multithreaded web server using poll()

1 files changed, 57 insertions, 42 deletions

diff --git a/src/web_client.c b/src/web_client.c
index 368a24b5c6..4477b8a4d3 100644
--- a/src/web_client.c
+++ b/src/web_client.c
@@ -16,6 +16,7 @@
 #include <pwd.h>
 #include <grp.h>
 #include <ctype.h>
+#include <poll.h>
 
 #include "common.h"
 #include "log.h"
@@ -90,7 +91,8 @@ struct web_client *web_client_create(int listener)
 				strcpy(w->client_ip, &w->client_ip[7]);
 				debug(D_WEB_CLIENT_ACCESS, "%llu: New IPv4 web client from %s port %s on socket %d.", w->id, w->client_ip, w->client_port, w->ifd);
 			}
-			debug(D_WEB_CLIENT_ACCESS, "%llu: New IPv6 web client from %s port %s on socket %d.", w->id, w->client_ip, w->client_port, w->ifd);
+			else
+				debug(D_WEB_CLIENT_ACCESS, "%llu: New IPv6 web client from %s port %s on socket %d.", w->id, w->client_ip, w->client_port, w->ifd);
 			break;
 
 		default:
@@ -2103,9 +2105,8 @@ void *web_client_main(void *ptr)
 		error("Cannot set pthread cancel state to ENABLE.");
 
 	struct web_client *w = ptr;
-	int retval;
-	fd_set ifds, ofds, efds;
-	int fdmax = 0;
+	struct pollfd fds[2], *ifd, *ofd;
+	int retval, fdmax = 0, timeout;
 
 	log_access("%llu: %s port %s connected on thread task id %d", w->id, w->client_ip, w->client_port, gettid());
 
@@ -2119,62 +2120,73 @@ void *web_client_main(void *ptr)
 			break;
 		}
 
-		FD_ZERO (&ifds);
-		FD_ZERO (&ofds);
-		FD_ZERO (&efds);
-
-		if(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);
+		if(unlikely(w->ifd < 0 || w->ofd < 0)) {
+			error("%llu: invalid file descriptor, ifd = %d, ofd = %d (required 0 <= fd", w->id, w->ifd, w->ofd);
 			break;
 		}
 
-		FD_SET(w->ifd, &efds);
+		if(w->ifd == w->ofd) {
+			fds[0].fd = w->ifd;
+			fds[0].events = 0;
+			fds[0].revents = 0;
 
-		if(w->ifd != w->ofd)
-			FD_SET(w->ofd, &efds);
+			if(w->wait_receive) fds[0].events += POLLIN;
+			if(w->wait_send)    fds[0].events += POLLOUT;
 
-		if (w->wait_receive) {
-			FD_SET(w->ifd, &ifds);
-			if(w->ifd > fdmax) fdmax = w->ifd;
-		}
+			fds[1].fd = -1;
+			fds[1].events = 0;
+			fds[1].revents = 0;
 
-		if (w->wait_send) {
-			FD_SET(w->ofd, &ofds);
-			if(w->ofd > fdmax) fdmax = w->ofd;
-		}
+			ifd = ofd = &fds[0];
 
-		debug(D_WEB_CLIENT, "%llu: Waiting socket async I/O for %s %s", w->id, w->wait_receive?"INPUT":"", w->wait_send?"OUTPUT":"");
-		struct timeval tv = { .tv_sec = web_client_timeout, .tv_usec = 0 };
-		retval = select(fdmax+1, &ifds, &ofds, &efds, &tv);
-
-		if(retval == -1) {
-			error("%llu: LISTENER: select() failed (input fd = %d, output fd = %d). Closing client.", w->id, w->ifd, w->ofd);
-			break;
+			fdmax = 1;
 		}
-		else if(!retval) {
-			// timeout
-			debug(D_WEB_CLIENT_ACCESS, "%llu: LISTENER: timeout.", w->id);
-			break;
+		else {
+			fds[0].fd = w->ifd;
+			fds[0].events = 0;
+			fds[0].revents = 0;
+			if(w->wait_receive) fds[0].events += POLLIN;
+			ifd = &fds[0];
+
+			fds[1].fd = w->ofd;
+			fds[1].events = 0;
+			fds[1].revents = 0;
+			if(w->wait_send)    fds[1].events += POLLOUT;
+			ofd = &fds[1];
+
+			fdmax = 2;
 		}
 
-		if(FD_ISSET(w->ifd, &efds)) {
-			debug(D_WEB_CLIENT_ACCESS, "%llu: Received error on input socket.", w->id);
+		debug(D_WEB_CLIENT, "%llu: Waiting socket async I/O for %s %s", w->id, w->wait_receive?"INPUT":"", w->wait_send?"OUTPUT":"");
+		errno = 0;
+		timeout = web_client_timeout * 1000;
+		retval = poll(fds, fdmax, timeout);
+
+		if(unlikely(retval == -1)) {
+			if(errno == EAGAIN || errno == EINTR) {
+				debug(D_WEB_CLIENT, "%llu: EAGAIN received.", w->id);
+				continue;
+			}
+
+			error("%llu: LISTENER: poll() failed (input fd = %d, output fd = %d). Closing client.", w->id, w->ifd, w->ofd);
 			break;
 		}
-
-		if(FD_ISSET(w->ofd, &efds)) {
-			debug(D_WEB_CLIENT_ACCESS, "%llu: Received error on output socket.", w->id);
+		else if(unlikely(!retval)) {
+			debug(D_WEB_CLIENT, "%llu: Timeout while waiting socket async I/O for %s %s", w->id, w->wait_receive?"INPUT":"", w->wait_send?"OUTPUT":"");
 			break;
 		}
 
-		if(w->wait_send && FD_ISSET(w->ofd, &ofds)) {
+		int used = 0;
+		if(w->wait_send && ofd->revents & POLLOUT) {
+			used++;
 			if(web_client_send(w) < 0) {
 				debug(D_WEB_CLIENT, "%llu: Cannot send data to client. Closing client.", w->id);
 				break;
 			}
 		}
 
-		if(w->wait_receive && FD_ISSET(w->ifd, &ifds)) {
+		if(w->wait_receive && (ifd->revents & POLLIN || ifd->revents & POLLPRI)) {
+			used++;
 			if(web_client_receive(w) < 0) {
 				debug(D_WEB_CLIENT, "%llu: Cannot receive data from client. Closing client.", w->id);
 				break;
@@ -2185,13 +2197,16 @@ void *web_client_main(void *ptr)
 				web_client_process(w);
 			}
 		}
+
+		if(unlikely(!used)) {
+			debug(D_WEB_CLIENT_ACCESS, "%llu: Received error on socket.", w->id);
+			break;
+		}
 	}
 
 	log_access("%llu: %s port %s disconnected from thread task id %d", w->id, w->client_ip, w->client_port, gettid());
 	debug(D_WEB_CLIENT, "%llu: done...", w->id);
 
-	web_client_reset(w);
-
 	// close the sockets/files now
 	// to free file descriptors
 	if(w->ifd == w->ofd) {
@@ -2199,7 +2214,7 @@ void *web_client_main(void *ptr)
 	}
 	else {
 		if(w->ifd != -1) close(w->ifd);
-		if(w->ofd != -1) close(w->ifd);
+		if(w->ofd != -1) close(w->ofd);
 	}
 	w->ifd = -1;
 	w->ofd = -1;