2b356e689c
When the application sets SA_SIGINFO, the signal trampoline parameters are different to follow POSIX. libgcc/ * config/i386/gnu-unwind.h (x86_gnu_fallback_frame_state): Add the posix siginfo case to struct handler_args. Detect between legacy and siginfo from the second parameter, which is a small sigcode in the legacy case, and a pointer in the siginfo case.
142 lines
5.0 KiB
C
142 lines
5.0 KiB
C
/* DWARF2 EH unwinding support for GNU Hurd: x86.
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Copyright (C) 2020-2021 Free Software Foundation, Inc.
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Contributed by Samuel Thibault <samuel.thibault@gnu.org>
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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GCC 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
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GNU General Public License for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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/* Do code reading to identify a signal frame, and set the frame
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state data appropriately. See unwind-dw2.c for the structs. */
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#ifndef inhibit_libc
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#include <signal.h>
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#define MD_FALLBACK_FRAME_STATE_FOR x86_gnu_fallback_frame_state
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static _Unwind_Reason_Code
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x86_gnu_fallback_frame_state
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(struct _Unwind_Context *context, _Unwind_FrameState *fs)
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{
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struct handler_args {
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int signo;
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union
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{
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struct
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{
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long int sigcode;
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struct sigcontext *scp;
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} legacy;
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struct
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{
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siginfo_t *siginfop;
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ucontext_t *uctxp;
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} posix;
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};
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} *handler_args;
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long int sigcode;
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unsigned long usp;
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/*
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* i386 sigtramp frame we are looking for follows.
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* (see glibc/sysdeps/mach/hurd/i386/trampoline.c assembly)
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*
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* rpc_wait_trampoline:
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* 0: b8 e7 ff ff ff mov $-25,%eax mach_msg_trap
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* 5: 9a 00 00 00 00 07 00 lcall $7,$0
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* 12: 89 01 movl %eax, (%ecx)
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* 14: 89 dc movl %ebx, %esp switch to signal stack
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*
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* trampoline:
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* 16: ff d2 call *%edx call the handler function
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* RA HERE
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* 18: 83 c4 0c addl $12, %esp pop its args
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* 21: c3 ret return to sigreturn
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*
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* firewall:
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* 22: f4 hlt
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*/
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if (!( *(unsigned int *)(context->ra ) == 0xc30cc483
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&& *(unsigned char *)(context->ra + 4) == 0xf4
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&& *(unsigned int *)(context->ra - 4) == 0xd2ffdc89
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&& *(unsigned int *)(context->ra - 8) == 0x01890007
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&& *(unsigned int *)(context->ra - 12) == 0x00000000
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&& *(unsigned int *)(context->ra - 16) == 0x9affffff
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&& *(unsigned short *)(context->ra - 18) == 0xe7b8))
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return _URC_END_OF_STACK;
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handler_args = context->cfa;
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sigcode = handler_args->legacy.sigcode;
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if (sigcode >= -16 && sigcode < 4096)
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{
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/* This cannot be a SIGINFO pointer, assume legacy. */
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struct sigcontext *scp = handler_args->legacy.scp;
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usp = scp->sc_uesp;
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fs->regs.reg[0].loc.offset = (unsigned long)&scp->sc_eax - usp;
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fs->regs.reg[1].loc.offset = (unsigned long)&scp->sc_ecx - usp;
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fs->regs.reg[2].loc.offset = (unsigned long)&scp->sc_edx - usp;
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fs->regs.reg[3].loc.offset = (unsigned long)&scp->sc_ebx - usp;
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fs->regs.reg[5].loc.offset = (unsigned long)&scp->sc_ebp - usp;
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fs->regs.reg[6].loc.offset = (unsigned long)&scp->sc_esi - usp;
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fs->regs.reg[7].loc.offset = (unsigned long)&scp->sc_edi - usp;
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fs->regs.reg[8].loc.offset = (unsigned long)&scp->sc_eip - usp;
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}
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else
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{
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/* This is not a valid sigcode, assume SIGINFO. */
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ucontext_t *uctxp = handler_args->posix.uctxp;
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gregset_t *gregset = &uctxp->uc_mcontext.gregs;
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usp = (*gregset)[REG_UESP];
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fs->regs.reg[0].loc.offset = (unsigned long)&(*gregset)[REG_EAX] - usp;
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fs->regs.reg[1].loc.offset = (unsigned long)&(*gregset)[REG_ECX] - usp;
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fs->regs.reg[2].loc.offset = (unsigned long)&(*gregset)[REG_EDX] - usp;
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fs->regs.reg[3].loc.offset = (unsigned long)&(*gregset)[REG_EBX] - usp;
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fs->regs.reg[5].loc.offset = (unsigned long)&(*gregset)[REG_EBP] - usp;
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fs->regs.reg[6].loc.offset = (unsigned long)&(*gregset)[REG_ESI] - usp;
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fs->regs.reg[7].loc.offset = (unsigned long)&(*gregset)[REG_EDI] - usp;
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fs->regs.reg[8].loc.offset = (unsigned long)&(*gregset)[REG_EIP] - usp;
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}
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fs->regs.cfa_how = CFA_REG_OFFSET;
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fs->regs.cfa_reg = 4;
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fs->regs.cfa_offset = usp - (unsigned long) context->cfa;
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fs->regs.reg[0].how = REG_SAVED_OFFSET;
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fs->regs.reg[1].how = REG_SAVED_OFFSET;
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fs->regs.reg[2].how = REG_SAVED_OFFSET;
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fs->regs.reg[3].how = REG_SAVED_OFFSET;
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fs->regs.reg[5].how = REG_SAVED_OFFSET;
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fs->regs.reg[6].how = REG_SAVED_OFFSET;
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fs->regs.reg[7].how = REG_SAVED_OFFSET;
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fs->regs.reg[8].how = REG_SAVED_OFFSET;
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fs->retaddr_column = 8;
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fs->signal_frame = 1;
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return _URC_NO_REASON;
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}
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#endif /* ifndef inhibit_libc */
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