Add creation of dev/mapper/control to nightly tests.

This works around a problem with using the /tmp directory for
the dev/mapper/control node. The failure I saw was this.
When LVM_TEST_DIR was rooted at /tmp/..., the first dmsetup command would fail with this error:
/tmp/LVMTEST26998.J29FayOVWy/dev/mapper/control: matchpathcon 0020000 failed:

The second dmsetup command would always succeed though. Also, when LVM_TEST_DIR was rooted at /root/..., this failure would not occur.

I stepped through this in gdb and found that mknod was indeed creating the control node correctly, however, matchpathcon would fail. The reason it did not fail the second or subsequent iterations of dmsetup is that the control node was already there, and dmsetup does not try to set the selinux security context in that case. One clue may be in the fact that it seems the default security context for files in /tmp/... is <<none>>:
matchpathcon /root/LVMTEST26998.J29FayOVWy/dev/mapper/control
/root/LVMTEST26998.J29FayOVWy/dev/mapper/control system_u:object_r:admin_home_t:s0
matchpathcon /tmp/LVMTEST26998.J29FayOVWy/dev/mapper/control
/tmp/LVMTEST26998.J29FayOVWy/dev/mapper/control <<none>>
matchpathcon /tmp/LVMTEST26998.J29FayOVWy/dev/mapper/control
/tmp/LVMTEST26998.J29FayOVWy/dev/mapper/control <<none>>
matchpathcon /dev/mapper/control
/dev/mapper/control system_u:object_r:lvm_control_t:s0

I would imagine this is why the matchpathcon() call fails. There may be a better fix for this but at this point for the nightly tests we can create the 'control' node explicitly.

---
 test/test-utils.sh |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

index c2755c6..92b5047 100644
@@ -83,6 +83,8 @@ prepare_testroot() {
 	export LVM_SYSTEM_DIR=$TESTDIR/etc
 	export DM_DEV_DIR=$TESTDIR/dev
 	mkdir $LVM_SYSTEM_DIR $DM_DEV_DIR $DM_DEV_DIR/mapper $TESTDIR/lib
+	minor=`cat /proc/misc | grep device-mapper | awk '{print $1}'`
+	mknod $DM_DEV_DIR/mapper/control c 10 $minor
 
 	cd $TESTDIR
 

1.6.2.5

So after creating the subdir in /tmp, set its selinux label to something more appropriate.

Alasdair

Sure - I will work on a better patch.