evdns_test.c

/*
 * Usage:
 *	% cc -DDEBUG -o evdns_test evdns_test.c -levent
 *	% ./evdns_test
 */
#include <sys/param.h>
#include <sys/time.h>

#include <event2/event.h>
#include <event2/event_struct.h>
#include <event2/dns.h>
#include <stdlib.h>
#include <assert.h>

#ifndef nitems
#define nitems(_x)	(sizeof(_x) / sizeof((_x)[0]))
#endif

#ifdef DEBUG
#define DBG(_x)	printf _x
#else
#define DBG(_x)
#endif

static struct event ev_periodic;
static int result[] = { -1, -1 };

static void  periodic (int, short, void *);
static void  on_resolved (int, char, int, int, void *, void *);

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

	event_init();

	evdns_init();
	evdns_clear_nameservers_and_suspend();

	/* nameserver doesn't work */
	evdns_nameserver_ip_add("127.0.0.2");

	/* below requests will be error by shutdown */
	evdns_resolve_ipv4("www.iij.ad.jp", 0, on_resolved, (void *)0); 
	evdns_resolve_ipv4("www.iij.ad.jp", 0, on_resolved, (void *)1); 

	periodic(-1, 0, NULL);

	event_loop(0);	/* see periodic() */

	assert(result[0] == DNS_ERR_SHUTDOWN);
	assert(result[1] == DNS_ERR_SHUTDOWN);

	exit(EXIT_SUCCESS);
}

static void
periodic(int fd, short ev, void *ctx)
{
	static int step = 0;
	struct timeval tv = { 1, 0 };

	++step;

	DBG(("%s(%d)\n", __func__, step));

	switch (step) {
	case 1:
		/* reconfigure */
		evdns_clear_nameservers_and_suspend();
		evdns_nameserver_ip_add("127.0.0.2");
		break;
	case 2:
		/* shutdown */
		evdns_shutdown(1);
		break;
	case 8:
		/* (try to) stop this program */
		event_del(&ev_periodic);
		return;
	}

	event_set(&ev_periodic, -1, 0, periodic, ctx);
	event_add(&ev_periodic, &tv);
}

static void
on_resolved(int res, char t, int c, int ttl, void *addr, void *arg)
{
	int ival = (intptr_t)arg;

	DBG(("%s(result[%d]=%d)\n", __func__, ival, res));

	assert(0 <= ival);
	assert(ival < nitems(result));
	result[ival] = res;
}