From b622a6ec8d9329b7736491dc7641c7f55933df07 Mon Sep 17 00:00:00 2001
From: Con Kolivas <kernel@kolivas.org>
Date: Mon, 14 Dec 2015 23:22:16 +1100
Subject: [PATCH] Check for errors in wait_read_select, closing the socket if
 they occur, and add a variant for non-unix sockets that checks for hangups as
 well

---
 src/ckpool.c    |  2 +-
 src/generator.c |  4 ++--
 src/libckpool.c | 38 +++++++++++++++++++++++++++-----------
 src/libckpool.h |  5 ++++-
 4 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/src/ckpool.c b/src/ckpool.c
index 70269b46..aff75444 100644
--- a/src/ckpool.c
+++ b/src/ckpool.c
@@ -527,7 +527,7 @@ rewait:
 		ret = 0;
 		goto out;
 	}
-	ret = wait_read_select(cs->fd, eom ? 0 : *timeout);
+	ret = wait_recv_select(cs->fd, eom ? 0 : *timeout);
 	if (ret < 1) {
 		if (!ret) {
 			if (eom)
diff --git a/src/generator.c b/src/generator.c
index 2853baf7..da28e55f 100644
--- a/src/generator.c
+++ b/src/generator.c
@@ -290,7 +290,7 @@ retry:
 	ckmsgq_add(gdata->srvchk, si);
 
 	do {
-		selret = wait_read_select(us->sockd, 5);
+		selret = wait_recv_select(us->sockd, 5);
 		if (!selret && !ping_main(ckp)) {
 			LOGEMERG("Generator failed to ping main process, exiting");
 			ret = 1;
@@ -1632,7 +1632,7 @@ retry:
 	ckmsgq_add(gdata->srvchk, proxi->si);
 
 	do {
-		selret = wait_read_select(us->sockd, 5);
+		selret = wait_recv_select(us->sockd, 5);
 		if (!selret && !ping_main(ckp)) {
 			LOGEMERG("Generator failed to ping main process, exiting");
 			ret = 1;
diff --git a/src/libckpool.c b/src/libckpool.c
index 8e08253a..3ba15232 100644
--- a/src/libckpool.c
+++ b/src/libckpool.c
@@ -758,17 +758,15 @@ out:
 
 void empty_socket(int fd)
 {
+	char buf[PAGESIZE];
 	int ret;
 
 	if (fd < 1)
 		return;
 
 	do {
-		char buf[PAGESIZE];
-
-		ret = wait_read_select(fd, 0);
+		ret = recv(fd, buf, PAGESIZE - 1, MSG_DONTWAIT);
 		if (ret > 0) {
-			ret = recv(fd, buf, PAGESIZE - 1, 0);
 			buf[ret] = 0;
 			LOGDEBUG("Discarding: %s", buf);
 		}
@@ -907,21 +905,39 @@ int wait_close(int sockd, int timeout)
 	return sfd.revents & (POLLHUP | POLLRDHUP | POLLERR);
 }
 
-/* Emulate a select read wait for high fds that select doesn't support */
-int wait_read_select(int sockd, float timeout)
+/* Emulate a select read wait for high fds that select doesn't support.
+ * wait_read_select is for unix sockets and _wait_recv_select for regular
+ * sockets. */
+int _wait_read_select(int *sockd, float timeout)
 {
 	struct pollfd sfd;
 	int ret = -1;
 
-	if (unlikely(sockd < 0))
+	if (unlikely(*sockd < 0))
 		goto out;
-	sfd.fd = sockd;
+	sfd.fd = *sockd;
 	sfd.events = POLLIN | POLLRDHUP;
-	sfd.revents = 0;
 	timeout *= 1000;
 	ret = poll(&sfd, 1, timeout);
-	if (ret && !(sfd.revents & POLLIN))
-		ret = -1;
+	if (ret > 0 && sfd.revents & (POLLERR))
+		_Close(sockd);
+out:
+	return ret;
+}
+
+int _wait_recv_select(int *sockd, float timeout)
+{
+	struct pollfd sfd;
+	int ret = -1;
+
+	if (unlikely(*sockd < 0))
+		goto out;
+	sfd.fd = *sockd;
+	sfd.events = POLLIN | POLLRDHUP;
+	timeout *= 1000;
+	ret = poll(&sfd, 1, timeout);
+	if (ret > 0 && sfd.revents & (POLLHUP | POLLRDHUP | POLLERR))
+		_Close(sockd);
 out:
 	return ret;
 }
diff --git a/src/libckpool.h b/src/libckpool.h
index 9d8ba341..222ce26f 100644
--- a/src/libckpool.h
+++ b/src/libckpool.h
@@ -496,7 +496,10 @@ int _open_unix_server(const char *server_path, const char *file, const char *fun
 int _open_unix_client(const char *server_path, const char *file, const char *func, const int line);
 #define open_unix_client(server_path) _open_unix_client(server_path, __FILE__, __func__, __LINE__)
 int wait_close(int sockd, int timeout);
-int wait_read_select(int sockd, float timeout);
+int _wait_read_select(int *sockd, float timeout);
+#define wait_read_select(SOCKD, TIMEOUT) _wait_read_select(&(SOCKD), TIMEOUT)
+int _wait_recv_select(int *sockd, float timeout);
+#define wait_recv_select(SOCKD, TIMEOUT) _wait_recv_select(&(SOCKD), TIMEOUT)
 int read_length(int sockd, void *buf, int len);
 char *_recv_unix_msg(int sockd, int timeout1, int timeout2, const char *file, const char *func, const int line);
 #define RECV_UNIX_TIMEOUT1 30