1 files changed, 149 insertions, 0 deletions
diff --git a/nuttx/net/socket/net_dupsd.c b/nuttx/net/socket/net_dupsd.c
new file mode 100644
index 000000000..3d286923e
--- /dev/null
+++ b/nuttx/net/socket/net_dupsd.c
@@ -0,0 +1,149 @@
+/****************************************************************************
+ * net/socket/net_dupsd.c
+ *
+ *   Copyright (C) 2009 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/socket.h>
+#include <sched.h>
+#include <errno.h>
+#include <debug.h>
+
+#include "socket/socket.h"
+
+#if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function: net_dupsd
+ *
+ * Description:
+ *   Clone a socket descriptor to an arbitray descriptor number.  If file
+ *   descriptors are implemented, then this is called by dup() for the case
+ *   of socket file descriptors.  If file descriptors are not implemented,
+ *   then this function IS dup().
+ *
+ ****************************************************************************/
+
+int net_dupsd(int sockfd, int minsd)
+{
+  FAR struct socket *psock1 = sockfd_socket(sockfd);
+  FAR struct socket *psock2;
+  int sockfd2;
+  int err;
+  int ret;
+
+  /* Make sure that the minimum socket descriptor is within the legal range.
+   * the minimum value we receive is relative to file descriptor 0;  we need
+   * map it relative of the first socket descriptor.
+   */
+
+#if CONFIG_NFILE_DESCRIPTORS > 0
+  if (minsd >= CONFIG_NFILE_DESCRIPTORS)
+    {
+      minsd -= CONFIG_NFILE_DESCRIPTORS;
+    }
+  else
+    {
+      minsd = 0;
+    }
+#endif
+
+  /* Lock the scheduler throughout the following */
+
+  sched_lock();
+
+  /* Get the socket structure underlying sockfd */
+
+  psock1 = sockfd_socket(sockfd);
+
+ /* Verify that the sockfd corresponds to valid, allocated socket */
+
+  if (!psock1 || psock1->s_crefs <= 0)
+    {
+      err = EBADF;
+      goto errout;
+    }
+
+  /* Allocate a new socket descriptor */
+
+  sockfd2 = sockfd_allocate(minsd);
+  if (sockfd2 < 0)
+    {
+      err = ENFILE;
+      goto errout;
+    }
+
+  /* Get the socket structure underlying the new descriptor */
+
+  psock2 = sockfd_socket(sockfd2);
+  if (!psock2)
+    {
+      err = ENOSYS; /* should not happen */
+      goto errout;
+    }
+
+  /* Duplicate the socket state */
+
+  ret = net_clone(psock1, psock2);
+  if (ret < 0)
+    {
+      err = -ret;
+      goto errout;
+
+    }
+
+  sched_unlock();
+  return sockfd2;
+
+errout:
+  sched_unlock();
+  errno = err;
+  return ERROR;
+}
+
+#endif /* defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0 */
+
+