xref: /openbmc/linux/fs/affs/namei.c (revision 8938c48f) 
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 user_namespace *mnt_userns, struct inode *dir,
246 	    struct dentry *dentry, umode_t mode, bool excl)
247 {
248 	struct super_block *sb = dir->i_sb;
249 	struct inode	*inode;
250 	int		 error;
251 
252 	pr_debug("%s(%lu,\"%pd\",0%ho)\n",
253 		 __func__, dir->i_ino, dentry, mode);
254 
255 	inode = affs_new_inode(dir);
256 	if (!inode)
257 		return -ENOSPC;
258 
259 	inode->i_mode = mode;
260 	affs_mode_to_prot(inode);
261 	mark_inode_dirty(inode);
262 
263 	inode->i_op = &affs_file_inode_operations;
264 	inode->i_fop = &affs_file_operations;
265 	inode->i_mapping->a_ops = affs_test_opt(AFFS_SB(sb)->s_flags, SF_OFS) ?
266 				  &affs_aops_ofs : &affs_aops;
267 	error = affs_add_entry(dir, inode, dentry, ST_FILE);
268 	if (error) {
269 		clear_nlink(inode);
270 		iput(inode);
271 		return error;
272 	}
273 	return 0;
274 }
275 
276 int
277 affs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
278 	   struct dentry *dentry, umode_t mode)
279 {
280 	struct inode		*inode;
281 	int			 error;
282 
283 	pr_debug("%s(%lu,\"%pd\",0%ho)\n",
284 		 __func__, dir->i_ino, dentry, mode);
285 
286 	inode = affs_new_inode(dir);
287 	if (!inode)
288 		return -ENOSPC;
289 
290 	inode->i_mode = S_IFDIR | mode;
291 	affs_mode_to_prot(inode);
292 
293 	inode->i_op = &affs_dir_inode_operations;
294 	inode->i_fop = &affs_dir_operations;
295 
296 	error = affs_add_entry(dir, inode, dentry, ST_USERDIR);
297 	if (error) {
298 		clear_nlink(inode);
299 		mark_inode_dirty(inode);
300 		iput(inode);
301 		return error;
302 	}
303 	return 0;
304 }
305 
306 int
307 affs_rmdir(struct inode *dir, struct dentry *dentry)
308 {
309 	pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
310 		 d_inode(dentry)->i_ino, dentry);
311 
312 	return affs_remove_header(dentry);
313 }
314 
315 int
316 affs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
317 	     struct dentry *dentry, const char *symname)
318 {
319 	struct super_block	*sb = dir->i_sb;
320 	struct buffer_head	*bh;
321 	struct inode		*inode;
322 	char			*p;
323 	int			 i, maxlen, error;
324 	char			 c, lc;
325 
326 	pr_debug("%s(%lu,\"%pd\" -> \"%s\")\n",
327 		 __func__, dir->i_ino, dentry, symname);
328 
329 	maxlen = AFFS_SB(sb)->s_hashsize * sizeof(u32) - 1;
330 	inode  = affs_new_inode(dir);
331 	if (!inode)
332 		return -ENOSPC;
333 
334 	inode->i_op = &affs_symlink_inode_operations;
335 	inode_nohighmem(inode);
336 	inode->i_data.a_ops = &affs_symlink_aops;
337 	inode->i_mode = S_IFLNK | 0777;
338 	affs_mode_to_prot(inode);
339 
340 	error = -EIO;
341 	bh = affs_bread(sb, inode->i_ino);
342 	if (!bh)
343 		goto err;
344 	i  = 0;
345 	p  = (char *)AFFS_HEAD(bh)->table;
346 	lc = '/';
347 	if (*symname == '/') {
348 		struct affs_sb_info *sbi = AFFS_SB(sb);
349 		while (*symname == '/')
350 			symname++;
351 		spin_lock(&sbi->symlink_lock);
352 		while (sbi->s_volume[i])	/* Cannot overflow */
353 			*p++ = sbi->s_volume[i++];
354 		spin_unlock(&sbi->symlink_lock);
355 	}
356 	while (i < maxlen && (c = *symname++)) {
357 		if (c == '.' && lc == '/' && *symname == '.' && symname[1] == '/') {
358 			*p++ = '/';
359 			i++;
360 			symname += 2;
361 			lc = '/';
362 		} else if (c == '.' && lc == '/' && *symname == '/') {
363 			symname++;
364 			lc = '/';
365 		} else {
366 			*p++ = c;
367 			lc   = c;
368 			i++;
369 		}
370 		if (lc == '/')
371 			while (*symname == '/')
372 				symname++;
373 	}
374 	*p = 0;
375 	inode->i_size = i + 1;
376 	mark_buffer_dirty_inode(bh, inode);
377 	affs_brelse(bh);
378 	mark_inode_dirty(inode);
379 
380 	error = affs_add_entry(dir, inode, dentry, ST_SOFTLINK);
381 	if (error)
382 		goto err;
383 
384 	return 0;
385 
386 err:
387 	clear_nlink(inode);
388 	mark_inode_dirty(inode);
389 	iput(inode);
390 	return error;
391 }
392 
393 int
394 affs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
395 {
396 	struct inode *inode = d_inode(old_dentry);
397 
398 	pr_debug("%s(%lu, %lu, \"%pd\")\n", __func__, inode->i_ino, dir->i_ino,
399 		 dentry);
400 
401 	return affs_add_entry(dir, inode, dentry, ST_LINKFILE);
402 }
403 
404 static int
405 affs_rename(struct inode *old_dir, struct dentry *old_dentry,
406 	    struct inode *new_dir, struct dentry *new_dentry)
407 {
408 	struct super_block *sb = old_dir->i_sb;
409 	struct buffer_head *bh = NULL;
410 	int retval;
411 
412 	retval = affs_check_name(new_dentry->d_name.name,
413 				 new_dentry->d_name.len,
414 				 affs_nofilenametruncate(old_dentry));
415 
416 	if (retval)
417 		return retval;
418 
419 	/* Unlink destination if it already exists */
420 	if (d_really_is_positive(new_dentry)) {
421 		retval = affs_remove_header(new_dentry);
422 		if (retval)
423 			return retval;
424 	}
425 
426 	bh = affs_bread(sb, d_inode(old_dentry)->i_ino);
427 	if (!bh)
428 		return -EIO;
429 
430 	/* Remove header from its parent directory. */
431 	affs_lock_dir(old_dir);
432 	retval = affs_remove_hash(old_dir, bh);
433 	affs_unlock_dir(old_dir);
434 	if (retval)
435 		goto done;
436 
437 	/* And insert it into the new directory with the new name. */
438 	affs_copy_name(AFFS_TAIL(sb, bh)->name, new_dentry);
439 	affs_fix_checksum(sb, bh);
440 	affs_lock_dir(new_dir);
441 	retval = affs_insert_hash(new_dir, bh);
442 	affs_unlock_dir(new_dir);
443 	/* TODO: move it back to old_dir, if error? */
444 
445 done:
446 	mark_buffer_dirty_inode(bh, retval ? old_dir : new_dir);
447 	affs_brelse(bh);
448 	return retval;
449 }
450 
451 static int
452 affs_xrename(struct inode *old_dir, struct dentry *old_dentry,
453 	     struct inode *new_dir, struct dentry *new_dentry)
454 {
455 
456 	struct super_block *sb = old_dir->i_sb;
457 	struct buffer_head *bh_old = NULL;
458 	struct buffer_head *bh_new = NULL;
459 	int retval;
460 
461 	bh_old = affs_bread(sb, d_inode(old_dentry)->i_ino);
462 	if (!bh_old)
463 		return -EIO;
464 
465 	bh_new = affs_bread(sb, d_inode(new_dentry)->i_ino);
466 	if (!bh_new) {
467 		affs_brelse(bh_old);
468 		return -EIO;
469 	}
470 
471 	/* Remove old header from its parent directory. */
472 	affs_lock_dir(old_dir);
473 	retval = affs_remove_hash(old_dir, bh_old);
474 	affs_unlock_dir(old_dir);
475 	if (retval)
476 		goto done;
477 
478 	/* Remove new header from its parent directory. */
479 	affs_lock_dir(new_dir);
480 	retval = affs_remove_hash(new_dir, bh_new);
481 	affs_unlock_dir(new_dir);
482 	if (retval)
483 		goto done;
484 
485 	/* Insert old into the new directory with the new name. */
486 	affs_copy_name(AFFS_TAIL(sb, bh_old)->name, new_dentry);
487 	affs_fix_checksum(sb, bh_old);
488 	affs_lock_dir(new_dir);
489 	retval = affs_insert_hash(new_dir, bh_old);
490 	affs_unlock_dir(new_dir);
491 
492 	/* Insert new into the old directory with the old name. */
493 	affs_copy_name(AFFS_TAIL(sb, bh_new)->name, old_dentry);
494 	affs_fix_checksum(sb, bh_new);
495 	affs_lock_dir(old_dir);
496 	retval = affs_insert_hash(old_dir, bh_new);
497 	affs_unlock_dir(old_dir);
498 done:
499 	mark_buffer_dirty_inode(bh_old, new_dir);
500 	mark_buffer_dirty_inode(bh_new, old_dir);
501 	affs_brelse(bh_old);
502 	affs_brelse(bh_new);
503 	return retval;
504 }
505 
506 int affs_rename2(struct user_namespace *mnt_userns, struct inode *old_dir,
507 		 struct dentry *old_dentry, struct inode *new_dir,
508 		 struct dentry *new_dentry, unsigned int flags)
509 {
510 
511 	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
512 		return -EINVAL;
513 
514 	pr_debug("%s(old=%lu,\"%pd\" to new=%lu,\"%pd\")\n", __func__,
515 		 old_dir->i_ino, old_dentry, new_dir->i_ino, new_dentry);
516 
517 	if (flags & RENAME_EXCHANGE)
518 		return affs_xrename(old_dir, old_dentry, new_dir, new_dentry);
519 
520 	return affs_rename(old_dir, old_dentry, new_dir, new_dentry);
521 }
522 
523 static struct dentry *affs_get_parent(struct dentry *child)
524 {
525 	struct inode *parent;
526 	struct buffer_head *bh;
527 
528 	bh = affs_bread(child->d_sb, d_inode(child)->i_ino);
529 	if (!bh)
530 		return ERR_PTR(-EIO);
531 
532 	parent = affs_iget(child->d_sb,
533 			   be32_to_cpu(AFFS_TAIL(child->d_sb, bh)->parent));
534 	brelse(bh);
535 	if (IS_ERR(parent))
536 		return ERR_CAST(parent);
537 
538 	return d_obtain_alias(parent);
539 }
540 
541 static struct inode *affs_nfs_get_inode(struct super_block *sb, u64 ino,
542 					u32 generation)
543 {
544 	struct inode *inode;
545 
546 	if (!affs_validblock(sb, ino))
547 		return ERR_PTR(-ESTALE);
548 
549 	inode = affs_iget(sb, ino);
550 	if (IS_ERR(inode))
551 		return ERR_CAST(inode);
552 
553 	return inode;
554 }
555 
556 static struct dentry *affs_fh_to_dentry(struct super_block *sb, struct fid *fid,
557 					int fh_len, int fh_type)
558 {
559 	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
560 				    affs_nfs_get_inode);
561 }
562 
563 static struct dentry *affs_fh_to_parent(struct super_block *sb, struct fid *fid,
564 					int fh_len, int fh_type)
565 {
566 	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
567 				    affs_nfs_get_inode);
568 }
569 
570 const struct export_operations affs_export_ops = {
571 	.fh_to_dentry = affs_fh_to_dentry,
572 	.fh_to_parent = affs_fh_to_parent,
573 	.get_parent = affs_get_parent,
574 };
575 
576 const struct dentry_operations affs_dentry_operations = {
577 	.d_hash		= affs_hash_dentry,
578 	.d_compare	= affs_compare_dentry,
579 };
580 
581 const struct dentry_operations affs_intl_dentry_operations = {
582 	.d_hash		= affs_intl_hash_dentry,
583 	.d_compare	= affs_intl_compare_dentry,
584 };
585