From: Jens Gustedt <jens.gustedt@inria.fr>
To: musl@lists.openwall.com
Subject: Re: time code progress
Date: Wed, 17 Jul 2013 15:39:35 +0200 [thread overview]
Message-ID: <1374068375.20259.255.camel@eris.loria.fr> (raw)
In-Reply-To: <20130717131948.GU15323@port70.net>
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Am Mittwoch, den 17.07.2013, 15:19 +0200 schrieb Szabolcs Nagy:
> note that the problem is not that __VA_ARGS__ is empty
> (it's not, contrary to what i might implied), but that
> if n becomes 0 (== __VA_ARGS__ expands to one argument),
> then there is no more arguments in the __SYSCALL_NARGS_X
> call to substitute for '...', so a simple fix would be
>
> #define __SYSCALL_NARGS(...) __SYSCALL_NARGS_X(__VA_ARGS__,7,6,5,4,3,2,1,0, tralala)
right, you always have the name of the syscall as first argument
> but i'm not sure if this should be fixed (this is internal
> code and i think there are no 0 argument syscalls)
>
> i just wanted to record how i found the close without fd issue
> (which shows that some kind of type checking for syscall
> arguments would help libc hacking.. but that's non-trivial
> to do)
if there are really no 0 argument syscalls
#define __SYSCALL_NARGS(...) __SYSCALL_NARGS_X(__VA_ARGS__,7,6,5,4,3,2,1, tralali, tralala)
would be an implementation of a first consistency test. But wait my
man page of syscall(2) already has an example of a 0 argument one.
Other consistency checks would probably a bit more difficult to
implement. I could imagine how to check for the number of arguments of
particular syscalls. Type checking would be more difficult, and would
probably need some maintenance.
Jens
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next prev parent reply other threads:[~2013-07-17 13:39 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-16 19:45 Rich Felker
2013-07-17 9:33 ` Rich Felker
2013-07-17 11:39 ` Szabolcs Nagy
2013-07-17 12:09 ` Jens Gustedt
2013-07-17 13:19 ` Szabolcs Nagy
2013-07-17 13:39 ` Jens Gustedt [this message]
2013-07-17 14:36 ` Rich Felker
2013-07-17 13:31 ` Rich Felker
2013-07-17 14:27 ` Szabolcs Nagy
2013-07-20 1:11 ` Szabolcs Nagy
2013-07-20 1:22 ` Rich Felker
2013-07-20 1:29 ` Szabolcs Nagy
2013-07-20 1:35 ` Rich Felker
2013-07-22 21:38 ` Rob Landley
2013-07-22 21:46 ` Rich Felker
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