144 lines
4.4 KiB
C
144 lines
4.4 KiB
C
/****************************************************************************
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* fs/nxffs/nxffs_truncate.c
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*
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* Copyright (C) 2018 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* References: Linux/Documentation/filesystems/romfs.txt
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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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 <fcntl.h>
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#include <assert.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/semaphore.h>
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#include "nxffs.h"
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#ifdef __NO_TRUNCATE_SUPPORT__
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxffs_truncate
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*
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* Description:
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* Set the length of the open, regular file associated with the file
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* structure 'filep' to 'length'.
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*
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****************************************************************************/
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int nxffs_truncate(FAR struct file *filep, off_t length)
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{
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FAR struct nxffs_volume_s *volume;
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FAR struct nxffs_wrfile_s *wrfile;
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off_t oldsize;
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int ret;
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finfo("Write %d bytes to offset %d\n", buflen, filep->f_pos);
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/* Sanity checks */
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DEBUGASSERT(filep->f_priv != NULL && filep->f_inode != NULL);
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/* Recover the open file state from the struct file instance */
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wrfile = (FAR struct nxffs_wrfile_s *)filep->f_priv;
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/* Recover the volume state from the open file */
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volume = (FAR struct nxffs_volume_s *)filep->f_inode->i_private;
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DEBUGASSERT(volume != NULL);
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/* Get exclusive access to the volume. Note that the volume exclsem
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* protects the open file list.
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*/
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ret = nxsem_wait(&volume->exclsem);
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if (ret < 0)
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{
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ferr("ERROR: nxsem_wait failed: %d\n", ret);
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goto errout;
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}
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/* Check if the file was opened with write access */
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if ((wrfile->ofile.oflags & O_WROK) == 0)
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{
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ferr("ERROR: File not open for write access\n");
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ret = -EACCES;
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goto errout_with_semaphore;
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}
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/* Are we shrinking the file? Or extending it? */
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oldsize = wrfile->ofile.entry.datlen;
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if (oldsize == length)
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{
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ret = OK;
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goto errout_with_semaphore;
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}
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else if (oldsize > length)
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{
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/* We are shrinking the file.
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*
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* REVISIT: Logic to shrink the file has not yet been implemented.
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*/
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ret = -ENOSYS;
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}
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else
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{
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/* We are zero-extending the file. This essential amount to a write-
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* append operation with zero data.
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*/
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ret = nxffs_wrextend(volume, wrfile, length);
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}
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errout_with_semaphore:
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nxsem_post(&volume->exclsem);
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errout:
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return ret;
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}
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#endif /* __NO_TRUNCATE_SUPPORT__ */
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