/*-
* Copyright 2003,2004 Colin Percival
* All rights reserved
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted providing that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Changelog:
* 2009-03-31 - Change to use Streams. Move CRC code to crc.{h,cc}
* --Stephen Adams <sra@chromium.org>
* 2013-04-10 - Add wrapper method to apply a patch to files directly.
* --Joshua Pawlicki <waffles@chromium.org>
*/
// Copyright (c) 2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "courgette/third_party/bsdiff.h"
#include "base/files/memory_mapped_file.h"
#include "courgette/crc.h"
#include "courgette/streams.h"
namespace courgette {
BSDiffStatus MBS_ReadHeader(SourceStream* stream, MBSPatchHeader* header) {
if (!stream->Read(header->tag, sizeof(header->tag))) return READ_ERROR;
if (!stream->ReadVarint32(&header->slen)) return READ_ERROR;
if (!stream->ReadVarint32(&header->scrc32)) return READ_ERROR;
if (!stream->ReadVarint32(&header->dlen)) return READ_ERROR;
// The string will have a NUL terminator that we don't use, hence '-1'.
COMPILE_ASSERT(sizeof(MBS_PATCH_HEADER_TAG) - 1 == sizeof(header->tag),
MBS_PATCH_HEADER_TAG_must_match_header_field_size);
if (memcmp(header->tag, MBS_PATCH_HEADER_TAG, 8) != 0)
return UNEXPECTED_ERROR;
return OK;
}
BSDiffStatus MBS_ApplyPatch(const MBSPatchHeader *header,
SourceStream* patch_stream,
const uint8* old_start, size_t old_size,
SinkStream* new_stream) {
const uint8* old_end = old_start + old_size;
SourceStreamSet patch_streams;
if (!patch_streams.Init(patch_stream))
return READ_ERROR;
SourceStream* control_stream_copy_counts = patch_streams.stream(0);
SourceStream* control_stream_extra_counts = patch_streams.stream(1);
SourceStream* control_stream_seeks = patch_streams.stream(2);
SourceStream* diff_skips = patch_streams.stream(3);
SourceStream* diff_bytes = patch_streams.stream(4);
SourceStream* extra_bytes = patch_streams.stream(5);
const uint8* extra_start = extra_bytes->Buffer();
const uint8* extra_end = extra_start + extra_bytes->Remaining();
const uint8* extra_position = extra_start;
const uint8* old_position = old_start;
if (header->dlen && !new_stream->Reserve(header->dlen))
return MEM_ERROR;
uint32 pending_diff_zeros = 0;
if (!diff_skips->ReadVarint32(&pending_diff_zeros))
return UNEXPECTED_ERROR;
while (!control_stream_copy_counts->Empty()) {
uint32 copy_count, extra_count;
int32 seek_adjustment;
if (!control_stream_copy_counts->ReadVarint32(©_count))
return UNEXPECTED_ERROR;
if (!control_stream_extra_counts->ReadVarint32(&extra_count))
return UNEXPECTED_ERROR;
if (!control_stream_seeks->ReadVarint32Signed(&seek_adjustment))
return UNEXPECTED_ERROR;
#ifdef DEBUG_bsmedberg
printf("Applying block: copy: %-8u extra: %-8u seek: %+i\n",
copy_count, extra_count, seek_adjustment);
#endif
// Byte-wise arithmetically add bytes from old file to bytes from the diff
// block.
if (copy_count > static_cast<size_t>(old_end - old_position))
return UNEXPECTED_ERROR;
// Add together bytes from the 'old' file and the 'diff' stream.
for (size_t i = 0; i < copy_count; ++i) {
uint8 diff_byte = 0;
if (pending_diff_zeros) {
--pending_diff_zeros;
} else {
if (!diff_skips->ReadVarint32(&pending_diff_zeros))
return UNEXPECTED_ERROR;
if (!diff_bytes->Read(&diff_byte, 1))
return UNEXPECTED_ERROR;
}
uint8 byte = old_position[i] + diff_byte;
if (!new_stream->Write(&byte, 1))
return MEM_ERROR;
}
old_position += copy_count;
// Copy bytes from the extra block.
if (extra_count > static_cast<size_t>(extra_end - extra_position))
return UNEXPECTED_ERROR;
if (!new_stream->Write(extra_position, extra_count))
return MEM_ERROR;
extra_position += extra_count;
// "seek" forwards (or backwards) in oldfile.
if (old_position + seek_adjustment < old_start ||
old_position + seek_adjustment > old_end)
return UNEXPECTED_ERROR;
old_position += seek_adjustment;
}
if (!control_stream_copy_counts->Empty() ||
!control_stream_extra_counts->Empty() ||
!control_stream_seeks->Empty() ||
!diff_skips->Empty() ||
!diff_bytes->Empty() ||
!extra_bytes->Empty())
return UNEXPECTED_ERROR;
return OK;
}
BSDiffStatus ApplyBinaryPatch(SourceStream* old_stream,
SourceStream* patch_stream,
SinkStream* new_stream) {
MBSPatchHeader header;
BSDiffStatus ret = MBS_ReadHeader(patch_stream, &header);
if (ret != OK) return ret;
const uint8* old_start = old_stream->Buffer();
size_t old_size = old_stream->Remaining();
if (old_size != header.slen) return UNEXPECTED_ERROR;
if (CalculateCrc(old_start, old_size) != header.scrc32)
return CRC_ERROR;
MBS_ApplyPatch(&header, patch_stream, old_start, old_size, new_stream);
return OK;
}
BSDiffStatus ApplyBinaryPatch(const base::FilePath& old_file_path,
const base::FilePath& patch_file_path,
const base::FilePath& new_file_path) {
// Set up the old stream.
base::MemoryMappedFile old_file;
if (!old_file.Initialize(old_file_path)) {
return READ_ERROR;
}
SourceStream old_file_stream;
old_file_stream.Init(old_file.data(), old_file.length());
// Set up the patch stream.
base::MemoryMappedFile patch_file;
if (!patch_file.Initialize(patch_file_path)) {
return READ_ERROR;
}
SourceStream patch_file_stream;
patch_file_stream.Init(patch_file.data(), patch_file.length());
// Set up the new stream and apply the patch.
SinkStream new_sink_stream;
BSDiffStatus status = ApplyBinaryPatch(&old_file_stream,
&patch_file_stream,
&new_sink_stream);
if (status != OK) {
return status;
}
// Write the stream to disk.
int written = file_util::WriteFile(
new_file_path,
reinterpret_cast<const char*>(new_sink_stream.Buffer()),
static_cast<int>(new_sink_stream.Length()));
if (written != static_cast<int>(new_sink_stream.Length()))
return WRITE_ERROR;
return OK;
}
} // namespace