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                 int i;
 226                 ctx = (ldap_int_thread_ctx_t *) LDAP_MALLOC(
 227                         sizeof(ldap_int_thread_ctx_t));
 228                 if (ctx == NULL) {
 229                         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 230                         return(-1);
 231                 }
 232         }
 233
 234         ctx->ltc_start_routine = start_routine;
 235         ctx->ltc_arg = arg;
 236
 237         pool->ltp_pending_count++;
 238         LDAP_STAILQ_INSERT_TAIL(&pool->ltp_pending_list, ctx, ltc_next.q);
 239         if (pool->ltp_state == LDAP_INT_THREAD_POOL_PAUSING) {
 240                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 241                 return(0);
 242         }
 243         ldap_pvt_thread_cond_signal(&pool->ltp_cond);
 244         if ((pool->ltp_open_count <= 0
 245 #if 0
 246                         || pool->ltp_pending_count > 1
 247 #endif
 248                         || pool->ltp_open_count == pool->ltp_active_count)
 249                 && (pool->ltp_max_count <= 0
 250                         || pool->ltp_open_count < pool->ltp_max_count))
 251         {
 252                 pool->ltp_open_count++;
 253                 pool->ltp_starting++;
 254                 need_thread = 1;
 255         }
 256         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 257
 258         if (need_thread) {
 259                 int rc;
 260
 261                 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 262
 263                 rc = ldap_pvt_thread_create( &thr, 1,
 264                         ldap_int_thread_pool_wrapper, pool );
 265                 if (rc == 0) {
 266                         int hash;
 267                         pool->ltp_starting--;
 268
 269                         /* assign this thread ID to a key slot; start
 270                          * at the thread ID itself (mod LDAP_MAXTHR) and
 271                          * look for an empty slot.
 272                          */
 273                         TID_HASH(thr, hash);
 274                         for (rc = hash & (LDAP_MAXTHR-1);
 275                                 !TID_EQ(thread_keys[rc].id, tid_zero);
 276                                 rc = (rc+1) & (LDAP_MAXTHR-1));
 277                         thread_keys[rc].id = thr;
 278                 } else {
 279                         /* couldn't create thread.  back out of
 280                          * ltp_open_count and check for even worse things.
 281                          */
 282                         pool->ltp_open_count--;
 283                         pool->ltp_starting--;
 284                         if (pool->ltp_open_count == 0) {
 285                                 /* no open threads at all?!?
 286                                  */
 287                                 ldap_int_thread_ctx_t *ptr;
 288                                 LDAP_STAILQ_FOREACH(ptr, &pool->ltp_pending_list, ltc_next.q)
 289                                         if (ptr == ctx) break;
 290                                 if (ptr == ctx) {
 291                                         /* no open threads, context not handled, so
 292                                          * back out of ltp_pending_count, free the context,
 293                                          * report the error.
 294                                          */
 295                                         LDAP_STAILQ_REMOVE(&pool->ltp_pending_list, ctx,
 296                                                 ldap_int_thread_ctx_s, ltc_next.q);
 297                                         pool->ltp_pending_count++;
 298                                         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 299                                         LDAP_FREE(ctx);
 300                                         return(-1);
 301                                 }
 302                         }
 303                         /* there is another open thread, so this
 304                          * context will be handled eventually.
 305                          * continue on and signal that the context
 306                          * is waiting.
 307                          */
 308                 }
 309                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 310         }
 311
 312         return(0);
 313 }
 314
 315 int
 316 ldap_pvt_thread_pool_maxthreads ( ldap_pvt_thread_pool_t *tpool, int max_threads )
 317 {
 318         struct ldap_int_thread_pool_s *pool;
 319
 320         if (tpool == NULL)
 321                 return(-1);
 322
 323         pool = *tpool;
 324
 325         if (pool == NULL)
 326                 return(-1);
 327
 328         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 329         pool->ltp_max_count = max_threads;
 330         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 331         return(0);
 332 }
 333
 334 int
 335 ldap_pvt_thread_pool_backload ( ldap_pvt_thread_pool_t *tpool )
 336 {
 337         struct ldap_int_thread_pool_s *pool;
 338         int count;
 339
 340         if (tpool == NULL)
 341                 return(-1);
 342
 343         pool = *tpool;
 344
 345         if (pool == NULL)
 346                 return(0);
 347
 348         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 349         count = pool->ltp_pending_count + pool->ltp_active_count;
 350         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 351         return(count);
 352 }
 353
 354 int
 355 ldap_pvt_thread_pool_destroy ( ldap_pvt_thread_pool_t *tpool, int run_pending )
 356 {
 357         struct ldap_int_thread_pool_s *pool, *pptr;
 358         long waiting;
 359         ldap_int_thread_ctx_t *ctx;
 360
 361         if (tpool == NULL)
 362                 return(-1);
 363
 364         pool = *tpool;
 365
 366         if (pool == NULL) return(-1);
 367
 368         ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
 369         LDAP_STAILQ_FOREACH(pptr, &ldap_int_thread_pool_list, ltp_next)
 370                 if (pptr == pool) break;
 371         if (pptr == pool)
 372                 LDAP_STAILQ_REMOVE(&ldap_int_thread_pool_list, pool,
 373                         ldap_int_thread_pool_s, ltp_next);
 374         ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
 375
 376         if (pool != pptr) return(-1);
 377
 378         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 379         pool->ltp_state = run_pending
 380                 ? LDAP_INT_THREAD_POOL_FINISHING
 381                 : LDAP_INT_THREAD_POOL_STOPPING;
 382
 383         ldap_pvt_thread_cond_broadcast(&pool->ltp_cond);
 384         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 385
 386         do {
 387                 ldap_pvt_thread_yield();
 388                 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 389                 waiting = pool->ltp_open_count;
 390                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 391         } while (waiting > 0);
 392
 393         while ((ctx = LDAP_STAILQ_FIRST(&pool->ltp_pending_list)) != NULL)
 394         {
 395                 LDAP_STAILQ_REMOVE_HEAD(&pool->ltp_pending_list, ltc_next.q);
 396                 LDAP_FREE(ctx);
 397         }
 398
 399         while ((ctx = LDAP_SLIST_FIRST(&pool->ltp_free_list)) != NULL)
 400         {
 401                 LDAP_SLIST_REMOVE_HEAD(&pool->ltp_free_list, ltc_next.l);
 402                 LDAP_FREE(ctx);
 403         }
 404
 405         ldap_pvt_thread_cond_destroy(&pool->ltp_pcond);
 406         ldap_pvt_thread_cond_destroy(&pool->ltp_cond);
 407         ldap_pvt_thread_mutex_destroy(&pool->ltp_mutex);
 408         LDAP_FREE(pool);
 409         return(0);
 410 }
 411
 412 static void *
 413 ldap_int_thread_pool_wrapper (
 414         void *xpool )
 415 {
 416         struct ldap_int_thread_pool_s *pool = xpool;
 417         ldap_int_thread_ctx_t *ctx;
 418         ldap_int_thread_key_t ltc_key[MAXKEYS];
 419         ldap_pvt_thread_t tid;
 420         int i, keyslot, hash;
 421
 422         if (pool == NULL)
 423                 return NULL;
 424
 425         for ( i=0; i<MAXKEYS; i++ ) {
 426                 ltc_key[i].ltk_key = NULL;
 427         }
 428
 429         tid = ldap_pvt_thread_self();
 430
 431         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 432
 433         /* store pointer to our keys */
 434         TID_HASH(tid, hash);
 435         for (i = hash & (LDAP_MAXTHR-1); !TID_EQ(thread_keys[i].id, tid);
 436                                 i = (i+1) & (LDAP_MAXTHR-1));
 437         thread_keys[i].ctx = ltc_key;
 438         keyslot = i;
 439
 440         while (pool->ltp_state != LDAP_INT_THREAD_POOL_STOPPING) {
 441                 ctx = LDAP_STAILQ_FIRST(&pool->ltp_pending_list);
 442                 if (ctx) {
 443                         LDAP_STAILQ_REMOVE_HEAD(&pool->ltp_pending_list, ltc_next.q);
 444                 } else {
 445                         if (pool->ltp_state == LDAP_INT_THREAD_POOL_FINISHING)
 446                                 break;
 447                         if (pool->ltp_max_count > 0
 448                                 && pool->ltp_open_count > pool->ltp_max_count)
 449                         {
 450                                 /* too many threads running (can happen if the
 451                                  * maximum threads value is set during ongoing
 452                                  * operation using ldap_pvt_thread_pool_maxthreads)
 453                                  * so let this thread die.
 454                                  */
 455                                 break;
 456                         }
 457
 458                         /* we could check an idle timer here, and let the
 459                          * thread die if it has been inactive for a while.
 460                          * only die if there are other open threads (i.e.,
 461                          * always have at least one thread open).  the check
 462                          * should be like this:
 463                          *   if (pool->ltp_open_count > 1 && pool->ltp_starting == 0)
 464                          *       check timer, leave thread (break;)
 465                          */
 466
 467                         if (pool->ltp_state == LDAP_INT_THREAD_POOL_RUNNING)
 468                                 ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
 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                 ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 494
 495                 ldap_pvt_thread_yield();
 496
 497                 /* if we use an idle timer, here's
 498                  * a good place to update it
 499                  */
 500
 501                 ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 502         }
 503
 504         for ( i=0; i<MAXKEYS && ltc_key[i].ltk_key; i++ ) {
 505                 if (ltc_key[i].ltk_free)
 506                         ltc_key[i].ltk_free(
 507                                 ltc_key[i].ltk_key,
 508                                 ltc_key[i].ltk_data );
 509         }
 510
 511         thread_keys[keyslot].ctx = NULL;
 512         thread_keys[keyslot].id = tid_zero;
 513
 514         pool->ltp_open_count--;
 515         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 516
 517         ldap_pvt_thread_exit(NULL);
 518         return(NULL);
 519 }
 520
 521 int
 522 ldap_pvt_thread_pool_pause (
 523         ldap_pvt_thread_pool_t *tpool )
 524 {
 525         struct ldap_int_thread_pool_s *pool;
 526
 527         if (tpool == NULL)
 528                 return(-1);
 529
 530         pool = *tpool;
 531
 532         if (pool == NULL)
 533                 return(0);
 534
 535         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 536
 537         /* If someone else has already requested a pause, we have to wait */
 538         if (pool->ltp_state == LDAP_INT_THREAD_POOL_PAUSING) {
 539                 pool->ltp_pending_count++;
 540                 pool->ltp_active_count--;
 541                 ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
 542                 pool->ltp_pending_count--;
 543                 pool->ltp_active_count++;
 544         }
 545         /* Wait for everyone else to finish */
 546         pool->ltp_state = LDAP_INT_THREAD_POOL_PAUSING;
 547         while (pool->ltp_active_count > 1) {
 548                 ldap_pvt_thread_cond_wait(&pool->ltp_pcond, &pool->ltp_mutex);
 549         }
 550         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 551         return(0);
 552 }
 553
 554 int
 555 ldap_pvt_thread_pool_resume (
 556         ldap_pvt_thread_pool_t *tpool )
 557 {
 558         struct ldap_int_thread_pool_s *pool;
 559
 560         if (tpool == NULL)
 561                 return(-1);
 562
 563         pool = *tpool;
 564
 565         if (pool == NULL)
 566                 return(0);
 567
 568         ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
 569
 570         pool->ltp_state = LDAP_INT_THREAD_POOL_RUNNING;
 571         ldap_pvt_thread_cond_broadcast(&pool->ltp_cond);
 572         ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
 573         return(0);
 574 }
 575
 576 int ldap_pvt_thread_pool_getkey(
 577         void *xctx,
 578         void *key,
 579         void **data,
 580         ldap_pvt_thread_pool_keyfree_t **kfree )
 581 {
 582         ldap_int_thread_key_t *ctx = xctx;
 583         int i;
 584
 585         if ( !ctx || !data ) return EINVAL;
 586
 587         for ( i=0; i<MAXKEYS && ctx[i].ltk_key; i++ ) {
 588                 if ( ctx[i].ltk_key == key ) {
 589                         *data = ctx[i].ltk_data;
 590                         if ( kfree ) *kfree = ctx[i].ltk_free;
 591                         return 0;
 592                 }
 593         }
 594         return ENOENT;
 595 }
 596
 597 int ldap_pvt_thread_pool_setkey(
 598         void *xctx,
 599         void *key,
 600         void *data,
 601         ldap_pvt_thread_pool_keyfree_t *kfree )
 602 {
 603         ldap_int_thread_key_t *ctx = xctx;
 604         int i;
 605
 606         if ( !ctx || !key ) return EINVAL;
 607
 608         for ( i=0; i<MAXKEYS; i++ ) {
 609                 if ( !ctx[i].ltk_key || ctx[i].ltk_key == key ) {
 610                         ctx[i].ltk_key = key;
 611                         ctx[i].ltk_data = data;
 612                         ctx[i].ltk_free = kfree;
 613                         return 0;
 614                 }
 615         }
 616         return ENOMEM;
 617 }
 618
 619 /* Free all elements with this key, no matter which thread they're in.
 620  * May only be called while the pool is paused.
 621  */
 622 void ldap_pvt_thread_pool_purgekey( void *key )
 623 {
 624         int i, j;
 625         ldap_int_thread_key_t *ctx;
 626
 627         for ( i=0; i<LDAP_MAXTHR; i++ ) {
 628                 if ( thread_keys[i].ctx ) {
 629                         ctx = thread_keys[i].ctx;
 630                         for ( j=0; j<MAXKEYS; j++ ) {
 631                                 if ( ctx[j].ltk_key == key ) {
 632                                         if (ctx[j].ltk_free)
 633                                                 ctx[j].ltk_free( ctx[j].ltk_key, ctx[j].ltk_data );
 634                                         ctx[j].ltk_key = NULL;
 635                                         ctx[j].ltk_free = NULL;
 636                                         break;
 637                                 }
 638                         }
 639                 }
 640         }
 641 }
 642
 643 /*
 644  * This is necessary if the caller does not have access to the
 645  * thread context handle (for example, a slapd plugin calling
 646  * slapi_search_internal()). No doubt it is more efficient to
 647  * for the application to keep track of the thread context
 648  * handles itself.
 649  */
 650 void *ldap_pvt_thread_pool_context( )
 651 {
 652         ldap_pvt_thread_t tid;
 653         int i, hash;
 654
 655         tid = ldap_pvt_thread_self();
 656
 657         TID_HASH( tid, hash );
 658         for (i = hash & (LDAP_MAXTHR-1); !TID_EQ(thread_keys[i].id, tid_zero) &&
 659                 !TID_EQ(thread_keys[i].id, tid); i = (i+1) & (LDAP_MAXTHR-1));
 660
 661         return thread_keys[i].ctx;
 662 }
 663
 664 #endif /* LDAP_THREAD_HAVE_TPOOL */