Update findsuper to support > 2GB device sizes.
Add extra validity checks over just ext2 magic detection.
Add progress meter.

diff --git a/misc/findsuper.c b/misc/findsuper.c
index 35bf9b9..f1e2315 100644
--- a/misc/findsuper.c
+++ b/misc/findsuper.c
@@ -30,8 +30,6 @@
  * 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.
  * 
@@ -54,23 +52,30 @@
  *		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.
  */
 
 /*
  * 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).
+ * 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 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).
+ * offset in 1024-byte blocks, the size of 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
@@ -85,23 +90,35 @@
  * 
  */
 
+#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 "nls-enable.h"
 
+#undef DEBUG
 
-main(int argc, char *argv[])
+#ifdef DEBUG
+#define WHY(fmt, arg...) { printf("\r%Ld: " fmt, sk, ##arg) ; continue; }
+#else
+#define WHY(fmt, arg...) { continue; }
+#endif
+
+int main(int argc, char *argv[])
 {
-	int i;
 	int skiprate=512;		/* one sector */
-	long sk=0;			/* limited to 2G filesystems!! */
-	FILE *f;
+	loff_t sk=0, skl=0;
+	int fd;
 	char *s;
-	time_t tm;
+	time_t tm, last = time(0);
+	loff_t interval = 1024 * 1024;
 
 	struct ext2_super_block ext2;
 	/* interesting fields: EXT2_SUPER_MAGIC
@@ -114,45 +131,86 @@
 #endif
 	if (argc<2) {
 		fprintf(stderr,
-			_("Usage:  findsuper device [skiprate [start]]\n"));
+			_("Usage:  findsuper device [skipbytes [startkb]]\n"));
 		exit(1);
 	}
 	if (argc>2)
-		skiprate=atoi(argv[2]);
-	if (skiprate<512) {
+		skiprate = strtol(argv[2], &s, 0);
+	if (s == argv[2]) {
+		fprintf(stderr,_("skiprate should be a number, not %s\n"), s);
+		exit(1);
+	}
+	if (skiprate & 0x1ff) {
 		fprintf(stderr,
-			_("Do you really want to skip less than a sector??\n"));
+			_("skipbytes must be a multiple of the sector size\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);
+		sk = skl = strtoll(argv[3], &s, 0) << 10;
+	if (s == argv[3]) {
+		fprintf(stderr,_("startkb should be a number, not %s\n"), s);
 		exit(1);
 	}
-	f=fopen(argv[1],"r");
-	if (!f) {
+	if (sk < 0) {
+		fprintf(stderr,_("startkb should be positive, not %Ld\n"), sk);
+		exit(1);
+	}
+	fd = open(argv[1], O_RDONLY);
+	if (fd < 0) {
 		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"));
+	printf(_("starting at %Ld, with %d byte increments\n"), sk, skiprate);
+	printf(_("       thisoff     block fs_blk_sz  blksz grp last_mount\n"));
+	for (; lseek64(fd, sk, SEEK_SET) != -1 &&
+	       read(fd, &ext2, 512) == 512; sk += skiprate) {
+
+		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%14Ld: %8LdkB/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 > 4)
+			WHY("log block size > 4 (%d)\n", ext2.s_log_block_size);
+		if (ext2.s_r_blocks_count > ext2.s_blocks_count)
+			WHY("r_blocks_count > blocks_count (%d > %d)\n",
+			    ext2.s_r_blocks_count, ext2.s_blocks_count);
+		if (ext2.s_free_blocks_count > ext2.s_blocks_count)
+			WHY("free_blocks_count > blocks_count\n (%d > %d)\n",
+			    ext2.s_free_blocks_count, ext2.s_blocks_count);
+		if (ext2.s_free_inodes_count > ext2.s_inodes_count)
+			WHY("free_inodes_count > inodes_count (%d > %d)\n",
+			    ext2.s_free_inodes_count, ext2.s_inodes_count);
+
 		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,
+		printf("\r%14Ld %9Ld %9d %5d %4d %s\n",
+		       sk, sk >> 10, ext2.s_blocks_count,
+		       1 << (ext2.s_log_block_size + 10),
 		       ext2.s_block_group_nr, s);
 	}
-	printf(_("Failed on %d at %ld\n"), i, sk);
-	fclose(f);
+	printf(_("\n%14Ld: finished with errno %d\n"), sk, errno);
+	close(fd);
+
+	return errno;
 }