广播相关学习-processNextBroadcast逻辑
2018-12-19 本文已影响0人
weiinter105
下面梳理下processNextBroadcast的相关逻辑
BroadcastQueue#processNextBroadcast
854 //add arg parallelOnce if true, process one broadcast
855 void processNextBroadcast(boolean fromMsg) {
856 processNextBrBroadcastQueue#processNextBroadcast
854 //add arg parallelOnce if true, process one broadcast
855 void processNextBroadcast(boolean fromMsg) {
856 processNextBroadcast(fromMsg, false);
857 }
858
859 void processNextBroadcast(boolean fromMsg, boolean parallelOnce) {
860 synchronized (mService) {
861 processNextBroadcastLocked(fromMsg, false, parallelOnce);
862 }
863 }
864
865 final void processNextBroadcastLocked(boolean fromMsg, boolean skipOomAdj) {
866 processNextBroadcastLocked(fromMsg, skipOomAdj, false);
867 }
868
869 final void processNextBroadcastLocked(boolean fromMsg, boolean skipOomAdj, boolean parallelOnce) {
870
871 BroadcastRecord r;
872
873 if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, "processNextBroadcast ["
874 + mQueueName + "]: "
875 + mParallelBroadcasts.size() + " parallel broadcasts, "
876 + mOrderedBroadcasts.size() + " ordered broadcasts");
877
878 mService.updateCpuStats();
879
880 if (fromMsg) {
881 mBroadcastsScheduled = false; //当这个消息还在队列中时，mBroadcastsScheduled为true;
//当消息开始执行时，这个值为false；那么就又可以发送消息BROADCAST_INTENT_MSG了；等到这个消息执行完了，就又会取出下面的消息依次执行
882 }
883
884 // First, deliver any non-serialized broadcasts right away.
//首先处理并行广播
885 while (mParallelBroadcasts.size() > 0) {
886 r = mParallelBroadcasts.remove(0);
887 r.dispatchTime = SystemClock.uptimeMillis(); //对于串行广播的dispatchTime，就是
888 r.dispatchClockTime = System.currentTimeMillis();//记录广播的分发时间（分发时间-入队时间 = BROADCAST_INTENT_MSG消息的等待时间）
889
890 if (Trace.isTagEnabled(Trace.TRACE_TAG_ACTIVITY_MANAGER)) {
891 Trace.asyncTraceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER,
892 createBroadcastTraceTitle(r, BroadcastRecord.DELIVERY_PENDING),
893 System.identityHashCode(r));
894 Trace.asyncTraceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER,
895 createBroadcastTraceTitle(r, BroadcastRecord.DELIVERY_DELIVERED),
896 System.identityHashCode(r));
897 }
898
899 final int N = r.receivers.size();
900 if (DEBUG_BROADCAST_LIGHT) Slog.v(TAG_BROADCAST, "Processing parallel broadcast ["
901 + mQueueName + "] " + r);
902 for (int i=0; i<N; i++) {
903 Object target = r.receivers.get(i);
904 if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST,
905 "Delivering non-ordered on [" + mQueueName + "] to registered "
906 + target + ": " + r);
907 deliverToRegisteredReceiverLocked(r, (BroadcastFilter)target, false, i); //对并行广播的每个动态接收者，调用deliverToRegisteredReceiverLocked
908 }
909 addBroadcastToHistoryLocked(r); //将处理过的broadcast加入到历史记录中
910 if (DEBUG_BROADCAST_LIGHT) Slog.v(TAG_BROADCAST, "Done with parallel broadcast ["
911 + mQueueName + "] " + r);
919 }
920
921 // Now take care of the next serialized one...
922
923 // If we are waiting for a process to come up to handle the next
924 // broadcast, then do nothing at this point. Just in case, we
925 // check that the process we're waiting for still exists.
//开始处理有序广播或者静态注册的receiver
// 对于有序或静态广播而言，需要依次向每个BroadcastReceiver发送广播，前一个处理完毕后才能发送下一个广播
// 如果BroadcastReceiver对应的进程还未启动，则需要等待
// mPendingBroadcast就是用于保存，因为对应进程还未启动，而处于等待状态的BroadcastRecord
926 if (mPendingBroadcast != null) {
927 if (DEBUG_BROADCAST_LIGHT) Slog.v(TAG_BROADCAST,
928 "processNextBroadcast [" + mQueueName + "]: waiting for "
929 + mPendingBroadcast.curApp);
930
931 boolean isDead;
932 if (mPendingBroadcast.curApp.pid > 0) {
//通过AMS得到对应进程的信息
//BroadRecord对应多个BroadcastReceiver，即对应多个进程
//此处curApp保存当前正在等待的进程
933 synchronized (mService.mPidsSelfLocked) {
934 ProcessRecord proc = mService.mPidsSelfLocked.get(
935 mPendingBroadcast.curApp.pid);
936 isDead = proc == null || proc.crashing;
937 }
938 } else {
939 final ProcessRecord proc = mService.mProcessNames.get(
940 mPendingBroadcast.curApp.processName, mPendingBroadcast.curApp.uid);
941 isDead = proc == null || !proc.pendingStart;
942 }
943 if (!isDead) {
944 // It's still alive, so keep waiting
// 注意到有序和静态广播必须依次处理
// 因此，若前一个BroadcastRecord对应的某个进程启动较慢，不仅会影响该BroadcastRecord中后续进程接收广播
// 还会影响到后续所有BroadcastRecord对应进程接收广播
945 return;
946 } else {
947 Slog.w(TAG, "pending app ["
948 + mQueueName + "]" + mPendingBroadcast.curApp
949 + " died before responding to broadcast");
950 mPendingBroadcast.state = BroadcastRecord.IDLE;
951 mPendingBroadcast.nextReceiver = mPendingBroadcastRecvIndex;
952 mPendingBroadcast = null;
953 }
954 }
955
956 boolean looped = false;
957
958 do {
959 if (mOrderedBroadcasts.size() == 0) {
//没有串行广播等待处理了，那么就可以return了
960 // No more broadcasts pending, so all done!
961 mService.scheduleAppGcsLocked();
962 if (looped) {
963 // If we had finished the last ordered broadcast, then
964 // make sure all processes have correct oom and sched
965 // adjustments.
// 因为静态广播和有序广播，可能拉起进程
// 因此这些广播处理完毕后，AMS需要释放掉一些不需要的进程
966 mService.updateOomAdjLocked();
967 }
968 return;
969 }
970 r = mOrderedBroadcasts.get(0); //取出串行队列中的第一个broadcastRecord
971 boolean forceReceive = false;
972
973 // Ensure that even if something goes awry with the timeout
974 // detection, we catch "hung" broadcasts here, discard them,
975 // and continue to make progress.
976 //
977 // This is only done if the system is ready so that PRE_BOOT_COMPLETED
978 // receivers don't get executed with timeouts. They're intended for
979 // one time heavy lifting after system upgrades and can take
980 // significant amounts of time.
981 int numReceivers = (r.receivers != null) ? r.receivers.size() : 0;
// 这里用于判断此广播是否处理超时
// 仅在系统启动完毕后，才进行该判断，因为PRE_BOOT_COMPLETED广播可能由于系统升级需要等待较长时间
982 if (mService.mProcessesReady && r.dispatchTime > 0) {
983 long now = SystemClock.uptimeMillis();
984 if ((numReceivers > 0) &&
985 (now > r.dispatchTime + (2*mTimeoutPeriod*numReceivers))) {
//单个广播处理的超时时间，定义为2 * 每个接收者处理的最长时间（10s）* 接收者的数量
986 Slog.w(TAG, "Hung broadcast ["
987 + mQueueName + "] discarded after timeout failure:"
988 + " now=" + now
989 + " dispatchTime=" + r.dispatchTime
990 + " startTime=" + r.receiverTime
991 + " intent=" + r.intent
992 + " numReceivers=" + numReceivers
993 + " nextReceiver=" + r.nextReceiver
994 + " state=" + r.state);
995 broadcastTimeoutLocked(false); // forcibly finish this broadcast //直接调用broadcastTimeoutLocked时，参数为false
996 forceReceive = true;
997 r.state = BroadcastRecord.IDLE; //强制结束这条广播
//BroadcastRecord状态为idle时代表当前receiver或者整个BroadcastRecord处理完了，可以处理下一个了
998 }
999 }
1000
1001 if (r.state != BroadcastRecord.IDLE) {
1002 if (DEBUG_BROADCAST) Slog.d(TAG_BROADCAST,
1003 "processNextBroadcast("
1004 + mQueueName + ") called when not idle (state="
1005 + r.state + ")");
1006 return;
1007 }
1008
1009 if (r.receivers == null || r.nextReceiver >= numReceivers
1010 || r.resultAbort || forceReceive) {
//receiver处理完了，或者broadcastRecord强制结束，都代表该broadcast处理完了
1011 // No more receivers for this broadcast! Send the final
1012 // result if requested...
1013 if (r.resultTo != null) {
//当广播执行完或者强制取消的时候，将结果返回给r.resultTo
1014 try {
1015 if (DEBUG_BROADCAST) Slog.i(TAG_BROADCAST,
1016 "Finishing broadcast [" + mQueueName + "] "
1017 + r.intent.getAction() + " app=" + r.callerApp);
1018 performReceiveLocked(r.callerApp, r.resultTo,
1019 new Intent(r.intent), r.resultCode,
1020 r.resultData, r.resultExtras, false, false, r.userId);
1021 // Set this to null so that the reference
1022 // (local and remote) isn't kept in the mBroadcastHistory.
1023 r.resultTo = null;
1024 } catch (RemoteException e) {
1025 r.resultTo = null;
1026 Slog.w(TAG, "Failure ["
1027 + mQueueName + "] sending broadcast result of "
1028 + r.intent, e);
1029
1030 }
1031 }
1032
1033 if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, "Cancelling BROADCAST_TIMEOUT_MSG");
1034 cancelBroadcastTimeoutLocked(); //广播确实执行完了，或者强制结束了，那么就cancelBroadcastTimeoutLocked；但如果是因为超时被强制执行的，当时的receiver进程的app process已经ANR了，这个其实没用
1035
1036 if (DEBUG_BROADCAST_LIGHT) Slog.v(TAG_BROADCAST,
1037 "Finished with ordered broadcast " + r);
1038
1039 // ... and on to the next...
1040 addBroadcastToHistoryLocked(r);
1041 if (r.intent.getComponent() == null && r.intent.getPackage() == null
1042 && (r.intent.getFlags()&Intent.FLAG_RECEIVER_REGISTERED_ONLY) == 0) {
1043 // This was an implicit broadcast... let's record it for posterity.
1044 mService.addBroadcastStatLocked(r.intent.getAction(), r.callerPackage,
1045 r.manifestCount, r.manifestSkipCount, r.finishTime-r.dispatchTime);
1046 }
1047 mOrderedBroadcasts.remove(0);
1048 r = null;
1049 looped = true; //将r置为null,looped置为true；进行以下轮循环，取出下一个串行队列中的广播
1050 continue;
1051 }
1052 } while (r == null);
1053
//上面的流程是找到串行队列中第一个BroadcastRecord，下面处理其中的receiver
1054 // Get the next receiver...
1055 int recIdx = r.nextReceiver++;
1056
1057 // Keep track of when this receiver started, and make sure there
1058 // is a timeout message pending to kill it if need be.
1059 r.receiverTime = SystemClock.uptimeMillis(); //对于串行广播而言，每当传递到一个新的receiver时都更新下receiverTime
1060 if (recIdx == 0) {
1061 r.dispatchTime = r.receiverTime; //取出广播的第一个receiver时，就是广播的BroadcastRecord相应的dispatchTime
1062 r.dispatchClockTime = System.currentTimeMillis();
1063 if (Trace.isTagEnabled(Trace.TRACE_TAG_ACTIVITY_MANAGER)) {
1064 Trace.asyncTraceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER,
1065 createBroadcastTraceTitle(r, BroadcastRecord.DELIVERY_PENDING),
1066 System.identityHashCode(r));
1067 Trace.asyncTraceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER,
1068 createBroadcastTraceTitle(r, BroadcastRecord.DELIVERY_DELIVERED),
1069 System.identityHashCode(r));
1070 }
1071 if (DEBUG_BROADCAST_LIGHT) Slog.v(TAG_BROADCAST, "Processing ordered broadcast ["
1072 + mQueueName + "] " + r);
1073 }
1074 if (! mPendingBroadcastTimeoutMessage) { //mPendingBroadcastTimeoutMessage = true代表当前已经有BROADCAST_TIMEOUT_MSG消息了，无需再重复发送了
1075 long timeoutTime = r.receiverTime + mTimeoutPeriod;
1076 if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST,
1077 "Submitting BROADCAST_TIMEOUT_MSG ["
1078 + mQueueName + "] for " + r + " at " + timeoutTime);
1079 setBroadcastTimeoutLocked(timeoutTime); //针对BroadcastReceiver发送超时消息
1080 }
1081
1082 final BroadcastOptions brOptions = r.options;
1083 final Object nextReceiver = r.receivers.get(recIdx); //得到待处理的receiver
1084
1085 if (nextReceiver instanceof BroadcastFilter) {
//receiver是动态注册的
1086 // Simple case: this is a registered receiver who gets
1087 // a direct call.
1088 BroadcastFilter filter = (BroadcastFilter)nextReceiver;
1089 if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST,
1090 "Delivering ordered ["
1091 + mQueueName + "] to registered "
1092 + filter + ": " + r);
1093 deliverToRegisteredReceiverLocked(r, filter, r.ordered, recIdx); //调用deliverToRegisteredReceiverLocked处理该动态注册receiver
1094 if (r.receiver == null || !r.ordered) {
1095 // The receiver has already finished, so schedule to
1096 // process the next one. //在处理广播的过程performReceiveLocked中，如果receiver所在进程被kill，则会将r.receiver = null; r.curFilter = null;
1097 if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST, "Quick finishing ["
1098 + mQueueName + "]: ordered="
1099 + r.ordered + " receiver=" + r.receiver);
1100 r.state = BroadcastRecord.IDLE; //将当前的状态置为IDLE
1101 scheduleBroadcastsLocked(); //触发下一轮处理过程
1102 } else {
//处理特殊的选项
//向DeviceIdleController发送消息，赋予白名单内的应用，
//在Doze模式的激活窗口中，额外的可以访问网络和持锁的时间(后续再调研)
1103 if (brOptions != null && brOptions.getTemporaryAppWhitelistDuration() > 0) { //参考BroadcastOptions
1104 scheduleTempWhitelistLocked(filter.owningUid,
1105 brOptions.getTemporaryAppWhitelistDuration(), r);
1106 }
1107 }
1108 return;
1109 }
1110
1111 // Hard case: need to instantiate the receiver, possibly
1112 // starting its application process to host it.
1113
1114 ResolveInfo info =
1115 (ResolveInfo)nextReceiver;
1116 ComponentName component = new ComponentName(
1117 info.activityInfo.applicationInfo.packageName,
1118 info.activityInfo.name); //静态注册广播的处理
1119
1120 boolean skip = false;
1121 if (brOptions != null &&
1122 (info.activityInfo.applicationInfo.targetSdkVersion
1123 < brOptions.getMinManifestReceiverApiLevel() ||
1124 info.activityInfo.applicationInfo.targetSdkVersion
1125 > brOptions.getMaxManifestReceiverApiLevel())) {
1126 skip = true;
1127 }
1128 int perm = mService.checkComponentPermission(info.activityInfo.permission,
1129 r.callingPid, r.callingUid, info.activityInfo.applicationInfo.uid,
1130 info.activityInfo.exported);
1131 if (!skip && perm != PackageManager.PERMISSION_GRANTED) {
1132 if (!info.activityInfo.exported) {
1133 Slog.w(TAG, "Permission Denial: broadcasting "
1134 + r.intent.toString()
1135 + " from " + r.callerPackage + " (pid=" + r.callingPid
1136 + ", uid=" + r.callingUid + ")"
1137 + " is not exported from uid " + info.activityInfo.applicationInfo.uid
1138 + " due to receiver " + component.flattenToShortString());
1139 } else {
1140 Slog.w(TAG, "Permission Denial: broadcasting "
1141 + r.intent.toString()
1142 + " from " + r.callerPackage + " (pid=" + r.callingPid
1143 + ", uid=" + r.callingUid + ")"
1144 + " requires " + info.activityInfo.permission
1145 + " due to receiver " + component.flattenToShortString());
1146 }
1147 skip = true;
1148 } else if (!skip && info.activityInfo.permission != null) {
1149 final int opCode = AppOpsManager.permissionToOpCode(info.activityInfo.permission);
1150 if (opCode != AppOpsManager.OP_NONE
1151 && mService.mAppOpsService.noteOperation(opCode, r.callingUid,
1152 r.callerPackage) != AppOpsManager.MODE_ALLOWED) {
1153 Slog.w(TAG, "Appop Denial: broadcasting "
1154 + r.intent.toString()
1155 + " from " + r.callerPackage + " (pid="
1156 + r.callingPid + ", uid=" + r.callingUid + ")"
1157 + " requires appop " + AppOpsManager.permissionToOp(
1158 info.activityInfo.permission)
1159 + " due to registered receiver "
1160 + component.flattenToShortString());
1161 skip = true;
1162 }
1163 }
1164 if (!skip && info.activityInfo.applicationInfo.uid != Process.SYSTEM_UID &&
1165 r.requiredPermissions != null && r.requiredPermissions.length > 0) {
1166 for (int i = 0; i < r.requiredPermissions.length; i++) {
1167 String requiredPermission = r.requiredPermissions[i];
1168 try {
1169 perm = AppGlobals.getPackageManager().
1170 checkPermission(requiredPermission,
1171 info.activityInfo.applicationInfo.packageName,
1172 UserHandle
1173 .getUserId(info.activityInfo.applicationInfo.uid));
1174 } catch (RemoteException e) {
1175 perm = PackageManager.PERMISSION_DENIED;
1176 }
1177 if (perm != PackageManager.PERMISSION_GRANTED) {
1178 Slog.w(TAG, "Permission Denial: receiving "
1179 + r.intent + " to "
1180 + component.flattenToShortString()
1181 + " requires " + requiredPermission
1182 + " due to sender " + r.callerPackage
1183 + " (uid " + r.callingUid + ")");
1184 skip = true;
1185 break;
1186 }
1187 int appOp = AppOpsManager.permissionToOpCode(requiredPermission);
1188 if (appOp != AppOpsManager.OP_NONE && appOp != r.appOp
1192 && mService.mAppOpsService.checkOperation(appOp,
1193 info.activityInfo.applicationInfo.uid, info.activityInfo.packageName)
1195 != AppOpsManager.MODE_ALLOWED) {
1196 Slog.w(TAG, "Appop Denial: receiving "
1197 + r.intent + " to "
1198 + component.flattenToShortString()
1199 + " requires appop " + AppOpsManager.permissionToOp(
1200 requiredPermission)
1201 + " due to sender " + r.callerPackage
1202 + " (uid " + r.callingUid + ")");
1203 skip = true;
1204 break;
1205 }
1206 }
1207 }
1208 if (!skip && r.appOp != AppOpsManager.OP_NONE
1215 != AppOpsManager.MODE_ALLOWED) {
1216 Slog.w(TAG, "Appop Denial: receiving "
1217 + r.intent + " to "
1218 + component.flattenToShortString()
1219 + " requires appop " + AppOpsManager.opToName(r.appOp)
1220 + " due to sender " + r.callerPackage
1221 + " (uid " + r.callingUid + ")");
1222 skip = true;
1223 }
1229 if (!skip) {
1230 skip = !mService.mIntentFirewall.checkBroadcast(r.intent, r.callingUid,
1231 r.callingPid, r.resolvedType, info.activityInfo.applicationInfo.uid);
1232 }
1233 boolean isSingleton = false;
1234 try {
1235 isSingleton = mService.isSingleton(info.activityInfo.processName,
1236 info.activityInfo.applicationInfo,
1237 info.activityInfo.name, info.activityInfo.flags);
1238 } catch (SecurityException e) {
1239 Slog.w(TAG, e.getMessage());
1240 skip = true;
1241 }
1242 if ((info.activityInfo.flags&ActivityInfo.FLAG_SINGLE_USER) != 0) {
1243 if (ActivityManager.checkUidPermission(
1244 android.Manifest.permission.INTERACT_ACROSS_USERS,
1245 info.activityInfo.applicationInfo.uid)
1246 != PackageManager.PERMISSION_GRANTED) {
1247 Slog.w(TAG, "Permission Denial: Receiver " + component.flattenToShortString()
1248 + " requests FLAG_SINGLE_USER, but app does not hold "
1249 + android.Manifest.permission.INTERACT_ACROSS_USERS);
1250 skip = true;
1251 }
1252 }
1253 if (!skip && info.activityInfo.applicationInfo.isInstantApp()
1254 && r.callingUid != info.activityInfo.applicationInfo.uid) {
1255 Slog.w(TAG, "Instant App Denial: receiving "
1256 + r.intent
1257 + " to " + component.flattenToShortString()
1258 + " due to sender " + r.callerPackage
1259 + " (uid " + r.callingUid + ")"
1260 + " Instant Apps do not support manifest receivers");
1261 skip = true;
1262 }
1263 if (!skip && r.callerInstantApp
1264 && (info.activityInfo.flags & ActivityInfo.FLAG_VISIBLE_TO_INSTANT_APP) == 0
1265 && r.callingUid != info.activityInfo.applicationInfo.uid) {
1266 Slog.w(TAG, "Instant App Denial: receiving "
1267 + r.intent
1268 + " to " + component.flattenToShortString()
1269 + " requires receiver have visibleToInstantApps set"
1270 + " due to sender " + r.callerPackage
1271 + " (uid " + r.callingUid + ")");
1272 skip = true;
1273 }
1274 if (r.curApp != null && r.curApp.crashing) {
1275 // If the target process is crashing, just skip it.
1276 Slog.w(TAG, "Skipping deliver ordered [" + mQueueName + "] " + r
1277 + " to " + r.curApp + ": process crashing");
1278 skip = true;
1279 }
1280 if (!skip) {
1281 boolean isAvailable = false;
1282 try {
1283 isAvailable = AppGlobals.getPackageManager().isPackageAvailable(
1284 info.activityInfo.packageName,
1285 UserHandle.getUserId(info.activityInfo.applicationInfo.uid));
1286 } catch (Exception e) {
1287 // all such failures mean we skip this receiver
1288 Slog.w(TAG, "Exception getting recipient info for "
1289 + info.activityInfo.packageName, e);
1290 }
1291 if (!isAvailable) {
1292 if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST,
1293 "Skipping delivery to " + info.activityInfo.packageName + " / "
1294 + info.activityInfo.applicationInfo.uid
1295 + " : package no longer available");
1296 skip = true;
1297 }
1298 }
1299
1300 // If permissions need a review before any of the app components can run, we drop
1301 // the broadcast and if the calling app is in the foreground and the broadcast is
1302 // explicit we launch the review UI passing it a pending intent to send the skipped
1303 // broadcast.
1304 if (mService.mPermissionReviewRequired && !skip) {
1305 if (!requestStartTargetPermissionsReviewIfNeededLocked(r,
1306 info.activityInfo.packageName, UserHandle.getUserId(
1307 info.activityInfo.applicationInfo.uid))) {
1308 skip = true;
1309 }
1310 }
1311
1312 // This is safe to do even if we are skipping the broadcast, and we need
1313 // this information now to evaluate whether it is going to be allowed to run.
1314 final int receiverUid = info.activityInfo.applicationInfo.uid;
1315 // If it's a singleton, it needs to be the same app or a special app
1316 if (r.callingUid != Process.SYSTEM_UID && isSingleton
1317 && mService.isValidSingletonCall(r.callingUid, receiverUid)) {
1318 info.activityInfo = mService.getActivityInfoForUser(info.activityInfo, 0);
1319 }
//上面都是一些权限校验，暂时不详述了（和deliverToRegisteredReceiverLocked一样，前面也要做一些权限检查）
1320 String targetProcess = info.activityInfo.processName;
1321 ProcessRecord app = mService.getProcessRecordLocked(targetProcess,
1322 info.activityInfo.applicationInfo.uid, false);
1323
// 这里也是权限的校验，但是这里比较重要，因为Android新版本的限制越来越多在此处判断
// getAppStartModeLocked中会根据idle白名单，tmp名单，targetSdkVersion，appops权限等一些列校验
// 随着Android版本变化，此处的校验也越来越严格
1324 if (!skip) {
1325 final int allowed = mService.getAppStartModeLocked(
1326 info.activityInfo.applicationInfo.uid, info.activityInfo.packageName,
1329 info.activityInfo.applicationInfo.targetSdkVersion, -1, true, false, false, r.callerPackage); //r.callerPackage // who sent this 发送广播的进程
1330 if (allowed != ActivityManager.APP_START_MODE_NORMAL) {
1331 // We won't allow this receiver to be launched if the app has been
1332 // completely disabled from launches, or it was not explicitly sent
1333 // to it and the app is in a state that should not receive it
1334 // (depending on how getAppStartModeLocked has determined that).
1335 if (allowed == ActivityManager.APP_START_MODE_DISABLED) {
1336 Slog.w(TAG, "Background execution disabled: receiving "
1337 + r.intent + " to "
1338 + component.flattenToShortString());
1339 skip = true;
// 在Android O上对后台app不允许接收广播的管控
1340 } else if (((r.intent.getFlags()&Intent.FLAG_RECEIVER_EXCLUDE_BACKGROUND) != 0)
/**
5808 * If set, the broadcast will never go to manifest receivers in background (cached
5809 * or not running) apps, regardless of whether that would be done by default. By
5810 * default they will receive broadcasts if the broadcast has specified an
5811 * explicit component or package name.
5812 * @hide
5813
5814 public static final int FLAG_RECEIVER_EXCLUDE_BACKGROUND = 0x00800000;
*/
1341 || (r.intent.getComponent() == null
1342 && r.intent.getPackage() == null
1343 && ((r.intent.getFlags()
1344 & Intent.FLAG_RECEIVER_INCLUDE_BACKGROUND) == 0)
/**
5796 * If set, the broadcast will always go to manifest receivers in background (cached
5797 * or not running) apps, regardless of whether that would be done by default. By
5798 * default they will only receive broadcasts if the broadcast has specified an
5799 * explicit component or package name.
5800 *
5801 * NOTE: dumpstate uses this flag numerically, so when its value is changed
5802 * the broadcast code there must also be changed to match.
5803 *
5804 * @hide
5805
5806 public static final int FLAG_RECEIVER_INCLUDE_BACKGROUND = 0x01000000;
*/
1345 && !isSignaturePerm(r.requiredPermissions))) {
1346 mService.addBackgroundCheckViolationLocked(r.intent.getAction(),
1347 component.getPackageName());
1348 Slog.w(TAG, "Background execution not allowed: receiving "
1349 + r.intent + " to "
1350 + component.flattenToShortString());
1351 skip = true;
1352 }
1353 }
1354 }
1355
1356 if (!skip && !Intent.ACTION_SHUTDOWN.equals(r.intent.getAction())
1357 && !mService.mUserController
1358 .isUserRunning(UserHandle.getUserId(info.activityInfo.applicationInfo.uid),
1359 0 /* flags */)) {
1360 skip = true;
1361 Slog.w(TAG,
1362 "Skipping delivery to " + info.activityInfo.packageName + " / "
1363 + info.activityInfo.applicationInfo.uid + " : user is not running"); //user is not running，且广播不输ACTION_SHUTDOWN的情况下，肯定要skip receiver
1364 }
1365
1366 if (skip) {
1367 if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST,
1368 "Skipping delivery of ordered [" + mQueueName + "] "
1369 + r + " for whatever reason");
1370 r.delivery[recIdx] = BroadcastRecord.DELIVERY_SKIPPED;
1371 r.receiver = null;
1372 r.curFilter = null;
1373 r.state = BroadcastRecord.IDLE;
1374 r.manifestSkipCount++;
//如果要跳过当前的receiver（skip = true），对BroadcastRecord做一些清理工作
1375 scheduleBroadcastsLocked(); //触发下一轮
1376 return;
1377 }
1378 r.manifestCount++;
1379
1380 r.delivery[recIdx] = BroadcastRecord.DELIVERY_DELIVERED;
1381 r.state = BroadcastRecord.APP_RECEIVE; //将BroadcastRecord的状态设为APP_RECEIVE
1382 r.curComponent = component;
1383 r.curReceiver = info.activityInfo;
1384 if (DEBUG_MU && r.callingUid > UserHandle.PER_USER_RANGE) {
1385 Slog.v(TAG_MU, "Updated broadcast record activity info for secondary user, "
1386 + info.activityInfo + ", callingUid = " + r.callingUid + ", uid = "
1387 + receiverUid);
1388 }
1389
1390 if (brOptions != null && brOptions.getTemporaryAppWhitelistDuration() > 0) {
1391 scheduleTempWhitelistLocked(receiverUid,
1392 brOptions.getTemporaryAppWhitelistDuration(), r);
1393 }
1394
1395 // Broadcast is being executed, its package can't be stopped.
1396 try {
// 因为广播在派发，设置package不能被stop
1397 AppGlobals.getPackageManager().setPackageStoppedState(
1398 r.curComponent.getPackageName(), false, UserHandle.getUserId(r.callingUid));
1399 } catch (RemoteException e) {
1400 } catch (IllegalArgumentException e) {
1401 Slog.w(TAG, "Failed trying to unstop package "
1402 + r.curComponent.getPackageName() + ": " + e);
1403 }
1404
1405 // Is this receiver's application already running?
1406 if (app != null && app.thread != null && !app.killed) {
// 此处判断这个receiver的进程是否存在，如果存在，那么在processCurBroadcastLocked派发
1407 try {
1408 app.addPackage(info.activityInfo.packageName,
1409 info.activityInfo.applicationInfo.versionCode, mService.mProcessStats);
1410 processCurBroadcastLocked(r, app, skipOomAdj);
1411 return;
1412 } catch (RemoteException e) {
1413 Slog.w(TAG, "Exception when sending broadcast to "
1414 + r.curComponent, e);
1415 } catch (RuntimeException e) {
1416 Slog.wtf(TAG, "Failed sending broadcast to "
1417 + r.curComponent + " with " + r.intent, e);
1418 // If some unexpected exception happened, just skip
1419 // this broadcast. At this point we are not in the call
1420 // from a client, so throwing an exception out from here
1421 // will crash the entire system instead of just whoever
1422 // sent the broadcast.
1423 logBroadcastReceiverDiscardLocked(r);
1424 finishReceiverLocked(r, r.resultCode, r.resultData,
1425 r.resultExtras, r.resultAbort, false); //主要是做一些清理工作
1426 scheduleBroadcastsLocked(); //主动触发处理下一个receiver或者BroadcastRecord的流程;processNextBroadcast
1427 // We need to reset the state if we failed to start the receiver.
1428 r.state = BroadcastRecord.IDLE;
1429 return;
1430 }
1431
1432 // If a dead object exception was thrown -- fall through to
1433 // restart the application.
1434 }
1435
1436 // Not running -- get it started, to be executed when the app comes up.
1437 if (DEBUG_BROADCAST) Slog.v(TAG_BROADCAST,
1438 "Need to start app ["
1439 + mQueueName + "] " + targetProcess + " for broadcast " + r);
1440
1446 // 如果进程不在，启动新的进程
1447 if ((r.curApp=mService.startProcessLocked(targetProcess,
1448 info.activityInfo.applicationInfo, true,
1449 r.intent.getFlags() | Intent.FLAG_FROM_BACKGROUND,
1450 "broadcast", r.curComponent,
1454 (r.intent.getFlags()&Intent.FLAG_RECEIVER_BOOT_UPGRADE) != 0, false, false,
1455 r.callerPackage)) == null) {
1457 // Ah, this recipient is unavailable. Finish it if necessary,
1458 // and mark the broadcast record as ready for the next.
1459 Slog.w(TAG, "Unable to launch app "
1460 + info.activityInfo.applicationInfo.packageName + "/"
1461 + receiverUid + " for broadcast "
1462 + r.intent + ": process is bad");
1463 logBroadcastReceiverDiscardLocked(r);
1464 finishReceiverLocked(r, r.resultCode, r.resultData,
1465 r.resultExtras, r.resultAbort, false);
1466 scheduleBroadcastsLocked();
1467 r.state = BroadcastRecord.IDLE;
1468 return;
1469 }
1470
1471 mPendingBroadcast = r; //将进程放到 mPendingBroadcast 中，记录待处理的广播;在进程启动之后，进程attach到system server的时候处理
1472 mPendingBroadcastRecvIndex = recIdx;
1473 }
1474
BroadcastQueue#deliverToRegisteredReceiverLocked(广播传递给动态注册的接收者)
530 private void deliverToRegisteredReceiverLocked(BroadcastRecord r,
531 BroadcastFilter filter, boolean ordered, int index) {
532 boolean skip = false;
//检查广播发送方是否有BroadcastReceiver指定的权限
533 if (filter.requiredPermission != null) {
534 int perm = mService.checkComponentPermission(filter.requiredPermission,
535 r.callingPid, r.callingUid, -1, true);
536 if (perm != PackageManager.PERMISSION_GRANTED) {
537 Slog.w(TAG, "Permission Denial: broadcasting "
538 + r.intent.toString()
539 + " from " + r.callerPackage + " (pid="
540 + r.callingPid + ", uid=" + r.callingUid + ")"
541 + " requires " + filter.requiredPermission
542 + " due to registered receiver " + filter);
543 skip = true;
544 } else {
545 final int opCode = AppOpsManager.permissionToOpCode(filter.requiredPermission);
546 if (opCode != AppOpsManager.OP_NONE
547 && mService.mAppOpsService.noteOperation(opCode, r.callingUid,
548 r.callerPackage) != AppOpsManager.MODE_ALLOWED) {
549 Slog.w(TAG, "Appop Denial: broadcasting "
550 + r.intent.toString()
551 + " from " + r.callerPackage + " (pid="
552 + r.callingPid + ", uid=" + r.callingUid + ")"
553 + " requires appop " + AppOpsManager.permissionToOp(
554 filter.requiredPermission)
555 + " due to registered receiver " + filter);
556 skip = true;
557 }
558 }
559 }
560 if (!skip && r.requiredPermissions != null && r.requiredPermissions.length > 0) {
561 for (int i = 0; i < r.requiredPermissions.length; i++) {
562 String requiredPermission = r.requiredPermissions[i];
563 int perm = mService.checkComponentPermission(requiredPermission,
564 filter.receiverList.pid, filter.receiverList.uid, -1, true);
565 if (perm != PackageManager.PERMISSION_GRANTED) {
566 Slog.w(TAG, "Permission Denial: receiving "
567 + r.intent.toString()
568 + " to " + filter.receiverList.app
569 + " (pid=" + filter.receiverList.pid
570 + ", uid=" + filter.receiverList.uid + ")"
571 + " requires " + requiredPermission
572 + " due to sender " + r.callerPackage
573 + " (uid " + r.callingUid + ")");
574 skip = true;
575 break;
576 }
577 int appOp = AppOpsManager.permissionToOpCode(requiredPermission);
578 if (appOp != AppOpsManager.OP_NONE && appOp != r.appOp
//检查BroadcastReceiver是否有Broadcast要求的权限
581 && mService.mAppOpsService.checkOperation(appOp,
582 filter.receiverList.uid, filter.packageName)
583 != AppOpsManager.MODE_ALLOWED) {
584 Slog.w(TAG, "Appop Denial: receiving "
585 + r.intent.toString()
586 + " to " + filter.receiverList.app
587 + " (pid=" + filter.receiverList.pid
588 + ", uid=" + filter.receiverList.uid + ")"
589 + " requires appop " + AppOpsManager.permissionToOp(
590 requiredPermission)
591 + " due to sender " + r.callerPackage
592 + " (uid " + r.callingUid + ")");
593 skip = true;
594 break;
595 }
596 }
597 }
598 if (!skip && (r.requiredPermissions == null || r.requiredPermissions.length == 0)) {
599 int perm = mService.checkComponentPermission(null,
600 filter.receiverList.pid, filter.receiverList.uid, -1, true);
601 if (perm != PackageManager.PERMISSION_GRANTED) {
602 Slog.w(TAG, "Permission Denial: security check failed when receiving "
603 + r.intent.toString()
604 + " to " + filter.receiverList.app
605 + " (pid=" + filter.receiverList.pid
606 + ", uid=" + filter.receiverList.uid + ")"
607 + " due to sender " + r.callerPackage
608 + " (uid " + r.callingUid + ")");
609 skip = true;
610 }
611 }
612 if (!skip && r.appOp != AppOpsManager.OP_NONE
613
614 && mService.mAppOpsService.noteOperation(r.appOp,
615 filter.receiverList.uid, filter.packageName)
619 != AppOpsManager.MODE_ALLOWED) {
620 Slog.w(TAG, "Appop Denial: receiving "
621 + r.intent.toString()
622 + " to " + filter.receiverList.app
623 + " (pid=" + filter.receiverList.pid
624 + ", uid=" + filter.receiverList.uid + ")"
625 + " requires appop " + AppOpsManager.opToName(r.appOp)
626 + " due to sender " + r.callerPackage
627 + " (uid " + r.callingUid + ")");
628 skip = true;
629 }
630
636
637 if (!mService.mIntentFirewall.checkBroadcast(r.intent, r.callingUid,
638 r.callingPid, r.resolvedType, filter.receiverList.uid)) {
639 skip = true;
640 }
641
642 if (!skip && (filter.receiverList.app == null || filter.receiverList.app.killed
643 || filter.receiverList.app.crashing)) {
644 Slog.w(TAG, "Skipping deliver [" + mQueueName + "] " + r
645 + " to " + filter.receiverList + ": process gone or crashing");
646 skip = true;
647 }
648
649 // Ensure that broadcasts are only sent to other Instant Apps if they are marked as
650 // visible to Instant Apps.
651 final boolean visibleToInstantApps =
652 (r.intent.getFlags() & Intent.FLAG_RECEIVER_VISIBLE_TO_INSTANT_APPS) != 0;
653
654 if (!skip && !visibleToInstantApps && filter.instantApp
655 && filter.receiverList.uid != r.callingUid) {
656 Slog.w(TAG, "Instant App Denial: receiving "
657 + r.intent.toString()
658 + " to " + filter.receiverList.app
659 + " (pid=" + filter.receiverList.pid
660 + ", uid=" + filter.receiverList.uid + ")"
661 + " due to sender " + r.callerPackage
662 + " (uid " + r.callingUid + ")"
663 + " not specifying FLAG_RECEIVER_VISIBLE_TO_INSTANT_APPS");
664 skip = true;
665 }
666
667 if (!skip && !filter.visibleToInstantApp && r.callerInstantApp
668 && filter.receiverList.uid != r.callingUid) {
669 Slog.w(TAG, "Instant App Denial: receiving "
670 + r.intent.toString()
671 + " to " + filter.receiverList.app
672 + " (pid=" + filter.receiverList.pid
673 + ", uid=" + filter.receiverList.uid + ")"
674 + " requires receiver be visible to instant apps"
675 + " due to sender " + r.callerPackage
676 + " (uid " + r.callingUid + ")");
677 skip = true;
678 }
679
680 if (skip) {
//不满足发送条件的话，标记一下，结束发送
681 r.delivery[index] = BroadcastRecord.DELIVERY_SKIPPED;
682 return;
683 }
684
685 // If permissions need a review before any of the app components can run, we drop
686 // the broadcast and if the calling app is in the foreground and the broadcast is
687 // explicit we launch the review UI passing it a pending intent to send the skipped
688 // broadcast.
//特殊情况，还需要再次检查权限，中断广播发送
//再次满足发送条件后，会重新进入到后续的发送流程
689 if (mService.mPermissionReviewRequired) {
690 if (!requestStartTargetPermissionsReviewIfNeededLocked(r, filter.packageName,
691 filter.owningUserId)) {
692 r.delivery[index] = BroadcastRecord.DELIVERY_SKIPPED;
693 return;
694 }
695 }
696
697 r.delivery[index] = BroadcastRecord.DELIVERY_DELIVERED;//可以发送了，标记一下
698
699 // If this is not being sent as an ordered broadcast, then we
700 // don't want to touch the fields that keep track of the current
701 // state of ordered broadcasts.
702 if (ordered) { //针对串行广播，保存BroadRecord,BroadcastFilter中的结构，代表串行广播走到哪了
703 r.receiver = filter.receiverList.receiver.asBinder();
704 r.curFilter = filter;
705 filter.receiverList.curBroadcast = r;
706 r.state = BroadcastRecord.CALL_IN_RECEIVE; //当前Broadcast的状态
707 if (filter.receiverList.app != null) {
708 // Bump hosting application to no longer be in background
709 // scheduling class. Note that we can't do that if there
710 // isn't an app... but we can only be in that case for
711 // things that directly call the IActivityManager API, which
712 // are already core system stuff so don't matter for this.
713 r.curApp = filter.receiverList.app;
714 filter.receiverList.app.curReceivers.add(r);
715 mService.updateOomAdjLocked(r.curApp, true);
716 }
717 }
723 try {
724 if (DEBUG_BROADCAST_LIGHT) Slog.i(TAG_BROADCAST,
725 "Delivering to " + filter + " : " + r);
726 if (filter.receiverList.app != null && filter.receiverList.app.inFullBackup) {
//若BroadcastReceiver对应的进程处于fullBackup状态（备份和恢复），则不发送广播
727 // Skip delivery if full backup in progress
728 // If it's an ordered broadcast, we need to continue to the next receiver.
729 if (ordered) {
//有序广播必须处理完一个，才能处理下一个，因此这里主动触发一下
730 skipReceiverLocked(r);
731 }
732 } else {
//执行发送工作
733 performReceiveLocked(filter.receiverList.app, filter.receiverList.receiver,
734 new Intent(r.intent), r.resultCode, r.resultData,
735 r.resultExtras, r.ordered, r.initialSticky, r.userId);
736 }
737 if (ordered) {
738 r.state = BroadcastRecord.CALL_DONE_RECEIVE; //将BroadcastRecord的state设为CALL_DONE_RECEIVE
//从字面上理解，似乎取已经通过performReceiveLocked来调用BroadcastRecord实例中的onReceive了
739 }
740 } catch (RemoteException e) {
741 Slog.w(TAG, "Failure sending broadcast " + r.intent, e);
742 if (ordered) {
743 r.receiver = null;
744 r.curFilter = null;
745 filter.receiverList.curBroadcast = null;
746 if (filter.receiverList.app != null) {
747 filter.receiverList.app.curReceivers.remove(r);
748 }
749 }
750 }
751 }
总结上面的逻辑而言，大体分为以下4步:
1.处理并行队列中所有的并行广播；
2.处理等待中的mPendingBroadcast，正常情况下这个值为null，进程启动后attach到system_server就会处理；
大致处理逻辑如下:
attachApplicationLocked->sendPendingBroadcastsLocked-> processCurBroadcastLocked
322 public boolean sendPendingBroadcastsLocked(ProcessRecord app) {
323 boolean didSomething = false;
324 final BroadcastRecord br = mPendingBroadcast;
325 if (br != null && br.curApp.pid > 0 && br.curApp.pid == app.pid) {
326 if (br.curApp != app) {
327 Slog.e(TAG, "App mismatch when sending pending broadcast to "
328 + app.processName + ", intended target is " + br.curApp.processName);
329 return false;
330 }
331 try {
332 mPendingBroadcast = null;
333 processCurBroadcastLocked(br, app, false);
334 didSomething = true;
335 } catch (Exception e) {
336 Slog.w(TAG, "Exception in new application when starting receiver "
337 + br.curComponent.flattenToShortString(), e);
338 logBroadcastReceiverDiscardLocked(br);
339 finishReceiverLocked(br, br.resultCode, br.resultData,
340 br.resultExtras, br.resultAbort, false);
341 scheduleBroadcastsLocked();
342 // We need to reset the state if we failed to start the receiver.
343 br.state = BroadcastRecord.IDLE;
344 throw new RuntimeException(e.getMessage());
345 }
346 }
347 return didSomething;
348 }
3.对于串行广播，找到当前串行队列队头的BroadcastRecord;对Broadcast是否已经传递结束或者超时；这种情况下处理BroadcastRecord指定的resultTo，再将该广播从串行队列中移除；
4.找到串行广播本次要处理的receiver；区分是动态注册的还是静态注册的；
send Broadcast.png
