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/sched.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/malloc.h>
16 #include <linux/errno.h>
17 #include <linux/config.h> /* Joliet? */
18
19 #include <asm/uaccess.h>
20
21 /*
22 * ok, we cannot use strncmp, as the name is not in our data space.
23 * Thus we'll have to use isofs_match. No big problem. Match also makes
24 * some sanity tests.
25 */
26 static int
27 isofs_cmp(struct dentry * dentry, const char * compare, int dlen)
28 {
29 struct qstr qstr;
30
31 if (!compare)
32 return 1;
33
34 /* check special "." and ".." files */
35 if (dlen == 1) {
36 /* "." */
37 if (compare[0] == 0) {
38 if (!dentry->d_name.len)
39 return 0;
40 compare = ".";
41 } else if (compare[0] == 1) {
42 compare = "..";
43 dlen = 2;
44 }
45 }
46
47 qstr.name = compare;
48 qstr.len = dlen;
49 return dentry->d_op->d_compare(dentry, &dentry->d_name, &qstr);
50 }
51
52 /*
53 * isofs_find_entry()
54 *
55 * finds an entry in the specified directory with the wanted name. It
56 * returns the inode number of the found entry, or 0 on error.
57 */
58 static unsigned long
59 isofs_find_entry(struct inode *dir, struct dentry *dentry,
60 char * tmpname, struct iso_directory_record * tmpde)
61 {
62 unsigned long inode_number;
63 unsigned long bufsize = ISOFS_BUFFER_SIZE(dir);
64 unsigned char bufbits = ISOFS_BUFFER_BITS(dir);
65 unsigned int block, f_pos, offset;
66 struct buffer_head * bh = NULL;
67
68 if (!dir->u.isofs_i.i_first_extent)
69 return 0;
70
71 f_pos = 0;
72 offset = 0;
73 block = 0;
74
75 while (f_pos < dir->i_size) {
76 struct iso_directory_record * de;
77 int de_len, match, i, dlen;
78 char *dpnt;
79
80 if (!bh) {
81 bh = isofs_bread(dir, bufsize, block);
82 if (!bh)
83 return 0;
84 }
85
86 de = (struct iso_directory_record *) (bh->b_data + offset);
87 inode_number = (bh->b_blocknr << bufbits) + offset;
88
89 de_len = *(unsigned char *) de;
90 if (!de_len) {
91 brelse(bh);
92 bh = NULL;
93 f_pos = (f_pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
94 block = f_pos >> bufbits;
95 offset = 0;
96 continue;
97 }
98
99 offset += de_len;
100 f_pos += de_len;
101
102 /* Make sure we have a full directory entry */
103 if (offset >= bufsize) {
104 int slop = bufsize - offset + de_len;
105 memcpy(tmpde, de, slop);
106 offset &= bufsize - 1;
107 block++;
108 brelse(bh);
109 bh = NULL;
110 if (offset) {
111 bh = isofs_bread(dir, bufsize, block);
112 if (!bh)
113 return 0;
114 memcpy((void *) tmpde + slop, bh->b_data, offset);
115 }
116 de = tmpde;
117 }
118
119 dlen = de->name_len[0];
120 dpnt = de->name;
121
122 if (dir->i_sb->u.isofs_sb.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 (dir->i_sb->u.isofs_sb.s_joliet_level) {
128 dlen = get_joliet_filename(de, tmpname, dir);
129 dpnt = tmpname;
130 #endif
131 } else if (dir->i_sb->u.isofs_sb.s_mapping == 'a') {
132 dlen = get_acorn_filename(de, tmpname, dir);
133 dpnt = tmpname;
134 } else if (dir->i_sb->u.isofs_sb.s_mapping == 'n') {
135 dlen = isofs_name_translate(de, tmpname, dir);
136 dpnt = tmpname;
137 }
138
139 /*
140 * Skip hidden or associated files unless unhide is set
141 */
142 match = 0;
143 if (dlen > 0 &&
144 (!(de->flags[-dir->i_sb->u.isofs_sb.s_high_sierra] & 5)
145 || dir->i_sb->u.isofs_sb.s_unhide == 'y'))
146 {
147 match = (isofs_cmp(dentry,dpnt,dlen) == 0);
148 }
149 if (match) {
150 if (bh) brelse(bh);
151 return inode_number;
152 }
153 }
154 if (bh) brelse(bh);
155 return 0;
156 }
157
158 struct dentry *isofs_lookup(struct inode * dir, struct dentry * dentry)
159 {
160 unsigned long ino;
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 ino = isofs_find_entry(dir, dentry, page_address(page),
171 1024 + page_address(page));
172 __free_page(page);
173
174 inode = NULL;
175 if (ino) {
176 inode = iget(dir->i_sb, ino);
177 if (!inode)
178 return ERR_PTR(-EACCES);
179 }
180 d_add(dentry, inode);
181 return NULL;
182 }
183
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