xref: /openbmc/linux/fs/affs/namei.c (revision e3b9f1e8) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/affs/namei.c
4  *
5  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
6  *
7  *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
8  *
9  *  (C) 1991  Linus Torvalds - minix filesystem
10  */
11 
12 #include "affs.h"
13 #include <linux/exportfs.h>
14 
15 typedef int (*toupper_t)(int);
16 
17 /* Simple toupper() for DOS\1 */
18 
19 static int
20 affs_toupper(int ch)
21 {
22 	return ch >= 'a' && ch <= 'z' ? ch -= ('a' - 'A') : ch;
23 }
24 
25 /* International toupper() for DOS\3 ("international") */
26 
27 static int
28 affs_intl_toupper(int ch)
29 {
30 	return (ch >= 'a' && ch <= 'z') || (ch >= 0xE0
31 		&& ch <= 0xFE && ch != 0xF7) ?
32 		ch - ('a' - 'A') : ch;
33 }
34 
35 static inline toupper_t
36 affs_get_toupper(struct super_block *sb)
37 {
38 	return affs_test_opt(AFFS_SB(sb)->s_flags, SF_INTL) ?
39 	       affs_intl_toupper : affs_toupper;
40 }
41 
42 /*
43  * Note: the dentry argument is the parent dentry.
44  */
45 static inline int
46 __affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr, toupper_t toupper, bool notruncate)
47 {
48 	const u8 *name = qstr->name;
49 	unsigned long hash;
50 	int retval;
51 	u32 len;
52 
53 	retval = affs_check_name(qstr->name, qstr->len, notruncate);
54 	if (retval)
55 		return retval;
56 
57 	hash = init_name_hash(dentry);
58 	len = min(qstr->len, AFFSNAMEMAX);
59 	for (; len > 0; name++, len--)
60 		hash = partial_name_hash(toupper(*name), hash);
61 	qstr->hash = end_name_hash(hash);
62 
63 	return 0;
64 }
65 
66 static int
67 affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
68 {
69 	return __affs_hash_dentry(dentry, qstr, affs_toupper,
70 				  affs_nofilenametruncate(dentry));
71 
72 }
73 
74 static int
75 affs_intl_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
76 {
77 	return __affs_hash_dentry(dentry, qstr, affs_intl_toupper,
78 				  affs_nofilenametruncate(dentry));
79 
80 }
81 
82 static inline int __affs_compare_dentry(unsigned int len,
83 		const char *str, const struct qstr *name, toupper_t toupper,
84 		bool notruncate)
85 {
86 	const u8 *aname = str;
87 	const u8 *bname = name->name;
88 
89 	/*
90 	 * 'str' is the name of an already existing dentry, so the name
91 	 * must be valid. 'name' must be validated first.
92 	 */
93 
94 	if (affs_check_name(name->name, name->len, notruncate))
95 		return 1;
96 
97 	/*
98 	 * If the names are longer than the allowed 30 chars,
99 	 * the excess is ignored, so their length may differ.
100 	 */
101 	if (len >= AFFSNAMEMAX) {
102 		if (name->len < AFFSNAMEMAX)
103 			return 1;
104 		len = AFFSNAMEMAX;
105 	} else if (len != name->len)
106 		return 1;
107 
108 	for (; len > 0; len--)
109 		if (toupper(*aname++) != toupper(*bname++))
110 			return 1;
111 
112 	return 0;
113 }
114 
115 static int
116 affs_compare_dentry(const struct dentry *dentry,
117 		unsigned int len, const char *str, const struct qstr *name)
118 {
119 
120 	return __affs_compare_dentry(len, str, name, affs_toupper,
121 				     affs_nofilenametruncate(dentry));
122 }
123 
124 static int
125 affs_intl_compare_dentry(const struct dentry *dentry,
126 		unsigned int len, const char *str, const struct qstr *name)
127 {
128 	return __affs_compare_dentry(len, str, name, affs_intl_toupper,
129 				     affs_nofilenametruncate(dentry));
130 
131 }
132 
133 /*
134  * NOTE! unlike strncmp, affs_match returns 1 for success, 0 for failure.
135  */
136 
137 static inline int
138 affs_match(struct dentry *dentry, const u8 *name2, toupper_t toupper)
139 {
140 	const u8 *name = dentry->d_name.name;
141 	int len = dentry->d_name.len;
142 
143 	if (len >= AFFSNAMEMAX) {
144 		if (*name2 < AFFSNAMEMAX)
145 			return 0;
146 		len = AFFSNAMEMAX;
147 	} else if (len != *name2)
148 		return 0;
149 
150 	for (name2++; len > 0; len--)
151 		if (toupper(*name++) != toupper(*name2++))
152 			return 0;
153 	return 1;
154 }
155 
156 int
157 affs_hash_name(struct super_block *sb, const u8 *name, unsigned int len)
158 {
159 	toupper_t toupper = affs_get_toupper(sb);
160 	u32 hash;
161 
162 	hash = len = min(len, AFFSNAMEMAX);
163 	for (; len > 0; len--)
164 		hash = (hash * 13 + toupper(*name++)) & 0x7ff;
165 
166 	return hash % AFFS_SB(sb)->s_hashsize;
167 }
168 
169 static struct buffer_head *
170 affs_find_entry(struct inode *dir, struct dentry *dentry)
171 {
172 	struct super_block *sb = dir->i_sb;
173 	struct buffer_head *bh;
174 	toupper_t toupper = affs_get_toupper(sb);
175 	u32 key;
176 
177 	pr_debug("%s(\"%pd\")\n", __func__, dentry);
178 
179 	bh = affs_bread(sb, dir->i_ino);
180 	if (!bh)
181 		return ERR_PTR(-EIO);
182 
183 	key = be32_to_cpu(AFFS_HEAD(bh)->table[affs_hash_name(sb, dentry->d_name.name, dentry->d_name.len)]);
184 
185 	for (;;) {
186 		affs_brelse(bh);
187 		if (key == 0)
188 			return NULL;
189 		bh = affs_bread(sb, key);
190 		if (!bh)
191 			return ERR_PTR(-EIO);
192 		if (affs_match(dentry, AFFS_TAIL(sb, bh)->name, toupper))
193 			return bh;
194 		key = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
195 	}
196 }
197 
198 struct dentry *
199 affs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
200 {
201 	struct super_block *sb = dir->i_sb;
202 	struct buffer_head *bh;
203 	struct inode *inode = NULL;
204 
205 	pr_debug("%s(\"%pd\")\n", __func__, dentry);
206 
207 	affs_lock_dir(dir);
208 	bh = affs_find_entry(dir, dentry);
209 	affs_unlock_dir(dir);
210 	if (IS_ERR(bh))
211 		return ERR_CAST(bh);
212 	if (bh) {
213 		u32 ino = bh->b_blocknr;
214 
215 		/* store the real header ino in d_fsdata for faster lookups */
216 		dentry->d_fsdata = (void *)(long)ino;
217 		switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
218 		//link to dirs disabled
219 		//case ST_LINKDIR:
220 		case ST_LINKFILE:
221 			ino = be32_to_cpu(AFFS_TAIL(sb, bh)->original);
222 		}
223 		affs_brelse(bh);
224 		inode = affs_iget(sb, ino);
225 		if (IS_ERR(inode))
226 			return ERR_CAST(inode);
227 	}
228 	d_add(dentry, inode);
229 	return NULL;
230 }
231 
232 int
233 affs_unlink(struct inode *dir, struct dentry *dentry)
234 {
235 	pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
236 		 d_inode(dentry)->i_ino, dentry);
237 
238 	return affs_remove_header(dentry);
239 }
240 
241 int
242 affs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
243 {
244 	struct super_block *sb = dir->i_sb;
245 	struct inode	*inode;
246 	int		 error;
247 
248 	pr_debug("%s(%lu,\"%pd\",0%ho)\n",
249 		 __func__, dir->i_ino, dentry, mode);
250 
251 	inode = affs_new_inode(dir);
252 	if (!inode)
253 		return -ENOSPC;
254 
255 	inode->i_mode = mode;
256 	affs_mode_to_prot(inode);
257 	mark_inode_dirty(inode);
258 
259 	inode->i_op = &affs_file_inode_operations;
260 	inode->i_fop = &affs_file_operations;
261 	inode->i_mapping->a_ops = affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS) ?
262 				  &affs_aops_ofs : &affs_aops;
263 	error = affs_add_entry(dir, inode, dentry, ST_FILE);
264 	if (error) {
265 		clear_nlink(inode);
266 		iput(inode);
267 		return error;
268 	}
269 	return 0;
270 }
271 
272 int
273 affs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
274 {
275 	struct inode		*inode;
276 	int			 error;
277 
278 	pr_debug("%s(%lu,\"%pd\",0%ho)\n",
279 		 __func__, dir->i_ino, dentry, mode);
280 
281 	inode = affs_new_inode(dir);
282 	if (!inode)
283 		return -ENOSPC;
284 
285 	inode->i_mode = S_IFDIR | mode;
286 	affs_mode_to_prot(inode);
287 
288 	inode->i_op = &affs_dir_inode_operations;
289 	inode->i_fop = &affs_dir_operations;
290 
291 	error = affs_add_entry(dir, inode, dentry, ST_USERDIR);
292 	if (error) {
293 		clear_nlink(inode);
294 		mark_inode_dirty(inode);
295 		iput(inode);
296 		return error;
297 	}
298 	return 0;
299 }
300 
301 int
302 affs_rmdir(struct inode *dir, struct dentry *dentry)
303 {
304 	pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
305 		 d_inode(dentry)->i_ino, dentry);
306 
307 	return affs_remove_header(dentry);
308 }
309 
310 int
311 affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
312 {
313 	struct super_block	*sb = dir->i_sb;
314 	struct buffer_head	*bh;
315 	struct inode		*inode;
316 	char			*p;
317 	int			 i, maxlen, error;
318 	char			 c, lc;
319 
320 	pr_debug("%s(%lu,\"%pd\" -> \"%s\")\n",
321 		 __func__, dir->i_ino, dentry, symname);
322 
323 	maxlen = AFFS_SB(sb)->s_hashsize * sizeof(u32) - 1;
324 	inode  = affs_new_inode(dir);
325 	if (!inode)
326 		return -ENOSPC;
327 
328 	inode->i_op = &affs_symlink_inode_operations;
329 	inode_nohighmem(inode);
330 	inode->i_data.a_ops = &affs_symlink_aops;
331 	inode->i_mode = S_IFLNK | 0777;
332 	affs_mode_to_prot(inode);
333 
334 	error = -EIO;
335 	bh = affs_bread(sb, inode->i_ino);
336 	if (!bh)
337 		goto err;
338 	i  = 0;
339 	p  = (char *)AFFS_HEAD(bh)->table;
340 	lc = '/';
341 	if (*symname == '/') {
342 		struct affs_sb_info *sbi = AFFS_SB(sb);
343 		while (*symname == '/')
344 			symname++;
345 		spin_lock(&sbi->symlink_lock);
346 		while (sbi->s_volume[i])	/* Cannot overflow */
347 			*p++ = sbi->s_volume[i++];
348 		spin_unlock(&sbi->symlink_lock);
349 	}
350 	while (i < maxlen && (c = *symname++)) {
351 		if (c == '.' && lc == '/' && *symname == '.' && symname[1] == '/') {
352 			*p++ = '/';
353 			i++;
354 			symname += 2;
355 			lc = '/';
356 		} else if (c == '.' && lc == '/' && *symname == '/') {
357 			symname++;
358 			lc = '/';
359 		} else {
360 			*p++ = c;
361 			lc   = c;
362 			i++;
363 		}
364 		if (lc == '/')
365 			while (*symname == '/')
366 				symname++;
367 	}
368 	*p = 0;
369 	inode->i_size = i + 1;
370 	mark_buffer_dirty_inode(bh, inode);
371 	affs_brelse(bh);
372 	mark_inode_dirty(inode);
373 
374 	error = affs_add_entry(dir, inode, dentry, ST_SOFTLINK);
375 	if (error)
376 		goto err;
377 
378 	return 0;
379 
380 err:
381 	clear_nlink(inode);
382 	mark_inode_dirty(inode);
383 	iput(inode);
384 	return error;
385 }
386 
387 int
388 affs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
389 {
390 	struct inode *inode = d_inode(old_dentry);
391 
392 	pr_debug("%s(%lu, %lu, \"%pd\")\n", __func__, inode->i_ino, dir->i_ino,
393 		 dentry);
394 
395 	return affs_add_entry(dir, inode, dentry, ST_LINKFILE);
396 }
397 
398 static int
399 affs_rename(struct inode *old_dir, struct dentry *old_dentry,
400 	    struct inode *new_dir, struct dentry *new_dentry)
401 {
402 	struct super_block *sb = old_dir->i_sb;
403 	struct buffer_head *bh = NULL;
404 	int retval;
405 
406 	retval = affs_check_name(new_dentry->d_name.name,
407 				 new_dentry->d_name.len,
408 				 affs_nofilenametruncate(old_dentry));
409 
410 	if (retval)
411 		return retval;
412 
413 	/* Unlink destination if it already exists */
414 	if (d_really_is_positive(new_dentry)) {
415 		retval = affs_remove_header(new_dentry);
416 		if (retval)
417 			return retval;
418 	}
419 
420 	bh = affs_bread(sb, d_inode(old_dentry)->i_ino);
421 	if (!bh)
422 		return -EIO;
423 
424 	/* Remove header from its parent directory. */
425 	affs_lock_dir(old_dir);
426 	retval = affs_remove_hash(old_dir, bh);
427 	affs_unlock_dir(old_dir);
428 	if (retval)
429 		goto done;
430 
431 	/* And insert it into the new directory with the new name. */
432 	affs_copy_name(AFFS_TAIL(sb, bh)->name, new_dentry);
433 	affs_fix_checksum(sb, bh);
434 	affs_lock_dir(new_dir);
435 	retval = affs_insert_hash(new_dir, bh);
436 	affs_unlock_dir(new_dir);
437 	/* TODO: move it back to old_dir, if error? */
438 
439 done:
440 	mark_buffer_dirty_inode(bh, retval ? old_dir : new_dir);
441 	affs_brelse(bh);
442 	return retval;
443 }
444 
445 static int
446 affs_xrename(struct inode *old_dir, struct dentry *old_dentry,
447 	     struct inode *new_dir, struct dentry *new_dentry)
448 {
449 
450 	struct super_block *sb = old_dir->i_sb;
451 	struct buffer_head *bh_old = NULL;
452 	struct buffer_head *bh_new = NULL;
453 	int retval;
454 
455 	bh_old = affs_bread(sb, d_inode(old_dentry)->i_ino);
456 	if (!bh_old)
457 		return -EIO;
458 
459 	bh_new = affs_bread(sb, d_inode(new_dentry)->i_ino);
460 	if (!bh_new)
461 		return -EIO;
462 
463 	/* Remove old header from its parent directory. */
464 	affs_lock_dir(old_dir);
465 	retval = affs_remove_hash(old_dir, bh_old);
466 	affs_unlock_dir(old_dir);
467 	if (retval)
468 		goto done;
469 
470 	/* Remove new header from its parent directory. */
471 	affs_lock_dir(new_dir);
472 	retval = affs_remove_hash(new_dir, bh_new);
473 	affs_unlock_dir(new_dir);
474 	if (retval)
475 		goto done;
476 
477 	/* Insert old into the new directory with the new name. */
478 	affs_copy_name(AFFS_TAIL(sb, bh_old)->name, new_dentry);
479 	affs_fix_checksum(sb, bh_old);
480 	affs_lock_dir(new_dir);
481 	retval = affs_insert_hash(new_dir, bh_old);
482 	affs_unlock_dir(new_dir);
483 
484 	/* Insert new into the old directory with the old name. */
485 	affs_copy_name(AFFS_TAIL(sb, bh_new)->name, old_dentry);
486 	affs_fix_checksum(sb, bh_new);
487 	affs_lock_dir(old_dir);
488 	retval = affs_insert_hash(old_dir, bh_new);
489 	affs_unlock_dir(old_dir);
490 done:
491 	mark_buffer_dirty_inode(bh_old, new_dir);
492 	mark_buffer_dirty_inode(bh_new, old_dir);
493 	affs_brelse(bh_old);
494 	affs_brelse(bh_new);
495 	return retval;
496 }
497 
498 int affs_rename2(struct inode *old_dir, struct dentry *old_dentry,
499 			struct inode *new_dir, struct dentry *new_dentry,
500 			unsigned int flags)
501 {
502 
503 	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
504 		return -EINVAL;
505 
506 	pr_debug("%s(old=%lu,\"%pd\" to new=%lu,\"%pd\")\n", __func__,
507 		 old_dir->i_ino, old_dentry, new_dir->i_ino, new_dentry);
508 
509 	if (flags & RENAME_EXCHANGE)
510 		return affs_xrename(old_dir, old_dentry, new_dir, new_dentry);
511 
512 	return affs_rename(old_dir, old_dentry, new_dir, new_dentry);
513 }
514 
515 static struct dentry *affs_get_parent(struct dentry *child)
516 {
517 	struct inode *parent;
518 	struct buffer_head *bh;
519 
520 	bh = affs_bread(child->d_sb, d_inode(child)->i_ino);
521 	if (!bh)
522 		return ERR_PTR(-EIO);
523 
524 	parent = affs_iget(child->d_sb,
525 			   be32_to_cpu(AFFS_TAIL(child->d_sb, bh)->parent));
526 	brelse(bh);
527 	if (IS_ERR(parent))
528 		return ERR_CAST(parent);
529 
530 	return d_obtain_alias(parent);
531 }
532 
533 static struct inode *affs_nfs_get_inode(struct super_block *sb, u64 ino,
534 					u32 generation)
535 {
536 	struct inode *inode;
537 
538 	if (!affs_validblock(sb, ino))
539 		return ERR_PTR(-ESTALE);
540 
541 	inode = affs_iget(sb, ino);
542 	if (IS_ERR(inode))
543 		return ERR_CAST(inode);
544 
545 	return inode;
546 }
547 
548 static struct dentry *affs_fh_to_dentry(struct super_block *sb, struct fid *fid,
549 					int fh_len, int fh_type)
550 {
551 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
552 				    affs_nfs_get_inode);
553 }
554 
555 static struct dentry *affs_fh_to_parent(struct super_block *sb, struct fid *fid,
556 					int fh_len, int fh_type)
557 {
558 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
559 				    affs_nfs_get_inode);
560 }
561 
562 const struct export_operations affs_export_ops = {
563 	.fh_to_dentry = affs_fh_to_dentry,
564 	.fh_to_parent = affs_fh_to_parent,
565 	.get_parent = affs_get_parent,
566 };
567 
568 const struct dentry_operations affs_dentry_operations = {
569 	.d_hash		= affs_hash_dentry,
570 	.d_compare	= affs_compare_dentry,
571 };
572 
573 const struct dentry_operations affs_intl_dentry_operations = {
574 	.d_hash		= affs_intl_hash_dentry,
575 	.d_compare	= affs_intl_compare_dentry,
576 };
577