From 7bfac8dc1bd69f23d2bf564e604e181292d52263 Mon Sep 17 00:00:00 2001
From: Cyrille Bagard <nocbos@gmail.com>
Date: Sun, 7 Jul 2019 23:53:15 +0200
Subject: Updated the code for the unpackbootimg tool.

---
 python/unpackbootimg.py | 184 +++++++++++++++++++++++++++++++++++-------------
 1 file changed, 134 insertions(+), 50 deletions(-)

diff --git a/python/unpackbootimg.py b/python/unpackbootimg.py
index addc408..d21e469 100644
--- a/python/unpackbootimg.py
+++ b/python/unpackbootimg.py
@@ -1,11 +1,116 @@
-#!/usr/bin/python3
-# -*- coding: utf-8 -*-
 
 import argparse
-import sys
 import pychrysalide
 from pychrysalide.analysis.contents import FileContent
-from pychrysalide.format.bootimg import BootimgFormat
+from pychrysalide.format.bootimg import BootImgFormat
+import struct
+
+
+def _value_to_string(val):
+    """Convert a field into a string."""
+
+    encodings = [ 'ascii', 'utf-8', 'utf-16' ]
+
+    desc = None
+
+    for enc in encodings:
+
+        try:
+            desc = '"%s"' % val.decode(enc)
+        except:
+            desc = None
+
+        if desc:
+            break
+
+    if not(desc):
+
+        count = val.find(b'\x00')
+
+        if count == -1:
+            count = len(val)
+
+        desc = '%u byte(s)' % count
+
+    return desc
+
+
+def _value_to_size(val):
+    """Convert a field into a human-readable size."""
+
+    unit = 0
+
+    units = [ '', 'Kb', 'Mb', 'Gb' ]
+
+    for i in range(3):
+        if val > 1024:
+            val /= 1024
+            unit += 1
+
+    if val == int(val):
+        return '%u%s' % (val, units[unit])
+    else:
+        return '%.1f%s' % (val, units[unit])
+
+
+def _value_to_id(val):
+    """Convert a field into an identifier."""
+
+    values = struct.unpack('<IIIIIIII', val)
+
+    return ' '.join(['0x%08x' % v for v in values])
+
+
+def show_info(fmt):
+    """Display all available information about a given Boot image."""
+
+    hdr = fmt.header
+
+    items = [
+
+        [ 'magic', _value_to_string(hdr.magic) ],
+        [ 'kernel_size', _value_to_size(hdr.kernel_size) ],
+        [ 'kernel_addr', hex(hdr.kernel_addr) ],
+
+        [ 'ramdisk_size', _value_to_size(hdr.ramdisk_size) ],
+        [ 'ramdisk_addr', hex(hdr.ramdisk_addr) ],
+
+        [ 'second_size', _value_to_size(hdr.second_size) ],
+        [ 'second_addr', hex(hdr.second_addr) ],
+
+        [ 'tags_addr', hex(hdr.tags_addr) ],
+        [ 'page_size', _value_to_size(hdr.page_size) ],
+        [ 'header_version', hdr.header_version ],
+        [ 'os_version', hex(hdr.os_version) ],
+        [ 'name', _value_to_string(hdr.name) ],
+        [ 'cmdline', _value_to_string(hdr.cmdline) ],
+        [ 'id', _value_to_id(hdr.id) ],
+        [ 'extra_cmdline', _value_to_string(hdr.extra_cmdline) ],
+
+        [ 'recovery_dtbo_size', _value_to_size(hdr.recovery_dtbo_size) ],
+        [ 'recovery_dtbo_offset', hex(hdr.recovery_dtbo_offset) ],
+        [ 'header_size', _value_to_size(hdr.header_size) ],
+
+    ]
+
+    length = 0
+
+    for key, _ in items:
+        if (len(key) + 1) > length:
+            length = len(key) + 1
+
+    line = '  {:<%u} {:}' % length
+
+    title = ' Boot image header'
+
+    print()
+    print(title)
+    print('=' * len(title))
+
+    for key, val in items:
+        print(line.format(key + ':', val))
+
+    print()
 
 
 if __name__ == '__main__':
@@ -13,67 +118,46 @@ if __name__ == '__main__':
 
     parser = argparse.ArgumentParser()
 
-    parser.add_argument('bootimg', help='path to the Android boot imgage to process')
+    parser.add_argument('-i', '--info',    help='display information about the boot image', action='store_true')
+    parser.add_argument('-k', '--kernel',  help='dump the kernel embedded in the boot image', action='store_true')
+    parser.add_argument('-r', '--ramdisk', help='dump the ramdisk embedded in the boot image', action='store_true')
+    parser.add_argument('filename',        help='path to the Android boot image', metavar='boot.img')
 
     args = parser.parse_args()
 
-    cnt = FileContent(args.bootimg)
+    cnt = FileContent(args.filename)
 
     if cnt is None:
         sys.exit('No content to load!')
 
-    fmt = BootimgFormat(cnt)
-
-    if fmt is None:
-        sys.exit('Failed to load the boot image!')
-
-    oattribs = [
-        'magic',
-        'kernel_size',
-        'kernel_addr',
-        'ramdisk_size',
-        'ramdisk_addr',
-        'second_size',
-        'second_addr',
-        'tags_addr',
-        'page_size',
-        'header_version',
-        'os_version',
-        'name',
-        'cmdline',
-        'extra_cmdline'
-    ]
+    fmt = BootImgFormat(cnt)
+
+    status = fmt.analyze()
+
+    if not(status):
+        sys.exit('Bad boot image!')
 
-    maxlen = 0
+    if args.info:
+        show_info(fmt)
 
-    for a in oattribs:
-        if len(a) > maxlen:
-            maxlen = len(a)
+    if args.kernel:
 
-    name = ' {0:<%u}' % (maxlen + 1)
+        if fmt.kernel:
 
-    header = fmt.get_header()
+            with open('kernel.bin', 'wb') as fd:
+                fd.write(fmt.kernel.data)
 
-    for a in oattribs:
+        else:
 
-        v = getattr(header, a)
+            print('No kernel to extract!')
 
-        value = '0x%x' % v if type(v) == int else v
+        if args.ramdisk:
 
-        print(name.format(a + ':'), value)
+            if fmt.ramdisk:
 
-        with open(args.bootimg + '-' + a, 'w') as out:
-            out.write(value)
-            out.write('\n')
+                with open('ramdisk.bin', 'wb') as fd:
+                    fd.write(fmt.ramdisk.data)
 
-    contents = {
-        'kernel':        fmt.get_kernel(),
-        'ramdisk':       fmt.get_ramdisk(),
-        'second_stage':  fmt.get_second_stage(),
-        'recovery_dtbo': fmt.get_recovery_dtbo()
-    }
+        else:
 
-    for k, v in contents.items():
-        if v:
-            with open(args.bootimg + '-' + k, 'wb') as out:
-                out.write(v.data)
+            print('No ramdisk to extract!')
-- 
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