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/* $Id: thread.c,v 1.4 2001-05-23 17:56:35 rjkaes Exp $
*
* Handles the creation/destruction of the various threads required for
* processing incoming connections.
*
* Copyright (C) 2000 Robert James Kaes (rjkaes@flarenet.com)
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2, or (at your option) any
* later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include "tinyproxy.h"
#include "log.h"
#include "reqs.h"
#include "sock.h"
#include "thread.h"
static int listenfd;
static socklen_t addrlen;
/*
* Stores the internal data needed for each thread (connection)
*/
struct thread_s {
pthread_t tid;
enum { T_EMPTY, T_WAITING, T_CONNECTED } status;
unsigned int connects;
};
/*
* A pointer to an array of threads. A certain number of threads are
* created when the program is started.
*/
static struct thread_s *thread_ptr;
static pthread_mutex_t mlock = PTHREAD_MUTEX_INITIALIZER;
struct thread_config_s {
unsigned int maxclients, maxrequestsperchild;
unsigned int maxspareservers, minspareservers, startservers;
} thread_config;
static unsigned int servers_waiting; /* servers waiting for a connection */
static pthread_mutex_t servers_mutex = PTHREAD_MUTEX_INITIALIZER;
#define SERVER_INC() do { \
pthread_mutex_lock(&servers_mutex); \
servers_waiting++; \
pthread_mutex_unlock(&servers_mutex); \
} while (0)
#define SERVER_DEC() do { \
pthread_mutex_lock(&servers_mutex); \
servers_waiting--; \
pthread_mutex_unlock(&servers_mutex); \
} while (0)
/*
* Set the configuration values for the various thread related settings.
*/
int thread_configure(thread_config_t type, unsigned int val)
{
switch (type) {
case THREAD_MAXCLIENTS:
thread_config.maxclients = val;
break;
case THREAD_MAXSPARESERVERS:
thread_config.maxspareservers = val;
break;
case THREAD_MINSPARESERVERS:
thread_config.minspareservers = val;
break;
case THREAD_STARTSERVERS:
thread_config.startservers = val;
break;
case THREAD_MAXREQUESTSPERCHILD:
thread_config.maxrequestsperchild = val;
break;
default:
DEBUG2("Invalid type (%d)", type);
return -1;
}
return 0;
}
/*
* This is the main (per thread) loop.
*/
static void *thread_main(void *arg)
{
int connfd;
struct sockaddr *cliaddr;
socklen_t clilen;
struct thread_s *ptr;
ptr = (struct thread_s *)arg;
cliaddr = malloc(addrlen);
if (!cliaddr) {
log(LOG_ERR, "Could not allocate memory");
return NULL;
}
for ( ; ; ) {
clilen = addrlen;
pthread_mutex_lock(&mlock);
connfd = accept(listenfd, cliaddr, &clilen);
pthread_mutex_unlock(&mlock);
ptr->status = T_CONNECTED;
SERVER_DEC();
handle_connection(connfd);
close(connfd);
if (thread_config.maxrequestsperchild != 0)
ptr->connects++;
if (ptr->connects > thread_config.maxrequestsperchild) {
ptr->status = T_EMPTY;
return NULL;
} else {
ptr->status = T_WAITING;
SERVER_INC();
}
}
}
/*
* Create the initial pool of threads.
*/
int thread_pool_create(void)
{
unsigned int i;
if (thread_config.maxclients == 0) {
log(LOG_ERR, "You must set MaxClients to a value greater than 0");
return -1;
}
if (thread_config.startservers == 0) {
log(LOG_ERR, "You must set StartServers to a value greate than 0");
return -1;
}
thread_ptr = calloc(thread_config.maxclients, sizeof(struct thread_s));
if (!thread_ptr)
return -1;
if (thread_config.startservers > thread_config.maxclients) {
log(LOG_WARNING, "Can not start more than 'MaxClients' servers. Starting %d servers", thread_config.maxclients);
thread_config.startservers = thread_config.maxclients;
}
for (i = 0; i < thread_config.startservers; i++) {
thread_ptr[i].status = T_WAITING;
servers_waiting++;
pthread_create(&thread_ptr[i].tid, NULL, &thread_main, &thread_ptr[i]);
}
for (i = thread_config.startservers; i < thread_config.maxclients; i++) {
thread_ptr[i].status = T_EMPTY;
thread_ptr[i].connects = 0;
}
return 0;
}
/*
* Keep the proper number of servers running. This is the birth and death
* of the servers. It monitors this at least once a second.
*/
int thread_main_loop(void)
{
int i;
/* If there are not enough spare servers, create more */
if (servers_waiting < thread_config.minspareservers) {
for (i = 0; i < thread_config.maxclients; i++) {
if (thread_ptr[i].status == T_EMPTY) {
pthread_create(&thread_ptr[i].tid, NULL, &thread_main, &thread_ptr[i]);
thread_ptr[i].status = T_WAITING;
thread_ptr[i].connects = 0;
SERVER_INC();
log(LOG_NOTICE, "Created a new thread.");
break;
}
}
} else if (servers_waiting > thread_config.maxspareservers) {
for (i = 0; i < thread_config.maxclients; i++) {
if (thread_ptr[i].status == T_WAITING) {
pthread_join(thread_ptr[i].tid, NULL);
SERVER_DEC();
thread_ptr[i].status = T_EMPTY;
log(LOG_NOTICE, "Killed off a thread.");
break;
}
}
}
return 0;
}
inline int thread_listening_sock(unsigned int port)
{
listenfd = listen_sock(port, &addrlen);
return listenfd;
}
inline void thread_close_sock(void)
{
close(listenfd);
}
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