tests/qemu-iotests/common.filter - qemu - Git at Google

 #!/usr/bin/env bash
 #
 # Copyright (C) 2009 Red Hat, Inc.
 # Copyright (c) 2000-2001 Silicon Graphics, Inc.  All Rights Reserved.
 #
 # 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.
 #
 # This program is distributed in the hope that it would 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/>.
 #
 #
 # standard filters
 #

 _filter_date()
 {
     $SED -re 's/[0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2}:[0-9]{2}/yyyy-mm-dd hh:mm:ss/'
 }

 _filter_vmstate_size()
 {
     $SED -r -e 's/[0-9. ]{5} [KMGT]iB/     SIZE/' \
             -e 's/[0-9. ]{5} B/   SIZE/'
 }

 _filter_generated_node_ids()
 {
     $SED -re 's/\#block[0-9]{3,}/NODE_NAME/'
 }

 _filter_qom_path()
 {
     $SED -e '/Attached to:/s/\device[[0-9]\+\]/device[N]/g'
 }

 # replace occurrences of the actual TEST_DIR value with TEST_DIR
 _filter_testdir()
 {
     $SED -e "s#$TEST_DIR/#TEST_DIR/#g" \
          -e "s#$SOCK_DIR/#SOCK_DIR/#g" \
          -e "s#SOCK_DIR/fuse-#TEST_DIR/#g"
 }

 # replace occurrences of the actual IMGFMT value with IMGFMT
 _filter_imgfmt()
 {
     $SED -e "s#$IMGFMT#IMGFMT#g"
 }

 # Replace error message when the format is not supported and delete
 # the output lines after the first one
 _filter_qemu_img_check()
 {
     $SED -e '/allocated.*fragmented.*compressed clusters/d' \
         -e 's/qemu-img: This image format does not support checks/No errors were found on the image./' \
         -e '/Image end offset: [0-9]\+/d'
 }

 # Removes \r from messages
 _filter_win32()
 {
     $SED -e 's/\r//g'
 }

 # sanitize qemu-io output
 _filter_qemu_io()
 {
     _filter_win32 | $SED -e "s/[0-9]* ops\; [0-9/:. sec]* ([0-9/.inf]* [EPTGMKiBbytes]*\/sec and [0-9/.inf]* ops\/sec)/X ops\; XX:XX:XX.X (XXX YYY\/sec and XXX ops\/sec)/" \
         -e "s/: line [0-9][0-9]*:  *[0-9][0-9]*\( Aborted\| Killed\)/:\1/" \
         -e "s/qemu-io> //g"
 }

 # replace occurrences of QEMU_PROG with "qemu"
 _filter_qemu()
 {
     $SED -e "s#\\(^\\|(qemu) \\)$(basename $QEMU_PROG):#\1QEMU_PROG:#" \
         -e 's#^QEMU [0-9]\+\.[0-9]\+\.[0-9]\+ monitor#QEMU X.Y.Z monitor#' \
         -e $'s#\r##' # QEMU monitor uses \r\n line endings
 }

 # replace problematic QMP output like timestamps
 _filter_qmp()
 {
     _filter_win32 | \
     $SED -e 's#\("\(micro\)\?seconds": \)[0-9]\+#\1 TIMESTAMP#g' \
         -e 's#^{"QMP":.*}$#QMP_VERSION#' \
         -e '/^    "QMP": {\s*$/, /^    }\s*$/ c\' \
         -e '    QMP_VERSION'
 }

 # readline makes HMP command strings so long that git complains
 _filter_hmp()
 {
     $SED -e $'s/^\\((qemu) \\)\\?.*\e\\[D/\\1/g' \
         -e $'s/\e\\[K//g'
 }

 # replace block job offset
 _filter_block_job_offset()
 {
     $SED -e 's/, "offset": [0-9]\+,/, "offset": OFFSET,/'
 }

 # replace block job len
 _filter_block_job_len()
 {
     $SED -e 's/, "len": [0-9]\+,/, "len": LEN,/g'
 }

 # replace actual image size (depends on the host filesystem)
 _filter_actual_image_size()
 {
     $SED -s 's/\("actual-size":\s*\)[0-9]\+/\1SIZE/g'
 }

 # Filename filters for qemu-img create
 _filter_img_create_filenames()
 {
     $SED \
         -e "s#$REMOTE_TEST_DIR#TEST_DIR#g" \
         -e "s#$IMGPROTO:$TEST_DIR#TEST_DIR#g" \
         -e "s#$TEST_DIR#TEST_DIR#g" \
         -e "s#$SOCK_DIR#SOCK_DIR#g" \
         -e 's#SOCK_DIR/fuse-#TEST_DIR/#g' \
         -e "s#$IMGFMT#IMGFMT#g" \
         -e 's#nbd:127.0.0.1:[0-9]\\+#TEST_DIR/t.IMGFMT#g' \
         -e 's#nbd+unix:///\??socket=SOCK_DIR/nbd#TEST_DIR/t.IMGFMT#g'
 }

 # replace driver-specific options in the "Formatting..." line
 _do_filter_img_create()
 {
     # Split the line into the pre-options part ($filename_part, which
     # precedes ", fmt=") and the options part ($options, which starts
     # with "fmt=")
     # (And just echo everything before the first "^Formatting")
     readarray formatting_line < <($SED -e 's/, fmt=/\n/')

     filename_part=${formatting_line[0]}
     unset formatting_line[0]

     options="fmt=${formatting_line[@]}"

     # Set grep_data_file to '\|data_file' to keep it; make it empty
     # to drop it.
     # We want to drop it if it is part of the global $IMGOPTS, and we
     # want to keep it otherwise (if the test specifically wants to
     # test data files).
     grep_data_file=(-e data_file)
     if _get_data_file "$TEST_IMG" > /dev/null; then
         grep_data_file=()
     fi

     filename_part=$(echo "$filename_part" | _filter_img_create_filenames)

     # Break the option line before each option (preserving pre-existing
     # line breaks by replacing them by \0 and restoring them at the end),
     # then filter out the options we want to keep and sort them according
     # to some order that all block drivers used at the time of writing
     # this function.
     options=$(
         echo "$options" \
         | tr '\n' '\0' \
         | $SED -e 's/ \([a-z0-9_.-]*\)=/\n\1=/g' \
         | grep -a -e '^fmt' -e '^size' -e '^backing' -e '^preallocation' \
                   -e '^encryption' "${grep_data_file[@]}" \
         | _filter_img_create_filenames \
         | $SED \
             -e 's/^\(fmt\)/0-\1/' \
             -e 's/^\(size\)/1-\1/' \
             -e 's/^\(backing\)/2-\1/' \
             -e 's/^\(data_file\)/3-\1/' \
             -e 's/^\(encryption\)/4-\1/' \
             -e 's/^\(preallocation\)/8-\1/' \
         | LC_ALL=C sort \
         | $SED -e 's/^[0-9]-//' \
         | tr '\n\0' ' \n' \
         | $SED -e 's/^ *$//' -e 's/ *$//'
     )

     if [ -n "$options" ]; then
         echo "$filename_part, $options"
     elif [ -n "$filename_part" ]; then
         echo "$filename_part"
     fi
 }

 # Filter qemu-img create output:
 # Pipe all ^Formatting lines through _do_filter_img_create, and all
 # other lines through _filter_img_create_filenames
 _filter_img_create()
 {
     while read -r line; do
         if echo "$line" | grep -q '^Formatting'; then
             echo "$line" | _do_filter_img_create
         else
             echo "$line" | _filter_img_create_filenames
         fi
     done
 }

 _filter_img_create_size()
 {
     $SED -e "s# size=[0-9]\\+# size=SIZE#g"
 }

 _filter_img_info()
 {
     if [[ "$1" == "--format-specific" ]]; then
         local format_specific=1
         shift
     else
         local format_specific=0
     fi

     discard=0
     regex_json_spec_start='^ *"format-specific": \{'
     $SED -e "s#$REMOTE_TEST_DIR#TEST_DIR#g" \
         -e "s#$IMGPROTO:$TEST_DIR#TEST_DIR#g" \
         -e "s#$TEST_DIR#TEST_DIR#g" \
         -e "s#$SOCK_DIR#SOCK_DIR#g" \
         -e "s#$IMGFMT#IMGFMT#g" \
         -e 's#nbd://127.0.0.1:[0-9]\\+$#TEST_DIR/t.IMGFMT#g' \
         -e 's#nbd+unix:///\??socket=SOCK_DIR/nbd#TEST_DIR/t.IMGFMT#g' \
         -e 's#SOCK_DIR/fuse-#TEST_DIR/#g' \
         -e "/encrypted: yes/d" \
         -e "/cluster_size: [0-9]\\+/d" \
         -e "/table_size: [0-9]\\+/d" \
         -e "/compat: '[^']*'/d" \
         -e "/compat6: \\(on\\|off\\)/d" \
         -e "s/cid: [0-9]\+/cid: XXXXXXXXXX/" \
         -e "/static: \\(on\\|off\\)/d" \
         -e "/zeroed_grain: \\(on\\|off\\)/d" \
         -e "/subformat: '[^']*'/d" \
         -e "/adapter_type: '[^']*'/d" \
         -e "/hwversion: '[^']*'/d" \
         -e "/lazy_refcounts: \\(on\\|off\\)/d" \
         -e "/extended_l2=\\(on\\|off\\)/d" \
         -e "/block_size: [0-9]\\+/d" \
         -e "/block_state_zero: \\(on\\|off\\)/d" \
         -e "/log_size: [0-9]\\+/d" \
         -e "s/iters: [0-9]\\+/iters: 1024/" \
         -e "s/uuid: [-a-f0-9]\\+/uuid: 00000000-0000-0000-0000-000000000000/" | \
     while IFS='' read -r line; do
         if [[ $format_specific == 1 ]]; then
             discard=0
         elif [[ $line == "Format specific information:" ]]; then
             discard=1
         elif [[ $line =~ $regex_json_spec_start ]]; then
             discard=2
             regex_json_spec_end="^${line%%[^ ]*}\\},? *$"
         fi
         if [[ $discard == 0 ]]; then
             echo "$line"
         elif [[ $discard == 1 && ! $line ]]; then
             echo
             discard=0
         elif [[ $discard == 2 && $line =~ $regex_json_spec_end ]]; then
             discard=0
         fi
     done
 }

 # filter out offsets and file names from qemu-img map; good for both
 # human and json output
 _filter_qemu_img_map()
 {
     # Assuming the data_file value in $IMGOPTS contains a '$TEST_IMG',
     # create a filter that replaces the data file name by $TEST_IMG.
     # Example:
     #   In $IMGOPTS: 'data_file=$TEST_IMG.data_file'
     #   Then data_file_pattern == '\(.*\).data_file'
     #   And  data_file_filter  == -e 's#\(.*\).data_file#\1#
     data_file_filter=()
     if data_file_pattern=$(_get_data_file '\\(.*\\)'); then
         data_file_filter=(-e "s#$data_file_pattern#\\1#")
     fi

     $SED -e 's/\([0-9a-fx]* *[0-9a-fx]* *\)[0-9a-fx]* */\1/g' \
         -e 's/"offset": [0-9]\+/"offset": OFFSET/g' \
         -e 's/Mapped to *//' \
         "${data_file_filter[@]}" \
         | _filter_testdir | _filter_imgfmt
 }

 _filter_nbd()
 {
     # nbd.c error messages contain function names and line numbers that are
     # prone to change.  Message ordering depends on timing between send and
     # receive callbacks sometimes, making them unreliable.
     #
     # Filter out the TCP port number since this changes between runs.
     $SED -e '/nbd\/.*\.c:/d' \
         -e 's#127\.0\.0\.1:[0-9]*#127.0.0.1:PORT#g' \
         -e "s#?socket=$SOCK_DIR#?socket=SOCK_DIR#g" \
         -e 's#\(foo\|PORT/\?\|.sock\): Failed to .*$#\1#'
 }

 _filter_qmp_empty_return()
 {
     grep -v '{"return": {}}'
 }

 _filter_json_filename()
 {
     $PYTHON -c 'import sys
 result, *fnames = sys.stdin.read().split("json:{")
 depth = 0
 for fname in fnames:
     depth += 1 # For the opening brace in the split separator
     for chr_i, chr in enumerate(fname):
         if chr == "{":
             depth += 1
         elif chr == "}":
             depth -= 1
             if depth == 0:
                 break

     # json:{} filenames may be nested; filter out everything from
     # inside the outermost one
     if depth == 0:
         chr_i += 1 # First character past the filename
         result += "json:{ /* filtered */ }" + fname[chr_i:]

 sys.stdout.write(result)'
 }

 # make sure this script returns success
 true
	#!/usr/bin/env bash
	#
	# Copyright (C) 2009 Red Hat, Inc.
	# Copyright (c) 2000-2001 Silicon Graphics, Inc. All Rights Reserved.
	#
	# 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.
	#
	# This program is distributed in the hope that it would 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/>.
	#
	#
	# standard filters
	#

	_filter_date()
	{
	$SED -re 's/[0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2}:[0-9]{2}/yyyy-mm-dd hh:mm:ss/'
	}

	_filter_vmstate_size()
	{
	$SED -r -e 's/[0-9. ]{5} [KMGT]iB/ SIZE/' \
	-e 's/[0-9. ]{5} B/ SIZE/'
	}

	_filter_generated_node_ids()
	{
	$SED -re 's/\#block[0-9]{3,}/NODE_NAME/'
	}

	_filter_qom_path()
	{
	$SED -e '/Attached to:/s/\device[[0-9]\+\]/device[N]/g'
	}

	# replace occurrences of the actual TEST_DIR value with TEST_DIR
	_filter_testdir()
	{
	$SED -e "s#$TEST_DIR/#TEST_DIR/#g" \
	-e "s#$SOCK_DIR/#SOCK_DIR/#g" \
	-e "s#SOCK_DIR/fuse-#TEST_DIR/#g"
	}

	# replace occurrences of the actual IMGFMT value with IMGFMT
	_filter_imgfmt()
	{
	$SED -e "s#$IMGFMT#IMGFMT#g"
	}

	# Replace error message when the format is not supported and delete
	# the output lines after the first one
	_filter_qemu_img_check()
	{
	$SED -e '/allocated.fragmented.compressed clusters/d' \
	-e 's/qemu-img: This image format does not support checks/No errors were found on the image./' \
	-e '/Image end offset: [0-9]\+/d'
	}

	# Removes \r from messages
	_filter_win32()
	{
	$SED -e 's/\r//g'
	}

	# sanitize qemu-io output
	_filter_qemu_io()
	{
	_filter_win32 \| $SED -e "s/[0-9]* ops\; [0-9/:. sec]* ([0-9/.inf]* [EPTGMKiBbytes]\/sec and [0-9/.inf] ops\/sec)/X ops\; XX:XX:XX.X (XXX YYY\/sec and XXX ops\/sec)/" \
	-e "s/: line [0-9][0-9]: [0-9][0-9]*\( Aborted\\| Killed\)/:\1/" \
	-e "s/qemu-io> //g"
	}

	# replace occurrences of QEMU_PROG with "qemu"
	_filter_qemu()
	{
	$SED -e "s#\\(^\\\|(qemu) \\)$(basename $QEMU_PROG):#\1QEMU_PROG:#" \
	-e 's#^QEMU [0-9]\+\.[0-9]\+\.[0-9]\+ monitor#QEMU X.Y.Z monitor#' \
	-e $'s#\r##' # QEMU monitor uses \r\n line endings
	}

	# replace problematic QMP output like timestamps
	_filter_qmp()
	{
	_filter_win32 \| \
	$SED -e 's#\("\(micro\)\?seconds": \)[0-9]\+#\1 TIMESTAMP#g' \
	-e 's#^{"QMP":.*}$#QMP_VERSION#' \
	-e '/^ "QMP": {\s$/, /^ }\s$/ c\' \
	-e ' QMP_VERSION'
	}

	# readline makes HMP command strings so long that git complains
	_filter_hmp()
	{
	$SED -e $'s/^\\((qemu) \\)\\?.*\e\\[D/\\1/g' \
	-e $'s/\e\\[K//g'
	}

	# replace block job offset
	_filter_block_job_offset()
	{
	$SED -e 's/, "offset": [0-9]\+,/, "offset": OFFSET,/'
	}

	# replace block job len
	_filter_block_job_len()
	{
	$SED -e 's/, "len": [0-9]\+,/, "len": LEN,/g'
	}

	# replace actual image size (depends on the host filesystem)
	_filter_actual_image_size()
	{
	$SED -s 's/\("actual-size":\s*\)[0-9]\+/\1SIZE/g'
	}

	# Filename filters for qemu-img create
	_filter_img_create_filenames()
	{
	$SED \
	-e "s#$REMOTE_TEST_DIR#TEST_DIR#g" \
	-e "s#$IMGPROTO:$TEST_DIR#TEST_DIR#g" \
	-e "s#$TEST_DIR#TEST_DIR#g" \
	-e "s#$SOCK_DIR#SOCK_DIR#g" \
	-e 's#SOCK_DIR/fuse-#TEST_DIR/#g' \
	-e "s#$IMGFMT#IMGFMT#g" \
	-e 's#nbd:127.0.0.1:[0-9]\\+#TEST_DIR/t.IMGFMT#g' \
	-e 's#nbd+unix:///\??socket=SOCK_DIR/nbd#TEST_DIR/t.IMGFMT#g'
	}

	# replace driver-specific options in the "Formatting..." line
	_do_filter_img_create()
	{
	# Split the line into the pre-options part ($filename_part, which
	# precedes ", fmt=") and the options part ($options, which starts
	# with "fmt=")
	# (And just echo everything before the first "^Formatting")
	readarray formatting_line < <($SED -e 's/, fmt=/\n/')

	filename_part=${formatting_line[0]}
	unset formatting_line[0]

	options="fmt=${formatting_line[@]}"

	# Set grep_data_file to '\\|data_file' to keep it; make it empty
	# to drop it.
	# We want to drop it if it is part of the global $IMGOPTS, and we
	# want to keep it otherwise (if the test specifically wants to
	# test data files).
	grep_data_file=(-e data_file)
	if _get_data_file "$TEST_IMG" > /dev/null; then
	grep_data_file=()
	fi

	filename_part=$(echo "$filename_part" \| _filter_img_create_filenames)

	# Break the option line before each option (preserving pre-existing
	# line breaks by replacing them by \0 and restoring them at the end),
	# then filter out the options we want to keep and sort them according
	# to some order that all block drivers used at the time of writing
	# this function.
	options=$(
	echo "$options" \
	\| tr '\n' '\0' \
	\| $SED -e 's/ \([a-z0-9_.-]*\)=/\n\1=/g' \
	\| grep -a -e '^fmt' -e '^size' -e '^backing' -e '^preallocation' \
	-e '^encryption' "${grep_data_file[@]}" \
	\| _filter_img_create_filenames \
	\| $SED \
	-e 's/^\(fmt\)/0-\1/' \
	-e 's/^\(size\)/1-\1/' \
	-e 's/^\(backing\)/2-\1/' \
	-e 's/^\(data_file\)/3-\1/' \
	-e 's/^\(encryption\)/4-\1/' \
	-e 's/^\(preallocation\)/8-\1/' \
	\| LC_ALL=C sort \
	\| $SED -e 's/^[0-9]-//' \
	\| tr '\n\0' ' \n' \
	\| $SED -e 's/^ $//' -e 's/ $//'
	)

	if [ -n "$options" ]; then
	echo "$filename_part, $options"
	elif [ -n "$filename_part" ]; then
	echo "$filename_part"
	fi
	}

	# Filter qemu-img create output:
	# Pipe all ^Formatting lines through _do_filter_img_create, and all
	# other lines through _filter_img_create_filenames
	_filter_img_create()
	{
	while read -r line; do
	if echo "$line" \| grep -q '^Formatting'; then
	echo "$line" \| _do_filter_img_create
	else
	echo "$line" \| _filter_img_create_filenames
	fi
	done
	}

	_filter_img_create_size()
	{
	$SED -e "s# size=[0-9]\\+# size=SIZE#g"
	}

	_filter_img_info()
	{
	if [[ "$1" == "--format-specific" ]]; then
	local format_specific=1
	shift
	else
	local format_specific=0
	fi

	discard=0
	regex_json_spec_start='^ *"format-specific": \{'
	$SED -e "s#$REMOTE_TEST_DIR#TEST_DIR#g" \
	-e "s#$IMGPROTO:$TEST_DIR#TEST_DIR#g" \
	-e "s#$TEST_DIR#TEST_DIR#g" \
	-e "s#$SOCK_DIR#SOCK_DIR#g" \
	-e "s#$IMGFMT#IMGFMT#g" \
	-e 's#nbd://127.0.0.1:[0-9]\\+$#TEST_DIR/t.IMGFMT#g' \
	-e 's#nbd+unix:///\??socket=SOCK_DIR/nbd#TEST_DIR/t.IMGFMT#g' \
	-e 's#SOCK_DIR/fuse-#TEST_DIR/#g' \
	-e "/encrypted: yes/d" \
	-e "/cluster_size: [0-9]\\+/d" \
	-e "/table_size: [0-9]\\+/d" \
	-e "/compat: '[^']*'/d" \
	-e "/compat6: \\(on\\\|off\\)/d" \
	-e "s/cid: [0-9]\+/cid: XXXXXXXXXX/" \
	-e "/static: \\(on\\\|off\\)/d" \
	-e "/zeroed_grain: \\(on\\\|off\\)/d" \
	-e "/subformat: '[^']*'/d" \
	-e "/adapter_type: '[^']*'/d" \
	-e "/hwversion: '[^']*'/d" \
	-e "/lazy_refcounts: \\(on\\\|off\\)/d" \
	-e "/extended_l2=\\(on\\\|off\\)/d" \
	-e "/block_size: [0-9]\\+/d" \
	-e "/block_state_zero: \\(on\\\|off\\)/d" \
	-e "/log_size: [0-9]\\+/d" \
	-e "s/iters: [0-9]\\+/iters: 1024/" \
	-e "s/uuid: [-a-f0-9]\\+/uuid: 00000000-0000-0000-0000-000000000000/" \| \
	while IFS='' read -r line; do
	if [[ $format_specific == 1 ]]; then
	discard=0
	elif [[ $line == "Format specific information:" ]]; then
	discard=1
	elif [[ $line =~ $regex_json_spec_start ]]; then
	discard=2
	regex_json_spec_end="^${line%%[^ ]}\\},? $"
	fi
	if [[ $discard == 0 ]]; then
	echo "$line"
	elif [[ $discard == 1 && ! $line ]]; then
	echo
	discard=0
	elif [[ $discard == 2 && $line =~ $regex_json_spec_end ]]; then
	discard=0
	fi
	done
	}

	# filter out offsets and file names from qemu-img map; good for both
	# human and json output
	_filter_qemu_img_map()
	{
	# Assuming the data_file value in $IMGOPTS contains a '$TEST_IMG',
	# create a filter that replaces the data file name by $TEST_IMG.
	# Example:
	# In $IMGOPTS: 'data_file=$TEST_IMG.data_file'
	# Then data_file_pattern == '\(.*\).data_file'
	# And data_file_filter == -e 's#\(.*\).data_file#\1#
	data_file_filter=()
	if data_file_pattern=$(_get_data_file '\\(.*\\)'); then
	data_file_filter=(-e "s#$data_file_pattern#\\1#")
	fi

	$SED -e 's/\([0-9a-fx]* [0-9a-fx] \)[0-9a-fx] */\1/g' \
	-e 's/"offset": [0-9]\+/"offset": OFFSET/g' \
	-e 's/Mapped to *//' \
	"${data_file_filter[@]}" \
	\| _filter_testdir \| _filter_imgfmt
	}

	_filter_nbd()
	{
	# nbd.c error messages contain function names and line numbers that are
	# prone to change. Message ordering depends on timing between send and
	# receive callbacks sometimes, making them unreliable.
	#
	# Filter out the TCP port number since this changes between runs.
	$SED -e '/nbd\/.*\.c:/d' \
	-e 's#127\.0\.0\.1:[0-9]*#127.0.0.1:PORT#g' \
	-e "s#?socket=$SOCK_DIR#?socket=SOCK_DIR#g" \
	-e 's#\(foo\\|PORT/\?\\|.sock\): Failed to .*$#\1#'
	}

	_filter_qmp_empty_return()
	{
	grep -v '{"return": {}}'
	}

	_filter_json_filename()
	{
	$PYTHON -c 'import sys
	result, *fnames = sys.stdin.read().split("json:{")
	depth = 0
	for fname in fnames:
	depth += 1 # For the opening brace in the split separator
	for chr_i, chr in enumerate(fname):
	if chr == "{":
	depth += 1
	elif chr == "}":
	depth -= 1
	if depth == 0:
	break

	# json:{} filenames may be nested; filter out everything from
	# inside the outermost one
	if depth == 0:
	chr_i += 1 # First character past the filename
	result += "json:{ /* filtered */ }" + fname[chr_i:]

	sys.stdout.write(result)'
	}

	# make sure this script returns success
	true