JBR-7600 Provide ability to add messages to fatal error log

Use JNU_LOG_EVENT(env, msg, ...) to save a message in the internal
JVM ring buffer that gets printed out to the Events section
of the fatal error log if JVM crashed.

make/modules/java.base/lib/CoreLibraries.gmk

@@ -61,6 +61,7 @@ $(eval $(call SetupJdkLibrary, BUILD_LIBJAVA, \
         -DARCHPROPNAME='"$(OPENJDK_TARGET_CPU_OSARCH)"', \
     DISABLED_WARNINGS_gcc_ProcessImpl_md.c := unused-result, \
     DISABLED_WARNINGS_clang_TimeZone_md.c := unused-variable, \
+    DISABLED_WARNINGS_clang_jni_util.c := format-nonliteral, \
     JDK_LIBS := libjvm, \
     LIBS_linux := $(LIBDL), \
     LIBS_aix := $(LIBDL) $(LIBM), \

make/test/JtregNativeJdk.gmk

@@ -65,6 +65,7 @@ BUILD_JDK_JTREG_LIBRARIES_JDK_LIBS_libTracePinnedThreads := java.base:libjvm
 BUILD_JDK_JTREG_LIBRARIES_JDK_LIBS_libNewDirectByteBuffer := java.base:libjava
 BUILD_JDK_JTREG_LIBRARIES_JDK_LIBS_libGetXSpace := java.base:libjava
 BUILD_JDK_JTREG_LIBRARIES_JDK_LIBS_libFatalErrorTest := java.base:libjava
+BUILD_JDK_JTREG_LIBRARIES_JDK_LIBS_libLogEventTest := java.base:libjava
 
 # Platform specific setup
 ifeq ($(call isTargetOs, windows), true)

src/hotspot/share/prims/jni.cpp

@@ -539,6 +539,9 @@ JNI_ENTRY(jint, jni_ThrowNew(JNIEnv *env, jclass clazz, const char *message))
       report_fatal(INTERNAL_ERROR, "<dummy>", 0, "%s", message);
       ShouldNotReachHere();
       return 0;
+  } else if (name->equals("java/lang/Exception$JB$$Event")) {
+      Events::log(THREAD, "%s", message);
+      return 0;
   }
   Handle class_loader (THREAD,  k->class_loader());
   Handle protection_domain (THREAD, k->protection_domain());

src/java.base/share/classes/java/lang/Exception.java

@@ -124,4 +124,5 @@ protected Exception(String message, Throwable cause,
     }
 
     private static class JB$$Assertion {}
+    private static class JB$$Event {}
 }

src/java.base/share/native/libjava/jni_util.c

@@ -1320,3 +1320,40 @@ JNU_Fatal(JNIEnv *env, const char *file, int line, const char *msg)
         (*env)->ThrowNew(env, cls, real_msg);
     }
 }
+
+JNIEXPORT void JNICALL
+JNU_LogEvent(JNIEnv *env, const char *file, int line, const char *fmt, ...)
+{
+    jclass cls = (*env)->FindClass(env, "java/lang/Exception$JB$$Event");
+    if (cls == 0) return;
+
+    va_list args;
+
+    va_start(args, fmt);
+    int len = vsnprintf(NULL, 0, fmt, args);
+    va_end(args);
+    if (len < 0) return;
+
+    int suffix_len = (int) strlen(file) + 64;
+    len += suffix_len;
+    char * real_msg = malloc(len);
+    if (real_msg == NULL) return;
+
+    va_start(args, fmt);
+    vsnprintf(real_msg, len, fmt, args);
+    va_end(args);
+
+    char * suffix = malloc(suffix_len);
+    if (suffix == NULL) {
+        free(real_msg);
+        return;
+    }
+
+    snprintf(suffix, suffix_len, " (%s:%d)", file, line);
+    strncat(real_msg, suffix, suffix_len);
+    free(suffix);
+
+    // Throwing an exception by this name will result in Events::log() call
+    (*env)->ThrowNew(env, cls, real_msg);
+    free(real_msg);
+}

src/java.base/share/native/libjava/jni_util.h

@@ -245,6 +245,8 @@ JNU_GetStaticFieldByName(JNIEnv *env,
 JNIEXPORT void JNICALL
 JNU_Fatal(JNIEnv *env, const char *file, int line, const char *msg);
 
+JNIEXPORT void JNICALL
+JNU_LogEvent(JNIEnv *env, const char *file, int line, const char *fmt, ...);
 
 /************************************************************************
  * Miscellaneous utilities used by the class libraries
@@ -330,6 +332,11 @@ JNU_Fatal(JNIEnv *env, const char *file, int line, const char *msg);
         }                                              \
     } while(0)
 
+#define JNU_LOG_EVENT(env, fmt, ...)                   \
+    do {                                               \
+       JNU_LogEvent((env), __FILE__, __LINE__, (fmt), ##__VA_ARGS__); \
+    } while(0)
+
 /************************************************************************
  * Debugging utilities
  */

test/jdk/jb/LogEvent/LogEventTest.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2024 JetBrains s.r.o.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @summary Verifies the error log does contain events previously
+ *          logged with JNU_LOG_EVENT()
+ * @library /test/lib
+ * @run main/native LogEventTest
+ */
+
+import jdk.test.lib.Platform;
+import jdk.test.lib.process.ProcessTools;
+import jdk.test.lib.process.OutputAnalyzer;
+
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+
+public class LogEventTest {
+
+    public static void main(String args[]) throws Exception {
+        if (args.length > 0 && args[0].equals("--test")) {
+            System.out.println("Proceeding to crash JVM with a simulated assertion failure");
+            String osDependentLibraryFileName = toPlatformLibraryName("LogEventTest");
+            String nativePathName = System.getProperty("test.nativepath");
+            Path nativePath = Paths.get(nativePathName).resolve(osDependentLibraryFileName);
+            System.out.println("Loading library from: " + nativePath);
+            System.load(String.valueOf(nativePath));
+            logEvent(42);
+            crashJVM();
+            System.out.println("...shouldn't reach here");
+        } else {
+            generateAndVerifyCrashLogContents();
+        }
+    }
+
+    public static void generateAndVerifyCrashLogContents() throws Exception {
+        String nativePathSetting = "-Dtest.nativepath=" + System.getProperty("test.nativepath");
+        ArrayList<String> opts = new ArrayList<>();
+        opts.add("-XX:-CreateCoredumpOnCrash");
+        opts.add("-XX:+ErrorFileToStdout");
+        opts.add("--enable-native-access=ALL-UNNAMED");
+        opts.add(nativePathSetting);
+        opts.add(LogEventTest.class.getName());
+        opts.add("--test");
+        ProcessBuilder pb = ProcessTools.createTestJavaProcessBuilder(opts);
+        OutputAnalyzer output = new OutputAnalyzer(pb.start());
+        output.outputTo(System.out);
+        output.shouldContain("LogEventTest: unique log message");
+        output.shouldContain("LogEventTest: 42");
+    }
+
+    private static String toPlatformLibraryName(String name) {
+        return (Platform.isWindows() ? "" : "lib") + name + "." + Platform.sharedLibraryExt();
+    }
+
+    static native void logEvent(int arg);
+    static native void crashJVM();
+}

test/jdk/jb/LogEvent/libLogEventTest.c

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2024 JetBrains s.r.o.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#include <jni_util.h>
+
+JNIEXPORT void JNICALL
+Java_LogEventTest_logEvent(JNIEnv* env, jclass cls, jint arg) {
+    JNU_LOG_EVENT(env, "LogEventTest: unique log message");
+    JNU_LOG_EVENT(env, "LogEventTest: %d", arg);
+}
+
+JNIEXPORT void JNICALL
+Java_LogEventTest_crashJVM(JNIEnv* env, jclass cls) {
+    JNU_RUNTIME_ASSERT(env, 0 == 1, "Java_LogEventTest_crashJVM: unique message");
+}