2018-04-24 22:26:16 +03:00
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/*
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* Emulation of Linux signals
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*
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* Copyright (c) 2003 Fabrice Bellard
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*
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* This program 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 2 of the License, or
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* (at your option) any later version.
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*
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* This program 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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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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2018-04-24 22:26:28 +03:00
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#include "qemu/osdep.h"
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#include "qemu.h"
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#include "signal-common.h"
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#include "linux-user/trace.h"
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/* Signal handler invocation must be transparent for the code being
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interrupted. Complete CPU (hart) state is saved on entry and restored
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before returning from the handler. Process sigmask is also saved to block
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signals while the handler is running. The handler gets its own stack,
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which also doubles as storage for the CPU state and sigmask.
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The code below is qemu re-implementation of arch/riscv/kernel/signal.c */
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struct target_sigcontext {
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abi_long pc;
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abi_long gpr[31]; /* x0 is not present, so all offsets must be -1 */
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uint64_t fpr[32];
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uint32_t fcsr;
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}; /* cf. riscv-linux:arch/riscv/include/uapi/asm/ptrace.h */
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struct target_ucontext {
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unsigned long uc_flags;
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struct target_ucontext *uc_link;
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target_stack_t uc_stack;
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target_sigset_t uc_sigmask;
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2020-04-12 05:08:30 +03:00
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uint8_t __unused[1024 / 8 - sizeof(target_sigset_t)];
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struct target_sigcontext uc_mcontext QEMU_ALIGNED(16);
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2018-04-24 22:26:28 +03:00
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};
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struct target_rt_sigframe {
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uint32_t tramp[2]; /* not in kernel, which uses VDSO instead */
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struct target_siginfo info;
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struct target_ucontext uc;
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};
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static abi_ulong get_sigframe(struct target_sigaction *ka,
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CPURISCVState *regs, size_t framesize)
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{
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2018-04-11 22:23:47 +03:00
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abi_ulong sp = get_sp_from_cpustate(regs);
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2018-04-24 22:26:28 +03:00
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/* If we are on the alternate signal stack and would overflow it, don't.
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Return an always-bogus address instead so we will die with SIGSEGV. */
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2018-04-11 22:23:47 +03:00
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if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize))) {
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2018-04-24 22:26:28 +03:00
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return -1L;
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}
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2018-04-11 22:23:47 +03:00
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/* This is the X/Open sanctioned signal stack switching. */
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sp = target_sigsp(sp, ka) - framesize;
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/* XXX: kernel aligns with 0xf ? */
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sp &= ~3UL; /* align sp on 4-byte boundary */
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2018-04-24 22:26:28 +03:00
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return sp;
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}
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static void setup_sigcontext(struct target_sigcontext *sc, CPURISCVState *env)
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{
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int i;
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__put_user(env->pc, &sc->pc);
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for (i = 1; i < 32; i++) {
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__put_user(env->gpr[i], &sc->gpr[i - 1]);
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}
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for (i = 0; i < 32; i++) {
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__put_user(env->fpr[i], &sc->fpr[i]);
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}
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2019-01-15 02:58:23 +03:00
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uint32_t fcsr = riscv_csr_read(env, CSR_FCSR);
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2018-04-24 22:26:28 +03:00
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__put_user(fcsr, &sc->fcsr);
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}
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static void setup_ucontext(struct target_ucontext *uc,
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CPURISCVState *env, target_sigset_t *set)
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{
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__put_user(0, &(uc->uc_flags));
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__put_user(0, &(uc->uc_link));
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2018-04-11 22:23:47 +03:00
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target_save_altstack(&uc->uc_stack, env);
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2018-04-24 22:26:28 +03:00
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int i;
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for (i = 0; i < TARGET_NSIG_WORDS; i++) {
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__put_user(set->sig[i], &(uc->uc_sigmask.sig[i]));
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}
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setup_sigcontext(&uc->uc_mcontext, env);
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}
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static inline void install_sigtramp(uint32_t *tramp)
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{
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__put_user(0x08b00893, tramp + 0); /* li a7, 139 = __NR_rt_sigreturn */
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__put_user(0x00000073, tramp + 1); /* ecall */
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}
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void setup_rt_frame(int sig, struct target_sigaction *ka,
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target_siginfo_t *info,
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target_sigset_t *set, CPURISCVState *env)
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{
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abi_ulong frame_addr;
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struct target_rt_sigframe *frame;
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frame_addr = get_sigframe(ka, env, sizeof(*frame));
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trace_user_setup_rt_frame(env, frame_addr);
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if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
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goto badframe;
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}
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setup_ucontext(&frame->uc, env, set);
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tswap_siginfo(&frame->info, info);
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install_sigtramp(frame->tramp);
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env->pc = ka->_sa_handler;
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env->gpr[xSP] = frame_addr;
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env->gpr[xA0] = sig;
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env->gpr[xA1] = frame_addr + offsetof(struct target_rt_sigframe, info);
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env->gpr[xA2] = frame_addr + offsetof(struct target_rt_sigframe, uc);
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env->gpr[xRA] = frame_addr + offsetof(struct target_rt_sigframe, tramp);
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return;
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badframe:
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unlock_user_struct(frame, frame_addr, 1);
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if (sig == TARGET_SIGSEGV) {
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ka->_sa_handler = TARGET_SIG_DFL;
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}
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force_sig(TARGET_SIGSEGV);
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}
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static void restore_sigcontext(CPURISCVState *env, struct target_sigcontext *sc)
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{
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int i;
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__get_user(env->pc, &sc->pc);
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for (i = 1; i < 32; ++i) {
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__get_user(env->gpr[i], &sc->gpr[i - 1]);
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}
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for (i = 0; i < 32; ++i) {
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__get_user(env->fpr[i], &sc->fpr[i]);
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}
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uint32_t fcsr;
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__get_user(fcsr, &sc->fcsr);
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2019-01-15 02:58:23 +03:00
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riscv_csr_write(env, CSR_FCSR, fcsr);
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2018-04-24 22:26:28 +03:00
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}
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static void restore_ucontext(CPURISCVState *env, struct target_ucontext *uc)
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{
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sigset_t blocked;
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target_sigset_t target_set;
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int i;
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target_sigemptyset(&target_set);
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for (i = 0; i < TARGET_NSIG_WORDS; i++) {
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__get_user(target_set.sig[i], &(uc->uc_sigmask.sig[i]));
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}
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target_to_host_sigset_internal(&blocked, &target_set);
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set_sigmask(&blocked);
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restore_sigcontext(env, &uc->uc_mcontext);
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}
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long do_rt_sigreturn(CPURISCVState *env)
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{
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struct target_rt_sigframe *frame;
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abi_ulong frame_addr;
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frame_addr = env->gpr[xSP];
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trace_user_do_sigreturn(env, frame_addr);
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if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
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goto badframe;
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}
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restore_ucontext(env, &frame->uc);
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if (do_sigaltstack(frame_addr + offsetof(struct target_rt_sigframe,
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uc.uc_stack), 0, get_sp_from_cpustate(env)) == -EFAULT) {
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goto badframe;
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}
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unlock_user_struct(frame, frame_addr, 0);
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return -TARGET_QEMU_ESIGRETURN;
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badframe:
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unlock_user_struct(frame, frame_addr, 0);
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force_sig(TARGET_SIGSEGV);
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return 0;
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}
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