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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2017-2018 HUAWEI, Inc.
4 * https://www.huawei.com/
5 * Copyright (C) 2022, Alibaba Cloud
6 */
7#include "internal.h"
8
9static int erofs_fill_dentries(struct inode *dir, struct dir_context *ctx,
10 void *dentry_blk, struct erofs_dirent *de,
11 unsigned int nameoff, unsigned int maxsize)
12{
13 const struct erofs_dirent *end = dentry_blk + nameoff;
14
15 while (de < end) {
16 const char *de_name;
17 unsigned int de_namelen;
18 unsigned char d_type;
19
20 d_type = fs_ftype_to_dtype(de->file_type);
21
22 nameoff = le16_to_cpu(de->nameoff);
23 de_name = (char *)dentry_blk + nameoff;
24
25 /* the last dirent in the block? */
26 if (de + 1 >= end)
27 de_namelen = strnlen(de_name, maxsize - nameoff);
28 else
29 de_namelen = le16_to_cpu(de[1].nameoff) - nameoff;
30
31 /* a corrupted entry is found */
32 if (nameoff + de_namelen > maxsize ||
33 de_namelen > EROFS_NAME_LEN) {
34 erofs_err(dir->i_sb, "bogus dirent @ nid %llu",
35 EROFS_I(dir)->nid);
36 DBG_BUGON(1);
37 return -EFSCORRUPTED;
38 }
39
40 if (!dir_emit(ctx, de_name, de_namelen,
41 le64_to_cpu(de->nid), d_type))
42 return 1;
43 ++de;
44 ctx->pos += sizeof(struct erofs_dirent);
45 }
46 return 0;
47}
48
49static int erofs_readdir(struct file *f, struct dir_context *ctx)
50{
51 struct inode *dir = file_inode(f);
52 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
53 struct super_block *sb = dir->i_sb;
54 unsigned long bsz = sb->s_blocksize;
55 const size_t dirsize = i_size_read(dir);
56 unsigned int i = erofs_blknr(sb, ctx->pos);
57 unsigned int ofs = erofs_blkoff(sb, ctx->pos);
58 int err = 0;
59 bool initial = true;
60
61 buf.inode = dir;
62 while (ctx->pos < dirsize) {
63 struct erofs_dirent *de;
64 unsigned int nameoff, maxsize;
65
66 de = erofs_bread(&buf, i, EROFS_KMAP);
67 if (IS_ERR(de)) {
68 erofs_err(sb, "fail to readdir of logical block %u of nid %llu",
69 i, EROFS_I(dir)->nid);
70 err = PTR_ERR(de);
71 break;
72 }
73
74 nameoff = le16_to_cpu(de->nameoff);
75 if (nameoff < sizeof(struct erofs_dirent) || nameoff >= bsz) {
76 erofs_err(sb, "invalid de[0].nameoff %u @ nid %llu",
77 nameoff, EROFS_I(dir)->nid);
78 err = -EFSCORRUPTED;
79 break;
80 }
81
82 maxsize = min_t(unsigned int, dirsize - ctx->pos + ofs, bsz);
83
84 /* search dirents at the arbitrary position */
85 if (initial) {
86 initial = false;
87
88 ofs = roundup(ofs, sizeof(struct erofs_dirent));
89 ctx->pos = erofs_pos(sb, i) + ofs;
90 if (ofs >= nameoff)
91 goto skip_this;
92 }
93
94 err = erofs_fill_dentries(dir, ctx, de, (void *)de + ofs,
95 nameoff, maxsize);
96 if (err)
97 break;
98skip_this:
99 ctx->pos = erofs_pos(sb, i) + maxsize;
100 ++i;
101 ofs = 0;
102 }
103 erofs_put_metabuf(&buf);
104 return err < 0 ? err : 0;
105}
106
107const struct file_operations erofs_dir_fops = {
108 .llseek = generic_file_llseek,
109 .read = generic_read_dir,
110 .iterate_shared = erofs_readdir,
111};
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2017-2018 HUAWEI, Inc.
4 * https://www.huawei.com/
5 * Created by Gao Xiang <gaoxiang25@huawei.com>
6 */
7#include "internal.h"
8
9static 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 erofs_dbg("found dirent %s de_len %u d_type %d", dbg_namebuf,
20 de_namelen, d_type);
21#endif
22}
23
24static int erofs_fill_dentries(struct inode *dir, struct dir_context *ctx,
25 void *dentry_blk, unsigned int *ofs,
26 unsigned int nameoff, unsigned int maxsize)
27{
28 struct erofs_dirent *de = dentry_blk + *ofs;
29 const struct erofs_dirent *end = dentry_blk + nameoff;
30
31 while (de < end) {
32 const char *de_name;
33 unsigned int de_namelen;
34 unsigned char d_type;
35
36 d_type = fs_ftype_to_dtype(de->file_type);
37
38 nameoff = le16_to_cpu(de->nameoff);
39 de_name = (char *)dentry_blk + nameoff;
40
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;
46
47 /* a corrupted entry is found */
48 if (nameoff + de_namelen > maxsize ||
49 de_namelen > EROFS_NAME_LEN) {
50 erofs_err(dir->i_sb, "bogus dirent @ nid %llu",
51 EROFS_I(dir)->nid);
52 DBG_BUGON(1);
53 return -EFSCORRUPTED;
54 }
55
56 debug_one_dentry(d_type, de_name, de_namelen);
57 if (!dir_emit(ctx, de_name, de_namelen,
58 le64_to_cpu(de->nid), d_type))
59 /* stopped by some reason */
60 return 1;
61 ++de;
62 *ofs += sizeof(struct erofs_dirent);
63 }
64 *ofs = maxsize;
65 return 0;
66}
67
68static 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);
73 unsigned int i = ctx->pos / EROFS_BLKSIZ;
74 unsigned int ofs = ctx->pos % EROFS_BLKSIZ;
75 int err = 0;
76 bool initial = true;
77
78 while (ctx->pos < dirsize) {
79 struct page *dentry_page;
80 struct erofs_dirent *de;
81 unsigned int nameoff, maxsize;
82
83 dentry_page = read_mapping_page(mapping, i, NULL);
84 if (dentry_page == ERR_PTR(-ENOMEM)) {
85 err = -ENOMEM;
86 break;
87 } else if (IS_ERR(dentry_page)) {
88 erofs_err(dir->i_sb,
89 "fail to readdir of logical block %u of nid %llu",
90 i, EROFS_I(dir)->nid);
91 err = -EFSCORRUPTED;
92 break;
93 }
94
95 de = (struct erofs_dirent *)kmap(dentry_page);
96
97 nameoff = le16_to_cpu(de->nameoff);
98
99 if (nameoff < sizeof(struct erofs_dirent) ||
100 nameoff >= PAGE_SIZE) {
101 erofs_err(dir->i_sb,
102 "invalid de[0].nameoff %u @ nid %llu",
103 nameoff, EROFS_I(dir)->nid);
104 err = -EFSCORRUPTED;
105 goto skip_this;
106 }
107
108 maxsize = min_t(unsigned int,
109 dirsize - ctx->pos + ofs, PAGE_SIZE);
110
111 /* search dirents at the arbitrary position */
112 if (initial) {
113 initial = false;
114
115 ofs = roundup(ofs, sizeof(struct erofs_dirent));
116 if (ofs >= nameoff)
117 goto skip_this;
118 }
119
120 err = erofs_fill_dentries(dir, ctx, de, &ofs,
121 nameoff, maxsize);
122skip_this:
123 kunmap(dentry_page);
124
125 put_page(dentry_page);
126
127 ctx->pos = blknr_to_addr(i) + ofs;
128
129 if (err)
130 break;
131 ++i;
132 ofs = 0;
133 }
134 return err < 0 ? err : 0;
135}
136
137const struct file_operations erofs_dir_fops = {
138 .llseek = generic_file_llseek,
139 .read = generic_read_dir,
140 .iterate_shared = erofs_readdir,
141};
142