sysdeps/unix/sysv/linux/sigsuspend.c

   1 /* Copyright (C) 1996,1997,1998,1999,2000,2002 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, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #include <signal.h>
  21 #include <unistd.h>
  22
  23 #include <sysdep.h>
  24 #include <sys/syscall.h>
  25 #include <bp-checks.h>
  26
  27 #include "kernel-features.h"
  28
  29 extern int __syscall_sigsuspend (int, unsigned long int, unsigned long int);
  30 extern int __syscall_rt_sigsuspend (const sigset_t *__unbounded, size_t);
  31
  32
  33 /* The variable is shared between all wrappers around signal handling
  34    functions which have RT equivalents.  The definition is in sigaction.c.  */
  35 extern int __libc_missing_rt_sigs;
  36
  37
  38 /* Change the set of blocked signals to SET,
  39    wait until a signal arrives, and restore the set of blocked signals.  */
  40 int
  41 __sigsuspend (set)
  42      const sigset_t *set;
  43 {
  44 #if __ASSUME_REALTIME_SIGNALS
  45   return INLINE_SYSCALL (rt_sigsuspend, 2, CHECK_SIGSET (set), _NSIG / 8);
  46 #else
  47 # ifdef __NR_rt_sigsuspend
  48   /* First try the RT signals.  */
  49   if (!__libc_missing_rt_sigs)
  50     {
  51       /* XXX The size argument hopefully will have to be changed to the
  52          real size of the user-level sigset_t.  */
  53       int saved_errno = errno;
  54       int result = INLINE_SYSCALL (rt_sigsuspend, 2,
  55                                    CHECK_SIGSET (set), _NSIG / 8);
  56       if (result >= 0 || errno != ENOSYS)
  57         return result;
  58
  59       __set_errno (saved_errno);
  60       __libc_missing_rt_sigs = 1;
  61     }
  62 # endif
  63
  64   return INLINE_SYSCALL (sigsuspend, 3, 0, 0, set->__val[0]);
  65 #endif
  66 }
  67 libc_hidden_def (__sigsuspend)
  68 weak_alias (__sigsuspend, sigsuspend)