fs/btrfs/dir-item.c

   1 /*
   2  * BTRFS filesystem implementation for U-Boot
   3  *
   4  * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include "btrfs.h"
  10
  11 static int verify_dir_item(struct btrfs_dir_item *item, u32 start, u32 total)
  12 {
  13         u16 max_len = BTRFS_NAME_LEN;
  14         u32 end;
  15
  16         if (item->type >= BTRFS_FT_MAX) {
  17                 printf("%s: invalid dir item type: %i\n", __func__, item->type);
  18                 return 1;
  19         }
  20
  21         if (item->type == BTRFS_FT_XATTR)
  22                 max_len = 255; /* XATTR_NAME_MAX */
  23
  24         end = start + sizeof(*item) + item->name_len;
  25         if (item->name_len > max_len || end > total) {
  26                 printf("%s: invalid dir item name len: %u\n", __func__,
  27                        item->name_len);
  28                 return 1;
  29         }
  30
  31         return 0;
  32 }
  33
  34 static struct btrfs_dir_item *
  35 btrfs_match_dir_item_name(struct btrfs_path *path, const char *name,
  36                           int name_len)
  37 {
  38         struct btrfs_dir_item *item;
  39         u32 total_len, cur = 0, this_len;
  40         const char *name_ptr;
  41
  42         item = btrfs_path_item_ptr(path, struct btrfs_dir_item);
  43
  44         total_len = btrfs_path_item_size(path);
  45
  46         while (cur < total_len) {
  47                 btrfs_dir_item_to_cpu(item);
  48                 this_len = sizeof(*item) + item->name_len + item->data_len;
  49                 name_ptr = (const char *) (item + 1);
  50
  51                 if (verify_dir_item(item, cur, total_len))
  52                         return NULL;
  53                 if (item->name_len == name_len && !memcmp(name_ptr, name,
  54                                                           name_len))
  55                         return item;
  56
  57                 cur += this_len;
  58                 item = (struct btrfs_dir_item *) ((u8 *) item + this_len);
  59         }
  60
  61         return NULL;
  62 }
  63
  64 int btrfs_lookup_dir_item(const struct btrfs_root *root, u64 dir,
  65                           const char *name, int name_len,
  66                           struct btrfs_dir_item *item)
  67 {
  68         struct btrfs_path path;
  69         struct btrfs_key key;
  70         struct btrfs_dir_item *res = NULL;
  71
  72         key.objectid = dir;
  73         key.type = BTRFS_DIR_ITEM_KEY;
  74         key.offset = btrfs_name_hash(name, name_len);
  75
  76         if (btrfs_search_tree(root, &key, &path))
  77                 return -1;
  78
  79         if (btrfs_comp_keys_type(&key, btrfs_path_leaf_key(&path)))
  80                 goto out;
  81
  82         res = btrfs_match_dir_item_name(&path, name, name_len);
  83         if (res)
  84                 *item = *res;
  85 out:
  86         btrfs_free_path(&path);
  87         return res ? 0 : -1;
  88 }
  89
  90 int btrfs_readdir(const struct btrfs_root *root, u64 dir,
  91                   btrfs_readdir_callback_t callback)
  92 {
  93         struct btrfs_path path;
  94         struct btrfs_key key, *found_key;
  95         struct btrfs_dir_item *item;
  96         int res = 0;
  97
  98         key.objectid = dir;
  99         key.type = BTRFS_DIR_INDEX_KEY;
 100         key.offset = 0;
 101
 102         if (btrfs_search_tree(root, &key, &path))
 103                 return -1;
 104
 105         do {
 106                 found_key = btrfs_path_leaf_key(&path);
 107                 if (btrfs_comp_keys_type(&key, found_key))
 108                         break;
 109
 110                 item = btrfs_path_item_ptr(&path, struct btrfs_dir_item);
 111                 btrfs_dir_item_to_cpu(item);
 112
 113                 if (verify_dir_item(item, 0, sizeof(*item) + item->name_len))
 114                         continue;
 115                 if (item->type == BTRFS_FT_XATTR)
 116                         continue;
 117
 118                 if (callback(root, item))
 119                         break;
 120         } while (!(res = btrfs_next_slot(&path)));
 121
 122         btrfs_free_path(&path);
 123
 124         return res < 0 ? -1 : 0;
 125 }