On Tue, Jun 19, 2012 at 05:24:26PM +0800, Wanlong Gao wrote:
> add new virt-diff tool
>
> Signed-off-by: Wanlong Gao <gaowanl...@cn.fujitsu.com>
> ---
>
> Hi Rich,
> This just a thought of virt-diff tool, I send it out ASAP
> to ask your opinions.
>
> Now, I just implement two guest, one SEED guest and one
> DIFF guest, and the patch is wholly untested.
> Please take patient to review.
> And it's hard for me to start two guest handler, if you
> have time, please help or just handle this work.
>
> PS, I attended the LinuxCon Japan this month, so the plan
> delayed.
The outline of the code seems to be:
* create two handles
* add both disks
* inspect both disks
* mount-local both disks on separate temporary directories
* run regular 'diff' command across the temporary directories
These is a reasonable approach for code simplicity, but I guess it'll
be very slow in practice.
> cat/virt-diff.c | 423
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 423 insertions(+)
> create mode 100644 cat/virt-diff.c
>
> diff --git a/cat/virt-diff.c b/cat/virt-diff.c
> new file mode 100644
> index 0000000..4bd8730
> --- /dev/null
> +++ b/cat/virt-diff.c
> @@ -0,0 +1,423 @@
> +/* virt-diff
> + * Copyright (C) 2012 FUJITSU LIMITED.
> + * Copyright (C) 2010-2012 Red Hat Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
> USA.
> + */
> +
> +#include <config.h>
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <inttypes.h>
> +#include <unistd.h>
> +#include <getopt.h>
> +#include <fcntl.h>
> +#include <locale.h>
> +#include <assert.h>
> +#include <time.h>
> +#include <libintl.h>
> +
> +#include "human.h"
> +#include "progname.h"
> +
> +#include "guestfs.h"
> +#include "options.h"
> +
> +#ifndef O_CLOEXEC
> +#define O_CLOEXEC 0
> +#endif
> +
> +/* libguestfs handle for seed. */
> +static guestfs_h *sg;
> +
> +/* libguestfs handle for temp. */
> +static guestfs_h *g;
> +
> +static int live = 0;
> +static int verbose = 0;
> +static int keys_from_stdin = 0;
> +static int echo_keys = 0;
> +static const char *libvirt_uri = NULL;
> +static int inspector = 1;
> +
> +static doing_diff = 1;
> +
> +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) 2010-2012 Red Hat Inc.\n"
> + "Usage:\n"
> + "\n"
> + "\n"
> + "Options:\n"
> + " -a|--add image Add image\n"
> + " --checksum[=...] Display file checksums\n"),
> + program_name);
> + }
> + exit (status);
> +}
> +
> +
> +/* 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];
> + 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 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)
> +{
> + 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);
> + }
> +
> + 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);
> + }
> +
> + root = roots[0];
> + free (roots);
> +
> + diff_inspect_mount_root (root);
> +}
> +
> +int
> +main (int argc, int *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'},
> + {0, 0, 0, 0}
> + };
Eventually you'll need to support all the other options too, or
at least --help.
> + struct drv *sdrv = NULL;
> + struct drv *drv = NULL;
> + int c;
> +
> + sg = guestfs_create ();
> + if (sg == NULL) {
> + fprintf (stderr, _("guestfs_create: failed to create seed handle\n"));
> + exit (EXIT_FAILURE);
> + }
> +
> + g = guestfs_create ();
> + if (g == NULL) {
> + fprintf (stderr, _("guestfs_create: failed to create comparison
> handle\n"));
> + exit (EXIT_FAILURE);
> + }
> +
> + argv[0] = 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, "seed")) {
> + if (sdrv) {
> + fprintf(stderr, _("...."));
> + 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")) {
> + drv = calloc ("malloc");
> + if (!drv) {
> + perror ("malloc");
> + exit (EXIT_FAILURE);
> + }
> + drv->type = drv_d;
> + drv->nr_drives = -1;
> + drv->d.guest = optarg;
> + drv->next = NULL;
> + } else {
> + fprintf (stderr, _("%s: unknown long option: %s (%d)\n"),
> + program_name, long_options[option_index].name,
> option_index);
> + exit (EXIT_FAILURE);
> + }
> + break;
> +
> + case 'd':
> + OPTION_d;
> + break;
> +
> + case 's':
> + if (sdrv) {
> + fprintf(stderr, _("...."));
> + 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 HELP_OPTION:
> + usage (EXIT_SUCCESS);
> +
> + default:
> + usage (EXIT_FAILURE);
> + }
> + }
> +
> + if (sdrv == NULL)
> + usage (EXIT_FAILURE);
> + if (drv == NULL)
> + usage (EXIT_FAILURE);
> +
> + struct guestfs_add_domain_argv optargs = {
> + .bitmask = 0;
> + .libvirturi = NULL;
> + .readonly = 1;
> + .allowuuid = 1;
> + .readonlydisk = "read";
> + };
> + nr = guestfs_add_domain_argv (sg, sdrv->d.guest, &optargs);
> + if (r == -1)
> + exit (EXIT_FAILURE);
> + sdrv->nr_drives = nr;
> + nr = guestfs_add_domain_argv (g, drv->d.guest, &optargs);
> + if (r == -1)
> + exit (EXIT_FAILURE);
> + drv->nr_drives = nr;
> +
> + if (guestfs_launch (sg) == -1)
> + exit (EXIT_FAILURE);
> + if (guestfs_launch (g) == -1)
> + exit (EXIT_FAILURE);
> +
> + diff_inspect_mount (sg);
> + diff_inspect_mount (g);
> +
> + char stempdir = "/tmp/sGuestXXXXXX";
> + char tempdir = "/tmp/GuestXXXXXX";
> + char sdir[256];
> + char dir[256];
> +
> + if (mkdtemp (stempdir) == NULL) {
> + perror ("mkdtemp");
> + exit (EXIT_FAILURE);
> + }
> + if (mkdtemp (tempdir) == NULL) {
> + perror ("mkdtemp");
> + exit (EXIT_FAILURE);
> + }
> +
> + if (guestfs_mount_local (sg, stempdir, -1) == -1)
> + exit (EXIT_FAILURE);
> + if (guestfs_mount_local (g, tempdir, -1) == -1)
> + exit (EXIT_FAILURE);
> +
> + spid = fork ();
> + if (spid == -1) {
> + perror ("fork");
> + exit (EXIT_FAILURE);
> + }
> + if (spid == 0) {
> + while (doing_diff)
> + sleep (1);
> + guestfs_umount_local (sg, GUESTFS_UMOUNT_LOCAL_RETRY, 1, -1);
> + _exit (EXIT_SUCCESS);
> + }
> +
> + pid = fork();
> + if (pid == -1) {
> + perror ("fork");
> + exit (EXIT_FAILURE);
> + }
> + if (pid == 0) {
> + while (doing_diff)
> + sleep (1);
> + guestfs_umount_local (g, GUESTFS_UMOUNT_LOCAL_RETRY, 1, -1);
> + _exit (EXIT_SUCCESS);
> + }
The doing_diff variable isn't shared between forked processes, so the
child processes will simply busy-wait forever. In any case the main
program never even sets doing_diff.
This code is going to be far more complex in the final version.
> + if (guestfs_mount_local_run (sg) == -1)
> + exit (EXIT_FAILURE);
> + if (guestfs_mount_local_run (g) == -1)
> + exit (EXIT_FAILURE);
> +
> + const char *dir = argv[optind];
> + char system_arg[BUFSIZ];
> + sprintf (system_arg, "diff -urN %s%s %s%s", stempdir, dir,
> + tempdir, dir);
> + system(system_arg);
> +
> + waitpid (spid, NULL, 0);
> + waitpid (pid, NULL, 0);
> +
> + if (guestfs_umount (sg, "/") == -1)
> + exit (EXIT_FAILURE);
> + if (guestfs_umount (g, "/") == -1)
> + exit (EXIT_FAILURE);
> +
> + free_drives (sdrvs);
> + free_drives (drv);
> +
> + guestfs_close (sg);
> + guestfs_close (g);
> +
> + exit (EXIT_SUCCESS);
> +}
> --
> 1.7.11.rc0
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-top is 'top' for virtual machines. Tiny program with many
powerful monitoring features, net stats, disk stats, logging, etc.
http://et.redhat.com/~rjones/virt-top
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