[GR-71005] Fix Encoding mismatch in JVM_GetTemporaryDirectory on Windows.

pejovica · pejovica · commit bf73c43b4d3c · 2025-10-31T00:55:34.000Z
PullRequest: graal/22472
diff --git a/substratevm/src/com.oracle.svm.native.jvm.windows/src/JvmFuncs.c b/substratevm/src/com.oracle.svm.native.jvm.windows/src/JvmFuncs.c
@@ -248,12 +248,13 @@ JNIEXPORT jobject JNICALL JVM_DoPrivileged(JNIEnv *env, jclass cls, jobject acti
 }
 
 JNIEXPORT jstring JNICALL JVM_GetTemporaryDirectory(JNIEnv *env) {
-    // see os_windows.cpp line 1367
-    static char path_buf[MAX_PATH];
-    if (GetTempPath(MAX_PATH, path_buf) <= 0) {
-        path_buf[0] = '\0';
+    // see os::get_temp_directory() in os_windows.cpp
+    WCHAR path_buf[MAX_PATH + 1];
+    DWORD len = GetTempPathW(MAX_PATH + 1, path_buf);
+    if (len == 0 || len > MAX_PATH + 1) {
+        return (*env)->NewString(env, NULL, 0); // empty on error/overflow
     }
-    return (*env)->NewStringUTF(env, path_buf);
+    return (*env)->NewString(env, path_buf, len);
 }
 
 jboolean VerifyFixClassname(char *utf_name) {

Original file line number	Diff line number	Diff line change
`@@ -248,12 +248,13 @@ JNIEXPORT jobject JNICALL JVM_DoPrivileged(JNIEnv *env, jclass cls, jobject acti`
`248`	`248`	`}`
`249`	`249`
`250`	`250`	`JNIEXPORT jstring JNICALL JVM_GetTemporaryDirectory(JNIEnv *env) {`
`251`		`- // see os_windows.cpp line 1367`
`252`		`- static char path_buf[MAX_PATH];`
`253`		`- if (GetTempPath(MAX_PATH, path_buf) <= 0) {`
`254`		`- path_buf[0] = '\0';`
	`251`	`+ // see os::get_temp_directory() in os_windows.cpp`
	`252`	`+ WCHAR path_buf[MAX_PATH + 1];`
	`253`	`+ DWORD len = GetTempPathW(MAX_PATH + 1, path_buf);`
	`254`	`+ if (len == 0 \|\| len > MAX_PATH + 1) {`
	`255`	`+ return (*env)->NewString(env, NULL, 0); // empty on error/overflow`
`255`	`256`	`}`
`256`		`- return (*env)->NewStringUTF(env, path_buf);`
	`257`	`+ return (*env)->NewString(env, path_buf, len);`
`257`	`258`	`}`
`258`	`259`
`259`	`260`	`jboolean VerifyFixClassname(char *utf_name) {`