Patch from Secure Endpoints/Asanka Herath for windows support

lib/krb5/get_default_principal.c

@@ -48,6 +48,8 @@ get_env_user(void)
     return user;
 }
 
+#ifndef _WIN32
+
 /*
  * Will only use operating-system dependant operation to get the
  * default principal, for use of functions that in ccache layer to
@@ -93,7 +95,58 @@ _krb5_get_default_principal_local (krb5_context context,
     return ret;
 }
 
-krb5_error_code KRB5_LIB_FUNCTION
+#else  /* _WIN32 */
+
+#define SECURITY_WIN32
+#include <security.h>
+
+krb5_error_code
+_krb5_get_default_principal_local(krb5_context context,
+				  krb5_principal *princ)
+{
+    krb5_error_code ret = 0;
+
+    /* See if we can get the principal first.  We only expect this to
+       work if logged into a domain. */
+    {
+	char username[1024];
+	ULONG sz = sizeof(username);
+
+	if (GetUserNameEx(NameUserPrincipal, username, &sz)) {
+	    return krb5_parse_name_flags(context, username,
+					 KRB5_PRINCIPAL_PARSE_ENTERPRISE,
+					 princ);
+	}
+    }
+
+    /* Just get the Windows username.  This should pretty much always
+       work. */
+    {
+	char username[1024];
+	DWORD dsz = sizeof(username);
+
+	if (GetUserName(username, &dsz)) {
+	    return krb5_make_principal(context, princ, NULL, username, NULL);
+	}
+    }
+
+    /* Failing that, we look at the environment */
+    {
+	const char * username = get_env_user();
+
+	if (username == NULL) {
+	    krb5_set_error_string(context,
+				  "unable to figure out current principal");
+	    return ENOTTY;	/* Really? */
+	}
+
+	return krb5_make_principal(context, princ, NULL, username, NULL);
+    }
+}
+
+#endif
+
+KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 krb5_get_default_principal (krb5_context context,
 			    krb5_principal *princ)
 {