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/*
* 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.
*
* This program may be used under the provisions of the GNU Public
* License, *EXCEPT* that a binary copy of the executable may not be
* packaged as a part of binary package which is distributed as part
* of a Linux distribution. (Yes, this violates the Debian Free
* Software Guidelines in terms of restricting its field of use.
* That's the point. I don't want this program being distributed in
* Debian, because I don't care to support it, and the maintainer,
* Yann Dirson, doesn't seem to pay attention to my wishes on this
* matter. So I'm delibiately adding this clause so it violates the
* Debian Free Software Guidelines to force him to take it out. If
* this doesn't work, I'll have to remove it from the upstream source
* distribution at the next release. End of Rant. :-)
*
*
* 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.
*
* This still doesn't handle disks >2G.
*
* 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
*
*/
/*
* 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; it
* will occasionally find other blocks that by coincidence have this
* signature - often these can be recognised by their ridiculous
* dates).
*
* For each superblock found, it prints the offset in bytes, the
* offset in 1024-byte blocks, the size of ext2 partition in 1024-byte
* blocks, the filesystem blocksize (given as log(blocksize)-10, so
* that 0 means 1024), the block group number (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.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <linux/ext2_fs.h>
#include "nls-enable.h"
main(int argc, char *argv[])
{
int i;
int skiprate=512; /* one sector */
long sk=0; /* limited to 2G filesystems!! */
FILE *f;
char *s;
time_t tm;
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, "");
bindtextdomain(NLS_CAT_NAME, LOCALEDIR);
textdomain(NLS_CAT_NAME);
#endif
if (argc<2) {
fprintf(stderr,
_("Usage: findsuper device [skiprate [start]]\n"));
exit(1);
}
if (argc>2)
skiprate=atoi(argv[2]);
if (skiprate<512) {
fprintf(stderr,
_("Do you really want to skip less than a sector??\n"));
exit(2);
}
if (argc>3)
sk=atol(argv[3]);
if (sk<0) {
fprintf(stderr,_("Have to start at 0 or greater,not %ld\n"),sk);
exit(1);
}
f=fopen(argv[1],"r");
if (!f) {
perror(argv[1]);
exit(1);
}
/* Now, go looking for the superblock ! */
printf(" thisoff block fs_blk_sz blksz grp last_mount\n");
for (;!feof(f) && (i=fseek(f,sk,SEEK_SET))!= -1; sk+=skiprate){
if (i=fread(&ext2,sizeof(ext2),1, f)!=1) {
perror(_("read failed"));
}
if (ext2.s_magic != EXT2_SUPER_MAGIC)
continue;
tm = ext2.s_mtime;
s=ctime(&tm);
s[24]=0;
printf("%9ld %9ld %9ld %5ld %4d %s\n", sk,
sk/1024, ext2.s_blocks_count,
ext2.s_log_block_size,
ext2.s_block_group_nr, s);
}
printf(_("Failed on %d at %ld\n"), i, sk);
fclose(f);
}
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