Move fstree independend parts of xattr_reader to libsquashfs.so

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

7 files changed, 329 insertions, 319 deletions

diff --git a/include/highlevel.h b/include/highlevel.h
index 6b8e2e2..ef10c1e 100644
--- a/include/highlevel.h
+++ b/include/highlevel.h
@@ -15,6 +15,7 @@
 #include "sqfs/data.h"
 #include "sqfs/table.h"
 #include "sqfs/meta_writer.h"
+#include "sqfs/xattr.h"
 #include "data_reader.h"
 #include "fstree.h"
 
@@ -150,4 +151,7 @@ int compressor_cfg_init_options(compressor_config_t *cfg, E_SQFS_COMPRESSOR id,
 
 void compressor_print_help(E_SQFS_COMPRESSOR id);
 
+int xattr_reader_restore_node(xattr_reader_t *xr, fstree_t *fs,
+			      tree_node_t *node, uint32_t xattr);
+
 #endif /* HIGHLEVEL_H */
diff --git a/include/sqfs/xattr.h b/include/sqfs/xattr.h
index 2e48a4e..92fdbfe 100644
--- a/include/sqfs/xattr.h
+++ b/include/sqfs/xattr.h
@@ -9,6 +9,8 @@
 
 #include "config.h"
 
+#include "sqfs/compress.h"
+
 #include <stdbool.h>
 #include <stdint.h>
 #include <stddef.h>
@@ -45,6 +47,8 @@ typedef struct {
 	uint32_t unused;
 } sqfs_xattr_id_table_t;
 
+typedef struct xattr_reader_t xattr_reader_t;
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -58,6 +62,21 @@ int sqfs_get_xattr_prefix_id(const char *key);
 /* Check if a given xattr key can be encoded in squashfs at all. */
 bool sqfs_has_xattr(const char *key);
 
+void xattr_reader_destroy(xattr_reader_t *xr);
+
+xattr_reader_t *xattr_reader_create(int sqfsfd, sqfs_super_t *super,
+				    compressor_t *cmp);
+
+int xattr_reader_get_desc(xattr_reader_t *xr, uint32_t idx,
+			  sqfs_xattr_id_t *desc);
+
+int xattr_reader_seek_kv(xattr_reader_t *xr, const sqfs_xattr_id_t *desc);
+
+sqfs_xattr_value_t *xattr_reader_read_value(xattr_reader_t *xr,
+					    const sqfs_xattr_entry_t *key);
+
+sqfs_xattr_entry_t *xattr_reader_read_key(xattr_reader_t *xr);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/xattr_reader.h b/include/xattr_reader.h
deleted file mode 100644
index 9cacd35..0000000
--- a/include/xattr_reader.h
+++ /dev/null
@@ -1,26 +0,0 @@
-/* SPDX-License-Identifier: GPL-3.0-or-later */
-/*
- * xattr_reader.h
- *
- * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
- */
-#ifndef XATTR_READER_H
-#define XATTR_READER_H
-
-#include "config.h"
-
-#include "sqfs/compress.h"
-#include "sqfs/data.h"
-#include "fstree.h"
-
-typedef struct xattr_reader_t xattr_reader_t;
-
-void xattr_reader_destroy(xattr_reader_t *xr);
-
-xattr_reader_t *xattr_reader_create(int sqfsfd, sqfs_super_t *super,
-				    compressor_t *cmp);
-
-int xattr_reader_restore_node(xattr_reader_t *xr, fstree_t *fs,
-			      tree_node_t *node, uint32_t xattr);
-
-#endif /* XATTR_READER_H */
diff --git a/lib/Makemodule.am b/lib/Makemodule.am
index 180833e..a5db913 100644
--- a/lib/Makemodule.am
+++ b/lib/Makemodule.am
@@ -27,12 +27,12 @@ libsqfshelper_a_SOURCES += lib/sqfshelper/sqfs_reader.c
 libsqfshelper_a_SOURCES += lib/sqfshelper/write_dir.c
 libsqfshelper_a_SOURCES += lib/sqfshelper/write_inode.c
 libsqfshelper_a_SOURCES += lib/sqfshelper/write_export_table.c
-libsqfshelper_a_SOURCES += lib/sqfshelper/xattr_reader.c
 libsqfshelper_a_SOURCES += lib/sqfshelper/print_version.c
+libsqfshelper_a_SOURCES += lib/sqfshelper/xattr_reader.c
 libsqfshelper_a_SOURCES += lib/sqfshelper/compress.c lib/sqfshelper/comp_opt.c
 libsqfshelper_a_SOURCES += include/data_reader.h lib/sqfshelper/data_reader.c
 libsqfshelper_a_SOURCES += include/data_writer.h lib/sqfshelper/data_writer.c
-libsqfshelper_a_SOURCES += include/xattr_reader.h lib/sqfshelper/write_xattr.c
+libsqfshelper_a_SOURCES += lib/sqfshelper/write_xattr.c
 
 libutil_la_SOURCES = lib/util/write_data.c
 libutil_la_SOURCES += lib/util/read_data.c include/util.h
@@ -55,7 +55,7 @@ libsquashfs_la_SOURCES += lib/sqfs/write_table.c include/highlevel.h
 libsquashfs_la_SOURCES += lib/sqfs/read_super.c lib/sqfs/meta_reader.c
 libsquashfs_la_SOURCES += lib/sqfs/read_inode.c
 libsquashfs_la_SOURCES += lib/sqfs/readdir.c
-libsquashfs_la_SOURCES += lib/sqfs/xattr.c
+libsquashfs_la_SOURCES += lib/sqfs/xattr.c lib/sqfs/xattr_reader.c
 libsquashfs_la_SOURCES += lib/sqfs/read_table.c
 libsquashfs_la_SOURCES += lib/sqfs/comp/compressor.c lib/sqfs/comp/internal.h
 libsquashfs_la_SOURCES += lib/sqfs/comp/create_block.c
diff --git a/lib/sqfs/xattr_reader.c b/lib/sqfs/xattr_reader.c
new file mode 100644
index 0000000..862f4af
--- /dev/null
+++ b/lib/sqfs/xattr_reader.c
@@ -0,0 +1,293 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * xattr_reader.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+
+#include "sqfs/meta_reader.h"
+#include "sqfs/xattr.h"
+#include "util.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+
+struct xattr_reader_t {
+	uint64_t xattr_start;
+
+	size_t num_id_blocks;
+	size_t num_ids;
+
+	uint64_t *id_block_starts;
+
+	meta_reader_t *idrd;
+	meta_reader_t *kvrd;
+	sqfs_super_t *super;
+};
+
+static int get_id_block_locations(xattr_reader_t *xr, int sqfsfd,
+				  sqfs_super_t *super)
+{
+	sqfs_xattr_id_table_t idtbl;
+	size_t i;
+
+	if (super->xattr_id_table_start >= super->bytes_used) {
+		fputs("xattr ID location table is after end of filesystem\n",
+		      stderr);
+		return -1;
+	}
+
+	if (read_data_at("reading xattr ID location table",
+			 super->xattr_id_table_start,
+			 sqfsfd, &idtbl, sizeof(idtbl))) {
+		return -1;
+	}
+
+	xr->xattr_start = le64toh(idtbl.xattr_table_start);
+	xr->num_ids = le32toh(idtbl.xattr_ids);
+	xr->num_id_blocks =
+		(xr->num_ids * sizeof(sqfs_xattr_id_t)) / SQFS_META_BLOCK_SIZE;
+
+	if ((xr->num_ids * sizeof(sqfs_xattr_id_t)) % SQFS_META_BLOCK_SIZE)
+		xr->num_id_blocks += 1;
+
+	xr->id_block_starts = alloc_array(sizeof(uint64_t), xr->num_id_blocks);
+	if (xr->id_block_starts == NULL) {
+		perror("allocating xattr ID location table");
+		return -1;
+	}
+
+	if (read_data_at("reading xattr ID block locations",
+			 super->xattr_id_table_start + sizeof(idtbl),
+			 sqfsfd, xr->id_block_starts,
+			 sizeof(uint64_t) * xr->num_id_blocks)) {
+		goto fail;
+	}
+
+	for (i = 0; i < xr->num_id_blocks; ++i) {
+		xr->id_block_starts[i] = le64toh(xr->id_block_starts[i]);
+
+		if (xr->id_block_starts[i] > super->bytes_used) {
+			fputs("found xattr ID block that is past "
+			      "end of filesystem\n", stderr);
+			goto fail;
+		}
+	}
+
+	return 0;
+fail:
+	free(xr->id_block_starts);
+	xr->id_block_starts = NULL;
+	return -1;
+}
+
+sqfs_xattr_entry_t *xattr_reader_read_key(xattr_reader_t *xr)
+{
+	sqfs_xattr_entry_t key, *out;
+	const char *prefix;
+	size_t plen, total;
+
+	if (meta_reader_read(xr->kvrd, &key, sizeof(key)))
+		return NULL;
+
+	key.type = le16toh(key.type);
+	key.size = le16toh(key.size);
+
+	prefix = sqfs_get_xattr_prefix(key.type & SQUASHFS_XATTR_PREFIX_MASK);
+	if (prefix == NULL) {
+		fprintf(stderr, "found unknown xattr type %u\n",
+			key.type & SQUASHFS_XATTR_PREFIX_MASK);
+		return NULL;
+	}
+
+	plen = strlen(prefix);
+
+	if (SZ_ADD_OV(plen, key.size, &total) || SZ_ADD_OV(total, 1, &total) ||
+	    SZ_ADD_OV(sizeof(*out), total, &total)) {
+		errno = EOVERFLOW;
+		goto fail_alloc;
+	}
+
+	out = calloc(1, total);
+	if (out == NULL) {
+		goto fail_alloc;
+	}
+
+	*out = key;
+	memcpy(out->key, prefix, plen);
+
+	if (meta_reader_read(xr->kvrd, out->key + plen, key.size)) {
+		free(out);
+		return NULL;
+	}
+
+	return out;
+fail_alloc:
+	perror("allocating xattr key");
+	return NULL;
+}
+
+sqfs_xattr_value_t *xattr_reader_read_value(xattr_reader_t *xr,
+					    const sqfs_xattr_entry_t *key)
+{
+	size_t offset, new_offset, size;
+	sqfs_xattr_value_t value, *out;
+	uint64_t ref, start, new_start;
+
+	if (meta_reader_read(xr->kvrd, &value, sizeof(value)))
+		return NULL;
+
+	if (key->type & SQUASHFS_XATTR_FLAG_OOL) {
+		if (meta_reader_read(xr->kvrd, &ref, sizeof(ref)))
+			return NULL;
+
+		meta_reader_get_position(xr->kvrd, &start, &offset);
+
+		new_start = xr->xattr_start + (ref >> 16);
+		new_offset = ref & 0xFFFF;
+
+		if (new_start > xr->super->bytes_used) {
+			fputs("OOL xattr reference points past end of "
+			      "filesystem\n", stderr);
+			return NULL;
+		}
+
+		if (new_offset >= SQFS_META_BLOCK_SIZE) {
+			fputs("OOL xattr reference points outside "
+			      "metadata block\n", stderr);
+			return NULL;
+		}
+
+		if (meta_reader_seek(xr->kvrd, new_start, new_offset))
+			return NULL;
+	}
+
+	value.size = le32toh(value.size);
+
+	if (SZ_ADD_OV(sizeof(*out), value.size, &size) ||
+	    SZ_ADD_OV(size, 1, &size)) {
+		errno = EOVERFLOW;
+		goto fail_alloc;
+	}
+
+	out = calloc(1, size);
+	if (out == NULL)
+		goto fail_alloc;
+
+	*out = value;
+
+	if (meta_reader_read(xr->kvrd, out->value, value.size))
+		goto fail;
+
+	if (key->type & SQUASHFS_XATTR_FLAG_OOL) {
+		if (meta_reader_seek(xr->kvrd, start, offset))
+			goto fail;
+	}
+
+	return out;
+fail_alloc:
+	perror("allocating xattr value");
+	return NULL;
+fail:
+	free(out);
+	return NULL;
+}
+
+int xattr_reader_seek_kv(xattr_reader_t *xr, const sqfs_xattr_id_t *desc)
+{
+	uint32_t offset = desc->xattr & 0xFFFF;
+	uint64_t block = xr->xattr_start + (desc->xattr >> 16);
+
+	return meta_reader_seek(xr->kvrd, block, offset);
+}
+
+int xattr_reader_get_desc(xattr_reader_t *xr, uint32_t idx,
+			  sqfs_xattr_id_t *desc)
+{
+	size_t block, offset;
+
+	memset(desc, 0, sizeof(*desc));
+
+	if (idx == 0xFFFFFFFF)
+		return 0;
+
+	if (xr->kvrd == NULL || xr->idrd == NULL) {
+		if (idx != 0)
+			goto fail_bounds;
+		return 0;
+	}
+
+	if (idx >= xr->num_ids)
+		goto fail_bounds;
+
+	offset = (idx * sizeof(*desc)) % SQFS_META_BLOCK_SIZE;
+	block = (idx * sizeof(*desc)) / SQFS_META_BLOCK_SIZE;
+
+	if (meta_reader_seek(xr->idrd, xr->id_block_starts[block], offset))
+		return -1;
+
+	if (meta_reader_read(xr->idrd, desc, sizeof(*desc)))
+		return -1;
+
+	desc->xattr = le64toh(desc->xattr);
+	desc->count = le32toh(desc->count);
+	desc->size = le32toh(desc->size);
+	return 0;
+fail_bounds:
+	fprintf(stderr, "Tried to access out of bounds "
+		"xattr index: 0x%08X\n", idx);
+	return -1;
+}
+
+void xattr_reader_destroy(xattr_reader_t *xr)
+{
+	if (xr->kvrd != NULL)
+		meta_reader_destroy(xr->kvrd);
+
+	if (xr->idrd != NULL)
+		meta_reader_destroy(xr->idrd);
+
+	free(xr->id_block_starts);
+	free(xr);
+}
+
+xattr_reader_t *xattr_reader_create(int sqfsfd, sqfs_super_t *super,
+				    compressor_t *cmp)
+{
+	xattr_reader_t *xr = calloc(1, sizeof(*xr));
+
+	if (xr == NULL) {
+		perror("creating xattr reader");
+		return NULL;
+	}
+
+	if (super->flags & SQFS_FLAG_NO_XATTRS)
+		return xr;
+
+	if (super->xattr_id_table_start == 0xFFFFFFFFFFFFFFFF)
+		return xr;
+
+	if (get_id_block_locations(xr, sqfsfd, super))
+		goto fail;
+
+	xr->idrd = meta_reader_create(sqfsfd, cmp,
+				      super->id_table_start,
+				      super->bytes_used);
+	if (xr->idrd == NULL)
+		goto fail;
+
+	xr->kvrd = meta_reader_create(sqfsfd, cmp,
+				      super->id_table_start,
+				      super->bytes_used);
+	if (xr->kvrd == NULL)
+		goto fail;
+
+	xr->super = super;
+	return xr;
+fail:
+	xattr_reader_destroy(xr);
+	return NULL;
+}
diff --git a/lib/sqfshelper/deserialize_fstree.c b/lib/sqfshelper/deserialize_fstree.c
index c418b16..98c59fb 100644
--- a/lib/sqfshelper/deserialize_fstree.c
+++ b/lib/sqfshelper/deserialize_fstree.c
@@ -9,7 +9,6 @@
 #include "sqfs/meta_reader.h"
 #include "sqfs/dir.h"
 
-#include "xattr_reader.h"
 #include "highlevel.h"
 
 #include <stdlib.h>
diff --git a/lib/sqfshelper/xattr_reader.c b/lib/sqfshelper/xattr_reader.c
index c13358d..2cf1114 100644
--- a/lib/sqfshelper/xattr_reader.c
+++ b/lib/sqfshelper/xattr_reader.c
@@ -6,9 +6,7 @@
  */
 #include "config.h"
 
-#include "sqfs/meta_reader.h"
-#include "sqfs/xattr.h"
-#include "xattr_reader.h"
+#include "highlevel.h"
 #include "util.h"
 
 #include <assert.h>
@@ -17,226 +15,6 @@
 #include <stdio.h>
 #include <errno.h>
 
-struct xattr_reader_t {
-	uint64_t xattr_start;
-
-	size_t num_id_blocks;
-	size_t num_ids;
-
-	uint64_t *id_block_starts;
-
-	meta_reader_t *idrd;
-	meta_reader_t *kvrd;
-	sqfs_super_t *super;
-};
-
-static int get_id_block_locations(xattr_reader_t *xr, int sqfsfd,
-				  sqfs_super_t *super)
-{
-	sqfs_xattr_id_table_t idtbl;
-	size_t i;
-
-	if (super->xattr_id_table_start >= super->bytes_used) {
-		fputs("xattr ID location table is after end of filesystem\n",
-		      stderr);
-		return -1;
-	}
-
-	if (read_data_at("reading xattr ID location table",
-			 super->xattr_id_table_start,
-			 sqfsfd, &idtbl, sizeof(idtbl))) {
-		return -1;
-	}
-
-	xr->xattr_start = le64toh(idtbl.xattr_table_start);
-	xr->num_ids = le32toh(idtbl.xattr_ids);
-	xr->num_id_blocks =
-		(xr->num_ids * sizeof(sqfs_xattr_id_t)) / SQFS_META_BLOCK_SIZE;
-
-	if ((xr->num_ids * sizeof(sqfs_xattr_id_t)) % SQFS_META_BLOCK_SIZE)
-		xr->num_id_blocks += 1;
-
-	xr->id_block_starts = alloc_array(sizeof(uint64_t), xr->num_id_blocks);
-	if (xr->id_block_starts == NULL) {
-		perror("allocating xattr ID location table");
-		return -1;
-	}
-
-	if (read_data_at("reading xattr ID block locations",
-			 super->xattr_id_table_start + sizeof(idtbl),
-			 sqfsfd, xr->id_block_starts,
-			 sizeof(uint64_t) * xr->num_id_blocks)) {
-		goto fail;
-	}
-
-	for (i = 0; i < xr->num_id_blocks; ++i) {
-		xr->id_block_starts[i] = le64toh(xr->id_block_starts[i]);
-
-		if (xr->id_block_starts[i] > super->bytes_used) {
-			fputs("found xattr ID block that is past "
-			      "end of filesystem\n", stderr);
-			goto fail;
-		}
-	}
-
-	return 0;
-fail:
-	free(xr->id_block_starts);
-	xr->id_block_starts = NULL;
-	return -1;
-}
-
-static int get_xattr_desc(xattr_reader_t *xr, uint32_t idx,
-			  sqfs_xattr_id_t *desc)
-{
-	size_t block, offset;
-
-	if (idx >= xr->num_ids) {
-		fprintf(stderr, "Tried to access out of bounds "
-			"xattr index: 0x%08X\n", idx);
-		return -1;
-	}
-
-	offset = (idx * sizeof(*desc)) % SQFS_META_BLOCK_SIZE;
-	block = (idx * sizeof(*desc)) / SQFS_META_BLOCK_SIZE;
-
-	if (meta_reader_seek(xr->idrd, xr->id_block_starts[block], offset))
-		return -1;
-
-	if (meta_reader_read(xr->idrd, desc, sizeof(*desc)))
-		return -1;
-
-	desc->xattr = le64toh(desc->xattr);
-	desc->count = le32toh(desc->count);
-	desc->size = le32toh(desc->size);
-
-	if ((desc->xattr & 0xFFFF) >= SQFS_META_BLOCK_SIZE) {
-		fputs("Found xattr ID record pointing outside "
-		      "metadata block\n", stderr);
-		return -1;
-	}
-
-	if ((xr->xattr_start + (desc->xattr >> 16)) >= xr->super->bytes_used) {
-		fputs("Found xattr ID record pointing past "
-		      "end of filesystem\n", stderr);
-		return -1;
-	}
-
-	return 0;
-}
-
-static sqfs_xattr_entry_t *read_key(xattr_reader_t *xr)
-{
-	sqfs_xattr_entry_t key, *out;
-	const char *prefix;
-	size_t plen, total;
-
-	if (meta_reader_read(xr->kvrd, &key, sizeof(key)))
-		return NULL;
-
-	key.type = le16toh(key.type);
-	key.size = le16toh(key.size);
-
-	prefix = sqfs_get_xattr_prefix(key.type & SQUASHFS_XATTR_PREFIX_MASK);
-	if (prefix == NULL) {
-		fprintf(stderr, "found unknown xattr type %u\n",
-			key.type & SQUASHFS_XATTR_PREFIX_MASK);
-		return NULL;
-	}
-
-	plen = strlen(prefix);
-
-	if (SZ_ADD_OV(plen, key.size, &total) || SZ_ADD_OV(total, 1, &total) ||
-	    SZ_ADD_OV(sizeof(*out), total, &total)) {
-		errno = EOVERFLOW;
-		goto fail_alloc;
-	}
-
-	out = calloc(1, total);
-	if (out == NULL) {
-		goto fail_alloc;
-	}
-
-	*out = key;
-	memcpy(out->key, prefix, plen);
-
-	if (meta_reader_read(xr->kvrd, out->key + plen, key.size)) {
-		free(out);
-		return NULL;
-	}
-
-	return out;
-fail_alloc:
-	perror("allocating xattr key");
-	return NULL;
-}
-
-static sqfs_xattr_value_t *read_value(xattr_reader_t *xr,
-				      const sqfs_xattr_entry_t *key)
-{
-	size_t offset, new_offset, size;
-	sqfs_xattr_value_t value, *out;
-	uint64_t ref, start, new_start;
-
-	if (meta_reader_read(xr->kvrd, &value, sizeof(value)))
-		return NULL;
-
-	if (key->type & SQUASHFS_XATTR_FLAG_OOL) {
-		if (meta_reader_read(xr->kvrd, &ref, sizeof(ref)))
-			return NULL;
-
-		meta_reader_get_position(xr->kvrd, &start, &offset);
-
-		new_start = xr->xattr_start + (ref >> 16);
-		new_offset = ref & 0xFFFF;
-
-		if (new_start > xr->super->bytes_used) {
-			fputs("OOL xattr reference points past end of "
-			      "filesystem\n", stderr);
-			return NULL;
-		}
-
-		if (new_offset >= SQFS_META_BLOCK_SIZE) {
-			fputs("OOL xattr reference points outside "
-			      "metadata block\n", stderr);
-			return NULL;
-		}
-
-		if (meta_reader_seek(xr->kvrd, new_start, new_offset))
-			return NULL;
-	}
-
-	value.size = le32toh(value.size);
-
-	if (SZ_ADD_OV(sizeof(*out), value.size, &size) ||
-	    SZ_ADD_OV(size, 1, &size)) {
-		errno = EOVERFLOW;
-		goto fail_alloc;
-	}
-
-	out = calloc(1, size);
-	if (out == NULL)
-		goto fail_alloc;
-
-	*out = value;
-
-	if (meta_reader_read(xr->kvrd, out->value, value.size))
-		goto fail;
-
-	if (key->type & SQUASHFS_XATTR_FLAG_OOL) {
-		if (meta_reader_seek(xr->kvrd, start, offset))
-			goto fail;
-	}
-
-	return out;
-fail_alloc:
-	perror("allocating xattr value");
-	return NULL;
-fail:
-	free(out);
-	return NULL;
-}
-
 static int restore_kv_pairs(xattr_reader_t *xr, fstree_t *fs,
 			    tree_node_t *node)
 {
@@ -245,17 +23,12 @@ static int restore_kv_pairs(xattr_reader_t *xr, fstree_t *fs,
 	sqfs_xattr_value_t *val;
 	int ret;
 
-	if (meta_reader_seek(xr->kvrd, node->xattr->block,
-			     node->xattr->offset)) {
-		return -1;
-	}
-
 	for (i = 0; i < node->xattr->num_attr; ++i) {
-		key = read_key(xr);
+		key = xattr_reader_read_key(xr);
 		if (key == NULL)
 			return -1;
 
-		val = read_value(xr, key);
+		val = xattr_reader_read_value(xr, key);
 		if (val == NULL)
 			goto fail_key;
 
@@ -302,12 +75,6 @@ int xattr_reader_restore_node(xattr_reader_t *xr, fstree_t *fs,
 	sqfs_xattr_id_t desc;
 	tree_xattr_t *it;
 
-	if (xr->kvrd == NULL || xr->idrd == NULL)
-		return 0;
-
-	if (xattr == 0xFFFFFFFF)
-		return 0;
-
 	for (it = fs->xattr; it != NULL; it = it->next) {
 		if (it->index == xattr) {
 			node->xattr = it;
@@ -315,9 +82,12 @@ int xattr_reader_restore_node(xattr_reader_t *xr, fstree_t *fs,
 		}
 	}
 
-	if (get_xattr_desc(xr, xattr, &desc))
+	if (xattr_reader_get_desc(xr, xattr, &desc))
 		return -1;
 
+	if (desc.count == 0 || desc.size == 0)
+		return 0;
+
 	node->xattr = alloc_flex(sizeof(*node->xattr),
 				 sizeof(node->xattr->attr[0]), desc.count);
 	if (node->xattr == NULL) {
@@ -327,12 +97,13 @@ int xattr_reader_restore_node(xattr_reader_t *xr, fstree_t *fs,
 
 	node->xattr->num_attr = desc.count;
 	node->xattr->max_attr = desc.count;
-	node->xattr->block = xr->xattr_start + (desc.xattr >> 16);
-	node->xattr->offset = desc.xattr & 0xFFFF;
 	node->xattr->size = desc.size;
 	node->xattr->index = xattr;
 	node->xattr->owner = node;
 
+	if (xattr_reader_seek_kv(xr, &desc))
+		return -1;
+
 	if (restore_kv_pairs(xr, fs, node)) {
 		free(node->xattr);
 		return -1;
@@ -342,53 +113,3 @@ int xattr_reader_restore_node(xattr_reader_t *xr, fstree_t *fs,
 	fs->xattr = node->xattr;
 	return 0;
 }
-
-void xattr_reader_destroy(xattr_reader_t *xr)
-{
-	if (xr->kvrd != NULL)
-		meta_reader_destroy(xr->kvrd);
-
-	if (xr->idrd != NULL)
-		meta_reader_destroy(xr->idrd);
-
-	free(xr->id_block_starts);
-	free(xr);
-}
-
-xattr_reader_t *xattr_reader_create(int sqfsfd, sqfs_super_t *super,
-				    compressor_t *cmp)
-{
-	xattr_reader_t *xr = calloc(1, sizeof(*xr));
-
-	if (xr == NULL) {
-		perror("creating xattr reader");
-		return NULL;
-	}
-
-	if (super->flags & SQFS_FLAG_NO_XATTRS)
-		return xr;
-
-	if (super->xattr_id_table_start == 0xFFFFFFFFFFFFFFFF)
-		return xr;
-
-	if (get_id_block_locations(xr, sqfsfd, super))
-		goto fail;
-
-	xr->idrd = meta_reader_create(sqfsfd, cmp,
-				      super->id_table_start,
-				      super->bytes_used);
-	if (xr->idrd == NULL)
-		goto fail;
-
-	xr->kvrd = meta_reader_create(sqfsfd, cmp,
-				      super->id_table_start,
-				      super->bytes_used);
-	if (xr->kvrd == NULL)
-		goto fail;
-
-	xr->super = super;
-	return xr;
-fail:
-	xattr_reader_destroy(xr);
-	return NULL;
-}