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- /****************************************************************************
- * fs/vfs/fs_write.c
- *
- * Copyright (C) 2007-2009, 2012-2014, 2016-2017 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 <sys/types.h>
- #include <unistd.h>
- #include <fcntl.h>
- #include <sched.h>
- #include <errno.h>
- #include <assert.h>
- #ifdef CONFIG_NET_TCP
- # include <sys/socket.h>
- #endif
- #include <nuttx/cancelpt.h>
- #include <nuttx/net/net.h>
- #include "inode/inode.h"
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: file_write
- *
- * Description:
- * Equivalent to the standard write() function except that is accepts a
- * struct file instance instead of a file descriptor. It is functionally
- * equivalent to write() except that in addition to the differences in
- * input paramters:
- *
- * - It does not modify the errno variable,
- * - It is not a cancellation point, and
- * - It does not handle socket descriptors.
- *
- * Input Parameters:
- * filep - Instance of struct file to use with the write
- * buf - Data to write
- * nbytes - Length of data to write
- *
- * Returned Value:
- * On success, the number of bytes written are returned (zero indicates
- * nothing was written). On any failure, a negated errno value is returned
- * (see comments withwrite() for a description of the appropriate errno
- * values).
- *
- ****************************************************************************/
- ssize_t file_write(FAR struct file *filep, FAR const void *buf, size_t nbytes)
- {
- FAR struct inode *inode;
- /* Was this file opened for write access? */
- if ((filep->f_oflags & O_WROK) == 0)
- {
- return -EBADF;
- }
- /* Is a driver registered? Does it support the write method? */
- inode = filep->f_inode;
- if (!inode || !inode->u.i_ops || !inode->u.i_ops->write)
- {
- return -EBADF;
- }
- /* Yes, then let the driver perform the write */
- return inode->u.i_ops->write(filep, buf, nbytes);
- }
- /****************************************************************************
- * Name: nx_write
- *
- * Description:
- * nx_write() writes up to nytes bytes to the file referenced by the file
- * descriptor fd from the buffer starting at buf. nx_write() is an
- * internal OS function. It is functionally equivalent to write() except
- * that:
- *
- * - It does not modify the errno variable, and
- * - It is not a cancellation point.
- *
- * Input Parameters:
- * fd - file descriptor (or socket descriptor) to write to
- * buf - Data to write
- * nbytes - Length of data to write
- *
- * Returned Value:
- * On success, the number of bytes written are returned (zero indicates
- * nothing was written). On any failure, a negated errno value is returned
- * (see comments withwrite() for a description of the appropriate errno
- * values).
- *
- ****************************************************************************/
- ssize_t nx_write(int fd, FAR const void *buf, size_t nbytes)
- {
- FAR struct file *filep;
- ssize_t ret;
- if (buf == NULL)
- {
- return -EINVAL;
- }
- /* Did we get a valid file descriptor? */
- if ((unsigned int)fd >= CONFIG_NFILE_DESCRIPTORS)
- {
- #ifdef CONFIG_NET_TCP
- /* Write to a socket descriptor is equivalent to send with flags == 0. */
- ret = nx_send(fd, buf, nbytes, 0);
- #else
- ret = -EBADF;
- #endif
- }
- else
- {
- /* The descriptor is in the right range to be a file descriptor..
- * write to the file. Note that fs_getfilep() will set the errno on
- * failure.
- */
- ret = (ssize_t)fs_getfilep(fd, &filep);
- if (ret >= 0)
- {
- /* Perform the write operation using the file descriptor as an
- * index. Note that file_write() will set the errno on failure.
- */
- ret = file_write(filep, buf, nbytes);
- }
- }
- return ret;
- }
- /****************************************************************************
- * Name: write
- *
- * Description:
- * write() writes up to nytes bytes to the file referenced by the file
- * descriptor fd from the buffer starting at buf.
- *
- * Input Parameters:
- * fd - file descriptor (or socket descriptor) to write to
- * buf - Data to write
- * nbytes - Length of data to write
- *
- * Returned Value:
- * On success, the number of bytes written are returned (zero indicates
- * nothing was written). On error, -1 is returned, and errno is set appro-
- * priately:
- *
- * EAGAIN
- * Non-blocking I/O has been selected using O_NONBLOCK and the write
- * would block.
- * EBADF
- * fd is not a valid file descriptor or is not open for writing.
- * EFAULT
- * buf is outside your accessible address space.
- * EFBIG
- * An attempt was made to write a file that exceeds the implementation
- * defined maximum file size or the process' file size limit, or
- * to write at a position past the maximum allowed offset.
- * EINTR
- * The call was interrupted by a signal before any data was written.
- * EINVAL
- * fd is attached to an object which is unsuitable for writing; or
- * the file was opened with the O_DIRECT flag, and either the address
- * specified in buf, the value specified in count, or the current
- * file offset is not suitably aligned.
- * EIO
- * A low-level I/O error occurred while modifying the inode.
- * ENOSPC
- * The device containing the file referred to by fd has no room for
- * the data.
- * EPIPE
- * fd is connected to a pipe or socket whose reading end is closed.
- * When this happens the writing process will also receive a SIGPIPE
- * signal. (Thus, the write return value is seen only if the program
- * catches, blocks or ignores this signal.)
- *
- ****************************************************************************/
- ssize_t write(int fd, FAR const void *buf, size_t nbytes)
- {
- ssize_t ret;
- /* write() is a cancellation point */
- (void)enter_cancellation_point();
- /* Let nx_write() do all of the work */
- ret = nx_write(fd, buf, nbytes);
- if (ret < 0)
- {
- set_errno(-ret);
- ret = ERROR;
- }
- leave_cancellation_point();
- return ret;
- }
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