Fix half done initialization of sqfs_dir_reader_open_dir

The sqfs_dir_reader_open_dir function tried to take a short-cut by
returning early if the target directory is empty. However, this left
some field unchanged from the previous directory.

If iterating over a directory and then deciding to enter a sub-directory
that happens to be empty, the directory reader will keep the settings
for the current directory. After calling sqfs_dir_reader_rewind, the
sub-directory will suddenly report the contents of the parent.

A similar check is added to the rewind function to not track back on
the meta data reader in that case.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 6 insertions, 3 deletions

diff --git a/lib/sqfs/dir_reader.c b/lib/sqfs/dir_reader.c
index 65962d8..e6467ef 100644
--- a/lib/sqfs/dir_reader.c
+++ b/lib/sqfs/dir_reader.c
@@ -145,15 +145,15 @@ int sqfs_dir_reader_open_dir(sqfs_dir_reader_t *rd,
 	rd->size = size;
 	rd->entries = 0;
 
-	if (rd->size <= sizeof(rd->hdr))
-		return 0;
-
 	block_start += rd->super->directory_table_start;
 
 	rd->dir_block_start = block_start;
 	rd->dir_offset = offset;
 	rd->start_size = size;
 
+	if (rd->size <= sizeof(rd->hdr))
+		return 0;
+
 	return sqfs_meta_reader_seek(rd->meta_dir, block_start, offset);
 }
 
@@ -200,6 +200,9 @@ int sqfs_dir_reader_rewind(sqfs_dir_reader_t *rd)
 	rd->size = rd->start_size;
 	rd->entries = 0;
 
+	if (rd->size <= sizeof(rd->hdr))
+		return 0;
+
 	return sqfs_meta_reader_seek(rd->meta_dir, rd->dir_block_start,
 				     rd->dir_offset);
 }