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Diffstat (limited to 'nuttx/drivers/pipes/fifo.c')
-rw-r--r-- | nuttx/drivers/pipes/fifo.c | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/nuttx/drivers/pipes/fifo.c b/nuttx/drivers/pipes/fifo.c new file mode 100644 index 000000000..03aafd0f0 --- /dev/null +++ b/nuttx/drivers/pipes/fifo.c @@ -0,0 +1,139 @@ +/**************************************************************************** + * drivers/pipes/fifo.c + * + * Copyright (C) 2008-2009 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 <stdint.h> +#include <nuttx/fs/fs.h> +#include <errno.h> + +#include "pipe_common.h" + +#if CONFIG_DEV_PIPE_SIZE > 0 + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +/**************************************************************************** + * Private Types + ****************************************************************************/ + +/**************************************************************************** + * Private Function Prototypes + ****************************************************************************/ + +/**************************************************************************** + * Private Data + ****************************************************************************/ + +static const struct file_operations fifo_fops = +{ + pipecommon_open, /* open */ + pipecommon_close, /* close */ + pipecommon_read, /* read */ + pipecommon_write, /* write */ + 0, /* seek */ + 0 /* ioctl */ +#ifndef CONFIG_DISABLE_POLL + , pipecommon_poll /* poll */ +#endif +}; + +/**************************************************************************** + * 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 */ |