repack_bootimg.py - LeafOS-Project/android_system_tools_mkbootimg - Gitiles

 #!/usr/bin/env python3
 #
 # Copyright 2021, The Android Open Source Project
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #     http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.

 """Repacks the boot image.

 Unpacks the boot image and the ramdisk inside, then add files into
 the ramdisk to repack the boot image.
 """

 import argparse
 import datetime
 import enum
 import glob
 import os
 import shlex
 import shutil
 import subprocess
 import tempfile


 class TempFileManager:
     """Manages temporary files and dirs."""

     def __init__(self):
         self._temp_files = []

     def __del__(self):
         """Removes temp dirs and files."""
         for f in self._temp_files:
             if os.path.isdir(f):
                 shutil.rmtree(f, ignore_errors=True)
             else:
                 os.remove(f)

     def make_temp_dir(self, prefix='tmp', suffix=''):
         """Makes a temporary dir that will be cleaned up in the destructor.

         Returns:
             The absolute pathname of the new directory.
         """
         dir_name = tempfile.mkdtemp(prefix=prefix, suffix=suffix)
         self._temp_files.append(dir_name)
         return dir_name

     def make_temp_file(self, prefix='tmp', suffix=''):
         """Make a temp file that will be deleted in the destructor.

         Returns:
             The absolute pathname of the new file.
         """
         fd, file_name = tempfile.mkstemp(prefix=prefix, suffix=suffix)
         os.close(fd)
         self._temp_files.append(file_name)
         return file_name


 class RamdiskFormat(enum.Enum):
     """Enum class for different ramdisk compression formats."""
     LZ4 = 1
     GZIP = 2


 class BootImageType(enum.Enum):
     """Enum class for different boot image types."""
     BOOT_IMAGE = 1
     VENDOR_BOOT_IMAGE = 2
     SINGLE_RAMDISK_FRAGMENT = 3
     MULTIPLE_RAMDISK_FRAGMENTS = 4


 class RamdiskImage:
     """A class that supports packing/unpacking a ramdisk."""
     def __init__(self, ramdisk_img, unpack=True):
         self._ramdisk_img = ramdisk_img
         self._ramdisk_format = None
         self._ramdisk_dir = None
         self._temp_file_manager = TempFileManager()

         if unpack:
             self._unpack_ramdisk()
         else:
             self._ramdisk_dir = self._temp_file_manager.make_temp_dir(
                 suffix='_new_ramdisk')

     def _unpack_ramdisk(self):
         """Unpacks the ramdisk."""
         self._ramdisk_dir = self._temp_file_manager.make_temp_dir(
             suffix='_' + os.path.basename(self._ramdisk_img))

         # The compression format might be in 'lz4' or 'gzip' format,
         # trying lz4 first.
         for compression_type, compression_util in [
             (RamdiskFormat.LZ4, 'lz4'),
             (RamdiskFormat.GZIP, 'minigzip')]:

             # Command arguments:
             #   -d: decompression
             #   -c: write to stdout
             decompression_cmd = [
                 compression_util, '-d', '-c', self._ramdisk_img]

             decompressed_result = subprocess.run(
                 decompression_cmd, check=False, capture_output=True)

             if decompressed_result.returncode == 0:
                 self._ramdisk_format = compression_type
                 break

         if self._ramdisk_format is not None:
             # toybox cpio arguments:
             #   -i: extract files from stdin
             #   -d: create directories if needed
             #   -u: override existing files
             subprocess.run(
                 ['toybox', 'cpio', '-idu'], check=True,
                 input=decompressed_result.stdout, cwd=self._ramdisk_dir)

             print("=== Unpacked ramdisk: '{}' ===".format(
                 self._ramdisk_img))
         else:
             raise RuntimeError('Failed to decompress ramdisk.')

     def repack_ramdisk(self, out_ramdisk_file):
         """Repacks a ramdisk from self._ramdisk_dir.

         Args:
             out_ramdisk_file: the output ramdisk file to save.
         """
         compression_cmd = ['lz4', '-l', '-12', '--favor-decSpeed']
         if self._ramdisk_format == RamdiskFormat.GZIP:
             compression_cmd = ['minigzip']

         print('Repacking ramdisk, which might take a few seconds ...')

         mkbootfs_result = subprocess.run(
             ['mkbootfs', self._ramdisk_dir], check=True, capture_output=True)

         with open(out_ramdisk_file, 'w') as output_fd:
             subprocess.run(compression_cmd, check=True,
                            input=mkbootfs_result.stdout, stdout=output_fd)

         print("=== Repacked ramdisk: '{}' ===".format(out_ramdisk_file))

     @property
     def ramdisk_dir(self):
         """Returns the internal ramdisk dir."""
         return self._ramdisk_dir


 class BootImage:
     """A class that supports packing/unpacking a boot.img and ramdisk."""

     def __init__(self, bootimg):
         self._bootimg = bootimg
         self._bootimg_dir = None
         self._bootimg_type = None
         self._ramdisk = None
         self._previous_mkbootimg_args = []
         self._temp_file_manager = TempFileManager()

         self._unpack_bootimg()

     def _get_vendor_ramdisks(self):
         """Returns a list of vendor ramdisks after unpack."""
         return sorted(glob.glob(
             os.path.join(self._bootimg_dir, 'vendor_ramdisk*')))

     def _unpack_bootimg(self):
         """Unpacks the boot.img and the ramdisk inside."""
         self._bootimg_dir = self._temp_file_manager.make_temp_dir(
             suffix='_' + os.path.basename(self._bootimg))

         # Unpacks the boot.img first.
         unpack_bootimg_cmds = [
             'unpack_bootimg',
             '--boot_img', self._bootimg,
             '--out', self._bootimg_dir,
             '--format=mkbootimg',
         ]
         result = subprocess.run(unpack_bootimg_cmds, check=True,
                                 capture_output=True, encoding='utf-8')
         ignore_next = False
         for arg in shlex.split(result.stdout):
             if ignore_next:
                 ignore_next = False
                 continue
             # Skips the original ramdisk since we'll pack a new ramdisk.
             if arg in {'--ramdisk', '--vendor_ramdisk'}:
                 ignore_next = True
                 continue
             self._previous_mkbootimg_args.append(arg)

         print("=== Unpacked boot image: '{}' ===".format(self._bootimg))

         # From the output dir, checks there is 'ramdisk' or 'vendor_ramdisk'.
         ramdisk = os.path.join(self._bootimg_dir, 'ramdisk')
         vendor_ramdisk = os.path.join(self._bootimg_dir, 'vendor_ramdisk')
         vendor_ramdisks = self._get_vendor_ramdisks()
         if os.path.exists(ramdisk):
             self._ramdisk = RamdiskImage(ramdisk)
             self._bootimg_type = BootImageType.BOOT_IMAGE
         elif os.path.exists(vendor_ramdisk):
             self._ramdisk = RamdiskImage(vendor_ramdisk)
             self._bootimg_type = BootImageType.VENDOR_BOOT_IMAGE
         elif len(vendor_ramdisks) == 1:
             self._ramdisk = RamdiskImage(vendor_ramdisks[0])
             self._bootimg_type = BootImageType.SINGLE_RAMDISK_FRAGMENT
         elif len(vendor_ramdisks) > 1:
             # Creates an empty RamdiskImage() below, without unpack.
             # We'll then add files into this newly created ramdisk, then pack
             # it with other vendor ramdisks together.
             self._ramdisk = RamdiskImage(ramdisk_img=None, unpack=False)
             self._bootimg_type = BootImageType.MULTIPLE_RAMDISK_FRAGMENTS
         else:
             raise RuntimeError('Both ramdisk and vendor_ramdisk do not exist.')

     def repack_bootimg(self):
         """Repacks the ramdisk and rebuild the boot.img"""

         new_ramdisk = self._temp_file_manager.make_temp_file(
             prefix='ramdisk-patched')
         self._ramdisk.repack_ramdisk(new_ramdisk)

         mkbootimg_cmd = ['mkbootimg']

         # Uses previous mkbootimg args, e.g., --vendor_cmdline, --dtb_offset.
         mkbootimg_cmd.extend(self._previous_mkbootimg_args)

         if self._bootimg_type == BootImageType.BOOT_IMAGE:
             mkbootimg_cmd.extend(['--ramdisk', new_ramdisk])
             mkbootimg_cmd.extend(['--output', self._bootimg])
         elif self._bootimg_type == BootImageType.VENDOR_BOOT_IMAGE:
             mkbootimg_cmd.extend(['--vendor_ramdisk', new_ramdisk])
             mkbootimg_cmd.extend(['--vendor_boot', self._bootimg])
         elif self._bootimg_type == BootImageType.SINGLE_RAMDISK_FRAGMENT:
             ramdisk_index = (
                 mkbootimg_cmd.index('--vendor_ramdisk_fragment') + 1)
             mkbootimg_cmd[ramdisk_index] = new_ramdisk
             mkbootimg_cmd.extend(['--vendor_boot', self._bootimg])
         elif self._bootimg_type == BootImageType.MULTIPLE_RAMDISK_FRAGMENTS:
             mkbootimg_cmd.extend(['--ramdisk_type', 'PLATFORM'])
             ramdisk_name = (
                 'RAMDISK_' +
                 datetime.datetime.now().strftime('%Y-%m-%d_%H:%M:%S'))
             mkbootimg_cmd.extend(['--ramdisk_name', ramdisk_name])
             mkbootimg_cmd.extend(['--vendor_ramdisk_fragment', new_ramdisk])
             mkbootimg_cmd.extend(['--vendor_boot', self._bootimg])

         subprocess.check_call(mkbootimg_cmd)
         print("=== Repacked boot image: '{}' ===".format(self._bootimg))

     def add_files(self, src_dir, files):
         """Copy files from the src_dir into current ramdisk.

         Args:
             src_dir: a source dir containing the files to copy from.
             files: a list of files or src_file:dst_file pairs to copy from
               src_dir to the current ramdisk.
         """
         # Creates missing parent dirs with 0o755.
         original_mask = os.umask(0o022)
         for f in files:
             if ':' in f:
                 src_file = os.path.join(src_dir, f.split(':')[0])
                 dst_file = os.path.join(self.ramdisk_dir, f.split(':')[1])
             else:
                 src_file = os.path.join(src_dir, f)
                 dst_file = os.path.join(self.ramdisk_dir, f)

             dst_dir = os.path.dirname(dst_file)
             if not os.path.exists(dst_dir):
                 print("Creating dir '{}'".format(dst_dir))
                 os.makedirs(dst_dir, 0o755)
             print("Copying file '{}' into '{}'".format(src_file, dst_file))
             shutil.copy2(src_file, dst_file)
         os.umask(original_mask)

     @property
     def ramdisk_dir(self):
         """Returns the internal ramdisk dir."""
         return self._ramdisk.ramdisk_dir


 def _get_repack_usage():
     return """Usage examples:

   * --ramdisk_add

     Specifies a list of files or src_file:dst_file pairs to copy from
     --src_bootimg's ramdisk into --dst_bootimg's ramdisk.

     $ repack_bootimg \\
         --src_bootimg boot-debug-5.4.img --dst_bootimg vendor_boot-debug.img \\
         --ramdisk_add first_stage_ramdisk/userdebug_plat_sepolicy.cil:userdebug_plat_sepolicy.cil

     The above command copies '/first_stage_ramdisk/userdebug_plat_sepolicy.cil'
     from --src_bootimg's ramdisk to '/userdebug_plat_sepolicy.cil' of
     --dst_bootimg's ramdisk, then repacks the --dst_bootimg.

     $ repack_bootimg \\
         --src_bootimg boot-debug-5.4.img --dst_bootimg vendor_boot-debug.img \\
         --ramdisk_add first_stage_ramdisk/userdebug_plat_sepolicy.cil

     This is similar to the previous example, but the source file path and
     destination file path are the same:
         '/first_stage_ramdisk/userdebug_plat_sepolicy.cil'.

     We can also combine both usage together with a list of copy instructions.
     For example:

     $ repack_bootimg \\
         --src_bootimg boot-debug-5.4.img --dst_bootimg vendor_boot-debug.img \\
         --ramdisk_add file1 file2:/subdir/file2 file3
 """


 def _parse_args():
     """Parse command-line options."""
     parser = argparse.ArgumentParser(
         formatter_class=argparse.RawDescriptionHelpFormatter,
         description='Repacks boot, recovery or vendor_boot image by importing'
                     'ramdisk files from --src_bootimg to --dst_bootimg.',
         epilog=_get_repack_usage(),
     )

     parser.add_argument(
         '--src_bootimg', help='filename to source boot image',
         type=str, required=True)
     parser.add_argument(
         '--dst_bootimg', help='filename to destination boot image',
         type=str, required=True)
     parser.add_argument(
         '--ramdisk_add', nargs='+',
         help='a list of files or src_file:dst_file pairs to add into '
              'the ramdisk',
         default=['userdebug_plat_sepolicy.cil']
     )

     return parser.parse_args()


 def main():
     """Parse arguments and repack boot image."""
     args = _parse_args()
     src_bootimg = BootImage(args.src_bootimg)
     dst_bootimg = BootImage(args.dst_bootimg)
     dst_bootimg.add_files(src_bootimg.ramdisk_dir, args.ramdisk_add)
     dst_bootimg.repack_bootimg()


 if __name__ == '__main__':
     main()
	#!/usr/bin/env python3
	#
	# Copyright 2021, The Android Open Source Project
	#
	# Licensed under the Apache License, Version 2.0 (the "License");
	# you may not use this file except in compliance with the License.
	# You may obtain a copy of the License at
	#
	# http://www.apache.org/licenses/LICENSE-2.0
	#
	# Unless required by applicable law or agreed to in writing, software
	# distributed under the License is distributed on an "AS IS" BASIS,
	# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	# See the License for the specific language governing permissions and
	# limitations under the License.

	"""Repacks the boot image.

	Unpacks the boot image and the ramdisk inside, then add files into
	the ramdisk to repack the boot image.
	"""

	import argparse
	import datetime
	import enum
	import glob
	import os
	import shlex
	import shutil
	import subprocess
	import tempfile


	class TempFileManager:
	"""Manages temporary files and dirs."""

	def __init__(self):
	self._temp_files = []

	def __del__(self):
	"""Removes temp dirs and files."""
	for f in self._temp_files:
	if os.path.isdir(f):
	shutil.rmtree(f, ignore_errors=True)
	else:
	os.remove(f)

	def make_temp_dir(self, prefix='tmp', suffix=''):
	"""Makes a temporary dir that will be cleaned up in the destructor.

	Returns:
	The absolute pathname of the new directory.
	"""
	dir_name = tempfile.mkdtemp(prefix=prefix, suffix=suffix)
	self._temp_files.append(dir_name)
	return dir_name

	def make_temp_file(self, prefix='tmp', suffix=''):
	"""Make a temp file that will be deleted in the destructor.

	Returns:
	The absolute pathname of the new file.
	"""
	fd, file_name = tempfile.mkstemp(prefix=prefix, suffix=suffix)
	os.close(fd)
	self._temp_files.append(file_name)
	return file_name


	class RamdiskFormat(enum.Enum):
	"""Enum class for different ramdisk compression formats."""
	LZ4 = 1
	GZIP = 2


	class BootImageType(enum.Enum):
	"""Enum class for different boot image types."""
	BOOT_IMAGE = 1
	VENDOR_BOOT_IMAGE = 2
	SINGLE_RAMDISK_FRAGMENT = 3
	MULTIPLE_RAMDISK_FRAGMENTS = 4


	class RamdiskImage:
	"""A class that supports packing/unpacking a ramdisk."""
	def __init__(self, ramdisk_img, unpack=True):
	self._ramdisk_img = ramdisk_img
	self._ramdisk_format = None
	self._ramdisk_dir = None
	self._temp_file_manager = TempFileManager()

	if unpack:
	self._unpack_ramdisk()
	else:
	self._ramdisk_dir = self._temp_file_manager.make_temp_dir(
	suffix='_new_ramdisk')

	def _unpack_ramdisk(self):
	"""Unpacks the ramdisk."""
	self._ramdisk_dir = self._temp_file_manager.make_temp_dir(
	suffix='_' + os.path.basename(self._ramdisk_img))

	# The compression format might be in 'lz4' or 'gzip' format,
	# trying lz4 first.
	for compression_type, compression_util in [
	(RamdiskFormat.LZ4, 'lz4'),
	(RamdiskFormat.GZIP, 'minigzip')]:

	# Command arguments:
	# -d: decompression
	# -c: write to stdout
	decompression_cmd = [
	compression_util, '-d', '-c', self._ramdisk_img]

	decompressed_result = subprocess.run(
	decompression_cmd, check=False, capture_output=True)

	if decompressed_result.returncode == 0:
	self._ramdisk_format = compression_type
	break

	if self._ramdisk_format is not None:
	# toybox cpio arguments:
	# -i: extract files from stdin
	# -d: create directories if needed
	# -u: override existing files
	subprocess.run(
	['toybox', 'cpio', '-idu'], check=True,
	input=decompressed_result.stdout, cwd=self._ramdisk_dir)

	print("=== Unpacked ramdisk: '{}' ===".format(
	self._ramdisk_img))
	else:
	raise RuntimeError('Failed to decompress ramdisk.')

	def repack_ramdisk(self, out_ramdisk_file):
	"""Repacks a ramdisk from self._ramdisk_dir.

	Args:
	out_ramdisk_file: the output ramdisk file to save.
	"""
	compression_cmd = ['lz4', '-l', '-12', '--favor-decSpeed']
	if self._ramdisk_format == RamdiskFormat.GZIP:
	compression_cmd = ['minigzip']

	print('Repacking ramdisk, which might take a few seconds ...')

	mkbootfs_result = subprocess.run(
	['mkbootfs', self._ramdisk_dir], check=True, capture_output=True)

	with open(out_ramdisk_file, 'w') as output_fd:
	subprocess.run(compression_cmd, check=True,
	input=mkbootfs_result.stdout, stdout=output_fd)

	print("=== Repacked ramdisk: '{}' ===".format(out_ramdisk_file))

	@property
	def ramdisk_dir(self):
	"""Returns the internal ramdisk dir."""
	return self._ramdisk_dir


	class BootImage:
	"""A class that supports packing/unpacking a boot.img and ramdisk."""

	def __init__(self, bootimg):
	self._bootimg = bootimg
	self._bootimg_dir = None
	self._bootimg_type = None
	self._ramdisk = None
	self._previous_mkbootimg_args = []
	self._temp_file_manager = TempFileManager()

	self._unpack_bootimg()

	def _get_vendor_ramdisks(self):
	"""Returns a list of vendor ramdisks after unpack."""
	return sorted(glob.glob(
	os.path.join(self._bootimg_dir, 'vendor_ramdisk*')))

	def _unpack_bootimg(self):
	"""Unpacks the boot.img and the ramdisk inside."""
	self._bootimg_dir = self._temp_file_manager.make_temp_dir(
	suffix='_' + os.path.basename(self._bootimg))

	# Unpacks the boot.img first.
	unpack_bootimg_cmds = [
	'unpack_bootimg',
	'--boot_img', self._bootimg,
	'--out', self._bootimg_dir,
	'--format=mkbootimg',
	]
	result = subprocess.run(unpack_bootimg_cmds, check=True,
	capture_output=True, encoding='utf-8')
	ignore_next = False
	for arg in shlex.split(result.stdout):
	if ignore_next:
	ignore_next = False
	continue
	# Skips the original ramdisk since we'll pack a new ramdisk.
	if arg in {'--ramdisk', '--vendor_ramdisk'}:
	ignore_next = True
	continue
	self._previous_mkbootimg_args.append(arg)

	print("=== Unpacked boot image: '{}' ===".format(self._bootimg))

	# From the output dir, checks there is 'ramdisk' or 'vendor_ramdisk'.
	ramdisk = os.path.join(self._bootimg_dir, 'ramdisk')
	vendor_ramdisk = os.path.join(self._bootimg_dir, 'vendor_ramdisk')
	vendor_ramdisks = self._get_vendor_ramdisks()
	if os.path.exists(ramdisk):
	self._ramdisk = RamdiskImage(ramdisk)
	self._bootimg_type = BootImageType.BOOT_IMAGE
	elif os.path.exists(vendor_ramdisk):
	self._ramdisk = RamdiskImage(vendor_ramdisk)
	self._bootimg_type = BootImageType.VENDOR_BOOT_IMAGE
	elif len(vendor_ramdisks) == 1:
	self._ramdisk = RamdiskImage(vendor_ramdisks[0])
	self._bootimg_type = BootImageType.SINGLE_RAMDISK_FRAGMENT
	elif len(vendor_ramdisks) > 1:
	# Creates an empty RamdiskImage() below, without unpack.
	# We'll then add files into this newly created ramdisk, then pack
	# it with other vendor ramdisks together.
	self._ramdisk = RamdiskImage(ramdisk_img=None, unpack=False)
	self._bootimg_type = BootImageType.MULTIPLE_RAMDISK_FRAGMENTS
	else:
	raise RuntimeError('Both ramdisk and vendor_ramdisk do not exist.')

	def repack_bootimg(self):
	"""Repacks the ramdisk and rebuild the boot.img"""

	new_ramdisk = self._temp_file_manager.make_temp_file(
	prefix='ramdisk-patched')
	self._ramdisk.repack_ramdisk(new_ramdisk)

	mkbootimg_cmd = ['mkbootimg']

	# Uses previous mkbootimg args, e.g., --vendor_cmdline, --dtb_offset.
	mkbootimg_cmd.extend(self._previous_mkbootimg_args)

	if self._bootimg_type == BootImageType.BOOT_IMAGE:
	mkbootimg_cmd.extend(['--ramdisk', new_ramdisk])
	mkbootimg_cmd.extend(['--output', self._bootimg])
	elif self._bootimg_type == BootImageType.VENDOR_BOOT_IMAGE:
	mkbootimg_cmd.extend(['--vendor_ramdisk', new_ramdisk])
	mkbootimg_cmd.extend(['--vendor_boot', self._bootimg])
	elif self._bootimg_type == BootImageType.SINGLE_RAMDISK_FRAGMENT:
	ramdisk_index = (
	mkbootimg_cmd.index('--vendor_ramdisk_fragment') + 1)
	mkbootimg_cmd[ramdisk_index] = new_ramdisk
	mkbootimg_cmd.extend(['--vendor_boot', self._bootimg])
	elif self._bootimg_type == BootImageType.MULTIPLE_RAMDISK_FRAGMENTS:
	mkbootimg_cmd.extend(['--ramdisk_type', 'PLATFORM'])
	ramdisk_name = (
	'RAMDISK_' +
	datetime.datetime.now().strftime('%Y-%m-%d_%H:%M:%S'))
	mkbootimg_cmd.extend(['--ramdisk_name', ramdisk_name])
	mkbootimg_cmd.extend(['--vendor_ramdisk_fragment', new_ramdisk])
	mkbootimg_cmd.extend(['--vendor_boot', self._bootimg])

	subprocess.check_call(mkbootimg_cmd)
	print("=== Repacked boot image: '{}' ===".format(self._bootimg))

	def add_files(self, src_dir, files):
	"""Copy files from the src_dir into current ramdisk.

	Args:
	src_dir: a source dir containing the files to copy from.
	files: a list of files or src_file:dst_file pairs to copy from
	src_dir to the current ramdisk.
	"""
	# Creates missing parent dirs with 0o755.
	original_mask = os.umask(0o022)
	for f in files:
	if ':' in f:
	src_file = os.path.join(src_dir, f.split(':')[0])
	dst_file = os.path.join(self.ramdisk_dir, f.split(':')[1])
	else:
	src_file = os.path.join(src_dir, f)
	dst_file = os.path.join(self.ramdisk_dir, f)

	dst_dir = os.path.dirname(dst_file)
	if not os.path.exists(dst_dir):
	print("Creating dir '{}'".format(dst_dir))
	os.makedirs(dst_dir, 0o755)
	print("Copying file '{}' into '{}'".format(src_file, dst_file))
	shutil.copy2(src_file, dst_file)
	os.umask(original_mask)

	@property
	def ramdisk_dir(self):
	"""Returns the internal ramdisk dir."""
	return self._ramdisk.ramdisk_dir


	def _get_repack_usage():
	return """Usage examples:

	* --ramdisk_add

	Specifies a list of files or src_file:dst_file pairs to copy from
	--src_bootimg's ramdisk into --dst_bootimg's ramdisk.

	$ repack_bootimg \\
	--src_bootimg boot-debug-5.4.img --dst_bootimg vendor_boot-debug.img \\
	--ramdisk_add first_stage_ramdisk/userdebug_plat_sepolicy.cil:userdebug_plat_sepolicy.cil

	The above command copies '/first_stage_ramdisk/userdebug_plat_sepolicy.cil'
	from --src_bootimg's ramdisk to '/userdebug_plat_sepolicy.cil' of
	--dst_bootimg's ramdisk, then repacks the --dst_bootimg.

	$ repack_bootimg \\
	--src_bootimg boot-debug-5.4.img --dst_bootimg vendor_boot-debug.img \\
	--ramdisk_add first_stage_ramdisk/userdebug_plat_sepolicy.cil

	This is similar to the previous example, but the source file path and
	destination file path are the same:
	'/first_stage_ramdisk/userdebug_plat_sepolicy.cil'.

	We can also combine both usage together with a list of copy instructions.
	For example:

	$ repack_bootimg \\
	--src_bootimg boot-debug-5.4.img --dst_bootimg vendor_boot-debug.img \\
	--ramdisk_add file1 file2:/subdir/file2 file3
	"""


	def _parse_args():
	"""Parse command-line options."""
	parser = argparse.ArgumentParser(
	formatter_class=argparse.RawDescriptionHelpFormatter,
	description='Repacks boot, recovery or vendor_boot image by importing'
	'ramdisk files from --src_bootimg to --dst_bootimg.',
	epilog=_get_repack_usage(),
	)

	parser.add_argument(
	'--src_bootimg', help='filename to source boot image',
	type=str, required=True)
	parser.add_argument(
	'--dst_bootimg', help='filename to destination boot image',
	type=str, required=True)
	parser.add_argument(
	'--ramdisk_add', nargs='+',
	help='a list of files or src_file:dst_file pairs to add into '
	'the ramdisk',
	default=['userdebug_plat_sepolicy.cil']
	)

	return parser.parse_args()


	def main():
	"""Parse arguments and repack boot image."""
	args = _parse_args()
	src_bootimg = BootImage(args.src_bootimg)
	dst_bootimg = BootImage(args.dst_bootimg)
	dst_bootimg.add_files(src_bootimg.ramdisk_dir, args.ramdisk_add)
	dst_bootimg.repack_bootimg()


	if __name__ == '__main__':
	main()