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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Tejun Heo5a0e3ad2010-03-24 17:04:11 +09009#include <linux/gfp.h>
Al Viro94f2f7152005-04-25 18:32:12 -070010#include "isofs.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070011
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 */
17static int
Dave Jonesc3ed85a2007-07-15 23:40:03 -070018isofs_cmp(struct dentry *dentry, const char *compare, int dlen)
Linus Torvalds1da177e2005-04-16 15:20:36 -070019{
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;
Linus Torvaldsda53be12013-05-21 15:22:44 -070040 return dentry->d_op->d_compare(NULL, NULL, dentry->d_name.len, dentry->d_name.name, &qstr);
Linus Torvalds1da177e2005-04-16 15:20:36 -070041}
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 */
49static unsigned long
50isofs_find_entry(struct inode *dir, struct dentry *dentry,
Dave Jonesc3ed85a2007-07-15 23:40:03 -070051 unsigned long *block_rv, unsigned long *offset_rv,
52 char *tmpname, struct iso_directory_record *tmpde)
Linus Torvalds1da177e2005-04-16 15:20:36 -070053{
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;
Dave Jonesc3ed85a2007-07-15 23:40:03 -070057 struct buffer_head *bh = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 struct isofs_sb_info *sbi = ISOFS_SB(dir->i_sb);
59
60 if (!ISOFS_I(dir)->i_first_extent)
61 return 0;
Dave Jonesc3ed85a2007-07-15 23:40:03 -070062
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 f_pos = 0;
64 offset = 0;
65 block = 0;
66
67 while (f_pos < dir->i_size) {
Dave Jonesc3ed85a2007-07-15 23:40:03 -070068 struct iso_directory_record *de;
Linus Torvalds1da177e2005-04-16 15:20:36 -070069 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;
Jan Kara2deb1ac2008-04-30 00:52:33 -0700114 /* 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 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121
122 if (sbi->s_rock &&
123 ((i = get_rock_ridge_filename(de, tmpname, dir)))) {
Dave Jonesc3ed85a2007-07-15 23:40:03 -0700124 dlen = i; /* possibly -1 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 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 /*
Jeremy White9769f4e2005-06-21 17:16:53 -0700140 * Skip hidden or associated files unless hide or showassoc,
141 * respectively, is set
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 */
143 match = 0;
144 if (dlen > 0 &&
Jan Kara5404ac82009-06-17 16:26:27 -0700145 (!sbi->s_hide ||
Jeremy White9769f4e2005-06-21 17:16:53 -0700146 (!(de->flags[-sbi->s_high_sierra] & 1))) &&
Jan Kara5404ac82009-06-17 16:26:27 -0700147 (sbi->s_showassoc ||
Jeremy White9769f4e2005-06-21 17:16:53 -0700148 (!(de->flags[-sbi->s_high_sierra] & 4)))) {
149 match = (isofs_cmp(dentry, dpnt, dlen) == 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 }
151 if (match) {
152 isofs_normalize_block_and_offset(de,
153 &block_saved,
154 &offset_saved);
Dave Jonesc3ed85a2007-07-15 23:40:03 -0700155 *block_rv = block_saved;
156 *offset_rv = offset_saved;
Jeremy White9769f4e2005-06-21 17:16:53 -0700157 brelse(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158 return 1;
159 }
160 }
Jeremy White9769f4e2005-06-21 17:16:53 -0700161 brelse(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 return 0;
163}
164
Al Viro00cd8dd2012-06-10 17:13:09 -0400165struct dentry *isofs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166{
167 int found;
Borislav Petkovcd215232007-10-16 23:30:05 -0700168 unsigned long uninitialized_var(block);
169 unsigned long uninitialized_var(offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 struct inode *inode;
171 struct page *page;
172
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 page = alloc_page(GFP_USER);
174 if (!page)
175 return ERR_PTR(-ENOMEM);
176
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177 found = isofs_find_entry(dir, dentry,
Dave Jonesc3ed85a2007-07-15 23:40:03 -0700178 &block, &offset,
179 page_address(page),
180 1024 + page_address(page));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 __free_page(page);
182
Al Viroa9049372011-07-08 21:20:11 -0400183 inode = found ? isofs_iget(dir->i_sb, block, offset) : NULL;
184
Pekka Enberg2ff6b1c2006-01-14 13:21:09 -0800185 return d_splice_alias(inode, dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186}