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- /****************************************************************************
- * fs/vfs/fs_readlink.c
- *
- * Copyright (C) 2017 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 will 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.
- *
- ****************************************************************************/
- /****************************************************************************
- * Included Files
- ****************************************************************************/
- #include <nuttx/config.h>
- #include <sys/types.h>
- #include <stdbool.h>
- #include <string.h>
- #include <assert.h>
- #include <errno.h>
- #include <nuttx/fs/fs.h>
- #include "inode/inode.h"
- #ifdef CONFIG_PSEUDOFS_SOFTLINKS
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: mkdir
- *
- * Description:
- * The readlink() function will place the contents of the symbolic link
- * referred to by 'path' in the buffer 'buf' which has size 'bufsize'. If
- * the number of bytes in the symbolic link is less than bufsize, the
- * contents of the remainder of 'buf' are unspecified. If the buf argument
- * is not large enough to contain the link content, the first bufsize bytes
- * will be placed in buf. If the value of bufsize is greater than
- * {SSIZE_MAX}, the result is implementation-defined. *
- *
- * Input Parameters:
- * path - The full path to the symbolic link
- * buf - The user-provided buffer in which to return the path to the
- * link target.
- * bufixe - The size of 'buf'
- *
- * Returned Value:
- * Upon successful completion, readlink() will return the count of bytes
- * placed in the buffer. Otherwise, it will return a value of -1, leave the
- * buffer unchanged, and set errno to indicate the error.
- *
- ****************************************************************************/
- ssize_t readlink(FAR const char *path, FAR char *buf, size_t bufsize)
- {
- struct inode_search_s desc;
- FAR struct inode *node;
- int errcode;
- int ret;
- DEBUGASSERT(path != NULL && buf != NULL && bufsize > 0);
- /* Find the inode that includes this path (without derefencing the final)
- * symbolic link node.
- */
- SETUP_SEARCH(&desc, path, true);
- ret = inode_find(&desc);
- if (ret < 0)
- {
- errcode = -ret;
- goto errout_with_search;
- }
- /* Get the search results */
- node = desc.node;
- DEBUGASSERT(node != NULL);
- /* An inode was found that includes this path and possibly refers to a
- * symbolic link.
- *
- * Check if the inode is a valid symbolic link.
- */
- if (!INODE_IS_SOFTLINK(node))
- {
- errcode = EINVAL;
- goto errout_with_inode;
- }
- /* Copy the link target pathto the user-provided buffer. */
- *buf = '\0';
- (void)strncpy(buf, node->u.i_link, bufsize);
- /* Release our reference on the inode and return the length */
- inode_release(node);
- RELEASE_SEARCH(&desc);
- return strlen(buf);
- errout_with_inode:
- inode_release(node);
- errout_with_search:
- RELEASE_SEARCH(&desc);
- set_errno(errcode);
- return ERROR;
- }
- #endif /* CONFIG_PSEUDOFS_SOFTLINKS */
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