fileops/disklabel.c

   1 /* compile with:
   2    gcc disklabel.c -o disklabel -Wall -W -Wextra -ansi -pedantic
   3
   4    Each disk on a system may contain a disk label which provides
   5    detailed information about the geometry of the disk and the
   6    partitions into which the disk is divided.
   7
   8    A copy of the in-core label for a disk can be obtained with the
   9    DIOCGDINFO ioctl(2); this works with a file descriptor for a block or
  10    character (``raw'') device for any partition of the disk.
  11
  12    For more information consult disklabel(5) man page.
  13 */
  14
  15 #include <fcntl.h>
  16 #include <stdio.h>
  17 #include <stdlib.h>
  18 #include <unistd.h>
  19 #include <sys/disklabel.h>
  20 #include <sys/ioctl.h>
  21
  22 int main(int argc, char *argv[])
  23 {
  24     struct disklabel dklbl;
  25     int fd;
  26
  27     /* check argument count */
  28     if (argc != 2) {
  29         fprintf(stderr, "usage: %s /dev/file\n", argv[0]);
  30         exit(EXIT_FAILURE);
  31     }
  32
  33     /* open device file */
  34     if ((fd = open(argv[1], O_RDONLY)) == -1) {
  35         perror("open");
  36         exit(EXIT_FAILURE);
  37     }
  38
  39     /* get disklabel by calling a disk-specific ioctl */
  40     if (ioctl(fd, DIOCGDINFO, &dklbl) == -1) {
  41         perror("ioctl");
  42         close(fd);
  43         exit(EXIT_FAILURE);
  44     }
  45
  46     printf("Disk: %s\n", dklbl.d_typename);
  47
  48     return EXIT_SUCCESS;
  49 }