/**************************************************************************** * 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 #include #include #include #include #include #include #include #include #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 */