465 lines
12 KiB
C
465 lines
12 KiB
C
/****************************************************************************
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* fs/vfs/fs_stat.c
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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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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/stat.h>
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#include <stdbool.h>
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#include <string.h>
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#include <sched.h>
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#include <assert.h>
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#include <errno.h>
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#include "inode/inode.h"
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#include <nuttx/mtd/mtd.h>
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#include <nuttx/fs/ioctl.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#define RESET_BUF(b) memset((b), 0, sizeof(struct stat));
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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static int stat_recursive(FAR const char *path,
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FAR struct stat *buf, int resolve);
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: stat_recursive
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*
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* Input Parameters:
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* path - The inode of interest
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* buf - The caller-provided 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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* 0: Don't resolve the symbolic line
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* 1: Resolve the symbolic link
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* >=2: The recursive count in the resolving process
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*
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* Returned Value:
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* Zero on success; < 0 on failure:
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*
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* EACCES Search permission is denied for one of the directories in the
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* path prefix of path.
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* EFAULT Bad address.
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* ENOENT A component of the path path does not exist, or the path is an
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* empty string.
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* ENOMEM Out of memory
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* ENOTDIR A component of the path is not a directory.
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*
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****************************************************************************/
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static int stat_recursive(FAR const char *path,
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FAR struct stat *buf, int resolve)
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{
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struct inode_search_s desc;
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FAR struct inode *inode;
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int ret;
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/* Get an inode for this path */
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SETUP_SEARCH(&desc, path, true);
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ret = inode_find(&desc);
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if (ret < 0)
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{
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/* This name does not refer to an inode in the pseudo file system and
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* there is no mountpoint that includes in this path.
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*/
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goto errout_with_search;
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}
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/* Get the search results */
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inode = desc.node;
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DEBUGASSERT(inode != NULL);
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/* The way we handle the stat depends on the type of inode that we
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* are dealing with.
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*/
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#ifndef CONFIG_DISABLE_MOUNTPOINT
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if (INODE_IS_MOUNTPT(inode))
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{
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/* The node is a file system mointpoint. Verify that the mountpoint
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* supports the stat() method
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*/
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if (inode->u.i_mops && inode->u.i_mops->stat)
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{
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/* Perform the stat() operation */
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ret = inode->u.i_mops->stat(inode, desc.relpath, buf);
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}
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else
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{
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ret = -ENOSYS;
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}
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}
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else
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#endif
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{
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/* The node is part of the root pseudo file system. This path may
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* recurse if soft links are supported in the pseudo file system.
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*/
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ret = inode_stat(inode, buf, resolve);
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}
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inode_release(inode);
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errout_with_search:
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RELEASE_SEARCH(&desc);
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return ret;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nx_stat
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*
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* Description:
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* nx_stat() is similar to the standard 'stat' interface except that is
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* not a cancellation point and it does not modify the errno variable.
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*
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* nx_stat() is an internal NuttX interface and should not be called from
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* applications.
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*
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* Returned Value:
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* Zero is returned on success; a negated value is returned on any failure.
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*
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****************************************************************************/
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int nx_stat(FAR const char *path, FAR struct stat *buf, int resolve)
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{
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/* Sanity checks */
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if (path == NULL || buf == NULL)
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{
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return -EFAULT;
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}
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if (*path == '\0')
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{
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return -ENOENT;
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}
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/* The perform the stat() operation on the path. This is potentially
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* recursive if soft link support is enabled.
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*/
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return stat_recursive(path, buf, resolve);
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}
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/****************************************************************************
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* Name: stat
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*
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* Returned Value:
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* Zero on success; -1 on failure with errno set:
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*
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* EACCES Search permission is denied for one of the directories in the
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* path prefix of path.
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* EFAULT Bad address.
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* ENOENT A component of the path path does not exist, or the path is an
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* empty string.
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* ENOMEM Out of memory
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* ENOTDIR A component of the path is not a directory.
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*
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****************************************************************************/
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int stat(FAR const char *path, FAR struct stat *buf)
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{
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int ret;
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ret = nx_stat(path, buf, 1);
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if (ret < 0)
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{
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set_errno(-ret);
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ret = ERROR;
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}
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return ret;
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}
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int lstat(FAR const char *path, FAR struct stat *buf)
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{
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int ret;
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ret = nx_stat(path, buf, 0);
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if (ret < 0)
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{
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set_errno(-ret);
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ret = ERROR;
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}
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return ret;
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}
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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 write it to the area pointed to by '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-provided 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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* 0: Don't resolve the symbolic line
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* 1: Resolve the symbolic link
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* >=2: The recursive count in the resolving process
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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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int inode_stat(FAR struct inode *inode, FAR struct stat *buf, int resolve)
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{
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DEBUGASSERT(inode != NULL && buf != NULL);
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/* Most of the stat entries just do not apply */
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RESET_BUF(buf);
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/* Handle "special" nodes */
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#if defined(CONFIG_FS_NAMED_SEMAPHORES)
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/* Check for a named semaphore */
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if (INODE_IS_NAMEDSEM(inode))
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{
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buf->st_mode = S_IFSEM;
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}
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else
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#endif
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#if !defined(CONFIG_DISABLE_MQUEUE) || !defined(CONFIG_DISABLE_MQUEUE_SYSV)
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/* Check for a message queue */
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if (INODE_IS_MQUEUE(inode))
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{
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buf->st_mode = S_IFMQ;
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}
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else
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#endif
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#if defined(CONFIG_FS_SHMFS)
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/* Check for shared memory */
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if (INODE_IS_SHM(inode))
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{
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buf->st_mode = S_IFSHM;
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buf->st_size = inode->i_size;
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}
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else
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#endif
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#if defined(CONFIG_MTD)
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/* Check for an MTD driver */
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if (INODE_IS_MTD(inode))
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{
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struct mtd_geometry_s mtdgeo;
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buf->st_mode = S_IFMTD;
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buf->st_mode |= S_IROTH | S_IRGRP | S_IRUSR;
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buf->st_mode |= S_IWOTH | S_IWGRP | S_IWUSR;
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if (inode->u.i_mtd != NULL &&
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MTD_IOCTL(inode->u.i_mtd, MTDIOC_GEOMETRY,
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(unsigned long)((uintptr_t)&mtdgeo)) >= 0)
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{
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buf->st_size = mtdgeo.neraseblocks * mtdgeo.erasesize;
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}
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}
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else
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#endif
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#ifdef CONFIG_PSEUDOFS_SOFTLINKS
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/* Handle softlinks differently. Just call stat() recursively on the
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* target of the softlink.
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*
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* REVISIT: This has the possibility of an infinite loop!
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*/
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if (INODE_IS_SOFTLINK(inode))
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{
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if (resolve)
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{
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int ret;
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/* Increment the link counter. This is necessary to avoid
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* infinite recursion if loops are encountered in the
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* traversal. If we encounter more SYMLOOP_MAX symbolic links
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* at any time during the traversal, error out.
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*
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* NOTE: That inode_search() will automatically skip over
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* consecutive, intermediate symbolic links. Those numbers
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* will not be included in the total.
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*/
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if (resolve > SYMLOOP_MAX)
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{
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return -ELOOP;
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}
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/* stat() the target of the soft link. */
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ret = stat_recursive(inode->u.i_link, buf, ++resolve);
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/* If stat() fails, then there is a problem with the target of
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* the symbolic link, but not with the symbolic link itself.
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* We should still report success, just with less information.
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*/
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if (ret < 0)
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{
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RESET_BUF(buf);
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}
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return ret;
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}
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else
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{
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/* Make sure the caller knows that this is a symbolic link. */
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buf->st_mode = S_IRWXO | S_IRWXG | S_IRWXU | S_IFLNK;
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}
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}
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else
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#endif
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#if defined(CONFIG_PIPES)
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/* Check for pipes */
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if (INODE_IS_PIPE(inode))
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{
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buf->st_mode = S_IRWXO | S_IRWXG | S_IRWXU | S_IFIFO;
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}
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else
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#endif
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/* Handle "normal inodes */
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if (inode->u.i_ops != NULL)
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{
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/* Determine read/write privileges based on the existence of read
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* and write methods.
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*/
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if (inode->u.i_ops->read)
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{
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buf->st_mode = S_IROTH | S_IRGRP | S_IRUSR;
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}
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if (inode->u.i_ops->write)
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{
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buf->st_mode |= S_IWOTH | S_IWGRP | S_IWUSR;
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}
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/* Determine the type of the inode */
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/* Check for a mountpoint and a pseudo dir */
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if (INODE_IS_MOUNTPT(inode) || INODE_IS_PSEUDODIR(inode))
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{
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buf->st_mode |= S_IFDIR;
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}
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/* Check for a block driver */
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else if (INODE_IS_BLOCK(inode))
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{
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/* What is if also has child inodes? */
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buf->st_mode |= S_IFBLK;
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#ifndef CONFIG_DISABLE_MOUNTPOINT
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if ((inode->u.i_bops != NULL) &&
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(inode->u.i_bops->geometry != NULL))
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{
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struct geometry geo;
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if (inode->u.i_bops->geometry(inode, &geo) >= 0 &&
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geo.geo_available)
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{
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buf->st_size = geo.geo_nsectors * geo.geo_sectorsize;
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}
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}
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#endif
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}
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/* Otherwise, the node must refer to a character driver */
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else /* if (INODE_IS_DRIVER(inode)) */
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{
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/* What is it if it also has child inodes? */
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#ifdef CONFIG_PSEUDOFS_FILE
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buf->st_size = inode->i_size;
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if (inode_is_pseudofile(inode))
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{
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buf->st_mode |= S_IFREG;
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}
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else
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#endif
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{
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buf->st_mode |= S_IFCHR;
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}
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}
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}
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else
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{
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/* If it has no operations, then it must just be a intermediate
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* node in the inode tree. It is something like a directory.
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* We'll say that all pseudo-directories are read-able but not
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* write-able.
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*/
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buf->st_mode |= S_IFDIR | S_IROTH | S_IRGRP | S_IRUSR;
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}
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#ifdef CONFIG_PSEUDOFS_ATTRIBUTES
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buf->st_mode |= inode->i_mode;
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buf->st_uid = inode->i_owner;
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buf->st_gid = inode->i_group;
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buf->st_atim = inode->i_atime;
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buf->st_mtim = inode->i_mtime;
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buf->st_ctim = inode->i_ctime;
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#endif
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buf->st_ino = inode->i_ino;
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return OK;
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}
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