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, /* 上报UNSOL_RESPONSE_NEW_SMS消息 */
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; /* 找出消息在s_unsolResponses[]的索引 */
... ...
switch (s_unsolResponses[unsolResponseIndex].wakeType) { /* 禁止进入休眠 */
case WAKE_PARTIAL:
grabPartialWakeLock();
shouldScheduleTimeout = true;
break;
... ...
}
... ...
ret = s_unsolResponses[unsolResponseIndex] /* 调用消息处理函数responseString() */
.responseFunction(p, data, datalen);
... ...
ret = sendResponse(p); /* 发送Parcel中的信息内容到服务端RILJ */
}
static UnsolResponseInfo s_unsolResponses[] = {
... ...
/* 消息对应的消息处理函数，新信息到来会唤醒系统 */
{RIL_UNSOL_RESPONSE_NEW_SMS, responseString, WAKE_PARTIAL},
... ...
}；
static int responseString(Parcel &p, void *response, size_t responselen) {
/* one string only */
startResponse;
appendPrintBuf("%s%s", printBuf, (char*)response);
closeResponse;
writeStringToParcel(p, (const char *)response); /* 把字符串格式的信息存到Parcel容器中 */
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); /* 参考log：[UNSL]< UNSOL_RESPONSE_NEW_SMS */
// FIXME this should move up a layer
String a[] = new String[2];
a[1] = (String)ret;
SmsMessage sms;
sms = SmsMessage.newFromCMT(a); /* 解析PDU格式的短信息 */
if (mGsmSmsRegistrant != null) {
mGsmSmsRegistrant
.notifyRegistrant(new AsyncResult(null, sms, null));
}
break;
}
... ...
}
... ...
}
private Object
responseString(Parcel p) {
String response;
response = p.readString(); /* 信息内容转换成Object */
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); /* 是对另一个newFromCMT的封装，因为有gsm和cdma两种短信，
* 即cdma中也有newFromCMT，根据情况按需选择
*/
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])); /* 解析PDU短信 */
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); /* 参考log：SMS SC address: +8613800755500 */
}
... ...
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); /* 对短信类型为Deliver的短信进行解析 */
break;
... ...
}
... ...
}
private void parseSmsDeliver(PduParser p, int firstByte) {
... ...
mOriginatingAddress = p.getAddress();
if (mOriginatingAddress != null) {
if (VDBG) Rlog.v(LOG_TAG, "SMS originating address: " /* 参考log: SMS originating address: +861371533xxxx */
+ 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); /* 参考log: SMS TP-PID:0 data coding scheme: 0 */
}
mScTimeMillis = p.getSCTimestampMillis();
if (VDBG) Rlog.d(LOG_TAG, "SMS SC timestamp: " + mScTimeMillis); /* 参考log：SMS SC timestamp: 1571831129000 */
boolean hasUserDataHeader = (firstByte & 0x40) == 0x40;
parseUserData(p, hasUserDataHeader); /* 解析信息有效内容 */
... ...
}
private void parseUserData(PduParser p, boolean hasUserDataHeader) {
... ...
if (VDBG) Rlog.v(LOG_TAG, "SMS message body (raw): '" + mMessageBody + "'"); /* 短信内容，参考log: SMS message body (raw): 'jchfbfh' */
... ...
}
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)); /* 把sms转成Object类型 */
frameworks/base/core/java/android/os/AsyncResult.java
public class AsyncResult
{
... ...
/** please note, this sets m.obj to be this */
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.notifyRegistrant(new AsyncResult(null, sms, null))中的mGsmSmsRegistrant是在这里创建的 */
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) /* 传入需要处理消息为what的事件处理Handler h，obj为事件内容，参考phone.mCi.setOnNewGsmSms(getHandler(), EVENT_NEW_SMS, null); */
{
refH = new WeakReference(h);
this.what = what;
userObj = obj;
}
... ...
/**
* This makes a copy of @param ar
*/
public void
notifyRegistrant(AsyncResult ar) /* 参考mGsmSmsRegistrant.notifyRegistrant(new AsyncResult(null, sms, null)) */
{
internalNotifyRegistrant (ar.result, ar.exception); /* ar.result为sms */
}
/*package*/ void
internalNotifyRegistrant (Object result, Throwable exception) /* internalNotifyRegistrant (sms, Throwable exception) */
{
Handler h = getHandler();
if (h == null) {
clear();
} else {
Message msg = Message.obtain(); /* 创建一个消息 */
msg.what = what; /* 消息类型EVENT_NEW_SMS */
msg.obj = new AsyncResult(userObj, result, exception); /* 消息内容sms */
h.sendMessage(msg); /* 发送消息到注册了这个消息的Handler，参考phone.mCi.setOnNewGsmSms(getHandler(), EVENT_NEW_SMS, null);的getHandler() */
}
}
... ...
}
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(), /* 获取mGsmInboundSmsHandler，并启动状态机 */
storageMonitor, phone);
... ...
}
./frameworks/opt/telephony/src/java/com/android/internal/telephony/gsm/GsmInboundSmsHandler.java
public class GsmInboundSmsHandler extends InboundSmsHandler {
... ...
/**
* Create a new GSM inbound SMS handler.
*/
private GsmInboundSmsHandler(Context context, SmsStorageMonitor storageMonitor,
PhoneBase phone) {
super("GsmInboundSmsHandler", context, storageMonitor, phone, /* 构造GsmInboundSmsHandler时，通过super()调用InboundSmsHandler的构造函数 */
GsmCellBroadcastHandler.makeGsmCellBroadcastHandler(context, phone));
phone.mCi.setOnNewGsmSms(getHandler(), EVENT_NEW_SMS, null); /* 注册EVENT_NEW_SMS消息 */
mDataDownloadHandler = new UsimDataDownloadHandler(phone.mCi);
}
... ...
/**
* Wait for state machine to enter startup state. We can't send any messages until then.
*/
public static GsmInboundSmsHandler makeInboundSmsHandler(Context context,
SmsStorageMonitor storageMonitor, PhoneBase phone) {
GsmInboundSmsHandler handler = new GsmInboundSmsHandler(context, storageMonitor, phone); /* 实例化GsmInboundSmsHandler */
handler.start(); /* 抽象类InboundSmsHandler继承与StateMachine，而GsmInboundSmsHandler继承于InboundSmsHandler，
* GsmInboundSmsHandler调用启动状态机方法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); /* 构造InboundSmsHandler时，添加状态机的状态 */
addState(mStartupState, mDefaultState);
addState(mIdleState, mDefaultState);
addState(mDeliveringState, mDefaultState);
addState(mWaitingState, mDeliveringState);
setInitialState(mStartupState); /* 初始化状态机 */
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: /* 空闲时，接收到短信 */
case EVENT_BROADCAST_SMS:
deferMessage(msg);
transitionTo(mDeliveringState); /* 转到mDeliveringState */
return HANDLED;
... ...
}
}
}
... ...
class DeliveringState extends State { /* 转到mDeliveringState状态 */
@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); /* 处理新SMS */
sendMessage(EVENT_RETURN_TO_IDLE); /* 处理完回到空闲状态 */
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: /* 接收到EVENT_BROADCAST_SMS消息并处理 */
// 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); /* 创建一个广播接收者，用来处理短信广播的结果 */
... ...
intent = new Intent(Intents.SMS_DELIVER_ACTION); /* 设置当前intent的action为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); /* 这个action只会发送给carrier app，而且carrier app可以通过set result为RESULT_CANCELED来终止这个广播 */
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, /* 广播intent */
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); /* 成功广播 */
... ...
}
... ...
}
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。