#!/bin/sh
# ----------------------------------------------------------------------
#    Copyright (c) 2017 Canonical Ltd. (All rights reserved)
#
#    This program is free software; you can redistribute it and/or
#    modify it under the terms of version 2 of the GNU General Public
#    License published by the Free Software Foundation.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program. If not, see <http://www.gnu.org/licenses/>.
# ----------------------------------------------------------------------

APPARMOR_FUNCTIONS=/lib/apparmor/rc.apparmor.functions
APPARMORFS=/sys/kernel/security/apparmor
PROFILES="${APPARMORFS}/profiles"
REMOVE="${APPARMORFS}/.remove"

DRY_RUN=0

. $APPARMOR_FUNCTIONS

usage() {
	local progname="$0"
	local rc="$1"
	local msg="usage: ${progname} [options]

Remove profiles unknown to the system

Options:
 -h, --help	Show this help message and exit
 -n		Dry run; don't remove profiles"

	if [ "$rc" -ne 0 ] ; then
		echo "$msg" 1>&2
	else
		echo "$msg"
	fi

	exit "$rc"
}

if [ "$#" -gt 1 ] ; then
	usage 1
elif [ "$#" -eq 1 ] ; then
	if [ "$1" = "-h" -o "$1" = "--help" ] ; then
		usage 0
	elif [ "$1" = "-n" ] ; then
		DRY_RUN=1
	else
		usage 1
	fi
fi


# We can't use a -r test here because while $PROFILES is world-readable,
# apparmorfs may still return EACCES from open()
#
# We have to do this check because error checking awk's getline() below is
# tricky and, as is, results in an infinite loop when apparmorfs returns an
# error from open().
if ! IFS= read line < "$PROFILES" ; then
	echo "ERROR: Unable to read apparmorfs profiles file" 1>&2
	exit 1
elif [ ! -w "$REMOVE" ] ; then
	echo "ERROR: Unable to write to apparmorfs remove file" 1>&2
	exit 1
fi

# Clean out running profiles not associated with the current profile
# set, excluding the libvirt dynamically generated profiles.
# Note that we reverse sort the list of profiles to remove to
# ensure that child profiles (e.g. hats) are removed before the
# parent. We *do* need to remove the child profile and not rely
# on removing the parent profile when the profile has had its
# child profile names changed.

LOADED_PROFILES=$("$PARSER" -N $PROFILE_DIRS) || {
	ret=$?
	echo 'apparmor_parser exited with failure, aborting.' >&2
	exit $ret
}

echo "$LOADED_PROFILES" | awk '
BEGIN {
  while (getline < "'${PROFILES}'" ) {
    str = sub(/ \((enforce|complain)\)$/, "", $0);
    if (match($0, /^libvirt-[0-9a-f\-]+$/) == 0)
      arr[$str] = $str
  }
}

{ if (length(arr[$0]) > 0) { delete arr[$0] } }

END {
  for (key in arr)
    if (length(arr[key]) > 0) {
      printf("%s\n", arr[key])
    }
}
' | LC_COLLATE=C sort -r | \
	while IFS= read profile ; do
		if [ "$DRY_RUN" -ne 0 ]; then
			echo "Would remove '${profile}'"
		else
			echo "Removing '${profile}'"
			echo -n "$profile" > "${REMOVE}"
		fi
	done

# will not catch all errors, but still better than nothing
exit $?
