nptl/pthread_kill.c

   1 /* Send a signal to a specific pthread.  Stub version.
   2    Copyright (C) 2014-2021 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
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <unistd.h>
  20 #include <pthreadP.h>
  21 #include <shlib-compat.h>
  22
  23 int
  24 __pthread_kill_internal (pthread_t threadid, int signo)
  25 {
  26   pid_t tid;
  27   struct pthread *pd = (struct pthread *) threadid;
  28
  29   if (pd == THREAD_SELF)
  30     /* It is a special case to handle raise() implementation after a vfork
  31        call (which does not update the PD tid field).  */
  32     tid = INLINE_SYSCALL_CALL (gettid);
  33   else
  34     /* Force load of pd->tid into local variable or register.  Otherwise
  35        if a thread exits between ESRCH test and tgkill, we might return
  36        EINVAL, because pd->tid would be cleared by the kernel.  */
  37     tid = atomic_forced_read (pd->tid);
  38
  39   int val;
  40   if (__glibc_likely (tid > 0))
  41     {
  42       pid_t pid = __getpid ();
  43
  44       val = INTERNAL_SYSCALL_CALL (tgkill, pid, tid, signo);
  45       val = (INTERNAL_SYSCALL_ERROR_P (val)
  46             ? INTERNAL_SYSCALL_ERRNO (val) : 0);
  47     }
  48   else
  49     val = ESRCH;
  50
  51   return val;
  52 }
  53
  54 int
  55 __pthread_kill (pthread_t threadid, int signo)
  56 {
  57   /* Disallow sending the signal we use for cancellation, timers,
  58      for the setxid implementation.  */
  59   if (__is_internal_signal (signo))
  60     return EINVAL;
  61
  62   return __pthread_kill_internal (threadid, signo);
  63 }
  64 /* Some architectures (for instance arm) might pull raise through libgcc, so
  65    avoid the symbol version if it ends up being used on ld.so.  */
  66 #if !IS_IN(rtld)
  67 libc_hidden_def (__pthread_kill)
  68 versioned_symbol (libc, __pthread_kill, pthread_kill, GLIBC_2_34);
  69
  70 # if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_34)
  71 compat_symbol (libc, __pthread_kill, pthread_kill, GLIBC_2_0);
  72 # endif
  73 #endif