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" /* Get the thread interface */
  28 #include "ldap_queue.h"
  29 #define LDAP_THREAD_POOL_IMPLEMENTATION
  30 #include "ldap_thr_debug.h"  /* May rename symbols defined below */
  31
  32 #ifndef LDAP_THREAD_HAVE_TPOOL
  33
  34 typedef enum ldap_int_thread_pool_state_e {
  35         LDAP_INT_THREAD_POOL_RUNNING,
  36         LDAP_INT_THREAD_POOL_FINISHING,
  37         LDAP_INT_THREAD_POOL_STOPPING,
  38         LDAP_INT_THREAD_POOL_PAUSING
  39 } ldap_int_thread_pool_state_t;
  40
  41 typedef struct ldap_int_thread_key_s {
  42         void *ltk_key;
  43         void *ltk_data;
  44         ldap_pvt_thread_pool_keyfree_t *ltk_free;
  45 } ldap_int_thread_key_t;
  46
  47 /* Max number of thread-specific keys we store per thread.
  48  * We don't expect to use many...
  49  */
  50 #define MAXKEYS 32
  51 #define LDAP_MAXTHR     1024    /* must be a power of 2 */
  52
  53 static ldap_pvt_thread_t tid_zero;
  54
  55 static struct {
  56         ldap_pvt_thread_t id;
  57         ldap_int_thread_key_t *ctx;
  58 } thread_keys[LDAP_MAXTHR];
  59
  60
  61 typedef struct ldap_int_thread_ctx_s {
  62         union {
  63         LDAP_STAILQ_ENTRY(ldap_int_thread_ctx_s) q;
  64         LDAP_SLIST_ENTRY(ldap_int_thread_ctx_s) l;
  65         LDAP_SLIST_ENTRY(ldap_int_thread_ctx_s) al;
  66         } ltc_next;
  67         ldap_pvt_thread_start_t *ltc_start_routine;
  68         void *ltc_arg;
  69 } ldap_int_thread_ctx_t;
  70
  71 struct ldap_int_thread_pool_s {
  72         LDAP_STAILQ_ENTRY(ldap_int_thread_pool_s) ltp_next;
  73         ldap_pvt_thread_mutex_t ltp_mutex;
  74         ldap_pvt_thread_cond_t ltp_cond;
  75         ldap_pvt_thread_cond_t ltp_pcond;
  76         LDAP_STAILQ_HEAD(tcq, ldap_int_thread_ctx_s) ltp_pending_list;
  77         LDAP_SLIST_HEAD(tcl, ldap_int_thread_ctx_s) ltp_free_list;
  78         LDAP_SLIST_HEAD(tclq, ldap_int_thread_ctx_s) ltp_active_list;
  79         ldap_int_thread_pool_state_t ltp_state;
  80         long ltp_max_count;
  81         long ltp_max_pending;
  82         long ltp_pending_count;
  83         long ltp_active_count;
  84         long ltp_open_count;
  85         long ltp_starting;
  86 };
  87
  88 static LDAP_STAILQ_HEAD(tpq, ldap_int_thread_pool_s)
  89         ldap_int_thread_pool_list =
  90         LDAP_STAILQ_HEAD_INITIALIZER(ldap_int_thread_pool_list);
  91
  92 static ldap_pvt_thread_mutex_t ldap_pvt_thread_pool_mutex;
  93
  94 static void *ldap_int_thread_pool_wrapper( void *pool );
  95
  96 static ldap_pvt_thread_t ldap_int_main_tid;
  97
  98 static ldap_int_thread_key_t ldap_int_main_thrctx[LDAP_MAXTHR];
  99
 100 int
 101 ldap_int_thread_pool_startup ( void )
 102 {
 103         ldap_int_main_tid = ldap_pvt_thread_self();
 104
 105         return ldap_pvt_thread_mutex_init(&ldap_pvt_thread_pool_mutex);
 106 }
 107
 108 int
 109 ldap_int_thread_pool_shutdown ( void )
 110 {
 111         struct ldap_int_thread_pool_s *pool;
 112
 113         while ((pool = LDAP_STAILQ_FIRST(&ldap_int_thread_pool_list)) != NULL) {
 114                 LDAP_STAILQ_REMOVE_HEAD(&ldap_int_thread_pool_list, ltp_next);
 115                 (ldap_pvt_thread_pool_destroy)(&pool, 0); /* ignore thr_debug macro */
 116         }
 117         ldap_pvt_thread_mutex_destroy(&ldap_pvt_thread_pool_mutex);
 118         return(0);
 119 }
 120
 121 int
 122 ldap_pvt_thread_pool_init (
 123         ldap_pvt_thread_pool_t *tpool,
 124         int max_threads,
 125         int max_pending )
 126 {
 127         ldap_pvt_thread_pool_t pool;
 128         int rc;
 129
 130         *tpool = NULL;
 131         pool = (ldap_pvt_thread_pool_t) LDAP_CALLOC(1,
 132                 sizeof(struct ldap_int_thread_pool_s));
 133
 134         if (pool == NULL) return(-1);
 135
 136         rc = ldap_pvt_thread_mutex_init(&pool->ltp_mutex);
 137         if (rc != 0)
 138                 return(rc);
 139         rc = ldap_pvt_thread_cond_init(&pool->ltp_cond);
 140         if (rc != 0)
 141                 return(rc);
 142         rc = ldap_pvt_thread_cond_init(&pool->ltp_pcond);
 143         if (rc != 0)
 144                 return(rc);
 145         pool->ltp_state = LDAP_INT_THREAD_POOL_RUNNING;
 146         pool->ltp_max_count = max_threads;
 147         pool->ltp_max_pending = max_pending;
 148         LDAP_STAILQ_INIT(&pool->ltp_pending_list);
 149         LDAP_SLIST_INIT(&pool->ltp_free_list);
 150         LDAP_SLIST_INIT(&pool->ltp_active_list);
 151         ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
 152         LDAP_STAILQ_INSERT_TAIL(&ldap_int_thread_pool_list, pool, ltp_next);
 153         ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
 154
 155 #if 0
 156         /* THIS WILL NOT WORK on some systems.  If the process
 157          * forks after starting a thread, there is no guarantee
 158          * that the thread will survive the fork.  For example,
 159          * slapd forks in order to daemonize, and does so after
 160          * calling ldap_pvt_thread_pool_init.  On some systems,
 161          * this initial thread does not run in the child process,
 162          * but ltp_open_count == 1, so two things happen:
 163          * 1) the first client connection fails, and 2) when
 164          * slapd is kill'ed, it never terminates since it waits
 165          * for all worker threads to exit. */
 166
 167         /* start up one thread, just so there is one. no need to
 168          * lock the mutex right now, since no threads are running.
 169          */
 170         pool->ltp_open_count++;
 171
 172         ldap_pvt_thread_t thr;
 173         rc = ldap_pvt_thread_create( &thr, 1, ldap_int_thread_pool_wrapper, pool );
 174
 175         if( rc != 0) {
 176                 /* couldn't start one?  then don't start any */
 177                 ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
 178                 LDAP_STAILQ_REMOVE(ldap_int_thread_pool_list, pool,
 179                         ldap_int_thread_pool_s, ltp_next);
 180                 ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
 181                 ldap_pvt_thread_cond_destroy(&pool->ltp_pcond);
 182                 ldap_pvt_thread_cond_destroy(&pool->ltp_cond);
 183                 ldap_pvt_thread_mutex_destroy(&pool->ltp_mutex);
 184                 LDAP_FREE(pool);
 185                 return(-1);
 186         }
 187 #endif
 188
 189         *tpool = pool;
 190         return(0);
 191 }
 192
 193 #define TID_HASH(tid, hash) do { unsigned i; \
 194         unsigned char *ptr = (unsigned char *)&(tid); \
 195         for (i=0, hash=0; i<sizeof(tid); i++) hash += ptr[i]; } while(0)
 196
 197 int
 198 ldap_pvt_thread_pool_submit (
 199         ldap_pvt_thread_pool_t *tpool,
 200         ldap_pvt_thread_start_t *start_routine, void *arg )
 201 {
 202         struct ldap_int_thread_pool_s *pool;
 203         ldap_int_thread_ctx_t *ctx;
 204         int need_thread = 0;
 205         ldap_pvt_thread_t thr;
 206
 207         if (tpool == NULL)
 208                 return(-1);
 209
 210         pool = *tpool;
 211
 212         if (pool == NULL)
 213                 return(-1);
 214
 215         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 216         if ((pool->ltp_state != LDAP_INT_THREAD_POOL_RUNNING &&
 217                 pool->ltp_state != LDAP_INT_THREAD_POOL_PAUSING)
 218                 || (pool->ltp_max_pending > 0
 219                         && pool->ltp_pending_count >= pool->ltp_max_pending))
 220         {
 221                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 222                 return(-1);
 223         }
 224         ctx = LDAP_SLIST_FIRST(&pool->ltp_free_list);
 225         if (ctx) {
 226                 LDAP_SLIST_REMOVE_HEAD(&pool->ltp_free_list, ltc_next.l);
 227         } else {
 228                 ctx = (ldap_int_thread_ctx_t *) LDAP_MALLOC(
 229                         sizeof(ldap_int_thread_ctx_t));
 230                 if (ctx == NULL) {
 231                         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 232                         return(-1);
 233                 }
 234         }
 235
 236         ctx->ltc_start_routine = start_routine;
 237         ctx->ltc_arg = arg;
 238
 239         pool->ltp_pending_count++;
 240         LDAP_STAILQ_INSERT_TAIL(&pool->ltp_pending_list, ctx, ltc_next.q);
 241         if (pool->ltp_state == LDAP_INT_THREAD_POOL_PAUSING) {
 242                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 243                 return(0);
 244         }
 245         ldap_pvt_thread_cond_signal(&pool->ltp_cond);
 246         if ((pool->ltp_open_count <= 0
 247 #if 0
 248                         || pool->ltp_pending_count > 1
 249 #endif
 250                         || pool->ltp_open_count == pool->ltp_active_count)
 251                 && (pool->ltp_max_count <= 0
 252                         || pool->ltp_open_count < pool->ltp_max_count))
 253         {
 254                 pool->ltp_open_count++;
 255                 pool->ltp_starting++;
 256                 need_thread = 1;
 257         }
 258         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 259
 260         if (need_thread) {
 261                 int rc;
 262
 263                 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 264
 265                 rc = ldap_pvt_thread_create( &thr, 1,
 266                         ldap_int_thread_pool_wrapper, pool );
 267                 if (rc == 0) {
 268                         int hash;
 269                         pool->ltp_starting--;
 270
 271                         /* assign this thread ID to a key slot; start
 272                          * at the thread ID itself (mod LDAP_MAXTHR) and
 273                          * look for an empty slot.
 274                          */
 275                         TID_HASH(thr, hash);
 276                         for (rc = hash & (LDAP_MAXTHR-1);
 277                                 !ldap_pvt_thread_equal(thread_keys[rc].id, tid_zero);
 278                                 rc = (rc+1) & (LDAP_MAXTHR-1));
 279                         thread_keys[rc].id = thr;
 280                 } else {
 281                         /* couldn't create thread.  back out of
 282                          * ltp_open_count and check for even worse things.
 283                          */
 284                         pool->ltp_open_count--;
 285                         pool->ltp_starting--;
 286                         if (pool->ltp_open_count == 0) {
 287                                 /* no open threads at all?!?
 288                                  */
 289                                 ldap_int_thread_ctx_t *ptr;
 290                                 LDAP_STAILQ_FOREACH(ptr, &pool->ltp_pending_list, ltc_next.q)
 291                                         if (ptr == ctx) break;
 292                                 if (ptr == ctx) {
 293                                         /* no open threads, context not handled, so
 294                                          * back out of ltp_pending_count, free the context,
 295                                          * report the error.
 296                                          */
 297                                         LDAP_STAILQ_REMOVE(&pool->ltp_pending_list, ctx,
 298                                                 ldap_int_thread_ctx_s, ltc_next.q);
 299                                         pool->ltp_pending_count++;
 300                                         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 301                                         LDAP_FREE(ctx);
 302                                         return(-1);
 303                                 }
 304                         }
 305                         /* there is another open thread, so this
 306                          * context will be handled eventually.
 307                          * continue on and signal that the context
 308                          * is waiting.
 309                          */
 310                 }
 311                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 312         }
 313
 314         return(0);
 315 }
 316
 317 int
 318 ldap_pvt_thread_pool_maxthreads ( ldap_pvt_thread_pool_t *tpool, int max_threads )
 319 {
 320         struct ldap_int_thread_pool_s *pool;
 321
 322         if (tpool == NULL)
 323                 return(-1);
 324
 325         pool = *tpool;
 326
 327         if (pool == NULL)
 328                 return(-1);
 329
 330         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 331         pool->ltp_max_count = max_threads;
 332         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 333         return(0);
 334 }
 335
 336 int
 337 ldap_pvt_thread_pool_backload ( ldap_pvt_thread_pool_t *tpool )
 338 {
 339         struct ldap_int_thread_pool_s *pool;
 340         int count;
 341
 342         if (tpool == NULL)
 343                 return(-1);
 344
 345         pool = *tpool;
 346
 347         if (pool == NULL)
 348                 return(0);
 349
 350         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 351         count = pool->ltp_pending_count + pool->ltp_active_count;
 352         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 353         return(count);
 354 }
 355
 356 int
 357 ldap_pvt_thread_pool_destroy ( ldap_pvt_thread_pool_t *tpool, int run_pending )
 358 {
 359         struct ldap_int_thread_pool_s *pool, *pptr;
 360         long waiting;
 361         ldap_int_thread_ctx_t *ctx;
 362
 363         if (tpool == NULL)
 364                 return(-1);
 365
 366         pool = *tpool;
 367
 368         if (pool == NULL) return(-1);
 369
 370         ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
 371         LDAP_STAILQ_FOREACH(pptr, &ldap_int_thread_pool_list, ltp_next)
 372                 if (pptr == pool) break;
 373         if (pptr == pool)
 374                 LDAP_STAILQ_REMOVE(&ldap_int_thread_pool_list, pool,
 375                         ldap_int_thread_pool_s, ltp_next);
 376         ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
 377
 378         if (pool != pptr) return(-1);
 379
 380         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 381         pool->ltp_state = run_pending
 382                 ? LDAP_INT_THREAD_POOL_FINISHING
 383                 : LDAP_INT_THREAD_POOL_STOPPING;
 384
 385         ldap_pvt_thread_cond_broadcast(&pool->ltp_cond);
 386         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 387
 388         do {
 389                 ldap_pvt_thread_yield();
 390                 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 391                 waiting = pool->ltp_open_count;
 392                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 393         } while (waiting > 0);
 394
 395         while ((ctx = LDAP_STAILQ_FIRST(&pool->ltp_pending_list)) != NULL)
 396         {
 397                 LDAP_STAILQ_REMOVE_HEAD(&pool->ltp_pending_list, ltc_next.q);
 398                 LDAP_FREE(ctx);
 399         }
 400
 401         while ((ctx = LDAP_SLIST_FIRST(&pool->ltp_free_list)) != NULL)
 402         {
 403                 LDAP_SLIST_REMOVE_HEAD(&pool->ltp_free_list, ltc_next.l);
 404                 LDAP_FREE(ctx);
 405         }
 406
 407         ldap_pvt_thread_cond_destroy(&pool->ltp_pcond);
 408         ldap_pvt_thread_cond_destroy(&pool->ltp_cond);
 409         ldap_pvt_thread_mutex_destroy(&pool->ltp_mutex);
 410         LDAP_FREE(pool);
 411         return(0);
 412 }
 413
 414 static void *
 415 ldap_int_thread_pool_wrapper (
 416         void *xpool )
 417 {
 418         struct ldap_int_thread_pool_s *pool = xpool;
 419         ldap_int_thread_ctx_t *ctx;
 420         ldap_int_thread_key_t ltc_key[MAXKEYS];
 421         ldap_pvt_thread_t tid;
 422         int i, keyslot, hash;
 423
 424         if (pool == NULL)
 425                 return NULL;
 426
 427         for ( i=0; i<MAXKEYS; i++ ) {
 428                 ltc_key[i].ltk_key = NULL;
 429         }
 430
 431         tid = ldap_pvt_thread_self();
 432
 433         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 434
 435         /* store pointer to our keys */
 436         TID_HASH(tid, hash);
 437         for (i = hash & (LDAP_MAXTHR-1);
 438                                 !ldap_pvt_thread_equal(thread_keys[i].id, tid);
 439                                 i = (i+1) & (LDAP_MAXTHR-1));
 440         thread_keys[i].ctx = ltc_key;
 441         keyslot = i;
 442
 443         while (pool->ltp_state != LDAP_INT_THREAD_POOL_STOPPING) {
 444                 ctx = LDAP_STAILQ_FIRST(&pool->ltp_pending_list);
 445                 if (ctx) {
 446                         LDAP_STAILQ_REMOVE_HEAD(&pool->ltp_pending_list, ltc_next.q);
 447                 } else {
 448                         if (pool->ltp_state == LDAP_INT_THREAD_POOL_FINISHING)
 449                                 break;
 450                         if (pool->ltp_max_count > 0
 451                                 && pool->ltp_open_count > pool->ltp_max_count)
 452                         {
 453                                 /* too many threads running (can happen if the
 454                                  * maximum threads value is set during ongoing
 455                                  * operation using ldap_pvt_thread_pool_maxthreads)
 456                                  * so let this thread die.
 457                                  */
 458                                 break;
 459                         }
 460
 461                         /* we could check an idle timer here, and let the
 462                          * thread die if it has been inactive for a while.
 463                          * only die if there are other open threads (i.e.,
 464                          * always have at least one thread open).  the check
 465                          * should be like this:
 466                          *   if (pool->ltp_open_count > 1 && pool->ltp_starting == 0)
 467                          *       check timer, leave thread (break;)
 468                          */
 469
 470                         if (pool->ltp_state == LDAP_INT_THREAD_POOL_RUNNING
 471                                 || pool->ltp_state == LDAP_INT_THREAD_POOL_PAUSING)
 472                         {
 473                                 ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
 474                         }
 475
 476                         continue;
 477                 }
 478
 479                 pool->ltp_pending_count--;
 480
 481                 LDAP_SLIST_INSERT_HEAD(&pool->ltp_active_list, ctx, ltc_next.al);
 482                 pool->ltp_active_count++;
 483                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 484
 485                 ctx->ltc_start_routine(ltc_key, ctx->ltc_arg);
 486
 487                 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 488                 LDAP_SLIST_REMOVE(&pool->ltp_active_list, ctx,
 489                         ldap_int_thread_ctx_s, ltc_next.al);
 490                 LDAP_SLIST_INSERT_HEAD(&pool->ltp_free_list, ctx, ltc_next.l);
 491                 pool->ltp_active_count--;
 492
 493                 if (pool->ltp_state == LDAP_INT_THREAD_POOL_PAUSING) {
 494                         if (pool->ltp_active_count < 2) {
 495                                 ldap_pvt_thread_cond_signal(&pool->ltp_pcond);
 496                         }
 497                         ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
 498                 }
 499                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 500
 501                 ldap_pvt_thread_yield();
 502
 503                 /* if we use an idle timer, here's
 504                  * a good place to update it
 505                  */
 506
 507                 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 508         }
 509
 510         for ( i=0; i<MAXKEYS && ltc_key[i].ltk_key; i++ ) {
 511                 if (ltc_key[i].ltk_free)
 512                         ltc_key[i].ltk_free(
 513                                 ltc_key[i].ltk_key,
 514                                 ltc_key[i].ltk_data );
 515         }
 516
 517         thread_keys[keyslot].ctx = NULL;
 518         thread_keys[keyslot].id = tid_zero;
 519
 520         pool->ltp_open_count--;
 521         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 522
 523         ldap_pvt_thread_exit(NULL);
 524         return(NULL);
 525 }
 526
 527 int
 528 ldap_pvt_thread_pool_pause (
 529         ldap_pvt_thread_pool_t *tpool )
 530 {
 531         struct ldap_int_thread_pool_s *pool;
 532
 533         if (tpool == NULL)
 534                 return(-1);
 535
 536         pool = *tpool;
 537
 538         if (pool == NULL)
 539                 return(0);
 540
 541         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 542
 543         /* If someone else has already requested a pause, we have to wait */
 544         while (pool->ltp_state == LDAP_INT_THREAD_POOL_PAUSING) {
 545                 pool->ltp_pending_count++;
 546                 pool->ltp_active_count--;
 547                 ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
 548                 pool->ltp_pending_count--;
 549                 pool->ltp_active_count++;
 550         }
 551         /* Wait for everyone else to finish */
 552         pool->ltp_state = LDAP_INT_THREAD_POOL_PAUSING;
 553         while (pool->ltp_active_count > 1) {
 554                 ldap_pvt_thread_cond_wait(&pool->ltp_pcond, &pool->ltp_mutex);
 555         }
 556         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 557         return(0);
 558 }
 559
 560 int
 561 ldap_pvt_thread_pool_resume (
 562         ldap_pvt_thread_pool_t *tpool )
 563 {
 564         struct ldap_int_thread_pool_s *pool;
 565
 566         if (tpool == NULL)
 567                 return(-1);
 568
 569         pool = *tpool;
 570
 571         if (pool == NULL)
 572                 return(0);
 573
 574         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 575
 576         pool->ltp_state = LDAP_INT_THREAD_POOL_RUNNING;
 577         ldap_pvt_thread_cond_broadcast(&pool->ltp_cond);
 578         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 579         return(0);
 580 }
 581
 582 int ldap_pvt_thread_pool_getkey(
 583         void *xctx,
 584         void *key,
 585         void **data,
 586         ldap_pvt_thread_pool_keyfree_t **kfree )
 587 {
 588         ldap_int_thread_key_t *ctx = xctx;
 589         int i;
 590
 591         if ( !ctx || !data ) return EINVAL;
 592
 593         for ( i=0; i<MAXKEYS && ctx[i].ltk_key; i++ ) {
 594                 if ( ctx[i].ltk_key == key ) {
 595                         *data = ctx[i].ltk_data;
 596                         if ( kfree ) *kfree = ctx[i].ltk_free;
 597                         return 0;
 598                 }
 599         }
 600         return ENOENT;
 601 }
 602
 603 int ldap_pvt_thread_pool_setkey(
 604         void *xctx,
 605         void *key,
 606         void *data,
 607         ldap_pvt_thread_pool_keyfree_t *kfree )
 608 {
 609         ldap_int_thread_key_t *ctx = xctx;
 610         int i;
 611
 612         if ( !ctx || !key ) return EINVAL;
 613
 614         for ( i=0; i<MAXKEYS; i++ ) {
 615                 if ( !ctx[i].ltk_key || ctx[i].ltk_key == key ) {
 616                         ctx[i].ltk_key = key;
 617                         ctx[i].ltk_data = data;
 618                         ctx[i].ltk_free = kfree;
 619                         return 0;
 620                 }
 621         }
 622         return ENOMEM;
 623 }
 624
 625 /* Free all elements with this key, no matter which thread they're in.
 626  * May only be called while the pool is paused.
 627  */
 628 void ldap_pvt_thread_pool_purgekey( void *key )
 629 {
 630         int i, j;
 631         ldap_int_thread_key_t *ctx;
 632
 633         for ( i=0; i<LDAP_MAXTHR; i++ ) {
 634                 if ( thread_keys[i].ctx ) {
 635                         ctx = thread_keys[i].ctx;
 636                         for ( j=0; j<MAXKEYS; j++ ) {
 637                                 if ( ctx[j].ltk_key == key ) {
 638                                         if (ctx[j].ltk_free)
 639                                                 ctx[j].ltk_free( ctx[j].ltk_key, ctx[j].ltk_data );
 640                                         ctx[j].ltk_key = NULL;
 641                                         ctx[j].ltk_free = NULL;
 642                                         break;
 643                                 }
 644                         }
 645                 }
 646         }
 647 }
 648
 649 /*
 650  * This is necessary if the caller does not have access to the
 651  * thread context handle (for example, a slapd plugin calling
 652  * slapi_search_internal()). No doubt it is more efficient to
 653  * for the application to keep track of the thread context
 654  * handles itself.
 655  */
 656 void *ldap_pvt_thread_pool_context( )
 657 {
 658         ldap_pvt_thread_t tid;
 659         int i, hash;
 660
 661         tid = ldap_pvt_thread_self();
 662         if ( ldap_pvt_thread_equal( tid, ldap_int_main_tid ))
 663                 return ldap_int_main_thrctx;
 664
 665         TID_HASH( tid, hash );
 666         for (i = hash & (LDAP_MAXTHR-1);
 667                 !ldap_pvt_thread_equal(thread_keys[i].id, tid_zero) &&
 668                 !ldap_pvt_thread_equal(thread_keys[i].id, tid);
 669                 i = (i+1) & (LDAP_MAXTHR-1));
 670
 671         return thread_keys[i].ctx;
 672 }
 673
 674 void ldap_pvt_thread_pool_context_reset( void *vctx )
 675 {
 676         ldap_int_thread_key_t *ctx = vctx;
 677         int i;
 678
 679         for ( i=0; i<MAXKEYS && ctx[i].ltk_key; i++) {
 680                 if ( ctx[i].ltk_free )
 681                         ctx[i].ltk_free( ctx[i].ltk_key, ctx[i].ltk_data );
 682                 ctx[i].ltk_key = NULL;
 683         }
 684 }
 685 #endif /* LDAP_THREAD_HAVE_TPOOL */