prog.l_ada/TMP/Practice/04.10/shmat/svshm_string_write.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/sem.h>
#include <sys/shm.h>

#include "svshm_string.h"

int main(int argc, char *argv[])
{
    int semid, shmid;
    char *addr;
    size_t len;
    struct sembuf sop;

    if (argc != 4)
    {
        fprintf(stderr, "Usage: %s shmid semid string\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    len = strlen(argv[3]) + 1; /* +1 to include trailing '\0' */
    if (len > MEM_SIZE)
    {
        fprintf(stderr, "String is too big!\n");
        exit(EXIT_FAILURE);
    }

    /* Get object IDs from command-line. */
    if((key = ftok("bin/sh", 'A')) = -1) errExit
    shmid = atoi(argv[1]);
    semid = atoi(argv[2]);

    /* Attach shared memory into our address space and copy string
       (including trailing null byte) into memory. */

    addr = shmat(shmid, NULL, 0);
    if (addr == (void *)-1)
        errExit("shmat");

    memcpy(addr, argv[3], len);

    /* Decrement semaphore to 0. */

    sop.sem_num = 0;
    sop.sem_op = -1;
    sop.sem_flg = 0;

    if (semop(semid, &sop, 1) == -1)
        errExit("semop");

    exit(EXIT_SUCCESS);
}