xref: /openbmc/linux/fs/affs/namei.c (revision 1c2dd16a) 
1 /*
2  *  linux/fs/affs/namei.c
3  *
4  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
5  *
6  *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
7  *
8  *  (C) 1991  Linus Torvalds - minix filesystem
9  */
10 
11 #include "affs.h"
12 #include <linux/exportfs.h>
13 
14 typedef int (*toupper_t)(int);
15 
16 /* Simple toupper() for DOS\1 */
17 
18 static int
19 affs_toupper(int ch)
20 {
21 	return ch >= 'a' && ch <= 'z' ? ch -= ('a' - 'A') : ch;
22 }
23 
24 /* International toupper() for DOS\3 ("international") */
25 
26 static int
27 affs_intl_toupper(int ch)
28 {
29 	return (ch >= 'a' && ch <= 'z') || (ch >= 0xE0
30 		&& ch <= 0xFE && ch != 0xF7) ?
31 		ch - ('a' - 'A') : ch;
32 }
33 
34 static inline toupper_t
35 affs_get_toupper(struct super_block *sb)
36 {
37 	return affs_test_opt(AFFS_SB(sb)->s_flags, SF_INTL) ?
38 	       affs_intl_toupper : affs_toupper;
39 }
40 
41 /*
42  * Note: the dentry argument is the parent dentry.
43  */
44 static inline int
45 __affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr, toupper_t toupper, bool notruncate)
46 {
47 	const u8 *name = qstr->name;
48 	unsigned long hash;
49 	int retval;
50 	u32 len;
51 
52 	retval = affs_check_name(qstr->name, qstr->len, notruncate);
53 	if (retval)
54 		return retval;
55 
56 	hash = init_name_hash(dentry);
57 	len = min(qstr->len, AFFSNAMEMAX);
58 	for (; len > 0; name++, len--)
59 		hash = partial_name_hash(toupper(*name), hash);
60 	qstr->hash = end_name_hash(hash);
61 
62 	return 0;
63 }
64 
65 static int
66 affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
67 {
68 	return __affs_hash_dentry(dentry, qstr, affs_toupper,
69 				  affs_nofilenametruncate(dentry));
70 
71 }
72 
73 static int
74 affs_intl_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
75 {
76 	return __affs_hash_dentry(dentry, qstr, affs_intl_toupper,
77 				  affs_nofilenametruncate(dentry));
78 
79 }
80 
81 static inline int __affs_compare_dentry(unsigned int len,
82 		const char *str, const struct qstr *name, toupper_t toupper,
83 		bool notruncate)
84 {
85 	const u8 *aname = str;
86 	const u8 *bname = name->name;
87 
88 	/*
89 	 * 'str' is the name of an already existing dentry, so the name
90 	 * must be valid. 'name' must be validated first.
91 	 */
92 
93 	if (affs_check_name(name->name, name->len, notruncate))
94 		return 1;
95 
96 	/*
97 	 * If the names are longer than the allowed 30 chars,
98 	 * the excess is ignored, so their length may differ.
99 	 */
100 	if (len >= AFFSNAMEMAX) {
101 		if (name->len < AFFSNAMEMAX)
102 			return 1;
103 		len = AFFSNAMEMAX;
104 	} else if (len != name->len)
105 		return 1;
106 
107 	for (; len > 0; len--)
108 		if (toupper(*aname++) != toupper(*bname++))
109 			return 1;
110 
111 	return 0;
112 }
113 
114 static int
115 affs_compare_dentry(const struct dentry *dentry,
116 		unsigned int len, const char *str, const struct qstr *name)
117 {
118 
119 	return __affs_compare_dentry(len, str, name, affs_toupper,
120 				     affs_nofilenametruncate(dentry));
121 }
122 
123 static int
124 affs_intl_compare_dentry(const struct dentry *dentry,
125 		unsigned int len, const char *str, const struct qstr *name)
126 {
127 	return __affs_compare_dentry(len, str, name, affs_intl_toupper,
128 				     affs_nofilenametruncate(dentry));
129 
130 }
131 
132 /*
133  * NOTE! unlike strncmp, affs_match returns 1 for success, 0 for failure.
134  */
135 
136 static inline int
137 affs_match(struct dentry *dentry, const u8 *name2, toupper_t toupper)
138 {
139 	const u8 *name = dentry->d_name.name;
140 	int len = dentry->d_name.len;
141 
142 	if (len >= AFFSNAMEMAX) {
143 		if (*name2 < AFFSNAMEMAX)
144 			return 0;
145 		len = AFFSNAMEMAX;
146 	} else if (len != *name2)
147 		return 0;
148 
149 	for (name2++; len > 0; len--)
150 		if (toupper(*name++) != toupper(*name2++))
151 			return 0;
152 	return 1;
153 }
154 
155 int
156 affs_hash_name(struct super_block *sb, const u8 *name, unsigned int len)
157 {
158 	toupper_t toupper = affs_get_toupper(sb);
159 	u32 hash;
160 
161 	hash = len = min(len, AFFSNAMEMAX);
162 	for (; len > 0; len--)
163 		hash = (hash * 13 + toupper(*name++)) & 0x7ff;
164 
165 	return hash % AFFS_SB(sb)->s_hashsize;
166 }
167 
168 static struct buffer_head *
169 affs_find_entry(struct inode *dir, struct dentry *dentry)
170 {
171 	struct super_block *sb = dir->i_sb;
172 	struct buffer_head *bh;
173 	toupper_t toupper = affs_get_toupper(sb);
174 	u32 key;
175 
176 	pr_debug("%s(\"%pd\")\n", __func__, dentry);
177 
178 	bh = affs_bread(sb, dir->i_ino);
179 	if (!bh)
180 		return ERR_PTR(-EIO);
181 
182 	key = be32_to_cpu(AFFS_HEAD(bh)->table[affs_hash_name(sb, dentry->d_name.name, dentry->d_name.len)]);
183 
184 	for (;;) {
185 		affs_brelse(bh);
186 		if (key == 0)
187 			return NULL;
188 		bh = affs_bread(sb, key);
189 		if (!bh)
190 			return ERR_PTR(-EIO);
191 		if (affs_match(dentry, AFFS_TAIL(sb, bh)->name, toupper))
192 			return bh;
193 		key = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
194 	}
195 }
196 
197 struct dentry *
198 affs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
199 {
200 	struct super_block *sb = dir->i_sb;
201 	struct buffer_head *bh;
202 	struct inode *inode = NULL;
203 
204 	pr_debug("%s(\"%pd\")\n", __func__, dentry);
205 
206 	affs_lock_dir(dir);
207 	bh = affs_find_entry(dir, dentry);
208 	affs_unlock_dir(dir);
209 	if (IS_ERR(bh))
210 		return ERR_CAST(bh);
211 	if (bh) {
212 		u32 ino = bh->b_blocknr;
213 
214 		/* store the real header ino in d_fsdata for faster lookups */
215 		dentry->d_fsdata = (void *)(long)ino;
216 		switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
217 		//link to dirs disabled
218 		//case ST_LINKDIR:
219 		case ST_LINKFILE:
220 			ino = be32_to_cpu(AFFS_TAIL(sb, bh)->original);
221 		}
222 		affs_brelse(bh);
223 		inode = affs_iget(sb, ino);
224 		if (IS_ERR(inode))
225 			return ERR_CAST(inode);
226 	}
227 	d_add(dentry, inode);
228 	return NULL;
229 }
230 
231 int
232 affs_unlink(struct inode *dir, struct dentry *dentry)
233 {
234 	pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
235 		 d_inode(dentry)->i_ino, dentry);
236 
237 	return affs_remove_header(dentry);
238 }
239 
240 int
241 affs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
242 {
243 	struct super_block *sb = dir->i_sb;
244 	struct inode	*inode;
245 	int		 error;
246 
247 	pr_debug("%s(%lu,\"%pd\",0%ho)\n",
248 		 __func__, dir->i_ino, dentry, mode);
249 
250 	inode = affs_new_inode(dir);
251 	if (!inode)
252 		return -ENOSPC;
253 
254 	inode->i_mode = mode;
255 	affs_mode_to_prot(inode);
256 	mark_inode_dirty(inode);
257 
258 	inode->i_op = &affs_file_inode_operations;
259 	inode->i_fop = &affs_file_operations;
260 	inode->i_mapping->a_ops = affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS) ?
261 				  &affs_aops_ofs : &affs_aops;
262 	error = affs_add_entry(dir, inode, dentry, ST_FILE);
263 	if (error) {
264 		clear_nlink(inode);
265 		iput(inode);
266 		return error;
267 	}
268 	return 0;
269 }
270 
271 int
272 affs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
273 {
274 	struct inode		*inode;
275 	int			 error;
276 
277 	pr_debug("%s(%lu,\"%pd\",0%ho)\n",
278 		 __func__, dir->i_ino, dentry, mode);
279 
280 	inode = affs_new_inode(dir);
281 	if (!inode)
282 		return -ENOSPC;
283 
284 	inode->i_mode = S_IFDIR | mode;
285 	affs_mode_to_prot(inode);
286 
287 	inode->i_op = &affs_dir_inode_operations;
288 	inode->i_fop = &affs_dir_operations;
289 
290 	error = affs_add_entry(dir, inode, dentry, ST_USERDIR);
291 	if (error) {
292 		clear_nlink(inode);
293 		mark_inode_dirty(inode);
294 		iput(inode);
295 		return error;
296 	}
297 	return 0;
298 }
299 
300 int
301 affs_rmdir(struct inode *dir, struct dentry *dentry)
302 {
303 	pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
304 		 d_inode(dentry)->i_ino, dentry);
305 
306 	return affs_remove_header(dentry);
307 }
308 
309 int
310 affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
311 {
312 	struct super_block	*sb = dir->i_sb;
313 	struct buffer_head	*bh;
314 	struct inode		*inode;
315 	char			*p;
316 	int			 i, maxlen, error;
317 	char			 c, lc;
318 
319 	pr_debug("%s(%lu,\"%pd\" -> \"%s\")\n",
320 		 __func__, dir->i_ino, dentry, symname);
321 
322 	maxlen = AFFS_SB(sb)->s_hashsize * sizeof(u32) - 1;
323 	inode  = affs_new_inode(dir);
324 	if (!inode)
325 		return -ENOSPC;
326 
327 	inode->i_op = &affs_symlink_inode_operations;
328 	inode_nohighmem(inode);
329 	inode->i_data.a_ops = &affs_symlink_aops;
330 	inode->i_mode = S_IFLNK | 0777;
331 	affs_mode_to_prot(inode);
332 
333 	error = -EIO;
334 	bh = affs_bread(sb, inode->i_ino);
335 	if (!bh)
336 		goto err;
337 	i  = 0;
338 	p  = (char *)AFFS_HEAD(bh)->table;
339 	lc = '/';
340 	if (*symname == '/') {
341 		struct affs_sb_info *sbi = AFFS_SB(sb);
342 		while (*symname == '/')
343 			symname++;
344 		spin_lock(&sbi->symlink_lock);
345 		while (sbi->s_volume[i])	/* Cannot overflow */
346 			*p++ = sbi->s_volume[i++];
347 		spin_unlock(&sbi->symlink_lock);
348 	}
349 	while (i < maxlen && (c = *symname++)) {
350 		if (c == '.' && lc == '/' && *symname == '.' && symname[1] == '/') {
351 			*p++ = '/';
352 			i++;
353 			symname += 2;
354 			lc = '/';
355 		} else if (c == '.' && lc == '/' && *symname == '/') {
356 			symname++;
357 			lc = '/';
358 		} else {
359 			*p++ = c;
360 			lc   = c;
361 			i++;
362 		}
363 		if (lc == '/')
364 			while (*symname == '/')
365 				symname++;
366 	}
367 	*p = 0;
368 	mark_buffer_dirty_inode(bh, inode);
369 	affs_brelse(bh);
370 	mark_inode_dirty(inode);
371 
372 	error = affs_add_entry(dir, inode, dentry, ST_SOFTLINK);
373 	if (error)
374 		goto err;
375 
376 	return 0;
377 
378 err:
379 	clear_nlink(inode);
380 	mark_inode_dirty(inode);
381 	iput(inode);
382 	return error;
383 }
384 
385 int
386 affs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
387 {
388 	struct inode *inode = d_inode(old_dentry);
389 
390 	pr_debug("%s(%lu, %lu, \"%pd\")\n", __func__, inode->i_ino, dir->i_ino,
391 		 dentry);
392 
393 	return affs_add_entry(dir, inode, dentry, ST_LINKFILE);
394 }
395 
396 int
397 affs_rename(struct inode *old_dir, struct dentry *old_dentry,
398 	    struct inode *new_dir, struct dentry *new_dentry,
399 	    unsigned int flags)
400 {
401 	struct super_block *sb = old_dir->i_sb;
402 	struct buffer_head *bh = NULL;
403 	int retval;
404 
405 	if (flags & ~RENAME_NOREPLACE)
406 		return -EINVAL;
407 
408 	pr_debug("%s(old=%lu,\"%pd\" to new=%lu,\"%pd\")\n", __func__,
409 		 old_dir->i_ino, old_dentry, new_dir->i_ino, new_dentry);
410 
411 	retval = affs_check_name(new_dentry->d_name.name,
412 				 new_dentry->d_name.len,
413 				 affs_nofilenametruncate(old_dentry));
414 
415 	if (retval)
416 		return retval;
417 
418 	/* Unlink destination if it already exists */
419 	if (d_really_is_positive(new_dentry)) {
420 		retval = affs_remove_header(new_dentry);
421 		if (retval)
422 			return retval;
423 	}
424 
425 	bh = affs_bread(sb, d_inode(old_dentry)->i_ino);
426 	if (!bh)
427 		return -EIO;
428 
429 	/* Remove header from its parent directory. */
430 	affs_lock_dir(old_dir);
431 	retval = affs_remove_hash(old_dir, bh);
432 	affs_unlock_dir(old_dir);
433 	if (retval)
434 		goto done;
435 
436 	/* And insert it into the new directory with the new name. */
437 	affs_copy_name(AFFS_TAIL(sb, bh)->name, new_dentry);
438 	affs_fix_checksum(sb, bh);
439 	affs_lock_dir(new_dir);
440 	retval = affs_insert_hash(new_dir, bh);
441 	affs_unlock_dir(new_dir);
442 	/* TODO: move it back to old_dir, if error? */
443 
444 done:
445 	mark_buffer_dirty_inode(bh, retval ? old_dir : new_dir);
446 	affs_brelse(bh);
447 	return retval;
448 }
449 
450 static struct dentry *affs_get_parent(struct dentry *child)
451 {
452 	struct inode *parent;
453 	struct buffer_head *bh;
454 
455 	bh = affs_bread(child->d_sb, d_inode(child)->i_ino);
456 	if (!bh)
457 		return ERR_PTR(-EIO);
458 
459 	parent = affs_iget(child->d_sb,
460 			   be32_to_cpu(AFFS_TAIL(child->d_sb, bh)->parent));
461 	brelse(bh);
462 	if (IS_ERR(parent))
463 		return ERR_CAST(parent);
464 
465 	return d_obtain_alias(parent);
466 }
467 
468 static struct inode *affs_nfs_get_inode(struct super_block *sb, u64 ino,
469 					u32 generation)
470 {
471 	struct inode *inode;
472 
473 	if (!affs_validblock(sb, ino))
474 		return ERR_PTR(-ESTALE);
475 
476 	inode = affs_iget(sb, ino);
477 	if (IS_ERR(inode))
478 		return ERR_CAST(inode);
479 
480 	if (generation && inode->i_generation != generation) {
481 		iput(inode);
482 		return ERR_PTR(-ESTALE);
483 	}
484 
485 	return inode;
486 }
487 
488 static struct dentry *affs_fh_to_dentry(struct super_block *sb, struct fid *fid,
489 					int fh_len, int fh_type)
490 {
491 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
492 				    affs_nfs_get_inode);
493 }
494 
495 static struct dentry *affs_fh_to_parent(struct super_block *sb, struct fid *fid,
496 					int fh_len, int fh_type)
497 {
498 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
499 				    affs_nfs_get_inode);
500 }
501 
502 const struct export_operations affs_export_ops = {
503 	.fh_to_dentry = affs_fh_to_dentry,
504 	.fh_to_parent = affs_fh_to_parent,
505 	.get_parent = affs_get_parent,
506 };
507 
508 const struct dentry_operations affs_dentry_operations = {
509 	.d_hash		= affs_hash_dentry,
510 	.d_compare	= affs_compare_dentry,
511 };
512 
513 const struct dentry_operations affs_intl_dentry_operations = {
514 	.d_hash		= affs_intl_hash_dentry,
515 	.d_compare	= affs_intl_compare_dentry,
516 };
517