1 /*
2 * linux/fs/adfs/dir.c
3 *
4 * Copyright (C) 1999-2000 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Common directory handling for ADFS
11 */
12 #include "adfs.h"
13
14 /*
15 * For future. This should probably be per-directory.
16 */
17 static DEFINE_RWLOCK(adfs_dir_lock);
18
19 static int
adfs_readdir(struct file * file,struct dir_context * ctx)20 adfs_readdir(struct file *file, struct dir_context *ctx)
21 {
22 struct inode *inode = file_inode(file);
23 struct super_block *sb = inode->i_sb;
24 struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
25 struct object_info obj;
26 struct adfs_dir dir;
27 int ret = 0;
28
29 if (ctx->pos >> 32)
30 return 0;
31
32 ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
33 if (ret)
34 return ret;
35
36 if (ctx->pos == 0) {
37 if (!dir_emit_dot(file, ctx))
38 goto free_out;
39 ctx->pos = 1;
40 }
41 if (ctx->pos == 1) {
42 if (!dir_emit(ctx, "..", 2, dir.parent_id, DT_DIR))
43 goto free_out;
44 ctx->pos = 2;
45 }
46
47 read_lock(&adfs_dir_lock);
48
49 ret = ops->setpos(&dir, ctx->pos - 2);
50 if (ret)
51 goto unlock_out;
52 while (ops->getnext(&dir, &obj) == 0) {
53 if (!dir_emit(ctx, obj.name, obj.name_len,
54 obj.file_id, DT_UNKNOWN))
55 break;
56 ctx->pos++;
57 }
58
59 unlock_out:
60 read_unlock(&adfs_dir_lock);
61
62 free_out:
63 ops->free(&dir);
64 return ret;
65 }
66
67 int
adfs_dir_update(struct super_block * sb,struct object_info * obj,int wait)68 adfs_dir_update(struct super_block *sb, struct object_info *obj, int wait)
69 {
70 int ret = -EINVAL;
71 #ifdef CONFIG_ADFS_FS_RW
72 struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
73 struct adfs_dir dir;
74
75 printk(KERN_INFO "adfs_dir_update: object %06X in dir %06X\n",
76 obj->file_id, obj->parent_id);
77
78 if (!ops->update) {
79 ret = -EINVAL;
80 goto out;
81 }
82
83 ret = ops->read(sb, obj->parent_id, 0, &dir);
84 if (ret)
85 goto out;
86
87 write_lock(&adfs_dir_lock);
88 ret = ops->update(&dir, obj);
89 write_unlock(&adfs_dir_lock);
90
91 if (wait) {
92 int err = ops->sync(&dir);
93 if (!ret)
94 ret = err;
95 }
96
97 ops->free(&dir);
98 out:
99 #endif
100 return ret;
101 }
102
103 static int
adfs_match(struct qstr * name,struct object_info * obj)104 adfs_match(struct qstr *name, struct object_info *obj)
105 {
106 int i;
107
108 if (name->len != obj->name_len)
109 return 0;
110
111 for (i = 0; i < name->len; i++) {
112 char c1, c2;
113
114 c1 = name->name[i];
115 c2 = obj->name[i];
116
117 if (c1 >= 'A' && c1 <= 'Z')
118 c1 += 'a' - 'A';
119 if (c2 >= 'A' && c2 <= 'Z')
120 c2 += 'a' - 'A';
121
122 if (c1 != c2)
123 return 0;
124 }
125 return 1;
126 }
127
128 static int
adfs_dir_lookup_byname(struct inode * inode,struct qstr * name,struct object_info * obj)129 adfs_dir_lookup_byname(struct inode *inode, struct qstr *name, struct object_info *obj)
130 {
131 struct super_block *sb = inode->i_sb;
132 struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
133 struct adfs_dir dir;
134 int ret;
135
136 ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
137 if (ret)
138 goto out;
139
140 if (ADFS_I(inode)->parent_id != dir.parent_id) {
141 adfs_error(sb, "parent directory changed under me! (%lx but got %x)\n",
142 ADFS_I(inode)->parent_id, dir.parent_id);
143 ret = -EIO;
144 goto free_out;
145 }
146
147 obj->parent_id = inode->i_ino;
148
149 /*
150 * '.' is handled by reserved_lookup() in fs/namei.c
151 */
152 if (name->len == 2 && name->name[0] == '.' && name->name[1] == '.') {
153 /*
154 * Currently unable to fill in the rest of 'obj',
155 * but this is better than nothing. We need to
156 * ascend one level to find it's parent.
157 */
158 obj->name_len = 0;
159 obj->file_id = obj->parent_id;
160 goto free_out;
161 }
162
163 read_lock(&adfs_dir_lock);
164
165 ret = ops->setpos(&dir, 0);
166 if (ret)
167 goto unlock_out;
168
169 ret = -ENOENT;
170 while (ops->getnext(&dir, obj) == 0) {
171 if (adfs_match(name, obj)) {
172 ret = 0;
173 break;
174 }
175 }
176
177 unlock_out:
178 read_unlock(&adfs_dir_lock);
179
180 free_out:
181 ops->free(&dir);
182 out:
183 return ret;
184 }
185
186 const struct file_operations adfs_dir_operations = {
187 .read = generic_read_dir,
188 .llseek = generic_file_llseek,
189 .iterate = adfs_readdir,
190 .fsync = generic_file_fsync,
191 };
192
193 static int
adfs_hash(const struct dentry * parent,struct qstr * qstr)194 adfs_hash(const struct dentry *parent, struct qstr *qstr)
195 {
196 const unsigned int name_len = ADFS_SB(parent->d_sb)->s_namelen;
197 const unsigned char *name;
198 unsigned long hash;
199 int i;
200
201 if (qstr->len < name_len)
202 return 0;
203
204 /*
205 * Truncate the name in place, avoids
206 * having to define a compare function.
207 */
208 qstr->len = i = name_len;
209 name = qstr->name;
210 hash = init_name_hash();
211 while (i--) {
212 char c;
213
214 c = *name++;
215 if (c >= 'A' && c <= 'Z')
216 c += 'a' - 'A';
217
218 hash = partial_name_hash(c, hash);
219 }
220 qstr->hash = end_name_hash(hash);
221
222 return 0;
223 }
224
225 /*
226 * Compare two names, taking note of the name length
227 * requirements of the underlying filesystem.
228 */
229 static int
adfs_compare(const struct dentry * parent,const struct dentry * dentry,unsigned int len,const char * str,const struct qstr * name)230 adfs_compare(const struct dentry *parent, const struct dentry *dentry,
231 unsigned int len, const char *str, const struct qstr *name)
232 {
233 int i;
234
235 if (len != name->len)
236 return 1;
237
238 for (i = 0; i < name->len; i++) {
239 char a, b;
240
241 a = str[i];
242 b = name->name[i];
243
244 if (a >= 'A' && a <= 'Z')
245 a += 'a' - 'A';
246 if (b >= 'A' && b <= 'Z')
247 b += 'a' - 'A';
248
249 if (a != b)
250 return 1;
251 }
252 return 0;
253 }
254
255 const struct dentry_operations adfs_dentry_operations = {
256 .d_hash = adfs_hash,
257 .d_compare = adfs_compare,
258 };
259
260 static struct dentry *
adfs_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)261 adfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
262 {
263 struct inode *inode = NULL;
264 struct object_info obj;
265 int error;
266
267 error = adfs_dir_lookup_byname(dir, &dentry->d_name, &obj);
268 if (error == 0) {
269 error = -EACCES;
270 /*
271 * This only returns NULL if get_empty_inode
272 * fails.
273 */
274 inode = adfs_iget(dir->i_sb, &obj);
275 if (inode)
276 error = 0;
277 }
278 d_add(dentry, inode);
279 return ERR_PTR(error);
280 }
281
282 /*
283 * directories can handle most operations...
284 */
285 const struct inode_operations adfs_dir_inode_operations = {
286 .lookup = adfs_lookup,
287 .setattr = adfs_notify_change,
288 };
289