Wait for the other end to close a unix socket to ensure the message has gone through

src/ckpool.c

@@ -526,6 +526,8 @@ bool _send_proc(proc_instance_t *pi, const char *msg, const char *file, const ch
 	else
 		ret = true;
 	shutdown(sockd, SHUT_WR);
+	if (!wait_close(sockd, 5))
+		LOGWARNING("send_proc did not close from %s %s:%d", file, func, line);
 out:
 	if (unlikely(!ret)) {
 		LOGERR("Failure in send_proc from %s %s:%d", file, func, line);

src/libckpool.c

@@ -910,6 +910,20 @@ out:
 	return sockd;
 }
 
+/* Wait till a socket has been closed at the other end */
+int wait_close(int sockd, int timeout)
+{
+	struct pollfd sfd;
+
+	if (unlikely(sockd < 0))
+		return -1;
+	sfd.fd = sockd;
+	sfd.events = POLLHUP;
+	sfd.revents = 0;
+	timeout *= 1000;
+	return poll(&sfd, 1, timeout);
+}
+
 /* Emulate a select read wait for high fds that select doesn't support */
 int wait_read_select(int sockd, int timeout)
 {

src/libckpool.h

@@ -493,6 +493,7 @@ int _open_unix_server(const char *server_path, const char *file, const char *fun
 #define open_unix_server(server_path) _open_unix_server(server_path, __FILE__, __func__, __LINE__)
 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, int 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);