Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * symlink.c | |
3 | * | |
4 | * PURPOSE | |
5 | * Symlink handling routines for the OSTA-UDF(tm) filesystem. | |
6 | * | |
1da177e4 LT |
7 | * COPYRIGHT |
8 | * This file is distributed under the terms of the GNU General Public | |
9 | * License (GPL). Copies of the GPL can be obtained from: | |
10 | * ftp://prep.ai.mit.edu/pub/gnu/GPL | |
11 | * Each contributing author retains all rights to their own work. | |
12 | * | |
13 | * (C) 1998-2001 Ben Fennema | |
28de7948 | 14 | * (C) 1999 Stelias Computing Inc |
1da177e4 LT |
15 | * |
16 | * HISTORY | |
17 | * | |
18 | * 04/16/99 blf Created. | |
19 | * | |
20 | */ | |
21 | ||
22 | #include "udfdecl.h" | |
e973606c | 23 | #include <linux/uaccess.h> |
1da177e4 LT |
24 | #include <linux/errno.h> |
25 | #include <linux/fs.h> | |
1da177e4 LT |
26 | #include <linux/time.h> |
27 | #include <linux/mm.h> | |
28 | #include <linux/stat.h> | |
1da177e4 | 29 | #include <linux/pagemap.h> |
1da177e4 LT |
30 | #include "udf_i.h" |
31 | ||
0e5cc9a4 JK |
32 | static int udf_pc_to_char(struct super_block *sb, unsigned char *from, |
33 | int fromlen, unsigned char *to, int tolen) | |
1da177e4 LT |
34 | { |
35 | struct pathComponent *pc; | |
36 | int elen = 0; | |
0e5cc9a4 | 37 | int comp_len; |
391e8bbd | 38 | unsigned char *p = to; |
1da177e4 | 39 | |
0e5cc9a4 JK |
40 | /* Reserve one byte for terminating \0 */ |
41 | tolen--; | |
cb00ea35 | 42 | while (elen < fromlen) { |
1da177e4 | 43 | pc = (struct pathComponent *)(from + elen); |
e237ec37 | 44 | elen += sizeof(struct pathComponent); |
cb00ea35 CG |
45 | switch (pc->componentType) { |
46 | case 1: | |
fef2e9f3 JK |
47 | /* |
48 | * Symlink points to some place which should be agreed | |
49 | * upon between originator and receiver of the media. Ignore. | |
50 | */ | |
e237ec37 JK |
51 | if (pc->lengthComponentIdent > 0) { |
52 | elen += pc->lengthComponentIdent; | |
fef2e9f3 | 53 | break; |
e237ec37 | 54 | } |
df561f66 | 55 | fallthrough; |
fef2e9f3 | 56 | case 2: |
0e5cc9a4 JK |
57 | if (tolen == 0) |
58 | return -ENAMETOOLONG; | |
fef2e9f3 JK |
59 | p = to; |
60 | *p++ = '/'; | |
0e5cc9a4 | 61 | tolen--; |
cb00ea35 CG |
62 | break; |
63 | case 3: | |
0e5cc9a4 JK |
64 | if (tolen < 3) |
65 | return -ENAMETOOLONG; | |
cb00ea35 CG |
66 | memcpy(p, "../", 3); |
67 | p += 3; | |
0e5cc9a4 | 68 | tolen -= 3; |
cb00ea35 CG |
69 | break; |
70 | case 4: | |
0e5cc9a4 JK |
71 | if (tolen < 2) |
72 | return -ENAMETOOLONG; | |
cb00ea35 CG |
73 | memcpy(p, "./", 2); |
74 | p += 2; | |
0e5cc9a4 | 75 | tolen -= 2; |
cb00ea35 CG |
76 | /* that would be . - just ignore */ |
77 | break; | |
78 | case 5: | |
e237ec37 JK |
79 | elen += pc->lengthComponentIdent; |
80 | if (elen > fromlen) | |
81 | return -EIO; | |
0e5cc9a4 JK |
82 | comp_len = udf_get_filename(sb, pc->componentIdent, |
83 | pc->lengthComponentIdent, | |
84 | p, tolen); | |
5ceb8b55 FF |
85 | if (comp_len < 0) |
86 | return comp_len; | |
87 | ||
0e5cc9a4 JK |
88 | p += comp_len; |
89 | tolen -= comp_len; | |
90 | if (tolen == 0) | |
91 | return -ENAMETOOLONG; | |
cb00ea35 | 92 | *p++ = '/'; |
0e5cc9a4 | 93 | tolen--; |
cb00ea35 | 94 | break; |
1da177e4 | 95 | } |
1da177e4 | 96 | } |
cb00ea35 | 97 | if (p > to + 1) |
1da177e4 LT |
98 | p[-1] = '\0'; |
99 | else | |
100 | p[0] = '\0'; | |
0e5cc9a4 | 101 | return 0; |
1da177e4 LT |
102 | } |
103 | ||
0c698cc5 | 104 | static int udf_symlink_filler(struct file *file, struct folio *folio) |
1da177e4 | 105 | { |
0c698cc5 | 106 | struct page *page = &folio->page; |
1da177e4 LT |
107 | struct inode *inode = page->mapping->host; |
108 | struct buffer_head *bh = NULL; | |
391e8bbd | 109 | unsigned char *symlink; |
15a08f51 | 110 | int err = 0; |
21fc61c7 | 111 | unsigned char *p = page_address(page); |
f33321b2 | 112 | struct udf_inode_info *iinfo = UDF_I(inode); |
1da177e4 | 113 | |
a1d47b26 JK |
114 | /* We don't support symlinks longer than one block */ |
115 | if (inode->i_size > inode->i_sb->s_blocksize) { | |
116 | err = -ENAMETOOLONG; | |
f33321b2 | 117 | goto out_unlock; |
a1d47b26 JK |
118 | } |
119 | ||
48d6d8ff | 120 | if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) { |
382a2287 | 121 | symlink = iinfo->i_data + iinfo->i_lenEAttr; |
28de7948 | 122 | } else { |
15a08f51 | 123 | bh = udf_bread(inode, 0, 0, &err); |
a1d47b26 | 124 | if (!bh) { |
15a08f51 JK |
125 | if (!err) |
126 | err = -EFSCORRUPTED; | |
f33321b2 | 127 | goto out_err; |
a1d47b26 | 128 | } |
1da177e4 LT |
129 | symlink = bh->b_data; |
130 | } | |
131 | ||
0e5cc9a4 | 132 | err = udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p, PAGE_SIZE); |
3bf25cb4 | 133 | brelse(bh); |
0e5cc9a4 | 134 | if (err) |
f33321b2 | 135 | goto out_err; |
1da177e4 | 136 | |
1da177e4 | 137 | SetPageUptodate(page); |
1da177e4 LT |
138 | unlock_page(page); |
139 | return 0; | |
28de7948 | 140 | |
f33321b2 | 141 | out_err: |
1da177e4 | 142 | SetPageError(page); |
f33321b2 | 143 | out_unlock: |
1da177e4 LT |
144 | unlock_page(page); |
145 | return err; | |
146 | } | |
147 | ||
b74d24f7 | 148 | static int udf_symlink_getattr(struct mnt_idmap *idmap, |
549c7297 CB |
149 | const struct path *path, struct kstat *stat, |
150 | u32 request_mask, unsigned int flags) | |
ad4d0532 | 151 | { |
a528d35e | 152 | struct dentry *dentry = path->dentry; |
ad4d0532 JK |
153 | struct inode *inode = d_backing_inode(dentry); |
154 | struct page *page; | |
155 | ||
b74d24f7 | 156 | generic_fillattr(&nop_mnt_idmap, inode, stat); |
ad4d0532 JK |
157 | page = read_mapping_page(inode->i_mapping, 0, NULL); |
158 | if (IS_ERR(page)) | |
159 | return PTR_ERR(page); | |
160 | /* | |
161 | * UDF uses non-trivial encoding of symlinks so i_size does not match | |
162 | * number of characters reported by readlink(2) which apparently some | |
163 | * applications expect. Also POSIX says that "The value returned in the | |
164 | * st_size field shall be the length of the contents of the symbolic | |
165 | * link, and shall not count a trailing null if one is present." So | |
166 | * let's report the length of string returned by readlink(2) for | |
167 | * st_size. | |
168 | */ | |
169 | stat->size = strlen(page_address(page)); | |
170 | put_page(page); | |
171 | ||
172 | return 0; | |
173 | } | |
174 | ||
1da177e4 LT |
175 | /* |
176 | * symlinks can't do much... | |
177 | */ | |
f5e54d6e | 178 | const struct address_space_operations udf_symlink_aops = { |
0c698cc5 | 179 | .read_folio = udf_symlink_filler, |
1da177e4 | 180 | }; |
ad4d0532 JK |
181 | |
182 | const struct inode_operations udf_symlink_inode_operations = { | |
183 | .get_link = page_get_link, | |
184 | .getattr = udf_symlink_getattr, | |
185 | }; |