NetBSD Problem Report #50863
From www@NetBSD.org Sat Feb 27 17:24:08 2016
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for <gnats-bugs@gnats.NetBSD.org>; Sat, 27 Feb 2016 17:24:08 +0000 (UTC)
Message-Id: <20160227172407.468447ACAF@mollari.NetBSD.org>
Date: Sat, 27 Feb 2016 17:24:07 +0000 (UTC)
From: a6funxh77z@snkmail.com
Reply-To: a6funxh77z@snkmail.com
To: gnats-bugs@NetBSD.org
Subject: libedit el_end() messes up term settings if piped
X-Send-Pr-Version: www-1.0
>Number: 50863
>Category: lib
>Synopsis: libedit el_end() messes up term settings if piped
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: lib-bug-people
>State: closed
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Sat Feb 27 17:25:00 +0000 2016
>Closed-Date: Mon Feb 29 14:59:40 +0000 2016
>Last-Modified: Mon Feb 29 14:59:40 +0000 2016
>Originator: John Hein
>Release: head
>Organization:
none
>Environment:
Noticed with freebsd ports version of libedit (basically 201503 netbsd version). Reproduced with libedit code from netbsd head on freebsd.
FreeBSD foo.example.com 9.3-STABLE-20150728 FreeBSD 9.3-STABLE-20150728 #8: Fri Jul 31 09:01:31 MDT 2015 foo@example.com:/usr/obj/usr/src/sys/FOO i386
Sorry I don't have a netbsd box to use at the moment. But it's easy to confirm if you do. And code inspection of head netbsd code seems to show the problem still exists.
>Description:
==================
% cat foo.c
#include <stdio.h>
#include <histedit.h>
static EditLine *el_e = 0;
int
main(int argc, char **argv)
{
printf("start\n");
el_e = el_init("foo", stdin, stdout, stderr);
if (el_e)
el_end(el_e);
else
printf("el_init failed\n");
printf("end\n");
printf("end\n");
return 0;
}
====================
cc foo.c -ledit -o foo && ./foo | cat
The output after el_end() has stair stepped lines (no CR), 'stty -a' shows the baud rate at 50, and on freebsd at least, that messes up things like vi and such.
Looking at the libedit code, it looks like there's a case where code in el_end() tries to restore the original tty settings. But if the output is not a tty, the original tty settings were never saved. So it restores invalid termios settings.
The problem is that tty_setup() checks if the output file descriptor is a tty and does a short circuit exit before the termios settings can be saved. Then el_end(), unaware that the t_or struct is not correctly populated, happily restores the t_or settings that are bogus.
>How-To-Repeat:
See description.
>Fix:
Record original termios settings in tty_setup() even if not isatty(). Or don't try to restore termios settings in tty_end() if tty_setup() never saved them (set a flag or use a pointer for t_or that's null unless the struct is valid or something like that).
>Release-Note:
>Audit-Trail:
From: "Christos Zoulas" <christos@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc:
Subject: PR/50863 CVS commit: src/lib/libedit
Date: Sat, 27 Feb 2016 13:13:21 -0500
Module Name: src
Committed By: christos
Date: Sat Feb 27 18:13:21 UTC 2016
Modified Files:
src/lib/libedit: tty.c tty.h
Log Message:
PR/50863: John Hein: libedit el_end() messes up term settings if piped
Keep track if we initialized the tty, and only reset it if we did.
To generate a diff of this commit:
cvs rdiff -u -r1.57 -r1.58 src/lib/libedit/tty.c
cvs rdiff -u -r1.18 -r1.19 src/lib/libedit/tty.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
State-Changed-From-To: open->closed
State-Changed-By: dholland@NetBSD.org
State-Changed-When: Mon, 29 Feb 2016 14:59:40 +0000
State-Changed-Why:
Christos fixed it, thanks!
>Unformatted:
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