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04fd4abf90
I added a few more fixes, and there are still more that might need a doxygen expert. PR: 48061 Submitted by: Brad Hards Reviewed by: poirier git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@830527 13f79535-47bb-0310-9956-ffa450edef68
198 lines
8.5 KiB
C
198 lines
8.5 KiB
C
/* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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* @file ap_mpm.h
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* @brief Apache Multi-Processing Module library
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*
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* @defgroup APACHE_CORE_MPM Multi-Processing Module library
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* @ingroup APACHE_CORE
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* @{
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*/
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#ifndef AP_MPM_H
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#define AP_MPM_H
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#include "apr_thread_proc.h"
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#include "httpd.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*
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The MPM, "multi-processing model" provides an abstraction of the
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interface with the OS for distributing incoming connections to
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threads/process for processing. http_main invokes the MPM, and
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the MPM runs until a shutdown/restart has been indicated.
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The MPM calls out to the apache core via the ap_process_connection
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function when a connection arrives.
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The MPM may or may not be multithreaded. In the event that it is
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multithreaded, at any instant it guarantees a 1:1 mapping of threads
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ap_process_connection invocations.
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Note: In the future it will be possible for ap_process_connection
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to return to the MPM prior to finishing the entire connection; and
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the MPM will proceed with asynchronous handling for the connection;
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in the future the MPM may call ap_process_connection again -- but
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does not guarantee it will occur on the same thread as the first call.
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The MPM further guarantees that no asynchronous behaviour such as
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longjmps and signals will interfere with the user code that is
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invoked through ap_process_connection. The MPM may reserve some
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signals for its use (i.e. SIGUSR1), but guarantees that these signals
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are ignored when executing outside the MPM code itself. (This
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allows broken user code that does not handle EINTR to function
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properly.)
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The suggested server restart and stop behaviour will be "graceful".
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However the MPM may choose to terminate processes when the user
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requests a non-graceful restart/stop. When this occurs, the MPM kills
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all threads with extreme prejudice, and destroys the pchild pool.
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User cleanups registered in the pchild apr_pool_t will be invoked at
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this point. (This can pose some complications, the user cleanups
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are asynchronous behaviour not unlike longjmp/signal... but if the
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admin is asking for a non-graceful shutdown, how much effort should
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we put into doing it in a nice way?)
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unix/posix notes:
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- The MPM does not set a SIGALRM handler, user code may use SIGALRM.
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But the preferred method of handling timeouts is to use the
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timeouts provided by the BUFF abstraction.
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- The proper setting for SIGPIPE is SIG_IGN, if user code changes it
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for any of their own processing, it must be restored to SIG_IGN
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prior to executing or returning to any apache code.
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TODO: add SIGPIPE debugging check somewhere to make sure it's SIG_IGN
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*/
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/**
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* Pass control to the MPM for steady-state processing. It is responsible
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* for controlling the parent and child processes. It will run until a
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* restart/shutdown is indicated.
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* @param pconf the configuration pool, reset before the config file is read
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* @param plog the log pool, reset after the config file is read
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* @param server_conf the global server config.
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* @return DONE for shutdown OK otherwise.
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*/
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AP_DECLARE_HOOK(int, mpm, (apr_pool_t *pconf, apr_pool_t *plog, server_rec *server_conf))
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/**
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* Spawn a process with privileges that another module has requested
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* @param r The request_rec of the current request
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* @param newproc The resulting process handle.
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* @param progname The program to run
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* @param args the arguments to pass to the new program. The first
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* one should be the program name.
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* @param env The new environment apr_table_t for the new process. This
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* should be a list of NULL-terminated strings.
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* @param attr the procattr we should use to determine how to create the new
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* process
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* @param p The pool to use.
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*/
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AP_DECLARE(apr_status_t) ap_os_create_privileged_process(
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const request_rec *r,
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apr_proc_t *newproc,
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const char *progname,
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const char * const *args,
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const char * const *env,
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apr_procattr_t *attr,
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apr_pool_t *p);
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/* Subtypes/Values for AP_MPMQ_IS_THREADED and AP_MPMQ_IS_FORKED */
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#define AP_MPMQ_NOT_SUPPORTED 0 /* This value specifies whether */
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/* an MPM is capable of */
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/* threading or forking. */
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#define AP_MPMQ_STATIC 1 /* This value specifies whether */
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/* an MPM is using a static # */
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/* threads or daemons. */
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#define AP_MPMQ_DYNAMIC 2 /* This value specifies whether */
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/* an MPM is using a dynamic # */
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/* threads or daemons. */
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/* Values returned for AP_MPMQ_MPM_STATE */
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#define AP_MPMQ_STARTING 0
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#define AP_MPMQ_RUNNING 1
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#define AP_MPMQ_STOPPING 2
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#define AP_MPMQ_MAX_DAEMON_USED 1 /* Max # of daemons used so far */
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#define AP_MPMQ_IS_THREADED 2 /* MPM can do threading */
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#define AP_MPMQ_IS_FORKED 3 /* MPM can do forking */
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#define AP_MPMQ_HARD_LIMIT_DAEMONS 4 /* The compiled max # daemons */
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#define AP_MPMQ_HARD_LIMIT_THREADS 5 /* The compiled max # threads */
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#define AP_MPMQ_MAX_THREADS 6 /* # of threads/child by config */
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#define AP_MPMQ_MIN_SPARE_DAEMONS 7 /* Min # of spare daemons */
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#define AP_MPMQ_MIN_SPARE_THREADS 8 /* Min # of spare threads */
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#define AP_MPMQ_MAX_SPARE_DAEMONS 9 /* Max # of spare daemons */
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#define AP_MPMQ_MAX_SPARE_THREADS 10 /* Max # of spare threads */
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#define AP_MPMQ_MAX_REQUESTS_DAEMON 11 /* Max # of requests per daemon */
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#define AP_MPMQ_MAX_DAEMONS 12 /* Max # of daemons by config */
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#define AP_MPMQ_MPM_STATE 13 /* starting, running, stopping */
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#define AP_MPMQ_IS_ASYNC 14 /* MPM can process async connections */
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#define AP_MPMQ_GENERATION 15 /* MPM generation */
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#define AP_MPMQ_HAS_SERF 16 /* MPM can drive serf internally */
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/**
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* Query a property of the current MPM.
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* @param query_code One of APM_MPMQ_*
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* @param result A location to place the result of the query
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* @return APR_EGENERAL if an mpm-query hook has not been registered;
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* APR_SUCCESS or APR_ENOTIMPL otherwise
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* @remark The MPM doesn't register the implementing hook until the
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* register_hooks hook is called, so modules cannot use ap_mpm_query()
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* until after that point.
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* @fn int ap_mpm_query(int query_code, int *result)
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*/
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AP_DECLARE(apr_status_t) ap_mpm_query(int query_code, int *result);
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typedef void (ap_mpm_callback_fn_t)(void *baton);
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/* only added support in the Event MPM.... check for APR_ENOTIMPL */
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AP_DECLARE(apr_status_t) ap_mpm_register_timed_callback(apr_time_t t,
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ap_mpm_callback_fn_t *cbfn,
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void *baton);
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/* Defining GPROF when compiling uses the moncontrol() function to
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* disable gprof profiling in the parent, and enable it only for
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* request processing in children (or in one_process mode). It's
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* absolutely required to get useful gprof results under linux
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* because the profile itimers and such are disabled across a
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* fork(). It's probably useful elsewhere as well.
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*/
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#ifdef GPROF
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extern void moncontrol(int);
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#define AP_MONCONTROL(x) moncontrol(x)
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#else
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#define AP_MONCONTROL(x)
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#endif
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#if AP_ENABLE_EXCEPTION_HOOK
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typedef struct ap_exception_info_t {
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int sig;
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pid_t pid;
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} ap_exception_info_t;
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AP_DECLARE_HOOK(int,fatal_exception,(ap_exception_info_t *ei))
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#endif /*AP_ENABLE_EXCEPTION_HOOK*/
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#ifdef __cplusplus
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}
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#endif
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#endif
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/** @} */
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