+++ /dev/null
-/* Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include "fdqueue.h"
-#include "apr_atomic.h"
-
-typedef struct recycled_pool {
- apr_pool_t *pool;
- struct recycled_pool *next;
-} recycled_pool;
-
-struct fd_queue_info_t {
- volatile apr_uint32_t idlers;
- apr_thread_mutex_t *idlers_mutex;
- apr_thread_cond_t *wait_for_idler;
- int terminated;
- int max_idlers;
- recycled_pool *recycled_pools;
-};
-
-static apr_status_t queue_info_cleanup(void *data_)
-{
- fd_queue_info_t *qi = data_;
- apr_thread_cond_destroy(qi->wait_for_idler);
- apr_thread_mutex_destroy(qi->idlers_mutex);
-
- /* Clean up any pools in the recycled list */
- for (;;) {
- struct recycled_pool *first_pool = qi->recycled_pools;
- if (first_pool == NULL) {
- break;
- }
- if (apr_atomic_casptr((void*)&(qi->recycled_pools), first_pool->next,
- first_pool) == first_pool) {
- apr_pool_destroy(first_pool->pool);
- }
- }
-
- return APR_SUCCESS;
-}
-
-apr_status_t ap_queue_info_create(fd_queue_info_t **queue_info,
- apr_pool_t *pool, int max_idlers)
-{
- apr_status_t rv;
- fd_queue_info_t *qi;
-
- qi = apr_pcalloc(pool, sizeof(*qi));
-
- rv = apr_thread_mutex_create(&qi->idlers_mutex, APR_THREAD_MUTEX_DEFAULT,
- pool);
- if (rv != APR_SUCCESS) {
- return rv;
- }
- rv = apr_thread_cond_create(&qi->wait_for_idler, pool);
- if (rv != APR_SUCCESS) {
- return rv;
- }
- qi->recycled_pools = NULL;
- qi->max_idlers = max_idlers;
- apr_pool_cleanup_register(pool, qi, queue_info_cleanup,
- apr_pool_cleanup_null);
-
- *queue_info = qi;
-
- return APR_SUCCESS;
-}
-
-apr_status_t ap_queue_info_set_idle(fd_queue_info_t *queue_info,
- apr_pool_t *pool_to_recycle)
-{
- apr_status_t rv;
-
- /* If we have been given a pool to recycle, atomically link
- * it into the queue_info's list of recycled pools
- */
- if (pool_to_recycle) {
- struct recycled_pool *new_recycle;
- new_recycle = (struct recycled_pool *)apr_palloc(pool_to_recycle,
- sizeof(*new_recycle));
- new_recycle->pool = pool_to_recycle;
- for (;;) {
- /* Save queue_info->recycled_pool in local variable next because
- * new_recycle->next can be changed after apr_atomic_casptr
- * function call. For gory details see PR 44402.
- */
- struct recycled_pool *next = queue_info->recycled_pools;
- new_recycle->next = next;
- if (apr_atomic_casptr((void*)&(queue_info->recycled_pools),
- new_recycle, next) == next) {
- break;
- }
- }
- }
-
- /* If this thread makes the idle worker count nonzero,
- * wake up the listener. */
- if (apr_atomic_inc32(&queue_info->idlers) == 0) {
- rv = apr_thread_mutex_lock(queue_info->idlers_mutex);
- if (rv != APR_SUCCESS) {
- return rv;
- }
- rv = apr_thread_cond_signal(queue_info->wait_for_idler);
- if (rv != APR_SUCCESS) {
- apr_thread_mutex_unlock(queue_info->idlers_mutex);
- return rv;
- }
- rv = apr_thread_mutex_unlock(queue_info->idlers_mutex);
- if (rv != APR_SUCCESS) {
- return rv;
- }
- }
-
- return APR_SUCCESS;
-}
-
-apr_status_t ap_queue_info_wait_for_idler(fd_queue_info_t *queue_info,
- apr_pool_t **recycled_pool)
-{
- apr_status_t rv;
-
- *recycled_pool = NULL;
-
- /* Block if the count of idle workers is zero */
- if (queue_info->idlers == 0) {
- rv = apr_thread_mutex_lock(queue_info->idlers_mutex);
- if (rv != APR_SUCCESS) {
- return rv;
- }
- /* Re-check the idle worker count to guard against a
- * race condition. Now that we're in the mutex-protected
- * region, one of two things may have happened:
- * - If the idle worker count is still zero, the
- * workers are all still busy, so it's safe to
- * block on a condition variable, BUT
- * we need to check for idle worker count again
- * when we are signaled since it can happen that
- * we are signaled by a worker thread that went idle
- * but received a context switch before it could
- * tell us. If it does signal us later once it is on
- * CPU again there might be no idle worker left.
- * See
- * https://issues.apache.org/bugzilla/show_bug.cgi?id=45605#c4
- * - If the idle worker count is nonzero, then a
- * worker has become idle since the first check
- * of queue_info->idlers above. It's possible
- * that the worker has also signaled the condition
- * variable--and if so, the listener missed it
- * because it wasn't yet blocked on the condition
- * variable. But if the idle worker count is
- * now nonzero, it's safe for this function to
- * return immediately.
- */
- while (queue_info->idlers == 0) {
- rv = apr_thread_cond_wait(queue_info->wait_for_idler,
- queue_info->idlers_mutex);
- if (rv != APR_SUCCESS) {
- apr_status_t rv2;
- rv2 = apr_thread_mutex_unlock(queue_info->idlers_mutex);
- if (rv2 != APR_SUCCESS) {
- return rv2;
- }
- return rv;
- }
- }
- rv = apr_thread_mutex_unlock(queue_info->idlers_mutex);
- if (rv != APR_SUCCESS) {
- return rv;
- }
- }
-
- /* Atomically decrement the idle worker count */
- apr_atomic_dec32(&(queue_info->idlers));
-
- /* Atomically pop a pool from the recycled list */
-
- /* This function is safe only as long as it is single threaded because
- * it reaches into the queue and accesses "next" which can change.
- * We are OK today because it is only called from the listener thread.
- * cas-based pushes do not have the same limitation - any number can
- * happen concurrently with a single cas-based pop.
- */
-
- for (;;) {
- struct recycled_pool *first_pool = queue_info->recycled_pools;
- if (first_pool == NULL) {
- break;
- }
- if (apr_atomic_casptr((void*)&(queue_info->recycled_pools), first_pool->next,
- first_pool) == first_pool) {
- *recycled_pool = first_pool->pool;
- break;
- }
- }
-
- if (queue_info->terminated) {
- return APR_EOF;
- }
- else {
- return APR_SUCCESS;
- }
-}
-
-apr_status_t ap_queue_info_term(fd_queue_info_t *queue_info)
-{
- apr_status_t rv;
- rv = apr_thread_mutex_lock(queue_info->idlers_mutex);
- if (rv != APR_SUCCESS) {
- return rv;
- }
- queue_info->terminated = 1;
- apr_thread_cond_broadcast(queue_info->wait_for_idler);
- return apr_thread_mutex_unlock(queue_info->idlers_mutex);
-}
-
-/**
- * Detects when the fd_queue_t is full. This utility function is expected
- * to be called from within critical sections, and is not threadsafe.
- */
-#define ap_queue_full(queue) ((queue)->nelts == (queue)->bounds)
-
-/**
- * Detects when the fd_queue_t is empty. This utility function is expected
- * to be called from within critical sections, and is not threadsafe.
- */
-#define ap_queue_empty(queue) ((queue)->nelts == 0)
-
-/**
- * Callback routine that is called to destroy this
- * fd_queue_t when its pool is destroyed.
- */
-static apr_status_t ap_queue_destroy(void *data)
-{
- fd_queue_t *queue = data;
-
- /* Ignore errors here, we can't do anything about them anyway.
- * XXX: We should at least try to signal an error here, it is
- * indicative of a programmer error. -aaron */
- apr_thread_cond_destroy(queue->not_empty);
- apr_thread_mutex_destroy(queue->one_big_mutex);
-
- return APR_SUCCESS;
-}
-
-/**
- * Initialize the fd_queue_t.
- */
-apr_status_t ap_queue_init(fd_queue_t *queue, int queue_capacity, apr_pool_t *a)
-{
- int i;
- apr_status_t rv;
-
- if ((rv = apr_thread_mutex_create(&queue->one_big_mutex,
- APR_THREAD_MUTEX_DEFAULT, a)) != APR_SUCCESS) {
- return rv;
- }
- if ((rv = apr_thread_cond_create(&queue->not_empty, a)) != APR_SUCCESS) {
- return rv;
- }
-
- queue->data = apr_palloc(a, queue_capacity * sizeof(fd_queue_elem_t));
- queue->bounds = queue_capacity;
- queue->nelts = 0;
- queue->in = 0;
- queue->out = 0;
-
- /* Set all the sockets in the queue to NULL */
- for (i = 0; i < queue_capacity; ++i)
- queue->data[i].sd = NULL;
-
- apr_pool_cleanup_register(a, queue, ap_queue_destroy, apr_pool_cleanup_null);
-
- return APR_SUCCESS;
-}
-
-/**
- * Push a new socket onto the queue.
- *
- * precondition: ap_queue_info_wait_for_idler has already been called
- * to reserve an idle worker thread
- */
-apr_status_t ap_queue_push(fd_queue_t *queue, apr_socket_t *sd, apr_pool_t *p)
-{
- fd_queue_elem_t *elem;
- apr_status_t rv;
-
- if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
- return rv;
- }
-
- AP_DEBUG_ASSERT(!queue->terminated);
- AP_DEBUG_ASSERT(!ap_queue_full(queue));
-
- elem = &queue->data[queue->in];
- queue->in++;
- if (queue->in >= queue->bounds)
- queue->in -= queue->bounds;
- elem->sd = sd;
- elem->p = p;
- queue->nelts++;
-
- apr_thread_cond_signal(queue->not_empty);
-
- if ((rv = apr_thread_mutex_unlock(queue->one_big_mutex)) != APR_SUCCESS) {
- return rv;
- }
-
- return APR_SUCCESS;
-}
-
-/**
- * Retrieves the next available socket from the queue. If there are no
- * sockets available, it will block until one becomes available.
- * Once retrieved, the socket is placed into the address specified by
- * 'sd'.
- */
-apr_status_t ap_queue_pop(fd_queue_t *queue, apr_socket_t **sd, apr_pool_t **p)
-{
- fd_queue_elem_t *elem;
- apr_status_t rv;
-
- if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
- return rv;
- }
-
- /* Keep waiting until we wake up and find that the queue is not empty. */
- if (ap_queue_empty(queue)) {
- if (!queue->terminated) {
- apr_thread_cond_wait(queue->not_empty, queue->one_big_mutex);
- }
- /* If we wake up and it's still empty, then we were interrupted */
- if (ap_queue_empty(queue)) {
- rv = apr_thread_mutex_unlock(queue->one_big_mutex);
- if (rv != APR_SUCCESS) {
- return rv;
- }
- if (queue->terminated) {
- return APR_EOF; /* no more elements ever again */
- }
- else {
- return APR_EINTR;
- }
- }
- }
-
- elem = &queue->data[queue->out];
- queue->out++;
- if (queue->out >= queue->bounds)
- queue->out -= queue->bounds;
- queue->nelts--;
- *sd = elem->sd;
- *p = elem->p;
-#ifdef AP_DEBUG
- elem->sd = NULL;
- elem->p = NULL;
-#endif /* AP_DEBUG */
-
- rv = apr_thread_mutex_unlock(queue->one_big_mutex);
- return rv;
-}
-
-static apr_status_t queue_interrupt_all(fd_queue_t *queue, int term)
-{
- apr_status_t rv;
-
- if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
- return rv;
- }
- /* we must hold one_big_mutex when setting this... otherwise,
- * we could end up setting it and waking everybody up just after a
- * would-be popper checks it but right before they block
- */
- if (term) {
- queue->terminated = 1;
- }
- apr_thread_cond_broadcast(queue->not_empty);
- return apr_thread_mutex_unlock(queue->one_big_mutex);
-}
-
-apr_status_t ap_queue_interrupt_all(fd_queue_t *queue)
-{
- return queue_interrupt_all(queue, 0);
-}
-
-apr_status_t ap_queue_term(fd_queue_t *queue)
-{
- return queue_interrupt_all(queue, 1);
-}
+++ /dev/null
-/* Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-/**
- * @file worker/fdqueue.h
- * @brief fd queue declarations
- *
- * @addtogroup APACHE_MPM_WORKER
- * @{
- */
-
-#ifndef FDQUEUE_H
-#define FDQUEUE_H
-#include "httpd.h"
-#include <stdlib.h>
-#if APR_HAVE_UNISTD_H
-#include <unistd.h>
-#endif
-#include <apr_thread_mutex.h>
-#include <apr_thread_cond.h>
-#include <sys/types.h>
-#if APR_HAVE_SYS_SOCKET_H
-#include <sys/socket.h>
-#endif
-#include <apr_errno.h>
-
-typedef struct fd_queue_info_t fd_queue_info_t;
-
-apr_status_t ap_queue_info_create(fd_queue_info_t **queue_info,
- apr_pool_t *pool, int max_idlers);
-apr_status_t ap_queue_info_set_idle(fd_queue_info_t *queue_info,
- apr_pool_t *pool_to_recycle);
-apr_status_t ap_queue_info_wait_for_idler(fd_queue_info_t *queue_info,
- apr_pool_t **recycled_pool);
-apr_status_t ap_queue_info_term(fd_queue_info_t *queue_info);
-
-struct fd_queue_elem_t {
- apr_socket_t *sd;
- apr_pool_t *p;
-};
-typedef struct fd_queue_elem_t fd_queue_elem_t;
-
-struct fd_queue_t {
- fd_queue_elem_t *data;
- unsigned int nelts;
- unsigned int bounds;
- unsigned int in;
- unsigned int out;
- apr_thread_mutex_t *one_big_mutex;
- apr_thread_cond_t *not_empty;
- int terminated;
-};
-typedef struct fd_queue_t fd_queue_t;
-
-apr_status_t ap_queue_init(fd_queue_t *queue, int queue_capacity, apr_pool_t *a);
-apr_status_t ap_queue_push(fd_queue_t *queue, apr_socket_t *sd, apr_pool_t *p);
-apr_status_t ap_queue_pop(fd_queue_t *queue, apr_socket_t **sd, apr_pool_t **p);
-apr_status_t ap_queue_interrupt_all(fd_queue_t *queue);
-apr_status_t ap_queue_term(fd_queue_t *queue);
-
-#endif /* FDQUEUE_H */
-/** @} */
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