qemu/tests/qemu-iotests/060

#!/bin/bash
#
# Test case for image corruption (overlapping data structures) in qcow2
#
# Copyright (C) 2013 Red Hat, Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

# creator
owner=mreitz@redhat.com

seq=`basename $0`
echo "QA output created by $seq"

here=`pwd`
tmp=/tmp/$$
status=1	# failure is the default!

_cleanup()
{
	_cleanup_test_img
}
trap "_cleanup; exit \$status" 0 1 2 3 15

# get standard environment, filters and checks
. ./common.rc
. ./common.filter

# This tests qocw2-specific low-level functionality
_supported_fmt qcow2
_supported_proto generic
_supported_os Linux

rt_offset=65536  # 0x10000 (XXX: just an assumption)
rb_offset=131072 # 0x20000 (XXX: just an assumption)
l1_offset=196608 # 0x30000 (XXX: just an assumption)
l2_offset=262144 # 0x40000 (XXX: just an assumption)

IMGOPTS="compat=1.1"

echo
echo "=== Testing L2 reference into L1 ==="
echo
_make_test_img 64M
# Link first L1 entry (first L2 table) onto itself
# (Note the MSb in the L1 entry is set, ensuring the refcount is one - else any
# later write will result in a COW operation, effectively ruining this attempt
# on image corruption)
poke_file "$TEST_IMG" "$l1_offset" "\x80\x00\x00\x00\x00\x03\x00\x00"
_check_test_img

# The corrupt bit should not be set anyway
./qcow2.py "$TEST_IMG" dump-header | grep incompatible_features

# Try to write something, thereby forcing the corrupt bit to be set
$QEMU_IO -c "write -P 0x2a 0 512" "$TEST_IMG" | _filter_qemu_io

# The corrupt bit must now be set
./qcow2.py "$TEST_IMG" dump-header | grep incompatible_features

# Try to open the image R/W (which should fail)
$QEMU_IO -c "read 0 512" "$TEST_IMG" 2>&1 | _filter_qemu_io | _filter_testdir | _filter_imgfmt

# Try to open it RO (which should succeed)
$QEMU_IO -c "read 0 512" -r "$TEST_IMG" | _filter_qemu_io

# We could now try to fix the image, but this would probably fail (how should an
# L2 table linked onto the L1 table be fixed?)

echo
echo "=== Testing cluster data reference into refcount block ==="
echo
_make_test_img 64M
# Allocate L2 table
truncate -s "$(($l2_offset+65536))" "$TEST_IMG"
poke_file "$TEST_IMG" "$l1_offset" "\x80\x00\x00\x00\x00\x04\x00\x00"
# Mark cluster as used
poke_file "$TEST_IMG" "$(($rb_offset+8))" "\x00\x01"
# Redirect new data cluster onto refcount block
poke_file "$TEST_IMG" "$l2_offset" "\x80\x00\x00\x00\x00\x02\x00\x00"
_check_test_img
./qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
$QEMU_IO -c "write -P 0x2a 0 512" "$TEST_IMG" | _filter_qemu_io
./qcow2.py "$TEST_IMG" dump-header | grep incompatible_features

# Try to fix it
_check_test_img -r all

# The corrupt bit should be cleared
./qcow2.py "$TEST_IMG" dump-header | grep incompatible_features

# Look if it's really really fixed
$QEMU_IO -c "write -P 0x2a 0 512" "$TEST_IMG" | _filter_qemu_io
./qcow2.py "$TEST_IMG" dump-header | grep incompatible_features

# success, all done
echo "*** done"
rm -f $seq.full
status=0