+struct web_client *single_threaded_clients[FD_SETSIZE];
+
+static inline int single_threaded_link_client(struct web_client *w, fd_set *ifds, fd_set *ofds, fd_set *efds, int *max) {
+ if(unlikely(w->obsolete || w->dead || (!w->wait_receive && !w->wait_send)))
+ return 1;
+
+ if(unlikely(w->ifd < 0 || w->ifd >= FD_SETSIZE || w->ofd < 0 || w->ofd >= FD_SETSIZE)) {
+ error("%llu: invalid file descriptor, ifd = %d, ofd = %d (required 0 <= fd < FD_SETSIZE (%d)", w->id, w->ifd, w->ofd, FD_SETSIZE);
+ return 1;
+ }
+
+ FD_SET(w->ifd, efds);
+ if(unlikely(*max < w->ifd)) *max = w->ifd;
+
+ if(unlikely(w->ifd != w->ofd)) {
+ if(*max < w->ofd) *max = w->ofd;
+ FD_SET(w->ofd, efds);
+ }
+
+ if(w->wait_receive) FD_SET(w->ifd, ifds);
+ if(w->wait_send) FD_SET(w->ofd, ofds);
+
+ single_threaded_clients[w->ifd] = w;
+ single_threaded_clients[w->ofd] = w;
+
+ return 0;
+}
+
+static inline int single_threaded_unlink_client(struct web_client *w, fd_set *ifds, fd_set *ofds, fd_set *efds) {
+ FD_CLR(w->ifd, efds);
+ if(unlikely(w->ifd != w->ofd)) FD_CLR(w->ofd, efds);
+
+ if(w->wait_receive) FD_CLR(w->ifd, ifds);
+ if(w->wait_send) FD_CLR(w->ofd, ofds);
+
+ single_threaded_clients[w->ifd] = NULL;
+ single_threaded_clients[w->ofd] = NULL;
+
+ if(unlikely(w->obsolete || w->dead || (!w->wait_receive && !w->wait_send)))
+ return 1;
+
+ return 0;
+}
+
+void *socket_listen_main_single_threaded(void *ptr) {
+ struct netdata_static_thread *static_thread = (struct netdata_static_thread *)ptr;
+
+ web_server_mode = WEB_SERVER_MODE_SINGLE_THREADED;
+
+ info("Single-threaded WEB SERVER thread created with task id %d", gettid());
+
+ struct web_client *w;
+ int retval;
+
+ if(pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, NULL) != 0)
+ error("Cannot set pthread cancel type to DEFERRED.");
+
+ if(pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL) != 0)
+ error("Cannot set pthread cancel state to ENABLE.");
+
+ if(!listen_fds_count)
+ fatal("LISTENER: no listen sockets available.");
+
+ size_t i;
+ for(i = 0; i < FD_SETSIZE ; i++)
+ single_threaded_clients[i] = NULL;
+
+ fd_set ifds, ofds, efds, rifds, rofds, refds;
+ FD_ZERO (&ifds);
+ FD_ZERO (&ofds);
+ FD_ZERO (&efds);
+ int fdmax = 0;
+
+ for(i = 0; i < listen_fds_count ; i++) {
+ if (listen_fds[i] < 0 || listen_fds[i] >= FD_SETSIZE)
+ fatal("LISTENER: Listen socket %d is not ready, or invalid.", listen_fds[i]);
+
+ info("Listening on '%s'", (listen_fds_names[i])?listen_fds_names[i]:"UNKNOWN");
+
+ FD_SET(listen_fds[i], &ifds);
+ FD_SET(listen_fds[i], &efds);
+ if(fdmax < listen_fds[i])
+ fdmax = listen_fds[i];
+ }
+
+ for(;;) {
+ debug(D_WEB_CLIENT_ACCESS, "LISTENER: single threaded web server waiting (fdmax = %d)...", fdmax);
+
+ struct timeval tv = { .tv_sec = 1, .tv_usec = 0 };
+ rifds = ifds;
+ rofds = ofds;
+ refds = efds;
+ retval = select(fdmax+1, &rifds, &rofds, &refds, &tv);
+
+ if(unlikely(retval == -1)) {
+ error("LISTENER: select() failed.");
+ continue;
+ }
+ else if(likely(retval)) {
+ debug(D_WEB_CLIENT_ACCESS, "LISTENER: got something.");
+
+ for(i = 0; i < listen_fds_count ; i++) {
+ if (FD_ISSET(listen_fds[i], &rifds)) {
+ debug(D_WEB_CLIENT_ACCESS, "LISTENER: new connection.");
+ w = web_client_create(listen_fds[i]);
+ if (single_threaded_link_client(w, &ifds, &ofds, &ifds, &fdmax) != 0) {
+ web_client_free(w);
+ }
+ }
+ }
+
+ for(i = 0 ; i <= (size_t)fdmax ; i++) {
+ if(likely(!FD_ISSET(i, &rifds) && !FD_ISSET(i, &rofds) && !FD_ISSET(i, &refds)))
+ continue;
+
+ w = single_threaded_clients[i];
+ if(unlikely(!w))
+ continue;
+
+ if(unlikely(single_threaded_unlink_client(w, &ifds, &ofds, &efds) != 0)) {
+ web_client_free(w);
+ continue;
+ }
+
+ if (unlikely(FD_ISSET(w->ifd, &refds) || FD_ISSET(w->ofd, &refds))) {
+ web_client_free(w);
+ continue;
+ }
+
+ if (unlikely(w->wait_receive && FD_ISSET(w->ifd, &rifds))) {
+ if (unlikely(web_client_receive(w) < 0)) {
+ web_client_free(w);
+ continue;
+ }
+
+ if (w->mode != WEB_CLIENT_MODE_FILECOPY) {
+ debug(D_WEB_CLIENT, "%llu: Processing received data.", w->id);
+ web_client_process_request(w);
+ }
+ }
+
+ if (unlikely(w->wait_send && FD_ISSET(w->ofd, &rofds))) {
+ if (unlikely(web_client_send(w) < 0)) {
+ debug(D_WEB_CLIENT, "%llu: Cannot send data to client. Closing client.", w->id);
+ web_client_free(w);
+ continue;
+ }
+ }
+
+ if(unlikely(single_threaded_link_client(w, &ifds, &ofds, &efds, &fdmax) != 0)) {
+ web_client_free(w);
+ }
+ }
+ }
+ else {
+ debug(D_WEB_CLIENT_ACCESS, "LISTENER: single threaded web server timeout.");
+#ifdef NETDATA_INTERNAL_CHECKS
+ log_allocations();
+#endif
+ }
+ }
+
+ debug(D_WEB_CLIENT, "LISTENER: exit!");
+ close_listen_sockets();
+
+ static_thread->enabled = 0;
+ pthread_exit(NULL);
+ return NULL;
+}