[Libguestfs] [PATCH V3] virt-diff: add new virt-diff tool
Richard W.M. Jones
rjones at redhat.com
Tue Aug 21 06:44:08 UTC 2012
On Mon, Aug 20, 2012 at 04:22:23PM +0800, Wanlong Gao wrote:
> add new virt-diff tool
>
> Signed-off-by: Wanlong Gao <gaowanlong at cn.fujitsu.com>
> ---
> cat/Makefile.am | 20 ++-
> cat/virt-diff.c | 525 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> po/POTFILES | 1 +
> 3 files changed, 545 insertions(+), 1 deletion(-)
> create mode 100644 cat/virt-diff.c
>
> diff --git a/cat/Makefile.am b/cat/Makefile.am
> index f7c763a..5f6a986 100644
> --- a/cat/Makefile.am
> +++ b/cat/Makefile.am
> @@ -27,7 +27,7 @@ EXTRA_DIST = \
>
> CLEANFILES = stamp-virt-cat.pod stamp-virt-ls.pod stamp-virt-filesystems.pod
This program has to have a manual page.
[...]
> +const char *libvirt_uri = NULL;
> +
> +static inline char *
> +diff_bad_case (char const *s)
> +{
> + return (char *) s;
> +}
> +
> +static void __attribute__((noreturn))
> +diff_usage (int status)
> +{
> + if (status != EXIT_SUCCESS) {
> + fprintf (stderr, _("Try `%s --help' for more information.\n"),
> + program_name);
> + } else {
> + fprintf (stdout,
> + _("%s: Show the differences between seed Guest and the others\n"
> + "Copyright (C) 2012 Fujitsu Limited.\n"
> + "Copyright (C) 2012 Red Hat Inc.\n"
> + "Usage:\n"
> + " %s [--options] -s domname -d domname path\n"
> + "Options:\n"
> + " -c|--connect uri Specify libvirt URI for -s and -d options\n"
> + " -s|--seed guest Add seed disk from libvirt guest\n"
> + " -d|--domain guest Add target disk from libvirt guest\n"
> + " --keys-from-stdin Read passphrases from stdin\n"
> + " --echo-keys Don't turn off echo for passphrases\n"
> + " --help Display brief help\n"),
> + program_name, program_name);
> + }
> + exit (status);
> +}
> +
> +/* Make a LUKS map name from the partition name,
> + * eg "/dev/vda2" => "luksvda2"
> + */
> +static void
> +diff_make_mapname (const char *device, char *mapname, size_t len)
> +{
> + size_t i = 0;
> +
> + if (len < 5)
> + abort ();
> + strcpy (mapname, "luks");
> + mapname += 4;
> + len -= 4;
> +
> + if (STRPREFIX (device, "/dev/"))
> + i = 5;
> +
> + for (; device[i] != '\0' && len >= 1; ++i) {
> + if (c_isalnum (device[i])) {
> + *mapname++ = device[i];
> + len--;
> + }
> + }
> +
> + *mapname = '\0';
> +}
> +
> +static void
> +free_strings (char **strings)
> +{
> + size_t i;
> +
> + for (i = 0; strings[i] != NULL; ++i)
> + free (strings[i]);
> + free (strings);
> +}
> +
> +static size_t
> +count_strings (char **strings)
> +{
> + size_t i;
> +
> + for (i = 0; strings[i] != NULL; ++i)
> + ;
> + return i;
> +}
> +
> +/* Simple implementation of decryption: look for any crypto_LUKS
> + * partitions and decrypt them, then rescan for VGs. This only works
> + * for Fedora whole-disk encryption. WIP to make this work for other
> + * encryption schemes.
> + */
> +static void
> +diff_inspect_do_decrypt (guestfs_h *g)
> +{
> + char **partitions = guestfs_list_partitions (g);
> + if (partitions == NULL)
> + exit (EXIT_FAILURE);
> +
> + int need_rescan = 0;
> + size_t i;
> + for (i = 0; partitions[i] != NULL; ++i) {
> + char *type = guestfs_vfs_type (g, partitions[i]);
> + if (type && STREQ (type, "crypto_LUKS")) {
> + char mapname[32];
> + diff_make_mapname (partitions[i], mapname, sizeof mapname);
> +
> + char *key = read_key (partitions[i]);
> + /* XXX Should we call guestfs_luks_open_ro if readonly flag
> + * is set? This might break 'mount_ro'.
> + */
> + if (guestfs_luks_open (g, partitions[i], key, mapname) == -1)
> + exit (EXIT_FAILURE);
> +
> + free (key);
> +
> + need_rescan = 1;
> + }
> + free (type);
> + }
> +
> + free_strings (partitions);
> +
> + if (need_rescan) {
> + if (guestfs_vgscan (g) == -1)
> + exit (EXIT_FAILURE);
> + if (guestfs_vg_activate_all (g, 1) == -1)
> + exit (EXIT_FAILURE);
> + }
> +}
> +
> +static int
> +compare_keys (const void *p1, const void *p2)
> +{
> + const char *key1 = * (char * const *) p1;
> + const char *key2 = * (char * const *) p2;
> +
> + return strcmp (key1, key2);
> +}
> +
> +static int
> +compare_keys_len (const void *p1, const void *p2)
> +{
> + const char *key1 = * (char * const *) p1;
> + const char *key2 = * (char * const *) p2;
> + int c;
> +
> + c = strlen (key1) - strlen (key2);
> + if (c != 0)
> + return c;
> +
> + return compare_keys (p1, p2);
> +}
> +
> +static void
> +diff_inspect_mount_root (guestfs_h *g, const char *root)
> +{
> + char **mountpoints = guestfs_inspect_get_mountpoints (g, root);
> + if (mountpoints == NULL)
> + exit (EXIT_FAILURE);
> +
> + /* Sort by key length, shortest key first, so that we end up
> + * mounting the filesystems in the correct order.
> + */
> + qsort (mountpoints, count_strings (mountpoints) / 2, 2 * sizeof (char *),
> + compare_keys_len);
> +
> + size_t i;
> + size_t mount_errors = 0;
> + for (i = 0; mountpoints[i] != NULL; i += 2) {
> + int r;
> + r = guestfs_mount_ro (g, mountpoints[i+1], mountpoints[i]);
> + if (r == -1) {
> + /* If the "/" filesystem could not be mounted, give up, else
> + * just count the errors and print a warning.
> + */
> + if (STREQ (mountpoints[i], "/"))
> + exit (EXIT_FAILURE);
> + mount_errors++;
> + }
> + }
> +
> + free_strings (mountpoints);
> +
> + if (mount_errors)
> + fprintf (stderr, _("%s: some filesystems could not be mounted (ignored)\n"),
> + program_name);
> +}
> +
> +/* This function implements the -i option. */
> +static void
> +diff_inspect_mount (guestfs_h *g)
> +{
> + const char *root = NULL;
> + diff_inspect_do_decrypt (g);
> +
> + char **roots = guestfs_inspect_os (g);
> + if (roots == NULL)
> + exit (EXIT_FAILURE);
> +
> + if (roots[0] == NULL) {
> + fprintf (stderr,
> + _("%s: no operating system was found on this disk\n"
> + "\n"
> + "If using guestfish '-i' option, remove this option and instead\n"
> + "use the commands 'run' followed by 'list-filesystems'.\n"
> + "You can then mount filesystems you want by hand using the\n"
> + "'mount' or 'mount-ro' command.\n"
> + "\n"
> + "If using guestmount '-i', remove this option and choose the\n"
> + "filesystem(s) you want to see by manually adding '-m' option(s).\n"
> + "Use 'virt-filesystems' to see what filesystems are available.\n"
> + "\n"
> + "If using other virt tools, this disk image won't work\n"
> + "with these tools. Use the guestfish equivalent commands\n"
> + "(see the virt tool manual page).\n"),
> + program_name);
> + free_strings (roots);
> + exit (EXIT_FAILURE);
> + }
This long generic text copied from guestfish isn't appropriate.
Just reduce it to the first line ("no operating system was found ...").
> + if (roots[1] != NULL) {
> + fprintf (stderr,
> + _("%s: multi-boot operating systems are not supported\n"
> + "\n"
> + "If using guestfish '-i' option, remove this option and instead\n"
> + "use the commands 'run' followed by 'list-filesystems'.\n"
> + "You can then mount filesystems you want by hand using the\n"
> + "'mount' or 'mount-ro' command.\n"
> + "\n"
> + "If using guestmount '-i', remove this option and choose the\n"
> + "filesystem(s) you want to see by manually adding '-m' option(s).\n"
> + "Use 'virt-filesystems' to see what filesystems are available.\n"
> + "\n"
> + "If using other virt tools, multi-boot operating systems won't work\n"
> + "with these tools. Use the guestfish equivalent commands\n"
> + "(see the virt tool manual page).\n"),
> + program_name);
> + free_strings (roots);
> + exit (EXIT_FAILURE);
> + }
And the same here.
> + root = roots[0];
> + free (roots);
> +
> + diff_inspect_mount_root (g, root);
> +}
> +
> +static void
> +free_drive (struct drv *drv)
> +{
> + if (!drv) return;
> +
> + free (drv->device);
> + free (drv);
> +}
> +
> +int
> +main (int argc, char *argv[])
> +{
> + /* set global program name that is not polluted with libtool artifacts. */
> + set_program_name (argv[0]);
> + bindtextdomain (PACKAGE, LOCALEBASEDIR);
> + textdomain (PACKAGE);
> +
> + enum { HELP_OPTION = CHAR_MAX + 1 };
> +
> + static const char *options = "s:d:";
> + static const struct option long_options[] = {
> + {"seed", 1, 0, 's'},
> + {"domain", 1, 0, 'd'},
> + {"help", 0, 0, HELP_OPTION},
> + {0, 0, 0, 0}
> + };
Lots of long options have disappeared here, eg. "keys-from-stdin" ...
> + struct drv *sdrv = NULL;
> + struct drv *ddrv = NULL;
> + int c, nr;
> + int option_index;
> + int spid, dpid;
> +
> + sg = guestfs_create ();
> + if (sg == NULL) {
> + fprintf (stderr, _("guestfs_create: failed to create seed handle\n"));
> + exit (EXIT_FAILURE);
> + }
> +
> + dg = guestfs_create ();
> + if (dg == NULL) {
> + fprintf (stderr, _("guestfs_create: failed to create comparison handle\n"));
> + exit (EXIT_FAILURE);
> + }
> +
> + argv[0] = diff_bad_case (program_name);
> +
> + for (;;) {
> + c = getopt_long (argc, argv, options, long_options, &option_index);
> + if (c == -1) break;
> +
> + switch (c) {
> + case 0:
> + if (STREQ (long_options[option_index].name, "keys-from-stdin")) {
> + keys_from_stdin = 1;
> + } else if (STREQ (long_options[option_index].name, "echo-keys")) {
> + echo_keys = 1;
> + } else if (STREQ (long_options[option_index].name, "seed")) {
> + if (sdrv) {
> + fprintf(stderr, _("Only one seed device"));
Missing program_name and \n (but see below).
> + exit (EXIT_FAILURE);
> + }
> + sdrv = calloc (1, sizeof (struct drv));
> + if (!sdrv) {
> + perror ("malloc");
> + exit (EXIT_FAILURE);
> + }
> + sdrv->type = drv_d;
> + sdrv->nr_drives = -1;
> + sdrv->d.guest = optarg;
> + sdrv->next = NULL;
> + } else if (STREQ (long_options[option_index].name, "domain")) {
> + if (ddrv) {
> + fprintf (stderr, _("Only one diff device"));
> + exit (EXIT_FAILURE);
> + }
> + ddrv = calloc (1, sizeof (struct drv));
> + if (!ddrv) {
> + perror ("malloc");
> + exit (EXIT_FAILURE);
> + }
> + ddrv->type = drv_d;
> + ddrv->nr_drives = -1;
> + ddrv->d.guest = optarg;
> + ddrv->next = NULL;
This code will never be used. When getopt_long has an equivalent
short option, it'll use that instead.
> + } else {
> + fprintf (stderr, _("%s: unknown long option: %s (%d)\n"),
> + program_name, long_options[option_index].name, option_index);
> + exit (EXIT_FAILURE);
> + }
> + break;
> +
> + case 'c':
> + libvirt_uri = optarg;
Missing 'break'.
> + case 's':
> + if (sdrv) {
> + fprintf(stderr, _("Only one seed device"));
> + exit (EXIT_FAILURE);
> + }
> + sdrv = calloc (1, sizeof (struct drv));
> + if (!sdrv) {
> + perror ("malloc");
> + exit (EXIT_FAILURE);
> + }
> + sdrv->type = drv_d;
> + sdrv->nr_drives = -1;
> + sdrv->d.guest = optarg;
> + sdrv->next = NULL;
> + break;
> +
> + case 'd':
> + if (ddrv) {
> + fprintf (stderr, _("Only one diff device"));
> + exit (EXIT_FAILURE);
> + }
> + ddrv = calloc (1, sizeof (struct drv));
> + if (!ddrv) {
> + perror ("malloc");
> + exit (EXIT_FAILURE);
> + }
> + ddrv->type = drv_d;
> + ddrv->nr_drives = -1;
> + ddrv->d.guest = optarg;
> + ddrv->next = NULL;
> + break;
The problem with this syntax is that it forces libvirt to be used. In
fact, you can only diff libvirt domains.
This seems problematic.
Why can't we use '-a' and '-d' options for one of the guests and some
other options (eg. '--sa' and '--sd') for the other one?
> + case HELP_OPTION:
> + diff_usage (EXIT_SUCCESS);
> +
> + default:
> + diff_usage (EXIT_FAILURE);
> + }
> + }
> +
> + if (sdrv == NULL)
> + diff_usage (EXIT_FAILURE);
> + if (ddrv == NULL)
> + diff_usage (EXIT_FAILURE);
> +
> + struct guestfs_add_domain_argv optargs = {
> + .bitmask = 0,
> + .libvirturi = libvirt_uri,
> + .readonly = 1,
> + .allowuuid = 1,
> + .readonlydisk = "read",
> + };
> + nr = guestfs_add_domain_argv (sg, sdrv->d.guest, &optargs);
> + if (nr == -1)
> + exit (EXIT_FAILURE);
> + sdrv->nr_drives = nr;
> + nr = guestfs_add_domain_argv (dg, ddrv->d.guest, &optargs);
> + if (nr == -1)
> + exit (EXIT_FAILURE);
> + ddrv->nr_drives = nr;
> +
> + if (guestfs_launch (sg) == -1)
> + exit (EXIT_FAILURE);
> + if (guestfs_launch (dg) == -1)
> + exit (EXIT_FAILURE);
> +
> + diff_inspect_mount (sg);
> + diff_inspect_mount (dg);
> +
> + char stempdir[] = "/tmp/sGuestXXXXXX";
> + char dtempdir[] = "/tmp/dGuestXXXXXX";
> +
> + if (mkdtemp (stempdir) == NULL) {
> + perror ("mkdtemp");
> + exit (EXIT_FAILURE);
> + }
> + if (mkdtemp (dtempdir) == NULL) {
> + perror ("mkdtemp");
> + exit (EXIT_FAILURE);
> + }
> +
> + if (guestfs_mount_local (sg, stempdir, -1) == -1)
> + exit (EXIT_FAILURE);
> + if (guestfs_mount_local (dg, dtempdir, -1) == -1)
> + exit (EXIT_FAILURE);
> +
> + spid = fork ();
> + if (spid == -1) {
> + perror ("fork");
> + exit (EXIT_FAILURE);
> + }
> + if (spid == 0) {
> + if (guestfs_mount_local_run (sg) == -1)
> + exit (EXIT_FAILURE);
> + _exit (EXIT_SUCCESS);
> + }
> +
> + dpid = fork();
> + if (dpid == -1) {
> + perror ("fork");
> + exit (EXIT_FAILURE);
> + }
> + if (dpid == 0) {
> + if (guestfs_mount_local_run (dg) == -1)
> + exit (EXIT_FAILURE);
> + _exit (EXIT_SUCCESS);
> + }
> +
> + const char *dir = argv[optind];
> + char system_arg[BUFSIZ];
> + sprintf (system_arg, "diff -urN %s%s %s%s", stempdir, dir,
> + dtempdir, dir);
> + sleep (5);
?
> + if (system (system_arg) == -1)
> + exit (EXIT_FAILURE);
> +
> + guestfs_umount_local (sg, GUESTFS_UMOUNT_LOCAL_RETRY, 1, -1);
> + waitpid (spid, NULL, 0);
> + guestfs_umount_local (dg, GUESTFS_UMOUNT_LOCAL_RETRY, 1, -1);
> + waitpid (dpid, NULL, 0);
You must check the return value of every call.
Also you should remove the temporary directories.
> + if (guestfs_shutdown (sg) == -1)
> + exit (EXIT_FAILURE);
> + if (guestfs_shutdown (dg) == -1)
> + exit (EXIT_FAILURE);
> +
> + free_drive (sdrv);
> + free_drive (ddrv);
> +
> + guestfs_close (sg);
> + guestfs_close (dg);
> +
> + exit (EXIT_SUCCESS);
> +}
> diff --git a/po/POTFILES b/po/POTFILES
> index 60887dc..ad58555 100644
> --- a/po/POTFILES
> +++ b/po/POTFILES
> @@ -1,6 +1,7 @@
> align/domains.c
> align/scan.c
> cat/virt-cat.c
> +cat/virt-diff.c
> cat/virt-filesystems.c
> cat/virt-ls.c
> daemon/9p.c
> --
> 1.7.12
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
libguestfs lets you edit virtual machines. Supports shell scripting,
bindings from many languages. http://libguestfs.org
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