[ltt-dev] [UST PATCH] Re-write ustcomm parts of UST

David Goulet david.goulet at polymtl.ca
Fri Sep 24 08:25:40 EDT 2010


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On 10-09-24 02:42 AM, Nils Carlson wrote:
> Hi David,
> 
> On Thu, 23 Sep 2010, David Goulet wrote:
> 
> Hey Nils,
> 
> I'll check carefully this patch tomorrow but until that time we might
> consider
> this for a communication protocol. Since TCF is using JSON protocol,
> we can use
> that for UST. We have a LTTng and UST TCF agent so unifying everything
> would be
> ideal.
> 
>> Beware, this is not an external communication protocol I've been working
>> on. It's an internal one, intra-library. And as we build everything at
>> once with the same headers etc. we can make all sorts of assumptions
>> that wouldn't be valid in anything else.

Yes I know that but how can this stop us from still using JSON?

David

> 
>> /Nils
> 
> 
> As Mathieu suggest, and it was brought up at the CDT Summit this week,
> is that
> we should *not* be dependent on the TCF JSON library and consider
> using the
> libjson (http://oss.metaparadigm.com/json-c/) or our own implementation.
> 
> Cheers
> David
> 
> On 10-09-23 06:13 AM, Nils Carlson wrote:
>>>> This is a very big patch, and so it requires a bit of explaining.
>>>>
>>>> This patch is a step on the way of accomplishing serveral goals I
>>>> have in this
>>>> area:
>>>>
>>>> 1. Use enums for commands and eliminate text-based commands. This
>>>> does not mean
>>>>    that we will stop processing strings for trace/channel and marker
>>>> names;
>>>>    just that the long series of if statements with token and string
>>>> matching
>>>>    will be replaced with a switch statement. To this end I have
>>>> created a
>>>>    ustcomm_header struct that contains the length of the data-field
>>>> and some
>>>>    other fields. This allows us to first receive the header, allocate
>>>> memory
>>>>    for the data and then receive the data; eliminating all scanning
>>>> of messages.
>>>>
>>>> 2. Reduce the complexity of the implementation. To put it simply, I
>>>> don't like
>>>>    callbacks. They reduce transparency and make it difficult to
>>>> follow the
>>>>    flow of the code; so I have eliminated multipoll replacing it with
>>>> a normal
>>>>    epoll. I have also replaced almost all the different server,
>>>> connection and
>>>>    source structs with one, called ustcomm_sock.
>>>>
>>>> 3. Make ustd scale better. Currently ustd scales terribly. We
>>>> allocate one
>>>>    thread per-cpu per-channel per-process, five applications each
>>>> with three
>>>>    channels on a four cpu machine leads to 5*3*4=60 threads. Part of
>>>> the reason
>>>>    for this multitude of threads was that we used a ustcomm_request call
>>>>    (consisting of a send and a receive) to wait for a subbuffer to be
>>>> written.
>>>>    The sequence for a subbuffer to be written was as follows:
>>>>
>>>>       Ustd calls send with a 'get_subbuffer' command, and then recv
>>>> in one of
>>>>       the threads and hangs on the recv on the socket.
>>>>
>>>>       Upon filling the subbuffer the traced app writes '1' to a pipe.
>>>>
>>>>       The ust_thread inside the app which was listening to the other
>>>> end of the
>>>>       pipe wakes up when the '1' is written. The callback from
>>>> multipoll calls
>>>>       a send which sends a reply to the ustd thread over the socket.
>>>>
>>>>       The ustd thread wakes up and reads the message, continuing
>>>> along in its
>>>>       execution.
>>>>
>>>>    I replace this with a bit of a different mechanism, which should
>>>> allow us
>>>>    to eventually reduce the number of threads to one per cpu:
>>>>
>>>>       Ustd requests a buffer_fd which causes the ustd_thread inside
>>>> the app
>>>>       to send the file-descriptor for the read en of the pipe to ustd.
>>>>
>>>>       The ustd thread now does a read on the pipe, halting its
>>>> execution until
>>>>       the app fills the subbuffer and writes '1' to the pipe, waking
>>>> up the ustd
>>>>       thread.
>>>>
>>>>       Ustd now makes the 'get_subbuffer' call which the ust_thread
>>>> inside the
>>>>       app responds to with information about the subbuffer. Writes it
>>>> and then
>>>>       goes back to the read call, hanging on the pipe.
>>>>
>>>>    So we are still stuck on the multitude of threads, but we are in
>>>> much better
>>>>    position to move forward. Replacing the read with an epoll
>>>> statement and then
>>>>    pointing the epoll event data at the buffer struct containing the
>>>> current
>>>>    buffer to whitch the pipe belongs should be relatively easy. We
>>>> can then
>>>>    instead of spawning a new thread for each buffer just allocate the
>>>>    buffer_info struct and assign it to one of the per-cpu threads in
>>>> ustd to
>>>>    poll on.
>>>>
>>>> 4. Replace poll with epoll which scales better, especially for
>>>>    events << (nr of fds). This is complete.
>>>>
>>>> 5. Allow UST to handle arbitrarily long unix socket names. This is
>>>> done by
>>>>    carefull allocation of the socketaddr_un struct with a dynamic
>>>> length.
>>>>    Truncating is ugly and dangerous.
>>>>
>>>> There is a lot of work still left to be done. This is only the first
>>>> of a
>>>> number of patches that I expect in this area. If someone feels like
>>>> tackling
>>>> ustd head on to reduce the number of threads that would be great.
>>>>
>>>> I have kept Pierre-Marc's form of error handling for the I/O wrapping
>>>> functions
>>>> because I want to propagate return codes up to the apps that are
>>>> using them
>>>> so they can close file-descriptors and free associated resources. If
>>>> somebody
>>>> knows of a better approach please make yourself heard.
>>>>
>>>> Signed-off-by: Nils Carlson <nils.carlson at ericsson.com>
>>>> ---
>>>>  include/ust/ustd.h     |   12 +-
>>>>  libust/buffers.h       |    5 +
>>>>  libust/tracectl.c      |  474 ++++++++++++++----------
>>>>  libustcmd/ustcmd.c     |   15 +-
>>>>  libustcomm/Makefile.am |    5 +-
>>>>  libustcomm/multipoll.c |  130 -------
>>>>  libustcomm/multipoll.h |   44 ---
>>>>  libustcomm/ustcomm.c   |  969
>>>> +++++++++++++++++++-----------------------------
>>>>  libustcomm/ustcomm.h   |   83 ++---
>>>>  libustd/libustd.c      |  277 ++++++++++-----
>>>>  10 files changed, 902 insertions(+), 1112 deletions(-)
>>>>  delete mode 100644 libustcomm/multipoll.c
>>>>  delete mode 100644 libustcomm/multipoll.h
>>>>
>>>> diff --git a/include/ust/ustd.h b/include/ust/ustd.h
>>>> index 5fec7f9..7ce063f 100644
>>>> --- a/include/ust/ustd.h
>>>> +++ b/include/ust/ustd.h
>>>> @@ -29,16 +29,18 @@
>>>>  #include <pthread.h>
>>>>  #include <dirent.h>
>>>>  #include <ust/kcompat/kcompat.h>
>>>> +#include <urcu/list.h>
>>>>
>>>>  #define USTD_DEFAULT_TRACE_PATH "/tmp/usttrace"
>>>>
>>>> -struct ustcomm_connection;
>>>> -struct ustcomm_ustd;
>>>> +struct ustcomm_sock;
>>>>
>>>>  struct buffer_info {
>>>>       const char *name;
>>>>       pid_t pid;
>>>> -     struct ustcomm_connection *conn;
>>>> +     int app_sock;
>>>> +     /* The pipe file descriptor */
>>>> +     int pipe_fd;
>>>>
>>>>       int shmid;
>>>>       int bufstruct_shmid;
>>>> @@ -73,7 +75,9 @@ struct libustd_instance {
>>>>       struct libustd_callbacks *callbacks;
>>>>       int quit_program;
>>>>       int is_init;
>>>> -     struct ustcomm_ustd *comm;
>>>> +     struct list_head connections;
>>>> +     int epoll_fd;
>>>> +     struct ustcomm_sock *listen_sock;
>>>>       char *sock_path;
>>>>       pthread_mutex_t mutex;
>>>>       int active_buffers;
>>>> diff --git a/libust/buffers.h b/libust/buffers.h
>>>> index 3044500..a2ad83e 100644
>>>> --- a/libust/buffers.h
>>>> +++ b/libust/buffers.h
>>>> @@ -82,6 +82,11 @@ struct ust_buffer {
>>>>       int data_ready_fd_write;
>>>>       /* the reading end of the pipe */
>>>>       int data_ready_fd_read;
>>>> +     /*
>>>> +      * List of buffers with an open pipe, used for fork and forced
>>>> subbuffer
>>>> +      * switch.
>>>> +      */
>>>> +     struct list_head open_buffers_list;
>>>>
>>>>       unsigned int finalized;
>>>>  //ust//      struct timer_list switch_timer; /* timer for periodical
>>>> switch */
>>>> diff --git a/libust/tracectl.c b/libust/tracectl.c
>>>> index 60c375b..3472ca9 100644
>>>> --- a/libust/tracectl.c
>>>> +++ b/libust/tracectl.c
>>>> @@ -26,13 +26,15 @@
>>>>  #include <stdint.h>
>>>>  #include <pthread.h>
>>>>  #include <signal.h>
>>>> +#include <sys/epoll.h>
>>>> +#include <sys/time.h>
>>>>  #include <sys/types.h>
>>>>  #include <sys/socket.h>
>>>> -#include <sys/un.h>
>>>>  #include <fcntl.h>
>>>>  #include <poll.h>
>>>>  #include <regex.h>
>>>>  #include <urcu/uatomic_arch.h>
>>>> +#include <urcu/list.h>
>>>>
>>>>  #include <ust/marker.h>
>>>>  #include <ust/tracepoint.h>
>>>> @@ -42,7 +44,6 @@
>>>>  #include "ustcomm.h"
>>>>  #include "buffers.h"
>>>>  #include "marker-control.h"
>>>> -#include "multipoll.h"
>>>>
>>>>  #define USTSIGNAL SIGIO
>>>>
>>>> @@ -55,50 +56,18 @@
>>>>   */
>>>>  s64 pidunique = -1LL;
>>>>
>>>> -extern struct chan_info_struct chan_infos[];
>>>> +static int epoll_fd;
>>>> +static struct ustcomm_sock *listen_sock;
>>>>
>>>> -struct list_head blocked_consumers = LIST_HEAD_INIT(blocked_consumers);
>>>> +extern struct chan_info_struct chan_infos[];
>>>>
>>>> -static struct ustcomm_app ustcomm_app;
>>>> +static struct list_head open_buffers_list =
>>>> LIST_HEAD_INIT(open_buffers_list);
>>>>
>>>> -struct tracecmd { /* no padding */
>>>> -     uint32_t size;
>>>> -     uint16_t command;
>>>> -};
>>>> +static struct list_head ust_socks = LIST_HEAD_INIT(ust_socks);
>>>>
>>>>  /* volatile because shared between the listener and the main thread */
>>>>  int buffers_to_export = 0;
>>>>
>>>> -struct trctl_msg {
>>>> -     /* size: the size of all the fields except size itself */
>>>> -     uint32_t size;
>>>> -     uint16_t type;
>>>> -     /* Only the necessary part of the payload is transferred. It
>>>> -         * may even be none of it.
>>>> -         */
>>>> -     char payload[94];
>>>> -};
>>>> -
>>>> -struct consumer_channel {
>>>> -     int fd;
>>>> -     struct ltt_channel_struct *chan;
>>>> -};
>>>> -
>>>> -struct blocked_consumer {
>>>> -     int fd_consumer;
>>>> -     int fd_producer;
>>>> -     int tmp_poll_idx;
>>>> -
>>>> -     /* args to ustcomm_send_reply */
>>>> -     struct ustcomm_server server;
>>>> -     struct ustcomm_source src;
>>>> -
>>>> -     /* args to ust_buffers_get_subbuf */
>>>> -     struct ust_buffer *buf;
>>>> -
>>>> -     struct list_head list;
>>>> -};
>>>> -
>>>>  static long long make_pidunique(void)
>>>>  {
>>>>       s64 retval;
>>>> @@ -122,7 +91,12 @@ static void print_markers(FILE *fp)
>>>>       marker_iter_start(&iter);
>>>>
>>>>       while (iter.marker) {
>>>> -             fprintf(fp, "marker: %s/%s %d \"%s\" %p\n",
>>>> iter.marker->channel, iter.marker->name,
>>>> (int)imv_read(iter.marker->state), iter.marker->format,
>>>> iter.marker->location);
>>>> +             fprintf(fp, "marker: %s/%s %d \"%s\" %p\n",
>>>> +                     iter.marker->channel,
>>>> +                     iter.marker->name,
>>>> +                     (int)imv_read(iter.marker->state),
>>>> +                     iter.marker->format,
>>>> +                     iter.marker->location);
>>>>               marker_iter_next(&iter);
>>>>       }
>>>>       unlock_markers();
>>>> @@ -143,8 +117,6 @@ static void print_trace_events(FILE *fp)
>>>>       unlock_trace_events();
>>>>  }
>>>>
>>>> -static int init_socket(void);
>>>> -
>>>>  /* Ask the daemon to collect a trace called trace_name and being
>>>>   * produced by this pid.
>>>>   *
>>>> @@ -179,7 +151,8 @@ static void inform_consumer_daemon(const char
>>>> *trace_name)
>>>>                               }
>>>>                               result = ustcomm_request_consumer(pid,
>>>> buf);
>>>>                               if (result == -1) {
>>>> -                                     WARN("Failed to request
>>>> collection for channel %s. Is the daemon available?",
>>>> trace->channels[i].channel_name);
>>>> +                                     WARN("Failed to request
>>>> collection for channel %s. Is the daemon available?",
>>>> +                                         
>>>> trace->channels[i].channel_name);
>>>>                                       /* continue even if fail */
>>>>                               }
>>>>                               free(buf);
>>>> @@ -192,74 +165,6 @@ static void inform_consumer_daemon(const char
>>>> *trace_name)
>>>>       ltt_unlock_traces();
>>>>  }
>>>>
>>>> -int process_blkd_consumer_act(void *priv, int fd, short events)
>>>> -{
>>>> -     int result;
>>>> -     long consumed_old = 0;
>>>> -     char *reply;
>>>> -     struct blocked_consumer *bc = (struct blocked_consumer *) priv;
>>>> -     char inbuf;
>>>> -
>>>> -     result = read(bc->fd_producer, &inbuf, 1);
>>>> -     if (result == -1) {
>>>> -             PERROR("read");
>>>> -             return -1;
>>>> -     }
>>>> -     if (result == 0) {
>>>> -             int res;
>>>> -             DBG("listener: got messsage that a buffer ended");
>>>> -
>>>> -             res = close(bc->fd_producer);
>>>> -             if (res == -1) {
>>>> -                     PERROR("close");
>>>> -             }
>>>> -
>>>> -             list_del(&bc->list);
>>>> -
>>>> -             result = ustcomm_send_reply(&bc->server, "END", &bc->src);
>>>> -             if (result < 0) {
>>>> -                     ERR("ustcomm_send_reply failed");
>>>> -                     return -1;
>>>> -             }
>>>> -
>>>> -             return 0;
>>>> -     }
>>>> -
>>>> -     result = ust_buffers_get_subbuf(bc->buf, &consumed_old);
>>>> -     if (result == -EAGAIN) {
>>>> -             WARN("missed buffer?");
>>>> -             return 0;
>>>> -     } else if (result < 0) {
>>>> -             ERR("ust_buffers_get_subbuf: error: %s",
>>>> strerror(-result));
>>>> -     }
>>>> -     if (asprintf(&reply, "%s %ld", "OK", consumed_old) < 0) {
>>>> -               ERR("process_blkd_consumer_act : asprintf failed (OK
>>>> %ld)",
>>>> -                consumed_old);
>>>> -               return -1;
>>>> -     }
>>>> -     result = ustcomm_send_reply(&bc->server, reply, &bc->src);
>>>> -     if (result < 0) {
>>>> -             ERR("ustcomm_send_reply failed");
>>>> -             free(reply);
>>>> -             return -1;
>>>> -     }
>>>> -     free(reply);
>>>> -
>>>> -     list_del(&bc->list);
>>>> -
>>>> -     return 0;
>>>> -}
>>>> -
>>>> -void blocked_consumers_add_to_mp(struct mpentries *ent)
>>>> -{
>>>> -     struct blocked_consumer *bc;
>>>> -
>>>> -     list_for_each_entry(bc, &blocked_consumers, list) {
>>>> -             multipoll_add(ent, bc->fd_producer, POLLIN,
>>>> process_blkd_consumer_act, bc, NULL);
>>>> -     }
>>>> -
>>>> -}
>>>> -
>>>>  void seperate_channel_cpu(const char *channel_and_cpu, char
>>>> **channel, int *cpu)
>>>>  {
>>>>       const char *sep;
>>>> @@ -279,7 +184,7 @@ void seperate_channel_cpu(const char
>>>> *channel_and_cpu, char **channel, int *cpu)
>>>>       }
>>>>  }
>>>>
>>>> -static int do_cmd_get_shmid(const char *recvbuf, struct
>>>> ustcomm_source *src)
>>>> +static int do_cmd_get_shmid(const char *recvbuf, int sock)
>>>>  {
>>>>       int retval = 0;
>>>>       struct ust_trace *trace;
>>>> @@ -333,7 +238,7 @@ static int do_cmd_get_shmid(const char *recvbuf,
>>>> struct ustcomm_source *src)
>>>>                               goto free_short_chan_name;
>>>>                       }
>>>>
>>>> -                     result =
>>>> ustcomm_send_reply(&ustcomm_app.server, reply, src);
>>>> +                     result = ustcomm_send_reply(reply, sock);
>>>>                       if (result) {
>>>>                               ERR("ustcomm_send_reply failed");
>>>>                               free(reply);
>>>> @@ -359,7 +264,7 @@ static int do_cmd_get_shmid(const char *recvbuf,
>>>> struct ustcomm_source *src)
>>>>       return retval;
>>>>  }
>>>>
>>>> -static int do_cmd_get_n_subbufs(const char *recvbuf, struct
>>>> ustcomm_source *src)
>>>> +static int do_cmd_get_n_subbufs(const char *recvbuf, int sock)
>>>>  {
>>>>       int retval = 0;
>>>>       struct ust_trace *trace;
>>>> @@ -411,7 +316,7 @@ static int do_cmd_get_n_subbufs(const char
>>>> *recvbuf, struct ustcomm_source *src)
>>>>                               goto free_short_chan_name;
>>>>                       }
>>>>
>>>> -                     result =
>>>> ustcomm_send_reply(&ustcomm_app.server, reply, src);
>>>> +                     result = ustcomm_send_reply(reply, sock);
>>>>                       if (result) {
>>>>                               ERR("ustcomm_send_reply failed");
>>>>                               free(reply);
>>>> @@ -435,7 +340,7 @@ static int do_cmd_get_n_subbufs(const char
>>>> *recvbuf, struct ustcomm_source *src)
>>>>       return retval;
>>>>  }
>>>>
>>>> -static int do_cmd_get_subbuf_size(const char *recvbuf, struct
>>>> ustcomm_source *src)
>>>> +static int do_cmd_get_subbuf_size(const char *recvbuf, int sock)
>>>>  {
>>>>       int retval = 0;
>>>>       struct ust_trace *trace;
>>>> @@ -487,7 +392,7 @@ static int do_cmd_get_subbuf_size(const char
>>>> *recvbuf, struct ustcomm_source *sr
>>>>                               goto free_short_chan_name;
>>>>                       }
>>>>
>>>> -                     result =
>>>> ustcomm_send_reply(&ustcomm_app.server, reply, src);
>>>> +                     result = ustcomm_send_reply(reply, sock);
>>>>                       if (result) {
>>>>                               ERR("ustcomm_send_reply failed");
>>>>                               free(reply);
>>>> @@ -524,7 +429,7 @@ static unsigned int pow2_higher_or_eq(unsigned
>>>> int v)
>>>>               return retval<<1;
>>>>  }
>>>>
>>>> -static int do_cmd_set_subbuf_size(const char *recvbuf, struct
>>>> ustcomm_source *src)
>>>> +static int do_cmd_set_subbuf_size(const char *recvbuf, int sock)
>>>>  {
>>>>       char *channel_slash_size;
>>>>       char *ch_name = NULL;
>>>> @@ -581,7 +486,7 @@ static int do_cmd_set_subbuf_size(const char
>>>> *recvbuf, struct ustcomm_source *sr
>>>>       return retval;
>>>>  }
>>>>
>>>> -static int do_cmd_set_subbuf_num(const char *recvbuf, struct
>>>> ustcomm_source *src)
>>>> +static int do_cmd_set_subbuf_num(const char *recvbuf, int sock)
>>>>  {
>>>>       char *channel_slash_num;
>>>>       char *ch_name = NULL;
>>>> @@ -638,7 +543,102 @@ static int do_cmd_set_subbuf_num(const char
>>>> *recvbuf, struct ustcomm_source *src
>>>>       return retval;
>>>>  }
>>>>
>>>> -static int do_cmd_get_subbuffer(const char *recvbuf, struct
>>>> ustcomm_source *src)
>>>> +static int do_cmd_get_subbuffer(const char *recvbuf, int sock)
>>>> +{
>>>> +     int retval = 0, found = 0;;
>>>> +     int i, ch_cpu, result;
>>>> +     long consumed_old = 0;
>>>> +     struct ust_trace *trace;
>>>> +     char trace_name[] = "auto";
>>>> +     char *channel_and_cpu;
>>>> +     char *ch_name;
>>>> +
>>>> +     DBG("get_subbuf");
>>>> +
>>>> +     channel_and_cpu = nth_token(recvbuf, 1);
>>>> +     if(channel_and_cpu == NULL) {
>>>> +             ERR("cannot parse channel");
>>>> +             retval = -1;
>>>> +             goto end;
>>>> +     }
>>>> +
>>>> +     seperate_channel_cpu(channel_and_cpu, &ch_name, &ch_cpu);
>>>> +     if(ch_cpu == -1) {
>>>> +             ERR("problem parsing channel name");
>>>> +             retval = -1;
>>>> +             goto free_short_chan_name;
>>>> +     }
>>>> +
>>>> +     ltt_lock_traces();
>>>> +     trace = _ltt_trace_find(trace_name);
>>>> +
>>>> +     if(trace == NULL) {
>>>> +             int result;
>>>> +
>>>> +             DBG("Cannot find trace. It was likely destroyed by the
>>>> user.");
>>>> +             result = ustcomm_send_reply("NOTFOUND", sock);
>>>> +             if(result) {
>>>> +                     ERR("ustcomm_send_reply failed");
>>>> +                     retval = -1;
>>>> +                     goto unlock_traces;
>>>> +             }
>>>> +
>>>> +             goto unlock_traces;
>>>> +     }
>>>> +
>>>> +     for(i=0; i<trace->nr_channels; i++) {
>>>> +             struct ust_channel *channel = &trace->channels[i];
>>>> +
>>>> +             if(!strcmp(trace->channels[i].channel_name, ch_name)) {
>>>> +                     struct ust_buffer *buf = channel->buf[ch_cpu];
>>>> +                     char *reply;
>>>> +
>>>> +                     found = 1;
>>>> +
>>>> +                     result = ust_buffers_get_subbuf(buf,
>>>> &consumed_old);
>>>> +                     if(result == -EAGAIN) {
>>>> +                             WARN("missed buffer?");
>>>> +                             return 0;
>>>> +                     } else if (result < 0) {
>>>> +                             ERR("ust_buffers_get_subbuf: error:
>>>> %s", strerror(-result));
>>>> +                     }
>>>> +                     if (asprintf(&reply, "%s %ld", "OK",
>>>> consumed_old) < 0) {
>>>> +                             ERR("process_blkd_consumer_act :
>>>> asprintf failed (OK %ld)",
>>>> +                                 consumed_old);
>>>> +                             return -1;
>>>> +                     }
>>>> +                     result = ustcomm_send_reply(reply, sock);
>>>> +                     if (result < 0) {
>>>> +                             ERR("ustcomm_send_reply failed");
>>>> +                             free(reply);
>>>> +                             return -1;
>>>> +                     }
>>>> +                     free(reply);
>>>> +
>>>> +                     break;
>>>> +             }
>>>> +     }
>>>> +     if(found == 0) {
>>>> +             result = ustcomm_send_reply("NOTFOUND", sock);
>>>> +             if (result <= 0) {
>>>> +                     ERR("ustcomm_send_reply failed");
>>>> +                     return -1;
>>>> +             }
>>>> +             ERR("unable to find channel");
>>>> +     }
>>>> +
>>>> +     unlock_traces:
>>>> +     ltt_unlock_traces();
>>>> +
>>>> +     free_short_chan_name:
>>>> +     free(ch_name);
>>>> +
>>>> +     end:
>>>> +     return retval;
>>>> +}
>>>> +
>>>> +
>>>> +static int do_cmd_get_buffer_fd(const char *recvbuf, int sock)
>>>>  {
>>>>       int retval = 0;
>>>>       struct ust_trace *trace;
>>>> @@ -648,8 +648,9 @@ static int do_cmd_get_subbuffer(const char
>>>> *recvbuf, struct ustcomm_source *src)
>>>>       int found = 0;
>>>>       char *ch_name;
>>>>       int ch_cpu;
>>>> +     struct ustcomm_header header;
>>>>
>>>> -     DBG("get_subbuf");
>>>> +     DBG("get_buffer_fd");
>>>>
>>>>       channel_and_cpu = nth_token(recvbuf, 1);
>>>>       if (channel_and_cpu == NULL) {
>>>> @@ -672,7 +673,7 @@ static int do_cmd_get_subbuffer(const char
>>>> *recvbuf, struct ustcomm_source *src)
>>>>               int result;
>>>>
>>>>               DBG("Cannot find trace. It was likely destroyed by the
>>>> user.");
>>>> -             result = ustcomm_send_reply(&ustcomm_app.server,
>>>> "NOTFOUND", src);
>>>> +             result = ustcomm_send_reply("NOTFOUND", sock);
>>>>               if (result) {
>>>>                       ERR("ustcomm_send_reply failed");
>>>>                       retval = -1;
>>>> @@ -687,22 +688,16 @@ static int do_cmd_get_subbuffer(const char
>>>> *recvbuf, struct ustcomm_source *src)
>>>>
>>>>               if (!strcmp(trace->channels[i].channel_name, ch_name)) {
>>>>                       struct ust_buffer *buf = channel->buf[ch_cpu];
>>>> -                     struct blocked_consumer *bc;
>>>>
>>>>                       found = 1;
>>>>
>>>> -                     bc = (struct blocked_consumer *)
>>>> zmalloc(sizeof(struct blocked_consumer));
>>>> -                     if (bc == NULL) {
>>>> -                             ERR("zmalloc returned NULL");
>>>> +                     header.size = 0;
>>>> +                     header.fd_included = 1;
>>>> +                     if (ustcomm_send_fd(sock, &header, NULL,
>>>> +                                         &buf->data_ready_fd_read)
>>>> <= 0) {
>>>> +                             ERR("ustcomm_send_fd failed\n");
>>>>                               goto unlock_traces;
>>>>                       }
>>>> -                     bc->fd_consumer = src->fd;
>>>> -                     bc->fd_producer = buf->data_ready_fd_read;
>>>> -                     bc->buf = buf;
>>>> -                     bc->src = *src;
>>>> -                     bc->server = ustcomm_app.server;
>>>> -
>>>> -                     list_add(&bc->list, &blocked_consumers);
>>>>
>>>>                       /* Being here is the proof the daemon has
>>>> mapped the buffer in its
>>>>                        * memory. We may now decrement buffers_to_export.
>>>> @@ -712,6 +707,10 @@ static int do_cmd_get_subbuffer(const char
>>>> *recvbuf, struct ustcomm_source *src)
>>>>                               STORE_SHARED(buffers_to_export,
>>>> LOAD_SHARED(buffers_to_export)-1);
>>>>                       }
>>>>
>>>> +                     /* The buffer has been exported, ergo, we can
>>>> add it to the
>>>> +                      * list of open buffers
>>>> +                      */
>>>> +                     list_add(&buf->open_buffers_list,
>>>> &open_buffers_list);
>>>>                       break;
>>>>               }
>>>>       }
>>>> @@ -729,7 +728,7 @@ static int do_cmd_get_subbuffer(const char
>>>> *recvbuf, struct ustcomm_source *src)
>>>>       return retval;
>>>>  }
>>>>
>>>> -static int do_cmd_put_subbuffer(const char *recvbuf, struct
>>>> ustcomm_source *src)
>>>> +static int do_cmd_put_subbuffer(const char *recvbuf, int sock)
>>>>  {
>>>>       int retval = 0;
>>>>       struct ust_trace *trace;
>>>> @@ -779,7 +778,7 @@ static int do_cmd_put_subbuffer(const char
>>>> *recvbuf, struct ustcomm_source *src)
>>>>
>>>>       if (trace == NULL) {
>>>>               DBG("Cannot find trace. It was likely destroyed by the
>>>> user.");
>>>> -             result = ustcomm_send_reply(&ustcomm_app.server,
>>>> "NOTFOUND", src);
>>>> +             result = ustcomm_send_reply("NOTFOUND", sock);
>>>>               if (result) {
>>>>                       ERR("ustcomm_send_reply failed");
>>>>                       retval = -1;
>>>> @@ -814,7 +813,7 @@ static int do_cmd_put_subbuffer(const char
>>>> *recvbuf, struct ustcomm_source *src)
>>>>                               }
>>>>                       }
>>>>
>>>> -                     result =
>>>> ustcomm_send_reply(&ustcomm_app.server, reply, src);
>>>> +                     result = ustcomm_send_reply(reply, sock);
>>>>                       if (result) {
>>>>                               ERR("ustcomm_send_reply failed");
>>>>                               free(reply);
>>>> @@ -845,26 +844,26 @@ static int do_cmd_put_subbuffer(const char
>>>> *recvbuf, struct ustcomm_source *src)
>>>>
>>>>  static void listener_cleanup(void *ptr)
>>>>  {
>>>> -     ustcomm_fini_app(&ustcomm_app, 0);
>>>> +     ustcomm_del_named_sock(listen_sock, 0);
>>>>  }
>>>>
>>>>  static void do_cmd_force_switch()
>>>>  {
>>>> -     struct blocked_consumer *bc;
>>>> +     struct ust_buffer *buf;
>>>>
>>>> -     list_for_each_entry(bc, &blocked_consumers, list) {
>>>> -             ltt_force_switch(bc->buf, FORCE_FLUSH);
>>>> +     list_for_each_entry(buf, &open_buffers_list,
>>>> +                         open_buffers_list) {
>>>> +             ltt_force_switch(buf, FORCE_FLUSH);
>>>>       }
>>>>  }
>>>>
>>>> -int process_client_cmd(char *recvbuf, struct ustcomm_source *src)
>>>> +static int process_client_cmd(char *recvbuf, int sock)
>>>>  {
>>>>       int result;
>>>>       char trace_name[] = "auto";
>>>>       char trace_type[] = "ustrelay";
>>>>       int len;
>>>>
>>>> -     DBG("received a message! it's: %s", recvbuf);
>>>>       len = strlen(recvbuf);
>>>>
>>>>       if (!strcmp(recvbuf, "print_markers")) {
>>>> @@ -878,7 +877,7 @@ int process_client_cmd(char *recvbuf, struct
>>>> ustcomm_source *src)
>>>>               print_markers(fp);
>>>>               fclose(fp);
>>>>
>>>> -             result = ustcomm_send_reply(&ustcomm_app.server, ptr,
>>>> src);
>>>> +             result = ustcomm_send_reply(ptr, sock);
>>>>
>>>>               free(ptr);
>>>>       } else if (!strcmp(recvbuf, "print_trace_events")) {
>>>> @@ -897,7 +896,7 @@ int process_client_cmd(char *recvbuf, struct
>>>> ustcomm_source *src)
>>>>               print_trace_events(fp);
>>>>               fclose(fp);
>>>>
>>>> -             result = ustcomm_send_reply(&ustcomm_app.server, ptr,
>>>> src);
>>>> +             result = ustcomm_send_reply(ptr, sock);
>>>>               if (result < 0) {
>>>>                       ERR("list_trace_events failed");
>>>>                       return -1;
>>>> @@ -1002,11 +1001,11 @@ int process_client_cmd(char *recvbuf, struct
>>>> ustcomm_source *src)
>>>>                       return -1;
>>>>               }
>>>>       } else if (nth_token_is(recvbuf, "get_shmid", 0) == 1) {
>>>> -             do_cmd_get_shmid(recvbuf, src);
>>>> +             do_cmd_get_shmid(recvbuf, sock);
>>>>       } else if (nth_token_is(recvbuf, "get_n_subbufs", 0) == 1) {
>>>> -             do_cmd_get_n_subbufs(recvbuf, src);
>>>> +             do_cmd_get_n_subbufs(recvbuf, sock);
>>>>       } else if (nth_token_is(recvbuf, "get_subbuf_size", 0) == 1) {
>>>> -             do_cmd_get_subbuf_size(recvbuf, src);
>>>> +             do_cmd_get_subbuf_size(recvbuf, sock);
>>>>       } else if (nth_token_is(recvbuf, "load_probe_lib", 0) == 1) {
>>>>               char *libfile;
>>>>
>>>> @@ -1016,13 +1015,17 @@ int process_client_cmd(char *recvbuf, struct
>>>> ustcomm_source *src)
>>>>
>>>>               free(libfile);
>>>>       } else if (nth_token_is(recvbuf, "get_subbuffer", 0) == 1) {
>>>> -             do_cmd_get_subbuffer(recvbuf, src);
>>>> -     } else if (nth_token_is(recvbuf, "put_subbuffer", 0) == 1) {
>>>> -             do_cmd_put_subbuffer(recvbuf, src);
>>>> +             do_cmd_get_subbuffer(recvbuf, sock);
>>>> +     }
>>>> +     else if(nth_token_is(recvbuf, "get_buffer_fd", 0) == 1) {
>>>> +             do_cmd_get_buffer_fd(recvbuf, sock);
>>>> +     }
>>>> +     else if(nth_token_is(recvbuf, "put_subbuffer", 0) == 1) {
>>>> +             do_cmd_put_subbuffer(recvbuf, sock);
>>>>       } else if (nth_token_is(recvbuf, "set_subbuf_size", 0) == 1) {
>>>> -             do_cmd_set_subbuf_size(recvbuf, src);
>>>> +             do_cmd_set_subbuf_size(recvbuf, sock);
>>>>       } else if (nth_token_is(recvbuf, "set_subbuf_num", 0) == 1) {
>>>> -             do_cmd_set_subbuf_num(recvbuf, src);
>>>> +             do_cmd_set_subbuf_num(recvbuf, sock);
>>>>       } else if (nth_token_is(recvbuf, "enable_marker", 0) == 1) {
>>>>               char *channel_slash_name = nth_token(recvbuf, 1);
>>>>               char *channel_name = NULL;
>>>> @@ -1074,7 +1077,7 @@ int process_client_cmd(char *recvbuf, struct
>>>> ustcomm_source *src)
>>>>                       goto next_cmd;
>>>>               }
>>>>
>>>> -             result = ustcomm_send_reply(&ustcomm_app.server, reply,
>>>> src);
>>>> +             result = ustcomm_send_reply(reply, sock);
>>>>               if (result) {
>>>>                       ERR("listener: get_pidunique:
>>>> ustcomm_send_reply failed");
>>>>                       goto next_cmd;
>>>> @@ -1089,10 +1092,10 @@ int process_client_cmd(char *recvbuf, struct
>>>> ustcomm_source *src)
>>>>                                   SOCK_DIR);
>>>>                               goto next_cmd;
>>>>                       }
>>>> -                     result =
>>>> ustcomm_send_reply(&ustcomm_app.server, reply, src);
>>>> +                     result = ustcomm_send_reply(reply, sock);
>>>>                       free(reply);
>>>>               } else {
>>>> -                     result =
>>>> ustcomm_send_reply(&ustcomm_app.server, reply, src);
>>>> +                     result = ustcomm_send_reply(reply, sock);
>>>>               }
>>>>               if (result)
>>>>                       ERR("ustcomm_send_reply failed");
>>>> @@ -1112,28 +1115,54 @@ next_cmd:
>>>>       return 0;
>>>>  }
>>>>
>>>> +
>>>> +
>>>> +
>>>> +#define MAX_EVENTS 10
>>>> +
>>>> +
>>>> +
>>>>  void *listener_main(void *p)
>>>>  {
>>>> -     int result;
>>>> +     struct ustcomm_sock *epoll_sock;
>>>> +     struct epoll_event events[MAX_EVENTS];
>>>> +     struct sockaddr addr;
>>>> +     int accept_fd, nfds, result, i, addr_size;
>>>>
>>>>       DBG("LISTENER");
>>>>
>>>>       pthread_cleanup_push(listener_cleanup, NULL);
>>>>
>>>> -     for (;;) {
>>>> -             struct mpentries mpent;
>>>> -
>>>> -             multipoll_init(&mpent);
>>>> -
>>>> -             blocked_consumers_add_to_mp(&mpent);
>>>> -             ustcomm_mp_add_app_clients(&mpent, &ustcomm_app,
>>>> process_client_cmd);
>>>> -
>>>> -             result = multipoll_poll(&mpent, -1);
>>>> -             if (result == -1) {
>>>> -                     ERR("error in multipoll_poll");
>>>> +     for(;;) {
>>>> +             nfds = epoll_wait(epoll_fd, events, MAX_EVENTS, -1);
>>>> +             if (nfds == -1) {
>>>> +                     ERR("epoll_wait");
>>>> +                     continue;
>>>>               }
>>>>
>>>> -             multipoll_destroy(&mpent);
>>>> +             for (i = 0; i < nfds; i++) {
>>>> +                     epoll_sock = (struct ustcomm_sock
>>>> *)events[i].data.ptr;
>>>> +                     if (epoll_sock == listen_sock) {
>>>> +                             addr_size = sizeof(struct sockaddr);
>>>> +                             accept_fd = accept(epoll_sock->fd,
>>>> +                                                &addr,
>>>> +                                                (socklen_t
>>>> *)&addr_size);
>>>> +                             if (accept_fd == -1) {
>>>> +                                     ERR("accept failed\n");
>>>> +                             }
>>>> +                             ustcomm_init_sock(accept_fd, epoll_fd,
>>>> +                                              &ust_socks);
>>>> +                     } else {
>>>> +                             char *msg = NULL;
>>>> +                             result =
>>>> recv_message_conn(epoll_sock->fd, &msg);
>>>> +                             if (result == 0) {
>>>> +                                     ustcomm_del_sock(epoll_sock, 0);
>>>> +                             } else if (msg) {
>>>> +                                     process_client_cmd(msg,
>>>> epoll_sock->fd);
>>>> +                                     free(msg);
>>>> +                             }
>>>> +                     }
>>>> +             }
>>>>       }
>>>>
>>>>       pthread_cleanup_pop(1);
>>>> @@ -1183,11 +1212,6 @@ void create_listener(void)
>>>>       }
>>>>  }
>>>>
>>>> -static int init_socket(void)
>>>> -{
>>>> -     return ustcomm_init_app(getpid(), &ustcomm_app);
>>>> -}
>>>> -
>>>>  #define AUTOPROBE_DISABLED      0
>>>>  #define AUTOPROBE_ENABLE_ALL    1
>>>>  #define AUTOPROBE_ENABLE_REGEX  2
>>>> @@ -1225,6 +1249,41 @@ static void auto_probe_connect(struct marker *m)
>>>>
>>>>  }
>>>>
>>>> +static struct ustcomm_sock * init_app_socket(int epoll_fd)
>>>> +{
>>>> +     char *name;
>>>> +     int result;
>>>> +     struct ustcomm_sock *sock;
>>>> +
>>>> +     result = asprintf(&name, "%s/%d", SOCK_DIR, (int)getpid());
>>>> +     if (result < 0) {
>>>> +             ERR("string overflow allocating socket name, "
>>>> +                 "UST thread bailing");
>>>> +             return NULL;
>>>> +     }
>>>> +
>>>> +     result = ensure_dir_exists(SOCK_DIR);
>>>> +     if (result == -1) {
>>>> +             ERR("Unable to create socket directory %s, UST thread
>>>> bailing",
>>>> +                 SOCK_DIR);
>>>> +             goto free_name;
>>>> +     }
>>>> +
>>>> +     sock = ustcomm_init_named_socket(name, epoll_fd);
>>>> +     if (!sock) {
>>>> +             ERR("Error initializing named socket (%s). Check that
>>>> directory"
>>>> +                 "exists and that it is writable. UST thread
>>>> bailing", name);
>>>> +             goto free_name;
>>>> +     }
>>>> +
>>>> +     free(name);
>>>> +     return sock;
>>>> +
>>>> +free_name:
>>>> +     free(name);
>>>> +     return NULL;
>>>> +}
>>>> +
>>>>  static void __attribute__((constructor)) init()
>>>>  {
>>>>       int result;
>>>> @@ -1242,9 +1301,18 @@ static void __attribute__((constructor)) init()
>>>>
>>>>       DBG("Tracectl constructor");
>>>>
>>>> -     result = init_socket();
>>>> -     if (result == -1) {
>>>> -             ERR("init_socket error");
>>>> +     /* Set up epoll */
>>>> +     epoll_fd = epoll_create(MAX_EVENTS);
>>>> +     if (epoll_fd == -1) {
>>>> +             ERR("epoll_create failed, tracing shutting down");
>>>> +             return;
>>>> +     }
>>>> +
>>>> +     /* Create the socket */
>>>> +     listen_sock = init_app_socket(epoll_fd);
>>>> +     if (!listen_sock) {
>>>> +             ERR("failed to create application socket,"
>>>> +                 " tracing shutting down");
>>>>               return;
>>>>       }
>>>>
>>>> @@ -1451,13 +1519,6 @@ static int trace_recording(void)
>>>>       return retval;
>>>>  }
>>>>
>>>> -#if 0
>>>> -static int have_consumer(void)
>>>> -{
>>>> -     return !list_empty(&blocked_consumers);
>>>> -}
>>>> -#endif
>>>> -
>>>>  int restarting_usleep(useconds_t usecs)
>>>>  {
>>>>          struct timespec tv;
>>>> @@ -1545,8 +1606,8 @@ void ust_potential_exec(void)
>>>>
>>>>  static void ust_fork(void)
>>>>  {
>>>> -     struct blocked_consumer *bc;
>>>> -     struct blocked_consumer *deletable_bc = NULL;
>>>> +     struct ust_buffer *buf, *buf_tmp;
>>>> +     struct ustcomm_sock *sock, *sock_tmp;
>>>>       int result;
>>>>
>>>>       /* FIXME: technically, the locks could have been taken before
>>>> the fork */
>>>> @@ -1557,26 +1618,47 @@ static void ust_fork(void)
>>>>
>>>>       ltt_trace_stop("auto");
>>>>       ltt_trace_destroy("auto", 1);
>>>> -     /* Delete all active connections */
>>>> -     ustcomm_close_all_connections(&ustcomm_app.server);
>>>> +     /* Delete all active connections, but leave them in the epoll
>>>> set */
>>>> +     list_for_each_entry_safe(sock, sock_tmp, &ust_socks, list) {
>>>> +             ustcomm_del_sock(sock, 1);
>>>> +     }
>>>>
>>>>       /* Delete all blocked consumers */
>>>> -     list_for_each_entry(bc, &blocked_consumers, list) {
>>>> -             result = close(bc->fd_producer);
>>>> -             if (result == -1) {
>>>> +     list_for_each_entry_safe(buf, buf_tmp, &open_buffers_list,
>>>> +                              open_buffers_list) {
>>>> +             result = close(buf->data_ready_fd_read);
>>>> +             if(result == -1) {
>>>>                       PERROR("close");
>>>>               }
>>>> -             free(deletable_bc);
>>>> -             deletable_bc = bc;
>>>> -             list_del(&bc->list);
>>>> +             result = close(buf->data_ready_fd_write);
>>>> +             if(result == -1) {
>>>> +                     PERROR("close");
>>>> +             }
>>>> +             list_del(&buf->open_buffers_list);
>>>>       }
>>>>
>>>> -     /* free app, keeping socket file */
>>>> -     ustcomm_fini_app(&ustcomm_app, 1);
>>>> +     /* Clean up the listener socket and epoll, keeping the scoket
>>>> file */
>>>> +     ustcomm_del_named_sock(listen_sock, 1);
>>>> +     close(epoll_fd);
>>>>
>>>> +     /* Re-start the launch sequence */
>>>>       STORE_SHARED(buffers_to_export, 0);
>>>>       have_listener = 0;
>>>> -     init_socket();
>>>> +
>>>> +     /* Set up epoll */
>>>> +     epoll_fd = epoll_create(MAX_EVENTS);
>>>> +     if (epoll_fd == -1) {
>>>> +             ERR("epoll_create failed, tracing shutting down");
>>>> +             return;
>>>> +     }
>>>> +
>>>> +     /* Create the socket */
>>>> +     listen_sock = init_app_socket(epoll_fd);
>>>> +     if (!listen_sock) {
>>>> +             ERR("failed to create application socket,"
>>>> +                 " tracing shutting down");
>>>> +             return;
>>>> +     }
>>>>       create_listener();
>>>>       ltt_trace_setup("auto");
>>>>       result = ltt_trace_set_type("auto", "ustrelay");
>>>> diff --git a/libustcmd/ustcmd.c b/libustcmd/ustcmd.c
>>>> index c512320..ac90f6c 100644
>>>> --- a/libustcmd/ustcmd.c
>>>> +++ b/libustcmd/ustcmd.c
>>>> @@ -52,7 +52,12 @@ pid_t *ustcmd_get_online_pids(void)
>>>>                       !!strcmp(dirent->d_name, "ustd")) {
>>>>
>>>>                       sscanf(dirent->d_name, "%u", (unsigned int *)
>>>> &ret[i]);
>>>> -                     if (pid_is_online(ret[i])) {
>>>> +                     /* FIXME: Here we previously called
>>>> pid_is_online, which
>>>> +                      * always returned 1, now I replaced it with
>>>> just 1.
>>>> +                      * We need to figure out an intelligent way of
>>>> solving
>>>> +                      * this, maybe connect-disconnect.
>>>> +                      */
>>>> +                     if (1) {
>>>>                               ret_size += sizeof(pid_t);
>>>>                               ret = (pid_t *) realloc(ret, ret_size);
>>>>                               ++i;
>>>> @@ -592,17 +597,17 @@ int ustcmd_force_switch(pid_t pid)
>>>>
>>>>  int ustcmd_send_cmd(const char *cmd, const pid_t pid, char **reply)
>>>>  {
>>>> -     struct ustcomm_connection conn;
>>>> +     int app_fd;
>>>>       int retval;
>>>>
>>>> -     if (ustcomm_connect_app(pid, &conn)) {
>>>> +     if (ustcomm_connect_app(pid, &app_fd)) {
>>>>               ERR("could not connect to PID %u", (unsigned int) pid);
>>>>               return -1;
>>>>       }
>>>>
>>>> -     retval = ustcomm_send_request(&conn, cmd, reply);
>>>> +     retval = ustcomm_send_request(app_fd, cmd, reply);
>>>>
>>>> -     ustcomm_close_app(&conn);
>>>> +     close(app_fd);
>>>>
>>>>       return retval;
>>>>  }
>>>> diff --git a/libustcomm/Makefile.am b/libustcomm/Makefile.am
>>>> index 2672071..3ae96d5 100644
>>>> --- a/libustcomm/Makefile.am
>>>> +++ b/libustcomm/Makefile.am
>>>> @@ -4,8 +4,7 @@ AM_CFLAGS = -fno-strict-aliasing
>>>>  noinst_LTLIBRARIES = libustcomm.la
>>>>  libustcomm_la_SOURCES = \
>>>>       ustcomm.h \
>>>> -     ustcomm.c \
>>>> -     multipoll.h \
>>>> -     multipoll.c
>>>> +     ustcomm.c
>>>> +
>>>>  libustcomm_la_LDFLAGS = -no-undefined -static
>>>>  libustcomm_la_CFLAGS = -DUST_COMPONENT="libustcomm" -fPIC
>>>> -fno-strict-aliasing
>>>> diff --git a/libustcomm/multipoll.c b/libustcomm/multipoll.c
>>>> deleted file mode 100644
>>>> index 80426e3..0000000
>>>> --- a/libustcomm/multipoll.c
>>>> +++ /dev/null
>>>> @@ -1,130 +0,0 @@
>>>> -/*
>>>> - * multipoll.c
>>>> - *
>>>> - * Copyright (C) 2010 - Pierre-Marc Fournier (pierre-marc dot
>>>> fournier at polymtl dot ca)
>>>> - *
>>>> - * This library is free software; you can redistribute it and/or
>>>> - * modify it under the terms of the GNU Lesser General Public
>>>> - * License as published by the Free Software Foundation; either
>>>> - * version 2.1 of the License, or (at your option) any later version.
>>>> - *
>>>> - * This library 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
>>>> - * Lesser General Public License for more details.
>>>> - *
>>>> - * You should have received a copy of the GNU Lesser General Public
>>>> - * License along with this library; if not, write to the Free Software
>>>> - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 
>>>> 02110-1301 USA
>>>> - */
>>>> -
>>>> -/* Multipoll is a framework to poll on several file descriptors and
>>>> to call
>>>> - * a specific callback depending on the fd that had activity.
>>>> - */
>>>> -
>>>> -#include <poll.h>
>>>> -#include <stdlib.h>
>>>> -#include "multipoll.h"
>>>> -#include "usterr.h"
>>>> -
>>>> -#define INITIAL_N_AVAIL 16
>>>> -
>>>> -/* multipoll_init
>>>> - *
>>>> - * Initialize an mpentries struct, which is initially empty of any fd.
>>>> - */
>>>> -
>>>> -int multipoll_init(struct mpentries *ent)
>>>> -{
>>>> -     ent->n_used = 0;
>>>> -     ent->n_avail = INITIAL_N_AVAIL;
>>>> -
>>>> -     ent->pollfds = (struct pollfd *) zmalloc(sizeof(struct pollfd)
>>>> * INITIAL_N_AVAIL);
>>>> -     ent->extras = (struct pollfd_extra *) zmalloc(sizeof(struct
>>>> pollfd_extra) * INITIAL_N_AVAIL);
>>>> -
>>>> -     return 0;
>>>> -}
>>>> -
>>>> -/* multipoll_destroy: free a struct mpentries
>>>> - */
>>>> -
>>>> -int multipoll_destroy(struct mpentries *ent)
>>>> -{
>>>> -     int i;
>>>> -
>>>> -     for(i=0; i<ent->n_used; i++) {
>>>> -             if(ent->extras[i].destroy_priv) {
>>>> -                     ent->extras[i].destroy_priv(ent->extras[i].priv);
>>>> -             }
>>>> -     }
>>>> -
>>>> -     free(ent->pollfds);
>>>> -     free(ent->extras);
>>>> -
>>>> -     return 0;
>>>> -}
>>>> -
>>>> -/* multipoll_add
>>>> - *
>>>> - * Add a file descriptor to be waited on in a struct mpentries.
>>>> - *
>>>> - * @ent: the struct mpentries to add an fd to
>>>> - * @fd: the fd to wait on
>>>> - * @events: a mask of the types of events to wait on, see the
>>>> poll(2) man page
>>>> - * @func: the callback function to be called if there is activity on
>>>> the fd
>>>> - * @priv: the private pointer to pass to func
>>>> - * @destroy_priv: a callback to destroy the priv pointer when the
>>>> mpentries
>>>> -                  is destroyed; may be NULL
>>>> - */
>>>> -
>>>> -int multipoll_add(struct mpentries *ent, int fd, short events, int
>>>> (*func)(void *priv, int fd, short events), void *priv, int
>>>> (*destroy_priv)(void *))
>>>> -{
>>>> -     int cur;
>>>> -
>>>> -     if(ent->n_used == ent->n_avail) {
>>>> -             ent->n_avail *= 2;
>>>> -             ent->pollfds = (struct pollfd *) realloc(ent->pollfds,
>>>> sizeof(struct pollfd) * ent->n_avail);
>>>> -             ent->extras = (struct pollfd_extra *)
>>>> realloc(ent->extras, sizeof(struct pollfd_extra) * ent->n_avail);
>>>> -     }
>>>> -
>>>> -     cur = ent->n_used;
>>>> -     ent->n_used++;
>>>> -
>>>> -     ent->pollfds[cur].fd = fd;
>>>> -     ent->pollfds[cur].events = events;
>>>> -     ent->extras[cur].func = func;
>>>> -     ent->extras[cur].priv = priv;
>>>> -     ent->extras[cur].destroy_priv = destroy_priv;
>>>> -
>>>> -     return 0;
>>>> -}
>>>> -
>>>> -/* multipoll_poll: do the actual poll on a struct mpentries
>>>> - *
>>>> - * File descriptors should have been already added with
>>>> multipoll_add().
>>>> - *
>>>> - * A struct mpentries may be reused for multiple multipoll_poll calls.
>>>> - *
>>>> - * @ent: the struct mpentries to poll on.
>>>> - * @timeout: the timeout after which to return if there was no
>>>> activity.
>>>> - */
>>>> -
>>>> -int multipoll_poll(struct mpentries *ent, int timeout)
>>>> -{
>>>> -     int result;
>>>> -     int i;
>>>> -
>>>> -     result = poll(ent->pollfds, ent->n_used, timeout);
>>>> -     if(result == -1) {
>>>> -             PERROR("poll");
>>>> -             return -1;
>>>> -     }
>>>> -
>>>> -     for(i=0; i<ent->n_used; i++) {
>>>> -             if(ent->pollfds[i].revents) {
>>>> -                     ent->extras[i].func(ent->extras[i].priv,
>>>> ent->pollfds[i].fd, ent->pollfds[i].revents);
>>>> -             }
>>>> -     }
>>>> -
>>>> -     return 0;
>>>> -}
>>>> diff --git a/libustcomm/multipoll.h b/libustcomm/multipoll.h
>>>> deleted file mode 100644
>>>> index 8a0124f..0000000
>>>> --- a/libustcomm/multipoll.h
>>>> +++ /dev/null
>>>> @@ -1,44 +0,0 @@
>>>> -/*
>>>> - * multipoll.h
>>>> - *
>>>> - * Copyright (C) 2010 - Pierre-Marc Fournier (pierre-marc dot
>>>> fournier at polymtl dot ca)
>>>> - *
>>>> - * This library is free software; you can redistribute it and/or
>>>> - * modify it under the terms of the GNU Lesser General Public
>>>> - * License as published by the Free Software Foundation; either
>>>> - * version 2.1 of the License, or (at your option) any later version.
>>>> - *
>>>> - * This library 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
>>>> - * Lesser General Public License for more details.
>>>> - *
>>>> - * You should have received a copy of the GNU Lesser General Public
>>>> - * License along with this library; if not, write to the Free Software
>>>> - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 
>>>> 02110-1301 USA
>>>> - */
>>>> -
>>>> -#ifndef UST_MULTIPOLL_H
>>>> -#define UST_MULTIPOLL_H
>>>> -
>>>> -struct pollfd_extra {
>>>> -     int (*func)(void *priv, int fd, short events);
>>>> -     void *priv;
>>>> -
>>>> -     int (*destroy_priv)(void *priv);
>>>> -};
>>>> -
>>>> -struct mpentries {
>>>> -     struct pollfd *pollfds;
>>>> -     struct pollfd_extra *extras;
>>>> -
>>>> -     int n_used;
>>>> -     int n_avail;
>>>> -};
>>>> -
>>>> -extern int multipoll_init(struct mpentries *ent);
>>>> -extern int multipoll_add(struct mpentries *ent, int fd, short
>>>> events, int (*func)(void *priv, int fd, short events), void *priv,
>>>> int (*destroy_priv)(void *));
>>>> -extern int multipoll_destroy(struct mpentries *ent);
>>>> -extern int multipoll_poll(struct mpentries *ent, int timeout);
>>>> -
>>>> -#endif /* UST_MULTIPOLL_H */
>>>> diff --git a/libustcomm/ustcomm.c b/libustcomm/ustcomm.c
>>>> index 567c5d1..d55ac4c 100644
>>>> --- a/libustcomm/ustcomm.c
>>>> +++ b/libustcomm/ustcomm.c
>>>> @@ -25,6 +25,7 @@
>>>>  #include <sys/un.h>
>>>>  #include <unistd.h>
>>>>  #include <poll.h>
>>>> +#include <sys/epoll.h>
>>>>  #include <sys/stat.h>
>>>>
>>>>  #include <stdio.h>
>>>> @@ -35,9 +36,6 @@
>>>>  #include "ustcomm.h"
>>>>  #include "usterr.h"
>>>>  #include "share.h"
>>>> -#include "multipoll.h"
>>>> -
>>>> -#define UNIX_PATH_MAX 108
>>>>
>>>>  static int mkdir_p(const char *path, mode_t mode)
>>>>  {
>>>> @@ -91,430 +89,450 @@ static int mkdir_p(const char *path, mode_t mode)
>>>>       return retval;
>>>>  }
>>>>
>>>> -static int signal_process(pid_t pid)
>>>> +static struct sockaddr_un * create_sock_addr(const char *name,
>>>> +                                          size_t *sock_addr_size)
>>>>  {
>>>> -     return 0;
>>>> -}
>>>> +     struct sockaddr_un * addr;
>>>> +     size_t alloc_size;
>>>>
>>>> -void ustcomm_init_connection(struct ustcomm_connection *conn)
>>>> -{
>>>> -     conn->recv_buf = NULL;
>>>> -     conn->recv_buf_size = 0;
>>>> -     conn->recv_buf_alloc = 0;
>>>> -}
>>>> +     alloc_size = (size_t) (((struct sockaddr_un *) 0)->sun_path) +
>>>> +             strlen(name) + 1;
>>>>
>>>> -int pid_is_online(pid_t pid) {
>>>> -     return 1;
>>>> -}
>>>> +     addr = malloc(alloc_size);
>>>> +     if (addr < 0) {
>>>> +             ERR("allocating addr failed");
>>>> +             return NULL;
>>>> +     }
>>>>
>>>> -/* Send a message
>>>> - *
>>>> - * @fd: file descriptor to send to
>>>> - * @msg: a null-terminated string containing the message to send
>>>> - *
>>>> - * Return value:
>>>> - * -1: error
>>>> - * 0: connection closed
>>>> - * 1: success
>>>> - */
>>>> +     addr->sun_family = AF_UNIX;
>>>> +     strcpy(addr->sun_path, name);
>>>> +
>>>> +     *sock_addr_size = alloc_size;
>>>> +
>>>> +     return addr;
>>>> +}
>>>>
>>>> -static int send_message_fd(int fd, const char *msg)
>>>> +struct ustcomm_sock * ustcomm_init_sock(int fd, int epoll_fd,
>>>> +                                     struct list_head *list)
>>>>  {
>>>> -     int result;
>>>> +     struct epoll_event ev;
>>>> +     struct ustcomm_sock *sock;
>>>>
>>>> -     /* Send including the final \0 */
>>>> -     result = patient_send(fd, msg, strlen(msg)+1, MSG_NOSIGNAL);
>>>> -     if(result == -1) {
>>>> -             if(errno != EPIPE)
>>>> -                     PERROR("send");
>>>> -             return -1;
>>>> +     sock = malloc(sizeof(struct ustcomm_sock));
>>>> +     if (!sock) {
>>>> +             perror("malloc: couldn't allocate ustcomm_sock");
>>>> +             return NULL;
>>>>       }
>>>> -     else if(result == 0) {
>>>> -             return 0;
>>>> +
>>>> +     ev.events = EPOLLIN;
>>>> +     ev.data.ptr = sock;
>>>> +     sock->fd = fd;
>>>> +
>>>> +     if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock->fd, &ev) == -1) {
>>>> +             perror("epoll_ctl: failed to add socket\n");
>>>> +             free(sock);
>>>> +             return NULL;
>>>>       }
>>>>
>>>> -     DBG("sent message \"%s\"", msg);
>>>> -     return 1;
>>>> +     sock->epoll_fd = epoll_fd;
>>>> +     if (list) {
>>>> +             list_add(&sock->list, list);
>>>> +     } else {
>>>> +             INIT_LIST_HEAD(&sock->list);
>>>> +     }
>>>> +
>>>> +     return sock;
>>>>  }
>>>>
>>>> -/* Called by an app to ask the consumer daemon to connect to it. */
>>>> +void ustcomm_del_sock(struct ustcomm_sock *sock, int keep_in_epoll)
>>>> +{
>>>> +     list_del(&sock->list);
>>>> +     if (!keep_in_epoll) {
>>>> +             if (epoll_ctl(sock->epoll_fd, EPOLL_CTL_DEL, sock->fd,
>>>> NULL) == -1) {
>>>> +                     PERROR("epoll_ctl: failed to delete socket");
>>>> +             }
>>>> +     }
>>>> +     close(sock->fd);
>>>> +     free(sock);
>>>> +}
>>>>
>>>> -int ustcomm_request_consumer(pid_t pid, const char *channel)
>>>> +struct ustcomm_sock * ustcomm_init_named_socket(const char *name,
>>>> +                                             int epoll_fd)
>>>>  {
>>>> -     char path[UNIX_PATH_MAX];
>>>>       int result;
>>>> -     char *msg=NULL;
>>>> -     int retval = 0;
>>>> -     struct ustcomm_connection conn;
>>>> -     char *explicit_daemon_socket_path;
>>>> +     int fd;
>>>> +     size_t sock_addr_size;
>>>> +     struct sockaddr_un * addr;
>>>> +     struct ustcomm_sock *sock;
>>>>
>>>> -     explicit_daemon_socket_path = getenv("UST_DAEMON_SOCKET");
>>>> -     if(explicit_daemon_socket_path) {
>>>> -             /* user specified explicitly a socket path */
>>>> -             result = snprintf(path, UNIX_PATH_MAX, "%s",
>>>> explicit_daemon_socket_path);
>>>> -     }
>>>> -     else {
>>>> -             /* just use the default path */
>>>> -             result = snprintf(path, UNIX_PATH_MAX, "%s/ustd",
>>>> SOCK_DIR);
>>>> +     fd = socket(PF_UNIX, SOCK_STREAM, 0);
>>>> +     if(fd == -1) {
>>>> +             PERROR("socket");
>>>> +             return NULL;
>>>>       }
>>>>
>>>> -     if(result >= UNIX_PATH_MAX) {
>>>> -             ERR("string overflow allocating socket name");
>>>> -             return -1;
>>>> +     addr = create_sock_addr(name, &sock_addr_size);
>>>> +     if (addr == NULL) {
>>>> +             ERR("allocating addr, UST thread bailing");
>>>> +             goto close_sock;
>>>>       }
>>>>
>>>> -     if (asprintf(&msg, "collect %d %s", pid, channel) < 0) {
>>>> -             ERR("ustcomm_request_consumer : asprintf failed
>>>> (collect %d/%s)",
>>>> -                 pid, channel);
>>>> -             return -1;
>>>> +     result = access(name, F_OK);
>>>> +     if(result == 0) {
>>>> +             /* file exists */
>>>> +             result = unlink(name);
>>>> +             if(result == -1) {
>>>> +                     PERROR("unlink of socket file");
>>>> +                     goto free_addr;
>>>> +             }
>>>> +             DBG("socket already exists; overwriting");
>>>>       }
>>>>
>>>> -     /* don't signal it because it's the daemon */
>>>> -     result = ustcomm_connect_path(path, &conn, -1);
>>>> +     result = bind(fd, (struct sockaddr *)addr, sock_addr_size);
>>>>       if(result == -1) {
>>>> -             WARN("ustcomm_connect_path failed");
>>>> -             retval = -1;
>>>> -             goto del_string;
>>>> +             PERROR("bind");
>>>> +             goto free_addr;
>>>>       }
>>>>
>>>> -     result = ustcomm_send_request(&conn, msg, NULL);
>>>> +     result = listen(fd, 1);
>>>>       if(result == -1) {
>>>> -             WARN("ustcomm_send_request failed");
>>>> -             retval = -1;
>>>> -             goto disconnect;
>>>> +             PERROR("listen");
>>>> +             goto free_addr;
>>>>       }
>>>>
>>>> -     disconnect:
>>>> -     ustcomm_disconnect(&conn);
>>>> -     del_string:
>>>> -     free(msg);
>>>> +     sock = ustcomm_init_sock(fd, epoll_fd,
>>>> +                              NULL);
>>>> +     if (!sock) {
>>>> +             ERR("failed to create ustcomm_sock");
>>>> +             goto free_addr;
>>>> +     }
>>>>
>>>> -     return retval;
>>>> -}
>>>> +     free(addr);
>>>>
>>>> -/* returns 1 to indicate a message was received
>>>> - * returns 0 to indicate no message was received (end of stream)
>>>> - * returns -1 to indicate an error
>>>> - */
>>>> +     return sock;
>>>>
>>>> -#define RECV_INCREMENT 1000
>>>> -#define RECV_INITIAL_BUF_SIZE 10
>>>> +free_addr:
>>>> +     free(addr);
>>>> +close_sock:
>>>> +     close(fd);
>>>>
>>>> -static int recv_message_fd(int fd, char **recv_buf, int
>>>> *recv_buf_size, int *recv_buf_alloc, char **msg)
>>>> +     return NULL;
>>>> +}
>>>> +
>>>> +void ustcomm_del_named_sock(struct ustcomm_sock *sock,
>>>> +                         int keep_socket_file)
>>>>  {
>>>> -     int result;
>>>> +     int result, fd;
>>>> +     struct stat st;
>>>> +     struct sockaddr dummy;
>>>> +     struct sockaddr_un *sockaddr = NULL;
>>>> +     int alloc_size;
>>>>
>>>> -     /* 1. Check if there is a message in the buf */
>>>> -     /* 2. If not, do:
>>>> -           2.1 receive chunk and put it in buffer
>>>> -        2.2 process full message if there is one
>>>> -        -- while no message arrived
>>>> -     */
>>>> +     fd = sock->fd;
>>>>
>>>> -     for(;;) {
>>>> -             int i;
>>>> -             int nulfound = 0;
>>>> +     if(!keep_socket_file) {
>>>>
>>>> -             /* Search for full message in buffer */
>>>> -             for(i=0; i<*recv_buf_size; i++) {
>>>> -                     if((*recv_buf)[i] == '\0') {
>>>> -                             nulfound = 1;
>>>> -                             break;
>>>> -                     }
>>>> +             /* Get the socket name */
>>>> +             alloc_size = sizeof(dummy);
>>>> +             if (getsockname(fd, &dummy, (socklen_t *)&alloc_size) <
>>>> 0) {
>>>> +                     PERROR("getsockname failed");
>>>> +                     return;
>>>>               }
>>>>
>>>> -             /* Process found message */
>>>> -             if(nulfound == 1) {
>>>> -                     char *newbuf;
>>>> -
>>>> -                     if(i == 0) {
>>>> -                             /* problem */
>>>> -                             WARN("received empty message");
>>>> -                     }
>>>> -                     *msg = strndup(*recv_buf, i);
>>>> -
>>>> -                     /* Remove processed message from buffer */
>>>> -                     newbuf = (char *) malloc(*recv_buf_size - (i+1));
>>>> -                     memcpy(newbuf, *recv_buf + (i+1),
>>>> *recv_buf_size - (i+1));
>>>> -                     free(*recv_buf);
>>>> -                     *recv_buf = newbuf;
>>>> -                     *recv_buf_size -= (i+1);
>>>> -                     *recv_buf_alloc -= (i+1);
>>>> -
>>>> -                     return 1;
>>>> +             sockaddr = malloc(alloc_size);
>>>> +             if (!sockaddr) {
>>>> +                     ERR("failed to allocate sockaddr");
>>>> +                     return;
>>>>               }
>>>>
>>>> -             /* Receive a chunk from the fd */
>>>> -             if(*recv_buf_alloc - *recv_buf_size < RECV_INCREMENT) {
>>>> -                     *recv_buf_alloc += RECV_INCREMENT -
>>>> (*recv_buf_alloc - *recv_buf_size);
>>>> -                     *recv_buf = (char *) realloc(*recv_buf,
>>>> *recv_buf_alloc);
>>>> +             if (getsockname(fd, sockaddr, (socklen_t *)&alloc_size)
>>>> < 0) {
>>>> +                     PERROR("getsockname failed");
>>>> +                     goto free_sockaddr;
>>>>               }
>>>>
>>>> -             result = recv(fd, *recv_buf+*recv_buf_size,
>>>> RECV_INCREMENT, 0);
>>>> +             /* Destroy socket */
>>>> +             result = stat(sockaddr->sun_path, &st);
>>>>               if(result == -1) {
>>>> -                     if(errno == ECONNRESET) {
>>>> -                             *recv_buf_size = 0;
>>>> -                             return 0;
>>>> -                     }
>>>> -                     else if(errno == EINTR) {
>>>> -                             return -1;
>>>> -                     }
>>>> -                     else {
>>>> -                             PERROR("recv");
>>>> -                             return -1;
>>>> -                     }
>>>> +                     PERROR("stat (%s)", sockaddr->sun_path);
>>>> +                     goto free_sockaddr;
>>>>               }
>>>> -             if(result == 0) {
>>>> -                     return 0;
>>>> +
>>>> +             /* Paranoid check before deleting. */
>>>> +             result = S_ISSOCK(st.st_mode);
>>>> +             if(!result) {
>>>> +                     ERR("The socket we are about to delete is not a
>>>> socket.");
>>>> +                     goto free_sockaddr;
>>>>               }
>>>> -             *recv_buf_size += result;
>>>>
>>>> -             /* Go back to the beginning to check if there is a full
>>>> message in the buffer */
>>>> +             result = unlink(sockaddr->sun_path);
>>>> +             if(result == -1) {
>>>> +                     PERROR("unlink");
>>>> +             }
>>>>       }
>>>>
>>>> -     DBG("received message \"%s\"", *recv_buf);
>>>> +     ustcomm_del_sock(sock, keep_socket_file);
>>>>
>>>> -     return 1;
>>>> +free_sockaddr:
>>>> +     free(sockaddr);
>>>>
>>>>  }
>>>>
>>>> -static int recv_message_conn(struct ustcomm_connection *conn, char
>>>> **msg)
>>>> -{
>>>> -     return recv_message_fd(conn->fd, &conn->recv_buf,
>>>> &conn->recv_buf_size, &conn->recv_buf_alloc, msg);
>>>> -}
>>>>
>>>> -int ustcomm_send_reply(struct ustcomm_server *server, char *msg,
>>>> struct ustcomm_source *src)
>>>> +/* Called by an app to ask the consumer daemon to connect to it. */
>>>> +
>>>> +int ustcomm_request_consumer(pid_t pid, const char *channel)
>>>>  {
>>>> -     int result;
>>>> +     int result, daemon_fd;
>>>> +     int retval = 0;
>>>> +     char *msg=NULL;
>>>> +     char *explicit_daemon_socket_path, *daemon_path;
>>>>
>>>> -     result = send_message_fd(src->fd, msg);
>>>> -     if(result < 0) {
>>>> -             ERR("error in send_message_fd");
>>>> +     explicit_daemon_socket_path = getenv("UST_DAEMON_SOCKET");
>>>> +     if (explicit_daemon_socket_path) {
>>>> +             /* user specified explicitly a socket path */
>>>> +             result = asprintf(&daemon_path, "%s",
>>>> explicit_daemon_socket_path);
>>>> +     } else {
>>>> +             /* just use the default path */
>>>> +             result = asprintf(&daemon_path, "%s/ustd", SOCK_DIR);
>>>> +     }
>>>> +     if (result == -1) {
>>>> +             ERR("string overflow allocating socket name");
>>>>               return -1;
>>>>       }
>>>>
>>>> -     return 0;
>>>> -}
>>>> -
>>>> -/* Called after a fork. */
>>>> +     if (asprintf(&msg, "collect %d %s", pid, channel) < 0) {
>>>> +             ERR("ustcomm_request_consumer : asprintf failed
>>>> (collect %d/%s)",
>>>> +                 pid, channel);
>>>> +             retval = -1;
>>>> +             goto free_daemon_path;
>>>> +     }
>>>>
>>>> -int ustcomm_close_all_connections(struct ustcomm_server *server)
>>>> -{
>>>> -     struct ustcomm_connection *conn;
>>>> -     struct ustcomm_connection *deletable_conn = NULL;
>>>> +     result = ustcomm_connect_path(daemon_path, &daemon_fd);
>>>> +     if (result == -1) {
>>>> +             WARN("ustcomm_connect_path failed, daemon_path: %s",
>>>> +                  daemon_path);
>>>> +             retval = -1;
>>>> +             goto del_string;
>>>> +     }
>>>>
>>>> -     list_for_each_entry(conn, &server->connections, list) {
>>>> -             free(deletable_conn);
>>>> -             deletable_conn = conn;
>>>> -             ustcomm_close_app(conn);
>>>> -             list_del(&conn->list);
>>>> +     result = ustcomm_send_request(daemon_fd, msg, NULL);
>>>> +     if (result == -1) {
>>>> +             WARN("ustcomm_send_request failed, daemon path: %s",
>>>> +                  daemon_path);
>>>> +             retval = -1;
>>>>       }
>>>>
>>>> -     return 0;
>>>> +     close(daemon_fd);
>>>> +del_string:
>>>> +     free(msg);
>>>> +free_daemon_path:
>>>> +     free(daemon_path);
>>>> +
>>>> +     return retval;
>>>>  }
>>>>
>>>> -/* @timeout: max blocking time in milliseconds, -1 means infinity
>>>> - *
>>>> - * returns 1 to indicate a message was received
>>>> - * returns 0 to indicate no message was received
>>>> +/* returns 1 to indicate a message was received
>>>> + * returns 0 to indicate no message was received (end of stream)
>>>>   * returns -1 to indicate an error
>>>>   */
>>>> -
>>>> -int ustcomm_recv_message(struct ustcomm_server *server, char **msg,
>>>> struct ustcomm_source *src, int timeout)
>>>> +int ustcomm_recv_fd(int sock,
>>>> +                 struct ustcomm_header *header,
>>>> +                 char **data, int *fd)
>>>>  {
>>>> -     struct pollfd *fds;
>>>> -     struct ustcomm_connection **conn_table;
>>>> -     struct ustcomm_connection *conn;
>>>>       int result;
>>>>       int retval;
>>>> -
>>>> -     for(;;) {
>>>> -             int idx = 0;
>>>> -             int n_fds = 1;
>>>> -
>>>> -             list_for_each_entry(conn, &server->connections, list) {
>>>> -                     n_fds++;
>>>> -             }
>>>> -
>>>> -             fds = (struct pollfd *) zmalloc(n_fds * sizeof(struct
>>>> pollfd));
>>>> -             if(fds == NULL) {
>>>> -                     ERR("zmalloc returned NULL");
>>>> +     struct ustcomm_header peek_header;
>>>> +     struct iovec iov[2];
>>>> +     struct msghdr msg;
>>>> +     struct cmsghdr *cmsg;
>>>> +     char buf[CMSG_SPACE(sizeof(int))];
>>>> +
>>>> +     result = recv(sock, &peek_header, sizeof(peek_header),
>>>> +                   MSG_PEEK | MSG_WAITALL);
>>>> +     if (result <= 0) {
>>>> +             if(errno == ECONNRESET) {
>>>> +                     return 0;
>>>> +             } else if (errno == EINTR) {
>>>> +                     return -1;
>>>> +             } else if (result < 0) {
>>>> +                     PERROR("recv");
>>>>                       return -1;
>>>>               }
>>>> +             return 0;
>>>> +     }
>>>>
>>>> -             conn_table = (struct ustcomm_connection **)
>>>> zmalloc(n_fds * sizeof(struct ustcomm_connection *));
>>>> -             if(conn_table == NULL) {
>>>> -                     ERR("zmalloc returned NULL");
>>>> -                     retval = -1;
>>>> -                     goto free_fds_return;
>>>> -             }
>>>> +     memset(&msg, 0, sizeof(msg));
>>>>
>>>> -             /* special idx 0 is for listening socket */
>>>> -             fds[idx].fd = server->listen_fd;
>>>> -             fds[idx].events = POLLIN;
>>>> -             idx++;
>>>> +     iov[0].iov_base = (char *)header;
>>>> +     iov[0].iov_len = sizeof(struct ustcomm_header);
>>>>
>>>> -             list_for_each_entry(conn, &server->connections, list) {
>>>> -                     fds[idx].fd = conn->fd;
>>>> -                     fds[idx].events = POLLIN;
>>>> -                     conn_table[idx] = conn;
>>>> -                     idx++;
>>>> -             }
>>>> +     msg.msg_iov = iov;
>>>> +     msg.msg_iovlen = 1;
>>>>
>>>> -             result = poll(fds, n_fds, timeout);
>>>> -             if(result == -1 && errno == EINTR) {
>>>> -                     /* That's ok. ustd receives signals to notify
>>>> it must shutdown. */
>>>> -                     retval = -1;
>>>> -                     goto free_conn_table_return;
>>>> -             }
>>>> -             else if(result == -1) {
>>>> -                     PERROR("poll");
>>>> -                     retval = -1;
>>>> -                     goto free_conn_table_return;
>>>> +     if (peek_header.size) {
>>>> +             if (peek_header.size < 0 || peek_header.size > 100) {
>>>> +                     WARN("big peek header! %d", peek_header.size);
>>>>               }
>>>> -             else if(result == 0) {
>>>> -                     retval = 0;
>>>> -                     goto free_conn_table_return;
>>>> +             *data = malloc(peek_header.size);
>>>> +             if (!*data) {
>>>> +                     ERR("failed to allocate space for message");
>>>>               }
>>>>
>>>> -             if(fds[0].revents) {
>>>> -                     struct ustcomm_connection *newconn;
>>>> -                     int newfd;
>>>> +             iov[1].iov_base = (char *)*data;
>>>> +             iov[1].iov_len = peek_header.size;
>>>>
>>>> -                     result = newfd = accept(server->listen_fd,
>>>> NULL, NULL);
>>>> -                     if(result == -1) {
>>>> -                             PERROR("accept");
>>>> -                             retval = -1;
>>>> -                             goto free_conn_table_return;
>>>> -                     }
>>>> +             msg.msg_iovlen++;
>>>> +     }
>>>>
>>>> -                     newconn = (struct ustcomm_connection *)
>>>> zmalloc(sizeof(struct ustcomm_connection));
>>>> -                     if(newconn == NULL) {
>>>> -                             ERR("zmalloc returned NULL");
>>>> -                             return -1;
>>>> -                     }
>>>> +     if (fd && peek_header.fd_included) {
>>>> +             msg.msg_control = buf;
>>>> +             msg.msg_controllen = sizeof(buf);
>>>> +     }
>>>>
>>>> -                     ustcomm_init_connection(newconn);
>>>> -                     newconn->fd = newfd;
>>>> +     result = recvmsg(sock, &msg,
>>>> +                      MSG_WAITALL);
>>>>
>>>> -                     list_add(&newconn->list, &server->connections);
>>>> +     if (result <= 0) {
>>>> +             if(errno == ECONNRESET) {
>>>> +                     retval = 0;
>>>> +             } else if (errno == EINTR) {
>>>> +                     retval = -1;
>>>> +             } else if (result < 0) {
>>>> +                     PERROR("recv");
>>>> +                     retval = -1;
>>>> +             } else {
>>>> +                     retval = 0;
>>>>               }
>>>> -
>>>> -             for(idx=1; idx<n_fds; idx++) {
>>>> -                     if(fds[idx].revents) {
>>>> -                             retval =
>>>> recv_message_conn(conn_table[idx], msg);
>>>> -                             if(src)
>>>> -                                     src->fd = fds[idx].fd;
>>>> -
>>>> -                             if(retval == 0) {
>>>> -                                     /* connection finished */
>>>> -                                     list_for_each_entry(conn,
>>>> &server->connections, list) {
>>>> -                                             if(conn->fd ==
>>>> fds[idx].fd) {
>>>> -                                                    
>>>> ustcomm_close_app(conn);
>>>> -                                                    
>>>> list_del(&conn->list);
>>>> -                                                     free(conn);
>>>> -                                                     break;
>>>> -                                             }
>>>> -                                     }
>>>> -                             }
>>>> -                             else {
>>>> -                                     goto free_conn_table_return;
>>>> -                             }
>>>> +             free(*data);
>>>> +             return retval;
>>>> +     }
>>>> +
>>>> +     if (fd && peek_header.fd_included) {
>>>> +             cmsg = CMSG_FIRSTHDR(&msg);
>>>> +             result = 0;
>>>> +             while (cmsg != NULL) {
>>>> +                     if (cmsg->cmsg_level == SOL_SOCKET
>>>> +                         && cmsg->cmsg_type  == SCM_RIGHTS) {
>>>> +                             *fd = *(int *) CMSG_DATA(cmsg);
>>>> +                             result = 1;
>>>> +                             break;
>>>>                       }
>>>> +                     cmsg = CMSG_NXTHDR(&msg, cmsg);
>>>> +             }
>>>> +             if (!result) {
>>>> +                     ERR("Failed to receive file descriptor\n");
>>>>               }
>>>> -
>>>> -             free(fds);
>>>> -             free(conn_table);
>>>>       }
>>>>
>>>> -free_conn_table_return:
>>>> -     free(conn_table);
>>>> -free_fds_return:
>>>> -     free(fds);
>>>> -     return retval;
>>>> +     return 1;
>>>>  }
>>>>
>>>> -int ustcomm_ustd_recv_message(struct ustcomm_ustd *ustd, char **msg,
>>>> struct ustcomm_source *src, int timeout)
>>>> +int ustcomm_recv(int sock,
>>>> +              struct ustcomm_header *header,
>>>> +              char **data)
>>>>  {
>>>> -     return ustcomm_recv_message(&ustd->server, msg, src, timeout);
>>>> +     return ustcomm_recv_fd(sock, header, data, NULL);
>>>>  }
>>>>
>>>> -int ustcomm_app_recv_message(struct ustcomm_app *app, char **msg,
>>>> struct ustcomm_source *src, int timeout)
>>>> +
>>>> +int recv_message_conn(int sock, char **msg)
>>>>  {
>>>> -     return ustcomm_recv_message(&app->server, msg, src, timeout);
>>>> -}
>>>> +     struct ustcomm_header header;
>>>>
>>>> -/* This removes src from the list of active connections of app.
>>>> - */
>>>> +     return ustcomm_recv(sock, &header, msg);
>>>> +}
>>>>
>>>> -int ustcomm_app_detach_client(struct ustcomm_app *app, struct
>>>> ustcomm_source *src)
>>>> +int ustcomm_send_fd(int sock,
>>>> +                 const struct ustcomm_header *header,
>>>> +                 const char *data,
>>>> +                 int *fd)
>>>>  {
>>>> -     struct ustcomm_server *server = (struct ustcomm_server *)app;
>>>> -     struct ustcomm_connection *conn;
>>>> +     struct iovec iov[2];
>>>> +     struct msghdr msg;
>>>> +     int result;
>>>> +     struct cmsghdr *cmsg;
>>>> +     char buf[CMSG_SPACE(sizeof(int))];
>>>> +
>>>> +     memset(&msg, 0, sizeof(msg));
>>>> +
>>>> +     iov[0].iov_base = (char *)header;
>>>> +     iov[0].iov_len = sizeof(struct ustcomm_header);
>>>> +
>>>> +     msg.msg_iov = iov;
>>>> +     msg.msg_iovlen = 1;
>>>> +
>>>> +     if (header->size) {
>>>> +             iov[1].iov_base = (char *)data;
>>>> +             iov[1].iov_len = header->size;
>>>> +
>>>> +             msg.msg_iovlen++;
>>>>
>>>> -     list_for_each_entry(conn, &server->connections, list) {
>>>> -             if(conn->fd == src->fd) {
>>>> -                     list_del(&conn->list);
>>>> -                     goto found;
>>>> -             }
>>>>       }
>>>>
>>>> -     return -1;
>>>> -found:
>>>> -     return src->fd;
>>>> +     if (fd && header->fd_included) {
>>>> +             msg.msg_control = buf;
>>>> +             msg.msg_controllen = sizeof(buf);
>>>> +             cmsg = CMSG_FIRSTHDR(&msg);
>>>> +             cmsg->cmsg_level = SOL_SOCKET;
>>>> +             cmsg->cmsg_type = SCM_RIGHTS;
>>>> +             cmsg->cmsg_len = CMSG_LEN(sizeof(int));
>>>> +             *(int *) CMSG_DATA(cmsg) = *fd;
>>>> +             msg.msg_controllen = cmsg->cmsg_len;
>>>> +     }
>>>> +
>>>> +     result = sendmsg(sock, &msg, MSG_NOSIGNAL);
>>>> +     if (result < 0 && errno != EPIPE) {
>>>> +             PERROR("sendmsg failed");
>>>> +     }
>>>> +     return result;
>>>>  }
>>>>
>>>> -static int init_named_socket(const char *name, char **path_out)
>>>> +int ustcomm_send(int sock,
>>>> +              const struct ustcomm_header *header,
>>>> +              const char *data)
>>>>  {
>>>> -     int result;
>>>> -     int fd;
>>>> +     return ustcomm_send_fd(sock, header, data, NULL);
>>>> +}
>>>>
>>>> -     struct sockaddr_un addr;
>>>> -
>>>> -     result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
>>>> -     if(result == -1) {
>>>> -             PERROR("socket");
>>>> -             return -1;
>>>> -     }
>>>> +int ustcomm_send_reply(char *msg, int sock)
>>>> +{
>>>> +     int result;
>>>> +     struct ustcomm_header header;
>>>>
>>>> -     addr.sun_family = AF_UNIX;
>>>> +     memset(&header, 0, sizeof(header));
>>>>
>>>> -     strncpy(addr.sun_path, name, UNIX_PATH_MAX);
>>>> -     addr.sun_path[UNIX_PATH_MAX-1] = '\0';
>>>> +     header.size = strlen(msg) + 1;
>>>>
>>>> -     result = access(name, F_OK);
>>>> -     if(result == 0) {
>>>> -             /* file exists */
>>>> -             result = unlink(name);
>>>> -             if(result == -1) {
>>>> -                     PERROR("unlink of socket file");
>>>> -                     goto close_sock;
>>>> -             }
>>>> -             DBG("socket already exists; overwriting");
>>>> +     result = ustcomm_send(sock, &header, msg);
>>>> +     if(result < 0) {
>>>> +             ERR("error in ustcomm_send");
>>>> +             return result;
>>>>       }
>>>>
>>>> -     result = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
>>>> -     if(result == -1) {
>>>> -             PERROR("bind");
>>>> -             goto close_sock;
>>>> -     }
>>>> +     return 0;
>>>> +}
>>>>
>>>> -     result = listen(fd, 1);
>>>> -     if(result == -1) {
>>>> -             PERROR("listen");
>>>> -             goto close_sock;
>>>> -     }
>>>> +int ustcomm_send_req(int sock,
>>>> +                  const struct ustcomm_header *req_header,
>>>> +                  const char *data,
>>>> +                  char **response)
>>>> +{
>>>> +     int result;
>>>> +     struct ustcomm_header res_header;
>>>>
>>>> -     if(path_out) {
>>>> -             *path_out = strdup(addr.sun_path);
>>>> +     result = ustcomm_send(sock, req_header, data);
>>>> +     if ( result <= 0) {
>>>> +             return result;
>>>>       }
>>>>
>>>> -     return fd;
>>>> +     if (!response) {
>>>> +             return 1;
>>>> +     }
>>>>
>>>> -     close_sock:
>>>> -     close(fd);
>>>> +     return ustcomm_recv(sock,
>>>> +                         &res_header,
>>>> +                         response);
>>>>
>>>> -     return -1;
>>>>  }
>>>>
>>>>  /*
>>>> @@ -527,27 +545,17 @@ static int init_named_socket(const char *name,
>>>> char **path_out)
>>>>   * ECONNRESET, which is normal when the application dies.
>>>>   */
>>>>
>>>> -int ustcomm_send_request(struct ustcomm_connection *conn, const char
>>>> *req, char **reply)
>>>> +int ustcomm_send_request(int sock, const char *req, char **reply)
>>>>  {
>>>> -     int result;
>>>> +     struct ustcomm_header req_header;
>>>>
>>>> -     /* Send including the final \0 */
>>>> -     result = send_message_fd(conn->fd, req);
>>>> -     if(result != 1)
>>>> -             return result;
>>>> +     req_header.size = strlen(req) + 1;
>>>>
>>>> -     if(!reply)
>>>> -             return 1;
>>>> +     return ustcomm_send_req(sock,
>>>> +                             &req_header,
>>>> +                             req,
>>>> +                             reply);
>>>>
>>>> -     result = recv_message_conn(conn, reply);
>>>> -     if(result == -1) {
>>>> -             return -1;
>>>> -     }
>>>> -     else if(result == 0) {
>>>> -             return 0;
>>>> -     }
>>>> -
>>>> -     return 1;
>>>>  }
>>>>
>>>>  /* Return value:
>>>> @@ -555,52 +563,45 @@ int ustcomm_send_request(struct
>>>> ustcomm_connection *conn, const char *req, char
>>>>   * -1: error
>>>>   */
>>>>
>>>> -int ustcomm_connect_path(const char *path, struct ustcomm_connection
>>>> *conn, pid_t signalpid)
>>>> +int ustcomm_connect_path(const char *name, int *connection_fd)
>>>>  {
>>>> -     int fd;
>>>> -     int result;
>>>> -     struct sockaddr_un addr;
>>>> +     int result, fd;
>>>> +     size_t sock_addr_size;
>>>> +     struct sockaddr_un *addr;
>>>>
>>>> -     ustcomm_init_connection(conn);
>>>> -
>>>> -     result = fd = socket(PF_UNIX, SOCK_STREAM, 0);
>>>> -     if(result == -1) {
>>>> +     fd = socket(PF_UNIX, SOCK_STREAM, 0);
>>>> +     if(fd == -1) {
>>>>               PERROR("socket");
>>>>               return -1;
>>>>       }
>>>>
>>>> -     addr.sun_family = AF_UNIX;
>>>> -
>>>> -     result = snprintf(addr.sun_path, UNIX_PATH_MAX, "%s", path);
>>>> -     if(result >= UNIX_PATH_MAX) {
>>>> -             ERR("string overflow allocating socket name");
>>>> -             return -1;
>>>> -     }
>>>> -
>>>> -     if(signalpid >= 0) {
>>>> -             result = signal_process(signalpid);
>>>> -             if(result == -1) {
>>>> -                     ERR("could not signal process");
>>>> -                     return -1;
>>>> -             }
>>>> +     addr = create_sock_addr(name, &sock_addr_size);
>>>> +     if (addr == NULL) {
>>>> +             ERR("allocating addr failed");
>>>> +             goto close_sock;
>>>>       }
>>>>
>>>> -     result = connect(fd, (struct sockaddr *)&addr, sizeof(addr));
>>>> +     result = connect(fd, (struct sockaddr *)addr, sock_addr_size);
>>>>       if(result == -1) {
>>>> -             PERROR("connect (path=%s)", path);
>>>> -             return -1;
>>>> +             PERROR("connect (path=%s)", name);
>>>> +             goto free_sock_addr;
>>>>       }
>>>>
>>>> -     conn->fd = fd;
>>>> +     *connection_fd = fd;
>>>> +
>>>> +     free(addr);
>>>>
>>>>       return 0;
>>>> -}
>>>>
>>>> -int ustcomm_disconnect(struct ustcomm_connection *conn)
>>>> -{
>>>> -     return close(conn->fd);
>>>> +free_sock_addr:
>>>> +     free(addr);
>>>> +close_sock:
>>>> +     close(fd);
>>>> +
>>>> +     return -1;
>>>>  }
>>>>
>>>> +
>>>>  /* Open a connection to a traceable app.
>>>>   *
>>>>   * Return value:
>>>> @@ -608,35 +609,30 @@ int ustcomm_disconnect(struct
>>>> ustcomm_connection *conn)
>>>>   * -1: error
>>>>   */
>>>>
>>>> -int ustcomm_connect_app(pid_t pid, struct ustcomm_connection *conn)
>>>> +int ustcomm_connect_app(pid_t pid, int *app_fd)
>>>>  {
>>>>       int result;
>>>> -     char path[UNIX_PATH_MAX];
>>>> -
>>>> +     int retval = 0;
>>>> +     char *name;
>>>>
>>>> -     result = snprintf(path, UNIX_PATH_MAX, "%s/%d", SOCK_DIR, pid);
>>>> -     if(result >= UNIX_PATH_MAX) {
>>>> -             ERR("string overflow allocating socket name");
>>>> +     result = asprintf(&name, "%s/%d", SOCK_DIR, pid);
>>>> +     if (result < 0) {
>>>> +             ERR("failed to allocate socket name");
>>>>               return -1;
>>>>       }
>>>>
>>>> -     return ustcomm_connect_path(path, conn, pid);
>>>> -}
>>>> -
>>>> -/* Close a connection to a traceable app. It frees the
>>>> - * resources. It however does not free the
>>>> - * ustcomm_connection itself.
>>>> - */
>>>> +     result = ustcomm_connect_path(name, app_fd);
>>>> +     if (result < 0) {
>>>> +             ERR("failed to connect to app");
>>>> +             retval = -1;
>>>> +     }
>>>>
>>>> -int ustcomm_close_app(struct ustcomm_connection *conn)
>>>> -{
>>>> -     close(conn->fd);
>>>> -     free(conn->recv_buf);
>>>> +     free(name);
>>>>
>>>> -     return 0;
>>>> +     return retval;
>>>>  }
>>>>
>>>> -static int ensure_dir_exists(const char *dir)
>>>> +int ensure_dir_exists(const char *dir)
>>>>  {
>>>>       struct stat st;
>>>>       int result;
>>>> @@ -663,139 +659,10 @@ static int ensure_dir_exists(const char *dir)
>>>>       return 0;
>>>>  }
>>>>
>>>> -/* Called by an application to initialize its server so daemons can
>>>> - * connect to it.
>>>> - */
>>>> -
>>>> -int ustcomm_init_app(pid_t pid, struct ustcomm_app *handle)
>>>> -{
>>>> -     int result;
>>>> -     char *name;
>>>> -
>>>> -     result = asprintf(&name, "%s/%d", SOCK_DIR, (int)pid);
>>>> -     if(result >= UNIX_PATH_MAX) {
>>>> -             ERR("string overflow allocating socket name");
>>>> -             return -1;
>>>> -     }
>>>> -
>>>> -     result = ensure_dir_exists(SOCK_DIR);
>>>> -     if(result == -1) {
>>>> -             ERR("Unable to create socket directory %s", SOCK_DIR);
>>>> -             return -1;
>>>> -     }
>>>> -
>>>> -     handle->server.listen_fd = init_named_socket(name,
>>>> &(handle->server.socketpath));
>>>> -     if(handle->server.listen_fd < 0) {
>>>> -             ERR("Error initializing named socket (%s). Check that
>>>> directory exists and that it is writable.", name);
>>>> -             goto free_name;
>>>> -     }
>>>> -     free(name);
>>>> -
>>>> -     INIT_LIST_HEAD(&handle->server.connections);
>>>> -
>>>> -     return 0;
>>>> -
>>>> -free_name:
>>>> -     free(name);
>>>> -     return -1;
>>>> -}
>>>> -
>>>>  /* Used by the daemon to initialize its server so applications
>>>>   * can connect to it.
>>>>   */
>>>>
>>>> -int ustcomm_init_ustd(struct ustcomm_ustd *handle, const char
>>>> *sock_path)
>>>> -{
>>>> -     char *name;
>>>> -     int retval = 0;
>>>> -
>>>> -     if(sock_path) {
>>>> -             if (asprintf(&name, "%s", sock_path) < 0) {
>>>> -                     ERR("ustcomm_init_ustd : asprintf failed
>>>> (sock_path %s)",
>>>> -                         sock_path);
>>>> -                     return -1;
>>>> -             }
>>>> -     }
>>>> -     else {
>>>> -             int result;
>>>> -
>>>> -             /* Only check if socket dir exists if we are using the
>>>> default directory */
>>>> -             result = ensure_dir_exists(SOCK_DIR);
>>>> -             if(result == -1) {
>>>> -                     ERR("Unable to create socket directory %s",
>>>> SOCK_DIR);
>>>> -                     return -1;
>>>> -             }
>>>> -
>>>> -             if (asprintf(&name, "%s/%s", SOCK_DIR, "ustd") < 0) {
>>>> -                     ERR("ustcomm_init_ustd : asprintf failed
>>>> (%s/ustd)",
>>>> -                         SOCK_DIR);
>>>> -                     return -1;
>>>> -             }
>>>> -     }
>>>> -
>>>> -     handle->server.listen_fd = init_named_socket(name,
>>>> &handle->server.socketpath);
>>>> -     if(handle->server.listen_fd < 0) {
>>>> -             ERR("error initializing named socket at %s", name);
>>>> -             retval = -1;
>>>> -             goto free_name;
>>>> -     }
>>>> -
>>>> -     INIT_LIST_HEAD(&handle->server.connections);
>>>> -
>>>> -free_name:
>>>> -     free(name);
>>>> -
>>>> -     return retval;
>>>> -}
>>>> -
>>>> -static void ustcomm_fini_server(struct ustcomm_server *server, int
>>>> keep_socket_file)
>>>> -{
>>>> -     int result;
>>>> -     struct stat st;
>>>> -
>>>> -     if(!keep_socket_file) {
>>>> -             /* Destroy socket */
>>>> -             result = stat(server->socketpath, &st);
>>>> -             if(result == -1) {
>>>> -                     PERROR("stat (%s)", server->socketpath);
>>>> -                     return;
>>>> -             }
>>>> -
>>>> -             /* Paranoid check before deleting. */
>>>> -             result = S_ISSOCK(st.st_mode);
>>>> -             if(!result) {
>>>> -                     ERR("The socket we are about to delete is not a
>>>> socket.");
>>>> -                     return;
>>>> -             }
>>>> -
>>>> -             result = unlink(server->socketpath);
>>>> -             if(result == -1) {
>>>> -                     PERROR("unlink");
>>>> -             }
>>>> -     }
>>>> -
>>>> -     free(server->socketpath);
>>>> -
>>>> -     result = close(server->listen_fd);
>>>> -     if(result == -1) {
>>>> -             PERROR("close");
>>>> -             return;
>>>> -     }
>>>> -}
>>>> -
>>>> -/* Free a traceable application server */
>>>> -
>>>> -void ustcomm_fini_app(struct ustcomm_app *handle, int keep_socket_file)
>>>> -{
>>>> -     ustcomm_fini_server(&handle->server, keep_socket_file);
>>>> -}
>>>> -
>>>> -/* Free a ustd server */
>>>> -
>>>> -void ustcomm_fini_ustd(struct ustcomm_ustd *handle)
>>>> -{
>>>> -     ustcomm_fini_server(&handle->server, 0);
>>>> -}
>>>>
>>>>  static const char *find_tok(const char *str)
>>>>  {
>>>> @@ -884,89 +751,3 @@ char *nth_token(const char *str, int tok_no)
>>>>
>>>>       return retval;
>>>>  }
>>>> -
>>>> -/* Callback from multipoll.
>>>> - * Receive a new connection on the listening socket.
>>>> - */
>>>> -
>>>> -static int process_mp_incoming_conn(void *priv, int fd, short events)
>>>> -{
>>>> -     struct ustcomm_connection *newconn;
>>>> -     struct ustcomm_server *server = (struct ustcomm_server *) priv;
>>>> -     int newfd;
>>>> -     int result;
>>>> -
>>>> -     result = newfd = accept(server->listen_fd, NULL, NULL);
>>>> -     if(result == -1) {
>>>> -             PERROR("accept");
>>>> -             return -1;
>>>> -     }
>>>> -
>>>> -     newconn = (struct ustcomm_connection *) zmalloc(sizeof(struct
>>>> ustcomm_connection));
>>>> -     if(newconn == NULL) {
>>>> -             ERR("zmalloc returned NULL");
>>>> -             return -1;
>>>> -     }
>>>> -
>>>> -     ustcomm_init_connection(newconn);
>>>> -     newconn->fd = newfd;
>>>> -
>>>> -     list_add(&newconn->list, &server->connections);
>>>> -
>>>> -     return 0;
>>>> -}
>>>> -
>>>> -/* Callback from multipoll.
>>>> - * Receive a message on an existing connection.
>>>> - */
>>>> -
>>>> -static int process_mp_conn_msg(void *priv, int fd, short revents)
>>>> -{
>>>> -     struct ustcomm_multipoll_conn_info *mpinfo = (struct
>>>> ustcomm_multipoll_conn_info *) priv;
>>>> -     int result;
>>>> -     char *msg;
>>>> -     struct ustcomm_source src;
>>>> -
>>>> -     if(revents) {
>>>> -             src.fd = fd;
>>>> -
>>>> -             result = recv_message_conn(mpinfo->conn, &msg);
>>>> -             if(result == -1) {
>>>> -                     ERR("error in recv_message_conn");
>>>> -             }
>>>> -
>>>> -             else if(result == 0) {
>>>> -                     /* connection finished */
>>>> -                     ustcomm_close_app(mpinfo->conn);
>>>> -                     list_del(&mpinfo->conn->list);
>>>> -                     free(mpinfo->conn);
>>>> -             }
>>>> -             else {
>>>> -                     mpinfo->cb(msg, &src);
>>>> -                     free(msg);
>>>> -             }
>>>> -     }
>>>> -
>>>> -     return 0;
>>>> -}
>>>> -
>>>> -int free_ustcomm_client_poll(void *data)
>>>> -{
>>>> -     free(data);
>>>> -     return 0;
>>>> -}
>>>> -
>>>> -void ustcomm_mp_add_app_clients(struct mpentries *ent, struct
>>>> ustcomm_app *app, int (*cb)(char *recvbuf, struct ustcomm_source *src))
>>>> -{
>>>> -     struct ustcomm_connection *conn;
>>>> -
>>>> -     /* add listener socket */
>>>> -     multipoll_add(ent, app->server.listen_fd, POLLIN,
>>>> process_mp_incoming_conn, &app->server, NULL);
>>>> -
>>>> -     list_for_each_entry(conn, &app->server.connections, list) {
>>>> -             struct ustcomm_multipoll_conn_info *mpinfo = (struct
>>>> ustcomm_multipoll_conn_info *) zmalloc(sizeof(struct
>>>> ustcomm_multipoll_conn_info));
>>>> -             mpinfo->conn = conn;
>>>> -             mpinfo->cb = cb;
>>>> -             multipoll_add(ent, conn->fd, POLLIN,
>>>> process_mp_conn_msg, mpinfo, free_ustcomm_client_poll);
>>>> -     }
>>>> -}
>>>> diff --git a/libustcomm/ustcomm.h b/libustcomm/ustcomm.h
>>>> index f96ca16..f3c07b6 100644
>>>> --- a/libustcomm/ustcomm.h
>>>> +++ b/libustcomm/ustcomm.h
>>>> @@ -23,73 +23,62 @@
>>>>  #include <urcu/list.h>
>>>>
>>>>  #include <ust/kcompat/kcompat.h>
>>>> -#include "multipoll.h"
>>>>
>>>>  #define SOCK_DIR "/tmp/ust-app-socks"
>>>>  #define UST_SIGNAL SIGIO
>>>>
>>>> -struct ustcomm_connection {
>>>> +struct ustcomm_sock {
>>>>       struct list_head list;
>>>>       int fd;
>>>> -     /* Data that has not yet been consumed: */
>>>> -     char *recv_buf;
>>>> -     int recv_buf_size;
>>>> -     int recv_buf_alloc;
>>>> +     int epoll_fd;
>>>>  };
>>>>
>>>> -/* ustcomm_server must be shallow-copyable */
>>>> -struct ustcomm_server {
>>>> -     /* the "server" socket for serving the external requests */
>>>> -     int listen_fd;
>>>> -     char *socketpath;
>>>> -
>>>> -     struct list_head connections;
>>>> -};
>>>> -
>>>> -struct ustcomm_ustd {
>>>> -     struct ustcomm_server server;
>>>> +struct ustcomm_header {
>>>> +     int type;
>>>> +     long size;
>>>> +     int command;
>>>> +     int response;
>>>> +     int fd_included;
>>>>  };
>>>>
>>>> -struct ustcomm_app {
>>>> -     struct ustcomm_server server;
>>>> -};
>>>>
>>>> -/* ustcomm_source must be shallow-copyable */
>>>> -struct ustcomm_source {
>>>> -     int fd;
>>>> -     void *priv;
>>>> -};
>>>> +//int send_message_pid(pid_t pid, const char *msg, char **reply);
>>>>
>>>> -struct ustcomm_multipoll_conn_info {
>>>> -     struct ustcomm_connection *conn;
>>>> -     int (*cb)(char *msg, struct ustcomm_source *src);
>>>> -};
>>>> +/* Ensure directory existence, usefull for unix sockets */
>>>> +extern int ensure_dir_exists(const char *dir);
>>>>
>>>> -//int send_message_pid(pid_t pid, const char *msg, char **reply);
>>>> -extern int ustcomm_request_consumer(pid_t pid, const char *channel);
>>>> +/* Create and delete sockets */
>>>> +extern struct ustcomm_sock * ustcomm_init_sock(int fd, int epoll_fd,
>>>> +                                            struct list_head *list);
>>>> +extern void ustcomm_del_sock(struct ustcomm_sock *sock, int
>>>> keep_in_epoll);
>>>>
>>>> -extern int ustcomm_ustd_recv_message(struct ustcomm_ustd *ustd, char
>>>> **msg, struct ustcomm_source *src, int timeout);
>>>> -extern int ustcomm_app_recv_message(struct ustcomm_app *app, char
>>>> **msg, struct ustcomm_source *src, int timeout);
>>>> +/* Create and delete named sockets */
>>>> +extern struct ustcomm_sock * ustcomm_init_named_socket(const char
>>>> *name,
>>>> +                                                    int epoll_fd);
>>>> +extern void ustcomm_del_named_sock(struct ustcomm_sock *sock,
>>>> +                                int keep_socket_file);
>>>>
>>>> -extern int ustcomm_init_app(pid_t pid, struct ustcomm_app *handle);
>>>> -extern void ustcomm_fini_app(struct ustcomm_app *handle, int
>>>> keep_socket_file);
>>>> -extern void ustcomm_fini_ustd(struct ustcomm_ustd *handle);
>>>> +/* Send and receive functions for file descriptors */
>>>> +extern int ustcomm_send_fd(int sock, const struct ustcomm_header
>>>> *header,
>>>> +                        const char *data, int *fd);
>>>> +extern int ustcomm_recv_fd(int sock, struct ustcomm_header *header,
>>>> +                        char **data, int *fd);
>>>>
>>>> -extern int ustcomm_init_ustd(struct ustcomm_ustd *handle, const char
>>>> *sock_path);
>>>> +/* Normal send and receive functions */
>>>> +extern int ustcomm_send(int sock, const struct ustcomm_header *header,
>>>> +                     const char *data);
>>>> +extern int ustcomm_recv(int sock, struct ustcomm_header *header,
>>>> +                     char **data);
>>>>
>>>> -extern int ustcomm_connect_app(pid_t pid, struct ustcomm_connection
>>>> *conn);
>>>> -extern int ustcomm_close_app(struct ustcomm_connection *conn);
>>>> -extern int ustcomm_connect_path(const char *path, struct
>>>> ustcomm_connection *conn, pid_t signalpid);
>>>> -extern int ustcomm_send_request(struct ustcomm_connection *conn,
>>>> const char *req, char **reply);
>>>> -extern int ustcomm_send_reply(struct ustcomm_server *server, char
>>>> *msg, struct ustcomm_source *src);
>>>> -extern int ustcomm_disconnect(struct ustcomm_connection *conn);
>>>> -extern int ustcomm_close_all_connections(struct ustcomm_server
>>>> *server);
>>>> -extern void ustcomm_mp_add_app_clients(struct mpentries *ent, struct
>>>> ustcomm_app *app, int (*cb)(char *recvbuf, struct ustcomm_source *src));
>>>>
>>>> +extern int ustcomm_request_consumer(pid_t pid, const char *channel);
>>>> +extern int ustcomm_connect_app(pid_t pid, int *app_fd);
>>>> +extern int ustcomm_connect_path(const char *path, int *connection_fd);
>>>> +extern int ustcomm_send_request(int sock, const char *req, char
>>>> **reply);
>>>> +extern int ustcomm_send_reply(char *msg, int sock);
>>>> +extern int recv_message_conn(int sock, char **msg);
>>>>  extern int nth_token_is(const char *str, const char *token, int
>>>> tok_no);
>>>>
>>>>  extern char *nth_token(const char *str, int tok_no);
>>>>
>>>> -extern int pid_is_online(pid_t);
>>>> -
>>>>  #endif /* USTCOMM_H */
>>>> diff --git a/libustd/libustd.c b/libustd/libustd.c
>>>> index 999e4da..cb5b123 100644
>>>> --- a/libustd/libustd.c
>>>> +++ b/libustd/libustd.c
>>>> @@ -18,7 +18,10 @@
>>>>
>>>>  #define _GNU_SOURCE
>>>>
>>>> +#include <sys/epoll.h>
>>>>  #include <sys/shm.h>
>>>> +#include <sys/types.h>
>>>> +#include <sys/stat.h>
>>>>  #include <unistd.h>
>>>>  #include <pthread.h>
>>>>  #include <signal.h>
>>>> @@ -64,7 +67,8 @@ int get_subbuffer(struct buffer_info *buf)
>>>>               retval = -1;
>>>>               goto end;
>>>>       }
>>>> -     result = ustcomm_send_request(buf->conn, send_msg, &received_msg);
>>>> +
>>>> +     result = ustcomm_send_request(buf->app_sock, send_msg,
>>>> &received_msg);
>>>>       if((result == -1 && (errno == ECONNRESET || errno == EPIPE)) ||
>>>> result == 0) {
>>>>               DBG("app died while being traced");
>>>>               retval = GET_SUBBUF_DIED;
>>>> @@ -84,20 +88,14 @@ int get_subbuffer(struct buffer_info *buf)
>>>>               goto end_rep;
>>>>       }
>>>>
>>>> -     if(!strcmp(rep_code, "OK")) {
>>>> +     if (!strcmp(rep_code, "OK")) {
>>>>               DBG("got subbuffer %s", buf->name);
>>>>               retval = GET_SUBBUF_OK;
>>>> -     }
>>>> -     else if(nth_token_is(received_msg, "END", 0) == 1) {
>>>> -             retval = GET_SUBBUF_DONE;
>>>> -             goto end_rep;
>>>> -     }
>>>> -     else if(!strcmp(received_msg, "NOTFOUND")) {
>>>> +     } else if(!strcmp(received_msg, "NOTFOUND")) {
>>>>               DBG("For buffer %s, the trace was not found. This
>>>> likely means it was destroyed by the user.", buf->name);
>>>>               retval = GET_SUBBUF_DIED;
>>>>               goto end_rep;
>>>> -     }
>>>> -     else {
>>>> +     } else {
>>>>               DBG("error getting subbuffer %s", buf->name);
>>>>               retval = -1;
>>>>       }
>>>> @@ -129,7 +127,7 @@ int put_subbuffer(struct buffer_info *buf)
>>>>               retval = -1;
>>>>               goto end;
>>>>       }
>>>> -     result = ustcomm_send_request(buf->conn, send_msg, &received_msg);
>>>> +     result = ustcomm_send_request(buf->app_sock, send_msg,
>>>> &received_msg);
>>>>       if(result < 0 && (errno == ECONNRESET || errno == EPIPE)) {
>>>>               retval = PUT_SUBBUF_DIED;
>>>>               goto end;
>>>> @@ -200,6 +198,7 @@ struct buffer_info *connect_buffer(struct
>>>> libustd_instance *instance, pid_t pid,
>>>>       char *received_msg;
>>>>       int result;
>>>>       struct shmid_ds shmds;
>>>> +     struct ustcomm_header header;
>>>>
>>>>       buf = (struct buffer_info *) zmalloc(sizeof(struct buffer_info));
>>>>       if(buf == NULL) {
>>>> @@ -207,18 +206,12 @@ struct buffer_info *connect_buffer(struct
>>>> libustd_instance *instance, pid_t pid,
>>>>               return NULL;
>>>>       }
>>>>
>>>> -     buf->conn = malloc(sizeof(struct ustcomm_connection));
>>>> -     if(buf->conn == NULL) {
>>>> -             ERR("add_buffer: insufficient memory");
>>>> -             free(buf);
>>>> -             return NULL;
>>>> -     }
>>>> -
>>>>       buf->name = bufname;
>>>>       buf->pid = pid;
>>>>
>>>> +     /* FIXME: Fix all the freeing and exit sequence from this
>>>> functions */
>>>>       /* connect to app */
>>>> -     result = ustcomm_connect_app(buf->pid, buf->conn);
>>>> +     result = ustcomm_connect_app(buf->pid, &buf->app_sock);
>>>>       if(result) {
>>>>               WARN("unable to connect to process, it probably died
>>>> before we were able to connect");
>>>>               return NULL;
>>>> @@ -229,7 +222,7 @@ struct buffer_info *connect_buffer(struct
>>>> libustd_instance *instance, pid_t pid,
>>>>               ERR("connect_buffer : asprintf failed (get_pidunique)");
>>>>               return NULL;
>>>>       }
>>>> -     result = ustcomm_send_request(buf->conn, send_msg, &received_msg);
>>>> +     result = ustcomm_send_request(buf->app_sock, send_msg,
>>>> &received_msg);
>>>>       free(send_msg);
>>>>       if(result == -1) {
>>>>               ERR("problem in ustcomm_send_request(get_pidunique)");
>>>> @@ -253,7 +246,7 @@ struct buffer_info *connect_buffer(struct
>>>> libustd_instance *instance, pid_t pid,
>>>>                   buf->name);
>>>>               return NULL;
>>>>       }
>>>> -     result = ustcomm_send_request(buf->conn, send_msg, &received_msg);
>>>> +     result = ustcomm_send_request(buf->app_sock, send_msg,
>>>> &received_msg);
>>>>       free(send_msg);
>>>>       if(result == -1) {
>>>>               ERR("problem in ustcomm_send_request(get_shmid)");
>>>> @@ -277,7 +270,7 @@ struct buffer_info *connect_buffer(struct
>>>> libustd_instance *instance, pid_t pid,
>>>>                   buf->name);
>>>>               return NULL;
>>>>       }
>>>> -     result = ustcomm_send_request(buf->conn, send_msg, &received_msg);
>>>> +     result = ustcomm_send_request(buf->app_sock, send_msg,
>>>> &received_msg);
>>>>       free(send_msg);
>>>>       if(result == -1) {
>>>>               ERR("problem in ustcomm_send_request(g_n_subbufs)");
>>>> @@ -301,7 +294,7 @@ struct buffer_info *connect_buffer(struct
>>>> libustd_instance *instance, pid_t pid,
>>>>                   buf->name);
>>>>               return NULL;
>>>>       }
>>>> -     result = ustcomm_send_request(buf->conn, send_msg, &received_msg);
>>>> +     result = ustcomm_send_request(buf->app_sock, send_msg,
>>>> &received_msg);
>>>>       free(send_msg);
>>>>       if(result == -1) {
>>>>               ERR("problem in ustcomm_send_request(get_subbuf_size)");
>>>> @@ -342,6 +335,32 @@ struct buffer_info *connect_buffer(struct
>>>> libustd_instance *instance, pid_t pid,
>>>>       }
>>>>       buf->memlen = shmds.shm_segsz;
>>>>
>>>> +     /* get buffer pipe fd */
>>>> +     memset(&header, 0, sizeof(header));
>>>> +     if (asprintf(&send_msg, "get_buffer_fd %s", buf->name) < 0) {
>>>> +             ERR("connect_buffer : asprintf failed (get_buffer_fd %s)",
>>>> +                 buf->name);
>>>> +             return NULL;
>>>> +     }
>>>> +     header.size = strlen(send_msg) + 1;
>>>> +     result = ustcomm_send(buf->app_sock, &header, send_msg);
>>>> +     free(send_msg);
>>>> +     if (result <= 0) {
>>>> +             ERR("ustcomm_send failed.");
>>>> +             return NULL;
>>>> +     }
>>>> +     result = ustcomm_recv_fd(buf->app_sock, &header, NULL,
>>>> &buf->pipe_fd);
>>>> +     if (result <= 0) {
>>>> +             ERR("ustcomm_recv_fd failed");
>>>> +             return NULL;
>>>> +     } else {
>>>> +             struct stat temp;
>>>> +             fstat(buf->pipe_fd, &temp);
>>>> +             if (!S_ISFIFO(temp.st_mode)) {
>>>> +                     ERR("Didn't receive a fifo from the app");
>>>> +                     return NULL;
>>>> +             }
>>>> +     }
>>>>       if(instance->callbacks->on_open_buffer)
>>>>              
>>>> instance->callbacks->on_open_buffer(instance->callbacks, buf);
>>>>
>>>> @@ -361,7 +380,7 @@ static void destroy_buffer(struct
>>>> libustd_callbacks *callbacks,
>>>>  {
>>>>       int result;
>>>>
>>>> -     result = ustcomm_close_app(buf->conn);
>>>> +     result = close(buf->app_sock);
>>>>       if(result == -1) {
>>>>               WARN("problem calling ustcomm_close_app");
>>>>       }
>>>> @@ -379,28 +398,31 @@ static void destroy_buffer(struct
>>>> libustd_callbacks *callbacks,
>>>>       if(callbacks->on_close_buffer)
>>>>               callbacks->on_close_buffer(callbacks, buf);
>>>>
>>>> -     free(buf->conn);
>>>>       free(buf);
>>>>  }
>>>>
>>>>  int consumer_loop(struct libustd_instance *instance, struct
>>>> buffer_info *buf)
>>>>  {
>>>> -     int result;
>>>> +     int result, read_result;
>>>> +     char read_buf;
>>>>
>>>>       pthread_cleanup_push(decrement_active_buffers, instance);
>>>>
>>>>       for(;;) {
>>>> +             read_result = read(buf->pipe_fd, &read_buf, 1);
>>>>               /* get the subbuffer */
>>>> -             result = get_subbuffer(buf);
>>>> -             if(result == -1) {
>>>> -                     ERR("error getting subbuffer");
>>>> -                     continue;
>>>> -             }
>>>> -             else if(result == GET_SUBBUF_DONE) {
>>>> -                     /* this is done */
>>>> -                     break;
>>>> -             }
>>>> -             else if(result == GET_SUBBUF_DIED) {
>>>> +             if (read_result == 1) {
>>>> +                     result = get_subbuffer(buf);
>>>> +                     if(result == -1) {
>>>> +                             ERR("error getting subbuffer");
>>>> +                             continue;
>>>> +                     } else if (result == GET_SUBBUF_DIED) {
>>>> +                            
>>>> finish_consuming_dead_subbuffer(instance->callbacks, buf);
>>>> +                             break;
>>>> +                     }
>>>> +             } else if ((read_result == -1 && (errno == ECONNRESET
>>>> || errno == EPIPE)) ||
>>>> +                        result == 0) {
>>>> +                     DBG("App died while being traced");
>>>>                      
>>>> finish_consuming_dead_subbuffer(instance->callbacks, buf);
>>>>                       break;
>>>>               }
>>>> @@ -541,64 +563,86 @@ int start_consuming_buffer(
>>>>
>>>>       return 0;
>>>>  }
>>>> +static void process_client_cmd(char *recvbuf, struct
>>>> libustd_instance *instance)
>>>> +{
>>>> +     if(!strncmp(recvbuf, "collect", 7)) {
>>>> +             pid_t pid;
>>>> +             char *bufname;
>>>> +             int result;
>>>> +
>>>> +             result = sscanf(recvbuf, "%*s %d %50as", &pid, &bufname);
>>>> +             if (result != 2) {
>>>> +                     ERR("parsing error: %s", recvbuf);
>>>> +                     goto free_bufname;
>>>> +             }
>>>> +
>>>> +             result = start_consuming_buffer(instance, pid, bufname);
>>>> +             if (result < 0) {
>>>> +                     ERR("error in add_buffer");
>>>> +                     goto free_bufname;
>>>> +             }
>>>> +
>>>> +     free_bufname:
>>>> +             free(bufname);
>>>> +     } else if(!strncmp(recvbuf, "exit", 4)) {
>>>> +             /* Only there to force poll to return */
>>>> +     } else {
>>>> +             WARN("unknown command: %s", recvbuf);
>>>> +     }
>>>> +}
>>>> +
>>>> +#define MAX_EVENTS 10
>>>>
>>>>  int libustd_start_instance(struct libustd_instance *instance)
>>>>  {
>>>> -     int result;
>>>> -     int timeout = -1;
>>>> +     struct ustcomm_sock *epoll_sock;
>>>> +     struct epoll_event events[MAX_EVENTS];
>>>> +     struct sockaddr addr;
>>>> +     int result, epoll_fd, accept_fd, nfds, i, addr_size, timeout;
>>>>
>>>>       if(!instance->is_init) {
>>>>               ERR("libustd instance not initialized");
>>>>               return 1;
>>>>       }
>>>> +     epoll_fd = instance->epoll_fd;
>>>> +
>>>> +     timeout = -1;
>>>>
>>>>       /* app loop */
>>>>       for(;;) {
>>>> -             char *recvbuf;
>>>> -
>>>> -             /* check for requests on our public socket */
>>>> -             result = ustcomm_ustd_recv_message(instance->comm,
>>>> &recvbuf, NULL, timeout);
>>>> -             if(result == -1 && errno == EINTR) {
>>>> +             nfds = epoll_wait(epoll_fd, events, MAX_EVENTS, timeout);
>>>> +             if (nfds == -1 && errno == EINTR) {
>>>>                       /* Caught signal */
>>>> +             } else if (nfds == -1) {
>>>> +                     ERR("epoll_wait");
>>>>               }
>>>> -             else if(result == -1) {
>>>> -                     ERR("error in ustcomm_ustd_recv_message");
>>>> -                     goto loop_end;
>>>> -             }
>>>> -             else if(result > 0) {
>>>> -                     if(!strncmp(recvbuf, "collect", 7)) {
>>>> -                             pid_t pid;
>>>> -                             char *bufname;
>>>> -                             int result;
>>>> -
>>>> -                             result = sscanf(recvbuf, "%*s %d
>>>> %50as", &pid, &bufname);
>>>> -                             if(result != 2) {
>>>> -                                     ERR("parsing error: %s", recvbuf);
>>>> -                                     goto free_bufname;
>>>> -                             }
>>>>
>>>> -                             result =
>>>> start_consuming_buffer(instance, pid, bufname);
>>>> -                             if(result < 0) {
>>>> -                                     ERR("error in add_buffer");
>>>> -                                     goto free_bufname;
>>>> +             for (i = 0; i < nfds; ++i) {
>>>> +                     epoll_sock = (struct ustcomm_sock
>>>> *)events[i].data.ptr;
>>>> +                     if (epoll_sock == instance->listen_sock) {
>>>> +                             addr_size = sizeof(struct sockaddr);
>>>> +                             accept_fd = accept(epoll_sock->fd,
>>>> +                                                &addr,
>>>> +                                                (socklen_t
>>>> *)&addr_size);
>>>> +                             if (accept_fd == -1) {
>>>> +                                     ERR("accept failed\n");
>>>> +                             }
>>>> +                             ustcomm_init_sock(accept_fd, epoll_fd,
>>>> +                                              &instance->connections);
>>>> +                     } else {
>>>> +                             char *msg = NULL;
>>>> +                             result =
>>>> recv_message_conn(epoll_sock->fd, &msg);
>>>> +                             if (result == 0) {
>>>> +                                     ustcomm_del_sock(epoll_sock, 0);
>>>> +                             } else if (msg) {
>>>> +                                     process_client_cmd(msg, instance);
>>>> +                                     free(msg);
>>>>                               }
>>>>
>>>> -                             free_bufname:
>>>> -                             free(bufname);
>>>> -                     }
>>>> -                     else if(!strncmp(recvbuf, "exit", 4)) {
>>>> -                             /* Only there to force poll to return */
>>>> -                     }
>>>> -                     else {
>>>> -                             WARN("unknown command: %s", recvbuf);
>>>>                       }
>>>> -
>>>> -                     free(recvbuf);
>>>>               }
>>>>
>>>> -             loop_end:
>>>> -
>>>> -             if(instance->quit_program) {
>>>> +             if (instance->quit_program) {
>>>>                       pthread_mutex_lock(&instance->mutex);
>>>>                       if(instance->active_buffers == 0) {
>>>>                               pthread_mutex_unlock(&instance->mutex);
>>>> @@ -617,14 +661,16 @@ int libustd_start_instance(struct
>>>> libustd_instance *instance)
>>>>       return 0;
>>>>  }
>>>>
>>>> +/* FIXME: threads and connections !? */
>>>>  void libustd_delete_instance(struct libustd_instance *instance)
>>>>  {
>>>> -     if(instance->is_init)
>>>> -             ustcomm_fini_ustd(instance->comm);
>>>> +     if (instance->is_init) {
>>>> +             ustcomm_del_named_sock(instance->listen_sock, 0);
>>>> +             close(instance->epoll_fd);
>>>> +     }
>>>>
>>>>       pthread_mutex_destroy(&instance->mutex);
>>>>       free(instance->sock_path);
>>>> -     free(instance->comm);
>>>>       free(instance);
>>>>  }
>>>>
>>>> @@ -669,17 +715,13 @@ int libustd_stop_instance(struct
>>>> libustd_instance *instance, int send_msg)
>>>>       return 0;
>>>>  }
>>>>
>>>> -struct libustd_instance *libustd_new_instance(
>>>> -     struct libustd_callbacks *callbacks, char *sock_path)
>>>> +struct libustd_instance
>>>> +*libustd_new_instance(struct libustd_callbacks *callbacks,
>>>> +                   char *sock_path)
>>>>  {
>>>>       struct libustd_instance *instance =
>>>>               zmalloc(sizeof(struct libustd_instance));
>>>> -     if(!instance)
>>>> -             return NULL;
>>>> -
>>>> -     instance->comm = malloc(sizeof(struct ustcomm_ustd));
>>>> -     if(!instance->comm) {
>>>> -             free(instance);
>>>> +     if(!instance) {
>>>>               return NULL;
>>>>       }
>>>>
>>>> @@ -689,18 +731,75 @@ struct libustd_instance *libustd_new_instance(
>>>>       instance->active_buffers = 0;
>>>>       pthread_mutex_init(&instance->mutex, NULL);
>>>>
>>>> -     if(sock_path)
>>>> +     if (sock_path) {
>>>>               instance->sock_path = strdup(sock_path);
>>>> -     else
>>>> +     } else {
>>>>               instance->sock_path = NULL;
>>>> +     }
>>>>
>>>>       return instance;
>>>>  }
>>>>
>>>> +static int init_ustd_socket(struct libustd_instance *instance)
>>>> +{
>>>> +     char *name;
>>>> +
>>>> +     if (instance->sock_path) {
>>>> +             if (asprintf(&name, "%s", instance->sock_path) < 0) {
>>>> +                     ERR("ustcomm_init_ustd : asprintf failed
>>>> (sock_path %s)",
>>>> +                         instance->sock_path);
>>>> +                     return -1;
>>>> +             }
>>>> +     } else {
>>>> +             int result;
>>>> +
>>>> +             /* Only check if socket dir exists if we are using the
>>>> default directory */
>>>> +             result = ensure_dir_exists(SOCK_DIR);
>>>> +             if (result == -1) {
>>>> +                     ERR("Unable to create socket directory %s",
>>>> SOCK_DIR);
>>>> +                     return -1;
>>>> +             }
>>>> +
>>>> +             if (asprintf(&name, "%s/%s", SOCK_DIR, "ustd") < 0) {
>>>> +                     ERR("ustcomm_init_ustd : asprintf failed
>>>> (%s/ustd)",
>>>> +                         SOCK_DIR);
>>>> +                     return -1;
>>>> +             }
>>>> +     }
>>>> +
>>>> +     /* Set up epoll */
>>>> +     instance->epoll_fd = epoll_create(MAX_EVENTS);
>>>> +     if (instance->epoll_fd == -1) {
>>>> +             ERR("epoll_create failed, start instance bailing");
>>>> +             goto free_name;
>>>> +     }
>>>> +
>>>> +     /* Create the named socket */
>>>> +     instance->listen_sock = ustcomm_init_named_socket(name,
>>>> +                                                      
>>>> instance->epoll_fd);
>>>> +     if(!instance->listen_sock) {
>>>> +             ERR("error initializing named socket at %s", name);
>>>> +             goto close_epoll;
>>>> +     }
>>>> +
>>>> +     INIT_LIST_HEAD(&instance->connections);
>>>> +
>>>> +     free(name);
>>>> +
>>>> +     return 0;
>>>> +
>>>> +close_epoll:
>>>> +     close(instance->epoll_fd);
>>>> +free_name:
>>>> +     free(name);
>>>> +
>>>> +     return -1;
>>>> +}
>>>> +
>>>>  int libustd_init_instance(struct libustd_instance *instance)
>>>>  {
>>>>       int result;
>>>> -     result = ustcomm_init_ustd(instance->comm, instance->sock_path);
>>>> +     result = init_ustd_socket(instance);
>>>>       if(result == -1) {
>>>>               ERR("failed to initialize socket");
>>>>               return 1;
> 
>>

- -- 
David Goulet
LTTng project, DORSAL Lab.

1024D/16BD8563
BE3C 672B 9331 9796 291A  14C6 4AF7 C14B 16BD 8563
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