct that has been passed to the
>>>> +	 * lib.
>>>> +	 * @pair: structure that contains the data associated with the channel
>>>> +         * file descriptor. The lib user should clean user_data at this time.
>>>> +	 *
>>>> +	 * Returns 0 if the callback succeeds else not 0.
>>>> +	 *
>>>> +	 * After a channel file has been closed, it will never be read again.
>>>> +	 */
>>>>   	int(*on_close_channel)(struct liblttd_callbacks *data,
>>>>   		struct fd_pair *pair);
>>>>
>>>> -
>>>>   	/**
>>>> -	* This callback is called when the library enter in a new subfolder
>>>> -	* while it is scanning the trace channel tree. It can be used to create
>>>> -	* the output file structure of the trace.
>>>> -	*
>>>> -	* @args data This argument is a pointeur to the callbacks struct that
>>>> -	*            has been passed to the lib.
>>>> -	* @args relative_folder_path This argument represents a relative path
>>>> -	*            to the channel folder. This path is relative to the root
>>>> -	*            folder of the trace channels.
>>>> -	*
>>>> -	* @return Should return 0 if the callback succeeds else not 0.
>>>> -	*/
>>>> +	 * on_new_channels_folder - Is called when the library enter in a new
>>>> +         * subfolder while it is scanning the trace channel tree. It can be used
>>>> +         * to create the output file structure of the trace.
>>>> +	 * @data: pointeur to the callbacks struct that has been passed to the
>>>> +	 * lib.
>>>> +	 * @relative_folder_path: represents a relative path
>>>> +	 * to the channel folder. This path is relative to the root
>>>> +	 * folder of the trace channels.
>>>> +	 *
>>>> +	 * Returns 0 if the callback succeeds else not 0.
>>>> +	 */
>>>>   	int(*on_new_channels_folder)(struct liblttd_callbacks *data,
>>>>   		char *relative_folder_path);
>>>>
>>>>   	/**
>>>> -	* This callback is called after a subbuffer is a reserved.
>>>> -	*
>>>> -	* @attention It has to be thread safe, it'll be called by many threads.
>>>> -	*
>>>> -	* @args data This argument is a pointeur to the callbacks struct that
>>>> -	*            has been passed to the lib.
>>>> -	* @args pair This structure contains the data associated with the
>>>> -	*            channel file descriptor. The lib user should clean
>>>> -	*            user_data at this time.
>>>> -	* @args len This argument represents the length the data that has to be
>>>> -	*            read.
>>>> -	*
>>>> -	* @return Should return 0 if the callback succeeds else not 0.
>>>> -	*/
>>>> +	 * on_read_subbuffer - Is called after a subbuffer is a reserved.
>>>> +	 *
>>>> +	 * @data: pointeur to the callbacks struct that has been passed to the
>>>> +	 * lib.
>>>> +	 * @pair: structure that contains the data associated with the
>>>> +	 * channel file descriptor.
>>>> +	 * @len: represents the length the data that has to be read.
>>>> +	 *
>>>> +	 * Returns 0 if the callback succeeds else not 0.
>>>> +	 *
>>>> +	 * It has to be thread safe, it'll be called by many threads.
>>>> +	 */
>>>>   	int(*on_read_subbuffer)(struct liblttd_callbacks *data,
>>>>   		struct fd_pair *pair, unsigned int len);
>>>>
>>>>   	/**
>>>> -	* This callback is called at the very end of the tracing session. At
>>>> -	* this time, all the channels have been closed and the threads have been
>>>> -	* destroyed.
>>>> -	*
>>>> -	* @remarks After this callback is called, no other callback will be
>>>> -	*            called again.
>>>> -	*
>>>> -	* @attention It has to be thread safe, it'll be called by many threads.
>>>> -	*
>>>> -	* @args data This argument is a pointeur to the callbacks struct that
>>>> -	*            has been passed to the lib.
>>>> -	*
>>>> -	* @return Should return 0 if the callback succeeds else not 0.
>>>> -	*/
>>>> +	 * on_trace_en - Is called at the very end of the tracing session. At
>>>> +	 * this time, all the channels have been closed and the threads have
>>>> +	 * been destroyed.
>>>> +	 *
>>>> +	 * @data: pointeur to the callbacks struct that has been passed to the
>>>> +	 * lib.
>>>> +	 *
>>>> +	 * Returns 0 if the callback succeeds else not 0.
>>>> +	 *
>>>> +	 * It has to be thread safe, it'll be called by many threads.
>>>> +	 * After this callback is called, no other callback will be called
>>>> +	 * again and the tracing instance will be deleted automatically by
>>>> +	 * liblttd. After this call, the user must not use the liblttd instance.
>>>> +	 */
>>>>   	int(*on_trace_end)(struct liblttd_callbacks *data);
>>>>
>>>>   	/**
>>>> -	* This callback is called after a new thread has been created.
>>>> -	*
>>>> -	* @attention It has to be thread safe, it'll be called by many threads.
>>>> -	*
>>>> -	* @args data This argument is a pointeur to the callbacks struct that
>>>> -	*            has been passed to the lib.
>>>> -	* @args thread_num This argument represents the id of the thread.
>>>> -	*
>>>> -	* @return Should return 0 if the callback succeeds else not 0.
>>>> -	*/
>>>> +	 * on_new_thread - Is called after a new thread has been created.
>>>> +	 *
>>>> +	 * @data: pointeur to the callbacks struct that has been passed to the
>>>> +	 * lib.
>>>> +	 * @thread_num: represents the id of the thread.
>>>> +	 *
>>>> +	 * Returns 0 if the callback succeeds else not 0.
>>>> +	 *
>>>> +	 * It has to be thread safe, it'll be called by many threads.
>>>> +	 */
>>>>   	int(*on_new_thread)(struct liblttd_callbacks *data,
>>>>   		unsigned long thread_num);
>>>>
>>>>   	/**
>>>> -	* This callback is called just before a thread is destroyed.
>>>> -	*
>>>> -	* @attention It has to be thread safe, it'll be called by many threads.
>>>> -	*
>>>> -	* @args data This argument is a pointeur to the callbacks struct that
>>>> -	*            has been passed to the lib.
>>>> -	* @args thread_num This argument represents the number of the thread.
>>>> -	*
>>>> -	* @return Should return 0 if the callback succeeds else not 0.
>>>> -	*/
>>>> +	 * on_close_thread - Is Called just before a thread is destroyed.
>>>> +	 *
>>>> +	 * @data: pointeur to the callbacks struct that has been passed to the
>>>> +	 * lib.
>>>> +	 * @thread_num: represents the number of the thread.
>>>> +	 *
>>>> +	 * Returns 0 if the callback succeeds else not 0.
>>>> +	 *
>>>> +	 * It has to be thread safe, it'll be called by many threads.
>>>> +	 */
>>>>   	int(*on_close_thread)(struct liblttd_callbacks *data,
>>>>   		unsigned long thread_num);
>>>>
>>>>   	/**
>>>> -	* This is where the user can put the library's data.
>>>> -	*/
>>>> +	 * The library's data.
>>>> +	 */
>>>>   	void *user_data;
>>>>   };
>>>>
>>>>   /**
>>>> -* This function is called to start a new tracing session.
>>>> -*
>>>> -* @attention It has to be thread safe, it'll be called by many threads.
>>>> -*
>>>> -* @args channel_path This argument is a path to the root folder of the trace's
>>>> -*            channels.
>>>> -* @args n_threads This argument represents the number of threads that will be
>>>> -*            used by the library.
>>>> -* @args flight_only If this argument to set to 1, only the channel that are in
>>>> -*            flight recorder mode will be recorded.
>>>> -* @args normal_only If this argument to set to 1, only the channel that are in
>>>> -*            normal mode will be recorded.
>>>> -* @args verbose If this argument to set to 1, more informations will be printed.
>>>> -* @args user_data This argument is a pointeur to the callbacks struct that
>>>> -*            contains the user's functions.
>>>> -*
>>>> -* @return Return 0 if the function succeeds else not 0.
>>>> -*/
>>>> -int liblttd_start(char *channel_path, unsigned long n_threads,
>>>> -	int flight_only, int normal_only, int verbose,
>>>> -	struct liblttd_callbacks *user_data);
>>>> + * liblttd_new_instance - Is called to create a new tracing session.
>>>> + *
>>>> + * @callbacks: Pointer to a callbacks struct that contain the user callbacks and
>>>> + * data.
>>>> + * @channel_path: This argument is a path to the root folder of the trace's
>>>> + * channels.
>>>> + * @n_threads: This argument represents the number of threads that will be
>>>> + * used by the library.
>>>> + * @flight_only: If this argument to set to 1, only the channel that are in
>>>> + * flight recorder mode will be recorded.
>>>> + * @normal_only: If this argument to set to 1, only the channel that are in
>>>> + * normal mode will be recorded.
>>>> + * @verbose: If this argument to set to 1, more informations will be printed.
>>>> + *
>>>> + * Returns the instance if the function succeeds else NULL.
>>>> + */
>>>> +struct liblttd_instance * liblttd_new_instance(
>>>> +	struct liblttd_callbacks *callbacks, char *channel_path,
>>>> +	unsigned long n_threads, int flight_only, int normal_only, int verbose);
>>>>
>>>>   /**
>>>> -* This function is called to stop a tracing session.
>>>> -*
>>>> -* @return Return 0 if the function succeeds.
>>>> -*/
>>>> -int liblttd_stop();
>>>> + * liblttd_start - Is called to start a new tracing session.
>>>> + *
>>>> + * @instance: The tracing session instance that needs to be starded.
>>>> + *
>>>> + * Returns 0 if the function succeeds.
>>>> + *
>>>> + * This is a blocking function. The caller will be bloked on it until the
>>>> + * tracing session is stoped by the user usign liblttd_stop_instance or until
>>>> + * the trace is stoped by LTTng directly.
>>>> + */
>>>> +int liblttd_start_instance(struct liblttd_instance *instance);
>>>> +
>>>> +/**
>>>> + * liblttd_stop - Is called to stop a tracing session.
>>>> + *
>>>> + * @instance: The tracing session instance that needs to be stoped.
>>>> + *
>>>> + * Returns 0 if the function succeeds.
>>>> + *
>>>> + * This function return immediately, it only tells liblttd to stop the instance.
>>>> + * The on_trace_end callback will be called when the tracing session will really
>>>> + * be stoped (after every thread will be done). The instance is deleted
>>>> + * automatically by liblttd after on_trace_end is called.
>>>> + */
>>>> +int liblttd_stop_instance(struct liblttd_instance *instance);
>>>>
>>>>   #endif /*_LIBLTTD_H */
>>>>
>>>> diff --git a/lttd/lttd.c b/lttd/lttd.c
>>>> index ec757ae..d3c12d5 100644
>>>> --- a/lttd/lttd.c
>>>> +++ b/lttd/lttd.c
>>>> @@ -46,6 +46,7 @@ struct lttd_channel_data {
>>>>   	int trace;
>>>>   };
>>>>
>>>> +struct liblttd_instance *instance;
>>>>   static char		path_trace[PATH_MAX];
>>>>   static char		*end_path_trace;
>>>>   static int		path_trace_len = 0;
>>>> @@ -191,7 +192,7 @@ void show_info(void)
>>>>   static void handler(int signo)
>>>>   {
>>>>   	printf("Signal %d received : exiting cleanly\n", signo);
>>>> -	liblttd_stop();
>>>> +	liblttd_stop_instance(instance);
>>>>   }
>>>>
>>>>   int lttd_on_open_channel(struct liblttd_callbacks *data, struct fd_pair *pair, char *relative_channel_path)
>>>> @@ -306,7 +307,8 @@ write_error:
>>>>   	return ret;
>>>>   }
>>>>
>>>> -int on_new_thread(struct liblttd_callbacks *data, unsigned long thread_num) {
>>>> +int lttd_on_new_thread(struct liblttd_callbacks *data, unsigned long thread_num)
>>>> +{
>>>>   	int ret;
>>>>   	ret = pipe(thread_pipe);
>>>>   	if (ret<  0) {
>>>> @@ -316,7 +318,8 @@ int on_new_thread(struct liblttd_callbacks *data, unsigned long thread_num) {
>>>>   	return 0;
>>>>   }
>>>>
>>>> -int on_close_thread(struct liblttd_callbacks *data, unsigned long thread_num) {
>>>> +int lttd_on_close_thread(struct liblttd_callbacks *data, unsigned long thread_num)
>>>> +{
>>>>   	close(thread_pipe[0]);	/* close read end */
>>>>   	close(thread_pipe[1]);	/* close write end */
>>>>   	return 0;
>>>> @@ -333,8 +336,8 @@ int main(int argc, char ** argv)
>>>>   		lttd_on_new_channels_folder,
>>>>   		lttd_on_read_subbuffer,
>>>>   		NULL,
>>>> -		on_new_thread,
>>>> -		on_close_thread,
>>>> +		lttd_on_new_thread,
>>>> +		lttd_on_close_thread,
>>>>   		NULL
>>>>   	};
>>>>
>>>> @@ -365,13 +368,18 @@ int main(int argc, char ** argv)
>>>>   			exit(-1);
>>>>   		}
>>>>   	}
>>>> -
>>>>   	strncpy(path_trace, trace_name, PATH_MAX-1);
>>>>   	path_trace_len = strlen(path_trace);
>>>>   	end_path_trace = path_trace + path_trace_len;
>>>>
>>>> -	liblttd_start(channel_name, num_threads, dump_flight_only, dump_normal_only,
>>>> -		verbose_mode,&callbacks);
>>>> +	instance = liblttd_new_instance(&callbacks, channel_name, num_threads,
>>>> +		dump_flight_only, dump_normal_only, verbose_mode);
>>>> +	if(!instance) {
>>>> +		perror("An error occured while creating the liblttd instance");
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	liblttd_start_instance(instance);
>>>>
>>>>   	return ret;
>>>>   }
>>>>          
>>>        
>>>> diff --git a/liblttd/Makefile.am b/liblttd/Makefile.am
>>>> index 3c1eeda..43859be 100644
>>>> --- a/liblttd/Makefile.am
>>>> +++ b/liblttd/Makefile.am
>>>> @@ -1,7 +1,7 @@
>>>>
>>>>
>>>>   lib_LTLIBRARIES = liblttd.la
>>>> -liblttd_la_SOURCES = liblttd.c
>>>> +liblttd_la_SOURCES = liblttd.c liblttdutils.c
>>>>
>>>>   liblttdinclude_HEADERS = \
>>>> -	liblttd.h
>>>> +	liblttd.h liblttdutils.h
>>>> diff --git a/liblttd/liblttd.c b/liblttd/liblttd.c
>>>> index 0f703f5..7ae01f8 100644
>>>> --- a/liblttd/liblttd.c
>>>> +++ b/liblttd/liblttd.c
>>>> @@ -1,4 +1,4 @@
>>>> -/* lttd
>>>> +/* libttd
>>>>    *
>>>>    * Linux Trace Toolkit Daemon
>>>>    *
>>>> @@ -9,6 +9,9 @@
>>>>    *
>>>>    * Copyright 2005 -
>>>>    * 	Mathieu Desnoyers<mathieu.desnoyers at polymtl.ca>
>>>> + * Copyright 2010 -
>>>> + *	Michael Sills-Lavoie<michael.sills-lavoie at polymtl.ca>
>>>> + *	Oumarou Dicko<oumarou.dicko at polymtl.ca>
>>>>    */
>>>>
>>>>   #ifdef HAVE_CONFIG_H
>>>> @@ -75,40 +78,6 @@ static inline int inotify_rm_watch (int fd, __u32 wd)
>>>>   #undef HAS_INOTIFY
>>>>   #endif
>>>>
>>>> -struct channel_trace_fd {
>>>> -	struct fd_pair *pair;
>>>> -	int num_pairs;
>>>> -};
>>>> -
>>>> -struct inotify_watch {
>>>> -	int wd;
>>>> -	char path_channel[PATH_MAX];
>>>> -	char *base_path_channel;
>>>> -};
>>>> -
>>>> -struct inotify_watch_array {
>>>> -	struct inotify_watch *elem;
>>>> -	int num;
>>>> -};
>>>> -
>>>> -struct liblttd_instance {
>>>> -	struct liblttd_callbacks *callbacks;
>>>> -
>>>> -	int inotify_fd;
>>>> -	struct channel_trace_fd fd_pairs;
>>>> -	struct inotify_watch_array inotify_watch_array;
>>>> -
>>>> -	/* protects fd_pairs and inotify_watch_array */
>>>> -	pthread_rwlock_t fd_pairs_lock;
>>>> -
>>>> -	char		channel_name[PATH_MAX];
>>>> -	unsigned long	num_threads;
>>>> -	int		quit_program;	/* For signal handler */
>>>> -	int		dump_flight_only;
>>>> -	int		dump_normal_only;
>>>> -	int		verbose_mode;
>>>> -};
>>>> -
>>>>   struct liblttd_thread_data {
>>>>   	int thread_num;
>>>>   	struct liblttd_instance *instance;
>>>> @@ -189,7 +158,7 @@ int open_channel_trace_pairs(struct liblttd_instance *instance,
>>>>   		goto end;
>>>>   	}
>>>>
>>>> -	printf_verbose("Calling on new channels folder\n");
>>>> +	printf_verbose("Calling : on new channels folder\n");
>>>>   	if(instance->callbacks->on_new_channels_folder) ret = instance->callbacks->
>>>>   			on_new_channels_folder(instance->callbacks,
>>>>   			base_subchannel_name);
>>>> @@ -742,7 +711,7 @@ int liblttd_start_instance(struct liblttd_instance *instance)
>>>>   		close(instance->inotify_fd);
>>>>
>>>>   	if(instance->callbacks->on_trace_end)
>>>> -		instance->callbacks->on_trace_end(instance->callbacks);
>>>> +		instance->callbacks->on_trace_end(instance);
>>>>
>>>>   	delete_instance(instance);
>>>>
>>>> diff --git a/liblttd/liblttd.h b/liblttd/liblttd.h
>>>> index 02e7e9c..d871dd7 100644
>>>> --- a/liblttd/liblttd.h
>>>> +++ b/liblttd/liblttd.h
>>>> @@ -1,10 +1,11 @@
>>>>   /* liblttd header file
>>>>    *
>>>> + * Copyright 2005 -
>>>> + * 		 Mathieu Desnoyers<mathieu.desnoyers at polymtl.ca>
>>>>    * Copyright 2010-
>>>>    *		 Oumarou Dicko<oumarou.dicko at polymtl.ca>
>>>>    *		 Michael Sills-Lavoie<michael.sills-lavoie at polymtl.ca>
>>>>    *
>>>> - *
>>>>    * This program is free software; you can redistribute it and/or modify
>>>>    * it under the terms of the GNU General Public License as published by
>>>>    * the Free Software Foundation; either version 2 of the License, or
>>>> @@ -21,6 +22,7 @@
>>>>   #define _LIBLTTD_H
>>>>
>>>>   #include<pthread.h>
>>>> +#include<dirent.h>
>>>>
>>>>   /**
>>>>    * struct fd_pair - Contains the data associated with the channel file
>>>> @@ -43,7 +45,46 @@ struct fd_pair {
>>>>   	void *user_data;
>>>>   };
>>>>
>>>> -struct liblttd_instance;
>>>> +struct channel_trace_fd {
>>>> +	struct fd_pair *pair;
>>>> +	int num_pairs;
>>>> +};
>>>> +
>>>> +struct inotify_watch {
>>>> +	int wd;
>>>> +	char path_channel[PATH_MAX];
>>>> +	char *base_path_channel;
>>>> +};
>>>> +
>>>> +struct inotify_watch_array {
>>>> +	struct inotify_watch *elem;
>>>> +	int num;
>>>> +};
>>>> +
>>>> +struct liblttd_callbacks;
>>>> +
>>>> +/**
>>>> + * struct liblttd_instance - Contains the data associated with a trace instance.
>>>> + * The lib user can read but MUST NOT change any attributes but callbacks.
>>>> + * @callbacks: Contains the necessary callbacks for a tracing session.
>>>> + */
>>>> +struct liblttd_instance {
>>>> +	struct liblttd_callbacks *callbacks;
>>>> +
>>>> +	int inotify_fd;
>>>> +	struct channel_trace_fd fd_pairs;
>>>> +	struct inotify_watch_array inotify_watch_array;
>>>> +
>>>> +	/* protects fd_pairs and inotify_watch_array */
>>>> +	pthread_rwlock_t fd_pairs_lock;
>>>> +
>>>> +	char channel_name[PATH_MAX];
>>>> +	unsigned long num_threads;
>>>> +	int quit_program;
>>>> +	int dump_flight_only;
>>>> +	int dump_normal_only;
>>>> +	int verbose_mode;
>>>> +};
>>>>
>>>>   /**
>>>>   * struct liblttd_callbacks - Contains the necessary callbacks for a tracing
>>>> @@ -116,17 +157,16 @@ struct liblttd_callbacks {
>>>>   	 * this time, all the channels have been closed and the threads have
>>>>   	 * been destroyed.
>>>>   	 *
>>>> -	 * @data: pointeur to the callbacks struct that has been passed to the
>>>> -	 * lib.
>>>> +	 * @instance: pointeur to the instance struct that has been passed to
>>>> +	 * the lib.
>>>>   	 *
>>>>   	 * Returns 0 if the callback succeeds else not 0.
>>>>   	 *
>>>> -	 * It has to be thread safe, it'll be called by many threads.
>>>>   	 * After this callback is called, no other callback will be called
>>>>   	 * again and the tracing instance will be deleted automatically by
>>>>   	 * liblttd. After this call, the user must not use the liblttd instance.
>>>>   	 */
>>>> -	int(*on_trace_end)(struct liblttd_callbacks *data);
>>>> +	int(*on_trace_end)(struct liblttd_instance *instance);
>>>>
>>>>   	/**
>>>>   	 * on_new_thread - Is called after a new thread has been created.
>>>> diff --git a/liblttd/liblttdutils.c b/liblttd/liblttdutils.c
>>>> new file mode 100644
>>>> index 0000000..3368aba
>>>> --- /dev/null
>>>> +++ b/liblttd/liblttdutils.c
>>>> @@ -0,0 +1,229 @@
>>>> +/* liblttdutils
>>>> + *
>>>> + * Linux Trace Toolkit utility library
>>>> + *
>>>> + * This is a simple daemon implementation that reads a few relay+debugfs
>>>> + * channels and save them in a trace.
>>>> + *
>>>> + * CPU hot-plugging is supported using inotify.
>>>> + *
>>>> + * Copyright 2005 -
>>>> + * 	Mathieu Desnoyers<mathieu.desnoyers at polymtl.ca>
>>>> + * Copyright 2010 -
>>>> + *	Michael Sills-Lavoie<michael.sills-lavoie at polymtl.ca>
>>>> + *	Oumarou Dicko<oumarou.dicko at polymtl.ca>
>>>> + */
>>>> +
>>>> +#ifdef HAVE_CONFIG_H
>>>> +#include<config.h>
>>>> +#endif
>>>> +
>>>> +#define _REENTRANT
>>>> +#define _GNU_SOURCE
>>>> +
>>>> +#include<stdio.h>
>>>> +#include<stdlib.h>
>>>> +#include<string.h>
>>>> +#include<errno.h>
>>>> +#include<fcntl.h>
>>>> +#include<dirent.h>
>>>> +#include<pthread.h>
>>>> +#include<sys/stat.h>
>>>> +
>>>> +#include "liblttdutils.h"
>>>> +
>>>> +struct liblttdutils_channel_data {
>>>> +	int trace;
>>>> +};
>>>> +
>>>> +struct liblttdutils_data {
>>>> +	char path_trace[PATH_MAX];
>>>> +	char *end_path_trace;
>>>> +	int path_trace_len;
>>>> +	int append_mode;
>>>> +	int verbose_mode;
>>>> +};
>>>> +
>>>> +static __thread int thread_pipe[2];
>>>> +
>>>> +#define printf_verbose(fmt, args...) \
>>>> +  do {                               \
>>>> +    if (callbacks_data->verbose_mode)                \
>>>> +      printf(fmt, ##args);           \
>>>> +  } while (0)
>>>> +
>>>> +int liblttdutils_local_on_open_channel(struct liblttd_callbacks *data, struct fd_pair *pair, char *relative_channel_path)
>>>> +{
>>>> +	int open_ret = 0;
>>>> +	int ret;
>>>> +	struct stat stat_buf;
>>>> +	struct liblttdutils_channel_data *channel_data;
>>>> +
>>>> +	pair->user_data = malloc(sizeof(struct liblttdutils_channel_data));
>>>> +	channel_data = pair->user_data;
>>>> +
>>>> +	struct liblttdutils_data* callbacks_data = data->user_data;
>>>> +
>>>> +	strncpy(callbacks_data->end_path_trace, relative_channel_path, PATH_MAX - callbacks_data->path_trace_len);
>>>> +	printf_verbose("Creating trace file %s\n", callbacks_data->path_trace);
>>>> +
>>>> +	ret = stat(callbacks_data->path_trace,&stat_buf);
>>>> +	if(ret == 0) {
>>>> +		if(callbacks_data->append_mode) {
>>>> +			printf_verbose("Appending to file %s as requested\n",
>>>> +				callbacks_data->path_trace);
>>>> +
>>>> +			channel_data->trace = open(callbacks_data->path_trace, O_WRONLY, S_IRWXU|S_IRWXG|S_IRWXO);
>>>> +			if(channel_data->trace == -1) {
>>>> +				perror(callbacks_data->path_trace);
>>>> +				open_ret = -1;
>>>> +				goto end;
>>>> +			}
>>>> +			ret = lseek(channel_data->trace, 0, SEEK_END);
>>>> +			if (ret<  0) {
>>>> +				perror(callbacks_data->path_trace);
>>>> +				open_ret = -1;
>>>> +				close(channel_data->trace);
>>>> +				goto end;
>>>> +			}
>>>> +		} else {
>>>> +			printf("File %s exists, cannot open. Try append mode.\n", callbacks_data->path_trace);
>>>> +			open_ret = -1;
>>>> +			goto end;
>>>> +		}
>>>> +	} else {
>>>> +		if(errno == ENOENT) {
>>>> +			channel_data->trace =
>>>> +				open(callbacks_data->path_trace, O_WRONLY|O_CREAT|O_EXCL, S_IRWXU|S_IRWXG|S_IRWXO);
>>>> +			if(channel_data->trace == -1) {
>>>> +				perror(callbacks_data->path_trace);
>>>> +				open_ret = -1;
>>>> +				goto end;
>>>> +			}
>>>> +		}
>>>> +	}
>>>> +
>>>> +end:
>>>> +	return open_ret;
>>>> +
>>>> +}
>>>> +
>>>> +int liblttdutils_local_on_close_channel(struct liblttd_callbacks *data, struct fd_pair *pair)
>>>> +{
>>>> +	int ret;
>>>> +	ret = close(((struct liblttdutils_channel_data *)(pair->user_data))->trace);
>>>> +	free(pair->user_data);
>>>> +	return ret;
>>>> +}
>>>> +
>>>> +int liblttdutils_local_on_new_channels_folder(struct liblttd_callbacks *data, char *relative_folder_path)
>>>> +{
>>>> +	int ret;
>>>> +	int open_ret = 0;
>>>> +	struct liblttdutils_data* callbacks_data = data->user_data;
>>>> +
>>>> +	strncpy(callbacks_data->end_path_trace, relative_folder_path, PATH_MAX - callbacks_data->path_trace_len);
>>>> +	printf_verbose("Creating trace subdirectory %s\n", callbacks_data->path_trace);
>>>> +
>>>> +	ret = mkdir(callbacks_data->path_trace, S_IRWXU|S_IRWXG|S_IRWXO);
>>>> +	if(ret == -1) {
>>>> +		if(errno != EEXIST) {
>>>> +			perror(callbacks_data->path_trace);
>>>> +			open_ret = -1;
>>>> +			goto end;
>>>> +		}
>>>> +	}
>>>> +
>>>> +end:
>>>> +	return open_ret;
>>>> +}
>>>> +
>>>> +int liblttdutils_local_on_read_subbuffer(struct liblttd_callbacks *data, struct fd_pair *pair, unsigned int len)
>>>> +{
>>>> +	long ret;
>>>> +	off_t offset = 0;
>>>> +
>>>> +	struct liblttdutils_data* callbacks_data = data->user_data;
>>>> +
>>>> +	while (len>  0) {
>>>> +		printf_verbose("splice chan to pipe offset %lu\n",
>>>> +			(unsigned long)offset);
>>>> +		ret = splice(pair->channel,&offset, thread_pipe[1], NULL,
>>>> +			len, SPLICE_F_MOVE | SPLICE_F_MORE);
>>>> +		printf_verbose("splice chan to pipe ret %ld\n", ret);
>>>> +		if (ret<  0) {
>>>> +			perror("Error in relay splice");
>>>> +			goto write_error;
>>>> +		}
>>>> +		ret = splice(thread_pipe[0], NULL,
>>>> +			((struct liblttdutils_channel_data *)(pair->user_data))->trace,
>>>> +			NULL, ret, SPLICE_F_MOVE | SPLICE_F_MORE);
>>>> +		printf_verbose("splice pipe to file %ld\n", ret);
>>>> +		if (ret<  0) {
>>>> +			perror("Error in file splice");
>>>> +			goto write_error;
>>>> +		}
>>>> +		len -= ret;
>>>> +	}
>>>> +
>>>> +write_error:
>>>> +	return ret;
>>>> +}
>>>> +
>>>> +int liblttdutils_local_on_new_thread(struct liblttd_callbacks *data, unsigned long thread_num)
>>>> +{
>>>> +	int ret;
>>>> +	ret = pipe(thread_pipe);
>>>> +	if (ret<  0) {
>>>> +		perror("Error creating pipe");
>>>> +		return ret;
>>>> +	}
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +int liblttdutils_local_on_close_thread(struct liblttd_callbacks *data, unsigned long thread_num)
>>>> +{
>>>> +	close(thread_pipe[0]);	/* close read end */
>>>> +	close(thread_pipe[1]);	/* close write end */
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +int liblttdutils_local_on_trace_end(struct liblttd_instance *instance)
>>>> +{
>>>> +	struct liblttd_callbacks *callbacks = instance->callbacks;
>>>> +	struct liblttdutils_data *data = callbacks->user_data;
>>>> +
>>>> +	free(data);
>>>> +	free(callbacks);
>>>> +}
>>>> +
>>>> +struct liblttd_callbacks* liblttdutils_local_new_callbacks(char* trace_name,
>>>> +	int append_mode, int verbose_mode)
>>>> +{
>>>> +	struct liblttdutils_data *data;
>>>> +	struct liblttd_callbacks *callbacks;
>>>> +
>>>> +	if(!trace_name) return NULL;
>>>> +
>>>> +	data = malloc(sizeof(struct liblttdutils_data));
>>>> +
>>>> +	strncpy(data->path_trace, trace_name, PATH_MAX-1);
>>>> +	data->path_trace_len = strlen(data->path_trace);
>>>> +	data->end_path_trace = data->path_trace + data->path_trace_len;
>>>> +	data->append_mode = append_mode;
>>>> +	data->verbose_mode = verbose_mode;
>>>> +
>>>> +	callbacks = malloc(sizeof(struct liblttd_callbacks));
>>>> +
>>>> +	callbacks->on_open_channel = liblttdutils_local_on_open_channel;
>>>> +	callbacks->on_close_channel = liblttdutils_local_on_close_channel;
>>>> +	callbacks->on_new_channels_folder = liblttdutils_local_on_new_channels_folder;
>>>> +	callbacks->on_read_subbuffer = liblttdutils_local_on_read_subbuffer;
>>>> +	callbacks->on_trace_end = liblttdutils_local_on_trace_end;
>>>> +	callbacks->on_new_thread = liblttdutils_local_on_new_thread;
>>>> +	callbacks->on_close_thread = liblttdutils_local_on_close_thread;
>>>> +	callbacks->user_data = data;
>>>> +
>>>> +	return callbacks;
>>>> +}
>>>> +
>>>> diff --git a/liblttd/liblttdutils.h b/liblttd/liblttdutils.h
>>>> new file mode 100644
>>>> index 0000000..78439d2
>>>> --- /dev/null
>>>> +++ b/liblttd/liblttdutils.h
>>>> @@ -0,0 +1,38 @@
>>>> +/* liblttdutils header file
>>>> + *
>>>> + * Copyright 2010-
>>>> + *		 Oumarou Dicko<oumarou.dicko at polymtl.ca>
>>>> + *		 Michael Sills-Lavoie<michael.sills-lavoie at polymtl.ca>
>>>> + *
>>>> + * This program is free software; you can redistribute it and/or modify
>>>> + * it under the terms of the GNU General Public License as published by
>>>> + * the Free Software Foundation; either version 2 of the License, or
>>>> + * (at your option) any later version.
>>>> + *
>>>> + * This program is distributed in the hope that it will be useful,
>>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the
>>>> + * GNU General Public License for more details.
>>>> + *
>>>> + */
>>>> +
>>>> +#ifndef _LIBLTTDUTILS_H
>>>> +#define _LIBLTTDUTILS_H
>>>> +
>>>> +#include "liblttd.h"
>>>> +
>>>> +/**
>>>> + * liblttdutils_new_callbacks - Is a utility function called to create a new
>>>> + * callbacks struct used by liblttd to write trace data to the disk.
>>>> + *
>>>> + * @trace_name: Directory name of the trace to write to. It will be created.
>>>> + * @append_mode: Append to a possibly existing trace.
>>>> + * @verbose_mode: Verbose mode.
>>>> + *
>>>> + * Returns the callbacks if the function succeeds else NULL.
>>>> + */
>>>> +struct liblttd_callbacks* liblttdutils_local_new_callbacks(char* trace_name,
>>>> +	int append_mode, int verbose_mode);
>>>> +
>>>> +#endif /*_LIBLTTDUTILS_H */
>>>> +
>>>> diff --git a/lttd/lttd.c b/lttd/lttd.c
>>>> index d3c12d5..b43b637 100644
>>>> --- a/lttd/lttd.c
>>>> +++ b/lttd/lttd.c
>>>> @@ -8,6 +8,8 @@
>>>>    * CPU hot-plugging is supported using inotify.
>>>>    *
>>>>    * Copyright 2009-2010 - Mathieu Desnoyers<mathieu.desnoyers at efficios.com>
>>>> + * Copyright 2010 - Michael Sills-Lavoie<michael.sills-lavoie at polymtl.ca>
>>>> + * Copyright 2010 - Oumarou Dicko<oumarou.dicko at polymtl.ca>
>>>>    *
>>>>    * This program is free software; you can redistribute it and/or modify
>>>>    * it under the terms of the GNU General Public License as published by
>>>> @@ -22,6 +24,7 @@
>>>>    * You should have received a copy of the GNU General Public License along
>>>>    * with this program; if not, write to the Free Software Foundation, Inc.,
>>>>    * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
>>>> + *
>>>>    */
>>>>
>>>>   #ifdef HAVE_CONFIG_H
>>>> @@ -33,23 +36,14 @@
>>>>
>>>>   #include<stdio.h>
>>>>   #include<stdlib.h>
>>>> -#include<string.h>
>>>>   #include<signal.h>
>>>>   #include<errno.h>
>>>> -#include<fcntl.h>
>>>> -#include<dirent.h>
>>>> -#include<sys/stat.h>
>>>>
>>>>   #include<liblttd/liblttd.h>
>>>> +#include<liblttd/liblttdutils.h>
>>>>
>>>> -struct lttd_channel_data {
>>>> -	int trace;
>>>> -};
>>>> +struct liblttd_instance* instance;
>>>>
>>>> -struct liblttd_instance *instance;
>>>> -static char		path_trace[PATH_MAX];
>>>> -static char		*end_path_trace;
>>>> -static int		path_trace_len = 0;
>>>>   static char		*trace_name = NULL;
>>>>   static char		*channel_name = NULL;
>>>>   static int		daemon_mode = 0;
>>>> @@ -59,13 +53,6 @@ static int		dump_flight_only = 0;
>>>>   static int		dump_normal_only = 0;
>>>>   static int		verbose_mode = 0;
>>>>
>>>> -static __thread int thread_pipe[2];
>>>> -
>>>> -#define printf_verbose(fmt, args...) \
>>>> -  do {                               \
>>>> -    if (verbose_mode)                \
>>>> -      printf(fmt, ##args);           \
>>>> -  } while (0)
>>>>
>>>>   /* Args :
>>>>    *
>>>> @@ -195,152 +182,11 @@ static void handler(int signo)
>>>>   	liblttd_stop_instance(instance);
>>>>   }
>>>>
>>>> -int lttd_on_open_channel(struct liblttd_callbacks *data, struct fd_pair *pair, char *relative_channel_path)
>>>> -{
>>>> -	int open_ret = 0;
>>>> -	int ret;
>>>> -	struct stat stat_buf;
>>>> -	struct lttd_channel_data *channel_data;
>>>> -
>>>> -	pair->user_data = malloc(sizeof(struct lttd_channel_data));
>>>> -	channel_data = pair->user_data;
>>>> -
>>>> -	strncpy(end_path_trace, relative_channel_path, PATH_MAX - path_trace_len);
>>>> -	printf_verbose("Creating trace file %s\n", path_trace);
>>>> -
>>>> -	ret = stat(path_trace,&stat_buf);
>>>> -	if(ret == 0) {
>>>> -		if(append_mode) {
>>>> -			printf_verbose("Appending to file %s as requested\n",
>>>> -				path_trace);
>>>> -
>>>> -			channel_data->trace = open(path_trace, O_WRONLY, S_IRWXU|S_IRWXG|S_IRWXO);
>>>> -			if(channel_data->trace == -1) {
>>>> -				perror(path_trace);
>>>> -				open_ret = -1;
>>>> -				goto end;
>>>> -			}
>>>> -			ret = lseek(channel_data->trace, 0, SEEK_END);
>>>> -			if (ret<  0) {
>>>> -				perror(path_trace);
>>>> -				open_ret = -1;
>>>> -				close(channel_data->trace);
>>>> -				goto end;
>>>> -			}
>>>> -		} else {
>>>> -			printf("File %s exists, cannot open. Try append mode.\n", path_trace);
>>>> -			open_ret = -1;
>>>> -			goto end;
>>>> -		}
>>>> -	} else {
>>>> -		if(errno == ENOENT) {
>>>> -			channel_data->trace = open(path_trace, O_WRONLY|O_CREAT|O_EXCL, S_IRWXU|S_IRWXG|S_IRWXO);
>>>> -			if(channel_data->trace == -1) {
>>>> -				perror(path_trace);
>>>> -				open_ret = -1;
>>>> -				goto end;
>>>> -			}
>>>> -		}
>>>> -	}
>>>> -
>>>> -end:
>>>> -	return open_ret;
>>>> -
>>>> -}
>>>> -
>>>> -int lttd_on_close_channel(struct liblttd_callbacks *data, struct fd_pair *pair)
>>>> -{
>>>> -	int ret;
>>>> -	ret = close(((struct lttd_channel_data *)(pair->user_data))->trace);
>>>> -	free(pair->user_data);
>>>> -	return ret;
>>>> -}
>>>> -
>>>> -int lttd_on_new_channels_folder(struct liblttd_callbacks *data, char *relative_folder_path)
>>>> -{
>>>> -	int ret;
>>>> -	int open_ret = 0;
>>>> -
>>>> -	strncpy(end_path_trace, relative_folder_path, PATH_MAX - path_trace_len);
>>>> -	printf_verbose("Creating trace subdirectory %s\n", path_trace);
>>>> -
>>>> -	ret = mkdir(path_trace, S_IRWXU|S_IRWXG|S_IRWXO);
>>>> -	if(ret == -1) {
>>>> -		if(errno != EEXIST) {
>>>> -			perror(path_trace);
>>>> -			open_ret = -1;
>>>> -			goto end;
>>>> -		}
>>>> -	}
>>>> -
>>>> -end:
>>>> -	return open_ret;
>>>> -}
>>>> -
>>>> -int lttd_on_read_subbuffer(struct liblttd_callbacks *data, struct fd_pair *pair, unsigned int len)
>>>> -{
>>>> -	long ret;
>>>> -	off_t offset = 0;
>>>> -
>>>> -	while (len>  0) {
>>>> -		printf_verbose("splice chan to pipe offset %lu\n",
>>>> -			(unsigned long)offset);
>>>> -		ret = splice(pair->channel,&offset, thread_pipe[1], NULL,
>>>> -			len, SPLICE_F_MOVE | SPLICE_F_MORE);
>>>> -		printf_verbose("splice chan to pipe ret %ld\n", ret);
>>>> -		if (ret<  0) {
>>>> -			perror("Error in relay splice");
>>>> -			goto write_error;
>>>> -		}
>>>> -		ret = splice(thread_pipe[0], NULL,
>>>> -			((struct lttd_channel_data *)(pair->user_data))->trace,
>>>> -			NULL, ret, SPLICE_F_MOVE | SPLICE_F_MORE);
>>>> -		printf_verbose("splice pipe to file %ld\n", ret);
>>>> -		if (ret<  0) {
>>>> -			perror("Error in file splice");
>>>> -			goto write_error;
>>>> -		}
>>>> -		len -= ret;
>>>> -	}
>>>> -
>>>> -write_error:
>>>> -	return ret;
>>>> -}
>>>> -
>>>> -int lttd_on_new_thread(struct liblttd_callbacks *data, unsigned long thread_num)
>>>> -{
>>>> -	int ret;
>>>> -	ret = pipe(thread_pipe);
>>>> -	if (ret<  0) {
>>>> -		perror("Error creating pipe");
>>>> -		return ret;
>>>> -	}
>>>> -	return 0;
>>>> -}
>>>> -
>>>> -int lttd_on_close_thread(struct liblttd_callbacks *data, unsigned long thread_num)
>>>> -{
>>>> -	close(thread_pipe[0]);	/* close read end */
>>>> -	close(thread_pipe[1]);	/* close write end */
>>>> -	return 0;
>>>> -}
>>>> -
>>>>   int main(int argc, char ** argv)
>>>>   {
>>>>   	int ret = 0;
>>>>   	struct sigaction act;
>>>>
>>>> -	struct liblttd_callbacks callbacks = {
>>>> -		lttd_on_open_channel,
>>>> -		lttd_on_close_channel,
>>>> -		lttd_on_new_channels_folder,
>>>> -		lttd_on_read_subbuffer,
>>>> -		NULL,
>>>> -		lttd_on_new_thread,
>>>> -		lttd_on_close_thread,
>>>> -		NULL
>>>> -	};
>>>> -
>>>>   	ret = parse_arguments(argc, argv);
>>>>
>>>>   	if(ret != 0) show_arguments();
>>>> @@ -368,12 +214,13 @@ int main(int argc, char ** argv)
>>>>   			exit(-1);
>>>>   		}
>>>>   	}
>>>> -	strncpy(path_trace, trace_name, PATH_MAX-1);
>>>> -	path_trace_len = strlen(path_trace);
>>>> -	end_path_trace = path_trace + path_trace_len;
>>>>
>>>> -	instance = liblttd_new_instance(&callbacks, channel_name, num_threads,
>>>> +	struct liblttd_callbacks* callbacks = liblttdutils_local_new_callbacks(
>>>> +		trace_name, append_mode, verbose_mode);
>>>> +
>>>> +	instance = liblttd_new_instance(callbacks, channel_name, num_threads,
>>>>   		dump_flight_only, dump_normal_only, verbose_mode);
>>>> +
>>>>   	if(!instance) {
>>>>   		perror("An error occured while creating the liblttd instance");
>>>>   		return ret;
>>>>          
>>>
>>> -- 
>>> Mathieu Desnoyers
>>> Operating System Efficiency R&D Consultant
>>> EfficiOS Inc.
>>> http://www.efficios.com
>>>
>>> _______________________________________________
>>> ltt-dev mailing list
>>> ltt-dev at lists.casi.polymtl.ca
>>> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
>>>
>>>        
>> -- 
>> Mathieu Desnoyers
>> Operating System Efficiency R&D Consultant
>> EfficiOS Inc.
>> http://www.efficios.com
>>
>> _______________________________________________
>> ltt-dev mailing list
>> ltt-dev at lists.casi.polymtl.ca
>> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
>>
>>      
>    





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