NAME

kysdk-systime - KYLIN SDK System Time Monitoring Service

SYNOPSIS

kysdk-systime

DESCRIPTION

kysdk-systime is a system time monitoring service in the KYLIN SDK system. This service provides real-time system time broadcasting and monitoring capabilities, detecting system time changes and timezone changes, and broadcasting time information through D-Bus signals.

The service runs as a system daemon that continuously monitors the system clock for changes and broadcasts time updates every minute. It also monitors for system time adjustments and timezone changes, ensuring accurate time information is available to all subscribed applications.

FEATURES

Real-time Time Broadcasting: Broadcasts current system time every minute through D-Bus signals
System Time Change Detection: Monitors and detects system time adjustments using timerfd
Timezone Change Monitoring: Monitors changes to system timezone settings using inotify
D-Bus Signal Broadcasting: Provides time information through D-Bus signals for inter-process communication
Precise Timing: Uses high-precision timers for accurate time synchronization

D-Bus INTERFACE

The service implements the following D-Bus interface `com.kylin.kysdk.TimeInterface` with these signals:

TimeSignal: Emitted every minute with current time information in format: "YYYY/MM/DD HH:MM:SS"
TimeChangeSignal: Emitted when system time or timezone changes, providing updated time information

MONITORED EVENTS

System Time Changes: Detects manual time adjustments, NTP synchronization, and other time modifications
Timezone Changes: Monitors changes to /etc/localtime for timezone updates
Clock Drift: Handles clock synchronization and drift correction

THREADING MODEL

The service uses a multi-threaded architecture:

Main Thread: Handles D-Bus communication and main event loop
Time Change Monitor Thread: Monitors system time changes using timerfd
Timezone Monitor Thread: Monitors timezone changes using inotify
Time Broadcast Thread: Manages periodic time broadcasting

TIMER SYSTEM

Periodic Timer: Runs every 60 seconds for regular time broadcasting
Single-shot Timer: Used for immediate time change notifications
Timer Synchronization: Automatically resynchronizes when time changes are detected

FILES

/usr/bin/systime: Main executable file
/etc/systemd/system/kysdk-systime.service: Systemd service configuration file
/etc/localtime: Monitored file for timezone changes

SERVICE

The service runs as a systemd service with: - Service name: kysdk-systime.service - D-Bus name: com.kylin.kysdk.TimeServer - Object path: /com/kylin/kysdk/Timer - Interface: com.kylin.kysdk.TimeInterface - Type: D-Bus activated service

DEPENDENCIES

D-Bus: For inter-process communication
GLib: For main loop integration
libkytimer: For timer management functionality
systemd: For service management

SIGNAL HANDLING

SIGTERM, SIGINT: Graceful shutdown signals
TFD_TIMER_CANCEL_ON_SET: Special timer flag for detecting time changes

TIME FORMATS

All time information is broadcast in the following format: YYYY/MM/DD HH:MM:SS - 4-digit year - 2-digit month (01-12) - 2-digit day (01-31) - 2-digit hour (00-23) - 2-digit minute (00-59) - 2-digit second (00-59)

SYNCHRONIZATION

Automatic Resync: Automatically resynchronizes timers when time changes are detected
Mis-sync Handling: Detects and corrects timing drift or missed notifications
Timer Management: Intelligently manages periodic and single-shot timers

AUTHOR

KylinSoft Co., Ltd.

COPYRIGHT

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.