xref: /openbmc/linux/fs/xfs/xfs_attr_list.c (revision 612a462a)
1 /*
2  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
3  * Copyright (c) 2013 Red Hat, Inc.
4  * All Rights Reserved.
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License as
8  * published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it would be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write the Free Software Foundation,
17  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
18  */
19 #include "xfs.h"
20 #include "xfs_fs.h"
21 #include "xfs_format.h"
22 #include "xfs_log_format.h"
23 #include "xfs_trans_resv.h"
24 #include "xfs_bit.h"
25 #include "xfs_mount.h"
26 #include "xfs_da_format.h"
27 #include "xfs_da_btree.h"
28 #include "xfs_inode.h"
29 #include "xfs_trans.h"
30 #include "xfs_inode_item.h"
31 #include "xfs_bmap.h"
32 #include "xfs_attr.h"
33 #include "xfs_attr_sf.h"
34 #include "xfs_attr_remote.h"
35 #include "xfs_attr_leaf.h"
36 #include "xfs_error.h"
37 #include "xfs_trace.h"
38 #include "xfs_buf_item.h"
39 #include "xfs_cksum.h"
40 #include "xfs_dir2.h"
41 
42 STATIC int
43 xfs_attr_shortform_compare(const void *a, const void *b)
44 {
45 	xfs_attr_sf_sort_t *sa, *sb;
46 
47 	sa = (xfs_attr_sf_sort_t *)a;
48 	sb = (xfs_attr_sf_sort_t *)b;
49 	if (sa->hash < sb->hash) {
50 		return -1;
51 	} else if (sa->hash > sb->hash) {
52 		return 1;
53 	} else {
54 		return sa->entno - sb->entno;
55 	}
56 }
57 
58 #define XFS_ISRESET_CURSOR(cursor) \
59 	(!((cursor)->initted) && !((cursor)->hashval) && \
60 	 !((cursor)->blkno) && !((cursor)->offset))
61 /*
62  * Copy out entries of shortform attribute lists for attr_list().
63  * Shortform attribute lists are not stored in hashval sorted order.
64  * If the output buffer is not large enough to hold them all, then we
65  * we have to calculate each entries' hashvalue and sort them before
66  * we can begin returning them to the user.
67  */
68 static int
69 xfs_attr_shortform_list(xfs_attr_list_context_t *context)
70 {
71 	attrlist_cursor_kern_t *cursor;
72 	xfs_attr_sf_sort_t *sbuf, *sbp;
73 	xfs_attr_shortform_t *sf;
74 	xfs_attr_sf_entry_t *sfe;
75 	xfs_inode_t *dp;
76 	int sbsize, nsbuf, count, i;
77 
78 	ASSERT(context != NULL);
79 	dp = context->dp;
80 	ASSERT(dp != NULL);
81 	ASSERT(dp->i_afp != NULL);
82 	sf = (xfs_attr_shortform_t *)dp->i_afp->if_u1.if_data;
83 	ASSERT(sf != NULL);
84 	if (!sf->hdr.count)
85 		return 0;
86 	cursor = context->cursor;
87 	ASSERT(cursor != NULL);
88 
89 	trace_xfs_attr_list_sf(context);
90 
91 	/*
92 	 * If the buffer is large enough and the cursor is at the start,
93 	 * do not bother with sorting since we will return everything in
94 	 * one buffer and another call using the cursor won't need to be
95 	 * made.
96 	 * Note the generous fudge factor of 16 overhead bytes per entry.
97 	 * If bufsize is zero then put_listent must be a search function
98 	 * and can just scan through what we have.
99 	 */
100 	if (context->bufsize == 0 ||
101 	    (XFS_ISRESET_CURSOR(cursor) &&
102              (dp->i_afp->if_bytes + sf->hdr.count * 16) < context->bufsize)) {
103 		for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
104 			context->put_listent(context,
105 					     sfe->flags,
106 					     sfe->nameval,
107 					     (int)sfe->namelen,
108 					     (int)sfe->valuelen);
109 			/*
110 			 * Either search callback finished early or
111 			 * didn't fit it all in the buffer after all.
112 			 */
113 			if (context->seen_enough)
114 				break;
115 			sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
116 		}
117 		trace_xfs_attr_list_sf_all(context);
118 		return 0;
119 	}
120 
121 	/* do no more for a search callback */
122 	if (context->bufsize == 0)
123 		return 0;
124 
125 	/*
126 	 * It didn't all fit, so we have to sort everything on hashval.
127 	 */
128 	sbsize = sf->hdr.count * sizeof(*sbuf);
129 	sbp = sbuf = kmem_alloc(sbsize, KM_SLEEP | KM_NOFS);
130 
131 	/*
132 	 * Scan the attribute list for the rest of the entries, storing
133 	 * the relevant info from only those that match into a buffer.
134 	 */
135 	nsbuf = 0;
136 	for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
137 		if (unlikely(
138 		    ((char *)sfe < (char *)sf) ||
139 		    ((char *)sfe >= ((char *)sf + dp->i_afp->if_bytes)))) {
140 			XFS_CORRUPTION_ERROR("xfs_attr_shortform_list",
141 					     XFS_ERRLEVEL_LOW,
142 					     context->dp->i_mount, sfe);
143 			kmem_free(sbuf);
144 			return -EFSCORRUPTED;
145 		}
146 
147 		sbp->entno = i;
148 		sbp->hash = xfs_da_hashname(sfe->nameval, sfe->namelen);
149 		sbp->name = sfe->nameval;
150 		sbp->namelen = sfe->namelen;
151 		/* These are bytes, and both on-disk, don't endian-flip */
152 		sbp->valuelen = sfe->valuelen;
153 		sbp->flags = sfe->flags;
154 		sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
155 		sbp++;
156 		nsbuf++;
157 	}
158 
159 	/*
160 	 * Sort the entries on hash then entno.
161 	 */
162 	xfs_sort(sbuf, nsbuf, sizeof(*sbuf), xfs_attr_shortform_compare);
163 
164 	/*
165 	 * Re-find our place IN THE SORTED LIST.
166 	 */
167 	count = 0;
168 	cursor->initted = 1;
169 	cursor->blkno = 0;
170 	for (sbp = sbuf, i = 0; i < nsbuf; i++, sbp++) {
171 		if (sbp->hash == cursor->hashval) {
172 			if (cursor->offset == count) {
173 				break;
174 			}
175 			count++;
176 		} else if (sbp->hash > cursor->hashval) {
177 			break;
178 		}
179 	}
180 	if (i == nsbuf) {
181 		kmem_free(sbuf);
182 		return 0;
183 	}
184 
185 	/*
186 	 * Loop putting entries into the user buffer.
187 	 */
188 	for ( ; i < nsbuf; i++, sbp++) {
189 		if (cursor->hashval != sbp->hash) {
190 			cursor->hashval = sbp->hash;
191 			cursor->offset = 0;
192 		}
193 		context->put_listent(context,
194 				     sbp->flags,
195 				     sbp->name,
196 				     sbp->namelen,
197 				     sbp->valuelen);
198 		if (context->seen_enough)
199 			break;
200 		cursor->offset++;
201 	}
202 
203 	kmem_free(sbuf);
204 	return 0;
205 }
206 
207 STATIC int
208 xfs_attr_node_list(xfs_attr_list_context_t *context)
209 {
210 	attrlist_cursor_kern_t *cursor;
211 	xfs_attr_leafblock_t *leaf;
212 	xfs_da_intnode_t *node;
213 	struct xfs_attr3_icleaf_hdr leafhdr;
214 	struct xfs_da3_icnode_hdr nodehdr;
215 	struct xfs_da_node_entry *btree;
216 	int error, i;
217 	struct xfs_buf *bp;
218 	struct xfs_inode	*dp = context->dp;
219 	struct xfs_mount	*mp = dp->i_mount;
220 
221 	trace_xfs_attr_node_list(context);
222 
223 	cursor = context->cursor;
224 	cursor->initted = 1;
225 
226 	/*
227 	 * Do all sorts of validation on the passed-in cursor structure.
228 	 * If anything is amiss, ignore the cursor and look up the hashval
229 	 * starting from the btree root.
230 	 */
231 	bp = NULL;
232 	if (cursor->blkno > 0) {
233 		error = xfs_da3_node_read(context->tp, dp, cursor->blkno, -1,
234 					      &bp, XFS_ATTR_FORK);
235 		if ((error != 0) && (error != -EFSCORRUPTED))
236 			return error;
237 		if (bp) {
238 			struct xfs_attr_leaf_entry *entries;
239 
240 			node = bp->b_addr;
241 			switch (be16_to_cpu(node->hdr.info.magic)) {
242 			case XFS_DA_NODE_MAGIC:
243 			case XFS_DA3_NODE_MAGIC:
244 				trace_xfs_attr_list_wrong_blk(context);
245 				xfs_trans_brelse(context->tp, bp);
246 				bp = NULL;
247 				break;
248 			case XFS_ATTR_LEAF_MAGIC:
249 			case XFS_ATTR3_LEAF_MAGIC:
250 				leaf = bp->b_addr;
251 				xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo,
252 							     &leafhdr, leaf);
253 				entries = xfs_attr3_leaf_entryp(leaf);
254 				if (cursor->hashval > be32_to_cpu(
255 						entries[leafhdr.count - 1].hashval)) {
256 					trace_xfs_attr_list_wrong_blk(context);
257 					xfs_trans_brelse(context->tp, bp);
258 					bp = NULL;
259 				} else if (cursor->hashval <= be32_to_cpu(
260 						entries[0].hashval)) {
261 					trace_xfs_attr_list_wrong_blk(context);
262 					xfs_trans_brelse(context->tp, bp);
263 					bp = NULL;
264 				}
265 				break;
266 			default:
267 				trace_xfs_attr_list_wrong_blk(context);
268 				xfs_trans_brelse(context->tp, bp);
269 				bp = NULL;
270 			}
271 		}
272 	}
273 
274 	/*
275 	 * We did not find what we expected given the cursor's contents,
276 	 * so we start from the top and work down based on the hash value.
277 	 * Note that start of node block is same as start of leaf block.
278 	 */
279 	if (bp == NULL) {
280 		cursor->blkno = 0;
281 		for (;;) {
282 			uint16_t magic;
283 
284 			error = xfs_da3_node_read(context->tp, dp,
285 						      cursor->blkno, -1, &bp,
286 						      XFS_ATTR_FORK);
287 			if (error)
288 				return error;
289 			node = bp->b_addr;
290 			magic = be16_to_cpu(node->hdr.info.magic);
291 			if (magic == XFS_ATTR_LEAF_MAGIC ||
292 			    magic == XFS_ATTR3_LEAF_MAGIC)
293 				break;
294 			if (magic != XFS_DA_NODE_MAGIC &&
295 			    magic != XFS_DA3_NODE_MAGIC) {
296 				XFS_CORRUPTION_ERROR("xfs_attr_node_list(3)",
297 						     XFS_ERRLEVEL_LOW,
298 						     context->dp->i_mount,
299 						     node);
300 				xfs_trans_brelse(context->tp, bp);
301 				return -EFSCORRUPTED;
302 			}
303 
304 			dp->d_ops->node_hdr_from_disk(&nodehdr, node);
305 			btree = dp->d_ops->node_tree_p(node);
306 			for (i = 0; i < nodehdr.count; btree++, i++) {
307 				if (cursor->hashval
308 						<= be32_to_cpu(btree->hashval)) {
309 					cursor->blkno = be32_to_cpu(btree->before);
310 					trace_xfs_attr_list_node_descend(context,
311 									 btree);
312 					break;
313 				}
314 			}
315 			if (i == nodehdr.count) {
316 				xfs_trans_brelse(context->tp, bp);
317 				return 0;
318 			}
319 			xfs_trans_brelse(context->tp, bp);
320 		}
321 	}
322 	ASSERT(bp != NULL);
323 
324 	/*
325 	 * Roll upward through the blocks, processing each leaf block in
326 	 * order.  As long as there is space in the result buffer, keep
327 	 * adding the information.
328 	 */
329 	for (;;) {
330 		leaf = bp->b_addr;
331 		xfs_attr3_leaf_list_int(bp, context);
332 		xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &leafhdr, leaf);
333 		if (context->seen_enough || leafhdr.forw == 0)
334 			break;
335 		cursor->blkno = leafhdr.forw;
336 		xfs_trans_brelse(context->tp, bp);
337 		error = xfs_attr3_leaf_read(context->tp, dp, cursor->blkno, -1, &bp);
338 		if (error)
339 			return error;
340 	}
341 	xfs_trans_brelse(context->tp, bp);
342 	return 0;
343 }
344 
345 /*
346  * Copy out attribute list entries for attr_list(), for leaf attribute lists.
347  */
348 void
349 xfs_attr3_leaf_list_int(
350 	struct xfs_buf			*bp,
351 	struct xfs_attr_list_context	*context)
352 {
353 	struct attrlist_cursor_kern	*cursor;
354 	struct xfs_attr_leafblock	*leaf;
355 	struct xfs_attr3_icleaf_hdr	ichdr;
356 	struct xfs_attr_leaf_entry	*entries;
357 	struct xfs_attr_leaf_entry	*entry;
358 	int				i;
359 	struct xfs_mount		*mp = context->dp->i_mount;
360 
361 	trace_xfs_attr_list_leaf(context);
362 
363 	leaf = bp->b_addr;
364 	xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &ichdr, leaf);
365 	entries = xfs_attr3_leaf_entryp(leaf);
366 
367 	cursor = context->cursor;
368 	cursor->initted = 1;
369 
370 	/*
371 	 * Re-find our place in the leaf block if this is a new syscall.
372 	 */
373 	if (context->resynch) {
374 		entry = &entries[0];
375 		for (i = 0; i < ichdr.count; entry++, i++) {
376 			if (be32_to_cpu(entry->hashval) == cursor->hashval) {
377 				if (cursor->offset == context->dupcnt) {
378 					context->dupcnt = 0;
379 					break;
380 				}
381 				context->dupcnt++;
382 			} else if (be32_to_cpu(entry->hashval) >
383 					cursor->hashval) {
384 				context->dupcnt = 0;
385 				break;
386 			}
387 		}
388 		if (i == ichdr.count) {
389 			trace_xfs_attr_list_notfound(context);
390 			return;
391 		}
392 	} else {
393 		entry = &entries[0];
394 		i = 0;
395 	}
396 	context->resynch = 0;
397 
398 	/*
399 	 * We have found our place, start copying out the new attributes.
400 	 */
401 	for (; i < ichdr.count; entry++, i++) {
402 		char *name;
403 		int namelen, valuelen;
404 
405 		if (be32_to_cpu(entry->hashval) != cursor->hashval) {
406 			cursor->hashval = be32_to_cpu(entry->hashval);
407 			cursor->offset = 0;
408 		}
409 
410 		if (entry->flags & XFS_ATTR_INCOMPLETE)
411 			continue;		/* skip incomplete entries */
412 
413 		if (entry->flags & XFS_ATTR_LOCAL) {
414 			xfs_attr_leaf_name_local_t *name_loc;
415 
416 			name_loc = xfs_attr3_leaf_name_local(leaf, i);
417 			name = name_loc->nameval;
418 			namelen = name_loc->namelen;
419 			valuelen = be16_to_cpu(name_loc->valuelen);
420 		} else {
421 			xfs_attr_leaf_name_remote_t *name_rmt;
422 
423 			name_rmt = xfs_attr3_leaf_name_remote(leaf, i);
424 			name = name_rmt->name;
425 			namelen = name_rmt->namelen;
426 			valuelen = be32_to_cpu(name_rmt->valuelen);
427 		}
428 
429 		context->put_listent(context, entry->flags,
430 					      name, namelen, valuelen);
431 		if (context->seen_enough)
432 			break;
433 		cursor->offset++;
434 	}
435 	trace_xfs_attr_list_leaf_end(context);
436 	return;
437 }
438 
439 /*
440  * Copy out attribute entries for attr_list(), for leaf attribute lists.
441  */
442 STATIC int
443 xfs_attr_leaf_list(xfs_attr_list_context_t *context)
444 {
445 	int error;
446 	struct xfs_buf *bp;
447 
448 	trace_xfs_attr_leaf_list(context);
449 
450 	context->cursor->blkno = 0;
451 	error = xfs_attr3_leaf_read(context->tp, context->dp, 0, -1, &bp);
452 	if (error)
453 		return error;
454 
455 	xfs_attr3_leaf_list_int(bp, context);
456 	xfs_trans_brelse(context->tp, bp);
457 	return 0;
458 }
459 
460 int
461 xfs_attr_list_int_ilocked(
462 	struct xfs_attr_list_context	*context)
463 {
464 	struct xfs_inode		*dp = context->dp;
465 
466 	ASSERT(xfs_isilocked(dp, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
467 
468 	/*
469 	 * Decide on what work routines to call based on the inode size.
470 	 */
471 	if (!xfs_inode_hasattr(dp))
472 		return 0;
473 	else if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL)
474 		return xfs_attr_shortform_list(context);
475 	else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK))
476 		return xfs_attr_leaf_list(context);
477 	return xfs_attr_node_list(context);
478 }
479 
480 int
481 xfs_attr_list_int(
482 	xfs_attr_list_context_t *context)
483 {
484 	int error;
485 	xfs_inode_t *dp = context->dp;
486 	uint		lock_mode;
487 
488 	XFS_STATS_INC(dp->i_mount, xs_attr_list);
489 
490 	if (XFS_FORCED_SHUTDOWN(dp->i_mount))
491 		return -EIO;
492 
493 	lock_mode = xfs_ilock_attr_map_shared(dp);
494 	error = xfs_attr_list_int_ilocked(context);
495 	xfs_iunlock(dp, lock_mode);
496 	return error;
497 }
498 
499 #define	ATTR_ENTBASESIZE		/* minimum bytes used by an attr */ \
500 	(((struct attrlist_ent *) 0)->a_name - (char *) 0)
501 #define	ATTR_ENTSIZE(namelen)		/* actual bytes used by an attr */ \
502 	((ATTR_ENTBASESIZE + (namelen) + 1 + sizeof(u_int32_t)-1) \
503 	 & ~(sizeof(u_int32_t)-1))
504 
505 /*
506  * Format an attribute and copy it out to the user's buffer.
507  * Take care to check values and protect against them changing later,
508  * we may be reading them directly out of a user buffer.
509  */
510 STATIC void
511 xfs_attr_put_listent(
512 	xfs_attr_list_context_t *context,
513 	int		flags,
514 	unsigned char	*name,
515 	int		namelen,
516 	int		valuelen)
517 {
518 	struct attrlist *alist = (struct attrlist *)context->alist;
519 	attrlist_ent_t *aep;
520 	int arraytop;
521 
522 	ASSERT(!(context->flags & ATTR_KERNOVAL));
523 	ASSERT(context->count >= 0);
524 	ASSERT(context->count < (ATTR_MAX_VALUELEN/8));
525 	ASSERT(context->firstu >= sizeof(*alist));
526 	ASSERT(context->firstu <= context->bufsize);
527 
528 	/*
529 	 * Only list entries in the right namespace.
530 	 */
531 	if (((context->flags & ATTR_SECURE) == 0) !=
532 	    ((flags & XFS_ATTR_SECURE) == 0))
533 		return;
534 	if (((context->flags & ATTR_ROOT) == 0) !=
535 	    ((flags & XFS_ATTR_ROOT) == 0))
536 		return;
537 
538 	arraytop = sizeof(*alist) +
539 			context->count * sizeof(alist->al_offset[0]);
540 	context->firstu -= ATTR_ENTSIZE(namelen);
541 	if (context->firstu < arraytop) {
542 		trace_xfs_attr_list_full(context);
543 		alist->al_more = 1;
544 		context->seen_enough = 1;
545 		return;
546 	}
547 
548 	aep = (attrlist_ent_t *)&context->alist[context->firstu];
549 	aep->a_valuelen = valuelen;
550 	memcpy(aep->a_name, name, namelen);
551 	aep->a_name[namelen] = 0;
552 	alist->al_offset[context->count++] = context->firstu;
553 	alist->al_count = context->count;
554 	trace_xfs_attr_list_add(context);
555 	return;
556 }
557 
558 /*
559  * Generate a list of extended attribute names and optionally
560  * also value lengths.  Positive return value follows the XFS
561  * convention of being an error, zero or negative return code
562  * is the length of the buffer returned (negated), indicating
563  * success.
564  */
565 int
566 xfs_attr_list(
567 	xfs_inode_t	*dp,
568 	char		*buffer,
569 	int		bufsize,
570 	int		flags,
571 	attrlist_cursor_kern_t *cursor)
572 {
573 	xfs_attr_list_context_t context;
574 	struct attrlist *alist;
575 	int error;
576 
577 	/*
578 	 * Validate the cursor.
579 	 */
580 	if (cursor->pad1 || cursor->pad2)
581 		return -EINVAL;
582 	if ((cursor->initted == 0) &&
583 	    (cursor->hashval || cursor->blkno || cursor->offset))
584 		return -EINVAL;
585 
586 	/*
587 	 * Check for a properly aligned buffer.
588 	 */
589 	if (((long)buffer) & (sizeof(int)-1))
590 		return -EFAULT;
591 	if (flags & ATTR_KERNOVAL)
592 		bufsize = 0;
593 
594 	/*
595 	 * Initialize the output buffer.
596 	 */
597 	memset(&context, 0, sizeof(context));
598 	context.dp = dp;
599 	context.cursor = cursor;
600 	context.resynch = 1;
601 	context.flags = flags;
602 	context.alist = buffer;
603 	context.bufsize = (bufsize & ~(sizeof(int)-1));  /* align */
604 	context.firstu = context.bufsize;
605 	context.put_listent = xfs_attr_put_listent;
606 
607 	alist = (struct attrlist *)context.alist;
608 	alist->al_count = 0;
609 	alist->al_more = 0;
610 	alist->al_offset[0] = context.bufsize;
611 
612 	error = xfs_attr_list_int(&context);
613 	ASSERT(error <= 0);
614 	return error;
615 }
616