sysdeps/unix/sysv/linux/sigaction.c

   1 /* Copyright (C) 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 <string.h>
  22
  23 #include <sysdep.h>
  24 #include <sys/syscall.h>
  25
  26 /* The difference here is that the sigaction structure used in the
  27    kernel is not the same as we use in the libc.  Therefore we must
  28    translate it here.  */
  29 #include <kernel_sigaction.h>
  30
  31 extern int __syscall_sigaction (int, const struct old_kernel_sigaction *,
  32                                 struct old_kernel_sigaction *);
  33 extern int __syscall_rt_sigaction (int, const struct kernel_sigaction *,
  34                                    struct kernel_sigaction *, size_t);
  35
  36 /* The variable is shared between all wrappers around signal handling
  37    functions which have RT equivalents.  */
  38 int __libc_missing_rt_sigs;
  39
  40
  41 /* If ACT is not NULL, change the action for SIG to *ACT.
  42    If OACT is not NULL, put the old action for SIG in *OACT.  */
  43 int
  44 __sigaction (sig, act, oact)
  45      int sig;
  46      const struct sigaction *act;
  47      struct sigaction *oact;
  48 {
  49   struct old_kernel_sigaction k_sigact, k_osigact;
  50   int result;
  51
  52 #ifdef __NR_rt_sigaction
  53   /* First try the RT signals.  */
  54   if (!__libc_missing_rt_sigs)
  55     {
  56       struct kernel_sigaction kact, koact;
  57       int saved_errno = errno;
  58
  59       if (act)
  60         {
  61           kact.k_sa_handler = act->sa_handler;
  62           memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
  63           kact.sa_flags = act->sa_flags;
  64 # ifdef HAVE_SA_RESTORER
  65           kact.sa_restorer = act->sa_restorer;
  66 # endif
  67         }
  68
  69       /* XXX The size argument hopefully will have to be changed to the
  70          real size of the user-level sigset_t.  */
  71       result = INLINE_SYSCALL (rt_sigaction, 4, sig, act ? &kact : NULL,
  72                                oact ? &koact : NULL, _NSIG / 8);
  73
  74       if (result >= 0 || errno != ENOSYS)
  75         {
  76           if (oact && result >= 0)
  77             {
  78               oact->sa_handler = koact.k_sa_handler;
  79               memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
  80               oact->sa_flags = koact.sa_flags;
  81 # ifdef HAVE_SA_RESTORER
  82               oact->sa_restorer = koact.sa_restorer;
  83 # endif
  84             }
  85           return result;
  86         }
  87
  88       __set_errno (saved_errno);
  89       __libc_missing_rt_sigs = 1;
  90     }
  91 #endif
  92
  93   if (act)
  94     {
  95       k_sigact.k_sa_handler = act->sa_handler;
  96       k_sigact.sa_mask = act->sa_mask.__val[0];
  97       k_sigact.sa_flags = act->sa_flags;
  98 #ifdef HAVE_SA_RESTORER
  99       k_sigact.sa_restorer = act->sa_restorer;
 100 #endif
 101     }
 102   result = INLINE_SYSCALL (sigaction, 3, sig, act ? &k_sigact : NULL,
 103                            oact ? &k_osigact : NULL);
 104   if (oact && result >= 0)
 105     {
 106       oact->sa_handler = k_osigact.k_sa_handler;
 107       oact->sa_mask.__val[0] = k_osigact.sa_mask;
 108       oact->sa_flags = k_osigact.sa_flags;
 109 #ifdef HAVE_SA_RESTORER
 110       oact->sa_restorer = k_osigact.sa_restorer;
 111 #endif
 112     }
 113   return result;
 114 }
 115
 116 weak_alias (__sigaction, sigaction)