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| -rw-r--r-- | modules/cache/cache_util.h | 341 |
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diff --git a/modules/cache/cache_util.h b/modules/cache/cache_util.h new file mode 100644 index 0000000..6b92151 --- /dev/null +++ b/modules/cache/cache_util.h @@ -0,0 +1,341 @@ +/* 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 cache_util.h + * @brief Cache Storage Functions + * + * @defgroup Cache_util Cache Utility Functions + * @ingroup MOD_CACHE + * @{ + */ + +#ifndef CACHE_UTIL_H +#define CACHE_UTIL_H + +#ifdef __cplusplus +extern "C" { +#endif + +#include "mod_cache.h" + +#include "apr_hooks.h" +#include "apr.h" +#include "apr_lib.h" +#include "apr_strings.h" +#include "apr_buckets.h" +#include "apr_md5.h" +#include "apr_pools.h" +#include "apr_strings.h" +#include "apr_optional.h" +#define APR_WANT_STRFUNC +#include "apr_want.h" + +#include "httpd.h" +#include "http_config.h" +#include "ap_config.h" +#include "http_core.h" +#include "http_protocol.h" +#include "http_request.h" +#include "http_vhost.h" +#include "http_main.h" +#include "http_log.h" +#include "http_connection.h" +#include "util_filter.h" +#include "apr_uri.h" + +#ifdef HAVE_NETDB_H +#include <netdb.h> +#endif + +#ifdef HAVE_SYS_SOCKET_H +#include <sys/socket.h> +#endif + +#ifdef HAVE_NETINET_IN_H +#include <netinet/in.h> +#endif + +#ifdef HAVE_ARPA_INET_H +#include <arpa/inet.h> +#endif + +#include "apr_atomic.h" + +#ifndef MAX +#define MAX(a,b) ((a) > (b) ? (a) : (b)) +#endif +#ifndef MIN +#define MIN(a,b) ((a) < (b) ? (a) : (b)) +#endif + +#define MSEC_ONE_DAY ((apr_time_t)(86400*APR_USEC_PER_SEC)) /* one day, in microseconds */ +#define MSEC_ONE_HR ((apr_time_t)(3600*APR_USEC_PER_SEC)) /* one hour, in microseconds */ +#define MSEC_ONE_MIN ((apr_time_t)(60*APR_USEC_PER_SEC)) /* one minute, in microseconds */ +#define MSEC_ONE_SEC ((apr_time_t)(APR_USEC_PER_SEC)) /* one second, in microseconds */ + +#define DEFAULT_CACHE_MAXEXPIRE MSEC_ONE_DAY +#define DEFAULT_CACHE_MINEXPIRE 0 +#define DEFAULT_CACHE_EXPIRE MSEC_ONE_HR +#define DEFAULT_CACHE_LMFACTOR (0.1) +#define DEFAULT_CACHE_MAXAGE 5 +#define DEFAULT_X_CACHE 0 +#define DEFAULT_X_CACHE_DETAIL 0 +#define DEFAULT_CACHE_STALE_ON_ERROR 1 +#define DEFAULT_CACHE_LOCKPATH "/mod_cache-lock" +#define CACHE_LOCKNAME_KEY "mod_cache-lockname" +#define CACHE_LOCKFILE_KEY "mod_cache-lockfile" +#define CACHE_CTX_KEY "mod_cache-ctx" +#define CACHE_SEPARATOR ", \t" + +/** + * cache_util.c + */ + +struct cache_enable { + apr_uri_t url; + const char *type; + apr_size_t pathlen; +}; + +struct cache_disable { + apr_uri_t url; + apr_size_t pathlen; +}; + +/* static information about the local cache */ +typedef struct { + apr_array_header_t *cacheenable; /* URLs to cache */ + apr_array_header_t *cachedisable; /* URLs not to cache */ + /** store the headers that should not be stored in the cache */ + apr_array_header_t *ignore_headers; + /** store the identifiers that should not be used for key calculation */ + apr_array_header_t *ignore_session_id; + const char *lockpath; + apr_time_t lockmaxage; + apr_uri_t *base_uri; + /** ignore client's requests for uncached responses */ + unsigned int ignorecachecontrol:1; + /** ignore query-string when caching */ + unsigned int ignorequerystring:1; + /** run within the quick handler */ + unsigned int quick:1; + /* thundering herd lock */ + unsigned int lock:1; + unsigned int x_cache:1; + unsigned int x_cache_detail:1; + /* flag if CacheIgnoreHeader has been set */ + #define CACHE_IGNORE_HEADERS_SET 1 + #define CACHE_IGNORE_HEADERS_UNSET 0 + unsigned int ignore_headers_set:1; + /* flag if CacheIgnoreURLSessionIdentifiers has been set */ + #define CACHE_IGNORE_SESSION_ID_SET 1 + #define CACHE_IGNORE_SESSION_ID_UNSET 0 + unsigned int ignore_session_id_set:1; + unsigned int base_uri_set:1; + unsigned int ignorecachecontrol_set:1; + unsigned int ignorequerystring_set:1; + unsigned int quick_set:1; + unsigned int lock_set:1; + unsigned int lockpath_set:1; + unsigned int lockmaxage_set:1; + unsigned int x_cache_set:1; + unsigned int x_cache_detail_set:1; +} cache_server_conf; + +typedef struct { + /* Minimum time to keep cached files in msecs */ + apr_time_t minex; + /* Maximum time to keep cached files in msecs */ + apr_time_t maxex; + /* default time to keep cached file in msecs */ + apr_time_t defex; + /* factor for estimating expires date */ + double factor; + /* cache enabled for this location */ + apr_array_header_t *cacheenable; + /* cache disabled for this location */ + unsigned int disable:1; + /* set X-Cache headers */ + unsigned int x_cache:1; + unsigned int x_cache_detail:1; + /* serve stale on error */ + unsigned int stale_on_error:1; + /** ignore the last-modified header when deciding to cache this request */ + unsigned int no_last_mod_ignore:1; + /** ignore expiration date from server */ + unsigned int store_expired:1; + /** ignore Cache-Control: private header from server */ + unsigned int store_private:1; + /** ignore Cache-Control: no-store header from client or server */ + unsigned int store_nostore:1; + unsigned int minex_set:1; + unsigned int maxex_set:1; + unsigned int defex_set:1; + unsigned int factor_set:1; + unsigned int x_cache_set:1; + unsigned int x_cache_detail_set:1; + unsigned int stale_on_error_set:1; + unsigned int no_last_mod_ignore_set:1; + unsigned int store_expired_set:1; + unsigned int store_private_set:1; + unsigned int store_nostore_set:1; + unsigned int enable_set:1; + unsigned int disable_set:1; +} cache_dir_conf; + +/* A linked-list of authn providers. */ +typedef struct cache_provider_list cache_provider_list; + +struct cache_provider_list { + const char *provider_name; + const cache_provider *provider; + cache_provider_list *next; +}; + +/* per request cache information */ +typedef struct { + cache_provider_list *providers; /* possible cache providers */ + const cache_provider *provider; /* current cache provider */ + const char *provider_name; /* current cache provider name */ + int fresh; /* is the entity fresh? */ + cache_handle_t *handle; /* current cache handle */ + cache_handle_t *stale_handle; /* stale cache handle */ + apr_table_t *stale_headers; /* original request headers. */ + int in_checked; /* CACHE_SAVE must cache the entity */ + int block_response; /* CACHE_SAVE must block response. */ + apr_bucket_brigade *saved_brigade; /* copy of partial response */ + apr_off_t saved_size; /* length of saved_brigade */ + apr_time_t exp; /* expiration */ + apr_time_t lastmod; /* last-modified time */ + cache_info *info; /* current cache info */ + ap_filter_t *save_filter; /* Enable us to restore the filter on error */ + ap_filter_t *remove_url_filter; /* Enable us to remove the filter */ + const char *key; /* The cache key created for this + * request + */ + apr_off_t size; /* the content length from the headers, or -1 */ + apr_bucket_brigade *out; /* brigade to reuse for upstream responses */ + cache_control_t control_in; /* cache control incoming */ +} cache_request_rec; + +/** + * Check the whether the request allows a cached object to be served as per RFC2616 + * section 14.9.4 (Cache Revalidation and Reload Controls) + * @param cache cache_request_rec + * @param r request_rec + * @return 0 ==> cache object may not be served, 1 ==> cache object may be served + */ +int ap_cache_check_no_cache(cache_request_rec *cache, request_rec *r); + +/** + * Check the whether the request allows a cached object to be stored as per RFC2616 + * section 14.9.2 (What May be Stored by Caches) + * @param cache cache_request_rec + * @param r request_rec + * @return 0 ==> cache object may not be served, 1 ==> cache object may be served + */ +int ap_cache_check_no_store(cache_request_rec *cache, request_rec *r); + +/** + * Check the freshness of the cache object per RFC2616 section 13.2 (Expiration Model) + * @param h cache_handle_t + * @param cache cache_request_rec + * @param r request_rec + * @return 0 ==> cache object is stale, 1 ==> cache object is fresh + */ +int cache_check_freshness(cache_handle_t *h, cache_request_rec *cache, + request_rec *r); + +/** + * Try obtain a cache wide lock on the given cache key. + * + * If we return APR_SUCCESS, we obtained the lock, and we are clear to + * proceed to the backend. If we return APR_EEXISTS, then the lock is + * already locked, someone else has gone to refresh the backend data + * already, so we must return stale data with a warning in the mean + * time. If we return anything else, then something has gone pear + * shaped, and we allow the request through to the backend regardless. + * + * This lock is created from the request pool, meaning that should + * something go wrong and the lock isn't deleted on return of the + * request headers from the backend for whatever reason, at worst the + * lock will be cleaned up when the request is dies or finishes. + * + * If something goes truly bananas and the lock isn't deleted when the + * request dies, the lock will be trashed when its max-age is reached, + * or when a request arrives containing a Cache-Control: no-cache. At + * no point is it possible for this lock to permanently deny access to + * the backend. + */ +apr_status_t cache_try_lock(cache_server_conf *conf, cache_request_rec *cache, + request_rec *r); + +/** + * Remove the cache lock, if present. + * + * First, try to close the file handle, whose delete-on-close should + * kill the file. Otherwise, just delete the file by name. + * + * If no lock name has yet been calculated, do the calculation of the + * lock name first before trying to delete the file. + * + * If an optional bucket brigade is passed, the lock will only be + * removed if the bucket brigade contains an EOS bucket. + */ +apr_status_t cache_remove_lock(cache_server_conf *conf, + cache_request_rec *cache, request_rec *r, apr_bucket_brigade *bb); + +cache_provider_list *cache_get_providers(request_rec *r, + cache_server_conf *conf); + +/** + * Get a value from a table, where the table may contain multiple + * values for a given key. + * + * When the table contains a single value, that value is returned + * unchanged. + * + * When the table contains two or more values for a key, all values + * for the key are returned, separated by commas. + */ +const char *cache_table_getm(apr_pool_t *p, const apr_table_t *t, + const char *key); + +/** + * String tokenizer that ignores separator characters within quoted strings + * and escaped characters, as per RFC2616 section 2.2. + */ +char *cache_strqtok(char *str, const char *sep, char **last); + +/** + * Merge err_headers_out into headers_out and add request's Content-Type and + * Content-Encoding if available. + */ +apr_table_t *cache_merge_headers_out(request_rec *r); + +/** + * Return whether to use request's path/query from early stage (r->parsed_uri) + * or the current/rewritable ones (r->uri/r->args). + */ +int cache_use_early_url(request_rec *r); + +#ifdef __cplusplus +} +#endif + +#endif /* !CACHE_UTIL_H */ +/** @} */ |