/****************************************************************************
* drivers/fifo.c
*
* Copyright (C) 2008 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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.
*
****************************************************************************/
/****************************************************************************
* Compilation Switches
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <nuttx/fs.h>
#include <errno.h>
#include "pipe_common.h"
#if CONFIG_DEV_PIPE_SIZE > 0
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
static struct file_operations fifo_fops =
{
pipecommon_open, /* open */
pipecommon_close, /* close */
pipecommon_read, /* read */
pipecommon_write, /* write */
0, /* seek */
0, /* ioctl */
0 /* poll */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: mkfifo
*
* Description:
* mkfifo() makes a FIFO device driver file with name 'pathname.' Unlike
* Linux, a NuttX FIFO is not a special file type but simply a device driver
* instance. 'mode' specifies the FIFO's permissions.
*
* Once the FIFO has been created by mkfifo(), any thread can open it for
* reading or writing, in the same way as an ordinary file. However, it must
* have been opened from both reading and writing before input or output
* can be performed. This FIFO implementation will block all attempts to
* open a FIFO read-only until at least one thread has opened the FIFO for
* writing.
*
* If all threads that write to the FIFO have closed, subsequent calls to
* read() on the FIFO will return 0 (end-of-file).
*
* Inputs:
* pathname - The full path to the FIFO instance to attach to or to create
* (if not already created).
* mode - Ignored for now
*
* Return:
* 0 is returned on success; otherwise, -1 is returned with errno set
* appropriately.
*
****************************************************************************/
int mkfifo(FAR const char *pathname, mode_t mode)
{
struct pipe_dev_s *dev;
int ret;
/* Allocate and initialize a new device structure instance */
dev = pipecommon_allocdev();
if (!dev)
{
return -ENOMEM;
}
ret = register_driver(pathname, &fifo_fops, mode, (void*)dev);
if (ret != 0)
{
pipecommon_freedev(dev);
}
return ret;
}
#endif /* CONFIG_DEV_PIPE_SIZE > 0 */
