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/****************************************************************************
* fs/vfs/fs_write.c
*
* Copyright (C) 2007-2009, 2012-2014 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>
#if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0
# include <sys/socket.h>
#endif
#include "inode/inode.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* 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. Currently used
* only by aio_write();
*
****************************************************************************/
ssize_t file_write(FAR struct file *filep, FAR const void *buf, size_t nbytes)
{
FAR struct inode *inode;
int ret;
int err;
/* Was this file opened for write access? */
if ((filep->f_oflags & O_WROK) == 0)
{
err = EBADF;
goto errout;
}
/* 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)
{
err = EBADF;
goto errout;
}
/* Yes, then let the driver perform the write */
ret = inode->u.i_ops->write(filep, buf, nbytes);
if (ret < 0)
{
err = -ret;
goto errout;
}
return ret;
errout:
set_errno(err);
return ERROR;
}
/***************************************************************************
* Name: write
*
* Description:
* write() writes up to nytes bytes to the file referenced by the file
* descriptor fd from the buffer starting at buf.
*
* 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.)
*
* Assumptions:
*
********************************************************************************************/
ssize_t write(int fd, FAR const void *buf, size_t nbytes)
{
#if CONFIG_NFILE_DESCRIPTORS > 0
FAR struct file *filep;
#endif
/* Did we get a valid file descriptor? */
#if CONFIG_NFILE_DESCRIPTORS > 0
if ((unsigned int)fd >= CONFIG_NFILE_DESCRIPTORS)
#endif
{
/* Write to a socket descriptor is equivalent to send with flags == 0 */
#if defined(CONFIG_NET_TCP) && CONFIG_NSOCKET_DESCRIPTORS > 0
return send(fd, buf, nbytes, 0);
#else
set_errno(EBADF);
return ERROR;
#endif
}
#if CONFIG_NFILE_DESCRIPTORS > 0
/* The descriptor is in the right range to be a file descriptor... write
* to the file.
*/
filep = fs_getfilep(fd);
if (!filep)
{
/* The errno value has already been set */
return ERROR;
}
/* Perform the write operation using the file descriptor as an index */
return file_write(filep, buf, nbytes);
#endif
}
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