build_image.py revision fc44a515d46e6f4d5eaa0d32659b1cf3b9492305 
1#!/usr/bin/env python
2#
3# Copyright (C) 2011 The Android Open Source Project
4#
5# Licensed under the Apache License, Version 2.0 (the "License");
6# you may not use this file except in compliance with the License.
7# You may obtain a copy of the License at
8#
9#      http://www.apache.org/licenses/LICENSE-2.0
10#
11# Unless required by applicable law or agreed to in writing, software
12# distributed under the License is distributed on an "AS IS" BASIS,
13# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14# See the License for the specific language governing permissions and
15# limitations under the License.
16
17"""
18Build image output_image_file from input_directory and properties_file.
19
20Usage:  build_image input_directory properties_file output_image_file
21
22"""
23import os
24import os.path
25import subprocess
26import sys
27import commands
28import shutil
29import tempfile
30
31FIXED_SALT = "aee087a5be3b982978c923f566a94613496b417f2af592639bc80d141e34dfe7"
32
33def RunCommand(cmd):
34  """ Echo and run the given command
35
36  Args:
37    cmd: the command represented as a list of strings.
38  Returns:
39    The exit code.
40  """
41  print "Running: ", " ".join(cmd)
42  p = subprocess.Popen(cmd)
43  p.communicate()
44  return p.returncode
45
46def GetVerityTreeSize(partition_size):
47  cmd = "build_verity_tree -s %d"
48  cmd %= partition_size
49  status, output = commands.getstatusoutput(cmd)
50  if status:
51    print output
52    return False, 0
53  return True, int(output)
54
55def GetVerityMetadataSize(partition_size):
56  cmd = "system/extras/verity/build_verity_metadata.py -s %d"
57  cmd %= partition_size
58  status, output = commands.getstatusoutput(cmd)
59  if status:
60    print output
61    return False, 0
62  return True, int(output)
63
64def AdjustPartitionSizeForVerity(partition_size):
65  """Modifies the provided partition size to account for the verity metadata.
66
67  This information is used to size the created image appropriately.
68  Args:
69    partition_size: the size of the partition to be verified.
70  Returns:
71    The size of the partition adjusted for verity metadata.
72  """
73  success, verity_tree_size = GetVerityTreeSize(partition_size)
74  if not success:
75    return 0;
76  success, verity_metadata_size = GetVerityMetadataSize(partition_size)
77  if not success:
78    return 0
79  return partition_size - verity_tree_size - verity_metadata_size
80
81def BuildVerityTree(sparse_image_path, verity_image_path, prop_dict):
82  cmd = ("build_verity_tree -A %s %s %s" % (FIXED_SALT, sparse_image_path, verity_image_path))
83  print cmd
84  status, output = commands.getstatusoutput(cmd)
85  if status:
86    print "Could not build verity tree! Error: %s" % output
87    return False
88  root, salt = output.split()
89  prop_dict["verity_root_hash"] = root
90  prop_dict["verity_salt"] = salt
91  return True
92
93def BuildVerityMetadata(image_size, verity_metadata_path, root_hash, salt,
94                        block_device, signer_path, key):
95  cmd = ("system/extras/verity/build_verity_metadata.py %s %s %s %s %s %s %s" %
96              (image_size,
97              verity_metadata_path,
98              root_hash,
99              salt,
100              block_device,
101              signer_path,
102              key))
103  print cmd
104  status, output = commands.getstatusoutput(cmd)
105  if status:
106    print "Could not build verity metadata! Error: %s" % output
107    return False
108  return True
109
110def Append2Simg(sparse_image_path, unsparse_image_path, error_message):
111  """Appends the unsparse image to the given sparse image.
112
113  Args:
114    sparse_image_path: the path to the (sparse) image
115    unsparse_image_path: the path to the (unsparse) image
116  Returns:
117    True on success, False on failure.
118  """
119  cmd = "append2simg %s %s"
120  cmd %= (sparse_image_path, unsparse_image_path)
121  print cmd
122  status, output = commands.getstatusoutput(cmd)
123  if status:
124    print "%s: %s" % (error_message, output)
125    return False
126  return True
127
128def BuildVerifiedImage(data_image_path, verity_image_path, verity_metadata_path):
129  if not Append2Simg(data_image_path, verity_metadata_path, "Could not append verity metadata!"):
130    return False
131  if not Append2Simg(data_image_path, verity_image_path, "Could not append verity tree!"):
132    return False
133  return True
134
135def UnsparseImage(sparse_image_path, replace=True):
136  img_dir = os.path.dirname(sparse_image_path)
137  unsparse_image_path = "unsparse_" + os.path.basename(sparse_image_path)
138  unsparse_image_path = os.path.join(img_dir, unsparse_image_path)
139  if os.path.exists(unsparse_image_path):
140    if replace:
141      os.unlink(unsparse_image_path)
142    else:
143      return True, unsparse_image_path
144  inflate_command = ["simg2img", sparse_image_path, unsparse_image_path]
145  exit_code = RunCommand(inflate_command)
146  if exit_code != 0:
147    os.remove(unsparse_image_path)
148    return False, None
149  return True, unsparse_image_path
150
151def MakeVerityEnabledImage(out_file, prop_dict):
152  """Creates an image that is verifiable using dm-verity.
153
154  Args:
155    out_file: the location to write the verifiable image at
156    prop_dict: a dictionary of properties required for image creation and verification
157  Returns:
158    True on success, False otherwise.
159  """
160  # get properties
161  image_size = prop_dict["partition_size"]
162  block_dev = prop_dict["verity_block_device"]
163  signer_key = prop_dict["verity_key"]
164  signer_path = prop_dict["verity_signer_cmd"]
165
166  # make a tempdir
167  tempdir_name = tempfile.mkdtemp(suffix="_verity_images")
168
169  # get partial image paths
170  verity_image_path = os.path.join(tempdir_name, "verity.img")
171  verity_metadata_path = os.path.join(tempdir_name, "verity_metadata.img")
172
173  # build the verity tree and get the root hash and salt
174  if not BuildVerityTree(out_file, verity_image_path, prop_dict):
175    shutil.rmtree(tempdir_name, ignore_errors=True)
176    return False
177
178  # build the metadata blocks
179  root_hash = prop_dict["verity_root_hash"]
180  salt = prop_dict["verity_salt"]
181  if not BuildVerityMetadata(image_size,
182                              verity_metadata_path,
183                              root_hash,
184                              salt,
185                              block_dev,
186                              signer_path,
187                              signer_key):
188    shutil.rmtree(tempdir_name, ignore_errors=True)
189    return False
190
191  # build the full verified image
192  if not BuildVerifiedImage(out_file,
193                            verity_image_path,
194                            verity_metadata_path):
195    shutil.rmtree(tempdir_name, ignore_errors=True)
196    return False
197
198  shutil.rmtree(tempdir_name, ignore_errors=True)
199  return True
200
201def BuildImage(in_dir, prop_dict, out_file,
202               fs_config=None,
203               fc_config=None,
204               block_list=None):
205  """Build an image to out_file from in_dir with property prop_dict.
206
207  Args:
208    in_dir: path of input directory.
209    prop_dict: property dictionary.
210    out_file: path of the output image file.
211    fs_config: path to the fs_config file (typically
212      META/filesystem_config.txt).  If None then the configuration in
213      the local client will be used.
214    fc_config: path to the SELinux file_contexts file.  If None then
215      the value from prop_dict['selinux_fc'] will be used.
216
217  Returns:
218    True iff the image is built successfully.
219  """
220  build_command = []
221  fs_type = prop_dict.get("fs_type", "")
222  run_fsck = False
223
224  is_verity_partition = "verity_block_device" in prop_dict
225  verity_supported = prop_dict.get("verity") == "true"
226  # adjust the partition size to make room for the hashes if this is to be verified
227  if verity_supported and is_verity_partition:
228    partition_size = int(prop_dict.get("partition_size"))
229    adjusted_size = AdjustPartitionSizeForVerity(partition_size)
230    if not adjusted_size:
231      return False
232    prop_dict["partition_size"] = str(adjusted_size)
233    prop_dict["original_partition_size"] = str(partition_size)
234
235  if fs_type.startswith("ext"):
236    build_command = ["mkuserimg.sh"]
237    if "extfs_sparse_flag" in prop_dict:
238      build_command.append(prop_dict["extfs_sparse_flag"])
239      run_fsck = True
240    build_command.extend([in_dir, out_file, fs_type,
241                          prop_dict["mount_point"]])
242    build_command.append(prop_dict["partition_size"])
243    if "timestamp" in prop_dict:
244      build_command.extend(["-T", str(prop_dict["timestamp"])])
245    if fs_config is not None:
246      build_command.extend(["-C", fs_config])
247    if block_list is not None:
248      build_command.extend(["-B", block_list])
249    if fc_config is not None:
250      build_command.append(fc_config)
251    elif "selinux_fc" in prop_dict:
252      build_command.append(prop_dict["selinux_fc"])
253  elif fs_type.startswith("f2fs"):
254    build_command = ["mkf2fsuserimg.sh"]
255    build_command.extend([out_file, prop_dict["partition_size"]])
256  else:
257    build_command = ["mkyaffs2image", "-f"]
258    if prop_dict.get("mkyaffs2_extra_flags", None):
259      build_command.extend(prop_dict["mkyaffs2_extra_flags"].split())
260    build_command.append(in_dir)
261    build_command.append(out_file)
262    if "selinux_fc" in prop_dict:
263      build_command.append(prop_dict["selinux_fc"])
264      build_command.append(prop_dict["mount_point"])
265
266  exit_code = RunCommand(build_command)
267  if exit_code != 0:
268    return False
269
270  # create the verified image if this is to be verified
271  if verity_supported and is_verity_partition:
272    if not MakeVerityEnabledImage(out_file, prop_dict):
273      return False
274
275  if run_fsck and prop_dict.get("skip_fsck") != "true":
276    success, unsparse_image = UnsparseImage(out_file, replace=False)
277    if not success:
278      return False
279
280    # Run e2fsck on the inflated image file
281    e2fsck_command = ["e2fsck", "-f", "-n", unsparse_image]
282    exit_code = RunCommand(e2fsck_command)
283
284    os.remove(unsparse_image)
285
286  return exit_code == 0
287
288
289def ImagePropFromGlobalDict(glob_dict, mount_point):
290  """Build an image property dictionary from the global dictionary.
291
292  Args:
293    glob_dict: the global dictionary from the build system.
294    mount_point: such as "system", "data" etc.
295  """
296  d = {}
297  if "build.prop" in glob_dict:
298    bp = glob_dict["build.prop"]
299    if "ro.build.date.utc" in bp:
300      d["timestamp"] = bp["ro.build.date.utc"]
301
302  def copy_prop(src_p, dest_p):
303    if src_p in glob_dict:
304      d[dest_p] = str(glob_dict[src_p])
305
306  common_props = (
307      "extfs_sparse_flag",
308      "mkyaffs2_extra_flags",
309      "selinux_fc",
310      "skip_fsck",
311      "verity",
312      "verity_key",
313      "verity_signer_cmd"
314      )
315  for p in common_props:
316    copy_prop(p, p)
317
318  d["mount_point"] = mount_point
319  if mount_point == "system":
320    copy_prop("fs_type", "fs_type")
321    copy_prop("system_size", "partition_size")
322    copy_prop("system_verity_block_device", "verity_block_device")
323  elif mount_point == "data":
324    # Copy the generic fs type first, override with specific one if available.
325    copy_prop("fs_type", "fs_type")
326    copy_prop("userdata_fs_type", "fs_type")
327    copy_prop("userdata_size", "partition_size")
328  elif mount_point == "cache":
329    copy_prop("cache_fs_type", "fs_type")
330    copy_prop("cache_size", "partition_size")
331  elif mount_point == "vendor":
332    copy_prop("vendor_fs_type", "fs_type")
333    copy_prop("vendor_size", "partition_size")
334    copy_prop("vendor_verity_block_device", "verity_block_device")
335  elif mount_point == "oem":
336    copy_prop("fs_type", "fs_type")
337    copy_prop("oem_size", "partition_size")
338
339  return d
340
341
342def LoadGlobalDict(filename):
343  """Load "name=value" pairs from filename"""
344  d = {}
345  f = open(filename)
346  for line in f:
347    line = line.strip()
348    if not line or line.startswith("#"):
349      continue
350    k, v = line.split("=", 1)
351    d[k] = v
352  f.close()
353  return d
354
355
356def main(argv):
357  if len(argv) != 3:
358    print __doc__
359    sys.exit(1)
360
361  in_dir = argv[0]
362  glob_dict_file = argv[1]
363  out_file = argv[2]
364
365  glob_dict = LoadGlobalDict(glob_dict_file)
366  image_filename = os.path.basename(out_file)
367  mount_point = ""
368  if image_filename == "system.img":
369    mount_point = "system"
370  elif image_filename == "userdata.img":
371    mount_point = "data"
372  elif image_filename == "cache.img":
373    mount_point = "cache"
374  elif image_filename == "vendor.img":
375    mount_point = "vendor"
376  elif image_filename == "oem.img":
377    mount_point = "oem"
378  else:
379    print >> sys.stderr, "error: unknown image file name ", image_filename
380    exit(1)
381
382  image_properties = ImagePropFromGlobalDict(glob_dict, mount_point)
383  if not BuildImage(in_dir, image_properties, out_file):
384    print >> sys.stderr, "error: failed to build %s from %s" % (out_file, in_dir)
385    exit(1)
386
387
388if __name__ == '__main__':
389  main(sys.argv[1:])
390