如何与shm_open共享struct？

Question

我想知道如何从客户端到守护进程共享结构？我尝试了这个，但它不起作用：

daemon.c：

int main()
{
    struct data *d;
    printf("shm_open\n");
    if (shm_unlink("/MYSHM") != 0) {
        perror("In shm_unlink()");
        exit(1);
    }
    int fd = shm_open("/MYSHM", O_RDWR|O_CREAT, 0);

    if(fd == -1) {
      perror("shm_open");
      return 1;
    }
    printf("ftruncate\n");
    ftruncate(fd, sizeof(struct data));
    printf("mmap\n");
    d = mmap(NULL, sizeof(struct data), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
    int i =0;
    int j =0;
    struct data *d2;
    d2 = malloc(sizeof(struct data *)*950);
    d2 = d;
    printf("loop\n");
    while(d->command[0] == NULL){
        sleep(1);
    }
    while(strlen(d->command[j]) != 0){
       if(strcmp(d2->command[i], ",") == 0){
           execCmd(d2);
           i = -1;
       }
       else{
           d2->command[i] = malloc(strlen(d->command[i]));
           d2->command[i] = d->command[i];
       }
       i++;
       j++;
    }
    return EXIT_SUCCESS;
}

守护进程等待shm填充结构数据，然后将值分配给其他结构。

client.c：

int main(int argc, char *argv[])
{
      if(argc < 2){
        perror("pas assez d'arguments");
        exit(EXIT_FAILURE);
      }
      struct data *d;
      int fd;
      if (shm_unlink("/MYSHM") != 0) {
       printf("no shm existing");
      }
      if((fd = shm_open("/MYSHM", O_RDWR|O_TRUNC|O_EXCL|O_CREAT, S_IRUSR | S_IREAD| S_IWUSR | S_IWGRP | S_IXUSR |S_IEXEC | S_IRWXG)) < 0) {
            perror("shm_open");
            exit(EXIT_FAILURE);
      }

      ftruncate(fd, sizeof(struct data));
      d = mmap(NULL, sizeof(struct data), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);

      d->pipe1 = argv[1];
      d->tube2 = argv[2];
      int j;
      for (j = 3; j < argc; j++)
      {
        d->command[j - 3] = malloc((strlen(argv[j]) + strlen(argv[j]) + 1) * sizeof(char));
        strcpy(d->command[j - 3], argv[j]);
      }

}

客户端将结构发送给shm。