#define _GNU_SOURCE
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <signal.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/syscall.h>

static int value = -1;

#define FUTEX_WAIT		0
#define FUTEX_WAKE		1

static int futex(int32_t *uaddr, int op, int32_t val,
		const struct timespec *timeout, int32_t *uaddr2, int32_t val3)
{
	return syscall(__NR_futex, uaddr, op, val, timeout,
			uaddr2, val3);
}

static void sighandler(int signo, siginfo_t *siginfo, void *context)
{
	fprintf(stderr, "[OK] Test program with pid: %d SIGUSR1 handler\n",
		getpid());
}

int main(int argc, char **argv)
{
	struct sigaction act;
	pid_t pid, wait_pid;
	int ret;

	fprintf(stderr, "Testing futex sigrestart. Stop with CTRL-c.\n",
		getpid());
	act.sa_sigaction = sighandler;
	act.sa_flags = SA_SIGINFO | SA_RESTART;
	//act.sa_flags = SA_SIGINFO;
	sigemptyset(&act.sa_mask);
	ret = sigaction(SIGUSR1, &act, NULL);
	if (ret)
		abort();

	pid = fork();
	if (pid > 0) {
		/* parent */
		for (;;) {
			ret = kill(pid, SIGUSR1);
			if (ret) {
				perror("kill");
				abort();
			}
			sleep(1);
		}
	} else {
		if (pid < 0) {
			abort();
		}
		/* child */
		for (;;) {
			ret = futex(&value, FUTEX_WAIT, -1, NULL, NULL, 0);
			if (ret < 0) {
				fprintf(stderr, "[FAIL] futex returns %d, %s\n",
					ret, strerror(errno));
			} else {
				fprintf(stderr, "[FAIL] futex returns %d (unexpected)\n",
					ret);
			}
		}
	}

	return 0;
}