sysdeps/unix/sysv/linux/sigsuspend.c

   1 /* Copyright (C) 1996, 1997, 1998 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 extern int __syscall_sigsuspend (int, unsigned long int, unsigned long int);
  27 extern int __syscall_rt_sigsuspend (const sigset_t *, size_t);
  28
  29
  30 /* The variable is shared between all wrappers around signal handling
  31    functions which have RT equivalents.  */
  32 int __libc_missing_rt_sigs;
  33
  34
  35 /* Change the set of blocked signals to SET,
  36    wait until a signal arrives, and restore the set of blocked signals.  */
  37 int
  38 __sigsuspend (set)
  39      const sigset_t *set;
  40 {
  41   /* First try the RT signals.  */
  42   if (!__libc_missing_rt_sigs)
  43     {
  44       /* XXX The size argument hopefully will have to be changed to the
  45          real size of the user-level sigset_t.  */
  46       int saved_errno = errno;
  47       int result = INLINE_SYSCALL (rt_sigsuspend, 2, set, _NSIG / 8);
  48
  49       if (result >= 0 || errno != ENOSYS)
  50         return result;
  51
  52       __set_errno (saved_errno);
  53       __libc_missing_rt_sigs = 1;
  54     }
  55
  56   return INLINE_SYSCALL (sigsuspend, 3, 0, 0, set->__val[0]);
  57 }
  58 weak_alias (__sigsuspend, sigsuspend)