sysdeps/unix/sysv/linux/pthread_sigqueue.c

   1 /* Copyright (C) 2009-2017 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2009.
   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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <signal.h>
  21 #include <string.h>
  22 #include <unistd.h>
  23 #include <pthreadP.h>
  24 #include <tls.h>
  25 #include <sysdep.h>
  26
  27
  28 int
  29 pthread_sigqueue (pthread_t threadid, int signo, const union sigval value)
  30 {
  31 #ifdef __NR_rt_tgsigqueueinfo
  32   struct pthread *pd = (struct pthread *) threadid;
  33
  34   /* Make sure the descriptor is valid.  */
  35   if (DEBUGGING_P && INVALID_TD_P (pd))
  36     /* Not a valid thread handle.  */
  37     return ESRCH;
  38
  39   /* Force load of pd->tid into local variable or register.  Otherwise
  40      if a thread exits between ESRCH test and tgkill, we might return
  41      EINVAL, because pd->tid would be cleared by the kernel.  */
  42   pid_t tid = atomic_forced_read (pd->tid);
  43   if (__glibc_unlikely (tid <= 0))
  44     /* Not a valid thread handle.  */
  45     return ESRCH;
  46
  47   /* Disallow sending the signal we use for cancellation, timers,
  48      for the setxid implementation.  */
  49   if (signo == SIGCANCEL || signo == SIGTIMER || signo == SIGSETXID)
  50     return EINVAL;
  51
  52   pid_t pid = getpid ();
  53
  54   /* Set up the siginfo_t structure.  */
  55   siginfo_t info;
  56   memset (&info, '\0', sizeof (siginfo_t));
  57   info.si_signo = signo;
  58   info.si_code = SI_QUEUE;
  59   info.si_pid = pid;
  60   info.si_uid = getuid ();
  61   info.si_value = value;
  62
  63   /* We have a special syscall to do the work.  */
  64   INTERNAL_SYSCALL_DECL (err);
  65
  66   int val = INTERNAL_SYSCALL_CALL (rt_tgsigqueueinfo, err, pid, tid, signo,
  67                                    &info);
  68   return (INTERNAL_SYSCALL_ERROR_P (val, err)
  69           ? INTERNAL_SYSCALL_ERRNO (val, err) : 0);
  70 #else
  71   return ENOSYS;
  72 #endif
  73 }