sysdeps/unix/sysv/linux/sigaction.c

   1 /* Copyright (C) 1997 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
  22 /* The difference here is that the sigaction structure used in the
  23    kernel is not the same as we use in the libc.  Therefore we must
  24    translate it here.  */
  25 #include <kernel_sigaction.h>
  26
  27 extern int __syscall_sigaction (int, const struct old_kernel_sigaction *,
  28                                 struct old_kernel_sigaction *);
  29 extern int __syscall_rt_sigaction (int, const struct sigaction *,
  30                                    struct sigaction *, size_t);
  31
  32 /* The variable is shared between all wrappers around signal handling
  33    functions which have RT equivalents.  It is defined in sigsuspend.c.  */
  34 extern int __libc_have_rt_sigs;
  35
  36
  37 /* If ACT is not NULL, change the action for SIG to *ACT.
  38    If OACT is not NULL, put the old action for SIG in *OACT.  */
  39 int
  40 __sigaction (sig, act, oact)
  41      int sig;
  42      const struct sigaction *act;
  43      struct sigaction *oact;
  44 {
  45   struct old_kernel_sigaction k_sigact, k_osigact;
  46   int error;
  47
  48   /* First try the RT signals.  */
  49   if (__libc_have_rt_sigs)
  50     {
  51       /* XXX The size argument hopefully will have to be changed to the
  52          real size of the user-level sigset_t.  */
  53       int result = __syscall_rt_sigaction (sig, act, oact, _NSIG / 8);
  54
  55       if (result >= 0 || errno != ENOSYS)
  56         return result;
  57
  58       __libc_have_rt_sigs = 0;
  59     }
  60
  61   if (act)
  62     {
  63       k_sigact.k_sa_handler = act->sa_handler;
  64       k_sigact.sa_mask = act->sa_mask.__val[0];
  65       k_sigact.sa_flags = act->sa_flags;
  66 #ifdef HAVE_SA_RESTORER
  67       k_sigact.sa_restorer = act->sa_restorer;
  68 #endif
  69     }
  70   error = __syscall_sigaction (sig, act ? &k_sigact : 0,
  71                                oact ? &k_osigact : 0);
  72   if (oact && error >= 0)
  73     {
  74       oact->sa_handler = k_osigact.k_sa_handler;
  75       oact->sa_mask.__val[0] = k_osigact.sa_mask;
  76       oact->sa_flags = k_osigact.sa_flags;
  77 #ifdef HAVE_SA_RESTORER
  78       oact->sa_restorer = k_osigact.sa_restorer;
  79 #endif
  80     }
  81   return error;
  82 }
  83
  84 weak_alias (__sigaction, sigaction)