sysdeps/unix/sysv/linux/i386/sigaction.c

   1 /* POSIX.1 `sigaction' call for Linux/i386.
   2    Copyright (C) 1991, 1995, 1996, 1997 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 Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    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    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <sysdep.h>
  21 #include <errno.h>
  22 #include <stddef.h>
  23 #include <signal.h>
  24
  25 /* The difference here is that the sigaction structure used in the
  26    kernel is not the same as we use in the libc.  Therefore we must
  27    translate it here.  */
  28 #include <kernel_sigaction.h>
  29
  30
  31 /* If ACT is not NULL, change the action for SIG to *ACT.
  32    If OACT is not NULL, put the old action for SIG in *OACT.  */
  33 int
  34 __sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
  35 {
  36   struct kernel_sigaction k_newact, k_oldact;
  37   int result;
  38
  39   if (act)
  40     {
  41       k_newact.sa_handler = act->sa_handler;
  42       k_newact.sa_mask = act->sa_mask.__val[0];
  43       k_newact.sa_flags = act->sa_flags;
  44
  45       k_newact.sa_restorer = ((act->sa_flags & SA_NOMASK)
  46                               ? &&restore_nomask : &&restore);
  47     }
  48
  49   asm volatile ("pushl %%ebx\n"
  50                 "movl %2, %%ebx\n"
  51                 "int $0x80\n"
  52                 "popl %%ebx"
  53                 : "=a" (result)
  54                 : "0" (SYS_ify (sigaction)), "r" (sig),
  55                   "c" (act ? &k_newact : 0), "d" (oact ? &k_oldact : 0));
  56
  57   if (result < 0)
  58     {
  59       __set_errno (-result);
  60       return -1;
  61     }
  62
  63   if (oact)
  64     {
  65       oact->sa_handler = k_oldact.sa_handler;
  66       oact->sa_mask.__val[0] = k_oldact.sa_mask;
  67       oact->sa_flags = k_oldact.sa_flags;
  68       oact->sa_restorer = k_oldact.sa_restorer;
  69     }
  70
  71   return 0;
  72
  73  restore:
  74   asm (
  75 #ifdef  PIC
  76        "        pushl %%ebx\n"
  77        "        call 0f\n"
  78        "0:      popl %%ebx\n"
  79        "        addl $_GLOBAL_OFFSET_TABLE_+[.-0b], %%ebx\n"
  80        "        addl $8, %%esp\n"
  81        "        call __sigsetmask@PLT\n"
  82        "        addl $8, %%esp\n"
  83        "        popl %%ebx\n"
  84 #else
  85        "        addl $4, %%esp\n"
  86        "        call __sigsetmask\n"
  87        "        addl $4, %%esp\n"
  88 #endif
  89        "        popl %%eax\n"
  90        "        popl %%ecx\n"
  91        "        popl %%edx\n"
  92        "        popf\n"
  93        "        ret"
  94        : : );
  95
  96  restore_nomask:
  97   asm ("        addl $4, %%esp\n"
  98        "        popl %%eax\n"
  99        "        popl %%ecx\n"
 100        "        popl %%edx\n"
 101        "        popf\n"
 102        "        ret"
 103        : : );
 104
 105   /* NOTREACHED */
 106   return -1;
 107 }
 108
 109 weak_alias (__sigaction, sigaction)