linux-kernel - Re: OT: calling kernel syscall manually

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Date:	Wed, 13 Sep 2006 07:55:30 +0100
From:	David Woodhouse <dwmw2@...radead.org>
To:	Albert Cahalan <acahalan@...il.com>
Cc:	guest01@...il.com, linux-kernel@...r.kernel.org
Subject: Re: OT: calling kernel syscall manually

On Wed, 2006-09-13 at 01:35 -0400, Albert Cahalan wrote:
> > The third one has always been broken on i386 for PIC code
> 
> No, I was just using it today in PIC i386 code.
> The %ebx register gets pushed, the needed value
> gets moved into %ebx, the int 0x80 is done, and
> the %ebx register gets popped. Only a few odd
> calls like clone() need something different.

That's a very recent change -- it was broken for years before that.

> > and was pointless anyway, since glibc provides this
> > functionality. The kernel method has been removed from
> > userspace visibility all architectures, and we plan to
> > remove it entirely in 2.6.19 since it's not at all useful.
> 
> It's damn useful. Hint: Linux does not require glibc.

Are you being deliberately obtuse or is it just a natural talent?

Other C libraries also provide syscall() -- at least dietlibc and uClibc
do.

Kernel headers do not exist to provide a library of random crap for
userspace to use.
 
-- 
dwmw2

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