3 // This module handles the task of setting up a listening socket, accepting
4 // connections, and dispatching active connections onto a pool of worker
7 // Copyright (c) 1996-2022 by the citadel.org team
9 // This program is open source software. Use, duplication, or disclosure is subject to the GNU General Public License v3.
11 #include "webcit.h" // All other headers are included from this header.
13 int num_threads_executing = 1; // Number of worker threads currently bound to a connected client
14 int num_threads_existing = 1; // Total number of worker threads that exist right now
15 int is_https = 0; // Set to nonzero if we are running as an HTTPS server today.
16 static void *original_brk = NULL; // Remember the original program break so we can test for leaks
19 // Spawn an additional worker thread into the pool.
20 void spawn_another_worker_thread(int *pointer_to_master_socket) {
21 pthread_t th; // Thread descriptor
22 pthread_attr_t attr; // Thread attributes
24 // set attributes for the new thread
25 pthread_attr_init(&attr);
26 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
27 pthread_attr_setstacksize(&attr, 1048576); // Large stacks to prevent MIME parser crash on FreeBSD
29 // now create the thread
30 if (pthread_create(&th, &attr, (void *(*)(void *)) worker_entry, (void *) pointer_to_master_socket) != 0) {
31 syslog(LOG_WARNING, "Can't create thread: %s", strerror(errno));
34 ++num_threads_existing;
35 ++num_threads_executing;
38 // free up the attributes
39 pthread_attr_destroy(&attr);
43 // Entry point for worker threads
44 void worker_entry(int *pointer_to_master_socket) {
45 int master_socket = *pointer_to_master_socket;
47 int fail_this_transaction = 0;
48 struct client_handle ch;
51 // Each worker thread blocks on accept() while waiting for something to do.
52 // We don't have to worry about the "thundering herd" problem on modern kernels; for an explanation see
53 // https://stackoverflow.com/questions/2213779/does-the-thundering-herd-problem-exist-on-linux-anymore
54 memset(&ch, 0, sizeof ch);
58 --num_threads_executing;
59 syslog(LOG_DEBUG, "Additional memory allocated since startup: %d bytes", (int) (sbrk(0) - original_brk));
60 syslog(LOG_DEBUG, "Thread 0x%x calling accept() on master socket %d", (unsigned int) pthread_self(),
62 ch.sock = accept(master_socket, NULL, 0);
64 syslog(LOG_DEBUG, "accept() : %s", strerror(errno));
66 ++num_threads_executing;
67 syslog(LOG_DEBUG, "socket %d is awake , threads executing: %d , threads total: %d", ch.sock,
68 num_threads_executing, num_threads_existing);
69 } while ((master_socket > 0) && (ch.sock < 0));
71 // If all threads are executing, spawn more, up to the maximum
72 if ((num_threads_executing >= num_threads_existing) && (num_threads_existing <= MAX_WORKER_THREADS)) {
73 spawn_another_worker_thread(pointer_to_master_socket);
76 // We have a client. Do some work.
78 // Set the SO_REUSEADDR socket option
80 setsockopt(ch.sock, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
82 // If we are an HTTPS server, go crypto now.
85 if (ch.ssl_handle == NULL) {
86 fail_this_transaction = 1;
91 fdflags = fcntl(ch.sock, F_GETFL);
93 syslog(LOG_WARNING, "unable to get server socket flags! %s", strerror(errno));
97 // Perform an HTTP transaction...
98 if (fail_this_transaction == 0) {
99 perform_one_http_transaction(&ch);
102 // Shut down SSL/TLS if required...
106 // ...and close the socket.
107 //syslog(LOG_DEBUG, "Closing socket %d...", ch.sock);
108 //lingering_close(ch.sock);
110 syslog(LOG_DEBUG, "Closed socket %d.", ch.sock);
115 // Start up a TCP HTTP[S] server on the requested port
116 int webserver(char *webserver_interface, int webserver_port, int webserver_protocol) {
117 int master_socket = (-1);
118 original_brk = sbrk(0);
120 switch (webserver_protocol) {
122 syslog(LOG_DEBUG, "Starting HTTP server on %s:%d", webserver_interface, webserver_port);
123 master_socket = webcit_tcp_server(webserver_interface, webserver_port, 10);
125 case WEBSERVER_HTTPS:
126 syslog(LOG_DEBUG, "Starting HTTPS server on %s:%d", webserver_interface, webserver_port);
127 master_socket = webcit_tcp_server(webserver_interface, webserver_port, 10);
132 syslog(LOG_ERR, "unknown protocol");
136 if (master_socket < 1) {
137 syslog(LOG_ERR, "Unable to bind the web server listening socket");
141 syslog(LOG_INFO, "Listening on socket %d", master_socket);
142 signal(SIGPIPE, SIG_IGN);
144 worker_entry(&master_socket); // this thread becomes a worker