Add instrumentation listener for native coverage
Due to current limitations native code coverage is not collected
automatically at the end of Java tests that use JNI. This is worked
around in tests by using an InstrumentationListener that manually
triggers coverage collection at the end of a run.
Add a common module utility for that task, so that all modules do not
need to have their own copy, as is currently the case for tests using
such an utility.
The NativeCoverageInstrumentationListener code is extracted from the
current ConscryptInstrumentationListener.
Bug: 185074329
Test: atest NetworkStackCoverageTests using the utility
Change-Id: I6ea9fb04bade2567c7079443e09710f69df2e9b8
diff --git a/java/com/android/modules/utils/testing/Android.bp b/java/com/android/modules/utils/testing/Android.bp
new file mode 100644
index 0000000..28bd82c
--- /dev/null
+++ b/java/com/android/modules/utils/testing/Android.bp
@@ -0,0 +1,29 @@
+//
+// 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.
+
+package {
+ default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+java_library {
+ name: "modules-utils-native-coverage-listener",
+ srcs: ["NativeCoverageHackInstrumentationListener.java"],
+ static_libs: [
+ "androidx.test.rules",
+ ],
+ sdk_version: "test_current",
+ min_sdk_version: "29",
+ visibility: ["//visibility:public"],
+}
diff --git a/java/com/android/modules/utils/testing/NativeCoverageHackInstrumentationListener.java b/java/com/android/modules/utils/testing/NativeCoverageHackInstrumentationListener.java
new file mode 100644
index 0000000..438789a
--- /dev/null
+++ b/java/com/android/modules/utils/testing/NativeCoverageHackInstrumentationListener.java
@@ -0,0 +1,233 @@
+/*
+ * 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
+ */
+
+package com.android.modules.utils.testing;
+
+import android.system.ErrnoException;
+import android.system.Os;
+import android.util.Log;
+
+import androidx.test.internal.runner.listener.InstrumentationRunListener;
+
+import org.junit.runner.Result;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Instrumentation listener that dumps Clang coverage when the test run finishes.
+ *
+ * This is necessary as native coverage is not dumped automatically after Java/JNI tests
+ * (b/185074329) and should be replaced by more generic solutions (b/185822084).
+ */
+public class NativeCoverageHackInstrumentationListener extends InstrumentationRunListener {
+ private static final String LOG_TAG =
+ NativeCoverageHackInstrumentationListener.class.getSimpleName();
+ // Signal used to trigger a dump of Clang coverage information.
+ // See {@code maybeDumpNativeCoverage} below.
+ private static final int COVERAGE_SIGNAL = 37;
+
+ @Override
+ public void testRunFinished(Result result) throws Exception {
+ maybeDumpNativeCoverage();
+ super.testRunFinished(result);
+ }
+
+ /**
+ * If this test process is instrumented for native coverage, then trigger a dump
+ * of the coverage data and wait until either we detect the dumping has finished or 60 seconds,
+ * whichever is shorter.
+ *
+ * Background: Coverage builds install a signal handler for signal 37 which flushes coverage
+ * data to disk, which may take a few seconds. Tests running as an app process will get
+ * killed with SIGKILL once the app code exits, even if the coverage handler is still running.
+ *
+ * Method: If a handler is installed for signal 37, then assume this is a coverage run and
+ * send signal 37. The handler is non-reentrant and so signal 37 will then be blocked until
+ * the handler completes. So after we send the signal, we loop checking the blocked status
+ * for signal 37 until we hit the 60 second deadline. If the signal is blocked then sleep for
+ * 2 seconds, and if it becomes unblocked then the handler exitted so we can return early.
+ * If the signal is not blocked at the start of the loop then most likely the handler has
+ * not yet been invoked. This should almost never happen as it should get blocked on delivery
+ * when we call {@code Os.kill()}, so sleep for a shorter duration (100ms) and try again. There
+ * is a race condition here where the handler is delayed but then runs for less than 100ms and
+ * gets missed, in which case this method will loop with 100ms sleeps until the deadline.
+ *
+ * In the case where the handler runs for more than 60 seconds, the test process will be allowed
+ * to exit so coverage information may be incomplete.
+ *
+ * There is no API for determining signal dispositions, so this method uses the
+ * {@link SignalMaskInfo} class to read the data from /proc. If there is an error parsing
+ * the /proc data then this method will also loop until the 60s deadline passes.
+ */
+ private void maybeDumpNativeCoverage() {
+ SignalMaskInfo siginfo = new SignalMaskInfo();
+ if (!siginfo.isValid()) {
+ Log.e(LOG_TAG, "Invalid signal info");
+ return;
+ }
+
+ if (!siginfo.isCaught(COVERAGE_SIGNAL)) {
+ // Process is not instrumented for coverage
+ Log.i(LOG_TAG, "Not dumping coverage, no handler installed");
+ return;
+ }
+
+ Log.i(LOG_TAG,
+ String.format("Sending coverage dump signal %d to pid %d uid %d", COVERAGE_SIGNAL,
+ Os.getpid(), Os.getuid()));
+ try {
+ Os.kill(Os.getpid(), COVERAGE_SIGNAL);
+ } catch (ErrnoException e) {
+ Log.e(LOG_TAG, "Unable to send coverage signal", e);
+ return;
+ }
+
+ long start = System.currentTimeMillis();
+ long deadline = start + 60 * 1000L;
+ while (System.currentTimeMillis() < deadline) {
+ siginfo.refresh();
+ try {
+ if (siginfo.isValid() && siginfo.isBlocked(COVERAGE_SIGNAL)) {
+ // Signal is currently blocked so assume a handler is running
+ Thread.sleep(2000L);
+ siginfo.refresh();
+ if (siginfo.isValid() && !siginfo.isBlocked(COVERAGE_SIGNAL)) {
+ // Coverage handler exited while we were asleep
+ Log.i(LOG_TAG,
+ String.format("Coverage dump detected finished after %dms",
+ System.currentTimeMillis() - start));
+ break;
+ }
+ } else {
+ // Coverage signal handler not yet started or invalid siginfo
+ Thread.sleep(100L);
+ }
+ } catch (InterruptedException e) {
+ // ignored
+ }
+ }
+ }
+
+ /**
+ * Class for reading a process' signal masks from the /proc filesystem. Looks for the
+ * BLOCKED, CAUGHT, IGNORED and PENDING masks from /proc/self/status, each of which is a
+ * 64 bit bitmask with one bit per signal.
+ *
+ * Maintains a map from SignalMaskInfo.Type to the bitmask. The {@code isValid} method
+ * will only return true if all 4 masks were successfully parsed. Provides lookup
+ * methods per signal, e.g. {@code isPending(signum)} which will throw
+ * {@code IllegalStateException} if the current data is not valid.
+ */
+ private static class SignalMaskInfo {
+ private enum Type {
+ BLOCKED("SigBlk"),
+ CAUGHT("SigCgt"),
+ IGNORED("SigIgn"),
+ PENDING("SigPnd");
+ // The tag for this mask in /proc/self/status
+ private final String tag;
+
+ Type(String tag) {
+ this.tag = tag + ":\t";
+ }
+
+ public String getTag() {
+ return tag;
+ }
+
+ public static Map<Type, Long> parseProcinfo(String path) {
+ Map<Type, Long> map = new HashMap<>();
+ try (BufferedReader reader = new BufferedReader(new FileReader(path))) {
+ String line;
+ while ((line = reader.readLine()) != null) {
+ for (Type mask : Type.values()) {
+ long value = mask.tryToParse(line);
+ if (value >= 0) {
+ map.put(mask, value);
+ }
+ }
+ }
+ } catch (NumberFormatException | IOException e) {
+ // Ignored - the map will end up being invalid instead.
+ }
+ return map;
+ }
+
+ private long tryToParse(String line) {
+ if (line.startsWith(tag)) {
+ return Long.valueOf(line.substring(tag.length()), 16);
+ } else {
+ return -1;
+ }
+ }
+ }
+
+ private static final String PROCFS_PATH = "/proc/self/status";
+ private Map<Type, Long> maskMap = null;
+
+ SignalMaskInfo() {
+ refresh();
+ }
+
+ public void refresh() {
+ maskMap = Type.parseProcinfo(PROCFS_PATH);
+ }
+
+ public boolean isValid() {
+ return (maskMap != null && maskMap.size() == Type.values().length);
+ }
+
+ public boolean isCaught(int signal) {
+ return isSignalInMask(signal, Type.CAUGHT);
+ }
+
+ public boolean isBlocked(int signal) {
+ return isSignalInMask(signal, Type.BLOCKED);
+ }
+
+ public boolean isPending(int signal) {
+ return isSignalInMask(signal, Type.PENDING);
+ }
+
+ public boolean isIgnored(int signal) {
+ return isSignalInMask(signal, Type.IGNORED);
+ }
+
+ private void checkValid() {
+ if (!isValid()) {
+ throw new IllegalStateException();
+ }
+ }
+
+ private boolean isSignalInMask(int signal, Type mask) {
+ long bit = 1L << (signal - 1);
+ return (getSignalMask(mask) & bit) != 0;
+ }
+
+ private long getSignalMask(Type mask) {
+ checkValid();
+ Long value = maskMap.get(mask);
+ if (value == null) {
+ throw new IllegalStateException();
+ }
+ return value;
+ }
+ }
+}
\ No newline at end of file
