9、《Laddie报警系统与日志记录详解》

《Laddie报警系统与日志记录详解》

1. Laddie报警系统

Laddie报警系统是一个简单的报警守护进程示例，下面将详细介绍其实现和测试方法。

1.1 报警检测代码

以下是一段用于检测报警状态的代码：

for (i = 0; i < NUM_INPUTS; i++) {
    if (Zone[i].alarm == 1) {
        if (GlobalAlarm == 0) {
            /* A new alarm. Log it and set control bits (low three) high. */
            syslog(LOG_ALERT, "Alarm system status: alarm");
            outb((unsigned char)0x0007, PORT+2);
            GlobalAlarm = 1;
        }
        return;  // in alarm, no need to check the other zones
    }
}
/* If we get here, there are no alarms */
if (GlobalAlarm == 1) {
    /* Clear alarm. Log it and set control bits (low three) low. */
    syslog(LOG_ALERT, "Alarm system status: safe");
    outb((unsigned char)0x