mount_options.tc

  1#!/bin/sh
  2# SPDX-License-Identifier: GPL-2.0
  3# description: Test tracefs GID mount option
  4# requires: "[gid=<gid>]":README
  5
  6fail() {
  7	local msg="$1"
  8
  9	echo "FAILED: $msg"
 10	exit_fail
 11}
 12
 13find_alternate_gid() {
 14	local original_gid="$1"
 15	tac /etc/group | grep -v ":$original_gid:" | head -1 | cut -d: -f3
 16}
 17
 18remount_tracefs_with_options() {
 19	local mount_point="$1"
 20	local options="$2"
 21
 22	mount -t tracefs -o "remount,$options" nodev "$mount_point"
 23
 24	setup
 25}
 26
 27unmount_tracefs() {
 28	local mount_point="$1"
 29
 30	# Need to make sure the mount isn't busy so that we can umount it
 31	(cd $mount_point; finish_system;)
 32
 33	cleanup
 34}
 35
 36create_instance() {
 37	local mount_point="$1"
 38	local instance="$mount_point/instances/$(mktemp -u test-XXXXXX)"
 39
 40	mkdir "$instance"
 41	echo "$instance"
 42}
 43
 44remove_instance() {
 45	local instance="$1"
 46
 47	rmdir "$instance"
 48}
 49
 50check_gid() {
 51	local mount_point="$1"
 52	local expected_gid="$2"
 53
 54	echo "Checking permission group ..."
 55
 56	cd "$mount_point"
 57
 58	for file in "." "events" "events/sched" "events/sched/sched_switch" "events/sched/sched_switch/enable"; do
 59		local gid=`stat -c "%g" $file`
 60		if [ "$gid" -ne "$expected_gid" ]; then
 61			cd - # Return to the previous working directory (tracefs root)
 62			fail "$(realpath $file): Expected group $expected_gid; Got group $gid"
 63		fi
 64	done
 65
 66	cd - # Return to the previous working directory (tracefs root)
 67}
 68
 69test_gid_mount_option() {
 70	local mount_point=$(get_mount_point)
 71	local mount_options=$(get_mnt_options "$mount_point")
 72	local original_group=$(stat -c "%g" .)
 73	local other_group=$(find_alternate_gid "$original_group")
 74
 75	# Set up mount options with new GID for testing
 76	local new_options=`echo "$mount_options" | sed -e "s/gid=[0-9]*/gid=$other_group/"`
 77	if [ "$new_options" = "$mount_options" ]; then
 78		new_options="$mount_options,gid=$other_group"
 79		mount_options="$mount_options,gid=$original_group"
 80	fi
 81
 82	# Unmount existing tracefs instance and mount with new GID
 83	unmount_tracefs "$mount_point"
 84	remount_tracefs_with_options "$mount_point" "$new_options"
 85
 86	check_gid "$mount_point" "$other_group"
 87
 88	# Check that files created after the mount inherit the GID
 89	local instance=$(create_instance "$mount_point")
 90	check_gid "$instance" "$other_group"
 91	remove_instance "$instance"
 92
 93	# Unmount and remount with the original GID
 94	unmount_tracefs "$mount_point"
 95	remount_tracefs_with_options "$mount_point" "$mount_options"
 96	check_gid "$mount_point" "$original_group"
 97}
 98
 99test_gid_mount_option
100
101exit 0