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

   1 /* Copyright (C) 1997-2018 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 /* The difference here is that the sigaction structure used in the
  29    kernel is not the same as we use in the libc.  Therefore we must
  30    translate it here.  */
  31 #include <kernel_sigaction.h>
  32
  33 #if _MIPS_SIM != _ABIO32
  34
  35 # ifdef __NR_rt_sigreturn
  36 static void restore_rt (void) asm ("__restore_rt");
  37 # endif
  38 # ifdef __NR_sigreturn
  39 static void restore (void) asm ("__restore");
  40 # endif
  41 #endif
  42
  43 /* If ACT is not NULL, change the action for SIG to *ACT.
  44    If OACT is not NULL, put the old action for SIG in *OACT.  */
  45 int
  46 __libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
  47 {
  48   int result;
  49
  50   struct kernel_sigaction kact, koact;
  51
  52   if (act)
  53     {
  54       kact.k_sa_handler = act->sa_handler;
  55       memcpy (&kact.sa_mask, &act->sa_mask, sizeof (kernel_sigset_t));
  56       kact.sa_flags = act->sa_flags;
  57 #ifdef HAVE_SA_RESTORER
  58 # if _MIPS_SIM == _ABIO32
  59       kact.sa_restorer = act->sa_restorer;
  60 # else
  61       kact.sa_restorer = &restore_rt;
  62 # endif
  63 #endif
  64     }
  65
  66   /* XXX The size argument hopefully will have to be changed to the
  67      real size of the user-level sigset_t.      */
  68   result = INLINE_SYSCALL (rt_sigaction, 4, sig,
  69                            act ? &kact : NULL,
  70                            oact ? &koact : NULL,
  71                            sizeof (kernel_sigset_t));
  72
  73   if (oact && result >= 0)
  74     {
  75       oact->sa_handler = koact.k_sa_handler;
  76       memcpy (&oact->sa_mask, &koact.sa_mask,
  77               sizeof (kernel_sigset_t));
  78       oact->sa_flags = koact.sa_flags;
  79 #ifdef HAVE_SA_RESTORER
  80       oact->sa_restorer = koact.sa_restorer;
  81 #endif
  82     }
  83   return result;
  84 }
  85 libc_hidden_def (__libc_sigaction)
  86
  87 #include <nptl/sigaction.c>
  88
  89
  90 /* NOTE: Please think twice before making any changes to the bits of
  91    code below.  GDB needs some intimate knowledge about it to
  92    recognize them as signal trampolines, and make backtraces through
  93    signal handlers work right.  Important are both the names
  94    (__restore_rt) and the exact instruction sequence.
  95    If you ever feel the need to make any changes, please notify the
  96    appropriate GDB maintainer.  */
  97
  98 #define RESTORE(name, syscall) RESTORE2 (name, syscall)
  99 #define RESTORE2(name, syscall) \
 100 asm                                             \
 101   (                                             \
 102    ".align 4\n"                                 \
 103    "__" #name ":\n"                             \
 104    "    li $2, " #syscall "\n"                  \
 105    "    syscall\n"                              \
 106    );
 107
 108 /* The return code for realtime-signals.  */
 109 #if _MIPS_SIM != _ABIO32
 110 # ifdef __NR_rt_sigreturn
 111 RESTORE (restore_rt, __NR_rt_sigreturn)
 112 # endif
 113 # ifdef __NR_sigreturn
 114 RESTORE (restore, __NR_sigreturn)
 115 # endif
 116 #endif