tests/generic/699

#! /bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2022 Christian Brauner (Microsoft).  All Rights Reserved.
#
# FS QA Test 698
#
# This's copied from generic/698, extend it to test overlayfs on top of idmapped
# mounts specifically.
#
. ./common/preamble
_begin_fstest auto quick perms attr idmapped mount

# Override the default cleanup function.
_cleanup()
{
	cd /
	_unmount $SCRATCH_MNT/target-mnt
	_unmount $SCRATCH_MNT/ovl-merge 2>/dev/null
	_unmount $SCRATCH_MNT 2>/dev/null
	rm -r -f $tmp.*
}

_exclude_fs overlay
_require_extra_fs overlay

_require_scratch
_require_chown
_require_idmapped_mounts
_require_test_program "vfs/mount-idmapped"
_require_user fsgqa2
_require_group fsgqa2
# Do this SECOND so that qa_user is fsgqa, and _user_do uses that account
_require_user fsgqa
_require_group fsgqa

user_foo=`id -u fsgqa`
group_foo=`id -g fsgqa`
user_bar=`id -u fsgqa2`
group_bar=`id -g fsgqa2`

setup_tree()
{
	mkdir -p $SCRATCH_MNT/source-mnt
	chmod 0777 $SCRATCH_MNT/source-mnt
	touch $SCRATCH_MNT/source-mnt/file1
	chown 65534:65534 $SCRATCH_MNT
	chown 65534:65534 $SCRATCH_MNT/source-mnt
	chown 65534:65535 $SCRATCH_MNT/source-mnt/file1

	mkdir -p $SCRATCH_MNT/target-mnt
	chmod 0777 $SCRATCH_MNT/target-mnt
}

# Setup an idmapped mount where uid and gid 65534 are mapped to fsgqa and uid
# and gid 65535 are mapped to fsgqa2.
setup_idmapped_mnt()
{
	$here/src/vfs/mount-idmapped \
		--map-mount=u:65534:$user_foo:1 \
		--map-mount=g:65534:$group_foo:1 \
		--map-mount=u:65535:$user_bar:1 \
		--map-mount=g:65535:$group_bar:1 \
		$SCRATCH_MNT/source-mnt $SCRATCH_MNT/target-mnt
}

# We've created a layout where fsgqa owns the target file but the group of the
# target file is owned by another group. We now test that user fsgqa can change
# the group ownership of the file to a group they control. In this case to the
# fsgqa group.
change_group_ownership()
{
	local path="$1"

	stat -c '%U:%G' $path
	_user_do "id -u --name; id -g --name; chgrp $group_foo $path"
	stat -c '%U:%G' $path
	_user_do "id -u --name; id -g --name; chgrp $group_bar $path > /dev/null 2>&1"
	stat -c '%U:%G' $path
}

lower="$SCRATCH_MNT/target-mnt"
upper="$SCRATCH_MNT/ovl-upper"
work="$SCRATCH_MNT/ovl-work"
merge="$SCRATCH_MNT/ovl-merge"

reset_ownership()
{
	local path="$SCRATCH_MNT/source-mnt/file1"

	echo ""
	echo "reset ownership"
	chown 65534:65534 $path
	stat -c '%u:%g' $path
	chown 65534:65535 $path
	stat -c '%u:%g' $path
}

setup_overlayfs()
{
	mkdir -p $upper $work $merge
	_mount -t overlay -o lowerdir=$lower,upperdir=$upper,workdir=$work \
		overlay $merge $*
}

# Prepare overlayfs with metacopy turned off.
setup_overlayfs_idmapped_lower_metacopy_off()
{
	setup_overlayfs -ometacopy=off || \
	    _notrun "overlayfs doesn't support idmappped layers"
}

# Prepare overlayfs with metacopy turned on.
setup_overlayfs_idmapped_lower_metacopy_on()
{
	setup_overlayfs -ometacopy=on
}

reset_overlayfs()
{
	_unmount $SCRATCH_MNT/ovl-merge 2>/dev/null
	rm -rf $upper $work $merge
}

# Overlayfs can be mounted on top of idmapped layers. Make sure that the basic
# test explained in the comment for change_group_ownership() passes with
# overlayfs mounted on top of it.
# This tests overlayfs with metacopy turned off, i.e., changing a file copies
# up data and metadata.
run_overlayfs_idmapped_lower_metacopy_off()
{
	echo ""
	echo "overlayfs idmapped lower metacopy off"
	change_group_ownership "$SCRATCH_MNT/ovl-merge/file1"
	reset_overlayfs
	reset_ownership
}

# Overlayfs can be mounted on top of idmapped layers. Make sure that the basic
# test explained in the comment for change_group_ownership() passes with
# overlayfs mounted on top of it.
# This tests overlayfs with metacopy turned on, i.e., changing a file tries to
# only copy up metadata.
run_overlayfs_idmapped_lower_metacopy_on()
{
	echo ""
	echo "overlayfs idmapped lower metacopy on"
	change_group_ownership "$SCRATCH_MNT/ovl-merge/file1"
	reset_overlayfs
	reset_ownership
}

_scratch_mkfs >> $seqres.full
_scratch_mount
_supports_filetype $SCRATCH_MNT || _notrun "overlayfs test requires d_type"

setup_tree
setup_idmapped_mnt
setup_overlayfs_idmapped_lower_metacopy_off
run_overlayfs_idmapped_lower_metacopy_off

setup_overlayfs_idmapped_lower_metacopy_on
run_overlayfs_idmapped_lower_metacopy_on

# success, all done
status=0
exit