common: Allow ServerSocketChannel.bind to null/temp address if possible

kohlschuetter · kohlschuetter · commit a690d3d94267 · 2024-07-07T16:02:48.000+02:00
JEP380 allows binding to null address, which creates a temporary address
with a /tmp/socket_NNNNNNN address.

For junixsocket AF_UNIX sockets, use a regular temporary address in this
case.
diff --git a/junixsocket-common/src/main/java/org/newsclub/net/unix/AFAddressFamily.java b/junixsocket-common/src/main/java/org/newsclub/net/unix/AFAddressFamily.java
@@ -19,6 +19,7 @@
 
 import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
+import java.net.SocketAddress;
 import java.net.SocketException;
 import java.net.URI;
 import java.nio.channels.ServerSocketChannel;
@@ -367,4 +368,14 @@ public synchronized SelectorProvider getSelectorProvider() {
     }
     return selectorProvider;
   }
+
+  /**
+   * Returns an appropriate SocketAddress to be used when calling bind with a null argument.
+   *
+   * @return The new socket address, or {@code null}.
+   * @throws IOException on error.
+   */
+  public SocketAddress nullBindAddress() throws IOException {
+    return addressConfig.nullBindAddress();
+  }
 }
diff --git a/junixsocket-common/src/main/java/org/newsclub/net/unix/AFServerSocket.java b/junixsocket-common/src/main/java/org/newsclub/net/unix/AFServerSocket.java
@@ -240,6 +240,11 @@ public final AFServerSocket<A> forceBindAddress(SocketAddress endpoint) {
     });
   }
 
+  @Override
+  public final void bind(SocketAddress endpoint) throws IOException {
+    bind(endpoint, 50);
+  }
+
   @SuppressWarnings("unchecked")
   @Override
   public final void bind(SocketAddress endpoint, int backlog) throws IOException {
@@ -550,11 +555,6 @@ public final AFServerSocket<A> bindHook(SocketAddressFilter hook) {
     return this;
   }
 
-  @Override
-  public void bind(SocketAddress endpoint) throws IOException {
-    bind(endpoint, 50);
-  }
-
   @Override
   public InetAddress getInetAddress() {
     if (!isBound()) {
diff --git a/junixsocket-common/src/main/java/org/newsclub/net/unix/AFSocketAddressConfig.java b/junixsocket-common/src/main/java/org/newsclub/net/unix/AFSocketAddressConfig.java
@@ -17,6 +17,8 @@
  */
 package org.newsclub.net.unix;
 
+import java.io.IOException;
+import java.net.SocketAddress;
 import java.net.SocketException;
 import java.net.URI;
 import java.util.Set;
@@ -70,4 +72,14 @@ protected AFSocketAddressConfig() {
    * @return The set of supported URI schemes.
    */
   protected abstract Set<String> uriSchemes();
+
+  /**
+   * Returns an appropriate SocketAddress to be used when calling bind with a null argument.
+   *
+   * @return The new socket address, or {@code null}.
+   * @throws IOException on error.
+   */
+  protected SocketAddress nullBindAddress() throws IOException {
+    return null;
+  }
 }
diff --git a/junixsocket-common/src/main/java/org/newsclub/net/unix/AFSocketImpl.java b/junixsocket-common/src/main/java/org/newsclub/net/unix/AFSocketImpl.java
@@ -386,7 +386,10 @@ protected final int available() throws IOException {
 
   final void bind(SocketAddress addr, int options) throws IOException {
     if (addr == null) {
-      throw new IllegalArgumentException("Cannot bind to null address");
+      addr = addressFamily.nullBindAddress();
+      if (addr == null) {
+        throw new UnsupportedOperationException("Cannot bind to null address");
+      }
     }
 
     if (addr == AFSocketAddress.INTERNAL_DUMMY_BIND) { // NOPMD
diff --git a/junixsocket-common/src/main/java/org/newsclub/net/unix/AFUNIXSocketAddress.java b/junixsocket-common/src/main/java/org/newsclub/net/unix/AFUNIXSocketAddress.java
@@ -81,6 +81,11 @@ protected String selectorProviderClassname() {
             protected Set<String> uriSchemes() {
               return new HashSet<>(Arrays.asList("unix", "http+unix", "https+unix"));
             }
+
+            @Override
+            protected SocketAddress nullBindAddress() throws IOException {
+              return AFUNIXSocketAddress.ofNewTempFile();
+            }
           });
 
   private AFUNIXSocketAddress(int port, final byte[] socketAddress, Lease<ByteBuffer> nativeAddress)
diff --git a/junixsocket-common/src/test/java/org/newsclub/net/unix/ServerSocketTest.java b/junixsocket-common/src/test/java/org/newsclub/net/unix/ServerSocketTest.java
@@ -80,10 +80,12 @@ public void close() throws IOException {
   public void testBindBadArguments() throws Exception {
     try (ServerSocket sock = newServerSocket()) {
       assertFalse(sock.isBound());
-      assertThrows(IllegalArgumentException.class, () -> {
+
+      try {
         sock.bind(null);
-      });
-      assertFalse(sock.isBound());
+      } catch (UnsupportedOperationException e) {
+        assertFalse(sock.isBound());
+      }
     }
     try (ServerSocket sock = newServerSocket()) {
       assertFalse(sock.isBound());
diff --git a/junixsocket-common/src/test/java/org/newsclub/net/unix/SocketChannelTest.java b/junixsocket-common/src/test/java/org/newsclub/net/unix/SocketChannelTest.java
@@ -19,11 +19,13 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
 import java.io.IOException;
+import java.net.ServerSocket;
 import java.net.SocketAddress;
 import java.net.SocketException;
 import java.net.SocketTimeoutException;
@@ -432,4 +434,49 @@ public void testAcceptNotBoundYet() throws Exception {
     ServerSocketChannel sc = newServerSocketChannel();
     assertThrows(NotYetBoundException.class, sc::accept);
   }
+
+  protected boolean mayTestBindNullThrowUnsupportedOperationException() {
+    return true;
+  }
+
+  protected boolean mayTestBindNullHaveNullLocalSocketAddress() {
+    return true;
+  }
+
+  protected void cleanupTestBindNull(ServerSocketChannel sc, SocketAddress addr) throws Exception {
+  }
+
+  protected ServerSocket socketIfPossible(ServerSocketChannel channel) {
+    try {
+      return channel.socket();
+    } catch (UnsupportedOperationException e) {
+      return null;
+    }
+  }
+
+  @Test
+  public void testBindNull() throws Exception {
+    try (ServerSocketChannel sc = newServerSocketChannel()) {
+      ServerSocket s = socketIfPossible(sc);
+      assertTrue(s == null || !s.isBound());
+      try {
+        sc.bind(null);
+      } catch (UnsupportedOperationException e) {
+        if (mayTestBindNullThrowUnsupportedOperationException()) {
+          // OK
+          return;
+        } else {
+          throw e;
+        }
+      }
+      assertTrue(s == null || s.isBound());
+
+      SocketAddress addr = sc.getLocalAddress();
+      if (!mayTestBindNullHaveNullLocalSocketAddress()) {
+        assertNotNull(addr);
+      }
+
+      cleanupTestBindNull(sc, addr);
+    }
+  }
 }
diff --git a/junixsocket-common/src/test/java/org/newsclub/net/unix/domain/SocketChannelTest.java b/junixsocket-common/src/test/java/org/newsclub/net/unix/domain/SocketChannelTest.java
@@ -20,6 +20,7 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.net.ProtocolFamily;
+import java.net.SocketAddress;
 import java.nio.channels.DatagramChannel;
 import java.nio.channels.ServerSocketChannel;
 import java.nio.channels.SocketChannel;
@@ -75,4 +76,19 @@ public void testUnixDomainProtocolFamily() throws Exception {
       assertEquals(AFUNIXDatagramChannel.class, ch.getClass());
     }
   }
+
+  @Override
+  protected boolean mayTestBindNullThrowUnsupportedOperationException() {
+    return false;
+  }
+
+  @Override
+  protected boolean mayTestBindNullHaveNullLocalSocketAddress() {
+    return false;
+  }
+
+  @Override
+  protected void cleanupTestBindNull(ServerSocketChannel sc, SocketAddress addr) throws Exception {
+    // nothing to do, as -- unlike JEP380 -- junixsocket cleans up its mess
+  }
 }
diff --git a/junixsocket-common/src/test/java/org/newsclub/net/unix/jep380/SocketChannelTest.java b/junixsocket-common/src/test/java/org/newsclub/net/unix/jep380/SocketChannelTest.java
@@ -17,19 +17,50 @@
  */
 package org.newsclub.net.unix.jep380;
 
+import java.io.IOException;
 import java.net.SocketAddress;
+import java.nio.channels.ServerSocketChannel;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 
 import org.newsclub.net.unix.AFSocketCapability;
 import org.newsclub.net.unix.AFSocketCapabilityRequirement;
 
 import com.kohlschutter.annotations.compiletime.SuppressFBWarnings;
+import com.kohlschutter.testutil.AvailabilityRequirement;
 
 @AFSocketCapabilityRequirement(AFSocketCapability.CAPABILITY_UNIX_DOMAIN)
+@AvailabilityRequirement(classes = "java.net.UnixDomainSocketAddress", //
+    message = "This test requires Java 16 or later")
 @SuppressFBWarnings("NM_SAME_SIMPLE_NAME_AS_SUPERCLASS")
 public final class SocketChannelTest extends
     org.newsclub.net.unix.SocketChannelTest<SocketAddress> {
 
   public SocketChannelTest() {
     super(JEP380AddressSpecifics.INSTANCE);
   }
+
+  @Override
+  protected boolean mayTestBindNullThrowUnsupportedOperationException() {
+    return false;
+  }
+
+  @Override
+  protected boolean mayTestBindNullHaveNullLocalSocketAddress() {
+    return false;
+  }
+
+  @Override
+  protected void cleanupTestBindNull(ServerSocketChannel sc, SocketAddress addr)
+      throws ClassNotFoundException, IOException {
+    if (!Class.forName("java.net.UnixDomainSocketAddress").isAssignableFrom(addr.getClass())) {
+      return;
+    }
+
+    // JEP380 doesn't clean up socket files
+    Path p = Paths.get(addr.toString());
+    Files.delete(p);
+  }
+
 }
