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rt-thread/components/drivers/ipc/pipe.c

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/*
* Copyright (c) 2006-2023, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2012-09-30 Bernard first version.
* 2017-11-08 JasonJiaJie fix memory leak issue when close a pipe.
* 2023-06-28 shell return POLLHUP when writer closed its channel on poll()
* fix flag test on pipe_fops_open()
* 2023-12-02 shell Make read pipe operation interruptable.
*/
#include <rthw.h>
#include <rtdevice.h>
#include <stdint.h>
#include <sys/errno.h>
#include <ipc/condvar.h>
#if defined(RT_USING_POSIX_DEVIO) && defined(RT_USING_POSIX_PIPE)
#include <unistd.h>
#include <fcntl.h>
#include <poll.h>
#include <sys/ioctl.h>
#include <dfs_file.h>
#include <resource_id.h>
/* check RT_UNAMED_PIPE_NUMBER */
#ifndef RT_UNAMED_PIPE_NUMBER
#define RT_UNAMED_PIPE_NUMBER 64
#endif
#define BITS(x) _BITS(x)
#define _BITS(x) (sizeof(#x) - 1)
struct check_rt_unamed_pipe_number
{
/* -4 for "pipe" prefix */
/* -1 for '\0' postfix */
char _check[RT_NAME_MAX - 4 - 1 - BITS(RT_UNAMED_PIPE_NUMBER)];
};
/* check end */
static void *resoure_id[RT_UNAMED_PIPE_NUMBER];
static resource_id_t id_mgr = RESOURCE_ID_INIT(RT_UNAMED_PIPE_NUMBER, resoure_id);
/**
* @brief This function will open a pipe.
*
* @param fd is the file descriptor.
*
* @return Return the operation status.
* When the return value is 0, it means the operation is successful.
* When the return value is -1, it means the file descriptor is invalid.
* When the return value is -RT_ENOMEM, it means insufficient memory allocation failed.
*/
static int pipe_fops_open(struct dfs_file *fd)
{
int rc = 0;
rt_pipe_t *pipe;
pipe = (rt_pipe_t *)fd->vnode->data;
if (!pipe)
{
return -1;
}
rt_mutex_take(&pipe->lock, RT_WAITING_FOREVER);
if ((fd->flags & O_ACCMODE) == O_RDONLY)
{
pipe->reader += 1;
}
if ((fd->flags & O_ACCMODE) == O_WRONLY)
{
pipe->writer += 1;
}
if (fd->vnode->ref_count == 1)
{
pipe->fifo = rt_ringbuffer_create(pipe->bufsz);
if (pipe->fifo == RT_NULL)
{
rc = -RT_ENOMEM;
goto __exit;
}
}
if ((fd->flags & O_ACCMODE) == O_RDONLY && !pipe->writer)
{
/* wait for partner */
rc = rt_condvar_timedwait(&pipe->waitfor_parter, &pipe->lock,
RT_INTERRUPTIBLE, RT_WAITING_FOREVER);
if (rc != 0)
{
pipe->reader--;
}
}
else if ((fd->flags & O_ACCMODE) == O_WRONLY)
{
rt_condvar_broadcast(&pipe->waitfor_parter);
}
__exit:
rt_mutex_release(&pipe->lock);
return rc;
}
/**
* @brief This function will close a pipe.
*
* @param fd is the file descriptor.
*
* @return Return the operation status.
* When the return value is 0, it means the operation is successful.
* When the return value is -1, it means the file descriptor is invalid.
*/
static int pipe_fops_close(struct dfs_file *fd)
{
rt_device_t device;
rt_pipe_t *pipe;
pipe = (rt_pipe_t *)fd->vnode->data;
if (!pipe)
{
return -1;
}
device = &pipe->parent;
rt_mutex_take(&pipe->lock, RT_WAITING_FOREVER);
if ((fd->flags & O_RDONLY) == O_RDONLY)
{
pipe->reader -= 1;
}
if ((fd->flags & O_WRONLY) == O_WRONLY)
{
pipe->writer -= 1;
while (!rt_list_isempty(&pipe->reader_queue.waiting_list))
{
rt_wqueue_wakeup(&pipe->reader_queue, (void*)POLLIN);
}
}
if (fd->vnode->ref_count == 1)
{
if (pipe->fifo != RT_NULL)
{
rt_ringbuffer_destroy(pipe->fifo);
}
pipe->fifo = RT_NULL;
}
rt_mutex_release(&pipe->lock);
if (fd->vnode->ref_count == 1 && pipe->is_named == RT_FALSE)
{
/* delete the unamed pipe */
rt_pipe_delete(device->parent.name);
}
return 0;
}
/**
* @brief This function will get the pipe space size depends on the command.
*
* @param fd is the file descriptor.
*
* @param cmd is the command. It determines what data will get.
*
* FIONREAD The command to get the number of bytes in the pipe.
*
* FIONWRITE The command to get the number of bytes can be written to the pipe.
*
* @param args is the pointer to the data to store the read data.
*
* @return Return the operation status.
* When the return value is 0, it means the operation is successful.
* When the return value is -EINVAL, it means the command is invalid.
*/
static int pipe_fops_ioctl(struct dfs_file *fd, int cmd, void *args)
{
rt_pipe_t *pipe;
int ret = 0;
pipe = (rt_pipe_t *)fd->vnode->data;
switch (cmd)
{
case FIONREAD:
*((int*)args) = rt_ringbuffer_data_len(pipe->fifo);
break;
case FIONWRITE:
*((int*)args) = rt_ringbuffer_space_len(pipe->fifo);
break;
default:
ret = -EINVAL;
break;
}
return ret;
}
/**
* @brief This function will read data from pipe.
*
* @param fd is the file descriptor.
*
* @param buf is the buffer to store the read data.
*
* @param count is the length of data to be read.
*
* @return Return the length of data read.
* When the return value is 0, it means O_NONBLOCK is enabled and there is no thread that has the pipe open for writing.
* When the return value is -EAGAIN, it means there are no data to be read.
*/
#ifdef RT_USING_DFS_V2
static ssize_t pipe_fops_read(struct dfs_file *fd, void *buf, size_t count, off_t *pos)
#else
static ssize_t pipe_fops_read(struct dfs_file *fd, void *buf, size_t count)
#endif
{
int len = 0;
rt_pipe_t *pipe;
pipe = (rt_pipe_t *)fd->vnode->data;
/* no process has the pipe open for writing, return end-of-file */
rt_mutex_take(&pipe->lock, RT_WAITING_FOREVER);
while (1)
{
len = rt_ringbuffer_get(pipe->fifo, buf, count);
if (len > 0 || pipe->writer == 0)
{
break;
}
else
{
if (fd->flags & O_NONBLOCK)
{
len = -EAGAIN;
goto out;
}
rt_mutex_release(&pipe->lock);
rt_wqueue_wakeup(&pipe->writer_queue, (void*)POLLOUT);
if (rt_wqueue_wait_interruptible(&pipe->reader_queue, 0, -1) == -RT_EINTR)
return -EINTR;
rt_mutex_take(&pipe->lock, RT_WAITING_FOREVER);
}
}
/* wakeup writer */
rt_wqueue_wakeup(&pipe->writer_queue, (void*)POLLOUT);
out:
rt_mutex_release(&pipe->lock);
return len;
}
/**
* @brief This function will write data to pipe.
*
* @param fd is the file descriptor.
*
* @param buf is a pointer to the data buffer to be written.
*
* @param count is the length of data to be write.
*
* @return Return the length of data written.
* When the return value is -EAGAIN, it means O_NONBLOCK is enabled and there are no space to be written.
* When the return value is -EPIPE, it means there is no thread that has the pipe open for reading.
*/
#ifdef RT_USING_DFS_V2
static ssize_t pipe_fops_write(struct dfs_file *fd, const void *buf, size_t count, off_t *pos)
#else
static ssize_t pipe_fops_write(struct dfs_file *fd, const void *buf, size_t count)
#endif
{
int len;
rt_pipe_t *pipe;
int wakeup = 0;
int ret = 0;
uint8_t *pbuf;
pipe = (rt_pipe_t *)fd->vnode->data;
if (count == 0)
{
return 0;
}
pbuf = (uint8_t*)buf;
rt_mutex_take(&pipe->lock, -1);
while (1)
{
len = rt_ringbuffer_put(pipe->fifo, pbuf, count - ret);
ret += len;
pbuf += len;
wakeup = 1;
if (ret == count)
{
break;
}
else
{
if (fd->flags & O_NONBLOCK)
{
if (ret == 0)
{
ret = -EAGAIN;
}
break;
}
}
rt_mutex_release(&pipe->lock);
rt_wqueue_wakeup(&pipe->reader_queue, (void*)POLLIN);
/* pipe full, waiting on suspended write list */
if (rt_wqueue_wait_interruptible(&pipe->writer_queue, 0, -1) == -RT_EINTR)
return -EINTR;
rt_mutex_take(&pipe->lock, -1);
}
rt_mutex_release(&pipe->lock);
if (wakeup)
{
rt_wqueue_wakeup(&pipe->reader_queue, (void*)POLLIN);
}
return ret;
}
/**
* @brief This function will get the pipe status.
*
* @param fd is the file descriptor.
*
* @param req is the request type.
*
* @return mask of the pipe status.
* POLLIN means there is data to be read.
* POLLHUP means there is no thread that occupied the pipe to open for writing.
* POLLOUT means there is space to be written.
* POLLERR means there is no thread that occupied the pipe to open for reading.
*/
static int pipe_fops_poll(struct dfs_file *fd, rt_pollreq_t *req)
{
int mask = 0;
rt_pipe_t *pipe;
int mode = 0;
pipe = (rt_pipe_t *)fd->vnode->data;
rt_poll_add(&pipe->reader_queue, req);
rt_poll_add(&pipe->writer_queue, req);
switch (fd->flags & O_ACCMODE)
{
case O_RDONLY:
mode = 1;
break;
case O_WRONLY:
mode = 2;
break;
case O_RDWR:
mode = 3;
break;
}
if (mode & 1)
{
if (rt_ringbuffer_data_len(pipe->fifo) != 0)
{
mask |= POLLIN;
}
else if (pipe->writer == 0)
{
mask = POLLHUP;
}
}
if (mode & 2)
{
if (rt_ringbuffer_space_len(pipe->fifo) != 0)
{
mask |= POLLOUT;
}
}
return mask;
}
static const struct dfs_file_ops pipe_fops =
{
.open = pipe_fops_open,
.close = pipe_fops_close,
.ioctl = pipe_fops_ioctl,
.read = pipe_fops_read,
.write = pipe_fops_write,
.poll = pipe_fops_poll,
};
#endif /* defined(RT_USING_POSIX_DEVIO) && defined(RT_USING_POSIX_PIPE) */
/**
* @brief This function will open the pipe and actually creates the pipe buffer.
*
* @param device is a pointer to the pipe device descriptor.
*
* @param oflag is the open method, but it is not used yet.
*
* @return Return the operation status.
* When the return value is RT_EOK, the operation is successful.
* When the return value is -RT_EINVAL, it means the device handle is empty.
* When the return value is -RT_ENOMEM, it means insufficient memory allocation failed.
*/
rt_err_t rt_pipe_open(rt_device_t device, rt_uint16_t oflag)
{
rt_pipe_t *pipe = (rt_pipe_t *)device;
rt_err_t ret = RT_EOK;
if (device == RT_NULL)
{
ret = -RT_EINVAL;
goto __exit;
}
rt_mutex_take(&pipe->lock, RT_WAITING_FOREVER);
if (pipe->fifo == RT_NULL)
{
pipe->fifo = rt_ringbuffer_create(pipe->bufsz);
if (pipe->fifo == RT_NULL)
{
ret = -RT_ENOMEM;
}
}
rt_mutex_release(&pipe->lock);
__exit:
return ret;
}
/**
* @brief This function will close the pipe and release the pipe buffer.
*
* @param device is a pointer to the pipe device descriptor.
*
* @return Return the operation status.
* When the return value is RT_EOK, the operation is successful.
* When the return value is -RT_EINVAL, it means the device handle is empty.
*/
rt_err_t rt_pipe_close(rt_device_t device)
{
rt_pipe_t *pipe = (rt_pipe_t *)device;
if (device == RT_NULL)
{
return -RT_EINVAL;
}
rt_mutex_take(&pipe->lock, RT_WAITING_FOREVER);
rt_ringbuffer_destroy(pipe->fifo);
pipe->fifo = RT_NULL;
rt_mutex_release(&pipe->lock);
return RT_EOK;
}
/**
* @brief This function will read the specified length of data from the pipe.
*
* @param device is a pointer to the pipe device descriptor.
*
* @param pos is a parameter compatible with POSIX standard interface (currently meaningless, just pass in 0).
*
* @param buffer is a pointer to the buffer to store the read data.
*
* @param count is the length of data to be read.
*
* @return Return the length of data read.
* When the return value is 0, it means the pipe device handle is empty or the count is 0.
*/
rt_ssize_t rt_pipe_read(rt_device_t device, rt_off_t pos, void *buffer, rt_size_t count)
{
uint8_t *pbuf;
rt_size_t read_bytes = 0;
rt_pipe_t *pipe = (rt_pipe_t *)device;
if (device == RT_NULL)
{
rt_set_errno(-EINVAL);
return 0;
}
if (count == 0)
{
return 0;
}
pbuf = (uint8_t*)buffer;
rt_mutex_take(&pipe->lock, RT_WAITING_FOREVER);
while (read_bytes < count)
{
int len = rt_ringbuffer_get(pipe->fifo, &pbuf[read_bytes], count - read_bytes);
if (len <= 0)
{
break;
}
read_bytes += len;
}
rt_mutex_release(&pipe->lock);
return read_bytes;
}
/**
* @brief This function will write the specified length of data to the pipe.
*
* @param device is a pointer to the pipe device descriptor.
*
* @param pos is a parameter compatible with POSIX standard interface (currently meaningless, just pass in 0).
*
* @param buffer is a pointer to the data buffer to be written.
*
* @param count is the length of data to be written.
*
* @return Return the length of data written.
* When the return value is 0, it means the pipe device handle is empty or the count is 0.
*/
rt_ssize_t rt_pipe_write(rt_device_t device, rt_off_t pos, const void *buffer, rt_size_t count)
{
uint8_t *pbuf;
rt_size_t write_bytes = 0;
rt_pipe_t *pipe = (rt_pipe_t *)device;
if (device == RT_NULL)
{
rt_set_errno(-EINVAL);
return 0;
}
if (count == 0)
{
return 0;
}
pbuf = (uint8_t*)buffer;
rt_mutex_take(&pipe->lock, RT_WAITING_FOREVER);
while (write_bytes < count)
{
int len = rt_ringbuffer_put(pipe->fifo, &pbuf[write_bytes], count - write_bytes);
if (len <= 0)
{
break;
}
write_bytes += len;
}
rt_mutex_release(&pipe->lock);
return write_bytes;
}
/**
* @brief This function is not used yet.
*
* @param dev is not used yet.
*
* @param cmd is not used yet.
*
* @param args is not used yet.
*
* @return Always return RT_EOK.
*/
rt_err_t rt_pipe_control(rt_device_t dev, int cmd, void *args)
{
return RT_EOK;
}
#ifdef RT_USING_DEVICE_OPS
const static struct rt_device_ops pipe_ops =
{
RT_NULL,
rt_pipe_open,
rt_pipe_close,
rt_pipe_read,
rt_pipe_write,
rt_pipe_control,
};
#endif /* RT_USING_DEVICE_OPS */
/**
* @brief This function will initialize a pipe device.
* The system allocates a pipe handle from dynamic heap memory, initializes the pipe handle
* with the specified value, and registers the pipe device with the system.
*
* @param name is the name of pipe device.
*
* @param bufsz is the size of pipe buffer.
*
* @return Return the pointer to the pipe device.
* When the return value is RT_NULL, it means the initialization failed.
*/
rt_pipe_t *rt_pipe_create(const char *name, int bufsz)
{
rt_pipe_t *pipe;
rt_device_t dev;
RT_ASSERT(name != RT_NULL);
RT_ASSERT(bufsz < 0xFFFF);
if (rt_device_find(name) != RT_NULL)
{
/* pipe device has been created */
return RT_NULL;
}
pipe = (rt_pipe_t *)rt_malloc(sizeof(rt_pipe_t));
if (pipe == RT_NULL) return RT_NULL;
rt_memset(pipe, 0, sizeof(rt_pipe_t));
pipe->is_named = RT_TRUE; /* initialize as a named pipe */
#if defined(RT_USING_POSIX_DEVIO) && defined(RT_USING_POSIX_PIPE)
pipe->pipeno = -1;
#endif
rt_mutex_init(&pipe->lock, name, RT_IPC_FLAG_FIFO);
rt_wqueue_init(&pipe->reader_queue);
rt_wqueue_init(&pipe->writer_queue);
rt_condvar_init(&pipe->waitfor_parter, "piwfp");
pipe->writer = 0;
pipe->reader = 0;
pipe->bufsz = bufsz;
dev = &pipe->parent;
dev->type = RT_Device_Class_Pipe;
#ifdef RT_USING_DEVICE_OPS
dev->ops = &pipe_ops;
#else
dev->init = RT_NULL;
dev->open = rt_pipe_open;
dev->read = rt_pipe_read;
dev->write = rt_pipe_write;
dev->close = rt_pipe_close;
dev->control = rt_pipe_control;
#endif
dev->rx_indicate = RT_NULL;
dev->tx_complete = RT_NULL;
rt_device_register(&pipe->parent, name, RT_DEVICE_FLAG_RDWR | RT_DEVICE_FLAG_REMOVABLE);
#if defined(RT_USING_POSIX_DEVIO) && defined(RT_USING_POSIX_PIPE)
dev->fops = (void *)&pipe_fops;
#endif
return pipe;
}
/**
* @brief This function will delete a pipe device.
* The system will release the pipe handle and unregister the pipe device from the system.
*
* @param pipe is the pointer to the pipe device.
*
* @return Return the operation status.
* When the return value is 0, it means the operation is successful.
* When the return value is -RT_EINVAL, it means the pipe device is not found or the device isn't a pipe.
* When the return value is -RT_EBUSY, it means the pipe device is busy.
*/
int rt_pipe_delete(const char *name)
{
int result = 0;
rt_device_t device;
device = rt_device_find(name);
if (device)
{
if (device->type == RT_Device_Class_Pipe)
{
rt_pipe_t *pipe;
pipe = (rt_pipe_t *)device;
rt_condvar_detach(&pipe->waitfor_parter);
rt_mutex_detach(&pipe->lock);
#if defined(RT_USING_POSIX_DEVIO) && defined(RT_USING_POSIX_PIPE)
resource_id_put(&id_mgr, pipe->pipeno);
#endif
rt_device_unregister(device);
/* close fifo ringbuffer */
if (pipe->fifo)
{
rt_ringbuffer_destroy(pipe->fifo);
pipe->fifo = RT_NULL;
}
rt_free(pipe);
}
else
{
result = -ENODEV;
}
}
else
{
result = -ENODEV;
}
return result;
}
#if defined(RT_USING_POSIX_DEVIO) && defined(RT_USING_POSIX_PIPE)
/**
* @brief This function will creat a anonymous pipe.
*
* @param fildes[0] is the read handle.
* fildes[1] is the write handle.
*
* @return Return the operation status.
* When the return value is 0, it means the operation is successful.
* When the return value is -1, it means the operation is failed.
*/
int pipe(int fildes[2])
{
rt_pipe_t *pipe;
char dname[8];
char dev_name[32];
int pipeno = 0;
pipeno = resource_id_get(&id_mgr);
if (pipeno == -1)
{
return -1;
}
rt_snprintf(dname, sizeof(dname), "pipe%d", pipeno);
pipe = rt_pipe_create(dname, RT_USING_POSIX_PIPE_SIZE);
if (pipe == RT_NULL)
{
resource_id_put(&id_mgr, pipeno);
return -1;
}
pipe->is_named = RT_FALSE; /* unamed pipe */
pipe->pipeno = pipeno;
rt_snprintf(dev_name, sizeof(dev_name), "/dev/%s", dname);
fildes[1] = open(dev_name, O_WRONLY, 0);
if (fildes[1] < 0)
{
rt_pipe_delete(dname);
return -1;
}
fildes[0] = open(dev_name, O_RDONLY, 0);
if (fildes[0] < 0)
{
close(fildes[1]);
rt_pipe_delete(dname);
return -1;
}
return 0;
}
/**
* @brief This function will create a named pipe.
*
* @param path is the name of pipe device.
*
* @param mode is not used yet.
*
* @return Return the operation status.
* When the return value is 0, it means the operation is successful.
* When the return value is -1, it means the operation is failed.
*/
int mkfifo(const char *path, mode_t mode)
{
rt_pipe_t *pipe;
pipe = rt_pipe_create(path, RT_USING_POSIX_PIPE_SIZE);
if (pipe == RT_NULL)
{
return -1;
}
return 0;
}
#endif /* defined(RT_USING_POSIX_DEVIO) && defined(RT_USING_POSIX_PIPE) */
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