Add child_status hook for tracking creation/termination of MPM child

Changes with Apache 2.3.12

  *) Add child_status hook for tracking creation/termination of MPM child

     processes.  Add end_generation hook for notification when the last

     MPM child of a generation exits. [Jeff Trawick]

  *) mod_ldap: Make LDAPSharedCacheSize 0 create a non-shared-memory cache per

     process as opposed to disabling caching completely. This allows to use

     the non-shared-memory cache as a workaround for the shared memory cache

 * 20110329.1 (2.3.12-dev) Add ap_reserve_module_slots()/ap_reserve_module_slots_directive()

 *                         change AP_CORE_DECLARE to AP_DECLARE: ap_create_request_config()

 *                         change AP_DECLARE to AP_CORE_DECLARE: ap_register_log_hooks()

 * 20110329.2 (2.3.12-dev) Add child_status and end_generation hooks.

 */

#define MODULE_MAGIC_COOKIE 0x41503234UL /* "AP24" */

#ifndef MODULE_MAGIC_NUMBER_MAJOR

#define MODULE_MAGIC_NUMBER_MAJOR 20110329

#endif

#define MODULE_MAGIC_NUMBER_MINOR 1                    /* 0...n */

#define MODULE_MAGIC_NUMBER_MINOR 2                    /* 0...n */

/**

 * Determine if the server's current MODULE_MAGIC_NUMBER is at least a

#include "apr_thread_proc.h"

#include "httpd.h"

#include "scoreboard.h"

#ifdef __cplusplus

extern "C" {

                                                       ap_mpm_callback_fn_t *cbfn,

                                                       void *baton);

typedef enum mpm_child_status {

    MPM_CHILD_STARTED,

    MPM_CHILD_EXITED,

    MPM_CHILD_LOST_SLOT

} mpm_child_status;

/**

 * Allow a module to remain aware of MPM child process state changes,

 * along with the generation and scoreboard slot of the process changing

 * state.

 *

 * With some MPMs (event and worker), an active MPM child process may lose

 * its scoreboard slot if the child process is exiting and the scoreboard

 * slot is needed by other processes.  When this occurs, the hook will be

 * called with the MPM_CHILD_LOST_SLOT state.

 *

 * @param s The main server_rec.

 * @param pid The id of the MPM child process.

 * @param gen The server generation of that child process.

 * @param slot The scoreboard slot number, or -1.  It will be -1 when an

 * MPM child process exits, and that child had previously lost its

 * scoreboard slot.

 * @param state One of the mpm_child_status values.  Modules should ignore

 * unrecognized values.

 */

AP_DECLARE_HOOK(void,child_status,(server_rec *s, pid_t pid, ap_generation_t gen,

                                   int slot, mpm_child_status state))

/**

 * Allow a module to be notified when the last child process of a generation

 * exits.

 *

 * @param s The main server_rec.

 * @param gen The server generation which is now completely finished.

 */

AP_DECLARE_HOOK(void,end_generation,(server_rec *s, ap_generation_t gen))

/* Defining GPROF when compiling uses the moncontrol() function to

 * disable gprof profiling in the parent, and enable it only for

 * request processing in children (or in one_process mode).  It's

#include "ap_config.h"

#include "ap_mpm.h"

#include "scoreboard.h"

#if APR_HAVE_NETINET_TCP_H

#include <netinet/tcp.h>    /* for TCP_NODELAY */

 * ap_relieve_child_processes().  The callback function will be

 * called for each terminated child process.

 */

typedef void ap_reclaim_callback_fn_t(int childnum);

typedef void ap_reclaim_callback_fn_t(int childnum, pid_t pid,

                                      ap_generation_t gen);

/**

 * Make sure all child processes that have been spawned by the parent process

 * 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.

 * @param gen The generation of this MPM child process.

 *

 * @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().

 */

void ap_register_extra_mpm_process(pid_t pid);

void ap_register_extra_mpm_process(pid_t pid, ap_generation_t gen);

/**

 * 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.

 * @param old_gen Set to the server generation of the process, if found.

 * @return 1 if the process was found and removed, 0 otherwise

 */

int ap_unregister_extra_mpm_process(pid_t pid);

int ap_unregister_extra_mpm_process(pid_t pid, ap_generation_t *old_gen);

/**

 * Safely signal an MPM child process, if the process is in the

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);

/* core's implementation of child_status hook */

extern void ap_core_child_status(server_rec *s, pid_t pid, ap_generation_t gen,

                                 int slot, mpm_child_status status);

#if AP_ENABLE_EXCEPTION_HOOK

extern const char *ap_mpm_set_exception_hook(cmd_parms *cmd, void *dummy,

                                             const char *arg);

    APR_OPTIONAL_HOOK(proxy, create_req, core_create_proxy_req, NULL, NULL,

                      APR_HOOK_MIDDLE);

    ap_hook_pre_mpm(ap_create_scoreboard, NULL, NULL, APR_HOOK_MIDDLE);

    ap_hook_child_status(ap_core_child_status, NULL, NULL, APR_HOOK_MIDDLE);

    /* register the core's insert_filter hook and register core-provided

     * filters