mingw: remove obsolete IPv6-related code

To support IPv6, Git provided fall back functions for Windows versions that
did not support IPv6. However, as Git dropped support for Windows XP and
prior, those functions are not needed anymore.

Removed those fallbacks by reverting commit[1] and using the functions
directly (without 'ipv6_' prefix).

[1] fe3b2b7.

Signed-off-by: tanushree27 <tanushreetumane@gmail.com>

Author: tanushree27

compat/mingw.c

@@ -2100,142 +2100,10 @@ int mingw_putenv(const char *namevalue)
 	return result ? 0 : -1;
 }
 
-/*
- * Note, this isn't a complete replacement for getaddrinfo. It assumes
- * that service contains a numerical port, or that 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 = NULL;
-	struct addrinfo *ai;
-	struct sockaddr_in *sin;
-
-	if (node) {
-		h = gethostbyname(node);
-		if (!h)
-			return WSAGetLastError();
-	}
-
-	ai = xmalloc(sizeof(struct addrinfo));
-	*res = ai;
-	ai->ai_flags = 0;
-	ai->ai_family = AF_INET;
-	ai->ai_socktype = hints ? hints->ai_socktype : 0;
-	switch (ai->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);
-	if (hints && (hints->ai_flags & AI_CANONNAME))
-		ai->ai_canonname = h ? xstrdup(h->h_name) : NULL;
-	else
-		ai->ai_canonname = NULL;
-
-	sin = xcalloc(1, ai->ai_addrlen);
-	sin->sin_family = AF_INET;
-	/* Note: getaddrinfo is supposed to allow service to be a string,
-	 * which should be looked up using getservbyname. This is
-	 * currently not implemented */
-	if (service)
-		sin->sin_port = htons(atoi(service));
-	if (h)
-		sin->sin_addr = *(struct in_addr *)h->h_addr;
-	else if (hints && (hints->ai_flags & AI_PASSIVE))
-		sin->sin_addr.s_addr = INADDR_ANY;
-	else
-		sin->sin_addr.s_addr = INADDR_LOOPBACK;
-	ai->ai_addr = (struct sockaddr *)sin;
-	ai->ai_next = NULL;
-	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;
@@ -2244,35 +2112,7 @@ static void ensure_socket_initialization(void)
 		die("unable to initialize winsock subsystem, error %d",
 			WSAGetLastError());
 
-	for (name = libraries; *name; name++) {
-		ipv6_dll = LoadLibraryExA(*name, NULL,
-					  LOAD_LIBRARY_SEARCH_SYSTEM32);
-		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);
+	atexit((void(*)(void)) WSACleanup);
 	initialized = 1;
 }
 
@@ -2290,24 +2130,12 @@ struct hostent *mingw_gethostbyname(const char *host)
 	return gethostbyname(host);
 }
 
-void mingw_freeaddrinfo(struct addrinfo *res)
-{
-	ipv6_freeaddrinfo(res);
-}
-
+#undef getaddrinfo
 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);
+	return getaddrinfo(node, service, hints, res);
 }
 
 int mingw_socket(int domain, int type, int protocol)

compat/mingw.h

@@ -297,18 +297,10 @@ int mingw_gethostname(char *host, int namelen);
 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