#include <sys/types.h>
#include <sys/sem.h>
#include <time.h>
#include "usg_common.h"

int
main(int argc, char *argv[])
{
    struct semid_ds ds;
    union semun arg, dummy;             /* Fourth argument for semctl() */
    int semid, j;

    if (argc != 2 || strcmp(argv[1], "--help") == 0)
        err_exit(0, "%s semid\n", argv[0]);

    semid = atoi(argv[1]);

    arg.buf = &ds;
    if (semctl(semid, 0, IPC_STAT, arg) == -1)
        err_exit(errno, "semctl");

    printf("Semaphore changed: %s", ctime(&ds.sem_ctime));
    printf("Last semop():      %s", ctime(&ds.sem_otime));

    /* Display per-semaphore information */

    arg.array = (short unsigned int*)calloc(ds.sem_nsems, sizeof(arg.array[0]));
    if (arg.array == NULL)
        err_exit(errno, "calloc");
    if (semctl(semid, 0, GETALL, arg) == -1)
        err_exit(errno, "semctl-GETALL");

    printf("Sem #  Value  SEMPID  SEMNCNT  SEMZCNT\n");

    for (j = 0; j < ds.sem_nsems; j++)
        printf("%3d   %5d   %5d  %5d    %5d\n", j, arg.array[j],
                semctl(semid, j, GETPID, dummy),
                semctl(semid, j, GETNCNT, dummy),
                semctl(semid, j, GETZCNT, dummy));

    exit(EXIT_SUCCESS);
}