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
28 #ifndef APACHE_MPM_COMMON_H
29 #define APACHE_MPM_COMMON_H
31 #include "ap_config.h"
33 #if APR_HAVE_NETINET_TCP_H
34 #include <netinet/tcp.h> /* for TCP_NODELAY */
44 * @package Multi-Processing Modules functions
47 /* The maximum length of the queue of pending connections, as defined
48 * by listen(2). Under some systems, it should be increased if you
49 * are experiencing a heavy TCP SYN flood attack.
51 * It defaults to 511 instead of 512 because some systems store it
52 * as an 8-bit datatype; 512 truncated to 8-bits is 0, while 511 is
55 #ifndef DEFAULT_LISTENBACKLOG
56 #define DEFAULT_LISTENBACKLOG 511
60 * Make sure all child processes that have been spawned by the parent process
61 * have died. This includes process registered as "other_children".
62 * @warning This is only defined if the MPM defines
63 * AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
64 * @param terminate Either 1 or 0. If 1, send the child processes SIGTERM
65 * each time through the loop. If 0, give the process time to die
66 * on its own before signalling it.
67 * @tip This function requires that some macros are defined by the MPM: <pre>
68 * MPM_CHILD_PID -- Get the pid from the specified spot in the scoreboard
69 * MPM_NOTE_CHILD_KILLED -- Note the child died in the scoreboard
71 * @tip The MPM child processes which are reclaimed are those listed
72 * in the scoreboard as well as those currently registered via
73 * ap_register_extra_mpm_process().
75 #ifdef AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
76 void ap_reclaim_child_processes(int terminate);
80 * Tell ap_reclaim_child_processes() about an MPM child process which has no
81 * entry in the scoreboard.
82 * @warning This is only defined if the MPM defines
83 * AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
84 * @param pid The process id of an MPM child process which should be
85 * reclaimed when ap_reclaim_child_processes() is called.
86 * @tip If an extra MPM child process terminates prior to calling
87 * ap_reclaim_child_processes(), remove it from the list of such processes
88 * by calling ap_unregister_extra_mpm_process().
90 #ifdef AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
91 void ap_register_extra_mpm_process(pid_t pid);
95 * Unregister an MPM child process which was previously registered by a
96 * call to ap_register_extra_mpm_process().
97 * @warning This is only defined if the MPM defines
98 * AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
99 * @param pid The process id of an MPM child process which no longer needs to
101 * @return 1 if the process was found and removed, 0 otherwise
103 #ifdef AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
104 int ap_unregister_extra_mpm_process(pid_t pid);
108 * Determine if any child process has died. If no child process died, then
109 * this process sleeps for the amount of time specified by the MPM defined
110 * macro SCOREBOARD_MAINTENANCE_INTERVAL.
111 * @param status The return code if a process has died
112 * @param ret The process id of the process that died
113 * @param p The pool to allocate out of
115 #ifdef AP_MPM_WANT_WAIT_OR_TIMEOUT
116 void ap_wait_or_timeout(apr_exit_why_e *status, int *exitcode, apr_proc_t *ret,
121 * Log why a child died to the error log, if the child died without the
122 * parent signalling it.
123 * @param pid The child that has died
124 * @param status The status returned from ap_wait_or_timeout
125 * @return 0 on success, APEXIT_CHILDFATAL if MPM should terminate
127 #ifdef AP_MPM_WANT_PROCESS_CHILD_STATUS
128 int ap_process_child_status(apr_proc_t *pid, apr_exit_why_e why, int status);
131 #if defined(TCP_NODELAY) && !defined(MPE) && !defined(TPF)
133 * Turn off the nagle algorithm for the specified socket. The nagle algorithm
134 * says that we should delay sending partial packets in the hopes of getting
135 * more data. There are bad interactions between persistent connections and
136 * Nagle's algorithm that have severe performance penalties.
137 * @param s The socket to disable nagle for.
139 void ap_sock_disable_nagle(apr_socket_t *s);
141 #define ap_sock_disable_nagle(s) /* NOOP */
146 * Convert a username to a numeric ID
147 * @param name The name to convert
148 * @return The user id corresponding to a name
149 * @deffunc uid_t ap_uname2id(const char *name)
151 AP_DECLARE(uid_t) ap_uname2id(const char *name);
156 * Convert a group name to a numeric ID
157 * @param name The name to convert
158 * @return The group id corresponding to a name
159 * @deffunc gid_t ap_gname2id(const char *name)
161 AP_DECLARE(gid_t) ap_gname2id(const char *name);
164 #define AP_MPM_HARD_LIMITS_FILE APACHE_MPM_DIR "/mpm_default.h"
166 #ifdef AP_MPM_USES_POD
168 typedef struct ap_pod_t ap_pod_t;
178 * Open the pipe-of-death. The pipe of death is used to tell all child
179 * processes that it is time to die gracefully.
180 * @param p The pool to use for allocating the pipe
182 AP_DECLARE(apr_status_t) ap_mpm_pod_open(apr_pool_t *p, ap_pod_t **pod);
185 * Check the pipe to determine if the process has been signalled to die.
187 AP_DECLARE(apr_status_t) ap_mpm_pod_check(ap_pod_t *pod);
190 * Close the pipe-of-death
192 AP_DECLARE(apr_status_t) ap_mpm_pod_close(ap_pod_t *pod);
195 * Write data to the pipe-of-death, signalling that one child process
197 * @param p The pool to use when allocating any required structures.
199 AP_DECLARE(apr_status_t) ap_mpm_pod_signal(ap_pod_t *pod);
202 * Write data to the pipe-of-death, signalling that all child process
204 * @param p The pool to use when allocating any required structures.
205 * @param num The number of child processes to kill
207 AP_DECLARE(void) ap_mpm_pod_killpg(ap_pod_t *pod, int num);
211 * These data members are common to all mpms. Each new mpm
212 * should either use the appropriate ap_mpm_set_* function
213 * in their command table or create their own for custom or
214 * OS specific needs. These should work for most.
218 * The maximum number of requests each child thread or
219 * process handles before dying off
221 #ifdef AP_MPM_WANT_SET_MAX_REQUESTS
222 extern int ap_max_requests_per_child;
223 const char *ap_mpm_set_max_requests(cmd_parms *cmd, void *dummy,
228 * The filename used to store the process id.
230 #ifdef AP_MPM_WANT_SET_PIDFILE
231 extern const char *ap_pid_fname;
232 const char *ap_mpm_set_pidfile(cmd_parms *cmd, void *dummy,
237 * The name of lockfile used when Apache needs to lock the accept() call.
239 #ifdef AP_MPM_WANT_SET_LOCKFILE
240 extern const char *ap_lock_fname;
241 const char *ap_mpm_set_lockfile(cmd_parms *cmd, void *dummy,
246 * The system mutex implementation to use for the accept mutex.
248 #ifdef AP_MPM_WANT_SET_ACCEPT_LOCK_MECH
249 extern apr_lockmech_e ap_accept_lock_mech;
250 extern const char ap_valid_accept_mutex_string[];
251 const char *ap_mpm_set_accept_lock_mech(cmd_parms *cmd, void *dummy,
256 * Set the scorboard file.
258 #ifdef AP_MPM_WANT_SET_SCOREBOARD
259 const char *ap_mpm_set_scoreboard(cmd_parms *cmd, void *dummy,
264 * The directory that the server changes directory to dump core.
266 #ifdef AP_MPM_WANT_SET_COREDUMPDIR
267 extern char ap_coredump_dir[MAX_STRING_LEN];
268 extern int ap_coredumpdir_configured;
269 const char *ap_mpm_set_coredumpdir(cmd_parms *cmd, void *dummy,
273 #ifdef AP_MPM_WANT_SIGNAL_SERVER
274 int ap_signal_server(int *, apr_pool_t *);
275 void ap_mpm_rewrite_args(process_rec *);
278 #ifdef AP_MPM_WANT_SET_MAX_MEM_FREE
279 extern apr_uint32_t ap_max_mem_free;
280 extern const char *ap_mpm_set_max_mem_free(cmd_parms *cmd, void *dummy,
284 #ifdef AP_MPM_WANT_FATAL_SIGNAL_HANDLER
285 extern apr_status_t ap_fatal_signal_setup(server_rec *s, apr_pool_t *pconf);
286 extern apr_status_t ap_fatal_signal_child_setup(server_rec *s);
289 #if AP_ENABLE_EXCEPTION_HOOK
290 extern const char *ap_mpm_set_exception_hook(cmd_parms *cmd, void *dummy,
298 #endif /* !APACHE_MPM_COMMON_H */