663 lines
15 KiB
C
663 lines
15 KiB
C
/****************************************************************************
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* fs/vfs/fs_timerfd.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdio.h>
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#include <poll.h>
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#include <assert.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <debug.h>
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#include <nuttx/wdog.h>
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#include <nuttx/mutex.h>
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#include <sys/ioctl.h>
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#include <sys/timerfd.h>
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#include "clock/clock.h"
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#include "inode/inode.h"
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#include "fs_heap.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Types
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****************************************************************************/
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typedef struct timerfd_waiter_sem_s
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{
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sem_t sem;
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FAR struct timerfd_waiter_sem_s *next;
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} timerfd_waiter_sem_t;
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/* This structure describes the internal state of the driver */
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struct timerfd_priv_s
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{
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mutex_t lock; /* Enforces device exclusive access */
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FAR timerfd_waiter_sem_t *rdsems; /* List of blocking readers */
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int clock; /* Clock to use as the timing base */
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int delay; /* If non-zero, used to reset repetitive
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* timers */
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struct wdog_s wdog; /* The watchdog that provides the timing */
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timerfd_t counter; /* timerfd counter */
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uint8_t crefs; /* References counts on timerfd (max: 255) */
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/* The following is a list if poll structures of threads waiting for
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* driver events.
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*/
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#ifdef CONFIG_TIMER_FD_POLL
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FAR struct pollfd *fds[CONFIG_TIMER_FD_NPOLLWAITERS];
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#endif
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};
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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static int timerfd_open(FAR struct file *filep);
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static int timerfd_close(FAR struct file *filep);
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static ssize_t timerfd_read(FAR struct file *filep, FAR char *buffer,
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size_t len);
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#ifdef CONFIG_TIMER_FD_POLL
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static int timerfd_poll(FAR struct file *filep, FAR struct pollfd *fds,
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bool setup);
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#endif
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static int timerfd_blocking_io(FAR struct timerfd_priv_s *dev,
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FAR timerfd_waiter_sem_t *sem,
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FAR timerfd_waiter_sem_t **slist);
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static FAR struct timerfd_priv_s *timerfd_allocdev(void);
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static void timerfd_destroy(FAR struct timerfd_priv_s *dev);
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static void timerfd_timeout(wdparm_t arg);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static const struct file_operations g_timerfd_fops =
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{
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timerfd_open, /* open */
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timerfd_close, /* close */
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timerfd_read, /* read */
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NULL, /* write */
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NULL, /* seek */
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NULL, /* ioctl */
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NULL, /* mmap */
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NULL, /* truncate */
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#ifdef CONFIG_TIMER_FD_POLL
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timerfd_poll /* poll */
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#endif
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};
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static struct inode g_timerfd_inode =
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{
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NULL, /* i_parent */
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NULL, /* i_peer */
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NULL, /* i_child */
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1, /* i_crefs */
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FSNODEFLAG_TYPE_DRIVER, /* i_flags */
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{
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&g_timerfd_fops /* u */
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}
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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static FAR struct timerfd_priv_s *timerfd_allocdev(void)
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{
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FAR struct timerfd_priv_s *dev;
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dev = (FAR struct timerfd_priv_s *)
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fs_heap_zalloc(sizeof(struct timerfd_priv_s));
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if (dev)
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{
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/* Initialize the private structure */
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nxmutex_init(&dev->lock);
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nxmutex_lock(&dev->lock);
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dev->crefs++;
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}
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return dev;
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}
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static void timerfd_destroy(FAR struct timerfd_priv_s *dev)
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{
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wd_cancel(&dev->wdog);
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nxmutex_unlock(&dev->lock);
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nxmutex_destroy(&dev->lock);
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fs_heap_free(dev);
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}
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static int timerfd_open(FAR struct file *filep)
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{
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FAR struct timerfd_priv_s *priv = filep->f_priv;
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int ret;
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/* Get exclusive access to the device structures */
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ret = nxmutex_lock(&priv->lock);
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if (ret < 0)
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{
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return ret;
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}
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if (priv->crefs >= 255)
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{
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/* More than 255 opens; uint8_t would overflow to zero */
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ret = -EMFILE;
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}
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else
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{
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/* Save the new open count on success */
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priv->crefs += 1;
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ret = OK;
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}
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nxmutex_unlock(&priv->lock);
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return ret;
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}
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static int timerfd_close(FAR struct file *filep)
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{
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FAR struct timerfd_priv_s *priv = filep->f_priv;
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int ret;
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/* Get exclusive access to the device structures */
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ret = nxmutex_lock(&priv->lock);
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if (ret < 0)
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{
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return ret;
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}
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/* Decrement the references to the driver. If the reference count will
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* decrement to 0, then uninitialize the driver.
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*/
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if (priv->crefs > 1)
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{
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/* Just decrement the reference count and release the semaphore */
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priv->crefs--;
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nxmutex_unlock(&priv->lock);
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return OK;
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}
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/* Re-create the path to the driver. */
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finfo("destroy\n");
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timerfd_destroy(priv);
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return OK;
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}
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static int timerfd_blocking_io(FAR struct timerfd_priv_s *dev,
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FAR timerfd_waiter_sem_t *sem,
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FAR timerfd_waiter_sem_t **slist)
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{
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int ret;
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sem->next = *slist;
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*slist = sem;
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/* Wait for timerfd to notify */
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ret = nxsem_wait(&sem->sem);
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if (ret < 0)
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{
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FAR timerfd_waiter_sem_t *cur_sem;
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cur_sem = *slist;
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if (cur_sem == sem)
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{
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*slist = sem->next;
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}
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else
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{
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while (cur_sem)
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{
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if (cur_sem->next == sem)
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{
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cur_sem->next = sem->next;
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break;
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}
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}
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}
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}
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return ret;
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}
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static ssize_t timerfd_read(FAR struct file *filep, FAR char *buffer,
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size_t len)
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{
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FAR struct timerfd_priv_s *dev = filep->f_priv;
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irqstate_t intflags;
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ssize_t ret;
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if (len < sizeof(timerfd_t) || buffer == NULL)
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{
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return -EINVAL;
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}
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/* Ensure that interrupts are disabled and we do not lose counts
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* if expiration occurs after read, but before setting counter
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* to zero
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*/
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intflags = enter_critical_section();
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/* Wait for an incoming event */
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if (dev->counter == 0)
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{
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timerfd_waiter_sem_t sem;
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if (filep->f_oflags & O_NONBLOCK)
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{
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leave_critical_section(intflags);
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return -EAGAIN;
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}
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nxsem_init(&sem.sem, 0, 0);
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do
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{
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ret = timerfd_blocking_io(dev, &sem, &dev->rdsems);
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if (ret < 0)
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{
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leave_critical_section(intflags);
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nxsem_destroy(&sem.sem);
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return ret;
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}
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}
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while (dev->counter == 0);
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nxsem_destroy(&sem.sem);
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}
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*(FAR timerfd_t *)buffer = dev->counter;
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dev->counter = 0;
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leave_critical_section(intflags);
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return sizeof(timerfd_t);
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}
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#ifdef CONFIG_TIMER_FD_POLL
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static int timerfd_poll(FAR struct file *filep, FAR struct pollfd *fds,
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bool setup)
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{
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FAR struct timerfd_priv_s *dev = filep->f_priv;
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irqstate_t intflags;
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int ret = OK;
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int i;
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intflags = enter_critical_section();
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if (!setup)
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{
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/* This is a request to tear down the poll. */
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FAR struct pollfd **slot = (FAR struct pollfd **)fds->priv;
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/* Remove all memory of the poll setup */
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*slot = NULL;
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fds->priv = NULL;
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goto out;
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}
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/* This is a request to set up the poll. Find an available
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* slot for the poll structure reference
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*/
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for (i = 0; i < CONFIG_TIMER_FD_NPOLLWAITERS; i++)
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{
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/* Find an available slot */
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if (!dev->fds[i])
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{
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/* Bind the poll structure and this slot */
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dev->fds[i] = fds;
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fds->priv = &dev->fds[i];
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break;
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}
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}
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if (i >= CONFIG_TIMER_FD_NPOLLWAITERS)
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{
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fds->priv = NULL;
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ret = -EBUSY;
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goto out;
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}
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/* Notify the POLLIN event if the counter is not zero */
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if (dev->counter > 0)
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{
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#ifdef CONFIG_TIMER_FD_POLL
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poll_notify(&fds, 1, POLLIN);
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#endif
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}
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out:
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leave_critical_section(intflags);
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return ret;
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}
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#endif
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static void timerfd_timeout(wdparm_t arg)
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{
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FAR struct timerfd_priv_s *dev = (FAR struct timerfd_priv_s *)arg;
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FAR timerfd_waiter_sem_t *cur_sem;
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irqstate_t intflags;
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/* Disable interrupts to ensure that expiration counter is accessed
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* atomically
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*/
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intflags = enter_critical_section();
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/* Increment timer expiration counter */
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dev->counter++;
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/* If this is a repetitive timer, then restart the watchdog */
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if (dev->delay > 0)
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{
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wd_start(&dev->wdog, dev->delay, timerfd_timeout, arg);
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}
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#ifdef CONFIG_TIMER_FD_POLL
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/* Notify all poll/select waiters */
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poll_notify(dev->fds, CONFIG_TIMER_FD_NPOLLWAITERS, POLLIN);
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#endif
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/* Notify all of the waiting readers */
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cur_sem = dev->rdsems;
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while (cur_sem != NULL)
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{
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nxsem_post(&cur_sem->sem);
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cur_sem = cur_sem->next;
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}
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dev->rdsems = NULL;
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leave_critical_section(intflags);
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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int timerfd_create(int clockid, int flags)
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{
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FAR struct timerfd_priv_s *new_dev;
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int new_fd;
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int ret;
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/* Sanity checks. */
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if ((clockid != CLOCK_REALTIME &&
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clockid != CLOCK_MONOTONIC &&
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clockid != CLOCK_BOOTTIME) ||
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(flags & ~(TFD_NONBLOCK | TFD_CLOEXEC)) != 0)
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{
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ret = -EINVAL;
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goto errout;
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}
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/* Allocate instance data for this driver */
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new_dev = timerfd_allocdev();
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if (new_dev == NULL)
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{
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/* Failed to allocate new device */
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ret = -ENOMEM;
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goto errout;
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}
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/* Initialize the timer instance */
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new_dev->clock = clockid;
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new_fd = file_allocate(&g_timerfd_inode, O_RDONLY | flags,
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0, new_dev, 0, true);
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if (new_fd < 0)
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{
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ret = new_fd;
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goto errout_with_dev;
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}
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/* Device is ready for use */
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nxmutex_unlock(&new_dev->lock);
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return new_fd;
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errout_with_dev:
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timerfd_destroy(new_dev);
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errout:
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set_errno(-ret);
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return ERROR;
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}
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int timerfd_settime(int fd, int flags,
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FAR const struct itimerspec *new_value,
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FAR struct itimerspec *old_value)
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{
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FAR struct timerfd_priv_s *dev;
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FAR struct file *filep;
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irqstate_t intflags;
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sclock_t delay;
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int ret;
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/* Some sanity checks */
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if (!new_value)
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{
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ret = -EFAULT;
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goto errout;
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}
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if ((flags & ~TFD_TIMER_ABSTIME) != 0)
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{
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ret = -EINVAL;
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goto errout;
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}
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/* Get file pointer by file descriptor */
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ret = fs_getfilep(fd, &filep);
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if (ret < 0)
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{
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goto errout;
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}
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if (filep->f_inode->u.i_ops != &g_timerfd_fops)
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{
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goto errout_with_filep;
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}
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dev = (FAR struct timerfd_priv_s *)filep->f_priv;
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/* Disable interrupts here to ensure that expiration counter is accessed
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* atomicaly.
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*/
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intflags = enter_critical_section();
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if (old_value)
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{
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/* Get the number of ticks before the underlying watchdog expires */
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delay = wd_gettime(&dev->wdog);
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/* Convert that to a struct timespec and return it */
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clock_ticks2time(&old_value->it_value, delay);
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clock_ticks2time(&old_value->it_interval, dev->delay);
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}
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/* Disarm the timer (in case the timer was already armed when
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* timerfd_settime() is called).
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*/
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wd_cancel(&dev->wdog);
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/* Clear expiration counter */
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dev->counter = 0;
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/* If the it_value member of value is zero, the timer will not be
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* re-armed
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*/
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if (new_value->it_value.tv_sec <= 0 && new_value->it_value.tv_nsec <= 0)
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{
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leave_critical_section(intflags);
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fs_putfilep(filep);
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return OK;
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}
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/* Setup up any repetitive timer */
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delay = clock_time2ticks(&new_value->it_interval);
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dev->delay = delay;
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/* We need to disable timer interrupts through the following section so
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* that the system timer is stable.
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*/
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/* Check if abstime is selected */
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if ((flags & TFD_TIMER_ABSTIME) != 0)
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{
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/* Calculate a delay corresponding to the absolute time in 'value' */
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clock_abstime2ticks(dev->clock, &new_value->it_value, &delay);
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}
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else
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{
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/* Calculate a delay assuming that 'value' holds the relative time
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* to wait. We have internal knowledge that clock_time2ticks always
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* returns success.
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*/
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delay = clock_time2ticks(&new_value->it_value);
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}
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/* If the time is in the past or now, then set up the next interval
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* instead (assuming a repetitive timer).
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*/
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if (delay <= 0)
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{
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delay = dev->delay;
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}
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/* Then start the watchdog */
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ret = wd_start(&dev->wdog, delay, timerfd_timeout, (wdparm_t)dev);
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if (ret < 0)
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{
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leave_critical_section(intflags);
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goto errout_with_filep;
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}
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leave_critical_section(intflags);
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fs_putfilep(filep);
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return OK;
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errout_with_filep:
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fs_putfilep(filep);
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errout:
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set_errno(-ret);
|
|
return ERROR;
|
|
}
|
|
|
|
int timerfd_gettime(int fd, FAR struct itimerspec *curr_value)
|
|
{
|
|
FAR struct timerfd_priv_s *dev;
|
|
FAR struct file *filep;
|
|
sclock_t ticks;
|
|
int ret;
|
|
|
|
/* Some sanity checks */
|
|
|
|
if (!curr_value)
|
|
{
|
|
ret = -EFAULT;
|
|
goto errout;
|
|
}
|
|
|
|
/* Get file pointer by file descriptor */
|
|
|
|
ret = fs_getfilep(fd, &filep);
|
|
if (ret < 0)
|
|
{
|
|
goto errout;
|
|
}
|
|
|
|
if (filep->f_inode->u.i_ops != &g_timerfd_fops)
|
|
{
|
|
fs_putfilep(filep);
|
|
goto errout;
|
|
}
|
|
|
|
dev = (FAR struct timerfd_priv_s *)filep->f_priv;
|
|
|
|
/* Get the number of ticks before the underlying watchdog expires */
|
|
|
|
ticks = wd_gettime(&dev->wdog);
|
|
|
|
/* Convert that to a struct timespec and return it */
|
|
|
|
clock_ticks2time(&curr_value->it_value, ticks);
|
|
clock_ticks2time(&curr_value->it_interval, dev->delay);
|
|
fs_putfilep(filep);
|
|
return OK;
|
|
|
|
errout:
|
|
set_errno(-ret);
|
|
return ERROR;
|
|
}
|