sysdeps/unix/sysv/linux/mips/sigaction.c

   1 /* Copyright (C) 1997-2012 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 <sgidefs.h>
  20 #include <signal.h>
  21 #include <string.h>
  22
  23 #include <sysdep.h>
  24 #include <sys/syscall.h>
  25
  26 #include <sgidefs.h>
  27
  28 #include <kernel-features.h>
  29
  30 /* The difference here is that the sigaction structure used in the
  31    kernel is not the same as we use in the libc.  Therefore we must
  32    translate it here.  */
  33 #include <kernel_sigaction.h>
  34
  35 #if _MIPS_SIM != _ABIO32
  36
  37 # ifdef __NR_rt_sigreturn
  38 static void restore_rt (void) asm ("__restore_rt");
  39 # endif
  40 # ifdef __NR_sigreturn
  41 static void restore (void) asm ("__restore");
  42 # endif
  43 #endif
  44
  45 /* If ACT is not NULL, change the action for SIG to *ACT.
  46    If OACT is not NULL, put the old action for SIG in *OACT.  */
  47 int
  48 __libc_sigaction (sig, act, oact)
  49      int sig;
  50      const struct sigaction *act;
  51      struct sigaction *oact;
  52 {
  53   int result;
  54
  55   struct kernel_sigaction kact, koact;
  56
  57   if (act)
  58     {
  59       kact.k_sa_handler = act->sa_handler;
  60       memcpy (&kact.sa_mask, &act->sa_mask, sizeof (kernel_sigset_t));
  61       kact.sa_flags = act->sa_flags;
  62 #ifdef HAVE_SA_RESTORER
  63 # if _MIPS_SIM == _ABIO32
  64       kact.sa_restorer = act->sa_restorer;
  65 # else
  66       kact.sa_restorer = &restore_rt;
  67 # endif
  68 #endif
  69     }
  70
  71   /* XXX The size argument hopefully will have to be changed to the
  72      real size of the user-level sigset_t.      */
  73   result = INLINE_SYSCALL (rt_sigaction, 4, sig,
  74                            act ? __ptrvalue (&kact) : NULL,
  75                            oact ? __ptrvalue (&koact) : NULL,
  76                            sizeof (kernel_sigset_t));
  77
  78   if (oact && result >= 0)
  79     {
  80       oact->sa_handler = koact.k_sa_handler;
  81       memcpy (&oact->sa_mask, &koact.sa_mask,
  82               sizeof (kernel_sigset_t));
  83       oact->sa_flags = koact.sa_flags;
  84 #ifdef HAVE_SA_RESTORER
  85       oact->sa_restorer = koact.sa_restorer;
  86 #endif
  87     }
  88   return result;
  89 }
  90 libc_hidden_def (__libc_sigaction)
  91
  92 #ifdef WRAPPER_INCLUDE
  93 # include WRAPPER_INCLUDE
  94 #endif
  95
  96 #ifndef LIBC_SIGACTION
  97 weak_alias (__libc_sigaction, __sigaction)
  98 libc_hidden_weak (__sigaction)
  99 weak_alias (__libc_sigaction, sigaction)
 100 #endif
 101
 102 /* NOTE: Please think twice before making any changes to the bits of
 103    code below.  GDB needs some intimate knowledge about it to
 104    recognize them as signal trampolines, and make backtraces through
 105    signal handlers work right.  Important are both the names
 106    (__restore_rt) and the exact instruction sequence.
 107    If you ever feel the need to make any changes, please notify the
 108    appropriate GDB maintainer.  */
 109
 110 #define RESTORE(name, syscall) RESTORE2 (name, syscall)
 111 #define RESTORE2(name, syscall) \
 112 asm                                             \
 113   (                                             \
 114    ".align 4\n"                                 \
 115    "__" #name ":\n"                             \
 116    "    li $2, " #syscall "\n"                  \
 117    "    syscall\n"                              \
 118    );
 119
 120 /* The return code for realtime-signals.  */
 121 #if _MIPS_SIM != _ABIO32
 122 # ifdef __NR_rt_sigreturn
 123 RESTORE (restore_rt, __NR_rt_sigreturn)
 124 # endif
 125 # ifdef __NR_sigreturn
 126 RESTORE (restore, __NR_sigreturn)
 127 # endif
 128 #endif