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/*
* Copyright 2002-2019 Intel Corporation.
*
* This software is provided to you as Sample Source Code as defined in the accompanying
* End User License Agreement for the Intel(R) Software Development Products ("Agreement")
* section 1.L.
*
* This software and the related documents are provided as is, with no express or implied
* warranties, other than those that are expressly stated in the License.
*/
// features.h does not exist on macOS*
#ifdef TARGET_LINUX
// features initializes the system's state, including the state of __USE_GNU
#include <features.h>
#endif
// If __USE_GNU is defined, we don't need to do anything.
// If we defined it ourselves, we need to undefine it later.
#ifndef __USE_GNU
#define __USE_GNU
#define APP_UNDEF_USE_GNU
#endif
#include <sys/ucontext.h>
// If we defined __USE_GNU ourselves, we need to undefine it here.
#ifdef APP_UNDEF_USE_GNU
#undef __USE_GNU
#undef APP_UNDEF_USE_GNU
#endif
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <assert.h>
#include <setjmp.h>
int p_safe_exit;
void install_signal_handler(void);
void signal_handler(int, siginfo_t *, void *);
void generate_hlt_segv(int val);
void install_signal_handler() {
int ret_val;
struct sigaction s_sigaction;
struct sigaction *p_sigaction = &s_sigaction;
/* Register the signal hander using the siginfo interface*/
p_sigaction->sa_sigaction = signal_handler;
p_sigaction->sa_flags = SA_SIGINFO;
/* Don't mask any other signals */
sigemptyset(&p_sigaction->sa_mask);
ret_val = sigaction(SIGSEGV, p_sigaction, NULL);
if(ret_val) {
perror("ERROR, sigaction failed");
exit(1);
}
}
void generate_hlt_segv(int val) {
int *p = 0;
p_safe_exit = (int)&&safe_exit;
printf("EIP of segfault: 0x%x (only accurate with if compiled with -O)\n", (int)&&hlt_segfault);
hlt_segfault:
__asm__ __volatile__ ("hlt");
printf("ERROR!\n");
safe_exit:
printf("EIP of safe exit: 0x%x\n", p_safe_exit);
}
void signal_handler(int signum, siginfo_t *siginfo, void *_uctxt) {
int ret_val;
ucontext_t *uctxt = (ucontext_t *)_uctxt;
ucontext_t signal_ctxt;
#if defined(TARGET_MAC)
printf("signal %d (captured EIP: 0x%x)\n", signum,
uctxt->uc_mcontext->__ss.__eip);
uctxt->uc_mcontext->__ss.__eip = p_safe_exit;
#else
printf("signal %d (captured EIP: 0x%x)\n", signum,
uctxt->uc_mcontext.gregs[REG_EIP]);
uctxt->uc_mcontext.gregs[REG_EIP] = p_safe_exit;
#endif
}
int main(int argc, char **argv) {
install_signal_handler();
generate_hlt_segv(1);
return 0;
}