| /* POSIX.1 `sigaction' call for Linux/i386. |
| Copyright (C) 1991-2014 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <sysdep.h> |
| #include <errno.h> |
| #include <stddef.h> |
| #include <signal.h> |
| #include <string.h> |
| |
| #include <sysdep.h> |
| #include <sys/syscall.h> |
| #include <ldsodefs.h> |
| |
| #include <kernel-features.h> |
| |
| /* The difference here is that the sigaction structure used in the |
| kernel is not the same as we use in the libc. Therefore we must |
| translate it here. */ |
| #include <kernel_sigaction.h> |
| |
| /* We do not globally define the SA_RESTORER flag so do it here. */ |
| #define SA_RESTORER 0x04000000 |
| |
| |
| /* Using the hidden attribute here does not change the code but it |
| helps to avoid warnings. */ |
| #ifdef __NR_rt_sigaction |
| extern void restore_rt (void) asm ("__restore_rt") attribute_hidden; |
| #endif |
| extern void restore (void) asm ("__restore") attribute_hidden; |
| |
| |
| /* If ACT is not NULL, change the action for SIG to *ACT. |
| If OACT is not NULL, put the old action for SIG in *OACT. */ |
| int |
| __libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact) |
| { |
| int result; |
| |
| struct kernel_sigaction kact, koact; |
| |
| if (act) |
| { |
| kact.k_sa_handler = act->sa_handler; |
| kact.sa_flags = act->sa_flags; |
| memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t)); |
| |
| if (GLRO(dl_sysinfo_dso) == NULL) |
| { |
| kact.sa_flags |= SA_RESTORER; |
| |
| kact.sa_restorer = ((act->sa_flags & SA_SIGINFO) |
| ? &restore_rt : &restore); |
| } |
| } |
| |
| /* XXX The size argument hopefully will have to be changed to the |
| real size of the user-level sigset_t. */ |
| result = INLINE_SYSCALL (rt_sigaction, 4, |
| sig, act ? &kact : NULL, |
| oact ? &koact : NULL, _NSIG / 8); |
| |
| if (oact && result >= 0) |
| { |
| oact->sa_handler = koact.k_sa_handler; |
| memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t)); |
| oact->sa_flags = koact.sa_flags; |
| oact->sa_restorer = koact.sa_restorer; |
| } |
| return result; |
| } |
| libc_hidden_def (__libc_sigaction) |
| |
| #ifdef WRAPPER_INCLUDE |
| # include WRAPPER_INCLUDE |
| #endif |
| |
| #ifndef LIBC_SIGACTION |
| weak_alias (__libc_sigaction, __sigaction) |
| libc_hidden_weak (__sigaction) |
| weak_alias (__libc_sigaction, sigaction) |
| #endif |
| |
| /* NOTE: Please think twice before making any changes to the bits of |
| code below. GDB needs some intimate knowledge about it to |
| recognize them as signal trampolines, and make backtraces through |
| signal handlers work right. Important are both the names |
| (__restore and __restore_rt) and the exact instruction sequence. |
| If you ever feel the need to make any changes, please notify the |
| appropriate GDB maintainer. */ |
| |
| #define RESTORE(name, syscall) RESTORE2 (name, syscall) |
| #define RESTORE2(name, syscall) \ |
| asm \ |
| ( \ |
| ".text\n" \ |
| " .align 16\n" \ |
| "__" #name ":\n" \ |
| " movl $" #syscall ", %eax\n" \ |
| " int $0x80" \ |
| ); |
| |
| #ifdef __NR_rt_sigaction |
| /* The return code for realtime-signals. */ |
| RESTORE (restore_rt, __NR_rt_sigreturn) |
| #endif |
| |
| /* For the boring old signals. */ |
| #undef RESTORE2 |
| #define RESTORE2(name, syscall) \ |
| asm \ |
| ( \ |
| ".text\n" \ |
| " .align 8\n" \ |
| "__" #name ":\n" \ |
| " popl %eax\n" \ |
| " movl $" #syscall ", %eax\n" \ |
| " int $0x80" \ |
| ); |
| |
| RESTORE (restore, __NR_sigreturn) |