mpm_common.h revision 0cb6873985efbf0cc9644114925df6baa4b32d5a
/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* The purpose of this file is to store the code that MOST mpm's will need
* this does not mean a function only goes into this file if every MPM needs
* it. It means that if a function is needed by more than one MPM, and
* future maintenance would be served by making the code common, then the
* function belongs here.
*
* specific to multi-process servers, but NOT to Unix. Which is why it
*/
/**
* @file mpm_common.h
* @brief Multi-Processing Modules functions
*
* @defgroup APACHE_MPM Multi-Processing Modules
* @ingroup APACHE
* @{
*/
#ifndef APACHE_MPM_COMMON_H
#define APACHE_MPM_COMMON_H
#include "ap_config.h"
#include "ap_mpm.h"
#endif
#include "apr_proc_mutex.h"
#ifdef __cplusplus
extern "C" {
#endif
/* The maximum length of the queue of pending connections, as defined
* by listen(2). Under some systems, it should be increased if you
* are experiencing a heavy TCP SYN flood attack.
*
* It defaults to 511 instead of 512 because some systems store it
* as an 8-bit datatype; 512 truncated to 8-bits is 0, while 511 is
* 255 when truncated.
*/
#ifndef DEFAULT_LISTENBACKLOG
#define DEFAULT_LISTENBACKLOG 511
#endif
/* Signal used to gracefully restart */
#define AP_SIG_GRACEFUL SIGUSR1
/* Signal used to gracefully restart (without SIG prefix) */
#define AP_SIG_GRACEFUL_SHORT USR1
/* Signal used to gracefully restart (as a quoted string) */
#define AP_SIG_GRACEFUL_STRING "SIGUSR1"
/* Signal used to gracefully stop */
#define AP_SIG_GRACEFUL_STOP SIGWINCH
/* Signal used to gracefully stop (without SIG prefix) */
#define AP_SIG_GRACEFUL_STOP_SHORT WINCH
/* Signal used to gracefully stop (as a quoted string) */
#define AP_SIG_GRACEFUL_STOP_STRING "SIGWINCH"
/**
* Make sure all child processes that have been spawned by the parent process
* have died. This includes process registered as "other_children".
* @param terminate Either 1 or 0. If 1, send the child processes SIGTERM
* each time through the loop. If 0, give the process time to die
* on its own before signalling it.
* @note This function requires that a hook is implemented by the MPM: <pre>
* mpm_note_child_killed -- Note the child died in the scoreboard
* </pre>
*
* @note The MPM child processes which are reclaimed are those listed
* in the scoreboard as well as those currently registered via
* ap_register_extra_mpm_process().
*/
void ap_reclaim_child_processes(int terminate);
/**
* Catch any child processes that have been spawned by the parent process
* which have exited. This includes processes registered as "other_children".
*
* @note This function requires that a hook is implemented by the MPM: <pre>
* mpm_note_child_killed -- Note the child died in the scoreboard
* </pre>
*
* @note The MPM child processes which are relieved are those listed
* in the scoreboard as well as those currently registered via
* ap_register_extra_mpm_process().
*/
void ap_relieve_child_processes(void);
/**
* Tell ap_reclaim_child_processes() and ap_relieve_child_processes() about
* an MPM child process which has no entry in the scoreboard.
* @param pid The process id of an MPM child process which should be
* reclaimed when ap_reclaim_child_processes() is called.
*
* @note If an extra MPM child process terminates prior to calling
* ap_reclaim_child_processes(), remove it from the list of such processes
* by calling ap_unregister_extra_mpm_process().
*/
/**
* Unregister an MPM child process which was previously registered by a
* call to ap_register_extra_mpm_process().
* @param pid The process id of an MPM child process which no longer needs to
* be reclaimed.
* @return 1 if the process was found and removed, 0 otherwise
*/
/**
* Safely signal an MPM child process, if the process is in the
* current process group. Otherwise fail.
* @param pid the process id of a child process to signal
* @param sig the signal number to send
* @return APR_SUCCESS if signal is sent, otherwise an error as per kill(3);
* APR_EINVAL is returned if passed either an invalid (< 1) pid, or if
* the pid is not in the current process group
*/
/**
* Determine if any child process has died. If no child process died, then
* this process sleeps for the amount of time specified by the MPM defined
* macro SCOREBOARD_MAINTENANCE_INTERVAL.
* @param status The return code if a process has died
* @param exitcode The returned exit status of the child, if a child process
* dies, or the signal that caused the child to die.
* @param ret The process id of the process that died
* @param p The pool to allocate out of
* @param s The server_rec to pass
*/
apr_pool_t *p, server_rec *s);
/**
* Log why a child died to the error log, if the child died without the
* parent signalling it.
* @param pid The child that has died
* @param why The return code of the child process
* @param status The status returned from ap_wait_or_timeout
* @return 0 on success, APEXIT_CHILDFATAL if MPM should terminate
*/
#if defined(TCP_NODELAY)
/**
* Turn off the nagle algorithm for the specified socket. The nagle algorithm
* says that we should delay sending partial packets in the hopes of getting
* more data. There are bad interactions between persistent connections and
* Nagle's algorithm that have severe performance penalties.
* @param s The socket to disable nagle for.
*/
void ap_sock_disable_nagle(apr_socket_t *s);
#else
#define ap_sock_disable_nagle(s) /* NOOP */
#endif
#ifdef HAVE_GETPWNAM
/**
* Convert a username to a numeric ID
* @param name The name to convert
* @return The user id corresponding to a name
* @fn uid_t ap_uname2id(const char *name)
*/
#endif
#ifdef HAVE_GETGRNAM
/**
* Convert a group name to a numeric ID
* @param name The name to convert
* @return The group id corresponding to a name
* @fn gid_t ap_gname2id(const char *name)
*/
#endif
struct ap_pod_t {
apr_pool_t *p;
};
/**
* Open the pipe-of-death. The pipe of death is used to tell all child
* processes that it is time to die gracefully.
* @param p The pool to use for allocating the pipe
* @param pod the pipe-of-death that is created.
*/
/**
* Check the pipe to determine if the process has been signalled to die.
*/
/**
* Close the pipe-of-death
*
* @param pod the pipe-of-death to close.
*/
/**
* Write data to the pipe-of-death, signalling that one child process
* should die.
* @param pod the pipe-of-death to write to.
*/
/**
* Write data to the pipe-of-death, signalling that all child process
* should die.
* @param pod The pipe-of-death to write to.
* @param num The number of child processes to kill
*/
/*
* These data members are common to all mpms. Each new mpm
* should either use the appropriate ap_mpm_set_* function
* in their command table or create their own for custom or
* OS specific needs. These should work for most.
*/
/**
* The maximum number of requests each child thread or
* process handles before dying off
*/
extern int ap_max_requests_per_child;
const char *arg);
/**
* The filename used to store the process id.
*/
extern const char *ap_pid_fname;
const char *arg);
/*
* The directory that the server changes directory to dump core.
*/
extern char ap_coredump_dir[MAX_STRING_LEN];
extern int ap_coredumpdir_configured;
const char *arg);
/**
* Set the timeout period for a graceful shutdown.
*/
extern int ap_graceful_shutdown_timeout;
const char *arg);
#define AP_GRACEFUL_SHUTDOWN_TIMEOUT_COMMAND \
RSRC_CONF, "Maximum time in seconds to wait for child " \
"processes to complete transactions during shutdown")
int ap_signal_server(int *, apr_pool_t *);
void ap_mpm_rewrite_args(process_rec *);
extern apr_uint32_t ap_max_mem_free;
const char *arg);
extern apr_size_t ap_thread_stacksize;
const char *arg);
const char *arg);
#endif
/* register modules that undertake to manage system security */
/* implement the ap_mpm_query() function
* The MPM should return OK+APR_ENOTIMPL for any unimplemented query codes;
* modules which intercede for specific query codes should DECLINE for others.
*/
/* child specified by index has been killed */
/* register the specified callback */
/* get MPM name (e.g., "prefork" or "event") */
AP_DECLARE_HOOK(const char *,mpm_get_name,(void))
/* mutex type string for accept mutex, if any; MPMs should use the
* same mutex type for ease of configuration
*/
#define ap_accept_mutex_type "mpm-accept"
#ifdef __cplusplus
}
#endif
#endif /* !APACHE_MPM_COMMON_H */
/** @} */