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Diffstat (limited to 'misc/findsuper.c')
| -rw-r--r-- | misc/findsuper.c | 269 |
1 files changed, 269 insertions, 0 deletions
diff --git a/misc/findsuper.c b/misc/findsuper.c new file mode 100644 index 0000000..7e78c1f --- /dev/null +++ b/misc/findsuper.c @@ -0,0 +1,269 @@ +/* + * 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 figure 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 recognized 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 "config.h" +#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 "support/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 */ + ext2_loff_t sk=0, skl=0; + int fd; + char *s; + time_t tm, last = time(0); + ext2_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 mkfs/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); + + if (ext2.s_mkfs_time != 0) + tm = ext2.s_mkfs_time; + else + 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_LEN_STR(ext2.s_volume_name)); + } + printf(_("\n%11Lu: finished with errno %d\n"), sk, errno); + close(fd); + + return errno; +} |