bin/130298: sh(1) does not handle negation correctly in complex commands

[Jilles Tjoelker]

The following reply was made to PR bin/130298; it has been noted by GNATS.

From: Jilles Tjoelker <jilles at stack.nl>
To: bug-followup at FreeBSD.org, mb at tns.cz, stefanf at freebsd.org
Cc:  
Subject: Re: bin/130298: sh(1) does not handle negation correctly in
	complex commands
Date: Sun, 5 Apr 2009 00:28:14 +0200

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 This is a subtle bug in the parser. It keeps track of whether it should
 recognize keywords such as '!' and 'if' (checkkwd global), but it fails
 to enable this recognition again after && and ||. Hence, the '!' is not
 recognized by pipeline(). Then, command() does enable the recognition
 and picks up the '!'. So,  cmd1 && ! cmd2 | cmd3  puts the negation on
 cmd2 instead of cmd2 | cmd3 and does not work properly. Setting checkkwd
 in pipeline() fixes the problem (patch attached).
 
 After I figured this out I noticed NetBSD had already done it, and in
 the same way.
 http://cvsweb.netbsd.org/bsdweb.cgi/src/bin/sh/parser.c.diff?r1=1.64&r2=1.65&f=h
 
 If the attachment is mangled, try
 http://www.stack.nl/~jilles/unix/sh-parser-and-pipe-not.patch
 
 -- 
 Jilles Tjoelker
 
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 --- src/bin/sh/parser.c.orig	2008-09-04 19:34:53.000000000 +0200
 +++ src/bin/sh/parser.c	2009-04-05 00:02:51.000000000 +0200
 @@ -250,6 +250,7 @@ pipeline(void)
  	int negate;
  
  	negate = 0;
 +	checkkwd = 2;
  	TRACE(("pipeline: entered\n"));
  	while (readtoken() == TNOT)
  		negate = !negate;
 
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