#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <guestfs.h>

static int
compare_keys_len (const void *p1, const void *p2)
{
  const char *key1 = * (char * const *) p1;
  const char *key2 = * (char * const *) p2;
  return strlen (key1) - strlen (key2);
}

static size_t
count_strings (char *const *argv)
{
  size_t c;

  for (c = 0; argv[c]; ++c)
    ;
  return c;
}

int                                                                            
main (int argc, char *argv[])
{
  guestfs_h *g;
  const char *disk;
  char **roots, *root, *str, **mountpoints, **lines;
  size_t i, j;

  if (argc != 2) {
    fprintf (stderr, "usage: inspect_vm disk.img\n");
    exit (EXIT_FAILURE);
  }
  disk = argv[1];

  g = guestfs_create ();
  if (g == NULL) {
    perror ("failed to create libguestfs handle");
    exit (EXIT_FAILURE);
  }

  /* Attach the disk image read-only to libguestfs. */
  if (guestfs_add_drive_opts (g, disk,
     /* GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw", */
        GUESTFS_ADD_DRIVE_OPTS_READONLY, 1,
        -1) /* this marks end of optional arguments */
      == -1)
    exit (EXIT_FAILURE);

  /* Run the libguestfs back-end. */
  if (guestfs_launch (g) == -1)
    exit (EXIT_FAILURE);

  /* Ask libguestfs to inspect for operating systems. */
  roots = guestfs_inspect_os (g);
  if (roots == NULL)
    exit (EXIT_FAILURE);
  if (roots[0] == NULL) {
    fprintf (stderr, "inspect_vm: no operating systems found\n");
    exit (EXIT_FAILURE);
  }

  for (j = 0; roots[j] != NULL; ++j) {
    root = roots[j];

    printf ("Root device: %s\n", root);

    /* Print basic information about the operating system. */
    str = guestfs_inspect_get_product_name (g, root);
    if (str)
      printf ("  Product name: %s\n", str);
    free (str);

    printf ("  Version:      %d.%d\n",
            guestfs_inspect_get_major_version (g, root),
            guestfs_inspect_get_minor_version (g, root));

    str = guestfs_inspect_get_type (g, root);
    if (str)
      printf ("  Type:         %s\n", str);
    free (str);
    str = guestfs_inspect_get_distro (g, root);
    if (str)
      printf ("  Distro:       %s\n", str);
    free (str);

    /* Mount up the disks, like guestfish -i.
     *
     * Sort keys by length, shortest first, so that we end up
     * mounting the filesystems in the correct order.
     */
    mountpoints = guestfs_inspect_get_mountpoints (g, root);
    if (mountpoints == NULL)
      exit (EXIT_FAILURE);

    qsort (mountpoints, count_strings (mountpoints) / 2, 2 * sizeof (char *),
           compare_keys_len);
    for (i = 0; mountpoints[i] != NULL; i += 2) {
      /* Ignore failures from this call, since bogus entries can
       * appear in the guest's /etc/fstab.
       */
      guestfs_mount_ro (g, mountpoints[i+1], mountpoints[i]);
      free (mountpoints[i]);
      free (mountpoints[i+1]);
    }
    free (mountpoints);

    /* If /etc/issue.net file exists, print up to 3 lines. */
    if (guestfs_is_file (g, "/etc/issue.net") > 0) {
      printf ("--- /etc/issue.net ---\n");
      lines = guestfs_head_n (g, 3, "/etc/issue.net");
      if (lines == NULL)
        exit (EXIT_FAILURE);
      for (i = 0; lines[i] != NULL; ++i) {
        printf ("%s\n", lines[i]);
        free (lines[i]);
      }
      free (lines);
    }

    /* Unmount everything. */
    if (guestfs_umount_all (g) == -1)
      exit (EXIT_FAILURE);

    free (root);
  }
  free (roots);

  guestfs_close (g);

  exit (EXIT_SUCCESS);
}