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/* 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
*/
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <linux/ext2_fs.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 */
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 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");
} else if (ext2.s_magic == EXT2_SUPER_MAGIC){
tm = ext2.s_mtime;
s=ctime(&tm);
s[24]=0;
printf("%9ld %9ld %9ld %5ld %s\n",sk,sk/1024,ext2.s_blocks_count,ext2.s_log_block_size,s);
}
}
printf("Failed on %d at %ld\n", i, sk);
fclose(f);
}
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