#include <stdio.h>

#include <fcntl.h>

#include <unistd.h>

#include <errno.h>

#include <string.h>

#include <sys/wait.h>

#include "test.h"

#define TEST(c, ...) ((c) ? 1 : (error(#c" failed: " __VA_ARGS__),0))

#define TESTE(c) (errno=0, TEST(c, "errno = %s\n", strerror(errno)))

int main(void)

{

	struct flock fl = {0};

	FILE *f;

	int fd;

	pid_t pid;

	int status;

	if (!TESTE(f=tmpfile())) return test_status;

	fd = fileno(f);

	fl.l_type = F_WRLCK;

	fl.l_whence = SEEK_SET;

	fl.l_start = 0;

	fl.l_len = 0;

	TESTE(fcntl(fd, F_SETLK, &fl)==0);

	pid = fork();

	if (!pid) {

		fl.l_type = F_RDLCK;

		_exit(fcntl(fd, F_SETLK, &fl)==0 ||

			(errno!=EAGAIN && errno!=EACCES));

	}

	while (waitpid(pid, &status, 0)<0 && errno==EINTR);

	TEST(status==0, "lock failed to work\n");

	pid = fork();

	if (!pid) {

		fl.l_type = F_WRLCK;

		_exit(fcntl(fd, F_GETLK, &fl) || fl.l_pid != getppid());

	}

	while (waitpid(pid, &status, 0)<0 && errno==EINTR);

	TEST(status==0, "child failed to detect lock held by parent\n");

	fclose(f);

	return test_status;

}