From: Tamás Földesi <tamas.foldesi@more.no>
Date: Tue, 30 Jun 2015 17:06:28 +0000 (+0200)
Subject: Checking for closed peer connection before send
X-Git-Tag: collectd-5.5.1~48^2~6
X-Git-Url: https://git.verplant.org/?a=commitdiff_plain;h=42a62db99c96d77fd6dc676b76705d8d90156c23;p=collectd.git

Checking for closed peer connection before send
---

diff --git a/src/common.c b/src/common.c
index c2849420..7adbe2ea 100644
--- a/src/common.c
+++ b/src/common.c
@@ -44,6 +44,8 @@
 #include <sys/socket.h>
 #include <netdb.h>
 
+#include <poll.h>
+
 #if HAVE_NETINET_IN_H
 # include <netinet/in.h>
 #endif
@@ -265,9 +267,23 @@ ssize_t swrite (int fd, const void *buf, size_t count)
 	const char *ptr;
 	size_t      nleft;
 	ssize_t     status;
+	struct      pollfd pfd;
 
 	ptr   = (const char *) buf;
 	nleft = count;
+	
+	/* checking for closed peer connection */
+	pfd.fd = fd;
+	pfd.events = POLLIN | POLLHUP | POLLRDNORM;
+	pfd.revents = 0;
+	if (poll(&pfd, 1, 0) > 0) {
+		char buffer[32];
+		if (recv(fd, buffer, sizeof(buffer), MSG_PEEK | MSG_DONTWAIT) == 0) {
+			// if recv returns zero (even though poll() said there is data to be read),
+			// that means the connection has been closed
+			return -1;
+		}
+	}
 
 	while (nleft > 0)
 	{