详解Android4.4 RIL短信接收流程分析

 最近有客户反馈Android接收不到短信，于是一头扎进RIL里面找原因。最后发现不是RIL的问题，而是BC72上报
短信的格式不对，AT+CNMA=1无作用等几个小问题导致的。尽管问题不在RIL，但总算把RIL短信接收流程搞清楚了。

接收到新信息的log：

D/ATC ( 1269): AT< +CMT:,27
D/ATC ( 1268): AT< 0891683108705505F0040d91683117358313f500009101329154922307ea31da2c36a301
D/RILJ ( 1792): [UNSL]< UNSOL_RESPONSE_NEW_SMS
D/SmsMessage( 1792): SMS SC address: +8613800755500
V/SmsMessage( 1792): SMS originating address: +8613715338315
V/SmsMessage( 1792): SMS TP-PID:0 data coding scheme: 0
D/SmsMessage( 1792): SMS SC timestamp: 1571831129000
V/SmsMessage( 1792): SMS message body (raw): 'jchfbfh'
D/GsmInboundSmsHandler( 1776): Idle state processing message type 1
D/GsmInboundSmsHandler( 1776): acquired wakelock, leaving Idle state
D/GsmInboundSmsHandler( 1776): entering Delivering state
D/GsmInboundSmsHandler( 1776): URI of new row -> content://raw/3
D/RILJ ( 1775): [3706]> SMS_ACKNOWLEDGE true 0
D/RILC ( 1254): onRequest: SMS_ACKNOWLEDGE
D/ATC ( 1254): AT> AT+CNMA=1
D/ATC ( 1254): AT< OK
D/RILJ ( 1775): [3706]< SMS_ACKNOWLEDGE
D/GsmInboundSmsHandler( 1775): Delivering SMS to: com.android.mms com.android.mms.transaction.PrivilegedSmsReceiver
E/GsmInboundSmsHandler( 1775): unexpected BroadcastReceiver action: android.provider.Telephony.SMS_RECEIVED
D/GsmInboundSmsHandler( 1775): successful broadcast, deleting from raw table.
D/SmsMessage( 2124): SMS SC address: +8613800755500
D/GsmInboundSmsHandler( 1775): Deleted 1 rows from raw table.
D/GsmInboundSmsHandler( 1775): ordered broadcast completed in: 276 ms
D/GsmInboundSmsHandler( 1775): leaving Delivering state
D/GsmInboundSmsHandler( 1775): entering Delivering state
D/GsmInboundSmsHandler( 1775): leaving Delivering state
D/GsmInboundSmsHandler( 1775): entering Idle state
V/SmsMessage( 2124): SMS originating address: +8613715338315
V/SmsMessage( 2124): SMS TP-PID:0 data coding scheme: 0
D/SmsMessage( 2124): SMS SC timestamp: 1572253549000
V/SmsMessage( 2124): SMS message body (raw): 'jchfbfh'
D/GsmInboundSmsHandler( 1775): Idle state processing message type 5
D/GsmInboundSmsHandler( 1775): mWakeLock released

一、短信接收

1. vendor ril接收到modem上报的短信息

hardware/ril/reference-ril/reference-ril.c
static void onUnsolicited (const char *s, const char *sms_pdu)
{
 ... ...
 if (strStartsWith(s, "+CMT:")) {
  RIL_onUnsolicitedResponse (
   RIL_UNSOL_RESPONSE_NEW_SMS, 
   sms_pdu, strlen(sms_pdu)); 
 }
 ... ...
}

2. RILD把短信息发送到RILJ

hardware/ril/libril/ril.cpp
extern "C"
void RIL_onUnsolicitedResponse(int unsolResponse, void *data,
 size_t datalen)
{
 ... ...
 unsolResponseIndex = unsolResponse - RIL_UNSOL_RESPONSE_base; 
 ... ...
 switch (s_unsolResponses[unsolResponseIndex].wakeType) {   
  case WAKE_PARTIAL:
   grabPartialWakeLock();
   shouldScheduleTimeout = true;
  break;
  ... ...
 }
 ... ...
 ret = s_unsolResponses[unsolResponseIndex]      
    .responseFunction(p, data, datalen);
 ... ...
 ret = sendResponse(p);    
}
static UnsolResponseInfo s_unsolResponses[] = { 
... ...

{RIL_UNSOL_RESPONSE_NEW_SMS, responseString, WAKE_PARTIAL},
... ...
}；
static int responseString(Parcel &p, void *response, size_t responselen) {
 
 startResponse;
 appendPrintBuf("%s%s", printBuf, (char*)response);    
 closeResponse;
 writeStringToParcel(p, (const char *)response);     
 return 0;
}

二、解析短信息

1. RILJ获取短信息

frameworks/opt/telephony/src/java/com/android/internal/telephony/RIL.java
private void 
processUnsolicited (Parcel p) { 
 ... ...
 case RIL_UNSOL_RESPONSE_NEW_SMS: ret = responseString(p); break;
 ... ...
 switch(response) {
  ... ...
  case RIL_UNSOL_RESPONSE_NEW_SMS: {
   if (RILJ_LOGD) unsljLog(response);      
   // FIXME this should move up a layer
   String a[] = new String[2];
   a[1] = (String)ret;
   SmsMessage sms;
   sms = SmsMessage.newFromCMT(a);
   if (mGsmSmsRegistrant != null) {
    mGsmSmsRegistrant
     .notifyRegistrant(new AsyncResult(null, sms, null));
   }
   break;
  }
  ... ...
 }
 ... ...
}
private Object
responseString(Parcel p) { 
 String response;
 response = p.readString(); 
 return response;
}

2. 解析短信息

        SmsMessage.newFromCMT(a);根据import android.telephony.SmsMessage，得知代码路径：

frameworks/opt/telephony/src/java/android/telephony/SmsMessage.java
public static SmsMessage newFromCMT(String[] lines) {
 // received SMS in 3GPP format
 SmsMessagebase wrappedMessage =
   com.android.internal.telephony.gsm.SmsMessage.newFromCMT(lines);  
 return new SmsMessage(wrappedMessage);
}
  com.android.internal.telephony.gsm.SmsMessage.newFromCMT(lines)的实现在
frameworks/opt/telephony/src/java/com/android/internal/telephony/gsm/SmsMessage.java
public class SmsMessage extends SmsMessagebase {
 ... ...
 public static SmsMessage newFromCMT(String[] lines) {
  try {
   SmsMessage msg = new SmsMessage();
   msg.parsePdu(IccUtils.hexStringToBytes(lines[1]));    
   return msg;
  } catch (RuntimeException ex) {
   Rlog.e(LOG_TAG, "SMS PDU parsing failed: ", ex);
   return null;
  }
 }
 ... ...
}
  IccUtils.hexStringToBytes(lines[1])把十六进制的字符串转换成字节数组msg.parsePdu()解析这个数组的内容，最后获得短信内容
frameworks/opt/telephony/src/java/com/android/internal/telephony/gsm/SmsMessage.java
private void parsePdu(byte[] pdu) { 
 ... ...
 mScAddress = p.getSCAddress(); 
 if (mScAddress != null) {  
  if (VDBG) Rlog.d(LOG_TAG, "SMS SC address: " + mScAddress);   
 }
 ... ...
 mMti = firstByte & 0x3;
 switch (mMti) {
  ... ...
   case 3: //GSM 03.40 9.2.3.1: MTI == 3 is Reserved.
     //This should be processed in the same way as MTI == 0 (Deliver)
    parseSmsDeliver(p, firstByte);  
    break;
   ... ...
  }
 ... ...
}
private void parseSmsDeliver(PduParser p, int firstByte) {
 ... ...
 mOriginatingAddress = p.getAddress();
 if (mOriginatingAddress != null) {
  if (VDBG) Rlog.v(LOG_TAG, "SMS originating address: "    
    + mOriginatingAddress.address);      
 }
 ... ...
 mProtocolIdentifier = p.getByte();
 // TP-Data-Coding-Scheme
 // see TS 23.038
 mDataCodingScheme = p.getByte();
 if (VDBG) {
  Rlog.v(LOG_TAG, "SMS TP-PID:" + mProtocolIdentifier
    + " data coding scheme: " + mDataCodingScheme);    
 }
 mScTimeMillis = p.getSCTimestampMillis();
 if (VDBG) Rlog.d(LOG_TAG, "SMS SC timestamp: " + mScTimeMillis);   
 boolean hasUserDataHeader = (firstByte & 0x40) == 0x40;
 parseUserData(p, hasUserDataHeader);   
 ... ... 
}  
private void parseUserData(PduParser p, boolean hasUserDataHeader) {
 ... ...
 if (VDBG) Rlog.v(LOG_TAG, "SMS message body (raw): '" + mMessageBody + "'"); 
 ... ...
} 

三、处理短信息    

        对用户有效的短信内容，最终保存在类型为String的mMessageBody变量中，该变量属于SmsMessagebase抽象类，而
SmsMessage继承于SmsMessagebase。
        回到前面frameworks/opt/telephony/src/java/com/android/internal/telephony/RIL.java中processUnsolicited(),
sms = SmsMessage.newFromCMT(a);解析完短信息后，返回一个SmsMessage并通知上层应用。

frameworks/opt/telephony/src/java/com/android/internal/telephony/RIL.java
mGsmSmsRegistrant
 .notifyRegistrant(new AsyncResult(null, sms, null)); 
frameworks/base/core/java/android/os/AsyncResult.java
public class AsyncResult
{
 ... ...
 
 public
 AsyncResult (Object uo, Object r, Throwable ex)
 {
  userObj = uo;
  result = r;
  exception = ex;
 }
 ... ...
}

        根据mGsmSmsRegistrant.notifyRegistrant(new AsyncResult(null, sms, null));找到mGsmSmsRegistrant注册的代码：

frameworks/opt/telephony/src/java/com/android/internal/telephony/baseCommands.java 
public abstract class baseCommands implements CommandsInterface {
 ... ...
 @Override 
 public void setonNewGsmSms(Handler h, int what, Object obj) {   
  mGsmSmsRegistrant = new Registrant (h, what, obj);    
 }
 ... ...
} 

        封装消息EVENT_NEW_SMS消息

frameworks/base/core/java/android/os/Registrant.java
public class Registrant      
{ 
 public
 Registrant(Handler h, int what, Object obj)           
 { 
  refH = new WeakReference(h);   
  this.what = what;     
  userObj = obj;      
 } 
 ... ...
 
 public void
 notifyRegistrant(AsyncResult ar)  
 {
  internalNotifyRegistrant (ar.result, ar.exception);   
 }
  void
 internalNotifyRegistrant (Object result, Throwable exception)  
 {
  Handler h = getHandler();
  if (h == null) {
   clear();
  } else {
   Message msg = Message.obtain();
   msg.what = what;    
   msg.obj = new AsyncResult(userObj, result, exception); 
   h.sendMessage(msg);   
  }
 }
 ... ...
} 

        然而baseCommands是一个抽象类，实现了CommandsInterface中的setOnNewGsmSms接口，这个接口由GsmInboundSmsHandler调用
（phone.mCi.setonNewGsmSms(getHandler(), EVENT_NEW_SMS, null)），也就是说GsmInboundSmsHandler的getHandler()是EVENT_NEW_SMS
的监听者，也就是说frameworks/opt/telephony/src/java/com/android/internal/telephony/RIL.java中mGsmSmsRegistrant.notifyRegistrant(new AsyncResult(null, sms, null))
调用之后，会触发GsmInboundSmsHandler中getHandler()的Handler对EVENT_NEW_SMS消息进行解析。这个Handler肯定是GsmInboundSmsHandler
实例化的对象中的，这个对象在什么时候，在哪里创建的，暂且不管。我们只管EVENT_NEW_SMS这个消息从哪里来，然后到哪里去
就行了。

./frameworks/opt/telephony/src/java/com/android/internal/telephony/ImsSMSDispatcher.java
public final class ImsSMSDispatcher extends SMSDispatcher {
 ... ...
 mGsmInboundSmsHandler = GsmInboundSmsHandler.makeInboundSmsHandler(phone.getContext(),   
   storageMonitor, phone); 
 ... ...
}
./frameworks/opt/telephony/src/java/com/android/internal/telephony/gsm/GsmInboundSmsHandler.java
public class GsmInboundSmsHandler extends InboundSmsHandler {
 ... ...
 
 private GsmInboundSmsHandler(Context context, SmsStorageMonitor storageMonitor,
   Phonebase phone) {
  super("GsmInboundSmsHandler", context, storageMonitor, phone, 
    GsmCellBroadcastHandler.makeGsmCellBroadcastHandler(context, phone));
  phone.mCi.setonNewGsmSms(getHandler(), EVENT_NEW_SMS, null); 
  mDataDownloadHandler = new UsimDataDownloadHandler(phone.mCi);
 }
 ... ...
 
 public static GsmInboundSmsHandler makeInboundSmsHandler(Context context,
   SmsStorageMonitor storageMonitor, Phonebase phone) {
  GsmInboundSmsHandler handler = new GsmInboundSmsHandler(context, storageMonitor, phone); 
  handler.start();     
  return handler;
 }
 ... ...
}
./frameworks/opt/telephony/src/java/com/android/internal/telephony/InboundSmsHandler.java
public abstract class InboundSmsHandler extends StateMachine {
 ... ...
 protected InboundSmsHandler(String name, Context context, SmsStorageMonitor storageMonitor,
   Phonebase phone, CellBroadcastHandler cellBroadcastHandler) {
  ... ...
  addState(mDefaultState);   
  addState(mStartupState, mDefaultState);
  addState(mIdleState, mDefaultState);
  addState(mDeliveringState, mDefaultState);
  addState(mWaitingState, mDeliveringState);
  setInitialState(mStartupState); 
  if (DBG) log("created InboundSmsHandler");
 }
 ... ... 
 class IdleState extends State {
  @Override
  public void enter() {
   if (DBG) log("entering Idle state");
   sendMessageDelayed(EVENT_RELEASE_WAKELOCK, WAKELOCK_TIMEOUT);
  }
  @Override
  public void exit() {
   mWakeLock.acquire();
   if (DBG) log("acquired wakelock, leaving Idle state");
  }
  @Override
  public boolean processMessage(Message msg) {
   if (DBG) log("Idle state processing message type " + msg.what);
   switch (msg.what) {
    case EVENT_NEW_SMS:  
    case EVENT_BROADCAST_SMS:
     deferMessage(msg);
     transitionTo(mDeliveringState);     
     return HANDLED;
    ... ...
   }
  }
 } 
  ... ...
 class DeliveringState extends State { 
  @Override
  public void enter() {
   if (DBG) log("entering Delivering state");
  }
  @Override
  public void exit() {
   if (DBG) log("leaving Delivering state");
  }
  @Override
  public boolean processMessage(Message msg) {
   switch (msg.what) {
    case EVENT_NEW_SMS:
     // handle new SMS from RIL
     handleNewSms((AsyncResult) msg.obj);    
     sendMessage(EVENT_RETURN_TO_IDLE);     
     return HANDLED;
    ... ...
   }
  } 
   ... ...
 }
}
void handleNewSms(AsyncResult ar) {
 ... ...
 SmsMessage sms = (SmsMessage) ar.result;
 result = dispatchMessage(sms.mWrappedSmsMessage);
 ... ...
}
public int dispatchMessage(SmsMessagebase smsb) {
 ... ...
 return dispatchMessageRadioSpecific(smsb);
 ... ...
}

        通过以上流程可以了解到，当状态机接收到SMS后，对消息进行分发，针对type zero, SMS-PP data download,
和3GPP/CPHS MWI type SMS判断，如果是Normal SMS messages，则调用dispatchNormalMessage(smsb)，然后创建
一个InboundSmsTracker对象，把信息保存到raw table，然后在通过sendMessage(EVENT_BROADCAST_SMS, tracker)把消息广播出去。

./frameworks/opt/telephony/src/java/com/android/internal/telephony/InboundSmsHandler.java 


class DeliveringState extends State {
 ... ...
 public boolean processMessage(Message msg) {
  switch (msg.what) {
   ... ...
   case EVENT_BROADCAST_SMS: 
    // if any broadcasts were sent, transition to waiting state
    if (processMessagePart((InboundSmsTracker) msg.obj)) {
     transitionTo(mWaitingState);
    }
    return HANDLED;
   ... ...
  }
 }
 ... ...

}
 
boolean processMessagePart(InboundSmsTracker tracker) {
 ... ...
 BroadcastReceiver resultReceiver = new SmsBroadcastReceiver(tracker);     
 ... ...
 intent = new Intent(Intents.SMS_DELIVER_ACTION);    

 // Direct the intent to only the default SMS app. If we can't find a default SMS app
 // then sent it to all broadcast receivers.
 ComponentName componentName = SmsApplication.getDefaultSmsApplication(mContext, true); 
 if (componentName != null) {
  // Deliver SMS message only to this receiver
  intent.setComponent(componentName);
  log("Delivering SMS to: " + componentName.getPackageName() +
    " " + componentName.getClassName());
 }
 ... ...
 dispatchIntent(intent, android.Manifest.permission.RECEIVE_SMS,
    AppOpsManager.OP_RECEIVE_SMS, resultReceiver);
 ... ...
}

 
private final class SmsBroadcastReceiver extends BroadcastReceiver {
 ... ... 
 public void onReceive(Context context, Intent intent) {
  ... ...
  // Now that the intents have been deleted we can clean up the PDU data.
  if (!Intents.DATA_SMS_RECEIVED_ACTION.equals(action)
    && !Intents.DATA_SMS_RECEIVED_ACTION.equals(action)
    && !Intents.WAP_PUSH_RECEIVED_ACTION.equals(action)) {
   loge("unexpected BroadcastReceiver action: " + action);
  }

  int rc = getResultCode();
  if ((rc != Activity.RESULT_OK) && (rc != Intents.RESULT_SMS_HANDLED)) {
   loge("a broadcast receiver set the result code to " + rc
     + ", deleting from raw table anyway!");
  } else if (DBG) {
   log("successful broadcast, deleting from raw table.");
  }

  deleteFromRawTable(mDeleteWhere, mDeleteWhereArgs);
  sendMessage(EVENT_BROADCAST_COMPLETE);     

  ... ...
 }
 ... ...
}

       到这里，在应用层注册具有Intents.SMS_RECEIVED_ACTION这样action的广播，就可以获取到短信了。

总结

以上所述是小编给大家介绍的Android4.4 RIL短信接收流程分析,希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对考高分网网站的支持！
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