common/sysfs

##/bin/bash
# SPDX-License-Identifier: GPL-2.0+
# Copyright (c) 2025 Oracle.  All Rights Reserved.
#
# Common/sysfs file for the sysfs related helper functions.

# Test for the existence of a policy at /sys/fs/$FSTYP/$DEV/$ATTR
#
# All arguments are necessary, and in this order:
#  - dev: device name, e.g. $SCRATCH_DEV
#  - attr: path name under /sys/fs/$FSTYP/$dev
#  - policy: policy within /sys/fs/$FSTYP/$dev
#
# Usage example:
#   _has_fs_sysfs_attr_policy /dev/mapper/scratch-dev read_policy round-robin
_has_fs_sysfs_attr_policy()
{
	local dev=$1
	local attr=$2
	local policy=$3

	if [ ! -b "$dev" -o -z "$attr" -o -z "$policy" ]; then
		_fail \
	     "Usage: _has_fs_sysfs_attr_policy <mounted_device> <attr> <policy>"
	fi

	local dname=$(_fs_sysfs_dname $dev)
	if ! test -e /sys/fs/${FSTYP}/${dname}/${attr}; then
		return 1
	fi

	cat /sys/fs/${FSTYP}/${dname}/${attr} | grep -q ${policy}
}

# Require the existence of a sysfs entry at /sys/fs/$FSTYP/$DEV/$ATTR
# and value in it contains $policy
# All arguments are necessary, and in this order:
#  - dev: device name, e.g. $SCRATCH_DEV
#  - attr: path name under /sys/fs/$FSTYP/$dev
#  - policy: mentioned in /sys/fs/$FSTYP/$dev/$attr
#
# Usage example:
#   _require_fs_sysfs_attr_policy /dev/mapper/scratch-dev read_policy round-robin
_require_fs_sysfs_attr_policy()
{
	_has_fs_sysfs_attr_policy "$@" && return

	local dev=$1
	local attr=$2
	local policy=$3
	local dname=$(_fs_sysfs_dname $dev)

	_notrun "This test requires /sys/fs/${FSTYP}/${dname}/${attr} ${policy}"
}

_set_sysfs_policy()
{
	local dev=$1
	local attr=$2
	shift
	shift
	local policy=$@

	_set_fs_sysfs_attr $dev $attr ${policy}

	case "$FSTYP" in
	btrfs)
		_get_fs_sysfs_attr $dev $attr | grep -q "[${policy}]"
		if [[ $? != 0 ]]; then
			echo "Setting sysfs $attr $policy failed"
		fi
		;;
	*)
		_fail \
"sysfs syntax verification for '${attr}' '${policy}' for '${FSTYP}' is not implemented"
		;;
	esac
}

_set_sysfs_policy_must_fail()
{
	local dev=$1
	local attr=$2
	shift
	shift
	local policy=$@

	_set_fs_sysfs_attr $dev $attr ${policy} | _filter_sysfs_error \
							   | tee -a $seqres.full
}

# Verify sysfs attribute rejects invalid input.
# Usage syntax:
#   _verify_sysfs_syntax <$dev> <$attr> <$policy> [$value]
# Examples:
#   _verify_sysfs_syntax $TEST_DEV read_policy pid
#   _verify_sysfs_syntax $TEST_DEV read_policy round-robin 4k
# Note:
#  Testcase must include
#      . ./common/filter
# Prerequisite checks are kept outside this function
# to make them clear to the test case, rather than hiding
# them deep inside another function.
#      _require_fs_sysfs_attr_policy $TEST_DEV $attr $policy
_verify_sysfs_syntax()
{
	local dev=$1
	local attr=$2
	local policy=$3
	local value=$4

	# Test policy specified wrongly. Must fail.
	_set_sysfs_policy_must_fail $dev $attr "'$policy $policy'"
	_set_sysfs_policy_must_fail $dev $attr "'$policy t'"
	_set_sysfs_policy_must_fail $dev $attr "' '"
	_set_sysfs_policy_must_fail $dev $attr "'${policy} n'"
	_set_sysfs_policy_must_fail $dev $attr "'n ${policy}'"
	_set_sysfs_policy_must_fail $dev $attr "' ${policy}'"
	_set_sysfs_policy_must_fail $dev $attr "' ${policy} '"
	_set_sysfs_policy_must_fail $dev $attr "'${policy} '"
	_set_sysfs_policy_must_fail $dev $attr _${policy}
	_set_sysfs_policy_must_fail $dev $attr ${policy}_
	_set_sysfs_policy_must_fail $dev $attr _${policy}_
	_set_sysfs_policy_must_fail $dev $attr ${policy}:
	# Test policy longer than 32 chars fails stable.
	_set_sysfs_policy_must_fail $dev $attr 'jfdkkkkjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjffjfjfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff'

	# Test policy specified correctly. Must pass.
	_set_sysfs_policy $dev $attr $policy

	# If the policy has no value return
	if [[ -z $value ]]; then
		return
	fi

	# Test value specified wrongly. Must fail.
	_set_sysfs_policy_must_fail $dev $attr "'$policy: $value'"
	_set_sysfs_policy_must_fail $dev $attr "'$policy:$value '"
	_set_sysfs_policy_must_fail $dev $attr "'$policy:$value typo'"
	_set_sysfs_policy_must_fail $dev $attr "'$policy:${value}typo'"
	_set_sysfs_policy_must_fail $dev $attr "'$policy :$value'"

	# Test policy and value all specified correctly. Must pass.
	_set_sysfs_policy $dev $attr $policy:$value
}