From mboxrd@z Thu Jan  1 00:00:00 1970
From: Julien Grall <julien.grall@linaro.org>
Subject: Re: [PATCH v3 04/24] xen: guestcopy: Provide an helper
 to safely copy string from guest
Date: Tue, 20 Jan 2015 12:45:08 +0000
Message-ID: <54BE4DD4.8050602@linaro.org>
References: <1421159133-31526-1-git-send-email-julien.grall@linaro.org>
	<1421159133-31526-5-git-send-email-julien.grall@linaro.org>
	<54BD44280200007800056A49@mail.emea.novell.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
Received: from mail6.bemta5.messagelabs.com ([195.245.231.135])
	by lists.xen.org with esmtp (Exim 4.72)
	(envelope-from <julien.grall@linaro.org>) id 1YDYBe-0000YQ-JJ
	for xen-devel@lists.xenproject.org; Tue, 20 Jan 2015 12:45:38 +0000
Received: by mail-wi0-f182.google.com with SMTP id n3so21411128wiv.3
	for <xen-devel@lists.xenproject.org>;
	Tue, 20 Jan 2015 04:45:37 -0800 (PST)
In-Reply-To: <54BD44280200007800056A49@mail.emea.novell.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Jan Beulich <JBeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>, ian.campbell@citrix.com, tim@xen.org, Ian Jackson <ian.jackson@eu.citrix.com>, stefano.stabellini@citrix.com, xen-devel@lists.xenproject.org, Daniel De Graaf <dgdegra@tycho.nsa.gov>
List-Id: xen-devel@lists.xenproject.org

Hi Jan,

On 19/01/15 16:51, Jan Beulich wrote:
>>>> On 13.01.15 at 15:25, <julien.grall@linaro.org> wrote:
>> --- /dev/null
>> +++ b/xen/common/guestcopy.c
>> @@ -0,0 +1,30 @@
>> +#include <xen/config.h>
>> +#include <xen/lib.h>
>> +#include <xen/guest_access.h>
>> +#include <xen/err.h>
>> +
>> +/* The function copies a string from the guest and adds a NUL to
>> + * make sure the string is correctly terminated.
>> + */
> 
> Coding style.

Ok.

> 
>> +void *safe_copy_string_from_guest(XEN_GUEST_HANDLE(char) u_buf,
>> +                                  size_t size, size_t max_size)
> 
> Is the "safe_" prefix really meaningful? I.e. is this function more
> safe than e.g. copy_from_guest()?

It's safe in the sense, the function adds a NUL to make sure the strings
is correctly terminated.

On the first v1, you said that name "copy_string_from_guest" doesn't
match the behavior of the generic helper [1]. So which name do you
suggest for this function?

> 
>> +{
>> +    char *tmp;
>> +
>> +    if ( size > max_size )
>> +        return ERR_PTR(-ENOENT);
> 
> -ENOBUFS?

I will use it.

Regards,

[1] http://lists.xen.org/archives/html/xen-devel/2014-06/msg02361.html

-- 
Julien Grall