linux-kernel - Re: Large pastes into readline enabled programs causes breakage from v2.6.31 onwards

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Message-ID: <5291E92F.7010609@hurleysoftware.com>
Date:	Sun, 24 Nov 2013 06:55:27 -0500
From:	Peter Hurley <peter@...leysoftware.com>
To:	One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>
CC:	Pavel Machek <pavel@....cz>,
	Maximiliano Curia <maxy@...servers.com.ar>,
	Margarita Manterola <margamanterola@...il.com>,
	Arkadiusz Miskiewicz <a.miskiewicz@...il.com>,
	linux-kernel@...r.kernel.org,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jslaby@...e.cz>, bug-readline@....org,
	"Rafael J. Wysocki" <rjw@...ysocki.net>
Subject: Re: Large pastes into readline enabled programs causes breakage from
 v2.6.31 onwards

On 11/23/2013 07:29 PM, One Thousand Gnomes wrote:
>> 7) Rescan line discipline buffer when changing from non-canonical to canonical
>> mode. The real problem with this approach (besides the inefficiency) is that this
>> solution could break some (admittedly unknown) program that contrived to exchange
>> data in non-canonical mode but read in canonical mode (just not exceeding the
>> line discipline buffer limit).
>
> See bugzilla 55981, 55991 btw

Thanks for the bug references, Alan.

The solution proposed in 55991 (to perform an EOF push when switching from
non-canon to canon) would further break paste to readline().

The caller to readline() may not actually perform any read() but may
simply loop, calling readline();  in this case, when readline()
switches back to non-canonical, it will eventually read the inserted '\0'.
That would be bad.

Regards,
Peter Hurley


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