Replace reads in squashfs with positional reads

In most cases, we know exactely where the data that we want to read is
on disk, so instead of using read() on the squashfs (or lseek + read),
the code can in many places be cleaned up to use the pread wrapper
read_data_at instead.

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

1 files changed, 2 insertions, 8 deletions

diff --git a/lib/sqfs/id_table_read.c b/lib/sqfs/id_table_read.c
index 7147f2e..1e92f75 100644
--- a/lib/sqfs/id_table_read.c
+++ b/lib/sqfs/id_table_read.c
@@ -38,15 +38,12 @@ int id_table_read(id_table_t *tbl, int fd, sqfs_super_t *super,
 	tbl->num_ids = super->id_count;
 	tbl->max_ids = super->id_count;
 
-	if (lseek(fd, super->id_table_start, SEEK_SET) == (off_t)-1)
-		goto fail_seek;
-
 	block_count = super->id_count / 2048;
 	if (super->id_count % 2048)
 		++block_count;
 
-	if (read_data("reading ID table", fd, blocks,
-		      sizeof(blocks[0]) * block_count)) {
+	if (read_data_at("reading ID table", super->id_table_start, fd,
+			 blocks, sizeof(blocks[0]) * block_count)) {
 		return -1;
 	}
 
@@ -82,7 +79,4 @@ int id_table_read(id_table_t *tbl, int fd, sqfs_super_t *super,
 fail_meta:
 	meta_reader_destroy(m);
 	return -1;
-fail_seek:
-	perror("seeking to ID table");
-	return -1;
 }