mkbootimg: turn into a python script

Turn mkbootimg into a python script instead of a C utility

Change-Id: I36d35dfacfbbef2cc16bd6695ab15ee716bb0cdb

mkbootimg/Android.mk

@@ -2,12 +2,10 @@
 LOCAL_PATH:= $(call my-dir)
 include $(CLEAR_VARS)
 
-LOCAL_SRC_FILES := mkbootimg.c
-LOCAL_STATIC_LIBRARIES := libmincrypt
-LOCAL_CFLAGS := -Werror
+LOCAL_SRC_FILES := mkbootimg
+LOCAL_MODULE_CLASS := EXECUTABLES
+LOCAL_IS_HOST_MODULE := true
 
 LOCAL_MODULE := mkbootimg
 
-include $(BUILD_HOST_EXECUTABLE)
-
-$(call dist-for-goals,dist_files,$(LOCAL_BUILT_MODULE))
+include $(BUILD_PREBUILT)

mkbootimg/mkbootimg

@@ -0,0 +1,136 @@
+#!/usr/bin/env python
+# Copyright 2015, 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.
+
+from __future__ import print_function
+from sys import argv, exit, stderr
+from argparse import ArgumentParser, FileType, Action
+from os import fstat
+from struct import pack
+from hashlib import sha1
+
+def filesize(f):
+    if f is None:
+        return 0
+    try:
+        return fstat(f.fileno()).st_size
+    except OSError:
+        return 0
+
+
+def update_sha(sha, f):
+    if f:
+        sha.update(f.read())
+        f.seek(0)
+        sha.update(pack('I', filesize(f)))
+    else:
+        sha.update(pack('I', 0))
+
+
+def pad_file(f, padding):
+    pad = (padding - (f.tell() & (padding - 1))) & (padding - 1)
+    f.write(pack(str(pad) + 'x'))
+
+
+def write_header(args):
+    BOOT_MAGIC = 'ANDROID!'.encode()
+    args.output.write(pack('8s', BOOT_MAGIC))
+    args.output.write(pack('8I',
+        filesize(args.kernel),                          # size in bytes
+        args.base + args.kernel_offset,                 # physical load addr
+        filesize(args.ramdisk),                         # size in bytes
+        args.base + args.ramdisk_offset,                # physical load addr
+        filesize(args.second),                          # size in bytes
+        args.base + args.second_offset,                 # physical load addr
+        args.base + args.tags_offset,                   # physical addr for kernel tags
+        args.pagesize))                                 # flash page size we assume
+    args.output.write(pack('8x'))                       # future expansion: should be 0
+    args.output.write(pack('16s', args.board.encode())) # asciiz product name
+    args.output.write(pack('512s', args.cmdline[:512].encode()))
+
+    sha = sha1()
+    update_sha(sha, args.kernel)
+    update_sha(sha, args.ramdisk)
+    update_sha(sha, args.second)
+    img_id = pack('32s', sha.digest())
+
+    args.output.write(img_id)
+    args.output.write(pack('1024s', args.cmdline[512:].encode()))
+    pad_file(args.output, args.pagesize)
+    return img_id
+
+
+class ValidateStrLenAction(Action):
+    def __init__(self, option_strings, dest, nargs=None, **kwargs):
+        if 'maxlen' not in kwargs:
+            raise ValueError('maxlen must be set')
+        self.maxlen = int(kwargs['maxlen'])
+        del kwargs['maxlen']
+        super(ValidateStrLenAction, self).__init__(option_strings, dest, **kwargs)
+
+    def __call__(self, parser, namespace, values, option_string=None):
+        if len(values) > self.maxlen:
+            raise ValueError('String argument too long: max {0:d}, got {1:d}'.
+                format(self.maxlen, len(values)))
+        setattr(namespace, self.dest, values)
+
+
+def write_padded_file(f_out, f_in, padding):
+    if f_in is None:
+        return
+    f_out.write(f_in.read())
+    pad_file(f_out, padding)
+
+
+def parse_cmdline():
+    parser = ArgumentParser()
+    parser.add_argument('--kernel', help='path to the kernel', type=FileType('rb'),
+                        required=True)
+    parser.add_argument('--ramdisk', help='path to the ramdisk', type=FileType('rb'))
+    parser.add_argument('--second', help='path to the 2nd bootloader', type=FileType('rb'))
+    parser.add_argument('--cmdline', help='extra arguments to be passed on the '
+                        'kernel command line', default='', action=ValidateStrLenAction, maxlen=1536)
+    parser.add_argument('--base', help='base address', type=int, default=0x10000000)
+    parser.add_argument('----kernel_offset', help='kernel offset', type=int, default=0x00008000)
+    parser.add_argument('--ramdisk_offset', help='ramdisk offset', type=int, default=0x01000000)
+    parser.add_argument('--second_offset', help='2nd bootloader offset', type=int,
+                        default=0x00f00000)
+    parser.add_argument('--tags_offset', help='tags offset', type=int, default=0x00000100)
+    parser.add_argument('--board', help='board name', default='', action=ValidateStrLenAction,
+                        maxlen=16)
+    parser.add_argument('--pagesize', help='page size', type=int,
+                        choices=[2**i for i in range(11,15)], default=2048)
+    parser.add_argument('--id', help='print the image ID on standard output',
+                        action='store_true')
+    parser.add_argument('-o', '--output', help='output file name', type=FileType('wb'),
+                        required=True)
+    return parser.parse_args()
+
+
+def write_data(args):
+    write_padded_file(args.output, args.kernel, args.pagesize)
+    write_padded_file(args.output, args.ramdisk, args.pagesize)
+    write_padded_file(args.output, args.second, args.pagesize)
+
+
+def main():
+    args = parse_cmdline()
+    img_id = write_header(args)
+    write_data(args)
+    if args.id:
+        print('0x' + ''.join('{:02x}'.format(ord(c)) for c in img_id))
+
+
+if __name__ == '__main__':
+    main()