fix several blocking SocketChannel bugs

In java-nio.cpp, we can't use GetPrimitiveArrayCritical when reading
from or writing to blocking sockets since it may block the rest of the
VM indefinitely.

In SelectableChannel.java, we can't use a null test on
SelectableChannel.key to determine whether the channel is open since
it might never be registered with a Selector.  According to the Sun
documentation, a SelectableChannel is open as soon as it's created, so
that's what we now implement.

classpath/java-nio.cpp

@@ -428,13 +428,32 @@ Java_java_nio_channels_SocketChannel_natRead(JNIEnv *e,
 					     jint socket,
 					     jbyteArray buffer,
 					     jint offset,
-					     jint length)
+					     jint length,
+                                             jboolean blocking)
 {
+  int r;
+  if (blocking) {
+    uint8_t* buf = static_cast<uint8_t*>(allocate(e, length));
+    if (buf) {
+      r = ::doRead(socket, buf, length);
+      if (r > 0) {
+        e->SetByteArrayRegion
+          (buffer, offset, r, reinterpret_cast<jbyte*>(buf));
+      }
+      free(buf);
+    } else {
+      return 0;
+    }
+  } else {
     jboolean isCopy;
-  uint8_t *buf = static_cast<uint8_t*>
+    uint8_t* buf = static_cast<uint8_t*>
       (e->GetPrimitiveArrayCritical(buffer, &isCopy));
-  int r = ::doRead(socket, buf + offset, length);
+
+    r = ::doRead(socket, buf + offset, length);
+
     e->ReleasePrimitiveArrayCritical(buffer, buf, 0);
+  }
+
   if (r < 0) {
     if (eagain()) {
       return 0;
@@ -453,13 +472,30 @@ Java_java_nio_channels_SocketChannel_natWrite(JNIEnv *e,
 					      jint socket,
 					      jbyteArray buffer,
 					      jint offset,
-					      jint length)
+					      jint length,
+                                              jboolean blocking)
 {
+  int r;
+  if (blocking) {
+    uint8_t* buf = static_cast<uint8_t*>(allocate(e, length));
+    if (buf) {
+      e->GetByteArrayRegion
+        (buffer, offset, length, reinterpret_cast<jbyte*>(buf));
+      r = ::doWrite(socket, buf, length);
+      free(buf);
+    } else {
+      return 0;
+    }
+  } else {
     jboolean isCopy;
-  uint8_t *buf = static_cast<uint8_t*>
+    uint8_t* buf = static_cast<uint8_t*>
       (e->GetPrimitiveArrayCritical(buffer, &isCopy));
-  int r = ::doWrite(socket, buf + offset, length);
+
+    r = ::doWrite(socket, buf + offset, length);
+
     e->ReleasePrimitiveArrayCritical(buffer, buf, 0);
+  }
+
   if (r < 0) {
     if (eagain()) {
       return 0;

classpath/java/nio/channels/SelectableChannel.java

@@ -15,6 +15,7 @@ import java.nio.ByteBuffer;
 
 public abstract class SelectableChannel implements Channel {
   private SelectionKey key;
+  private boolean open = true;
 
   abstract int socketFD();
 
@@ -30,12 +31,11 @@ public abstract class SelectableChannel implements Channel {
   }
 
   public boolean isOpen() {
-    return key != null;
+    return open;
   }
 
   public void close() throws IOException {
-    if (key != null) {
+    open = false;
     key = null;
   }
-  }
 }

classpath/java/nio/channels/SocketChannel.java

@@ -92,7 +92,7 @@ public class SocketChannel extends SelectableChannel
     byte[] array = b.array();
     if (array == null) throw new NullPointerException();
 
-    int r = natRead(socket, array, b.arrayOffset() + b.position(), b.remaining());
+    int r = natRead(socket, array, b.arrayOffset() + b.position(), b.remaining(), blocking);
     if (r > 0) {
       b.position(b.position() + r);
     }
@@ -108,7 +108,7 @@ public class SocketChannel extends SelectableChannel
     byte[] array = b.array();
     if (array == null) throw new NullPointerException();
 
-    int w = natWrite(socket, array, b.arrayOffset() + b.position(), b.remaining());
+    int w = natWrite(socket, array, b.arrayOffset() + b.position(), b.remaining(), blocking);
     if (w > 0) {
       b.position(b.position() + w);
     }
@@ -139,9 +139,9 @@ public class SocketChannel extends SelectableChannel
     throws IOException;
   private static native boolean natFinishConnect(int socket)
     throws IOException;
-  private static native int natRead(int socket, byte[] buffer, int offset, int length)
+  private static native int natRead(int socket, byte[] buffer, int offset, int length, boolean blocking)
     throws IOException;
-  private static native int natWrite(int socket, byte[] buffer, int offset, int length)
+  private static native int natWrite(int socket, byte[] buffer, int offset, int length, boolean blocking)
     throws IOException;
   private static native void natThrowWriteError(int socket) throws IOException;
   private static native void natCloseSocket(int socket);