#include <sys/types.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <semaphore.h>
#include <stdio.h>
#include <stdlib.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>

#define SEM_NAME "/semtst"

int test_unnamed(void);
int test_named(void);
int test_named2(void);

int
test_unnamed(void)
{
        sem_t *s;
        pid_t pid;
        int status;

        printf("testing unnamed process-shared semaphore\n");
        s = (sem_t *)mmap(NULL, sizeof(sem_t), PROT_READ|PROT_WRITE, MAP_ANON|MAP_SHARED,
                -1, 0);
        if (s == MAP_FAILED)
                err(1, "mmap failed");
        if (sem_init(s, 1, 0))
                err(2, "sem_init failed");
        if ((pid = fork()) == 0) {
                printf("child: sem_wait()\n");
                if (sem_wait(s))
                        err(3, "sem_wait failed");
                printf("child: sem_wait() returned\n");
                exit(0);
        } else {
                sleep(1);
                printf("parent: sem_post()\n");
                if (sem_post(s))
                        err(4, "sem_post failed");
                waitpid(pid, &status, 0);
                if (WIFEXITED(status) && WEXITSTATUS(status) == 0)
                        printf("OK.\n");
                else
                        printf("Failure.");
        }
        return (0);
}

int
test_named(void)
{
        sem_t *s, *s2;
        pid_t pid;
        int status;

        printf("testing named process-shared semaphore\n");
        sem_unlink(SEM_NAME);
        s = sem_open(SEM_NAME, O_CREAT, 0777, 0);
        if (s == SEM_FAILED)
                err(1, "sem_open failed");
        s2 = sem_open(SEM_NAME, O_CREAT, 0777, 0);
        if (s2 == SEM_FAILED)
                err(2, "second sem_open call failed");
        if (s != s2)
                errx(3,
"two sem_open calls for same semaphore do not return same address");
        if (sem_close(s2))
                err(4, "sem_close failed");
        if ((pid = fork()) == 0) {
                printf("child: sem_wait()\n");
                if (sem_wait(s))
                        err(5, "sem_wait failed");
                printf("child: sem_wait() returned\n");
                exit(0);
        } else {
                sleep(1);
                printf("parent: sem_post()\n");
                if (sem_post(s))
                        err(6, "sem_post failed");
                waitpid(pid, &status, 0);
                if (WIFEXITED(status) && WEXITSTATUS(status) == 0)
                        printf("OK.\n");
                else
                        printf("Failure.");
        }

        if (sem_close(s))
                err(7, "sem_close failed");
        
        return (0);
}

int
test_named2(void)
{
        sem_t *s, *s2, *s3;

        printf("testing named process-shared semaphore, O_EXCL cases\n");
        sem_unlink(SEM_NAME);
        s = sem_open(SEM_NAME, O_CREAT | O_EXCL, 0777, 0);
        if (s == SEM_FAILED)
                err(1, "sem_open failed");
        s2 = sem_open(SEM_NAME, O_CREAT | O_EXCL, 0777, 0);
        if (s2 != SEM_FAILED)
                errx(2, "second sem_open call wrongly succeeded");
        if (errno != EEXIST)
                err(3, "second sem_open call failed with wrong errno");

        s3 = sem_open(SEM_NAME, 0);
        if (s3 == SEM_FAILED)
                err(4, "third sem_open call failed");
        if (s != s3)
                errx(5,
"two sem_open calls for same semaphore do not return same address");
        if (sem_close(s3))
                err(6, "sem_close failed");

        if (sem_close(s))
                err(7, "sem_close failed");
        
        printf("OK.\n");
        return (0);
}

int
main(void)
{
        test_unnamed();
        test_named();
        test_named2();
        return (0);
}