linux-kernel - Re: [PATCH] perf cpumap: Use scnprintf instead of snprintf

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Message-ID: <8bb4696a-3470-6613-50ce-a002fbce6b23@wanadoo.fr>
Date:   Mon, 23 Mar 2020 16:20:06 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     linux-kernel@...r.kernel.org
Cc:     kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] perf cpumap: Use scnprintf instead of snprintf

Le 23/03/2020 à 16:11, David Laight a écrit :
> From: Christophe JAILLET
>> Sent: 22 March 2020 17:25
>> 'scnprintf' returns the number of characters written in the output buffer
>> excluding the trailing '\0', instead of the number of characters which
>> would be generated for the given input.
>>
>> Both function return a number of characters, excluding the trailing '\0'.
>> So comparaison to check if it overflows, should be done against max_size-1.
>> Comparaison against max_size can never match.
> NACK.
> Since snprintf() returns the number of characters it would have
> written to an infinite buffer the comparison can 'match'.
>
> However it should test for (ret >= PATH_MAX).

Agreed. I'll send a V2.

CJ

> 	David
>
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