Source of /tests/kqueue_close.c (From xnu-11215.1.10)

#include <unistd.h>
#include <pthread.h>
#include <errno.h>

#include <sys/event.h>
#include <mach/mach.h>
#include <mach/mach_port.h>

#include <Block.h>
#include <darwintest.h>

T_GLOBAL_META(T_META_RUN_CONCURRENTLY(true));

/*
 * <rdar://problem/30231213> close() of kqueue FD races with kqueue_scan park
 *
 * When close concurrent with poll goes wrong, the close hangs
 * and the kevent never gets any more events.
 */

/* Both events should fire at about the same time */
static uint32_t timeout_ms = 10;

static void *
poll_kqueue(void *arg)
{
	int fd = (int)arg;

	struct kevent kev = {
		.filter = EVFILT_TIMER,
		.flags  = EV_ADD,
		.data   = timeout_ms,
	};

	int rv = kevent(fd, &kev, 1, NULL, 0, NULL);

	if (rv == -1 && errno == EBADF) {
		/* The close may race with this thread spawning */
		T_LOG("kqueue already closed?");
		return NULL;
	} else {
		T_QUIET; T_ASSERT_POSIX_SUCCESS(rv, "kevent");
	}

	while ((rv = kevent(fd, NULL, 0, &kev, 1, NULL)) == 1) {
		T_LOG("poll\n");
	}

	if (rv != -1 || errno != EBADF) {
		T_ASSERT_POSIX_SUCCESS(rv, "fd should be closed");
	}

	return NULL;
}

static void
run_test(void)
{
	int fd = kqueue();
	T_QUIET; T_ASSERT_POSIX_SUCCESS(fd, "kqueue");

	pthread_t thread;
	int rv = pthread_create(&thread, NULL, poll_kqueue,
	    (void *)(uintptr_t)fd);
	T_QUIET; T_ASSERT_POSIX_SUCCESS(rv, "pthread_create");

	usleep(timeout_ms * 1000);

	rv = close(fd);
	T_ASSERT_POSIX_SUCCESS(rv, "close");

	rv = pthread_join(thread, NULL);
	T_QUIET; T_ASSERT_POSIX_SUCCESS(rv, "pthread_join");
}

T_DECL(kqueue_close_race, "Races kqueue close with kqueue process",
    T_META_LTEPHASE(LTE_POSTINIT), T_META_TIMEOUT(5), T_META_TAG_VM_PREFERRED)
{
	for (uint32_t i = 1; i < 100; i++) {
		run_test();
	}
}

static void *
pthread_async_do(void *arg)
{
	void (^block)(void) = arg;
	block();
	Block_release(block);
	pthread_detach(pthread_self());
	return NULL;
}

static void
pthread_async(void (^block)(void))
{
	pthread_t th;
	int rc;

	rc = pthread_create(&th, NULL, pthread_async_do, Block_copy(block));
	T_QUIET; T_ASSERT_POSIX_SUCCESS(rc, "pthread_create");
}

T_DECL(kqueue_filter_close,
    "Check closing a kqfile with various filters works, rdar://72542450", T_META_TAG_VM_PREFERRED)
{
	mach_port_t mp, pset;
	kern_return_t kr;
	struct kevent ke;
	int kq, rc;
	int pfd[2];

	kq = kqueue();
	T_ASSERT_POSIX_SUCCESS(kq, "kqueue()");

	kr = mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_RECEIVE, &mp);
	T_QUIET; T_EXPECT_MACH_SUCCESS(kr, "mach_port_allocate(RECEIVE)");

	ke = (struct kevent){
		.filter = EVFILT_MACHPORT,
		.flags  = EV_ADD,
		.ident  = mp,
	};
	rc = kevent(kq, &ke, 1, NULL, 0, NULL);
	T_EXPECT_POSIX_SUCCESS(rc, "kevent(mp)");

	kr = mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_PORT_SET, &pset);
	T_QUIET; T_EXPECT_MACH_SUCCESS(kr, "mach_port_allocate(PSET)");

	ke = (struct kevent){
		.filter = EVFILT_MACHPORT,
		.flags  = EV_ADD,
		.ident  = pset,
	};
	rc = kevent(kq, &ke, 1, NULL, 0, NULL);
	T_EXPECT_POSIX_SUCCESS(rc, "kevent(pset)");

	rc = pipe(pfd);
	T_EXPECT_POSIX_SUCCESS(rc, "pipe");

	ke = (struct kevent){
		.filter = EVFILT_READ,
		.flags  = EV_ADD,
		.ident  = (unsigned long)pfd[0],
	};
	rc = kevent(kq, &ke, 1, NULL, 0, NULL);
	T_EXPECT_POSIX_SUCCESS(rc, "kevent(fd)");

	pthread_async(^{
		sleep(1);
		T_EXPECT_POSIX_SUCCESS(close(kq), "close");
	});

	rc = kevent(kq, NULL, 0, &ke, 1, NULL);
	T_EXPECT_POSIX_FAILURE(rc, EBADF, "kevent(closed fd) returns EBADF");
}