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From: John Baldwin <jhb@freebsd.org>
To: freebsd-current@freebsd.org
Subject: Re: [PATCH] Variable-size ioctl data handling
Date: Tue, 22 Jan 2013 13:54:45 -0500
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Cc: Yuri <yuri@rawbw.com>
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On Monday, January 21, 2013 3:26:21 pm Yuri wrote:
> Hi,
> 
> Could anybody please review and check in the patch 
> patch-ioctl-var-size.txt from this PR: 
> http://www.freebsd.org/cgi/query-pr.cgi?pr=175425 ?
> This patch introduces the generic way to pass variable size ioctl 
> argument using the structure like this struct my_struct {int len; ...any 
> fields...}.

I think this layout is a bit of a special case.  I think you should just put 
the userland pointer in length in the structure you pass to the ioctl as mdf@ 
suggested in the thread on hackers@.  If nothing else, the length should be a 
size_t instead of an int.

-- 
John Baldwin