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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 <linux/buffer_head.h> |
31 | #include "udf_i.h" | |
32 | ||
0e5cc9a4 JK |
33 | static int udf_pc_to_char(struct super_block *sb, unsigned char *from, |
34 | int fromlen, unsigned char *to, int tolen) | |
1da177e4 LT |
35 | { |
36 | struct pathComponent *pc; | |
37 | int elen = 0; | |
0e5cc9a4 | 38 | int comp_len; |
391e8bbd | 39 | unsigned char *p = to; |
1da177e4 | 40 | |
0e5cc9a4 JK |
41 | /* Reserve one byte for terminating \0 */ |
42 | tolen--; | |
cb00ea35 | 43 | while (elen < fromlen) { |
1da177e4 | 44 | pc = (struct pathComponent *)(from + elen); |
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 | */ | |
51 | if (pc->lengthComponentIdent > 0) | |
52 | break; | |
53 | /* Fall through */ | |
54 | case 2: | |
0e5cc9a4 JK |
55 | if (tolen == 0) |
56 | return -ENAMETOOLONG; | |
fef2e9f3 JK |
57 | p = to; |
58 | *p++ = '/'; | |
0e5cc9a4 | 59 | tolen--; |
cb00ea35 CG |
60 | break; |
61 | case 3: | |
0e5cc9a4 JK |
62 | if (tolen < 3) |
63 | return -ENAMETOOLONG; | |
cb00ea35 CG |
64 | memcpy(p, "../", 3); |
65 | p += 3; | |
0e5cc9a4 | 66 | tolen -= 3; |
cb00ea35 CG |
67 | break; |
68 | case 4: | |
0e5cc9a4 JK |
69 | if (tolen < 2) |
70 | return -ENAMETOOLONG; | |
cb00ea35 CG |
71 | memcpy(p, "./", 2); |
72 | p += 2; | |
0e5cc9a4 | 73 | tolen -= 2; |
cb00ea35 CG |
74 | /* that would be . - just ignore */ |
75 | break; | |
76 | case 5: | |
0e5cc9a4 JK |
77 | comp_len = udf_get_filename(sb, pc->componentIdent, |
78 | pc->lengthComponentIdent, | |
79 | p, tolen); | |
80 | p += comp_len; | |
81 | tolen -= comp_len; | |
82 | if (tolen == 0) | |
83 | return -ENAMETOOLONG; | |
cb00ea35 | 84 | *p++ = '/'; |
0e5cc9a4 | 85 | tolen--; |
cb00ea35 | 86 | break; |
1da177e4 LT |
87 | } |
88 | elen += sizeof(struct pathComponent) + pc->lengthComponentIdent; | |
89 | } | |
cb00ea35 | 90 | if (p > to + 1) |
1da177e4 LT |
91 | p[-1] = '\0'; |
92 | else | |
93 | p[0] = '\0'; | |
0e5cc9a4 | 94 | return 0; |
1da177e4 LT |
95 | } |
96 | ||
97 | static int udf_symlink_filler(struct file *file, struct page *page) | |
98 | { | |
99 | struct inode *inode = page->mapping->host; | |
100 | struct buffer_head *bh = NULL; | |
391e8bbd | 101 | unsigned char *symlink; |
a1d47b26 | 102 | int err; |
391e8bbd | 103 | unsigned char *p = kmap(page); |
48d6d8ff | 104 | struct udf_inode_info *iinfo; |
4d0fb621 | 105 | uint32_t pos; |
1da177e4 | 106 | |
a1d47b26 JK |
107 | /* We don't support symlinks longer than one block */ |
108 | if (inode->i_size > inode->i_sb->s_blocksize) { | |
109 | err = -ENAMETOOLONG; | |
110 | goto out_unmap; | |
111 | } | |
112 | ||
48d6d8ff | 113 | iinfo = UDF_I(inode); |
4d0fb621 AIB |
114 | pos = udf_block_map(inode, 0); |
115 | ||
116 | down_read(&iinfo->i_data_sem); | |
48d6d8ff MS |
117 | if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) { |
118 | symlink = iinfo->i_ext.i_data + iinfo->i_lenEAttr; | |
28de7948 | 119 | } else { |
4d0fb621 | 120 | bh = sb_bread(inode->i_sb, pos); |
1da177e4 | 121 | |
a1d47b26 JK |
122 | if (!bh) { |
123 | err = -EIO; | |
124 | goto out_unlock_inode; | |
125 | } | |
1da177e4 LT |
126 | |
127 | symlink = bh->b_data; | |
128 | } | |
129 | ||
0e5cc9a4 | 130 | err = udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p, PAGE_SIZE); |
3bf25cb4 | 131 | brelse(bh); |
0e5cc9a4 JK |
132 | if (err) |
133 | goto out_unlock_inode; | |
1da177e4 | 134 | |
4d0fb621 | 135 | up_read(&iinfo->i_data_sem); |
1da177e4 LT |
136 | SetPageUptodate(page); |
137 | kunmap(page); | |
138 | unlock_page(page); | |
139 | return 0; | |
28de7948 | 140 | |
a1d47b26 | 141 | out_unlock_inode: |
4d0fb621 | 142 | up_read(&iinfo->i_data_sem); |
1da177e4 | 143 | SetPageError(page); |
a1d47b26 | 144 | out_unmap: |
1da177e4 LT |
145 | kunmap(page); |
146 | unlock_page(page); | |
147 | return err; | |
148 | } | |
149 | ||
150 | /* | |
151 | * symlinks can't do much... | |
152 | */ | |
f5e54d6e | 153 | const struct address_space_operations udf_symlink_aops = { |
28de7948 | 154 | .readpage = udf_symlink_filler, |
1da177e4 | 155 | }; |