1  /* pthread_getname_np -- Get  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  #include <not-cancel.h>
      27  #include <shlib-compat.h>
      28  
      29  int
      30  __pthread_getname_np (pthread_t th, char *buf, size_t len)
      31  {
      32    const struct pthread *pd = (const struct pthread *) th;
      33  
      34    /* Unfortunately the kernel headers do not export the TASK_COMM_LEN
      35       macro.  So we have to define it here.  */
      36  #define TASK_COMM_LEN 16
      37    if (len < TASK_COMM_LEN)
      38      return ERANGE;
      39  
      40    if (pd == THREAD_SELF)
      41      return __prctl (PR_GET_NAME, buf) ? errno : 0;
      42  
      43  #define FMT "/proc/self/task/%u/comm"
      44    char fname[sizeof (FMT) + 8];
      45    sprintf (fname, FMT, (unsigned int) pd->tid);
      46  
      47    int fd = __open64_nocancel (fname, O_RDONLY);
      48    if (fd == -1)
      49      return errno;
      50  
      51    int res = 0;
      52    ssize_t n = TEMP_FAILURE_RETRY (__read_nocancel (fd, buf, len));
      53    if (n < 0)
      54      res = errno;
      55    else
      56      {
      57        if (buf[n - 1] == '\n')
      58  	buf[n - 1] = '\0';
      59        else if (n == len)
      60  	res = ERANGE;
      61        else
      62  	buf[n] = '\0';
      63      }
      64  
      65    __close_nocancel_nostatus (fd);
      66  
      67    return res;
      68  }
      69  versioned_symbol (libc, __pthread_getname_np, pthread_getname_np,
      70  		  GLIBC_2_34);
      71  
      72  #if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_12, GLIBC_2_34)
      73  compat_symbol (libpthread, __pthread_getname_np, pthread_getname_np,
      74  	       GLIBC_2_12);
      75  #endif