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1da177e4 LT |
1 | /* |
2 | * linux/fs/isofs/namei.c | |
3 | * | |
4 | * (C) 1992 Eric Youngdale Modified for ISO 9660 filesystem. | |
5 | * | |
6 | * (C) 1991 Linus Torvalds - minix filesystem | |
7 | */ | |
8 | ||
1da177e4 LT |
9 | #include <linux/config.h> /* Joliet? */ |
10 | #include <linux/smp_lock.h> | |
94f2f715 | 11 | #include "isofs.h" |
1da177e4 LT |
12 | |
13 | /* | |
14 | * ok, we cannot use strncmp, as the name is not in our data space. | |
15 | * Thus we'll have to use isofs_match. No big problem. Match also makes | |
16 | * some sanity tests. | |
17 | */ | |
18 | static int | |
19 | isofs_cmp(struct dentry * dentry, const char * compare, int dlen) | |
20 | { | |
21 | struct qstr qstr; | |
22 | ||
23 | if (!compare) | |
24 | return 1; | |
25 | ||
26 | /* check special "." and ".." files */ | |
27 | if (dlen == 1) { | |
28 | /* "." */ | |
29 | if (compare[0] == 0) { | |
30 | if (!dentry->d_name.len) | |
31 | return 0; | |
32 | compare = "."; | |
33 | } else if (compare[0] == 1) { | |
34 | compare = ".."; | |
35 | dlen = 2; | |
36 | } | |
37 | } | |
38 | ||
39 | qstr.name = compare; | |
40 | qstr.len = dlen; | |
41 | return dentry->d_op->d_compare(dentry, &dentry->d_name, &qstr); | |
42 | } | |
43 | ||
44 | /* | |
45 | * isofs_find_entry() | |
46 | * | |
47 | * finds an entry in the specified directory with the wanted name. It | |
48 | * returns the inode number of the found entry, or 0 on error. | |
49 | */ | |
50 | static unsigned long | |
51 | isofs_find_entry(struct inode *dir, struct dentry *dentry, | |
52 | unsigned long *block_rv, unsigned long* offset_rv, | |
53 | char * tmpname, struct iso_directory_record * tmpde) | |
54 | { | |
55 | unsigned long bufsize = ISOFS_BUFFER_SIZE(dir); | |
56 | unsigned char bufbits = ISOFS_BUFFER_BITS(dir); | |
57 | unsigned long block, f_pos, offset, block_saved, offset_saved; | |
58 | struct buffer_head * bh = NULL; | |
59 | struct isofs_sb_info *sbi = ISOFS_SB(dir->i_sb); | |
60 | ||
61 | if (!ISOFS_I(dir)->i_first_extent) | |
62 | return 0; | |
63 | ||
64 | f_pos = 0; | |
65 | offset = 0; | |
66 | block = 0; | |
67 | ||
68 | while (f_pos < dir->i_size) { | |
69 | struct iso_directory_record * de; | |
70 | int de_len, match, i, dlen; | |
71 | char *dpnt; | |
72 | ||
73 | if (!bh) { | |
74 | bh = isofs_bread(dir, block); | |
75 | if (!bh) | |
76 | return 0; | |
77 | } | |
78 | ||
79 | de = (struct iso_directory_record *) (bh->b_data + offset); | |
80 | ||
81 | de_len = *(unsigned char *) de; | |
82 | if (!de_len) { | |
83 | brelse(bh); | |
84 | bh = NULL; | |
85 | f_pos = (f_pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1); | |
86 | block = f_pos >> bufbits; | |
87 | offset = 0; | |
88 | continue; | |
89 | } | |
90 | ||
91 | block_saved = bh->b_blocknr; | |
92 | offset_saved = offset; | |
93 | offset += de_len; | |
94 | f_pos += de_len; | |
95 | ||
96 | /* Make sure we have a full directory entry */ | |
97 | if (offset >= bufsize) { | |
98 | int slop = bufsize - offset + de_len; | |
99 | memcpy(tmpde, de, slop); | |
100 | offset &= bufsize - 1; | |
101 | block++; | |
102 | brelse(bh); | |
103 | bh = NULL; | |
104 | if (offset) { | |
105 | bh = isofs_bread(dir, block); | |
106 | if (!bh) | |
107 | return 0; | |
108 | memcpy((void *) tmpde + slop, bh->b_data, offset); | |
109 | } | |
110 | de = tmpde; | |
111 | } | |
112 | ||
113 | dlen = de->name_len[0]; | |
114 | dpnt = de->name; | |
115 | ||
116 | if (sbi->s_rock && | |
117 | ((i = get_rock_ridge_filename(de, tmpname, dir)))) { | |
118 | dlen = i; /* possibly -1 */ | |
119 | dpnt = tmpname; | |
120 | #ifdef CONFIG_JOLIET | |
121 | } else if (sbi->s_joliet_level) { | |
122 | dlen = get_joliet_filename(de, tmpname, dir); | |
123 | dpnt = tmpname; | |
124 | #endif | |
125 | } else if (sbi->s_mapping == 'a') { | |
126 | dlen = get_acorn_filename(de, tmpname, dir); | |
127 | dpnt = tmpname; | |
128 | } else if (sbi->s_mapping == 'n') { | |
129 | dlen = isofs_name_translate(de, tmpname, dir); | |
130 | dpnt = tmpname; | |
131 | } | |
132 | ||
133 | /* | |
134 | * Skip hidden or associated files unless unhide is set | |
135 | */ | |
136 | match = 0; | |
137 | if (dlen > 0 && | |
138 | (!(de->flags[-sbi->s_high_sierra] & 5) | |
139 | || sbi->s_unhide == 'y')) | |
140 | { | |
141 | match = (isofs_cmp(dentry,dpnt,dlen) == 0); | |
142 | } | |
143 | if (match) { | |
144 | isofs_normalize_block_and_offset(de, | |
145 | &block_saved, | |
146 | &offset_saved); | |
147 | *block_rv = block_saved; | |
148 | *offset_rv = offset_saved; | |
149 | if (bh) brelse(bh); | |
150 | return 1; | |
151 | } | |
152 | } | |
153 | if (bh) brelse(bh); | |
154 | return 0; | |
155 | } | |
156 | ||
157 | struct dentry *isofs_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd) | |
158 | { | |
159 | int found; | |
160 | unsigned long block, offset; | |
161 | struct inode *inode; | |
162 | struct page *page; | |
163 | ||
164 | dentry->d_op = dir->i_sb->s_root->d_op; | |
165 | ||
166 | page = alloc_page(GFP_USER); | |
167 | if (!page) | |
168 | return ERR_PTR(-ENOMEM); | |
169 | ||
170 | lock_kernel(); | |
171 | found = isofs_find_entry(dir, dentry, | |
172 | &block, &offset, | |
173 | page_address(page), | |
174 | 1024 + page_address(page)); | |
175 | __free_page(page); | |
176 | ||
177 | inode = NULL; | |
178 | if (found) { | |
179 | inode = isofs_iget(dir->i_sb, block, offset); | |
180 | if (!inode) { | |
181 | unlock_kernel(); | |
182 | return ERR_PTR(-EACCES); | |
183 | } | |
184 | } | |
185 | unlock_kernel(); | |
186 | if (inode) | |
187 | return d_splice_alias(inode, dentry); | |
188 | d_add(dentry, inode); | |
189 | return NULL; | |
190 | } |