nptl/sysdeps/unix/sysv/linux/pthread_getname.c

   1 /* pthread_getname_np -- Get  thread name.  Linux version
   2    Copyright (C) 2010-2014 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If
  17    not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <pthreadP.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25 #include <sys/prctl.h>
  26
  27 #include <not-cancel.h>
  28
  29
  30 int
  31 pthread_getname_np (th, buf, len)
  32      pthread_t th;
  33      char *buf;
  34      size_t len;
  35 {
  36   const struct pthread *pd = (const struct pthread *) th;
  37
  38   /* Unfortunately the kernel headers do not export the TASK_COMM_LEN
  39      macro.  So we have to define it here.  */
  40 #define TASK_COMM_LEN 16
  41   if (len < TASK_COMM_LEN)
  42     return ERANGE;
  43
  44   if (pd == THREAD_SELF)
  45     return prctl (PR_GET_NAME, buf) ? errno : 0;
  46
  47 #define FMT "/proc/self/task/%u/comm"
  48   char fname[sizeof (FMT) + 8];
  49   sprintf (fname, FMT, (unsigned int) pd->tid);
  50
  51   int fd = open_not_cancel_2 (fname, O_RDONLY);
  52   if (fd == -1)
  53     return errno;
  54
  55   int res = 0;
  56   ssize_t n = TEMP_FAILURE_RETRY (read_not_cancel (fd, buf, len));
  57   if (n < 0)
  58     res = errno;
  59   else
  60     {
  61       if (buf[n - 1] == '\n')
  62         buf[n - 1] = '\0';
  63       else if (n == len)
  64         res = ERANGE;
  65       else
  66         buf[n] = '\0';
  67     }
  68
  69   close_not_cancel_no_status (fd);
  70
  71   return res;
  72 }