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

   1 /* Copyright (C) 1997,1998,1999,2000,2002,2003, 2004
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <sgidefs.h>
  22 #include <signal.h>
  23 #include <string.h>
  24
  25 #include <sysdep.h>
  26 #include <sys/syscall.h>
  27
  28 #include <sgidefs.h>
  29
  30 #include "kernel-features.h"
  31
  32 /* The difference here is that the sigaction structure used in the
  33    kernel is not the same as we use in the libc.  Therefore we must
  34    translate it here.  */
  35 #include <kernel_sigaction.h>
  36
  37 #if __ASSUME_REALTIME_SIGNALS == 0
  38 /* The variable is shared between all wrappers around signal handling
  39    functions which have RT equivalents.  This is the definition.  */
  40 int __libc_missing_rt_sigs;
  41
  42 #endif
  43
  44 #if _MIPS_SIM != _ABIO32
  45
  46 # ifdef __NR_rt_sigreturn
  47 static void restore_rt (void) asm ("__restore_rt");
  48 # endif
  49 # ifdef __NR_sigreturn
  50 static void restore (void) asm ("__restore");
  51 # endif
  52 #endif
  53
  54 /* If ACT is not NULL, change the action for SIG to *ACT.
  55    If OACT is not NULL, put the old action for SIG in *OACT.  */
  56 int
  57 __libc_sigaction (sig, act, oact)
  58      int sig;
  59      const struct sigaction *act;
  60      struct sigaction *oact;
  61 {
  62 #if __ASSUME_REALTIME_SIGNALS == 0
  63   struct old_kernel_sigaction k_sigact, k_osigact;
  64 #endif
  65   int result;
  66
  67 #if defined __NR_rt_sigaction || __ASSUME_REALTIME_SIGNALS > 0
  68   /* First try the RT signals.  */
  69 # if __ASSUME_REALTIME_SIGNALS == 0
  70   if (!__libc_missing_rt_sigs)
  71 # endif
  72     {
  73       struct kernel_sigaction kact, koact;
  74       /* Save the current error value for later.  We need not do this
  75          if we are guaranteed to have realtime signals.  */
  76 # if __ASSUME_REALTIME_SIGNALS == 0
  77       int saved_errno = errno;
  78 # endif
  79
  80       if (act)
  81         {
  82           kact.k_sa_handler = act->sa_handler;
  83           memcpy (&kact.sa_mask, &act->sa_mask, sizeof (kernel_sigset_t));
  84           kact.sa_flags = act->sa_flags;
  85 # ifdef HAVE_SA_RESTORER
  86 #  if _MIPS_SIM == _ABIO32
  87           kact.sa_restorer = act->sa_restorer;
  88 #  else
  89           kact.sa_restorer = &restore_rt;
  90 #  endif
  91 # endif
  92         }
  93
  94       /* XXX The size argument hopefully will have to be changed to the
  95          real size of the user-level sigset_t.  */
  96       result = INLINE_SYSCALL (rt_sigaction, 4, sig,
  97                                act ? __ptrvalue (&kact) : NULL,
  98                                oact ? __ptrvalue (&koact) : NULL,
  99                                sizeof (kernel_sigset_t));
 100
 101 # if __ASSUME_REALTIME_SIGNALS == 0
 102       if (result >= 0 || errno != ENOSYS)
 103 # endif
 104         {
 105           if (oact && result >= 0)
 106             {
 107               oact->sa_handler = koact.k_sa_handler;
 108               memcpy (&oact->sa_mask, &koact.sa_mask,
 109                                 sizeof (kernel_sigset_t));
 110               oact->sa_flags = koact.sa_flags;
 111 # ifdef HAVE_SA_RESTORER
 112               oact->sa_restorer = koact.sa_restorer;
 113 # endif
 114             }
 115           return result;
 116         }
 117
 118 # if __ASSUME_REALTIME_SIGNALS == 0
 119       __set_errno (saved_errno);
 120       __libc_missing_rt_sigs = 1;
 121 # endif
 122     }
 123 #endif
 124
 125 #if __ASSUME_REALTIME_SIGNALS == 0
 126   if (act)
 127     {
 128       k_sigact.k_sa_handler = act->sa_handler;
 129       k_sigact.sa_mask = act->sa_mask.__val[0];
 130       k_sigact.sa_flags = act->sa_flags;
 131 # ifdef HAVE_SA_RESTORER
 132       k_sigact.sa_restorer = act->sa_restorer;
 133 # endif
 134     }
 135   result = INLINE_SYSCALL (sigaction, 3, sig,
 136                            act ? __ptrvalue (&k_sigact) : NULL,
 137                            oact ? __ptrvalue (&k_osigact) : NULL);
 138   if (oact && result >= 0)
 139     {
 140       oact->sa_handler = k_osigact.k_sa_handler;
 141       oact->sa_mask.__val[0] = k_osigact.sa_mask;
 142       oact->sa_flags = k_osigact.sa_flags;
 143 # ifdef HAVE_SA_RESTORER
 144 #  if _MIPS_SIM == _ABIO32
 145       oact->sa_restorer = k_osigact.sa_restorer;
 146 #  else
 147       oact->sa_restorer = &restore;
 148 #  endif
 149 # endif
 150     }
 151   return result;
 152 #endif
 153 }
 154 libc_hidden_def (__libc_sigaction)
 155
 156 #ifndef LIBC_SIGACTION
 157 weak_alias (__libc_sigaction, __sigaction)
 158 libc_hidden_weak (__sigaction)
 159 weak_alias (__libc_sigaction, sigaction)
 160 #endif
 161
 162 /* NOTE: Please think twice before making any changes to the bits of
 163    code below.  GDB needs some intimate knowledge about it to
 164    recognize them as signal trampolines, and make backtraces through
 165    signal handlers work right.  Important are both the names
 166    (__restore_rt) and the exact instruction sequence.
 167    If you ever feel the need to make any changes, please notify the
 168    appropriate GDB maintainer.  */
 169
 170 #define RESTORE(name, syscall) RESTORE2 (name, syscall)
 171 #define RESTORE2(name, syscall) \
 172 asm                                             \
 173   (                                             \
 174    ".align 4\n"                                 \
 175    "__" #name ":\n"                             \
 176    "    li $2, " #syscall "\n"                  \
 177    "    syscall\n"                              \
 178    );
 179
 180 /* The return code for realtime-signals.  */
 181 #if _MIPS_SIM != _ABIO32
 182 # ifdef __NR_rt_sigreturn
 183 RESTORE (restore_rt, __NR_rt_sigreturn)
 184 # endif
 185 # ifdef __NR_sigreturn
 186 RESTORE (restore, __NR_sigreturn)
 187 # endif
 188 #endif