1 files changed, 122 insertions, 0 deletions
diff --git a/nuttx/fs/fs_filedup.c b/nuttx/fs/fs_filedup.c
new file mode 100644
index 000000000..b7eeb7add
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+++ b/nuttx/fs/fs_filedup.c
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+/****************************************************************************
+ * fs/fs_filedup.c
+ *
+ *   Copyright (C) 2007-2009, 2011-2012 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 <sched.h>
+#include <errno.h>
+
+#include <nuttx/fs/fs.h>
+
+#include "fs_internal.h"
+
+#if CONFIG_NFILE_DESCRIPTORS > 0
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define DUP_ISOPEN(fd, list) \
+  ((unsigned int)fd < CONFIG_NFILE_DESCRIPTORS && \
+   list->fl_files[fd].f_inode != NULL)
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: file_dup OR dup
+ *
+ * Description:
+ *   Clone a file descriptor 'fd' to an arbitray 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().
+ *
+ ****************************************************************************/
+
+int file_dup(int fildes, int minfd)
+{
+  FAR struct filelist *list;
+  int fildes2;
+
+  /* Get the thread-specific file list */
+
+  list = sched_getfiles();
+  if (!list)
+    {
+      set_errno(EMFILE);
+      return ERROR;
+    }
+
+  /* Verify that fildes is a valid, open file descriptor */
+
+  if (!DUP_ISOPEN(fildes, list))
+    {
+      set_errno(EBADF);
+      return ERROR;
+    }
+
+  /* Increment the reference count on the contained inode */
+
+  inode_addref(list->fl_files[fildes].f_inode);
+
+  /* Then allocate a new file descriptor for the inode */
+
+  fildes2 = files_allocate(list->fl_files[fildes].f_inode,
+                           list->fl_files[fildes].f_oflags,
+                           list->fl_files[fildes].f_pos,
+                           minfd);
+  if (fildes2 < 0)
+    {
+      set_errno(EMFILE);
+      inode_release(list->fl_files[fildes].f_inode);
+      return ERROR;
+    }
+
+  return fildes2;
+}
+
+#endif /* CONFIG_NFILE_DESCRIPTORS > 0 */
+