1  /* Copyright (C) 2009-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <errno.h>
      19  #include <signal.h>
      20  #include <string.h>
      21  #include <unistd.h>
      22  #include <pthreadP.h>
      23  #include <tls.h>
      24  #include <sysdep.h>
      25  #include <shlib-compat.h>
      26  
      27  int
      28  __pthread_sigqueue (pthread_t threadid, int signo, const union sigval value)
      29  {
      30  #ifdef __NR_rt_tgsigqueueinfo
      31    struct pthread *pd = (struct pthread *) threadid;
      32  
      33    /* Force load of pd->tid into local variable or register.  Otherwise
      34       if a thread exits between ESRCH test and tgkill, we might return
      35       EINVAL, because pd->tid would be cleared by the kernel.  */
      36    pid_t tid = atomic_forced_read (pd->tid);
      37    if (__glibc_unlikely (tid <= 0))
      38      /* Not a valid thread handle.  */
      39      return ESRCH;
      40  
      41    /* Disallow sending the signal we use for cancellation, timers,
      42       for the setxid implementation.  */
      43    if (signo == SIGCANCEL || signo == SIGTIMER || signo == SIGSETXID)
      44      return EINVAL;
      45  
      46    pid_t pid = getpid ();
      47  
      48    /* Set up the siginfo_t structure.  */
      49    siginfo_t info;
      50    memset (&info, '\0', sizeof (siginfo_t));
      51    info.si_signo = signo;
      52    info.si_code = SI_QUEUE;
      53    info.si_pid = pid;
      54    info.si_uid = __getuid ();
      55    info.si_value = value;
      56  
      57    /* We have a special syscall to do the work.  */
      58    int val = INTERNAL_SYSCALL_CALL (rt_tgsigqueueinfo, pid, tid, signo,
      59  				   &info);
      60    return (INTERNAL_SYSCALL_ERROR_P (val)
      61  	  ? INTERNAL_SYSCALL_ERRNO (val) : 0);
      62  #else
      63    return ENOSYS;
      64  #endif
      65  }
      66  versioned_symbol (libc, __pthread_sigqueue, pthread_sigqueue, GLIBC_2_34);
      67  
      68  #if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_11, GLIBC_2_34)
      69  compat_symbol (libpthread, __pthread_sigqueue, pthread_sigqueue, GLIBC_2_11);
      70  #endif