From: Marcus Huewe <suse-tux@gmx.de>
Date: Thu, 12 May 2016 19:36:00 +0000 (-0400)
Subject: e2undo: add "-o offset" option to specify the filesystem offset
X-Git-Tag: v1.43~6
X-Git-Url: https://git.whamcloud.com/gitweb?a=commitdiff_plain;h=6930537d528c00c81d76a301936b198e16b460d9;p=tools%2Fe2fsprogs.git

e2undo: add "-o offset" option to specify the filesystem offset

This is useful if the filesystem is located at an arbitrary
offset instead of the beginning of a device or file.

Signed-off-by: Marcus Huewe <suse-tux@gmx.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---

diff --git a/misc/e2undo.8.in b/misc/e2undo.8.in
index 1b7dee3..da8b918 100644
--- a/misc/e2undo.8.in
+++ b/misc/e2undo.8.in
@@ -46,6 +46,11 @@ Display a usage message.
 .B \-n
 Dry-run; do not actually write blocks back to the filesystem.
 .TP
+.BI \-o " offset"
+Specify the filesystem's
+.I offset
+(in bytes) from the beginning of the device or file.
+.TP
 .B \-v
 Report which block we're currently replaying.
 .SH AUTHOR
diff --git a/misc/e2undo.c b/misc/e2undo.c
index 7c7326a..4ea78cc 100644
--- a/misc/e2undo.c
+++ b/misc/e2undo.c
@@ -292,6 +292,8 @@ int main(int argc, char *argv[])
 	__u32 key_crc, blk_crc, hdr_crc;
 	blk64_t lblk;
 	ext2_filsys fs;
+	__u64 offset;
+	char opt_offset_string[40] = { 0 };
 
 #ifdef ENABLE_NLS
 	setlocale(LC_MESSAGES, "");
@@ -303,7 +305,7 @@ int main(int argc, char *argv[])
 	add_error_table(&et_ext2_error_table);
 
 	prg_name = argv[0];
-	while ((c = getopt(argc, argv, "fhnvz:")) != EOF) {
+	while ((c = getopt(argc, argv, "fhno:vz:")) != EOF) {
 		switch (c) {
 		case 'f':
 			force = 1;
@@ -314,6 +316,16 @@ int main(int argc, char *argv[])
 		case 'n':
 			dry_run = 1;
 			break;
+		case 'o':
+			offset = strtoull(optarg, &buf, 0);
+			if (*buf) {
+				com_err(prg_name, 0,
+						_("illegal offset - %s"), optarg);
+				exit(1);
+			}
+			/* used to indicate that an offset was specified */
+			opt_offset_string[0] = 1;
+			break;
 		case 'v':
 			verbose = 1;
 			break;
@@ -423,6 +435,17 @@ int main(int argc, char *argv[])
 		exit(1);
 	}
 
+	if (*opt_offset_string) {
+		retval = snprintf(opt_offset_string, sizeof(opt_offset_string),
+						  "offset=%llu", offset);
+		if (retval >= sizeof(opt_offset_string)) {
+			/* should not happen... */
+			com_err(prg_name, 0, _("specified offset is too large"));
+			exit(1);
+		}
+		io_channel_set_options(channel, opt_offset_string);
+	}
+
 	if (!force && check_filesystem(&undo_ctx, channel))
 		exit(1);