1 /* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements. See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License. You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 /* The purpose of this file is to store the code that MOST mpm's will need
18 * this does not mean a function only goes into this file if every MPM needs
19 * it. It means that if a function is needed by more than one MPM, and
20 * future maintenance would be served by making the code common, then the
21 * function belongs here.
23 * This is going in src/main because it is not platform specific, it is
24 * specific to multi-process servers, but NOT to Unix. Which is why it
25 * does not belong in src/os/unix
30 * @brief Multi-Processing Modules functions
32 * @defgroup APACHE_MPM Multi-Processing Modules
37 #ifndef APACHE_MPM_COMMON_H
38 #define APACHE_MPM_COMMON_H
40 #include "ap_config.h"
42 #if APR_HAVE_NETINET_TCP_H
43 #include <netinet/tcp.h> /* for TCP_NODELAY */
52 /* The maximum length of the queue of pending connections, as defined
53 * by listen(2). Under some systems, it should be increased if you
54 * are experiencing a heavy TCP SYN flood attack.
56 * It defaults to 511 instead of 512 because some systems store it
57 * as an 8-bit datatype; 512 truncated to 8-bits is 0, while 511 is
60 #ifndef DEFAULT_LISTENBACKLOG
61 #define DEFAULT_LISTENBACKLOG 511
64 /* Signal used to gracefully restart */
65 #define AP_SIG_GRACEFUL SIGUSR1
67 /* Signal used to gracefully restart (without SIG prefix) */
68 #define AP_SIG_GRACEFUL_SHORT USR1
70 /* Signal used to gracefully restart (as a quoted string) */
71 #define AP_SIG_GRACEFUL_STRING "SIGUSR1"
73 /* Signal used to gracefully stop */
74 #define AP_SIG_GRACEFUL_STOP SIGWINCH
76 /* Signal used to gracefully stop (without SIG prefix) */
77 #define AP_SIG_GRACEFUL_STOP_SHORT WINCH
79 /* Signal used to gracefully stop (as a quoted string) */
80 #define AP_SIG_GRACEFUL_STOP_STRING "SIGWINCH"
83 * Make sure all child processes that have been spawned by the parent process
84 * have died. This includes process registered as "other_children".
85 * @warning This is only defined if the MPM defines
86 * AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
87 * @param terminate Either 1 or 0. If 1, send the child processes SIGTERM
88 * each time through the loop. If 0, give the process time to die
89 * on its own before signalling it.
90 * @tip This function requires that some macros are defined by the MPM: <pre>
91 * MPM_CHILD_PID -- Get the pid from the specified spot in the scoreboard
92 * MPM_NOTE_CHILD_KILLED -- Note the child died in the scoreboard
94 * @tip The MPM child processes which are reclaimed are those listed
95 * in the scoreboard as well as those currently registered via
96 * ap_register_extra_mpm_process().
98 #ifdef AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
99 void ap_reclaim_child_processes(int terminate);
103 * Catch any child processes that have been spawned by the parent process
104 * which have exited. This includes processes registered as "other_children".
105 * @warning This is only defined if the MPM defines
106 * AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
107 * @tip This function requires that some macros are defined by the MPM: <pre>
108 * MPM_CHILD_PID -- Get the pid from the specified spot in the scoreboard
109 * MPM_NOTE_CHILD_KILLED -- Note the child died in the scoreboard
111 * @tip The MPM child processes which are relieved are those listed
112 * in the scoreboard as well as those currently registered via
113 * ap_register_extra_mpm_process().
115 #ifdef AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
116 void ap_relieve_child_processes(void);
120 * Tell ap_reclaim_child_processes() and ap_relieve_child_processes() about
121 * an MPM child process which has no entry in the scoreboard.
122 * @warning This is only defined if the MPM defines
123 * AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
124 * @param pid The process id of an MPM child process which should be
125 * reclaimed when ap_reclaim_child_processes() is called.
126 * @tip If an extra MPM child process terminates prior to calling
127 * ap_reclaim_child_processes(), remove it from the list of such processes
128 * by calling ap_unregister_extra_mpm_process().
130 #ifdef AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
131 void ap_register_extra_mpm_process(pid_t pid);
135 * Unregister an MPM child process which was previously registered by a
136 * call to ap_register_extra_mpm_process().
137 * @warning This is only defined if the MPM defines
138 * AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
139 * @param pid The process id of an MPM child process which no longer needs to
141 * @return 1 if the process was found and removed, 0 otherwise
143 #ifdef AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
144 int ap_unregister_extra_mpm_process(pid_t pid);
148 * Safely signal an MPM child process, if the process is in the
149 * current process group. Otherwise fail.
150 * @param pid the process id of a child process to signal
151 * @param sig the signal number to send
152 * @return APR_SUCCESS if signal is sent, otherwise an error as per kill(3);
153 * APR_EINVAL is returned if passed either an invalid (< 1) pid, or if
154 * the pid is not in the current process group
156 #ifdef AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
157 apr_status_t ap_mpm_safe_kill(pid_t pid, int sig);
161 * Determine if any child process has died. If no child process died, then
162 * this process sleeps for the amount of time specified by the MPM defined
163 * macro SCOREBOARD_MAINTENANCE_INTERVAL.
164 * @param status The return code if a process has died
165 * @param ret The process id of the process that died
166 * @param p The pool to allocate out of
168 #ifdef AP_MPM_WANT_WAIT_OR_TIMEOUT
169 void ap_wait_or_timeout(apr_exit_why_e *status, int *exitcode, apr_proc_t *ret,
174 * Log why a child died to the error log, if the child died without the
175 * parent signalling it.
176 * @param pid The child that has died
177 * @param status The status returned from ap_wait_or_timeout
178 * @return 0 on success, APEXIT_CHILDFATAL if MPM should terminate
180 #ifdef AP_MPM_WANT_PROCESS_CHILD_STATUS
181 int ap_process_child_status(apr_proc_t *pid, apr_exit_why_e why, int status);
184 #if defined(TCP_NODELAY) && !defined(MPE) && !defined(TPF)
186 * Turn off the nagle algorithm for the specified socket. The nagle algorithm
187 * says that we should delay sending partial packets in the hopes of getting
188 * more data. There are bad interactions between persistent connections and
189 * Nagle's algorithm that have severe performance penalties.
190 * @param s The socket to disable nagle for.
192 void ap_sock_disable_nagle(apr_socket_t *s);
194 #define ap_sock_disable_nagle(s) /* NOOP */
199 * Convert a username to a numeric ID
200 * @param name The name to convert
201 * @return The user id corresponding to a name
202 * @fn uid_t ap_uname2id(const char *name)
204 AP_DECLARE(uid_t) ap_uname2id(const char *name);
209 * Convert a group name to a numeric ID
210 * @param name The name to convert
211 * @return The group id corresponding to a name
212 * @fn gid_t ap_gname2id(const char *name)
214 AP_DECLARE(gid_t) ap_gname2id(const char *name);
217 #define AP_MPM_HARD_LIMITS_FILE APACHE_MPM_DIR "/mpm_default.h"
219 #ifdef AP_MPM_USES_POD
221 typedef struct ap_pod_t ap_pod_t;
230 * Open the pipe-of-death. The pipe of death is used to tell all child
231 * processes that it is time to die gracefully.
232 * @param p The pool to use for allocating the pipe
234 AP_DECLARE(apr_status_t) ap_mpm_pod_open(apr_pool_t *p, ap_pod_t **pod);
237 * Check the pipe to determine if the process has been signalled to die.
239 AP_DECLARE(apr_status_t) ap_mpm_pod_check(ap_pod_t *pod);
242 * Close the pipe-of-death
244 AP_DECLARE(apr_status_t) ap_mpm_pod_close(ap_pod_t *pod);
247 * Write data to the pipe-of-death, signalling that one child process
249 * @param p The pool to use when allocating any required structures.
251 AP_DECLARE(apr_status_t) ap_mpm_pod_signal(ap_pod_t *pod);
254 * Write data to the pipe-of-death, signalling that all child process
256 * @param p The pool to use when allocating any required structures.
257 * @param num The number of child processes to kill
259 AP_DECLARE(void) ap_mpm_pod_killpg(ap_pod_t *pod, int num);
263 * These data members are common to all mpms. Each new mpm
264 * should either use the appropriate ap_mpm_set_* function
265 * in their command table or create their own for custom or
266 * OS specific needs. These should work for most.
270 * The maximum number of requests each child thread or
271 * process handles before dying off
273 #ifdef AP_MPM_WANT_SET_MAX_REQUESTS
274 extern int ap_max_requests_per_child;
275 const char *ap_mpm_set_max_requests(cmd_parms *cmd, void *dummy,
280 * The filename used to store the process id.
282 #ifdef AP_MPM_WANT_SET_PIDFILE
283 extern const char *ap_pid_fname;
284 const char *ap_mpm_set_pidfile(cmd_parms *cmd, void *dummy,
289 * The name of lockfile used when Apache needs to lock the accept() call.
291 #ifdef AP_MPM_WANT_SET_LOCKFILE
292 extern const char *ap_lock_fname;
293 const char *ap_mpm_set_lockfile(cmd_parms *cmd, void *dummy,
298 * The system mutex implementation to use for the accept mutex.
300 #ifdef AP_MPM_WANT_SET_ACCEPT_LOCK_MECH
301 extern apr_lockmech_e ap_accept_lock_mech;
302 const char *ap_mpm_set_accept_lock_mech(cmd_parms *cmd, void *dummy,
307 * Set the scorboard file.
309 #ifdef AP_MPM_WANT_SET_SCOREBOARD
310 const char *ap_mpm_set_scoreboard(cmd_parms *cmd, void *dummy,
315 * The directory that the server changes directory to dump core.
317 #ifdef AP_MPM_WANT_SET_COREDUMPDIR
318 extern char ap_coredump_dir[MAX_STRING_LEN];
319 extern int ap_coredumpdir_configured;
320 const char *ap_mpm_set_coredumpdir(cmd_parms *cmd, void *dummy,
325 * Set the timeout period for a graceful shutdown.
327 #ifdef AP_MPM_WANT_SET_GRACEFUL_SHUTDOWN
328 extern int ap_graceful_shutdown_timeout;
329 const char *ap_mpm_set_graceful_shutdown(cmd_parms *cmd, void *dummy,
331 #define AP_GRACEFUL_SHUTDOWN_TIMEOUT_COMMAND \
332 AP_INIT_TAKE1("GracefulShutdownTimeout", ap_mpm_set_graceful_shutdown, NULL, \
333 RSRC_CONF, "Maximum time in seconds to wait for child " \
334 "processes to complete transactions during shutdown")
338 #ifdef AP_MPM_WANT_SIGNAL_SERVER
339 int ap_signal_server(int *, apr_pool_t *);
340 void ap_mpm_rewrite_args(process_rec *);
343 #ifdef AP_MPM_WANT_SET_MAX_MEM_FREE
344 extern apr_uint32_t ap_max_mem_free;
345 extern const char *ap_mpm_set_max_mem_free(cmd_parms *cmd, void *dummy,
349 #ifdef AP_MPM_WANT_SET_STACKSIZE
350 extern apr_size_t ap_thread_stacksize;
351 extern const char *ap_mpm_set_thread_stacksize(cmd_parms *cmd, void *dummy,
355 #ifdef AP_MPM_WANT_FATAL_SIGNAL_HANDLER
356 extern apr_status_t ap_fatal_signal_setup(server_rec *s, apr_pool_t *pconf);
357 extern apr_status_t ap_fatal_signal_child_setup(server_rec *s);
360 #if AP_ENABLE_EXCEPTION_HOOK
361 extern const char *ap_mpm_set_exception_hook(cmd_parms *cmd, void *dummy,
365 AP_DECLARE_HOOK(int,monitor,(apr_pool_t *p))
367 /* register modules that undertake to manage system security */
368 AP_DECLARE(int) ap_sys_privileges_handlers(int inc);
369 AP_DECLARE_HOOK(int, drop_privileges, (apr_pool_t * pchild, server_rec * s))
375 #endif /* !APACHE_MPM_COMMON_H */