docs: Standard C examples, and guestfs-examples(3) man page.

[libguestfs.git] / examples / inspect_vm.c

diff --git a/examples/inspect_vm.c b/examples/inspect_vm.c
new file mode 100644 (file)
index 0000000..4019a01
--- /dev/null
+++ b/examples/inspect_vm.c
@@ -0,0 +1,132 @@
+#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 int
+count_strings (char *const *argv)
+{
+  int 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) {
+      if (guestfs_mount_ro (g, mountpoints[i+1], mountpoints[i]) == -1)
+        exit (EXIT_FAILURE);
+      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);
+}