Move write_xattr to libsqfs.a

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

2 files changed, 206 insertions, 1 deletions

diff --git a/lib/Makemodule.am b/lib/Makemodule.am
index 1b99a05..3c1ef12 100644
--- a/lib/Makemodule.am
+++ b/lib/Makemodule.am
@@ -22,7 +22,7 @@ libsquashfs_a_SOURCES += lib/sqfs/write_dir.c lib/sqfs/write_inode.c
 libsquashfs_a_SOURCES += lib/sqfs/serialize_fstree.c
 libsquashfs_a_SOURCES += lib/sqfs/tree_node_from_inode.c
 libsquashfs_a_SOURCES += lib/sqfs/deserialize_fstree.c
-libsquashfs_a_SOURCES += lib/sqfs/data_writer.c
+libsquashfs_a_SOURCES += lib/sqfs/data_writer.c lib/sqfs/write_xattr.c
 libsquashfs_a_SOURCES += include/data_writer.h
 libsquashfs_a_SOURCES += include/frag_reader.h
 
diff --git a/lib/sqfs/write_xattr.c b/lib/sqfs/write_xattr.c
new file mode 100644
index 0000000..b6198b4
--- /dev/null
+++ b/lib/sqfs/write_xattr.c
@@ -0,0 +1,205 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include "meta_writer.h"
+#include "highlevel.h"
+#include "util.h"
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+static const struct {
+	const char *prefix;
+	E_SQFS_XATTR_TYPE type;
+} xattr_types[] = {
+	{ "user.", SQUASHFS_XATTR_USER },
+	{ "trusted.", SQUASHFS_XATTR_TRUSTED },
+	{ "security.", SQUASHFS_XATTR_SECURITY },
+};
+
+static int get_prefix(const char *key)
+{
+	size_t i, len;
+
+	for (i = 0; i < sizeof(xattr_types) / sizeof(xattr_types[0]); ++i) {
+		len = strlen(xattr_types[i].prefix);
+
+		if (strncmp(key, xattr_types[i].prefix, len) == 0 &&
+		    strlen(key) > len) {
+			return xattr_types[i].type;
+		}
+	}
+
+	fprintf(stderr, "unknown xattr key '%s'\n", key);
+	return -1;
+}
+
+static int write_pair(meta_writer_t *mw, const char *key, const char *value)
+{
+	sqfs_xattr_entry_t kent;
+	sqfs_xattr_value_t vent;
+	int type;
+
+	type = get_prefix(key);
+	if (type < 0)
+		return -1;
+
+	key = strchr(key, '.');
+	assert(key != NULL);
+	++key;
+
+	kent.type = htole16(type);
+	kent.size = htole16(strlen(key));
+
+	if (meta_writer_append(mw, &kent, sizeof(kent)))
+		return -1;
+	if (meta_writer_append(mw, key, strlen(key)))
+		return -1;
+
+	vent.size = htole32(strlen(value));
+
+	if (meta_writer_append(mw, &vent, sizeof(vent)))
+		return -1;
+	if (meta_writer_append(mw, value, strlen(value)))
+		return -1;
+
+	return 0;
+}
+
+static int write_kv_pairs(fstree_t *fs, meta_writer_t *mw, tree_xattr_t *xattr)
+{
+	uint32_t key_idx, val_idx;
+	const char *key, *value;
+	size_t i;
+
+	for (i = 0; i < xattr->num_attr; ++i) {
+		key_idx = (xattr->ref[i] >> 32) & 0xFFFFFFFF;
+		val_idx = xattr->ref[i] & 0xFFFFFFFF;
+
+		key = str_table_get_string(&fs->xattr_keys, key_idx);
+		value = str_table_get_string(&fs->xattr_values, val_idx);
+
+		if (write_pair(mw, key, value))
+			return -1;
+
+		xattr->size += sizeof(sqfs_xattr_entry_t) + strlen(key);
+		xattr->size += sizeof(sqfs_xattr_value_t) + strlen(value);
+	}
+
+	return 0;
+}
+
+int write_xattr(int outfd, fstree_t *fs, sqfs_super_t *super,
+		compressor_t *cmp)
+{
+	uint64_t kv_start, id_start, block, *tbl;
+	size_t i = 0, count = 0, blocks;
+	sqfs_xattr_id_table_t idtbl;
+	sqfs_xattr_id_t id_ent;
+	meta_writer_t *mw;
+	tree_xattr_t *it;
+	uint32_t offset;
+	ssize_t ret;
+
+	if (fs->xattr == NULL)
+		return 0;
+
+	mw = meta_writer_create(outfd, cmp);
+	if (mw == NULL)
+		return -1;
+
+	/* write xattr key-value pairs */
+	kv_start = super->bytes_used;
+
+	for (it = fs->xattr; it != NULL; it = it->next) {
+		meta_writer_get_position(mw, &it->block, &it->offset);
+		it->size = 0;
+
+		if (write_kv_pairs(fs, mw, it))
+			goto fail_mw;
+
+		++count;
+	}
+
+	if (meta_writer_flush(mw))
+		goto fail_mw;
+
+	meta_writer_get_position(mw, &block, &offset);
+	meta_writer_reset(mw);
+
+	super->bytes_used += block;
+
+	/* allocate location table */
+	blocks = (count * sizeof(id_ent)) / SQFS_META_BLOCK_SIZE;
+
+	if ((count * sizeof(id_ent)) % SQFS_META_BLOCK_SIZE)
+		++blocks;
+
+	tbl = calloc(sizeof(uint64_t), blocks);
+
+	if (tbl == NULL) {
+		perror("generating xattr ID table");
+		goto fail_mw;
+	}
+
+	/* write ID table referring to key value pairs, record offsets */
+	id_start = 0;
+	tbl[i++] = htole64(super->bytes_used);
+
+	for (it = fs->xattr; it != NULL; it = it->next) {
+		id_ent.xattr = htole64((it->block << 16) | it->offset);
+		id_ent.count = htole32(it->num_attr);
+		id_ent.size = htole32(it->size);
+
+		if (meta_writer_append(mw, &id_ent, sizeof(id_ent)))
+			goto fail_tbl;
+
+		meta_writer_get_position(mw, &block, &offset);
+
+		if (block != id_start) {
+			id_start = block;
+			tbl[i++] = htole64(super->bytes_used + id_start);
+		}
+	}
+
+	if (meta_writer_flush(mw))
+		goto fail_tbl;
+
+	meta_writer_get_position(mw, &block, &offset);
+	super->bytes_used += block;
+
+	/* write offset table */
+	idtbl.xattr_table_start = htole64(kv_start);
+	idtbl.xattr_ids = htole32(count);
+	idtbl.unused = 0;
+
+	ret = write_retry(outfd, &idtbl, sizeof(idtbl));
+	if (ret < 0)
+		goto fail_wr;
+	if ((size_t)ret < sizeof(idtbl))
+		goto fail_trunc;
+
+	write_retry(outfd, tbl, sizeof(tbl[0]) * blocks);
+	if (ret < 0)
+		goto fail_wr;
+	if ((size_t)ret < sizeof(tbl[0]) * blocks)
+		goto fail_trunc;
+
+	super->xattr_id_table_start = super->bytes_used;
+	super->bytes_used += sizeof(idtbl) + sizeof(tbl[0]) * blocks;
+
+	free(tbl);
+	meta_writer_destroy(mw);
+	return 0;
+fail_wr:
+	perror("writing xattr ID table");
+	goto fail_tbl;
+fail_trunc:
+	fputs("writing xattr ID table: truncated write\n", stderr);
+	goto fail_tbl;
+fail_tbl:
+	free(tbl);
+fail_mw:
+	meta_writer_destroy(mw);
+	return -1;
+}