5 files changed, 22 insertions, 43 deletions

diff --git a/lib/sqfs/data_reader.c b/lib/sqfs/data_reader.c
index 4fbd97a..e03a436 100644
--- a/lib/sqfs/data_reader.c
+++ b/lib/sqfs/data_reader.c
@@ -65,6 +65,7 @@ int data_reader_dump_file(data_reader_t *data, file_info_t *fi, int outfd,
 			  bool allow_sparse)
 {
 	size_t i, count, fragsz, unpackedsz;
+	off_t sqfs_location;
 	uint64_t filesz = 0;
 	bool compressed;
 	uint32_t bs;
@@ -81,8 +82,7 @@ int data_reader_dump_file(data_reader_t *data, file_info_t *fi, int outfd,
 	}
 
 	if (count > 0) {
-		if (lseek(data->sqfsfd, fi->startblock, SEEK_SET) == (off_t)-1)
-			goto fail_seek;
+		sqfs_location = fi->startblock;
 
 		for (i = 0; i < count; ++i) {
 			bs = fi->blocksizes[i];
@@ -112,9 +112,13 @@ int data_reader_dump_file(data_reader_t *data, file_info_t *fi, int outfd,
 			if (bs == 0) {
 				memset(data->buffer, 0, unpackedsz);
 				compressed = false;
-			} else if (read_data("reading data block",
-					     data->sqfsfd, data->buffer, bs)) {
-				return -1;
+			} else {
+				if (read_data_at("reading data block",
+						 sqfs_location, data->sqfsfd,
+						 data->buffer, bs)) {
+					return -1;
+				}
+				sqfs_location += bs;
 			}
 
 			if (compressed) {
@@ -157,9 +161,6 @@ int data_reader_dump_file(data_reader_t *data, file_info_t *fi, int outfd,
 fail_sparse:
 	perror("creating sparse output file");
 	return -1;
-fail_seek:
-	perror("seek on squashfs");
-	return -1;
 fail_bs:
 	fputs("found compressed block larger than block size\n", stderr);
 	return -1;
diff --git a/lib/sqfs/frag_reader.c b/lib/sqfs/frag_reader.c
index 87e4c35..721286c 100644
--- a/lib/sqfs/frag_reader.c
+++ b/lib/sqfs/frag_reader.c
@@ -31,11 +31,6 @@ static int precache_block(frag_reader_t *f, size_t i)
 	if (i == f->current_index)
 		return 0;
 
-	if (lseek(f->fd, f->tbl[i].start_offset, SEEK_SET) == (off_t)-1) {
-		perror("seeking to fragment location");
-		return -1;
-	}
-
 	compressed = (f->tbl[i].size & (1 << 24)) == 0;
 	size = f->tbl[i].size & ((1 << 24) - 1);
 
@@ -44,8 +39,10 @@ static int precache_block(frag_reader_t *f, size_t i)
 		return -1;
 	}
 
-	if (read_data("reading fragment", f->fd, f->buffer, size))
+	if (read_data_at("reading fragment", f->tbl[i].start_offset,
+			 f->fd, f->buffer, size)) {
 		return -1;
+	}
 
 	if (compressed) {
 		ret = f->cmp->do_block(f->cmp, f->buffer, size,
@@ -95,11 +92,8 @@ frag_reader_t *frag_reader_create(sqfs_super_t *super, int fd,
 		goto fail_rd;
 
 	/* read the meta block offset table */
-	if (lseek(fd, super->fragment_table_start, SEEK_SET) == (off_t)-1)
-		goto fail_seek;
-
-	if (read_data("reading fragment table", fd, locations,
-		      blockcount * sizeof(locations[0]))) {
+	if (read_data_at("reading fragment table", super->fragment_table_start,
+			 fd, locations, blockcount * sizeof(locations[0]))) {
 		goto fail;
 	}
 
@@ -139,9 +133,6 @@ frag_reader_t *frag_reader_create(sqfs_super_t *super, int fd,
 	f->block_size = super->block_size;
 	f->current_index = count;
 	return f;
-fail_seek:
-	perror("seek to fragment table");
-	goto fail;
 fail_rd:
 	perror("reading fragment table");
 	goto fail;
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;
 }
diff --git a/lib/sqfs/meta_reader.c b/lib/sqfs/meta_reader.c
index 96b59fd..2c6ec97 100644
--- a/lib/sqfs/meta_reader.c
+++ b/lib/sqfs/meta_reader.c
@@ -68,14 +68,11 @@ int meta_reader_seek(meta_reader_t *m, uint64_t block_start, size_t offset)
 		return 0;
 	}
 
-	if (lseek(m->fd, block_start, SEEK_SET) == (off_t)-1) {
-		perror("seek on image file");
+	if (read_data_at("reading meta data header", block_start,
+			 m->fd, &header, 2)) {
 		return -1;
 	}
 
-	if (read_data("reading meta data header", m->fd, &header, 2))
-		return -1;
-
 	header = le16toh(header);
 	compressed = (header & 0x8000) == 0;
 	size = header & 0x7FFF;
@@ -92,8 +89,10 @@ int meta_reader_seek(meta_reader_t *m, uint64_t block_start, size_t offset)
 
 	memset(m->data, 0, sizeof(m->data));
 
-	if (read_data("reading meta data block", m->fd, m->data, size))
+	if (read_data_at("reading meta data block", block_start + 2,
+			 m->fd, m->data, size)) {
 		return -1;
+	}
 
 	if (compressed) {
 		ret = m->cmp->do_block(m->cmp, m->data, size,
diff --git a/lib/sqfs/read_super.c b/lib/sqfs/read_super.c
index 1a84ff9..fff3d50 100644
--- a/lib/sqfs/read_super.c
+++ b/lib/sqfs/read_super.c
@@ -15,10 +15,7 @@ int sqfs_super_read(sqfs_super_t *super, int fd)
 	sqfs_super_t temp;
 	int i;
 
-	if (lseek(fd, 0, SEEK_SET) == (off_t)-1)
-		goto fail_seek;
-
-	if (read_data("reading super block", fd, &temp, sizeof(temp)))
+	if (read_data_at("reading super block", 0, fd, &temp, sizeof(temp)))
 		return -1;
 
 	temp.magic = le32toh(temp.magic);
@@ -87,7 +84,4 @@ int sqfs_super_read(sqfs_super_t *super, int fd)
 
 	memcpy(super, &temp, sizeof(temp));
 	return 0;
-fail_seek:
-	perror("squashfs writing super block: seek on output file");
-	return -1;
 }