1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/fs/affs/amigaffs.c
4  *
5  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
6  *
7  *  (C) 1993  Ray Burr - Amiga FFS filesystem.
8  *
9  *  Please send bug reports to: hjw@zvw.de
10  */
11 
12 #include <linux/math64.h>
13 #include <linux/iversion.h>
14 #include "affs.h"
15 
16 /*
17  * Functions for accessing Amiga-FFS structures.
18  */
19 
20 
21 /* Insert a header block bh into the directory dir
22  * caller must hold AFFS_DIR->i_hash_lock!
23  */
24 
25 int
affs_insert_hash(struct inode * dir,struct buffer_head * bh)26 affs_insert_hash(struct inode *dir, struct buffer_head *bh)
27 {
28 	struct super_block *sb = dir->i_sb;
29 	struct buffer_head *dir_bh;
30 	u32 ino, hash_ino;
31 	int offset;
32 
33 	ino = bh->b_blocknr;
34 	offset = affs_hash_name(sb, AFFS_TAIL(sb, bh)->name + 1, AFFS_TAIL(sb, bh)->name[0]);
35 
36 	pr_debug("%s(dir=%lu, ino=%d)\n", __func__, dir->i_ino, ino);
37 
38 	dir_bh = affs_bread(sb, dir->i_ino);
39 	if (!dir_bh)
40 		return -EIO;
41 
42 	hash_ino = be32_to_cpu(AFFS_HEAD(dir_bh)->table[offset]);
43 	while (hash_ino) {
44 		affs_brelse(dir_bh);
45 		dir_bh = affs_bread(sb, hash_ino);
46 		if (!dir_bh)
47 			return -EIO;
48 		hash_ino = be32_to_cpu(AFFS_TAIL(sb, dir_bh)->hash_chain);
49 	}
50 	AFFS_TAIL(sb, bh)->parent = cpu_to_be32(dir->i_ino);
51 	AFFS_TAIL(sb, bh)->hash_chain = 0;
52 	affs_fix_checksum(sb, bh);
53 
54 	if (dir->i_ino == dir_bh->b_blocknr)
55 		AFFS_HEAD(dir_bh)->table[offset] = cpu_to_be32(ino);
56 	else
57 		AFFS_TAIL(sb, dir_bh)->hash_chain = cpu_to_be32(ino);
58 
59 	affs_adjust_checksum(dir_bh, ino);
60 	mark_buffer_dirty_inode(dir_bh, dir);
61 	affs_brelse(dir_bh);
62 
63 	dir->i_mtime = dir->i_ctime = current_time(dir);
64 	inode_inc_iversion(dir);
65 	mark_inode_dirty(dir);
66 
67 	return 0;
68 }
69 
70 /* Remove a header block from its directory.
71  * caller must hold AFFS_DIR->i_hash_lock!
72  */
73 
74 int
affs_remove_hash(struct inode * dir,struct buffer_head * rem_bh)75 affs_remove_hash(struct inode *dir, struct buffer_head *rem_bh)
76 {
77 	struct super_block *sb;
78 	struct buffer_head *bh;
79 	u32 rem_ino, hash_ino;
80 	__be32 ino;
81 	int offset, retval;
82 
83 	sb = dir->i_sb;
84 	rem_ino = rem_bh->b_blocknr;
85 	offset = affs_hash_name(sb, AFFS_TAIL(sb, rem_bh)->name+1, AFFS_TAIL(sb, rem_bh)->name[0]);
86 	pr_debug("%s(dir=%lu, ino=%d, hashval=%d)\n", __func__, dir->i_ino,
87 		 rem_ino, offset);
88 
89 	bh = affs_bread(sb, dir->i_ino);
90 	if (!bh)
91 		return -EIO;
92 
93 	retval = -ENOENT;
94 	hash_ino = be32_to_cpu(AFFS_HEAD(bh)->table[offset]);
95 	while (hash_ino) {
96 		if (hash_ino == rem_ino) {
97 			ino = AFFS_TAIL(sb, rem_bh)->hash_chain;
98 			if (dir->i_ino == bh->b_blocknr)
99 				AFFS_HEAD(bh)->table[offset] = ino;
100 			else
101 				AFFS_TAIL(sb, bh)->hash_chain = ino;
102 			affs_adjust_checksum(bh, be32_to_cpu(ino) - hash_ino);
103 			mark_buffer_dirty_inode(bh, dir);
104 			AFFS_TAIL(sb, rem_bh)->parent = 0;
105 			retval = 0;
106 			break;
107 		}
108 		affs_brelse(bh);
109 		bh = affs_bread(sb, hash_ino);
110 		if (!bh)
111 			return -EIO;
112 		hash_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
113 	}
114 
115 	affs_brelse(bh);
116 
117 	dir->i_mtime = dir->i_ctime = current_time(dir);
118 	inode_inc_iversion(dir);
119 	mark_inode_dirty(dir);
120 
121 	return retval;
122 }
123 
124 static void
affs_fix_dcache(struct inode * inode,u32 entry_ino)125 affs_fix_dcache(struct inode *inode, u32 entry_ino)
126 {
127 	struct dentry *dentry;
128 	spin_lock(&inode->i_lock);
129 	hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
130 		if (entry_ino == (u32)(long)dentry->d_fsdata) {
131 			dentry->d_fsdata = (void *)inode->i_ino;
132 			break;
133 		}
134 	}
135 	spin_unlock(&inode->i_lock);
136 }
137 
138 
139 /* Remove header from link chain */
140 
141 static int
affs_remove_link(struct dentry * dentry)142 affs_remove_link(struct dentry *dentry)
143 {
144 	struct inode *dir, *inode = d_inode(dentry);
145 	struct super_block *sb = inode->i_sb;
146 	struct buffer_head *bh, *link_bh = NULL;
147 	u32 link_ino, ino;
148 	int retval;
149 
150 	pr_debug("%s(key=%ld)\n", __func__, inode->i_ino);
151 	retval = -EIO;
152 	bh = affs_bread(sb, inode->i_ino);
153 	if (!bh)
154 		goto done;
155 
156 	link_ino = (u32)(long)dentry->d_fsdata;
157 	if (inode->i_ino == link_ino) {
158 		/* we can't remove the head of the link, as its blocknr is still used as ino,
159 		 * so we remove the block of the first link instead.
160 		 */
161 		link_ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain);
162 		link_bh = affs_bread(sb, link_ino);
163 		if (!link_bh)
164 			goto done;
165 
166 		dir = affs_iget(sb, be32_to_cpu(AFFS_TAIL(sb, link_bh)->parent));
167 		if (IS_ERR(dir)) {
168 			retval = PTR_ERR(dir);
169 			goto done;
170 		}
171 
172 		affs_lock_dir(dir);
173 		/*
174 		 * if there's a dentry for that block, make it
175 		 * refer to inode itself.
176 		 */
177 		affs_fix_dcache(inode, link_ino);
178 		retval = affs_remove_hash(dir, link_bh);
179 		if (retval) {
180 			affs_unlock_dir(dir);
181 			goto done;
182 		}
183 		mark_buffer_dirty_inode(link_bh, inode);
184 
185 		memcpy(AFFS_TAIL(sb, bh)->name, AFFS_TAIL(sb, link_bh)->name, 32);
186 		retval = affs_insert_hash(dir, bh);
187 		if (retval) {
188 			affs_unlock_dir(dir);
189 			goto done;
190 		}
191 		mark_buffer_dirty_inode(bh, inode);
192 
193 		affs_unlock_dir(dir);
194 		iput(dir);
195 	} else {
196 		link_bh = affs_bread(sb, link_ino);
197 		if (!link_bh)
198 			goto done;
199 	}
200 
201 	while ((ino = be32_to_cpu(AFFS_TAIL(sb, bh)->link_chain)) != 0) {
202 		if (ino == link_ino) {
203 			__be32 ino2 = AFFS_TAIL(sb, link_bh)->link_chain;
204 			AFFS_TAIL(sb, bh)->link_chain = ino2;
205 			affs_adjust_checksum(bh, be32_to_cpu(ino2) - link_ino);
206 			mark_buffer_dirty_inode(bh, inode);
207 			retval = 0;
208 			/* Fix the link count, if bh is a normal header block without links */
209 			switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
210 			case ST_LINKDIR:
211 			case ST_LINKFILE:
212 				break;
213 			default:
214 				if (!AFFS_TAIL(sb, bh)->link_chain)
215 					set_nlink(inode, 1);
216 			}
217 			affs_free_block(sb, link_ino);
218 			goto done;
219 		}
220 		affs_brelse(bh);
221 		bh = affs_bread(sb, ino);
222 		if (!bh)
223 			goto done;
224 	}
225 	retval = -ENOENT;
226 done:
227 	affs_brelse(link_bh);
228 	affs_brelse(bh);
229 	return retval;
230 }
231 
232 
233 static int
affs_empty_dir(struct inode * inode)234 affs_empty_dir(struct inode *inode)
235 {
236 	struct super_block *sb = inode->i_sb;
237 	struct buffer_head *bh;
238 	int retval, size;
239 
240 	retval = -EIO;
241 	bh = affs_bread(sb, inode->i_ino);
242 	if (!bh)
243 		goto done;
244 
245 	retval = -ENOTEMPTY;
246 	for (size = AFFS_SB(sb)->s_hashsize - 1; size >= 0; size--)
247 		if (AFFS_HEAD(bh)->table[size])
248 			goto not_empty;
249 	retval = 0;
250 not_empty:
251 	affs_brelse(bh);
252 done:
253 	return retval;
254 }
255 
256 
257 /* Remove a filesystem object. If the object to be removed has
258  * links to it, one of the links must be changed to inherit
259  * the file or directory. As above, any inode will do.
260  * The buffer will not be freed. If the header is a link, the
261  * block will be marked as free.
262  * This function returns a negative error number in case of
263  * an error, else 0 if the inode is to be deleted or 1 if not.
264  */
265 
266 int
affs_remove_header(struct dentry * dentry)267 affs_remove_header(struct dentry *dentry)
268 {
269 	struct super_block *sb;
270 	struct inode *inode, *dir;
271 	struct buffer_head *bh = NULL;
272 	int retval;
273 
274 	dir = d_inode(dentry->d_parent);
275 	sb = dir->i_sb;
276 
277 	retval = -ENOENT;
278 	inode = d_inode(dentry);
279 	if (!inode)
280 		goto done;
281 
282 	pr_debug("%s(key=%ld)\n", __func__, inode->i_ino);
283 	retval = -EIO;
284 	bh = affs_bread(sb, (u32)(long)dentry->d_fsdata);
285 	if (!bh)
286 		goto done;
287 
288 	affs_lock_link(inode);
289 	affs_lock_dir(dir);
290 	switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
291 	case ST_USERDIR:
292 		/* if we ever want to support links to dirs
293 		 * i_hash_lock of the inode must only be
294 		 * taken after some checks
295 		 */
296 		affs_lock_dir(inode);
297 		retval = affs_empty_dir(inode);
298 		affs_unlock_dir(inode);
299 		if (retval)
300 			goto done_unlock;
301 		break;
302 	default:
303 		break;
304 	}
305 
306 	retval = affs_remove_hash(dir, bh);
307 	if (retval)
308 		goto done_unlock;
309 	mark_buffer_dirty_inode(bh, inode);
310 
311 	affs_unlock_dir(dir);
312 
313 	if (inode->i_nlink > 1)
314 		retval = affs_remove_link(dentry);
315 	else
316 		clear_nlink(inode);
317 	affs_unlock_link(inode);
318 	inode->i_ctime = current_time(inode);
319 	mark_inode_dirty(inode);
320 
321 done:
322 	affs_brelse(bh);
323 	return retval;
324 
325 done_unlock:
326 	affs_unlock_dir(dir);
327 	affs_unlock_link(inode);
328 	goto done;
329 }
330 
331 /* Checksum a block, do various consistency checks and optionally return
332    the blocks type number.  DATA points to the block.  If their pointers
333    are non-null, *PTYPE and *STYPE are set to the primary and secondary
334    block types respectively, *HASHSIZE is set to the size of the hashtable
335    (which lets us calculate the block size).
336    Returns non-zero if the block is not consistent. */
337 
338 u32
affs_checksum_block(struct super_block * sb,struct buffer_head * bh)339 affs_checksum_block(struct super_block *sb, struct buffer_head *bh)
340 {
341 	__be32 *ptr = (__be32 *)bh->b_data;
342 	u32 sum;
343 	int bsize;
344 
345 	sum = 0;
346 	for (bsize = sb->s_blocksize / sizeof(__be32); bsize > 0; bsize--)
347 		sum += be32_to_cpu(*ptr++);
348 	return sum;
349 }
350 
351 /*
352  * Calculate the checksum of a disk block and store it
353  * at the indicated position.
354  */
355 
356 void
affs_fix_checksum(struct super_block * sb,struct buffer_head * bh)357 affs_fix_checksum(struct super_block *sb, struct buffer_head *bh)
358 {
359 	int cnt = sb->s_blocksize / sizeof(__be32);
360 	__be32 *ptr = (__be32 *)bh->b_data;
361 	u32 checksum;
362 	__be32 *checksumptr;
363 
364 	checksumptr = ptr + 5;
365 	*checksumptr = 0;
366 	for (checksum = 0; cnt > 0; ptr++, cnt--)
367 		checksum += be32_to_cpu(*ptr);
368 	*checksumptr = cpu_to_be32(-checksum);
369 }
370 
371 void
affs_secs_to_datestamp(time64_t secs,struct affs_date * ds)372 affs_secs_to_datestamp(time64_t secs, struct affs_date *ds)
373 {
374 	u32	 days;
375 	u32	 minute;
376 	s32	 rem;
377 
378 	secs -= sys_tz.tz_minuteswest * 60 + ((8 * 365 + 2) * 24 * 60 * 60);
379 	if (secs < 0)
380 		secs = 0;
381 	days    = div_s64_rem(secs, 86400, &rem);
382 	minute  = rem / 60;
383 	rem    -= minute * 60;
384 
385 	ds->days = cpu_to_be32(days);
386 	ds->mins = cpu_to_be32(minute);
387 	ds->ticks = cpu_to_be32(rem * 50);
388 }
389 
390 umode_t
affs_prot_to_mode(u32 prot)391 affs_prot_to_mode(u32 prot)
392 {
393 	umode_t mode = 0;
394 
395 	if (!(prot & FIBF_NOWRITE))
396 		mode |= 0200;
397 	if (!(prot & FIBF_NOREAD))
398 		mode |= 0400;
399 	if (!(prot & FIBF_NOEXECUTE))
400 		mode |= 0100;
401 	if (prot & FIBF_GRP_WRITE)
402 		mode |= 0020;
403 	if (prot & FIBF_GRP_READ)
404 		mode |= 0040;
405 	if (prot & FIBF_GRP_EXECUTE)
406 		mode |= 0010;
407 	if (prot & FIBF_OTR_WRITE)
408 		mode |= 0002;
409 	if (prot & FIBF_OTR_READ)
410 		mode |= 0004;
411 	if (prot & FIBF_OTR_EXECUTE)
412 		mode |= 0001;
413 
414 	return mode;
415 }
416 
417 void
affs_mode_to_prot(struct inode * inode)418 affs_mode_to_prot(struct inode *inode)
419 {
420 	u32 prot = AFFS_I(inode)->i_protect;
421 	umode_t mode = inode->i_mode;
422 
423 	/*
424 	 * First, clear all RWED bits for owner, group, other.
425 	 * Then, recalculate them afresh.
426 	 *
427 	 * We'll always clear the delete-inhibit bit for the owner, as that is
428 	 * the classic single-user mode AmigaOS protection bit and we need to
429 	 * stay compatible with all scenarios.
430 	 *
431 	 * Since multi-user AmigaOS is an extension, we'll only set the
432 	 * delete-allow bit if any of the other bits in the same user class
433 	 * (group/other) are used.
434 	 */
435 	prot &= ~(FIBF_NOEXECUTE | FIBF_NOREAD
436 		  | FIBF_NOWRITE | FIBF_NODELETE
437 		  | FIBF_GRP_EXECUTE | FIBF_GRP_READ
438 		  | FIBF_GRP_WRITE   | FIBF_GRP_DELETE
439 		  | FIBF_OTR_EXECUTE | FIBF_OTR_READ
440 		  | FIBF_OTR_WRITE   | FIBF_OTR_DELETE);
441 
442 	/* Classic single-user AmigaOS flags. These are inverted. */
443 	if (!(mode & 0100))
444 		prot |= FIBF_NOEXECUTE;
445 	if (!(mode & 0400))
446 		prot |= FIBF_NOREAD;
447 	if (!(mode & 0200))
448 		prot |= FIBF_NOWRITE;
449 
450 	/* Multi-user extended flags. Not inverted. */
451 	if (mode & 0010)
452 		prot |= FIBF_GRP_EXECUTE;
453 	if (mode & 0040)
454 		prot |= FIBF_GRP_READ;
455 	if (mode & 0020)
456 		prot |= FIBF_GRP_WRITE;
457 	if (mode & 0070)
458 		prot |= FIBF_GRP_DELETE;
459 
460 	if (mode & 0001)
461 		prot |= FIBF_OTR_EXECUTE;
462 	if (mode & 0004)
463 		prot |= FIBF_OTR_READ;
464 	if (mode & 0002)
465 		prot |= FIBF_OTR_WRITE;
466 	if (mode & 0007)
467 		prot |= FIBF_OTR_DELETE;
468 
469 	AFFS_I(inode)->i_protect = prot;
470 }
471 
472 void
affs_error(struct super_block * sb,const char * function,const char * fmt,...)473 affs_error(struct super_block *sb, const char *function, const char *fmt, ...)
474 {
475 	struct va_format vaf;
476 	va_list args;
477 
478 	va_start(args, fmt);
479 	vaf.fmt = fmt;
480 	vaf.va = &args;
481 	pr_crit("error (device %s): %s(): %pV\n", sb->s_id, function, &vaf);
482 	if (!sb_rdonly(sb))
483 		pr_warn("Remounting filesystem read-only\n");
484 	sb->s_flags |= SB_RDONLY;
485 	va_end(args);
486 }
487 
488 void
affs_warning(struct super_block * sb,const char * function,const char * fmt,...)489 affs_warning(struct super_block *sb, const char *function, const char *fmt, ...)
490 {
491 	struct va_format vaf;
492 	va_list args;
493 
494 	va_start(args, fmt);
495 	vaf.fmt = fmt;
496 	vaf.va = &args;
497 	pr_warn("(device %s): %s(): %pV\n", sb->s_id, function, &vaf);
498 	va_end(args);
499 }
500 
501 bool
affs_nofilenametruncate(const struct dentry * dentry)502 affs_nofilenametruncate(const struct dentry *dentry)
503 {
504 	return affs_test_opt(AFFS_SB(dentry->d_sb)->s_flags, SF_NO_TRUNCATE);
505 }
506 
507 /* Check if the name is valid for a affs object. */
508 
509 int
affs_check_name(const unsigned char * name,int len,bool notruncate)510 affs_check_name(const unsigned char *name, int len, bool notruncate)
511 {
512 	int	 i;
513 
514 	if (len > AFFSNAMEMAX) {
515 		if (notruncate)
516 			return -ENAMETOOLONG;
517 		len = AFFSNAMEMAX;
518 	}
519 	for (i = 0; i < len; i++) {
520 		if (name[i] < ' ' || name[i] == ':'
521 		    || (name[i] > 0x7e && name[i] < 0xa0))
522 			return -EINVAL;
523 	}
524 
525 	return 0;
526 }
527 
528 /* This function copies name to bstr, with at most 30
529  * characters length. The bstr will be prepended by
530  * a length byte.
531  * NOTE: The name will must be already checked by
532  *       affs_check_name()!
533  */
534 
535 int
affs_copy_name(unsigned char * bstr,struct dentry * dentry)536 affs_copy_name(unsigned char *bstr, struct dentry *dentry)
537 {
538 	u32 len = min(dentry->d_name.len, AFFSNAMEMAX);
539 
540 	*bstr++ = len;
541 	memcpy(bstr, dentry->d_name.name, len);
542 	return len;
543 }
544