[lttng-dev] how to get relayd pid

[Anand Neeli]

Phil,
Thanks a lot for the code

Anand Neeli

On Wed, Apr 8, 2015 at 2:05 AM, Philippe Proulx <eeppeliteloop at gmail.com>
wrote:

> Anand,
>
> On Tue, Apr 7, 2015 at 4:19 PM, Anand Neeli <anand.neeli at gmail.com> wrote:
> > For C
>
> lttng-relayd does not write its PID to a file.
>
> For C, here's the programmatic way of getting the PID of the first
> lttng-relayd process found (inspired by [1]):
>
>     #include <stdlib.h>
>     #include <stdio.h>
>     #include <string.h>
>     #include <dirent.h>
>
>     /* checks if the string is purely an integer
>      * we can do it with `strtol' also
>      */
>     int check_if_number (char *str)
>     {
>       int i;
>       for (i=0; str[i] != '\0'; i++)
>       {
>         if (!isdigit (str[i]))
>         {
>           return 0;
>         }
>       }
>       return 1;
>     }
>
>     #define MAX_BUF 1024
>     #define PID_LIST_BLOCK 32
>
>     int *pidof (char *pname)
>     {
>       DIR *dirp;
>       FILE *fp;
>       struct dirent *entry;
>       int *pidlist, pidlist_index = 0, pidlist_realloc_count = 1;
>       char path[MAX_BUF], read_buf[MAX_BUF];
>
>       dirp = opendir ("/proc/");
>       if (dirp == NULL)
>       {
>         perror ("Fail");
>         return NULL;
>       }
>
>       pidlist = malloc (sizeof (int) * PID_LIST_BLOCK);
>       if (pidlist == NULL)
>       {
>         return NULL;
>       }
>
>       while ((entry = readdir (dirp)) != NULL)
>       {
>         if (check_if_number (entry->d_name))
>         {
>           strcpy (path, "/proc/");
>           strcat (path, entry->d_name);
>           strcat (path, "/comm");
>
>           /* A file may not exist, it may have been removed.
>            * dut to termination of the process. Actually we need to
>            * make sure the error is actually file does not exist to
>            * be accurate.
>            */
>           fp = fopen (path, "r");
>           if (fp != NULL)
>           {
>             fscanf (fp, "%s", read_buf);
>             if (strcmp (read_buf, pname) == 0)
>             {
>               /* add to list and expand list if needed */
>               pidlist[pidlist_index++] = atoi (entry->d_name);
>               if (pidlist_index == PID_LIST_BLOCK * pidlist_realloc_count)
>               {
>                 pidlist_realloc_count++;
>                 pidlist = realloc (pidlist, sizeof (int) *
> PID_LIST_BLOCK * pidlist_realloc_count); //Error check todo
>                 if (pidlist == NULL)
>                 {
>                   return NULL;
>                 }
>               }
>             }
>             fclose (fp);
>           }
>         }
>       }
>
>
>       closedir (dirp);
>       pidlist[pidlist_index] = -1; /* indicates end of list */
>       return pidlist;
>     }
>
>     int main (void)
>     {
>       int *list = pidof("lttng-relayd");
>
>       if (!list || list[0] == -1) {
>         fprintf(stderr, "lttng-relayd is not running!\n");
>         free(list);
>         return 1;
>       }
>
>       printf("PID of first lttng-relayd found: %d\n", list[0]);
>       free(list);
>
>       return 0;
>     }
>
> [1]
> http://phoxis.org/2013/09/13/find-process-ids-of-a-running-process-by-name/
>
> Hope it helps,
> Phil
>
> >
> >
> >
> >
> > On Wed, Apr 8, 2015 at 1:45 AM, Philippe Proulx <eeppeliteloop at gmail.com
> >
> > wrote:
> >>
> >> Anand,
> >>
> >> On Tue, Apr 7, 2015 at 4:07 PM, Anand Neeli <anand.neeli at gmail.com>
> wrote:
> >> >
> >> > Hi All,
> >> > Is there any better way of getting lttng-relayd PID programmatically?
> >> >
> >> > like sessiond pid is in /var/run/lttng/lttng-sessiond.pid,  is there
> any
> >> > similar way to get relayd PID?
> >>
> >> For which language?
> >>
> >> Phil
> >> >
> >> >
> >> > Thanks,
> >> > Anand Neeli
> >> >
> >> > _______________________________________________
> >> > lttng-dev mailing list
> >> > lttng-dev at lists.lttng.org
> >> > http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
> >> >
> >
> >
>
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