zephyr/scripts/west_commands/sign.py

354 lines
14 KiB
Python

# Copyright (c) 2018 Foundries.io
#
# SPDX-License-Identifier: Apache-2.0
import abc
import argparse
import os
import pathlib
import shutil
import subprocess
import sys
from west import log
from west.util import quote_sh_list
from build_helpers import find_build_dir, is_zephyr_build, \
FIND_BUILD_DIR_DESCRIPTION
from runners.core import BuildConfiguration
from zcmake import CMakeCache
from zephyr_ext_common import Forceable, cached_runner_config
# FIXME we should think of a nicer way to manage sys.path
# for shared Zephyr code.
sys.path.append(os.path.join(os.environ['ZEPHYR_BASE'], 'scripts', 'dts'))
import edtlib
SIGN_DESCRIPTION = '''\
This command automates some of the drudgery of creating signed Zephyr
binaries for chain-loading by a bootloader.
In the simplest usage, run this from your build directory:
west sign -t your_tool -- ARGS_FOR_YOUR_TOOL
Assuming your binary was properly built for processing and handling by
tool "your_tool", this creates zephyr.signed.bin and zephyr.signed.hex
files (if supported by "your_tool") which are ready for use by your
bootloader. The "ARGS_FOR_YOUR_TOOL" value can be any additional
arguments you want to pass to the tool, such as the location of a
signing key, a version identifier, etc.
See tool-specific help below for details.'''
SIGN_EPILOG = '''\
imgtool
-------
Currently, MCUboot's 'imgtool' tool is supported. To build a signed
binary you can load with MCUboot using imgtool, run this from your
build directory:
west sign -t imgtool -- --key YOUR_SIGNING_KEY.pem
For this to work, either imgtool must be installed (e.g. using pip3),
or you must pass the path to imgtool.py using the -p option.
The image header size, alignment, and slot sizes are determined from
the build directory using .config and the device tree. A default
version number of 0.0.0+0 is used (which can be overridden by passing
"--version x.y.z+w" after "--key"). As shown above, extra arguments
after a '--' are passed to imgtool directly.'''
class ToggleAction(argparse.Action):
def __call__(self, parser, args, ignored, option):
setattr(args, self.dest, not option.startswith('--no-'))
class Sign(Forceable):
def __init__(self):
super(Sign, self).__init__(
'sign',
# Keep this in sync with the string in west-commands.yml.
'sign a Zephyr binary for bootloader chain-loading',
SIGN_DESCRIPTION,
accepts_unknown_args=False)
def do_add_parser(self, parser_adder):
parser = parser_adder.add_parser(
self.name,
epilog=SIGN_EPILOG,
help=self.help,
formatter_class=argparse.RawDescriptionHelpFormatter,
description=self.description)
parser.add_argument('-d', '--build-dir',
help=FIND_BUILD_DIR_DESCRIPTION)
self.add_force_arg(parser)
# general options
group = parser.add_argument_group('tool control options')
group.add_argument('-t', '--tool', choices=['imgtool'], required=True,
help='''image signing tool name; only imgtool is
currently supported''')
group.add_argument('-p', '--tool-path', default=None,
help='''path to the tool itself, if needed''')
group.add_argument('tool_args', nargs='*', metavar='tool_opt',
help='extra option(s) to pass to the signing tool')
# bin file options
group = parser.add_argument_group('binary (.bin) file options')
group.add_argument('--bin', '--no-bin', dest='gen_bin', nargs=0,
action=ToggleAction,
help='''produce a signed .bin file?
(default: yes, if supported and unsigned bin
exists)''')
group.add_argument('-B', '--sbin', metavar='BIN',
help='''signed .bin file name
(default: zephyr.signed.bin in the build
directory, next to zephyr.bin)''')
# hex file options
group = parser.add_argument_group('Intel HEX (.hex) file options')
group.add_argument('--hex', '--no-hex', dest='gen_hex', nargs=0,
action=ToggleAction,
help='''produce a signed .hex file?
(default: yes, if supported and unsigned hex
exists)''')
group.add_argument('-H', '--shex', metavar='HEX',
help='''signed .hex file name
(default: zephyr.signed.hex in the build
directory, next to zephyr.hex)''')
return parser
def do_run(self, args, ignored):
self.args = args # for check_force
# Find the build directory and parse .config and DT.
build_dir = find_build_dir(args.build_dir)
self.check_force(os.path.isdir(build_dir),
'no such build directory {}'.format(build_dir))
self.check_force(is_zephyr_build(build_dir),
"build directory {} doesn't look like a Zephyr build "
'directory'.format(build_dir))
bcfg = BuildConfiguration(build_dir)
# Decide on output formats.
formats = []
bin_exists = 'CONFIG_BUILD_OUTPUT_BIN' in bcfg
if args.gen_bin:
self.check_force(bin_exists,
'--bin given but CONFIG_BUILD_OUTPUT_BIN not set '
"in build directory's ({}) .config".
format(build_dir))
formats.append('bin')
elif args.gen_bin is None and bin_exists:
formats.append('bin')
hex_exists = 'CONFIG_BUILD_OUTPUT_HEX' in bcfg
if args.gen_hex:
self.check_force(hex_exists,
'--hex given but CONFIG_BUILD_OUTPUT_HEX not set '
"in build directory's ({}) .config".
format(build_dir))
formats.append('hex')
elif args.gen_hex is None and hex_exists:
formats.append('hex')
if not formats:
log.dbg('nothing to do: no output files')
return
# Delegate to the signer.
if args.tool == 'imgtool':
signer = ImgtoolSigner()
# (Add support for other signers here in elif blocks)
else:
raise RuntimeError("can't happen")
signer.sign(self, build_dir, bcfg, formats)
class Signer(abc.ABC):
'''Common abstract superclass for signers.
To add support for a new tool, subclass this and add support for
it in the Sign.do_run() method.'''
@abc.abstractmethod
def sign(self, command, build_dir, bcfg, formats):
'''Abstract method to perform a signature; subclasses must implement.
:param command: the Sign instance
:param build_dir: the build directory
:param bcfg: BuildConfiguration for build directory
:param formats: list of formats to generate ('bin', 'hex')
'''
class ImgtoolSigner(Signer):
def sign(self, command, build_dir, bcfg, formats):
if not formats:
return
args = command.args
b = pathlib.Path(build_dir)
cache = CMakeCache.from_build_dir(build_dir)
tool_path = self.find_imgtool(command, args)
# The vector table offset is set in Kconfig:
vtoff = self.get_cfg(command, bcfg, 'CONFIG_TEXT_SECTION_OFFSET')
# Flash device write alignment and the partition's slot size
# come from devicetree:
flash = self.edt_flash_node(b, cache)
align, addr, size = self.edt_flash_params(flash)
runner_config = cached_runner_config(build_dir, cache)
if 'bin' in formats:
in_bin = runner_config.bin_file
if not in_bin:
log.die("can't find unsigned .bin to sign")
else:
in_bin = None
if 'hex' in formats:
in_hex = runner_config.hex_file
if not in_hex:
log.die("can't find unsigned .hex to sign")
else:
in_hex = None
log.banner('image configuration:')
log.inf('partition offset: {0} (0x{0:x})'.format(addr))
log.inf('partition size: {0} (0x{0:x})'.format(size))
log.inf('text section offset: {0} (0x{0:x})'.format(vtoff))
# Base sign command.
#
# We provide a default --version in case the user is just
# messing around and doesn't want to set one. It will be
# overridden if there is a --version in args.tool_args.
sign_base = [tool_path, 'sign',
'--version', '0.0.0+0',
'--align', str(align),
'--header-size', str(vtoff),
'--slot-size', str(size)]
sign_base.extend(args.tool_args)
log.banner('signed binaries:')
if in_bin:
out_bin = args.sbin or str(b / 'zephyr' / 'zephyr.signed.bin')
sign_bin = sign_base + [in_bin, out_bin]
log.inf('bin: {}'.format(out_bin))
log.dbg(quote_sh_list(sign_bin))
subprocess.check_call(sign_bin)
if in_hex:
out_hex = args.shex or str(b / 'zephyr' / 'zephyr.signed.hex')
sign_hex = sign_base + [in_hex, out_hex]
log.inf('hex: {}'.format(out_hex))
log.dbg(quote_sh_list(sign_hex))
subprocess.check_call(sign_hex)
@staticmethod
def find_imgtool(command, args):
if args.tool_path:
command.check_force(shutil.which(args.tool_path),
'--tool-path {}: not an executable'.
format(args.tool_path))
tool_path = args.tool_path
else:
tool_path = shutil.which('imgtool') or shutil.which('imgtool.py')
if not tool_path:
log.die('imgtool not found; either install it',
'(e.g. "pip3 install imgtool") or provide --tool-path')
return tool_path
@staticmethod
def get_cfg(command, bcfg, item):
try:
return bcfg[item]
except KeyError:
command.check_force(
False, "build .config is missing a {} value".format(item))
return None
@staticmethod
def edt_flash_node(b, cache):
# Get the EDT Node corresponding to the zephyr,flash chosen DT
# node.
# Retrieve the list of devicetree bindings from cache.
try:
bindings = cache.get_list('CACHED_DTS_ROOT_BINDINGS')
log.dbg('DTS bindings:', bindings, level=log.VERBOSE_VERY)
except KeyError:
log.die('CMake cache has no CACHED_DTS_ROOT_BINDINGS.'
'\n Try again after re-building your application.')
# Ensure the build directory has a compiled DTS file
# where we expect it to be.
dts = b / 'zephyr' / (cache['CACHED_BOARD'] + '.dts.pre.tmp')
if not dts.is_file():
log.die("can't find DTS; expected:", dts)
log.dbg('DTS file:', dts, level=log.VERBOSE_VERY)
# Parse the devicetree using bindings from cache.
try:
edt = edtlib.EDT(dts, bindings)
except edtlib.EDTError as e:
log.die("can't parse devicetree:", e)
# By convention, the zephyr,flash chosen node contains the
# partition information about the zephyr image to sign.
flash = edt.chosen_node('zephyr,flash')
if not flash:
log.die('devicetree has no chosen zephyr,flash node;',
"can't infer flash write block or image-0 slot sizes")
return flash
@staticmethod
def edt_flash_params(flash):
# Get the flash device's write alignment and the image-0
# partition's size out of the build directory's devicetree.
# The node must have a "partitions" child node, which in turn
# must have a child node labeled "image-0". By convention, the
# primary slot for consumption by imgtool is linked into this
# partition.
if 'partitions' not in flash.children:
log.die("DT zephyr,flash chosen node has no partitions,",
"can't find partition for MCUboot slot 0")
for node in flash.children['partitions'].children.values():
if node.label == 'image-0':
image_0 = node
break
else:
log.die("DT zephyr,flash chosen node has no image-0 partition,",
"can't determine its size")
# The partitions node, and its subnode, must provide
# the size of the image-0 partition via the regs property.
if not image_0.regs:
log.die('image-0 flash partition has no regs property;',
"can't determine size of image slot 0")
# Die on missing or zero alignment or slot_size.
if "write-block-size" not in flash.props:
log.die('DT zephyr,flash node has no write-block-size;',
"can't determine imgtool write alignment")
align = flash.props['write-block-size'].val
if align == 0:
log.die('expected nonzero flash alignment, but got '
'DT flash device write-block-size {}'.format(align))
reg = image_0.regs[0]
if reg.size == 0:
log.die('expected nonzero slot size, but got '
'DT image-0 partition size {}'.format(reg.size))
return (align, reg.addr, reg.size)