sysdeps/unix/sysv/linux/sigsuspend.c

   1 /* Copyright (C) 1996,1997,1998,1999,2000,2002,2003,2006
   2         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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <signal.h>
  22 #include <unistd.h>
  23
  24 #include <sysdep-cancel.h>
  25 #include <sys/syscall.h>
  26 #include <bp-checks.h>
  27
  28 #include <kernel-features.h>
  29
  30
  31 #if !__ASSUME_REALTIME_SIGNALS
  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 static int
  38 do_sigsuspend (const sigset_t *set)
  39 {
  40 # ifdef __NR_rt_sigsuspend
  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,
  48                                    CHECK_SIGSET (set), _NSIG / 8);
  49       if (result >= 0 || errno != ENOSYS)
  50         return result;
  51
  52       __set_errno (saved_errno);
  53       __libc_missing_rt_sigs = 1;
  54     }
  55 # endif
  56
  57   return INLINE_SYSCALL (sigsuspend, 3, 0, 0, set->__val[0]);
  58 }
  59 #endif
  60
  61 /* Change the set of blocked signals to SET,
  62    wait until a signal arrives, and restore the set of blocked signals.  */
  63 int
  64 __sigsuspend (set)
  65      const sigset_t *set;
  66 {
  67 #if __ASSUME_REALTIME_SIGNALS
  68   if (SINGLE_THREAD_P)
  69     return INLINE_SYSCALL (rt_sigsuspend, 2, CHECK_SIGSET (set), _NSIG / 8);
  70
  71   int oldtype = LIBC_CANCEL_ASYNC ();
  72
  73   int result = INLINE_SYSCALL (rt_sigsuspend, 2, CHECK_SIGSET (set),
  74                                _NSIG / 8);
  75
  76   LIBC_CANCEL_RESET (oldtype);
  77
  78   return result;
  79 #else
  80   if (SINGLE_THREAD_P)
  81     return do_sigsuspend (set);
  82
  83   int oldtype = LIBC_CANCEL_ASYNC ();
  84
  85   int result = do_sigsuspend (set);
  86
  87   LIBC_CANCEL_RESET (oldtype);
  88
  89   return result;
  90 #endif
  91 }
  92 libc_hidden_def (__sigsuspend)
  93 weak_alias (__sigsuspend, sigsuspend)
  94 strong_alias (__sigsuspend, __libc_sigsuspend)