diff options
Diffstat (limited to 'applypatch/imgpatch.cpp')
| -rw-r--r-- | applypatch/imgpatch.cpp | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/applypatch/imgpatch.cpp b/applypatch/imgpatch.cpp new file mode 100644 index 000000000..26888f8ee --- /dev/null +++ b/applypatch/imgpatch.cpp @@ -0,0 +1,234 @@ +/* + * Copyright (C) 2009 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +// See imgdiff.c in this directory for a description of the patch file +// format. + +#include <stdio.h> +#include <sys/cdefs.h> +#include <sys/stat.h> +#include <errno.h> +#include <malloc.h> +#include <unistd.h> +#include <string.h> + +#include "zlib.h" +#include "mincrypt/sha.h" +#include "applypatch.h" +#include "imgdiff.h" +#include "utils.h" + +/* + * Apply the patch given in 'patch_filename' to the source data given + * by (old_data, old_size). Write the patched output to the 'output' + * file, and update the SHA context with the output data as well. + * Return 0 on success. + */ +int ApplyImagePatch(const unsigned char* old_data, ssize_t old_size __unused, + const Value* patch, + SinkFn sink, void* token, SHA_CTX* ctx, + const Value* bonus_data) { + ssize_t pos = 12; + char* header = patch->data; + if (patch->size < 12) { + printf("patch too short to contain header\n"); + return -1; + } + + // IMGDIFF2 uses CHUNK_NORMAL, CHUNK_DEFLATE, and CHUNK_RAW. + // (IMGDIFF1, which is no longer supported, used CHUNK_NORMAL and + // CHUNK_GZIP.) + if (memcmp(header, "IMGDIFF2", 8) != 0) { + printf("corrupt patch file header (magic number)\n"); + return -1; + } + + int num_chunks = Read4(header+8); + + int i; + for (i = 0; i < num_chunks; ++i) { + // each chunk's header record starts with 4 bytes. + if (pos + 4 > patch->size) { + printf("failed to read chunk %d record\n", i); + return -1; + } + int type = Read4(patch->data + pos); + pos += 4; + + if (type == CHUNK_NORMAL) { + char* normal_header = patch->data + pos; + pos += 24; + if (pos > patch->size) { + printf("failed to read chunk %d normal header data\n", i); + return -1; + } + + size_t src_start = Read8(normal_header); + size_t src_len = Read8(normal_header+8); + size_t patch_offset = Read8(normal_header+16); + + ApplyBSDiffPatch(old_data + src_start, src_len, + patch, patch_offset, sink, token, ctx); + } else if (type == CHUNK_RAW) { + char* raw_header = patch->data + pos; + pos += 4; + if (pos > patch->size) { + printf("failed to read chunk %d raw header data\n", i); + return -1; + } + + ssize_t data_len = Read4(raw_header); + + if (pos + data_len > patch->size) { + printf("failed to read chunk %d raw data\n", i); + return -1; + } + if (ctx) SHA_update(ctx, patch->data + pos, data_len); + if (sink((unsigned char*)patch->data + pos, + data_len, token) != data_len) { + printf("failed to write chunk %d raw data\n", i); + return -1; + } + pos += data_len; + } else if (type == CHUNK_DEFLATE) { + // deflate chunks have an additional 60 bytes in their chunk header. + char* deflate_header = patch->data + pos; + pos += 60; + if (pos > patch->size) { + printf("failed to read chunk %d deflate header data\n", i); + return -1; + } + + size_t src_start = Read8(deflate_header); + size_t src_len = Read8(deflate_header+8); + size_t patch_offset = Read8(deflate_header+16); + size_t expanded_len = Read8(deflate_header+24); + size_t target_len = Read8(deflate_header+32); + int level = Read4(deflate_header+40); + int method = Read4(deflate_header+44); + int windowBits = Read4(deflate_header+48); + int memLevel = Read4(deflate_header+52); + int strategy = Read4(deflate_header+56); + + // Decompress the source data; the chunk header tells us exactly + // how big we expect it to be when decompressed. + + // Note: expanded_len will include the bonus data size if + // the patch was constructed with bonus data. The + // deflation will come up 'bonus_size' bytes short; these + // must be appended from the bonus_data value. + size_t bonus_size = (i == 1 && bonus_data != NULL) ? bonus_data->size : 0; + + unsigned char* expanded_source = reinterpret_cast<unsigned char*>(malloc(expanded_len)); + if (expanded_source == NULL) { + printf("failed to allocate %zu bytes for expanded_source\n", + expanded_len); + return -1; + } + + z_stream strm; + strm.zalloc = Z_NULL; + strm.zfree = Z_NULL; + strm.opaque = Z_NULL; + strm.avail_in = src_len; + strm.next_in = (unsigned char*)(old_data + src_start); + strm.avail_out = expanded_len; + strm.next_out = expanded_source; + + int ret; + ret = inflateInit2(&strm, -15); + if (ret != Z_OK) { + printf("failed to init source inflation: %d\n", ret); + return -1; + } + + // Because we've provided enough room to accommodate the output + // data, we expect one call to inflate() to suffice. + ret = inflate(&strm, Z_SYNC_FLUSH); + if (ret != Z_STREAM_END) { + printf("source inflation returned %d\n", ret); + return -1; + } + // We should have filled the output buffer exactly, except + // for the bonus_size. + if (strm.avail_out != bonus_size) { + printf("source inflation short by %zu bytes\n", strm.avail_out-bonus_size); + return -1; + } + inflateEnd(&strm); + + if (bonus_size) { + memcpy(expanded_source + (expanded_len - bonus_size), + bonus_data->data, bonus_size); + } + + // Next, apply the bsdiff patch (in memory) to the uncompressed + // data. + unsigned char* uncompressed_target_data; + ssize_t uncompressed_target_size; + if (ApplyBSDiffPatchMem(expanded_source, expanded_len, + patch, patch_offset, + &uncompressed_target_data, + &uncompressed_target_size) != 0) { + return -1; + } + + // Now compress the target data and append it to the output. + + // we're done with the expanded_source data buffer, so we'll + // reuse that memory to receive the output of deflate. + unsigned char* temp_data = expanded_source; + ssize_t temp_size = expanded_len; + if (temp_size < 32768) { + // ... unless the buffer is too small, in which case we'll + // allocate a fresh one. + free(temp_data); + temp_data = reinterpret_cast<unsigned char*>(malloc(32768)); + temp_size = 32768; + } + + // now the deflate stream + strm.zalloc = Z_NULL; + strm.zfree = Z_NULL; + strm.opaque = Z_NULL; + strm.avail_in = uncompressed_target_size; + strm.next_in = uncompressed_target_data; + ret = deflateInit2(&strm, level, method, windowBits, memLevel, strategy); + do { + strm.avail_out = temp_size; + strm.next_out = temp_data; + ret = deflate(&strm, Z_FINISH); + ssize_t have = temp_size - strm.avail_out; + + if (sink(temp_data, have, token) != have) { + printf("failed to write %ld compressed bytes to output\n", + (long)have); + return -1; + } + if (ctx) SHA_update(ctx, temp_data, have); + } while (ret != Z_STREAM_END); + deflateEnd(&strm); + + free(temp_data); + free(uncompressed_target_data); + } else { + printf("patch chunk %d is unknown type %d\n", i, type); + return -1; + } + } + + return 0; +} |