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      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 	(void) pthread_mutex_destroy(&pp->uap_lock);
    132 	pp->uap_prev = NULL;
    133 	pp->uap_next = NULL;
    134 	uu_free(pp);
    135 }
    136 
    137 void
    138 uu_avl_node_init(void *base, uu_avl_node_t *np, uu_avl_pool_t *pp)
    139 {
    140 	uintptr_t *na = (uintptr_t *)np;
    141 
    142 	if (pp->uap_debug) {
    143 		uintptr_t offset = (uintptr_t)np - (uintptr_t)base;
    144 		if (offset + sizeof (*np) > pp->uap_objsize) {
    145 			uu_panic("uu_avl_node_init(%p, %p, %p (\"%s\")): "
    146 			    "offset %ld doesn't fit in object (size %ld)\n",
    147 			    base, (void *)np, (void *)pp, pp->uap_name,
    148 			    (long)offset, (long)pp->uap_objsize);
    149 		}
    150 		if (offset != pp->uap_nodeoffset) {
    151 			uu_panic("uu_avl_node_init(%p, %p, %p (\"%s\")): "
    152 			    "offset %ld doesn't match pool's offset (%ld)\n",
    153 			    base, (void *)np, (void *)pp, pp->uap_name,
    154 			    (long)offset, (long)pp->uap_objsize);
    155 		}
    156 	}
    157 
    158 	na[0] = POOL_TO_MARKER(pp);
    159 	na[1] = 0;
    160 }
    161 
    162 void
    163 uu_avl_node_fini(void *base, uu_avl_node_t *np, uu_avl_pool_t *pp)
    164 {
    165 	uintptr_t *na = (uintptr_t *)np;
    166 
    167 	if (pp->uap_debug) {
    168 		if (na[0] == DEAD_MARKER && na[1] == DEAD_MARKER) {
    169 			uu_panic("uu_avl_node_fini(%p, %p, %p (\"%s\")): "
    170 			    "node already finied\n",
    171 			    base, (void *)np, (void *)pp, pp->uap_name);
    172 		}
    173 		if (na[0] != POOL_TO_MARKER(pp) || na[1] != 0) {
    174 			uu_panic("uu_avl_node_fini(%p, %p, %p (\"%s\")): "
    175 			    "node corrupt, in tree, or in different pool\n",
    176 			    base, (void *)np, (void *)pp, pp->uap_name);
    177 		}
    178 	}
    179 
    180 	na[0] = DEAD_MARKER;
    181 	na[1] = DEAD_MARKER;
    182 	na[2] = DEAD_MARKER;
    183 }
    184 
    185 struct uu_avl_node_compare_info {
    186 	uu_compare_fn_t	*ac_compare;
    187 	void		*ac_private;
    188 	void		*ac_right;
    189 	void		*ac_found;
    190 };
    191 
    192 static int
    193 uu_avl_node_compare(const void *l, const void *r)
    194 {
    195 	struct uu_avl_node_compare_info *info =
    196 	    (struct uu_avl_node_compare_info *)l;
    197 
    198 	int res = info->ac_compare(r, info->ac_right, info->ac_private);
    199 
    200 	if (res == 0) {
    201 		if (info->ac_found == NULL)
    202 			info->ac_found = (void *)r;
    203 		return (-1);
    204 	}
    205 	if (res < 0)
    206 		return (1);
    207 	return (-1);
    208 }
    209 
    210 uu_avl_t *
    211 uu_avl_create(uu_avl_pool_t *pp, void *parent, uint32_t flags)
    212 {
    213 	uu_avl_t *ap, *next, *prev;
    214 
    215 	if (flags & ~UU_AVL_DEBUG) {
    216 		uu_set_error(UU_ERROR_UNKNOWN_FLAG);
    217 		return (NULL);
    218 	}
    219 
    220 	ap = uu_zalloc(sizeof (*ap));
    221 	if (ap == NULL) {
    222 		uu_set_error(UU_ERROR_NO_MEMORY);
    223 		return (NULL);
    224 	}
    225 
    226 	ap->ua_pool = pp;
    227 	ap->ua_parent_enc = UU_PTR_ENCODE(parent);
    228 	ap->ua_debug = pp->uap_debug || (flags & UU_AVL_DEBUG);
    229 	ap->ua_index = (pp->uap_last_index = INDEX_NEXT(pp->uap_last_index));
    230 
    231 	avl_create(&ap->ua_tree, &uu_avl_node_compare, pp->uap_objsize,
    232 	    pp->uap_nodeoffset);
    233 
    234 	ap->ua_null_walk.uaw_next = &ap->ua_null_walk;
    235 	ap->ua_null_walk.uaw_prev = &ap->ua_null_walk;
    236 
    237 	(void) pthread_mutex_lock(&pp->uap_lock);
    238 	next = &pp->uap_null_avl;
    239 	prev = UU_PTR_DECODE(next->ua_prev_enc);
    240 	ap->ua_next_enc = UU_PTR_ENCODE(next);
    241 	ap->ua_prev_enc = UU_PTR_ENCODE(prev);
    242 	next->ua_prev_enc = UU_PTR_ENCODE(ap);
    243 	prev->ua_next_enc = UU_PTR_ENCODE(ap);
    244 	(void) pthread_mutex_unlock(&pp->uap_lock);
    245 
    246 	return (ap);
    247 }
    248 
    249 void
    250 uu_avl_destroy(uu_avl_t *ap)
    251 {
    252 	uu_avl_pool_t *pp = ap->ua_pool;
    253 
    254 	if (ap->ua_debug) {
    255 		if (avl_numnodes(&ap->ua_tree) != 0) {
    256 			uu_panic("uu_avl_destroy(%p): tree not empty\n",
    257 			    (void *)ap);
    258 		}
    259 		if (ap->ua_null_walk.uaw_next != &ap->ua_null_walk ||
    260 		    ap->ua_null_walk.uaw_prev != &ap->ua_null_walk) {
    261 			uu_panic("uu_avl_destroy(%p):  outstanding walkers\n",
    262 			    (void *)ap);
    263 		}
    264 	}
    265 	(void) pthread_mutex_lock(&pp->uap_lock);
    266 	UU_AVL_PTR(ap->ua_next_enc)->ua_prev_enc = ap->ua_prev_enc;
    267 	UU_AVL_PTR(ap->ua_prev_enc)->ua_next_enc = ap->ua_next_enc;
    268 	(void) pthread_mutex_unlock(&pp->uap_lock);
    269 	ap->ua_prev_enc = UU_PTR_ENCODE(NULL);
    270 	ap->ua_next_enc = UU_PTR_ENCODE(NULL);
    271 
    272 	ap->ua_pool = NULL;
    273 	avl_destroy(&ap->ua_tree);
    274 
    275 	uu_free(ap);
    276 }
    277 
    278 size_t
    279 uu_avl_numnodes(uu_avl_t *ap)
    280 {
    281 	return (avl_numnodes(&ap->ua_tree));
    282 }
    283 
    284 void *
    285 uu_avl_first(uu_avl_t *ap)
    286 {
    287 	return (avl_first(&ap->ua_tree));
    288 }
    289 
    290 void *
    291 uu_avl_last(uu_avl_t *ap)
    292 {
    293 	return (avl_last(&ap->ua_tree));
    294 }
    295 
    296 void *
    297 uu_avl_next(uu_avl_t *ap, void *node)
    298 {
    299 	return (AVL_NEXT(&ap->ua_tree, node));
    300 }
    301 
    302 void *
    303 uu_avl_prev(uu_avl_t *ap, void *node)
    304 {
    305 	return (AVL_PREV(&ap->ua_tree, node));
    306 }
    307 
    308 static void
    309 _avl_walk_init(uu_avl_walk_t *wp, uu_avl_t *ap, uint32_t flags)
    310 {
    311 	uu_avl_walk_t *next, *prev;
    312 
    313 	int robust = (flags & UU_WALK_ROBUST);
    314 	int direction = (flags & UU_WALK_REVERSE)? -1 : 1;
    315 
    316 	(void) memset(wp, 0, sizeof (*wp));
    317 	wp->uaw_avl = ap;
    318 	wp->uaw_robust = robust;
    319 	wp->uaw_dir = direction;
    320 
    321 	if (direction > 0)
    322 		wp->uaw_next_result = avl_first(&ap->ua_tree);
    323 	else
    324 		wp->uaw_next_result = avl_last(&ap->ua_tree);
    325 
    326 	if (ap->ua_debug || robust) {
    327 		wp->uaw_next = next = &ap->ua_null_walk;
    328 		wp->uaw_prev = prev = next->uaw_prev;
    329 		next->uaw_prev = wp;
    330 		prev->uaw_next = wp;
    331 	}
    332 }
    333 
    334 static void *
    335 _avl_walk_advance(uu_avl_walk_t *wp, uu_avl_t *ap)
    336 {
    337 	void *np = wp->uaw_next_result;
    338 
    339 	avl_tree_t *t = &ap->ua_tree;
    340 
    341 	if (np == NULL)
    342 		return (NULL);
    343 
    344 	wp->uaw_next_result = (wp->uaw_dir > 0)? AVL_NEXT(t, np) :
    345 	    AVL_PREV(t, np);
    346 
    347 	return (np);
    348 }
    349 
    350 static void
    351 _avl_walk_fini(uu_avl_walk_t *wp)
    352 {
    353 	if (wp->uaw_next != NULL) {
    354 		wp->uaw_next->uaw_prev = wp->uaw_prev;
    355 		wp->uaw_prev->uaw_next = wp->uaw_next;
    356 		wp->uaw_next = NULL;
    357 		wp->uaw_prev = NULL;
    358 	}
    359 	wp->uaw_avl = NULL;
    360 	wp->uaw_next_result = NULL;
    361 }
    362 
    363 uu_avl_walk_t *
    364 uu_avl_walk_start(uu_avl_t *ap, uint32_t flags)
    365 {
    366 	uu_avl_walk_t *wp;
    367 
    368 	if (flags & ~(UU_WALK_ROBUST | UU_WALK_REVERSE)) {
    369 		uu_set_error(UU_ERROR_UNKNOWN_FLAG);
    370 		return (NULL);
    371 	}
    372 
    373 	wp = uu_zalloc(sizeof (*wp));
    374 	if (wp == NULL) {
    375 		uu_set_error(UU_ERROR_NO_MEMORY);
    376 		return (NULL);
    377 	}
    378 
    379 	_avl_walk_init(wp, ap, flags);
    380 	return (wp);
    381 }
    382 
    383 void *
    384 uu_avl_walk_next(uu_avl_walk_t *wp)
    385 {
    386 	return (_avl_walk_advance(wp, wp->uaw_avl));
    387 }
    388 
    389 void
    390 uu_avl_walk_end(uu_avl_walk_t *wp)
    391 {
    392 	_avl_walk_fini(wp);
    393 	uu_free(wp);
    394 }
    395 
    396 int
    397 uu_avl_walk(uu_avl_t *ap, uu_walk_fn_t *func, void *private, uint32_t flags)
    398 {
    399 	void *e;
    400 	uu_avl_walk_t my_walk;
    401 
    402 	int status = UU_WALK_NEXT;
    403 
    404 	if (flags & ~(UU_WALK_ROBUST | UU_WALK_REVERSE)) {
    405 		uu_set_error(UU_ERROR_UNKNOWN_FLAG);
    406 		return (-1);
    407 	}
    408 
    409 	_avl_walk_init(&my_walk, ap, flags);
    410 	while (status == UU_WALK_NEXT &&
    411 	    (e = _avl_walk_advance(&my_walk, ap)) != NULL)
    412 		status = (*func)(e, private);
    413 	_avl_walk_fini(&my_walk);
    414 
    415 	if (status >= 0)
    416 		return (0);
    417 	uu_set_error(UU_ERROR_CALLBACK_FAILED);
    418 	return (-1);
    419 }
    420 
    421 void
    422 uu_avl_remove(uu_avl_t *ap, void *elem)
    423 {
    424 	uu_avl_walk_t *wp;
    425 	uu_avl_pool_t *pp = ap->ua_pool;
    426 	uintptr_t *na = NODE_ARRAY(pp, elem);
    427 
    428 	if (ap->ua_debug) {
    429 		/*
    430 		 * invalidate outstanding uu_avl_index_ts.
    431 		 */
    432 		ap->ua_index = INDEX_NEXT(ap->ua_index);
    433 	}
    434 
    435 	/*
    436 	 * Robust walkers most be advanced, if we are removing the node
    437 	 * they are currently using.  In debug mode, non-robust walkers
    438 	 * are also on the walker list.
    439 	 */
    440 	for (wp = ap->ua_null_walk.uaw_next; wp != &ap->ua_null_walk;
    441 	    wp = wp->uaw_next) {
    442 		if (wp->uaw_robust) {
    443 			if (elem == wp->uaw_next_result)
    444 				(void) _avl_walk_advance(wp, ap);
    445 		} else if (wp->uaw_next_result != NULL) {
    446 			uu_panic("uu_avl_remove(%p, %p): active non-robust "
    447 			    "walker\n", (void *)ap, elem);
    448 		}
    449 	}
    450 
    451 	avl_remove(&ap->ua_tree, elem);
    452 
    453 	na[0] = POOL_TO_MARKER(pp);
    454 	na[1] = 0;
    455 }
    456 
    457 void *
    458 uu_avl_teardown(uu_avl_t *ap, void **cookie)
    459 {
    460 	void *elem = avl_destroy_nodes(&ap->ua_tree, cookie);
    461 
    462 	if (elem != NULL) {
    463 		uu_avl_pool_t *pp = ap->ua_pool;
    464 		uintptr_t *na = NODE_ARRAY(pp, elem);
    465 
    466 		na[0] = POOL_TO_MARKER(pp);
    467 		na[1] = 0;
    468 	}
    469 	return (elem);
    470 }
    471 
    472 void *
    473 uu_avl_find(uu_avl_t *ap, void *elem, void *private, uu_avl_index_t *out)
    474 {
    475 	struct uu_avl_node_compare_info info;
    476 	void *result;
    477 
    478 	info.ac_compare = ap->ua_pool->uap_cmp;
    479 	info.ac_private = private;
    480 	info.ac_right = elem;
    481 	info.ac_found = NULL;
    482 
    483 	result = avl_find(&ap->ua_tree, &info, out);
    484 	if (out != NULL)
    485 		*out = INDEX_ENCODE(ap, *out);
    486 
    487 	if (ap->ua_debug && result != NULL)
    488 		uu_panic("uu_avl_find: internal error: avl_find succeeded\n");
    489 
    490 	return (info.ac_found);
    491 }
    492 
    493 void
    494 uu_avl_insert(uu_avl_t *ap, void *elem, uu_avl_index_t idx)
    495 {
    496 	if (ap->ua_debug) {
    497 		uu_avl_pool_t *pp = ap->ua_pool;
    498 		uintptr_t *na = NODE_ARRAY(pp, elem);
    499 
    500 		if (na[1] != 0)
    501 			uu_panic("uu_avl_insert(%p, %p, %p): node already "
    502 			    "in tree, or corrupt\n",
    503 			    (void *)ap, elem, (void *)idx);
    504 		if (na[0] == 0)
    505 			uu_panic("uu_avl_insert(%p, %p, %p): node not "
    506 			    "initialized\n",
    507 			    (void *)ap, elem, (void *)idx);
    508 		if (na[0] != POOL_TO_MARKER(pp))
    509 			uu_panic("uu_avl_insert(%p, %p, %p): node from "
    510 			    "other pool, or corrupt\n",
    511 			    (void *)ap, elem, (void *)idx);
    512 
    513 		if (!INDEX_VALID(ap, idx))
    514 			uu_panic("uu_avl_insert(%p, %p, %p): %s\n",
    515 			    (void *)ap, elem, (void *)idx,
    516 			    INDEX_CHECK(idx)? "outdated index" :
    517 			    "invalid index");
    518 
    519 		/*
    520 		 * invalidate outstanding uu_avl_index_ts.
    521 		 */
    522 		ap->ua_index = INDEX_NEXT(ap->ua_index);
    523 	}
    524 	avl_insert(&ap->ua_tree, elem, INDEX_DECODE(idx));
    525 }
    526 
    527 void *
    528 uu_avl_nearest_next(uu_avl_t *ap, uu_avl_index_t idx)
    529 {
    530 	if (ap->ua_debug && !INDEX_VALID(ap, idx))
    531 		uu_panic("uu_avl_nearest_next(%p, %p): %s\n",
    532 		    (void *)ap, (void *)idx, INDEX_CHECK(idx)?
    533 		    "outdated index" : "invalid index");
    534 	return (avl_nearest(&ap->ua_tree, INDEX_DECODE(idx), AVL_AFTER));
    535 }
    536 
    537 void *
    538 uu_avl_nearest_prev(uu_avl_t *ap, uu_avl_index_t idx)
    539 {
    540 	if (ap->ua_debug && !INDEX_VALID(ap, idx))
    541 		uu_panic("uu_avl_nearest_prev(%p, %p): %s\n",
    542 		    (void *)ap, (void *)idx, INDEX_CHECK(idx)?
    543 		    "outdated index" : "invalid index");
    544 	return (avl_nearest(&ap->ua_tree, INDEX_DECODE(idx), AVL_BEFORE));
    545 }
    546 
    547 /*
    548  * called from uu_lockup() and uu_release(), as part of our fork1()-safety.
    549  */
    550 void
    551 uu_avl_lockup(void)
    552 {
    553 	uu_avl_pool_t *pp;
    554 
    555 	(void) pthread_mutex_lock(&uu_apool_list_lock);
    556 	for (pp = uu_null_apool.uap_next; pp != &uu_null_apool;
    557 	    pp = pp->uap_next)
    558 		(void) pthread_mutex_lock(&pp->uap_lock);
    559 }
    560 
    561 void
    562 uu_avl_release(void)
    563 {
    564 	uu_avl_pool_t *pp;
    565 
    566 	for (pp = uu_null_apool.uap_next; pp != &uu_null_apool;
    567 	    pp = pp->uap_next)
    568 		(void) pthread_mutex_unlock(&pp->uap_lock);
    569 	(void) pthread_mutex_unlock(&uu_apool_list_lock);
    570 }
    571 
    572 __dso_hidden
    573 void
    574 uu_avl_release_child(void)
    575 {
    576 	uu_avl_pool_t *pp;
    577 
    578 	for (pp = uu_null_apool.uap_next; pp != &uu_null_apool;
    579 	    pp = pp->uap_next)
    580 		(void) pthread_mutex_init(&pp->uap_lock, NULL);
    581 	(void) pthread_mutex_init(&uu_apool_list_lock, NULL);
    582 }
    583