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November 12, 2017 17:53
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#ifndef _GNU_SOURCE | |
#define _GNU_SOURCE | |
#endif | |
#include <unistd.h> | |
#include <signal.h> | |
#include <stdio.h> | |
#include <stdlib.h> | |
#include <sys/types.h> | |
#include <sys/wait.h> | |
#include <signal.h> | |
#include <sys/ucontext.h> | |
#include <ucontext.h> | |
void setHandler(void (*handler)(int,siginfo_t *,void *)) | |
{ | |
struct sigaction action; | |
action.sa_flags = SA_SIGINFO; | |
action.sa_sigaction = handler; | |
if (sigaction(SIGFPE, &action, NULL) == -1) { | |
perror("sigusr: sigaction"); | |
_exit(1); | |
} | |
if (sigaction(SIGSEGV, &action, NULL) == -1) { | |
perror("sigusr: sigaction"); | |
_exit(1); | |
} | |
if (sigaction(SIGILL, &action, NULL) == -1) { | |
perror("sigusr: sigaction"); | |
_exit(1); | |
} | |
if (sigaction(SIGBUS, &action, NULL) == -1) { | |
perror("sigusr: sigaction"); | |
_exit(1); | |
} | |
} | |
void continue_after_crash(void) | |
{ | |
printf("normal running now\n"); | |
exit(0); | |
} | |
void catchit(int signo, siginfo_t *info, void *extra) | |
{ | |
ucontext_t *p=(ucontext_t *)extra; | |
int x; | |
printf("Signal %d received from parent\n", signo); | |
printf("siginfo address=%x\n",info->si_addr); | |
x= p->uc_mcontext.gregs[REG_RIP]; | |
// x= p->uc_mcontext.arm_pc; | |
printf("address = %x\n",x); | |
// uncomment one of the following lines | |
//p->uc_mcontext.gregs[REG_RIP] += 6; | |
//setHandler(SIG_DFL); | |
//p->uc_mcontext.gregs[REG_RIP] = (unsigned int)continue_after_crash; | |
//abort(); | |
} | |
int main() | |
{ | |
int x=9,y=0,z=10; | |
int *p=NULL; | |
setHandler(catchit); | |
p=0x90; // put a wrong address | |
*p=100; | |
printf("Alive???\n"); | |
z=x/y; | |
printf("%d\n",z); | |
return 0; | |
} | |
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An interesting article and example. Gcc warns that those %x should be %p