Merge "Reuse a same buffer per session instead of reallocating each time."... (803cd793) · Commits · e / os / android_frameworks_base

core/java/android/util/PackageUtils.java

+27 −13

Original line number	Diff line number	Diff line
		@@ -171,39 +171,53 @@ public final class PackageUtils {
		}

		/**
		* @see #computeSha256DigestForLargeFile(String, String)
		* Creates a fixed size buffer based on whether the device is low ram or not. This is to be used
		* with the {@link #computeSha256DigestForLargeFile(String, byte[])} and
		* {@link #computeSha256DigestForLargeFile(String, byte[], String)} methods.
		* @return a byte array of size {@link #LOW_RAM_BUFFER_SIZE_BYTES} if the device is a low RAM
		* device, otherwise a byte array of size {@link #HIGH_RAM_BUFFER_SIZE_BYTES}
		*/
		public static @Nullable String computeSha256DigestForLargeFile(@NonNull String filePath) {
		return computeSha256DigestForLargeFile(filePath, null);
		public static @NonNull byte[] createLargeFileBuffer() {
		int bufferSize = ActivityManager.isLowRamDeviceStatic()
		? LOW_RAM_BUFFER_SIZE_BYTES : HIGH_RAM_BUFFER_SIZE_BYTES;
		return new byte[bufferSize];
		}

		/**
		* Computes the SHA256 digest of large files.
		* @see #computeSha256DigestForLargeFile(String, byte[], String)
		*/
		public static @Nullable String computeSha256DigestForLargeFile(@NonNull String filePath,
		@NonNull byte[] fileBuffer) {
		return computeSha256DigestForLargeFile(filePath, fileBuffer, null);
		}

		/**
		* Computes the SHA256 digest of large files. This is typically useful for large APEXs.
		* @param filePath The path to which the file's content is to be hashed.
		* @param fileBuffer A buffer to read file's content into memory. It is strongly recommended to
		* make use of the {@link #createLargeFileBuffer()} method to create this
		* buffer.
		* @param separator Separator between each pair of characters, such as colon, or null to omit.
		* @return The digest or null if an error occurs.
		* @return The SHA256 digest or null if an error occurs.
		*/
		public static @Nullable String computeSha256DigestForLargeFile(@NonNull String filePath,
		@Nullable String separator) {
		@NonNull byte[] fileBuffer, @Nullable String separator) {
		MessageDigest messageDigest;
		try {
		messageDigest = MessageDigest.getInstance("SHA256");
		messageDigest.reset();
		} catch (NoSuchAlgorithmException e) {
		// this shouldn't happen!
		// this really shouldn't happen!
		return null;
		}

		boolean isLowRamDevice = ActivityManager.isLowRamDeviceStatic();
		int bufferSize = isLowRamDevice ? LOW_RAM_BUFFER_SIZE_BYTES : HIGH_RAM_BUFFER_SIZE_BYTES;

		File f = new File(filePath);
		try {
		DigestInputStream digestStream = new DigestInputStream(new FileInputStream(f),
		DigestInputStream digestInputStream = new DigestInputStream(new FileInputStream(f),
		messageDigest);
		byte[] buffer = new byte[bufferSize];
		while (digestStream.read(buffer) != -1);
		while (digestInputStream.read(fileBuffer) != -1);
		} catch (IOException e) {
		e.printStackTrace();
		return null;
		}

services/core/java/com/android/server/BinaryTransparencyService.java

+6 −3

Original line number	Diff line number	Diff line
		@@ -500,6 +500,7 @@ public class BinaryTransparencyService extends SystemService {
		// ones appearing out of the blue. Thus, we're going to only go through our cache to check
		// for changes, rather than freshly invoking `getInstalledPackages()` and
		// `getInstalledModules()`
		byte[] largeFileBuffer = PackageUtils.createLargeFileBuffer();
		for (Map.Entry<String, Long> entry : mBinaryLastUpdateTimes.entrySet()) {
		String packageName = entry.getKey();
		try {
		@@ -513,7 +514,7 @@ public class BinaryTransparencyService extends SystemService {

		// compute the digest for the updated package
		String sha256digest = PackageUtils.computeSha256DigestForLargeFile(
		packageInfo.applicationInfo.sourceDir);
		packageInfo.applicationInfo.sourceDir, largeFileBuffer);
		if (sha256digest == null) {
		Slog.e(TAG, "Failed to compute SHA256sum for file at "
		+ packageInfo.applicationInfo.sourceDir);
		@@ -545,11 +546,13 @@ public class BinaryTransparencyService extends SystemService {
		// In general, we care about all APEXs, and all Modules, which may include some APKs.

		// First, we deal with all installed APEXs.
		byte[] largeFileBuffer = PackageUtils.createLargeFileBuffer();
		for (PackageInfo packageInfo : getInstalledApexs()) {
		ApplicationInfo appInfo = packageInfo.applicationInfo;

		// compute SHA256 for these APEXs
		String sha256digest = PackageUtils.computeSha256DigestForLargeFile(appInfo.sourceDir);
		String sha256digest = PackageUtils.computeSha256DigestForLargeFile(appInfo.sourceDir,
		largeFileBuffer);
		if (sha256digest == null) {
		Slog.e(TAG, String.format("Failed to compute SHA256 digest for %s",
		packageInfo.packageName));
		@@ -585,7 +588,7 @@ public class BinaryTransparencyService extends SystemService {

		// compute SHA256 digest for these modules
		String sha256digest = PackageUtils.computeSha256DigestForLargeFile(
		appInfo.sourceDir);
		appInfo.sourceDir, largeFileBuffer);
		if (sha256digest == null) {
		Slog.e(TAG, String.format("Failed to compute SHA256 digest for %s",
		packageName));