tinyproxy now uses a pool of threads to handle connections. All the work

for creating new threads, deleting old thread, and generally managing the
pool is done here.

2 files changed, 250 insertions, 0 deletions

diff --git a/src/thread.c b/src/thread.c
new file mode 100644
index 0000000..6e5d0fb
--- /dev/null
+++ b/src/thread.c
@@ -0,0 +1,214 @@
+/* $Id: thread.c,v 1.1 2000-09-12 00:07:44 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;
+struct thread_s {
+	pthread_t tid;
+	enum { T_EMPTY, T_WAITING, T_CONNECTED } status;
+};
+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;
+static pthread_cond_t servers_cond = PTHREAD_COND_INITIALIZER;
+
+#define LOCK_SERVERS()	 pthread_mutex_lock(&servers_mutex)
+#define UNLOCK_SERVERS() pthread_mutex_unlock(&servers_mutex)
+
+/*
+ * 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);
+
+		LOCK_SERVERS();
+		ptr->status = T_CONNECTED;
+		servers_waiting--;
+		UNLOCK_SERVERS();
+
+		handle_connection(connfd);
+		close(connfd);
+
+		LOCK_SERVERS();
+		ptr->status = T_WAITING;
+		servers_waiting++;
+		UNLOCK_SERVERS();
+	}
+}
+/*
+ * 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;
+	}
+
+	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;
+	struct timeval tv;
+	struct timespec ts;
+
+	while (config.quit == FALSE) {
+		/* Wait for one of the threads to signal */
+		pthread_mutex_lock(&servers_mutex);
+		while (config.quit == FALSE
+		       && servers_waiting < thread_config.maxspareservers
+		       && servers_waiting > thread_config.minspareservers) {
+			if (gettimeofday(&tv, NULL) < 0) {
+				return -1;
+			}
+			ts.tv_sec = tv.tv_sec + 1;
+			ts.tv_nsec = tv.tv_usec * 1000;
+			pthread_cond_timedwait(&servers_cond, &servers_mutex, &ts);
+		}
+
+		if (config.quit == TRUE)
+			return 0;
+
+		/* 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;
+					servers_waiting++;
+					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);
+					servers_waiting--;
+					thread_ptr[i].status = T_EMPTY;
+					log(LOG_NOTICE, "Killed off a thread.");
+					break;
+				}
+			}
+		}
+		pthread_mutex_unlock(&servers_mutex);
+	}
+	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);
+}
diff --git a/src/thread.h b/src/thread.h
new file mode 100644
index 0000000..aea5382
--- /dev/null
+++ b/src/thread.h
@@ -0,0 +1,36 @@
+/* $Id: thread.h,v 1.1 2000-09-12 00:07:44 rjkaes Exp $
+ *
+ * See 'thread.c' for more information.
+ *
+ * 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.
+ */
+
+#ifndef _TINYPROXY_THREAD_H_
+#define _TINYPROXY_THREAD_H_
+
+typedef enum {
+	THREAD_MAXCLIENTS,
+	THREAD_MAXSPARESERVERS,
+	THREAD_MINSPARESERVERS,
+	THREAD_STARTSERVERS,
+	THREAD_MAXREQUESTSPERCHILD
+} thread_config_t;
+
+extern int thread_pool_create(void);
+extern int thread_listening_sock(unsigned int port);
+extern void thread_close_sock(void);
+extern int thread_main_loop(void);
+
+extern int thread_configure(thread_config_t type, unsigned int val);
+
+#endif