xref: /titanic_41/usr/src/lib/libuutil/common/uu_avl.c (revision 6f45ec7b0b964c3be967c4880e8867ac1e7763a5)
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 2006 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 			    sizeof (pp->uap_name), pp->uap_name, pp);
124 		}
125 	}
126 	(void) pthread_mutex_lock(&uu_apool_list_lock);
127 	pp->uap_next->uap_prev = pp->uap_prev;
128 	pp->uap_prev->uap_next = pp->uap_next;
129 	(void) pthread_mutex_unlock(&uu_apool_list_lock);
130 	pp->uap_prev = NULL;
131 	pp->uap_next = NULL;
132 	uu_free(pp);
133 }
134 
135 void
136 uu_avl_node_init(void *base, uu_avl_node_t *np, uu_avl_pool_t *pp)
137 {
138 	uintptr_t *na = (uintptr_t *)np;
139 
140 	if (pp->uap_debug) {
141 		uintptr_t offset = (uintptr_t)np - (uintptr_t)base;
142 		if (offset + sizeof (*np) > pp->uap_objsize) {
143 			uu_panic("uu_avl_node_init(%p, %p, %p (\"%s\")): "
144 			    "offset %ld doesn't fit in object (size %ld)\n",
145 			    base, np, pp, pp->uap_name, offset,
146 			    pp->uap_objsize);
147 		}
148 		if (offset != pp->uap_nodeoffset) {
149 			uu_panic("uu_avl_node_init(%p, %p, %p (\"%s\")): "
150 			    "offset %ld doesn't match pool's offset (%ld)\n",
151 			    base, np, pp, pp->uap_name, offset,
152 			    pp->uap_objsize);
153 		}
154 	}
155 
156 	na[0] = POOL_TO_MARKER(pp);
157 	na[1] = 0;
158 }
159 
160 void
161 uu_avl_node_fini(void *base, uu_avl_node_t *np, uu_avl_pool_t *pp)
162 {
163 	uintptr_t *na = (uintptr_t *)np;
164 
165 	if (pp->uap_debug) {
166 		if (na[0] == DEAD_MARKER && na[1] == DEAD_MARKER) {
167 			uu_panic("uu_avl_node_fini(%p, %p, %p (\"%s\")): "
168 			    "node already finied\n",
169 			    base, np, pp, pp->uap_name);
170 		}
171 		if (na[0] != POOL_TO_MARKER(pp) || na[1] != 0) {
172 			uu_panic("uu_avl_node_fini(%p, %p, %p (\"%s\")): "
173 			    "node corrupt, in tree, or in different pool\n",
174 			    base, np, pp, pp->uap_name);
175 		}
176 	}
177 
178 	na[0] = DEAD_MARKER;
179 	na[1] = DEAD_MARKER;
180 	na[2] = DEAD_MARKER;
181 }
182 
183 struct uu_avl_node_compare_info {
184 	uu_compare_fn_t	*ac_compare;
185 	void		*ac_private;
186 	void		*ac_right;
187 	void		*ac_found;
188 };
189 
190 static int
191 uu_avl_node_compare(const void *l, const void *r)
192 {
193 	struct uu_avl_node_compare_info *info =
194 	    (struct uu_avl_node_compare_info *)l;
195 
196 	int res = info->ac_compare(r, info->ac_right, info->ac_private);
197 
198 	if (res == 0) {
199 		if (info->ac_found == NULL)
200 			info->ac_found = (void *)r;
201 		return (-1);
202 	}
203 	if (res < 0)
204 		return (1);
205 	return (-1);
206 }
207 
208 uu_avl_t *
209 uu_avl_create(uu_avl_pool_t *pp, void *parent, uint32_t flags)
210 {
211 	uu_avl_t *ap, *next, *prev;
212 
213 	if (flags & ~UU_AVL_DEBUG) {
214 		uu_set_error(UU_ERROR_UNKNOWN_FLAG);
215 		return (NULL);
216 	}
217 
218 	ap = uu_zalloc(sizeof (*ap));
219 	if (ap == NULL) {
220 		uu_set_error(UU_ERROR_NO_MEMORY);
221 		return (NULL);
222 	}
223 
224 	ap->ua_pool = pp;
225 	ap->ua_parent_enc = UU_PTR_ENCODE(parent);
226 	ap->ua_debug = pp->uap_debug || (flags & UU_AVL_DEBUG);
227 	ap->ua_index = (pp->uap_last_index = INDEX_NEXT(pp->uap_last_index));
228 
229 	avl_create(&ap->ua_tree, &uu_avl_node_compare, pp->uap_objsize,
230 	    pp->uap_nodeoffset);
231 
232 	ap->ua_null_walk.uaw_next = &ap->ua_null_walk;
233 	ap->ua_null_walk.uaw_prev = &ap->ua_null_walk;
234 
235 	(void) pthread_mutex_lock(&pp->uap_lock);
236 	next = &pp->uap_null_avl;
237 	prev = UU_PTR_DECODE(next->ua_prev_enc);
238 	ap->ua_next_enc = UU_PTR_ENCODE(next);
239 	ap->ua_prev_enc = UU_PTR_ENCODE(prev);
240 	next->ua_prev_enc = UU_PTR_ENCODE(ap);
241 	prev->ua_next_enc = UU_PTR_ENCODE(ap);
242 	(void) pthread_mutex_unlock(&pp->uap_lock);
243 
244 	return (ap);
245 }
246 
247 void
248 uu_avl_destroy(uu_avl_t *ap)
249 {
250 	uu_avl_pool_t *pp = ap->ua_pool;
251 
252 	if (ap->ua_debug) {
253 		if (avl_numnodes(&ap->ua_tree) != 0) {
254 			uu_panic("uu_avl_destroy(%p): tree not empty\n", ap);
255 		}
256 		if (ap->ua_null_walk.uaw_next != &ap->ua_null_walk ||
257 		    ap->ua_null_walk.uaw_prev != &ap->ua_null_walk) {
258 			uu_panic("uu_avl_destroy(%p):  outstanding walkers\n",
259 			    ap);
260 		}
261 	}
262 	(void) pthread_mutex_lock(&pp->uap_lock);
263 	UU_AVL_PTR(ap->ua_next_enc)->ua_prev_enc = ap->ua_prev_enc;
264 	UU_AVL_PTR(ap->ua_prev_enc)->ua_next_enc = ap->ua_next_enc;
265 	(void) pthread_mutex_unlock(&pp->uap_lock);
266 	ap->ua_prev_enc = UU_PTR_ENCODE(NULL);
267 	ap->ua_next_enc = UU_PTR_ENCODE(NULL);
268 
269 	ap->ua_pool = NULL;
270 	avl_destroy(&ap->ua_tree);
271 
272 	uu_free(ap);
273 }
274 
275 size_t
276 uu_avl_numnodes(uu_avl_t *ap)
277 {
278 	return (avl_numnodes(&ap->ua_tree));
279 }
280 
281 void *
282 uu_avl_first(uu_avl_t *ap)
283 {
284 	return (avl_first(&ap->ua_tree));
285 }
286 
287 void *
288 uu_avl_last(uu_avl_t *ap)
289 {
290 	return (avl_last(&ap->ua_tree));
291 }
292 
293 void *
294 uu_avl_next(uu_avl_t *ap, void *node)
295 {
296 	return (AVL_NEXT(&ap->ua_tree, node));
297 }
298 
299 void *
300 uu_avl_prev(uu_avl_t *ap, void *node)
301 {
302 	return (AVL_PREV(&ap->ua_tree, node));
303 }
304 
305 static void
306 _avl_walk_init(uu_avl_walk_t *wp, uu_avl_t *ap, uint32_t flags)
307 {
308 	uu_avl_walk_t *next, *prev;
309 
310 	int robust = (flags & UU_WALK_ROBUST);
311 	int direction = (flags & UU_WALK_REVERSE)? -1 : 1;
312 
313 	(void) memset(wp, 0, sizeof (*wp));
314 	wp->uaw_avl = ap;
315 	wp->uaw_robust = robust;
316 	wp->uaw_dir = direction;
317 
318 	if (direction > 0)
319 		wp->uaw_next_result = avl_first(&ap->ua_tree);
320 	else
321 		wp->uaw_next_result = avl_last(&ap->ua_tree);
322 
323 	if (ap->ua_debug || robust) {
324 		wp->uaw_next = next = &ap->ua_null_walk;
325 		wp->uaw_prev = prev = next->uaw_prev;
326 		next->uaw_prev = wp;
327 		prev->uaw_next = wp;
328 	}
329 }
330 
331 static void *
332 _avl_walk_advance(uu_avl_walk_t *wp, uu_avl_t *ap)
333 {
334 	void *np = wp->uaw_next_result;
335 
336 	avl_tree_t *t = &ap->ua_tree;
337 
338 	if (np == NULL)
339 		return (NULL);
340 
341 	wp->uaw_next_result = (wp->uaw_dir > 0)? AVL_NEXT(t, np) :
342 	    AVL_PREV(t, np);
343 
344 	return (np);
345 }
346 
347 static void
348 _avl_walk_fini(uu_avl_walk_t *wp)
349 {
350 	if (wp->uaw_next != NULL) {
351 		wp->uaw_next->uaw_prev = wp->uaw_prev;
352 		wp->uaw_prev->uaw_next = wp->uaw_next;
353 		wp->uaw_next = NULL;
354 		wp->uaw_prev = NULL;
355 	}
356 	wp->uaw_avl = NULL;
357 	wp->uaw_next_result = NULL;
358 }
359 
360 uu_avl_walk_t *
361 uu_avl_walk_start(uu_avl_t *ap, uint32_t flags)
362 {
363 	uu_avl_walk_t *wp;
364 
365 	if (flags & ~(UU_WALK_ROBUST | UU_WALK_REVERSE)) {
366 		uu_set_error(UU_ERROR_UNKNOWN_FLAG);
367 		return (NULL);
368 	}
369 
370 	wp = uu_zalloc(sizeof (*wp));
371 	if (wp == NULL) {
372 		uu_set_error(UU_ERROR_NO_MEMORY);
373 		return (NULL);
374 	}
375 
376 	_avl_walk_init(wp, ap, flags);
377 	return (wp);
378 }
379 
380 void *
381 uu_avl_walk_next(uu_avl_walk_t *wp)
382 {
383 	return (_avl_walk_advance(wp, wp->uaw_avl));
384 }
385 
386 void
387 uu_avl_walk_end(uu_avl_walk_t *wp)
388 {
389 	_avl_walk_fini(wp);
390 	uu_free(wp);
391 }
392 
393 int
394 uu_avl_walk(uu_avl_t *ap, uu_walk_fn_t *func, void *private, uint32_t flags)
395 {
396 	void *e;
397 	uu_avl_walk_t my_walk;
398 
399 	int status = UU_WALK_NEXT;
400 
401 	if (flags & ~(UU_WALK_ROBUST | UU_WALK_REVERSE)) {
402 		uu_set_error(UU_ERROR_UNKNOWN_FLAG);
403 		return (-1);
404 	}
405 
406 	_avl_walk_init(&my_walk, ap, flags);
407 	while (status == UU_WALK_NEXT &&
408 	    (e = _avl_walk_advance(&my_walk, ap)) != NULL)
409 		status = (*func)(e, private);
410 	_avl_walk_fini(&my_walk);
411 
412 	if (status >= 0)
413 		return (0);
414 	uu_set_error(UU_ERROR_CALLBACK_FAILED);
415 	return (-1);
416 }
417 
418 void
419 uu_avl_remove(uu_avl_t *ap, void *elem)
420 {
421 	uu_avl_walk_t *wp;
422 	uu_avl_pool_t *pp = ap->ua_pool;
423 	uintptr_t *na = NODE_ARRAY(pp, elem);
424 
425 	if (ap->ua_debug) {
426 		/*
427 		 * invalidate outstanding uu_avl_index_ts.
428 		 */
429 		ap->ua_index = INDEX_NEXT(ap->ua_index);
430 	}
431 
432 	/*
433 	 * Robust walkers most be advanced, if we are removing the node
434 	 * they are currently using.  In debug mode, non-robust walkers
435 	 * are also on the walker list.
436 	 */
437 	for (wp = ap->ua_null_walk.uaw_next; wp != &ap->ua_null_walk;
438 	    wp = wp->uaw_next) {
439 		if (wp->uaw_robust) {
440 			if (elem == wp->uaw_next_result)
441 				(void) _avl_walk_advance(wp, ap);
442 		} else if (wp->uaw_next_result != NULL) {
443 			uu_panic("uu_avl_remove(%p, %p): active non-robust "
444 			    "walker\n", ap, elem);
445 		}
446 	}
447 
448 	avl_remove(&ap->ua_tree, elem);
449 
450 	na[0] = POOL_TO_MARKER(pp);
451 	na[1] = 0;
452 }
453 
454 void *
455 uu_avl_teardown(uu_avl_t *ap, void **cookie)
456 {
457 	void *elem = avl_destroy_nodes(&ap->ua_tree, cookie);
458 
459 	if (elem != NULL) {
460 		uu_avl_pool_t *pp = ap->ua_pool;
461 		uintptr_t *na = NODE_ARRAY(pp, elem);
462 
463 		na[0] = POOL_TO_MARKER(pp);
464 		na[1] = 0;
465 	}
466 	return (elem);
467 }
468 
469 void *
470 uu_avl_find(uu_avl_t *ap, void *elem, void *private, uu_avl_index_t *out)
471 {
472 	struct uu_avl_node_compare_info info;
473 	void *result;
474 
475 	info.ac_compare = ap->ua_pool->uap_cmp;
476 	info.ac_private = private;
477 	info.ac_right = elem;
478 	info.ac_found = NULL;
479 
480 	result = avl_find(&ap->ua_tree, &info, out);
481 	if (out != NULL)
482 		*out = INDEX_ENCODE(ap, *out);
483 
484 	if (ap->ua_debug && result != NULL)
485 		uu_panic("uu_avl_find: internal error: avl_find succeeded\n");
486 
487 	return (info.ac_found);
488 }
489 
490 void
491 uu_avl_insert(uu_avl_t *ap, void *elem, uu_avl_index_t idx)
492 {
493 	if (ap->ua_debug) {
494 		uu_avl_pool_t *pp = ap->ua_pool;
495 		uintptr_t *na = NODE_ARRAY(pp, elem);
496 
497 		if (na[1] != 0)
498 			uu_panic("uu_avl_insert(%p, %p, %p): node already "
499 			    "in tree, or corrupt\n",
500 			    ap, elem, idx);
501 		if (na[0] == 0)
502 			uu_panic("uu_avl_insert(%p, %p, %p): node not "
503 			    "initialized\n",
504 			    ap, elem, idx);
505 		if (na[0] != POOL_TO_MARKER(pp))
506 			uu_panic("uu_avl_insert(%p, %p, %p): node from "
507 			    "other pool, or corrupt\n",
508 			    ap, elem, idx);
509 
510 		if (!INDEX_VALID(ap, idx))
511 			uu_panic("uu_avl_insert(%p, %p, %p): %s\n",
512 			    ap, elem, idx,
513 			    INDEX_CHECK(idx)? "outdated index" :
514 			    "invalid index");
515 
516 		/*
517 		 * invalidate outstanding uu_avl_index_ts.
518 		 */
519 		ap->ua_index = INDEX_NEXT(ap->ua_index);
520 	}
521 	avl_insert(&ap->ua_tree, elem, INDEX_DECODE(idx));
522 }
523 
524 void *
525 uu_avl_nearest_next(uu_avl_t *ap, uu_avl_index_t idx)
526 {
527 	if (ap->ua_debug && !INDEX_VALID(ap, idx))
528 		uu_panic("uu_avl_nearest_next(%p, %p): %s\n",
529 		    ap, idx, INDEX_CHECK(idx)? "outdated index" :
530 		    "invalid index");
531 	return (avl_nearest(&ap->ua_tree, INDEX_DECODE(idx), AVL_AFTER));
532 }
533 
534 void *
535 uu_avl_nearest_prev(uu_avl_t *ap, uu_avl_index_t idx)
536 {
537 	if (ap->ua_debug && !INDEX_VALID(ap, idx))
538 		uu_panic("uu_avl_nearest_prev(%p, %p): %s\n",
539 		    ap, idx, INDEX_CHECK(idx)? "outdated index" :
540 		    "invalid index");
541 	return (avl_nearest(&ap->ua_tree, INDEX_DECODE(idx), AVL_BEFORE));
542 }
543 
544 /*
545  * called from uu_lockup() and uu_release(), as part of our fork1()-safety.
546  */
547 void
548 uu_avl_lockup(void)
549 {
550 	uu_avl_pool_t *pp;
551 
552 	(void) pthread_mutex_lock(&uu_apool_list_lock);
553 	for (pp = uu_null_apool.uap_next; pp != &uu_null_apool;
554 	    pp = pp->uap_next)
555 		(void) pthread_mutex_lock(&pp->uap_lock);
556 }
557 
558 void
559 uu_avl_release(void)
560 {
561 	uu_avl_pool_t *pp;
562 
563 	for (pp = uu_null_apool.uap_next; pp != &uu_null_apool;
564 	    pp = pp->uap_next)
565 		(void) pthread_mutex_unlock(&pp->uap_lock);
566 	(void) pthread_mutex_unlock(&uu_apool_list_lock);
567 }
568