+++ /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.
- */
-
-/*
- * Rules for managing obj->refcount:
- * refcount should be incremented when an object is placed in the cache. Insertion
- * of an object into the cache and the refcount increment should happen under
- * protection of the sconf->lock.
- *
- * refcount should be decremented when the object is removed from the cache.
- * Object should be removed from the cache and the refcount decremented while
- * under protection of the sconf->lock.
- *
- * refcount should be incremented when an object is retrieved from the cache
- * by a worker thread. The retrieval/find operation and refcount increment
- * should occur under protection of the sconf->lock
- *
- * refcount can be atomically decremented w/o protection of the sconf->lock
- * by worker threads.
- *
- * Any object whose refcount drops to 0 should be freed/cleaned up. A refcount
- * of 0 means the object is not in the cache and no worker threads are accessing
- * it.
- */
-#include "mod_cache.h"
-#include "cache_pqueue.h"
-#include "cache_cache.h"
-#include "ap_provider.h"
-#include "ap_mpm.h"
-#include "apr_thread_mutex.h"
-#if APR_HAVE_UNISTD_H
-#include <unistd.h>
-#endif
-
-#if !APR_HAS_THREADS
-#error This module does not currently compile unless you have a thread-capable APR. Sorry!
-#endif
-
-module AP_MODULE_DECLARE_DATA mem_cache_module;
-
-typedef enum {
- CACHE_TYPE_FILE = 1,
- CACHE_TYPE_HEAP,
- CACHE_TYPE_MMAP
-} cache_type_e;
-
-typedef struct mem_cache_object {
- apr_pool_t *pool;
- cache_type_e type;
- apr_table_t *header_out;
- apr_table_t *req_hdrs; /* for Vary negotiation */
- apr_size_t m_len;
- void *m;
- apr_os_file_t fd;
- apr_int32_t flags; /* File open flags */
- long priority; /**< the priority of this entry */
- long total_refs; /**< total number of references this entry has had */
-
- apr_uint32_t pos; /**< the position of this entry in the cache */
-
-} mem_cache_object_t;
-
-typedef struct {
- apr_thread_mutex_t *lock;
- cache_cache_t *cache_cache;
-
- /* Fields set by config directives */
- apr_size_t min_cache_object_size; /* in bytes */
- apr_size_t max_cache_object_size; /* in bytes */
- apr_size_t max_cache_size; /* in bytes */
- apr_size_t max_object_cnt;
- cache_pqueue_set_priority cache_remove_algorithm;
-
- /* maximum amount of data to buffer on a streamed response where
- * we haven't yet seen EOS */
- apr_off_t max_streaming_buffer_size;
-} mem_cache_conf;
-static mem_cache_conf *sconf;
-
-#define DEFAULT_MAX_CACHE_SIZE 100*1024
-#define DEFAULT_MIN_CACHE_OBJECT_SIZE 1
-#define DEFAULT_MAX_CACHE_OBJECT_SIZE 10000
-#define DEFAULT_MAX_OBJECT_CNT 1009
-#define DEFAULT_MAX_STREAMING_BUFFER_SIZE 100000
-#define CACHEFILE_LEN 20
-
-/* Forward declarations */
-static int remove_entity(cache_handle_t *h);
-static apr_status_t store_headers(cache_handle_t *h, request_rec *r, cache_info *i);
-static apr_status_t store_body(cache_handle_t *h, request_rec *r, apr_bucket_brigade *b);
-static apr_status_t recall_headers(cache_handle_t *h, request_rec *r);
-static apr_status_t recall_body(cache_handle_t *h, apr_pool_t *p, apr_bucket_brigade *bb);
-
-static void cleanup_cache_object(cache_object_t *obj);
-
-static long memcache_get_priority(void*a)
-{
- cache_object_t *obj = (cache_object_t *)a;
- mem_cache_object_t *mobj = obj->vobj;
-
- return mobj->priority;
-}
-
-static void memcache_inc_frequency(void*a)
-{
- cache_object_t *obj = (cache_object_t *)a;
- mem_cache_object_t *mobj = obj->vobj;
-
- mobj->total_refs++;
- mobj->priority = 0;
-}
-
-static void memcache_set_pos(void *a, apr_ssize_t pos)
-{
- cache_object_t *obj = (cache_object_t *)a;
- mem_cache_object_t *mobj = obj->vobj;
-
- apr_atomic_set32(&mobj->pos, pos);
-}
-static apr_ssize_t memcache_get_pos(void *a)
-{
- cache_object_t *obj = (cache_object_t *)a;
- mem_cache_object_t *mobj = obj->vobj;
-
- return apr_atomic_read32(&mobj->pos);
-}
-
-static apr_size_t memcache_cache_get_size(void*a)
-{
- cache_object_t *obj = (cache_object_t *)a;
- mem_cache_object_t *mobj = obj->vobj;
- return mobj->m_len;
-}
-/** callback to get the key of a item */
-static const char* memcache_cache_get_key(void*a)
-{
- cache_object_t *obj = (cache_object_t *)a;
- return obj->key;
-}
-/**
- * memcache_cache_free()
- * memcache_cache_free is a callback that is only invoked by a thread
- * running in cache_insert(). cache_insert() runs under protection
- * of sconf->lock. By the time this function has been entered, the cache_object
- * has been ejected from the cache. decrement the refcount and if the refcount drops
- * to 0, cleanup the cache object.
- */
-static void memcache_cache_free(void*a)
-{
- cache_object_t *obj = (cache_object_t *)a;
-
- /* Decrement the refcount to account for the object being ejected
- * from the cache. If the refcount is 0, free the object.
- */
- if (!apr_atomic_dec32(&obj->refcount)) {
- cleanup_cache_object(obj);
- }
-}
-/*
- * functions return a 'negative' score since priority queues
- * dequeue the object with the highest value first
- */
-static long memcache_lru_algorithm(long queue_clock, void *a)
-{
- cache_object_t *obj = (cache_object_t *)a;
- mem_cache_object_t *mobj = obj->vobj;
- if (mobj->priority == 0)
- mobj->priority = queue_clock - mobj->total_refs;
-
- /*
- * a 'proper' LRU function would just be
- * mobj->priority = mobj->total_refs;
- */
- return mobj->priority;
-}
-
-static long memcache_gdsf_algorithm(long queue_clock, void *a)
-{
- cache_object_t *obj = (cache_object_t *)a;
- mem_cache_object_t *mobj = obj->vobj;
-
- if (mobj->priority == 0)
- mobj->priority = queue_clock -
- (long)(mobj->total_refs*1000 / mobj->m_len);
-
- return mobj->priority;
-}
-
-static void cleanup_cache_object(cache_object_t *obj)
-{
- mem_cache_object_t *mobj = obj->vobj;
-
- /* Cleanup the mem_cache_object_t */
- if (mobj) {
- if (mobj->m) {
- free(mobj->m);
- }
- if (mobj->type == CACHE_TYPE_FILE && mobj->fd) {
-#ifdef WIN32
- CloseHandle(mobj->fd);
-#else
- close(mobj->fd);
-#endif
- }
- }
-
- apr_pool_destroy(mobj->pool);
-}
-static apr_status_t decrement_refcount(void *arg)
-{
- cache_object_t *obj = (cache_object_t *) arg;
-
- /* If obj->complete is not set, the cache update failed and the
- * object needs to be removed from the cache then cleaned up.
- * The garbage collector may have ejected the object from the
- * cache already, so make sure it is really still in the cache
- * before attempting to remove it.
- */
- if (!obj->complete) {
- cache_object_t *tobj = NULL;
- if (sconf->lock) {
- apr_thread_mutex_lock(sconf->lock);
- }
- tobj = cache_find(sconf->cache_cache, obj->key);
- if (tobj == obj) {
- cache_remove(sconf->cache_cache, obj);
- apr_atomic_dec32(&obj->refcount);
- }
- if (sconf->lock) {
- apr_thread_mutex_unlock(sconf->lock);
- }
- }
-
- /* If the refcount drops to 0, cleanup the cache object */
- if (!apr_atomic_dec32(&obj->refcount)) {
- cleanup_cache_object(obj);
- }
- return APR_SUCCESS;
-}
-static apr_status_t cleanup_cache_mem(void *sconfv)
-{
- cache_object_t *obj;
- mem_cache_conf *co = (mem_cache_conf*) sconfv;
-
- if (!co) {
- return APR_SUCCESS;
- }
- if (!co->cache_cache) {
- return APR_SUCCESS;
- }
-
- if (sconf->lock) {
- apr_thread_mutex_lock(sconf->lock);
- }
- obj = cache_pop(co->cache_cache);
- while (obj) {
- /* Iterate over the cache and clean up each unreferenced entry */
- if (!apr_atomic_dec32(&obj->refcount)) {
- cleanup_cache_object(obj);
- }
- obj = cache_pop(co->cache_cache);
- }
-
- /* Cache is empty, free the cache table */
- cache_free(co->cache_cache);
-
- if (sconf->lock) {
- apr_thread_mutex_unlock(sconf->lock);
- }
- return APR_SUCCESS;
-}
-/*
- * TODO: enable directives to be overridden in various containers
- */
-static void *create_cache_config(apr_pool_t *p, server_rec *s)
-{
- sconf = apr_pcalloc(p, sizeof(mem_cache_conf));
-
- sconf->min_cache_object_size = DEFAULT_MIN_CACHE_OBJECT_SIZE;
- sconf->max_cache_object_size = DEFAULT_MAX_CACHE_OBJECT_SIZE;
- /* Number of objects in the cache */
- sconf->max_object_cnt = DEFAULT_MAX_OBJECT_CNT;
- /* Size of the cache in bytes */
- sconf->max_cache_size = DEFAULT_MAX_CACHE_SIZE;
- sconf->cache_cache = NULL;
- sconf->cache_remove_algorithm = memcache_gdsf_algorithm;
- sconf->max_streaming_buffer_size = DEFAULT_MAX_STREAMING_BUFFER_SIZE;
-
- return sconf;
-}
-
-static int create_entity(cache_handle_t *h, cache_type_e type_e,
- request_rec *r, const char *key, apr_off_t len)
-{
- apr_status_t rv;
- apr_pool_t *pool;
- cache_object_t *obj, *tmp_obj;
- mem_cache_object_t *mobj;
-
- if (len == -1) {
- /* Caching a streaming response. Assume the response is
- * less than or equal to max_streaming_buffer_size. We will
- * correct all the cache size counters in store_body once
- * we know exactly know how much we are caching.
- */
- len = sconf->max_streaming_buffer_size;
- }
-
- /* Note: cache_insert() will automatically garbage collect
- * objects from the cache if the max_cache_size threshold is
- * exceeded. This means mod_mem_cache does not need to implement
- * max_cache_size checks.
- */
- if (len < sconf->min_cache_object_size ||
- len > sconf->max_cache_object_size) {
- ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
- "mem_cache: URL %s failed the size check and will not be cached.",
- key);
- return DECLINED;
- }
-
- if (type_e == CACHE_TYPE_FILE) {
- /* CACHE_TYPE_FILE is only valid for local content handled by the
- * default handler. Need a better way to check if the file is
- * local or not.
- */
- if (!r->filename) {
- return DECLINED;
- }
- }
-
- rv = apr_pool_create(&pool, NULL);
-
- if (rv != APR_SUCCESS) {
- ap_log_error(APLOG_MARK, APLOG_WARNING, rv, r->server,
- "mem_cache: Failed to create memory pool.");
- return DECLINED;
- }
-
- /* Allocate and initialize cache_object_t */
- obj = apr_pcalloc(pool, sizeof(*obj));
- obj->key = apr_pstrdup(pool, key);
-
- /* Allocate and init mem_cache_object_t */
- mobj = apr_pcalloc(pool, sizeof(*mobj));
- mobj->pool = pool;
-
- /* Finish initing the cache object */
- apr_atomic_set32(&obj->refcount, 1);
- mobj->total_refs = 1;
- obj->complete = 0;
- obj->vobj = mobj;
- /* Safe cast: We tested < sconf->max_cache_object_size above */
- mobj->m_len = (apr_size_t)len;
- mobj->type = type_e;
-
- /* Place the cache_object_t into the hash table.
- * Note: Perhaps we should wait to put the object in the
- * hash table when the object is complete? I add the object here to
- * avoid multiple threads attempting to cache the same content only
- * to discover at the very end that only one of them will succeed.
- * Furthermore, adding the cache object to the table at the end could
- * open up a subtle but easy to exploit DoS hole: someone could request
- * a very large file with multiple requests. Better to detect this here
- * rather than after the cache object has been completely built and
- * initialized...
- * XXX Need a way to insert into the cache w/o such coarse grained locking
- */
- if (sconf->lock) {
- apr_thread_mutex_lock(sconf->lock);
- }
- tmp_obj = (cache_object_t *) cache_find(sconf->cache_cache, key);
-
- if (!tmp_obj) {
- cache_insert(sconf->cache_cache, obj);
- /* Add a refcount to account for the reference by the
- * hashtable in the cache. Refcount should be 2 now, one
- * for this thread, and one for the cache.
- */
- apr_atomic_inc32(&obj->refcount);
- }
- if (sconf->lock) {
- apr_thread_mutex_unlock(sconf->lock);
- }
-
- if (tmp_obj) {
- /* This thread collided with another thread loading the same object
- * into the cache at the same time. Defer to the other thread which
- * is further along.
- */
- cleanup_cache_object(obj);
- return DECLINED;
- }
-
- apr_pool_cleanup_register(r->pool, obj, decrement_refcount,
- apr_pool_cleanup_null);
-
- /* Populate the cache handle */
- h->cache_obj = obj;
-
- return OK;
-}
-
-static int create_mem_entity(cache_handle_t *h, request_rec *r,
- const char *key, apr_off_t len)
-{
- return create_entity(h, CACHE_TYPE_HEAP, r, key, len);
-}
-
-static int create_fd_entity(cache_handle_t *h, request_rec *r,
- const char *key, apr_off_t len)
-{
- return create_entity(h, CACHE_TYPE_FILE, r, key, len);
-}
-
-static int open_entity(cache_handle_t *h, request_rec *r, const char *key)
-{
- cache_object_t *obj;
-
- /* Look up entity keyed to 'url' */
- if (sconf->lock) {
- apr_thread_mutex_lock(sconf->lock);
- }
- obj = (cache_object_t *) cache_find(sconf->cache_cache, key);
- if (obj) {
- if (obj->complete) {
- request_rec *rmain=r, *rtmp;
- apr_atomic_inc32(&obj->refcount);
- /* cache is worried about overall counts, not 'open' ones */
- cache_update(sconf->cache_cache, obj);
-
- /* If this is a subrequest, register the cleanup against
- * the main request. This will prevent the cache object
- * from being cleaned up from under the request after the
- * subrequest is destroyed.
- */
- rtmp = r;
- while (rtmp) {
- rmain = rtmp;
- rtmp = rmain->main;
- }
- apr_pool_cleanup_register(rmain->pool, obj, decrement_refcount,
- apr_pool_cleanup_null);
- }
- else {
- obj = NULL;
- }
- }
-
- if (sconf->lock) {
- apr_thread_mutex_unlock(sconf->lock);
- }
-
- if (!obj) {
- return DECLINED;
- }
-
- /* Initialize the cache_handle */
- h->cache_obj = obj;
- h->req_hdrs = NULL; /* Pick these up in recall_headers() */
- return OK;
-}
-
-/* remove_entity()
- * Notes:
- * refcount should be at least 1 upon entry to this function to account
- * for this thread's reference to the object. If the refcount is 1, then
- * object has been removed from the cache by another thread and this thread
- * is the last thread accessing the object.
- */
-static int remove_entity(cache_handle_t *h)
-{
- cache_object_t *obj = h->cache_obj;
- cache_object_t *tobj = NULL;
-
- if (sconf->lock) {
- apr_thread_mutex_lock(sconf->lock);
- }
-
- /* If the entity is still in the cache, remove it and decrement the
- * refcount. If the entity is not in the cache, do nothing. In both cases
- * decrement_refcount called by the last thread referencing the object will
- * trigger the cleanup.
- */
- tobj = cache_find(sconf->cache_cache, obj->key);
- if (tobj == obj) {
- cache_remove(sconf->cache_cache, obj);
- apr_atomic_dec32(&obj->refcount);
- }
-
- if (sconf->lock) {
- apr_thread_mutex_unlock(sconf->lock);
- }
-
- return OK;
-}
-
-/* Define request processing hook handlers */
-/* remove_url()
- * Notes:
- */
-static int remove_url(cache_handle_t *h, apr_pool_t *p)
-{
- cache_object_t *obj;
- int cleanup = 0;
-
- if (sconf->lock) {
- apr_thread_mutex_lock(sconf->lock);
- }
-
- obj = h->cache_obj;
- if (obj) {
- cache_remove(sconf->cache_cache, obj);
- /* For performance, cleanup cache object after releasing the lock */
- cleanup = !apr_atomic_dec32(&obj->refcount);
- }
- if (sconf->lock) {
- apr_thread_mutex_unlock(sconf->lock);
- }
-
- if (cleanup) {
- cleanup_cache_object(obj);
- }
-
- return OK;
-}
-
-static apr_table_t *deep_table_copy(apr_pool_t *p, const apr_table_t *table)
-{
- const apr_array_header_t *array = apr_table_elts(table);
- apr_table_entry_t *elts = (apr_table_entry_t *) array->elts;
- apr_table_t *copy = apr_table_make(p, array->nelts);
- int i;
-
- for (i = 0; i < array->nelts; i++) {
- if (elts[i].key) {
- apr_table_add(copy, elts[i].key, elts[i].val);
- }
- }
-
- return copy;
-}
-
-static apr_status_t recall_headers(cache_handle_t *h, request_rec *r)
-{
- mem_cache_object_t *mobj = (mem_cache_object_t*) h->cache_obj->vobj;
-
- h->req_hdrs = deep_table_copy(r->pool, mobj->req_hdrs);
- h->resp_hdrs = deep_table_copy(r->pool, mobj->header_out);
-
- return OK;
-}
-
-static apr_status_t recall_body(cache_handle_t *h, apr_pool_t *p, apr_bucket_brigade *bb)
-{
- apr_bucket *b;
- mem_cache_object_t *mobj = (mem_cache_object_t*) h->cache_obj->vobj;
-
- if (mobj->type == CACHE_TYPE_FILE) {
- /* CACHE_TYPE_FILE */
- apr_file_t *file;
- apr_os_file_put(&file, &mobj->fd, mobj->flags, p);
-
- apr_brigade_insert_file(bb, file, 0, mobj->m_len, p);
- }
- else {
- /* CACHE_TYPE_HEAP */
- b = apr_bucket_immortal_create(mobj->m, mobj->m_len, bb->bucket_alloc);
- APR_BRIGADE_INSERT_TAIL(bb, b);
- }
- b = apr_bucket_eos_create(bb->bucket_alloc);
- APR_BRIGADE_INSERT_TAIL(bb, b);
-
- return APR_SUCCESS;
-}
-
-
-static apr_status_t store_headers(cache_handle_t *h, request_rec *r, cache_info *info)
-{
- cache_object_t *obj = h->cache_obj;
- mem_cache_object_t *mobj = (mem_cache_object_t*) obj->vobj;
- apr_table_t *headers_out;
-
- /*
- * The cache needs to keep track of the following information:
- * - Date, LastMod, Version, ReqTime, RespTime, ContentLength
- * - The original request headers (for Vary)
- * - The original response headers (for returning with a cached response)
- * - The body of the message
- */
- mobj->req_hdrs = deep_table_copy(mobj->pool, r->headers_in);
-
- /* Precompute how much storage we need to hold the headers */
- headers_out = ap_cache_cacheable_headers_out(r);
-
- mobj->header_out = deep_table_copy(mobj->pool, headers_out);
-
- /* Init the info struct */
- obj->info.status = info->status;
- if (info->date) {
- obj->info.date = info->date;
- }
- if (info->response_time) {
- obj->info.response_time = info->response_time;
- }
- if (info->request_time) {
- obj->info.request_time = info->request_time;
- }
- if (info->expire) {
- obj->info.expire = info->expire;
- }
-
- return APR_SUCCESS;
-}
-
-static apr_status_t store_body(cache_handle_t *h, request_rec *r, apr_bucket_brigade *b)
-{
- apr_status_t rv;
- cache_object_t *obj = h->cache_obj;
- cache_object_t *tobj = NULL;
- mem_cache_object_t *mobj = (mem_cache_object_t*) obj->vobj;
- apr_read_type_e eblock = APR_BLOCK_READ;
- apr_bucket *e;
- char *cur;
- int eos = 0;
-
- if (mobj->type == CACHE_TYPE_FILE) {
- apr_file_t *file = NULL;
- int fd = 0;
- int other = 0;
-
- /* We can cache an open file descriptor if:
- * - the brigade contains one and only one file_bucket &&
- * - the brigade is complete &&
- * - the file_bucket is the last data bucket in the brigade
- */
- for (e = APR_BRIGADE_FIRST(b);
- e != APR_BRIGADE_SENTINEL(b);
- e = APR_BUCKET_NEXT(e))
- {
- if (APR_BUCKET_IS_EOS(e)) {
- eos = 1;
- }
- else if (APR_BUCKET_IS_FILE(e)) {
- apr_bucket_file *a = e->data;
- fd++;
- file = a->fd;
- }
- else {
- other++;
- }
- }
- if (fd == 1 && !other && eos) {
- apr_file_t *tmpfile;
- const char *name;
- /* Open a new XTHREAD handle to the file */
- apr_file_name_get(&name, file);
- mobj->flags = ((APR_SENDFILE_ENABLED & apr_file_flags_get(file))
- | APR_READ | APR_BINARY | APR_XTHREAD | APR_FILE_NOCLEANUP);
- rv = apr_file_open(&tmpfile, name, mobj->flags,
- APR_OS_DEFAULT, r->pool);
- if (rv != APR_SUCCESS) {
- return rv;
- }
- apr_file_inherit_unset(tmpfile);
- apr_os_file_get(&(mobj->fd), tmpfile);
-
- /* Open for business */
- ap_log_error(APLOG_MARK, APLOG_INFO, 0, r->server,
- "mem_cache: Cached file: %s with key: %s", name, obj->key);
- obj->complete = 1;
- return APR_SUCCESS;
- }
-
- /* Content not suitable for fd caching. Cache in-memory instead. */
- mobj->type = CACHE_TYPE_HEAP;
- }
-
- /*
- * FD cacheing is not enabled or the content was not
- * suitable for fd caching.
- */
- if (mobj->m == NULL) {
- mobj->m = malloc(mobj->m_len);
- if (mobj->m == NULL) {
- return APR_ENOMEM;
- }
- obj->count = 0;
- }
- cur = (char*) mobj->m + obj->count;
-
- /* Iterate accross the brigade and populate the cache storage */
- for (e = APR_BRIGADE_FIRST(b);
- e != APR_BRIGADE_SENTINEL(b);
- e = APR_BUCKET_NEXT(e))
- {
- const char *s;
- apr_size_t len;
-
- if (APR_BUCKET_IS_EOS(e)) {
- if (mobj->m_len > obj->count) {
- /* Caching a streamed response. Reallocate a buffer of the
- * correct size and copy the streamed response into that
- * buffer */
- mobj->m = realloc(mobj->m, obj->count);
- if (!mobj->m) {
- return APR_ENOMEM;
- }
-
- /* Now comes the crufty part... there is no way to tell the
- * cache that the size of the object has changed. We need
- * to remove the object, update the size and re-add the
- * object, all under protection of the lock.
- */
- if (sconf->lock) {
- apr_thread_mutex_lock(sconf->lock);
- }
- /* Has the object been ejected from the cache?
- */
- tobj = (cache_object_t *) cache_find(sconf->cache_cache, obj->key);
- if (tobj == obj) {
- /* Object is still in the cache, remove it, update the len field then
- * replace it under protection of sconf->lock.
- */
- cache_remove(sconf->cache_cache, obj);
- /* For illustration, cache no longer has reference to the object
- * so decrement the refcount
- * apr_atomic_dec32(&obj->refcount);
- */
- mobj->m_len = obj->count;
-
- cache_insert(sconf->cache_cache, obj);
- /* For illustration, cache now has reference to the object, so
- * increment the refcount
- * apr_atomic_inc32(&obj->refcount);
- */
- }
- else if (tobj) {
- /* Different object with the same key found in the cache. Doing nothing
- * here will cause the object refcount to drop to 0 in decrement_refcount
- * and the object will be cleaned up.
- */
-
- } else {
- /* Object has been ejected from the cache, add it back to the cache */
- mobj->m_len = obj->count;
- cache_insert(sconf->cache_cache, obj);
- apr_atomic_inc32(&obj->refcount);
- }
-
- if (sconf->lock) {
- apr_thread_mutex_unlock(sconf->lock);
- }
- }
- /* Open for business */
- ap_log_error(APLOG_MARK, APLOG_INFO, 0, r->server,
- "mem_cache: Cached url: %s", obj->key);
- obj->complete = 1;
- break;
- }
- rv = apr_bucket_read(e, &s, &len, eblock);
- if (rv != APR_SUCCESS) {
- return rv;
- }
- if (len) {
- /* Check for buffer overflow */
- if ((obj->count + len) > mobj->m_len) {
- return APR_ENOMEM;
- }
- else {
- memcpy(cur, s, len);
- cur+=len;
- obj->count+=len;
- }
- }
- /* This should not fail, but if it does, we are in BIG trouble
- * cause we just stomped all over the heap.
- */
- AP_DEBUG_ASSERT(obj->count <= mobj->m_len);
- }
- return APR_SUCCESS;
-}
-/**
- * Configuration and start-up
- */
-static int mem_cache_post_config(apr_pool_t *p, apr_pool_t *plog,
- apr_pool_t *ptemp, server_rec *s)
-{
- int threaded_mpm;
-
- /* Sanity check the cache configuration */
- if (sconf->min_cache_object_size >= sconf->max_cache_object_size) {
- ap_log_error(APLOG_MARK, APLOG_CRIT, 0, s,
- "MCacheMaxObjectSize must be greater than MCacheMinObjectSize");
- return DONE;
- }
- if (sconf->max_cache_object_size >= sconf->max_cache_size) {
- ap_log_error(APLOG_MARK, APLOG_CRIT, 0, s,
- "MCacheSize must be greater than MCacheMaxObjectSize");
- return DONE;
- }
- if (sconf->max_streaming_buffer_size > sconf->max_cache_object_size) {
- /* Issue a notice only if something other than the default config
- * is being used */
- if (sconf->max_streaming_buffer_size != DEFAULT_MAX_STREAMING_BUFFER_SIZE &&
- sconf->max_cache_object_size != DEFAULT_MAX_CACHE_OBJECT_SIZE) {
- ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, s,
- "MCacheMaxStreamingBuffer must be less than or equal to MCacheMaxObjectSize. "
- "Resetting MCacheMaxStreamingBuffer to MCacheMaxObjectSize.");
- }
- sconf->max_streaming_buffer_size = sconf->max_cache_object_size;
- }
- if (sconf->max_streaming_buffer_size < sconf->min_cache_object_size) {
- ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
- "MCacheMaxStreamingBuffer must be greater than or equal to MCacheMinObjectSize. "
- "Resetting MCacheMaxStreamingBuffer to MCacheMinObjectSize.");
- sconf->max_streaming_buffer_size = sconf->min_cache_object_size;
- }
- ap_mpm_query(AP_MPMQ_IS_THREADED, &threaded_mpm);
- if (threaded_mpm) {
- apr_thread_mutex_create(&sconf->lock, APR_THREAD_MUTEX_DEFAULT, p);
- }
-
- sconf->cache_cache = cache_init(sconf->max_object_cnt,
- sconf->max_cache_size,
- memcache_get_priority,
- sconf->cache_remove_algorithm,
- memcache_get_pos,
- memcache_set_pos,
- memcache_inc_frequency,
- memcache_cache_get_size,
- memcache_cache_get_key,
- memcache_cache_free);
- apr_pool_cleanup_register(p, sconf, cleanup_cache_mem, apr_pool_cleanup_null);
-
- if (sconf->cache_cache)
- return OK;
-
- return -1;
-
-}
-
-static const char
-*set_max_cache_size(cmd_parms *parms, void *in_struct_ptr, const char *arg)
-{
- apr_size_t val;
-
- if (sscanf(arg, "%" APR_SIZE_T_FMT, &val) != 1) {
- return "MCacheSize argument must be an integer representing the max cache size in KBytes.";
- }
- sconf->max_cache_size = val*1024;
- return NULL;
-}
-static const char
-*set_min_cache_object_size(cmd_parms *parms, void *in_struct_ptr, const char *arg)
-{
- apr_size_t val;
-
- if (sscanf(arg, "%" APR_SIZE_T_FMT, &val) != 1) {
- return "MCacheMinObjectSize value must be an positive integer (bytes)";
- }
- if (val > 0)
- sconf->min_cache_object_size = val;
- else
- return "MCacheMinObjectSize value must be an positive integer (bytes)";
- return NULL;
-}
-static const char
-*set_max_cache_object_size(cmd_parms *parms, void *in_struct_ptr, const char *arg)
-{
- apr_size_t val;
-
- if (sscanf(arg, "%" APR_SIZE_T_FMT, &val) != 1) {
- return "MCacheMaxObjectSize value must be an integer (bytes)";
- }
- sconf->max_cache_object_size = val;
- return NULL;
-}
-static const char
-*set_max_object_count(cmd_parms *parms, void *in_struct_ptr, const char *arg)
-{
- apr_size_t val;
-
- if (sscanf(arg, "%" APR_SIZE_T_FMT, &val) != 1) {
- return "MCacheMaxObjectCount value must be an integer";
- }
- sconf->max_object_cnt = val;
- return NULL;
-}
-
-static const char
-*set_cache_removal_algorithm(cmd_parms *parms, void *name, const char *arg)
-{
- if (strcasecmp("LRU", arg)) {
- sconf->cache_remove_algorithm = memcache_lru_algorithm;
- }
- else {
- if (strcasecmp("GDSF", arg)) {
- sconf->cache_remove_algorithm = memcache_gdsf_algorithm;
- }
- else {
- return "currently implemented algorithms are LRU and GDSF";
- }
- }
- return NULL;
-}
-
-static const char *set_max_streaming_buffer(cmd_parms *parms, void *dummy,
- const char *arg)
-{
- char *err;
- if (apr_strtoff(&sconf->max_streaming_buffer_size, arg, &err, 10) || *err) {
- return "MCacheMaxStreamingBuffer value must be a number";
- }
-
- return NULL;
-}
-
-static const command_rec cache_cmds[] =
-{
- AP_INIT_TAKE1("MCacheSize", set_max_cache_size, NULL, RSRC_CONF,
- "The maximum amount of memory used by the cache in KBytes"),
- AP_INIT_TAKE1("MCacheMaxObjectCount", set_max_object_count, NULL, RSRC_CONF,
- "The maximum number of objects allowed to be placed in the cache"),
- AP_INIT_TAKE1("MCacheMinObjectSize", set_min_cache_object_size, NULL, RSRC_CONF,
- "The minimum size (in bytes) of an object to be placed in the cache"),
- AP_INIT_TAKE1("MCacheMaxObjectSize", set_max_cache_object_size, NULL, RSRC_CONF,
- "The maximum size (in bytes) of an object to be placed in the cache"),
- AP_INIT_TAKE1("MCacheRemovalAlgorithm", set_cache_removal_algorithm, NULL, RSRC_CONF,
- "The algorithm used to remove entries from the cache (default: GDSF)"),
- AP_INIT_TAKE1("MCacheMaxStreamingBuffer", set_max_streaming_buffer, NULL, RSRC_CONF,
- "Maximum number of bytes of content to buffer for a streamed response"),
- {NULL}
-};
-
-static const cache_provider cache_mem_provider =
-{
- &remove_entity,
- &store_headers,
- &store_body,
- &recall_headers,
- &recall_body,
- &create_mem_entity,
- &open_entity,
- &remove_url,
-};
-
-static const cache_provider cache_fd_provider =
-{
- &remove_entity,
- &store_headers,
- &store_body,
- &recall_headers,
- &recall_body,
- &create_fd_entity,
- &open_entity,
- &remove_url,
-};
-
-static void register_hooks(apr_pool_t *p)
-{
- ap_hook_post_config(mem_cache_post_config, NULL, NULL, APR_HOOK_MIDDLE);
- /* cache initializer */
- /* cache_hook_init(cache_mem_init, NULL, NULL, APR_HOOK_MIDDLE); */
- /*
- cache_hook_create_entity(create_entity, NULL, NULL, APR_HOOK_MIDDLE);
- cache_hook_open_entity(open_entity, NULL, NULL, APR_HOOK_MIDDLE);
- cache_hook_remove_url(remove_url, NULL, NULL, APR_HOOK_MIDDLE);
- */
- ap_register_provider(p, CACHE_PROVIDER_GROUP, "mem", "0",
- &cache_mem_provider);
- ap_register_provider(p, CACHE_PROVIDER_GROUP, "fd", "0",
- &cache_fd_provider);
-}
-
-module AP_MODULE_DECLARE_DATA mem_cache_module =
-{
- STANDARD20_MODULE_STUFF,
- NULL, /* create per-directory config structure */
- NULL, /* merge per-directory config structures */
- create_cache_config, /* create per-server config structure */
- NULL, /* merge per-server config structures */
- cache_cmds, /* command apr_table_t */
- register_hooks
-};
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