422 lines
12 KiB
C
422 lines
12 KiB
C
|
/****************************************************************************
|
||
|
|
* drivers/pipe-common.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 <sys/stat.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <string.h>
|
||
|
|
#include <sched.h>
|
||
|
|
#include <semaphore.h>
|
||
|
|
#include <fcntl.h>
|
||
|
|
#include <errno.h>
|
||
|
|
#include <assert.h>
|
||
|
|
#include <nuttx/fs.h>
|
||
|
|
|
||
|
|
#include "pipe-common.h"
|
||
|
|
|
||
|
|
#if CONFIG_DEV_FIFO_SIZE > 0
|
||
|
|
|
||
|
|
/****************************************************************************
|
||
|
|
* Definitions
|
||
|
|
****************************************************************************/
|
||
|
|
|
||
|
|
/****************************************************************************
|
||
|
|
* Private Types
|
||
|
|
****************************************************************************/
|
||
|
|
|
||
|
|
/****************************************************************************
|
||
|
|
* Private Function Prototypes
|
||
|
|
****************************************************************************/
|
||
|
|
|
||
|
|
static void pipecommon_semtake(sem_t *sem);
|
||
|
|
|
||
|
|
/****************************************************************************
|
||
|
|
* Private Data
|
||
|
|
****************************************************************************/
|
||
|
|
|
||
|
|
/****************************************************************************
|
||
|
|
* Private Functions
|
||
|
|
****************************************************************************/
|
||
|
|
|
||
|
|
/****************************************************************************
|
||
|
|
* Name: pipecommon_semtake
|
||
|
|
****************************************************************************/
|
||
|
|
static void pipecommon_semtake(sem_t *sem)
|
||
|
|
{
|
||
|
|
while (sem_wait(sem) != 0)
|
||
|
|
{
|
||
|
|
/* The only case that an error should occur here is if the wait was
|
||
|
|
* awakened by a signal.
|
||
|
|
*/
|
||
|
|
|
||
|
|
ASSERT(errno == EINTR);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/****************************************************************************
|
||
|
|
* Public Functions
|
||
|
|
****************************************************************************/
|
||
|
|
|
||
|
|
/****************************************************************************
|
||
|
|
* Name: pipecommon_allocdev
|
||
|
|
****************************************************************************/
|
||
|
|
FAR struct pipe_dev_s *pipecommon_allocdev(void)
|
||
|
|
{
|
||
|
|
struct pipe_dev_s *dev;
|
||
|
|
|
||
|
|
/* Allocate a private structure to manage the FIFO */
|
||
|
|
|
||
|
|
dev = (struct pipe_dev_s *)malloc(sizeof(struct pipe_dev_s));
|
||
|
|
if (dev)
|
||
|
|
{
|
||
|
|
/* Initialize the private structure */
|
||
|
|
|
||
|
|
memset(&dev->s, 0, sizeof(struct pipe_state_s));
|
||
|
|
sem_init(&dev->s.d_bfsem, 0, 1);
|
||
|
|
sem_init(&dev->s.d_rdsem, 0, 0);
|
||
|
|
sem_init(&dev->s.d_wrsem, 0, 0);
|
||
|
|
}
|
||
|
|
return dev;
|
||
|
|
}
|
||
|
|
|
||
|
|
/****************************************************************************
|
||
|
|
* Name: pipecommon_freedev
|
||
|
|
****************************************************************************/
|
||
|
|
void pipecommon_freedev(FAR struct pipe_dev_s *dev)
|
||
|
|
{
|
||
|
|
sem_destroy(&dev->s.d_bfsem);
|
||
|
|
sem_destroy(&dev->s.d_rdsem);
|
||
|
|
sem_destroy(&dev->s.d_wrsem);
|
||
|
|
free(dev);
|
||
|
|
}
|
||
|
|
|
||
|
|
/****************************************************************************
|
||
|
|
* Name: pipecommon_open
|
||
|
|
****************************************************************************/
|
||
|
|
int pipecommon_open(FAR struct file *filep)
|
||
|
|
{
|
||
|
|
struct inode *inode = filep->f_inode;
|
||
|
|
struct pipe_dev_s *dev = inode->i_private;
|
||
|
|
|
||
|
|
/* Some sanity checking */
|
||
|
|
#if CONFIG_DEBUG
|
||
|
|
if (!dev)
|
||
|
|
{
|
||
|
|
return -EBADF;
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
/* Make sure that we have exclusive access to the device structure */
|
||
|
|
|
||
|
|
if (sem_wait(&dev->s.d_bfsem) == 0)
|
||
|
|
{
|
||
|
|
/* Increment the reference count on the pipe instance */
|
||
|
|
|
||
|
|
dev->s.d_refs++;
|
||
|
|
|
||
|
|
/* If opened for writing, increment the count of writers on on the pipe instance */
|
||
|
|
|
||
|
|
if ((filep->f_oflags & O_WROK) != 0)
|
||
|
|
{
|
||
|
|
dev->s.d_nwriters++;
|
||
|
|
}
|
||
|
|
|
||
|
|
(void)sem_post(&dev->s.d_bfsem);
|
||
|
|
return OK;
|
||
|
|
}
|
||
|
|
return ERROR;
|
||
|
|
}
|
||
|
|
|
||
|
|
/****************************************************************************
|
||
|
|
* Name: pipecommon_close
|
||
|
|
****************************************************************************/
|
||
|
|
int pipecommon_close(FAR struct file *filep)
|
||
|
|
{
|
||
|
|
struct inode *inode = filep->f_inode;
|
||
|
|
struct pipe_dev_s *dev = inode->i_private;
|
||
|
|
|
||
|
|
/* Some sanity checking */
|
||
|
|
#if CONFIG_DEBUG
|
||
|
|
if (!dev)
|
||
|
|
{
|
||
|
|
return -EBADF;
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/* Make sure that we have exclusive access to the device structure.
|
||
|
|
* NOTE: close() is supposed to return EINTR if interrupted, however
|
||
|
|
* I've never seen anyone check that.
|
||
|
|
*/
|
||
|
|
|
||
|
|
pipecommon_semtake(&dev->s.d_bfsem);
|
||
|
|
|
||
|
|
/* Check if the decremented reference count would be zero */
|
||
|
|
|
||
|
|
if (dev->s.d_refs > 1)
|
||
|
|
{
|
||
|
|
/* No.. then just decrement the reference count */
|
||
|
|
|
||
|
|
dev->s.d_refs--;
|
||
|
|
|
||
|
|
/* If opened for writing, decrement the count of writers on on the pipe instance */
|
||
|
|
|
||
|
|
if ((filep->f_oflags & O_WROK) != 0)
|
||
|
|
{
|
||
|
|
/* If there are no longer any writers on the pipe, then notify any
|
||
|
|
* waiting readers that must return end-of-file.
|
||
|
|
*/
|
||
|
|
|
||
|
|
if (--dev->s.d_nwriters <= 0 && dev->s.d_rdwaiters > 0)
|
||
|
|
{
|
||
|
|
dev->s.d_rdwaiters--;
|
||
|
|
sem_post(&dev->s.d_rdsem);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
sem_post(&dev->s.d_bfsem);
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
/* Then nothing else can be holding the semaphore, so it is save to */
|
||
|
|
|
||
|
|
inode->i_private = NULL;
|
||
|
|
sem_post(&dev->s.d_bfsem);
|
||
|
|
|
||
|
|
/* Then free the fifo structure instance */
|
||
|
|
|
||
|
|
pipecommon_freedev(dev);
|
||
|
|
}
|
||
|
|
return OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
/****************************************************************************
|
||
|
|
* Name: pipecommon_read
|
||
|
|
****************************************************************************/
|
||
|
|
ssize_t pipecommon_read(FAR struct file *filep, FAR char *buffer, size_t len)
|
||
|
|
{
|
||
|
|
struct inode *inode = filep->f_inode;
|
||
|
|
struct pipe_dev_s *dev = inode->i_private;
|
||
|
|
ssize_t nread = 0;
|
||
|
|
int ret;
|
||
|
|
|
||
|
|
/* Some sanity checking */
|
||
|
|
#if CONFIG_DEBUG
|
||
|
|
if (!dev)
|
||
|
|
{
|
||
|
|
return -ENODEV;
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/* Make sure that we have exclusive access to the device structure */
|
||
|
|
|
||
|
|
if (sem_wait(&dev->s.d_bfsem) < 0)
|
||
|
|
{
|
||
|
|
return ERROR;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* If the fifo is empty, then wait for something to be written to it */
|
||
|
|
|
||
|
|
while (dev->s.d_wrndx == dev->s.d_rdndx)
|
||
|
|
{
|
||
|
|
/* If O_NONBLOCK was set, then return EGAIN */
|
||
|
|
|
||
|
|
if (filep->f_oflags & O_NONBLOCK)
|
||
|
|
{
|
||
|
|
sem_post(&dev->s.d_bfsem);
|
||
|
|
return -EAGAIN;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* If there are no writers on the pipe, then return end of file */
|
||
|
|
|
||
|
|
if (dev->s.d_nwriters <= 0)
|
||
|
|
{
|
||
|
|
sem_post(&dev->s.d_bfsem);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Otherwise, wait for something to be written to the FIFO */
|
||
|
|
|
||
|
|
dev->s.d_rdwaiters++;
|
||
|
|
sched_lock();
|
||
|
|
sem_post(&dev->s.d_bfsem);
|
||
|
|
ret = sem_wait(&dev->s.d_rdsem);
|
||
|
|
sched_unlock();
|
||
|
|
if (ret < 0 || sem_wait(&dev->s.d_bfsem) < 0)
|
||
|
|
{
|
||
|
|
return ERROR;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Then return whatever is available in the FIFO (which is at least one byte) */
|
||
|
|
|
||
|
|
nread = 0;
|
||
|
|
while (nread < len && dev->s.d_wrndx != dev->s.d_rdndx)
|
||
|
|
{
|
||
|
|
*buffer++ = dev->d_buffer[dev->s.d_rdndx];
|
||
|
|
if (++dev->s.d_rdndx >= CONFIG_DEV_FIFO_SIZE)
|
||
|
|
{
|
||
|
|
dev->s.d_rdndx = 0;
|
||
|
|
}
|
||
|
|
nread++;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Notify any waiting writers that bytes have been removed from the buffer */
|
||
|
|
|
||
|
|
if (dev->s.d_nwrwaiters > 0)
|
||
|
|
{
|
||
|
|
dev->s.d_nwrwaiters--;
|
||
|
|
sem_post(&dev->s.d_wrsem);
|
||
|
|
}
|
||
|
|
|
||
|
|
sem_post(&dev->s.d_bfsem);
|
||
|
|
return nread;
|
||
|
|
}
|
||
|
|
|
||
|
|
/****************************************************************************
|
||
|
|
* Name: pipecommon_write
|
||
|
|
****************************************************************************/
|
||
|
|
ssize_t pipecommon_write(FAR struct file *filep, FAR const char *buffer, size_t len)
|
||
|
|
{
|
||
|
|
struct inode *inode = filep->f_inode;
|
||
|
|
struct pipe_dev_s *dev = inode->i_private;
|
||
|
|
ssize_t nwritten = 0;
|
||
|
|
ssize_t last;
|
||
|
|
int nxtwrndx;
|
||
|
|
|
||
|
|
/* Some sanity checking */
|
||
|
|
#if CONFIG_DEBUG
|
||
|
|
if (!dev)
|
||
|
|
{
|
||
|
|
return -ENODEV;
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/* Make sure that we have exclusive access to the device structure */
|
||
|
|
|
||
|
|
if (sem_wait(&dev->s.d_bfsem) < 0)
|
||
|
|
{
|
||
|
|
return ERROR;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Loop until all of the bytes have been written */
|
||
|
|
|
||
|
|
last = 0;
|
||
|
|
for (;;)
|
||
|
|
{
|
||
|
|
/* Calculate the write index AFTER the next byte is written */
|
||
|
|
|
||
|
|
nxtwrndx = dev->s.d_wrndx + 1;
|
||
|
|
if (nxtwrndx >= CONFIG_DEV_FIFO_SIZE)
|
||
|
|
{
|
||
|
|
nxtwrndx = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Would the next write overflow the circular buffer? */
|
||
|
|
|
||
|
|
if (nxtwrndx != dev->s.d_rdndx)
|
||
|
|
{
|
||
|
|
/* No... copy the byte */
|
||
|
|
|
||
|
|
dev->d_buffer[dev->s.d_wrndx] = *buffer++;
|
||
|
|
dev->s.d_wrndx = nxtwrndx;
|
||
|
|
|
||
|
|
/* Is the write complete? */
|
||
|
|
|
||
|
|
if (++nwritten >= len)
|
||
|
|
{
|
||
|
|
/* Yes.. Notify the waiting readers that more data is available */
|
||
|
|
|
||
|
|
if (dev->s.d_rdwaiters > 0)
|
||
|
|
{
|
||
|
|
dev->s.d_rdwaiters--;
|
||
|
|
sem_post(&dev->s.d_rdsem);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Return the number of bytes written */
|
||
|
|
|
||
|
|
sem_post(&dev->s.d_bfsem);
|
||
|
|
return len;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
/* There is not enough room for the next byte. Was anything written in this pass? */
|
||
|
|
|
||
|
|
if (last < nwritten)
|
||
|
|
{
|
||
|
|
/* Yes.. Notify the waiting readers that more data is available */
|
||
|
|
|
||
|
|
if (dev->s.d_rdwaiters > 0)
|
||
|
|
{
|
||
|
|
dev->s.d_rdwaiters--;
|
||
|
|
sem_post(&dev->s.d_rdsem);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
last = nwritten;
|
||
|
|
|
||
|
|
/* If O_NONBLOCK was set, then return partial bytes written or EGAIN */
|
||
|
|
|
||
|
|
if (filep->f_oflags & O_NONBLOCK)
|
||
|
|
{
|
||
|
|
if (nwritten == 0)
|
||
|
|
{
|
||
|
|
nwritten = -EAGAIN;
|
||
|
|
}
|
||
|
|
sem_post(&dev->s.d_bfsem);
|
||
|
|
return nwritten;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* There is more to be written.. wait for data to be removed from the FIFO */
|
||
|
|
|
||
|
|
dev->s.d_nwrwaiters++;
|
||
|
|
sched_lock();
|
||
|
|
sem_post(&dev->s.d_bfsem);
|
||
|
|
pipecommon_semtake(&dev->s.d_wrsem);
|
||
|
|
sched_unlock();
|
||
|
|
pipecommon_semtake(&dev->s.d_bfsem);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* CONFIG_DEV_FIFO_SIZE > 0 */
|