forked from nuttx/nuttx-update
9a2b6be842
No functional changes are expected.
422 lines
13 KiB
C
422 lines
13 KiB
C
/****************************************************************************
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* fs/vfs/fs_write.c
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*
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* SPDX-License-Identifier: Apache-2.0
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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 <unistd.h>
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#include <fcntl.h>
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#include <sched.h>
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#include <errno.h>
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#include <assert.h>
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#include <nuttx/cancelpt.h>
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#include "notify/notify.h"
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#include "inode/inode.h"
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: file_writev_compat
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*
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* Description:
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* Emulate writev using file_operation::write.
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*
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****************************************************************************/
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static ssize_t file_writev_compat(FAR struct file *filep,
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FAR const struct uio *uio)
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{
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FAR const struct iovec *iov = uio->uio_iov;
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int iovcnt = uio->uio_iovcnt;
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FAR struct inode *inode = filep->f_inode;
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ssize_t ntotal;
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ssize_t nwritten;
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size_t remaining;
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FAR uint8_t *buffer;
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int i;
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DEBUGASSERT(inode->u.i_ops->write != NULL);
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/* Process each entry in the struct iovec array */
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for (i = 0, ntotal = 0; i < iovcnt; i++)
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{
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/* Ignore zero-length writes */
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if (iov[i].iov_len == 0)
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{
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continue;
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}
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buffer = iov[i].iov_base;
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remaining = iov[i].iov_len;
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nwritten = inode->u.i_ops->write(filep, (void *)buffer, remaining);
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/* Check for a write error */
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if (nwritten < 0)
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{
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return ntotal ? ntotal : nwritten;
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}
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ntotal += nwritten;
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/* Check for a parital success condition */
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if (nwritten < remaining)
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{
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return ntotal;
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}
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/* Update the pointer */
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buffer += nwritten;
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remaining -= nwritten;
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}
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return ntotal;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: file_writev
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*
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* Description:
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* Equivalent to the standard writev() function except that is accepts a
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* struct file instance instead of a file descriptor. It is functionally
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* equivalent to writev() except that in addition to the differences in
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* input parameters:
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*
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* - It does not modify the errno variable,
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* - It is not a cancellation point, and
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*
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* Input Parameters:
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* filep - Instance of struct file to use with the write
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* uio - User buffer information
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*
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* Returned Value:
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* On success, the number of bytes written are returned (zero indicates
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* nothing was written). On any failure, a negated errno value is returned
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* (see comments withwrite() for a description of the appropriate errno
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* values).
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*
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****************************************************************************/
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ssize_t file_writev(FAR struct file *filep, FAR const struct uio *uio)
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{
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FAR struct inode *inode;
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ssize_t ret = -EBADF;
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/* Was this file opened for write access? */
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if ((filep->f_oflags & O_WROK) == 0)
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{
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return -EACCES;
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}
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/* Is a driver registered? Does it support the write method?
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* If yes, then let the driver perform the write.
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*/
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inode = filep->f_inode;
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if (inode != NULL && inode->u.i_ops)
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{
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if (inode->u.i_ops->writev)
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{
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ret = inode->u.i_ops->writev(filep, uio);
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}
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else if (inode->u.i_ops->write)
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{
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ret = file_writev_compat(filep, uio);
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}
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}
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#ifdef CONFIG_FS_NOTIFY
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if (ret > 0)
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{
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notify_write(filep);
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}
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#endif
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return ret;
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}
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/****************************************************************************
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* Name: file_write
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*
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* Description:
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* Equivalent to the standard write() function except that is accepts a
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* struct file instance instead of a file descriptor. It is functionally
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* equivalent to write() except that in addition to the differences in
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* input parameters:
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*
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* - It does not modify the errno variable,
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* - It is not a cancellation point, and
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*
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* Input Parameters:
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* filep - Instance of struct file to use with the write
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* buf - Data to write
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* nbytes - Length of data to write
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*
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* Returned Value:
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* On success, the number of bytes written are returned (zero indicates
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* nothing was written). On any failure, a negated errno value is returned
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* (see comments withwrite() for a description of the appropriate errno
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* values).
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*
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****************************************************************************/
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ssize_t file_write(FAR struct file *filep, FAR const void *buf,
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size_t nbytes)
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{
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struct iovec iov;
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struct uio uio;
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iov.iov_base = (FAR void *)buf;
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iov.iov_len = nbytes;
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uio.uio_iov = &iov;
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uio.uio_iovcnt = 1;
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return file_writev(filep, &uio);
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}
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/****************************************************************************
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* Name: nx_writev
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*
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* Description:
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* nx_writev() writes up to nytes bytes to the file referenced by the file
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* descriptor fd from the buffer starting at buf. nx_writev() is an
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* internal OS function. It is functionally equivalent to writev() except
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* that:
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*
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* - It does not modify the errno variable, and
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* - It is not a cancellation point.
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*
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* Input Parameters:
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* fd - file descriptor to write to
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* iov - Data to write
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* iovcnt - The number of vectors
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*
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* Returned Value:
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* On success, the number of bytes written are returned (zero indicates
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* nothing was written). On any failure, a negated errno value is returned
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* (see comments withwrite() for a description of the appropriate errno
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* values).
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*
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****************************************************************************/
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ssize_t nx_writev(int fd, FAR const struct iovec *iov, int iovcnt)
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{
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struct uio uio;
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FAR struct file *filep;
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ssize_t ret;
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/* First, get the file structure.
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* Note that fs_getfilep() will return the errno on failure.
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*/
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ret = (ssize_t)fs_getfilep(fd, &filep);
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if (ret >= 0)
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{
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/* Perform the write operation using the file descriptor as an
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* index. Note that file_writev() will return the errno on failure.
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*/
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uio.uio_iov = iov;
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uio.uio_iovcnt = iovcnt;
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ret = file_writev(filep, &uio);
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fs_putfilep(filep);
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}
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return ret;
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}
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/****************************************************************************
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* Name: nx_write
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*
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* Description:
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* nx_write() writes up to nytes bytes to the file referenced by the file
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* descriptor fd from the buffer starting at buf. nx_write() is an
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* internal OS function. It is functionally equivalent to write() except
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* that:
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*
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* - It does not modify the errno variable, and
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* - It is not a cancellation point.
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*
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* Input Parameters:
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* fd - file descriptor to write to
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* buf - Data to write
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* nbytes - Length of data to write
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*
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* Returned Value:
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* On success, the number of bytes written are returned (zero indicates
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* nothing was written). On any failure, a negated errno value is returned
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* (see comments withwrite() for a description of the appropriate errno
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* values).
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*
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****************************************************************************/
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ssize_t nx_write(int fd, FAR const void *buf, size_t nbytes)
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{
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struct iovec iov;
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iov.iov_base = (void *)buf;
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iov.iov_len = nbytes;
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return nx_writev(fd, &iov, 1);
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}
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/****************************************************************************
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* Name: writev
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*
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* Description:
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* writev() writes up to nytes bytes to the file referenced by the file
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* descriptor fd from the buffer starting at buf.
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*
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* Input Parameters:
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* fd - file descriptor to write to
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* iov - Data to write
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* iovcnt - The number of vectors
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*
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* Returned Value:
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* On success, the number of bytes written are returned (zero indicates
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* nothing was written). On error, -1 is returned, and errno is set appro-
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* priately:
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*
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* EAGAIN
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* Non-blocking I/O has been selected using O_NONBLOCK and the write
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* would block.
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* EBADF
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* fd is not a valid file descriptor or is not open for writing.
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* EFAULT
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* buf is outside your accessible address space.
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* EFBIG
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* An attempt was made to write a file that exceeds the implementation
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* defined maximum file size or the process's file size limit, or
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* to write at a position past the maximum allowed offset.
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* EINTR
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* The call was interrupted by a signal before any data was written.
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* EINVAL
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* fd is attached to an object which is unsuitable for writing; or
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* the file was opened with the O_DIRECT flag, and either the address
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* specified in buf, the value specified in count, or the current
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* file offset is not suitably aligned.
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* EIO
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* A low-level I/O error occurred while modifying the inode.
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* ENOSPC
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* The device containing the file referred to by fd has no room for
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* the data.
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* EPIPE
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* fd is connected to a pipe or socket whose reading end is closed.
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* When this happens the writing process will also receive a SIGPIPE
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* signal. (Thus, the write return value is seen only if the program
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* catches, blocks or ignores this signal.)
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*
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****************************************************************************/
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ssize_t writev(int fd, FAR const struct iovec *iov, int iovcnt)
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{
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ssize_t ret;
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/* write() is a cancellation point */
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enter_cancellation_point();
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/* Let nx_writev() do all of the work */
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ret = nx_writev(fd, iov, iovcnt);
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if (ret < 0)
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{
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set_errno(-ret);
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ret = ERROR;
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}
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leave_cancellation_point();
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return ret;
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}
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/****************************************************************************
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* Name: write
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*
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* Description:
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* write() writes up to nytes bytes to the file referenced by the file
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* descriptor fd from the buffer starting at buf.
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*
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* Input Parameters:
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* fd - file descriptor to write to
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* buf - Data to write
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* nbytes - Length of data to write
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*
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* Returned Value:
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* On success, the number of bytes written are returned (zero indicates
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* nothing was written). On error, -1 is returned, and errno is set appro-
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* priately:
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*
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* EAGAIN
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* Non-blocking I/O has been selected using O_NONBLOCK and the write
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* would block.
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* EBADF
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* fd is not a valid file descriptor or is not open for writing.
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* EFAULT
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* buf is outside your accessible address space.
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* EFBIG
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* An attempt was made to write a file that exceeds the implementation
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* defined maximum file size or the process's file size limit, or
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* to write at a position past the maximum allowed offset.
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* EINTR
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* The call was interrupted by a signal before any data was written.
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* EINVAL
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* fd is attached to an object which is unsuitable for writing; or
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* the file was opened with the O_DIRECT flag, and either the address
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* specified in buf, the value specified in count, or the current
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* file offset is not suitably aligned.
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* EIO
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* A low-level I/O error occurred while modifying the inode.
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* ENOSPC
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* The device containing the file referred to by fd has no room for
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* the data.
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* EPIPE
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* fd is connected to a pipe or socket whose reading end is closed.
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* When this happens the writing process will also receive a SIGPIPE
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* signal. (Thus, the write return value is seen only if the program
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* catches, blocks or ignores this signal.)
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*
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****************************************************************************/
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ssize_t write(int fd, FAR const void *buf, size_t nbytes)
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{
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struct iovec iov;
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iov.iov_base = (void *)buf;
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iov.iov_len = nbytes;
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return writev(fd, &iov, 1);
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}
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