From 68c41a5f5f2649f49d6eb2aecba7fb248b57e91e Mon Sep 17 00:00:00 2001
From: Karel Zak
Date: Mon, 5 Aug 2013 15:24:30 +0200
Subject: libmount: be robust when work with loopdev backing file paths

It's usually unnecessary as we compare devno and ino, but let's
use absolute paths for situations when it's necessary to compare
paths as strings.

Signed-off-by: Karel Zak <kzak@redhat.com>
---
 libmount/src/context_loopdev.c | 25 ++++++++++++-------------
 libmount/src/context_umount.c  | 10 +++++-----
 2 files changed, 17 insertions(+), 18 deletions(-)

(limited to 'libmount')

diff --git a/libmount/src/context_loopdev.c b/libmount/src/context_loopdev.c
index 37fadb70b..44a7216b8 100644
--- a/libmount/src/context_loopdev.c
+++ b/libmount/src/context_loopdev.c
@@ -86,6 +86,8 @@ is_mounted_same_loopfile(struct libmnt_context *cxt,
 	struct libmnt_iter itr;
 	struct libmnt_fs *fs;
 	struct libmnt_cache *cache;
+	const char *bf;
+	int rc = 0;
 
 	assert(cxt);
 	assert(cxt->fs);
@@ -100,39 +102,36 @@ is_mounted_same_loopfile(struct libmnt_context *cxt,
 	cache = mnt_context_get_cache(cxt);
 	mnt_reset_iter(&itr, MNT_ITER_BACKWARD);
 
+	bf = cache ? mnt_resolve_path(backing_file, cache) : backing_file;
+
 	/* Search for a mountpoint node in mtab, proceed if any of these have the
 	 * loop option set or the device is a loop device
 	 */
-	while (mnt_table_next_fs(tb, &itr, &fs) == 0) {
+	while (rc == 0 && mnt_table_next_fs(tb, &itr, &fs) == 0) {
 		const char *src = mnt_fs_get_source(fs);
 		const char *opts = mnt_fs_get_user_options(fs);
 		char *val;
 		size_t len;
-		int res = 0;
 
 		if (!src || !mnt_fs_match_target(fs, target, cache))
 			continue;
 
+		rc = 0;
+
 		if (strncmp(src, "/dev/loop", 9) == 0) {
-			res = loopdev_is_used((char *) src, backing_file,
-					offset, LOOPDEV_FL_OFFSET);
+			rc = loopdev_is_used((char *) src, bf, offset, LOOPDEV_FL_OFFSET);
 
 		} else if (opts && (cxt->user_mountflags & MNT_MS_LOOP) &&
 		    mnt_optstr_get_option(opts, "loop", &val, &len) == 0 && val) {
 
 			val = strndup(val, len);
-			res = loopdev_is_used((char *) val, backing_file,
-					offset, LOOPDEV_FL_OFFSET);
+			rc = loopdev_is_used((char *) val, bf, offset, LOOPDEV_FL_OFFSET);
 			free(val);
 		}
-
-		if (res) {
-			DBG(CXT, mnt_debug_h(cxt, "%s already mounted", backing_file));
-			return 1;
-		}
 	}
-
-	return 0;
+	if (rc)
+		DBG(CXT, mnt_debug_h(cxt, "%s already mounted", backing_file));
+	return rc;
 }
 
 int mnt_context_setup_loopdev(struct libmnt_context *cxt)
diff --git a/libmount/src/context_umount.c b/libmount/src/context_umount.c
index b02902c45..2e912c0dc 100644
--- a/libmount/src/context_umount.c
+++ b/libmount/src/context_umount.c
@@ -162,11 +162,9 @@ try_loopdev:
 
 		if (stat(tgt, &st) == 0 && S_ISREG(st.st_mode)) {
 			int count;
+			const char *bf = cache ? mnt_resolve_path(tgt, cache) : tgt;
 
-			cn_tgt = mnt_resolve_path(tgt, cache);
-			count = loopdev_count_by_backing_file(cn_tgt, &loopdev);
-			if (!cache)
-				free(cn_tgt);
+			count = loopdev_count_by_backing_file(bf, &loopdev);
 			if (count == 1) {
 				DBG(CXT, mnt_debug_h(cxt,
 					"umount: %s --> %s (retry)", tgt, loopdev));
@@ -361,7 +359,9 @@ static int evaluate_permissions(struct libmnt_context *cxt)
 		 */
 		fs = mnt_table_find_target(fstab, tgt, MNT_ITER_FORWARD);
 		if (fs) {
-			const char *dev = mnt_fs_get_srcpath(cxt->fs);		/* devname from mtab */
+			struct libmnt_cache *cache = mnt_context_get_cache(cxt);
+			const char *sp = mnt_fs_get_srcpath(cxt->fs);		/* devname from mtab */
+			const char *dev = sp && cache ? mnt_resolve_path(sp, cache) : sp;
 
 			if (!dev || !is_associated_fs(dev, fs))
 				fs = NULL;
-- 
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