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From: Chet Ramey <chet.ramey@case.edu>
To: sukadev@linux.vnet.ibm.com
Cc: linux-fsdevel@vger.kernel.org, bug-bash@gnu.org, chet@po.cwru.edu
Subject: Re: bash: Correct usage of F_SETFD
Date: Mon, 22 Nov 2010 17:16:40 -0500	[thread overview]
Message-ID: <101122221640.AA32947.SM@caleb.INS.CWRU.Edu> (raw)
In-Reply-To: Message from sukadev@linux.vnet.ibm.com of Mon, 22 Nov 2010 12:16:20 -0800 (id <20101122201620.GA16687@us.ibm.com>)

> include/filecntl.h in bash-4.1 has following:
> 
> #define SET_CLOSE_ON_EXEC(fd)  (fcntl ((fd), F_SETFD, FD_CLOEXEC))
> 
> Is that really the correct/intended usage of F_SETFD ?

     F_SETFD            Set the close-on-exec flag associated with fildes to
                        the low order bit of arg (0 or 1 as above).

> If kernel ever adds a new flag to the fd, this would end up clearing the
> other new flag right ?
> 
> Shouldn't bash use F_GETFD to get the current flags and set/clear just
> the FD_CLOEXEC bit ?

I suppose it would matter if there are systems that have more than one
flag value.

Chet

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
		 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/

  reply	other threads:[~2010-11-22 22:16 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-22 20:16 bash: Correct usage of F_SETFD Sukadev Bhattiprolu
2010-11-22 22:16 ` Chet Ramey [this message]
2010-11-22 22:27   ` Eric Blake
2010-11-23  0:04     ` Sukadev Bhattiprolu
2010-11-23 14:42       ` Matthew Wilcox
2010-11-23 14:51         ` Eric Blake
2010-11-23 17:51           ` Sukadev Bhattiprolu
2010-11-24  1:17     ` Jamie Lokier

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