240 lines
8.9 KiB
C++
240 lines
8.9 KiB
C++
/*
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* Copyright (C) 2009 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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// See imgdiff.c in this directory for a description of the patch file
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// format.
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#include <stdio.h>
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#include <sys/cdefs.h>
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#include <sys/stat.h>
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#include <errno.h>
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#include <unistd.h>
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#include <string.h>
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#include <vector>
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#include "zlib.h"
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#include "openssl/sha.h"
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#include "applypatch.h"
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#include "imgdiff.h"
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#include "utils.h"
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int ApplyImagePatch(const unsigned char* old_data, ssize_t old_size,
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const unsigned char* patch_data, ssize_t patch_size,
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SinkFn sink, void* token) {
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Value patch = {VAL_BLOB, patch_size,
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reinterpret_cast<char*>(const_cast<unsigned char*>(patch_data))};
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return ApplyImagePatch(
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old_data, old_size, &patch, sink, token, nullptr, nullptr);
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}
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/*
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* Apply the patch given in 'patch_filename' to the source data given
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* by (old_data, old_size). Write the patched output to the 'output'
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* file, and update the SHA context with the output data as well.
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* Return 0 on success.
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*/
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int ApplyImagePatch(const unsigned char* old_data, ssize_t old_size,
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const Value* patch,
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SinkFn sink, void* token, SHA_CTX* ctx,
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const Value* bonus_data) {
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ssize_t pos = 12;
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char* header = patch->data;
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if (patch->size < 12) {
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printf("patch too short to contain header\n");
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return -1;
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}
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// IMGDIFF2 uses CHUNK_NORMAL, CHUNK_DEFLATE, and CHUNK_RAW.
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// (IMGDIFF1, which is no longer supported, used CHUNK_NORMAL and
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// CHUNK_GZIP.)
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if (memcmp(header, "IMGDIFF2", 8) != 0) {
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printf("corrupt patch file header (magic number)\n");
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return -1;
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}
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int num_chunks = Read4(header+8);
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int i;
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for (i = 0; i < num_chunks; ++i) {
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// each chunk's header record starts with 4 bytes.
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if (pos + 4 > patch->size) {
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printf("failed to read chunk %d record\n", i);
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return -1;
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}
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int type = Read4(patch->data + pos);
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pos += 4;
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if (type == CHUNK_NORMAL) {
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char* normal_header = patch->data + pos;
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pos += 24;
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if (pos > patch->size) {
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printf("failed to read chunk %d normal header data\n", i);
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return -1;
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}
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size_t src_start = Read8(normal_header);
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size_t src_len = Read8(normal_header+8);
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size_t patch_offset = Read8(normal_header+16);
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if (src_start + src_len > static_cast<size_t>(old_size)) {
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printf("source data too short\n");
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return -1;
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}
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ApplyBSDiffPatch(old_data + src_start, src_len,
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patch, patch_offset, sink, token, ctx);
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} else if (type == CHUNK_RAW) {
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char* raw_header = patch->data + pos;
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pos += 4;
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if (pos > patch->size) {
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printf("failed to read chunk %d raw header data\n", i);
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return -1;
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}
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ssize_t data_len = Read4(raw_header);
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if (pos + data_len > patch->size) {
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printf("failed to read chunk %d raw data\n", i);
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return -1;
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}
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if (ctx) SHA1_Update(ctx, patch->data + pos, data_len);
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if (sink((unsigned char*)patch->data + pos,
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data_len, token) != data_len) {
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printf("failed to write chunk %d raw data\n", i);
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return -1;
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}
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pos += data_len;
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} else if (type == CHUNK_DEFLATE) {
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// deflate chunks have an additional 60 bytes in their chunk header.
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char* deflate_header = patch->data + pos;
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pos += 60;
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if (pos > patch->size) {
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printf("failed to read chunk %d deflate header data\n", i);
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return -1;
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}
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size_t src_start = Read8(deflate_header);
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size_t src_len = Read8(deflate_header+8);
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size_t patch_offset = Read8(deflate_header+16);
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size_t expanded_len = Read8(deflate_header+24);
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int level = Read4(deflate_header+40);
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int method = Read4(deflate_header+44);
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int windowBits = Read4(deflate_header+48);
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int memLevel = Read4(deflate_header+52);
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int strategy = Read4(deflate_header+56);
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if (src_start + src_len > static_cast<size_t>(old_size)) {
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printf("source data too short\n");
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return -1;
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}
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// Decompress the source data; the chunk header tells us exactly
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// how big we expect it to be when decompressed.
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// Note: expanded_len will include the bonus data size if
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// the patch was constructed with bonus data. The
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// deflation will come up 'bonus_size' bytes short; these
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// must be appended from the bonus_data value.
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size_t bonus_size = (i == 1 && bonus_data != NULL) ? bonus_data->size : 0;
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std::vector<unsigned char> expanded_source(expanded_len);
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z_stream strm;
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strm.zalloc = Z_NULL;
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strm.zfree = Z_NULL;
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strm.opaque = Z_NULL;
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strm.avail_in = src_len;
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strm.next_in = (unsigned char*)(old_data + src_start);
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strm.avail_out = expanded_len;
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strm.next_out = expanded_source.data();
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int ret;
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ret = inflateInit2(&strm, -15);
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if (ret != Z_OK) {
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printf("failed to init source inflation: %d\n", ret);
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return -1;
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}
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// Because we've provided enough room to accommodate the output
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// data, we expect one call to inflate() to suffice.
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ret = inflate(&strm, Z_SYNC_FLUSH);
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if (ret != Z_STREAM_END) {
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printf("source inflation returned %d\n", ret);
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return -1;
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}
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// We should have filled the output buffer exactly, except
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// for the bonus_size.
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if (strm.avail_out != bonus_size) {
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printf("source inflation short by %zu bytes\n", strm.avail_out-bonus_size);
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return -1;
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}
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inflateEnd(&strm);
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if (bonus_size) {
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memcpy(expanded_source.data() + (expanded_len - bonus_size),
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bonus_data->data, bonus_size);
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}
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// Next, apply the bsdiff patch (in memory) to the uncompressed
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// data.
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std::vector<unsigned char> uncompressed_target_data;
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if (ApplyBSDiffPatchMem(expanded_source.data(), expanded_len,
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patch, patch_offset,
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&uncompressed_target_data) != 0) {
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return -1;
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}
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// Now compress the target data and append it to the output.
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// we're done with the expanded_source data buffer, so we'll
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// reuse that memory to receive the output of deflate.
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if (expanded_source.size() < 32768U) {
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expanded_source.resize(32768U);
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}
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std::vector<unsigned char>& temp_data = expanded_source;
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// now the deflate stream
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strm.zalloc = Z_NULL;
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strm.zfree = Z_NULL;
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strm.opaque = Z_NULL;
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strm.avail_in = uncompressed_target_data.size();
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strm.next_in = uncompressed_target_data.data();
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ret = deflateInit2(&strm, level, method, windowBits, memLevel, strategy);
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if (ret != Z_OK) {
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printf("failed to init uncompressed data deflation: %d\n", ret);
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return -1;
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}
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do {
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strm.avail_out = temp_data.size();
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strm.next_out = temp_data.data();
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ret = deflate(&strm, Z_FINISH);
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ssize_t have = temp_data.size() - strm.avail_out;
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if (sink(temp_data.data(), have, token) != have) {
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printf("failed to write %ld compressed bytes to output\n",
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(long)have);
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return -1;
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}
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if (ctx) SHA1_Update(ctx, temp_data.data(), have);
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} while (ret != Z_STREAM_END);
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deflateEnd(&strm);
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} else {
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printf("patch chunk %d is unknown type %d\n", i, type);
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return -1;
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}
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}
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return 0;
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}
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