ia64/linux-2.6.18-xen.hg

view fs/isofs/namei.c @ 524:7f8b544237bf

netfront: Allow netfront in domain 0.

This is useful if your physical network device is in a utility domain.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Tue Apr 15 15:18:58 2008 +0100 (2008-04-15)
parents 831230e53067
children
line source
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 */
9 #include <linux/config.h> /* Joliet? */
10 #include <linux/smp_lock.h>
11 #include "isofs.h"
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;
23 if (!compare)
24 return 1;
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 }
39 qstr.name = compare;
40 qstr.len = dlen;
41 return dentry->d_op->d_compare(dentry, &dentry->d_name, &qstr);
42 }
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);
61 if (!ISOFS_I(dir)->i_first_extent)
62 return 0;
64 f_pos = 0;
65 offset = 0;
66 block = 0;
68 while (f_pos < dir->i_size) {
69 struct iso_directory_record * de;
70 int de_len, match, i, dlen;
71 char *dpnt;
73 if (!bh) {
74 bh = isofs_bread(dir, block);
75 if (!bh)
76 return 0;
77 }
79 de = (struct iso_directory_record *) (bh->b_data + offset);
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 }
91 block_saved = bh->b_blocknr;
92 offset_saved = offset;
93 offset += de_len;
94 f_pos += de_len;
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 }
113 dlen = de->name_len[0];
114 dpnt = de->name;
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 }
133 /*
134 * Skip hidden or associated files unless hide or showassoc,
135 * respectively, is set
136 */
137 match = 0;
138 if (dlen > 0 &&
139 (sbi->s_hide =='n' ||
140 (!(de->flags[-sbi->s_high_sierra] & 1))) &&
141 (sbi->s_showassoc =='y' ||
142 (!(de->flags[-sbi->s_high_sierra] & 4)))) {
143 match = (isofs_cmp(dentry, dpnt, dlen) == 0);
144 }
145 if (match) {
146 isofs_normalize_block_and_offset(de,
147 &block_saved,
148 &offset_saved);
149 *block_rv = block_saved;
150 *offset_rv = offset_saved;
151 brelse(bh);
152 return 1;
153 }
154 }
155 brelse(bh);
156 return 0;
157 }
159 struct dentry *isofs_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
160 {
161 int found;
162 unsigned long block, offset;
163 struct inode *inode;
164 struct page *page;
166 dentry->d_op = dir->i_sb->s_root->d_op;
168 page = alloc_page(GFP_USER);
169 if (!page)
170 return ERR_PTR(-ENOMEM);
172 lock_kernel();
173 found = isofs_find_entry(dir, dentry,
174 &block, &offset,
175 page_address(page),
176 1024 + page_address(page));
177 __free_page(page);
179 inode = NULL;
180 if (found) {
181 inode = isofs_iget(dir->i_sb, block, offset);
182 if (!inode) {
183 unlock_kernel();
184 return ERR_PTR(-EACCES);
185 }
186 }
187 unlock_kernel();
188 return d_splice_alias(inode, dentry);
189 }