From: Johannes Sixt <j.sixt@viscovery•net>
To: Finn Arne Gangstad <finnag@pvv•org>
Cc: Michal Rokos <michal.rokos@nextsoft•cz>, GIT <git@vger•kernel.org>
Subject: Re: [PATCH] Add compat/vsnprintf.c for systems that returns -1 on maxsize reached
Date: Tue, 04 Mar 2008 17:19:18 +0100 [thread overview]
Message-ID: <47CD7686.9040501@viscovery.net> (raw)
In-Reply-To: <20080304140930.GA23335@pvv.org>
Finn Arne Gangstad schrieb:
> On Tue, Mar 04, 2008 at 02:59:28PM +0100, Michal Rokos wrote:
>
>> + while ( ret == -1 )
>> + {
>> + maxsize = (maxsize*3)/2;
>> + s = realloc(s, maxsize);
>> + if (! s) return -1;
>> + ret = vsnprintf(s, maxsize, format, ap); /* <--- UNSAFE! */
>> + }
>
> This is not generally safe, you cannot call vsnprintf multiple times
> with the same ap on all architectures. You need va_copy (or __va_copy,
> or VA_COPY, differs a bit between different architectures, especially
> one the ones with a broken vsnprintf I guess..)
True. But...
This replacement of vsnprintf will not be needed on all architectures, but
only on some. And on these we can test in advance whether we can get away
without va_copy (et.al.). A note next to the configuration setting about
this would be in order, I think.
Furthermore, on systems where vsnprintf is broken in this way, va_copy is
likely not available.
-- Hannes
next prev parent reply other threads:[~2008-03-04 16:20 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-04 13:59 [PATCH] Add compat/vsnprintf.c for systems that returns -1 on maxsize reached Michal Rokos
2008-03-04 14:09 ` Johannes Schindelin
2008-03-04 14:09 ` Finn Arne Gangstad
2008-03-04 16:19 ` Johannes Sixt [this message]
2008-03-04 14:12 ` Morten Welinder
2008-03-04 16:28 ` Johannes Sixt
2008-03-04 23:51 ` Wayne Davison
2008-03-05 8:37 ` Michal Rokos
2008-03-05 8:44 ` Jeff King
2008-03-05 9:18 ` Johannes Sixt
2008-03-05 13:55 ` Michal Rokos
2008-03-05 14:28 ` Johannes Sixt
2008-03-05 15:00 ` Michal Rokos
2008-03-05 15:22 ` Johannes Sixt
2008-03-05 15:48 ` Michal Rokos
2008-03-05 15:54 ` Wayne Davison
2008-03-05 16:04 ` Johannes Sixt
2008-03-05 22:33 ` Wayne Davison
2008-03-05 21:05 ` Junio C Hamano
2008-03-05 9:22 ` Mike Ralphson
2008-03-05 10:35 ` Robert Haines
2008-03-05 13:58 ` Michal Rokos
2008-03-10 8:59 ` Michal Rokos
2008-03-10 9:28 ` Johannes Sixt
2008-03-10 9:47 ` Michal Rokos
2008-03-10 10:05 ` Johannes Sixt
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