/****************************************************************************
* drivers/pipes/pipe.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <assert.h>
#include <errno.h>
#include <nuttx/fs/fs.h>
#include <nuttx/mutex.h>
#include "pipe_common.h"
#if CONFIG_DEV_PIPE_SIZE > 0
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int pipe_close(FAR struct file *filep);
static int pipe_mmap(FAR struct file *filep,
FAR struct mm_map_entry_s *entry);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_pipe_fops =
{
pipecommon_open, /* open */
pipe_close, /* close */
pipecommon_read, /* read */
pipecommon_write, /* write */
NULL, /* seek */
pipecommon_ioctl, /* ioctl */
pipe_mmap, /* mmap */
NULL, /* truncate */
pipecommon_poll /* poll */
};
static mutex_t g_pipelock = NXMUTEX_INITIALIZER;
static int g_pipeno;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: pipe_allocate
****************************************************************************/
static inline int pipe_allocate(void)
{
int ret;
ret = nxmutex_lock(&g_pipelock);
if (ret < 0)
{
return ret;
}
ret = g_pipeno++;
if (g_pipeno < 0)
{
g_pipeno = 0;
}
nxmutex_unlock(&g_pipelock);
return ret;
}
/****************************************************************************
* Name: pipe_close
****************************************************************************/
static int pipe_close(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct pipe_dev_s *dev = inode->i_private;
int ret;
DEBUGASSERT(dev);
/* Perform common close operations */
ret = pipecommon_close(filep);
if (ret == 0 && inode->i_crefs == 1)
{
/* Release the pipe when there are no further open references to it. */
pipecommon_freedev(dev);
}
return ret;
}
/****************************************************************************
* Name: pipe_mmap
****************************************************************************/
static int pipe_mmap(FAR struct file *filep,
FAR struct mm_map_entry_s *entry)
{
UNUSED(filep);
UNUSED(entry);
return -ENODEV;
}
/****************************************************************************
* Name: pipe_register
****************************************************************************/
static int pipe_register(size_t bufsize, int flags,
FAR char *devname, size_t namesize)
{
FAR struct pipe_dev_s *dev;
int pipeno;
int ret;
/* Allocate a minor number for the pipe device */
pipeno = pipe_allocate();
if (pipeno < 0)
{
return pipeno;
}
/* Create a pathname to the pipe device */
snprintf(devname, namesize, CONFIG_DEV_PIPE_VFS_PATH"/%d", pipeno);
/* Allocate and initialize a new device structure instance */
dev = pipecommon_allocdev(bufsize);
if (dev == NULL)
{
return -ENOMEM;
}
/* Register the pipe device */
ret = register_pipedriver(devname, &g_pipe_fops, 0666, (FAR void *)dev);
if (ret != 0)
{
pipecommon_freedev(dev);
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: file_pipe
*
* Description:
* file_pipe() creates a pair of file descriptors, pointing to a pipe
* inode, and places them in the array pointed to by 'filep'. filep[0]
* is for reading, filep[1] is for writing.
*
* Input Parameters:
* filep[2] - The user provided array in which to catch the pipe file
* descriptors
* bufsize - The size of the in-memory, circular buffer in bytes.
* flags - The file status flags.
*
* Returned Value:
* 0 is returned on success; a negated errno value is returned on a
* failure.
*
****************************************************************************/
int file_pipe(FAR struct file *filep[2], size_t bufsize, int flags)
{
char devname[32];
int ret;
bool blocking;
/* Register a new pipe device */
ret = pipe_register(bufsize, flags, devname, sizeof(devname));
if (ret < 0)
{
return ret;
}
/* Check for the O_NONBLOCK bit on flags */
blocking = (flags & O_NONBLOCK) == 0;
/* Get a write file descriptor */
ret = file_open(filep[1], devname, O_WRONLY | O_NONBLOCK | flags);
if (ret < 0)
{
goto errout_with_driver;
}
/* Clear O_NONBLOCK if it was set previously */
if (blocking)
{
ret = file_fcntl(filep[1], F_SETFL, flags & (~O_NONBLOCK));
if (ret < 0)
{
goto errout_with_driver;
}
}
/* Get a read file descriptor */
ret = file_open(filep[0], devname, O_RDONLY | flags);
if (ret < 0)
{
goto errout_with_wrfd;
}
/* Remove the pipe name from file system */
unregister_pipedriver(devname);
return OK;
errout_with_wrfd:
file_close(filep[1]);
errout_with_driver:
unregister_pipedriver(devname);
return ret;
}
/****************************************************************************
* Name: pipe2
*
* Description:
* pipe2() creates a pair of file descriptors, pointing to a pipe inode,
* and places them in the array pointed to by 'fd'. fd[0] is for reading,
* fd[1] is for writing.
*
* Input Parameters:
* fd[2] - The user provided array in which to catch the pipe file
* descriptors
* flags - The file status flags.
*
* Returned Value:
* 0 is returned on success; -1 (ERROR) is returned on a failure
* with the errno value set appropriately.
*
****************************************************************************/
int pipe2(int fd[2], int flags)
{
char devname[32];
int ret;
/* Register a new pipe device */
ret = pipe_register(CONFIG_DEV_PIPE_SIZE, flags, devname, sizeof(devname));
if (ret < 0)
{
set_errno(-ret);
return ERROR;
}
/* Get a write file descriptor setting O_NONBLOCK temporarily */
fd[1] = open(devname, O_WRONLY | O_NONBLOCK | flags);
if (fd[1] < 0)
{
goto errout_with_driver;
}
/* Clear O_NONBLOCK if it was set previously */
if ((flags & O_NONBLOCK) == 0)
{
ret = fcntl(fd[1], F_SETFL, flags & (~O_NONBLOCK));
if (ret < 0)
{
goto errout_with_driver;
}
}
/* Get a read file descriptor */
fd[0] = open(devname, O_RDONLY | flags);
if (fd[0] < 0)
{
goto errout_with_wrfd;
}
/* Remove the pipe name from file system */
unregister_pipedriver(devname);
return OK;
errout_with_wrfd:
nx_close(fd[1]);
errout_with_driver:
unregister_pipedriver(devname);
return ERROR;
}
#endif /* CONFIG_DEV_PIPE_SIZE > 0 */