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Commit 7de862f4 authored by Jeff Sharkey's avatar Jeff Sharkey
Browse files

Baseline `StrictMode` on Ravenwood. 

We've uncovered several utilities that temporarily clear any
read/write thread policies.  Instead of making them all side-step
their StictMode interactions on Ravenwood, this change offers just
enough of a baseline implementation to support them; it doesn't
actually offer to detect anything.

Bug: 318833612
Test: atest FrameworksCoreTestsRavenwood
Change-Id: I5e406e24fcd5e83d108006ca6c7d08c0534297a9
parent 919032ef

core/java/android/os/FileUtils.java

+0 −9
Original line number Diff line number Diff line
@@ -800,7 +800,6 @@ public final class FileUtils { 
     *

     * @hide

     */

    @android.ravenwood.annotation.RavenwoodReplace

    public static void bytesToFile(String filename, byte[] content) throws IOException {

        if (filename.startsWith("/proc/")) {

            final int oldMask = StrictMode.allowThreadDiskWritesMask();
@@ -816,14 +815,6 @@ public final class FileUtils { 
        }

    }



    /** @hide */

    public static void bytesToFile$ravenwood(String filename, byte[] content) throws IOException {

        // No StrictMode support, so we can just directly write

        try (FileOutputStream fos = new FileOutputStream(filename)) {

            fos.write(content);

        }

    }



    /**

     * Writes string to file. Basically same as "echo -n $string > $filename"

     *

core/java/android/os/StrictMode.java

+18 −0
Original line number Diff line number Diff line
@@ -77,6 +77,7 @@ import com.android.internal.os.BackgroundThread; 
import com.android.internal.os.RuntimeInit;

import com.android.internal.util.FastPrintWriter;

import com.android.internal.util.HexDump;

import com.android.internal.util.Preconditions;



import dalvik.system.BlockGuard;

import dalvik.system.CloseGuard;
@@ -154,6 +155,7 @@ import java.util.function.Consumer; 
 * android.os.Binder} calls, it's still ultimately a best effort mechanism. Notably, disk or network

 * access from JNI calls won't necessarily trigger it.

 */

@android.ravenwood.annotation.RavenwoodKeepPartialClass

public final class StrictMode {

    private static final String TAG = "StrictMode";

    private static final boolean LOG_V = Log.isLoggable(TAG, Log.VERBOSE);
@@ -1267,6 +1269,7 @@ public final class StrictMode { 
    }



    /** @hide */

    @android.ravenwood.annotation.RavenwoodReplace

    public static void setThreadPolicyMask(@ThreadPolicyMask int threadPolicyMask) {

        // In addition to the Java-level thread-local in Dalvik's

        // BlockGuard, we also need to keep a native thread-local in
@@ -1279,6 +1282,12 @@ public final class StrictMode { 
        Binder.setThreadStrictModePolicy(threadPolicyMask);

    }



    /** @hide */

    public static void setThreadPolicyMask$ravenwood(@ThreadPolicyMask int threadPolicyMask) {

        // Ravenwood currently doesn't support any detection modes

        Preconditions.checkFlagsArgument(threadPolicyMask, 0);

    }



    // Sets the policy in Dalvik/libcore (BlockGuard)

    private static void setBlockGuardPolicy(@ThreadPolicyMask int threadPolicyMask) {

        if (threadPolicyMask == 0) {
@@ -1321,6 +1330,7 @@ public final class StrictMode { 
     * @hide

     */

    @UnsupportedAppUsage

    @android.ravenwood.annotation.RavenwoodReplace

    public static @ThreadPolicyMask int getThreadPolicyMask() {

        final BlockGuard.Policy policy = BlockGuard.getThreadPolicy();

        if (policy instanceof AndroidBlockGuardPolicy) {
@@ -1330,6 +1340,12 @@ public final class StrictMode { 
        }

    }



    /** @hide */

    public static @ThreadPolicyMask int getThreadPolicyMask$ravenwood() {

        // Ravenwood currently doesn't support any detection modes

        return 0;

    }



    /** Returns the current thread's policy. */

    public static ThreadPolicy getThreadPolicy() {

        // TODO: this was a last minute Gingerbread API change (to
@@ -1359,6 +1375,7 @@ public final class StrictMode { 
    }



    /** @hide */

    @android.ravenwood.annotation.RavenwoodKeep

    public static @ThreadPolicyMask int allowThreadDiskWritesMask() {

        int oldPolicyMask = getThreadPolicyMask();

        int newPolicyMask = oldPolicyMask & ~(DETECT_THREAD_DISK_WRITE | DETECT_THREAD_DISK_READ);
@@ -1383,6 +1400,7 @@ public final class StrictMode { 
    }



    /** @hide */

    @android.ravenwood.annotation.RavenwoodKeep

    public static @ThreadPolicyMask int allowThreadDiskReadsMask() {

        int oldPolicyMask = getThreadPolicyMask();

        int newPolicyMask = oldPolicyMask & ~(DETECT_THREAD_DISK_READ);

core/java/com/android/internal/os/ProcStatsUtil.java

+2 −8
Original line number Diff line number Diff line
@@ -93,23 +93,17 @@ public final class ProcStatsUtil { 
     * seen, or at the end of the file

     */

    @Nullable

    @android.ravenwood.annotation.RavenwoodReplace

    public static String readTerminatedProcFile(String path, byte terminator) {

        // Permit disk reads here, as /proc isn't really "on disk" and should be fast.

        // TODO: make BlockGuard ignore /proc/ and /sys/ files perhaps?

        final StrictMode.ThreadPolicy savedPolicy = StrictMode.allowThreadDiskReads();

        final int savedPolicy = StrictMode.allowThreadDiskReadsMask();

        try {

            return readTerminatedProcFileInternal(path, terminator);

        } finally {

            StrictMode.setThreadPolicy(savedPolicy);

            StrictMode.setThreadPolicyMask(savedPolicy);

        }

    }



    public static String readTerminatedProcFile$ravenwood(String path, byte terminator) {

        // No StrictMode under Ravenwood

        return readTerminatedProcFileInternal(path, terminator);

    }



    private static String readTerminatedProcFileInternal(String path, byte terminator) {

        try (FileInputStream is = new FileInputStream(path)) {

            ByteArrayOutputStream byteStream = null;

core/java/com/android/internal/os/StoragedUidIoStatsReader.java

+0 −5
Original line number Diff line number Diff line
@@ -74,7 +74,6 @@ public class StoragedUidIoStatsReader { 
     *

     * @param callback The callback to invoke for each line of the proc file.

     */

    @android.ravenwood.annotation.RavenwoodReplace

    public void readAbsolute(Callback callback) {

        final int oldMask = StrictMode.allowThreadDiskReadsMask();

        try {
@@ -84,10 +83,6 @@ public class StoragedUidIoStatsReader { 
        }

    }



    public void readAbsolute$ravenwood(Callback callback) {

        readAbsoluteInternal(callback);

    }



    private void readAbsoluteInternal(Callback callback) {

        File file = new File(sUidIoFile);

        try (BufferedReader reader = Files.newBufferedReader(file.toPath())) {

core/tests/coretests/src/android/os/StrictModeTest.java

0 → 100644
+63 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2024 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.

 */



package android.os;



import static org.junit.Assert.assertEquals;



import androidx.test.runner.AndroidJUnit4;



import org.junit.Before;

import org.junit.Test;

import org.junit.runner.RunWith;



import java.io.File;



@RunWith(AndroidJUnit4.class)

public class StrictModeTest {

    private File mFile;



    @Before

    public void setUp() throws Exception {

        mFile = File.createTempFile("StrictModeTest", "tmp");

    }



    @Test

    public void testAllowThreadDiskReadsMask() throws Exception {

        final int mask = StrictMode.allowThreadDiskReadsMask();

        try {

            mFile.exists();

        } finally {

            StrictMode.setThreadPolicyMask(mask);

        }

    }



    @Test

    public void testAllowThreadDiskWritesMask() throws Exception {

        final int mask = StrictMode.allowThreadDiskReadsMask();

        try {

            mFile.delete();

        } finally {

            StrictMode.setThreadPolicyMask(mask);

        }

    }



    @Test

    public void testThreadMask() throws Exception {

        StrictMode.setThreadPolicyMask(0);

        assertEquals(0, StrictMode.getThreadPolicyMask());

    }

}