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 id 1cENJX-000H4f-0R; Tue, 06 Dec 2016 23:30:15 +0200
Subject: Re: /compat/linux/dev and an odd program
To: Tijl Coosemans <tijl@FreeBSD.org>
References: <1668707b-3f94-ccc4-068c-04869620b4f4@FreeBSD.org>
 <20161206195520.367929e9@kalimero.tijl.coosemans.org>
Cc: freebsd-emulation@FreeBSD.org
From: Andriy Gapon <avg@FreeBSD.org>
Message-ID: <5286e838-f730-c5ff-9d25-119d1ededd23@FreeBSD.org>
Date: Tue, 6 Dec 2016 23:29:16 +0200
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On 06/12/2016 20:55, Tijl Coosemans wrote:
> On Tue, 6 Dec 2016 18:49:06 +0200 Andriy Gapon <avg@FreeBSD.org> wrote:
>> I have an old binary-only Linux program that, for whatever reason, opens
>> /dev/null with O_CREAT flag (O_WRONLY | O_CREAT | O_TRUNC).  That works fine
>> when there is no /compat/linux/dev: the code in kern_alternate_path() sees that
>> the directory does not exist, strips /compat/linux prefix and, so, the real
>> /dev/null is found.  But typically, if linux_base is installed, there is
>> /compat/linux/dev directory, because of /compat/linux/dev/shm/.  The code will
>> see the directory and, thus, it will try to open /compat/linux/dev/null.  But
>> there is no such file, so it will try to create it.  And fail with EPERM for a
>> non-privileged user.
>>
>> I wonder if anyone has thoughts or suggestions on this situation.
>> Either an administrative solution or a code change would be fine for me.
>> Thanks!
> 
> Try creating this symlink:
> 
> ln -s /dev/null /compat/linux/dev/null
> 

That does the job, thank you!


-- 
Andriy Gapon