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authorGregory Nutt <gnutt@nuttx.org>2014-09-28 11:28:17 -0600
committerGregory Nutt <gnutt@nuttx.org>2014-09-28 11:28:17 -0600
commit03c70a479f674f8564927fe1294f26fc09d9dfb7 (patch)
tree1b603aebec6148e4fca69eaa7fb752bf38b8e040 /nuttx/fs/dirent
parent91eed407dc2dfe1234f3748423d2699493c796b9 (diff)
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Move mount-related files from fs/. to fs/mount/.
Diffstat (limited to 'nuttx/fs/dirent')
-rw-r--r--nuttx/fs/dirent/Make.defs2
-rw-r--r--nuttx/fs/dirent/fs_seekdir.c235
2 files changed, 236 insertions, 1 deletions
diff --git a/nuttx/fs/dirent/Make.defs b/nuttx/fs/dirent/Make.defs
index 392fa444e..c50792cc6 100644
--- a/nuttx/fs/dirent/Make.defs
+++ b/nuttx/fs/dirent/Make.defs
@@ -37,7 +37,7 @@
ifneq ($(CONFIG_NFILE_DESCRIPTORS),0)
-CSRCS += fs_closedir.c fs_opendir.c fs_readdir.c fs_rewinddir.c
+CSRCS += fs_closedir.c fs_opendir.c fs_readdir.c fs_rewinddir.c fs_seekdir.c
# Include dirent build support
diff --git a/nuttx/fs/dirent/fs_seekdir.c b/nuttx/fs/dirent/fs_seekdir.c
new file mode 100644
index 000000000..c5d5fbcbb
--- /dev/null
+++ b/nuttx/fs/dirent/fs_seekdir.c
@@ -0,0 +1,235 @@
+/****************************************************************************
+ * fs/dirent/fs_seekdir.c
+ *
+ * Copyright (C) 2007, 2008, 2011, 2014 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.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;
+
+ /* Verify that we were provided with a valid directory structure,
+ * A special case is when we enumerate an "empty", unused inode (fd_root
+ * == 0). That is an inode in the pseudo-filesystem that has no
+ * operations and no children. This is a "dangling" directory entry that
+ * has lost its children.
+ */
+
+ 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);
+ }
+}