e4652bd3dc
fs: Add truncate() support for userfs
fs/unionfs: Add truncate() support to the unionfs
fs/tmpfs: Add ftruncate() support to tmpfs
syscall/: Add system call support for ftruncate()
net/route: Adding ftruncate() support eliminates an issue in file-based routing table management.
fs: Add basic framework to support truncate() and ftruncate(). The infrastructure is complete. Now, however, the actual implementation of ftruncate() will have to be done for each file system.
135 lines
4.9 KiB
C
135 lines
4.9 KiB
C
/****************************************************************************
|
|
* libc/unistd/lib_truncate.c
|
|
*
|
|
* Copyright (C) 2018 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 SHALL 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 <unistd.h>
|
|
#include <fcntl.h>
|
|
#include <errno.h>
|
|
#include <assert.h>
|
|
|
|
#ifndef CONFIG_DISABLE_MOUNTPOINT
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: truncate
|
|
*
|
|
* Description:
|
|
* The truncate() function causes the regular file named by path to have
|
|
* a size of length bytes.
|
|
*
|
|
* If the file previously was larger than length, the extra data is
|
|
* discarded. If it was previously shorter than length, it is unspecified
|
|
* whether the file is changed or its size increased. If the file is
|
|
* extended, the extended area appears as if it were zero-filled.
|
|
|
|
* With truncate(), the file must be open for writing; for truncate(),
|
|
* the process must have write permission for the file.
|
|
*
|
|
* truncate() does not modify the file offset for any open file
|
|
* descriptions associated with the file.
|
|
*
|
|
* Input Parameters:
|
|
* path - The path to the regular file to be truncated.
|
|
* length - The new length of the regular file.
|
|
*
|
|
* Returned Value:
|
|
* Upon successful completion, truncate() return 0s. Otherwise a -1 is
|
|
* returned, and errno is set to indicate the error.
|
|
|
|
* EINTR
|
|
* - A signal was caught during execution.
|
|
* EINVAL
|
|
* - The length argument was less than 0.
|
|
* EFBIG or EINVAL
|
|
* - The length argument was greater than the maximum file size.
|
|
* EIO
|
|
* - An I/O error occurred while reading from or writing to a file
|
|
* system.
|
|
* EACCES
|
|
* - A component of the path prefix denies search permission, or write
|
|
* permission is denied on the file.
|
|
* EISDIR
|
|
* - The named file is a directory.
|
|
* ELOOP
|
|
* - Too many symbolic links were encountered in resolving path.
|
|
* ENAMETOOLONG
|
|
* - The length of the specified pathname exceeds PATH_MAX bytes, or
|
|
* the length of a component of the pathname exceeds NAME_MAX bytes.
|
|
* ENOENT
|
|
* - A component of path does not name an existing file or path is an
|
|
* empty string.
|
|
* ENOTDIR
|
|
* - A component of the path prefix of path is not a directory.
|
|
* EROFS
|
|
* - he named file resides on a read-only file system.
|
|
* ENAMETOOLONG
|
|
* - Pathname resolution of a symbolic link produced an intermediate
|
|
* result whose length exceeds PATH_MAX.
|
|
*
|
|
****************************************************************************/
|
|
|
|
int truncate(FAR const char *path, off_t length)
|
|
{
|
|
int fd;
|
|
int ret;
|
|
|
|
DEBUGASSERT(path != NULL && length >= 0);
|
|
|
|
/* Open the regular file at 'path' for write-only access */
|
|
|
|
fd = open(path, O_WRONLY);
|
|
if (fd < 0)
|
|
{
|
|
return ERROR;
|
|
}
|
|
|
|
/* Then let ftruncate() do the work */
|
|
|
|
ret = ftruncate(fd, length);
|
|
|
|
close(fd);
|
|
return ret;
|
|
}
|
|
|
|
#endif /* !CONFIG_DISABLE_MOUNTPOINT */
|