Merge "libsnapshot: Add a simple script and gtest to simulate power failures... (0bd13b7b) · Commits · e / os / android_system_core

fs_mgr/libsnapshot/Android.bp

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		@@ -226,3 +226,19 @@ cc_binary {
		"libutils",
		],
		}

		cc_test {
		name: "snapshot_power_test",
		srcs: [
		"power_test.cpp",
		],
		static_libs: [
		"libsnapshot",
		],
		shared_libs: [
		"libbase",
		"libfs_mgr_binder",
		"liblog",
		],
		gtest: false,
		}

fs_mgr/libsnapshot/PowerTest.md

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		snapshot\_power\_test
		---------------------

		snapshot\_power\_test is a standalone test to simulate power failures during a snapshot-merge operation.

		### Test Setup

		Start by creating two large files that will be used as the pre-merge and post-merge state. You can take two different partition images (for example, a product.img from two separate builds), or just create random data:

		dd if=/dev/urandom of=pre-merge count=1024 bs=1048576
		dd if=/dev/urandom of=post-merge count=1024 bs=1048576

		Next, push these files to an unencrypted directory on the device:

		adb push pre-merge /data/local/unencrypted
		adb push post-merge /data/local/unencrypted

		Next, run the test setup:

		adb sync data
		adb shell /data/nativetest64/snapshot_power_test/snapshot_power_test \
		/data/local/unencrypted/pre-merge \
		/data/local/unencrypted/post-merge

		This will create the necessary fiemap-based images.

		### Running
		The actual test can be run via `run_power_test.sh`. Its syntax is:

		run_power_test.sh <POST_MERGE_FILE>

		`POST_MERGE_FILE` should be the path on the device of the image to validate the merge against. Example:

		run_power_test.sh /data/local/unencrypted/post-merge

		The device will begin the merge with a 5% chance of injecting a kernel crash every 10ms. The device should be capable of rebooting normally without user intervention. Once the merge has completed, the test will run a final check command to validate the contents of the snapshot against the post-merge file. It will error if there are any incorrect blocks.

		Two environment variables can be passed to `run_power_test.sh`:
		1. `FAIL_RATE` - A fraction between 0 and 100 (inclusive) indicating the probability the device should inject a kernel crash every 10ms.
		2. `DEVICE_SERIAL` - If multiple devices are attached to adb, this argument is passed as the serial to select (to `adb -s`).

fs_mgr/libsnapshot/power_test.cpp

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		//
		// Copyright (C) 2020 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 <errno.h>
		#include <sys/stat.h>
		#include <sys/types.h>
		#include <unistd.h>

		#include <chrono>
		#include <iostream>
		#include <random>
		#include <string>
		#include <thread>
		#include <vector>

		#include <android-base/file.h>
		#include <android-base/parsedouble.h>
		#include <android-base/stringprintf.h>
		#include <android-base/strings.h>
		#include <android-base/unique_fd.h>
		#include <ext4_utils/ext4_utils.h>
		#include <fstab/fstab.h>
		#include <libdm/dm.h>
		#include <libfiemap/image_manager.h>

		using namespace std::chrono_literals;
		using namespace std::string_literals;
		using android::base::borrowed_fd;
		using android::base::unique_fd;
		using android::dm::DeviceMapper;
		using android::dm::DmDeviceState;
		using android::dm::DmTable;
		using android::dm::DmTargetSnapshot;
		using android::dm::SnapshotStorageMode;
		using android::fiemap::ImageManager;
		using android::fs_mgr::Fstab;

		namespace android {
		namespace snapshot {

		static void usage() {
		std::cerr << "Usage:\n";
		std::cerr << " create <orig-payload> <new-payload>\n";
		std::cerr << "\n";
		std::cerr << " Create a snapshot device containing the contents of\n";
		std::cerr << " orig-payload, and then write the contents of new-payload.\n";
		std::cerr << " The original files are not modified.\n";
		std::cerr << "\n";
		std::cerr << " merge <fail-rate>\n";
		std::cerr << "\n";
		std::cerr << " Merge the snapshot previously started by create, and wait\n";
		std::cerr << " for it to complete. Once done, it is compared to the\n";
		std::cerr << " new-payload for consistency. The original files are not \n";
		std::cerr << " modified. If a fail-rate is passed (as a fraction between 0\n";
		std::cerr << " and 100), every 10ms the device has that percent change of\n";
		std::cerr << " injecting a kernel crash.\n";
		std::cerr << "\n";
		std::cerr << " check <new-payload>\n";
		std::cerr << " Verify that all artifacts are correct after a merge\n";
		std::cerr << " completes.\n";
		std::cerr << "\n";
		std::cerr << " cleanup\n";
		std::cerr << " Remove all ImageManager artifacts from create/merge.\n";
		}

		class PowerTest final {
		public:
		PowerTest();
		bool Run(int argc, char** argv);

		private:
		bool OpenImageManager();
		bool Create(int argc, char** argv);
		bool Merge(int argc, char** argv);
		bool Check(int argc, char** argv);
		bool Cleanup();
		bool CleanupImage(const std::string& name);
		bool SetupImages(const std::string& first_file, borrowed_fd second_fd);
		bool MapImages();
		bool MapSnapshot(SnapshotStorageMode mode);
		bool GetMergeStatus(DmTargetSnapshot::Status* status);

		static constexpr char kSnapshotName[] = "snapshot-power-test";
		static constexpr char kSnapshotImageName[] = "snapshot-power-test-image";
		static constexpr char kSnapshotCowName[] = "snapshot-power-test-cow";

		DeviceMapper& dm_;
		std::unique_ptr<ImageManager> images_;
		std::string image_path_;
		std::string cow_path_;
		std::string snapshot_path_;
		};

		PowerTest::PowerTest() : dm_(DeviceMapper::Instance()) {}

		bool PowerTest::Run([[maybe_unused]] int argc, [[maybe_unused]] char** argv) {
		if (!OpenImageManager()) {
		return false;
		}

		if (argc < 2) {
		usage();
		return false;
		}
		if (argv[1] == "create"s) {
		return Create(argc, argv);
		} else if (argv[1] == "merge"s) {
		return Merge(argc, argv);
		} else if (argv[1] == "check"s) {
		return Check(argc, argv);
		} else if (argv[1] == "cleanup"s) {
		return Cleanup();
		} else {
		usage();
		return false;
		}
		}

		bool PowerTest::OpenImageManager() {
		std::vector<std::string> dirs = {
		"/data/gsi/test",
		"/metadata/gsi/test",
		};
		for (const auto& dir : dirs) {
		if (mkdir(dir.c_str(), 0700) && errno != EEXIST) {
		std::cerr << "mkdir " << dir << ": " << strerror(errno) << "\n";
		return false;
		}
		}

		images_ = ImageManager::Open("/metadata/gsi/test", "/data/gsi/test");
		if (!images_) {
		std::cerr << "Could not open ImageManager\n";
		return false;
		}
		return true;
		}

		bool PowerTest::Create(int argc, char** argv) {
		if (argc < 4) {
		usage();
		return false;
		}

		std::string first = argv[2];
		std::string second = argv[3];

		unique_fd second_fd(open(second.c_str(), O_RDONLY));
		if (second_fd < 0) {
		std::cerr << "open " << second << ": " << strerror(errno) << "\n";
		return false;
		}

		if (!Cleanup()) {
		return false;
		}
		if (!SetupImages(first, second_fd)) {
		return false;
		}
		if (!MapSnapshot(SnapshotStorageMode::Persistent)) {
		return false;
		}

		struct stat s;
		if (fstat(second_fd, &s)) {
		std::cerr << "fstat " << second << ": " << strerror(errno) << "\n";
		return false;
		}

		unique_fd snap_fd(open(snapshot_path_.c_str(), O_WRONLY));
		if (snap_fd < 0) {
		std::cerr << "open " << snapshot_path_ << ": " << strerror(errno) << "\n";
		return false;
		}

		uint8_t chunk[4096];
		uint64_t written = 0;
		while (written < s.st_size) {
		uint64_t remaining = s.st_size - written;
		size_t bytes = (size_t)std::min((uint64_t)sizeof(chunk), remaining);
		if (!android::base::ReadFully(second_fd, chunk, bytes)) {
		std::cerr << "read " << second << ": " << strerror(errno) << "\n";
		return false;
		}
		if (!android::base::WriteFully(snap_fd, chunk, bytes)) {
		std::cerr << "write " << snapshot_path_ << ": " << strerror(errno) << "\n";
		return false;
		}
		written += bytes;
		}
		if (fsync(snap_fd)) {
		std::cerr << "fsync: " << strerror(errno) << "\n";
		return false;
		}

		sync();

		snap_fd = {};
		if (!dm_.DeleteDeviceIfExists(kSnapshotName)) {
		std::cerr << "could not delete dm device " << kSnapshotName << "\n";
		return false;
		}
		if (!images_->UnmapImageIfExists(kSnapshotImageName)) {
		std::cerr << "failed to unmap " << kSnapshotImageName << "\n";
		return false;
		}
		if (!images_->UnmapImageIfExists(kSnapshotCowName)) {
		std::cerr << "failed to unmap " << kSnapshotImageName << "\n";
		return false;
		}
		return true;
		}

		bool PowerTest::Cleanup() {
		if (!dm_.DeleteDeviceIfExists(kSnapshotName)) {
		std::cerr << "could not delete dm device " << kSnapshotName << "\n";
		return false;
		}
		if (!CleanupImage(kSnapshotImageName) \|\| !CleanupImage(kSnapshotCowName)) {
		return false;
		}
		return true;
		}

		bool PowerTest::CleanupImage(const std::string& name) {
		if (!images_->UnmapImageIfExists(name)) {
		std::cerr << "failed to unmap " << name << "\n";
		return false;
		}
		if (images_->BackingImageExists(name) && !images_->DeleteBackingImage(name)) {
		std::cerr << "failed to delete " << name << "\n";
		return false;
		}
		return true;
		}

		bool PowerTest::SetupImages(const std::string& first, borrowed_fd second_fd) {
		unique_fd first_fd(open(first.c_str(), O_RDONLY));
		if (first_fd < 0) {
		std::cerr << "open " << first << ": " << strerror(errno) << "\n";
		return false;
		}

		struct stat s1, s2;
		if (fstat(first_fd.get(), &s1)) {
		std::cerr << "first stat: " << strerror(errno) << "\n";
		return false;
		}
		if (fstat(second_fd.get(), &s2)) {
		std::cerr << "second stat: " << strerror(errno) << "\n";
		return false;
		}

		// Pick the bigger size of both images, rounding up to the nearest block.
		uint64_t s1_size = (s1.st_size + 4095) & ~uint64_t(4095);
		uint64_t s2_size = (s2.st_size + 4095) & ~uint64_t(4095);
		uint64_t image_size = std::max(s1_size, s2_size) + (1024 * 1024 * 128);
		if (!images_->CreateBackingImage(kSnapshotImageName, image_size, 0, nullptr)) {
		std::cerr << "failed to create " << kSnapshotImageName << "\n";
		return false;
		}
		// Use the same size for the cow.
		if (!images_->CreateBackingImage(kSnapshotCowName, image_size, 0, nullptr)) {
		std::cerr << "failed to create " << kSnapshotCowName << "\n";
		return false;
		}
		if (!MapImages()) {
		return false;
		}

		unique_fd image_fd(open(image_path_.c_str(), O_WRONLY));
		if (image_fd < 0) {
		std::cerr << "open: " << image_path_ << ": " << strerror(errno) << "\n";
		return false;
		}

		uint8_t chunk[4096];
		uint64_t written = 0;
		while (written < s1.st_size) {
		uint64_t remaining = s1.st_size - written;
		size_t bytes = (size_t)std::min((uint64_t)sizeof(chunk), remaining);
		if (!android::base::ReadFully(first_fd, chunk, bytes)) {
		std::cerr << "read: " << strerror(errno) << "\n";
		return false;
		}
		if (!android::base::WriteFully(image_fd, chunk, bytes)) {
		std::cerr << "write: " << strerror(errno) << "\n";
		return false;
		}
		written += bytes;
		}
		if (fsync(image_fd)) {
		std::cerr << "fsync: " << strerror(errno) << "\n";
		return false;
		}

		// Zero the first block of the COW.
		unique_fd cow_fd(open(cow_path_.c_str(), O_WRONLY));
		if (cow_fd < 0) {
		std::cerr << "open: " << cow_path_ << ": " << strerror(errno) << "\n";
		return false;
		}

		memset(chunk, 0, sizeof(chunk));
		if (!android::base::WriteFully(cow_fd, chunk, sizeof(chunk))) {
		std::cerr << "read: " << strerror(errno) << "\n";
		return false;
		}
		if (fsync(cow_fd)) {
		std::cerr << "fsync: " << strerror(errno) << "\n";
		return false;
		}
		return true;
		}

		bool PowerTest::MapImages() {
		if (!images_->MapImageDevice(kSnapshotImageName, 10s, &image_path_)) {
		std::cerr << "failed to map " << kSnapshotImageName << "\n";
		return false;
		}
		if (!images_->MapImageDevice(kSnapshotCowName, 10s, &cow_path_)) {
		std::cerr << "failed to map " << kSnapshotCowName << "\n";
		return false;
		}
		return true;
		}

		bool PowerTest::MapSnapshot(SnapshotStorageMode mode) {
		uint64_t sectors;
		{
		unique_fd fd(open(image_path_.c_str(), O_RDONLY));
		if (fd < 0) {
		std::cerr << "open: " << image_path_ << ": " << strerror(errno) << "\n";
		return false;
		}
		sectors = get_block_device_size(fd) / 512;
		}

		DmTable table;
		table.Emplace<DmTargetSnapshot>(0, sectors, image_path_, cow_path_, mode, 8);
		if (!dm_.CreateDevice(kSnapshotName, table, &snapshot_path_, 10s)) {
		std::cerr << "failed to create snapshot device\n";
		return false;
		}
		return true;
		}

		bool PowerTest::GetMergeStatus(DmTargetSnapshot::Status* status) {
		std::vector<DeviceMapper::TargetInfo> targets;
		if (!dm_.GetTableStatus(kSnapshotName, &targets)) {
		std::cerr << "failed to get merge status\n";
		return false;
		}
		if (targets.size() != 1) {
		std::cerr << "merge device has wrong number of targets\n";
		return false;
		}
		if (!DmTargetSnapshot::ParseStatusText(targets[0].data, status)) {
		std::cerr << "could not parse merge target status text\n";
		return false;
		}
		return true;
		}

		static std::string GetUserdataBlockDeviceName() {
		Fstab fstab;
		if (!ReadFstabFromFile("/proc/mounts", &fstab)) {
		return {};
		}

		auto entry = android::fs_mgr::GetEntryForMountPoint(&fstab, "/data");
		if (!entry) {
		return {};
		}

		auto prefix = "/dev/block/"s;
		if (!android::base::StartsWith(entry->blk_device, prefix)) {
		return {};
		}
		return entry->blk_device.substr(prefix.size());
		}

		bool PowerTest::Merge(int argc, char** argv) {
		// Start an f2fs GC to really stress things. :TODO: figure out data device
		auto userdata_dev = GetUserdataBlockDeviceName();
		if (userdata_dev.empty()) {
		std::cerr << "could not locate userdata block device\n";
		return false;
		}

		auto cmd =
		android::base::StringPrintf("echo 1 > /sys/fs/f2fs/%s/gc_urgent", userdata_dev.c_str());
		system(cmd.c_str());

		if (dm_.GetState(kSnapshotName) == DmDeviceState::INVALID) {
		if (!MapImages()) {
		return false;
		}
		if (!MapSnapshot(SnapshotStorageMode::Merge)) {
		return false;
		}
		}

		std::random_device r;
		std::default_random_engine re(r());
		std::uniform_real_distribution<double> dist(0.0, 100.0);

		std::optional<double> failure_rate;
		if (argc >= 3) {
		double d;
		if (!android::base::ParseDouble(argv[2], &d)) {
		std::cerr << "Could not parse failure rate as double: " << argv[2] << "\n";
		return false;
		}
		failure_rate = d;
		}

		while (true) {
		DmTargetSnapshot::Status status;
		if (!GetMergeStatus(&status)) {
		return false;
		}
		if (!status.error.empty()) {
		std::cerr << "merge reported error: " << status.error << "\n";
		return false;
		}
		if (status.sectors_allocated == status.metadata_sectors) {
		break;
		}

		std::cerr << status.sectors_allocated << " / " << status.metadata_sectors << "\n";

		if (failure_rate && *failure_rate >= dist(re)) {
		system("echo 1 > /proc/sys/kernel/sysrq");
		system("echo c > /proc/sysrq-trigger");
		}

		std::this_thread::sleep_for(10ms);
		}

		std::cout << "Merge completed.\n";
		return true;
		}

		bool PowerTest::Check([[maybe_unused]] int argc, [[maybe_unused]] char** argv) {
		if (argc < 3) {
		std::cerr << "Expected argument: <new-image-path>\n";
		return false;
		}
		std::string md_path, image_path;
		std::string canonical_path = argv[2];

		if (!dm_.GetDmDevicePathByName(kSnapshotName, &md_path)) {
		std::cerr << "could not get dm-path for merge device\n";
		return false;
		}
		if (!images_->GetMappedImageDevice(kSnapshotImageName, &image_path)) {
		std::cerr << "could not get image path\n";
		return false;
		}

		unique_fd md_fd(open(md_path.c_str(), O_RDONLY));
		if (md_fd < 0) {
		std::cerr << "open: " << md_path << ": " << strerror(errno) << "\n";
		return false;
		}
		unique_fd image_fd(open(image_path.c_str(), O_RDONLY));
		if (image_fd < 0) {
		std::cerr << "open: " << image_path << ": " << strerror(errno) << "\n";
		return false;
		}
		unique_fd canonical_fd(open(canonical_path.c_str(), O_RDONLY));
		if (canonical_fd < 0) {
		std::cerr << "open: " << canonical_path << ": " << strerror(errno) << "\n";
		return false;
		}

		struct stat s;
		if (fstat(canonical_fd, &s)) {
		std::cerr << "fstat: " << canonical_path << ": " << strerror(errno) << "\n";
		return false;
		}
		uint64_t canonical_size = s.st_size;
		uint64_t md_size = get_block_device_size(md_fd);
		uint64_t image_size = get_block_device_size(image_fd);
		if (image_size != md_size) {
		std::cerr << "image size does not match merge device size\n";
		return false;
		}
		if (canonical_size > image_size) {
		std::cerr << "canonical size " << canonical_size << " is greater than image size "
		<< image_size << "\n";
		return false;
		}

		constexpr size_t kBlockSize = 4096;
		uint8_t canonical_buffer[kBlockSize];
		uint8_t image_buffer[kBlockSize];
		uint8_t md_buffer[kBlockSize];

		uint64_t remaining = canonical_size;
		uint64_t blockno = 0;
		while (remaining) {
		size_t bytes = (size_t)std::min((uint64_t)kBlockSize, remaining);
		if (!android::base::ReadFully(canonical_fd, canonical_buffer, bytes)) {
		std::cerr << "read: " << canonical_buffer << ": " << strerror(errno) << "\n";
		return false;
		}
		if (!android::base::ReadFully(image_fd, image_buffer, bytes)) {
		std::cerr << "read: " << image_buffer << ": " << strerror(errno) << "\n";
		return false;
		}
		if (!android::base::ReadFully(md_fd, md_buffer, bytes)) {
		std::cerr << "read: " << md_buffer << ": " << strerror(errno) << "\n";
		return false;
		}
		if (memcmp(canonical_buffer, image_buffer, bytes)) {
		std::cerr << "canonical and image differ at block " << blockno << "\n";
		return false;
		}
		if (memcmp(canonical_buffer, md_buffer, bytes)) {
		std::cerr << "canonical and image differ at block " << blockno << "\n";
		return false;
		}

		remaining -= bytes;
		blockno++;
		}

		std::cout << "Images all match.\n";
		return true;
		}

		} // namespace snapshot
		} // namespace android

		int main(int argc, char** argv) {
		android::snapshot::PowerTest test;

		if (!test.Run(argc, argv)) {
		std::cerr << "Unexpected error running test." << std::endl;
		return 1;
		}
		fflush(stdout);
		return 0;
		}

fs_mgr/libsnapshot/run_power_test.sh

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Original line number	Diff line number	Diff line
		#!/bin/bash

		set -e

		if [ -z "$FAIL_RATE" ]; then
		FAIL_RATE=5.0
		fi
		if [ ! -z "$ANDROID_SERIAL" ]; then
		DEVICE_ARGS=-s $ANDROID_SERIAL
		else
		DEVICE_ARGS=
		fi

		TEST_BIN=/data/nativetest64/snapshot_power_test/snapshot_power_test

		while :
		do
		adb $DEVICE_ARGS wait-for-device
		adb $DEVICE_ARGS root
		adb $DEVICE_ARGS shell rm $TEST_BIN
		adb $DEVICE_ARGS sync data
		set +e
		output=$(adb $DEVICE_ARGS shell $TEST_BIN merge $FAIL_RATE 2>&1)
		set -e
		if [[ "$output" == "Merge completed" ]]; then
		echo "Merge completed."
		break
		fi
		if [[ "$output" == "Unexpected error" ]]; then
		echo "Unexpected error."
		exit 1
		fi
		done

		adb $DEVICE_ARGS shell $TEST_BIN check $1