Commit | Line | Data |
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29b24f6c | 1 | // SPDX-License-Identifier: GPL-2.0-only |
3aa8ec71 | 2 | /* |
3aa8ec71 GX |
3 | * Copyright (C) 2017-2018 HUAWEI, Inc. |
4 | * http://www.huawei.com/ | |
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 | ||
19 | debugln("found dirent %s de_len %u d_type %d", dbg_namebuf, | |
20 | de_namelen, d_type); | |
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 */ |
33bac912 GX |
48 | if (unlikely(nameoff + de_namelen > maxsize || |
49 | de_namelen > EROFS_NAME_LEN)) { | |
a6b9b1d5 | 50 | errln("bogus dirent @ nid %llu", EROFS_V(dir)->nid); |
8b987bca | 51 | DBG_BUGON(1); |
a6b9b1d5 | 52 | return -EFSCORRUPTED; |
8b987bca | 53 | } |
3aa8ec71 | 54 | |
33bac912 | 55 | debug_one_dentry(d_type, de_name, de_namelen); |
3aa8ec71 | 56 | if (!dir_emit(ctx, de_name, de_namelen, |
019ec6c1 AS |
57 | le64_to_cpu(de->nid), d_type)) |
58 | /* stopped by some reason */ | |
3aa8ec71 GX |
59 | return 1; |
60 | ++de; | |
61 | *ofs += sizeof(struct erofs_dirent); | |
62 | } | |
63 | *ofs = maxsize; | |
64 | return 0; | |
65 | } | |
66 | ||
67 | static int erofs_readdir(struct file *f, struct dir_context *ctx) | |
68 | { | |
69 | struct inode *dir = file_inode(f); | |
70 | struct address_space *mapping = dir->i_mapping; | |
71 | const size_t dirsize = i_size_read(dir); | |
7dd68b14 TW |
72 | unsigned int i = ctx->pos / EROFS_BLKSIZ; |
73 | unsigned int ofs = ctx->pos % EROFS_BLKSIZ; | |
3aa8ec71 GX |
74 | int err = 0; |
75 | bool initial = true; | |
76 | ||
77 | while (ctx->pos < dirsize) { | |
78 | struct page *dentry_page; | |
79 | struct erofs_dirent *de; | |
7dd68b14 | 80 | unsigned int nameoff, maxsize; |
3aa8ec71 GX |
81 | |
82 | dentry_page = read_mapping_page(mapping, i, NULL); | |
acb383f1 GX |
83 | if (dentry_page == ERR_PTR(-ENOMEM)) { |
84 | err = -ENOMEM; | |
85 | break; | |
86 | } else if (IS_ERR(dentry_page)) { | |
87 | errln("fail to readdir of logical block %u of nid %llu", | |
88 | i, EROFS_V(dir)->nid); | |
89 | err = -EFSCORRUPTED; | |
90 | break; | |
91 | } | |
3aa8ec71 | 92 | |
3aa8ec71 GX |
93 | de = (struct erofs_dirent *)kmap(dentry_page); |
94 | ||
95 | nameoff = le16_to_cpu(de->nameoff); | |
96 | ||
97 | if (unlikely(nameoff < sizeof(struct erofs_dirent) || | |
cbebe5d0 | 98 | nameoff >= PAGE_SIZE)) { |
a6b9b1d5 GX |
99 | errln("%s, invalid de[0].nameoff %u @ nid %llu", |
100 | __func__, nameoff, EROFS_V(dir)->nid); | |
101 | err = -EFSCORRUPTED; | |
3aa8ec71 GX |
102 | goto skip_this; |
103 | } | |
104 | ||
7dd68b14 TW |
105 | maxsize = min_t(unsigned int, |
106 | dirsize - ctx->pos + ofs, PAGE_SIZE); | |
3aa8ec71 GX |
107 | |
108 | /* search dirents at the arbitrary position */ | |
109 | if (unlikely(initial)) { | |
110 | initial = false; | |
111 | ||
112 | ofs = roundup(ofs, sizeof(struct erofs_dirent)); | |
113 | if (unlikely(ofs >= nameoff)) | |
114 | goto skip_this; | |
115 | } | |
116 | ||
a6b9b1d5 GX |
117 | err = erofs_fill_dentries(dir, ctx, de, &ofs, |
118 | nameoff, maxsize); | |
3aa8ec71 GX |
119 | skip_this: |
120 | kunmap(dentry_page); | |
121 | ||
3aa8ec71 GX |
122 | put_page(dentry_page); |
123 | ||
124 | ctx->pos = blknr_to_addr(i) + ofs; | |
125 | ||
126 | if (unlikely(err)) | |
127 | break; | |
128 | ++i; | |
129 | ofs = 0; | |
130 | } | |
131 | return err < 0 ? err : 0; | |
132 | } | |
133 | ||
134 | const struct file_operations erofs_dir_fops = { | |
135 | .llseek = generic_file_llseek, | |
136 | .read = generic_read_dir, | |
bee15682 | 137 | .iterate_shared = erofs_readdir, |
3aa8ec71 GX |
138 | }; |
139 |