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29b24f6c | 1 | // SPDX-License-Identifier: GPL-2.0-only |
3aa8ec71 | 2 | /* |
3aa8ec71 | 3 | * Copyright (C) 2017-2018 HUAWEI, Inc. |
592e7cd0 | 4 | * https://www.huawei.com/ |
3aa8ec71 | 5 | * Created by Gao Xiang <gaoxiang25@huawei.com> |
3aa8ec71 GX |
6 | */ |
7 | #include "internal.h" | |
8 | ||
33bac912 GX |
9 | static void debug_one_dentry(unsigned char d_type, const char *de_name, |
10 | unsigned int de_namelen) | |
11 | { | |
12 | #ifdef CONFIG_EROFS_FS_DEBUG | |
13 | /* since the on-disk name could not have the trailing '\0' */ | |
14 | unsigned char dbg_namebuf[EROFS_NAME_LEN + 1]; | |
15 | ||
16 | memcpy(dbg_namebuf, de_name, de_namelen); | |
17 | dbg_namebuf[de_namelen] = '\0'; | |
18 | ||
4f761fa2 GX |
19 | erofs_dbg("found dirent %s de_len %u d_type %d", dbg_namebuf, |
20 | de_namelen, d_type); | |
33bac912 GX |
21 | #endif |
22 | } | |
23 | ||
a6b9b1d5 | 24 | static int erofs_fill_dentries(struct inode *dir, struct dir_context *ctx, |
cbebe5d0 BP |
25 | void *dentry_blk, unsigned int *ofs, |
26 | unsigned int nameoff, unsigned int maxsize) | |
3aa8ec71 | 27 | { |
5c8004ce | 28 | struct erofs_dirent *de = dentry_blk + *ofs; |
3aa8ec71 GX |
29 | const struct erofs_dirent *end = dentry_blk + nameoff; |
30 | ||
3aa8ec71 GX |
31 | while (de < end) { |
32 | const char *de_name; | |
33bac912 | 33 | unsigned int de_namelen; |
3aa8ec71 | 34 | unsigned char d_type; |
3aa8ec71 | 35 | |
1d819c54 | 36 | d_type = fs_ftype_to_dtype(de->file_type); |
3aa8ec71 GX |
37 | |
38 | nameoff = le16_to_cpu(de->nameoff); | |
39 | de_name = (char *)dentry_blk + nameoff; | |
40 | ||
33bac912 GX |
41 | /* the last dirent in the block? */ |
42 | if (de + 1 >= end) | |
43 | de_namelen = strnlen(de_name, maxsize - nameoff); | |
44 | else | |
45 | de_namelen = le16_to_cpu(de[1].nameoff) - nameoff; | |
3aa8ec71 | 46 | |
8b987bca | 47 | /* a corrupted entry is found */ |
8d8a09b0 GX |
48 | if (nameoff + de_namelen > maxsize || |
49 | de_namelen > EROFS_NAME_LEN) { | |
4f761fa2 GX |
50 | erofs_err(dir->i_sb, "bogus dirent @ nid %llu", |
51 | EROFS_I(dir)->nid); | |
8b987bca | 52 | DBG_BUGON(1); |
a6b9b1d5 | 53 | return -EFSCORRUPTED; |
8b987bca | 54 | } |
3aa8ec71 | 55 | |
33bac912 | 56 | debug_one_dentry(d_type, de_name, de_namelen); |
3aa8ec71 | 57 | if (!dir_emit(ctx, de_name, de_namelen, |
019ec6c1 AS |
58 | le64_to_cpu(de->nid), d_type)) |
59 | /* stopped by some reason */ | |
3aa8ec71 GX |
60 | return 1; |
61 | ++de; | |
62 | *ofs += sizeof(struct erofs_dirent); | |
63 | } | |
64 | *ofs = maxsize; | |
65 | return 0; | |
66 | } | |
67 | ||
68 | static int erofs_readdir(struct file *f, struct dir_context *ctx) | |
69 | { | |
70 | struct inode *dir = file_inode(f); | |
71 | struct address_space *mapping = dir->i_mapping; | |
72 | const size_t dirsize = i_size_read(dir); | |
7dd68b14 TW |
73 | unsigned int i = ctx->pos / EROFS_BLKSIZ; |
74 | unsigned int ofs = ctx->pos % EROFS_BLKSIZ; | |
3aa8ec71 GX |
75 | int err = 0; |
76 | bool initial = true; | |
77 | ||
78 | while (ctx->pos < dirsize) { | |
79 | struct page *dentry_page; | |
80 | struct erofs_dirent *de; | |
7dd68b14 | 81 | unsigned int nameoff, maxsize; |
3aa8ec71 GX |
82 | |
83 | dentry_page = read_mapping_page(mapping, i, NULL); | |
acb383f1 GX |
84 | if (dentry_page == ERR_PTR(-ENOMEM)) { |
85 | err = -ENOMEM; | |
86 | break; | |
87 | } else if (IS_ERR(dentry_page)) { | |
4f761fa2 GX |
88 | erofs_err(dir->i_sb, |
89 | "fail to readdir of logical block %u of nid %llu", | |
90 | i, EROFS_I(dir)->nid); | |
acb383f1 GX |
91 | err = -EFSCORRUPTED; |
92 | break; | |
93 | } | |
3aa8ec71 | 94 | |
3aa8ec71 GX |
95 | de = (struct erofs_dirent *)kmap(dentry_page); |
96 | ||
97 | nameoff = le16_to_cpu(de->nameoff); | |
98 | ||
8d8a09b0 GX |
99 | if (nameoff < sizeof(struct erofs_dirent) || |
100 | nameoff >= PAGE_SIZE) { | |
4f761fa2 GX |
101 | erofs_err(dir->i_sb, |
102 | "invalid de[0].nameoff %u @ nid %llu", | |
103 | nameoff, EROFS_I(dir)->nid); | |
a6b9b1d5 | 104 | err = -EFSCORRUPTED; |
3aa8ec71 GX |
105 | goto skip_this; |
106 | } | |
107 | ||
7dd68b14 TW |
108 | maxsize = min_t(unsigned int, |
109 | dirsize - ctx->pos + ofs, PAGE_SIZE); | |
3aa8ec71 GX |
110 | |
111 | /* search dirents at the arbitrary position */ | |
8d8a09b0 | 112 | if (initial) { |
3aa8ec71 GX |
113 | initial = false; |
114 | ||
115 | ofs = roundup(ofs, sizeof(struct erofs_dirent)); | |
8d8a09b0 | 116 | if (ofs >= nameoff) |
3aa8ec71 GX |
117 | goto skip_this; |
118 | } | |
119 | ||
a6b9b1d5 GX |
120 | err = erofs_fill_dentries(dir, ctx, de, &ofs, |
121 | nameoff, maxsize); | |
3aa8ec71 GX |
122 | skip_this: |
123 | kunmap(dentry_page); | |
124 | ||
3aa8ec71 GX |
125 | put_page(dentry_page); |
126 | ||
127 | ctx->pos = blknr_to_addr(i) + ofs; | |
128 | ||
8d8a09b0 | 129 | if (err) |
3aa8ec71 GX |
130 | break; |
131 | ++i; | |
132 | ofs = 0; | |
133 | } | |
134 | return err < 0 ? err : 0; | |
135 | } | |
136 | ||
137 | const struct file_operations erofs_dir_fops = { | |
138 | .llseek = generic_file_llseek, | |
139 | .read = generic_read_dir, | |
bee15682 | 140 | .iterate_shared = erofs_readdir, |
3aa8ec71 GX |
141 | }; |
142 |