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-rw-r--r--libraries/libldap_r/tpool.c1032
1 files changed, 1032 insertions, 0 deletions
diff --git a/libraries/libldap_r/tpool.c b/libraries/libldap_r/tpool.c
new file mode 100644
index 0000000..17cee3b
--- /dev/null
+++ b/libraries/libldap_r/tpool.c
@@ -0,0 +1,1032 @@
+/* $OpenLDAP$ */
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ *
+ * Copyright 1998-2021 The OpenLDAP Foundation.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
+ */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/signal.h>
+#include <ac/stdarg.h>
+#include <ac/stdlib.h>
+#include <ac/string.h>
+#include <ac/time.h>
+#include <ac/errno.h>
+
+#include "ldap-int.h"
+#include "ldap_pvt_thread.h" /* Get the thread interface */
+#include "ldap_queue.h"
+#define LDAP_THREAD_POOL_IMPLEMENTATION
+#include "ldap_thr_debug.h" /* May rename symbols defined below */
+
+#ifndef LDAP_THREAD_HAVE_TPOOL
+
+/* Thread-specific key with data and optional free function */
+typedef struct ldap_int_tpool_key_s {
+ void *ltk_key;
+ void *ltk_data;
+ ldap_pvt_thread_pool_keyfree_t *ltk_free;
+} ldap_int_tpool_key_t;
+
+/* Max number of thread-specific keys we store per thread.
+ * We don't expect to use many...
+ */
+#define MAXKEYS 32
+
+/* Max number of threads */
+#define LDAP_MAXTHR 1024 /* must be a power of 2 */
+
+/* (Theoretical) max number of pending requests */
+#define MAX_PENDING (INT_MAX/2) /* INT_MAX - (room to avoid overflow) */
+
+/* pool->ltp_pause values */
+enum { NOT_PAUSED = 0, WANT_PAUSE = 1, PAUSED = 2 };
+
+/* Context: thread ID and thread-specific key/data pairs */
+typedef struct ldap_int_thread_userctx_s {
+ ldap_pvt_thread_t ltu_id;
+ ldap_int_tpool_key_t ltu_key[MAXKEYS];
+} ldap_int_thread_userctx_t;
+
+
+/* Simple {thread ID -> context} hash table; key=ctx->ltu_id.
+ * Protected by ldap_pvt_thread_pool_mutex except during pauses,
+ * when it is read-only (used by pool_purgekey and pool_context).
+ * Protected by tpool->ltp_mutex during pauses.
+ */
+static struct {
+ ldap_int_thread_userctx_t *ctx;
+ /* ctx is valid when not NULL or DELETED_THREAD_CTX */
+# define DELETED_THREAD_CTX (&ldap_int_main_thrctx + 1) /* dummy addr */
+} thread_keys[LDAP_MAXTHR];
+
+#define TID_HASH(tid, hash) do { \
+ unsigned const char *ptr_ = (unsigned const char *)&(tid); \
+ unsigned i_; \
+ for (i_ = 0, (hash) = ptr_[0]; ++i_ < sizeof(tid);) \
+ (hash) += ((hash) << 5) ^ ptr_[i_]; \
+} while(0)
+
+
+/* Task for a thread to perform */
+typedef struct ldap_int_thread_task_s {
+ union {
+ LDAP_STAILQ_ENTRY(ldap_int_thread_task_s) q;
+ LDAP_SLIST_ENTRY(ldap_int_thread_task_s) l;
+ } ltt_next;
+ ldap_pvt_thread_start_t *ltt_start_routine;
+ void *ltt_arg;
+} ldap_int_thread_task_t;
+
+typedef LDAP_STAILQ_HEAD(tcq, ldap_int_thread_task_s) ldap_int_tpool_plist_t;
+
+struct ldap_int_thread_pool_s {
+ LDAP_STAILQ_ENTRY(ldap_int_thread_pool_s) ltp_next;
+
+ /* protect members below, and protect thread_keys[] during pauses */
+ ldap_pvt_thread_mutex_t ltp_mutex;
+
+ /* not paused and something to do for pool_<wrapper/pause/destroy>() */
+ ldap_pvt_thread_cond_t ltp_cond;
+
+ /* ltp_active_count <= 1 && ltp_pause */
+ ldap_pvt_thread_cond_t ltp_pcond;
+
+ /* ltp_pause == 0 ? &ltp_pending_list : &empty_pending_list,
+ * maintaned to reduce work for pool_wrapper()
+ */
+ ldap_int_tpool_plist_t *ltp_work_list;
+
+ /* pending tasks, and unused task objects */
+ ldap_int_tpool_plist_t ltp_pending_list;
+ LDAP_SLIST_HEAD(tcl, ldap_int_thread_task_s) ltp_free_list;
+
+ /* The pool is finishing, waiting for its threads to close.
+ * They close when ltp_pending_list is done. pool_submit()
+ * rejects new tasks. ltp_max_pending = -(its old value).
+ */
+ int ltp_finishing;
+
+ /* Some active task needs to be the sole active task.
+ * Atomic variable so ldap_pvt_thread_pool_pausing() can read it.
+ * Note: Pauses adjust ltp_<open_count/vary_open_count/work_list>,
+ * so pool_<submit/wrapper>() mostly can avoid testing ltp_pause.
+ */
+ volatile sig_atomic_t ltp_pause;
+
+ /* Max number of threads in pool, or 0 for default (LDAP_MAXTHR) */
+ int ltp_max_count;
+
+ /* Max pending + paused + idle tasks, negated when ltp_finishing */
+ int ltp_max_pending;
+
+ int ltp_pending_count; /* Pending + paused + idle tasks */
+ int ltp_active_count; /* Active, not paused/idle tasks */
+ int ltp_open_count; /* Number of threads, negated when ltp_pause */
+ int ltp_starting; /* Currenlty starting threads */
+
+ /* >0 if paused or we may open a thread, <0 if we should close a thread.
+ * Updated when ltp_<finishing/pause/max_count/open_count> change.
+ * Maintained to reduce the time ltp_mutex must be locked in
+ * ldap_pvt_thread_pool_<submit/wrapper>().
+ */
+ int ltp_vary_open_count;
+# define SET_VARY_OPEN_COUNT(pool) \
+ ((pool)->ltp_vary_open_count = \
+ (pool)->ltp_pause ? 1 : \
+ (pool)->ltp_finishing ? -1 : \
+ ((pool)->ltp_max_count ? (pool)->ltp_max_count : LDAP_MAXTHR) \
+ - (pool)->ltp_open_count)
+};
+
+static ldap_int_tpool_plist_t empty_pending_list =
+ LDAP_STAILQ_HEAD_INITIALIZER(empty_pending_list);
+
+static int ldap_int_has_thread_pool = 0;
+static LDAP_STAILQ_HEAD(tpq, ldap_int_thread_pool_s)
+ ldap_int_thread_pool_list =
+ LDAP_STAILQ_HEAD_INITIALIZER(ldap_int_thread_pool_list);
+
+static ldap_pvt_thread_mutex_t ldap_pvt_thread_pool_mutex;
+
+static void *ldap_int_thread_pool_wrapper( void *pool );
+
+static ldap_pvt_thread_key_t ldap_tpool_key;
+
+/* Context of the main thread */
+static ldap_int_thread_userctx_t ldap_int_main_thrctx;
+
+int
+ldap_int_thread_pool_startup ( void )
+{
+ ldap_int_main_thrctx.ltu_id = ldap_pvt_thread_self();
+ ldap_pvt_thread_key_create( &ldap_tpool_key );
+ return ldap_pvt_thread_mutex_init(&ldap_pvt_thread_pool_mutex);
+}
+
+int
+ldap_int_thread_pool_shutdown ( void )
+{
+ struct ldap_int_thread_pool_s *pool;
+
+ while ((pool = LDAP_STAILQ_FIRST(&ldap_int_thread_pool_list)) != NULL) {
+ (ldap_pvt_thread_pool_destroy)(&pool, 0); /* ignore thr_debug macro */
+ }
+ ldap_pvt_thread_mutex_destroy(&ldap_pvt_thread_pool_mutex);
+ ldap_pvt_thread_key_destroy( ldap_tpool_key );
+ return(0);
+}
+
+
+/* Create a thread pool */
+int
+ldap_pvt_thread_pool_init (
+ ldap_pvt_thread_pool_t *tpool,
+ int max_threads,
+ int max_pending )
+{
+ ldap_pvt_thread_pool_t pool;
+ int rc;
+
+ /* multiple pools are currently not supported (ITS#4943) */
+ assert(!ldap_int_has_thread_pool);
+
+ if (! (0 <= max_threads && max_threads <= LDAP_MAXTHR))
+ max_threads = 0;
+ if (! (1 <= max_pending && max_pending <= MAX_PENDING))
+ max_pending = MAX_PENDING;
+
+ *tpool = NULL;
+ pool = (ldap_pvt_thread_pool_t) LDAP_CALLOC(1,
+ sizeof(struct ldap_int_thread_pool_s));
+
+ if (pool == NULL) return(-1);
+
+ rc = ldap_pvt_thread_mutex_init(&pool->ltp_mutex);
+ if (rc != 0) {
+fail1:
+ LDAP_FREE(pool);
+ return(rc);
+ }
+ rc = ldap_pvt_thread_cond_init(&pool->ltp_cond);
+ if (rc != 0) {
+fail2:
+ ldap_pvt_thread_mutex_destroy(&pool->ltp_mutex);
+ goto fail1;
+ }
+ rc = ldap_pvt_thread_cond_init(&pool->ltp_pcond);
+ if (rc != 0) {
+ ldap_pvt_thread_cond_destroy(&pool->ltp_cond);
+ goto fail2;
+ }
+
+ ldap_int_has_thread_pool = 1;
+
+ pool->ltp_max_count = max_threads;
+ SET_VARY_OPEN_COUNT(pool);
+ pool->ltp_max_pending = max_pending;
+
+ LDAP_STAILQ_INIT(&pool->ltp_pending_list);
+ pool->ltp_work_list = &pool->ltp_pending_list;
+ LDAP_SLIST_INIT(&pool->ltp_free_list);
+
+ ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
+ LDAP_STAILQ_INSERT_TAIL(&ldap_int_thread_pool_list, pool, ltp_next);
+ ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
+
+ /* Start no threads just yet. That can break if the process forks
+ * later, as slapd does in order to daemonize. On at least POSIX,
+ * only the forking thread would survive in the child. Yet fork()
+ * can't unlock/clean up other threads' locks and data structures,
+ * unless pthread_atfork() handlers have been set up to do so.
+ */
+
+ *tpool = pool;
+ return(0);
+}
+
+
+/* Submit a task to be performed by the thread pool */
+int
+ldap_pvt_thread_pool_submit (
+ ldap_pvt_thread_pool_t *tpool,
+ ldap_pvt_thread_start_t *start_routine, void *arg )
+{
+ struct ldap_int_thread_pool_s *pool;
+ ldap_int_thread_task_t *task;
+ ldap_pvt_thread_t thr;
+
+ if (tpool == NULL)
+ return(-1);
+
+ pool = *tpool;
+
+ if (pool == NULL)
+ return(-1);
+
+ ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
+
+ if (pool->ltp_pending_count >= pool->ltp_max_pending)
+ goto failed;
+
+ task = LDAP_SLIST_FIRST(&pool->ltp_free_list);
+ if (task) {
+ LDAP_SLIST_REMOVE_HEAD(&pool->ltp_free_list, ltt_next.l);
+ } else {
+ task = (ldap_int_thread_task_t *) LDAP_MALLOC(sizeof(*task));
+ if (task == NULL)
+ goto failed;
+ }
+
+ task->ltt_start_routine = start_routine;
+ task->ltt_arg = arg;
+
+ pool->ltp_pending_count++;
+ LDAP_STAILQ_INSERT_TAIL(&pool->ltp_pending_list, task, ltt_next.q);
+
+ /* true if ltp_pause != 0 or we should open (create) a thread */
+ if (pool->ltp_vary_open_count > 0 &&
+ pool->ltp_open_count < pool->ltp_active_count+pool->ltp_pending_count)
+ {
+ if (pool->ltp_pause)
+ goto done;
+
+ pool->ltp_starting++;
+ pool->ltp_open_count++;
+ SET_VARY_OPEN_COUNT(pool);
+
+ if (0 != ldap_pvt_thread_create(
+ &thr, 1, ldap_int_thread_pool_wrapper, pool))
+ {
+ /* couldn't create thread. back out of
+ * ltp_open_count and check for even worse things.
+ */
+ pool->ltp_starting--;
+ pool->ltp_open_count--;
+ SET_VARY_OPEN_COUNT(pool);
+
+ if (pool->ltp_open_count == 0) {
+ /* no open threads at all?!?
+ */
+ ldap_int_thread_task_t *ptr;
+
+ /* let pool_destroy know there are no more threads */
+ ldap_pvt_thread_cond_signal(&pool->ltp_cond);
+
+ LDAP_STAILQ_FOREACH(ptr, &pool->ltp_pending_list, ltt_next.q)
+ if (ptr == task) break;
+ if (ptr == task) {
+ /* no open threads, task not handled, so
+ * back out of ltp_pending_count, free the task,
+ * report the error.
+ */
+ pool->ltp_pending_count--;
+ LDAP_STAILQ_REMOVE(&pool->ltp_pending_list, task,
+ ldap_int_thread_task_s, ltt_next.q);
+ LDAP_SLIST_INSERT_HEAD(&pool->ltp_free_list, task,
+ ltt_next.l);
+ goto failed;
+ }
+ }
+ /* there is another open thread, so this
+ * task will be handled eventually.
+ */
+ }
+ }
+ ldap_pvt_thread_cond_signal(&pool->ltp_cond);
+
+ done:
+ ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
+ return(0);
+
+ failed:
+ ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
+ return(-1);
+}
+
+static void *
+no_task( void *ctx, void *arg )
+{
+ return NULL;
+}
+
+/* Cancel a pending task that was previously submitted.
+ * Return 1 if the task was successfully cancelled, 0 if
+ * not found, -1 for invalid parameters
+ */
+int
+ldap_pvt_thread_pool_retract (
+ ldap_pvt_thread_pool_t *tpool,
+ ldap_pvt_thread_start_t *start_routine, void *arg )
+{
+ struct ldap_int_thread_pool_s *pool;
+ ldap_int_thread_task_t *task;
+
+ if (tpool == NULL)
+ return(-1);
+
+ pool = *tpool;
+
+ if (pool == NULL)
+ return(-1);
+
+ ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
+ LDAP_STAILQ_FOREACH(task, &pool->ltp_pending_list, ltt_next.q)
+ if (task->ltt_start_routine == start_routine &&
+ task->ltt_arg == arg) {
+ /* Could LDAP_STAILQ_REMOVE the task, but that
+ * walks ltp_pending_list again to find it.
+ */
+ task->ltt_start_routine = no_task;
+ task->ltt_arg = NULL;
+ break;
+ }
+ ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
+ return task != NULL;
+}
+
+/* Set max #threads. value <= 0 means max supported #threads (LDAP_MAXTHR) */
+int
+ldap_pvt_thread_pool_maxthreads(
+ ldap_pvt_thread_pool_t *tpool,
+ int max_threads )
+{
+ struct ldap_int_thread_pool_s *pool;
+
+ if (! (0 <= max_threads && max_threads <= LDAP_MAXTHR))
+ max_threads = 0;
+
+ if (tpool == NULL)
+ return(-1);
+
+ pool = *tpool;
+
+ if (pool == NULL)
+ return(-1);
+
+ ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
+
+ pool->ltp_max_count = max_threads;
+ SET_VARY_OPEN_COUNT(pool);
+
+ ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
+ return(0);
+}
+
+/* Inspect the pool */
+int
+ldap_pvt_thread_pool_query(
+ ldap_pvt_thread_pool_t *tpool,
+ ldap_pvt_thread_pool_param_t param,
+ void *value )
+{
+ struct ldap_int_thread_pool_s *pool;
+ int count = -1;
+
+ if ( tpool == NULL || value == NULL ) {
+ return -1;
+ }
+
+ pool = *tpool;
+
+ if ( pool == NULL ) {
+ return 0;
+ }
+
+ ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
+ switch ( param ) {
+ case LDAP_PVT_THREAD_POOL_PARAM_MAX:
+ count = pool->ltp_max_count;
+ break;
+
+ case LDAP_PVT_THREAD_POOL_PARAM_MAX_PENDING:
+ count = pool->ltp_max_pending;
+ if (count < 0)
+ count = -count;
+ if (count == MAX_PENDING)
+ count = 0;
+ break;
+
+ case LDAP_PVT_THREAD_POOL_PARAM_OPEN:
+ count = pool->ltp_open_count;
+ if (count < 0)
+ count = -count;
+ break;
+
+ case LDAP_PVT_THREAD_POOL_PARAM_STARTING:
+ count = pool->ltp_starting;
+ break;
+
+ case LDAP_PVT_THREAD_POOL_PARAM_ACTIVE:
+ count = pool->ltp_active_count;
+ break;
+
+ case LDAP_PVT_THREAD_POOL_PARAM_PAUSING:
+ count = (pool->ltp_pause != 0);
+ break;
+
+ case LDAP_PVT_THREAD_POOL_PARAM_PENDING:
+ count = pool->ltp_pending_count;
+ break;
+
+ case LDAP_PVT_THREAD_POOL_PARAM_BACKLOAD:
+ count = pool->ltp_pending_count + pool->ltp_active_count;
+ break;
+
+ case LDAP_PVT_THREAD_POOL_PARAM_ACTIVE_MAX:
+ break;
+
+ case LDAP_PVT_THREAD_POOL_PARAM_PENDING_MAX:
+ break;
+
+ case LDAP_PVT_THREAD_POOL_PARAM_BACKLOAD_MAX:
+ break;
+
+ case LDAP_PVT_THREAD_POOL_PARAM_STATE:
+ *((char **)value) =
+ pool->ltp_pause ? "pausing" :
+ !pool->ltp_finishing ? "running" :
+ pool->ltp_pending_count ? "finishing" : "stopping";
+ break;
+
+ case LDAP_PVT_THREAD_POOL_PARAM_UNKNOWN:
+ break;
+ }
+ ldap_pvt_thread_mutex_unlock( &pool->ltp_mutex );
+
+ if ( count > -1 ) {
+ *((int *)value) = count;
+ }
+
+ return ( count == -1 ? -1 : 0 );
+}
+
+/*
+ * true if pool is pausing; does not lock any mutex to check.
+ * 0 if not pause, 1 if pause, -1 if error or no pool.
+ */
+int
+ldap_pvt_thread_pool_pausing( ldap_pvt_thread_pool_t *tpool )
+{
+ int rc = -1;
+ struct ldap_int_thread_pool_s *pool;
+
+ if ( tpool != NULL && (pool = *tpool) != NULL ) {
+ rc = (pool->ltp_pause != 0);
+ }
+
+ return rc;
+}
+
+/*
+ * wrapper for ldap_pvt_thread_pool_query(), left around
+ * for backwards compatibility
+ */
+int
+ldap_pvt_thread_pool_backload ( ldap_pvt_thread_pool_t *tpool )
+{
+ int rc, count;
+
+ rc = ldap_pvt_thread_pool_query( tpool,
+ LDAP_PVT_THREAD_POOL_PARAM_BACKLOAD, (void *)&count );
+
+ if ( rc == 0 ) {
+ return count;
+ }
+
+ return rc;
+}
+
+/* Destroy the pool after making its threads finish */
+int
+ldap_pvt_thread_pool_destroy ( ldap_pvt_thread_pool_t *tpool, int run_pending )
+{
+ struct ldap_int_thread_pool_s *pool, *pptr;
+ ldap_int_thread_task_t *task;
+
+ if (tpool == NULL)
+ return(-1);
+
+ pool = *tpool;
+
+ if (pool == NULL) return(-1);
+
+ ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
+ LDAP_STAILQ_FOREACH(pptr, &ldap_int_thread_pool_list, ltp_next)
+ if (pptr == pool) break;
+ if (pptr == pool)
+ LDAP_STAILQ_REMOVE(&ldap_int_thread_pool_list, pool,
+ ldap_int_thread_pool_s, ltp_next);
+ ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
+
+ if (pool != pptr) return(-1);
+
+ ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
+
+ pool->ltp_finishing = 1;
+ SET_VARY_OPEN_COUNT(pool);
+ if (pool->ltp_max_pending > 0)
+ pool->ltp_max_pending = -pool->ltp_max_pending;
+
+ if (!run_pending) {
+ while ((task = LDAP_STAILQ_FIRST(&pool->ltp_pending_list)) != NULL) {
+ LDAP_STAILQ_REMOVE_HEAD(&pool->ltp_pending_list, ltt_next.q);
+ LDAP_FREE(task);
+ }
+ pool->ltp_pending_count = 0;
+ }
+
+ while (pool->ltp_open_count) {
+ if (!pool->ltp_pause)
+ ldap_pvt_thread_cond_broadcast(&pool->ltp_cond);
+ ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
+ }
+
+ while ((task = LDAP_SLIST_FIRST(&pool->ltp_free_list)) != NULL)
+ {
+ LDAP_SLIST_REMOVE_HEAD(&pool->ltp_free_list, ltt_next.l);
+ LDAP_FREE(task);
+ }
+
+ ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
+ ldap_pvt_thread_cond_destroy(&pool->ltp_pcond);
+ ldap_pvt_thread_cond_destroy(&pool->ltp_cond);
+ ldap_pvt_thread_mutex_destroy(&pool->ltp_mutex);
+ LDAP_FREE(pool);
+ *tpool = NULL;
+ ldap_int_has_thread_pool = 0;
+ return(0);
+}
+
+/* Thread loop. Accept and handle submitted tasks. */
+static void *
+ldap_int_thread_pool_wrapper (
+ void *xpool )
+{
+ struct ldap_int_thread_pool_s *pool = xpool;
+ ldap_int_thread_task_t *task;
+ ldap_int_tpool_plist_t *work_list;
+ ldap_int_thread_userctx_t ctx, *kctx;
+ unsigned i, keyslot, hash;
+
+ assert(pool != NULL);
+
+ for ( i=0; i<MAXKEYS; i++ ) {
+ ctx.ltu_key[i].ltk_key = NULL;
+ }
+
+ ctx.ltu_id = ldap_pvt_thread_self();
+ TID_HASH(ctx.ltu_id, hash);
+
+ ldap_pvt_thread_key_setdata( ldap_tpool_key, &ctx );
+
+ ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
+
+ /* thread_keys[] is read-only when paused */
+ while (pool->ltp_pause)
+ ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
+
+ /* find a key slot to give this thread ID and store a
+ * pointer to our keys there; start at the thread ID
+ * itself (mod LDAP_MAXTHR) and look for an empty slot.
+ */
+ ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
+ for (keyslot = hash & (LDAP_MAXTHR-1);
+ (kctx = thread_keys[keyslot].ctx) && kctx != DELETED_THREAD_CTX;
+ keyslot = (keyslot+1) & (LDAP_MAXTHR-1));
+ thread_keys[keyslot].ctx = &ctx;
+ ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
+
+ pool->ltp_starting--;
+ pool->ltp_active_count++;
+
+ for (;;) {
+ work_list = pool->ltp_work_list; /* help the compiler a bit */
+ task = LDAP_STAILQ_FIRST(work_list);
+ if (task == NULL) { /* paused or no pending tasks */
+ if (--(pool->ltp_active_count) < 2) {
+ /* Notify pool_pause it is the sole active thread. */
+ ldap_pvt_thread_cond_signal(&pool->ltp_pcond);
+ }
+
+ do {
+ if (pool->ltp_vary_open_count < 0) {
+ /* Not paused, and either finishing or too many
+ * threads running (can happen if ltp_max_count
+ * was reduced). Let this thread die.
+ */
+ goto done;
+ }
+
+ /* We could check an idle timer here, and let the
+ * thread die if it has been inactive for a while.
+ * Only die if there are other open threads (i.e.,
+ * always have at least one thread open).
+ * The check should be like this:
+ * if (pool->ltp_open_count>1 && pool->ltp_starting==0)
+ * check timer, wait if ltp_pause, leave thread;
+ *
+ * Just use pthread_cond_timedwait() if we want to
+ * check idle time.
+ */
+ ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
+
+ work_list = pool->ltp_work_list;
+ task = LDAP_STAILQ_FIRST(work_list);
+ } while (task == NULL);
+
+ pool->ltp_active_count++;
+ }
+
+ LDAP_STAILQ_REMOVE_HEAD(work_list, ltt_next.q);
+ pool->ltp_pending_count--;
+ ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
+
+ task->ltt_start_routine(&ctx, task->ltt_arg);
+
+ ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
+ LDAP_SLIST_INSERT_HEAD(&pool->ltp_free_list, task, ltt_next.l);
+ }
+ done:
+
+ assert(!pool->ltp_pause); /* thread_keys writable, ltp_open_count >= 0 */
+
+ /* The ltp_mutex lock protects ctx->ltu_key from pool_purgekey()
+ * during this call, since it prevents new pauses. */
+ ldap_pvt_thread_pool_context_reset(&ctx);
+
+ ldap_pvt_thread_mutex_lock(&ldap_pvt_thread_pool_mutex);
+ thread_keys[keyslot].ctx = DELETED_THREAD_CTX;
+ ldap_pvt_thread_mutex_unlock(&ldap_pvt_thread_pool_mutex);
+
+ pool->ltp_open_count--;
+ SET_VARY_OPEN_COUNT(pool);
+ /* let pool_destroy know we're all done */
+ if (pool->ltp_open_count == 0)
+ ldap_pvt_thread_cond_signal(&pool->ltp_cond);
+
+ ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
+
+ ldap_pvt_thread_exit(NULL);
+ return(NULL);
+}
+
+/* Arguments > ltp_pause to handle_pause(,PAUSE_ARG()). arg=PAUSE_ARG
+ * ensures (arg-ltp_pause) sets GO_* at need and keeps DO_PAUSE/GO_*.
+ */
+#define GO_IDLE 8
+#define GO_UNIDLE 16
+#define CHECK_PAUSE 32 /* if ltp_pause: GO_IDLE; wait; GO_UNIDLE */
+#define DO_PAUSE 64 /* CHECK_PAUSE; pause the pool */
+#define PAUSE_ARG(a) \
+ ((a) | ((a) & (GO_IDLE|GO_UNIDLE) ? GO_IDLE-1 : CHECK_PAUSE))
+
+static int
+handle_pause( ldap_pvt_thread_pool_t *tpool, int pause_type )
+{
+ struct ldap_int_thread_pool_s *pool;
+ int ret = 0, pause, max_ltp_pause;
+
+ if (tpool == NULL)
+ return(-1);
+
+ pool = *tpool;
+
+ if (pool == NULL)
+ return(0);
+
+ if (pause_type == CHECK_PAUSE && !pool->ltp_pause)
+ return(0);
+
+ /* Let pool_unidle() ignore requests for new pauses */
+ max_ltp_pause = pause_type==PAUSE_ARG(GO_UNIDLE) ? WANT_PAUSE : NOT_PAUSED;
+
+ ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
+
+ pause = pool->ltp_pause; /* NOT_PAUSED, WANT_PAUSE or PAUSED */
+
+ /* If ltp_pause and not GO_IDLE|GO_UNIDLE: Set GO_IDLE,GO_UNIDLE */
+ pause_type -= pause;
+
+ if (pause_type & GO_IDLE) {
+ pool->ltp_pending_count++;
+ pool->ltp_active_count--;
+ if (pause && pool->ltp_active_count < 2) {
+ /* Tell the task waiting to DO_PAUSE it can proceed */
+ ldap_pvt_thread_cond_signal(&pool->ltp_pcond);
+ }
+ }
+
+ if (pause_type & GO_UNIDLE) {
+ /* Wait out pause if any, then cancel GO_IDLE */
+ if (pause > max_ltp_pause) {
+ ret = 1;
+ do {
+ ldap_pvt_thread_cond_wait(&pool->ltp_cond, &pool->ltp_mutex);
+ } while (pool->ltp_pause > max_ltp_pause);
+ }
+ pool->ltp_pending_count--;
+ pool->ltp_active_count++;
+ }
+
+ if (pause_type & DO_PAUSE) {
+ /* Tell everyone else to pause or finish, then await that */
+ ret = 0;
+ assert(!pool->ltp_pause);
+ pool->ltp_pause = WANT_PAUSE;
+ /* Let ldap_pvt_thread_pool_submit() through to its ltp_pause test,
+ * and do not finish threads in ldap_pvt_thread_pool_wrapper() */
+ pool->ltp_open_count = -pool->ltp_open_count;
+ SET_VARY_OPEN_COUNT(pool);
+ /* Hide pending tasks from ldap_pvt_thread_pool_wrapper() */
+ pool->ltp_work_list = &empty_pending_list;
+ /* Wait for this task to become the sole active task */
+ while (pool->ltp_active_count > 1) {
+ ldap_pvt_thread_cond_wait(&pool->ltp_pcond, &pool->ltp_mutex);
+ }
+ assert(pool->ltp_pause == WANT_PAUSE);
+ pool->ltp_pause = PAUSED;
+ }
+
+ ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
+ return(ret);
+}
+
+/* Consider this task idle: It will not block pool_pause() in other tasks. */
+void
+ldap_pvt_thread_pool_idle( ldap_pvt_thread_pool_t *tpool )
+{
+ handle_pause(tpool, PAUSE_ARG(GO_IDLE));
+}
+
+/* Cancel pool_idle(). If the pool is paused, wait it out first. */
+void
+ldap_pvt_thread_pool_unidle( ldap_pvt_thread_pool_t *tpool )
+{
+ handle_pause(tpool, PAUSE_ARG(GO_UNIDLE));
+}
+
+/*
+ * If a pause was requested, wait for it. If several threads
+ * are waiting to pause, let through one or more pauses.
+ * The calling task must be active, not idle.
+ * Return 1 if we waited, 0 if not, -1 at parameter error.
+ */
+int
+ldap_pvt_thread_pool_pausecheck( ldap_pvt_thread_pool_t *tpool )
+{
+ return handle_pause(tpool, PAUSE_ARG(CHECK_PAUSE));
+}
+
+/*
+ * Pause the pool. The calling task must be active, not idle.
+ * Return when all other tasks are paused or idle.
+ */
+int
+ldap_pvt_thread_pool_pause( ldap_pvt_thread_pool_t *tpool )
+{
+ return handle_pause(tpool, PAUSE_ARG(DO_PAUSE));
+}
+
+/* End a pause */
+int
+ldap_pvt_thread_pool_resume (
+ ldap_pvt_thread_pool_t *tpool )
+{
+ struct ldap_int_thread_pool_s *pool;
+
+ if (tpool == NULL)
+ return(-1);
+
+ pool = *tpool;
+
+ if (pool == NULL)
+ return(0);
+
+ ldap_pvt_thread_mutex_lock(&pool->ltp_mutex);
+
+ assert(pool->ltp_pause == PAUSED);
+ pool->ltp_pause = 0;
+ if (pool->ltp_open_count <= 0) /* true when paused, but be paranoid */
+ pool->ltp_open_count = -pool->ltp_open_count;
+ SET_VARY_OPEN_COUNT(pool);
+ pool->ltp_work_list = &pool->ltp_pending_list;
+
+ ldap_pvt_thread_cond_broadcast(&pool->ltp_cond);
+
+ ldap_pvt_thread_mutex_unlock(&pool->ltp_mutex);
+ return(0);
+}
+
+/*
+ * Get the key's data and optionally free function in the given context.
+ */
+int ldap_pvt_thread_pool_getkey(
+ void *xctx,
+ void *key,
+ void **data,
+ ldap_pvt_thread_pool_keyfree_t **kfree )
+{
+ ldap_int_thread_userctx_t *ctx = xctx;
+ int i;
+
+ if ( !ctx || !key || !data ) return EINVAL;
+
+ for ( i=0; i<MAXKEYS && ctx->ltu_key[i].ltk_key; i++ ) {
+ if ( ctx->ltu_key[i].ltk_key == key ) {
+ *data = ctx->ltu_key[i].ltk_data;
+ if ( kfree ) *kfree = ctx->ltu_key[i].ltk_free;
+ return 0;
+ }
+ }
+ return ENOENT;
+}
+
+static void
+clear_key_idx( ldap_int_thread_userctx_t *ctx, int i )
+{
+ for ( ; i < MAXKEYS-1 && ctx->ltu_key[i+1].ltk_key; i++ )
+ ctx->ltu_key[i] = ctx->ltu_key[i+1];
+ ctx->ltu_key[i].ltk_key = NULL;
+}
+
+/*
+ * Set or remove data for the key in the given context.
+ * key can be any unique pointer.
+ * kfree() is an optional function to free the data (but not the key):
+ * pool_context_reset() and pool_purgekey() call kfree(key, data),
+ * but pool_setkey() does not. For pool_setkey() it is the caller's
+ * responsibility to free any existing data with the same key.
+ * kfree() must not call functions taking a tpool argument.
+ */
+int ldap_pvt_thread_pool_setkey(
+ void *xctx,
+ void *key,
+ void *data,
+ ldap_pvt_thread_pool_keyfree_t *kfree,
+ void **olddatap,
+ ldap_pvt_thread_pool_keyfree_t **oldkfreep )
+{
+ ldap_int_thread_userctx_t *ctx = xctx;
+ int i, found;
+
+ if ( !ctx || !key ) return EINVAL;
+
+ for ( i=found=0; i<MAXKEYS; i++ ) {
+ if ( ctx->ltu_key[i].ltk_key == key ) {
+ found = 1;
+ break;
+ } else if ( !ctx->ltu_key[i].ltk_key ) {
+ break;
+ }
+ }
+
+ if ( olddatap ) {
+ if ( found ) {
+ *olddatap = ctx->ltu_key[i].ltk_data;
+ } else {
+ *olddatap = NULL;
+ }
+ }
+
+ if ( oldkfreep ) {
+ if ( found ) {
+ *oldkfreep = ctx->ltu_key[i].ltk_free;
+ } else {
+ *oldkfreep = 0;
+ }
+ }
+
+ if ( data || kfree ) {
+ if ( i>=MAXKEYS )
+ return ENOMEM;
+ ctx->ltu_key[i].ltk_key = key;
+ ctx->ltu_key[i].ltk_data = data;
+ ctx->ltu_key[i].ltk_free = kfree;
+ } else if ( found ) {
+ clear_key_idx( ctx, i );
+ }
+
+ return 0;
+}
+
+/* Free all elements with this key, no matter which thread they're in.
+ * May only be called while the pool is paused.
+ */
+void ldap_pvt_thread_pool_purgekey( void *key )
+{
+ int i, j;
+ ldap_int_thread_userctx_t *ctx;
+
+ assert ( key != NULL );
+
+ for ( i=0; i<LDAP_MAXTHR; i++ ) {
+ ctx = thread_keys[i].ctx;
+ if ( ctx && ctx != DELETED_THREAD_CTX ) {
+ for ( j=0; j<MAXKEYS && ctx->ltu_key[j].ltk_key; j++ ) {
+ if ( ctx->ltu_key[j].ltk_key == key ) {
+ if (ctx->ltu_key[j].ltk_free)
+ ctx->ltu_key[j].ltk_free( ctx->ltu_key[j].ltk_key,
+ ctx->ltu_key[j].ltk_data );
+ clear_key_idx( ctx, j );
+ break;
+ }
+ }
+ }
+ }
+}
+
+/*
+ * Find the context of the current thread.
+ * This is necessary if the caller does not have access to the
+ * thread context handle (for example, a slapd plugin calling
+ * slapi_search_internal()). No doubt it is more efficient
+ * for the application to keep track of the thread context
+ * handles itself.
+ */
+void *ldap_pvt_thread_pool_context( )
+{
+ void *ctx = NULL;
+
+ ldap_pvt_thread_key_getdata( ldap_tpool_key, &ctx );
+ return ctx ? ctx : (void *) &ldap_int_main_thrctx;
+}
+
+/*
+ * Free the context's keys.
+ * Must not call functions taking a tpool argument (because this
+ * thread already holds ltp_mutex when called from pool_wrapper()).
+ */
+void ldap_pvt_thread_pool_context_reset( void *vctx )
+{
+ ldap_int_thread_userctx_t *ctx = vctx;
+ int i;
+
+ for ( i=MAXKEYS-1; i>=0; i--) {
+ if ( !ctx->ltu_key[i].ltk_key )
+ continue;
+ if ( ctx->ltu_key[i].ltk_free )
+ ctx->ltu_key[i].ltk_free( ctx->ltu_key[i].ltk_key,
+ ctx->ltu_key[i].ltk_data );
+ ctx->ltu_key[i].ltk_key = NULL;
+ }
+}
+
+ldap_pvt_thread_t ldap_pvt_thread_pool_tid( void *vctx )
+{
+ ldap_int_thread_userctx_t *ctx = vctx;
+
+ return ctx->ltu_id;
+}
+#endif /* LDAP_THREAD_HAVE_TPOOL */