krb5: add krb5_store_datalen()

Store a data blob to the storage. The data is stored with an int32 as
length plus the data (not padded).  This function only differs from
krb5_store_data() insofar as it takes a void * and a length as parameters.

Patch from Roland C. Dowdeswell <elric@imrryr.org>

lib/krb5/libkrb5-exports.def.in

@@ -660,6 +660,7 @@ EXPORTS
 	krb5_store_creds
 	krb5_store_creds_tag
 	krb5_store_data
+	krb5_store_datalen
 	krb5_store_int16
 	krb5_store_int32
 	krb5_store_int64

lib/krb5/store.c

@@ -785,6 +785,28 @@ krb5_store_data(krb5_storage *sp,
     return 0;
 }
 
+/**
+ * Store a data blob to the storage. The data is stored with an int32 as
+ * length plus the data (not padded).  This function only differs from
+ * krb5_store_data() insofar as it takes a void * and a length as parameters.
+ *
+ * @param sp the storage buffer to write to
+ * @param s the string to store.
+ * @param len length of the string to be stored.
+ *
+ * @return 0 on success, a Kerberos 5 error code on failure.
+ *
+ * @ingroup krb5_storage
+ */
+KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
+krb5_store_datalen(krb5_storage *sp, void *d, size_t len)
+{
+    krb5_data data;
+    data.length = len;
+    data.data = d;
+    return krb5_store_data(sp, data);
+}
+
 /**
  * Parse a data from the storage.
  *

lib/krb5/version-script.map

@@ -653,6 +653,7 @@ HEIMDAL_KRB5_2.0 {
 		krb5_store_creds;
 		krb5_store_creds_tag;
 		krb5_store_data;
+		krb5_store_datalen;
 		krb5_store_int16;
 		krb5_store_int32;
 		krb5_store_int64;