[PATCH 0/2] Add support for IPv6 on MinGW

@@ -903,16 +903,25 @@ char **make_augmented_environ(const char *const *vars)
 	return env;
 }
 
-/* this is the first function to call into WS_32; initialize it */
-#undef gethostbyname
-struct hostent *mingw_gethostbyname(const char *host)
+static void ensure_socket_initialization(void)
 {
 	WSADATA wsa;
+	static int initialized = 0;
+
+	if (initialized)
+		return;
 
 	if (WSAStartup(MAKEWORD(2,2), &wsa))
 		die("unable to initialize winsock subsystem, error %d",
 			WSAGetLastError());
 	atexit((void(*)(void)) WSACleanup);
+	initialized = 1;
+}
+
+#undef gethostbyname
+struct hostent *mingw_gethostbyname(const char *host)
+{
+	ensure_socket_initialization();
 	return gethostbyname(host);
 }
 

@@ -982,7 +982,6 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	NEEDS_CRYPTO_WITH_SSL = YesPlease
 	NO_LIBGEN_H = YesPlease
 	NO_SYMLINK_HEAD = YesPlease
-	NO_IPV6 = YesPlease
 	NO_SETENV = YesPlease
 	NO_UNSETENV = YesPlease
 	NO_STRCASESTR = YesPlease

@@ -903,10 +903,129 @@ char **make_augmented_environ(const char *const *vars)
 	return env;
 }
 
+/*
+ * Note, this isn't a complete replacement for getaddrinfo. It assumes
+ * that service contains a numerical port, or that it it is null. It
+ * does a simple search using gethostbyname, and returns one IPv4 host
+ * if one was found.
+ */
+static int WSAAPI getaddrinfo_stub(const char *node, const char *service,
+				   const struct addrinfo *hints,
+				   struct addrinfo **res)
+{
+	struct hostent *h = gethostbyname(node);
+	struct addrinfo *ai;
+	struct sockaddr_in *sin;
+
+	if (!h)
+		return WSAGetLastError();
+
+	ai = xmalloc(sizeof(struct addrinfo));
+	*res = ai;
+	ai->ai_flags = 0;
+	ai->ai_family = AF_INET;
+	ai->ai_socktype = hints->ai_socktype;
+	switch (hints->ai_socktype) {
+	case SOCK_STREAM:
+		ai->ai_protocol = IPPROTO_TCP;
+		break;
+	case SOCK_DGRAM:
+		ai->ai_protocol = IPPROTO_UDP;
+		break;
+	default:
+		ai->ai_protocol = 0;
+		break;
+	}
+	ai->ai_addrlen = sizeof(struct sockaddr_in);
+	ai->ai_canonname = strdup(h->h_name);
+
+	sin = xmalloc(ai->ai_addrlen);
+	memset(sin, 0, ai->ai_addrlen);
+	sin->sin_family = AF_INET;
+	if (service)
+		sin->sin_port = htons(atoi(service));
+	sin->sin_addr = *(struct in_addr *)h->h_addr;
+	ai->ai_addr = (struct sockaddr *)sin;
+	ai->ai_next = 0;
+	return 0;
+}
+
+static void WSAAPI freeaddrinfo_stub(struct addrinfo *res)
+{
+	free(res->ai_canonname);
+	free(res->ai_addr);
+	free(res);
+}
+
+static int WSAAPI getnameinfo_stub(const struct sockaddr *sa, socklen_t salen,
+				   char *host, DWORD hostlen,
+				   char *serv, DWORD servlen, int flags)
+{
+	const struct sockaddr_in *sin = (const struct sockaddr_in *)sa;
+	if (sa->sa_family != AF_INET)
+		return EAI_FAMILY;
+	if (!host && !serv)
+		return EAI_NONAME;
+
+	if (host && hostlen > 0) {
+		struct hostent *ent = NULL;
+		if (!(flags & NI_NUMERICHOST))
+			ent = gethostbyaddr((const char *)&sin->sin_addr,
+					    sizeof(sin->sin_addr), AF_INET);
+
+		if (ent)
+			snprintf(host, hostlen, "%s", ent->h_name);
+		else if (flags & NI_NAMEREQD)
+			return EAI_NONAME;
+		else
+			snprintf(host, hostlen, "%s", inet_ntoa(sin->sin_addr));
+	}
+
+	if (serv && servlen > 0) {
+		struct servent *ent = NULL;
+		if (!(flags & NI_NUMERICSERV))
+			ent = getservbyport(sin->sin_port,
+					    flags & NI_DGRAM ? "udp" : "tcp");
+
+		if (ent)
+			snprintf(serv, servlen, "%s", ent->s_name);
+		else
+			snprintf(serv, servlen, "%d", ntohs(sin->sin_port));
+	}
+
+	return 0;
+}
+
+static HMODULE ipv6_dll = NULL;
+static void (WSAAPI *ipv6_freeaddrinfo)(struct addrinfo *res);
+static int (WSAAPI *ipv6_getaddrinfo)(const char *node, const char *service,
+				      const struct addrinfo *hints,
+				      struct addrinfo **res);
+static int (WSAAPI *ipv6_getnameinfo)(const struct sockaddr *sa, socklen_t salen,
+				      char *host, DWORD hostlen,
+				      char *serv, DWORD servlen, int flags);
+/*
+ * gai_strerror is an inline function in the ws2tcpip.h header, so we
+ * don't need to try to load that one dynamically.
+ */
+
+static void socket_cleanup(void)
+{
+	WSACleanup();
+	if (ipv6_dll)
+		FreeLibrary(ipv6_dll);
+	ipv6_dll = NULL;
+	ipv6_freeaddrinfo = freeaddrinfo_stub;
+	ipv6_getaddrinfo = getaddrinfo_stub;
+	ipv6_getnameinfo = getnameinfo_stub;
+}
+
 static void ensure_socket_initialization(void)
 {
 	WSADATA wsa;
 	static int initialized = 0;
+	const char *libraries[] = { "ws2_32.dll", "wship6.dll", NULL };
+	const char **name;
 
 	if (initialized)
 		return;

@@ -914,7 +1033,35 @@ static void ensure_socket_initialization(void)
 	if (WSAStartup(MAKEWORD(2,2), &wsa))
 		die("unable to initialize winsock subsystem, error %d",
 			WSAGetLastError());
-	atexit((void(*)(void)) WSACleanup);
+
+	for (name = libraries; *name; name++) {
+		ipv6_dll = LoadLibrary(*name);
+		if (!ipv6_dll)
+			continue;
+
+		ipv6_freeaddrinfo = (void (WSAAPI *)(struct addrinfo *))
+			GetProcAddress(ipv6_dll, "freeaddrinfo");
+		ipv6_getaddrinfo = (int (WSAAPI *)(const char *, const char *,
+						   const struct addrinfo *,
+						   struct addrinfo **))
+			GetProcAddress(ipv6_dll, "getaddrinfo");
+		ipv6_getnameinfo = (int (WSAAPI *)(const struct sockaddr *,
+						   socklen_t, char *, DWORD,
+						   char *, DWORD, int))
+			GetProcAddress(ipv6_dll, "getnameinfo");
+		if (!ipv6_freeaddrinfo || !ipv6_getaddrinfo || !ipv6_getnameinfo) {
+			FreeLibrary(ipv6_dll);
+			ipv6_dll = NULL;
+		} else
+			break;
+	}
+	if (!ipv6_freeaddrinfo || !ipv6_getaddrinfo || !ipv6_getnameinfo) {
+		ipv6_freeaddrinfo = freeaddrinfo_stub;
+		ipv6_getaddrinfo = getaddrinfo_stub;
+		ipv6_getnameinfo = getnameinfo_stub;
+	}
+
+	atexit(socket_cleanup);
 	initialized = 1;
 }
 

@@ -925,6 +1072,26 @@ struct hostent *mingw_gethostbyname(const char *host)
 	return gethostbyname(host);
 }
 
+void mingw_freeaddrinfo(struct addrinfo *res)
+{
+	ipv6_freeaddrinfo(res);
+}
+
+int mingw_getaddrinfo(const char *node, const char *service,
+		      const struct addrinfo *hints, struct addrinfo **res)
+{
+	ensure_socket_initialization();
+	return ipv6_getaddrinfo(node, service, hints, res);
+}
+
+int mingw_getnameinfo(const struct sockaddr *sa, socklen_t salen,
+		      char *host, DWORD hostlen, char *serv, DWORD servlen,
+		      int flags)
+{
+	ensure_socket_initialization();
+	return ipv6_getnameinfo(sa, salen, host, hostlen, serv, servlen, flags);
+}
+
 int mingw_socket(int domain, int type, int protocol)
 {
 	int sockfd;

@@ -1,4 +1,5 @@
 #include <winsock2.h>
+#include <ws2tcpip.h>
 
 /*
  * things that are not available in header files

@@ -178,6 +179,18 @@ char *mingw_getenv(const char *name);
 struct hostent *mingw_gethostbyname(const char *host);
 #define gethostbyname mingw_gethostbyname
 
+void mingw_freeaddrinfo(struct addrinfo *res);
+#define freeaddrinfo mingw_freeaddrinfo
+
+int mingw_getaddrinfo(const char *node, const char *service,
+		      const struct addrinfo *hints, struct addrinfo **res);
+#define getaddrinfo mingw_getaddrinfo
+
+int mingw_getnameinfo(const struct sockaddr *sa, socklen_t salen,
+		      char *host, DWORD hostlen, char *serv, DWORD servlen,
+		      int flags);
+#define getnameinfo mingw_getnameinfo
+
 int mingw_socket(int domain, int type, int protocol);
 #define socket mingw_socket