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

   1 /* pthread_setname_np -- Set  thread name.  Linux version
   2    Copyright (C) 2010 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 not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <pthreadP.h>
  23 #include <stdio.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26 #include <sys/prctl.h>
  27
  28 #include <not-cancel.h>
  29
  30
  31 int
  32 pthread_setname_np (th, name)
  33      pthread_t th;
  34      const char *name;
  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   size_t name_len = strlen (name);
  42   if (name_len >= TASK_COMM_LEN)
  43     return ERANGE;
  44
  45   if (pd == THREAD_SELF)
  46     return prctl (PR_SET_NAME, name) ? errno : 0;
  47
  48 #define FMT "/proc/self/task/%u/comm"
  49   char fname[sizeof (FMT) + 8];
  50   sprintf (fname, FMT, (unsigned int) pd->tid);
  51
  52   int fd = open_not_cancel_2 (fname, O_RDWR);
  53   if (fd == -1)
  54     return errno;
  55
  56   int res = 0;
  57   ssize_t n = TEMP_FAILURE_RETRY (write_not_cancel (fd, name, name_len));
  58   if (n < 0)
  59     res = errno;
  60   else if (n != name_len)
  61     res = EIO;
  62
  63   close_not_cancel_no_status (fd);
  64
  65   return res;
  66 }