diff --git a/lib/krb5/get_default_principal.c b/lib/krb5/get_default_principal.c
new file mode 100644
index 000000000..18c687ce4
--- /dev/null
+++ b/lib/krb5/get_default_principal.c
@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 1997 Kungliga Tekniska Högskolan
+ * (Royal Institute of Technology, Stockholm, Sweden). 
+ * All rights reserved. 
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions 
+ * are met: 
+ *
+ * 1. Redistributions of source code must retain the above copyright 
+ *    notice, this list of conditions and the following disclaimer. 
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright 
+ *    notice, this list of conditions and the following disclaimer in the 
+ *    documentation and/or other materials provided with the distribution. 
+ *
+ * 3. All advertising materials mentioning features or use of this software 
+ *    must display the following acknowledgement: 
+ *      This product includes software developed by Kungliga Tekniska 
+ *      Högskolan and its contributors. 
+ *
+ * 4. Neither the name of the Institute nor the names of its contributors 
+ *    may be used to endorse or promote products derived from this software 
+ *    without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
+ * SUCH DAMAGE. 
+ */
+
+#include "krb5_locl.h"
+
+RCSID("$Id$");
+
+krb5_error_code
+krb5_get_default_principal (krb5_context context,
+			    krb5_principal *princ)
+{
+    krb5_error_code ret;
+    char *p;
+
+    p = getenv ("USER");
+    if (p) {
+	ret = krb5_parse_name (context, p, princ);
+	if (ret)
+	    return ret;
+    } else {
+	struct passwd *pw;
+	char *realm;
+
+	pw = getpwuid (getuid ());
+	if (pw == NULL)
+	    return ENOTTY;
+	ret = krb5_get_default_realm (context, &realm);
+	if (ret)
+	    return ret;
+	ret = krb5_build_principal (context,
+				    princ,
+				    strlen(realm),
+				    realm,
+				    pw->pw_name,
+				    NULL);
+	free (realm);
+	if (ret)
+	    return ret;
+    }
+    return 0;
+}