xref: /illumos-gate/usr/src/lib/libuutil/common/uu_avl.c (revision 4f364e7c95ee7fd9d5bbeddc1940e92405bb0e72)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 #include "libuutil_common.h"
29 
30 #include <stdlib.h>
31 #include <string.h>
32 #include <unistd.h>
33 #include <sys/avl.h>
34 
35 static uu_avl_pool_t	uu_null_apool = { &uu_null_apool, &uu_null_apool };
36 static pthread_mutex_t	uu_apool_list_lock = PTHREAD_MUTEX_INITIALIZER;
37 
38 /*
39  * The index mark change on every insert and delete, to catch stale
40  * references.
41  *
42  * We leave the low bit alone, since the avl code uses it.
43  */
44 #define	INDEX_MAX		(sizeof (uintptr_t) - 2)
45 #define	INDEX_NEXT(m)		(((m) == INDEX_MAX)? 2 : ((m) + 2) & INDEX_MAX)
46 
47 #define	INDEX_DECODE(i)		((i) & ~INDEX_MAX)
48 #define	INDEX_ENCODE(p, n)	(((n) & ~INDEX_MAX) | (p)->ua_index)
49 #define	INDEX_VALID(p, i)	(((i) & INDEX_MAX) == (p)->ua_index)
50 #define	INDEX_CHECK(i)		(((i) & INDEX_MAX) != 0)
51 
52 /*
53  * When an element is inactive (not in a tree), we keep a marked pointer to
54  * its containing pool in its first word, and a NULL pointer in its second.
55  *
56  * On insert, we use these to verify that it comes from the correct pool.
57  */
58 #define	NODE_ARRAY(p, n)	((uintptr_t *)((uintptr_t)(n) + \
59 				    (pp)->uap_nodeoffset))
60 
61 #define	POOL_TO_MARKER(pp) (((uintptr_t)(pp) | 1))
62 
63 #define	DEAD_MARKER		0xc4
64 
65 uu_avl_pool_t *
66 uu_avl_pool_create(const char *name, size_t objsize, size_t nodeoffset,
67     uu_compare_fn_t *compare_func, uint32_t flags)
68 {
69 	uu_avl_pool_t *pp, *next, *prev;
70 
71 	if (name == NULL ||
72 	    uu_check_name(name, UU_NAME_DOMAIN) == -1 ||
73 	    nodeoffset + sizeof (uu_avl_node_t) > objsize ||
74 	    compare_func == NULL) {
75 		uu_set_error(UU_ERROR_INVALID_ARGUMENT);
76 		return (NULL);
77 	}
78 
79 	if (flags & ~UU_AVL_POOL_DEBUG) {
80 		uu_set_error(UU_ERROR_UNKNOWN_FLAG);
81 		return (NULL);
82 	}
83 
84 	pp = uu_zalloc(sizeof (uu_avl_pool_t));
85 	if (pp == NULL) {
86 		uu_set_error(UU_ERROR_NO_MEMORY);
87 		return (NULL);
88 	}
89 
90 	(void) strlcpy(pp->uap_name, name, sizeof (pp->uap_name));
91 	pp->uap_nodeoffset = nodeoffset;
92 	pp->uap_objsize = objsize;
93 	pp->uap_cmp = compare_func;
94 	if (flags & UU_AVL_POOL_DEBUG)
95 		pp->uap_debug = 1;
96 	pp->uap_last_index = 0;
97 
98 	(void) pthread_mutex_init(&pp->uap_lock, NULL);
99 
100 	pp->uap_null_avl.ua_next_enc = UU_PTR_ENCODE(&pp->uap_null_avl);
101 	pp->uap_null_avl.ua_prev_enc = UU_PTR_ENCODE(&pp->uap_null_avl);
102 
103 	(void) pthread_mutex_lock(&uu_apool_list_lock);
104 	pp->uap_next = next = &uu_null_apool;
105 	pp->uap_prev = prev = next->uap_prev;
106 	next->uap_prev = pp;
107 	prev->uap_next = pp;
108 	(void) pthread_mutex_unlock(&uu_apool_list_lock);
109 
110 	return (pp);
111 }
112 
113 void
114 uu_avl_pool_destroy(uu_avl_pool_t *pp)
115 {
116 	if (pp->uap_debug) {
117 		if (pp->uap_null_avl.ua_next_enc !=
118 		    UU_PTR_ENCODE(&pp->uap_null_avl) ||
119 		    pp->uap_null_avl.ua_prev_enc !=
120 		    UU_PTR_ENCODE(&pp->uap_null_avl)) {
121 			uu_panic("uu_avl_pool_destroy: Pool \"%.*s\" (%p) has "
122 			    "outstanding avls, or is corrupt.\n",
123 			    (int)sizeof (pp->uap_name), pp->uap_name,
124 			    (void *)pp);
125 		}
126 	}
127 	(void) pthread_mutex_lock(&uu_apool_list_lock);
128 	pp->uap_next->uap_prev = pp->uap_prev;
129 	pp->uap_prev->uap_next = pp->uap_next;
130 	(void) pthread_mutex_unlock(&uu_apool_list_lock);
131 	pp->uap_prev = NULL;
132 	pp->uap_next = NULL;
133 	uu_free(pp);
134 }
135 
136 void
137 uu_avl_node_init(void *base, uu_avl_node_t *np, uu_avl_pool_t *pp)
138 {
139 	uintptr_t *na = (uintptr_t *)np;
140 
141 	if (pp->uap_debug) {
142 		uintptr_t offset = (uintptr_t)np - (uintptr_t)base;
143 		if (offset + sizeof (*np) > pp->uap_objsize) {
144 			uu_panic("uu_avl_node_init(%p, %p, %p (\"%s\")): "
145 			    "offset %ld doesn't fit in object (size %ld)\n",
146 			    base, (void *)np, (void *)pp, pp->uap_name,
147 			    (long)offset, (long)pp->uap_objsize);
148 		}
149 		if (offset != pp->uap_nodeoffset) {
150 			uu_panic("uu_avl_node_init(%p, %p, %p (\"%s\")): "
151 			    "offset %ld doesn't match pool's offset (%ld)\n",
152 			    base, (void *)np, (void *)pp, pp->uap_name,
153 			    (long)offset, (long)pp->uap_objsize);
154 		}
155 	}
156 
157 	na[0] = POOL_TO_MARKER(pp);
158 	na[1] = 0;
159 }
160 
161 void
162 uu_avl_node_fini(void *base, uu_avl_node_t *np, uu_avl_pool_t *pp)
163 {
164 	uintptr_t *na = (uintptr_t *)np;
165 
166 	if (pp->uap_debug) {
167 		if (na[0] == DEAD_MARKER && na[1] == DEAD_MARKER) {
168 			uu_panic("uu_avl_node_fini(%p, %p, %p (\"%s\")): "
169 			    "node already finied\n",
170 			    base, (void *)np, (void *)pp, pp->uap_name);
171 		}
172 		if (na[0] != POOL_TO_MARKER(pp) || na[1] != 0) {
173 			uu_panic("uu_avl_node_fini(%p, %p, %p (\"%s\")): "
174 			    "node corrupt, in tree, or in different pool\n",
175 			    base, (void *)np, (void *)pp, pp->uap_name);
176 		}
177 	}
178 
179 	na[0] = DEAD_MARKER;
180 	na[1] = DEAD_MARKER;
181 	na[2] = DEAD_MARKER;
182 }
183 
184 struct uu_avl_node_compare_info {
185 	uu_compare_fn_t	*ac_compare;
186 	void		*ac_private;
187 	void		*ac_right;
188 	void		*ac_found;
189 };
190 
191 static int
192 uu_avl_node_compare(const void *l, const void *r)
193 {
194 	struct uu_avl_node_compare_info *info =
195 	    (struct uu_avl_node_compare_info *)l;
196 
197 	int res = info->ac_compare(r, info->ac_right, info->ac_private);
198 
199 	if (res == 0) {
200 		if (info->ac_found == NULL)
201 			info->ac_found = (void *)r;
202 		return (-1);
203 	}
204 	if (res < 0)
205 		return (1);
206 	return (-1);
207 }
208 
209 uu_avl_t *
210 uu_avl_create(uu_avl_pool_t *pp, void *parent, uint32_t flags)
211 {
212 	uu_avl_t *ap, *next, *prev;
213 
214 	if (flags & ~UU_AVL_DEBUG) {
215 		uu_set_error(UU_ERROR_UNKNOWN_FLAG);
216 		return (NULL);
217 	}
218 
219 	ap = uu_zalloc(sizeof (*ap));
220 	if (ap == NULL) {
221 		uu_set_error(UU_ERROR_NO_MEMORY);
222 		return (NULL);
223 	}
224 
225 	ap->ua_pool = pp;
226 	ap->ua_parent_enc = UU_PTR_ENCODE(parent);
227 	ap->ua_debug = pp->uap_debug || (flags & UU_AVL_DEBUG);
228 	ap->ua_index = (pp->uap_last_index = INDEX_NEXT(pp->uap_last_index));
229 
230 	avl_create(&ap->ua_tree, &uu_avl_node_compare, pp->uap_objsize,
231 	    pp->uap_nodeoffset);
232 
233 	ap->ua_null_walk.uaw_next = &ap->ua_null_walk;
234 	ap->ua_null_walk.uaw_prev = &ap->ua_null_walk;
235 
236 	(void) pthread_mutex_lock(&pp->uap_lock);
237 	next = &pp->uap_null_avl;
238 	prev = UU_PTR_DECODE(next->ua_prev_enc);
239 	ap->ua_next_enc = UU_PTR_ENCODE(next);
240 	ap->ua_prev_enc = UU_PTR_ENCODE(prev);
241 	next->ua_prev_enc = UU_PTR_ENCODE(ap);
242 	prev->ua_next_enc = UU_PTR_ENCODE(ap);
243 	(void) pthread_mutex_unlock(&pp->uap_lock);
244 
245 	return (ap);
246 }
247 
248 void
249 uu_avl_destroy(uu_avl_t *ap)
250 {
251 	uu_avl_pool_t *pp = ap->ua_pool;
252 
253 	if (ap->ua_debug) {
254 		if (avl_numnodes(&ap->ua_tree) != 0) {
255 			uu_panic("uu_avl_destroy(%p): tree not empty\n",
256 			    (void *)ap);
257 		}
258 		if (ap->ua_null_walk.uaw_next != &ap->ua_null_walk ||
259 		    ap->ua_null_walk.uaw_prev != &ap->ua_null_walk) {
260 			uu_panic("uu_avl_destroy(%p):  outstanding walkers\n",
261 			    (void *)ap);
262 		}
263 	}
264 	(void) pthread_mutex_lock(&pp->uap_lock);
265 	UU_AVL_PTR(ap->ua_next_enc)->ua_prev_enc = ap->ua_prev_enc;
266 	UU_AVL_PTR(ap->ua_prev_enc)->ua_next_enc = ap->ua_next_enc;
267 	(void) pthread_mutex_unlock(&pp->uap_lock);
268 	ap->ua_prev_enc = UU_PTR_ENCODE(NULL);
269 	ap->ua_next_enc = UU_PTR_ENCODE(NULL);
270 
271 	ap->ua_pool = NULL;
272 	avl_destroy(&ap->ua_tree);
273 
274 	uu_free(ap);
275 }
276 
277 size_t
278 uu_avl_numnodes(uu_avl_t *ap)
279 {
280 	return (avl_numnodes(&ap->ua_tree));
281 }
282 
283 void *
284 uu_avl_first(uu_avl_t *ap)
285 {
286 	return (avl_first(&ap->ua_tree));
287 }
288 
289 void *
290 uu_avl_last(uu_avl_t *ap)
291 {
292 	return (avl_last(&ap->ua_tree));
293 }
294 
295 void *
296 uu_avl_next(uu_avl_t *ap, void *node)
297 {
298 	return (AVL_NEXT(&ap->ua_tree, node));
299 }
300 
301 void *
302 uu_avl_prev(uu_avl_t *ap, void *node)
303 {
304 	return (AVL_PREV(&ap->ua_tree, node));
305 }
306 
307 static void
308 _avl_walk_init(uu_avl_walk_t *wp, uu_avl_t *ap, uint32_t flags)
309 {
310 	uu_avl_walk_t *next, *prev;
311 
312 	int robust = (flags & UU_WALK_ROBUST);
313 	int direction = (flags & UU_WALK_REVERSE)? -1 : 1;
314 
315 	(void) memset(wp, 0, sizeof (*wp));
316 	wp->uaw_avl = ap;
317 	wp->uaw_robust = robust;
318 	wp->uaw_dir = direction;
319 
320 	if (direction > 0)
321 		wp->uaw_next_result = avl_first(&ap->ua_tree);
322 	else
323 		wp->uaw_next_result = avl_last(&ap->ua_tree);
324 
325 	if (ap->ua_debug || robust) {
326 		wp->uaw_next = next = &ap->ua_null_walk;
327 		wp->uaw_prev = prev = next->uaw_prev;
328 		next->uaw_prev = wp;
329 		prev->uaw_next = wp;
330 	}
331 }
332 
333 static void *
334 _avl_walk_advance(uu_avl_walk_t *wp, uu_avl_t *ap)
335 {
336 	void *np = wp->uaw_next_result;
337 
338 	avl_tree_t *t = &ap->ua_tree;
339 
340 	if (np == NULL)
341 		return (NULL);
342 
343 	wp->uaw_next_result = (wp->uaw_dir > 0)? AVL_NEXT(t, np) :
344 	    AVL_PREV(t, np);
345 
346 	return (np);
347 }
348 
349 static void
350 _avl_walk_fini(uu_avl_walk_t *wp)
351 {
352 	if (wp->uaw_next != NULL) {
353 		wp->uaw_next->uaw_prev = wp->uaw_prev;
354 		wp->uaw_prev->uaw_next = wp->uaw_next;
355 		wp->uaw_next = NULL;
356 		wp->uaw_prev = NULL;
357 	}
358 	wp->uaw_avl = NULL;
359 	wp->uaw_next_result = NULL;
360 }
361 
362 uu_avl_walk_t *
363 uu_avl_walk_start(uu_avl_t *ap, uint32_t flags)
364 {
365 	uu_avl_walk_t *wp;
366 
367 	if (flags & ~(UU_WALK_ROBUST | UU_WALK_REVERSE)) {
368 		uu_set_error(UU_ERROR_UNKNOWN_FLAG);
369 		return (NULL);
370 	}
371 
372 	wp = uu_zalloc(sizeof (*wp));
373 	if (wp == NULL) {
374 		uu_set_error(UU_ERROR_NO_MEMORY);
375 		return (NULL);
376 	}
377 
378 	_avl_walk_init(wp, ap, flags);
379 	return (wp);
380 }
381 
382 void *
383 uu_avl_walk_next(uu_avl_walk_t *wp)
384 {
385 	return (_avl_walk_advance(wp, wp->uaw_avl));
386 }
387 
388 void
389 uu_avl_walk_end(uu_avl_walk_t *wp)
390 {
391 	_avl_walk_fini(wp);
392 	uu_free(wp);
393 }
394 
395 int
396 uu_avl_walk(uu_avl_t *ap, uu_walk_fn_t *func, void *private, uint32_t flags)
397 {
398 	void *e;
399 	uu_avl_walk_t my_walk;
400 
401 	int status = UU_WALK_NEXT;
402 
403 	if (flags & ~(UU_WALK_ROBUST | UU_WALK_REVERSE)) {
404 		uu_set_error(UU_ERROR_UNKNOWN_FLAG);
405 		return (-1);
406 	}
407 
408 	_avl_walk_init(&my_walk, ap, flags);
409 	while (status == UU_WALK_NEXT &&
410 	    (e = _avl_walk_advance(&my_walk, ap)) != NULL)
411 		status = (*func)(e, private);
412 	_avl_walk_fini(&my_walk);
413 
414 	if (status >= 0)
415 		return (0);
416 	uu_set_error(UU_ERROR_CALLBACK_FAILED);
417 	return (-1);
418 }
419 
420 void
421 uu_avl_remove(uu_avl_t *ap, void *elem)
422 {
423 	uu_avl_walk_t *wp;
424 	uu_avl_pool_t *pp = ap->ua_pool;
425 	uintptr_t *na = NODE_ARRAY(pp, elem);
426 
427 	if (ap->ua_debug) {
428 		/*
429 		 * invalidate outstanding uu_avl_index_ts.
430 		 */
431 		ap->ua_index = INDEX_NEXT(ap->ua_index);
432 	}
433 
434 	/*
435 	 * Robust walkers most be advanced, if we are removing the node
436 	 * they are currently using.  In debug mode, non-robust walkers
437 	 * are also on the walker list.
438 	 */
439 	for (wp = ap->ua_null_walk.uaw_next; wp != &ap->ua_null_walk;
440 	    wp = wp->uaw_next) {
441 		if (wp->uaw_robust) {
442 			if (elem == wp->uaw_next_result)
443 				(void) _avl_walk_advance(wp, ap);
444 		} else if (wp->uaw_next_result != NULL) {
445 			uu_panic("uu_avl_remove(%p, %p): active non-robust "
446 			    "walker\n", (void *)ap, elem);
447 		}
448 	}
449 
450 	avl_remove(&ap->ua_tree, elem);
451 
452 	na[0] = POOL_TO_MARKER(pp);
453 	na[1] = 0;
454 }
455 
456 void *
457 uu_avl_teardown(uu_avl_t *ap, void **cookie)
458 {
459 	void *elem = avl_destroy_nodes(&ap->ua_tree, cookie);
460 
461 	if (elem != NULL) {
462 		uu_avl_pool_t *pp = ap->ua_pool;
463 		uintptr_t *na = NODE_ARRAY(pp, elem);
464 
465 		na[0] = POOL_TO_MARKER(pp);
466 		na[1] = 0;
467 	}
468 	return (elem);
469 }
470 
471 void *
472 uu_avl_find(uu_avl_t *ap, void *elem, void *private, uu_avl_index_t *out)
473 {
474 	struct uu_avl_node_compare_info info;
475 	void *result;
476 
477 	info.ac_compare = ap->ua_pool->uap_cmp;
478 	info.ac_private = private;
479 	info.ac_right = elem;
480 	info.ac_found = NULL;
481 
482 	result = avl_find(&ap->ua_tree, &info, out);
483 	if (out != NULL)
484 		*out = INDEX_ENCODE(ap, *out);
485 
486 	if (ap->ua_debug && result != NULL)
487 		uu_panic("uu_avl_find: internal error: avl_find succeeded\n");
488 
489 	return (info.ac_found);
490 }
491 
492 void
493 uu_avl_insert(uu_avl_t *ap, void *elem, uu_avl_index_t idx)
494 {
495 	if (ap->ua_debug) {
496 		uu_avl_pool_t *pp = ap->ua_pool;
497 		uintptr_t *na = NODE_ARRAY(pp, elem);
498 
499 		if (na[1] != 0)
500 			uu_panic("uu_avl_insert(%p, %p, %p): node already "
501 			    "in tree, or corrupt\n",
502 			    (void *)ap, elem, (void *)idx);
503 		if (na[0] == 0)
504 			uu_panic("uu_avl_insert(%p, %p, %p): node not "
505 			    "initialized\n",
506 			    (void *)ap, elem, (void *)idx);
507 		if (na[0] != POOL_TO_MARKER(pp))
508 			uu_panic("uu_avl_insert(%p, %p, %p): node from "
509 			    "other pool, or corrupt\n",
510 			    (void *)ap, elem, (void *)idx);
511 
512 		if (!INDEX_VALID(ap, idx))
513 			uu_panic("uu_avl_insert(%p, %p, %p): %s\n",
514 			    (void *)ap, elem, (void *)idx,
515 			    INDEX_CHECK(idx)? "outdated index" :
516 			    "invalid index");
517 
518 		/*
519 		 * invalidate outstanding uu_avl_index_ts.
520 		 */
521 		ap->ua_index = INDEX_NEXT(ap->ua_index);
522 	}
523 	avl_insert(&ap->ua_tree, elem, INDEX_DECODE(idx));
524 }
525 
526 void *
527 uu_avl_nearest_next(uu_avl_t *ap, uu_avl_index_t idx)
528 {
529 	if (ap->ua_debug && !INDEX_VALID(ap, idx))
530 		uu_panic("uu_avl_nearest_next(%p, %p): %s\n",
531 		    (void *)ap, (void *)idx, INDEX_CHECK(idx)?
532 		    "outdated index" : "invalid index");
533 	return (avl_nearest(&ap->ua_tree, INDEX_DECODE(idx), AVL_AFTER));
534 }
535 
536 void *
537 uu_avl_nearest_prev(uu_avl_t *ap, uu_avl_index_t idx)
538 {
539 	if (ap->ua_debug && !INDEX_VALID(ap, idx))
540 		uu_panic("uu_avl_nearest_prev(%p, %p): %s\n",
541 		    (void *)ap, (void *)idx, INDEX_CHECK(idx)?
542 		    "outdated index" : "invalid index");
543 	return (avl_nearest(&ap->ua_tree, INDEX_DECODE(idx), AVL_BEFORE));
544 }
545 
546 /*
547  * called from uu_lockup() and uu_release(), as part of our fork1()-safety.
548  */
549 void
550 uu_avl_lockup(void)
551 {
552 	uu_avl_pool_t *pp;
553 
554 	(void) pthread_mutex_lock(&uu_apool_list_lock);
555 	for (pp = uu_null_apool.uap_next; pp != &uu_null_apool;
556 	    pp = pp->uap_next)
557 		(void) pthread_mutex_lock(&pp->uap_lock);
558 }
559 
560 void
561 uu_avl_release(void)
562 {
563 	uu_avl_pool_t *pp;
564 
565 	for (pp = uu_null_apool.uap_next; pp != &uu_null_apool;
566 	    pp = pp->uap_next)
567 		(void) pthread_mutex_unlock(&pp->uap_lock);
568 	(void) pthread_mutex_unlock(&uu_apool_list_lock);
569 }
570