8346378: Cannot use DllMain in libnet for static builds

Reviewed-by: djelinski

Author: magicus

src/java.base/share/native/libnet/net_util.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 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
@@ -63,6 +63,10 @@ DEF_JNI_OnLoad(JavaVM *vm, void *reserved)
         return JNI_EVERSION; /* JNI version not supported */
     }
 
+    if (NET_PlatformInit() != 0) {
+      return JNI_ERR;
+    }
+
     iCls = (*env)->FindClass(env, "java/lang/Boolean");
     CHECK_NULL_RETURN(iCls, JNI_VERSION_1_2);
     mid = (*env)->GetStaticMethodID(env, iCls, "getBoolean", "(Ljava/lang/String;)Z");

src/java.base/share/native/libnet/net_util.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 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
@@ -155,6 +155,8 @@ int NET_IsEqual(jbyte* caddr1, jbyte* caddr2);
 
 int NET_IsZeroAddr(jbyte* caddr);
 
+int NET_PlatformInit();
+
 /* Socket operations
  *
  * These work just like the system calls, except that they may do some

src/java.base/unix/native/libnet/net_util_md.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 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
@@ -50,6 +50,15 @@
 #define IPV6_FLOWINFO_SEND      33
 #endif
 
+/* Perform platform specific initialization.
+ * Returns 0 on success, non-0 on failure */
+int
+NET_PlatformInit()
+{
+    // Not needed on unix
+    return 0;
+}
+
 void
 NET_ThrowByNameWithLastError(JNIEnv *env, const char *name,
                    const char *defaultDetail) {

src/java.base/windows/native/libnet/net_util_md.c

@@ -101,29 +101,21 @@ static struct {
     { WSA_OPERATION_ABORTED,    0,      "Overlapped operation aborted" },
 };
 
-/*
- * Initialize Windows Sockets API support
- */
-BOOL WINAPI
-DllMain(HINSTANCE hinst, DWORD reason, LPVOID reserved)
+static void at_exit_callback(void)
 {
-    WSADATA wsadata;
+    WSACleanup();
+}
 
-    switch (reason) {
-        case DLL_PROCESS_ATTACH:
-            if (WSAStartup(MAKEWORD(2,2), &wsadata) != 0) {
-                return FALSE;
-            }
-            break;
+/* Perform platform specific initialization.
+ * Returns 0 on success, non-0 on failure */
+int
+NET_PlatformInit()
+{
+    WSADATA wsadata;
 
-        case DLL_PROCESS_DETACH:
-            WSACleanup();
-            break;
+    atexit(at_exit_callback);
 
-        default:
-            break;
-    }
-    return TRUE;
+    return WSAStartup(MAKEWORD(2,2), &wsadata);
 }
 
 /*