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Date: Mon, 21 Aug 2006 10:36:46 +1000
From: Paul Mackerras <paulus@samba.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: =?iso-8859-1?q?Bj=F6rn_Steinbrink?= <B.Steinbrink@gmx.de>,
       Russell King <rmk+lkml@arm.linux.org.uk>, Andrew Morton <akpm@osdl.org>,
       rusty@rustcorp.com.au, linux-kernel@vger.kernel.org,
       linux-arch@vger.kernel.org
Subject: Re: [PATCH] introduce kernel_execve function to replace __KERNEL_SYSCALLS__
In-Reply-To: <200608201913.39989.arnd@arndb.de>
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	<200608201501.29296.arnd@arndb.de>
	<20060820134745.GA11843@atjola.homenet>
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Arnd Bergmann writes:

> Iit turned out most of the architectures that already implement
> their own execve() call instead of using the _syscall3 function
> for it end up passing the return value of sys_execve down, 
> instead of setting errno.

I really don't like having an "errno" variable in the kernel.  What if
two processes are doing an execve concurrently?

Anyway, your patch returns the (positive) errno value here:

> +	WARN_ON(segment_eq(fs, USER_DS));
> +	ret = execve(filename, (char **)argv, (char **)envp);
> +	if (ret)
> +		ret = errno;
> +
> +	return ret;

but here we are testing for a negative value to mean error:

> -	if (execve("/sbin/shutdown", argv, envp) < 0) {
> +	if (kernel_execve("/sbin/shutdown", argv, envp) < 0) {

Paul.