Introduce velocity.natives-tmpdir property for properly handling noexec /tmp

native/src/main/java/com/velocitypowered/natives/util/Natives.java

@@ -13,6 +13,7 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.nio.file.StandardCopyOption;
 
 public class Natives {
@@ -24,12 +25,12 @@ public class Natives {
   private static Runnable copyAndLoadNative(String path) {
     return () -> {
       try {
-        Path tempFile = Files.createTempFile("native-", path.substring(path.lastIndexOf('.')));
         InputStream nativeLib = Natives.class.getResourceAsStream(path);
         if (nativeLib == null) {
           throw new IllegalStateException("Native library " + path + " not found.");
         }
 
+        Path tempFile = createTemporaryNativeFilename(path.substring(path.lastIndexOf('.')));
         Files.copy(nativeLib, tempFile, StandardCopyOption.REPLACE_EXISTING);
         Runtime.getRuntime().addShutdownHook(new Thread(() -> {
           try {
@@ -50,6 +51,15 @@ public class Natives {
     };
   }
 
+  private static Path createTemporaryNativeFilename(String ext) throws IOException {
+    String temporaryFolderPath = System.getProperty("velocity.natives-tmpdir");
+    if (temporaryFolderPath != null) {
+      return Files.createTempFile(Paths.get(temporaryFolderPath), "native-", ext);
+    } else {
+      return Files.createTempFile("native-", ext);
+    }
+  }
+
   public static final NativeCodeLoader<VelocityCompressorFactory> compress = new NativeCodeLoader<>(
       ImmutableList.of(
           new NativeCodeLoader.Variant<>(NativeConstraints.MACOS,

proxy/src/main/java/com/velocitypowered/proxy/Velocity.java

@@ -23,6 +23,12 @@ public class Velocity {
     if (System.getProperty("io.netty.allocator.maxOrder") == null) {
       System.setProperty("io.netty.allocator.maxOrder", "9");
     }
+
+    // If Velocity's natives are being extracted to a different temporary directory, make sure the
+    // Netty natives are extracted there as well
+    if (System.getProperty("velocity.natives-tmpdir") != null) {
+      System.setProperty("io.netty.native.workdir", System.getProperty("velocity.natives-tmpdir"));
+    }
   }
 
   /**