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git-svn-id: http://svn.code.sf.net/p/nuttx/code/trunk@5153 42af7a65-404d-4744-a932-0658087f49c3
This commit is contained in:
patacongo
2012-09-17 18:18:44 +00:00
commit 57623d42eb
5691 changed files with 1361853 additions and 0 deletions
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nuttx/drivers/pipes/Kconfig
+4
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#
# For a description of the syntax of this configuration file,
# see misc/tools/kconfig-language.txt.
#
nuttx/drivers/pipes/Make.defs
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############################################################################
# drivers/pipes/Make.defs
#
# Copyright (C) 2009, 2011 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.
#
############################################################################
ifneq ($(CONFIG_NFILE_DESCRIPTORS),0)
# Include pipe driver
CSRCS += pipe.c fifo.c pipe_common.c
# Include pipe build support
DEPPATH += --dep-path pipes
VPATH += :pipes
endif
nuttx/drivers/pipes/fifo.c
+139
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/****************************************************************************
* 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 */
nuttx/drivers/pipes/pipe.c
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/****************************************************************************
* drivers/pipes/pipe.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.
*
****************************************************************************/
/****************************************************************************
* Compilation Switches
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <nuttx/fs/fs.h>
#include <stdio.h>
#include <unistd.h>
#include <semaphore.h>
#include <fcntl.h>
#include <errno.h>
#include "pipe_common.h"
#if CONFIG_DEV_PIPE_SIZE > 0
/****************************************************************************
* Definitions
****************************************************************************/
#define MAX_PIPES 32
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int pipe_close(FAR struct file *filep);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations pipe_fops =
{
pipecommon_open, /* open */
pipe_close, /* close */
pipecommon_read, /* read */
pipecommon_write, /* write */
0, /* seek */
0 /* ioctl */
#ifndef CONFIG_DISABLE_POLL
, pipecommon_poll /* poll */
#endif
};
static sem_t g_pipesem = { 1 };
static uint32_t g_pipeset = 0;
static uint32_t g_pipecreated = 0;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: pipe_allocate
****************************************************************************/
static inline int pipe_allocate(void)
{
int pipeno;
int ret = -ENFILE;
for (pipeno = 0; pipeno < MAX_PIPES; pipeno++)
{
if ((g_pipeset & (1 << pipeno)) == 0)
{
g_pipeset |= (1 << pipeno);
ret = pipeno;
break;
}
}
return ret;
}
/****************************************************************************
* Name: pipe_free
****************************************************************************/
static inline void pipe_free(int pipeno)
{
int ret = sem_wait(&g_pipesem);
if (ret == 0)
{
g_pipeset &= ~(1 << pipeno);
(void)sem_post(&g_pipesem);
}
}
/****************************************************************************
* Name: pipe_close
****************************************************************************/
static int pipe_close(FAR struct file *filep)
{
struct inode *inode = filep->f_inode;
struct pipe_dev_s *dev = inode->i_private;
int ret;
/* Some sanity checking */
#if CONFIG_DEBUG
if (!dev)
{
return -EBADF;
}
#endif
/* Perform common close operations */
ret = pipecommon_close(filep);
if (ret == 0 && dev->d_refs == 0)
{
/* Release the pipe when there are no further open references to it. */
pipe_free(dev->d_pipeno);
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: pipe
*
* Description:
* pipe() creates a pair of file descriptors, pointing to a pipe inode, and
* places them in the array pointed to by 'filedes'. filedes[0] is for reading,
* filedes[1] is for writing.
*
* Inputs:
* filedes[2] - The user provided array in which to catch the pipe file
* descriptors
*
* Return:
* 0 is returned on success; otherwise, -1 is returned with errno set
* appropriately.
*
****************************************************************************/
int pipe(int filedes[2])
{
struct pipe_dev_s *dev = NULL;
char devname[16];
int pipeno;
int err;
int ret;
/* Get exclusive access to the pipe allocation data */
ret = sem_wait(&g_pipesem);
if (ret < 0)
{
/* sem_wait() will have already set errno */
return ERROR;
}
/* Allocate a minor number for the pipe device */
pipeno = pipe_allocate();
if (pipeno < 0)
{
(void)sem_post(&g_pipesem);
err = -pipeno;
goto errout;
}
/* Create a pathname to the pipe device */
sprintf(devname, "/dev/pipe%d", pipeno);
/* Check if the pipe device has already been created */
if ((g_pipecreated & (1 << pipeno)) == 0)
{
/* No.. Allocate and initialize a new device structure instance */
dev = pipecommon_allocdev();
if (!dev)
{
(void)sem_post(&g_pipesem);
err = ENOMEM;
goto errout_with_pipe;
}
dev->d_pipeno = pipeno;
/* Register the pipe device */
ret = register_driver(devname, &pipe_fops, 0666, (void*)dev);
if (ret != 0)
{
(void)sem_post(&g_pipesem);
err = -ret;
goto errout_with_dev;
}
/* Remember that we created this device */
g_pipecreated |= (1 << pipeno);
}
(void)sem_post(&g_pipesem);
/* Get a write file descriptor */
filedes[1] = open(devname, O_WRONLY);
if (filedes[1] < 0)
{
err = -filedes[1];
goto errout_with_driver;
}
/* Get a read file descriptor */
filedes[0] = open(devname, O_RDONLY);
if (filedes[0] < 0)
{
err = -filedes[0];
goto errout_with_wrfd;
}
return OK;
errout_with_wrfd:
close(filedes[1]);
errout_with_driver:
unregister_driver(devname);
errout_with_dev:
pipecommon_freedev(dev);
errout_with_pipe:
pipe_free(pipeno);
errout:
errno = err;
return ERROR;
}
#endif /* CONFIG_DEV_PIPE_SIZE > 0 */
nuttx/drivers/pipes/pipe_common.c
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/****************************************************************************
* drivers/pipes/pipe_common.c
*
* Copyright (C) 2008-2009, 2011 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 <sys/stat.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <sched.h>
#include <semaphore.h>
#include <fcntl.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#if CONFIG_DEBUG
# include <nuttx/arch.h>
#endif
#include "pipe_common.h"
#if CONFIG_DEV_PIPE_SIZE > 0
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* CONFIG_DEV_PIPEDUMP will dump the contents of each transfer into and out
* of the pipe.
*/
#ifdef CONFIG_DEV_PIPEDUMP
# define pipe_dumpbuffer(m,a,n) lib_dumpbuffer(m,a,n)
#else
# define pipe_dumpbuffer(m,a,n)
#endif
/****************************************************************************
* 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);
}
}
/****************************************************************************
* Name: pipecommon_pollnotify
****************************************************************************/
#ifndef CONFIG_DISABLE_POLL
static void pipecommon_pollnotify(FAR struct pipe_dev_s *dev, pollevent_t eventset)
{
int i;
for (i = 0; i < CONFIG_DEV_PIPE_NPOLLWAITERS; i++)
{
struct pollfd *fds = dev->d_fds[i];
if (fds)
{
fds->revents |= (fds->events & eventset);
if (fds->revents != 0)
{
fvdbg("Report events: %02x\n", fds->revents);
sem_post(fds->sem);
}
}
}
}
#else
# define pipecommon_pollnotify(dev,event)
#endif
/****************************************************************************
* 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 pipe */
dev = (struct pipe_dev_s *)kmalloc(sizeof(struct pipe_dev_s));
if (dev)
{
/* Initialize the private structure */
memset(dev, 0, sizeof(struct pipe_dev_s));
sem_init(&dev->d_bfsem, 0, 1);
sem_init(&dev->d_rdsem, 0, 0);
sem_init(&dev->d_wrsem, 0, 0);
}
return dev;
}
/****************************************************************************
* Name: pipecommon_freedev
****************************************************************************/
void pipecommon_freedev(FAR struct pipe_dev_s *dev)
{
sem_destroy(&dev->d_bfsem);
sem_destroy(&dev->d_rdsem);
sem_destroy(&dev->d_wrsem);
kfree(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;
int sval;
int ret;
/* Some sanity checking */
#if CONFIG_DEBUG
if (!dev)
{
return -EBADF;
}
#endif
/* Make sure that we have exclusive access to the device structure. The
* sem_wait() call should fail only if we are awakened by a signal.
*/
ret = sem_wait(&dev->d_bfsem);
if (ret != OK)
{
fdbg("sem_wait failed: %d\n", errno);
DEBUGASSERT(errno > 0);
return -errno;
}
/* If this the first reference on the device, then allocate the buffer */
if (dev->d_refs == 0)
{
dev->d_buffer = (uint8_t*)kmalloc(CONFIG_DEV_PIPE_SIZE);
if (!dev->d_buffer)
{
(void)sem_post(&dev->d_bfsem);
return -ENOMEM;
}
}
/* Increment the reference count on the pipe instance */
dev->d_refs++;
/* If opened for writing, increment the count of writers on on the pipe instance */
if ((filep->f_oflags & O_WROK) != 0)
{
dev->d_nwriters++;
/* If this this is the first writer, then the read semaphore indicates the
* number of readers waiting for the first writer. Wake them all up.
*/
if (dev->d_nwriters == 1)
{
while (sem_getvalue(&dev->d_rdsem, &sval) == 0 && sval < 0)
{
sem_post(&dev->d_rdsem);
}
}
}
/* If opened for read-only, then wait for at least one writer on the pipe */
sched_lock();
(void)sem_post(&dev->d_bfsem);
if ((filep->f_oflags & O_RDWR) == O_RDONLY && dev->d_nwriters < 1)
{
/* NOTE: d_rdsem is normally used when the read logic waits for more
* data to be written. But until the first writer has opened the
* pipe, the meaning is different: it is used prevent O_RDONLY open
* calls from returning until there is at least one writer on the pipe.
* This is required both by spec and also because it prevents
* subsequent read() calls from returning end-of-file because there is
* no writer on the pipe.
*/
ret = sem_wait(&dev->d_rdsem);
if (ret != OK)
{
/* The sem_wait() call should fail only if we are awakened by
* a signal.
*/
fdbg("sem_wait failed: %d\n", errno);
DEBUGASSERT(errno > 0);
ret = -errno;
/* Immediately close the pipe that we just opened */
(void)pipecommon_close(filep);
}
}
sched_unlock();
return ret;
}
/****************************************************************************
* Name: pipecommon_close
****************************************************************************/
int pipecommon_close(FAR struct file *filep)
{
struct inode *inode = filep->f_inode;
struct pipe_dev_s *dev = inode->i_private;
int sval;
/* 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->d_bfsem);
/* Check if the decremented reference count would go to zero */
if (dev->d_refs > 1)
{
/* No.. then just decrement the reference count */
dev->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 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);
}
}
}
}
else
{
/* Yes... deallocate the buffer */
kfree(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;
}
sem_post(&dev->d_bfsem);
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;
#ifdef CONFIG_DEV_PIPEDUMP
FAR uint8_t *start = (uint8_t*)buffer;
#endif
ssize_t nread = 0;
int sval;
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->d_bfsem) < 0)
{
return ERROR;
}
/* If the pipe is empty, then wait for something to be written to it */
while (dev->d_wrndx == dev->d_rdndx)
{
/* If O_NONBLOCK was set, then return EGAIN */
if (filep->f_oflags & O_NONBLOCK)
{
sem_post(&dev->d_bfsem);
return -EAGAIN;
}
/* If there are no writers on the pipe, then return end of file */
if (dev->d_nwriters <= 0)
{
sem_post(&dev->d_bfsem);
return 0;
}
/* Otherwise, wait for something to be written to the pipe */
sched_lock();
sem_post(&dev->d_bfsem);
ret = sem_wait(&dev->d_rdsem);
sched_unlock();
if (ret < 0 || sem_wait(&dev->d_bfsem) < 0)
{
return ERROR;
}
}
/* Then return whatever is available in the pipe (which is at least one byte) */
nread = 0;
while (nread < len && dev->d_wrndx != dev->d_rdndx)
{
*buffer++ = dev->d_buffer[dev->d_rdndx];
if (++dev->d_rdndx >= CONFIG_DEV_PIPE_SIZE)
{
dev->d_rdndx = 0;
}
nread++;
}
/* Notify all waiting writers that bytes have been removed from the buffer */
while (sem_getvalue(&dev->d_wrsem, &sval) == 0 && sval < 0)
{
sem_post(&dev->d_wrsem);
}
/* Notify all poll/select waiters that they can write to the FIFO */
pipecommon_pollnotify(dev, POLLOUT);
sem_post(&dev->d_bfsem);
pipe_dumpbuffer("From PIPE:", start, nread);
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;
int sval;
/* Some sanity checking */
#if CONFIG_DEBUG
if (!dev)
{
return -ENODEV;
}
#endif
pipe_dumpbuffer("To PIPE:", (uint8_t*)buffer, len);
/* 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 interupt 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);
}
}
}
/****************************************************************************
* Name: pipecommon_poll
****************************************************************************/
#ifndef CONFIG_DISABLE_POLL
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;
/* Some sanity checking */
#if CONFIG_DEBUG
if (!dev || !fds)
{
return -ENODEV;
}
#endif
/* 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 */
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;
}
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;
}
#endif
#endif /* CONFIG_DEV_PIPE_SIZE > 0 */
nuttx/drivers/pipes/pipe_common.h
+139
View File
@@ -0,0 +1,139 @@
/****************************************************************************
* drivers/pipe/pipe_common.h
*
* 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.
*
****************************************************************************/
#ifndef __DRIVERS_PIPES_PIPE_COMMON_H
#define __DRIVERS_PIPES_PIPE_COMMON_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <poll.h>
#ifndef CONFIG_DEV_PIPE_SIZE
# define CONFIG_DEV_PIPE_SIZE 1024
#endif
#if CONFIG_DEV_PIPE_SIZE > 0
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Maximum number of threads than can be waiting for POLL events */
#ifndef CONFIG_DEV_PIPE_NPOLLWAITERS
# define CONFIG_DEV_PIPE_NPOLLWAITERS 2
#endif
/* Maximum number of open's supported on pipe */
#define CONFIG_DEV_PIPE_MAXUSER 255
/****************************************************************************
* Public Types
****************************************************************************/
/* Make the buffer index as small as possible for the configured pipe size */
#if CONFIG_DEV_PIPE_SIZE > 65535
typedef uint32_t pipe_ndx_t; /* 32-bit index */
#elif CONFIG_DEV_PIPE_SIZE > 255
typedef uint16_t pipe_ndx_t; /* 16-bit index */
#else
typedef uint8_t pipe_ndx_t; /* 8-bit index */
#endif
/* This structure represents the state of one pipe. A reference to this
* structure is retained in the i_private field of the inode whenthe pipe/fifo
* device is registered.
*/
struct pipe_dev_s
{
sem_t d_bfsem; /* Used to serialize access to d_buffer and indices */
sem_t d_rdsem; /* Empty buffer - Reader waits for data write */
sem_t d_wrsem; /* Full buffer - Writer waits for data read */
pipe_ndx_t d_wrndx; /* Index in d_buffer to save next byte written */
pipe_ndx_t d_rdndx; /* Index in d_buffer to return the next byte read */
uint8_t d_refs; /* References counts on pipe (limited to 255) */
uint8_t d_nwriters; /* Number of reference counts for write access */
uint8_t d_pipeno; /* Pipe minor number */
uint8_t *d_buffer; /* Buffer allocated when device opened */
/* The following is a list if poll structures of threads waiting for
* driver events. The 'struct pollfd' reference for each open is also
* retained in the f_priv field of the 'struct file'.
*/
#ifndef CONFIG_DISABLE_POLL
struct pollfd *d_fds[CONFIG_DEV_PIPE_NPOLLWAITERS];
#endif
};
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
#ifdef __cplusplus
# define EXTERN extern "C"
extern "C" {
#else
# define EXTERN extern
#endif
EXTERN FAR struct pipe_dev_s *pipecommon_allocdev(void);
EXTERN void pipecommon_freedev(FAR struct pipe_dev_s *dev);
EXTERN int pipecommon_open(FAR struct file *filep);
EXTERN int pipecommon_close(FAR struct file *filep);
EXTERN ssize_t pipecommon_read(FAR struct file *, FAR char *, size_t);
EXTERN ssize_t pipecommon_write(FAR struct file *, FAR const char *, size_t);
#ifndef CONFIG_DISABLE_POLL
EXTERN int pipecommon_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup);
#endif
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* CONFIG_DEV_PIPE_SIZE > 0 */
#endif /* __DRIVERS_PIPES_PIPE_COMMON_H */