xref: /openbmc/linux/fs/affs/namei.c (revision b8d312aa) 
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 	struct dentry *res;
205 
206 	pr_debug("%s(\"%pd\")\n", __func__, dentry);
207 
208 	affs_lock_dir(dir);
209 	bh = affs_find_entry(dir, dentry);
210 	if (IS_ERR(bh)) {
211 		affs_unlock_dir(dir);
212 		return ERR_CAST(bh);
213 	}
214 	if (bh) {
215 		u32 ino = bh->b_blocknr;
216 
217 		/* store the real header ino in d_fsdata for faster lookups */
218 		dentry->d_fsdata = (void *)(long)ino;
219 		switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
220 		//link to dirs disabled
221 		//case ST_LINKDIR:
222 		case ST_LINKFILE:
223 			ino = be32_to_cpu(AFFS_TAIL(sb, bh)->original);
224 		}
225 		affs_brelse(bh);
226 		inode = affs_iget(sb, ino);
227 	}
228 	res = d_splice_alias(inode, dentry);
229 	if (!IS_ERR_OR_NULL(res))
230 		res->d_fsdata = dentry->d_fsdata;
231 	affs_unlock_dir(dir);
232 	return res;
233 }
234 
235 int
236 affs_unlink(struct inode *dir, struct dentry *dentry)
237 {
238 	pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
239 		 d_inode(dentry)->i_ino, dentry);
240 
241 	return affs_remove_header(dentry);
242 }
243 
244 int
245 affs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
246 {
247 	struct super_block *sb = dir->i_sb;
248 	struct inode	*inode;
249 	int		 error;
250 
251 	pr_debug("%s(%lu,\"%pd\",0%ho)\n",
252 		 __func__, dir->i_ino, dentry, mode);
253 
254 	inode = affs_new_inode(dir);
255 	if (!inode)
256 		return -ENOSPC;
257 
258 	inode->i_mode = mode;
259 	affs_mode_to_prot(inode);
260 	mark_inode_dirty(inode);
261 
262 	inode->i_op = &affs_file_inode_operations;
263 	inode->i_fop = &affs_file_operations;
264 	inode->i_mapping->a_ops = affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS) ?
265 				  &affs_aops_ofs : &affs_aops;
266 	error = affs_add_entry(dir, inode, dentry, ST_FILE);
267 	if (error) {
268 		clear_nlink(inode);
269 		iput(inode);
270 		return error;
271 	}
272 	return 0;
273 }
274 
275 int
276 affs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
277 {
278 	struct inode		*inode;
279 	int			 error;
280 
281 	pr_debug("%s(%lu,\"%pd\",0%ho)\n",
282 		 __func__, dir->i_ino, dentry, mode);
283 
284 	inode = affs_new_inode(dir);
285 	if (!inode)
286 		return -ENOSPC;
287 
288 	inode->i_mode = S_IFDIR | mode;
289 	affs_mode_to_prot(inode);
290 
291 	inode->i_op = &affs_dir_inode_operations;
292 	inode->i_fop = &affs_dir_operations;
293 
294 	error = affs_add_entry(dir, inode, dentry, ST_USERDIR);
295 	if (error) {
296 		clear_nlink(inode);
297 		mark_inode_dirty(inode);
298 		iput(inode);
299 		return error;
300 	}
301 	return 0;
302 }
303 
304 int
305 affs_rmdir(struct inode *dir, struct dentry *dentry)
306 {
307 	pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
308 		 d_inode(dentry)->i_ino, dentry);
309 
310 	return affs_remove_header(dentry);
311 }
312 
313 int
314 affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
315 {
316 	struct super_block	*sb = dir->i_sb;
317 	struct buffer_head	*bh;
318 	struct inode		*inode;
319 	char			*p;
320 	int			 i, maxlen, error;
321 	char			 c, lc;
322 
323 	pr_debug("%s(%lu,\"%pd\" -> \"%s\")\n",
324 		 __func__, dir->i_ino, dentry, symname);
325 
326 	maxlen = AFFS_SB(sb)->s_hashsize * sizeof(u32) - 1;
327 	inode  = affs_new_inode(dir);
328 	if (!inode)
329 		return -ENOSPC;
330 
331 	inode->i_op = &affs_symlink_inode_operations;
332 	inode_nohighmem(inode);
333 	inode->i_data.a_ops = &affs_symlink_aops;
334 	inode->i_mode = S_IFLNK | 0777;
335 	affs_mode_to_prot(inode);
336 
337 	error = -EIO;
338 	bh = affs_bread(sb, inode->i_ino);
339 	if (!bh)
340 		goto err;
341 	i  = 0;
342 	p  = (char *)AFFS_HEAD(bh)->table;
343 	lc = '/';
344 	if (*symname == '/') {
345 		struct affs_sb_info *sbi = AFFS_SB(sb);
346 		while (*symname == '/')
347 			symname++;
348 		spin_lock(&sbi->symlink_lock);
349 		while (sbi->s_volume[i])	/* Cannot overflow */
350 			*p++ = sbi->s_volume[i++];
351 		spin_unlock(&sbi->symlink_lock);
352 	}
353 	while (i < maxlen && (c = *symname++)) {
354 		if (c == '.' && lc == '/' && *symname == '.' && symname[1] == '/') {
355 			*p++ = '/';
356 			i++;
357 			symname += 2;
358 			lc = '/';
359 		} else if (c == '.' && lc == '/' && *symname == '/') {
360 			symname++;
361 			lc = '/';
362 		} else {
363 			*p++ = c;
364 			lc   = c;
365 			i++;
366 		}
367 		if (lc == '/')
368 			while (*symname == '/')
369 				symname++;
370 	}
371 	*p = 0;
372 	inode->i_size = i + 1;
373 	mark_buffer_dirty_inode(bh, inode);
374 	affs_brelse(bh);
375 	mark_inode_dirty(inode);
376 
377 	error = affs_add_entry(dir, inode, dentry, ST_SOFTLINK);
378 	if (error)
379 		goto err;
380 
381 	return 0;
382 
383 err:
384 	clear_nlink(inode);
385 	mark_inode_dirty(inode);
386 	iput(inode);
387 	return error;
388 }
389 
390 int
391 affs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
392 {
393 	struct inode *inode = d_inode(old_dentry);
394 
395 	pr_debug("%s(%lu, %lu, \"%pd\")\n", __func__, inode->i_ino, dir->i_ino,
396 		 dentry);
397 
398 	return affs_add_entry(dir, inode, dentry, ST_LINKFILE);
399 }
400 
401 static int
402 affs_rename(struct inode *old_dir, struct dentry *old_dentry,
403 	    struct inode *new_dir, struct dentry *new_dentry)
404 {
405 	struct super_block *sb = old_dir->i_sb;
406 	struct buffer_head *bh = NULL;
407 	int retval;
408 
409 	retval = affs_check_name(new_dentry->d_name.name,
410 				 new_dentry->d_name.len,
411 				 affs_nofilenametruncate(old_dentry));
412 
413 	if (retval)
414 		return retval;
415 
416 	/* Unlink destination if it already exists */
417 	if (d_really_is_positive(new_dentry)) {
418 		retval = affs_remove_header(new_dentry);
419 		if (retval)
420 			return retval;
421 	}
422 
423 	bh = affs_bread(sb, d_inode(old_dentry)->i_ino);
424 	if (!bh)
425 		return -EIO;
426 
427 	/* Remove header from its parent directory. */
428 	affs_lock_dir(old_dir);
429 	retval = affs_remove_hash(old_dir, bh);
430 	affs_unlock_dir(old_dir);
431 	if (retval)
432 		goto done;
433 
434 	/* And insert it into the new directory with the new name. */
435 	affs_copy_name(AFFS_TAIL(sb, bh)->name, new_dentry);
436 	affs_fix_checksum(sb, bh);
437 	affs_lock_dir(new_dir);
438 	retval = affs_insert_hash(new_dir, bh);
439 	affs_unlock_dir(new_dir);
440 	/* TODO: move it back to old_dir, if error? */
441 
442 done:
443 	mark_buffer_dirty_inode(bh, retval ? old_dir : new_dir);
444 	affs_brelse(bh);
445 	return retval;
446 }
447 
448 static int
449 affs_xrename(struct inode *old_dir, struct dentry *old_dentry,
450 	     struct inode *new_dir, struct dentry *new_dentry)
451 {
452 
453 	struct super_block *sb = old_dir->i_sb;
454 	struct buffer_head *bh_old = NULL;
455 	struct buffer_head *bh_new = NULL;
456 	int retval;
457 
458 	bh_old = affs_bread(sb, d_inode(old_dentry)->i_ino);
459 	if (!bh_old)
460 		return -EIO;
461 
462 	bh_new = affs_bread(sb, d_inode(new_dentry)->i_ino);
463 	if (!bh_new)
464 		return -EIO;
465 
466 	/* Remove old header from its parent directory. */
467 	affs_lock_dir(old_dir);
468 	retval = affs_remove_hash(old_dir, bh_old);
469 	affs_unlock_dir(old_dir);
470 	if (retval)
471 		goto done;
472 
473 	/* Remove new header from its parent directory. */
474 	affs_lock_dir(new_dir);
475 	retval = affs_remove_hash(new_dir, bh_new);
476 	affs_unlock_dir(new_dir);
477 	if (retval)
478 		goto done;
479 
480 	/* Insert old into the new directory with the new name. */
481 	affs_copy_name(AFFS_TAIL(sb, bh_old)->name, new_dentry);
482 	affs_fix_checksum(sb, bh_old);
483 	affs_lock_dir(new_dir);
484 	retval = affs_insert_hash(new_dir, bh_old);
485 	affs_unlock_dir(new_dir);
486 
487 	/* Insert new into the old directory with the old name. */
488 	affs_copy_name(AFFS_TAIL(sb, bh_new)->name, old_dentry);
489 	affs_fix_checksum(sb, bh_new);
490 	affs_lock_dir(old_dir);
491 	retval = affs_insert_hash(old_dir, bh_new);
492 	affs_unlock_dir(old_dir);
493 done:
494 	mark_buffer_dirty_inode(bh_old, new_dir);
495 	mark_buffer_dirty_inode(bh_new, old_dir);
496 	affs_brelse(bh_old);
497 	affs_brelse(bh_new);
498 	return retval;
499 }
500 
501 int affs_rename2(struct inode *old_dir, struct dentry *old_dentry,
502 			struct inode *new_dir, struct dentry *new_dentry,
503 			unsigned int flags)
504 {
505 
506 	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
507 		return -EINVAL;
508 
509 	pr_debug("%s(old=%lu,\"%pd\" to new=%lu,\"%pd\")\n", __func__,
510 		 old_dir->i_ino, old_dentry, new_dir->i_ino, new_dentry);
511 
512 	if (flags & RENAME_EXCHANGE)
513 		return affs_xrename(old_dir, old_dentry, new_dir, new_dentry);
514 
515 	return affs_rename(old_dir, old_dentry, new_dir, new_dentry);
516 }
517 
518 static struct dentry *affs_get_parent(struct dentry *child)
519 {
520 	struct inode *parent;
521 	struct buffer_head *bh;
522 
523 	bh = affs_bread(child->d_sb, d_inode(child)->i_ino);
524 	if (!bh)
525 		return ERR_PTR(-EIO);
526 
527 	parent = affs_iget(child->d_sb,
528 			   be32_to_cpu(AFFS_TAIL(child->d_sb, bh)->parent));
529 	brelse(bh);
530 	if (IS_ERR(parent))
531 		return ERR_CAST(parent);
532 
533 	return d_obtain_alias(parent);
534 }
535 
536 static struct inode *affs_nfs_get_inode(struct super_block *sb, u64 ino,
537 					u32 generation)
538 {
539 	struct inode *inode;
540 
541 	if (!affs_validblock(sb, ino))
542 		return ERR_PTR(-ESTALE);
543 
544 	inode = affs_iget(sb, ino);
545 	if (IS_ERR(inode))
546 		return ERR_CAST(inode);
547 
548 	return inode;
549 }
550 
551 static struct dentry *affs_fh_to_dentry(struct super_block *sb, struct fid *fid,
552 					int fh_len, int fh_type)
553 {
554 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
555 				    affs_nfs_get_inode);
556 }
557 
558 static struct dentry *affs_fh_to_parent(struct super_block *sb, struct fid *fid,
559 					int fh_len, int fh_type)
560 {
561 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
562 				    affs_nfs_get_inode);
563 }
564 
565 const struct export_operations affs_export_ops = {
566 	.fh_to_dentry = affs_fh_to_dentry,
567 	.fh_to_parent = affs_fh_to_parent,
568 	.get_parent = affs_get_parent,
569 };
570 
571 const struct dentry_operations affs_dentry_operations = {
572 	.d_hash		= affs_hash_dentry,
573 	.d_compare	= affs_compare_dentry,
574 };
575 
576 const struct dentry_operations affs_intl_dentry_operations = {
577 	.d_hash		= affs_intl_hash_dentry,
578 	.d_compare	= affs_intl_compare_dentry,
579 };
580