mknod.c

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

static int usage()
{
    fprintf(stderr,"mknod <path> <type> [major] [minor]\n");
    fprintf(stderr,"    type: b|c|p (block|character|pipe)\n");
    return 1;
}

int mknod_main(int argc, char *argv[])
{
    if (argc < 3) {
         return usage();
    }

    char *path;
    char type;
    dev_t dev = 0;
    int major, minor;
    mode_t mode = 0600;

    path = argv[1];
    type = argv[2][0];

    switch (type) {
    case 'b':
         mode |= S_IFBLK;
         if (argc != 5) return usage();
         break;
    case 'c':
         mode |= S_IFCHR;
         if (argc != 5) return usage();
         break;
    case 'p':
         mode |= S_IFIFO;
         break;
    default:
        return usage();
    }

    if (type == 'b' || type == 'c') {
      major = strtol(argv[3], NULL, 0);
      minor = strtol(argv[4], NULL, 0);
      dev = makedev(major, minor);
    }

    if (mknod(path, mode, dev) == -1) {
      perror("mknod");
      return 1;
    }
    return 0;
}