1#
2# Copyright (C) 2018 The Android Open Source Project
3#
4# Licensed under the Apache License, Version 2.0 (the "License");
5# you may not use this file except in compliance with the License.
6# You may obtain a copy of the License at
7#
8#      http://www.apache.org/licenses/LICENSE-2.0
9#
10# Unless required by applicable law or agreed to in writing, software
11# distributed under the License is distributed on an "AS IS" BASIS,
12# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13# See the License for the specific language governing permissions and
14# limitations under the License.
15#
16
17"""
18Utils for running unittests.
19"""
20
21import os
22import os.path
23import struct
24
25import common
26
27
28def get_testdata_dir():
29  """Returns the testdata dir, in relative to the script dir."""
30  # The script dir is the one we want, which could be different from pwd.
31  current_dir = os.path.dirname(os.path.realpath(__file__))
32  return os.path.join(current_dir, 'testdata')
33
34
35def get_search_path():
36  """Returns the search path that has 'framework/signapk.jar' under."""
37  current_dir = os.path.dirname(os.path.realpath(__file__))
38  for path in (
39      # In relative to 'build/make/tools/releasetools' in the Android source.
40      ['..'] * 4 + ['out', 'host', 'linux-x86'],
41      # Or running the script unpacked from otatools.zip.
42      ['..']):
43    full_path = os.path.realpath(os.path.join(current_dir, *path))
44    signapk_path = os.path.realpath(
45        os.path.join(full_path, 'framework', 'signapk.jar'))
46    if os.path.exists(signapk_path):
47      return full_path
48  return None
49
50
51def construct_sparse_image(chunks):
52  """Returns a sparse image file constructed from the given chunks.
53
54  From system/core/libsparse/sparse_format.h.
55  typedef struct sparse_header {
56    __le32 magic;  // 0xed26ff3a
57    __le16 major_version;  // (0x1) - reject images with higher major versions
58    __le16 minor_version;  // (0x0) - allow images with higer minor versions
59    __le16 file_hdr_sz;  // 28 bytes for first revision of the file format
60    __le16 chunk_hdr_sz;  // 12 bytes for first revision of the file format
61    __le32 blk_sz;  // block size in bytes, must be a multiple of 4 (4096)
62    __le32 total_blks;  // total blocks in the non-sparse output image
63    __le32 total_chunks;  // total chunks in the sparse input image
64    __le32 image_checksum;  // CRC32 checksum of the original data, counting
65                            // "don't care" as 0. Standard 802.3 polynomial,
66                            // use a Public Domain table implementation
67  } sparse_header_t;
68
69  typedef struct chunk_header {
70    __le16 chunk_type;  // 0xCAC1 -> raw; 0xCAC2 -> fill;
71                        // 0xCAC3 -> don't care
72    __le16 reserved1;
73    __le32 chunk_sz;  // in blocks in output image
74    __le32 total_sz;  // in bytes of chunk input file including chunk header
75                      // and data
76  } chunk_header_t;
77
78  Args:
79    chunks: A list of chunks to be written. Each entry should be a tuple of
80        (chunk_type, block_number).
81
82  Returns:
83    Filename of the created sparse image.
84  """
85  SPARSE_HEADER_MAGIC = 0xED26FF3A
86  SPARSE_HEADER_FORMAT = "<I4H4I"
87  CHUNK_HEADER_FORMAT = "<2H2I"
88
89  sparse_image = common.MakeTempFile(prefix='sparse-', suffix='.img')
90  with open(sparse_image, 'wb') as fp:
91    fp.write(struct.pack(
92        SPARSE_HEADER_FORMAT, SPARSE_HEADER_MAGIC, 1, 0, 28, 12, 4096,
93        sum(chunk[1] for chunk in chunks),
94        len(chunks), 0))
95
96    for chunk in chunks:
97      data_size = 0
98      if chunk[0] == 0xCAC1:
99        data_size = 4096 * chunk[1]
100      elif chunk[0] == 0xCAC2:
101        data_size = 4
102      elif chunk[0] == 0xCAC3:
103        pass
104      else:
105        assert False, "Unsupported chunk type: {}".format(chunk[0])
106
107      fp.write(struct.pack(
108          CHUNK_HEADER_FORMAT, chunk[0], 0, chunk[1], data_size + 12))
109      if data_size != 0:
110        fp.write(os.urandom(data_size))
111
112  return sparse_image
113