bin/135417: man -k overrides $PATH for $PAGER

[der Mouse]

>Number:         135417
>Category:       bin
>Synopsis:       man -k overrides $PATH for $PAGER
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Jun 09 15:30:01 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     der Mouse
>Release:        FreeBSD 6.3-RELEASE i386, probably later too
>Organization:
Dis-
>Environment:
System: FreeBSD FreeBSD.Rodents.Montreal.QC.CA 6.3-RELEASE FreeBSD 6.3-RELEASE #0: Wed Jan 16 04:45:45 UTC 2008 root at dessler.cse.buffalo.edu:/usr/obj/usr/src/sys/SMP i386
Code inspection indicates presence in 7.2 (apropos,v 1.16) too.
>Description:
	I have a private version of less, which among other things
	supports an option in $LESS that /usr/bin/less does not.  This
	less is in a directory which occurs before /usr/bin in my
	$PATH, and my $PAGER is "less -s".  In most respects this works
	fine.  But when I run man -k, I get an error from the stock
	less provoked by its failure to understand this private option.
	(Normal use of man does not have this problem; it obeys $PAGER
	just fine.)

	This turns out to be because man -k execs apropos, which is a
	shell script that, as one of its first actions, prepends
	/bin:/usr/bin: to $PATH.

	While I noticed this in 6.3, inspecting
	http://ftp7.freebsd.org/sites/ftp.freebsd.org/pub/FreeBSD/development/FreeBSD-CVS/src/gnu/usr.bin/man/apropos/apropos.sh,v
	leads me to think 7.2 uses the same apropos script and thus has
	the same bug.
>How-To-Repeat:
	Create a private "less" executable which is visibly different
	from /usr/bin/less in some way.  Try using it with man -k.

	Here's a specific recipe, assuming "foo" does not exist:

	(sh syntax)
	$ mkdir foo
	$ cd foo
	$ cp /bin/echo less
	$ export PATH=`pwd`:$PATH PAGER="less -s"
	$ man man
	-s
	$ man -k man

	Note that "man man" runs the less in `pwd`, but "man -k man"
	runs the stock less.
>Fix:
	I'm not sure.  Perhaps save $PATH before modifying it and
	restore it when running $PAGER?  This seems to work for me, but
	may not be Right.

--- apropos	2008-01-15 19:31:25.000000000 -0500
+++ apropos+	2009-06-09 10:57:43.000000000 -0400
@@ -18,6 +18,7 @@
 # $FreeBSD: src/gnu/usr.bin/man/apropos/apropos.sh,v 1.16 2002/10/21 07:44:42 ru Exp $
 
 
+prepath="$PATH"
 PATH=/bin:/usr/bin:$PATH
 db=whatis	# name of whatis data base
 grepopt=''
@@ -106,6 +107,6 @@
 		printf -- "$line2"
 		exit $exit_nomatch
 	else
-		( printf -- "$line2"; echo "$line"; cat ) | $PAGER
+		( printf -- "$line2"; echo "$line"; cat ) | env PATH="$prepath" $PAGER
 	fi
 )

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