8349254: Disable "best-fit" mapping on Windows environment variables

Reviewed-by: jlu, jpai

Author: naotoj

src/java.base/share/native/libjli/args.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2025, 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
@@ -83,6 +83,9 @@ static jboolean relaunch = JNI_FALSE;
  * Prototypes for internal functions.
  */
 static jboolean expand(JLI_List args, const char *str, const char *var_name);
+#ifdef _WIN32
+static char * winGetEnv(const char * var_name);
+#endif
 
 JNIEXPORT void JNICALL
 JLI_InitArgProcessing(jboolean hasJavaArgs, jboolean disableArgFile) {
@@ -465,8 +468,6 @@ int isTerminalOpt(char *arg) {
 
 JNIEXPORT jboolean JNICALL
 JLI_AddArgsFromEnvVar(JLI_List args, const char *var_name) {
-    char *env = getenv(var_name);
-
     if (firstAppArgIndex == 0) {
         // Not 'java', return
         return JNI_FALSE;
@@ -476,12 +477,25 @@ JLI_AddArgsFromEnvVar(JLI_List args, const char *var_name) {
         return JNI_FALSE;
     }
 
-    if (NULL == env) {
-        return JNI_FALSE;
+#ifdef _WIN32
+    char *env = winGetEnv(var_name);
+#else
+    char *env = getenv(var_name);
+#endif
+
+    jboolean ret = JNI_FALSE;
+
+    if (NULL != env) {
+        JLI_ReportMessage(ARG_INFO_ENVVAR, var_name, env);
+        ret = expand(args, env, var_name);
     }
 
-    JLI_ReportMessage(ARG_INFO_ENVVAR, var_name, env);
-    return expand(args, env, var_name);
+#ifdef _WIN32
+    if (NULL != env) {
+        JLI_MemFree(env);
+    }
+#endif
+    return ret;
 }
 
 /*
@@ -583,6 +597,39 @@ static jboolean expand(JLI_List args, const char *str, const char *var_name) {
     return JNI_TRUE;
 }
 
+#ifdef _WIN32
+/*
+ * getenv() without best-fit mapping. The return value is constructed by converting
+ * _wgetenv()'s return encoded in wide char to ANSI code page without best-fit map.
+ */
+static char * winGetEnv(const char * var_name) {
+    char * mbEnvVar = NULL;
+
+    int wcCount = MultiByteToWideChar(CP_ACP, 0, var_name, -1, NULL, 0);
+    if (wcCount > 0) {
+        LPWSTR wcVarName = JLI_MemAlloc(wcCount * sizeof(wchar_t));
+        if (MultiByteToWideChar(CP_ACP, 0, var_name, -1, wcVarName, wcCount) != 0) {
+            LPWSTR wcEnvVar = _wgetenv(wcVarName);
+            if (wcEnvVar != NULL) {
+                int mbSize = WideCharToMultiByte(CP_ACP,
+                    WC_NO_BEST_FIT_CHARS | WC_COMPOSITECHECK | WC_DEFAULTCHAR,
+                    wcEnvVar, -1, NULL, 0, NULL, NULL);
+                if (mbSize > 0) {
+                    mbEnvVar = JLI_MemAlloc(mbSize);
+                    if (WideCharToMultiByte(CP_ACP, WC_NO_BEST_FIT_CHARS | WC_COMPOSITECHECK | WC_DEFAULTCHAR,
+                        wcEnvVar, -1, mbEnvVar, mbSize, NULL, NULL) == 0) {
+                        JLI_MemFree(mbEnvVar);
+                        mbEnvVar = NULL;
+                    }
+                }
+            }
+        }
+        JLI_MemFree(wcVarName);
+    }
+    return mbEnvVar;
+}
+#endif
+
 #ifdef DEBUG_ARGFILE
 /*
  * Stand-alone sanity test, build with following command line

src/java.base/windows/native/libjava/ProcessEnvironment_md.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2025, 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
@@ -28,55 +28,18 @@
 #include "jni_util.h"
 #include <windows.h>
 
-static jstring
-environmentBlock9x(JNIEnv *env)
-{
-    int i;
-    jmethodID String_init_ID;
-    jbyteArray bytes;
-    jbyte *blockA;
-    jclass string_class;
-
-    string_class = JNU_ClassString(env);
-    CHECK_NULL_RETURN(string_class, NULL);
-
-    String_init_ID =
-        (*env)->GetMethodID(env, string_class, "<init>", "([B)V");
-    CHECK_NULL_RETURN(String_init_ID, NULL);
-
-    blockA = (jbyte *) GetEnvironmentStringsA();
-    if (blockA == NULL) {
-        /* Both GetEnvironmentStringsW and GetEnvironmentStringsA
-         * failed.  Out of memory is our best guess.  */
-        JNU_ThrowOutOfMemoryError(env, "GetEnvironmentStrings failed");
-        return NULL;
-    }
-
-    /* Don't search for "\0\0", since an empty environment block may
-       legitimately consist of a single "\0". */
-    for (i = 0; blockA[i];)
-        while (blockA[i++])
-            ;
-
-    if ((bytes = (*env)->NewByteArray(env, i)) == NULL) {
-        FreeEnvironmentStringsA(blockA);
-        return NULL;
-    }
-    (*env)->SetByteArrayRegion(env, bytes, 0, i, blockA);
-    FreeEnvironmentStringsA(blockA);
-    return (*env)->NewObject(env, string_class,
-                             String_init_ID, bytes);
-}
-
 /* Returns a Windows style environment block, discarding final trailing NUL */
 JNIEXPORT jstring JNICALL
 Java_java_lang_ProcessEnvironment_environmentBlock(JNIEnv *env, jclass klass)
 {
     int i;
     jstring envblock;
     jchar *blockW = (jchar *) GetEnvironmentStringsW();
-    if (blockW == NULL)
-        return environmentBlock9x(env);
+    if (blockW == NULL) {
+        /* Out of memory is our best guess. */
+        JNU_ThrowOutOfMemoryError(env, "GetEnvironmentStrings failed");
+        return NULL;
+    }
 
     /* Don't search for "\u0000\u0000", since an empty environment
        block may legitimately consist of a single "\u0000".  */

test/jdk/tools/launcher/DisableBestFitMappingTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2024, 2025, 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
@@ -23,9 +23,10 @@
 
 /*
  * @test
- * @bug 8337506
- * @summary Verify Command Line arguments are not mapped with
- *     "best-fit" mappings on Windows
+ * @bug 8337506 8349254
+ * @summary Verify command line arguments, including ones from
+ *          "JDK_JAVA_OPTIONS" environment variables are not mapped
+ *          with "best-fit" mappings on Windows
  * @requires (os.family == "windows")
  * @library /test/lib
  * @run junit DisableBestFitMappingTest
@@ -34,9 +35,9 @@
 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;
@@ -49,10 +50,12 @@ public class DisableBestFitMappingTest {
             Charset.forName(System.getProperty("native.encoding")).newEncoder();
     private static final String REPLACEMENT =
             NATIVE_ENC.charset().decode(ByteBuffer.wrap(NATIVE_ENC.replacement())).toString();
+    private static final String TEST_ENV_VAR = "JDK_JAVA_OPTIONS";
+    private static final String TEST_PROP_KEY = "testProp";
     private static final int EXIT_SUCCESS = 0;
     private static final int EXIT_FAILURE = -1;
 
-    static Stream<Arguments> CMD_ARGS() {
+    static Stream<Arguments> TEST_ARGS() {
         return Stream.of(
                 Arguments.of("aa\uff02 \uff02bb", "aa" + REPLACEMENT + " " + REPLACEMENT + "bb"),
                 Arguments.of("aa\uff01bb", "aa" + REPLACEMENT + "bb"),
@@ -61,23 +64,41 @@ static Stream<Arguments> CMD_ARGS() {
     }
 
     @ParameterizedTest
-    @MethodSource("CMD_ARGS")
-    void testDisableBestFitMapping(String arg, String expected) throws Exception {
+    @MethodSource("TEST_ARGS")
+    void testCommandLineArgument(String arg, String expected) throws Exception {
         // Only execute if the arg cannot be encoded
         assumeFalse(NATIVE_ENC.canEncode(arg),
                 "native.encoding (%s) can encode the argument '%s'. Test ignored."
                         .formatted(NATIVE_ENC.charset(), arg));
 
-        var result= ProcessTools.executeTestJava(
-                DisableBestFitMappingTest.class.getSimpleName(), arg, expected);
+        var result = ProcessTools.executeTestJava(
+                DisableBestFitMappingTest.class.getSimpleName(), expected, arg);
+        result.asLines().forEach(System.out::println);
+        assertEquals(EXIT_SUCCESS, result.getExitValue(),
+                "Command line argument mapping failed");
+    }
+
+    @ParameterizedTest
+    @MethodSource("TEST_ARGS")
+    void testEnvironmentVariable(String propVal, String expected) throws Exception {
+        // Only execute if the arg from the environment variable cannot be encoded
+        assumeFalse(NATIVE_ENC.canEncode(propVal),
+                "native.encoding (%s) can encode the argument '%s'. Test ignored."
+                        .formatted(NATIVE_ENC.charset(), propVal));
+
+        var pb = ProcessTools.createTestJavaProcessBuilder(
+                DisableBestFitMappingTest.class.getSimpleName(), expected);
+        pb.environment().put(TEST_ENV_VAR, "-D" + TEST_PROP_KEY + "=\"" + propVal + "\"");
+        var result = ProcessTools.executeProcess(pb);
         result.asLines().forEach(System.out::println);
         assertEquals(EXIT_SUCCESS, result.getExitValue(),
-                "Disabling best-fit mapping failed");
+                "Argument from JDK_JAVA_OPTIONS 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);
+        var expected = args[0];
+        var actual = args.length > 1 ? args[1] : System.getProperty(TEST_PROP_KEY);
+        System.out.printf("expected: %s, actual: %s%n", expected, actual);
+        System.exit(expected.equals(actual) ? EXIT_SUCCESS : EXIT_FAILURE);
     }
 }