Fix AFSocketAddress serialization

kohlschuetter · kohlschuetter · commit a45bb34a0574 · 2023-01-27T19:21:27.000+01:00
Since AFSocketAddress extends SocketAddress, it must support
serialization.

Unfortunately, there were two members that aren't serializable.

Fix serialization to keep everyone happy.
diff --git a/junixsocket-common/src/main/java/org/newsclub/net/unix/AFSocketAddress.java b/junixsocket-common/src/main/java/org/newsclub/net/unix/AFSocketAddress.java
@@ -21,6 +21,8 @@
 import java.io.FileDescriptor;
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
 import java.net.DatagramSocket;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
@@ -87,12 +89,13 @@ protected ByteBuffer initialValue() {
   /**
    * The system-native representation of this address, or {@code null}.
    */
-  private final ByteBuffer nativeAddress;
+  @SuppressWarnings("PMD.ImmutableField")
+  private transient ByteBuffer nativeAddress;
 
   /**
    * The address family.
    */
-  private final AFAddressFamily<?> addressFamily;
+  private transient AFAddressFamily<?> addressFamily;
 
   /**
    * Creates a new socket address.
@@ -643,12 +646,13 @@ public URI toURI(String scheme, URI template) throws IOException {
    * address type is not natively supported by this platform.
    *
    * This call is mostly suited for debugging purposes. The resulting string is specific to the
-   * platform the code is executed on, and thus may be different among platforms (or {@code null}).
+   * platform the code is executed on, and thus may be different among platforms.
    *
    * @param socketType The socket type, or {@code null} to omit from string.
    * @param socketProtocol The socket protocol, or {@code null} to omit from string.
    * @return The string (such as 1:0:x2f746d702f796f).
-   * @throws IOException on error.
+   * @throws IOException on error (a {@link SocketException} is thrown if the native address cannot
+   *           be accessed).
    */
   public @Nullable @SuppressWarnings("PMD.NPathComplexity") String toSocatAddressString(
       AFSocketType socketType, AFSocketProtocol socketProtocol) throws IOException {
@@ -703,4 +707,28 @@ public URI toURI(String scheme, URI template) throws IOException {
   public boolean covers(AFSocketAddress other) {
     return this.equals(other);
   }
+
+  /**
+   * Custom serialization: Reference {@link AFAddressFamily} instance by identifier string.
+   * 
+   * @param in The {@link ObjectInputStream}.
+   * @throws ClassNotFoundException on error.
+   * @throws IOException on error.
+   */
+  private void readObject(ObjectInputStream in) throws ClassNotFoundException, IOException {
+    in.defaultReadObject();
+    this.addressFamily = Objects.requireNonNull(AFAddressFamily.getAddressFamily(in.readUTF()),
+        "address family");
+  }
+
+  /**
+   * Custom serialization: Reference {@link AFAddressFamily} instance by identifier string.
+   * 
+   * @param out The {@link ObjectOutputStream}.
+   * @throws IOException on error.
+   */
+  private void writeObject(ObjectOutputStream out) throws IOException {
+    out.defaultWriteObject();
+    out.writeUTF(addressFamily.getJuxString());
+  }
 }
diff --git a/junixsocket-common/src/test/java/org/newsclub/net/unix/AFUNIXSocketAddressTest.java b/junixsocket-common/src/test/java/org/newsclub/net/unix/AFUNIXSocketAddressTest.java
@@ -22,7 +22,11 @@
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
 import java.io.File;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
 import java.net.URI;
 import java.util.Arrays;
 
@@ -133,4 +137,22 @@ public void testAbstractNamespace() throws Exception {
     assertNotNull(AFUNIXSocketAddress.inAbstractNamespace("test"));
     assertNotNull(AFUNIXSocketAddress.inAbstractNamespace("test", 1234));
   }
+
+  @Test
+  public void testSerialize() throws Exception {
+    try (ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        ObjectOutputStream oos = new ObjectOutputStream(bos)) {
+
+      AFUNIXSocketAddress addr = AFUNIXSocketAddress.of(URI.create("file:/tmp/yo"));
+      oos.writeObject(addr);
+      oos.flush();
+
+      try (ObjectInputStream oin = new ObjectInputStream(new ByteArrayInputStream(bos
+          .toByteArray()))) {
+        AFUNIXSocketAddress addr2 = (AFUNIXSocketAddress) oin.readObject();
+        assertEquals(addr, addr2);
+        assertEquals(addr.getAddressFamily(), addr2.getAddressFamily());
+      }
+    }
+  }
 }
