Fix: meta reader behaviour if accessing block at location 0

Technically, this should *never* **ever** happen, because a SquashFS
file always starts with a super block, which isn't wrapped in a meta
data block, so a valid SquashFS file will never have a reason to read
from offset 0.

However, this does bite us when doing unit tests where the meta reader
and writer are used on an otherwise empty file. When trying to read
from offset 0, the caching code assumes that we already have that
block, since tha block_offset got initialized to 0.

This commit changes the initialization to set the current block
location to the maximum 64 bit integer, a location we are never
going to read from, since it will always be after the limit.

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

1 files changed, 1 insertions, 0 deletions

diff --git a/lib/sqfs/meta_reader.c b/lib/sqfs/meta_reader.c
index b16b115..a47c1e8 100644
--- a/lib/sqfs/meta_reader.c
+++ b/lib/sqfs/meta_reader.c
@@ -76,6 +76,7 @@ sqfs_meta_reader_t *sqfs_meta_reader_create(sqfs_file_t *file,
 
 	((sqfs_object_t *)m)->copy = meta_reader_copy;
 	((sqfs_object_t *)m)->destroy = meta_reader_destroy;
+	m->block_offset = 0xFFFFFFFFFFFFFFFFUL;
 	m->start = start;
 	m->limit = limit;
 	m->file = file;