From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from intranet.asianux.com (intranet.asianux.com [58.214.24.6]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 5179B2C029B for ; Thu, 28 Feb 2013 22:16:05 +1100 (EST) Message-ID: <512F3C60.9070409@asianux.com> Date: Thu, 28 Feb 2013 19:15:44 +0800 From: Chen Gang MIME-Version: 1.0 To: Jiri Slaby Subject: Re: [PATCH] drivers/tty/hvc: using strlcpy instead of strncpy References: <512C2F5D.1080207@asianux.com> <512F343E.7010201@suse.cz> <512F3BC5.8020903@asianux.com> In-Reply-To: <512F3BC5.8020903@asianux.com> Content-Type: text/plain; charset=UTF-8 Cc: Greg KH , tklauser@distanz.ch, wfp5p@virginia.edu, linuxppc-dev@lists.ozlabs.org, alan@linux.intel.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 于 2013年02月28日 19:13, Chen Gang 写道: > 于 2013年02月28日 18:41, Jiri Slaby 写道: >> On 02/26/2013 04:43 AM, Chen Gang wrote: >>>> >>>> when strlen pi->location_code is larger than HVCS_CLC_LENGTH + 1, >>>> original implementation can not let hvcsd->p_location_code NUL terminated. >>>> so need fix it (also can simplify the code) >> It should never be larger because the +1 is exactly for NUL. But it is a >> cleanup, so why not... >> > > when strlen(&pi->location_code[0]) == HVCS_CLC_LENGTH + 2 > then clclength will be reset to HVCS_CLC_LENGTH. > > when call strncpy, the clclength + 1 == HVCS_CLS_LENGTH + 1 > but the '\0' of src buf is located at HVCS_CLS_LENGTH + 2. but the '\0' of src buf is located at HVCS_CLS_LENGTH + 3. (not + 2) > so no '\0' copied to dest buf. > > then the dest buf will not be ended by '\0'. > > is it correct ? > > :-) > > gchen. > >>>> Signed-off-by: Chen Gang >>>> --- >>>> drivers/tty/hvc/hvcs.c | 9 ++------- >>>> 1 files changed, 2 insertions(+), 7 deletions(-) >>>> >>>> diff --git a/drivers/tty/hvc/hvcs.c b/drivers/tty/hvc/hvcs.c >>>> index 1956593..81e939e 100644 >>>> --- a/drivers/tty/hvc/hvcs.c >>>> +++ b/drivers/tty/hvc/hvcs.c >>>> @@ -881,17 +881,12 @@ static struct vio_driver hvcs_vio_driver = { >>>> /* Only called from hvcs_get_pi please */ >>>> static void hvcs_set_pi(struct hvcs_partner_info *pi, struct hvcs_struct *hvcsd) >>>> { >>>> - int clclength; >>>> - >>>> hvcsd->p_unit_address = pi->unit_address; >>>> hvcsd->p_partition_ID = pi->partition_ID; >>>> - clclength = strlen(&pi->location_code[0]); >>>> - if (clclength > HVCS_CLC_LENGTH) >>>> - clclength = HVCS_CLC_LENGTH; >>>> >>>> /* copy the null-term char too */ >>>> - strncpy(&hvcsd->p_location_code[0], >>>> - &pi->location_code[0], clclength + 1); >>>> + strlcpy(&hvcsd->p_location_code[0], >>>> + &pi->location_code[0], sizeof(hvcsd->p_location_code)); >>>> } >>>> >>>> /* >>>> > > -- Chen Gang Asianux Corporation