dir-item.c
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/*
* BTRFS filesystem implementation for U-Boot
*
* 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include "btrfs.h"
static int verify_dir_item(struct btrfs_dir_item *item, u32 start, u32 total)
{
u16 max_len = BTRFS_NAME_LEN;
u32 end;
if (item->type >= BTRFS_FT_MAX) {
printf("%s: invalid dir item type: %i\n", __func__, item->type);
return 1;
}
if (item->type == BTRFS_FT_XATTR)
max_len = 255; /* XATTR_NAME_MAX */
end = start + sizeof(*item) + item->name_len;
if (item->name_len > max_len || end > total) {
printf("%s: invalid dir item name len: %u\n", __func__,
item->name_len);
return 1;
}
return 0;
}
static struct btrfs_dir_item *
btrfs_match_dir_item_name(struct btrfs_path *path, const char *name,
int name_len)
{
struct btrfs_dir_item *item;
u32 total_len, cur = 0, this_len;
const char *name_ptr;
item = btrfs_path_item_ptr(path, struct btrfs_dir_item);
total_len = btrfs_path_item_size(path);
while (cur < total_len) {
btrfs_dir_item_to_cpu(item);
this_len = sizeof(*item) + item->name_len + item->data_len;
name_ptr = (const char *) (item + 1);
if (verify_dir_item(item, cur, total_len))
return NULL;
if (item->name_len == name_len && !memcmp(name_ptr, name,
name_len))
return item;
cur += this_len;
item = (struct btrfs_dir_item *) ((u8 *) item + this_len);
}
return NULL;
}
int btrfs_lookup_dir_item(const struct btrfs_root *root, u64 dir,
const char *name, int name_len,
struct btrfs_dir_item *item)
{
struct btrfs_path path;
struct btrfs_key key;
struct btrfs_dir_item *res = NULL;
key.objectid = dir;
key.type = BTRFS_DIR_ITEM_KEY;
key.offset = btrfs_name_hash(name, name_len);
if (btrfs_search_tree(root, &key, &path))
return -1;
if (btrfs_comp_keys_type(&key, btrfs_path_leaf_key(&path)))
goto out;
res = btrfs_match_dir_item_name(&path, name, name_len);
if (res)
*item = *res;
out:
btrfs_free_path(&path);
return res ? 0 : -1;
}
int btrfs_readdir(const struct btrfs_root *root, u64 dir,
btrfs_readdir_callback_t callback)
{
struct btrfs_path path;
struct btrfs_key key, *found_key;
struct btrfs_dir_item *item;
int res = 0;
key.objectid = dir;
key.type = BTRFS_DIR_INDEX_KEY;
key.offset = 0;
if (btrfs_search_tree(root, &key, &path))
return -1;
do {
found_key = btrfs_path_leaf_key(&path);
if (btrfs_comp_keys_type(&key, found_key))
break;
item = btrfs_path_item_ptr(&path, struct btrfs_dir_item);
btrfs_dir_item_to_cpu(item);
if (verify_dir_item(item, 0, sizeof(*item) + item->name_len))
continue;
if (item->type == BTRFS_FT_XATTR)
continue;
if (callback(root, item))
break;
} while (!(res = btrfs_next_slot(&path)));
btrfs_free_path(&path);
return res < 0 ? -1 : 0;
}