fileops/disklabel.c

   1 /*
   2  * Compile with:
   3  * gcc disklabel.c -o disklabel -Wall -W -Wextra -ansi -pedantic
   4  *
   5  * Each disk on a system may contain a disk label which provides
   6  * detailed information about the geometry of the disk and the
   7  * partitions into which the disk is divided.
   8  *
   9  * A copy of the in-core label for a disk can be obtained with the
  10  * DIOCGDINFO ioctl(2); this works with a file descriptor for a block or
  11  * character (``raw'') device for any partition of the disk.
  12
  13  * For more information consult disklabel(5) man page.
  14 */
  15
  16 #include <fcntl.h>
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <unistd.h>
  20 #include <sys/disklabel.h>
  21 #include <sys/ioctl.h>
  22
  23 int main(int argc, char *argv[])
  24 {
  25     struct disklabel dklbl;
  26     int fd;
  27
  28     /* Check argument count */
  29     if (argc != 2) {
  30         fprintf(stderr, "Usage: %s /dev/file\n", argv[0]);
  31         exit(EXIT_FAILURE);
  32     }
  33
  34     /* Open device file */
  35     if ((fd = open(argv[1], O_RDONLY)) == -1) {
  36         perror("open()");
  37         exit(EXIT_FAILURE);
  38     }
  39
  40     /* Get disklabel by calling a disk-specific ioctl */
  41     if (ioctl(fd, DIOCGDINFO, &dklbl) == -1) {
  42         perror("ioctl()");
  43         close(fd);
  44         exit(EXIT_FAILURE);
  45     }
  46
  47     printf("Disk: %s\n", dklbl.d_typename);
  48
  49     return EXIT_SUCCESS;
  50 }