/*
* findsuper --- quick hacked up program to find ext2 superblocks.
*
* This is a hack, and really shouldn't be installed anywhere. If you
* need a program which does this sort of functionality, please try
* using gpart program.
*
* Portions Copyright 1998-2000, Theodore Ts'o.
*
* Well, here's my linux version of findsuper.
* I'm sure you coulda done it faster. :)
* IMHO there isn't as much interesting data to print in the
* linux superblock as there is in the SunOS superblock--disk geometry is
* not there...and linux seems to update the dates in all the superblocks.
* SunOS doesn't ever touch the backup superblocks after the fs is created,
* as far as I can tell, so the date is more interesting IMHO and certainly
* marks which superblocks are backup ones.
*
* I wanted to add msdos support, but I couldn't make heads or tails
* of the kernel include files to find anything I could look for in msdos.
*
* Reading every block of a Sun partition is fairly quick. Doing the
* same under linux (slower hardware I suppose) just isn't the same.
* It might be more useful to default to reading the first (second?) block
* on each cyl; however, if the disk geometry is wrong, this is useless.
* But ya could still get the cyl size to print the numbers as cyls instead
* of blocks...
*
* run this as (for example)
* findsuper /dev/hda
* findsuper /dev/hda 437760 1024 (my disk has cyls of 855*512)
*
* I suppose the next step is to figgure out a way to determine if
* the block found is the first superblock somehow, and if so, build
* a partition table from the superblocks found... but this is still
* useful as is.
*
* Steve
* ssd@nevets.oau.org
* ssd@mae.engr.ucf.edu
*
* Additional notes by Andreas Dilger <adilger@turbolinux.com>:
* - fixed to support > 2G devices by using lseek64
* - add reliability checking for the superblock to avoid random garbage
* - add adaptive progress meter
*
* It _should_ also handle signals and tell you the ending block, so
* that you can resume at a later time, but it doesn't yet...
*
* Note that gpart does not appear to find all superblocks that aren't aligned
* with the start of a possible partition, so it is not useful in systems
* with LVM or similar setups which don't use fat partition alignment.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*/
/*
* Documentation addendum added by Andreas dwguest@win.tue.nl/aeb@cwi.nl
*
* The program findsuper is a utility that scans a disk and finds
* copies of ext2 superblocks (by checking for the ext2 signature).
*
* For each superblock found, it prints the offset in bytes, the
* offset in 1024-byte blocks, the size of the ext2 partition in fs
* blocks, the filesystem blocksize (in bytes), the block group number
* (always 0 for older ext2 systems), and a timestamp (s_mtime).
*
* This program can be used to retrieve partitions that have been
* lost. The superblock for block group 0 is found 1 block (2
* sectors) after the partition start.
*
* For new systems that have a block group number in the superblock it
* is immediately clear which superblock is the first of a partition.
* For old systems where no group numbers are given, the first
* superblock can be recognised by the timestamp: all superblock
* copies have the creation time in s_mtime, except the first, which
* has the last time e2fsck or tune2fs wrote to the filesystem.
*
*/
#define _FILE_OFFSET_BITS 64
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <time.h>
#include "ext2fs/ext2_fs.h"
#include "ext2fs/ext2fs.h"
#include "nls-enable.h"
#undef DEBUG
#ifdef DEBUG
#define WHY(fmt, arg...) { printf("\r%Ld: " fmt, sk, ##arg) ; continue; }
#else
#define WHY(fmt, arg...) { continue; }
#endif
static void usage(void)
{
fprintf(stderr,
_("Usage: findsuper device [skipbytes [startkb]]\n"));
exit(1);
}
int main(int argc, char *argv[])
{
int skiprate=512; /* one sector */
loff_t sk=0, skl=0;
int fd;
char *s;
time_t tm, last = time(0);
loff_t interval = 1024 * 1024;
int c, print_jnl_copies = 0;
const char * device_name;
struct ext2_super_block ext2;
/* interesting fields: EXT2_SUPER_MAGIC
* s_blocks_count s_log_block_size s_mtime s_magic s_lastcheck */
#ifdef ENABLE_NLS
setlocale(LC_MESSAGES, "");
setlocale(LC_CTYPE, "");
bindtextdomain(NLS_CAT_NAME, LOCALEDIR);
textdomain(NLS_CAT_NAME);
set_com_err_gettext(gettext);
#endif
while ((c = getopt (argc, argv, "j")) != EOF) {
switch (c) {
case 'j':
print_jnl_copies++;
break;
default:
usage();
}
}
if (optind == argc)
usage();
device_name = argv[optind++];
if (optind < argc) {
skiprate = strtol(argv[optind], &s, 0);
if (s == argv[optind]) {
fprintf(stderr,_("skipbytes should be a number, not %s\n"), s);
exit(1);
}
optind++;
}
if (skiprate & 0x1ff) {
fprintf(stderr,
_("skipbytes must be a multiple of the sector size\n"));
exit(2);
}
if (optind < argc) {
sk = skl = strtoll(argv[optind], &s, 0) << 10;
if (s == argv[optind]) {
fprintf(stderr,
_("startkb should be a number, not %s\n"), s);
exit(1);
}
optind++;
}
if (sk < 0) {
fprintf(stderr, _("startkb should be positive, not %llu\n"),sk);
exit(1);
}
fd = open(device_name, O_RDONLY);
if (fd < 0) {
perror(device_name);
exit(1);
}
/* Now, go looking for the superblock! */
printf(_("starting at %llu, with %u byte increments\n"), sk, skiprate);
if (print_jnl_copies)
printf(_("[*] probably superblock written in the ext3 "
"journal superblock,\n\tso start/end/grp wrong\n"));
printf(_("byte_offset byte_start byte_end fs_blocks blksz grp last_mount_time sb_uuid label\n"));
for (; lseek64(fd, sk, SEEK_SET) != -1 &&
read(fd, &ext2, 512) == 512; sk += skiprate) {
static unsigned char last_uuid[16] = "blah";
unsigned long long bsize, grpsize;
int jnl_copy, sb_offset;
if (sk && !(sk & (interval - 1))) {
time_t now, diff;
now = time(0);
diff = now - last;
if (diff > 0) {
s = ctime(&now);
s[24] = 0;
printf("\r%11Lu: %8LukB/s @ %s", sk,
(((sk - skl)) / diff) >> 10, s);
fflush(stdout);
}
if (diff < 5)
interval <<= 1;
else if (diff > 20)
interval >>= 1;
last = now;
skl = sk;
}
if (ext2.s_magic != EXT2_SUPER_MAGIC)
continue;
if (ext2.s_log_block_size > 6)
WHY("log block size > 6 (%u)\n", ext2.s_log_block_size);
if (ext2fs_r_blocks_count(&ext2) > ext2fs_blocks_count(&ext2))
WHY("r_blocks_count > blocks_count (%u > %u)\n",
ext2fs_r_blocks_count(&ext2),
ext2fs_blocks_count(&ext2));
if (ext2fs_free_blocks_count(&ext2) > ext2fs_blocks_count(&ext2))
WHY("free_blocks_count > blocks_count\n (%u > %u)\n",
ext2fs_free_blocks_count(&ext2),
ext2fs_blocks_count(&ext2));
if (ext2.s_free_inodes_count > ext2.s_inodes_count)
WHY("free_inodes_count > inodes_count (%u > %u)\n",
ext2.s_free_inodes_count, ext2.s_inodes_count);
tm = ext2.s_mtime;
s = ctime(&tm);
s[24] = 0;
bsize = 1 << (ext2.s_log_block_size + 10);
grpsize = bsize * ext2.s_blocks_per_group;
if (memcmp(ext2.s_uuid, last_uuid, sizeof(last_uuid)) == 0 &&
ext2.s_rev_level > 0 && ext2.s_block_group_nr == 0) {
jnl_copy = 1;
} else {
jnl_copy = 0;
memcpy(last_uuid, ext2.s_uuid, sizeof(last_uuid));
}
if (ext2.s_block_group_nr == 0 || bsize == 1024)
sb_offset = 1024;
else
sb_offset = 0;
if (jnl_copy && !print_jnl_copies)
continue;
printf("\r%11Lu %11Lu%s %11Lu%s %9u %5Lu %4u%s %s %02x%02x%02x%02x %s\n",
sk, sk - ext2.s_block_group_nr * grpsize - sb_offset,
jnl_copy ? "*":" ",
sk + ext2fs_blocks_count(&ext2) * bsize -
ext2.s_block_group_nr * grpsize - sb_offset,
jnl_copy ? "*" : " ", ext2fs_blocks_count(&ext2), bsize,
ext2.s_block_group_nr, jnl_copy ? "*" : " ", s,
ext2.s_uuid[0], ext2.s_uuid[1],
ext2.s_uuid[2], ext2.s_uuid[3], ext2.s_volume_name);
}
printf(_("\n%11Lu: finished with errno %d\n"), sk, errno);
close(fd);
return errno;
}