1//===-- LZMA.cpp ------------------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "lldb/Host/Config.h"
10#include "llvm/ADT/StringRef.h"
11#include "llvm/Support/Error.h"
12
13#if LLDB_ENABLE_LZMA
14#include <lzma.h>
15#endif // LLDB_ENABLE_LZMA
16
17namespace lldb_private {
18
19namespace lzma {
20
21#if !LLDB_ENABLE_LZMA
22bool isAvailable() { return false; }
23llvm::Expected<uint64_t>
24getUncompressedSize(llvm::ArrayRef<uint8_t> InputBuffer) {
25  llvm_unreachable("lzma::getUncompressedSize is unavailable");
26}
27
28llvm::Error uncompress(llvm::ArrayRef<uint8_t> InputBuffer,
29                       llvm::SmallVectorImpl<uint8_t> &Uncompressed) {
30  llvm_unreachable("lzma::uncompress is unavailable");
31}
32
33#else // LLDB_ENABLE_LZMA
34
35bool isAvailable() { return true; }
36
37static const char *convertLZMACodeToString(lzma_ret Code) {
38  switch (Code) {
39  case LZMA_STREAM_END:
40    return "lzma error: LZMA_STREAM_END";
41  case LZMA_NO_CHECK:
42    return "lzma error: LZMA_NO_CHECK";
43  case LZMA_UNSUPPORTED_CHECK:
44    return "lzma error: LZMA_UNSUPPORTED_CHECK";
45  case LZMA_GET_CHECK:
46    return "lzma error: LZMA_GET_CHECK";
47  case LZMA_MEM_ERROR:
48    return "lzma error: LZMA_MEM_ERROR";
49  case LZMA_MEMLIMIT_ERROR:
50    return "lzma error: LZMA_MEMLIMIT_ERROR";
51  case LZMA_FORMAT_ERROR:
52    return "lzma error: LZMA_FORMAT_ERROR";
53  case LZMA_OPTIONS_ERROR:
54    return "lzma error: LZMA_OPTIONS_ERROR";
55  case LZMA_DATA_ERROR:
56    return "lzma error: LZMA_DATA_ERROR";
57  case LZMA_BUF_ERROR:
58    return "lzma error: LZMA_BUF_ERROR";
59  case LZMA_PROG_ERROR:
60    return "lzma error: LZMA_PROG_ERROR";
61  default:
62    llvm_unreachable("unknown or unexpected lzma status code");
63  }
64}
65
66llvm::Expected<uint64_t>
67getUncompressedSize(llvm::ArrayRef<uint8_t> InputBuffer) {
68  lzma_stream_flags opts{};
69  if (InputBuffer.size() < LZMA_STREAM_HEADER_SIZE) {
70    return llvm::createStringError(
71        llvm::inconvertibleErrorCode(),
72        "size of xz-compressed blob (%lu bytes) is smaller than the "
73        "LZMA_STREAM_HEADER_SIZE (%lu bytes)",
74        InputBuffer.size(), LZMA_STREAM_HEADER_SIZE);
75  }
76
77  // Decode xz footer.
78  lzma_ret xzerr = lzma_stream_footer_decode(
79      &opts, InputBuffer.take_back(LZMA_STREAM_HEADER_SIZE).data());
80  if (xzerr != LZMA_OK) {
81    return llvm::createStringError(llvm::inconvertibleErrorCode(),
82                                   "lzma_stream_footer_decode()=%s",
83                                   convertLZMACodeToString(xzerr));
84  }
85  if (InputBuffer.size() < (opts.backward_size + LZMA_STREAM_HEADER_SIZE)) {
86    return llvm::createStringError(
87        llvm::inconvertibleErrorCode(),
88        "xz-compressed buffer size (%lu bytes) too small (required at "
89        "least %lu bytes) ",
90        InputBuffer.size(), (opts.backward_size + LZMA_STREAM_HEADER_SIZE));
91  }
92
93  // Decode xz index.
94  lzma_index *xzindex;
95  uint64_t memlimit(UINT64_MAX);
96  size_t inpos = 0;
97  xzerr = lzma_index_buffer_decode(
98      &xzindex, &memlimit, nullptr,
99      InputBuffer.take_back(LZMA_STREAM_HEADER_SIZE + opts.backward_size)
100          .data(),
101      &inpos, InputBuffer.size());
102  if (xzerr != LZMA_OK) {
103    return llvm::createStringError(llvm::inconvertibleErrorCode(),
104                                   "lzma_index_buffer_decode()=%s",
105                                   convertLZMACodeToString(xzerr));
106  }
107
108  // Get size of uncompressed file to construct an in-memory buffer of the
109  // same size on the calling end (if needed).
110  uint64_t uncompressedSize = lzma_index_uncompressed_size(xzindex);
111
112  // Deallocate xz index as it is no longer needed.
113  lzma_index_end(xzindex, nullptr);
114
115  return uncompressedSize;
116}
117
118llvm::Error uncompress(llvm::ArrayRef<uint8_t> InputBuffer,
119                       llvm::SmallVectorImpl<uint8_t> &Uncompressed) {
120  llvm::Expected<uint64_t> uncompressedSize = getUncompressedSize(InputBuffer);
121
122  if (auto err = uncompressedSize.takeError())
123    return err;
124
125  Uncompressed.resize(*uncompressedSize);
126
127  // Decompress xz buffer to buffer.
128  uint64_t memlimit = UINT64_MAX;
129  size_t inpos = 0;
130  size_t outpos = 0;
131  lzma_ret ret = lzma_stream_buffer_decode(
132      &memlimit, 0, nullptr, InputBuffer.data(), &inpos, InputBuffer.size(),
133      Uncompressed.data(), &outpos, Uncompressed.size());
134  if (ret != LZMA_OK) {
135    return llvm::createStringError(llvm::inconvertibleErrorCode(),
136                                   "lzma_stream_buffer_decode()=%s",
137                                   convertLZMACodeToString(ret));
138  }
139
140  return llvm::Error::success();
141}
142
143#endif // LLDB_ENABLE_LZMA
144
145} // end of namespace lzma
146} // namespace lldb_private
147