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#
# Copyright (C) 2018 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.
#
"""
Utils for running unittests.
"""
import os
import os.path
import struct
import common
def get_testdata_dir():
"""Returns the testdata dir, in relative to the script dir."""
# The script dir is the one we want, which could be different from pwd.
current_dir = os.path.dirname(os.path.realpath(__file__))
return os.path.join(current_dir, 'testdata')
def construct_sparse_image(chunks):
"""Returns a sparse image file constructed from the given chunks.
From system/core/libsparse/sparse_format.h.
typedef struct sparse_header {
__le32 magic; // 0xed26ff3a
__le16 major_version; // (0x1) - reject images with higher major versions
__le16 minor_version; // (0x0) - allow images with higer minor versions
__le16 file_hdr_sz; // 28 bytes for first revision of the file format
__le16 chunk_hdr_sz; // 12 bytes for first revision of the file format
__le32 blk_sz; // block size in bytes, must be a multiple of 4 (4096)
__le32 total_blks; // total blocks in the non-sparse output image
__le32 total_chunks; // total chunks in the sparse input image
__le32 image_checksum; // CRC32 checksum of the original data, counting
// "don't care" as 0. Standard 802.3 polynomial,
// use a Public Domain table implementation
} sparse_header_t;
typedef struct chunk_header {
__le16 chunk_type; // 0xCAC1 -> raw; 0xCAC2 -> fill;
// 0xCAC3 -> don't care
__le16 reserved1;
__le32 chunk_sz; // in blocks in output image
__le32 total_sz; // in bytes of chunk input file including chunk header
// and data
} chunk_header_t;
Args:
chunks: A list of chunks to be written. Each entry should be a tuple of
(chunk_type, block_number).
Returns:
Filename of the created sparse image.
"""
SPARSE_HEADER_MAGIC = 0xED26FF3A
SPARSE_HEADER_FORMAT = "<I4H4I"
CHUNK_HEADER_FORMAT = "<2H2I"
sparse_image = common.MakeTempFile(prefix='sparse-', suffix='.img')
with open(sparse_image, 'wb') as fp:
fp.write(struct.pack(
SPARSE_HEADER_FORMAT, SPARSE_HEADER_MAGIC, 1, 0, 28, 12, 4096,
sum(chunk[1] for chunk in chunks),
len(chunks), 0))
for chunk in chunks:
data_size = 0
if chunk[0] == 0xCAC1:
data_size = 4096 * chunk[1]
elif chunk[0] == 0xCAC2:
data_size = 4
elif chunk[0] == 0xCAC3:
pass
else:
assert False, "Unsupported chunk type: {}".format(chunk[0])
fp.write(struct.pack(
CHUNK_HEADER_FORMAT, chunk[0], 0, chunk[1], data_size + 12))
if data_size != 0:
fp.write(os.urandom(data_size))
return sparse_image