143 lines
4.6 KiB
C
143 lines
4.6 KiB
C
/****************************************************************************
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* fs/vfs/fs_readlink.c
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*
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* Copyright (C) 2017 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT will THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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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/types.h>
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#include <stdbool.h>
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#include <string.h>
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#include <assert.h>
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#include <errno.h>
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#include <nuttx/fs/fs.h>
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#include "inode/inode.h"
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#ifdef CONFIG_PSEUDOFS_SOFTLINKS
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: mkdir
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*
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* Description:
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* The readlink() function will place the contents of the symbolic link
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* referred to by 'path' in the buffer 'buf' which has size 'bufsize'. If
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* the number of bytes in the symbolic link is less than bufsize, the
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* contents of the remainder of 'buf' are unspecified. If the buf argument
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* is not large enough to contain the link content, the first bufsize bytes
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* will be placed in buf. If the value of bufsize is greater than
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* {SSIZE_MAX}, the result is implementation-defined. *
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*
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* Input Parameters:
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* path - The full path to the symbolic link
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* buf - The user-provided buffer in which to return the path to the
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* link target.
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* bufixe - The size of 'buf'
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*
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* Returned Value:
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* Upon successful completion, readlink() will return the count of bytes
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* placed in the buffer. Otherwise, it will return a value of -1, leave the
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* buffer unchanged, and set errno to indicate the error.
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*
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****************************************************************************/
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ssize_t readlink(FAR const char *path, FAR char *buf, size_t bufsize)
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{
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struct inode_search_s desc;
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FAR struct inode *node;
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int errcode;
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int ret;
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DEBUGASSERT(path != NULL && buf != NULL && bufsize > 0);
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/* Find the inode that includes this path (without derefencing the final)
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* symbolic link node.
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*/
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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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errcode = -ret;
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goto errout_with_search;
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}
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/* Get the search results */
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node = desc.node;
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DEBUGASSERT(node != NULL);
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/* An inode was found that includes this path and possibly refers to a
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* symbolic link.
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*
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* Check if the inode is a valid symbolic link.
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*/
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if (!INODE_IS_SOFTLINK(node))
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{
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errcode = EINVAL;
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goto errout_with_inode;
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}
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/* Copy the link target pathto the user-provided buffer. */
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*buf = '\0';
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(void)strncpy(buf, node->u.i_link, bufsize);
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/* Release our reference on the inode and return the length */
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inode_release(node);
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RELEASE_SEARCH(&desc);
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return strlen(buf);
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errout_with_inode:
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inode_release(node);
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errout_with_search:
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RELEASE_SEARCH(&desc);
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set_errno(errcode);
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return ERROR;
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}
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#endif /* CONFIG_PSEUDOFS_SOFTLINKS */
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