On Mon, Apr 07, 2025 at 11:48:18AM +0800, Anand Jain wrote:
> Introduce `verify_sysfs_syntax()` and `_require_fs_sysfs_attr_policy()`
> to verify whether a sysfs attribute rejects invalid input arguments
> during writes.
>
> Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
> ---
> common/sysfs | 141 +++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 141 insertions(+)
> create mode 100644 common/sysfs
>
> diff --git a/common/sysfs b/common/sysfs
> new file mode 100644
> index 000000000000..9f2d77c6b1f5
> --- /dev/null
> +++ b/common/sysfs
> @@ -0,0 +1,141 @@
> +##/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
Shouldn't this return 1 if the parameters are not fully specified?
> +
> + local dname=$(_fs_sysfs_dname $dev)
> + test -e /sys/fs/${FSTYP}/${dname}/${attr}
What is the point of testing path existence here if the function doesn't
actually change its behavior?
> +
> + 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:
> +# Process must call . ./common/filter
> +_verify_sysfs_syntax()
> +{
> + local dev=$1
> + local attr=$2
> + local policy=$3
> + local value=$4
> +
> + # Do this in the test case so that we know its prerequisites.
> + # '_require_fs_sysfs_attr_policy $TEST_DEV $attr $policy'
But it's commented out ... ?
--D
> +
> + # 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
> +}
> --
> 2.47.0
>
>
