1 files changed, 312 insertions, 0 deletions
diff --git a/nuttx/fs/fs_opendir.c b/nuttx/fs/fs_opendir.c
new file mode 100644
index 000000000..a52c538fe
--- /dev/null
+++ b/nuttx/fs/fs_opendir.c
@@ -0,0 +1,312 @@
+/****************************************************************************
+ * fs/fs_opendir.c
+ *
+ *   Copyright (C) 2007-2009, 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 <stdbool.h>
+#include <dirent.h>
+#include <string.h>
+#include <assert.h>
+#include <errno.h>
+
+#include <nuttx/kmalloc.h>
+#include <nuttx/fs/fs.h>
+#include <nuttx/fs/dirent.h>
+
+#include "fs_internal.h"
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: open_mountpoint
+ *
+ * Description:
+ *   Handle the case where the inode to be opened is within a mountpoint.
+ *
+ * Inputs:
+ *   inode -- the inode of the mountpoint to open
+ *   relpath -- the relative path within the mountpoint to open
+ *   dir -- the dirent structure to be initialized
+ *
+ * Return:
+ *   On success, OK is returned; Otherwise, a positive errno is returned.
+ *
+ ****************************************************************************/
+
+#ifndef CONFIG_DISABLE_MOUNTPOINT
+static inline int open_mountpoint(FAR struct inode *inode,
+                                  FAR const char *relpath,
+                                  FAR struct fs_dirent_s *dir)
+{
+  int ret;
+
+  /* The inode itself as the 'root' of mounted volume.  The actually
+   * directory is at relpath into the* mounted filesystem.
+   *
+   * Verify that the mountpoint inode  supports the opendir() method
+   */
+
+  if (!inode->u.i_mops || !inode->u.i_mops->opendir)
+    {
+       return ENOSYS;
+    }
+
+  /* Take reference to the mountpoint inode (fd_root).  Note that we do
+   * not use inode_addref() because we already hold the tree semaphore.
+   */
+
+  inode->i_crefs++;
+
+  /* Perform the opendir() operation */
+
+  ret = inode->u.i_mops->opendir(inode, relpath, dir);
+  if (ret < 0)
+    {
+      /* We now need to back off our reference to the inode.  We can't
+       * call inode_release() to do that unless we release the tree
+       * semaphore.  The following should be safe because:  (1) after the
+       * reference count was incremented above it should be >=1 so it should
+       * not decrement below zero, and (2) we hold the tree semaphore so no
+       * other thread should be able to change the reference count.
+       */
+
+      inode->i_crefs--;
+      DEBUGASSERT(inode->i_crefs >= 0);
+
+      /* Negate the error value so that it can be used to set errno */
+
+      return -ret;
+    }
+
+  return OK;
+}
+#endif
+
+/****************************************************************************
+ * Name: open_pseudodir
+ *
+ * Description:
+ *   Handle the case where the inode to be opened is within the top-level
+ *   pseudo-file system.
+ *
+ * Inputs:
+ *   inode -- the inode of the mountpoint to open
+ *   dir -- the dirent structure to be initialized
+ *
+ * Return:
+ *   On success, OK is returned; Otherwise, a positive errno is returned.
+ *
+ ****************************************************************************/
+
+static void open_pseudodir(FAR struct inode *inode, FAR struct fs_dirent_s *dir)
+{
+  /* We have a valid psuedo-filesystem node.  Take two references on the
+   * inode -- one for the parent (fd_root) and one for the child (fd_next).
+   * Note that we do not call inode_addref because we are holding the tree
+   * semaphore and that would result in deadlock.
+   */
+
+  inode->i_crefs += 2;
+  dir->u.psuedo.fd_next = inode; /* This is the next node to use for readdir() */
+
+  /* Flag the inode as belonging to the psuedo-filesystem */
+
+#ifndef CONFIG_DISABLE_MOUNTPOINT
+  DIRENT_SETPSUEDONODE(dir->fd_flags);
+#endif
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: opendir
+ *
+ * Description:
+ *   The  opendir() function opens a directory stream corresponding to the
+ *   directory name, and returns a pointer to the directory stream. The
+ *   stream is positioned at the first entry in the directory.
+ *
+ * Inputs:
+ *   path -- the directory to open
+ *
+ * Return:
+ *   The opendir() function returns a pointer to the directory stream.  On
+ *   error, NULL is returned, and errno is set appropriately.
+ *
+ *   EACCES  - Permission denied.
+ *   EMFILE  - Too many file descriptors in use by process.
+ *   ENFILE  - Too many files are currently open in the
+ *             system.
+ *   ENOENT  - Directory does not exist, or name is an empty
+ *             string.
+ *   ENOMEM  - Insufficient memory to complete the operation.
+ *   ENOTDIR - 'path' is not a directory.
+ *
+ ****************************************************************************/
+
+FAR DIR *opendir(FAR const char *path)
+{
+  FAR struct inode *inode = NULL;
+  FAR struct fs_dirent_s *dir;
+  FAR const char *relpath;
+  bool bisroot = false;
+  int ret;
+
+  /* If we are given 'nothing' then we will interpret this as
+   * request for the root inode.
+   */
+
+  inode_semtake();
+  if (!path || *path == 0 || strcmp(path, "/") == 0)
+    {
+      inode   = root_inode;
+      bisroot = true;
+      relpath = NULL;
+    }
+  else
+    {
+      /* We don't know what to do with relative pathes */
+
+      if (*path != '/')
+        {
+          ret = -ENOTDIR;
+          goto errout_with_semaphore;
+        }
+
+      /* Find the node matching the path. */
+
+      inode = inode_search(&path, (FAR struct inode**)NULL, (FAR struct inode**)NULL, &relpath);
+    }
+
+  /* Did we get an inode? */
+
+  if (!inode)
+    {
+      /* 'path' is not a does not exist.*/
+
+      ret = ENOTDIR;
+      goto errout_with_semaphore;
+    }
+
+  /* Allocate a type DIR -- which is little more than an inode
+   * container.
+   */
+
+  dir = (FAR struct fs_dirent_s *)kzalloc(sizeof(struct fs_dirent_s));
+  if (!dir)
+    {
+      /* Insufficient memory to complete the operation.*/
+
+      ret = ENOMEM;
+      goto errout_with_semaphore;
+    }
+
+  /* Populate the DIR structure and return it to the caller.  The way that
+   * we do this depends on whenever this is a "normal" psuedo-file-system
+   * inode or a file system mountpoint.
+   */
+
+  dir->fd_root     = inode;  /* Save the inode where we start */
+  dir->fd_position = 0;      /* This is the position in the read stream */
+
+  /* First, handle the special case of the root inode.  This must be
+   * special-cased here because the root inode might ALSO be a mountpoint.
+   */
+
+  if (bisroot)
+    {
+      /* Whatever payload the root inode carries, the root inode is always
+       * a directory inode in the pseudo-file system
+       */
+
+      open_pseudodir(inode, dir);
+    }
+
+  /* Is this a node in the psuedo filesystem? Or a mountpoint?  If the node
+   * is the root (bisroot == TRUE), then this is a special case.
+   */
+
+#ifndef CONFIG_DISABLE_MOUNTPOINT
+   else if (INODE_IS_MOUNTPT(inode))
+     {
+       /* Yes, the node is a file system mointpoint. */
+
+      ret = open_mountpoint(inode, relpath, dir);
+      if (ret != OK)
+        {
+           goto errout_with_direntry;
+        }
+    }
+#endif
+  else
+    {
+      /* The node is part of the root psuedo file system.  Does the inode have a child?
+       * If so that the child would be the 'root' of a list of nodes under
+       * the directory.
+       */
+
+      inode = inode->i_child;
+      if (!inode)
+        {
+          ret = ENOTDIR;
+          goto errout_with_direntry;
+        }
+
+      /* It looks we have a valid psuedo-filesystem directory node. */
+
+      open_pseudodir(inode, dir);
+    }
+
+  inode_semgive();
+  return ((DIR*)dir);
+
+  /* Nasty goto's make error handling simpler */
+
+errout_with_direntry:
+  kfree(dir);
+
+errout_with_semaphore:
+  inode_semgive();
+  set_errno(ret);
+  return NULL;
+}