1 /* ====================================================================
2 * The Apache Software License, Version 1.1
4 * Copyright (c) 2000-2004 The Apache Software Foundation. All rights
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in
16 * the documentation and/or other materials provided with the
19 * 3. The end-user documentation included with the redistribution,
20 * if any, must include the following acknowledgment:
21 * "This product includes software developed by the
22 * Apache Software Foundation (http://www.apache.org/)."
23 * Alternately, this acknowledgment may appear in the software itself,
24 * if and wherever such third-party acknowledgments normally appear.
26 * 4. The names "Apache" and "Apache Software Foundation" must
27 * not be used to endorse or promote products derived from this
28 * software without prior written permission. For written
29 * permission, please contact apache@apache.org.
31 * 5. Products derived from this software may not be called "Apache",
32 * nor may "Apache" appear in their name, without prior written
33 * permission of the Apache Software Foundation.
35 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
36 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
37 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
38 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
39 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
41 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
42 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
43 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
44 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
45 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
47 * ====================================================================
49 * This software consists of voluntary contributions made by many
50 * individuals on behalf of the Apache Software Foundation. For more
51 * information on the Apache Software Foundation, please see
52 * <http://www.apache.org/>.
58 #include "apr_thread_proc.h"
61 * @package Multi-Processing Module library
65 The MPM, "multi-processing model" provides an abstraction of the
66 interface with the OS for distributing incoming connections to
67 threads/process for processing. http_main invokes the MPM, and
68 the MPM runs until a shutdown/restart has been indicated.
69 The MPM calls out to the apache core via the ap_process_connection
70 function when a connection arrives.
72 The MPM may or may not be multithreaded. In the event that it is
73 multithreaded, at any instant it guarantees a 1:1 mapping of threads
74 ap_process_connection invocations.
76 Note: In the future it will be possible for ap_process_connection
77 to return to the MPM prior to finishing the entire connection; and
78 the MPM will proceed with asynchronous handling for the connection;
79 in the future the MPM may call ap_process_connection again -- but
80 does not guarantee it will occur on the same thread as the first call.
82 The MPM further guarantees that no asynchronous behaviour such as
83 longjmps and signals will interfere with the user code that is
84 invoked through ap_process_connection. The MPM may reserve some
85 signals for its use (i.e. SIGUSR1), but guarantees that these signals
86 are ignored when executing outside the MPM code itself. (This
87 allows broken user code that does not handle EINTR to function
90 The suggested server restart and stop behaviour will be "graceful".
91 However the MPM may choose to terminate processes when the user
92 requests a non-graceful restart/stop. When this occurs, the MPM kills
93 all threads with extreme prejudice, and destroys the pchild pool.
94 User cleanups registered in the pchild apr_pool_t will be invoked at
95 this point. (This can pose some complications, the user cleanups
96 are asynchronous behaviour not unlike longjmp/signal... but if the
97 admin is asking for a non-graceful shutdown, how much effort should
98 we put into doing it in a nice way?)
101 - The MPM does not set a SIGALRM handler, user code may use SIGALRM.
102 But the preferred method of handling timeouts is to use the
103 timeouts provided by the BUFF abstraction.
104 - The proper setting for SIGPIPE is SIG_IGN, if user code changes it
105 for any of their own processing, it must be restored to SIG_IGN
106 prior to executing or returning to any apache code.
107 TODO: add SIGPIPE debugging check somewhere to make sure it's SIG_IGN
111 * This is the function that MPMs must create. This function is responsible
112 * for controlling the parent and child processes. It will run until a
113 * restart/shutdown is indicated.
114 * @param pconf the configuration pool, reset before the config file is read
115 * @param plog the log pool, reset after the config file is read
116 * @param server_conf the global server config.
117 * @return 1 for shutdown 0 otherwise.
118 * @deffunc int ap_mpm_run(apr_pool_t *pconf, apr_pool_t *plog, server_rec *server_conf)
120 AP_DECLARE(int) ap_mpm_run(apr_pool_t *pconf, apr_pool_t *plog, server_rec *server_conf);
123 * predicate indicating if a graceful stop has been requested ...
124 * used by the connection loop
125 * @return 1 if a graceful stop has been requested, 0 otherwise
126 * @deffunc int ap_graceful_stop_signalled(*void)
128 AP_DECLARE(int) ap_graceful_stop_signalled(void);
131 * Spawn a process with privileges that another module has requested
132 * @param r The request_rec of the current request
133 * @param newproc The resulting process handle.
134 * @param progname The program to run
135 * @param const_args the arguments to pass to the new program. The first
136 * one should be the program name.
137 * @param env The new environment apr_table_t for the new process. This
138 * should be a list of NULL-terminated strings.
139 * @param attr the procattr we should use to determine how to create the new
141 * @param p The pool to use.
143 AP_DECLARE(apr_status_t) ap_os_create_privileged_process(
144 const request_rec *r,
146 const char *progname,
147 const char * const *args,
148 const char * const *env,
149 apr_procattr_t *attr,
152 /* Subtypes/Values for AP_MPMQ_IS_THREADED and AP_MPMQ_IS_FORKED */
153 #define AP_MPMQ_NOT_SUPPORTED 0 /* This value specifies whether */
154 /* an MPM is capable of */
155 /* threading or forking. */
156 #define AP_MPMQ_STATIC 1 /* This value specifies whether */
157 /* an MPM is using a static # */
158 /* threads or daemons. */
159 #define AP_MPMQ_DYNAMIC 2 /* This value specifies whether */
160 /* an MPM is using a dynamic # */
161 /* threads or daemons. */
163 /* Values returned for AP_MPMQ_MPM_STATE */
164 #define AP_MPMQ_STARTING 0
165 #define AP_MPMQ_RUNNING 1
166 #define AP_MPMQ_STOPPING 2
168 #define AP_MPMQ_MAX_DAEMON_USED 1 /* Max # of daemons used so far */
169 #define AP_MPMQ_IS_THREADED 2 /* MPM can do threading */
170 #define AP_MPMQ_IS_FORKED 3 /* MPM can do forking */
171 #define AP_MPMQ_HARD_LIMIT_DAEMONS 4 /* The compiled max # daemons */
172 #define AP_MPMQ_HARD_LIMIT_THREADS 5 /* The compiled max # threads */
173 #define AP_MPMQ_MAX_THREADS 6 /* # of threads/child by config */
174 #define AP_MPMQ_MIN_SPARE_DAEMONS 7 /* Min # of spare daemons */
175 #define AP_MPMQ_MIN_SPARE_THREADS 8 /* Min # of spare threads */
176 #define AP_MPMQ_MAX_SPARE_DAEMONS 9 /* Max # of spare daemons */
177 #define AP_MPMQ_MAX_SPARE_THREADS 10 /* Max # of spare threads */
178 #define AP_MPMQ_MAX_REQUESTS_DAEMON 11 /* Max # of requests per daemon */
179 #define AP_MPMQ_MAX_DAEMONS 12 /* Max # of daemons by config */
180 #define AP_MPMQ_MPM_STATE 13 /* starting, running, stopping */
183 * Query a property of the current MPM.
184 * @param query_code One of APM_MPMQ_*
185 * @param result A location to place the result of the query
186 * @return APR_SUCCESS or APR_ENOTIMPL
187 * @deffunc int ap_mpm_query(int query_code, int *result)
189 AP_DECLARE(apr_status_t) ap_mpm_query(int query_code, int *result);
191 /* Defining GPROF when compiling uses the moncontrol() function to
192 * disable gprof profiling in the parent, and enable it only for
193 * request processing in children (or in one_process mode). It's
194 * absolutely required to get useful gprof results under linux
195 * because the profile itimers and such are disabled across a
196 * fork(). It's probably useful elsewhere as well.
199 extern void moncontrol(int);
200 #define AP_MONCONTROL(x) moncontrol(x)
202 #define AP_MONCONTROL(x)
205 #if AP_ENABLE_EXCEPTION_HOOK
206 typedef struct ap_exception_info_t {
209 } ap_exception_info_t;
211 AP_DECLARE_HOOK(int,fatal_exception,(ap_exception_info_t *ei))
212 #endif /*AP_ENABLE_EXCEPTION_HOOK*/