/* To enable core dumps: ulimit -c <size> */
/* To inquire on size:   ulimit -c */
/* To process a dump:    gdb waitpid core */

#include <stdio.h>      /* perror, ... */
#include <stdlib.h>     /* exit, ... */
#include <string.h>     /* strsignal, ... */
#include <sys/types.h>  /* pid_t, ... */
#include <sys/wait.h>   /* waitpid, ... */
#include <unistd.h>     /* fork, ... */

#define CHILD 0
#define FORK_ERROR -1

typedef int (*child)(void);

static void fork_with_child(child function);
static void wait_for_child(pid_t pid);

static int normal_child();
static int abort_child();
static int divide_by_zero();
static int raise_sigsegv();

static const int CHILD_RC = 42;

int main(int argc, char *argv[]) {

	fork_with_child(normal_child);
	fork_with_child(abort_child);
	fork_with_child(divide_by_zero);
	fork_with_child(raise_sigsegv);

	printf("\n");
	return EXIT_SUCCESS;
}

static void fork_with_child(child function) {

	pid_t child_pid;

	switch ( (child_pid = fork()) ) {
		case FORK_ERROR:
			perror("fork");
			exit(1);
		case CHILD:
			exit(function());
		default:
			wait_for_child(child_pid);
			break;
	}
}

static void wait_for_child(pid_t child_pid) {

	int child_status;
	waitpid(child_pid, &child_status, 0);

	if ( WIFEXITED(child_status) ) {
		printf("child exited with rc %d\n", WEXITSTATUS(child_status));
	}
	else if ( WIFSIGNALED(child_status) ) {
		printf("child exited with signal %s\n", strsignal(WTERMSIG(child_status)));
		if ( WCOREDUMP(child_status) ) {
			printf("core dump produced\n");
		}
	}
}

static int normal_child() {
	printf("\nnormal_child returning %d\n", CHILD_RC);
	return CHILD_RC;
}

static int abort_child() {
	printf("\nabort_child aborting\n");
	abort();
	return EXIT_SUCCESS; /* Should not reach this */
}

static int divide_by_zero() {

	int i = 1;
	int j = 0;

	printf("\ndivide_by_zero dividing by zero\n");
	fflush(stdout);
	i /= j;

	return EXIT_SUCCESS; /* Should not reach this */
}

static int raise_sigsegv() {
	printf("\nraise_sigsegv raising SIGSEGV\n");
	raise(SIGSEGV);
	return EXIT_SUCCESS; /* Should not reach this */
}