1 //
2 // Copyright (C) 2016 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 #include "update_engine/payload_generator/xz.h"
18
19 #include <7zCrc.h>
20 #include <Xz.h>
21 #include <XzEnc.h>
22
23 #include <algorithm>
24
25 #include <base/logging.h>
26
27 namespace {
28
29 bool xz_initialized = false;
30
31 // An ISeqInStream implementation that reads all the data from the passed Blob.
32 struct BlobReaderStream : public ISeqInStream {
BlobReaderStream__anonb8e6353e0111::BlobReaderStream33 explicit BlobReaderStream(const brillo::Blob& data) : data_(data) {
34 Read = &BlobReaderStream::ReadStatic;
35 }
36
ReadStatic__anonb8e6353e0111::BlobReaderStream37 static SRes ReadStatic(void* p, void* buf, size_t* size) {
38 auto* self =
39 static_cast<BlobReaderStream*>(reinterpret_cast<ISeqInStream*>(p));
40 *size = std::min(*size, self->data_.size() - self->pos_);
41 memcpy(buf, self->data_.data() + self->pos_, *size);
42 self->pos_ += *size;
43 return SZ_OK;
44 }
45
46 const brillo::Blob& data_;
47
48 // The current reader position.
49 size_t pos_ = 0;
50 };
51
52 // An ISeqOutStream implementation that writes all the data to the passed Blob.
53 struct BlobWriterStream : public ISeqOutStream {
BlobWriterStream__anonb8e6353e0111::BlobWriterStream54 explicit BlobWriterStream(brillo::Blob* data) : data_(data) {
55 Write = &BlobWriterStream::WriteStatic;
56 }
57
WriteStatic__anonb8e6353e0111::BlobWriterStream58 static size_t WriteStatic(void* p, const void* buf, size_t size) {
59 auto* self =
60 static_cast<BlobWriterStream*>(reinterpret_cast<ISeqOutStream*>(p));
61 const uint8_t* buffer = reinterpret_cast<const uint8_t*>(buf);
62 self->data_->reserve(self->data_->size() + size);
63 self->data_->insert(self->data_->end(), buffer, buffer + size);
64 return size;
65 }
66
67 brillo::Blob* data_;
68 };
69
70 } // namespace
71
72 namespace chromeos_update_engine {
73
XzCompressInit()74 void XzCompressInit() {
75 if (xz_initialized)
76 return;
77 xz_initialized = true;
78 // Although we don't include a CRC32 for the stream, the xz file header has
79 // a CRC32 of the header itself, which required the CRC table to be
80 // initialized.
81 CrcGenerateTable();
82 }
83
XzCompress(const brillo::Blob & in,brillo::Blob * out)84 bool XzCompress(const brillo::Blob& in, brillo::Blob* out) {
85 CHECK(xz_initialized) << "Initialize XzCompress first";
86 out->clear();
87 if (in.empty())
88 return true;
89
90 // Xz compression properties.
91 CXzProps props;
92 XzProps_Init(&props);
93 // No checksum in the xz stream. xz-embedded (used by the decompressor) only
94 // supports CRC32, but we already check the sha-1 of the whole blob during
95 // payload application.
96 props.checkId = XZ_CHECK_NO;
97
98 // LZMA2 compression properties.
99 CLzma2EncProps lzma2Props;
100 props.lzma2Props = &lzma2Props;
101 Lzma2EncProps_Init(&lzma2Props);
102 // LZMA compression "level 6" requires 9 MB of RAM to decompress in the worst
103 // case.
104 lzma2Props.lzmaProps.level = 6;
105 lzma2Props.lzmaProps.numThreads = 1;
106 // The input size data is used to reduce the dictionary size if possible.
107 lzma2Props.lzmaProps.reduceSize = in.size();
108 Lzma2EncProps_Normalize(&lzma2Props);
109
110 BlobWriterStream out_writer(out);
111 BlobReaderStream in_reader(in);
112 SRes res = Xz_Encode(&out_writer, &in_reader, &props, nullptr /* progress */);
113 return res == SZ_OK;
114 }
115
116 } // namespace chromeos_update_engine
117