00001 /* Licensed to the Apache Software Foundation (ASF) under one or more 00002 * contributor license agreements. See the NOTICE file distributed with 00003 * this work for additional information regarding copyright ownership. 00004 * The ASF licenses this file to You under the Apache License, Version 2.0 00005 * (the "License"); you may not use this file except in compliance with 00006 * the License. You may obtain a copy of the License at 00007 * 00008 * http://www.apache.org/licenses/LICENSE-2.0 00009 * 00010 * Unless required by applicable law or agreed to in writing, software 00011 * distributed under the License is distributed on an "AS IS" BASIS, 00012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 00013 * See the License for the specific language governing permissions and 00014 * limitations under the License. 00015 */ 00016 00026 #ifndef AP_MPM_H 00027 #define AP_MPM_H 00028 00029 #include "apr_thread_proc.h" 00030 00031 /* 00032 The MPM, "multi-processing model" provides an abstraction of the 00033 interface with the OS for distributing incoming connections to 00034 threads/process for processing. http_main invokes the MPM, and 00035 the MPM runs until a shutdown/restart has been indicated. 00036 The MPM calls out to the apache core via the ap_process_connection 00037 function when a connection arrives. 00038 00039 The MPM may or may not be multithreaded. In the event that it is 00040 multithreaded, at any instant it guarantees a 1:1 mapping of threads 00041 ap_process_connection invocations. 00042 00043 Note: In the future it will be possible for ap_process_connection 00044 to return to the MPM prior to finishing the entire connection; and 00045 the MPM will proceed with asynchronous handling for the connection; 00046 in the future the MPM may call ap_process_connection again -- but 00047 does not guarantee it will occur on the same thread as the first call. 00048 00049 The MPM further guarantees that no asynchronous behaviour such as 00050 longjmps and signals will interfere with the user code that is 00051 invoked through ap_process_connection. The MPM may reserve some 00052 signals for its use (i.e. SIGUSR1), but guarantees that these signals 00053 are ignored when executing outside the MPM code itself. (This 00054 allows broken user code that does not handle EINTR to function 00055 properly.) 00056 00057 The suggested server restart and stop behaviour will be "graceful". 00058 However the MPM may choose to terminate processes when the user 00059 requests a non-graceful restart/stop. When this occurs, the MPM kills 00060 all threads with extreme prejudice, and destroys the pchild pool. 00061 User cleanups registered in the pchild apr_pool_t will be invoked at 00062 this point. (This can pose some complications, the user cleanups 00063 are asynchronous behaviour not unlike longjmp/signal... but if the 00064 admin is asking for a non-graceful shutdown, how much effort should 00065 we put into doing it in a nice way?) 00066 00067 unix/posix notes: 00068 - The MPM does not set a SIGALRM handler, user code may use SIGALRM. 00069 But the preferred method of handling timeouts is to use the 00070 timeouts provided by the BUFF abstraction. 00071 - The proper setting for SIGPIPE is SIG_IGN, if user code changes it 00072 for any of their own processing, it must be restored to SIG_IGN 00073 prior to executing or returning to any apache code. 00074 TODO: add SIGPIPE debugging check somewhere to make sure it's SIG_IGN 00075 */ 00076 00087 AP_DECLARE(int) ap_mpm_run(apr_pool_t *pconf, apr_pool_t *plog, server_rec *server_conf); 00088 00095 AP_DECLARE(int) ap_graceful_stop_signalled(void); 00096 00110 AP_DECLARE(apr_status_t) ap_os_create_privileged_process( 00111 const request_rec *r, 00112 apr_proc_t *newproc, 00113 const char *progname, 00114 const char * const *args, 00115 const char * const *env, 00116 apr_procattr_t *attr, 00117 apr_pool_t *p); 00118 00119 /* Subtypes/Values for AP_MPMQ_IS_THREADED and AP_MPMQ_IS_FORKED */ 00120 #define AP_MPMQ_NOT_SUPPORTED 0 /* This value specifies whether */ 00121 /* an MPM is capable of */ 00122 /* threading or forking. */ 00123 #define AP_MPMQ_STATIC 1 /* This value specifies whether */ 00124 /* an MPM is using a static # */ 00125 /* threads or daemons. */ 00126 #define AP_MPMQ_DYNAMIC 2 /* This value specifies whether */ 00127 /* an MPM is using a dynamic # */ 00128 /* threads or daemons. */ 00129 00130 /* Values returned for AP_MPMQ_MPM_STATE */ 00131 #define AP_MPMQ_STARTING 0 00132 #define AP_MPMQ_RUNNING 1 00133 #define AP_MPMQ_STOPPING 2 00134 00135 #define AP_MPMQ_MAX_DAEMON_USED 1 /* Max # of daemons used so far */ 00136 #define AP_MPMQ_IS_THREADED 2 /* MPM can do threading */ 00137 #define AP_MPMQ_IS_FORKED 3 /* MPM can do forking */ 00138 #define AP_MPMQ_HARD_LIMIT_DAEMONS 4 /* The compiled max # daemons */ 00139 #define AP_MPMQ_HARD_LIMIT_THREADS 5 /* The compiled max # threads */ 00140 #define AP_MPMQ_MAX_THREADS 6 /* # of threads/child by config */ 00141 #define AP_MPMQ_MIN_SPARE_DAEMONS 7 /* Min # of spare daemons */ 00142 #define AP_MPMQ_MIN_SPARE_THREADS 8 /* Min # of spare threads */ 00143 #define AP_MPMQ_MAX_SPARE_DAEMONS 9 /* Max # of spare daemons */ 00144 #define AP_MPMQ_MAX_SPARE_THREADS 10 /* Max # of spare threads */ 00145 #define AP_MPMQ_MAX_REQUESTS_DAEMON 11 /* Max # of requests per daemon */ 00146 #define AP_MPMQ_MAX_DAEMONS 12 /* Max # of daemons by config */ 00147 #define AP_MPMQ_MPM_STATE 13 /* starting, running, stopping */ 00148 #define AP_MPMQ_IS_ASYNC 14 /* MPM can process async connections */ 00149 00157 AP_DECLARE(apr_status_t) ap_mpm_query(int query_code, int *result); 00158 00159 /* Defining GPROF when compiling uses the moncontrol() function to 00160 * disable gprof profiling in the parent, and enable it only for 00161 * request processing in children (or in one_process mode). It's 00162 * absolutely required to get useful gprof results under linux 00163 * because the profile itimers and such are disabled across a 00164 * fork(). It's probably useful elsewhere as well. 00165 */ 00166 #ifdef GPROF 00167 extern void moncontrol(int); 00168 #define AP_MONCONTROL(x) moncontrol(x) 00169 #else 00170 #define AP_MONCONTROL(x) 00171 #endif 00172 00173 #if AP_ENABLE_EXCEPTION_HOOK 00174 typedef struct ap_exception_info_t { 00175 int sig; 00176 pid_t pid; 00177 } ap_exception_info_t; 00178 00179 AP_DECLARE_HOOK(int,fatal_exception,(ap_exception_info_t *ei)) 00180 #endif /*AP_ENABLE_EXCEPTION_HOOK*/ 00181 00182 #endif 00183