sysdeps/unix/sysv/linux/sigsuspend.c

   1 /* Copyright (C) 1996, 1997, 1998, 1999 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 Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    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    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 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
  26 #include "kernel-features.h"
  27
  28 extern int __syscall_sigsuspend (int, unsigned long int, unsigned long int);
  29 extern int __syscall_rt_sigsuspend (const sigset_t *, size_t);
  30
  31
  32 /* The variable is shared between all wrappers around signal handling
  33    functions which have RT equivalents.  The definition is in sigaction.c.  */
  34 extern int __libc_missing_rt_sigs;
  35
  36
  37 /* Change the set of blocked signals to SET,
  38    wait until a signal arrives, and restore the set of blocked signals.  */
  39 int
  40 __sigsuspend (set)
  41      const sigset_t *set;
  42 {
  43 #if __ASSUME_REALTIME_SIGNALS
  44   return INLINE_SYSCALL (rt_sigsuspend, 2, set, _NSIG / 8);
  45 #else
  46 # ifdef __NR_rt_sigsuspend
  47   /* First try the RT signals.  */
  48   if (!__libc_missing_rt_sigs)
  49     {
  50       /* XXX The size argument hopefully will have to be changed to the
  51          real size of the user-level sigset_t.  */
  52       int saved_errno = errno;
  53       int result = INLINE_SYSCALL (rt_sigsuspend, 2, set, _NSIG / 8);
  54
  55       if (result >= 0 || errno != ENOSYS)
  56         return result;
  57
  58       __set_errno (saved_errno);
  59       __libc_missing_rt_sigs = 1;
  60     }
  61 # endif
  62
  63   return INLINE_SYSCALL (sigsuspend, 3, 0, 0, set->__val[0]);
  64 #endif
  65 }
  66 weak_alias (__sigsuspend, sigsuspend)