8337506: Disable "best-fit" mapping on Windows command line

src/java.base/share/native/launcher/main.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1995, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1995, 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
@@ -150,7 +150,25 @@ main(int argc, char **argv)
             }
         }
     }
-    JLI_CmdToArgs(GetCommandLine());
+
+    // Obtain the command line in UTF-16, then convert it to ANSI code page
+    // without the "best-fit" option
+    LPWSTR wcCmdline = GetCommandLineW();
+    int mbSize = WideCharToMultiByte(CP_ACP,
+        WC_NO_BEST_FIT_CHARS | WC_COMPOSITECHECK | WC_DEFAULTCHAR,
+        wcCmdline, -1, NULL, 0, NULL, NULL);
+    // If the call to WideCharToMultiByte() fails, it returns 0, which
+    // will then make the following JLI_MemAlloc() to issue exit(1)
+    LPSTR mbCmdline = JLI_MemAlloc(mbSize);
+    if (WideCharToMultiByte(CP_ACP, WC_NO_BEST_FIT_CHARS | WC_COMPOSITECHECK | WC_DEFAULTCHAR,
+        wcCmdline, -1, mbCmdline, mbSize, NULL, NULL) == 0) {
+        perror("command line encoding conversion failure");
+        exit(1);
+    }
+
+    JLI_CmdToArgs(mbCmdline);
+    JLI_MemFree(mbCmdline);
+
     margc = JLI_GetStdArgc();
     // add one more to mark the end
     margv = (char **)JLI_MemAlloc((margc + 1) * (sizeof(char *)));

test/jdk/tools/launcher/DisableBestFitMappingTest.java

@@ -0,0 +1,84 @@
+/*
+ * 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 8337506
+ * @summary Verify Command Line arguments are not mapped with
+ *     "best-fit" mappings on Windows
+ * @requires (os.family == "windows")
+ * @library /test/lib
+ * @run junit DisableBestFitMappingTest
+ */
+import java.nio.ByteBuffer;
+import java.nio.charset.Charset;
+import java.nio.charset.CharsetEncoder;
+import java.util.stream.Stream;
+import jdk.test.lib.process.ProcessTools;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assumptions.*;
+
+public class DisableBestFitMappingTest {
+    private static final CharsetEncoder NATIVE_ENC =
+            Charset.forName(System.getProperty("file.encoding")).newEncoder();
+    private static final String REPLACEMENT =
+            NATIVE_ENC.charset().decode(ByteBuffer.wrap(NATIVE_ENC.replacement())).toString();
+    private static final int EXIT_SUCCESS = 0;
+    private static final int EXIT_FAILURE = -1;
+
+    static Stream<Arguments> CMD_ARGS() {
+        return Stream.of(
+                Arguments.of("aa\uff02 \uff02bb", "aa" + REPLACEMENT + " " + REPLACEMENT + "bb"),
+                Arguments.of("aa\uff01bb", "aa" + REPLACEMENT + "bb"),
+                Arguments.of("aa\u221ebb", "aa" + REPLACEMENT + "bb")
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("CMD_ARGS")
+    void testDisableBestFitMapping(String arg, String expected) throws Exception {
+        // Only execute if the arg cannot be encoded
+        assumeFalse(NATIVE_ENC.canEncode(arg),
+                    String.format(
+                        "native.encoding (%s) can encode the argument '%s'. Test ignored.",
+                        NATIVE_ENC.charset(), arg));
+
+        var result= ProcessTools.executeTestJava(
+                DisableBestFitMappingTest.class.getSimpleName(), arg, expected);
+        result.asLines().forEach(System.out::println);
+        assertEquals(EXIT_SUCCESS, result.getExitValue(),
+                "Disabling best-fit mapping failed");
+    }
+
+    public static void main(String... args) {
+        System.out.println(args[0]);
+        System.out.println(args[1]);
+        System.exit(args[0].equals(args[1]) ? EXIT_SUCCESS : EXIT_FAILURE);
+    }
+}