From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752018AbaEFNWS (ORCPT ); Tue, 6 May 2014 09:22:18 -0400 Received: from mail-qg0-f48.google.com ([209.85.192.48]:33106 "EHLO mail-qg0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750757AbaEFNWR (ORCPT ); Tue, 6 May 2014 09:22:17 -0400 Date: Tue, 6 May 2014 09:22:14 -0400 From: Tejun Heo To: lizefan@huawei.com Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/9] cgroup: update and fix parsing of "cgroup.subtree_control" Message-ID: <20140506132214.GC27738@htj.dyndns.org> References: <1399377044-29873-1-git-send-email-tj@kernel.org> <1399377044-29873-3-git-send-email-tj@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1399377044-29873-3-git-send-email-tj@kernel.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I was confused that strsep() was equivalent to strtok_r() in skipping over consecutive delimiters. strsep() just splits at the first occurrence of one of the delimiters which makes the parsing very inflexible, which makes allowing multiple whitespace chars as delimters kinda moot. Let's just be consistently strict and require list of tokens separated by spaces. This is what Documentation/cgroups/unified-hierarchy.txt describes too. Also, parsing may access beyond the end of the string if the string ends with spaces or is zero-length. Make sure it skips zero-length tokens. Note that this also ensures that the parser doesn't puke on multiple consecutive spaces. v2: Add zero-length token skipping. Signed-off-by: Tejun Heo --- kernel/cgroup.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 54fd12d..9e6b4ac 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2542,11 +2542,13 @@ static int cgroup_subtree_control_write(struct cgroup_subsys_state *dummy_css, int ssid, ret; /* - * Parse input - white space separated list of subsystem names - * prefixed with either + or -. + * Parse input - space separated list of subsystem names prefixed + * with either + or -. */ p = buffer; - while ((tok = strsep(&p, " \t\n"))) { + while ((tok = strsep(&p, " "))) { + if (tok[0] =='\0') + continue; for_each_subsys(ss, ssid) { if (ss->disabled || strcmp(tok + 1, ss->name)) continue; -- 1.9.0