b5d4a01821
Gregory Nutt has submitted the SGA and we can migrate the licenses to Apache. Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
120 lines
4.1 KiB
C
120 lines
4.1 KiB
C
/****************************************************************************
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* libs/libc/unistd/lib_truncate.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 <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <assert.h>
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#ifndef CONFIG_DISABLE_MOUNTPOINT
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: truncate
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*
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* Description:
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* The truncate() function causes the regular file named by path to have
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* a size of length bytes.
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*
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* If the file previously was larger than length, the extra data is
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* discarded. If it was previously shorter than length, it is unspecified
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* whether the file is changed or its size increased. If the file is
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* extended, the extended area appears as if it were zero-filled.
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* With truncate(), the file must be open for writing; for truncate(),
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* the process must have write permission for the file.
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*
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* truncate() does not modify the file offset for any open file
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* descriptions associated with the file.
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*
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* Input Parameters:
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* path - The path to the regular file to be truncated.
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* length - The new length of the regular file.
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*
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* Returned Value:
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* Upon successful completion, truncate() return 0s. Otherwise a -1 is
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* returned, and errno is set to indicate the error.
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* EINTR
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* - A signal was caught during execution.
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* EINVAL
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* - The length argument was less than 0.
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* EFBIG or EINVAL
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* - The length argument was greater than the maximum file size.
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* EIO
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* - An I/O error occurred while reading from or writing to a file
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* system.
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* EACCES
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* - A component of the path prefix denies search permission, or write
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* permission is denied on the file.
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* EISDIR
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* - The named file is a directory.
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* ELOOP
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* - Too many symbolic links were encountered in resolving path.
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* ENAMETOOLONG
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* - The length of the specified pathname exceeds PATH_MAX bytes, or
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* the length of a component of the pathname exceeds NAME_MAX bytes.
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* ENOENT
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* - A component of path does not name an existing file or path is an
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* empty string.
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* ENOTDIR
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* - A component of the path prefix of path is not a directory.
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* EROFS
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* - he named file resides on a read-only file system.
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* ENAMETOOLONG
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* - Pathname resolution of a symbolic link produced an intermediate
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* result whose length exceeds PATH_MAX.
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*
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****************************************************************************/
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int truncate(FAR const char *path, off_t length)
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{
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int fd;
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int ret;
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DEBUGASSERT(path != NULL && length >= 0);
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/* Open the regular file at 'path' for write-only access */
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fd = open(path, O_WRONLY);
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if (fd < 0)
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{
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return ERROR;
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}
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/* Then let ftruncate() do the work */
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ret = ftruncate(fd, length);
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close(fd);
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return ret;
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}
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#endif /* !CONFIG_DISABLE_MOUNTPOINT */
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