scoreboard.h revision 8d6907fd72855909a91eadeba1b1f20ab6f23926
/* ====================================================================
* Copyright (c) 1995-1999 The Apache Group. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the Apache Group
* for use in the Apache HTTP server project (http://www.apache.org/)."
*
* 4. The names "Apache Server" and "Apache Group" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Group.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the Apache Group
* for use in the Apache HTTP server project (http://www.apache.org/)."
*
* THIS SOFTWARE IS PROVIDED BY THE APACHE GROUP ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE APACHE GROUP OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Group and was originally based
* on public domain software written at the National Center for
* Supercomputing Applications, University of Illinois, Urbana-Champaign.
* For more information on the Apache Group and the Apache HTTP server
* project, please see <http://www.apache.org/>.
*
*/
#ifndef APACHE_SCOREBOARD_H
#define APACHE_SCOREBOARD_H
#ifdef __cplusplus
extern "C" {
#endif
#ifndef WIN32
#ifdef TPF
#include <time.h>
#else
#include <sys/times.h>
#endif /* TPF */
#endif
#ifdef HAVE_SYS_TIMES_H
#include <sys/times.h>
#endif
/* Scoreboard info on a process is, for now, kept very brief ---
* just status value and pid (the latter so that the caretaker process
* can properly update the scoreboard when a process dies). We may want
* to eventually add a separate set of long_score structures which would
* give, for each process, the number of requests serviced, and info on
* the current, or most recent, request.
*
* Status values:
*/
#define SERVER_DEAD 0
#define SERVER_STARTING 1 /* Server Starting up */
#define SERVER_READY 2 /* Waiting for connection (or accept() lock) */
#define SERVER_BUSY_READ 3 /* Reading a client request */
#define SERVER_BUSY_WRITE 4 /* Processing a client request */
#define SERVER_BUSY_KEEPALIVE 5 /* Waiting for more requests via keepalive */
#define SERVER_BUSY_LOG 6 /* Logging the request */
#define SERVER_BUSY_DNS 7 /* Looking up a hostname */
#define SERVER_GRACEFUL 8 /* server is gracefully finishing request */
#define SERVER_NUM_STATUS 9 /* number of status settings */
/* A "virtual time" is simply a counter that indicates that a child is
* making progress. The parent checks up on each child, and when they have
* made progress it resets the last_rtime element. But when the child hasn't
* made progress in a time that's roughly timeout_len seconds long, it is
* sent a SIGALRM.
*
* vtime is an optimization that is used only when the scoreboard is in
* shared memory (it's not easy/feasible to do it in a scoreboard file).
* The essential observation is that timeouts rarely occur, the vast majority
* of hits finish before any timeout happens. So it really sucks to have to
* ask the operating system to set up and destroy alarms many times during
* a request.
*/
typedef unsigned vtime_t;
/* Type used for generation indicies. Startup and every restart cause a
* new generation of children to be spawned. Children within the same
* generation share the same configuration information -- pointers to stuff
* created at config time in the parent are valid across children. For
* example, the vhostrec pointer in the scoreboard below is valid in all
* children of the same generation.
*
* The safe way to access the vhost pointer is like this:
*
* short_score *ss = pointer to whichver slot is interesting;
* parent_score *ps = pointer to whichver slot is interesting;
* server_rec *vh = ss->vhostrec;
*
* if (ps->generation != ap_my_generation) {
* vh = NULL;
* }
*
* then if vh is not NULL it's valid in this child.
*
* This avoids various race conditions around restarts.
*/
typedef int ap_generation_t;
/* stuff which the children generally write, and the parent mainly reads */
typedef struct {
#ifdef OPTIMIZE_TIMEOUTS
vtime_t cur_vtime; /* the child's current vtime */
unsigned short timeout_len; /* length of the timeout */
#endif
unsigned char status;
unsigned long access_count;
unsigned long bytes_served;
unsigned long my_access_count;
unsigned long my_bytes_served;
unsigned long conn_bytes;
unsigned short conn_count;
#if !defined(HAVE_GETTIMEOFDAY)
clock_t start_time;
clock_t stop_time;
#else
struct timeval start_time;
struct timeval stop_time;
#endif
#ifdef HAVE_TIMES
struct tms times;
#endif
#ifndef OPTIMIZE_TIMEOUTS
time_t last_used;
#endif
char client[32]; /* Keep 'em small... */
char request[64]; /* We just want an idea... */
server_rec *vhostrec; /* What virtual host is being accessed? */
/* SEE ABOVE FOR SAFE USAGE! */
} short_score;
typedef struct {
ap_generation_t running_generation; /* the generation of children which
* should still be serving requests. */
} global_score;
/* stuff which the parent generally writes and the children rarely read */
typedef struct {
pid_t pid;
#ifdef OPTIMIZE_TIMEOUTS
time_t last_rtime; /* time(0) of the last change */
vtime_t last_vtime; /* the last vtime the parent has seen */
#endif
ap_generation_t generation; /* generation of this child */
} parent_score;
typedef struct {
short_score servers[HARD_SERVER_LIMIT];
parent_score parent[HARD_SERVER_LIMIT];
global_score global;
} scoreboard;
#define SCOREBOARD_SIZE sizeof(scoreboard)
#ifdef TPF
#define SCOREBOARD_NAME "SCOREBRD"
#define SCOREBOARD_FRAMES SCOREBOARD_SIZE/4095 + 1
#endif
API_EXPORT(void) ap_sync_scoreboard_image(void);
API_EXPORT(int) ap_exists_scoreboard_image(void);
API_VAR_EXPORT extern scoreboard *ap_scoreboard_image;
API_VAR_EXPORT extern ap_generation_t volatile ap_my_generation;
/* for time_process_request() in http_main.c */
#define START_PREQUEST 1
#define STOP_PREQUEST 2
#ifdef __cplusplus
}
#endif
#endif /* !APACHE_SCOREBOARD_H */