/*      $OpenBSD: sem_wait.c,v 1.3 2012/03/03 09:51:00 guenther Exp $   */
/*
 * Martin Pieuchot <mpi@openbsd.org>, 2011. Public Domain.
 */

#include <err.h>
#include <errno.h>
#include <unistd.h>
#include <semaphore.h>
#include <signal.h>
#include <pthread.h>
#include "test.h"


void *waiter(void *arg);

void
handler(int sig)
{
        static char message[] = "got sig\n";

        write(STDERR_FILENO, message, sizeof(message) - 1);
}

sem_t sem;
volatile int posted = 0, eintr_ok = 0;

int
main(int argc, char **argv)
{
        pthread_t th;
        struct sigaction sa;

        CHECKn(sem_wait(&sem));
        ASSERT(errno == EINVAL);

        CHECKr(sem_init(&sem, 0, 0));

        CHECKr(pthread_create(&th, NULL, waiter, &sem));

        sleep(1);

        printf("expect: sem_destroy on semaphore with waiters!\n");
        CHECKn(sem_destroy(&sem));
        ASSERT(errno == EBUSY);

        posted = 1;
        CHECKr(sem_post(&sem));
        CHECKr(pthread_join(th, NULL));

        /* test that sem_wait() resumes after handling a signal */
        memset(&sa, 0, sizeof sa);
        sa.sa_handler = &handler;
        sigemptyset(&sa.sa_mask);
        sa.sa_flags = 0;
        if (sigaction(SIGUSR1, &sa, NULL))
                err(1, "sigaction");
        posted = 0;
        CHECKr(pthread_create(&th, NULL, waiter, &sem));
        sleep(1);
        fprintf(stderr, "sending sig\n");
        eintr_ok = 1;
        pthread_kill(th, SIGUSR1);
        sleep(1);
        fprintf(stderr, "posting\n");
        posted = 1;
        eintr_ok = 0;
        CHECKr(sem_post(&sem));
        CHECKr(pthread_join(th, NULL));

        CHECKe(sem_destroy(&sem));

        SUCCEED;
}

void *
waiter(void *arg)
{
        sem_t *semp = arg;
        int value;
        int r;

        r = sem_wait(semp);
        CHECKr(sem_getvalue(semp, &value));
        if (r == 0) {
                ASSERT(value == 0);
                ASSERT(posted != 0);
        } else {
                ASSERT(r == -1);
                ASSERT(errno == EINTR);
                ASSERT(eintr_ok);
                if (posted)
                        ASSERT(value == 1);
                else
                        ASSERT(value == 0);
        }

        return (NULL);
}