Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzi...
[linux-2.6] / fs / isofs / namei.c
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
9 #include <linux/smp_lock.h>
10 #include "isofs.h"
11
12 /*
13  * ok, we cannot use strncmp, as the name is not in our data space.
14  * Thus we'll have to use isofs_match. No big problem. Match also makes
15  * some sanity tests.
16  */
17 static int
18 isofs_cmp(struct dentry *dentry, const char *compare, int dlen)
19 {
20         struct qstr qstr;
21
22         if (!compare)
23                 return 1;
24
25         /* check special "." and ".." files */
26         if (dlen == 1) {
27                 /* "." */
28                 if (compare[0] == 0) {
29                         if (!dentry->d_name.len)
30                                 return 0;
31                         compare = ".";
32                 } else if (compare[0] == 1) {
33                         compare = "..";
34                         dlen = 2;
35                 }
36         }
37
38         qstr.name = compare;
39         qstr.len = dlen;
40         return dentry->d_op->d_compare(dentry, &dentry->d_name, &qstr);
41 }
42
43 /*
44  *      isofs_find_entry()
45  *
46  * finds an entry in the specified directory with the wanted name. It
47  * returns the inode number of the found entry, or 0 on error.
48  */
49 static unsigned long
50 isofs_find_entry(struct inode *dir, struct dentry *dentry,
51         unsigned long *block_rv, unsigned long *offset_rv,
52         char *tmpname, struct iso_directory_record *tmpde)
53 {
54         unsigned long bufsize = ISOFS_BUFFER_SIZE(dir);
55         unsigned char bufbits = ISOFS_BUFFER_BITS(dir);
56         unsigned long block, f_pos, offset, block_saved, offset_saved;
57         struct buffer_head *bh = NULL;
58         struct isofs_sb_info *sbi = ISOFS_SB(dir->i_sb);
59
60         if (!ISOFS_I(dir)->i_first_extent)
61                 return 0;
62
63         f_pos = 0;
64         offset = 0;
65         block = 0;
66
67         while (f_pos < dir->i_size) {
68                 struct iso_directory_record *de;
69                 int de_len, match, i, dlen;
70                 char *dpnt;
71
72                 if (!bh) {
73                         bh = isofs_bread(dir, block);
74                         if (!bh)
75                                 return 0;
76                 }
77
78                 de = (struct iso_directory_record *) (bh->b_data + offset);
79
80                 de_len = *(unsigned char *) de;
81                 if (!de_len) {
82                         brelse(bh);
83                         bh = NULL;
84                         f_pos = (f_pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
85                         block = f_pos >> bufbits;
86                         offset = 0;
87                         continue;
88                 }
89
90                 block_saved = bh->b_blocknr;
91                 offset_saved = offset;
92                 offset += de_len;
93                 f_pos += de_len;
94
95                 /* Make sure we have a full directory entry */
96                 if (offset >= bufsize) {
97                         int slop = bufsize - offset + de_len;
98                         memcpy(tmpde, de, slop);
99                         offset &= bufsize - 1;
100                         block++;
101                         brelse(bh);
102                         bh = NULL;
103                         if (offset) {
104                                 bh = isofs_bread(dir, block);
105                                 if (!bh)
106                                         return 0;
107                                 memcpy((void *) tmpde + slop, bh->b_data, offset);
108                         }
109                         de = tmpde;
110                 }
111
112                 dlen = de->name_len[0];
113                 dpnt = de->name;
114                 /* Basic sanity check, whether name doesn't exceed dir entry */
115                 if (de_len < dlen + sizeof(struct iso_directory_record)) {
116                         printk(KERN_NOTICE "iso9660: Corrupted directory entry"
117                                " in block %lu of inode %lu\n", block,
118                                dir->i_ino);
119                         return 0;
120                 }
121
122                 if (sbi->s_rock &&
123                     ((i = get_rock_ridge_filename(de, tmpname, dir)))) {
124                         dlen = i;       /* possibly -1 */
125                         dpnt = tmpname;
126 #ifdef CONFIG_JOLIET
127                 } else if (sbi->s_joliet_level) {
128                         dlen = get_joliet_filename(de, tmpname, dir);
129                         dpnt = tmpname;
130 #endif
131                 } else if (sbi->s_mapping == 'a') {
132                         dlen = get_acorn_filename(de, tmpname, dir);
133                         dpnt = tmpname;
134                 } else if (sbi->s_mapping == 'n') {
135                         dlen = isofs_name_translate(de, tmpname, dir);
136                         dpnt = tmpname;
137                 }
138
139                 /*
140                  * Skip hidden or associated files unless hide or showassoc,
141                  * respectively, is set
142                  */
143                 match = 0;
144                 if (dlen > 0 &&
145                         (sbi->s_hide =='n' ||
146                                 (!(de->flags[-sbi->s_high_sierra] & 1))) &&
147                         (sbi->s_showassoc =='y' ||
148                                 (!(de->flags[-sbi->s_high_sierra] & 4)))) {
149                         match = (isofs_cmp(dentry, dpnt, dlen) == 0);
150                 }
151                 if (match) {
152                         isofs_normalize_block_and_offset(de,
153                                                          &block_saved,
154                                                          &offset_saved);
155                         *block_rv = block_saved;
156                         *offset_rv = offset_saved;
157                         brelse(bh);
158                         return 1;
159                 }
160         }
161         brelse(bh);
162         return 0;
163 }
164
165 struct dentry *isofs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
166 {
167         int found;
168         unsigned long uninitialized_var(block);
169         unsigned long uninitialized_var(offset);
170         struct inode *inode;
171         struct page *page;
172
173         dentry->d_op = dir->i_sb->s_root->d_op;
174
175         page = alloc_page(GFP_USER);
176         if (!page)
177                 return ERR_PTR(-ENOMEM);
178
179         lock_kernel();
180         found = isofs_find_entry(dir, dentry,
181                                 &block, &offset,
182                                 page_address(page),
183                                 1024 + page_address(page));
184         __free_page(page);
185
186         inode = NULL;
187         if (found) {
188                 inode = isofs_iget(dir->i_sb, block, offset);
189                 if (IS_ERR(inode)) {
190                         unlock_kernel();
191                         return ERR_CAST(inode);
192                 }
193         }
194         unlock_kernel();
195         return d_splice_alias(inode, dentry);
196 }