linux-kernel - Re: 3.5.rc2 tty buffering bug ?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAM_iQpV4WOSafe8X9pjV++CUJyb30VDOVVKOiusA9OxGyj6CTw@mail.gmail.com>
Date:	Fri, 15 Jun 2012 18:32:54 +0800
From:	Cong Wang <xiyou.wangcong@...il.com>
To:	Dave Jones <davej@...hat.com>,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	Alan Cox <alan@...rguk.ukuu.org.uk>
Subject: Re: 3.5.rc2 tty buffering bug ?

On Fri, Jun 15, 2012 at 12:13 AM, Dave Jones <davej@...hat.com> wrote:
> but when redirected to a file, sometimes it prints what we expect, but other times
> (if the child exits first) it seems to print..
>
> begin
> child
> end
> begin
> parent
> end
>
>
> How does 'begin' get printed a second time ?
>

setbuf(3) said:

"
Normally  all files are block buffered. [...]
If a stream refers to a terminal (as stdout normally does) it is line buffered.
The standard error stream stderr is always unbuffered by default.
"
So when you redirect stdout to a file, "begin\n" is buffered too, both
in child and in parent.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/