--- /dev/null
+/* This is a more significant example of a tool which can grab the
+ * DHCP address from some types of virtual machine. Since there are
+ * so many possible ways to do this, without clarity on which is the
+ * best way, I don't want to make this into an official virt tool.
+ *
+ * For more information, see:
+ *
+ * https://rwmj.wordpress.com/2010/10/26/tip-find-the-ip-address-of-a-virtual-machine/
+ * https://rwmj.wordpress.com/2011/03/30/tip-another-way-to-get-the-ip-address-of-a-virtual-machine/
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <assert.h>
+
+#include <guestfs.h>
+#include <hivex.h>
+
+static int compare_keys_len (const void *p1, const void *p2);
+static size_t count_strings (char *const *argv);
+static void free_strings (char **argv);
+static void mount_disks (guestfs_h *g, char *root);
+static void print_dhcp_address (guestfs_h *g, char *root);
+static void print_dhcp_address_linux (guestfs_h *g, char *root, const char *logfile);
+static void print_dhcp_address_windows (guestfs_h *g, char *root);
+
+int
+main (int argc, char *argv[])
+{
+ guestfs_h *g;
+ size_t i;
+ char **roots, *root;
+
+ if (argc < 2) {
+ fprintf (stderr,
+ "Usage: virt-dhcp-address disk.img [disk.img [...]]\n"
+ "Note that all disks must come from a single virtual machine.\n");
+ exit (EXIT_FAILURE);
+ }
+
+ g = guestfs_create ();
+ if (g == NULL) {
+ perror ("failed to create libguestfs handle");
+ exit (EXIT_FAILURE);
+ }
+
+ for (i = 1; i < (size_t) argc; ++i) {
+ /* Attach the disk image(s) read-only to libguestfs. */
+ if (guestfs_add_drive_opts (g, argv[i],
+ /* 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, "virt-dhcp-address: no operating systems found\n");
+ exit (EXIT_FAILURE);
+ }
+ if (count_strings (roots) > 1) {
+ fprintf (stderr, "virt-dhcp-address: multi-boot operating system\n");
+ exit (EXIT_FAILURE);
+ }
+
+ root = roots[0];
+
+ /* Mount up the guest's disks. */
+ mount_disks (g, root);
+
+ /* Print DHCP address. */
+ print_dhcp_address (g, root);
+
+ /* Close handle and exit. */
+ guestfs_close (g);
+ free_strings (roots);
+
+ exit (EXIT_SUCCESS);
+}
+
+static void
+mount_disks (guestfs_h *g, char *root)
+{
+ char **mountpoints;
+ size_t i;
+
+ /* 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_strings (mountpoints);
+}
+
+static void
+print_dhcp_address (guestfs_h *g, char *root)
+{
+ char *guest_type, *guest_distro;
+
+ /* Depending on the guest type, try to get the DHCP address. */
+ guest_type = guestfs_inspect_get_type (g, root);
+
+ if (strcmp (guest_type, "linux") == 0) {
+ guest_distro = guestfs_inspect_get_distro (g, root);
+
+ if (strcmp (guest_distro, "fedora") == 0 ||
+ strcmp (guest_distro, "rhel") == 0 ||
+ strcmp (guest_distro, "redhat-based") == 0) {
+ print_dhcp_address_linux (g, root, "/var/log/messages");
+ }
+ else if (strcmp (guest_distro, "debian") == 0 ||
+ strcmp (guest_distro, "ubuntu") == 0) {
+ print_dhcp_address_linux (g, root, "/var/log/syslog");
+ }
+ else {
+ fprintf (stderr, "virt-dhcp-address: don't know how to get DHCP address from '%s'\n",
+ guest_distro);
+ exit (EXIT_FAILURE);
+ }
+
+ free (guest_distro);
+ }
+ else if (strcmp (guest_type, "windows") == 0) {
+ print_dhcp_address_windows (g, root);
+ }
+ else {
+ fprintf (stderr, "virt-dhcp-address: don't know how to get DHCP address from '%s'\n",
+ guest_type);
+ exit (EXIT_FAILURE);
+ }
+
+ free (guest_type);
+}
+
+/* Look for dhclient messages in logfile.
+ */
+static void
+print_dhcp_address_linux (guestfs_h *g, char *root, const char *logfile)
+{
+ char **lines, *p;
+ size_t len;
+
+ lines = guestfs_egrep (g, "dhclient.*: bound to ", logfile);
+ if (lines == NULL)
+ exit (EXIT_FAILURE);
+
+ len = count_strings (lines);
+ if (len == 0) {
+ fprintf (stderr, "virt-dhcp-address: cannot find DHCP address for this guest.\n");
+ exit (EXIT_FAILURE);
+ }
+
+ /* Only want the last message. */
+ p = strstr (lines[len-1], "bound to ");
+ assert (p);
+ p += 9;
+ len = strcspn (p, " ");
+ p[len] = '\0';
+
+ printf ("%s\n", p);
+
+ free_strings (lines);
+}
+
+/* Download the Windows SYSTEM hive and find DHCP configuration in there. */
+static void
+print_dhcp_address_windows (guestfs_h *g, char *root_unused)
+{
+ char *system_path;
+ char tmpfile[] = "/tmp/systemXXXXXX";
+ int fd, err;
+ hive_h *h;
+ hive_node_h root, node, *nodes;
+ hive_value_h value;
+ int32_t dword;
+ char controlset[] = "ControlSetXXX";
+ size_t i;
+ char *p;
+
+ /* Locate the SYSTEM hive case-sensitive path. */
+ system_path =
+ guestfs_case_sensitive_path (g, "/windows/system32/config/system");
+ if (!system_path) {
+ fprintf (stderr, "virt-dhcp-address: HKLM\\System not found in this guest.");
+ exit (EXIT_FAILURE);
+ }
+
+ fd = mkstemp (tmpfile);
+ if (fd == -1) {
+ perror ("mkstemp");
+ exit (EXIT_FAILURE);
+ }
+
+ /* Download the SYSTEM hive. */
+ if (guestfs_download (g, system_path, tmpfile) == -1)
+ exit (EXIT_FAILURE);
+
+ free (system_path);
+
+ /* Open the hive to parse it. */
+ h = hivex_open (tmpfile, 0);
+ err = errno;
+ close (fd);
+ unlink (tmpfile);
+
+ if (h == NULL) {
+ errno = err;
+ perror ("hivex_open");
+ exit (EXIT_FAILURE);
+ }
+
+ /* Navigate to the Select key so we know which ControlSet is in use. */
+ root = hivex_root (h);
+ if (root == 0) {
+ perror ("hivex_root");
+ exit (EXIT_FAILURE);
+ }
+ node = hivex_node_get_child (h, root, "Select");
+ if (node == 0) {
+ if (errno != 0)
+ perror ("hivex_node_get_child");
+ else
+ fprintf (stderr, "virt-dhcp-address: HKLM\\System\\Select key not found.");
+ exit (EXIT_FAILURE);
+ }
+ value = hivex_node_get_value (h, node, "Current");
+ if (value == 0) {
+ if (errno != 0)
+ perror ("hivex_node_get_value");
+ else
+ fprintf (stderr, "virt-dhcp-address: HKLM\\System\\Select Default entry not found.");
+ exit (EXIT_FAILURE);
+ }
+ /* XXX Should check the type. */
+ dword = hivex_value_dword (h, value);
+ snprintf (controlset, sizeof controlset, "ControlSet%03d", dword);
+
+ /* Get ControlSetXXX\Services\Tcpip\Parameters\Interfaces. */
+ const char *path[] = { controlset, "Services", "Tcpip", "Parameters",
+ "Interfaces" };
+ node = root;
+ errno = 0;
+ for (i = 0; node != 0 && i < sizeof path / sizeof path[0]; ++i)
+ node = hivex_node_get_child (h, node, path[i]);
+
+ if (node == 0) {
+ if (errno != 0)
+ perror ("hivex_node_get_child");
+ else
+ fprintf (stderr, "virt-dhcp-address: HKLM\\System\\%s\\Services\\Tcpip\\Parameters\\Interfaces not found.", controlset);
+ exit (EXIT_FAILURE);
+ }
+
+ /* Look for a node under here which has a "DhcpIPAddress" entry in it. */
+ nodes = hivex_node_children (h, node);
+ if (nodes == NULL) {
+ perror ("hivex_node_children");
+ exit (EXIT_FAILURE);
+ }
+
+ value = 0;
+ for (i = 0; value == 0 && nodes[i] != 0; ++i) {
+ errno = 0;
+ value = hivex_node_get_value (h, nodes[i], "DhcpIPAddress");
+ if (value == 0 && errno != 0) {
+ perror ("hivex_node_get_value");
+ exit (EXIT_FAILURE);
+ }
+ }
+
+ if (value == 0) {
+ fprintf (stderr, "virt-dhcp-address: cannot find DHCP address for this guest.\n");
+ exit (EXIT_FAILURE);
+ }
+
+ /* Get the string and use hivex's auto-conversion to convert it to UTF-8
+ * for output.
+ */
+ p = hivex_value_string (h, value);
+ if (!p) {
+ perror ("hivex_value_string");
+ exit (EXIT_FAILURE);
+ }
+
+ printf ("%s\n", p);
+
+ /* Close the hive handle. */
+ hivex_close (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;
+}
+
+static void
+free_strings (char **argv)
+{
+ size_t i;
+
+ for (i = 0; argv[i]; ++i)
+ free (argv[i]);
+ free (argv);
+}
git.annexia.org / libguestfs.git / commitdiff