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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 FreeBSD
#ifndef TARGET_BSD
// 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 <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>
#include <sys/types.h>
#include <linux/unistd.h>
#include <errno.h>
ucontext_t *p_saved_ctxt;
unsigned savedESP;
void install_signal_handlers(void);
void segv_signal_handler(int, siginfo_t *, void *);
void usr2_signal_handler(int, siginfo_t *, void *);
void generate_segv(int val);
void printSignalMask()
{
sigset_t maskSet;
int maskBits;
sigprocmask(0, NULL, &maskSet);
int i;
for (i=32; i>0; i--)
maskBits = (maskBits << 1) | sigismember(&maskSet, i);
printf("signal mask: 0x%0.8x\n", maskBits);
}
void install_signal_handlers() {
//printf("installing signal handlers\n");
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 = segv_signal_handler;
p_sigaction->sa_flags = SA_SIGINFO;
/* mask all other signals */
sigfillset(&p_sigaction->sa_mask);
ret_val = sigaction(SIGSEGV, p_sigaction, NULL);
if(ret_val) {
perror("ERROR, sigaction failed");
exit(1);
}
p_sigaction->sa_sigaction = usr2_signal_handler;
p_sigaction->sa_flags = SA_SIGINFO;
ret_val = sigaction(SIGUSR2, p_sigaction, NULL);
if(ret_val) {
perror("ERROR, sigaction failed");
exit(1);
}
}
void generate_segv(int val) {
printf("bla segv\n");
int *p = 0;
printf("EIP of segfault: 0x%x\n", &&segfault);
__asm__ __volatile__ (
"movl $0x600D1, %eax;\
movl $0x600D2, %ebx;\
movl $0x600D3, %ecx;\
movl $0x600D4, %edx;\
movl $0x600D5, %edi;\
movl $0x600D6, %esi;\
movl $0x600D7, %ebp");
segfault:
__asm__ __volatile__ (
"movl (0x0), %ecx");
}
void segv_signal_handler(int signum, siginfo_t *siginfo, void *_uctxt) {
printf("bla segv handler\n");
int ret_val;
ucontext_t *uctxt = (ucontext_t *)_uctxt;
ucontext_t signal_ctxt;
pid_t tid;
printf("signal %d (captured EIP: 0x%x)\n", signum,
uctxt->uc_mcontext.gregs[REG_EIP]);
savedESP = uctxt->uc_mcontext.gregs[REG_ESP];
printf("ESP saved\n" );
printf("EDI: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EDI]);
printf("ESI: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_ESI]);
printf("EBP: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EBP]);
printf("EBX: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EBX]);
printf("EDX: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EDX]);
printf("ECX: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_ECX]);
printf("EAX: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EAX]);
printf("EIP: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EIP]);
printf("EFL: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EFL]);
tid = getpid();
ret_val = kill(tid, SIGUSR2);
}
void usr2_signal_handler(int signum, siginfo_t *siginfo, void *_uctxt) {
printf("bla u2\n");
int ret_val;
ucontext_t *uctxt = (ucontext_t *)_uctxt;
ucontext_t signal_ctxt;
pid_t tid;
printf("signal %d (captured EIP: 0x%x)\n", signum,
uctxt->uc_mcontext.gregs[REG_EIP]);
printf("ESP diff from saved: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_ESP] - savedESP);
printf("EDI: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EDI]);
printf("ESI: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_ESI]);
printf("EBP: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EBP]);
printf("EBX: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EBX]);
printf("EDX: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EDX]);
printf("ECX: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_ECX]);
printf("EAX: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EAX]);
printf("EIP: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EIP]);
// NOTE!
// Possible bug in pin: the resume flags don't match when running natively versus under pin
//printf("EFL: 0x%0.8x\n", uctxt->uc_mcontext.gregs[REG_EFL]);
// Change contexts
uctxt->uc_mcontext.gregs[REG_EDI] = p_saved_ctxt->uc_mcontext.gregs[REG_EDI];
uctxt->uc_mcontext.gregs[REG_ESI] = p_saved_ctxt->uc_mcontext.gregs[REG_ESI];
uctxt->uc_mcontext.gregs[REG_EBP] = p_saved_ctxt->uc_mcontext.gregs[REG_EBP];
uctxt->uc_mcontext.gregs[REG_ESP] = p_saved_ctxt->uc_mcontext.gregs[REG_ESP];
uctxt->uc_mcontext.gregs[REG_EBX] = p_saved_ctxt->uc_mcontext.gregs[REG_EBX];
uctxt->uc_mcontext.gregs[REG_EDX] = p_saved_ctxt->uc_mcontext.gregs[REG_EDX];
uctxt->uc_mcontext.gregs[REG_ECX] = p_saved_ctxt->uc_mcontext.gregs[REG_ECX];
uctxt->uc_mcontext.gregs[REG_EAX] = p_saved_ctxt->uc_mcontext.gregs[REG_EAX];
uctxt->uc_mcontext.gregs[REG_EIP] = p_saved_ctxt->uc_mcontext.gregs[REG_EIP];
uctxt->uc_mcontext.gregs[REG_EFL] = p_saved_ctxt->uc_mcontext.gregs[REG_EFL];
// getcontext() doesn't appear to properly set the segment registers,
// so don't mess with them.
//uctxt->uc_mcontext.gregs[REG_CS] = p_saved_ctxt->uc_mcontext.gregs[REG_CS];
//uctxt->uc_mcontext.gregs[REG_SS] = p_saved_ctxt->uc_mcontext.gregs[REG_SS];
//uctxt->uc_mcontext.gregs[REG_DS] = p_saved_ctxt->uc_mcontext.gregs[REG_DS];
//uctxt->uc_mcontext.gregs[REG_ES] = p_saved_ctxt->uc_mcontext.gregs[REG_ES];
//uctxt->uc_mcontext.gregs[REG_FS] = p_saved_ctxt->uc_mcontext.gregs[REG_FS];
//uctxt->uc_mcontext.gregs[REG_GS] = p_saved_ctxt->uc_mcontext.gregs[REG_GS];
free(p_saved_ctxt);
p_saved_ctxt = 0;
}
int main(int argc, char **argv) {
int ret_val;
p_saved_ctxt = malloc(sizeof(ucontext_t));
//printf("important 0x%0.8x\n",p_saved_ctxt);
install_signal_handlers();
//printf("important2 0x%0.8x\n",p_saved_ctxt);
int tmp = getcontext(p_saved_ctxt);
ret_val = tmp;
if (tmp) {
perror("ERROR, getcontext failed\n");
printf("%d, %d\n",ret_val,errno);
exit(1);
}
printf("bygal2\n");
p_saved_ctxt->uc_mcontext.gregs[REG_EIP] = (int)&&safe_exit;
generate_segv(1);
safe_exit:
printf("safe exit\n");
printSignalMask();
return 0;
}