From: Jens Axboe <jens.axboe@oracle.com>
To: Max Kellermann <max@duempel.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: splice() on two pipes
Date: Thu, 30 Apr 2009 08:21:51 +0200 [thread overview]
Message-ID: <20090430062151.GU4593@kernel.dk> (raw)
In-Reply-To: <20090429103308.GA23684@squirrel.roonstrasse.net>
On Wed, Apr 29 2009, Max Kellermann wrote:
> Hi,
>
> when I read about the splice() system call, I thought it was obvious
> that it could copy data between two pipes. I was surprised that this
> assumption is wrong, it's not possible on 2.6.29, I get EINVAL. Can
> anybody please explain this limitation?
>
> Background: I want to forward data between two subprocesses, which are
> connected to me with a pipe().
>
> I have attached a small test program which prints a table of supported
> splice operations. Here's the output on 2.6.29.1:
>
> in\out pipe sock reg chr
> pipe no yes yes yes
> sock no no no no
> reg yes no no no
> chr no no no no
See sys_tee().
--
Jens Axboe
next prev parent reply other threads:[~2009-04-30 6:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-29 10:33 splice() on two pipes Max Kellermann
2009-04-29 15:23 ` Andi Kleen
2009-04-29 19:42 ` Max Kellermann
2009-04-30 4:56 ` Willy Tarreau
2009-04-30 14:26 ` Mark Hills
2009-04-30 6:21 ` Jens Axboe [this message]
2009-04-30 6:42 ` Max Kellermann
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