1 //===-- LZMA.cpp ----------------------------------------------------------===//
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 
17 namespace lldb_private {
18 
19 namespace lzma {
20 
21 #if !LLDB_ENABLE_LZMA
22 bool isAvailable() { return false; }
23 llvm::Expected<uint64_t>
24 getUncompressedSize(llvm::ArrayRef<uint8_t> InputBuffer) {
25   llvm_unreachable("lzma::getUncompressedSize is unavailable");
26 }
27 
28 llvm::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 
35 bool isAvailable() { return true; }
36 
37 static 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 
66 llvm::Expected<uint64_t>
67 getUncompressedSize(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 
118 llvm::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