int pipecommon_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup)
{
FAR struct inode *inode = filep->f_inode;
FAR struct pipe_dev_s *dev = inode->i_private;
pollevent_t eventset;
pipe_ndx_t nbytes;
int ret = OK;
int i;
DEBUGASSERT(dev && fds);
/* Are we setting up the poll? Or tearing it down? */
pipecommon_semtake(&dev->d_bfsem);
if (setup)
{
/* This is a request to set up the poll. Find an available
* slot for the poll structure reference
*/
for (i = 0; i < CONFIG_DEV_PIPE_NPOLLWAITERS; i++)
{
/* Find an available slot */
if (!dev->d_fds[i])
{
/* Bind the poll structure and this slot */
dev->d_fds[i] = fds;
fds->priv = &dev->d_fds[i];
break;
}
}
if (i >= CONFIG_DEV_PIPE_NPOLLWAITERS)
{
fds->priv = NULL;
ret = -EBUSY;
goto errout;
}
/* Should immediately notify on any of the requested events?
* First, determine how many bytes are in the buffer
*/
if (dev->d_wrndx >= dev->d_rdndx)
{
nbytes = dev->d_wrndx - dev->d_rdndx;
}
else
{
nbytes = (CONFIG_DEV_PIPE_SIZE-1) + dev->d_wrndx - dev->d_rdndx;
}
/* Notify the POLLOUT event if the pipe is not full, but only if
* there is readers. */
eventset = 0;
if (nbytes < (CONFIG_DEV_PIPE_SIZE-1))
{
eventset |= POLLOUT;
}
/* Notify the POLLIN event if the pipe is not empty */
if (nbytes > 0)
{
eventset |= POLLIN;
}
/* Notify the POLLHUP event if the pipe is empty and no writers */
if (nbytes == 0 && dev->d_nwriters <= 0)
{
eventset |= POLLHUP;
}
/* Change POLLOUT to POLLERR, if no readers and policy 0. */
if ((eventset | POLLOUT) &&
PIPE_IS_POLICY_0(dev->d_flags) &&
dev->d_nreaders <= 0)
{
eventset |= POLLERR;
}
if (eventset)
{
pipecommon_pollnotify(dev, eventset);
}
}
else
{
/* This is a request to tear down the poll. */
struct pollfd **slot = (struct pollfd **)fds->priv;
#ifdef CONFIG_DEBUG
if (!slot)
{
ret = -EIO;
goto errout;
}
#endif
/* Remove all memory of the poll setup */
*slot = NULL;
fds->priv = NULL;
}
errout:
sem_post(&dev->d_bfsem);
return ret;
}
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;
int sval;
DEBUGASSERT(dev);
pipe_dumpbuffer("To PIPE:", (uint8_t*)buffer, len);
if (len == 0)
{
return 0;
}
/* At present, this method cannot be called from interrupt handlers. That is
* because it calls sem_wait (via pipecommon_semtake below) and sem_wait cannot
* be called from interrupt level. This actually happens fairly commonly
* IF dbg() is called from interrupt handlers and stdout is being redirected
* via a pipe. In that case, the debug output will try to go out the pipe
* (interrupt handlers should use the lldbg() APIs).
*
* On the other hand, it would be very valuable to be able to feed the pipe
* from an interrupt handler! TODO: Consider disabling interrupts instead
* of taking semaphores so that pipes can be written from interrupt handlers
*/
DEBUGASSERT(up_interrupt_context() == false);
/* Make sure that we have exclusive access to the device structure */
if (sem_wait(&dev->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->d_wrndx + 1;
if (nxtwrndx >= CONFIG_DEV_PIPE_SIZE)
{
nxtwrndx = 0;
}
/* Would the next write overflow the circular buffer? */
if (nxtwrndx != dev->d_rdndx)
{
/* No... copy the byte */
dev->d_buffer[dev->d_wrndx] = *buffer++;
dev->d_wrndx = nxtwrndx;
/* Is the write complete? */
if (++nwritten >= len)
{
/* Yes.. Notify all of the waiting readers that more data is available */
while (sem_getvalue(&dev->d_rdsem, &sval) == 0 && sval < 0)
{
sem_post(&dev->d_rdsem);
}
/* Notify all poll/select waiters that they can write to the FIFO */
pipecommon_pollnotify(dev, POLLIN);
/* Return the number of bytes written */
sem_post(&dev->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 all of the waiting readers that more data is available */
while (sem_getvalue(&dev->d_rdsem, &sval) == 0 && sval < 0)
{
sem_post(&dev->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->d_bfsem);
return nwritten;
}
/* There is more to be written.. wait for data to be removed from the pipe */
sched_lock();
sem_post(&dev->d_bfsem);
pipecommon_semtake(&dev->d_wrsem);
sched_unlock();
pipecommon_semtake(&dev->d_bfsem);
}
}
}
int pipecommon_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode = filep->f_inode;
FAR struct pipe_dev_s *dev = inode->i_private;
int ret = -EINVAL;
#ifdef CONFIG_DEBUG
/* Some sanity checking */
if (dev == NULL)
{
return -EBADF;
}
#endif
pipecommon_semtake(&dev->d_bfsem);
switch (cmd)
{
case PIPEIOC_POLICY:
{
if (arg != 0)
{
PIPE_POLICY_1(dev->d_flags);
}
else
{
PIPE_POLICY_0(dev->d_flags);
}
ret = OK;
}
break;
case FIONREAD:
{
int count;
/* Determine the number of bytes available in the buffer */
if (dev->d_wrndx < dev->d_rdndx)
{
count = (CONFIG_DEV_PIPE_SIZE - dev->d_rdndx) + dev->d_wrndx;
}
else
{
count = dev->d_wrndx - dev->d_rdndx;
}
*(FAR int *)arg = count;
ret = 0;
}
break;
case FIONWRITE:
{
int count;
/* Determine the number of bytes free in the buffer */
if (dev->d_wrndx < dev->d_rdndx)
{
count = (dev->d_rdndx - dev->d_wrndx) - 1;
}
else
{
count = ((CONFIG_DEV_PIPE_SIZE - dev->d_wrndx) + dev->d_rdndx) - 1;
}
*(FAR int *)arg = count;
ret = 0;
}
break;
default:
break;
}
sem_post(&dev->d_bfsem);
return ret;
}
int pipecommon_close(FAR struct file *filep)
{
struct inode *inode = filep->f_inode;
struct pipe_dev_s *dev = inode->i_private;
int sval;
DEBUGASSERT(dev && dev->d_refs > 0);
/* 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->d_bfsem);
/* Decrement the number of references on the pipe. Check if there are
* still outstanding references to the pipe.
*/
/* Check if the decremented reference count would go to zero */
if (--dev->d_refs > 0)
{
/* No more references.. If opened for writing, decrement the count of
* writers on the pipe instance.
*/
if ((filep->f_oflags & O_WROK) != 0)
{
/* If there are no longer any writers on the pipe, then notify all of the
* waiting readers that they must return end-of-file.
*/
if (--dev->d_nwriters <= 0)
{
while (sem_getvalue(&dev->d_rdsem, &sval) == 0 && sval < 0)
{
sem_post(&dev->d_rdsem);
}
/* Inform poll readers that other end closed. */
pipecommon_pollnotify(dev, POLLHUP);
}
}
/* If opened for reading, decrement the count of readers on the pipe
* instance.
*/
if ((filep->f_oflags & O_RDOK) != 0)
{
if (--dev->d_nreaders <= 0)
{
if (PIPE_IS_POLICY_0(dev->d_flags))
{
/* Inform poll writers that other end closed. */
pipecommon_pollnotify(dev, POLLERR);
}
}
}
}
/* What is the buffer management policy? Do we free the buffe when the
* last client closes the pipe policy 0, or when the buffer becomes empty.
* In the latter case, the buffer data will remain valid and can be
* obtained when the pipe is re-opened.
*/
else if (PIPE_IS_POLICY_0(dev->d_flags) || dev->d_wrndx == dev->d_rdndx)
{
/* Policy 0 or the buffer is empty ... deallocate the buffer now. */
kmm_free(dev->d_buffer);
dev->d_buffer = NULL;
/* And reset all counts and indices */
dev->d_wrndx = 0;
dev->d_rdndx = 0;
dev->d_refs = 0;
dev->d_nwriters = 0;
dev->d_nreaders = 0;
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
/* If, in addition, we have been unlinked, then also need to free the
* device structure as well to prevent a memory leak.
*/
if (PIPE_IS_UNLINKED(dev->d_flags))
{
pipecommon_freedev(dev);
return OK;
}
#endif
}
sem_post(&dev->d_bfsem);
return OK;
}
int pipecommon_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode = filep->f_inode;
FAR struct pipe_dev_s *dev = inode->i_private;
int ret = -EINVAL;
#ifdef CONFIG_DEBUG_FEATURES
/* Some sanity checking */
if (dev == NULL)
{
return -EBADF;
}
#endif
pipecommon_semtake(&dev->d_bfsem);
switch (cmd)
{
case PIPEIOC_POLICY:
{
if (arg != 0)
{
PIPE_POLICY_1(dev->d_flags);
}
else
{
PIPE_POLICY_0(dev->d_flags);
}
ret = OK;
}
break;
case FIONWRITE: /* Number of bytes waiting in send queue */
case FIONREAD: /* Number of bytes available for reading */
{
int count;
/* Determine the number of bytes written to the buffer. This is,
* of course, also the number of bytes that may be read from the
* buffer.
*
* d_rdndx - index to remove next byte from the buffer
* d_wrndx - Index to next location to add a byte to the buffer.
*/
if (dev->d_wrndx < dev->d_rdndx)
{
count = (dev->d_bufsize - dev->d_rdndx) + dev->d_wrndx;
}
else
{
count = dev->d_wrndx - dev->d_rdndx;
}
*(FAR int *)((uintptr_t)arg) = count;
ret = 0;
}
break;
/* Free space in buffer */
case FIONSPACE:
{
int count;
/* Determine the number of bytes free in the buffer.
*
* d_rdndx - index to remove next byte from the buffer
* d_wrndx - Index to next location to add a byte to the buffer.
*/
if (dev->d_wrndx < dev->d_rdndx)
{
count = (dev->d_rdndx - dev->d_wrndx) - 1;
}
else
{
count = ((dev->d_bufsize - dev->d_wrndx) + dev->d_rdndx) - 1;
}
*(FAR int *)((uintptr_t)arg) = count;
ret = 0;
}
break;
default:
break;
}
sem_post(&dev->d_bfsem);
return ret;
}
