128 lines
3.8 KiB
C
128 lines
3.8 KiB
C
/****************************************************************************
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* libs/libc/unistd/lib_getcwd.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/types.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <errno.h>
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#include "libc.h"
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#ifndef CONFIG_DISABLE_ENVIRON
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: getcwd
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*
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* Description:
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* getcwd() function places the absolute pathname of the current working
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* directory in the array pointed to by 'buf', and returns 'buf.' The
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* pathname copied to the array shall contain no components that are
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* symbolic links. The 'size' argument is the size in bytes of the
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* character array pointed to by the 'buf' argument.
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*
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* As an extension to the POSIX.1-2001 standard, getcwd() allocates
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* the buffer dynamically using lib_malloc if buf is NULL. In this case,
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* the allocated buffer has the length size unless size is zero, when buf
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* is allocated as big as necessary. The caller should free the
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* returned buffer.
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*
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* Input Parameters:
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* buf - a pointer to the location in which the current working directory
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* pathname is returned.
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* size - The size in bytes available at 'buf'
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*
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* Returned Value:
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* Upon successful completion, getcwd() returns the 'buf' argument.
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* Otherwise, getcwd() returns a null pointer and sets errno to indicate
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* the error:
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*
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* EINVAL
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* The 'size' argument is 0 and the 'buf' argument is not NULL.
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* ERANGE
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* The size argument is greater than 0, but is smaller than the length
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* of the current working directory pathname +1.
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* EACCES
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* Read or search permission was denied for a component of the pathname.
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* ENOMEM
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* Insufficient storage space is available.
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*
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****************************************************************************/
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FAR char *getcwd(FAR char *buf, size_t size)
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{
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char *pwd;
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/* Verify input parameters */
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if (buf && size == 0)
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{
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set_errno(EINVAL);
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return NULL;
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}
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if (size == 0)
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{
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size = PATH_MAX + 1;
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}
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/* If no working directory is defined, then default to the home directory */
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pwd = getenv("PWD");
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if (pwd == NULL)
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{
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pwd = CONFIG_LIBC_HOMEDIR;
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}
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/* Verify that the cwd will fit into the user-provided buffer */
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if (strlen(pwd) + 1 > size)
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{
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set_errno(ERANGE);
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return NULL;
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}
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if (buf == NULL)
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{
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buf = lib_malloc(size);
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if (!buf)
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{
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set_errno(ENOMEM);
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return NULL;
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}
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}
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/* Copy the cwd to the user buffer */
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strlcpy(buf, pwd, size);
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return buf;
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}
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#endif /* !CONFIG_DISABLE_ENVIRON */
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