xref: /openbmc/linux/fs/adfs/dir.c (revision b6dcefde)
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 <linux/smp_lock.h>
13 #include "adfs.h"
14 
15 /*
16  * For future.  This should probably be per-directory.
17  */
18 static DEFINE_RWLOCK(adfs_dir_lock);
19 
20 static int
21 adfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
22 {
23 	struct inode *inode = filp->f_path.dentry->d_inode;
24 	struct super_block *sb = inode->i_sb;
25 	struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
26 	struct object_info obj;
27 	struct adfs_dir dir;
28 	int ret = 0;
29 
30 	lock_kernel();
31 
32 	if (filp->f_pos >> 32)
33 		goto out;
34 
35 	ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
36 	if (ret)
37 		goto out;
38 
39 	switch ((unsigned long)filp->f_pos) {
40 	case 0:
41 		if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
42 			goto free_out;
43 		filp->f_pos += 1;
44 
45 	case 1:
46 		if (filldir(dirent, "..", 2, 1, dir.parent_id, DT_DIR) < 0)
47 			goto free_out;
48 		filp->f_pos += 1;
49 
50 	default:
51 		break;
52 	}
53 
54 	read_lock(&adfs_dir_lock);
55 
56 	ret = ops->setpos(&dir, filp->f_pos - 2);
57 	if (ret)
58 		goto unlock_out;
59 	while (ops->getnext(&dir, &obj) == 0) {
60 		if (filldir(dirent, obj.name, obj.name_len,
61 			    filp->f_pos, obj.file_id, DT_UNKNOWN) < 0)
62 			goto unlock_out;
63 		filp->f_pos += 1;
64 	}
65 
66 unlock_out:
67 	read_unlock(&adfs_dir_lock);
68 
69 free_out:
70 	ops->free(&dir);
71 
72 out:
73 	unlock_kernel();
74 	return ret;
75 }
76 
77 int
78 adfs_dir_update(struct super_block *sb, struct object_info *obj, int wait)
79 {
80 	int ret = -EINVAL;
81 #ifdef CONFIG_ADFS_FS_RW
82 	struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
83 	struct adfs_dir dir;
84 
85 	printk(KERN_INFO "adfs_dir_update: object %06X in dir %06X\n",
86 		 obj->file_id, obj->parent_id);
87 
88 	if (!ops->update) {
89 		ret = -EINVAL;
90 		goto out;
91 	}
92 
93 	ret = ops->read(sb, obj->parent_id, 0, &dir);
94 	if (ret)
95 		goto out;
96 
97 	write_lock(&adfs_dir_lock);
98 	ret = ops->update(&dir, obj);
99 	write_unlock(&adfs_dir_lock);
100 
101 	if (wait) {
102 		int err = ops->sync(&dir);
103 		if (!ret)
104 			ret = err;
105 	}
106 
107 	ops->free(&dir);
108 out:
109 #endif
110 	return ret;
111 }
112 
113 static int
114 adfs_match(struct qstr *name, struct object_info *obj)
115 {
116 	int i;
117 
118 	if (name->len != obj->name_len)
119 		return 0;
120 
121 	for (i = 0; i < name->len; i++) {
122 		char c1, c2;
123 
124 		c1 = name->name[i];
125 		c2 = obj->name[i];
126 
127 		if (c1 >= 'A' && c1 <= 'Z')
128 			c1 += 'a' - 'A';
129 		if (c2 >= 'A' && c2 <= 'Z')
130 			c2 += 'a' - 'A';
131 
132 		if (c1 != c2)
133 			return 0;
134 	}
135 	return 1;
136 }
137 
138 static int
139 adfs_dir_lookup_byname(struct inode *inode, struct qstr *name, struct object_info *obj)
140 {
141 	struct super_block *sb = inode->i_sb;
142 	struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
143 	struct adfs_dir dir;
144 	int ret;
145 
146 	ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
147 	if (ret)
148 		goto out;
149 
150 	if (ADFS_I(inode)->parent_id != dir.parent_id) {
151 		adfs_error(sb, "parent directory changed under me! (%lx but got %lx)\n",
152 			   ADFS_I(inode)->parent_id, dir.parent_id);
153 		ret = -EIO;
154 		goto free_out;
155 	}
156 
157 	obj->parent_id = inode->i_ino;
158 
159 	/*
160 	 * '.' is handled by reserved_lookup() in fs/namei.c
161 	 */
162 	if (name->len == 2 && name->name[0] == '.' && name->name[1] == '.') {
163 		/*
164 		 * Currently unable to fill in the rest of 'obj',
165 		 * but this is better than nothing.  We need to
166 		 * ascend one level to find it's parent.
167 		 */
168 		obj->name_len = 0;
169 		obj->file_id  = obj->parent_id;
170 		goto free_out;
171 	}
172 
173 	read_lock(&adfs_dir_lock);
174 
175 	ret = ops->setpos(&dir, 0);
176 	if (ret)
177 		goto unlock_out;
178 
179 	ret = -ENOENT;
180 	while (ops->getnext(&dir, obj) == 0) {
181 		if (adfs_match(name, obj)) {
182 			ret = 0;
183 			break;
184 		}
185 	}
186 
187 unlock_out:
188 	read_unlock(&adfs_dir_lock);
189 
190 free_out:
191 	ops->free(&dir);
192 out:
193 	return ret;
194 }
195 
196 const struct file_operations adfs_dir_operations = {
197 	.read		= generic_read_dir,
198 	.llseek		= generic_file_llseek,
199 	.readdir	= adfs_readdir,
200 	.fsync		= simple_fsync,
201 };
202 
203 static int
204 adfs_hash(struct dentry *parent, struct qstr *qstr)
205 {
206 	const unsigned int name_len = ADFS_SB(parent->d_sb)->s_namelen;
207 	const unsigned char *name;
208 	unsigned long hash;
209 	int i;
210 
211 	if (qstr->len < name_len)
212 		return 0;
213 
214 	/*
215 	 * Truncate the name in place, avoids
216 	 * having to define a compare function.
217 	 */
218 	qstr->len = i = name_len;
219 	name = qstr->name;
220 	hash = init_name_hash();
221 	while (i--) {
222 		char c;
223 
224 		c = *name++;
225 		if (c >= 'A' && c <= 'Z')
226 			c += 'a' - 'A';
227 
228 		hash = partial_name_hash(c, hash);
229 	}
230 	qstr->hash = end_name_hash(hash);
231 
232 	return 0;
233 }
234 
235 /*
236  * Compare two names, taking note of the name length
237  * requirements of the underlying filesystem.
238  */
239 static int
240 adfs_compare(struct dentry *parent, struct qstr *entry, struct qstr *name)
241 {
242 	int i;
243 
244 	if (entry->len != name->len)
245 		return 1;
246 
247 	for (i = 0; i < name->len; i++) {
248 		char a, b;
249 
250 		a = entry->name[i];
251 		b = name->name[i];
252 
253 		if (a >= 'A' && a <= 'Z')
254 			a += 'a' - 'A';
255 		if (b >= 'A' && b <= 'Z')
256 			b += 'a' - 'A';
257 
258 		if (a != b)
259 			return 1;
260 	}
261 	return 0;
262 }
263 
264 const struct dentry_operations adfs_dentry_operations = {
265 	.d_hash		= adfs_hash,
266 	.d_compare	= adfs_compare,
267 };
268 
269 static struct dentry *
270 adfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
271 {
272 	struct inode *inode = NULL;
273 	struct object_info obj;
274 	int error;
275 
276 	dentry->d_op = &adfs_dentry_operations;
277 	lock_kernel();
278 	error = adfs_dir_lookup_byname(dir, &dentry->d_name, &obj);
279 	if (error == 0) {
280 		error = -EACCES;
281 		/*
282 		 * This only returns NULL if get_empty_inode
283 		 * fails.
284 		 */
285 		inode = adfs_iget(dir->i_sb, &obj);
286 		if (inode)
287 			error = 0;
288 	}
289 	unlock_kernel();
290 	d_add(dentry, inode);
291 	return ERR_PTR(error);
292 }
293 
294 /*
295  * directories can handle most operations...
296  */
297 const struct inode_operations adfs_dir_inode_operations = {
298 	.lookup		= adfs_lookup,
299 	.setattr	= adfs_notify_change,
300 };
301