8334433: jshell.exe runs an executable test.exe on startup

Reviewed-by: jpai

src/jdk.internal.le/share/classes/jdk/internal/org/jline/utils/OSUtils.java

@@ -63,7 +63,7 @@ public class OSUtils {
         String sttyfopt = null;
         String infocmp = null;
         String test = null;
-        String path = System.getenv("PATH");
+        String path = "/usr/bin" + File.pathSeparator + "/bin";//was: System.getenv("PATH");
         if (path != null) {
             String[] paths = path.split(File.pathSeparator);
             for (String p : paths) {

src/jdk.jshell/share/classes/jdk/internal/jshell/tool/ConsoleIOContext.java

@@ -154,7 +154,12 @@ class ConsoleIOContext extends IOContext {
             setupReader = setupReader.andThen(r -> r.option(Option.DISABLE_HIGHLIGHTER, !enableHighlighter));
             input.setInputStream(cmdin);
         } else {
-            terminal = TerminalBuilder.builder().inputStreamWrapper(in -> {
+            //on platforms which are known to be fully supported by
+            //the FFMTerminalProvider, do not permit the ExecTerminalProvider:
+            boolean allowExecTerminal = !OSUtils.IS_WINDOWS &&
+                                        !OSUtils.IS_LINUX &&
+                                        !OSUtils.IS_OSX;
+            terminal = TerminalBuilder.builder().exec(allowExecTerminal).inputStreamWrapper(in -> {
                 input.setInputStream(in);
                 return nonBlockingInput;
             }).nativeSignals(false).build();

test/langtools/jdk/jshell/TerminalNoExecTest.java

@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
+ * 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
+ * @bug 8334433
+ * @summary Verify that when running JShell on platforms that support FFMTerminalProvider,
+ *          no new processes are spawned.
+ * @requires os.family == "windows" | os.family == "mac" | os.family == "linux"
+ * @library /tools/lib
+ * @modules jdk.compiler/com.sun.tools.javac.api
+ *          jdk.compiler/com.sun.tools.javac.main
+ *          jdk.compiler/com.sun.tools.javac.util
+ * @build toolbox.ToolBox toolbox.JavaTask TerminalNoExecTest
+ * @run main TerminalNoExecTest
+ */
+
+import java.io.Writer;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import jdk.jfr.consumer.RecordingStream;
+import jdk.jshell.tool.JavaShellToolBuilder;
+
+import toolbox.ToolBox;
+
+public class TerminalNoExecTest {
+
+    public static void main(String... args) throws Exception {
+        if (args.length > 0) {
+            AtomicBoolean spawnedNewProcess = new AtomicBoolean();
+            try (var rs = new RecordingStream()) {
+                rs.enable("jdk.ProcessStart").withoutThreshold();
+                rs.onEvent(evt -> {
+                    System.err.println("evt: " + evt);
+                    spawnedNewProcess.set(true);
+                });
+                rs.startAsync();
+                JavaShellToolBuilder.builder().run("--execution=local", "--no-startup");
+                rs.stop();
+            }
+            if (spawnedNewProcess.get()) {
+                System.err.println("Spawned a new process!");
+                System.exit(1);
+            }
+            System.exit(0);
+        } else {
+            Path testScript = Paths.get("do-exit");
+            try (Writer w = Files.newBufferedWriter(testScript)) {
+                w.append("/exit\n");
+            }
+
+            ToolBox tb = new ToolBox();
+            Process target =
+                new ProcessBuilder(tb.getJDKTool("java").toString(),
+                                   "-classpath", System.getProperty("java.class.path"),
+                                   TerminalNoExecTest.class.getName(),
+                                   "run-test")
+                        .redirectError(ProcessBuilder.Redirect.INHERIT)
+                        .redirectOutput(ProcessBuilder.Redirect.INHERIT)
+                        .redirectInput(testScript.toFile())
+                        .start();
+
+            target.waitFor();
+
+            int exitCode = target.exitValue();
+
+            if (exitCode != 0) {
+                throw new AssertionError("Incorrect exit value, expected 0, got: " + exitCode);
+            }
+        }
+    }
+
+}