Add a util for converting ota payload to cow image
VAB team can use this tool to understand what real world COW images look
like, and perhaps write unittests
How to use this tool:
1. mm -j cow_converter
2. `unzip your_ota.zip payload.bin`
3. `unzip target_file.zip "IMAGES/*" -d /tmp/target_file
4. `cow_converter payload.bin /tmp/target_file/IMAGES`
5. inspect generated cow images `ls -l /tmp/target_file/IMAGES/*.cow`
Test: cow_converter payload.bin /tmp/target_file/IMAGES
Change-Id: I2c9d1ea566378e3350a048c40ff05a79d14873e8
diff --git a/aosp/cow_converter.cc b/aosp/cow_converter.cc
new file mode 100644
index 0000000..8c641b8
--- /dev/null
+++ b/aosp/cow_converter.cc
@@ -0,0 +1,131 @@
+//
+// Copyright (C) 2021 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.
+//
+
+#include <stdio.h>
+#include <string.h>
+
+#include <cstdint>
+#include <cstdio>
+#include <memory>
+
+#include <sys/fcntl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+
+#include <base/files/file_path.h>
+#include <libsnapshot/cow_writer.h>
+
+#include "update_engine/common/cow_operation_convert.h"
+#include "update_engine/common/utils.h"
+#include "update_engine/payload_consumer/file_descriptor.h"
+#include "update_engine/payload_consumer/payload_metadata.h"
+#include "update_engine/payload_generator/cow_size_estimator.h"
+#include "update_engine/update_metadata.pb.h"
+
+using android::snapshot::CowWriter;
+
+namespace chromeos_update_engine {
+
+bool ProcessPartition(const chromeos_update_engine::PartitionUpdate& partition,
+ const char* image_dir,
+ size_t block_size) {
+ base::FilePath img_dir{image_dir};
+ auto target_img = img_dir.Append(partition.partition_name() + ".img");
+ auto output_cow = img_dir.Append(partition.partition_name() + ".cow");
+ FileDescriptorPtr target_img_fd = std::make_shared<EintrSafeFileDescriptor>();
+ if (!target_img_fd->Open(target_img.value().c_str(), O_RDONLY)) {
+ PLOG(ERROR) << "Failed to open " << target_img.value();
+ return false;
+ }
+ android::base::unique_fd output_fd{
+ open(output_cow.value().c_str(), O_RDWR | O_CREAT, 0744)};
+ if (output_fd < 0) {
+ PLOG(ERROR) << "Failed to open " << output_cow.value();
+ return false;
+ }
+
+ android::snapshot::CowWriter cow_writer{
+ {.block_size = static_cast<uint32_t>(block_size), .compression = "gz"}};
+ TEST_AND_RETURN_FALSE(cow_writer.Initialize(output_fd));
+ TEST_AND_RETURN_FALSE(CowDryRun(target_img_fd,
+ partition.operations(),
+ partition.merge_operations(),
+ block_size,
+ &cow_writer));
+ TEST_AND_RETURN_FALSE(cow_writer.Finalize());
+ return true;
+}
+
+} // namespace chromeos_update_engine
+
+using chromeos_update_engine::MetadataParseResult;
+using chromeos_update_engine::PayloadMetadata;
+
+int main(int argc, const char* argv[]) {
+ if (argc != 3) {
+ printf("Usage: %s <payload.bin> <extracted target_file>\n", argv[0]);
+ return -1;
+ }
+ const char* payload_path = argv[1];
+ const char* images_dir = argv[2];
+ int payload_fd = open(payload_path, O_RDONLY);
+ if (payload_fd < 0) {
+ PLOG(ERROR) << "Failed to open payload file:";
+ return 1;
+ }
+ chromeos_update_engine::ScopedFdCloser closer{&payload_fd};
+ auto payload_size = chromeos_update_engine::utils::FileSize(payload_fd);
+ if (payload_size <= 0) {
+ PLOG(ERROR)
+ << "Couldn't determine size of payload file, or payload file is empty";
+ return 2;
+ }
+
+ PayloadMetadata payload_metadata;
+ auto payload = static_cast<unsigned char*>(
+ mmap(nullptr, payload_size, PROT_READ, MAP_PRIVATE, payload_fd, 0));
+
+ // C++ dark magic to ensure that |payload| is properly deallocated once the
+ // program exits.
+ auto munmap_deleter = [payload_size](auto payload) {
+ munmap(payload, payload_size);
+ };
+ std::unique_ptr<unsigned char, decltype(munmap_deleter)> munmapper{
+ payload, munmap_deleter};
+
+ if (payload == nullptr) {
+ PLOG(ERROR) << "Failed to mmap() payload file";
+ return 3;
+ }
+ if (payload_metadata.ParsePayloadHeader(payload, payload_size, nullptr) !=
+ chromeos_update_engine::MetadataParseResult::kSuccess) {
+ LOG(ERROR) << "Payload header parse failed!";
+ return 4;
+ }
+ chromeos_update_engine::DeltaArchiveManifest manifest;
+ if (!payload_metadata.GetManifest(payload, payload_size, &manifest)) {
+ LOG(ERROR) << "Failed to parse manifest!";
+ return 5;
+ }
+
+ for (const auto& partition : manifest.partitions()) {
+ LOG(INFO) << partition.partition_name();
+ if (!ProcessPartition(partition, images_dir, manifest.block_size())) {
+ return 6;
+ }
+ }
+ return 0;
+}