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130 lines
3.9 KiB
C
130 lines
3.9 KiB
C
/* POSIX.1 `sigaction' call for Linux/i386.
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Copyright (C) 1991-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#include <errno.h>
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#include <stddef.h>
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#include <signal.h>
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#include <string.h>
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#include <sysdep.h>
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#include <sys/syscall.h>
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#include <ldsodefs.h>
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/* The difference here is that the sigaction structure used in the
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kernel is not the same as we use in the libc. Therefore we must
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translate it here. */
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#include <kernel_sigaction.h>
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/* We do not globally define the SA_RESTORER flag so do it here. */
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#define SA_RESTORER 0x04000000
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/* Using the hidden attribute here does not change the code but it
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helps to avoid warnings. */
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#ifdef __NR_rt_sigaction
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extern void restore_rt (void) asm ("__restore_rt") attribute_hidden;
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#endif
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extern void restore (void) asm ("__restore") attribute_hidden;
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/* If ACT is not NULL, change the action for SIG to *ACT.
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If OACT is not NULL, put the old action for SIG in *OACT. */
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int
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__libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
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{
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int result;
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struct kernel_sigaction kact, koact;
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if (act)
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{
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kact.k_sa_handler = act->sa_handler;
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kact.sa_flags = act->sa_flags;
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memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
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if (GLRO(dl_sysinfo_dso) == NULL)
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{
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kact.sa_flags |= SA_RESTORER;
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kact.sa_restorer = ((act->sa_flags & SA_SIGINFO)
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? &restore_rt : &restore);
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}
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}
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/* XXX The size argument hopefully will have to be changed to the
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real size of the user-level sigset_t. */
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INTERNAL_SYSCALL_DECL (err);
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result = INTERNAL_SYSCALL (rt_sigaction, err, 4,
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sig, act ? &kact : NULL,
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oact ? &koact : NULL, _NSIG / 8);
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if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result, err)))
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return INLINE_SYSCALL_ERROR_RETURN_VALUE (INTERNAL_SYSCALL_ERRNO (result,
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err));
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else if (oact && result >= 0)
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{
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oact->sa_handler = koact.k_sa_handler;
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memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
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oact->sa_flags = koact.sa_flags;
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oact->sa_restorer = koact.sa_restorer;
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}
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return result;
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}
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libc_hidden_def (__libc_sigaction)
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#include <nptl/sigaction.c>
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/* NOTE: Please think twice before making any changes to the bits of
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code below. GDB needs some intimate knowledge about it to
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recognize them as signal trampolines, and make backtraces through
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signal handlers work right. Important are both the names
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(__restore and __restore_rt) and the exact instruction sequence.
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If you ever feel the need to make any changes, please notify the
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appropriate GDB maintainer. */
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#define RESTORE(name, syscall) RESTORE2 (name, syscall)
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#define RESTORE2(name, syscall) \
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asm \
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( \
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".text\n" \
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" .align 16\n" \
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"__" #name ":\n" \
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" movl $" #syscall ", %eax\n" \
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" int $0x80" \
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);
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#ifdef __NR_rt_sigaction
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/* The return code for realtime-signals. */
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RESTORE (restore_rt, __NR_rt_sigreturn)
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#endif
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/* For the boring old signals. */
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#undef RESTORE2
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#define RESTORE2(name, syscall) \
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asm \
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( \
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".text\n" \
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" .align 8\n" \
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"__" #name ":\n" \
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" popl %eax\n" \
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" movl $" #syscall ", %eax\n" \
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" int $0x80" \
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);
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RESTORE (restore, __NR_sigreturn)
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