b598ab43d7
specified here: https://pubs.opengroup.org/onlinepubs/009695399/functions/lstat.html Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com> Change-Id: Iefc23a02d425ff84fa4027aea7da1181b01eced7
433 lines
14 KiB
C
433 lines
14 KiB
C
/****************************************************************************
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* fs/inode/inode.h
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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#ifndef __FS_INODE_H
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#define __FS_INODE_H
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <nuttx/compiler.h>
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#include <sys/types.h>
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#include <stdint.h>
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#include <stdbool.h>
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#include <dirent.h>
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#include <nuttx/kmalloc.h>
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#include <nuttx/fs/fs.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#ifdef CONFIG_PSEUDOFS_SOFTLINKS
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# define SETUP_SEARCH(d,p,n) \
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do \
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{ \
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(d)->path = (p); \
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(d)->node = NULL; \
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(d)->peer = NULL; \
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(d)->parent = NULL; \
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(d)->relpath = NULL; \
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(d)->linktgt = NULL; \
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(d)->buffer = NULL; \
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(d)->nofollow = (n); \
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} \
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while (0)
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# define RELEASE_SEARCH(d) \
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if ((d)->buffer != NULL) \
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{ \
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kmm_free((d)->buffer); \
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(d)->buffer = NULL; \
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}
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#else
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# define SETUP_SEARCH(d,p,n) \
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do \
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{ \
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(d)->path = (p); \
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(d)->node = NULL; \
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(d)->peer = NULL; \
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(d)->parent = NULL; \
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(d)->relpath = NULL; \
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} \
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while (0)
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# define RELEASE_SEARCH(d)
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#endif
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/****************************************************************************
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* Public Types
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****************************************************************************/
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/* This is the type of the argument to inode_search().
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*
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* path - INPUT: Path of inode to find
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* OUTPUT: Residual part of path not traversed
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* node - INPUT: (not used)
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* OUTPUT: On success, holds the pointer to the inode found.
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* peer - INPUT: (not used)
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* OUTPUT: The inode to the "left" of the inode found.
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* parent - INPUT: (not used)
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* OUTPUT: The inode to the "above" of the inode found.
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* relpath - INPUT: (not used)
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* OUTPUT: If the returned inode is a mountpoint, this is the
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* relative path from the mountpoint.
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* linktgt - INPUT: (not used)
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* OUTPUT: If a symobolic link into a mounted file system is
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* detected while traversing the path, then the link
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* will be converted to a mountpoint inode if the
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* mountpoint link is in an intermediate node of the
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* path or at the final node of the path with
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* nofollow=true.
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* nofollow - INPUT: true: terminal node is returned; false: if the
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* terminal is a soft link, then return the inode of
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* the link target.
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* - OUTPUT: (not used)
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* buffer - INPUT: Not used
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* - OUTPUT: May hold an allocated intermediate path which is
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* probably of no interest to the caller unless it holds
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* the relpath.
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*/
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struct inode_search_s
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{
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FAR const char *path; /* Path of inode to find */
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FAR struct inode *node; /* Pointer to the inode found */
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FAR struct inode *peer; /* Node to the "left" for the found inode */
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FAR struct inode *parent; /* Node "above" the found inode */
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FAR const char *relpath; /* Relative path into the mountpoint */
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#ifdef CONFIG_PSEUDOFS_SOFTLINKS
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FAR const char *linktgt; /* Target of symbolic link if linked to a directory */
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FAR char *buffer; /* Path expansion buffer */
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bool nofollow; /* true: Don't follow terminal soft link */
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#endif
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};
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/* Callback used by foreach_inode to traverse all inodes in the pseudo-
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* file system.
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*/
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typedef int (*foreach_inode_t)(FAR struct inode *node,
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FAR char dirpath[PATH_MAX],
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FAR void *arg);
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/****************************************************************************
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* Public Data
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****************************************************************************/
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#undef EXTERN
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#if defined(__cplusplus)
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#define EXTERN extern "C"
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extern "C"
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{
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#else
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#define EXTERN extern
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#endif
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EXTERN FAR struct inode *g_root_inode;
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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/****************************************************************************
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* Name: inode_initialize
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*
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* Description:
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* This is called from the OS initialization logic to configure the file
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* system.
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*
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****************************************************************************/
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void inode_initialize(void);
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/****************************************************************************
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* Name: inode_semtake
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*
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* Description:
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* Get exclusive access to the in-memory inode tree (tree_sem).
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*
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****************************************************************************/
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int inode_semtake(void);
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/****************************************************************************
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* Name: inode_semgive
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*
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* Description:
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* Relinquish exclusive access to the in-memory inode tree (tree_sem).
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*
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****************************************************************************/
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void inode_semgive(void);
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/****************************************************************************
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* Name: inode_checkflags
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*
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* Description:
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* Check if the access described by 'oflags' is supported on 'inode'
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*
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****************************************************************************/
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int inode_checkflags(FAR struct inode *inode, int oflags);
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/****************************************************************************
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* Name: inode_search
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*
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* Description:
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* Find the inode associated with 'path' returning the inode references
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* and references to its companion nodes.
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*
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* If a mountpoint is encountered in the search prior to encountering the
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* terminal node, the search will terminate at the mountpoint inode. That
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* inode and the relative path from the mountpoint, 'relpath' will be
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* returned.
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*
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* inode_search will follow soft links in path leading up to the terminal
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* node. Whether or no inode_search() will deference that terminal node
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* depends on the 'nofollow' input.
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*
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* If a soft link is encountered that is not the terminal node in the path,
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* that link WILL be deferenced unconditionally.
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*
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* Assumptions:
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* The caller holds the g_inode_sem semaphore
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*
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****************************************************************************/
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int inode_search(FAR struct inode_search_s *desc);
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/****************************************************************************
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* Name: inode_find
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*
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* Description:
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* This is called from the open() logic to get a reference to the inode
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* associated with a path. This is accomplished by calling inode_search().
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* inode_find() is a simple wrapper around inode_search(). The primary
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* difference between inode_find() and inode_search is that inode_find()
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* will lock the inode tree and increment the reference count on the inode.
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*
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****************************************************************************/
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int inode_find(FAR struct inode_search_s *desc);
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/****************************************************************************
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* Name: inode_stat
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*
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* Description:
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* The inode_stat() function will obtain information about an 'inode' in
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* the pseudo file system and will write it to the area pointed to by
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* 'buf'.
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*
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* The 'buf' argument is a pointer to a stat structure, as defined in
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* <sys/stat.h>, into which information is placed concerning the file.
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*
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* Input Parameters:
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* inode - The inode of interest
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* buf - The caller provide location in which to return information
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* about the inode.
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* resolve - Whether to resolve the symbolic link
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*
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* Returned Value:
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* Zero (OK) returned on success. Otherwise, a negated errno value is
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* returned to indicate the nature of the failure.
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*
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****************************************************************************/
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struct stat; /* Forward reference */
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int inode_stat(FAR struct inode *inode, FAR struct stat *buf, int resolve);
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/****************************************************************************
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* Name: inode_free
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*
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* Description:
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* Free resources used by an inode
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*
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****************************************************************************/
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void inode_free(FAR struct inode *node);
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/****************************************************************************
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* Name: inode_nextname
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*
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* Description:
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* Given a path with node names separated by '/', return the next node
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* name.
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*
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****************************************************************************/
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const char *inode_nextname(FAR const char *name);
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/****************************************************************************
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* Name: inode_reserve
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*
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* Description:
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* Reserve an (initialized) inode the pseudo file system.
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*
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* NOTE: Caller must hold the inode semaphore
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*
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* Input Parameters:
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* path - The path to the inode to create
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* inode - The location to return the inode pointer
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*
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* Returned Value:
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* Zero on success (with the inode point in 'inode'); A negated errno
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* value is returned on failure:
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*
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* EINVAL - 'path' is invalid for this operation
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* EEXIST - An inode already exists at 'path'
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* ENOMEM - Failed to allocate in-memory resources for the operation
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*
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****************************************************************************/
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int inode_reserve(FAR const char *path, FAR struct inode **inode);
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/****************************************************************************
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* Name: inode_unlink
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*
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* Description:
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* Given a path, remove a the node from the in-memory, inode tree that the
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* path refers to. This is normally done in preparation to removing or
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* moving an inode.
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*
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* Assumptions/Limitations:
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* The caller must hold the inode semaphore
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*
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****************************************************************************/
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FAR struct inode *inode_unlink(FAR const char *path);
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/****************************************************************************
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* Name: inode_remove
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*
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* Description:
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* Given a path, remove a the node from the in-memory, inode tree that the
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* path refers to and free all resources related to the inode. If the
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* inode is in-use, then it will be unlinked, but will not be freed until
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* the last reference to the inode is released.
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*
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* Assumptions/Limitations:
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* The caller must hold the inode semaphore
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*
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****************************************************************************/
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int inode_remove(FAR const char *path);
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/****************************************************************************
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* Name: inode_addref
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*
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* Description:
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* Increment the reference count on an inode (as when a file descriptor
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* is dup'ed).
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*
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****************************************************************************/
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int inode_addref(FAR struct inode *inode);
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/****************************************************************************
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* Name: inode_release
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*
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* Description:
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* This is called from close() logic when it no longer refers to the inode.
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*
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****************************************************************************/
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void inode_release(FAR struct inode *inode);
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/****************************************************************************
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* Name: foreach_inode
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*
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* Description:
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* Visit each inode in the pseudo-file system. The traversal is terminated
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* when the callback 'handler' returns a non-zero value, or when all of
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* the inodes have been visited.
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*
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* NOTE 1: Use with caution... The pseudo-file system is locked throughout
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* the traversal.
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* NOTE 2: The search algorithm is recursive and could, in principle, use
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* an indeterminate amount of stack space. This will not usually be a
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* real work issue.
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*
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****************************************************************************/
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int foreach_inode(foreach_inode_t handler, FAR void *arg);
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/****************************************************************************
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* Name: files_initialize
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*
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* Description:
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* This is called from the FS initialization logic to configure the files.
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*
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****************************************************************************/
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void weak_function files_initialize(void);
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/****************************************************************************
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* Name: files_allocate
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*
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* Description:
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* Allocate a struct files instance and associate it with an inode
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* instance. Returns the file descriptor == index into the files array.
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*
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****************************************************************************/
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int files_allocate(FAR struct inode *inode, int oflags, off_t pos,
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int minfd);
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/****************************************************************************
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* Name: files_close
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*
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* Description:
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* Close an inode (if open)
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*
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* Assumptions:
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* Caller holds the list semaphore because the file descriptor will be
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* freed.
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*
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****************************************************************************/
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int files_close(int fd);
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/****************************************************************************
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* Name: files_release
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*
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* Assumptions:
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* Similar to files_close(). Called only from open() logic on error
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* conditions.
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*
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****************************************************************************/
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void files_release(int fd);
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#undef EXTERN
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#if defined(__cplusplus)
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}
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#endif
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#endif /* __FS_INODE_H */
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