git.sur5r.net Git - openldap/blob - libraries/libldap_r/tpool.c

   1 /* $OpenLDAP$ */
   2 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
   3  *
   4  * Copyright 1998-2005 The OpenLDAP Foundation.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted only as authorized by the OpenLDAP
   9  * Public License.
  10  *
  11  * A copy of this license is available in file LICENSE in the
  12  * top-level directory of the distribution or, alternatively, at
  13  * <http://www.OpenLDAP.org/license.html>.
  14  */
  15
  16 #include "portable.h"
  17
  18 #include <stdio.h>
  19
  20 #include <ac/stdarg.h>
  21 #include <ac/stdlib.h>
  22 #include <ac/string.h>
  23 #include <ac/time.h>
  24 #include <ac/errno.h>
  25
  26 #include "ldap-int.h"
  27 #include "ldap_pvt_thread.h"
  28 #include "ldap_queue.h"
  29
  30 #ifndef LDAP_THREAD_HAVE_TPOOL
  31
  32 enum ldap_int_thread_pool_state {
  33         LDAP_INT_THREAD_POOL_RUNNING,
  34         LDAP_INT_THREAD_POOL_FINISHING,
  35         LDAP_INT_THREAD_POOL_STOPPING,
  36         LDAP_INT_THREAD_POOL_PAUSING
  37 };
  38
  39 typedef struct ldap_int_thread_key_s {
  40         void *ltk_key;
  41         void *ltk_data;
  42         ldap_pvt_thread_pool_keyfree_t *ltk_free;
  43 } ldap_int_thread_key_t;
  44
  45 /* Max number of thread-specific keys we store per thread.
  46  * We don't expect to use many...
  47  */
  48 #define MAXKEYS 32
  49 #define LDAP_MAXTHR     1024    /* must be a power of 2 */
  50
  51 static ldap_pvt_thread_t tid_zero;
  52
  53 #ifdef HAVE_PTHREADS
  54 #define TID_EQ(a,b)     pthread_equal((a),(b))
  55 #else
  56 #define TID_EQ(a,b)     ((a) == (b))
  57 #endif
  58 static struct {
  59         ldap_pvt_thread_t id;
  60         ldap_int_thread_key_t *ctx;
  61 } thread_keys[LDAP_MAXTHR];
  62
  63
  64 typedef struct ldap_int_thread_ctx_s {
  65         union {
  66         LDAP_STAILQ_ENTRY(ldap_int_thread_ctx_s) q;
  67         LDAP_SLIST_ENTRY(ldap_int_thread_ctx_s) l;
  68         LDAP_SLIST_ENTRY(ldap_int_thread_ctx_s) al;
  69         } ltc_next;
  70         ldap_pvt_thread_start_t *ltc_start_routine;
  71         void *ltc_arg;
  72 } ldap_int_thread_ctx_t;
  73
  74 struct ldap_int_thread_pool_s {
  75         LDAP_STAILQ_ENTRY(ldap_int_thread_pool_s) ltp_next;
  76         ldap_pvt_thread_mutex_t ltp_mutex;
  77         ldap_pvt_thread_cond_t ltp_cond;
  78         ldap_pvt_thread_cond_t ltp_pcond;
  79         LDAP_STAILQ_HEAD(tcq, ldap_int_thread_ctx_s) ltp_pending_list;
  80         LDAP_SLIST_HEAD(tcl, ldap_int_thread_ctx_s) ltp_free_list;
  81         LDAP_SLIST_HEAD(tclq, ldap_int_thread_ctx_s) ltp_active_list;
  82         long ltp_state;
  83         long ltp_max_count;
  84         long ltp_max_pending;
  85         long ltp_pending_count;
  86         long ltp_active_count;
  87         long ltp_open_count;
  88         long ltp_starting;
  89 };
  90
  91 static LDAP_STAILQ_HEAD(tpq, ldap_int_thread_pool_s)
  92         ldap_int_thread_pool_list =
  93         LDAP_STAILQ_HEAD_INITIALIZER(ldap_int_thread_pool_list);
  94
  95 static ldap_pvt_thread_mutex_t ldap_pvt_thread_pool_mutex;
  96
  97 static void *ldap_int_thread_pool_wrapper( void *pool );
  98
  99 int
 100 ldap_int_thread_pool_startup ( void )
 101 {
 102         return ldap_pvt_thread_mutex_init(&ldap_pvt_thread_pool_mutex);
 103 }
 104
 105 int
 106 ldap_int_thread_pool_shutdown ( void )
 107 {
 108         struct ldap_int_thread_pool_s *pool;
 109
 110         while ((pool = LDAP_STAILQ_FIRST(&ldap_int_thread_pool_list)) != NULL) {
 111                 LDAP_STAILQ_REMOVE_HEAD(&ldap_int_thread_pool_list, ltp_next);
 112                 ldap_pvt_thread_pool_destroy( &pool, 0);
 113         }
 114         ldap_pvt_thread_mutex_destroy(&ldap_pvt_thread_pool_mutex);
 115         return(0);
 116 }
 117
 118 int
 119 ldap_pvt_thread_pool_init (
 120         ldap_pvt_thread_pool_t *tpool,
 121         int max_threads,
 122         int max_pending )
 123 {
 124         ldap_pvt_thread_pool_t pool;
 125         int rc;
 126
 127         *tpool = NULL;
 128         pool = (ldap_pvt_thread_pool_t) LDAP_CALLOC(1,
 129                 sizeof(struct ldap_int_thread_pool_s));
 130
 131         if (pool == NULL) return(-1);
 132
 133         rc = ldap_pvt_thread_mutex_init(&pool->ltp_mutex);
 134         if (rc != 0)
 135                 return(rc);
 136         rc = ldap_pvt_thread_cond_init(&pool->ltp_cond);
 137         if (rc != 0)
 138                 return(rc);
 139         rc = ldap_pvt_thread_cond_init(&pool->ltp_pcond);
 140         if (rc != 0)
 141                 return(rc);
 142         pool->ltp_state = LDAP_INT_THREAD_POOL_RUNNING;
 143         pool->ltp_max_count = max_threads;
 144         pool->ltp_max_pending = max_pending;
 145         LDAP_STAILQ_INIT(&pool->ltp_pending_list);
 146         LDAP_SLIST_INIT(&pool->ltp_free_list);
 147         LDAP_SLIST_INIT(&pool->ltp_active_list);
 148         ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
 149         LDAP_STAILQ_INSERT_TAIL(&ldap_int_thread_pool_list, pool, ltp_next);
 150         ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
 151
 152 #if 0
 153         /* THIS WILL NOT WORK on some systems.  If the process
 154          * forks after starting a thread, there is no guarantee
 155          * that the thread will survive the fork.  For example,
 156          * slapd forks in order to daemonize, and does so after
 157          * calling ldap_pvt_thread_pool_init.  On some systems,
 158          * this initial thread does not run in the child process,
 159          * but ltp_open_count == 1, so two things happen:
 160          * 1) the first client connection fails, and 2) when
 161          * slapd is kill'ed, it never terminates since it waits
 162          * for all worker threads to exit. */
 163
 164         /* start up one thread, just so there is one. no need to
 165          * lock the mutex right now, since no threads are running.
 166          */
 167         pool->ltp_open_count++;
 168
 169         ldap_pvt_thread_t thr;
 170         rc = ldap_pvt_thread_create( &thr, 1, ldap_int_thread_pool_wrapper, pool );
 171
 172         if( rc != 0) {
 173                 /* couldn't start one?  then don't start any */
 174                 ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
 175                 LDAP_STAILQ_REMOVE(ldap_int_thread_pool_list, pool,
 176                         ldap_int_thread_pool_s, ltp_next);
 177                 ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
 178                 ldap_pvt_thread_cond_destroy(&pool->ltp_pcond);
 179                 ldap_pvt_thread_cond_destroy(&pool->ltp_cond);
 180                 ldap_pvt_thread_mutex_destroy(&pool->ltp_mutex);
 181                 LDAP_FREE(pool);
 182                 return(-1);
 183         }
 184 #endif
 185
 186         *tpool = pool;
 187         return(0);
 188 }
 189
 190 #define TID_HASH(tid, hash) do { int i; \
 191         unsigned char *ptr = (unsigned char *)&(tid); \
 192         for (i=0, hash=0; i<sizeof(tid); i++) hash += ptr[i]; } while(0)
 193
 194 int
 195 ldap_pvt_thread_pool_submit (
 196         ldap_pvt_thread_pool_t *tpool,
 197         ldap_pvt_thread_start_t *start_routine, void *arg )
 198 {
 199         struct ldap_int_thread_pool_s *pool;
 200         ldap_int_thread_ctx_t *ctx;
 201         int need_thread = 0;
 202         ldap_pvt_thread_t thr;
 203
 204         if (tpool == NULL)
 205                 return(-1);
 206
 207         pool = *tpool;
 208
 209         if (pool == NULL)
 210                 return(-1);
 211
 212         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 213         if ((pool->ltp_state != LDAP_INT_THREAD_POOL_RUNNING &&
 214                 pool->ltp_state != LDAP_INT_THREAD_POOL_PAUSING)
 215                 || (pool->ltp_max_pending > 0
 216                         && pool->ltp_pending_count >= pool->ltp_max_pending))
 217         {
 218                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 219                 return(-1);
 220         }
 221         ctx = LDAP_SLIST_FIRST(&pool->ltp_free_list);
 222         if (ctx) {
 223                 LDAP_SLIST_REMOVE_HEAD(&pool->ltp_free_list, ltc_next.l);
 224         } else {
 225                 ctx = (ldap_int_thread_ctx_t *) LDAP_MALLOC(
 226                         sizeof(ldap_int_thread_ctx_t));
 227                 if (ctx == NULL) {
 228                         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 229                         return(-1);
 230                 }
 231         }
 232
 233         ctx->ltc_start_routine = start_routine;
 234         ctx->ltc_arg = arg;
 235
 236         pool->ltp_pending_count++;
 237         LDAP_STAILQ_INSERT_TAIL(&pool->ltp_pending_list, ctx, ltc_next.q);
 238         if (pool->ltp_state == LDAP_INT_THREAD_POOL_PAUSING) {
 239                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 240                 return(0);
 241         }
 242         ldap_pvt_thread_cond_signal(&pool->ltp_cond);
 243         if ((pool->ltp_open_count <= 0
 244 #if 0
 245                         || pool->ltp_pending_count > 1
 246 #endif
 247                         || pool->ltp_open_count == pool->ltp_active_count)
 248                 && (pool->ltp_max_count <= 0
 249                         || pool->ltp_open_count < pool->ltp_max_count))
 250         {
 251                 pool->ltp_open_count++;
 252                 pool->ltp_starting++;
 253                 need_thread = 1;
 254         }
 255         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 256
 257         if (need_thread) {
 258                 int rc;
 259
 260                 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 261
 262                 rc = ldap_pvt_thread_create( &thr, 1,
 263                         ldap_int_thread_pool_wrapper, pool );
 264                 if (rc == 0) {
 265                         int hash;
 266                         pool->ltp_starting--;
 267
 268                         /* assign this thread ID to a key slot; start
 269                          * at the thread ID itself (mod LDAP_MAXTHR) and
 270                          * look for an empty slot.
 271                          */
 272                         TID_HASH(thr, hash);
 273                         for (rc = hash & (LDAP_MAXTHR-1);
 274                                 !TID_EQ(thread_keys[rc].id, tid_zero);
 275                                 rc = (rc+1) & (LDAP_MAXTHR-1));
 276                         thread_keys[rc].id = thr;
 277                 } else {
 278                         /* couldn't create thread.  back out of
 279                          * ltp_open_count and check for even worse things.
 280                          */
 281                         pool->ltp_open_count--;
 282                         pool->ltp_starting--;
 283                         if (pool->ltp_open_count == 0) {
 284                                 /* no open threads at all?!?
 285                                  */
 286                                 ldap_int_thread_ctx_t *ptr;
 287                                 LDAP_STAILQ_FOREACH(ptr, &pool->ltp_pending_list, ltc_next.q)
 288                                         if (ptr == ctx) break;
 289                                 if (ptr == ctx) {
 290                                         /* no open threads, context not handled, so
 291                                          * back out of ltp_pending_count, free the context,
 292                                          * report the error.
 293                                          */
 294                                         LDAP_STAILQ_REMOVE(&pool->ltp_pending_list, ctx,
 295                                                 ldap_int_thread_ctx_s, ltc_next.q);
 296                                         pool->ltp_pending_count++;
 297                                         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 298                                         LDAP_FREE(ctx);
 299                                         return(-1);
 300                                 }
 301                         }
 302                         /* there is another open thread, so this
 303                          * context will be handled eventually.
 304                          * continue on and signal that the context
 305                          * is waiting.
 306                          */
 307                 }
 308                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 309         }
 310
 311         return(0);
 312 }
 313
 314 int
 315 ldap_pvt_thread_pool_maxthreads ( ldap_pvt_thread_pool_t *tpool, int max_threads )
 316 {
 317         struct ldap_int_thread_pool_s *pool;
 318
 319         if (tpool == NULL)
 320                 return(-1);
 321
 322         pool = *tpool;
 323
 324         if (pool == NULL)
 325                 return(-1);
 326
 327         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 328         pool->ltp_max_count = max_threads;
 329         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 330         return(0);
 331 }
 332
 333 int
 334 ldap_pvt_thread_pool_backload ( ldap_pvt_thread_pool_t *tpool )
 335 {
 336         struct ldap_int_thread_pool_s *pool;
 337         int count;
 338
 339         if (tpool == NULL)
 340                 return(-1);
 341
 342         pool = *tpool;
 343
 344         if (pool == NULL)
 345                 return(0);
 346
 347         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 348         count = pool->ltp_pending_count + pool->ltp_active_count;
 349         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 350         return(count);
 351 }
 352
 353 int
 354 ldap_pvt_thread_pool_destroy ( ldap_pvt_thread_pool_t *tpool, int run_pending )
 355 {
 356         struct ldap_int_thread_pool_s *pool, *pptr;
 357         long waiting;
 358         ldap_int_thread_ctx_t *ctx;
 359
 360         if (tpool == NULL)
 361                 return(-1);
 362
 363         pool = *tpool;
 364
 365         if (pool == NULL) return(-1);
 366
 367         ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
 368         LDAP_STAILQ_FOREACH(pptr, &ldap_int_thread_pool_list, ltp_next)
 369                 if (pptr == pool) break;
 370         if (pptr == pool)
 371                 LDAP_STAILQ_REMOVE(&ldap_int_thread_pool_list, pool,
 372                         ldap_int_thread_pool_s, ltp_next);
 373         ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
 374
 375         if (pool != pptr) return(-1);
 376
 377         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 378         pool->ltp_state = run_pending
 379                 ? LDAP_INT_THREAD_POOL_FINISHING
 380                 : LDAP_INT_THREAD_POOL_STOPPING;
 381
 382         ldap_pvt_thread_cond_broadcast(&pool->ltp_cond);
 383         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 384
 385         do {
 386                 ldap_pvt_thread_yield();
 387                 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 388                 waiting = pool->ltp_open_count;
 389                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 390         } while (waiting > 0);
 391
 392         while ((ctx = LDAP_STAILQ_FIRST(&pool->ltp_pending_list)) != NULL)
 393         {
 394                 LDAP_STAILQ_REMOVE_HEAD(&pool->ltp_pending_list, ltc_next.q);
 395                 LDAP_FREE(ctx);
 396         }
 397
 398         while ((ctx = LDAP_SLIST_FIRST(&pool->ltp_free_list)) != NULL)
 399         {
 400                 LDAP_SLIST_REMOVE_HEAD(&pool->ltp_free_list, ltc_next.l);
 401                 LDAP_FREE(ctx);
 402         }
 403
 404         ldap_pvt_thread_cond_destroy(&pool->ltp_pcond);
 405         ldap_pvt_thread_cond_destroy(&pool->ltp_cond);
 406         ldap_pvt_thread_mutex_destroy(&pool->ltp_mutex);
 407         LDAP_FREE(pool);
 408         return(0);
 409 }
 410
 411 static void *
 412 ldap_int_thread_pool_wrapper (
 413         void *xpool )
 414 {
 415         struct ldap_int_thread_pool_s *pool = xpool;
 416         ldap_int_thread_ctx_t *ctx;
 417         ldap_int_thread_key_t ltc_key[MAXKEYS];
 418         ldap_pvt_thread_t tid;
 419         int i, keyslot, hash;
 420
 421         if (pool == NULL)
 422                 return NULL;
 423
 424         for ( i=0; i<MAXKEYS; i++ ) {
 425                 ltc_key[i].ltk_key = NULL;
 426         }
 427
 428         tid = ldap_pvt_thread_self();
 429
 430         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 431
 432         /* store pointer to our keys */
 433         TID_HASH(tid, hash);
 434         for (i = hash & (LDAP_MAXTHR-1); !TID_EQ(thread_keys[i].id, tid);
 435                                 i = (i+1) & (LDAP_MAXTHR-1));
 436         thread_keys[i].ctx = ltc_key;
 437         keyslot = i;
 438
 439         while (pool->ltp_state != LDAP_INT_THREAD_POOL_STOPPING) {
 440                 ctx = LDAP_STAILQ_FIRST(&pool->ltp_pending_list);
 441                 if (ctx) {
 442                         LDAP_STAILQ_REMOVE_HEAD(&pool->ltp_pending_list, ltc_next.q);
 443                 } else {
 444                         if (pool->ltp_state == LDAP_INT_THREAD_POOL_FINISHING)
 445                                 break;
 446                         if (pool->ltp_max_count > 0
 447                                 && pool->ltp_open_count > pool->ltp_max_count)
 448                         {
 449                                 /* too many threads running (can happen if the
 450                                  * maximum threads value is set during ongoing
 451                                  * operation using ldap_pvt_thread_pool_maxthreads)
 452                                  * so let this thread die.
 453                                  */
 454                                 break;
 455                         }
 456
 457                         /* we could check an idle timer here, and let the
 458                          * thread die if it has been inactive for a while.
 459                          * only die if there are other open threads (i.e.,
 460                          * always have at least one thread open).  the check
 461                          * should be like this:
 462                          *   if (pool->ltp_open_count > 1 && pool->ltp_starting == 0)
 463                          *       check timer, leave thread (break;)
 464                          */
 465
 466                         if (pool->ltp_state == LDAP_INT_THREAD_POOL_RUNNING)
 467                                 ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
 468
 469                         continue;
 470                 }
 471
 472                 pool->ltp_pending_count--;
 473
 474                 LDAP_SLIST_INSERT_HEAD(&pool->ltp_active_list, ctx, ltc_next.al);
 475                 pool->ltp_active_count++;
 476                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 477
 478                 ctx->ltc_start_routine(ltc_key, ctx->ltc_arg);
 479
 480                 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 481                 LDAP_SLIST_REMOVE(&pool->ltp_active_list, ctx,
 482                         ldap_int_thread_ctx_s, ltc_next.al);
 483                 LDAP_SLIST_INSERT_HEAD(&pool->ltp_free_list, ctx, ltc_next.l);
 484                 pool->ltp_active_count--;
 485
 486                 if (pool->ltp_state == LDAP_INT_THREAD_POOL_PAUSING) {
 487                         if (pool->ltp_active_count < 2) {
 488                                 ldap_pvt_thread_cond_signal(&pool->ltp_pcond);
 489                         }
 490                         ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
 491                 }
 492                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 493
 494                 ldap_pvt_thread_yield();
 495
 496                 /* if we use an idle timer, here's
 497                  * a good place to update it
 498                  */
 499
 500                 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 501         }
 502
 503         for ( i=0; i<MAXKEYS && ltc_key[i].ltk_key; i++ ) {
 504                 if (ltc_key[i].ltk_free)
 505                         ltc_key[i].ltk_free(
 506                                 ltc_key[i].ltk_key,
 507                                 ltc_key[i].ltk_data );
 508         }
 509
 510         thread_keys[keyslot].ctx = NULL;
 511         thread_keys[keyslot].id = tid_zero;
 512
 513         pool->ltp_open_count--;
 514         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 515
 516         ldap_pvt_thread_exit(NULL);
 517         return(NULL);
 518 }
 519
 520 int
 521 ldap_pvt_thread_pool_pause (
 522         ldap_pvt_thread_pool_t *tpool )
 523 {
 524         struct ldap_int_thread_pool_s *pool;
 525
 526         if (tpool == NULL)
 527                 return(-1);
 528
 529         pool = *tpool;
 530
 531         if (pool == NULL)
 532                 return(0);
 533
 534         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 535
 536         /* If someone else has already requested a pause, we have to wait */
 537         if (pool->ltp_state == LDAP_INT_THREAD_POOL_PAUSING) {
 538                 pool->ltp_pending_count++;
 539                 pool->ltp_active_count--;
 540                 ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
 541                 pool->ltp_pending_count--;
 542                 pool->ltp_active_count++;
 543         }
 544         /* Wait for everyone else to finish */
 545         pool->ltp_state = LDAP_INT_THREAD_POOL_PAUSING;
 546         while (pool->ltp_active_count > 1) {
 547                 ldap_pvt_thread_cond_wait(&pool->ltp_pcond, &pool->ltp_mutex);
 548         }
 549         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 550         return(0);
 551 }
 552
 553 int
 554 ldap_pvt_thread_pool_resume (
 555         ldap_pvt_thread_pool_t *tpool )
 556 {
 557         struct ldap_int_thread_pool_s *pool;
 558
 559         if (tpool == NULL)
 560                 return(-1);
 561
 562         pool = *tpool;
 563
 564         if (pool == NULL)
 565                 return(0);
 566
 567         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 568
 569         pool->ltp_state = LDAP_INT_THREAD_POOL_RUNNING;
 570         ldap_pvt_thread_cond_broadcast(&pool->ltp_cond);
 571         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 572         return(0);
 573 }
 574
 575 int ldap_pvt_thread_pool_getkey(
 576         void *xctx,
 577         void *key,
 578         void **data,
 579         ldap_pvt_thread_pool_keyfree_t **kfree )
 580 {
 581         ldap_int_thread_key_t *ctx = xctx;
 582         int i;
 583
 584         if ( !ctx || !data ) return EINVAL;
 585
 586         for ( i=0; i<MAXKEYS && ctx[i].ltk_key; i++ ) {
 587                 if ( ctx[i].ltk_key == key ) {
 588                         *data = ctx[i].ltk_data;
 589                         if ( kfree ) *kfree = ctx[i].ltk_free;
 590                         return 0;
 591                 }
 592         }
 593         return ENOENT;
 594 }
 595
 596 int ldap_pvt_thread_pool_setkey(
 597         void *xctx,
 598         void *key,
 599         void *data,
 600         ldap_pvt_thread_pool_keyfree_t *kfree )
 601 {
 602         ldap_int_thread_key_t *ctx = xctx;
 603         int i;
 604
 605         if ( !ctx || !key ) return EINVAL;
 606
 607         for ( i=0; i<MAXKEYS; i++ ) {
 608                 if ( !ctx[i].ltk_key || ctx[i].ltk_key == key ) {
 609                         ctx[i].ltk_key = key;
 610                         ctx[i].ltk_data = data;
 611                         ctx[i].ltk_free = kfree;
 612                         return 0;
 613                 }
 614         }
 615         return ENOMEM;
 616 }
 617
 618 /* Free all elements with this key, no matter which thread they're in.
 619  * May only be called while the pool is paused.
 620  */
 621 void ldap_pvt_thread_pool_purgekey( void *key )
 622 {
 623         int i, j;
 624         ldap_int_thread_key_t *ctx;
 625
 626         for ( i=0; i<LDAP_MAXTHR; i++ ) {
 627                 if ( thread_keys[i].ctx ) {
 628                         ctx = thread_keys[i].ctx;
 629                         for ( j=0; j<MAXKEYS; j++ ) {
 630                                 if ( ctx[j].ltk_key == key ) {
 631                                         if (ctx[j].ltk_free)
 632                                                 ctx[j].ltk_free( ctx[j].ltk_key, ctx[j].ltk_data );
 633                                         ctx[j].ltk_key = NULL;
 634                                         ctx[j].ltk_free = NULL;
 635                                         break;
 636                                 }
 637                         }
 638                 }
 639         }
 640 }
 641
 642 /*
 643  * This is necessary if the caller does not have access to the
 644  * thread context handle (for example, a slapd plugin calling
 645  * slapi_search_internal()). No doubt it is more efficient to
 646  * for the application to keep track of the thread context
 647  * handles itself.
 648  */
 649 void *ldap_pvt_thread_pool_context( )
 650 {
 651         ldap_pvt_thread_t tid;
 652         int i, hash;
 653
 654         tid = ldap_pvt_thread_self();
 655
 656         TID_HASH( tid, hash );
 657         for (i = hash & (LDAP_MAXTHR-1); !TID_EQ(thread_keys[i].id, tid_zero) &&
 658                 !TID_EQ(thread_keys[i].id, tid); i = (i+1) & (LDAP_MAXTHR-1));
 659
 660         return thread_keys[i].ctx;
 661 }
 662
 663 #endif /* LDAP_THREAD_HAVE_TPOOL */