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Date: Mon, 4 Feb 2013 17:45:40 +1100 (EST)
From: Bruce Evans <brde@optusnet.com.au>
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To: Eitan Adler <lists@eitanadler.com>
Subject: Re: kern/175674: sem_open() should use O_EXLOCK with open() instead
 of a separate flock() call
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Cc: freebsd-bugs@FreeBSD.org, Giorgos Keramidas <keramida@FreeBSD.org>,
 Jilles Tjoelker <jilles@stack.nl>
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On Sun, 3 Feb 2013, Eitan Adler wrote:

> On 3 February 2013 16:00, Giorgos Keramidas <keramida@freebsd.org> wrote:
>> The following reply was made to PR kern/175674; it has been noted by GNATS.
>> > The best way to fix this is in kern_openat() in the kernel but this
>> > might cause compatibility issues.
>>
>>  Not sure if there would be serious compatibility problems if open() would
>>  automatically restart instead of returning EINTR.  It definitely seems a rather
>>  intrusive change though.
>
> I can not see major application breakage should open(3) be changed.
>
> That said,  I am confused by jilles' comment:
> http://pubs.opengroup.org/onlinepubs/000095399/functions/open.html
> open(3) is permitted to return EINTR.

Actually, open(3) is _required_ to return EINTR (if a signal occurs).

This hasn't changed since the old (2001) POSIX draft that I quoted in a
more detailed reply.  The wording is "shall fail...[with EINTR] if a
signal was caught during open()".  Only a perverse implementation of
weaselnix would justify not returning EINTR by not catching signals.

Bruce