incubator-nuttx/fs/inode/inode.h

447 lines
15 KiB
C

/****************************************************************************
* fs/inode/inode.h
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
#ifndef __FS_INODE_INODE_H
#define __FS_INODE_INODE_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/compiler.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <dirent.h>
#include <sched.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include <nuttx/lib/lib.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define SETUP_SEARCH(d,p,n) \
do \
{ \
(d)->path = (p); \
(d)->node = NULL; \
(d)->peer = NULL; \
(d)->parent = NULL; \
(d)->relpath = NULL; \
(d)->buffer = NULL; \
(d)->nofollow = (n); \
} \
while (0)
#define RELEASE_SEARCH(d) \
do \
{ \
if ((d)->buffer != NULL) \
{ \
lib_free((d)->buffer); \
(d)->buffer = NULL; \
} \
} \
while (0)
#if CONFIG_FS_BACKTRACE > 0
# define FS_ADD_BACKTRACE(filep) \
do \
{ \
int n = sched_backtrace(_SCHED_GETTID(), \
(filep)->f_backtrace, \
CONFIG_FS_BACKTRACE, \
CONFIG_FS_BACKTRACE_SKIP); \
if (n < CONFIG_FS_BACKTRACE) \
{ \
(filep)->f_backtrace[n] = NULL; \
} \
} \
while (0)
#else
# define FS_ADD_BACKTRACE(filep)
#endif
/****************************************************************************
* Public Types
****************************************************************************/
/* This is the type of the argument to inode_search().
*
* path - INPUT: Path of inode to find
* OUTPUT: Residual part of path not traversed
* node - INPUT: (not used)
* OUTPUT: On success, holds the pointer to the inode found.
* peer - INPUT: (not used)
* OUTPUT: The inode to the "left" of the inode found.
* parent - INPUT: (not used)
* OUTPUT: The inode to the "above" of the inode found.
* relpath - INPUT: (not used)
* OUTPUT: If the returned inode is a mountpoint, this is the
* relative path from the mountpoint.
* OUTPUT: If a symobolic link into a mounted file system is
* detected while traversing the path, then the link
* will be converted to a mountpoint inode if the
* mountpoint link is in an intermediate node of the
* path or at the final node of the path with
* nofollow=true.
* nofollow - INPUT: true: terminal node is returned; false: if the
* terminal is a soft link, then return the inode of
* the link target.
* - OUTPUT: (not used)
* buffer - INPUT: Not used
* - OUTPUT: May hold an allocated intermediate path which is
* probably of no interest to the caller unless it holds
* the relpath.
*/
struct inode_search_s
{
FAR const char *path; /* Path of inode to find */
FAR struct inode *node; /* Pointer to the inode found */
FAR struct inode *peer; /* Node to the "left" for the found inode */
FAR struct inode *parent; /* Node "above" the found inode */
FAR const char *relpath; /* Relative path into the mountpoint */
FAR char *buffer; /* Path expansion buffer */
bool nofollow; /* true: Don't follow terminal soft link */
};
/* 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_lock
*
* Description:
* Get exclusive access to the in-memory inode tree (tree_sem).
*
****************************************************************************/
int inode_lock(void);
/****************************************************************************
* Name: inode_unlock
*
* Description:
* Relinquish exclusive access to the in-memory inode tree (tree_sem).
*
****************************************************************************/
void inode_unlock(void);
/****************************************************************************
* Name: inode_search
*
* Description:
* Find the inode associated with 'path' returning the inode references
* and references to its companion nodes.
*
* If a mountpoint is encountered in the search prior to encountering the
* terminal node, the search will terminate at the mountpoint inode. That
* inode and the relative path from the mountpoint, 'relpath' will be
* returned.
*
* inode_search will follow soft links in path leading up to the terminal
* node. Whether or no inode_search() will deference that terminal node
* depends on the 'nofollow' input.
*
* If a soft link is encountered that is not the terminal node in the path,
* that link WILL be deferenced unconditionally.
*
* Assumptions:
* The caller holds the g_inode_sem semaphore
*
****************************************************************************/
int inode_search(FAR struct inode_search_s *desc);
/****************************************************************************
* Name: inode_find
*
* Description:
* This is called from the open() logic to get a reference to the inode
* associated with a path. This is accomplished by calling inode_search().
* inode_find() is a simple wrapper around inode_search(). The primary
* difference between inode_find() and inode_search is that inode_find()
* will lock the inode tree and increment the reference count on the inode.
*
****************************************************************************/
int inode_find(FAR struct inode_search_s *desc);
/****************************************************************************
* Name: inode_stat
*
* Description:
* The inode_stat() function will obtain information about an 'inode' in
* the pseudo file system and will write it to the area pointed to by
* 'buf'.
*
* The 'buf' argument is a pointer to a stat structure, as defined in
* <sys/stat.h>, into which information is placed concerning the file.
*
* Input Parameters:
* inode - The inode of interest
* buf - The caller-provided location in which to return information
* about the inode.
* resolve - Whether to resolve the symbolic link:
* 0: Don't resolve the symbolic line
* 1: Resolve the symbolic link
* >=2: The recursive count in the resolving process
*
* Returned Value:
* Zero (OK) returned on success. Otherwise, a negated errno value is
* returned to indicate the nature of the failure.
*
****************************************************************************/
int inode_stat(FAR struct inode *inode, FAR struct stat *buf, int resolve);
/****************************************************************************
* Name: inode_chstat
*
* Description:
* The inode_chstat() function will change information about an 'inode'
* in the pseudo file system according the area pointed to by 'buf'.
*
* The 'buf' argument is a pointer to a stat structure, as defined in
* <sys/stat.h>, which information is placed concerning the file.
*
* Input Parameters:
* inode - The inode of interest
* buf - The caller provide location in which to apply information
* about the inode.
* flags - The valid field in buf
* resolve - Whether to resolve the symbolic link
*
* Returned Value:
* Zero (OK) returned on success. Otherwise, a negated errno value is
* returned to indicate the nature of the failure.
*
****************************************************************************/
int inode_chstat(FAR struct inode *inode,
FAR const struct stat *buf, int flags, int resolve);
/****************************************************************************
* Name: inode_getpath
*
* Description:
* Given the full path from inode.
*
****************************************************************************/
int inode_getpath(FAR struct inode *node, FAR char *path, size_t len);
/****************************************************************************
* 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_root_reserve
*
* Description:
* Reserve the root node for the pseudo file system.
*
****************************************************************************/
void inode_root_reserve(void);
/****************************************************************************
* 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
* mode - inmode privileges
* 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,
mode_t mode, FAR struct inode **inode);
/****************************************************************************
* 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_addref
*
* Description:
* Increment the reference count on an inode (as when a file descriptor
* is dup'ed).
*
****************************************************************************/
int 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 indeterminate amount of stack space. This will not usually be a
* real work issue.
*
****************************************************************************/
int foreach_inode(foreach_inode_t handler, FAR void *arg);
/****************************************************************************
* Name: dir_allocate
*
* Description:
* Allocate a directory instance and bind it to f_priv of filep.
*
****************************************************************************/
int dir_allocate(FAR struct file *filep, FAR const char *relpath);
/****************************************************************************
* Name: pseudofile_create
*
* Description:
* Create the pseudo-file with specified path and mode, and alloc inode
* of this pseudo-file.
*
****************************************************************************/
#ifdef CONFIG_PSEUDOFS_FILE
int pseudofile_create(FAR struct inode **node, FAR const char *path,
mode_t mode);
#endif
/****************************************************************************
* Name: inode_is_pseudofile
*
* Description:
* Check inode whether is a pseudo file.
*
****************************************************************************/
#ifdef CONFIG_PSEUDOFS_FILE
bool inode_is_pseudofile(FAR struct inode *inode);
#endif
#undef EXTERN
#if defined(__cplusplus)
}
#endif
#endif /* __FS_INODE_INODE_H */