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