nuttx/fs/inode/inode.h

/****************************************************************************
 * fs/inode/inode.h
 *
 *   Copyright (C) 2007, 2009, 2012, 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.
 *
 ****************************************************************************/

#ifndef __FS_INODE_H
#define __FS_INODE_H

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <sys/types.h>
#include <stdint.h>
#include <dirent.h>

#include <nuttx/fs/fs.h>
#include <nuttx/compiler.h>

/****************************************************************************
 * Public Types
 ****************************************************************************/

/* Callback used by foreach_inode to traverse all inodes in the pseudo-
 * file system.
 */

typedef int (*foreach_inode_t)(FAR struct inode *node,
                               FAR char dirpath[PATH_MAX],
                               FAR void *arg);

/****************************************************************************
 * Public Data
 ****************************************************************************/

#undef EXTERN
#if defined(__cplusplus)
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif

EXTERN FAR struct inode *g_root_inode;

/****************************************************************************
 * Public Function Prototypes
 ****************************************************************************/

/****************************************************************************
 * Name: inode_initialize
 *
 * Description:
 *   This is called from the OS initialization logic to configure the file
 *   system.
 *
 ****************************************************************************/

void inode_initialize(void);

/****************************************************************************
 * Name: inode_semtake
 *
 * Description:
 *   Get exclusive access to the in-memory inode tree (tree_sem).
 *
 ****************************************************************************/

void inode_semtake(void);

/****************************************************************************
 * Name: inode_semgive
 *
 * Description:
 *   Relinquish exclusive access to the in-memory inode tree (tree_sem).
 *
 ****************************************************************************/

void inode_semgive(void);

/****************************************************************************
 * Name: inode_search
 *
 * Description:
 *   Find the inode associated with 'path' returning the inode references
 *   and references to its companion nodes.
 *
 * Assumptions:
 *   The caller holds the tree_sem
 *
 ****************************************************************************/

FAR struct inode *inode_search(FAR const char **path,
                               FAR struct inode **peer,
                               FAR struct inode **parent,
                               FAR const char **relpath);

/****************************************************************************
 * Name: inode_free
 *
 * Description:
 *   Free resources used by an inode
 *
 ****************************************************************************/

void inode_free(FAR struct inode *node);

/****************************************************************************
 * Name: inode_nextname
 *
 * Description:
 *   Given a path with node names separated by '/', return the next node
 *   name.
 *
 ****************************************************************************/

const char *inode_nextname(FAR const char *name);

/****************************************************************************
 * Name: inode_reserve
 *
 * Description:
 *   Reserve an (initialized) inode the pseudo file system.
 *
 *   NOTE: Caller must hold the inode semaphore
 *
 * Input parameters:
 *   path - The path to the inode to create
 *   inode - The location to return the inode pointer
 *
 * Returned Value:
 *   Zero on success (with the inode point in 'inode'); A negated errno
 *   value is returned on failure:
 *
 *   EINVAL - 'path' is invalid for this operation
 *   EEXIST - An inode already exists at 'path'
 *   ENOMEM - Failed to allocate in-memory resources for the operation
 *
 ****************************************************************************/

int inode_reserve(FAR const char *path, FAR struct inode **inode);

/****************************************************************************
 * Name: inode_unlink
 *
 * Description:
 *   Given a path, remove a the node from the in-memory, inode tree that the
 *   path refers to.  This is normally done in preparation to removing or
 *   moving an inode.
 *
 * Assumptions/Limitations:
 *   The caller must hold the inode semaphore
 *
 ****************************************************************************/

FAR struct inode *inode_unlink(FAR const char *path);

/****************************************************************************
 * Name: inode_remove
 *
 * Description:
 *   Given a path, remove a the node from the in-memory, inode tree that the
 *   path refers to and free all resources related to the inode.  If the
 *   inode is in-use, then it will be unlinked, but will not be freed until
 *   the last reference to the inode is released.
 *
 * Assumptions/Limitations:
 *   The caller must hold the inode semaphore
 *
 ****************************************************************************/

int inode_remove(FAR const char *path);

/****************************************************************************
 * Name: inode_find
 *
 * Description:
 *   This is called from the open() logic to get a reference to the inode
 *   associated with a path.
 *
 ****************************************************************************/

FAR struct inode *inode_find(FAR const char *path, const char **relpath);

/****************************************************************************
 * Name: inode_addref
 *
 * Description:
 *   Increment the reference count on an inode (as when a file descriptor
 *   is dup'ed).
 *
 ****************************************************************************/

void inode_addref(FAR struct inode *inode);

/****************************************************************************
 * Name: inode_release
 *
 * Description:
 *   This is called from close() logic when it no longer refers to the inode.
 *
 ****************************************************************************/

void inode_release(FAR struct inode *inode);

/****************************************************************************
 * Name: foreach_inode
 *
 * Description:
 *   Visit each inode in the pseudo-file system.  The traversal is terminated
 *   when the callback 'handler' returns a non-zero value, or when all of
 *   the inodes have been visited.
 *
 *   NOTE 1: Use with caution... The pseudo-file system is locked throughout
 *   the traversal.
 *   NOTE 2: The search algorithm is recursive and could, in principle, use
 *   an indeterminant amount of stack space.  This will not usually be a
 *   real work issue.
 *
 ****************************************************************************/

int foreach_inode(foreach_inode_t handler, FAR void *arg);

/****************************************************************************
 * Name: files_initialize
 *
 * Description:
 *   This is called from the FS initialization logic to configure the files.
 *
 ****************************************************************************/

void weak_function files_initialize(void);

/****************************************************************************
 * Name: files_allocate
 *
 * Description:
 *   Allocate a struct files instance and associate it with an inode instance.
 *   Returns the file descriptor == index into the files array.
 *
 ****************************************************************************/

int files_allocate(FAR struct inode *inode, int oflags, off_t pos, int minfd);

/****************************************************************************
 * Name: files_close
 *
 * Description:
 *   Close an inode (if open)
 *
 * Assumuptions:
 *   Caller holds the list semaphore because the file descriptor will be freed.
 *
 ****************************************************************************/

int files_close(int fd);

/****************************************************************************
 * Name: files_release
 *
 * Assumuptions:
 *   Similar to files_close().  Called only from open() logic on error
 *   conditions.
 *
 ****************************************************************************/

void files_release(int fd);

#undef EXTERN
#if defined(__cplusplus)
}
#endif

#endif /* __FS_INODE_H */