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/time.h>
10 #include <linux/iso_fs.h>
11 #include <linux/kernel.h>
12 #include <linux/string.h>
13 #include <linux/stat.h>
14 #include <linux/fcntl.h>
15 #include <linux/mm.h>
16 #include <linux/errno.h>
17 #include <linux/config.h> /* Joliet? */
18 #include <linux/smp_lock.h>
19 #include <linux/buffer_head.h>
20 #include <linux/dcache.h>
21
22 #include <asm/uaccess.h>
23
24 /*
25 * ok, we cannot use strncmp, as the name is not in our data space.
26 * Thus we'll have to use isofs_match. No big problem. Match also makes
27 * some sanity tests.
28 */
29 static int
30 isofs_cmp(struct dentry * dentry, const char * compare, int dlen)
31 {
32 struct qstr qstr;
33
34 if (!compare)
35 return 1;
36
37 /* check special "." and ".." files */
38 if (dlen == 1) {
39 /* "." */
40 if (compare[0] == 0) {
41 if (!dentry->d_name.len)
42 return 0;
43 compare = ".";
44 } else if (compare[0] == 1) {
45 compare = "..";
46 dlen = 2;
47 }
48 }
49
50 qstr.name = compare;
51 qstr.len = dlen;
52 return dentry->d_op->d_compare(dentry, &dentry->d_name, &qstr);
53 }
54
55 /*
56 * isofs_find_entry()
57 *
58 * finds an entry in the specified directory with the wanted name. It
59 * returns the inode number of the found entry, or 0 on error.
60 */
61 static unsigned long
62 isofs_find_entry(struct inode *dir, struct dentry *dentry,
63 unsigned long *block_rv, unsigned long* offset_rv,
64 char * tmpname, struct iso_directory_record * tmpde)
65 {
66 unsigned long bufsize = ISOFS_BUFFER_SIZE(dir);
67 unsigned char bufbits = ISOFS_BUFFER_BITS(dir);
68 unsigned long block, f_pos, offset, block_saved, offset_saved;
69 struct buffer_head * bh = NULL;
70 struct isofs_sb_info *sbi = ISOFS_SB(dir->i_sb);
71
72 if (!ISOFS_I(dir)->i_first_extent)
73 return 0;
74
75 f_pos = 0;
76 offset = 0;
77 block = 0;
78
79 while (f_pos < dir->i_size) {
80 struct iso_directory_record * de;
81 int de_len, match, i, dlen;
82 char *dpnt;
83
84 if (!bh) {
85 bh = isofs_bread(dir, block);
86 if (!bh)
87 return 0;
88 }
89
90 de = (struct iso_directory_record *) (bh->b_data + offset);
91
92 de_len = *(unsigned char *) de;
93 if (!de_len) {
94 brelse(bh);
95 bh = NULL;
96 f_pos = (f_pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
97 block = f_pos >> bufbits;
98 offset = 0;
99 continue;
100 }
101
102 block_saved = bh->b_blocknr;
103 offset_saved = offset;
104 offset += de_len;
105 f_pos += de_len;
106
107 /* Make sure we have a full directory entry */
108 if (offset >= bufsize) {
109 int slop = bufsize - offset + de_len;
110 memcpy(tmpde, de, slop);
111 offset &= bufsize - 1;
112 block++;
113 brelse(bh);
114 bh = NULL;
115 if (offset) {
116 bh = isofs_bread(dir, block);
117 if (!bh)
118 return 0;
119 memcpy((void *) tmpde + slop, bh->b_data, offset);
120 }
121 de = tmpde;
122 }
123
124 dlen = de->name_len[0];
125 dpnt = de->name;
126
127 if (sbi->s_rock &&
128 ((i = get_rock_ridge_filename(de, tmpname, dir)))) {
129 dlen = i; /* possibly -1 */
130 dpnt = tmpname;
131 #ifdef CONFIG_JOLIET
132 } else if (sbi->s_joliet_level) {
133 dlen = get_joliet_filename(de, tmpname, dir);
134 dpnt = tmpname;
135 #endif
136 } else if (sbi->s_mapping == 'a') {
137 dlen = get_acorn_filename(de, tmpname, dir);
138 dpnt = tmpname;
139 } else if (sbi->s_mapping == 'n') {
140 dlen = isofs_name_translate(de, tmpname, dir);
141 dpnt = tmpname;
142 }
143
144 /*
145 * Skip hidden or associated files unless unhide is set
146 */
147 match = 0;
148 if (dlen > 0 &&
149 (!(de->flags[-sbi->s_high_sierra] & 5)
150 || sbi->s_unhide == 'y'))
151 {
152 match = (isofs_cmp(dentry,dpnt,dlen) == 0);
153 }
154 if (match) {
155 isofs_normalize_block_and_offset(de,
156 &block_saved,
157 &offset_saved);
158 *block_rv = block_saved;
159 *offset_rv = offset_saved;
160 if (bh) brelse(bh);
161 return 1;
162 }
163 }
164 if (bh) brelse(bh);
165 return 0;
166 }
167
168 struct dentry *isofs_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
169 {
170 int found;
171 unsigned long block, offset;
172 struct inode *inode;
173 struct page *page;
174
175 dentry->d_op = dir->i_sb->s_root->d_op;
176
177 page = alloc_page(GFP_USER);
178 if (!page)
179 return ERR_PTR(-ENOMEM);
180
181 lock_kernel();
182 found = isofs_find_entry(dir, dentry,
183 &block, &offset,
184 page_address(page),
185 1024 + page_address(page));
186 __free_page(page);
187
188 inode = NULL;
189 if (found) {
190 inode = isofs_iget(dir->i_sb, block, offset);
191 if (!inode) {
192 unlock_kernel();
193 return ERR_PTR(-EACCES);
194 }
195 }
196 unlock_kernel();
197 if (inode)
198 return d_splice_alias(inode, dentry);
199 d_add(dentry, inode);
200 return NULL;
201 }
202
|
This page was automatically generated by the
LXR engine.
|