2 * findsuper --- quick hacked up program to find ext2 superblocks.
4 * This is a hack, and really shouldn't be installed anywhere. If you
5 * need a program which does this sort of functionality, please try
8 * Portions Copyright 1998-2000, Theodore Ts'o.
10 * Well, here's my linux version of findsuper.
11 * I'm sure you coulda done it faster. :)
12 * IMHO there isn't as much interesting data to print in the
13 * linux superblock as there is in the SunOS superblock--disk geometry is
14 * not there...and linux seems to update the dates in all the superblocks.
15 * SunOS doesn't ever touch the backup superblocks after the fs is created,
16 * as far as I can tell, so the date is more interesting IMHO and certainly
17 * marks which superblocks are backup ones.
19 * I wanted to add msdos support, but I couldn't make heads or tails
20 * of the kernel include files to find anything I could look for in msdos.
22 * Reading every block of a Sun partition is fairly quick. Doing the
23 * same under linux (slower hardware I suppose) just isn't the same.
24 * It might be more useful to default to reading the first (second?) block
25 * on each cyl; however, if the disk geometry is wrong, this is useless.
26 * But ya could still get the cyl size to print the numbers as cyls instead
29 * run this as (for example)
31 * findsuper /dev/hda 437760 1024 (my disk has cyls of 855*512)
33 * I suppose the next step is to figgure out a way to determine if
34 * the block found is the first superblock somehow, and if so, build
35 * a partition table from the superblocks found... but this is still
40 * ssd@mae.engr.ucf.edu
42 * Additional notes by Andreas Dilger <adilger@turbolinux.com>:
43 * - fixed to support > 2G devices by using lseek64
44 * - add reliability checking for the superblock to avoid random garbage
45 * - add adaptive progress meter
47 * It _should_ also handle signals and tell you the ending block, so
48 * that you can resume at a later time, but it doesn't yet...
50 * Note that gpart does not appear to find all superblocks that aren't aligned
51 * with the start of a possible partition, so it is not useful in systems
52 * with LVM or similar setups which don't use fat partition alignment.
55 * This file may be redistributed under the terms of the GNU Public
61 * Documentation addendum added by Andreas dwguest@win.tue.nl/aeb@cwi.nl
63 * The program findsuper is a utility that scans a disk and finds
64 * copies of ext2 superblocks (by checking for the ext2 signature).
66 * For each superblock found, it prints the offset in bytes, the
67 * offset in 1024-byte blocks, the size of the ext2 partition in fs
68 * blocks, the filesystem blocksize (in bytes), the block group number
69 * (always 0 for older ext2 systems), and a timestamp (s_mtime).
71 * This program can be used to retrieve partitions that have been
72 * lost. The superblock for block group 0 is found 1 block (2
73 * sectors) after the partition start.
75 * For new systems that have a block group number in the superblock it
76 * is immediately clear which superblock is the first of a partition.
77 * For old systems where no group numbers are given, the first
78 * superblock can be recognised by the timestamp: all superblock
79 * copies have the creation time in s_mtime, except the first, which
80 * has the last time e2fsck or tune2fs wrote to the filesystem.
84 #define _FILE_OFFSET_BITS 64
95 #include "ext2fs/ext2_fs.h"
96 #include "ext2fs/ext2fs.h"
97 #include "nls-enable.h"
102 #define WHY(fmt, arg...) { printf("\r%Ld: " fmt, sk, ##arg) ; continue; }
104 #define WHY(fmt, arg...) { continue; }
107 static void usage(void)
110 _("Usage: findsuper device [skipbytes [startkb]]\n"));
115 int main(int argc, char *argv[])
117 int skiprate=512; /* one sector */
121 time_t tm, last = time(0);
122 loff_t interval = 1024 * 1024;
123 int c, print_jnl_copies = 0;
124 const char * device_name;
125 struct ext2_super_block ext2;
126 /* interesting fields: EXT2_SUPER_MAGIC
127 * s_blocks_count s_log_block_size s_mtime s_magic s_lastcheck */
130 setlocale(LC_MESSAGES, "");
131 setlocale(LC_CTYPE, "");
132 bindtextdomain(NLS_CAT_NAME, LOCALEDIR);
133 textdomain(NLS_CAT_NAME);
134 set_com_err_gettext(gettext);
137 while ((c = getopt (argc, argv, "j")) != EOF) {
150 device_name = argv[optind++];
153 skiprate = strtol(argv[optind], &s, 0);
154 if (s == argv[optind]) {
155 fprintf(stderr,_("skipbytes should be a number, not %s\n"), s);
160 if (skiprate & 0x1ff) {
162 _("skipbytes must be a multiple of the sector size\n"));
166 sk = skl = strtoll(argv[optind], &s, 0) << 10;
167 if (s == argv[optind]) {
169 _("startkb should be a number, not %s\n"), s);
175 fprintf(stderr, _("startkb should be positive, not %llu\n"),sk);
179 fd = open(device_name, O_RDONLY);
185 /* Now, go looking for the superblock! */
186 printf(_("starting at %llu, with %u byte increments\n"), sk, skiprate);
187 if (print_jnl_copies)
188 printf(_("[*] probably superblock written in the ext3 "
189 "journal superblock,\n\tso start/end/grp wrong\n"));
190 printf(_("byte_offset byte_start byte_end fs_blocks blksz grp last_mount_time sb_uuid label\n"));
191 for (; lseek64(fd, sk, SEEK_SET) != -1 &&
192 read(fd, &ext2, 512) == 512; sk += skiprate) {
193 static unsigned char last_uuid[16] = "blah";
194 unsigned long long bsize, grpsize;
195 int jnl_copy, sb_offset;
197 if (sk && !(sk & (interval - 1))) {
206 printf("\r%11Lu: %8LukB/s @ %s", sk,
207 (((sk - skl)) / diff) >> 10, s);
217 if (ext2.s_magic != EXT2_SUPER_MAGIC)
219 if (ext2.s_log_block_size > 6)
220 WHY("log block size > 6 (%u)\n", ext2.s_log_block_size);
221 if (ext2fs_r_blocks_count(&ext2) > ext2fs_blocks_count(&ext2))
222 WHY("r_blocks_count > blocks_count (%u > %u)\n",
223 ext2fs_r_blocks_count(&ext2),
224 ext2fs_blocks_count(&ext2));
225 if (ext2fs_free_blocks_count(&ext2) > ext2fs_blocks_count(&ext2))
226 WHY("free_blocks_count > blocks_count\n (%u > %u)\n",
227 ext2fs_free_blocks_count(&ext2),
228 ext2fs_blocks_count(&ext2));
229 if (ext2.s_free_inodes_count > ext2.s_inodes_count)
230 WHY("free_inodes_count > inodes_count (%u > %u)\n",
231 ext2.s_free_inodes_count, ext2.s_inodes_count);
236 bsize = 1 << (ext2.s_log_block_size + 10);
237 grpsize = bsize * ext2.s_blocks_per_group;
238 if (memcmp(ext2.s_uuid, last_uuid, sizeof(last_uuid)) == 0 &&
239 ext2.s_rev_level > 0 && ext2.s_block_group_nr == 0) {
243 memcpy(last_uuid, ext2.s_uuid, sizeof(last_uuid));
245 if (ext2.s_block_group_nr == 0 || bsize == 1024)
249 if (jnl_copy && !print_jnl_copies)
251 printf("\r%11Lu %11Lu%s %11Lu%s %9u %5Lu %4u%s %s %02x%02x%02x%02x %s\n",
252 sk, sk - ext2.s_block_group_nr * grpsize - sb_offset,
254 sk + ext2fs_blocks_count(&ext2) * bsize -
255 ext2.s_block_group_nr * grpsize - sb_offset,
256 jnl_copy ? "*" : " ", ext2fs_blocks_count(&ext2), bsize,
257 ext2.s_block_group_nr, jnl_copy ? "*" : " ", s,
258 ext2.s_uuid[0], ext2.s_uuid[1],
259 ext2.s_uuid[2], ext2.s_uuid[3], ext2.s_volume_name);
261 printf(_("\n%11Lu: finished with errno %d\n"), sk, errno);