xref: /openbmc/linux/fs/xfs/xfs_attr_list.c (revision 5bd8e16d)
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_types.h"
22 #include "xfs_bit.h"
23 #include "xfs_log.h"
24 #include "xfs_trans.h"
25 #include "xfs_sb.h"
26 #include "xfs_ag.h"
27 #include "xfs_mount.h"
28 #include "xfs_da_btree.h"
29 #include "xfs_bmap_btree.h"
30 #include "xfs_alloc_btree.h"
31 #include "xfs_ialloc_btree.h"
32 #include "xfs_alloc.h"
33 #include "xfs_btree.h"
34 #include "xfs_attr_sf.h"
35 #include "xfs_attr_remote.h"
36 #include "xfs_dinode.h"
37 #include "xfs_inode.h"
38 #include "xfs_inode_item.h"
39 #include "xfs_bmap.h"
40 #include "xfs_attr.h"
41 #include "xfs_attr_leaf.h"
42 #include "xfs_error.h"
43 #include "xfs_trace.h"
44 #include "xfs_buf_item.h"
45 #include "xfs_cksum.h"
46 
47 STATIC int
48 xfs_attr_shortform_compare(const void *a, const void *b)
49 {
50 	xfs_attr_sf_sort_t *sa, *sb;
51 
52 	sa = (xfs_attr_sf_sort_t *)a;
53 	sb = (xfs_attr_sf_sort_t *)b;
54 	if (sa->hash < sb->hash) {
55 		return(-1);
56 	} else if (sa->hash > sb->hash) {
57 		return(1);
58 	} else {
59 		return(sa->entno - sb->entno);
60 	}
61 }
62 
63 #define XFS_ISRESET_CURSOR(cursor) \
64 	(!((cursor)->initted) && !((cursor)->hashval) && \
65 	 !((cursor)->blkno) && !((cursor)->offset))
66 /*
67  * Copy out entries of shortform attribute lists for attr_list().
68  * Shortform attribute lists are not stored in hashval sorted order.
69  * If the output buffer is not large enough to hold them all, then we
70  * we have to calculate each entries' hashvalue and sort them before
71  * we can begin returning them to the user.
72  */
73 int
74 xfs_attr_shortform_list(xfs_attr_list_context_t *context)
75 {
76 	attrlist_cursor_kern_t *cursor;
77 	xfs_attr_sf_sort_t *sbuf, *sbp;
78 	xfs_attr_shortform_t *sf;
79 	xfs_attr_sf_entry_t *sfe;
80 	xfs_inode_t *dp;
81 	int sbsize, nsbuf, count, i;
82 	int error;
83 
84 	ASSERT(context != NULL);
85 	dp = context->dp;
86 	ASSERT(dp != NULL);
87 	ASSERT(dp->i_afp != NULL);
88 	sf = (xfs_attr_shortform_t *)dp->i_afp->if_u1.if_data;
89 	ASSERT(sf != NULL);
90 	if (!sf->hdr.count)
91 		return(0);
92 	cursor = context->cursor;
93 	ASSERT(cursor != NULL);
94 
95 	trace_xfs_attr_list_sf(context);
96 
97 	/*
98 	 * If the buffer is large enough and the cursor is at the start,
99 	 * do not bother with sorting since we will return everything in
100 	 * one buffer and another call using the cursor won't need to be
101 	 * made.
102 	 * Note the generous fudge factor of 16 overhead bytes per entry.
103 	 * If bufsize is zero then put_listent must be a search function
104 	 * and can just scan through what we have.
105 	 */
106 	if (context->bufsize == 0 ||
107 	    (XFS_ISRESET_CURSOR(cursor) &&
108              (dp->i_afp->if_bytes + sf->hdr.count * 16) < context->bufsize)) {
109 		for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
110 			error = context->put_listent(context,
111 					   sfe->flags,
112 					   sfe->nameval,
113 					   (int)sfe->namelen,
114 					   (int)sfe->valuelen,
115 					   &sfe->nameval[sfe->namelen]);
116 
117 			/*
118 			 * Either search callback finished early or
119 			 * didn't fit it all in the buffer after all.
120 			 */
121 			if (context->seen_enough)
122 				break;
123 
124 			if (error)
125 				return error;
126 			sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
127 		}
128 		trace_xfs_attr_list_sf_all(context);
129 		return(0);
130 	}
131 
132 	/* do no more for a search callback */
133 	if (context->bufsize == 0)
134 		return 0;
135 
136 	/*
137 	 * It didn't all fit, so we have to sort everything on hashval.
138 	 */
139 	sbsize = sf->hdr.count * sizeof(*sbuf);
140 	sbp = sbuf = kmem_alloc(sbsize, KM_SLEEP | KM_NOFS);
141 
142 	/*
143 	 * Scan the attribute list for the rest of the entries, storing
144 	 * the relevant info from only those that match into a buffer.
145 	 */
146 	nsbuf = 0;
147 	for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
148 		if (unlikely(
149 		    ((char *)sfe < (char *)sf) ||
150 		    ((char *)sfe >= ((char *)sf + dp->i_afp->if_bytes)))) {
151 			XFS_CORRUPTION_ERROR("xfs_attr_shortform_list",
152 					     XFS_ERRLEVEL_LOW,
153 					     context->dp->i_mount, sfe);
154 			kmem_free(sbuf);
155 			return XFS_ERROR(EFSCORRUPTED);
156 		}
157 
158 		sbp->entno = i;
159 		sbp->hash = xfs_da_hashname(sfe->nameval, sfe->namelen);
160 		sbp->name = sfe->nameval;
161 		sbp->namelen = sfe->namelen;
162 		/* These are bytes, and both on-disk, don't endian-flip */
163 		sbp->valuelen = sfe->valuelen;
164 		sbp->flags = sfe->flags;
165 		sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
166 		sbp++;
167 		nsbuf++;
168 	}
169 
170 	/*
171 	 * Sort the entries on hash then entno.
172 	 */
173 	xfs_sort(sbuf, nsbuf, sizeof(*sbuf), xfs_attr_shortform_compare);
174 
175 	/*
176 	 * Re-find our place IN THE SORTED LIST.
177 	 */
178 	count = 0;
179 	cursor->initted = 1;
180 	cursor->blkno = 0;
181 	for (sbp = sbuf, i = 0; i < nsbuf; i++, sbp++) {
182 		if (sbp->hash == cursor->hashval) {
183 			if (cursor->offset == count) {
184 				break;
185 			}
186 			count++;
187 		} else if (sbp->hash > cursor->hashval) {
188 			break;
189 		}
190 	}
191 	if (i == nsbuf) {
192 		kmem_free(sbuf);
193 		return(0);
194 	}
195 
196 	/*
197 	 * Loop putting entries into the user buffer.
198 	 */
199 	for ( ; i < nsbuf; i++, sbp++) {
200 		if (cursor->hashval != sbp->hash) {
201 			cursor->hashval = sbp->hash;
202 			cursor->offset = 0;
203 		}
204 		error = context->put_listent(context,
205 					sbp->flags,
206 					sbp->name,
207 					sbp->namelen,
208 					sbp->valuelen,
209 					&sbp->name[sbp->namelen]);
210 		if (error)
211 			return error;
212 		if (context->seen_enough)
213 			break;
214 		cursor->offset++;
215 	}
216 
217 	kmem_free(sbuf);
218 	return(0);
219 }
220 
221 STATIC int
222 xfs_attr_node_list(xfs_attr_list_context_t *context)
223 {
224 	attrlist_cursor_kern_t *cursor;
225 	xfs_attr_leafblock_t *leaf;
226 	xfs_da_intnode_t *node;
227 	struct xfs_attr3_icleaf_hdr leafhdr;
228 	struct xfs_da3_icnode_hdr nodehdr;
229 	struct xfs_da_node_entry *btree;
230 	int error, i;
231 	struct xfs_buf *bp;
232 
233 	trace_xfs_attr_node_list(context);
234 
235 	cursor = context->cursor;
236 	cursor->initted = 1;
237 
238 	/*
239 	 * Do all sorts of validation on the passed-in cursor structure.
240 	 * If anything is amiss, ignore the cursor and look up the hashval
241 	 * starting from the btree root.
242 	 */
243 	bp = NULL;
244 	if (cursor->blkno > 0) {
245 		error = xfs_da3_node_read(NULL, context->dp, cursor->blkno, -1,
246 					      &bp, XFS_ATTR_FORK);
247 		if ((error != 0) && (error != EFSCORRUPTED))
248 			return(error);
249 		if (bp) {
250 			struct xfs_attr_leaf_entry *entries;
251 
252 			node = bp->b_addr;
253 			switch (be16_to_cpu(node->hdr.info.magic)) {
254 			case XFS_DA_NODE_MAGIC:
255 			case XFS_DA3_NODE_MAGIC:
256 				trace_xfs_attr_list_wrong_blk(context);
257 				xfs_trans_brelse(NULL, bp);
258 				bp = NULL;
259 				break;
260 			case XFS_ATTR_LEAF_MAGIC:
261 			case XFS_ATTR3_LEAF_MAGIC:
262 				leaf = bp->b_addr;
263 				xfs_attr3_leaf_hdr_from_disk(&leafhdr, leaf);
264 				entries = xfs_attr3_leaf_entryp(leaf);
265 				if (cursor->hashval > be32_to_cpu(
266 						entries[leafhdr.count - 1].hashval)) {
267 					trace_xfs_attr_list_wrong_blk(context);
268 					xfs_trans_brelse(NULL, bp);
269 					bp = NULL;
270 				} else if (cursor->hashval <= be32_to_cpu(
271 						entries[0].hashval)) {
272 					trace_xfs_attr_list_wrong_blk(context);
273 					xfs_trans_brelse(NULL, bp);
274 					bp = NULL;
275 				}
276 				break;
277 			default:
278 				trace_xfs_attr_list_wrong_blk(context);
279 				xfs_trans_brelse(NULL, bp);
280 				bp = NULL;
281 			}
282 		}
283 	}
284 
285 	/*
286 	 * We did not find what we expected given the cursor's contents,
287 	 * so we start from the top and work down based on the hash value.
288 	 * Note that start of node block is same as start of leaf block.
289 	 */
290 	if (bp == NULL) {
291 		cursor->blkno = 0;
292 		for (;;) {
293 			__uint16_t magic;
294 
295 			error = xfs_da3_node_read(NULL, context->dp,
296 						      cursor->blkno, -1, &bp,
297 						      XFS_ATTR_FORK);
298 			if (error)
299 				return(error);
300 			node = bp->b_addr;
301 			magic = be16_to_cpu(node->hdr.info.magic);
302 			if (magic == XFS_ATTR_LEAF_MAGIC ||
303 			    magic == XFS_ATTR3_LEAF_MAGIC)
304 				break;
305 			if (magic != XFS_DA_NODE_MAGIC &&
306 			    magic != XFS_DA3_NODE_MAGIC) {
307 				XFS_CORRUPTION_ERROR("xfs_attr_node_list(3)",
308 						     XFS_ERRLEVEL_LOW,
309 						     context->dp->i_mount,
310 						     node);
311 				xfs_trans_brelse(NULL, bp);
312 				return XFS_ERROR(EFSCORRUPTED);
313 			}
314 
315 			xfs_da3_node_hdr_from_disk(&nodehdr, node);
316 			btree = xfs_da3_node_tree_p(node);
317 			for (i = 0; i < nodehdr.count; btree++, i++) {
318 				if (cursor->hashval
319 						<= be32_to_cpu(btree->hashval)) {
320 					cursor->blkno = be32_to_cpu(btree->before);
321 					trace_xfs_attr_list_node_descend(context,
322 									 btree);
323 					break;
324 				}
325 			}
326 			if (i == nodehdr.count) {
327 				xfs_trans_brelse(NULL, bp);
328 				return 0;
329 			}
330 			xfs_trans_brelse(NULL, bp);
331 		}
332 	}
333 	ASSERT(bp != NULL);
334 
335 	/*
336 	 * Roll upward through the blocks, processing each leaf block in
337 	 * order.  As long as there is space in the result buffer, keep
338 	 * adding the information.
339 	 */
340 	for (;;) {
341 		leaf = bp->b_addr;
342 		error = xfs_attr3_leaf_list_int(bp, context);
343 		if (error) {
344 			xfs_trans_brelse(NULL, bp);
345 			return error;
346 		}
347 		xfs_attr3_leaf_hdr_from_disk(&leafhdr, leaf);
348 		if (context->seen_enough || leafhdr.forw == 0)
349 			break;
350 		cursor->blkno = leafhdr.forw;
351 		xfs_trans_brelse(NULL, bp);
352 		error = xfs_attr3_leaf_read(NULL, context->dp, cursor->blkno, -1,
353 					   &bp);
354 		if (error)
355 			return error;
356 	}
357 	xfs_trans_brelse(NULL, bp);
358 	return 0;
359 }
360 
361 /*
362  * Copy out attribute list entries for attr_list(), for leaf attribute lists.
363  */
364 int
365 xfs_attr3_leaf_list_int(
366 	struct xfs_buf			*bp,
367 	struct xfs_attr_list_context	*context)
368 {
369 	struct attrlist_cursor_kern	*cursor;
370 	struct xfs_attr_leafblock	*leaf;
371 	struct xfs_attr3_icleaf_hdr	ichdr;
372 	struct xfs_attr_leaf_entry	*entries;
373 	struct xfs_attr_leaf_entry	*entry;
374 	int				retval;
375 	int				i;
376 
377 	trace_xfs_attr_list_leaf(context);
378 
379 	leaf = bp->b_addr;
380 	xfs_attr3_leaf_hdr_from_disk(&ichdr, leaf);
381 	entries = xfs_attr3_leaf_entryp(leaf);
382 
383 	cursor = context->cursor;
384 	cursor->initted = 1;
385 
386 	/*
387 	 * Re-find our place in the leaf block if this is a new syscall.
388 	 */
389 	if (context->resynch) {
390 		entry = &entries[0];
391 		for (i = 0; i < ichdr.count; entry++, i++) {
392 			if (be32_to_cpu(entry->hashval) == cursor->hashval) {
393 				if (cursor->offset == context->dupcnt) {
394 					context->dupcnt = 0;
395 					break;
396 				}
397 				context->dupcnt++;
398 			} else if (be32_to_cpu(entry->hashval) >
399 					cursor->hashval) {
400 				context->dupcnt = 0;
401 				break;
402 			}
403 		}
404 		if (i == ichdr.count) {
405 			trace_xfs_attr_list_notfound(context);
406 			return 0;
407 		}
408 	} else {
409 		entry = &entries[0];
410 		i = 0;
411 	}
412 	context->resynch = 0;
413 
414 	/*
415 	 * We have found our place, start copying out the new attributes.
416 	 */
417 	retval = 0;
418 	for (; i < ichdr.count; entry++, i++) {
419 		if (be32_to_cpu(entry->hashval) != cursor->hashval) {
420 			cursor->hashval = be32_to_cpu(entry->hashval);
421 			cursor->offset = 0;
422 		}
423 
424 		if (entry->flags & XFS_ATTR_INCOMPLETE)
425 			continue;		/* skip incomplete entries */
426 
427 		if (entry->flags & XFS_ATTR_LOCAL) {
428 			xfs_attr_leaf_name_local_t *name_loc =
429 				xfs_attr3_leaf_name_local(leaf, i);
430 
431 			retval = context->put_listent(context,
432 						entry->flags,
433 						name_loc->nameval,
434 						(int)name_loc->namelen,
435 						be16_to_cpu(name_loc->valuelen),
436 						&name_loc->nameval[name_loc->namelen]);
437 			if (retval)
438 				return retval;
439 		} else {
440 			xfs_attr_leaf_name_remote_t *name_rmt =
441 				xfs_attr3_leaf_name_remote(leaf, i);
442 
443 			int valuelen = be32_to_cpu(name_rmt->valuelen);
444 
445 			if (context->put_value) {
446 				xfs_da_args_t args;
447 
448 				memset((char *)&args, 0, sizeof(args));
449 				args.dp = context->dp;
450 				args.whichfork = XFS_ATTR_FORK;
451 				args.valuelen = valuelen;
452 				args.value = kmem_alloc(valuelen, KM_SLEEP | KM_NOFS);
453 				args.rmtblkno = be32_to_cpu(name_rmt->valueblk);
454 				args.rmtblkcnt = xfs_attr3_rmt_blocks(
455 							args.dp->i_mount, valuelen);
456 				retval = xfs_attr_rmtval_get(&args);
457 				if (retval)
458 					return retval;
459 				retval = context->put_listent(context,
460 						entry->flags,
461 						name_rmt->name,
462 						(int)name_rmt->namelen,
463 						valuelen,
464 						args.value);
465 				kmem_free(args.value);
466 			} else {
467 				retval = context->put_listent(context,
468 						entry->flags,
469 						name_rmt->name,
470 						(int)name_rmt->namelen,
471 						valuelen,
472 						NULL);
473 			}
474 			if (retval)
475 				return retval;
476 		}
477 		if (context->seen_enough)
478 			break;
479 		cursor->offset++;
480 	}
481 	trace_xfs_attr_list_leaf_end(context);
482 	return retval;
483 }
484 
485 /*
486  * Copy out attribute entries for attr_list(), for leaf attribute lists.
487  */
488 STATIC int
489 xfs_attr_leaf_list(xfs_attr_list_context_t *context)
490 {
491 	int error;
492 	struct xfs_buf *bp;
493 
494 	trace_xfs_attr_leaf_list(context);
495 
496 	context->cursor->blkno = 0;
497 	error = xfs_attr3_leaf_read(NULL, context->dp, 0, -1, &bp);
498 	if (error)
499 		return XFS_ERROR(error);
500 
501 	error = xfs_attr3_leaf_list_int(bp, context);
502 	xfs_trans_brelse(NULL, bp);
503 	return XFS_ERROR(error);
504 }
505 
506 int
507 xfs_attr_list_int(
508 	xfs_attr_list_context_t *context)
509 {
510 	int error;
511 	xfs_inode_t *dp = context->dp;
512 
513 	XFS_STATS_INC(xs_attr_list);
514 
515 	if (XFS_FORCED_SHUTDOWN(dp->i_mount))
516 		return EIO;
517 
518 	xfs_ilock(dp, XFS_ILOCK_SHARED);
519 
520 	/*
521 	 * Decide on what work routines to call based on the inode size.
522 	 */
523 	if (!xfs_inode_hasattr(dp)) {
524 		error = 0;
525 	} else if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
526 		error = xfs_attr_shortform_list(context);
527 	} else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
528 		error = xfs_attr_leaf_list(context);
529 	} else {
530 		error = xfs_attr_node_list(context);
531 	}
532 
533 	xfs_iunlock(dp, XFS_ILOCK_SHARED);
534 
535 	return error;
536 }
537 
538 #define	ATTR_ENTBASESIZE		/* minimum bytes used by an attr */ \
539 	(((struct attrlist_ent *) 0)->a_name - (char *) 0)
540 #define	ATTR_ENTSIZE(namelen)		/* actual bytes used by an attr */ \
541 	((ATTR_ENTBASESIZE + (namelen) + 1 + sizeof(u_int32_t)-1) \
542 	 & ~(sizeof(u_int32_t)-1))
543 
544 /*
545  * Format an attribute and copy it out to the user's buffer.
546  * Take care to check values and protect against them changing later,
547  * we may be reading them directly out of a user buffer.
548  */
549 STATIC int
550 xfs_attr_put_listent(
551 	xfs_attr_list_context_t *context,
552 	int		flags,
553 	unsigned char	*name,
554 	int		namelen,
555 	int		valuelen,
556 	unsigned char	*value)
557 {
558 	struct attrlist *alist = (struct attrlist *)context->alist;
559 	attrlist_ent_t *aep;
560 	int arraytop;
561 
562 	ASSERT(!(context->flags & ATTR_KERNOVAL));
563 	ASSERT(context->count >= 0);
564 	ASSERT(context->count < (ATTR_MAX_VALUELEN/8));
565 	ASSERT(context->firstu >= sizeof(*alist));
566 	ASSERT(context->firstu <= context->bufsize);
567 
568 	/*
569 	 * Only list entries in the right namespace.
570 	 */
571 	if (((context->flags & ATTR_SECURE) == 0) !=
572 	    ((flags & XFS_ATTR_SECURE) == 0))
573 		return 0;
574 	if (((context->flags & ATTR_ROOT) == 0) !=
575 	    ((flags & XFS_ATTR_ROOT) == 0))
576 		return 0;
577 
578 	arraytop = sizeof(*alist) +
579 			context->count * sizeof(alist->al_offset[0]);
580 	context->firstu -= ATTR_ENTSIZE(namelen);
581 	if (context->firstu < arraytop) {
582 		trace_xfs_attr_list_full(context);
583 		alist->al_more = 1;
584 		context->seen_enough = 1;
585 		return 1;
586 	}
587 
588 	aep = (attrlist_ent_t *)&context->alist[context->firstu];
589 	aep->a_valuelen = valuelen;
590 	memcpy(aep->a_name, name, namelen);
591 	aep->a_name[namelen] = 0;
592 	alist->al_offset[context->count++] = context->firstu;
593 	alist->al_count = context->count;
594 	trace_xfs_attr_list_add(context);
595 	return 0;
596 }
597 
598 /*
599  * Generate a list of extended attribute names and optionally
600  * also value lengths.  Positive return value follows the XFS
601  * convention of being an error, zero or negative return code
602  * is the length of the buffer returned (negated), indicating
603  * success.
604  */
605 int
606 xfs_attr_list(
607 	xfs_inode_t	*dp,
608 	char		*buffer,
609 	int		bufsize,
610 	int		flags,
611 	attrlist_cursor_kern_t *cursor)
612 {
613 	xfs_attr_list_context_t context;
614 	struct attrlist *alist;
615 	int error;
616 
617 	/*
618 	 * Validate the cursor.
619 	 */
620 	if (cursor->pad1 || cursor->pad2)
621 		return(XFS_ERROR(EINVAL));
622 	if ((cursor->initted == 0) &&
623 	    (cursor->hashval || cursor->blkno || cursor->offset))
624 		return XFS_ERROR(EINVAL);
625 
626 	/*
627 	 * Check for a properly aligned buffer.
628 	 */
629 	if (((long)buffer) & (sizeof(int)-1))
630 		return XFS_ERROR(EFAULT);
631 	if (flags & ATTR_KERNOVAL)
632 		bufsize = 0;
633 
634 	/*
635 	 * Initialize the output buffer.
636 	 */
637 	memset(&context, 0, sizeof(context));
638 	context.dp = dp;
639 	context.cursor = cursor;
640 	context.resynch = 1;
641 	context.flags = flags;
642 	context.alist = buffer;
643 	context.bufsize = (bufsize & ~(sizeof(int)-1));  /* align */
644 	context.firstu = context.bufsize;
645 	context.put_listent = xfs_attr_put_listent;
646 
647 	alist = (struct attrlist *)context.alist;
648 	alist->al_count = 0;
649 	alist->al_more = 0;
650 	alist->al_offset[0] = context.bufsize;
651 
652 	error = xfs_attr_list_int(&context);
653 	ASSERT(error >= 0);
654 	return error;
655 }
656