diff --git a/fs/vfs/fs_dup.c b/fs/vfs/fs_dup.c
index a85e8c94407..5848877ea20 100644
--- a/fs/vfs/fs_dup.c
+++ b/fs/vfs/fs_dup.c
@@ -50,6 +50,59 @@
  * Public Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: nx_dup
+ *
+ * Description:
+ *   nx_dup() is similar to the standard 'dup' interface except that is
+ *   not a cancellation point and it does not modify the errno variable.
+ *
+ *   nx_dup() is an internal NuttX interface and should not be called from
+ *   applications.
+ *
+ * Returned Value:
+ *   The new file descriptor is returned on success; a negated errno value is
+ *   returned on any failure.
+ *
+ ****************************************************************************/
+
+int nx_dup(int fd)
+{
+  /* Check the range of the descriptor to see if we got a file or a socket
+   * descriptor.
+   */
+
+  if (fd < CONFIG_NFILE_DESCRIPTORS)
+    {
+      /* Its a valid file descriptor.. dup the file descriptor using any
+       * other file descriptor.
+       */
+
+      return fs_dupfd(fd, 0);
+    }
+  else
+    {
+      /* Not a valid file descriptor.
+       * Did we get a valid socket descriptor?
+       */
+
+#ifdef CONFIG_NET
+      if (fd < (CONFIG_NFILE_DESCRIPTORS + CONFIG_NSOCKET_DESCRIPTORS))
+        {
+          /* Yes.. dup the socket descriptor. */
+
+          return net_dup(fd, CONFIG_NFILE_DESCRIPTORS);
+        }
+      else
+#endif
+        {
+          /* No.. then it is a bad descriptor number */
+
+          return -EBADF;
+        }
+    }
+}
+
 /****************************************************************************
  * Name: dup
  *
@@ -60,47 +113,13 @@
 
 int dup(int fd)
 {
-  int ret = OK;
+  int ret;
 
-  /* Check the range of the descriptor to see if we got a file or a socket
-   * descriptor.
-   */
-
-  if ((unsigned int)fd < CONFIG_NFILE_DESCRIPTORS)
+  ret = nx_dup(fd);
+  if (ret < 0)
     {
-      /* Its a valid file descriptor.. dup the file descriptor using any
-       * other file descriptor.  fd_dupfd() sets the errno value in the
-       * event of any failures.
-       */
-
-      ret = fs_dupfd(fd, 0);
-    }
-  else
-    {
-      /* Not a valid file descriptor.  Did we get a valid socket descriptor? */
-
-#ifdef CONFIG_NET
-      if ((unsigned int)fd < (CONFIG_NFILE_DESCRIPTORS + CONFIG_NSOCKET_DESCRIPTORS))
-        {
-          /* Yes.. dup the socket descriptor.  The errno value is not set. */
-
-          ret = net_dup(fd, CONFIG_NFILE_DESCRIPTORS);
-        }
-      else
-#endif
-        {
-          /* No.. then it is a bad descriptor number */
-
-          ret = -EBADF;
-        }
-
-      /* Set the errno value on failures */
-
-      if (ret < 0)
-        {
-          set_errno(-ret);
-          ret = ERROR;
-        }
+      set_errno(-ret);
+      ret = ERROR;
     }
 
   return ret;
diff --git a/fs/vfs/fs_dup2.c b/fs/vfs/fs_dup2.c
index fdf4511da46..33ccf8fc391 100644
--- a/fs/vfs/fs_dup2.c
+++ b/fs/vfs/fs_dup2.c
@@ -46,17 +46,62 @@
 
 #include "inode/inode.h"
 
-/* This logic in this applies only when both socket and file descriptors are
- * in that case, this function discriminates which type of dup2 is being
- * performed.
- */
-
-#ifdef CONFIG_NET
-
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: nx_dup2
+ *
+ * Description:
+ *   nx_dup2() is similar to the standard 'dup2' interface except that is
+ *   not a cancellation point and it does not modify the errno variable.
+ *
+ *   nx_dup2() is an internal NuttX interface and should not be called from
+ *   applications.
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success; a negated errno value is return on
+ *   any failure.
+ *
+ ****************************************************************************/
+
+int nx_dup2(int fd1, int fd2)
+{
+  /* Check the range of the descriptor to see if we got a file or a socket
+   * descriptor.
+   */
+
+  if (fd1 >= CONFIG_NFILE_DESCRIPTORS)
+    {
+      /* Not a valid file descriptor.
+       * Did we get a valid socket descriptor?
+       */
+
+#ifdef CONFIG_NET
+      if (fd1 < (CONFIG_NFILE_DESCRIPTORS + CONFIG_NSOCKET_DESCRIPTORS))
+        {
+          /* Yes.. dup the socket descriptor. */
+
+          return net_dup2(fd1, fd2);
+        }
+      else
+#endif
+        {
+          /* No.. then it is a bad descriptor number */
+
+          return -EBADF;
+        }
+    }
+  else
+    {
+      /* Its a valid file descriptor.. dup the file descriptor.
+       */
+
+      return fs_dupfd2(fd1, fd2);
+    }
+}
+
 /****************************************************************************
  * Name: dup2
  *
@@ -68,47 +113,14 @@
 
 int dup2(int fd1, int fd2)
 {
-  /* Check the range of the descriptor to see if we got a file or a socket
-   * descriptor.
-   */
+  int ret;
 
-  if ((unsigned int)fd1 >= CONFIG_NFILE_DESCRIPTORS)
+  ret = nx_dup2(fd1, fd2);
+  if (ret < 0)
     {
-      int ret;
-
-      /* Not a valid file descriptor.  Did we get a valid socket descriptor? */
-
-      if ((unsigned int)fd1 < (CONFIG_NFILE_DESCRIPTORS + CONFIG_NSOCKET_DESCRIPTORS))
-        {
-          /* Yes.. dup the socket descriptor. The errno value is not set. */
-
-          ret = net_dup2(fd1, fd2);
-        }
-      else
-        {
-          /* No.. then it is a bad descriptor number */
-
-          ret = -EBADF;
-        }
-
-      /* Set the errno value on failures */
-
-      if (ret < 0)
-        {
-          set_errno(-ret);
-          ret = ERROR;
-        }
-
-      return ret;
+      set_errno(-ret);
+      ret = ERROR;
     }
-  else
-    {
-      /* Its a valid file descriptor.. dup the file descriptor.  fd_dupfd()
-       * sets the errno value in the event of any failures.
-       */
 
-      return fs_dupfd2(fd1, fd2);
-    }
+  return ret;
 }
-
-#endif /* CONFIG_NET */
diff --git a/fs/vfs/fs_dupfd.c b/fs/vfs/fs_dupfd.c
index dd323d5166a..d8bd080c893 100644
--- a/fs/vfs/fs_dupfd.c
+++ b/fs/vfs/fs_dupfd.c
@@ -47,8 +47,7 @@
  *
  * Description:
  *   Equivalent to the non-standard fs_dupfd() function except that it
- *   accepts a struct file instance instead of a file descriptor and does
- *   not set the errno variable.
+ *   accepts a struct file instance instead of a file descriptor.
  *
  * Returned Value:
  *   Zero (OK) is returned on success; a negated errno value is returned on
@@ -89,19 +88,15 @@ int file_dup(FAR struct file *filep, int minfd)
 }
 
 /****************************************************************************
- * Name: fs_dupfd OR dup
+ * Name: fs_dupfd
  *
  * Description:
  *   Clone a file descriptor 'fd' to an arbitrary descriptor number (any
- *   value greater than or equal to 'minfd'). If socket descriptors are
- *   implemented, then this is called by dup() for the case of file
- *   descriptors.  If socket descriptors are not implemented, then this
- *   function IS dup().
+ *   value greater than or equal to 'minfd').
  *
  * Returned Value:
- *   fs_dupfd is sometimes an OS internal function and sometimes is a direct
- *   substitute for dup().  So it must return an errno value as though it
- *   were dup().
+ *   Zero (OK) is returned on success; a negated errno value is returned on
+ *   any failure.
  *
  ****************************************************************************/
 
@@ -115,22 +110,12 @@ int fs_dupfd(int fd, int minfd)
   ret = fs_getfilep(fd, &filep);
   if (ret < 0)
     {
-      goto errout;
+      return ret;
     }
 
   DEBUGASSERT(filep != NULL);
 
   /* Let file_dup() do the real work */
 
-  ret = file_dup(filep, minfd);
-  if (ret < 0)
-    {
-      goto errout;
-    }
-
-  return ret;
-
-errout:
-  set_errno(-ret);
-  return ERROR;
+  return file_dup(filep, minfd);
 }
diff --git a/fs/vfs/fs_dupfd2.c b/fs/vfs/fs_dupfd2.c
index 0d0f35cf8ad..d314a224acc 100644
--- a/fs/vfs/fs_dupfd2.c
+++ b/fs/vfs/fs_dupfd2.c
@@ -61,26 +61,18 @@
  ****************************************************************************/
 
 /****************************************************************************
- * Name: fs_dupfd2 OR dup2
+ * Name: fs_dupfd2
  *
  * Description:
- *   Clone a file descriptor to a specific descriptor number. If socket
- *   descriptors are implemented, then this is called by dup2() for the
- *   case of file descriptors.  If socket descriptors are not implemented,
- *   then this function IS dup2().
+ *   Clone a file descriptor to a specific descriptor number.
  *
  * Returned Value:
- *   fs_dupfd is sometimes an OS internal function and sometimes is a direct
- *   substitute for dup2().  So it must return an errno value as though it
- *   were dup2().
+ *   Zero (OK) is returned on success; a negated errno value is return on
+ *   any failure.
  *
  ****************************************************************************/
 
-#ifdef CONFIG_NET
 int fs_dupfd2(int fd1, int fd2)
-#else
-int dup2(int fd1, int fd2)
-#endif
 {
   FAR struct file *filep1;
   FAR struct file *filep2 = NULL;
@@ -96,7 +88,7 @@ int dup2(int fd1, int fd2)
 
   if (ret < 0)
     {
-      goto errout;
+      return ret;
     }
 
   DEBUGASSERT(filep1 != NULL && filep2 != NULL);
@@ -105,8 +97,7 @@ int dup2(int fd1, int fd2)
 
   if (!DUP_ISOPEN(filep1))
     {
-      ret = -EBADF;
-      goto errout;
+      return -EBADF;
     }
 
   /* Handle a special case */
@@ -118,15 +109,5 @@ int dup2(int fd1, int fd2)
 
   /* Perform the dup2 operation */
 
-  ret = file_dup2(filep1, filep2);
-  if (ret < 0)
-    {
-      goto errout;
-    }
-
-  return OK;
-
-errout:
-  set_errno(-ret);
-  return ERROR;
+  return file_dup2(filep1, filep2);
 }
diff --git a/include/nuttx/fs/fs.h b/include/nuttx/fs/fs.h
index 8343c361a41..9f866f2cde0 100644
--- a/include/nuttx/fs/fs.h
+++ b/include/nuttx/fs/fs.h
@@ -721,8 +721,7 @@ void files_releaselist(FAR struct filelist *list);
  *
  * Description:
  *   Equivalent to the non-standard fs_dupfd() function except that it
- *   accepts a struct file instance instead of a file descriptor and does
- *   not set the errno variable.
+ *   accepts a struct file instance instead of a file descriptor.
  *
  * Returned Value:
  *   Zero (OK) is returned on success; a negated errno value is returned on
@@ -733,27 +732,41 @@ void files_releaselist(FAR struct filelist *list);
 int file_dup(FAR struct file *filep, int minfd);
 
 /****************************************************************************
- * Name: fs_dupfd OR dup
+ * Name: fs_dupfd
  *
  * Description:
  *   Clone a file descriptor 'fd' to an arbitrary descriptor number (any
- *   value greater than or equal to 'minfd'). If socket descriptors are
- *   implemented, then this is called by dup() for the case of file
- *   descriptors.  If socket descriptors are not implemented, then this
- *   function IS dup().
+ *   value greater than or equal to 'minfd').
  *
  *   This alternative naming is used when dup could operate on both file and
  *   socket descriptors to avoid drawing unused socket support into the link.
  *
  * Returned Value:
- *   fs_dupfd is sometimes an OS internal function and sometimes is a direct
- *   substitute for dup().  So it must return an errno value as though it
- *   were dup().
+ *   Zero (OK) is returned on success; a negated errno value is returned on
+ *   any failure.
  *
  ****************************************************************************/
 
 int fs_dupfd(int fd, int minfd);
 
+/****************************************************************************
+ * Name: nx_dup
+ *
+ * Description:
+ *   nx_dup() is similar to the standard 'dup' interface except that is
+ *   not a cancellation point and it does not modify the errno variable.
+ *
+ *   nx_dup() is an internal NuttX interface and should not be called from
+ *   applications.
+ *
+ * Returned Value:
+ *   The new file descriptor is returned on success; a negated errno value is
+ *   returned on any failure.
+ *
+ ****************************************************************************/
+
+int nx_dup(int fd);
+
 /****************************************************************************
  * Name: file_dup2
  *
@@ -762,8 +775,7 @@ int fs_dupfd(int fd, int minfd);
  *   dup2.
  *
  *   Equivalent to the non-standard fs_dupfd2() function except that it
- *   accepts struct file instances instead of file descriptors and it does
- *   not set the errno variable.
+ *   accepts struct file instances instead of file descriptors.
  *
  * Returned Value:
  *   Zero (OK) is returned on success; a negated errno value is return on
@@ -774,29 +786,39 @@ int fs_dupfd(int fd, int minfd);
 int file_dup2(FAR struct file *filep1, FAR struct file *filep2);
 
 /****************************************************************************
- * Name: fs_dupfd2 OR dup2
+ * Name: fs_dupfd2
  *
  * Description:
- *   Clone a file descriptor to a specific descriptor number. If socket
- *   descriptors are implemented, then this is called by dup2() for the
- *   case of file descriptors.  If socket descriptors are not implemented,
- *   then this function IS dup2().
+ *   Clone a file descriptor to a specific descriptor number.
  *
  *   This alternative naming is used when dup2 could operate on both file and
  *   socket descriptors to avoid drawing unused socket support into the link.
  *
  * Returned Value:
- *   fs_dupfd2 is sometimes an OS internal function and sometimes is a direct
- *   substitute for dup2().  So it must return an errno value as though it
- *   were dup2().
+ *   Zero (OK) is returned on success; a negated errno value is return on
+ *   any failure.
  *
  ****************************************************************************/
 
-#ifdef CONFIG_NET
 int fs_dupfd2(int fd1, int fd2);
-#else
-#  define fs_dupfd2(fd1, fd2) dup2(fd1, fd2)
-#endif
+
+/****************************************************************************
+ * Name: nx_dup2
+ *
+ * Description:
+ *   nx_dup2() is similar to the standard 'dup2' interface except that is
+ *   not a cancellation point and it does not modify the errno variable.
+ *
+ *   nx_dup2() is an internal NuttX interface and should not be called from
+ *   applications.
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success; a negated errno value is return on
+ *   any failure.
+ *
+ ****************************************************************************/
+
+int nx_dup2(int fd1, int fd2);
 
 /****************************************************************************
  * Name: file_open
diff --git a/include/nuttx/net/net.h b/include/nuttx/net/net.h
index bf240606059..871236f8176 100644
--- a/include/nuttx/net/net.h
+++ b/include/nuttx/net/net.h
@@ -1341,14 +1341,11 @@ int net_poll(int sockfd, struct pollfd *fds, bool setup);
  * Name: psock_dup
  *
  * Description:
- *   Clone a socket descriptor to an arbitrary 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().
+ *   Clone a socket descriptor to an arbitrary descriptor number.
  *
  * Returned Value:
- *   On success, returns the number of characters sent.  On any error,
- *   a negated errno value is returned:.
+ *   On success, returns the number of new socket.  On any error,
+ *   a negated errno value is returned.
  *
  ****************************************************************************/
 
@@ -1358,14 +1355,11 @@ int psock_dup(FAR struct socket *psock, int minsd);
  * Name: net_dup
  *
  * Description:
- *   Clone a socket descriptor to an arbitrary 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().
+ *   Clone a socket descriptor to an arbitrary descriptor number.
  *
  * Returned Value:
- *   On success, returns the number of characters sent.  On any error,
- *   a negated errno value is returned:.
+ *   On success, returns the number of new socket.  On any error,
+ *   a negated errno value is returned.
  *
  ****************************************************************************/
 
@@ -1385,14 +1379,11 @@ int psock_dup2(FAR struct socket *psock1, FAR struct socket *psock2);
  * Name: net_dup2
  *
  * Description:
- *   Clone a socket descriptor to an arbitrary descriptor number.  If file
- *   descriptors are implemented, then this is called by dup2() for the case
- *   of socket file descriptors.  If file descriptors are not implemented,
- *   then this function IS dup2().
+ *   Clone a socket descriptor to an arbitrary descriptor number.
  *
  * Returned Value:
- *   On success, returns the number of characters sent.  On any error,
- *   a negated errno value is returned:.
+ *   Zero (OK) is returned on success; a negated errno value is returned on
+ *   any failure.
  *
  ****************************************************************************/
 
diff --git a/net/socket/net_dup.c b/net/socket/net_dup.c
index 09fcbcaae06..e8a38804de1 100644
--- a/net/socket/net_dup.c
+++ b/net/socket/net_dup.c
@@ -54,14 +54,11 @@
  * Name: psock_dup
  *
  * Description:
- *   Clone a socket descriptor to an arbitrary 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().
+ *   Clone a socket descriptor to an arbitrary descriptor number.
  *
  * Returned Value:
- *   On success, returns the number of characters sent.  On any error,
- *   a negated errno value is returned:.
+ *   On success, returns the number of new socket.  On any error,
+ *   a negated errno value is returned.
  *
  ****************************************************************************/
 
@@ -138,14 +135,11 @@ errout:
  * Name: net_dup
  *
  * Description:
- *   Clone a socket descriptor to an arbitrary 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().
+ *   Clone a socket descriptor to an arbitrary descriptor number.
  *
  * Returned Value:
- *   On success, returns the number of characters sent.  On any error,
- *   a negated errno value is returned:.
+ *   On success, returns the number of new socket.  On any error,
+ *   a negated errno value is returned.
  *
  ****************************************************************************/
 
diff --git a/net/socket/net_dup2.c b/net/socket/net_dup2.c
index 2754772c9b9..1e9f4d25d83 100644
--- a/net/socket/net_dup2.c
+++ b/net/socket/net_dup2.c
@@ -106,7 +106,8 @@ int psock_dup2(FAR struct socket *psock1, FAR struct socket *psock2)
    * for this address family type.
    */
 
-  DEBUGASSERT(psock2->s_sockif != NULL && psock2->s_sockif->si_addref != NULL);
+  DEBUGASSERT(psock2->s_sockif != NULL &&
+              psock2->s_sockif->si_addref != NULL);
   psock2->s_sockif->si_addref(psock2);
 
 #ifdef NET_TCP_HAVE_STACK
@@ -156,14 +157,11 @@ int psock_dup2(FAR struct socket *psock1, FAR struct socket *psock2)
  * Name: net_dup2
  *
  * Description:
- *   Clone a socket descriptor to an arbitrary descriptor number.  If file
- *   descriptors are implemented, then this is called by dup2() for the case
- *   of socket file descriptors.  If file descriptors are not implemented,
- *   then this function IS dup2().
+ *   Clone a socket descriptor to an arbitrary descriptor number.
  *
  * Returned Value:
- *   On success, returns the number of characters sent.  On any error,
- *   a negated errno value is returned:.
+ *   Zero (OK) is returned on success; a negated errno value is returned on
+ *   any failure.
  *
  ****************************************************************************/