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Date: Mon, 24 Jul 2006 21:13:01 +0400
From: Yar Tikhiy <yar@comp.chem.msu.su>
To: freebsd-rc@FreeBSD.org
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Subject: Order of _nice, _user, and _chdir
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Hi all,

I saw a complaint in a Russian BSD newsgroup that it was impossible
to assign a negative niceness to the $command process via $foo_nice
whenever $foo_user was set to a non-root user.  So I took a look
at the part of rc.subr dealing with the start of $command.  As of
now, the order of processing foo_chdir, foo_nice, and foo_user is
as follows:

	user ( chdir ; nice ( command ) )

E.g.:

	su -m $foo_user -c 'sh -c "cd $foo_chdir ; nice -n $foo_nice $command"'

Therefore the command's process(es) may not be assigned a negative
niceness because nice(1) is run as the unprivileged $foo_user.  In
addition, a failure to chdir() will be ignored.  IMHO a better order
would be:

	nice ( user ( chdir && command ) )

E.g.:

	nice -n $foo_nice su -m $foo_user -c 'sh -c "cd $foo_chdir && $command"'
	nice -n $foo_nice sh -c "cd $foo_chdir && $command" # w/o foo_user

The respective patch is attached.

Any comments?  Thanks.

-- 
Yar

Index: rc.subr
===================================================================
RCS file: /home/ncvs/src/etc/rc.subr,v
retrieving revision 1.59
diff -u -p -r1.59 rc.subr
--- rc.subr	21 Jun 2006 09:42:55 -0000	1.59
+++ rc.subr	24 Jul 2006 15:30:53 -0000
@@ -666,12 +666,17 @@ chroot ${_user:+-u $_user }${_group:+-g 
 $_chroot $command $rc_flags $command_args"
 			else
 				_doit="\
-${_chdir:+cd $_chdir; }\
-${_nice:+nice -n $_nice }\
+${_chdir:+cd $_chdir && }\
 $command $rc_flags $command_args"
 				if [ -n "$_user" ]; then
 				    _doit="su -m $_user -c 'sh -c \"$_doit\"'"
 				fi
+				if [ -n "$_nice" ]; then
+					if [ -z "$_user" ]; then
+						_doit="sh -c \"$_doit\""
+					fi	
+					_doit="nice -n $_nice $_doit"
+				fi
 			fi
 
 					# if the cmd failed and force