xref: /openbmc/linux/fs/adfs/dir.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
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/config.h>
13 #include <linux/errno.h>
14 #include <linux/fs.h>
15 #include <linux/adfs_fs.h>
16 #include <linux/time.h>
17 #include <linux/stat.h>
18 #include <linux/spinlock.h>
19 #include <linux/smp_lock.h>
20 #include <linux/buffer_head.h>		/* for file_fsync() */
21 
22 #include "adfs.h"
23 
24 /*
25  * For future.  This should probably be per-directory.
26  */
27 static DEFINE_RWLOCK(adfs_dir_lock);
28 
29 static int
30 adfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
31 {
32 	struct inode *inode = filp->f_dentry->d_inode;
33 	struct super_block *sb = inode->i_sb;
34 	struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
35 	struct object_info obj;
36 	struct adfs_dir dir;
37 	int ret = 0;
38 
39 	lock_kernel();
40 
41 	if (filp->f_pos >> 32)
42 		goto out;
43 
44 	ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
45 	if (ret)
46 		goto out;
47 
48 	switch ((unsigned long)filp->f_pos) {
49 	case 0:
50 		if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
51 			goto free_out;
52 		filp->f_pos += 1;
53 
54 	case 1:
55 		if (filldir(dirent, "..", 2, 1, dir.parent_id, DT_DIR) < 0)
56 			goto free_out;
57 		filp->f_pos += 1;
58 
59 	default:
60 		break;
61 	}
62 
63 	read_lock(&adfs_dir_lock);
64 
65 	ret = ops->setpos(&dir, filp->f_pos - 2);
66 	if (ret)
67 		goto unlock_out;
68 	while (ops->getnext(&dir, &obj) == 0) {
69 		if (filldir(dirent, obj.name, obj.name_len,
70 			    filp->f_pos, obj.file_id, DT_UNKNOWN) < 0)
71 			goto unlock_out;
72 		filp->f_pos += 1;
73 	}
74 
75 unlock_out:
76 	read_unlock(&adfs_dir_lock);
77 
78 free_out:
79 	ops->free(&dir);
80 
81 out:
82 	unlock_kernel();
83 	return ret;
84 }
85 
86 int
87 adfs_dir_update(struct super_block *sb, struct object_info *obj)
88 {
89 	int ret = -EINVAL;
90 #ifdef CONFIG_ADFS_FS_RW
91 	struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
92 	struct adfs_dir dir;
93 
94 	printk(KERN_INFO "adfs_dir_update: object %06X in dir %06X\n",
95 		 obj->file_id, obj->parent_id);
96 
97 	if (!ops->update) {
98 		ret = -EINVAL;
99 		goto out;
100 	}
101 
102 	ret = ops->read(sb, obj->parent_id, 0, &dir);
103 	if (ret)
104 		goto out;
105 
106 	write_lock(&adfs_dir_lock);
107 	ret = ops->update(&dir, obj);
108 	write_unlock(&adfs_dir_lock);
109 
110 	ops->free(&dir);
111 out:
112 #endif
113 	return ret;
114 }
115 
116 static int
117 adfs_match(struct qstr *name, struct object_info *obj)
118 {
119 	int i;
120 
121 	if (name->len != obj->name_len)
122 		return 0;
123 
124 	for (i = 0; i < name->len; i++) {
125 		char c1, c2;
126 
127 		c1 = name->name[i];
128 		c2 = obj->name[i];
129 
130 		if (c1 >= 'A' && c1 <= 'Z')
131 			c1 += 'a' - 'A';
132 		if (c2 >= 'A' && c2 <= 'Z')
133 			c2 += 'a' - 'A';
134 
135 		if (c1 != c2)
136 			return 0;
137 	}
138 	return 1;
139 }
140 
141 static int
142 adfs_dir_lookup_byname(struct inode *inode, struct qstr *name, struct object_info *obj)
143 {
144 	struct super_block *sb = inode->i_sb;
145 	struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
146 	struct adfs_dir dir;
147 	int ret;
148 
149 	ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
150 	if (ret)
151 		goto out;
152 
153 	if (ADFS_I(inode)->parent_id != dir.parent_id) {
154 		adfs_error(sb, "parent directory changed under me! (%lx but got %lx)\n",
155 			   ADFS_I(inode)->parent_id, dir.parent_id);
156 		ret = -EIO;
157 		goto free_out;
158 	}
159 
160 	obj->parent_id = inode->i_ino;
161 
162 	/*
163 	 * '.' is handled by reserved_lookup() in fs/namei.c
164 	 */
165 	if (name->len == 2 && name->name[0] == '.' && name->name[1] == '.') {
166 		/*
167 		 * Currently unable to fill in the rest of 'obj',
168 		 * but this is better than nothing.  We need to
169 		 * ascend one level to find it's parent.
170 		 */
171 		obj->name_len = 0;
172 		obj->file_id  = obj->parent_id;
173 		goto free_out;
174 	}
175 
176 	read_lock(&adfs_dir_lock);
177 
178 	ret = ops->setpos(&dir, 0);
179 	if (ret)
180 		goto unlock_out;
181 
182 	ret = -ENOENT;
183 	while (ops->getnext(&dir, obj) == 0) {
184 		if (adfs_match(name, obj)) {
185 			ret = 0;
186 			break;
187 		}
188 	}
189 
190 unlock_out:
191 	read_unlock(&adfs_dir_lock);
192 
193 free_out:
194 	ops->free(&dir);
195 out:
196 	return ret;
197 }
198 
199 struct file_operations adfs_dir_operations = {
200 	.read		= generic_read_dir,
201 	.readdir	= adfs_readdir,
202 	.fsync		= file_fsync,
203 };
204 
205 static int
206 adfs_hash(struct dentry *parent, struct qstr *qstr)
207 {
208 	const unsigned int name_len = ADFS_SB(parent->d_sb)->s_namelen;
209 	const unsigned char *name;
210 	unsigned long hash;
211 	int i;
212 
213 	if (qstr->len < name_len)
214 		return 0;
215 
216 	/*
217 	 * Truncate the name in place, avoids
218 	 * having to define a compare function.
219 	 */
220 	qstr->len = i = name_len;
221 	name = qstr->name;
222 	hash = init_name_hash();
223 	while (i--) {
224 		char c;
225 
226 		c = *name++;
227 		if (c >= 'A' && c <= 'Z')
228 			c += 'a' - 'A';
229 
230 		hash = partial_name_hash(c, hash);
231 	}
232 	qstr->hash = end_name_hash(hash);
233 
234 	return 0;
235 }
236 
237 /*
238  * Compare two names, taking note of the name length
239  * requirements of the underlying filesystem.
240  */
241 static int
242 adfs_compare(struct dentry *parent, struct qstr *entry, struct qstr *name)
243 {
244 	int i;
245 
246 	if (entry->len != name->len)
247 		return 1;
248 
249 	for (i = 0; i < name->len; i++) {
250 		char a, b;
251 
252 		a = entry->name[i];
253 		b = name->name[i];
254 
255 		if (a >= 'A' && a <= 'Z')
256 			a += 'a' - 'A';
257 		if (b >= 'A' && b <= 'Z')
258 			b += 'a' - 'A';
259 
260 		if (a != b)
261 			return 1;
262 	}
263 	return 0;
264 }
265 
266 struct dentry_operations adfs_dentry_operations = {
267 	.d_hash		= adfs_hash,
268 	.d_compare	= adfs_compare,
269 };
270 
271 static struct dentry *
272 adfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
273 {
274 	struct inode *inode = NULL;
275 	struct object_info obj;
276 	int error;
277 
278 	dentry->d_op = &adfs_dentry_operations;
279 	lock_kernel();
280 	error = adfs_dir_lookup_byname(dir, &dentry->d_name, &obj);
281 	if (error == 0) {
282 		error = -EACCES;
283 		/*
284 		 * This only returns NULL if get_empty_inode
285 		 * fails.
286 		 */
287 		inode = adfs_iget(dir->i_sb, &obj);
288 		if (inode)
289 			error = 0;
290 	}
291 	unlock_kernel();
292 	d_add(dentry, inode);
293 	return ERR_PTR(error);
294 }
295 
296 /*
297  * directories can handle most operations...
298  */
299 struct inode_operations adfs_dir_inode_operations = {
300 	.lookup		= adfs_lookup,
301 	.setattr	= adfs_notify_change,
302 };
303