Bug#397525: initscripts: Remove extra fd usage from mtab init script

[Petter Reinholdtsen]

[David Härdeman]
> the attached patch changes the initscripts mtab script to not use an
> extra fd when processing /proc/mounts. This makes SELinux happier as
> the extra fds aren't "leaked" to the utils that are executed later.

Sounds like a good idea, but I would like to know if it affect the
runtime behaviour or not.

> I must admit though that I didn't really understand why the fd9
> trick was used in the first place?

It is an optimization, to reduce the number of forks needed during
boot.  Will your version increase the number of forks needed?

Friendly,
-- 
Petter Reinholdtsen

Bug#397525: initscripts: Remove extra fd usage from mtab init script

[David Härdeman]

Package: initscripts
Version: 2.86.ds1-34
Severity: minor
Tags: patch

Hi,

the attached patch changes the initscripts mtab script to not use an 
extra fd when processing /proc/mounts. This makes SELinux happier as the 
extra fds aren't "leaked" to the utils that are executed later.


I must admit though that I didn't really understand why the fd9 trick 
was used in the first place?


--
David Härdeman
diff -ur ./sysvinit-2.86.ds1.orig/debian/initscripts/etc/init.d/mtab.sh 
./sysvinit-2.86.ds1/debian/initscripts/etc/init.d/mtab.sh
--- ./sysvinit-2.86.ds1.orig/debian/initscripts/etc/init.d/mtab.sh  
2006-11-07 23:49:09.0 +0100
+++ ./sysvinit-2.86.ds1/debian/initscripts/etc/init.d/mtab.sh   2006-11-07 
23:50:05.0 +0100
@@ -44,7 +44,7 @@
fi
 
# Not mounted?
-   if ! mountpoint -q $2
+   if ! mountpoint -q $2 < /dev/null
then
return
fi
@@ -57,9 +57,9 @@
fi
 
# Already recorded?
-   if ! grep -E -sq "^([^ ]+) +$2 +" /etc/mtab
+   if ! grep -E -sq "^([^ ]+) +$2 +" /etc/mtab < /dev/null
then
-   mount -f -t $1 $OPTS $4 $NAME $2
+   mount -f -t $1 $OPTS $4 $NAME $2 < /dev/null
fi
 }
 
@@ -141,7 +141,6 @@
 
# Add everything else in /proc/mounts into /etc/mtab, with
# special exceptions.
-   exec 9<&0 0