SIG35-C. Do not return from SIGSEGV, SIGILL, or SIGFPE signal handlers

According to section 7.14.1.1 (signals) of the C standard; returning from a SIGSEGV, SIGILL, or SIGFPE signal handler is undefined behavior.

Noncompliant Code Example

In this non-compliant code example, if the given user input is '0', the division operation causes a SIGFPE signal to be sent to the program.

volatile sig_atomic_t denom;
void sighandle(int s);
int main(int argc,char *argv[]){
  if(argc < 2)
    return 0;

  int result = 0;
   denom = atoi(argv[1]);

  signal(SIGFPE,(*sighandle));

  result = 100/denom;
  return 0;
}

void sighandle(int s){
  /* Fix the offending volatile */                   
  if(denom == 0)
    denom == 1;
  /* Everything is ok */
  return;
}

The above example will loop infinitely on most systems when supplied with 0 as an argument.
This illustrates that even when a SIGFPE handler attempts to fix the error condition while obeying all other rules of signal handling, the behavior may not be as expected.

Compliant Solution

void sighandle(int s){
  /* No recovery */
  abort();
}

The only safe way to leave a SIGFPE,SIGILL, or SIGSEGV handler is through abort or _exit/_Exit.

Risk Assessment

Attempting to handle SIGSEGV/SIGILL/or SIGFPE signals is rare.