1  /* pthread_setname_np -- Set  thread name.  Linux version
       2     Copyright (C) 2010-2023 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 <https://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_setname_np (pthread_t th, const char *name)
      32  {
      33    const struct pthread *pd = (const struct pthread *) th;
      34  
      35    /* Unfortunately the kernel headers do not export the TASK_COMM_LEN
      36       macro.  So we have to define it here.  */
      37  #define TASK_COMM_LEN 16
      38    size_t name_len = strlen (name);
      39    if (name_len >= TASK_COMM_LEN)
      40      return ERANGE;
      41  
      42    if (pd == THREAD_SELF)
      43      return __prctl (PR_SET_NAME, name) ? errno : 0;
      44  
      45  #define FMT "/proc/self/task/%u/comm"
      46    char fname[sizeof (FMT) + 8];
      47    sprintf (fname, FMT, (unsigned int) pd->tid);
      48  
      49    int fd = __open64_nocancel (fname, O_RDWR);
      50    if (fd == -1)
      51      return errno;
      52  
      53    int res = 0;
      54    ssize_t n = TEMP_FAILURE_RETRY (__write_nocancel (fd, name, name_len));
      55    if (n < 0)
      56      res = errno;
      57    else if (n != name_len)
      58      res = EIO;
      59  
      60    __close_nocancel_nostatus (fd);
      61  
      62    return res;
      63  }
      64  versioned_symbol (libc, __pthread_setname_np, pthread_setname_np,
      65                    GLIBC_2_34);
      66  
      67  #if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_12, GLIBC_2_34)
      68  compat_symbol (libpthread, __pthread_setname_np, pthread_setname_np,
      69                 GLIBC_2_12);
      70  #endif