Cleanups to sk_namelookup(). In particular, it now doesn't segfault

if you explicitly specify IPv6 and then try to look up a hostname
which doesn't have an IPv6 address.

git-svn-id: svn://svn.tartarus.org/sgt/putty@5082 cda61777-01e9-0310-a592-d414129be87e

diff --git a/windows/winnet.c b/windows/winnet.c
index 94b8460..4930698 100644 (file)
--- a/windows/winnet.c
+++ b/windows/winnet.c
@@ -306,6 +306,8 @@ SockAddr sk_namelookup(const char *host, char **canonicalname,
     unsigned long a;
     struct hostent *h = NULL;
     char realhost[8192];
+    int ret_family;
+    int err;
 
     /* Clear the structure and default to IPv4. */
     memset(ret, 0, sizeof(struct SockAddr_tag));
@@ -314,6 +316,7 @@ SockAddr sk_namelookup(const char *host, char **canonicalname,
                   address_family == ADDRTYPE_IPV6 ? AF_INET6 :
 #endif
                   AF_UNSPEC);
+    ret_family = AF_UNSPEC;
     *realhost = '\0';
 
     if ((a = p_inet_addr(host)) == (unsigned long) INADDR_NONE) {
@@ -324,9 +327,8 @@ SockAddr sk_namelookup(const char *host, char **canonicalname,
         * it will fallback to IPv4. */
        typedef int (CALLBACK * FGETADDRINFO) (const char *nodename,
                                               const char *servname,
-                                              const struct addrinfo *
-                                              hints,
-                                              struct addrinfo ** res);
+                                              const struct addrinfo *hints,
+                                              struct addrinfo **res);
        FGETADDRINFO fGetAddrInfo = NULL;
 
        HINSTANCE dllWSHIP6 = LoadLibrary("wship6.dll");
@@ -338,11 +340,11 @@ SockAddr sk_namelookup(const char *host, char **canonicalname,
         * Use fGetAddrInfo when it's available
         */
        if (fGetAddrInfo) {
-               struct addrinfo hints;
-               memset(&hints, 0, sizeof(hints));
-               hints.ai_family = ret->family;
-               if (fGetAddrInfo(host, NULL, &hints, &ret->ai) == 0)
-                       ret->family = ret->ai->ai_family;
+           struct addrinfo hints;
+           memset(&hints, 0, sizeof(hints));
+           hints.ai_family = ret->family;
+           if ((err = fGetAddrInfo(host, NULL, &hints, &ret->ai)) == 0)
+               ret_family = ret->ai->ai_family;
        } else
 #endif
        {
@@ -350,24 +352,23 @@ SockAddr sk_namelookup(const char *host, char **canonicalname,
             * Otherwise use the IPv4-only gethostbyname...
             * (NOTE: we don't use gethostbyname as a fallback!)
             */
-           if (ret->family == 0) {
-               if ( (h = p_gethostbyname(host)) )
-                   ret->family = AF_INET;
-           }
+           if ( (h = p_gethostbyname(host)) )
+               ret_family = AF_INET;
+           else
+               err = p_WSAGetLastError();
        }
 
-       if (ret->family == AF_UNSPEC) {
-           DWORD err = p_WSAGetLastError();
+       if (ret_family == AF_UNSPEC) {
            ret->error = (err == WSAENETDOWN ? "Network is down" :
-                         err ==
-                         WSAHOST_NOT_FOUND ? "Host does not exist" : err
-                         == WSATRY_AGAIN ? "Host not found" :
+                         err == WSAHOST_NOT_FOUND ? "Host does not exist" :
+                         err == WSATRY_AGAIN ? "Host not found" :
 #ifndef NO_IPV6
                          fGetAddrInfo ? "getaddrinfo: unknown error" :
 #endif
                          "gethostbyname: unknown error");
        } else {
            ret->error = NULL;
+           ret->family = ret_family;
 
 #ifndef NO_IPV6
            /* If we got an address info use that... */