Split fallback realm code into krb5_get_fallback_host_realm

git-svn-id: svn://anonsvn.mit.edu/krb5/users/amb/referrals@18432 dc483132-0cff-0310-8789-dd5450dbe970

diff --git a/src/lib/krb5/os/hst_realm.c b/src/lib/krb5/os/hst_realm.c
index 7b1c94f6026f65bd9a26b6f652d21afe41b4b6b4..9a6049386a6e5499f9d7547304146f984433d899 100644 (file)
--- a/src/lib/krb5/os/hst_realm.c
+++ b/src/lib/krb5/os/hst_realm.c
@@ -355,3 +355,74 @@ krb5int_translate_gai_error (int num)
     abort ();
     return -1;
 }
+
+
+/*
+ * Ganked from krb5_get_host_realm; handles case where referrals have
+ * failed and it's time to go look at TXT records or make a DNS-based
+ * assumption.
+ */
+
+krb5_error_code KRB5_CALLCONV
+krb5_get_fallback_host_realm(krb5_context context, const char *host, char ***realmsp)
+{
+    char **retrealms;
+    char *default_realm, *realm, *cp, *temp_realm;
+    krb5_error_code retval;
+    char local_host[MAXDNAME+1];
+
+    printf("get_fallback_host_realm(host:%s) called\n",host);
+
+#ifdef KRB5_DNS_LOOKUP
+    if (realm == (char *)NULL) {
+        int use_dns = _krb5_use_dns_realm(context);
+        if ( use_dns ) {
+            /*
+             * Since this didn't appear in our config file, try looking
+             * it up via DNS.  Look for a TXT records of the form:
+             *
+             * _kerberos.<hostname>
+             *
+             */
+            cp = local_host;
+            do {
+                retval = krb5_try_realm_txt_rr("_kerberos", cp, &realm);
+                cp = strchr(cp,'.');
+                if (cp) 
+                    cp++;
+            } while (retval && cp && cp[0]);
+        }
+    }
+#endif /* KRB5_DNS_LOOKUP */
+    if (realm == (char *)NULL) {
+        if (default_realm != (char *)NULL) {
+            /* We are defaulting to the realm of the host */
+            if (!(cp = (char *)malloc(strlen(default_realm)+1)))
+                return ENOMEM;
+            strcpy(cp, default_realm);
+            realm = cp;
+
+            /* Assume the realm name is upper case */
+            for (cp = realm; *cp; cp++)
+                if (islower((int) (*cp)))
+                    *cp = toupper((int) *cp);
+        } else {    
+            /* We are defaulting to the local realm */
+            retval = krb5_get_default_realm(context, &realm);
+            if (retval) {
+                return retval;
+            }
+        }
+    }
+    if (!(retrealms = (char **)calloc(2, sizeof(*retrealms)))) {
+       if (realm != (char *)NULL)
+           free(realm);
+       return ENOMEM;
+    }
+
+    retrealms[0] = realm;
+    retrealms[1] = 0;
+    
+    *realmsp = retrealms;
+    return 0;
+}