common/cgroup

#!/bin/bash
# SPDX-License-Identifier: GPL-3.0+
#
# cgroup helper functions.

. common/shellcheck

_cgroup2_base_dir()
{
	findmnt -ft cgroup2 -no TARGET
}

_init_cgroup2()
{
	CGROUP2_DIR="$(_cgroup2_base_dir)/blktests"
	if ! mkdir "$CGROUP2_DIR"; then
		unset CGROUP2_DIR
		return 1
	fi
	return 0
}

_exit_cgroup2()
{
	if [[ "${CGROUP2_DIR:-}" ]]; then
		find "$CGROUP2_DIR" -type d -delete
		unset CGROUP2_DIR
	fi
}

_have_cgroup2()
{
	if [[ -z $(_cgroup2_base_dir) ]]; then
		SKIP_REASON="cgroup2 is not mounted"
		return 1
	fi
	return 0
}

_have_cgroup2_controller()
{
	local controller="$1"

	_have_cgroup2 || return 1

	dir="$(_cgroup2_base_dir)"

	if ! grep -q "$controller" "$dir/cgroup.controllers"; then
		SKIP_REASON="no support for $controller cgroup controller; if it is enabled, you may need to boot with cgroup_no_v1=$controller"
		return 1
	fi
}

_have_cgroup2_controller_file()
{
	local controller="$1"
	local file="$2"
	local dir

	_have_cgroup2_controller "$controller" || return 1

	mkdir "$dir/blktests"
	echo "+$controller" > "$dir/cgroup.subtree_control"
	if [[ ! -f $dir/blktests/$file ]]; then
		rmdir "$dir/blktests"
		SKIP_REASON="cgroup file $file doesn't exist"
		return 1
	fi
	rmdir "$dir/blktests"
	return 0
}