fs/btrfs/inode.c - u-boot - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * BTRFS filesystem implementation for U-Boot
  *
  * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
  */

 #include "btrfs.h"
 #include <malloc.h>

 u64 btrfs_lookup_inode_ref(struct btrfs_root *root, u64 inr,
 			   struct btrfs_inode_ref *refp, char *name)
 {
 	struct btrfs_path path;
 	struct btrfs_key *key;
 	struct btrfs_inode_ref *ref;
 	u64 res = -1ULL;

 	key = btrfs_search_tree_key_type(root, inr, BTRFS_INODE_REF_KEY,
 					       &path);

 	if (!key)
 		return -1ULL;

 	ref = btrfs_path_item_ptr(&path, struct btrfs_inode_ref);
 	btrfs_inode_ref_to_cpu(ref);

 	if (refp)
 		*refp = *ref;

 	if (name) {
 		if (ref->name_len > BTRFS_NAME_MAX) {
 			printf("%s: inode name too long: %u\n", __func__,
 			        ref->name_len);
 			goto out;
 		}

 		memcpy(name, ref + 1, ref->name_len);
 	}

 	res = key->offset;
 out:
 	btrfs_free_path(&path);
 	return res;
 }

 int btrfs_lookup_inode(const struct btrfs_root *root,
 		       struct btrfs_key *location,
 		       struct btrfs_inode_item *item,
 		       struct btrfs_root *new_root)
 {
 	struct btrfs_root tmp_root = *root;
 	struct btrfs_path path;
 	int res = -1;

 	if (location->type == BTRFS_ROOT_ITEM_KEY) {
 		if (btrfs_find_root(location->objectid, &tmp_root, NULL))
 			return -1;

 		location->objectid = tmp_root.root_dirid;
 		location->type = BTRFS_INODE_ITEM_KEY;
 		location->offset = 0;
 	}

 	if (btrfs_search_tree(&tmp_root, location, &path))
 		return res;

 	if (btrfs_comp_keys(location, btrfs_path_leaf_key(&path)))
 		goto out;

 	if (item) {
 		*item = *btrfs_path_item_ptr(&path, struct btrfs_inode_item);
 		btrfs_inode_item_to_cpu(item);
 	}

 	if (new_root)
 		*new_root = tmp_root;

 	res = 0;

 out:
 	btrfs_free_path(&path);
 	return res;
 }

 int btrfs_readlink(const struct btrfs_root *root, u64 inr, char *target)
 {
 	struct btrfs_path path;
 	struct btrfs_key key;
 	struct btrfs_file_extent_item *extent;
 	const char *data_ptr;
 	int res = -1;

 	key.objectid = inr;
 	key.type = BTRFS_EXTENT_DATA_KEY;
 	key.offset = 0;

 	if (btrfs_search_tree(root, &key, &path))
 		return -1;

 	if (btrfs_comp_keys(&key, btrfs_path_leaf_key(&path)))
 		goto out;

 	extent = btrfs_path_item_ptr(&path, struct btrfs_file_extent_item);
 	if (extent->type != BTRFS_FILE_EXTENT_INLINE) {
 		printf("%s: Extent for symlink %llu not of INLINE type\n",
 		       __func__, inr);
 		goto out;
 	}

 	btrfs_file_extent_item_to_cpu_inl(extent);

 	if (extent->compression != BTRFS_COMPRESS_NONE) {
 		printf("%s: Symlink %llu extent data compressed!\n", __func__,
 		       inr);
 		goto out;
 	} else if (extent->encryption != 0) {
 		printf("%s: Symlink %llu extent data encrypted!\n", __func__,
 		       inr);
 		goto out;
 	} else if (extent->ram_bytes >= btrfs_info.sb.sectorsize) {
 		printf("%s: Symlink %llu extent data too long (%llu)!\n",
 		       __func__, inr, extent->ram_bytes);
 		goto out;
 	}

 	data_ptr = (const char *) extent
 		   + offsetof(struct btrfs_file_extent_item, disk_bytenr);

 	memcpy(target, data_ptr, extent->ram_bytes);
 	target[extent->ram_bytes] = '\0';
 	res = 0;
 out:
 	btrfs_free_path(&path);
 	return res;
 }

 /* inr must be a directory (for regular files with multiple hard links this
    function returns only one of the parents of the file) */
 static u64 get_parent_inode(struct btrfs_root *root, u64 inr,
 			    struct btrfs_inode_item *inode_item)
 {
 	struct btrfs_key key;
 	u64 res;

 	if (inr == BTRFS_FIRST_FREE_OBJECTID) {
 		if (root->objectid != btrfs_info.fs_root.objectid) {
 			u64 parent;
 			struct btrfs_root_ref ref;

 			parent = btrfs_lookup_root_ref(root->objectid, &ref,
 						       NULL);
 			if (parent == -1ULL)
 				return -1ULL;

 			if (btrfs_find_root(parent, root, NULL))
 				return -1ULL;

 			inr = ref.dirid;
 		}

 		if (inode_item) {
 			key.objectid = inr;
 			key.type = BTRFS_INODE_ITEM_KEY;
 			key.offset = 0;

 			if (btrfs_lookup_inode(root, &key, inode_item, NULL))
 				return -1ULL;
 		}

 		return inr;
 	}

 	res = btrfs_lookup_inode_ref(root, inr, NULL, NULL);
 	if (res == -1ULL)
 		return -1ULL;

 	if (inode_item) {
 		key.objectid = res;
 		key.type = BTRFS_INODE_ITEM_KEY;
 		key.offset = 0;

 		if (btrfs_lookup_inode(root, &key, inode_item, NULL))
 			return -1ULL;
 	}

 	return res;
 }

 static inline int next_length(const char *path)
 {
 	int res = 0;
 	while (*path != '\0' && *path != '/' && res <= BTRFS_NAME_LEN)
 		++res, ++path;
 	return res;
 }

 static inline const char *skip_current_directories(const char *cur)
 {
 	while (1) {
 		if (cur[0] == '/')
 			++cur;
 		else if (cur[0] == '.' && cur[1] == '/')
 			cur += 2;
 		else
 			break;
 	}

 	return cur;
 }

 u64 btrfs_lookup_path(struct btrfs_root *root, u64 inr, const char *path,
 		      u8 *type_p, struct btrfs_inode_item *inode_item_p,
 		      int symlink_limit)
 {
 	struct btrfs_dir_item item;
 	struct btrfs_inode_item inode_item;
 	u8 type = BTRFS_FT_DIR;
 	int len, have_inode = 0;
 	const char *cur = path;

 	if (*cur == '/') {
 		++cur;
 		inr = root->root_dirid;
 	}

 	do {
 		cur = skip_current_directories(cur);

 		len = next_length(cur);
 		if (len > BTRFS_NAME_LEN) {
 			printf("%s: Name too long at \"%.*s\"\n", __func__,
 			       BTRFS_NAME_LEN, cur);
 			return -1ULL;
 		}

 		if (len == 1 && cur[0] == '.')
 			break;

 		if (len == 2 && cur[0] == '.' && cur[1] == '.') {
 			cur += 2;
 			inr = get_parent_inode(root, inr, &inode_item);
 			if (inr == -1ULL)
 				return -1ULL;

 			type = BTRFS_FT_DIR;
 			continue;
 		}

 		if (!*cur)
 			break;

 		if (btrfs_lookup_dir_item(root, inr, cur, len, &item))
 			return -1ULL;

 		type = item.type;
 		have_inode = 1;
 		if (btrfs_lookup_inode(root, &item.location, &inode_item, root))
 			return -1ULL;

 		if (item.type == BTRFS_FT_SYMLINK && symlink_limit >= 0) {
 			char *target;

 			if (!symlink_limit) {
 				printf("%s: Too much symlinks!\n", __func__);
 				return -1ULL;
 			}

 			target = malloc(min(inode_item.size + 1,
 					    (u64) btrfs_info.sb.sectorsize));
 			if (!target)
 				return -1ULL;

 			if (btrfs_readlink(root, item.location.objectid,
 					   target)) {
 				free(target);
 				return -1ULL;
 			}

 			inr = btrfs_lookup_path(root, inr, target, &type,
 						&inode_item, symlink_limit - 1);

 			free(target);

 			if (inr == -1ULL)
 				return -1ULL;
 		} else if (item.type != BTRFS_FT_DIR && cur[len]) {
 			printf("%s: \"%.*s\" not a directory\n", __func__,
 			       (int) (cur - path + len), path);
 			return -1ULL;
 		} else {
 			inr = item.location.objectid;
 		}

 		cur += len;
 	} while (*cur);

 	if (type_p)
 		*type_p = type;

 	if (inode_item_p) {
 		if (!have_inode) {
 			struct btrfs_key key;

 			key.objectid = inr;
 			key.type = BTRFS_INODE_ITEM_KEY;
 			key.offset = 0;

 			if (btrfs_lookup_inode(root, &key, &inode_item, NULL))
 				return -1ULL;
 		}

 		*inode_item_p = inode_item;
 	}

 	return inr;
 }

 u64 btrfs_file_read(const struct btrfs_root *root, u64 inr, u64 offset,
 		    u64 size, char *buf)
 {
 	struct btrfs_path path;
 	struct btrfs_key key;
 	struct btrfs_file_extent_item *extent;
 	int res = 0;
 	u64 rd, rd_all = -1ULL;

 	key.objectid = inr;
 	key.type = BTRFS_EXTENT_DATA_KEY;
 	key.offset = offset;

 	if (btrfs_search_tree(root, &key, &path))
 		return -1ULL;

 	if (btrfs_comp_keys(&key, btrfs_path_leaf_key(&path)) < 0) {
 		if (btrfs_prev_slot(&path))
 			goto out;

 		if (btrfs_comp_keys_type(&key, btrfs_path_leaf_key(&path)))
 			goto out;
 	}

 	rd_all = 0;

 	do {
 		if (btrfs_comp_keys_type(&key, btrfs_path_leaf_key(&path)))
 			break;

 		extent = btrfs_path_item_ptr(&path,
 					     struct btrfs_file_extent_item);

 		if (extent->type == BTRFS_FILE_EXTENT_INLINE) {
 			btrfs_file_extent_item_to_cpu_inl(extent);
 			rd = btrfs_read_extent_inline(&path, extent, offset,
 						      size, buf);
 		} else {
 			btrfs_file_extent_item_to_cpu(extent);
 			rd = btrfs_read_extent_reg(&path, extent, offset, size,
 						   buf);
 		}

 		if (rd == -1ULL) {
 			printf("%s: Error reading extent\n", __func__);
 			rd_all = -1;
 			goto out;
 		}

 		offset = 0;
 		buf += rd;
 		rd_all += rd;
 		size -= rd;

 		if (!size)
 			break;
 	} while (!(res = btrfs_next_slot(&path)));

 	if (res)
 		return -1ULL;

 out:
 	btrfs_free_path(&path);
 	return rd_all;
 }
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* BTRFS filesystem implementation for U-Boot
	*
	* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
	*/

	#include "btrfs.h"
	#include <malloc.h>

	u64 btrfs_lookup_inode_ref(struct btrfs_root *root, u64 inr,
	struct btrfs_inode_ref refp, char name)
	{
	struct btrfs_path path;
	struct btrfs_key *key;
	struct btrfs_inode_ref *ref;
	u64 res = -1ULL;

	key = btrfs_search_tree_key_type(root, inr, BTRFS_INODE_REF_KEY,
	&path);

	if (!key)
	return -1ULL;

	ref = btrfs_path_item_ptr(&path, struct btrfs_inode_ref);
	btrfs_inode_ref_to_cpu(ref);

	if (refp)
	refp = ref;

	if (name) {
	if (ref->name_len > BTRFS_NAME_MAX) {
	printf("%s: inode name too long: %u\n", __func__,
	ref->name_len);
	goto out;
	}

	memcpy(name, ref + 1, ref->name_len);
	}

	res = key->offset;
	out:
	btrfs_free_path(&path);
	return res;
	}

	int btrfs_lookup_inode(const struct btrfs_root *root,
	struct btrfs_key *location,
	struct btrfs_inode_item *item,
	struct btrfs_root *new_root)
	{
	struct btrfs_root tmp_root = *root;
	struct btrfs_path path;
	int res = -1;

	if (location->type == BTRFS_ROOT_ITEM_KEY) {
	if (btrfs_find_root(location->objectid, &tmp_root, NULL))
	return -1;

	location->objectid = tmp_root.root_dirid;
	location->type = BTRFS_INODE_ITEM_KEY;
	location->offset = 0;
	}

	if (btrfs_search_tree(&tmp_root, location, &path))
	return res;

	if (btrfs_comp_keys(location, btrfs_path_leaf_key(&path)))
	goto out;

	if (item) {
	item = btrfs_path_item_ptr(&path, struct btrfs_inode_item);
	btrfs_inode_item_to_cpu(item);
	}

	if (new_root)
	*new_root = tmp_root;

	res = 0;

	out:
	btrfs_free_path(&path);
	return res;
	}

	int btrfs_readlink(const struct btrfs_root root, u64 inr, char target)
	{
	struct btrfs_path path;
	struct btrfs_key key;
	struct btrfs_file_extent_item *extent;
	const char *data_ptr;
	int res = -1;

	key.objectid = inr;
	key.type = BTRFS_EXTENT_DATA_KEY;
	key.offset = 0;

	if (btrfs_search_tree(root, &key, &path))
	return -1;

	if (btrfs_comp_keys(&key, btrfs_path_leaf_key(&path)))
	goto out;

	extent = btrfs_path_item_ptr(&path, struct btrfs_file_extent_item);
	if (extent->type != BTRFS_FILE_EXTENT_INLINE) {
	printf("%s: Extent for symlink %llu not of INLINE type\n",
	__func__, inr);
	goto out;
	}

	btrfs_file_extent_item_to_cpu_inl(extent);

	if (extent->compression != BTRFS_COMPRESS_NONE) {
	printf("%s: Symlink %llu extent data compressed!\n", __func__,
	inr);
	goto out;
	} else if (extent->encryption != 0) {
	printf("%s: Symlink %llu extent data encrypted!\n", __func__,
	inr);
	goto out;
	} else if (extent->ram_bytes >= btrfs_info.sb.sectorsize) {
	printf("%s: Symlink %llu extent data too long (%llu)!\n",
	__func__, inr, extent->ram_bytes);
	goto out;
	}

	data_ptr = (const char *) extent
	+ offsetof(struct btrfs_file_extent_item, disk_bytenr);

	memcpy(target, data_ptr, extent->ram_bytes);
	target[extent->ram_bytes] = '\0';
	res = 0;
	out:
	btrfs_free_path(&path);
	return res;
	}

	/* inr must be a directory (for regular files with multiple hard links this
	function returns only one of the parents of the file) */
	static u64 get_parent_inode(struct btrfs_root *root, u64 inr,
	struct btrfs_inode_item *inode_item)
	{
	struct btrfs_key key;
	u64 res;

	if (inr == BTRFS_FIRST_FREE_OBJECTID) {
	if (root->objectid != btrfs_info.fs_root.objectid) {
	u64 parent;
	struct btrfs_root_ref ref;

	parent = btrfs_lookup_root_ref(root->objectid, &ref,
	NULL);
	if (parent == -1ULL)
	return -1ULL;

	if (btrfs_find_root(parent, root, NULL))
	return -1ULL;

	inr = ref.dirid;
	}

	if (inode_item) {
	key.objectid = inr;
	key.type = BTRFS_INODE_ITEM_KEY;
	key.offset = 0;

	if (btrfs_lookup_inode(root, &key, inode_item, NULL))
	return -1ULL;
	}

	return inr;
	}

	res = btrfs_lookup_inode_ref(root, inr, NULL, NULL);
	if (res == -1ULL)
	return -1ULL;

	if (inode_item) {
	key.objectid = res;
	key.type = BTRFS_INODE_ITEM_KEY;
	key.offset = 0;

	if (btrfs_lookup_inode(root, &key, inode_item, NULL))
	return -1ULL;
	}

	return res;
	}

	static inline int next_length(const char *path)
	{
	int res = 0;
	while (path != '\0' && path != '/' && res <= BTRFS_NAME_LEN)
	++res, ++path;
	return res;
	}

	static inline const char skip_current_directories(const char cur)
	{
	while (1) {
	if (cur[0] == '/')
	++cur;
	else if (cur[0] == '.' && cur[1] == '/')
	cur += 2;
	else
	break;
	}

	return cur;
	}

	u64 btrfs_lookup_path(struct btrfs_root root, u64 inr, const char path,
	u8 type_p, struct btrfs_inode_item inode_item_p,
	int symlink_limit)
	{
	struct btrfs_dir_item item;
	struct btrfs_inode_item inode_item;
	u8 type = BTRFS_FT_DIR;
	int len, have_inode = 0;
	const char *cur = path;

	if (*cur == '/') {
	++cur;
	inr = root->root_dirid;
	}

	do {
	cur = skip_current_directories(cur);

	len = next_length(cur);
	if (len > BTRFS_NAME_LEN) {
	printf("%s: Name too long at \"%.*s\"\n", __func__,
	BTRFS_NAME_LEN, cur);
	return -1ULL;
	}

	if (len == 1 && cur[0] == '.')
	break;

	if (len == 2 && cur[0] == '.' && cur[1] == '.') {
	cur += 2;
	inr = get_parent_inode(root, inr, &inode_item);
	if (inr == -1ULL)
	return -1ULL;

	type = BTRFS_FT_DIR;
	continue;
	}

	if (!*cur)
	break;

	if (btrfs_lookup_dir_item(root, inr, cur, len, &item))
	return -1ULL;

	type = item.type;
	have_inode = 1;
	if (btrfs_lookup_inode(root, &item.location, &inode_item, root))
	return -1ULL;

	if (item.type == BTRFS_FT_SYMLINK && symlink_limit >= 0) {
	char *target;

	if (!symlink_limit) {
	printf("%s: Too much symlinks!\n", __func__);
	return -1ULL;
	}

	target = malloc(min(inode_item.size + 1,
	(u64) btrfs_info.sb.sectorsize));
	if (!target)
	return -1ULL;

	if (btrfs_readlink(root, item.location.objectid,
	target)) {
	free(target);
	return -1ULL;
	}

	inr = btrfs_lookup_path(root, inr, target, &type,
	&inode_item, symlink_limit - 1);

	free(target);

	if (inr == -1ULL)
	return -1ULL;
	} else if (item.type != BTRFS_FT_DIR && cur[len]) {
	printf("%s: \"%.*s\" not a directory\n", __func__,
	(int) (cur - path + len), path);
	return -1ULL;
	} else {
	inr = item.location.objectid;
	}

	cur += len;
	} while (*cur);

	if (type_p)
	*type_p = type;

	if (inode_item_p) {
	if (!have_inode) {
	struct btrfs_key key;

	key.objectid = inr;
	key.type = BTRFS_INODE_ITEM_KEY;
	key.offset = 0;

	if (btrfs_lookup_inode(root, &key, &inode_item, NULL))
	return -1ULL;
	}

	*inode_item_p = inode_item;
	}

	return inr;
	}

	u64 btrfs_file_read(const struct btrfs_root *root, u64 inr, u64 offset,
	u64 size, char *buf)
	{
	struct btrfs_path path;
	struct btrfs_key key;
	struct btrfs_file_extent_item *extent;
	int res = 0;
	u64 rd, rd_all = -1ULL;

	key.objectid = inr;
	key.type = BTRFS_EXTENT_DATA_KEY;
	key.offset = offset;

	if (btrfs_search_tree(root, &key, &path))
	return -1ULL;

	if (btrfs_comp_keys(&key, btrfs_path_leaf_key(&path)) < 0) {
	if (btrfs_prev_slot(&path))
	goto out;

	if (btrfs_comp_keys_type(&key, btrfs_path_leaf_key(&path)))
	goto out;
	}

	rd_all = 0;

	do {
	if (btrfs_comp_keys_type(&key, btrfs_path_leaf_key(&path)))
	break;

	extent = btrfs_path_item_ptr(&path,
	struct btrfs_file_extent_item);

	if (extent->type == BTRFS_FILE_EXTENT_INLINE) {
	btrfs_file_extent_item_to_cpu_inl(extent);
	rd = btrfs_read_extent_inline(&path, extent, offset,
	size, buf);
	} else {
	btrfs_file_extent_item_to_cpu(extent);
	rd = btrfs_read_extent_reg(&path, extent, offset, size,
	buf);
	}

	if (rd == -1ULL) {
	printf("%s: Error reading extent\n", __func__);
	rd_all = -1;
	goto out;
	}

	offset = 0;
	buf += rd;
	rd_all += rd;
	size -= rd;

	if (!size)
	break;
	} while (!(res = btrfs_next_slot(&path)));

	if (res)
	return -1ULL;

	out:
	btrfs_free_path(&path);
	return rd_all;
	}