Resync new repository with old repo r5166

git-svn-id: http://svn.code.sf.net/p/nuttx/code/trunk@5153 42af7a65-404d-4744-a932-0658087f49c3
2026-11-06 05:11:36 +08:00 · 2012-09-17 18:18:44 +00:00
commit 57623d42eb
5691 changed files with 1361853 additions and 0 deletions
@@ -0,0 +1,230 @@
+/****************************************************************************
+ * fs/fs_seekdir.c
+ *
+ *   Copyright (C) 2007, 2008, 2011 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/types.h>
+#include <dirent.h>
+#include <errno.h>
+
+#include <nuttx/fs/fs.h>
+#include <nuttx/fs/dirent.h>
+
+#include "fs_internal.h"
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: seekpseudodir
+ ****************************************************************************/
+
+static inline void seekpseudodir(struct fs_dirent_s *idir, off_t offset)
+{
+  struct inode *curr;
+  struct inode *prev;
+  off_t pos;
+
+  /* Determine a starting point for the seek.  If the seek
+   * is "forward" from the current position, then we will
+   * start at the current poisition.  Otherwise, we will
+   * "rewind" to the root dir.
+   */
+
+  if ( offset < idir->fd_position )
+    {
+      pos  = 0;
+      curr = idir->fd_root;
+    }
+  else
+    {
+      pos  = idir->fd_position;
+      curr = idir->u.pseudo.fd_next;
+    }
+
+  /* Traverse the peer list starting at the 'root' of the
+   * the list until we find the node at 'offset".  If devices
+   * are being registered and unregistered, then this can
+   * be a very unpredictable operation.
+   */
+
+  inode_semtake();
+  for (; curr && pos != offset; pos++, curr = curr->i_peer);
+
+  /* Now get the inode to vist next time that readdir() is called */
+
+  prev                   = idir->u.pseudo.fd_next;
+  idir->u.pseudo.fd_next = curr; /* The next node to visit (might be null) */
+  idir->fd_position      = pos;  /* Might be beyond the last dirent */
+
+  if (curr)
+    {
+      /* Increment the reference count on this next node */
+
+      curr->i_crefs++;
+    }
+
+  inode_semgive();
+
+  if (prev)
+    {
+      inode_release(prev);
+    }
+}
+
+/****************************************************************************
+ * Name: seekmountptdir
+ ****************************************************************************/
+
+#ifndef CONFIG_DISABLE_MOUNTPOINT
+static inline void seekmountptdir(struct fs_dirent_s *idir, off_t offset)
+{
+  struct inode *inode;
+  off_t pos;
+
+  /* Determine a starting point for the seek.  If the seek
+   * is "forward" from the current position, then we will
+   * start at the current poisition.  Otherwise, we will
+   * "rewind" to the root dir.
+   */
+
+  inode = idir->fd_root;
+  if ( offset < idir->fd_position )
+    {
+      if (inode->u.i_mops && inode->u.i_mops->rewinddir)
+        {
+          /* Perform the rewinddir() operation */
+
+          inode->u.i_mops->rewinddir(inode, idir);
+          pos = 0;
+        }
+      else
+        {
+          /* We can't do the seek and there is no way to return
+           * an error indication.
+           */
+
+          return;
+        }
+    }
+  else
+    {
+      pos = idir->fd_position;
+    }
+
+  /* This is a brute force approach... we will just read
+   * directory entries until we are at the desired position.
+   */
+
+  while (pos < offset)
+    {
+      if (!inode->u.i_mops || !inode->u.i_mops->readdir ||
+           inode->u.i_mops->readdir(inode, idir) < 0)
+        {
+          /* We can't read the next entry and there is no way to return
+           * an error indication.
+           */
+
+           return;
+        }
+
+      /* Increment the position on each successful read */
+
+      pos++;
+    }
+
+  /* If we get here the directory position has been successfully set */
+
+  idir->fd_position = pos;
+}
+#endif
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: seekdir
+ *
+ * Description:
+ *   The seekdir() function sets the location in the directory stream from
+ *   which the next readdir() call will start.  seekdir() should be used with
+ *   an offset returned by telldir().
+ *
+ * Inputs:
+ *   dirp -- An instance of type DIR created by a previous
+ *     call to opendir();
+ *   offset -- offset to seek to
+ *
+ * Return:
+ *   None
+ *
+ ****************************************************************************/
+
+void seekdir(FAR DIR *dirp, off_t offset)
+{
+  struct fs_dirent_s *idir = (struct fs_dirent_s *)dirp;
+
+  /* Sanity checks */
+
+  if (!idir || !idir->fd_root)
+    {
+      return;
+    }
+
+  /* The way we handle the readdir depends on the type of inode
+   * that we are dealing with.
+   */
+
+#ifndef CONFIG_DISABLE_MOUNTPOINT
+  if (INODE_IS_MOUNTPT(idir->fd_root))
+    {
+      /* The node is a file system mointpoint */
+
+      seekmountptdir(idir, offset);
+    }
+  else
+#endif
+    {
+      /* The node is part of the root pseudo file system */
+
+      seekpseudodir(idir, offset);
+    }
+}