Segmentation fault handling

Question

I have an application which I use to catch any segmentation fault or ctrl-c. Using the below code, I am able to catch the segmentation fault but the handler is being called

Answer 1

I do not agree at all with the statement "Don't catch the SIGSEGV".

That's a pretty good pratice to deal with unexpected conditions. And that's much cleaner to cope with NULL pointers (as given by malloc failures) with signal mechanism associated to setjmp/longjmp, than to distribute error condition management all along your code.

Note however that if you use ''sigaction'' on SEGV, you must not forget to say SA_NODEFER in sa_flags - or find another way to deal with the fact SEGV will trigger your handler just once.

#include <setjmp.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>

static void do_segv()
{
  int *segv;

  segv = 0; /* malloc(a_huge_amount); */

  *segv = 1;
}

sigjmp_buf point;

static void handler(int sig, siginfo_t *dont_care, void *dont_care_either)
{
   longjmp(point, 1);
}

int main()
{
  struct sigaction sa;

  memset(&sa, 0, sizeof(sigaction));
  sigemptyset(&sa.sa_mask);

  sa.sa_flags     = SA_NODEFER;
  sa.sa_sigaction = handler;

  sigaction(SIGSEGV, &sa, NULL); /* ignore whether it works or not */ 

  if (setjmp(point) == 0)
   do_segv();

  else
    fprintf(stderr, "rather unexpected error\n");

  return 0;
}