85 lines
3.1 KiB
C
85 lines
3.1 KiB
C
/****************************************************************************
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* libs/libc/unistd/lib_readlinkat.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 <errno.h>
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#include <unistd.h>
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#include "libc.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: readlinkat
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*
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* Description:
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* The readlinkat() system call operates in exactly the same way as
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* readlink(), except for the differences described here.
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*
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* If the pathname given in pathname is relative, then it is interpreted
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* relative to the directory referred to by the file descriptor dirfd
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* (rather than relative to the current working directory of the calling
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* process)
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*
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* If pathname is relative and dirfd is the special value AT_FDCWD, then
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* pathname is interpreted relative to the current working directory of
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* the calling process (like readlink()).
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*
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* If pathname is absolute, then dirfd is ignored.
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*
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* Input Parameters:
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* dirfd - The file descriptor of directory.
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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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* bufsize - The size of 'buf'
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*
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* Returned Value:
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* Upon successful completion, readlinkat() 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 readlinkat(int dirfd, FAR const char *path, FAR char *buf,
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size_t bufsize)
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{
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char fullpath[PATH_MAX];
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int ret;
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ret = lib_getfullpath(dirfd, path, fullpath, sizeof(fullpath));
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if (ret < 0)
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{
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set_errno(-ret);
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return ERROR;
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}
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return readlink(fullpath, buf, bufsize);
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}
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#endif /* CONFIG_PSEUDOFS_SOFTLINKS */
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