/*
* e2undo.c - Replay an undo log onto an ext2/3/4 filesystem
*
* Copyright IBM Corporation, 2007
* Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*/
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#ifdef HAVE_GETOPT_H
#include <getopt.h>
#endif
#include <fcntl.h>
#if HAVE_ERRNO_H
#include <errno.h>
#endif
#include <unistd.h>
#include <libgen.h>
#include "ext2fs/ext2fs.h"
#include "support/nls-enable.h"
#undef DEBUG
#ifdef DEBUG
# define dbg_printf(f, a...) do {printf(f, ## a); fflush(stdout); } while (0)
#else
# define dbg_printf(f, a...)
#endif
/*
* Undo file format: The file is cut up into undo_header.block_size blocks.
* The first block contains the header.
* The second block contains the superblock.
* There is then a repeating series of blocks as follows:
* A key block, which contains undo_keys to map the following data blocks.
* Data blocks
* (Note that there are pointers to the first key block and the sb, so this
* order isn't strictly necessary.)
*/
#define E2UNDO_MAGIC "E2UNDO02"
#define KEYBLOCK_MAGIC 0xCADECADE
#define E2UNDO_STATE_FINISHED 0x1 /* undo file is complete */
#define E2UNDO_MIN_BLOCK_SIZE 1024 /* undo blocks are no less than 1KB */
#define E2UNDO_MAX_BLOCK_SIZE 1048576 /* undo blocks are no more than 1MB */
struct undo_header {
char magic[8]; /* "E2UNDO02" */
__le64 num_keys; /* how many keys? */
__le64 super_offset; /* where in the file is the superblock copy? */
__le64 key_offset; /* where do the key/data block chunks start? */
__le32 block_size; /* block size of the undo file */
__le32 fs_block_size; /* block size of the target device */
__le32 sb_crc; /* crc32c of the superblock */
__le32 state; /* e2undo state flags */
__le32 f_compat; /* compatible features (none so far) */
__le32 f_incompat; /* incompatible features (none so far) */
__le32 f_rocompat; /* ro compatible features (none so far) */
__le32 pad32; /* padding for fs_offset */
__le64 fs_offset; /* filesystem offset */
__u8 padding[436]; /* padding */
__le32 header_crc; /* crc32c of the header (but not this field) */
};
#define E2UNDO_MAX_EXTENT_BLOCKS 512 /* max extent size, in blocks */
struct undo_key {
__le64 fsblk; /* where in the fs does the block go */
__le32 blk_crc; /* crc32c of the block */
__le32 size; /* how many bytes in this block? */
};
struct undo_key_block {
__le32 magic; /* KEYBLOCK_MAGIC number */
__le32 crc; /* block checksum */
__le64 reserved; /* zero */
#if __GNUC_PREREQ (4, 8)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpedantic"
#endif
struct undo_key keys[0]; /* keys, which come immediately after */
#if __GNUC_PREREQ (4, 8)
#pragma GCC diagnostic pop
#endif
};
struct undo_key_info {
blk64_t fsblk;
blk64_t fileblk;
__u32 blk_crc;
unsigned int size;
};
struct undo_context {
struct undo_header hdr;
io_channel undo_file;
unsigned int blocksize, fs_blocksize;
blk64_t super_block;
size_t num_keys;
struct undo_key_info *keys;
};
#define KEYS_PER_BLOCK(d) (((d)->blocksize / sizeof(struct undo_key)) - 1)
#define E2UNDO_FEATURE_COMPAT_FS_OFFSET 0x1 /* the filesystem offset */
static inline int e2undo_has_feature_fs_offset(struct undo_header *header) {
return ext2fs_le32_to_cpu(header->f_compat) &
E2UNDO_FEATURE_COMPAT_FS_OFFSET;
}
static char *prg_name;
static char *undo_file;
static void usage(void)
{
fprintf(stderr,
_("Usage: %s [-f] [-h] [-n] [-o offset] [-v] [-z undo_file] <transaction file> <filesystem>\n"), prg_name);
exit(1);
}
static void dump_header(struct undo_header *hdr)
{
printf("nr keys:\t%llu\n", ext2fs_le64_to_cpu(hdr->num_keys));
printf("super block:\t%llu\n", ext2fs_le64_to_cpu(hdr->super_offset));
printf("key block:\t%llu\n", ext2fs_le64_to_cpu(hdr->key_offset));
printf("block size:\t%u\n", ext2fs_le32_to_cpu(hdr->block_size));
printf("fs block size:\t%u\n", ext2fs_le32_to_cpu(hdr->fs_block_size));
printf("super crc:\t0x%x\n", ext2fs_le32_to_cpu(hdr->sb_crc));
printf("state:\t\t0x%x\n", ext2fs_le32_to_cpu(hdr->state));
printf("compat:\t\t0x%x\n", ext2fs_le32_to_cpu(hdr->f_compat));
printf("incompat:\t0x%x\n", ext2fs_le32_to_cpu(hdr->f_incompat));
printf("rocompat:\t0x%x\n", ext2fs_le32_to_cpu(hdr->f_rocompat));
if (e2undo_has_feature_fs_offset(hdr))
printf("fs offset:\t%llu\n", ext2fs_le64_to_cpu(hdr->fs_offset));
printf("header crc:\t0x%x\n", ext2fs_le32_to_cpu(hdr->header_crc));
}
static void print_undo_mismatch(struct ext2_super_block *fs_super,
struct ext2_super_block *undo_super)
{
printf("%s",
_("The file system superblock doesn't match the undo file.\n"));
if (memcmp(fs_super->s_uuid, undo_super->s_uuid,
sizeof(fs_super->s_uuid)))
printf("%s", _("UUID does not match.\n"));
if (fs_super->s_mtime != undo_super->s_mtime)
printf("%s", _("Last mount time does not match.\n"));
if (fs_super->s_wtime != undo_super->s_wtime)
printf("%s", _("Last write time does not match.\n"));
if (fs_super->s_kbytes_written != undo_super->s_kbytes_written)
printf("%s", _("Lifetime write counter does not match.\n"));
}
static int check_filesystem(struct undo_context *ctx, io_channel channel)
{
struct ext2_super_block super, *sb;
char *buf;
__u32 sb_crc;
errcode_t retval;
io_channel_set_blksize(channel, SUPERBLOCK_OFFSET);
retval = io_channel_read_blk64(channel, 1, -SUPERBLOCK_SIZE, &super);
if (retval) {
com_err(prg_name, retval,
"%s", _("while reading filesystem superblock."));
return retval;
}
/*
* Compare the FS and the undo file superblock so that we can't apply
* e2undo "patches" out of order.
*/
retval = ext2fs_get_mem(ctx->blocksize, &buf);
if (retval) {
com_err(prg_name, retval, "%s", _("while allocating memory"));
return retval;
}
retval = io_channel_read_blk64(ctx->undo_file, ctx->super_block,
-SUPERBLOCK_SIZE, buf);
if (retval) {
com_err(prg_name, retval, "%s", _("while fetching superblock"));
goto out;
}
sb = (struct ext2_super_block *)buf;
sb->s_magic = ~sb->s_magic;
if (memcmp(&super, buf, sizeof(super))) {
print_undo_mismatch(&super, (struct ext2_super_block *)buf);
retval = -1;
goto out;
}
sb_crc = ext2fs_crc32c_le(~0, (unsigned char *)buf, SUPERBLOCK_SIZE);
if (ext2fs_le32_to_cpu(ctx->hdr.sb_crc) != sb_crc) {
fprintf(stderr,
_("Undo file superblock checksum doesn't match.\n"));
retval = -1;
goto out;
}
out:
ext2fs_free_mem(&buf);
return retval;
}
static int key_compare(const void *a, const void *b)
{
const struct undo_key_info *ka, *kb;
ka = a;
kb = b;
return ka->fsblk - kb->fsblk;
}
static int e2undo_setup_tdb(const char *name, io_manager *io_ptr)
{
errcode_t retval = 0;
const char *tdb_dir;
char *tdb_file = NULL;
char *dev_name, *tmp_name;
/* (re)open a specific undo file */
if (undo_file && undo_file[0] != 0) {
retval = set_undo_io_backing_manager(*io_ptr);
if (retval)
goto err;
*io_ptr = undo_io_manager;
retval = set_undo_io_backup_file(undo_file);
if (retval)
goto err;
printf(_("Overwriting existing filesystem; this can be undone "
"using the command:\n"
" e2undo %s %s\n\n"),
undo_file, name);
return retval;
}
/*
* Configuration via a conf file would be
* nice
*/
tdb_dir = getenv("E2FSPROGS_UNDO_DIR");
if (!tdb_dir)
tdb_dir = "/var/lib/e2fsprogs";
if (!strcmp(tdb_dir, "none") || (tdb_dir[0] == 0) ||
access(tdb_dir, W_OK))
return 0;
tmp_name = strdup(name);
if (!tmp_name)
goto errout;
dev_name = basename(tmp_name);
tdb_file = malloc(strlen(tdb_dir) + 8 + strlen(dev_name) + 7 + 1);
if (!tdb_file) {
free(tmp_name);
goto errout;
}
sprintf(tdb_file, "%s/e2undo-%s.e2undo", tdb_dir, dev_name);
free(tmp_name);
if ((unlink(tdb_file) < 0) && (errno != ENOENT)) {
retval = errno;
com_err(prg_name, retval,
_("while trying to delete %s"), tdb_file);
goto errout;
}
retval = set_undo_io_backing_manager(*io_ptr);
if (retval)
goto errout;
*io_ptr = undo_io_manager;
retval = set_undo_io_backup_file(tdb_file);
if (retval)
goto errout;
printf(_("Overwriting existing filesystem; this can be undone "
"using the command:\n"
" e2undo %s %s\n\n"),
tdb_file, name);
free(tdb_file);
return 0;
errout:
free(tdb_file);
err:
com_err(prg_name, retval, "while trying to setup undo file\n");
return retval;
}
int main(int argc, char *argv[])
{
int c, force = 0, dry_run = 0, verbose = 0, dump = 0;
io_channel channel;
errcode_t retval;
int mount_flags, csum_error = 0, io_error = 0;
size_t i, keys_per_block;
char *device_name, *tdb_file;
io_manager manager = unix_io_manager;
struct undo_context undo_ctx;
char *buf;
struct undo_key_block *keyb;
struct undo_key *dkey;
struct undo_key_info *ikey;
__u32 key_crc, blk_crc, hdr_crc;
blk64_t lblk;
ext2_filsys fs;
__u64 offset = 0;
char opt_offset_string[40] = { 0 };
#ifdef ENABLE_NLS
setlocale(LC_MESSAGES, "");
setlocale(LC_CTYPE, "");
bindtextdomain(NLS_CAT_NAME, LOCALEDIR);
textdomain(NLS_CAT_NAME);
set_com_err_gettext(gettext);
#endif
add_error_table(&et_ext2_error_table);
prg_name = argv[0];
while ((c = getopt(argc, argv, "fhno:vz:")) != EOF) {
switch (c) {
case 'f':
force = 1;
break;
case 'h':
dump = 1;
break;
case 'n':
dry_run = 1;
break;
case 'o':
offset = strtoull(optarg, &buf, 0);
if (*buf) {
com_err(prg_name, 0,
_("illegal offset - %s"), optarg);
exit(1);
}
/* used to indicate that an offset was specified */
opt_offset_string[0] = 1;
break;
case 'v':
verbose = 1;
break;
case 'z':
undo_file = optarg;
break;
default:
usage();
}
}
if (argc != optind + 2)
usage();
tdb_file = argv[optind];
device_name = argv[optind+1];
if (undo_file && strcmp(tdb_file, undo_file) == 0) {
printf(_("Will not write to an undo file while replaying it.\n"));
exit(1);
}
/* Interpret the undo file */
retval = manager->open(tdb_file, IO_FLAG_EXCLUSIVE,
&undo_ctx.undo_file);
if (retval) {
com_err(prg_name, errno,
_("while opening undo file `%s'\n"), tdb_file);
exit(1);
}
retval = io_channel_read_blk64(undo_ctx.undo_file, 0,
-(int)sizeof(undo_ctx.hdr),
&undo_ctx.hdr);
if (retval) {
com_err(prg_name, retval, _("while reading undo file"));
exit(1);
}
if (memcmp(undo_ctx.hdr.magic, E2UNDO_MAGIC,
sizeof(undo_ctx.hdr.magic))) {
fprintf(stderr, _("%s: Not an undo file.\n"), tdb_file);
exit(1);
}
if (dump) {
dump_header(&undo_ctx.hdr);
exit(1);
}
hdr_crc = ext2fs_crc32c_le(~0, (unsigned char *)&undo_ctx.hdr,
sizeof(struct undo_header) -
sizeof(__u32));
if (!force && ext2fs_le32_to_cpu(undo_ctx.hdr.header_crc) != hdr_crc) {
fprintf(stderr, _("%s: Header checksum doesn't match.\n"),
tdb_file);
exit(1);
}
undo_ctx.blocksize = ext2fs_le32_to_cpu(undo_ctx.hdr.block_size);
undo_ctx.fs_blocksize = ext2fs_le32_to_cpu(undo_ctx.hdr.fs_block_size);
if (undo_ctx.blocksize == 0 || undo_ctx.fs_blocksize == 0) {
fprintf(stderr, _("%s: Corrupt undo file header.\n"), tdb_file);
exit(1);
}
if (!force && undo_ctx.blocksize > E2UNDO_MAX_BLOCK_SIZE) {
fprintf(stderr, _("%s: Undo block size too large.\n"),
tdb_file);
exit(1);
}
if (!force && undo_ctx.blocksize < E2UNDO_MIN_BLOCK_SIZE) {
fprintf(stderr, _("%s: Undo block size too small.\n"),
tdb_file);
exit(1);
}
undo_ctx.super_block = ext2fs_le64_to_cpu(undo_ctx.hdr.super_offset);
undo_ctx.num_keys = ext2fs_le64_to_cpu(undo_ctx.hdr.num_keys);
io_channel_set_blksize(undo_ctx.undo_file, undo_ctx.blocksize);
/*
* Do not compare undo_ctx.hdr.f_compat with the available compatible
* features set, because a "missing" compatible feature should
* not cause any problems.
*/
if (!force && (undo_ctx.hdr.f_incompat || undo_ctx.hdr.f_rocompat)) {
fprintf(stderr, _("%s: Unknown undo file feature set.\n"),
tdb_file);
exit(1);
}
/* open the fs */
retval = ext2fs_check_if_mounted(device_name, &mount_flags);
if (retval) {
com_err(prg_name, retval, _("Error while determining whether "
"%s is mounted."), device_name);
exit(1);
}
if (mount_flags & EXT2_MF_MOUNTED) {
com_err(prg_name, retval, "%s", _("e2undo should only be run "
"on unmounted filesystems"));
exit(1);
}
if (undo_file) {
retval = e2undo_setup_tdb(device_name, &manager);
if (retval)
exit(1);
}
retval = manager->open(device_name,
IO_FLAG_EXCLUSIVE | (dry_run ? 0 : IO_FLAG_RW),
&channel);
if (retval) {
com_err(prg_name, retval,
_("while opening `%s'"), device_name);
exit(1);
}
if (*opt_offset_string || e2undo_has_feature_fs_offset(&undo_ctx.hdr)) {
if (!*opt_offset_string)
offset = ext2fs_le64_to_cpu(undo_ctx.hdr.fs_offset);
retval = snprintf(opt_offset_string, sizeof(opt_offset_string),
"offset=%llu", offset);
if ((size_t) retval >= sizeof(opt_offset_string)) {
/* should not happen... */
com_err(prg_name, 0, _("specified offset is too large"));
exit(1);
}
io_channel_set_options(channel, opt_offset_string);
}
if (!force && check_filesystem(&undo_ctx, channel))
exit(1);
/* prepare to read keys */
retval = ext2fs_get_mem(sizeof(struct undo_key_info) * undo_ctx.num_keys,
&undo_ctx.keys);
if (retval) {
com_err(prg_name, retval, "%s", _("while allocating memory"));
exit(1);
}
ikey = undo_ctx.keys;
retval = ext2fs_get_mem(undo_ctx.blocksize, &keyb);
if (retval) {
com_err(prg_name, retval, "%s", _("while allocating memory"));
exit(1);
}
retval = ext2fs_get_mem(E2UNDO_MAX_EXTENT_BLOCKS * undo_ctx.blocksize,
&buf);
if (retval) {
com_err(prg_name, retval, "%s", _("while allocating memory"));
exit(1);
}
/* load keys */
keys_per_block = KEYS_PER_BLOCK(&undo_ctx);
lblk = ext2fs_le64_to_cpu(undo_ctx.hdr.key_offset);
dbg_printf("nr_keys=%lu, kpb=%zu, blksz=%u\n",
undo_ctx.num_keys, keys_per_block, undo_ctx.blocksize);
for (i = 0; i < undo_ctx.num_keys; i += keys_per_block) {
size_t j, max_j;
__le32 crc;
retval = io_channel_read_blk64(undo_ctx.undo_file,
lblk, 1, keyb);
if (retval) {
com_err(prg_name, retval, "%s", _("while reading keys"));
if (force) {
io_error = 1;
undo_ctx.num_keys = i - 1;
break;
}
exit(1);
}
/* check keys */
if (!force &&
ext2fs_le32_to_cpu(keyb->magic) != KEYBLOCK_MAGIC) {
fprintf(stderr, _("%s: wrong key magic at %llu\n"),
tdb_file, lblk);
exit(1);
}
crc = keyb->crc;
keyb->crc = 0;
key_crc = ext2fs_crc32c_le(~0, (unsigned char *)keyb,
undo_ctx.blocksize);
if (!force && ext2fs_le32_to_cpu(crc) != key_crc) {
fprintf(stderr,
_("%s: key block checksum error at %llu.\n"),
tdb_file, lblk);
exit(1);
}
/* load keys from key block */
lblk++;
max_j = undo_ctx.num_keys - i;
if (max_j > keys_per_block)
max_j = keys_per_block;
for (j = 0, dkey = keyb->keys;
j < max_j;
j++, ikey++, dkey++) {
ikey->fsblk = ext2fs_le64_to_cpu(dkey->fsblk);
ikey->fileblk = lblk;
ikey->blk_crc = ext2fs_le32_to_cpu(dkey->blk_crc);
ikey->size = ext2fs_le32_to_cpu(dkey->size);
lblk += (ikey->size + undo_ctx.blocksize - 1) /
undo_ctx.blocksize;
if (E2UNDO_MAX_EXTENT_BLOCKS * undo_ctx.blocksize <
ikey->size) {
com_err(prg_name, retval,
_("%s: block %llu is too long."),
tdb_file, ikey->fsblk);
exit(1);
}
/* check each block's crc */
retval = io_channel_read_blk64(undo_ctx.undo_file,
ikey->fileblk,
-(int)ikey->size,
buf);
if (retval) {
com_err(prg_name, retval,
_("while fetching block %llu."),
ikey->fileblk);
if (!force)
exit(1);
io_error = 1;
continue;
}
blk_crc = ext2fs_crc32c_le(~0, (unsigned char *)buf,
ikey->size);
if (blk_crc != ikey->blk_crc) {
fprintf(stderr,
_("checksum error in filesystem block "
"%llu (undo blk %llu)\n"),
ikey->fsblk, ikey->fileblk);
if (!force)
exit(1);
csum_error = 1;
}
}
}
ext2fs_free_mem(&keyb);
/* sort keys in fs block order */
qsort(undo_ctx.keys, undo_ctx.num_keys, sizeof(struct undo_key_info),
key_compare);
/* replay */
io_channel_set_blksize(channel, undo_ctx.fs_blocksize);
for (i = 0, ikey = undo_ctx.keys; i < undo_ctx.num_keys; i++, ikey++) {
retval = io_channel_read_blk64(undo_ctx.undo_file,
ikey->fileblk,
-(int)ikey->size,
buf);
if (retval) {
com_err(prg_name, retval,
_("while fetching block %llu."),
ikey->fileblk);
io_error = 1;
continue;
}
if (verbose)
printf("Replayed block of size %u from %llu to %llu\n",
ikey->size, ikey->fileblk, ikey->fsblk);
if (dry_run)
continue;
retval = io_channel_write_blk64(channel, ikey->fsblk,
-(int)ikey->size, buf);
if (retval) {
com_err(prg_name, retval,
_("while writing block %llu."), ikey->fsblk);
io_error = 1;
}
}
if (csum_error)
fprintf(stderr, _("Undo file corruption; run e2fsck NOW!\n"));
if (io_error)
fprintf(stderr, _("IO error during replay; run e2fsck NOW!\n"));
if (!(ext2fs_le32_to_cpu(undo_ctx.hdr.state) & E2UNDO_STATE_FINISHED)) {
force = 1;
fprintf(stderr, _("Incomplete undo record; run e2fsck.\n"));
}
ext2fs_free_mem(&buf);
ext2fs_free_mem(&undo_ctx.keys);
io_channel_close(channel);
/* If there were problems, try to force a fsck */
if (!dry_run && (force || csum_error || io_error)) {
retval = ext2fs_open2(device_name, NULL,
EXT2_FLAG_RW | EXT2_FLAG_64BITS, 0, 0,
manager, &fs);
if (retval)
goto out;
fs->super->s_state &= ~EXT2_VALID_FS;
if (csum_error || io_error)
fs->super->s_state |= EXT2_ERROR_FS;
ext2fs_mark_super_dirty(fs);
ext2fs_close_free(&fs);
}
out:
io_channel_close(undo_ctx.undo_file);
return csum_error;
}