Add bootstrap checks (#1593)

* Add bootstrap check for disabled bytecode verification

Co-authored-by: Sylvain Juge <[email protected]>

Author: felixbarny

CHANGELOG.asciidoc

@@ -46,6 +46,8 @@ any further configuration. Supports log4j1, log4j2 and Logback. {pull}1261[#1261
 * Add support to Spring AMQP - {pull}1657[#1657]
 * Adds the ability to automatically configure usage of the OpenTracing bridge in systems using ServiceLoader - {pull}1708[#1708]
 * Update to async-profiler 1.8.5
+* Add a warning on startup when `-Xverify:none` or `-noverify` flags are set as this can lead to crashes that are very difficult to debug - {pull}1593[#1593]
+  In an upcoming version, the agent will not start when these flags are set, unless the system property `elastic.apm.disable_bootstrap_checks` is set to true.
 
 [float]
 ===== Bug fixes

apm-agent-core/src/main/java/co/elastic/apm/agent/bci/IndyBootstrap.java

@@ -27,6 +27,7 @@
 import co.elastic.apm.agent.bci.classloading.ExternalPluginClassLoader;
 import co.elastic.apm.agent.bci.classloading.IndyPluginClassLoader;
 import co.elastic.apm.agent.bci.classloading.LookupExposer;
+import co.elastic.apm.agent.premain.JavaVersionBootstrapCheck;
 import co.elastic.apm.agent.sdk.state.GlobalState;
 import co.elastic.apm.agent.premain.JvmRuntimeInfo;
 import co.elastic.apm.agent.util.PackageScanner;
@@ -156,7 +157,7 @@
  *     <li>
  *         The {@code INVOKEDYNAMIC} support of early Java 7 versions is not reliable.
  *         That's why we disable the agent on them.
- *         See also {@link JvmRuntimeInfo#isJavaVersionSupported}
+ *         See also {@link JavaVersionBootstrapCheck}
  *     </li>
  *     <li>
  *         There are some things to watch out for when writing plugins,
@@ -224,7 +225,7 @@ private static Class<?> initIndyBootstrap(final Logger logger) throws Exception
             indyBootstrapDispatcherClass = Class.forName(INDY_BOOTSTRAP_CLASS_NAME, false, null);
         }
 
-        if (JvmRuntimeInfo.getMajorVersion() >= 9 && JvmRuntimeInfo.isJ9VM()) {
+        if (JvmRuntimeInfo.ofCurrentVM().getMajorVersion() >= 9 && JvmRuntimeInfo.ofCurrentVM().isJ9VM()) {
             try {
                 logger.info("Overriding IndyBootstrapDispatcher class's module to java.base module. This is required in J9 VMs.");
                 setJavaBaseModule(indyBootstrapDispatcherClass);

apm-agent-core/src/main/java/co/elastic/apm/agent/impl/ElasticApmTracer.java

@@ -526,7 +526,7 @@ public synchronized void start(boolean premain) {
     }
 
     private boolean shouldDelayOnPremain() {
-        return JvmRuntimeInfo.getMajorVersion() <= 8 &&
+        return JvmRuntimeInfo.ofCurrentVM().getMajorVersion() <= 8 &&
             ClassLoader.getSystemClassLoader().getResource("org/apache/catalina/startup/Bootstrap.class") != null;
     }
 

apm-agent-core/src/test/java/co/elastic/apm/agent/bci/VerifyNoneBootstrapCheckTest.java

@@ -0,0 +1,70 @@
+/*-
+ * #%L
+ * Elastic APM Java agent
+ * %%
+ * Copyright (C) 2018 - 2020 Elastic and contributors
+ * %%
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you 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.
+ * #L%
+ */
+package co.elastic.apm.agent.bci;
+
+import co.elastic.apm.agent.premain.BootstrapCheck;
+import co.elastic.apm.agent.premain.VerifyNoneBootstrapCheck;
+import org.junit.jupiter.api.Test;
+
+import java.lang.management.RuntimeMXBean;
+import java.util.Collections;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+class VerifyNoneBootstrapCheckTest {
+
+    private final BootstrapCheck.BootstrapCheckResult result = new BootstrapCheck.BootstrapCheckResult();
+
+    @Test
+    void testNoverify() {
+        RuntimeMXBean bean = mock(RuntimeMXBean.class);
+        when(bean.getInputArguments()).thenReturn(Collections.singletonList("-noverify"));
+        VerifyNoneBootstrapCheck check = new VerifyNoneBootstrapCheck(bean);
+        check.doBootstrapCheck(result);
+        assertThat(result.hasWarnings()).isTrue();
+        assertThat(result.hasErrors()).isFalse();
+    }
+
+    @Test
+    void testVerifyNone() {
+        RuntimeMXBean bean = mock(RuntimeMXBean.class);
+        when(bean.getInputArguments()).thenReturn(Collections.singletonList("-Xverify:none"));
+        VerifyNoneBootstrapCheck check = new VerifyNoneBootstrapCheck(bean);
+        check.doBootstrapCheck(result);
+        assertThat(result.hasWarnings()).isTrue();
+        assertThat(result.hasErrors()).isFalse();
+    }
+
+    @Test
+    void testVerifyAll() {
+        RuntimeMXBean bean = mock(RuntimeMXBean.class);
+        when(bean.getInputArguments()).thenReturn(Collections.singletonList("-Xverify:all"));
+        VerifyNoneBootstrapCheck check = new VerifyNoneBootstrapCheck(bean);
+        check.doBootstrapCheck(result);
+        assertThat(result.isEmpty()).isTrue();
+    }
+}

apm-agent-plugins/apm-jdk-httpclient-plugin/src/main/java/co/elastic/apm/agent/httpclient/HttpClientInstrumentation.java

@@ -46,7 +46,7 @@ public class HttpClientInstrumentation extends AbstractHttpClientInstrumentation
 
     @Override
     public ElementMatcher<? super NamedElement> getTypeMatcherPreFilter() {
-        return new BooleanMatcher<>(JvmRuntimeInfo.getMajorVersion() >= 11).and(nameContains("HttpClient"));
+        return new BooleanMatcher<>(JvmRuntimeInfo.ofCurrentVM().getMajorVersion() >= 11).and(nameContains("HttpClient"));
     }
 
     @Override

apm-agent-premain/src/main/java/co/elastic/apm/agent/premain/AgentMain.java

@@ -75,30 +75,8 @@ public synchronized static void init(String agentArguments, Instrumentation inst
             return;
         }
 
-        if (!JvmRuntimeInfo.isJavaVersionSupported()) {
-            // Gracefully abort agent startup is better than unexpected failure down the road when we known a given JVM
-            // version is not supported. Agent might trigger known JVM bugs causing JVM crashes, notably on early Java 8
-            // versions (but fixed in later versions), given those versions are obsolete and agent can't have workarounds
-            // for JVM internals, there is no other option but to use an up-to-date JVM instead.
-
-            String msgTemplate;
-
-            boolean doDisable;
-            if (Boolean.parseBoolean(System.getProperty("elastic.apm.disable_bootstrap_checks"))) {
-                // safety check disabled, warn end user that it might
-                doDisable = false;
-                msgTemplate = "WARNING : JVM version unknown or not supported, safety check disabled - %s %s %s";
-            } else {
-                doDisable = true;
-                msgTemplate = "Failed to start agent - JVM version not supported: %s %s %s.\nTo override Java version verification, set the 'elastic.apm.disable_bootstrap_checks' System property to 'true'.";
-            }
-
-            System.err.println(String.format(msgTemplate,
-                JvmRuntimeInfo.getJavaVersion(), JvmRuntimeInfo.getJavaVmName(), JvmRuntimeInfo.getJavaVmVersion()));
-
-            if (doDisable) {
-                return;
-            }
+        if (!BootstrapChecks.defaults().isPassing()) {
+            return;
         }
 
         // workaround for classloader deadlock https://bugs.openjdk.java.net/browse/JDK-8194653
@@ -130,12 +108,13 @@ public synchronized static void init(String agentArguments, Instrumentation inst
      * @return {@code true} for any Java 7 and early Java 8 HotSpot JVMs, {@code false} for all others
      */
     static boolean shouldDelayOnPremain() {
-        int majorVersion = JvmRuntimeInfo.getMajorVersion();
+        JvmRuntimeInfo runtimeInfo = JvmRuntimeInfo.ofCurrentVM();
+        int majorVersion = runtimeInfo.getMajorVersion();
         return
             (majorVersion == 7) ||
             // In case bootstrap checks were disabled
-            (majorVersion == 8 && JvmRuntimeInfo.isHpUx() && JvmRuntimeInfo.getUpdateVersion() < 2) ||
-            (majorVersion == 8 && JvmRuntimeInfo.isHotSpot() && JvmRuntimeInfo.getUpdateVersion() < 40);
+            (majorVersion == 8 && runtimeInfo.isHotSpot() && runtimeInfo.getUpdateVersion() < 2) ||
+            (majorVersion == 8 && runtimeInfo.isHotSpot() && runtimeInfo.getUpdateVersion() < 40);
     }
 
     private static void delayAndInitAgentAsync(final String agentArguments, final Instrumentation instrumentation,

apm-agent-premain/src/main/java/co/elastic/apm/agent/premain/BootstrapCheck.java

@@ -0,0 +1,75 @@
+/*-
+ * #%L
+ * Elastic APM Java agent
+ * %%
+ * Copyright (C) 2018 - 2020 Elastic and contributors
+ * %%
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you 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.
+ * #L%
+ */
+package co.elastic.apm.agent.premain;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A check that gets executed when the agent starts up.
+ * If any check fails, the agent won't start unless the {@code elastic.apm.disable_bootstrap_checks} system property is set to true.
+ */
+public interface BootstrapCheck {
+
+    /**
+     * Performs the bootstrap check.
+     *
+     * @param result Add an error message to avoid the agent from starting up.
+     */
+    void doBootstrapCheck(BootstrapCheckResult result);
+
+    class BootstrapCheckResult {
+        private final List<String> errors = new ArrayList<>();
+        private final List<String> warnings = new ArrayList<>();
+
+        void addError(String message) {
+            errors.add(message);
+        }
+
+        void addWarn(String message) {
+            warnings.add(message);
+        }
+
+        public List<String> getErrors() {
+            return errors;
+        }
+
+        public List<String> getWarnings() {
+            return warnings;
+        }
+
+        public boolean isEmpty() {
+            return warnings.isEmpty() && errors.isEmpty();
+        }
+
+        public boolean hasWarnings() {
+            return !warnings.isEmpty();
+        }
+
+        public boolean hasErrors() {
+            return !errors.isEmpty();
+        }
+    }
+}

apm-agent-premain/src/main/java/co/elastic/apm/agent/premain/BootstrapChecks.java

@@ -0,0 +1,81 @@
+/*-
+ * #%L
+ * Elastic APM Java agent
+ * %%
+ * Copyright (C) 2018 - 2020 Elastic and contributors
+ * %%
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you 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.
+ * #L%
+ */
+package co.elastic.apm.agent.premain;
+
+import java.lang.management.ManagementFactory;
+import java.util.Arrays;
+import java.util.List;
+
+class BootstrapChecks {
+
+    private final List<BootstrapCheck> bootstrapChecks;
+    private final boolean bootstrapChecksEnabled;
+
+    BootstrapChecks(boolean bootstrapChecksEnabled, BootstrapCheck... bootstrapChecks) {
+        this.bootstrapChecks = Arrays.asList(bootstrapChecks);
+        this.bootstrapChecksEnabled = bootstrapChecksEnabled;
+    }
+
+    static BootstrapChecks defaults() {
+        return new BootstrapChecks(!Boolean.parseBoolean(System.getProperty("elastic.apm.disable_bootstrap_checks")),
+            new JavaVersionBootstrapCheck(JvmRuntimeInfo.ofCurrentVM()), new VerifyNoneBootstrapCheck(ManagementFactory.getRuntimeMXBean()));
+    }
+
+    /**
+     * Returns {@code true} if the current VM passes the {@linkplain BootstrapChecks#defaults default bootstrap checks}
+     * or if bootstrap checks are disabled.
+     */
+    boolean isPassing() {
+        BootstrapCheck.BootstrapCheckResult result = new BootstrapCheck.BootstrapCheckResult();
+        for (BootstrapCheck check : bootstrapChecks) {
+            check.doBootstrapCheck(result);
+        }
+
+        if (result.isEmpty()) {
+            return true;
+        }
+        boolean isPassing = true;
+        if (result.hasErrors()) {
+            if (bootstrapChecksEnabled) {
+                isPassing = false;
+                System.err.println("ERROR - Failed to start agent because of failing bootstrap checks.");
+                System.err.println("To override Java version verification, set the 'elastic.apm.disable_bootstrap_checks' System property to 'true'.");
+            } else {
+                System.err.println("WARNING - Bootstrap checks have failed. The agent will still start because bootstrap check have been disabled.");
+            }
+            System.err.println("Note that we can not offer support for issues related to disabled bootstrap checks.");
+            for (String msg : result.getErrors()) {
+                System.err.println(msg);
+            }
+        }
+        if (result.hasWarnings()) {
+            for (String msg : result.getWarnings()) {
+                System.err.println(msg);
+            }
+        }
+        return isPassing;
+    }
+
+}