Cleanup: split libsquashfs xattr writer code

This commit moves the libsquashfs xattr related code into a sub
directory and splits the xattr writer code up into several files.
No actual code is changed.

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

1 files changed, 342 insertions, 0 deletions

diff --git a/lib/sqfs/xattr/xattr_writer_flush.c b/lib/sqfs/xattr/xattr_writer_flush.c
new file mode 100644
index 0000000..9b3de30
--- /dev/null
+++ b/lib/sqfs/xattr/xattr_writer_flush.c
@@ -0,0 +1,342 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * xattr_writer_flush.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "xattr_writer.h"
+
+static const char *hexmap = "0123456789ABCDEF";
+
+static void *from_base32(const char *input, size_t *size_out)
+{
+	sqfs_u8 lo, hi, *out, *ptr;
+	size_t len;
+
+	len = strlen(input);
+	*size_out = len / 2;
+
+	out = malloc(*size_out);
+	if (out == NULL)
+		return NULL;
+
+	ptr = out;
+
+	while (*input != '\0') {
+		lo = strchr(hexmap, *(input++)) - hexmap;
+		hi = strchr(hexmap, *(input++)) - hexmap;
+
+		*(ptr++) = lo | (hi << 4);
+	}
+
+	return out;
+}
+
+static sqfs_s32 write_key(sqfs_meta_writer_t *mw, const char *key,
+			  bool value_is_ool)
+{
+	sqfs_xattr_entry_t kent;
+	int type, err;
+	size_t len;
+
+	type = sqfs_get_xattr_prefix_id(key);
+	assert(type >= 0);
+
+	key = strchr(key, '.');
+	assert(key != NULL);
+	++key;
+	len = strlen(key);
+
+	if (value_is_ool)
+		type |= SQFS_XATTR_FLAG_OOL;
+
+	memset(&kent, 0, sizeof(kent));
+	kent.type = htole16(type);
+	kent.size = htole16(len);
+
+	err = sqfs_meta_writer_append(mw, &kent, sizeof(kent));
+	if (err)
+		return err;
+
+	err = sqfs_meta_writer_append(mw, key, len);
+	if (err)
+		return err;
+
+	return sizeof(kent) + len;
+}
+
+static sqfs_s32 write_value(sqfs_meta_writer_t *mw, const char *value_str,
+			    sqfs_u64 *value_ref_out)
+{
+	sqfs_xattr_value_t vent;
+	sqfs_u32 offset;
+	sqfs_u64 block;
+	size_t size;
+	void *value;
+	int err;
+
+	value = from_base32(value_str, &size);
+	if (value == NULL)
+		return SQFS_ERROR_ALLOC;
+
+	memset(&vent, 0, sizeof(vent));
+	vent.size = htole32(size);
+
+	sqfs_meta_writer_get_position(mw, &block, &offset);
+	*value_ref_out = (block << 16) | (offset & 0xFFFF);
+
+	err = sqfs_meta_writer_append(mw, &vent, sizeof(vent));
+	if (err)
+		goto fail;
+
+	err = sqfs_meta_writer_append(mw, value, size);
+	if (err)
+		goto fail;
+
+	free(value);
+	return sizeof(vent) + size;
+fail:
+	free(value);
+	return err;
+}
+
+static sqfs_s32 write_value_ool(sqfs_meta_writer_t *mw, sqfs_u64 location)
+{
+	sqfs_xattr_value_t vent;
+	sqfs_u64 ref;
+	int err;
+
+	memset(&vent, 0, sizeof(vent));
+	vent.size = htole32(sizeof(location));
+	ref = htole64(location);
+
+	err = sqfs_meta_writer_append(mw, &vent, sizeof(vent));
+	if (err)
+		return err;
+
+	err = sqfs_meta_writer_append(mw, &ref, sizeof(ref));
+	if (err)
+		return err;
+
+	return sizeof(vent) + sizeof(ref);
+}
+
+static bool should_store_ool(const char *val_str, size_t refcount)
+{
+	if (refcount < 2)
+		return false;
+
+	/*
+	  Storing in line needs this many bytes: refcount * len
+
+	  Storing out-of-line needs this many: len + (refcount - 1) * 8
+
+	  Out-of-line prefereable iff refcount > 1 and:
+	      refcount * len > len + (refcount - 1) * 8
+	   => refcount * len - len > (refcount - 1) * 8
+	   => (refcount - 1) * len > (refcount - 1) * 8
+	   => len > 8
+	 */
+	return (strlen(val_str) / 2) > sizeof(sqfs_u64);
+}
+
+static int write_block_pairs(sqfs_xattr_writer_t *xwr, sqfs_meta_writer_t *mw,
+			     kv_block_desc_t *blk, sqfs_u64 *ool_locations)
+{
+	sqfs_u32 key_idx, val_idx;
+	const char *key_str, *value_str;
+	sqfs_s32 diff, total = 0;
+	size_t i, refcount;
+	sqfs_u64 ref;
+
+	for (i = 0; i < blk->count; ++i) {
+		key_idx = GET_KEY(xwr->kv_pairs[blk->start + i]);
+		val_idx = GET_VALUE(xwr->kv_pairs[blk->start + i]);
+
+		key_str = str_table_get_string(&xwr->keys, key_idx);
+		value_str = str_table_get_string(&xwr->values, val_idx);
+
+		if (ool_locations[val_idx] == 0xFFFFFFFFFFFFFFFFUL) {
+			diff = write_key(mw, key_str, false);
+			if (diff < 0)
+				return diff;
+			total += diff;
+
+			diff = write_value(mw, value_str, &ref);
+			if (diff < 0)
+				return diff;
+			total += diff;
+
+			refcount = str_table_get_ref_count(&xwr->values,
+							   val_idx);
+
+			if (should_store_ool(value_str, refcount))
+				ool_locations[val_idx] = ref;
+		} else {
+			diff = write_key(mw, key_str, true);
+			if (diff < 0)
+				return diff;
+			total += diff;
+
+			diff = write_value_ool(mw, ool_locations[val_idx]);
+			if (diff < 0)
+				return diff;
+			total += diff;
+		}
+	}
+
+	return total;
+}
+
+static int write_kv_pairs(sqfs_xattr_writer_t *xwr, sqfs_meta_writer_t *mw)
+{
+	sqfs_u64 block, *ool_locations;
+	kv_block_desc_t *blk;
+	sqfs_u32 offset;
+	sqfs_s32 size;
+	size_t i;
+
+	ool_locations = alloc_array(sizeof(ool_locations[0]),
+				    xwr->values.num_strings);
+	if (ool_locations == NULL)
+		return SQFS_ERROR_ALLOC;
+
+	for (i = 0; i < xwr->values.num_strings; ++i)
+		ool_locations[i] = 0xFFFFFFFFFFFFFFFFUL;
+
+	for (blk = xwr->kv_blocks; blk != NULL; blk = blk->next) {
+		sqfs_meta_writer_get_position(mw, &block, &offset);
+		blk->start_ref = (block << 16) | (offset & 0xFFFF);
+
+		size = write_block_pairs(xwr, mw, blk, ool_locations);
+		if (size < 0) {
+			free(ool_locations);
+			return size;
+		}
+
+		blk->size_bytes = size;
+	}
+
+	free(ool_locations);
+	return sqfs_meta_writer_flush(mw);
+}
+
+static int write_id_table(sqfs_xattr_writer_t *xwr, sqfs_meta_writer_t *mw,
+			  sqfs_u64 *locations)
+{
+	sqfs_xattr_id_t id_ent;
+	kv_block_desc_t *blk;
+	sqfs_u32 offset;
+	sqfs_u64 block;
+	size_t i = 0;
+	int err;
+
+	locations[i++] = 0;
+
+	for (blk = xwr->kv_blocks; blk != NULL; blk = blk->next) {
+		memset(&id_ent, 0, sizeof(id_ent));
+		id_ent.xattr = htole64(blk->start_ref);
+		id_ent.count = htole32(blk->count);
+		id_ent.size = htole32(blk->size_bytes);
+
+		err = sqfs_meta_writer_append(mw, &id_ent, sizeof(id_ent));
+		if (err)
+			return err;
+
+		sqfs_meta_writer_get_position(mw, &block, &offset);
+		if (block != locations[i - 1])
+			locations[i++] = block;
+	}
+
+	return sqfs_meta_writer_flush(mw);
+}
+
+static int write_location_table(sqfs_xattr_writer_t *xwr, sqfs_u64 kv_start,
+				sqfs_file_t *file, const sqfs_super_t *super,
+				sqfs_u64 *locations, size_t loc_count)
+{
+	sqfs_xattr_id_table_t idtbl;
+	int err;
+
+	memset(&idtbl, 0, sizeof(idtbl));
+	idtbl.xattr_table_start = htole64(kv_start);
+	idtbl.xattr_ids = htole32(xwr->num_blocks);
+
+	err = file->write_at(file, super->xattr_id_table_start,
+			     &idtbl, sizeof(idtbl));
+	if (err)
+		return err;
+
+	return file->write_at(file, super->xattr_id_table_start + sizeof(idtbl),
+			      locations, sizeof(locations[0]) * loc_count);
+}
+
+static int alloc_location_table(sqfs_xattr_writer_t *xwr, sqfs_u64 **tbl_out,
+				size_t *szout)
+{
+	sqfs_u64 *locations;
+	size_t size, count;
+
+	if (SZ_MUL_OV(xwr->num_blocks, sizeof(sqfs_xattr_id_t), &size))
+		return SQFS_ERROR_OVERFLOW;
+
+	count = size / SQFS_META_BLOCK_SIZE;
+	if (size % SQFS_META_BLOCK_SIZE)
+		++count;
+
+	locations = alloc_array(sizeof(sqfs_u64), count);
+	if (locations == NULL)
+		return SQFS_ERROR_ALLOC;
+
+	*tbl_out = locations;
+	*szout = count;
+	return 0;
+}
+
+int sqfs_xattr_writer_flush(sqfs_xattr_writer_t *xwr, sqfs_file_t *file,
+			    sqfs_super_t *super, sqfs_compressor_t *cmp)
+{
+	sqfs_u64 *locations = NULL, kv_start, id_start;
+	sqfs_meta_writer_t *mw;
+	size_t i, count;
+	int err;
+
+	if (xwr->num_pairs == 0 || xwr->num_blocks == 0) {
+		super->xattr_id_table_start = 0xFFFFFFFFFFFFFFFFUL;
+		super->flags |= SQFS_FLAG_NO_XATTRS;
+		return 0;
+	}
+
+	mw = sqfs_meta_writer_create(file, cmp, 0);
+	if (mw == NULL)
+		return SQFS_ERROR_ALLOC;
+
+	kv_start = file->get_size(file);
+	err = write_kv_pairs(xwr, mw);
+	if (err)
+		goto out;
+
+	sqfs_meta_writer_reset(mw);
+
+	id_start = file->get_size(file);
+	err = alloc_location_table(xwr, &locations, &count);
+	if (err)
+		goto out;
+
+	err = write_id_table(xwr, mw, locations);
+	if (err)
+		goto out;
+
+	super->xattr_id_table_start = file->get_size(file);
+	super->flags &= ~SQFS_FLAG_NO_XATTRS;
+
+	for (i = 0; i < count; ++i)
+		locations[i] = htole64(locations[i] + id_start);
+
+	err = write_location_table(xwr, kv_start, file, super,
+				   locations, count);
+out:
+	free(locations);
+	sqfs_destroy(mw);
+	return err;
+}