NITZ time update similar from ntp, but it have time zone, so we start to learn it.
NITZ时间同步流程
sequenceDiagram
sprd_ril->>sprd_libril: RIL_onUnsolicitedResponse
sprd_libril->>sprd_libril: sendResponse
sprd_libril->>RILJ: RIL_UNSOL_NITZ_TIME_RECEIVED
RILJ->>RILJ: setOnNITZTime
RILJ->>GsmServiceStateTracker: EVENT_NITZ_TIME
GsmServiceStateTracker->>GsmServiceStateTracker: setTimeFromNITZString
RILC层
1. 接收到AT上报
++vendor/sprd/proprietories-source/ril/sprd_ril/sprd_ril.c +14034++
static void onUnsolicited (const char *s, const char *sms_pdu)
{
...
14034 if (strStartsWith(s, "+CTZV:")) {
14035 /*NITZ time */
14036 char *response;
14037 char *tmp;
14038 char *raw_str;
14039
14040 line = strdup(s);
14041 tmp = line;
14042 at_tok_start(&tmp);//获取：后的内容
14043
14044 err = at_tok_nextstr(&tmp, &response);//检查是否有多余内容
14045 if (err != 0) {
14046 RILLOGE("invalid NITZ line %s\n", s);
14047 } else {
14048#if defined (GLOBALCONFIG_RIL_SAMSUNG_LIBRIL_INTF_EXTENSION)
14049 raw_str = (char *)malloc(strlen(response) + 1);
14050 memcpy(raw_str, response, strlen(response) + 1)
14051 RIL_requestTimedCallback (onNitzReceived, raw_str, NULL);
14052#elif defined (RIL_SPRD_EXTENSION)
14053 **RIL_onUnsolicitedResponse** (//此函数是指针注册在RILD中
14054 RIL_UNSOL_NITZ_TIME_RECEIVED,//上报给RILJ的ID
14055 response, strlen(response)+1);//response是内容，长度加1是因为不含换行
14056#endif
14057 }
2. RIL_onUnsolicitedResponse处理
++vendor/sprd/proprietories-source/ril/sprd_libril/sprd_ril.c +6322++
6326 int unsolResponseIndex = -1;
6327 int ret;
6328 int64_t timeReceived = 0;
...
6431 // Mark the time this was received, doing this
6432 // after grabing the wakelock incase getting
6433 // the elapsedRealTime might cause us to goto
6434 // sleep.
6435 if (unsolResponse == RIL_UNSOL_NITZ_TIME_RECEIVED) {
6436 timeReceived = elapsedRealtime();//记录此刻系统运行时间，用于校准NITZ时间
6437 }
...
6441 Parcel p;//打包数据给RILJ
6442
6443 p.writeInt32 (RESPONSE_UNSOLICITED);//data 0,上报类型是非主动请求
6444 p.writeInt32 (unsolResponse)//data 1,上报的信息ID
6445
6446 ret = s_unsolResponses[unsolResponseIndex]
6447 .responseFunction(p, data, datalen);//三个技巧用法
...
6468 p.writeInt64(timeReceived)//data 2,系统运行时间
...
6472 ret = **sendResponse(p, socket_type);**
6473 if (ret != 0 && unsolResponse == RIL_UNSOL_NITZ_TIME_RECEIVED) {//这里用于备份NITZ时间
6474
6475 // Unfortunately, NITZ time is not poll/update like everything
6476 // else in the system. So, if the upstream client isn't connected,
6477 // keep a copy of the last NITZ response (with receive time noted
6478 // above) around so we can deliver it when it is connected
...
6484
6485 s_lastNITZTimeData = malloc(p.dataSize());
6486 s_lastNITZTimeDataSize = p.dataSize();
6487 memcpy(s_lastNITZTimeData, p.data(), p.dataSize());
6488 }
...
3. 继续传递
++vendor/sprd/proprietories-source/ril/sprd_libril/sprd_ril.cpp++
2734static int
2735sendResponse (Parcel &p, RIL_SOCKET_TYPE socket_type) {
2736 printResponse;//打印log信息
2737 return sendResponseRaw(p.data(), p.dataSize(), socket_type);//传递打包后的信息
2738}
- 写入节点
++vendor/sprd/proprietories-source/ril/sprd_libril/sprd_ril.cpp++
2687static int 2688sendResponseRaw (const void *data, size_t dataSize, RIL_SOCKET_TYPE socket_type) { 2689 int fd = s_rilSocketParam.fdCommand;//socket节 2690 int ret; ... 2709 pthread_mutex_lock(writeMutex);//加锁 2710 2711 header = htonl(dataSize);//序列话后顺序 2712 2713 ret = blockingWrite(fd, (void *)&header, sizeof(header));//写入size ... 2721 ret = blockingWrite(fd, data, dataSize)//写入data 2728 2729 pthread_mutex_unlock(writeMutex);//解锁 2730 2731 return 0; 2732}
RILJ层
1. 处理上报消息
++frameworks/opt/telephony/src/java/com/android/internal/telephony/RIL.java++
2632 protected void
2633 processUnsolicited (Parcel p) {
...
2637 response = p.readInt();//读出消息ID
2638
...
2653 case RIL_UNSOL_NITZ_TIME_RECEIVED: ret = responseString(p); break;//读出消息字串
...
2797 long nitzReceiveTime = p.readLong()//读出携带的系统运行时间
2798
2799 Object[] result = new Object[2];
2800
2801 result[0] = ret;
2802 result[1] = Long.valueOf(nitzReceiveTime);
2803
...
2807 if (ignoreNitz) {
2808 if (RILJ_LOGD) riljLog("ignoring UNSOL_NITZ_TIME_RECEIVED");
2809 } else {
2810 if (mNITZTimeRegistrant != null) {
2811
2812 **mNITZTimeRegistrant**
2813 .notifyRegistrant(new AsyncResult (null, result, null);//注意mNITZTimeRegistrant的初始化
2814 } else {
2815 // in case NITZ time registrant isnt registered yet
2816 mLastNITZTimeInfo = result;
2817 }
2818 }
2819 break;
2. 观察监听者是如何处理的
++frameworks/opt/telephony/src/java/com/android/internal/telephony/RIL.java++
665 @Override public void
666 setOnNITZTime(Handler h, int what, Object obj) {
667 **super.setOnNITZTime(h, what, obj);**//在父类BaseCommands.java里实例化
668
669 // Send the last NITZ time if we have it
670 if (mLastNITZTimeInfo != null) {
671 mNITZTimeRegistrant
672 .notifyRegistrant(
673 new AsyncResult (null, mLastNITZTimeInfo, null));
674 mLastNITZTimeInfo = null;
675 }
676 }
3. 注册监听的GsmServiceStateTracker
++frameworks/opt/telephony/src/java/com/android/internal/telephony/gsm/GsmServiceStateTracker.java++
252 public GsmServiceStateTracker(GSMPhone phone) {
...
268 mCi.setOnNITZTime(this, EVENT_NITZ_TIME, null);//注册消息事件
...
333 @Override
334 public void handleMessage (Message msg) {
...
450 case EVENT_NITZ_TIME:
451 ar = (AsyncResult) msg.obj;
452
453 String nitzString = (String)((Object[])ar.result)[0];//读出携带的res
454 long nitzReceiveTime = ((Long)((Object[])ar.result)[1]).longValue();//读出携带的系统运行时间
455
456 setTimeFromNITZString(nitzString, nitzReceiveTime);
457 break;
4. 关键的设置时间函
++
1747 /**
1748 * nitzReceiveTime is time_t that the NITZ time was posted
1749 */
1750 private void setTimeFromNITZString (String nitz, long nitzReceiveTime) {
1751 // "yy/mm/dd,hh:mm:ss(+/-)tz"
1752 // tz is in number of quarter-hours
1753
1754 long start = SystemClock.elapsedRealtime();//记录当前系统运行时间
1755 if (DBG) {log("NITZ: " + nitz + "," + nitzReceiveTime +
1756 " start=" + start + " delay=" + (start - nitzReceiveTime));
1757 }
1758
1759 try {
1760 /* NITZ time (hour:min:sec) will be in UTC but it supplies the timezone
1761 * offset as well (which we won't worry about until later) */
1762 Calendar c = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
1763
1764 c.clear();
1765 c.set(Calendar.DST_OFFSET, 0);//夏令时偏移0
1766
1767 String[] nitzSubs = nitz.split("[/:,+-]");
1768
1769 try {
1770 int year = 2000 + Integer.parseInt(nitzSubs[0]);
1771 c.set(Calendar.YEAR, year);
1772
1773 // month is 0 based!
1774 int month = Integer.parseInt(nitzSubs[1]) - 1;
1775 c.set(Calendar.MONTH, month);
1776
1777 int date = Integer.parseInt(nitzSubs[2]);
1778 c.set(Calendar.DATE, date);
1779
1780 int hour = Integer.parseInt(nitzSubs[3]);
1781 c.set(Calendar.HOUR, hour);
1782
1783 int minute = Integer.parseInt(nitzSubs[4]);
1784 c.set(Calendar.MINUTE, minute);
1785
1786 int second = Integer.parseInt(nitzSubs[5]);
1787 c.set(Calendar.SECOND, second);
1788 } catch (NumberFormatException e) {
1789 log("NITZ: time format is incorrect");
1790 // set nitzReceiveTime to an invalid value to bypass the time update
1791 nitzReceiveTime = SystemClock.elapsedRealtime() + 60 * 1000;
1792 }//时间分割完毕
1793
1794 boolean sign = (nitz.indexOf('-') == -1);//时区偏移方向
1795
1796 int tzOffset = Integer.parseInt(nitzSubs[6]);//时区偏移值
1797
1798 int dst = (nitzSubs.length >= 8 ) ? Integer.parseInt(nitzSubs[7])
1799 : 0;//夏令时偏移
1800 if (DBG) log("sign = " + sign + "; tzOffset = " + tzOffset + "; dst = " + dst);
1801
1802 // The zone offset received from NITZ is for current local time,
1803 // so DST correction is already applied. Don't add it again.
1804 //
1805 // tzOffset += dst * 4;
1806 //
1807 // We could unapply it if we wanted the raw offset.
1808
1809 tzOffset = (sign ? 1 : -1) * tzOffset * 15 * 60 * 1000;//时区偏移
1810
1811 TimeZone zone = null;
1812
1813 // As a special extension, the Android emulator appends the name of
1814 // the host computer's timezone to the nitz string. this is zoneinfo
1815 // timezone name of the form Area!Location or Area!Location!SubLocation
1816 // so we need to convert the ! into /
1817 if (nitzSubs.length >= 9) {//转换时区信息
1818 String tzname = nitzSubs[8].replace('!','/');
1819 if (DBG) log("tzname = " + tzname);
1820 zone = TimeZone.getTimeZone( tzname );
1821 }
1822
1823 String operatorIsoCountryProperty = TelephonyManager.getProperty(
1824 TelephonyProperties.PROPERTY_OPERATOR_ISO_COUNTRY, mPhone.getPhoneId());//以下是时区设置
1825 String iso = SystemProperties.get(operatorIsoCountryProperty);
1826
1827 if (DBG) log("iso = " + iso);
1828
1829 if (zone == null) {
1830
1831 if (mGotCountryCode) {
1832 if (iso != null && iso.length() > 0) {
1833 zone = TimeUtils.getTimeZone(tzOffset, dst != 0,
1834 c.getTimeInMillis(),
1835 iso);
1836 } else {
1837 // We don't have a valid iso country code. This is
1838 // most likely because we're on a test network that's
1839 // using a bogus MCC (eg, "001"), so get a TimeZone
1840 // based only on the NITZ parameters.
1841 zone = getNitzTimeZone(tzOffset, (dst != 0), c.getTimeInMillis());
1842 }
1843 }
1844 }
1845
1846 if ((zone == null) || (mZoneOffset != tzOffset) || (mZoneDst != (dst != 0))){
1847 // We got the time before the country or the zone has changed
1848 // so we don't know how to identify the DST rules yet. Save
1849 // the information and hope to fix it up later.
1850
1851 mNeedFixZoneAfterNitz = true;
1852 mZoneOffset = tzOffset;
1853 mZoneDst = dst != 0;
1854 mZoneTime = c.getTimeInMillis();
1855 }
1856
1857 if (zone != null) {
1858 if (getAutoTimeZone()) {
1859 setAndBroadcastNetworkSetTimeZone(zone.getID());
1860 }
1861 saveNitzTimeZone(zone.getID());
1862 }
1863
1864 String ignore = SystemProperties.get("gsm.ignore-nitz");
1865 if (ignore != null && ignore.equals("yes")) {
1866 log("NITZ: Not setting clock because gsm.ignore-nitz is set");
1867 return;
1868 }
1869
1870 try {//处理时间设置
1871 mWakeLock.acquire();
1872
1873 if (getAutoTime()) {
1874 long millisSinceNitzReceived
1875 = SystemClock.elapsedRealtime() - nitzReceiveTime;
1876
1877 if (millisSinceNitzReceived < 0) {
1878 // Sanity check: something is wrong
1879 if (DBG) {
1880 log("NITZ: not setting time, clock has rolled "
1881 + "backwards since NITZ time was received, "
1882 + nitz);
1883 }
1884 return;
1885 }
1886
1887 if (millisSinceNitzReceived > Integer.MAX_VALUE) {
1888 // If the time is this far off, something is wrong > 24 days!
1889 if (DBG) {
1890 log("NITZ: not setting time, processing has taken "
1891 + (millisSinceNitzReceived / (1000 * 60 * 60 * 24))
1892 + " days");
1893 }
1894 return;
1895 }
1896
1897 // Note: with range checks above, cast to int is safe
1898 c.add(Calendar.MILLISECOND, (int)millisSinceNitzReceived);
1899
1900 if (DBG) {
1901 log("NITZ: Setting time of day to " + c.getTime()
1902 + " NITZ receive delay(ms): " + millisSinceNitzReceived
1903 + " gained(ms): "
1904 + (c.getTimeInMillis() - System.currentTimeMillis())
1905 + " from " + nitz);
1906 }
1907
1908 setAndBroadcastNetworkSetTime(c.getTimeInMillis());//此处设置时间
1909 Rlog.i(LOG_TAG, "NITZ: after Setting time of day");
1910 }
1911 SystemProperties.set("gsm.nitz.time", String.valueOf(c.getTimeInMillis()));
1912 saveNitzTime(c.getTimeInMillis());
1913 if (VDBG) {
1914 long end = SystemClock.elapsedRealtime();
1915 log("NITZ: end=" + end + " dur=" + (end - start));
1916 }
1917 mNitzUpdatedTime = true;
1918 } finally {
1919 mWakeLock.release();
1920 }
1921 } catch (RuntimeException ex) {
1922 loge("NITZ: Parsing NITZ time " + nitz + " ex=" + ex);
1923 }
1924 }
...
1974 /**
1975 * Set the time and Send out a sticky broadcast so the system can determine
1976 * if the time was set by the carrier.
1977 *
1978 * @param time time set by network
1979 */
1980 private void setAndBroadcastNetworkSetTime(long time) {
1981 if (DBG) log("setAndBroadcastNetworkSetTime: time=" + time + "ms");
1982 SystemClock.setCurrentTimeMillis(time);//调用AlarmManagerService的setTime设置时间
1983 Intent intent = new Intent(TelephonyIntents.ACTION_NETWORK_SET_TIME);
1984 intent.addFlags(Intent.FLAG_RECEIVER_REPLACE_PENDING);
1985 intent.putExtra("time", time);
1986 mPhone.getContext().sendStickyBroadcastAsUser(intent, UserHandle.ALL);//用于NetworkTimeUpdateService.java记录本次设置的时间
1987 }