1 /*- 2 * Copyright 2003,2004 Colin Percival 3 * All rights reserved 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted providing that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 16 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 18 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 22 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 23 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 24 * POSSIBILITY OF SUCH DAMAGE. 25 * 26 * Changelog: 27 * 2009-03-31 - Change to use Streams. Move CRC code to crc.{h,cc} 28 * --Stephen Adams <sra (at) chromium.org> 29 * 2013-04-10 - Add wrapper method to apply a patch to files directly. 30 * --Joshua Pawlicki <waffles (at) chromium.org> 31 */ 32 33 // Copyright (c) 2009 The Chromium Authors. All rights reserved. 34 // Use of this source code is governed by a BSD-style license that can be 35 // found in the LICENSE file. 36 37 #include "courgette/third_party/bsdiff.h" 38 39 #include "base/files/memory_mapped_file.h" 40 #include "courgette/crc.h" 41 #include "courgette/streams.h" 42 43 namespace courgette { 44 45 BSDiffStatus MBS_ReadHeader(SourceStream* stream, MBSPatchHeader* header) { 46 if (!stream->Read(header->tag, sizeof(header->tag))) return READ_ERROR; 47 if (!stream->ReadVarint32(&header->slen)) return READ_ERROR; 48 if (!stream->ReadVarint32(&header->scrc32)) return READ_ERROR; 49 if (!stream->ReadVarint32(&header->dlen)) return READ_ERROR; 50 51 // The string will have a NUL terminator that we don't use, hence '-1'. 52 COMPILE_ASSERT(sizeof(MBS_PATCH_HEADER_TAG) - 1 == sizeof(header->tag), 53 MBS_PATCH_HEADER_TAG_must_match_header_field_size); 54 if (memcmp(header->tag, MBS_PATCH_HEADER_TAG, 8) != 0) 55 return UNEXPECTED_ERROR; 56 57 return OK; 58 } 59 60 BSDiffStatus MBS_ApplyPatch(const MBSPatchHeader *header, 61 SourceStream* patch_stream, 62 const uint8* old_start, size_t old_size, 63 SinkStream* new_stream) { 64 const uint8* old_end = old_start + old_size; 65 66 SourceStreamSet patch_streams; 67 if (!patch_streams.Init(patch_stream)) 68 return READ_ERROR; 69 70 SourceStream* control_stream_copy_counts = patch_streams.stream(0); 71 SourceStream* control_stream_extra_counts = patch_streams.stream(1); 72 SourceStream* control_stream_seeks = patch_streams.stream(2); 73 SourceStream* diff_skips = patch_streams.stream(3); 74 SourceStream* diff_bytes = patch_streams.stream(4); 75 SourceStream* extra_bytes = patch_streams.stream(5); 76 77 const uint8* extra_start = extra_bytes->Buffer(); 78 const uint8* extra_end = extra_start + extra_bytes->Remaining(); 79 const uint8* extra_position = extra_start; 80 81 const uint8* old_position = old_start; 82 83 if (header->dlen && !new_stream->Reserve(header->dlen)) 84 return MEM_ERROR; 85 86 uint32 pending_diff_zeros = 0; 87 if (!diff_skips->ReadVarint32(&pending_diff_zeros)) 88 return UNEXPECTED_ERROR; 89 90 while (!control_stream_copy_counts->Empty()) { 91 uint32 copy_count, extra_count; 92 int32 seek_adjustment; 93 if (!control_stream_copy_counts->ReadVarint32(©_count)) 94 return UNEXPECTED_ERROR; 95 if (!control_stream_extra_counts->ReadVarint32(&extra_count)) 96 return UNEXPECTED_ERROR; 97 if (!control_stream_seeks->ReadVarint32Signed(&seek_adjustment)) 98 return UNEXPECTED_ERROR; 99 100 #ifdef DEBUG_bsmedberg 101 printf("Applying block: copy: %-8u extra: %-8u seek: %+i\n", 102 copy_count, extra_count, seek_adjustment); 103 #endif 104 // Byte-wise arithmetically add bytes from old file to bytes from the diff 105 // block. 106 if (copy_count > static_cast<size_t>(old_end - old_position)) 107 return UNEXPECTED_ERROR; 108 109 // Add together bytes from the 'old' file and the 'diff' stream. 110 for (size_t i = 0; i < copy_count; ++i) { 111 uint8 diff_byte = 0; 112 if (pending_diff_zeros) { 113 --pending_diff_zeros; 114 } else { 115 if (!diff_skips->ReadVarint32(&pending_diff_zeros)) 116 return UNEXPECTED_ERROR; 117 if (!diff_bytes->Read(&diff_byte, 1)) 118 return UNEXPECTED_ERROR; 119 } 120 uint8 byte = old_position[i] + diff_byte; 121 if (!new_stream->Write(&byte, 1)) 122 return MEM_ERROR; 123 } 124 old_position += copy_count; 125 126 // Copy bytes from the extra block. 127 if (extra_count > static_cast<size_t>(extra_end - extra_position)) 128 return UNEXPECTED_ERROR; 129 130 if (!new_stream->Write(extra_position, extra_count)) 131 return MEM_ERROR; 132 133 extra_position += extra_count; 134 135 // "seek" forwards (or backwards) in oldfile. 136 if (old_position + seek_adjustment < old_start || 137 old_position + seek_adjustment > old_end) 138 return UNEXPECTED_ERROR; 139 140 old_position += seek_adjustment; 141 } 142 143 if (!control_stream_copy_counts->Empty() || 144 !control_stream_extra_counts->Empty() || 145 !control_stream_seeks->Empty() || 146 !diff_skips->Empty() || 147 !diff_bytes->Empty() || 148 !extra_bytes->Empty()) 149 return UNEXPECTED_ERROR; 150 151 return OK; 152 } 153 154 BSDiffStatus ApplyBinaryPatch(SourceStream* old_stream, 155 SourceStream* patch_stream, 156 SinkStream* new_stream) { 157 MBSPatchHeader header; 158 BSDiffStatus ret = MBS_ReadHeader(patch_stream, &header); 159 if (ret != OK) return ret; 160 161 const uint8* old_start = old_stream->Buffer(); 162 size_t old_size = old_stream->Remaining(); 163 164 if (old_size != header.slen) return UNEXPECTED_ERROR; 165 166 if (CalculateCrc(old_start, old_size) != header.scrc32) 167 return CRC_ERROR; 168 169 MBS_ApplyPatch(&header, patch_stream, old_start, old_size, new_stream); 170 171 return OK; 172 } 173 174 BSDiffStatus ApplyBinaryPatch(const base::FilePath& old_file_path, 175 const base::FilePath& patch_file_path, 176 const base::FilePath& new_file_path) { 177 // Set up the old stream. 178 base::MemoryMappedFile old_file; 179 if (!old_file.Initialize(old_file_path)) { 180 return READ_ERROR; 181 } 182 SourceStream old_file_stream; 183 old_file_stream.Init(old_file.data(), old_file.length()); 184 185 // Set up the patch stream. 186 base::MemoryMappedFile patch_file; 187 if (!patch_file.Initialize(patch_file_path)) { 188 return READ_ERROR; 189 } 190 SourceStream patch_file_stream; 191 patch_file_stream.Init(patch_file.data(), patch_file.length()); 192 193 // Set up the new stream and apply the patch. 194 SinkStream new_sink_stream; 195 BSDiffStatus status = ApplyBinaryPatch(&old_file_stream, 196 &patch_file_stream, 197 &new_sink_stream); 198 if (status != OK) { 199 return status; 200 } 201 202 // Write the stream to disk. 203 int written = base::WriteFile( 204 new_file_path, 205 reinterpret_cast<const char*>(new_sink_stream.Buffer()), 206 static_cast<int>(new_sink_stream.Length())); 207 if (written != static_cast<int>(new_sink_stream.Length())) 208 return WRITE_ERROR; 209 return OK; 210 } 211 212 } // namespace 213
