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 1998-2006 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 < pool->ltp_active_count + pool->ltp_pending_count
 247                 && (pool->ltp_open_count < pool->ltp_max_count ||
 248                         pool->ltp_max_count <= 0 ))
 249         {
 250                 pool->ltp_open_count++;
 251                 pool->ltp_starting++;
 252                 need_thread = 1;
 253         }
 254         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 255
 256         if (need_thread) {
 257                 int rc;
 258
 259                 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 260
 261                 rc = ldap_pvt_thread_create( &thr, 1,
 262                         ldap_int_thread_pool_wrapper, pool );
 263                 if (rc == 0) {
 264                         int hash;
 265                         pool->ltp_starting--;
 266
 267                         /* assign this thread ID to a key slot; start
 268                          * at the thread ID itself (mod LDAP_MAXTHR) and
 269                          * look for an empty slot.
 270                          */
 271                         TID_HASH(thr, hash);
 272                         for (rc = hash & (LDAP_MAXTHR-1);
 273                                 !ldap_pvt_thread_equal(thread_keys[rc].id, tid_zero);
 274                                 rc = (rc+1) & (LDAP_MAXTHR-1));
 275                         thread_keys[rc].id = thr;
 276                 } else {
 277                         /* couldn't create thread.  back out of
 278                          * ltp_open_count and check for even worse things.
 279                          */
 280                         pool->ltp_open_count--;
 281                         pool->ltp_starting--;
 282                         if (pool->ltp_open_count == 0) {
 283                                 /* no open threads at all?!?
 284                                  */
 285                                 ldap_int_thread_ctx_t *ptr;
 286                                 LDAP_STAILQ_FOREACH(ptr, &pool->ltp_pending_list, ltc_next.q)
 287                                         if (ptr == ctx) break;
 288                                 if (ptr == ctx) {
 289                                         /* no open threads, context not handled, so
 290                                          * back out of ltp_pending_count, free the context,
 291                                          * report the error.
 292                                          */
 293                                         LDAP_STAILQ_REMOVE(&pool->ltp_pending_list, ctx,
 294                                                 ldap_int_thread_ctx_s, ltc_next.q);
 295                                         pool->ltp_pending_count++;
 296                                         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 297                                         LDAP_FREE(ctx);
 298                                         return(-1);
 299                                 }
 300                         }
 301                         /* there is another open thread, so this
 302                          * context will be handled eventually.
 303                          * continue on and signal that the context
 304                          * is waiting.
 305                          */
 306                 }
 307                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 308         }
 309
 310         return(0);
 311 }
 312
 313 int
 314 ldap_pvt_thread_pool_maxthreads ( ldap_pvt_thread_pool_t *tpool, int max_threads )
 315 {
 316         struct ldap_int_thread_pool_s *pool;
 317
 318         if (tpool == NULL)
 319                 return(-1);
 320
 321         pool = *tpool;
 322
 323         if (pool == NULL)
 324                 return(-1);
 325
 326         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 327         pool->ltp_max_count = max_threads;
 328         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 329         return(0);
 330 }
 331
 332 int
 333 ldap_pvt_thread_pool_backload ( ldap_pvt_thread_pool_t *tpool )
 334 {
 335         struct ldap_int_thread_pool_s *pool;
 336         int count;
 337
 338         if (tpool == NULL)
 339                 return(-1);
 340
 341         pool = *tpool;
 342
 343         if (pool == NULL)
 344                 return(0);
 345
 346         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 347         count = pool->ltp_pending_count + pool->ltp_active_count;
 348         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 349         return(count);
 350 }
 351
 352 int
 353 ldap_pvt_thread_pool_destroy ( ldap_pvt_thread_pool_t *tpool, int run_pending )
 354 {
 355         struct ldap_int_thread_pool_s *pool, *pptr;
 356         long waiting;
 357         ldap_int_thread_ctx_t *ctx;
 358
 359         if (tpool == NULL)
 360                 return(-1);
 361
 362         pool = *tpool;
 363
 364         if (pool == NULL) return(-1);
 365
 366         ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
 367         LDAP_STAILQ_FOREACH(pptr, &ldap_int_thread_pool_list, ltp_next)
 368                 if (pptr == pool) break;
 369         if (pptr == pool)
 370                 LDAP_STAILQ_REMOVE(&ldap_int_thread_pool_list, pool,
 371                         ldap_int_thread_pool_s, ltp_next);
 372         ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
 373
 374         if (pool != pptr) return(-1);
 375
 376         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 377         pool->ltp_state = run_pending
 378                 ? LDAP_INT_THREAD_POOL_FINISHING
 379                 : LDAP_INT_THREAD_POOL_STOPPING;
 380
 381         if ( pool->ltp_open_count ) {
 382                 ldap_pvt_thread_cond_broadcast(&pool->ltp_cond);
 383                 ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
 384         }
 385
 386         while ((ctx = LDAP_STAILQ_FIRST(&pool->ltp_pending_list)) != NULL)
 387         {
 388                 LDAP_STAILQ_REMOVE_HEAD(&pool->ltp_pending_list, ltc_next.q);
 389                 LDAP_FREE(ctx);
 390         }
 391
 392         while ((ctx = LDAP_SLIST_FIRST(&pool->ltp_free_list)) != NULL)
 393         {
 394                 LDAP_SLIST_REMOVE_HEAD(&pool->ltp_free_list, ltc_next.l);
 395                 LDAP_FREE(ctx);
 396         }
 397
 398         ldap_pvt_thread_cond_destroy(&pool->ltp_pcond);
 399         ldap_pvt_thread_cond_destroy(&pool->ltp_cond);
 400         ldap_pvt_thread_mutex_destroy(&pool->ltp_mutex);
 401         LDAP_FREE(pool);
 402         return(0);
 403 }
 404
 405 static void *
 406 ldap_int_thread_pool_wrapper (
 407         void *xpool )
 408 {
 409         struct ldap_int_thread_pool_s *pool = xpool;
 410         ldap_int_thread_ctx_t *ctx;
 411         ldap_int_thread_key_t ltc_key[MAXKEYS];
 412         ldap_pvt_thread_t tid;
 413         int i, keyslot, hash;
 414
 415         if (pool == NULL)
 416                 return NULL;
 417
 418         for ( i=0; i<MAXKEYS; i++ ) {
 419                 ltc_key[i].ltk_key = NULL;
 420         }
 421
 422         tid = ldap_pvt_thread_self();
 423
 424         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 425
 426         /* store pointer to our keys */
 427         TID_HASH(tid, hash);
 428         for (i = hash & (LDAP_MAXTHR-1);
 429                                 !ldap_pvt_thread_equal(thread_keys[i].id, tid);
 430                                 i = (i+1) & (LDAP_MAXTHR-1));
 431         thread_keys[i].ctx = ltc_key;
 432         keyslot = i;
 433
 434         while (pool->ltp_state != LDAP_INT_THREAD_POOL_STOPPING) {
 435                 ctx = LDAP_STAILQ_FIRST(&pool->ltp_pending_list);
 436                 if (ctx) {
 437                         LDAP_STAILQ_REMOVE_HEAD(&pool->ltp_pending_list, ltc_next.q);
 438                 } else {
 439                         if (pool->ltp_state == LDAP_INT_THREAD_POOL_FINISHING)
 440                                 break;
 441                         if (pool->ltp_max_count > 0
 442                                 && pool->ltp_open_count > pool->ltp_max_count)
 443                         {
 444                                 /* too many threads running (can happen if the
 445                                  * maximum threads value is set during ongoing
 446                                  * operation using ldap_pvt_thread_pool_maxthreads)
 447                                  * so let this thread die.
 448                                  */
 449                                 break;
 450                         }
 451
 452                         /* we could check an idle timer here, and let the
 453                          * thread die if it has been inactive for a while.
 454                          * only die if there are other open threads (i.e.,
 455                          * always have at least one thread open).  the check
 456                          * should be like this:
 457                          *   if (pool->ltp_open_count > 1 && pool->ltp_starting == 0)
 458                          *       check timer, leave thread (break;)
 459                          *
 460                          * Just use pthread_cond_timedwait if we want to
 461                          * check idle time.
 462                          */
 463
 464                         if (pool->ltp_state == LDAP_INT_THREAD_POOL_RUNNING
 465                                 || pool->ltp_state == LDAP_INT_THREAD_POOL_PAUSING)
 466                         {
 467                                 ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
 468                         }
 469
 470                         continue;
 471                 }
 472
 473                 pool->ltp_pending_count--;
 474
 475                 LDAP_SLIST_INSERT_HEAD(&pool->ltp_active_list, ctx, ltc_next.al);
 476                 pool->ltp_active_count++;
 477                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 478
 479                 ctx->ltc_start_routine(ltc_key, ctx->ltc_arg);
 480
 481                 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 482                 LDAP_SLIST_REMOVE(&pool->ltp_active_list, ctx,
 483                         ldap_int_thread_ctx_s, ltc_next.al);
 484                 LDAP_SLIST_INSERT_HEAD(&pool->ltp_free_list, ctx, ltc_next.l);
 485                 pool->ltp_active_count--;
 486
 487                 if (pool->ltp_state == LDAP_INT_THREAD_POOL_PAUSING) {
 488                         if (pool->ltp_active_count < 2) {
 489                                 ldap_pvt_thread_cond_signal(&pool->ltp_pcond);
 490                         }
 491                         ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
 492                 }
 493         }
 494
 495         for ( i=0; i<MAXKEYS && ltc_key[i].ltk_key; i++ ) {
 496                 if (ltc_key[i].ltk_free)
 497                         ltc_key[i].ltk_free(
 498                                 ltc_key[i].ltk_key,
 499                                 ltc_key[i].ltk_data );
 500         }
 501
 502         thread_keys[keyslot].ctx = NULL;
 503         thread_keys[keyslot].id = tid_zero;
 504
 505         pool->ltp_open_count--;
 506
 507         /* let pool_destroy know we're all done */
 508         if (pool->ltp_open_count < 1)
 509                 ldap_pvt_thread_cond_signal(&pool->ltp_cond);
 510
 511         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 512
 513         ldap_pvt_thread_exit(NULL);
 514         return(NULL);
 515 }
 516
 517 int
 518 ldap_pvt_thread_pool_pause (
 519         ldap_pvt_thread_pool_t *tpool )
 520 {
 521         struct ldap_int_thread_pool_s *pool;
 522
 523         if (tpool == NULL)
 524                 return(-1);
 525
 526         pool = *tpool;
 527
 528         if (pool == NULL)
 529                 return(0);
 530
 531         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 532
 533         /* If someone else has already requested a pause, we have to wait */
 534         while (pool->ltp_state == LDAP_INT_THREAD_POOL_PAUSING) {
 535                 pool->ltp_pending_count++;
 536                 pool->ltp_active_count--;
 537                 ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
 538                 pool->ltp_pending_count--;
 539                 pool->ltp_active_count++;
 540         }
 541         /* Wait for everyone else to finish */
 542         pool->ltp_state = LDAP_INT_THREAD_POOL_PAUSING;
 543         while (pool->ltp_active_count > 1) {
 544                 ldap_pvt_thread_cond_wait(&pool->ltp_pcond, &pool->ltp_mutex);
 545         }
 546         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 547         return(0);
 548 }
 549
 550 int
 551 ldap_pvt_thread_pool_resume (
 552         ldap_pvt_thread_pool_t *tpool )
 553 {
 554         struct ldap_int_thread_pool_s *pool;
 555
 556         if (tpool == NULL)
 557                 return(-1);
 558
 559         pool = *tpool;
 560
 561         if (pool == NULL)
 562                 return(0);
 563
 564         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 565
 566         pool->ltp_state = LDAP_INT_THREAD_POOL_RUNNING;
 567         ldap_pvt_thread_cond_broadcast(&pool->ltp_cond);
 568         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 569         return(0);
 570 }
 571
 572 int ldap_pvt_thread_pool_getkey(
 573         void *xctx,
 574         void *key,
 575         void **data,
 576         ldap_pvt_thread_pool_keyfree_t **kfree )
 577 {
 578         ldap_int_thread_key_t *ctx = xctx;
 579         int i;
 580
 581         if ( !ctx || !data ) return EINVAL;
 582
 583         for ( i=0; i<MAXKEYS && ctx[i].ltk_key; i++ ) {
 584                 if ( ctx[i].ltk_key == key ) {
 585                         *data = ctx[i].ltk_data;
 586                         if ( kfree ) *kfree = ctx[i].ltk_free;
 587                         return 0;
 588                 }
 589         }
 590         return ENOENT;
 591 }
 592
 593 int ldap_pvt_thread_pool_setkey(
 594         void *xctx,
 595         void *key,
 596         void *data,
 597         ldap_pvt_thread_pool_keyfree_t *kfree )
 598 {
 599         ldap_int_thread_key_t *ctx = xctx;
 600         int i;
 601
 602         if ( !ctx || !key ) return EINVAL;
 603
 604         for ( i=0; i<MAXKEYS; i++ ) {
 605                 if ( !ctx[i].ltk_key || ctx[i].ltk_key == key ) {
 606                         ctx[i].ltk_key = key;
 607                         ctx[i].ltk_data = data;
 608                         ctx[i].ltk_free = kfree;
 609                         return 0;
 610                 }
 611         }
 612         return ENOMEM;
 613 }
 614
 615 /* Free all elements with this key, no matter which thread they're in.
 616  * May only be called while the pool is paused.
 617  */
 618 void ldap_pvt_thread_pool_purgekey( void *key )
 619 {
 620         int i, j;
 621         ldap_int_thread_key_t *ctx;
 622
 623         for ( i=0; i<LDAP_MAXTHR; i++ ) {
 624                 if ( thread_keys[i].ctx ) {
 625                         ctx = thread_keys[i].ctx;
 626                         for ( j=0; j<MAXKEYS; j++ ) {
 627                                 if ( ctx[j].ltk_key == key ) {
 628                                         if (ctx[j].ltk_free)
 629                                                 ctx[j].ltk_free( ctx[j].ltk_key, ctx[j].ltk_data );
 630                                         ctx[j].ltk_key = NULL;
 631                                         ctx[j].ltk_free = NULL;
 632                                         break;
 633                                 }
 634                         }
 635                 }
 636         }
 637 }
 638
 639 /*
 640  * This is necessary if the caller does not have access to the
 641  * thread context handle (for example, a slapd plugin calling
 642  * slapi_search_internal()). No doubt it is more efficient to
 643  * for the application to keep track of the thread context
 644  * handles itself.
 645  */
 646 void *ldap_pvt_thread_pool_context( )
 647 {
 648         ldap_pvt_thread_t tid;
 649         int i, hash;
 650
 651         tid = ldap_pvt_thread_self();
 652         if ( ldap_pvt_thread_equal( tid, ldap_int_main_tid ))
 653                 return ldap_int_main_thrctx;
 654
 655         TID_HASH( tid, hash );
 656         for (i = hash & (LDAP_MAXTHR-1);
 657                 !ldap_pvt_thread_equal(thread_keys[i].id, tid_zero) &&
 658                 !ldap_pvt_thread_equal(thread_keys[i].id, tid);
 659                 i = (i+1) & (LDAP_MAXTHR-1));
 660
 661         return thread_keys[i].ctx;
 662 }
 663
 664 void ldap_pvt_thread_pool_context_reset( void *vctx )
 665 {
 666         ldap_int_thread_key_t *ctx = vctx;
 667         int i;
 668
 669         for ( i=0; i<MAXKEYS && ctx[i].ltk_key; i++) {
 670                 if ( ctx[i].ltk_free )
 671                         ctx[i].ltk_free( ctx[i].ltk_key, ctx[i].ltk_data );
 672                 ctx[i].ltk_key = NULL;
 673         }
 674 }
 675 #endif /* LDAP_THREAD_HAVE_TPOOL */