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187 lines
6.9 KiB
C
187 lines
6.9 KiB
C
/* POSIX.1 `sigaction' call for Linux/x86-64.
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Copyright (C) 2001, 2002, 2003, 2005, 2006 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, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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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 <kernel-features.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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#include "ucontext_i.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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extern void restore_rt (void) asm ("__restore_rt") 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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memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
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kact.sa_flags = act->sa_flags | SA_RESTORER;
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kact.sa_restorer = &restore_rt;
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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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result = INLINE_SYSCALL (rt_sigaction, 4,
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sig, act ? __ptrvalue (&kact) : NULL,
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oact ? __ptrvalue (&koact) : NULL, _NSIG / 8);
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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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#ifdef WRAPPER_INCLUDE
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# include WRAPPER_INCLUDE
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#endif
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#ifndef LIBC_SIGACTION
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weak_alias (__libc_sigaction, __sigaction)
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libc_hidden_weak (__sigaction)
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weak_alias (__libc_sigaction, sigaction)
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#endif
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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_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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The unwind information starts a byte before __restore_rt, so that
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it is found when unwinding, to get an address the unwinder assumes
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will be in the middle of a call instruction. See the Linux kernel
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(the i386 vsyscall, in particular) for an explanation of the complex
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unwind information used here in order to get the traditional CFA.
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We do not restore cs - it's only stored as two bytes here so that's
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a bit tricky. We don't use the gas cfi directives, so that we can
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reliably add .cfi_signal_frame. */
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#define do_cfa_expr \
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" .byte 0x0f\n" /* DW_CFA_def_cfa_expression */ \
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" .uleb128 2f-1f\n" /* length */ \
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"1: .byte 0x77\n" /* DW_OP_breg7 */ \
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" .sleb128 " CFI_STRINGIFY (oRSP) "\n" \
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" .byte 0x06\n" /* DW_OP_deref */ \
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"2:"
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#define do_expr(regno, offset) \
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" .byte 0x10\n" /* DW_CFA_expression */ \
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" .uleb128 " CFI_STRINGIFY (regno) "\n" \
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" .uleb128 2f-1f\n" /* length */ \
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"1: .byte 0x77\n" /* DW_OP_breg7 */ \
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" .sleb128 " CFI_STRINGIFY (offset) "\n" \
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"2:"
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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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/* `nop' for debuggers assuming `call' should not disalign the code. */ \
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" nop\n" \
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".align 16\n" \
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".LSTART_" #name ":\n" \
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" .type __" #name ",@function\n" \
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"__" #name ":\n" \
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" movq $" #syscall ", %rax\n" \
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" syscall\n" \
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".LEND_" #name ":\n" \
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".section .eh_frame,\"a\",@progbits\n" \
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".LSTARTFRAME_" #name ":\n" \
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" .long .LENDCIE_" #name "-.LSTARTCIE_" #name "\n" \
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".LSTARTCIE_" #name ":\n" \
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" .long 0\n" /* CIE ID */ \
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" .byte 1\n" /* Version number */ \
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" .string \"zRS\"\n" /* NUL-terminated augmentation string */ \
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" .uleb128 1\n" /* Code alignment factor */ \
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" .sleb128 -8\n" /* Data alignment factor */ \
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" .uleb128 16\n" /* Return address register column (rip) */ \
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/* Augmentation value length */ \
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" .uleb128 .LENDAUGMNT_" #name "-.LSTARTAUGMNT_" #name "\n" \
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".LSTARTAUGMNT_" #name ":\n" \
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" .byte 0x1b\n" /* DW_EH_PE_pcrel|DW_EH_PE_sdata4. */ \
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".LENDAUGMNT_" #name ":\n" \
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" .align 8\n" \
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".LENDCIE_" #name ":\n" \
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" .long .LENDFDE_" #name "-.LSTARTFDE_" #name "\n" /* FDE len */ \
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".LSTARTFDE_" #name ":\n" \
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" .long .LSTARTFDE_" #name "-.LSTARTFRAME_" #name "\n" /* CIE */ \
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/* `LSTART_' is subtracted 1 as debuggers assume a `call' here. */ \
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" .long (.LSTART_" #name "-1)-.\n" /* PC-relative start addr. */ \
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" .long .LEND_" #name "-(.LSTART_" #name "-1)\n" \
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" .uleb128 0\n" /* FDE augmentation length */ \
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do_cfa_expr \
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do_expr (8 /* r8 */, oR8) \
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do_expr (9 /* r9 */, oR9) \
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do_expr (10 /* r10 */, oR10) \
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do_expr (11 /* r11 */, oR11) \
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do_expr (12 /* r12 */, oR12) \
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do_expr (13 /* r13 */, oR13) \
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do_expr (14 /* r14 */, oR14) \
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do_expr (15 /* r15 */, oR15) \
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do_expr (5 /* rdi */, oRDI) \
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do_expr (4 /* rsi */, oRSI) \
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do_expr (6 /* rbp */, oRBP) \
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do_expr (3 /* rbx */, oRBX) \
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do_expr (1 /* rdx */, oRDX) \
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do_expr (0 /* rax */, oRAX) \
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do_expr (2 /* rcx */, oRCX) \
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do_expr (7 /* rsp */, oRSP) \
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do_expr (16 /* rip */, oRIP) \
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/* libgcc-4.1.1 has only `DWARF_FRAME_REGISTERS == 17'. */ \
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/* do_expr (49 |* rflags *|, oEFL) */ \
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/* `cs'/`ds'/`fs' are unaligned and a different size. */ \
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/* gas: Error: register save offset not a multiple of 8 */ \
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" .align 8\n" \
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".LENDFDE_" #name ":\n" \
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" .previous\n" \
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);
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/* The return code for realtime-signals. */
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RESTORE (restore_rt, __NR_rt_sigreturn)
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