mpm_common.h revision dd028aa8111afb6534fece555e8c2d408894671e
/* 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
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* 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.
*
* This is going in src/main because it is not platform specific, it is
* specific to multi-process servers, but NOT to Unix. Which is why it
* does not belong in src/os/unix
*/
/**
* @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"
#if APR_HAVE_NETINET_TCP_H
#include <netinet/tcp.h> /* for TCP_NODELAY */
#endif
#ifdef WIN32
/* XXX temporary mitigation for Windows; other non-Unix MPMs need this hack too
* include mpm.h to pick up the AP_MPM_NO_foo definitions
*/
#include "mpm.h"
#endif
#ifndef AP_MPM_NO_SET_ACCEPT_LOCK_MECH
#include "apr_proc_mutex.h"
#endif
#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".
* @warning This is only defined if the MPM defines
* AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
* @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.
* @tip This function requires that some macros are defined by the MPM: <pre>
* MPM_CHILD_PID -- Get the pid from the specified spot in the scoreboard
* MPM_NOTE_CHILD_KILLED -- Note the child died in the scoreboard
* </pre>
* @tip 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().
*/
#ifndef AP_MPM_NO_RECLAIM_CHILD_PROCESSES
void ap_reclaim_child_processes(int terminate);
#endif
/**
* Catch any child processes that have been spawned by the parent process
* which have exited. This includes processes registered as "other_children".
* @warning This is only defined if the MPM defines
* AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
* @tip This function requires that some macros are defined by the MPM: <pre>
* MPM_CHILD_PID -- Get the pid from the specified spot in the scoreboard
* MPM_NOTE_CHILD_KILLED -- Note the child died in the scoreboard
* </pre>
* @tip 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().
*/
#ifndef AP_MPM_NO_RECLAIM_CHILD_PROCESSES
void ap_relieve_child_processes(void);
#endif
/**
* Tell ap_reclaim_child_processes() and ap_relieve_child_processes() about
* an MPM child process which has no entry in the scoreboard.
* @warning This is only defined if the MPM defines
* AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
* @param pid The process id of an MPM child process which should be
* reclaimed when ap_reclaim_child_processes() is called.
* @tip 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().
*/
#ifndef AP_MPM_NO_RECLAIM_CHILD_PROCESSES
void ap_register_extra_mpm_process(pid_t pid);
#endif
/**
* Unregister an MPM child process which was previously registered by a
* call to ap_register_extra_mpm_process().
* @warning This is only defined if the MPM defines
* AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
* @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
*/
#ifndef AP_MPM_NO_RECLAIM_CHILD_PROCESSES
int ap_unregister_extra_mpm_process(pid_t pid);
#endif
/**
* 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
*/
#ifndef AP_MPM_NO_RECLAIM_CHILD_PROCESSES
apr_status_t ap_mpm_safe_kill(pid_t pid, int sig);
#endif
/**
* 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 ret The process id of the process that died
* @param p The pool to allocate out of
*/
#ifndef AP_MPM_NO_WAIT_OR_TIMEOUT
void ap_wait_or_timeout(apr_exit_why_e *status, int *exitcode, apr_proc_t *ret,
apr_pool_t *p);
#endif
/**
* 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 status The status returned from ap_wait_or_timeout
* @return 0 on success, APEXIT_CHILDFATAL if MPM should terminate
*/
#ifndef AP_MPM_NO_PROCESS_CHILD_STATUS
int ap_process_child_status(apr_proc_t *pid, apr_exit_why_e why, int status);
#endif
#if defined(TCP_NODELAY) && !defined(MPE) && !defined(TPF)
/**
* 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)
*/
AP_DECLARE(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)
*/
AP_DECLARE(gid_t) ap_gname2id(const char *name);
#endif
#define AP_MPM_HARD_LIMITS_FILE APACHE_MPM_DIR "/mpm_default.h"
#ifndef AP_MPM_NO_POD
typedef struct ap_pod_t ap_pod_t;
struct ap_pod_t {
apr_file_t *pod_in;
apr_file_t *pod_out;
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
*/
AP_DECLARE(apr_status_t) ap_mpm_pod_open(apr_pool_t *p, ap_pod_t **pod);
/**
* Check the pipe to determine if the process has been signalled to die.
*/
AP_DECLARE(apr_status_t) ap_mpm_pod_check(ap_pod_t *pod);
/**
* Close the pipe-of-death
*/
AP_DECLARE(apr_status_t) ap_mpm_pod_close(ap_pod_t *pod);
/**
* Write data to the pipe-of-death, signalling that one child process
* should die.
* @param p The pool to use when allocating any required structures.
*/
AP_DECLARE(apr_status_t) ap_mpm_pod_signal(ap_pod_t *pod);
/**
* Write data to the pipe-of-death, signalling that all child process
* should die.
* @param p The pool to use when allocating any required structures.
* @param num The number of child processes to kill
*/
AP_DECLARE(void) ap_mpm_pod_killpg(ap_pod_t *pod, int num);
#endif
/*
* 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
*/
#ifndef AP_MPM_NO_SET_MAX_REQUESTS
extern int ap_max_requests_per_child;
const char *ap_mpm_set_max_requests(cmd_parms *cmd, void *dummy,
const char *arg);
#endif
/**
* The filename used to store the process id.
*/
#ifndef AP_MPM_NO_SET_PIDFILE
extern const char *ap_pid_fname;
const char *ap_mpm_set_pidfile(cmd_parms *cmd, void *dummy,
const char *arg);
#endif
/**
* The name of lockfile used when Apache needs to lock the accept() call.
*/
#ifndef AP_MPM_NO_SET_LOCKFILE
extern const char *ap_lock_fname;
const char *ap_mpm_set_lockfile(cmd_parms *cmd, void *dummy,
const char *arg);
#endif
/**
* The system mutex implementation to use for the accept mutex.
*/
#ifndef AP_MPM_NO_SET_ACCEPT_LOCK_MECH
extern apr_lockmech_e ap_accept_lock_mech;
const char *ap_mpm_set_accept_lock_mech(cmd_parms *cmd, void *dummy,
const char *arg);
#endif
/*
* Set the scorboard file.
*/
#ifndef AP_MPM_NO_SET_SCOREBOARD
const char *ap_mpm_set_scoreboard(cmd_parms *cmd, void *dummy,
const char *arg);
#endif
/*
* The directory that the server changes directory to dump core.
*/
#ifndef AP_MPM_NO_SET_COREDUMPDIR
extern char ap_coredump_dir[MAX_STRING_LEN];
extern int ap_coredumpdir_configured;
const char *ap_mpm_set_coredumpdir(cmd_parms *cmd, void *dummy,
const char *arg);
#endif
/**
* Set the timeout period for a graceful shutdown.
*/
#ifndef AP_MPM_NO_SET_GRACEFUL_SHUTDOWN
extern int ap_graceful_shutdown_timeout;
const char *ap_mpm_set_graceful_shutdown(cmd_parms *cmd, void *dummy,
const char *arg);
#define AP_GRACEFUL_SHUTDOWN_TIMEOUT_COMMAND \
AP_INIT_TAKE1("GracefulShutdownTimeout", ap_mpm_set_graceful_shutdown, NULL, \
RSRC_CONF, "Maximum time in seconds to wait for child " \
"processes to complete transactions during shutdown")
#endif
#ifndef AP_MPM_NO_SIGNAL_SERVER
int ap_signal_server(int *, apr_pool_t *);
void ap_mpm_rewrite_args(process_rec *);
#endif
#ifndef AP_MPM_NO_SET_MAX_MEM_FREE
extern apr_uint32_t ap_max_mem_free;
extern const char *ap_mpm_set_max_mem_free(cmd_parms *cmd, void *dummy,
const char *arg);
#endif
#ifndef AP_MPM_NO_SET_STACKSIZE
extern apr_size_t ap_thread_stacksize;
extern const char *ap_mpm_set_thread_stacksize(cmd_parms *cmd, void *dummy,
const char *arg);
#endif
#ifndef AP_MPM_NO_FATAL_SIGNAL_HANDLER
extern apr_status_t ap_fatal_signal_setup(server_rec *s, apr_pool_t *pconf);
extern apr_status_t ap_fatal_signal_child_setup(server_rec *s);
#endif
#if AP_ENABLE_EXCEPTION_HOOK
extern const char *ap_mpm_set_exception_hook(cmd_parms *cmd, void *dummy,
const char *arg);
#endif
#ifndef AP_MPM_NO_CHILD_PID
extern pid_t ap_mpm_get_child_pid(int childnum);
extern pid_t ap_mpm_note_child_killed(int childnum);
#endif
AP_DECLARE_HOOK(int,monitor,(apr_pool_t *p))
/* register modules that undertake to manage system security */
AP_DECLARE(int) ap_sys_privileges_handlers(int inc);
AP_DECLARE_HOOK(int, drop_privileges, (apr_pool_t * pchild, server_rec * s))
/* pass control to the MPM */
AP_DECLARE_HOOK(int, mpm, (apr_pool_t *pconf, apr_pool_t *plog, server_rec *s));
/* implement the mpm query function */
AP_DECLARE_HOOK(apr_status_t, mpm_query, (int query_code, int *result));
/* get pid of child by index */
AP_DECLARE_HOOK(pid_t, mpm_get_child_pid, (int childnum));
/* child specified by index has been killed */
AP_DECLARE_HOOK(apr_status_t, mpm_note_child_killed, (int childnum));
/* register the specified callback */
AP_DECLARE_HOOK(apr_status_t, mpm_register_timed_callback,
(apr_time_t t, ap_mpm_callback_fn_t *cbfn, void *baton));
#ifdef __cplusplus
}
#endif
#endif /* !APACHE_MPM_COMMON_H */
/** @} */