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3c486b98dd
Implement Linux-compatible TFD_TIMER_CANCEL_ON_SET flag for timerfd to allow applications to detect discontinuous changes to CLOCK_REALTIME. Background: According to Linux timerfd_create(2) man page, when a timerfd is created with CLOCK_REALTIME and TFD_TIMER_CANCEL_ON_SET flag is specified, the read() operation should fail with ECANCELED if the real-time clock undergoes a discontinuous change. This allows applications to detect and respond to system time changes. Implementation: 1. Add clock notifier infrastructure (clock_notifier.h/c) to notify interested parties when system time changes 2. Implement TFD_TIMER_CANCEL_ON_SET flag support in timerfd 3. Register timerfd with clock notifier when flag is set 4. Cancel timer and return ECANCELED when clock change is detected 5. Notify clock changes in: - clock_settime() - clock_initialize() - clock_timekeeping_set_wall_time() - rpmsg_rtc time synchronization Changes include: - New files: include/nuttx/clock_notifier.h, sched/clock/clock_notifier.c - Modified: fs/vfs/fs_timerfd.c to handle TFD_TIMER_CANCEL_ON_SET - Modified: clock subsystem to call notifier chain on time changes - Modified: rpmsg_rtc to notify time changes during sync Use case example: Applications using timerfd with absolute time can now detect when system time is adjusted (e.g., NTP sync, manual time change) and take appropriate action such as recalculating timeouts or updating scheduled events. Reference: https://man7.org/linux/man-pages/man2/timerfd_create.2.html Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
83 lines
2.6 KiB
C
83 lines
2.6 KiB
C
/****************************************************************************
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* include/sys/timerfd.h
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*
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* SPDX-License-Identifier: Apache-2.0
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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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#ifndef __INCLUDE_SYS_TIMERFD_H
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#define __INCLUDE_SYS_TIMERFD_H
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <stdint.h>
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#include <fcntl.h>
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#include <time.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#define TFD_NONBLOCK O_NONBLOCK
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#define TFD_CLOEXEC O_CLOEXEC
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#define TFD_TIMER_ABSTIME TIMER_ABSTIME
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#define TFD_TIMER_CANCEL_ON_SET 2
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/****************************************************************************
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* Public Type Declarations
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****************************************************************************/
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/* Type for timer counter */
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/* Type for event counter */
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#ifdef __INT64_DEFINED
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typedef uint64_t timerfd_t;
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#else
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typedef uint32_t timerfd_t;
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#endif
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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#ifdef __cplusplus
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#define EXTERN extern "C"
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extern "C"
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{
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#else
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#define EXTERN extern
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#endif
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int timerfd_create(int clockid, int flags);
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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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int timerfd_gettime(int fd, FAR struct itimerspec *curr_value);
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#undef EXTERN
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#ifdef __cplusplus
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}
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#endif
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#endif /* __INCLUDE_SYS_TIMERFD_H */
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