1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * BTRFS filesystem implementation for U-Boot
4 *
5 * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
6 */
7
8 #include "btrfs.h"
9 #include "disk-io.h"
10
verify_dir_item(struct btrfs_root * root,struct extent_buffer * leaf,struct btrfs_dir_item * dir_item)11 static int verify_dir_item(struct btrfs_root *root,
12 struct extent_buffer *leaf,
13 struct btrfs_dir_item *dir_item)
14 {
15 u16 namelen = BTRFS_NAME_LEN;
16 u8 type = btrfs_dir_type(leaf, dir_item);
17
18 if (type == BTRFS_FT_XATTR)
19 namelen = XATTR_NAME_MAX;
20
21 if (btrfs_dir_name_len(leaf, dir_item) > namelen) {
22 fprintf(stderr, "invalid dir item name len: %u\n",
23 (unsigned)btrfs_dir_data_len(leaf, dir_item));
24 return 1;
25 }
26
27 /* BTRFS_MAX_XATTR_SIZE is the same for all dir items */
28 if ((btrfs_dir_data_len(leaf, dir_item) +
29 btrfs_dir_name_len(leaf, dir_item)) >
30 BTRFS_MAX_XATTR_SIZE(root->fs_info)) {
31 fprintf(stderr, "invalid dir item name + data len: %u + %u\n",
32 (unsigned)btrfs_dir_name_len(leaf, dir_item),
33 (unsigned)btrfs_dir_data_len(leaf, dir_item));
34 return 1;
35 }
36
37 return 0;
38 }
39
btrfs_match_dir_item_name(struct btrfs_root * root,struct btrfs_path * path,const char * name,int name_len)40 struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
41 struct btrfs_path *path,
42 const char *name, int name_len)
43 {
44 struct btrfs_dir_item *dir_item;
45 unsigned long name_ptr;
46 u32 total_len;
47 u32 cur = 0;
48 u32 this_len;
49 struct extent_buffer *leaf;
50
51 leaf = path->nodes[0];
52 dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
53 total_len = btrfs_item_size_nr(leaf, path->slots[0]);
54 if (verify_dir_item(root, leaf, dir_item))
55 return NULL;
56
57 while(cur < total_len) {
58 this_len = sizeof(*dir_item) +
59 btrfs_dir_name_len(leaf, dir_item) +
60 btrfs_dir_data_len(leaf, dir_item);
61 if (this_len > (total_len - cur)) {
62 fprintf(stderr, "invalid dir item size\n");
63 return NULL;
64 }
65
66 name_ptr = (unsigned long)(dir_item + 1);
67
68 if (btrfs_dir_name_len(leaf, dir_item) == name_len &&
69 memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0)
70 return dir_item;
71
72 cur += this_len;
73 dir_item = (struct btrfs_dir_item *)((char *)dir_item +
74 this_len);
75 }
76 return NULL;
77 }
78
btrfs_lookup_dir_item(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * path,u64 dir,const char * name,int name_len,int mod)79 struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
80 struct btrfs_root *root,
81 struct btrfs_path *path, u64 dir,
82 const char *name, int name_len,
83 int mod)
84 {
85 int ret;
86 struct btrfs_key key;
87 int ins_len = mod < 0 ? -1 : 0;
88 int cow = mod != 0;
89 struct btrfs_key found_key;
90 struct extent_buffer *leaf;
91
92 key.objectid = dir;
93 key.type = BTRFS_DIR_ITEM_KEY;
94
95 key.offset = btrfs_name_hash(name, name_len);
96
97 ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
98 if (ret < 0)
99 return ERR_PTR(ret);
100 if (ret > 0) {
101 if (path->slots[0] == 0)
102 return NULL;
103 path->slots[0]--;
104 }
105
106 leaf = path->nodes[0];
107 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
108
109 if (found_key.objectid != dir ||
110 found_key.type != BTRFS_DIR_ITEM_KEY ||
111 found_key.offset != key.offset)
112 return NULL;
113
114 return btrfs_match_dir_item_name(root, path, name, name_len);
115 }
116
btrfs_iter_dir(struct btrfs_root * root,u64 ino,btrfs_iter_dir_callback_t callback)117 int btrfs_iter_dir(struct btrfs_root *root, u64 ino,
118 btrfs_iter_dir_callback_t callback)
119 {
120 struct btrfs_path path;
121 struct btrfs_key key;
122 int ret;
123
124 btrfs_init_path(&path);
125 key.objectid = ino;
126 key.type = BTRFS_DIR_INDEX_KEY;
127 key.offset = 0;
128
129 ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
130 if (ret < 0)
131 return ret;
132 /* Should not happen */
133 if (ret == 0) {
134 ret = -EUCLEAN;
135 goto out;
136 }
137 if (path.slots[0] >= btrfs_header_nritems(path.nodes[0])) {
138 ret = btrfs_next_leaf(root, &path);
139 if (ret < 0)
140 goto out;
141 if (ret > 0) {
142 ret = 0;
143 goto out;
144 }
145 }
146 do {
147 struct btrfs_dir_item *di;
148
149 btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
150 if (key.objectid != ino || key.type != BTRFS_DIR_INDEX_KEY)
151 break;
152 di = btrfs_item_ptr(path.nodes[0], path.slots[0],
153 struct btrfs_dir_item);
154 if (verify_dir_item(root, path.nodes[0], di)) {
155 ret = -EUCLEAN;
156 goto out;
157 }
158 ret = callback(root, path.nodes[0], di);
159 if (ret < 0)
160 goto out;
161 } while (!(ret = btrfs_next_item(root, &path)));
162
163 if (ret > 0)
164 ret = 0;
165 out:
166 btrfs_release_path(&path);
167 return ret;
168 }
169