Fix #253 - Allow caller to read a partial object

by returning all that was read. Related to #257
which fixed a different path in apdu.c


git-svn-id: https://www.opensc-project.org/svnp/opensc/trunk@4804 c6295689-39f2-0310-b995-f0e70906c6a9

src/libopensc/apdu.c

@@ -490,7 +490,8 @@ static int do_single_transmit(sc_card_t *card, sc_apdu_t *apdu)
 					SC_FUNC_RETURN(ctx, SC_LOG_DEBUG_VERBOSE, r);
 
 				if (buflen < le)
-					return SC_ERROR_WRONG_LENGTH;
+				/* copy as much as will fit in requested buffer */
+					le = buflen;
 
 				memcpy(buf, tbuf, le);
 				buf    += le;