From 4285f2560793dcb388c051cf72854bf8f3e2027d Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris+github@qwirx.com>
Date: Fri, 4 Aug 2017 20:46:42 +0100
Subject: [PATCH] Improve error message on hostname lookup failure

Throw exceptions with a message, including the OS error, which means retrieving
it properly from the winsock library on Windows.
---
 lib/common/Logging.h  |  6 ++++++
 lib/server/Socket.cpp | 26 ++++++++++----------------
 2 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/lib/common/Logging.h b/lib/common/Logging.h
index 7f80d84c0..bcc57d3d1 100644
--- a/lib/common/Logging.h
+++ b/lib/common/Logging.h
@@ -112,12 +112,16 @@
 	#define THROW_WIN_ERROR_NUMBER(message, error_number, exception, subtype) \
 		THROW_EXCEPTION_MESSAGE(exception, subtype, \
 			BOX_WIN_ERRNO_MESSAGE(error_number, message))
+	#define THROW_WIN_ERROR(message, exception, subtype) \
+		THROW_WIN_ERROR_NUMBER(message, GetLastError(), exception, subtype)
 	#define THROW_WIN_FILE_ERRNO(message, filename, error_number, exception, subtype) \
 		THROW_WIN_ERROR_NUMBER(BOX_FILE_MESSAGE(filename, message), \
 			error_number, exception, subtype)
 	#define THROW_WIN_FILE_ERROR(message, filename, exception, subtype) \
 		THROW_WIN_FILE_ERRNO(message, filename, GetLastError(), \
 			exception, subtype)
+	#define THROW_SOCKET_ERROR(message, exception, subtype) \
+		THROW_WIN_ERROR_NUMBER(message, WSAGetLastError(), exception, subtype)
 	#define EMU_ERRNO winerrno
 	#define THROW_EMU_ERROR(message, exception, subtype) \
 		THROW_EXCEPTION_MESSAGE(exception, subtype, \
@@ -127,6 +131,8 @@
 		BOX_SYS_ERRNO_MESSAGE(error_number, stuff)
 	#define BOX_LOG_NATIVE_ERROR(stuff)   BOX_LOG_SYS_ERROR(stuff)
 	#define BOX_LOG_NATIVE_WARNING(stuff) BOX_LOG_SYS_WARNING(stuff)
+	#define THROW_SOCKET_ERROR(message, exception, subtype) \
+		THROW_SYS_ERROR(message, exception, subtype)
 	#define EMU_ERRNO errno
 	#define THROW_EMU_ERROR(message, exception, subtype) \
 		THROW_EXCEPTION_MESSAGE(exception, subtype, \
diff --git a/lib/server/Socket.cpp b/lib/server/Socket.cpp
index c9c1773db..44752fcb2 100644
--- a/lib/server/Socket.cpp
+++ b/lib/server/Socket.cpp
@@ -52,30 +52,24 @@ void Socket::NameLookupToSockAddr(SocketAllAddr &addr, int &sockDomain,
 		{
 			// Lookup hostname
 			struct hostent *phost = ::gethostbyname(rName.c_str());
-			if(phost != NULL)
+			if(phost != NULL && phost->h_addr_list[0] != 0)
 			{
-				if(phost->h_addr_list[0] != 0)
-				{
-					sockAddrLen = sizeof(addr.sa_inet);
+				sockAddrLen = sizeof(addr.sa_inet);
 #ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
-					addr.sa_inet.sin_len = sizeof(addr.sa_inet);
+				addr.sa_inet.sin_len = sizeof(addr.sa_inet);
 #endif
-					addr.sa_inet.sin_family = PF_INET;
-					addr.sa_inet.sin_port = htons(Port);
-					addr.sa_inet.sin_addr = *((in_addr*)phost->h_addr_list[0]);
-					for(unsigned int l = 0; l < sizeof(addr.sa_inet.sin_zero); ++l)
-					{
-						addr.sa_inet.sin_zero[l] = 0;
-					}
-				}
-				else
+				addr.sa_inet.sin_family = PF_INET;
+				addr.sa_inet.sin_port = htons(Port);
+				addr.sa_inet.sin_addr = *((in_addr*)phost->h_addr_list[0]);
+				for(unsigned int l = 0; l < sizeof(addr.sa_inet.sin_zero); ++l)
 				{
-					THROW_EXCEPTION(ConnectionException, SocketNameLookupError);
+					addr.sa_inet.sin_zero[l] = 0;
 				}
 			}
 			else
 			{
-				THROW_EXCEPTION(ConnectionException, SocketNameLookupError);
+				THROW_SOCKET_ERROR("Failed to resolve hostname: " << rName,
+					ConnectionException, SocketNameLookupError);
 			}
 		}
 		break;