sysdeps/unix/sysv/linux/sigprocmask.c

   1 /* Copyright (C) 1997-2001,2003,2004,2006 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, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <signal.h>
  20 #include <string.h>     /* Neede for string function builtin redirection.  */
  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
  30 /* The variable is shared between all wrappers around signal handling
  31    functions which have RT equivalents.  The definition is in sigaction.c.  */
  32 extern int __libc_missing_rt_sigs;
  33
  34
  35 /* Get and/or change the set of blocked signals.  */
  36 int
  37 __sigprocmask (how, set, oset)
  38      int how;
  39      const sigset_t *set;
  40      sigset_t *oset;
  41 {
  42 #ifdef SIGCANCEL
  43   sigset_t local_newmask;
  44
  45   /* The only thing we have to make sure here is that SIGCANCEL and
  46      SIGSETXID are not blocked.  */
  47   if (set != NULL
  48       && (__builtin_expect (__sigismember (set, SIGCANCEL), 0)
  49 # ifdef SIGSETXID
  50           || __builtin_expect (__sigismember (set, SIGSETXID), 0)
  51 # endif
  52           ))
  53     {
  54       local_newmask = *set;
  55       __sigdelset (&local_newmask, SIGCANCEL);
  56 # ifdef SIGSETXID
  57       __sigdelset (&local_newmask, SIGSETXID);
  58 # endif
  59       set = &local_newmask;
  60     }
  61 #endif
  62
  63 #if __ASSUME_REALTIME_SIGNALS > 0
  64   return INLINE_SYSCALL (rt_sigprocmask, 4, how, CHECK_SIGSET_NULL_OK (set),
  65                          CHECK_SIGSET_NULL_OK (oset), _NSIG / 8);
  66 #else
  67 # ifdef __NR_rt_sigprocmask
  68   /* First try the RT signals.  */
  69   if (!__libc_missing_rt_sigs)
  70     {
  71       /* XXX The size argument hopefully will have to be changed to the
  72          real size of the user-level sigset_t.  */
  73       int saved_errno = errno;
  74       int result = INLINE_SYSCALL (rt_sigprocmask, 4, how,
  75                                    CHECK_SIGSET_NULL_OK (set),
  76                                    CHECK_SIGSET_NULL_OK (oset), _NSIG / 8);
  77
  78       if (result >= 0 || errno != ENOSYS)
  79         return result;
  80
  81       __set_errno (saved_errno);
  82       __libc_missing_rt_sigs = 1;
  83     }
  84 # endif
  85
  86   return INLINE_SYSCALL (sigprocmask, 3, how, CHECK_SIGSET_NULL_OK (set),
  87                          CHECK_SIGSET_NULL_OK (oset));
  88 #endif
  89 }
  90 weak_alias (__sigprocmask, sigprocmask)