From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934148AbZLFSZu (ORCPT ); Sun, 6 Dec 2009 13:25:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933978AbZLFSZs (ORCPT ); Sun, 6 Dec 2009 13:25:48 -0500 Received: from mx1.redhat.com ([209.132.183.28]:64676 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933596AbZLFSZs (ORCPT ); Sun, 6 Dec 2009 13:25:48 -0500 Date: Sun, 6 Dec 2009 13:25:30 -0500 From: Ulrich Drepper Message-Id: <200912061825.nB6IPUa1023306@hs20-bc2-1.build.redhat.com> To: a.p.zijlstra@chello.nl, fweisbec@gmail.com, jaswinderrajput@gmail.com, linux-kernel@vger.kernel.org, mingo@elte.hu, paulus@samba.org Subject: Minor optimization in parse_subsystem_tracepoint_event Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Uses of strcat are almost always signs that someone is too lazy to think about the code a bit more carefully. One always has to know about the lengths of the strings involved to avoid buffer overflows. This is one case where the size of the object code for me is reduced by 38 bytes. The code should also be faster, especially if flags is non-NULL. Signed-off-by: Ulrich Drepper diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c index 9e5dbd6..4c0bd3c 100644 --- a/tools/perf/util/parse-events.c +++ b/tools/perf/util/parse-events.c @@ -467,7 +467,6 @@ parse_subsystem_tracepoint_event(char *sys_name, char *flags) while ((evt_ent = readdir(evt_dir))) { char event_opt[MAX_EVOPT_LEN + 1]; int len; - unsigned int rem = MAX_EVOPT_LEN; if (!strcmp(evt_ent->d_name, ".") || !strcmp(evt_ent->d_name, "..") @@ -475,20 +474,12 @@ parse_subsystem_tracepoint_event(char *sys_name, char *flags) || !strcmp(evt_ent->d_name, "filter")) continue; - len = snprintf(event_opt, MAX_EVOPT_LEN, "%s:%s", sys_name, - evt_ent->d_name); + len = snprintf(event_opt, MAX_EVOPT_LEN, "%s:%s%s%s", sys_name, + evt_ent->d_name, flags ? ":" : "", + flags ?: ""); if (len < 0) return EVT_FAILED; - rem -= len; - if (flags) { - if (rem < strlen(flags) + 1) - return EVT_FAILED; - - strcat(event_opt, ":"); - strcat(event_opt, flags); - } - if (parse_events(NULL, event_opt, 0)) return EVT_FAILED; }