sysdeps/unix/sysv/linux/sigprocmask.c

   1 /* Copyright (C) 1997-2001,2003,2004 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 <string.h>     /* Neede for string function builtin redirection.  */
  22 #include <unistd.h>
  23
  24 #include <sysdep.h>
  25 #include <sys/syscall.h>
  26 #include <bp-checks.h>
  27
  28 #include "kernel-features.h"
  29
  30
  31 /* The variable is shared between all wrappers around signal handling
  32    functions which have RT equivalents.  The definition is in sigaction.c.  */
  33 extern int __libc_missing_rt_sigs;
  34
  35
  36 /* Get and/or change the set of blocked signals.  */
  37 int
  38 __sigprocmask (how, set, oset)
  39      int how;
  40      const sigset_t *set;
  41      sigset_t *oset;
  42 {
  43 #ifdef SIGCANCEL
  44   sigset_t local_newmask;
  45
  46   /* The only thing we have to make sure here is that SIGCANCEL and
  47      SIGSETXID are not blocked.  */
  48   if (set != NULL
  49       && (__builtin_expect (__sigismember (set, SIGCANCEL), 0)
  50 # ifdef SIGSETXID
  51           || __builtin_expect (__sigismember (set, SIGSETXID), 0)
  52 # endif
  53           ))
  54     {
  55       local_newmask = *set;
  56       __sigdelset (&local_newmask, SIGCANCEL);
  57 # ifdef SIGSETXID
  58       __sigdelset (&local_newmask, SIGSETXID);
  59 # endif
  60       set = &local_newmask;
  61     }
  62 #endif
  63
  64 #if __ASSUME_REALTIME_SIGNALS > 0
  65   return INLINE_SYSCALL (rt_sigprocmask, 4, how, CHECK_SIGSET_NULL_OK (set),
  66                          CHECK_SIGSET_NULL_OK (oset), _NSIG / 8);
  67 #else
  68 # ifdef __NR_rt_sigprocmask
  69   /* First try the RT signals.  */
  70   if (!__libc_missing_rt_sigs)
  71     {
  72       /* XXX The size argument hopefully will have to be changed to the
  73          real size of the user-level sigset_t.  */
  74       int saved_errno = errno;
  75       int result = INLINE_SYSCALL (rt_sigprocmask, 4, how,
  76                                    CHECK_SIGSET_NULL_OK (set),
  77                                    CHECK_SIGSET_NULL_OK (oset), _NSIG / 8);
  78
  79       if (result >= 0 || errno != ENOSYS)
  80         return result;
  81
  82       __set_errno (saved_errno);
  83       __libc_missing_rt_sigs = 1;
  84     }
  85 # endif
  86
  87   return INLINE_SYSCALL (sigprocmask, 3, how, CHECK_SIGSET_NULL_OK (set),
  88                          CHECK_SIGSET_NULL_OK (oset));
  89 #endif
  90 }
  91 weak_alias (__sigprocmask, sigprocmask)