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老河口网站定制,关键词查网站,外贸网站制作设计,荣县住房和城乡建设厅网站系列文章 Android S从桌面点击图标启动APP流程 (一)Android S从桌面点击图标启动APP流程 (二) Android S从桌面点击图标启动APP流程 (三) Android S从桌面点击图标启动APP流程 (四) Android S从桌面点击图标启动APP流程 (五) Android 12的源码链接： android 1…

系列文章

Android S从桌面点击图标启动APP流程 (一)
Android S从桌面点击图标启动APP流程 (二)

Android S从桌面点击图标启动APP流程 (三)

Android S从桌面点击图标启动APP流程 (四)

Android S从桌面点击图标启动APP流程 (五)

Android 12的源码链接：

android 12 aosphttp://aospxref.com/android-12.0.0_r3/上文讲到了 Process.start, 这里接着往下讲解

ZygoteProcess#start

frameworks/base/core/java/android/os/ZygoteProcess.java

    public final Process.ProcessStartResult start(@NonNull final String processClass,final String niceName,int uid, int gid, @Nullable int[] gids,int runtimeFlags, int mountExternal,int targetSdkVersion,@Nullable String seInfo,@NonNull String abi,@Nullable String instructionSet,@Nullable String appDataDir,@Nullable String invokeWith,@Nullable String packageName,int zygotePolicyFlags,boolean isTopApp,@Nullable long[] disabledCompatChanges,@Nullable Map<String, Pair<String, Long>>pkgDataInfoMap,@Nullable Map<String, Pair<String, Long>>allowlistedDataInfoList,boolean bindMountAppsData,boolean bindMountAppStorageDirs,@Nullable String[] zygoteArgs) {// TODO (chriswailes): Is there a better place to check this value?if (fetchUsapPoolEnabledPropWithMinInterval()) {informZygotesOfUsapPoolStatus();}try {return startViaZygote(processClass, niceName, uid, gid, gids,runtimeFlags, mountExternal, targetSdkVersion, seInfo,abi, instructionSet, appDataDir, invokeWith, /*startChildZygote=*/ false,packageName, zygotePolicyFlags, isTopApp, disabledCompatChanges,pkgDataInfoMap, allowlistedDataInfoList, bindMountAppsData,bindMountAppStorageDirs, zygoteArgs);} catch (ZygoteStartFailedEx ex) {Log.e(LOG_TAG,"Starting VM process through Zygote failed");throw new RuntimeException("Starting VM process through Zygote failed", ex);}}

ZygoteProcess#startViaZygote

该过程主要工作是生成argsForZygote数组

frameworks/base/core/java/android/os/ZygoteProcess.java

    private Process.ProcessStartResult startViaZygote(@NonNull final String processClass,@Nullable final String niceName,final int uid, final int gid,@Nullable final int[] gids,int runtimeFlags, int mountExternal,int targetSdkVersion,@Nullable String seInfo,@NonNull String abi,@Nullable String instructionSet,@Nullable String appDataDir,@Nullable String invokeWith,boolean startChildZygote,@Nullable String packageName,int zygotePolicyFlags,boolean isTopApp,@Nullable long[] disabledCompatChanges,@Nullable Map<String, Pair<String, Long>>pkgDataInfoMap,@Nullable Map<String, Pair<String, Long>>allowlistedDataInfoList,boolean bindMountAppsData,boolean bindMountAppStorageDirs,@Nullable String[] extraArgs)throws ZygoteStartFailedEx {ArrayList<String> argsForZygote = new ArrayList<>();// --runtime-args, --setuid=, --setgid=,// and --setgroups= must go firstargsForZygote.add("--runtime-args");argsForZygote.add("--setuid=" + uid);argsForZygote.add("--setgid=" + gid);argsForZygote.add("--runtime-flags=" + runtimeFlags);if (mountExternal == Zygote.MOUNT_EXTERNAL_DEFAULT) {argsForZygote.add("--mount-external-default");} else if (mountExternal == Zygote.MOUNT_EXTERNAL_INSTALLER) {argsForZygote.add("--mount-external-installer");} else if (mountExternal == Zygote.MOUNT_EXTERNAL_PASS_THROUGH) {argsForZygote.add("--mount-external-pass-through");} else if (mountExternal == Zygote.MOUNT_EXTERNAL_ANDROID_WRITABLE) {argsForZygote.add("--mount-external-android-writable");}argsForZygote.add("--target-sdk-version=" + targetSdkVersion);// --setgroups is a comma-separated listif (gids != null && gids.length > 0) {final StringBuilder sb = new StringBuilder();sb.append("--setgroups=");final int sz = gids.length;for (int i = 0; i < sz; i++) {if (i != 0) {sb.append(',');}sb.append(gids[i]);}argsForZygote.add(sb.toString());}if (niceName != null) {argsForZygote.add("--nice-name=" + niceName);}if (seInfo != null) {argsForZygote.add("--seinfo=" + seInfo);}if (instructionSet != null) {argsForZygote.add("--instruction-set=" + instructionSet);}if (appDataDir != null) {argsForZygote.add("--app-data-dir=" + appDataDir);}if (invokeWith != null) {argsForZygote.add("--invoke-with");argsForZygote.add(invokeWith);}if (startChildZygote) {argsForZygote.add("--start-child-zygote");}if (packageName != null) {argsForZygote.add("--package-name=" + packageName);}if (isTopApp) {argsForZygote.add(Zygote.START_AS_TOP_APP_ARG);}
......argsForZygote.add(processClass);if (extraArgs != null) {Collections.addAll(argsForZygote, extraArgs);}synchronized(mLock) {// The USAP pool can not be used if the application will not use the systems graphics// driver.  If that driver is requested use the Zygote application start path.
根据当前的abi来选择与zygote还是zygote64来进行通信。return zygoteSendArgsAndGetResult(openZygoteSocketIfNeeded(abi),zygotePolicyFlags,argsForZygote);}}

ZygoteProcess#zygoteSendArgsAndGetResult

这个方法的主要功能是通过socket通道向Zygote进程发送一个参数列表，然后进入阻塞等待状态，直到远端的socket服务端发送回来新创建的进程pid才返回。

frameworks/base/core/java/android/os/ZygoteProcess.java

    private Process.ProcessStartResult zygoteSendArgsAndGetResult(ZygoteState zygoteState, int zygotePolicyFlags, @NonNull ArrayList<String> args)throws ZygoteStartFailedEx {// Throw early if any of the arguments are malformed. This means we can// avoid writing a partial response to the zygote.for (String arg : args) {// Making two indexOf calls here is faster than running a manually fused loop due// to the fact that indexOf is an optimized intrinsic.if (arg.indexOf('\n') >= 0) {throw new ZygoteStartFailedEx("Embedded newlines not allowed");} else if (arg.indexOf('\r') >= 0) {throw new ZygoteStartFailedEx("Embedded carriage returns not allowed");}}/** See com.android.internal.os.ZygoteArguments.parseArgs()* Presently the wire format to the zygote process is:* a) a count of arguments (argc, in essence)* b) a number of newline-separated argument strings equal to count** After the zygote process reads these it will write the pid of* the child or -1 on failure, followed by boolean to* indicate whether a wrapper process was used.*/String msgStr = args.size() + "\n" + String.join("\n", args) + "\n";if (shouldAttemptUsapLaunch(zygotePolicyFlags, args)) {try {return attemptUsapSendArgsAndGetResult(zygoteState, msgStr);} catch (IOException ex) {// If there was an IOException using the USAP pool we will log the error and// attempt to start the process through the Zygote.Log.e(LOG_TAG, "IO Exception while communicating with USAP pool - "+ ex.getMessage());}}return attemptZygoteSendArgsAndGetResult(zygoteState, msgStr);}

ZygoteProcess#attemptZygoteSendArgsAndGetResult

frameworks/base/core/java/android/os/ZygoteProcess.java

    private Process.ProcessStartResult attemptZygoteSendArgsAndGetResult(ZygoteState zygoteState, String msgStr) throws ZygoteStartFailedEx {try {final BufferedWriter zygoteWriter = zygoteState.mZygoteOutputWriter;final DataInputStream zygoteInputStream = zygoteState.mZygoteInputStream;zygoteWriter.write(msgStr);zygoteWriter.flush();// Always read the entire result from the input stream to avoid leaving// bytes in the stream for future process starts to accidentally stumble// upon.Process.ProcessStartResult result = new Process.ProcessStartResult();
等待socket服务端-zygote返回新创建的进程pid;result.pid = zygoteInputStream.readInt();result.usingWrapper = zygoteInputStream.readBoolean();if (result.pid < 0) {throw new ZygoteStartFailedEx("fork() failed");}return result;} catch (IOException ex) {zygoteState.close();Log.e(LOG_TAG, "IO Exception while communicating with Zygote - "+ ex.toString());throw new ZygoteStartFailedEx(ex);}}

system_server进程通过调用attemptZygoteSendArgsAndGetResult()方法通过socket方式向Zygote进程发送消息，这样会唤醒Zygote进程，来响应socket客户端的请求（即system_server端），接下来的操作便是在Zygote来创建进程