system/core/init/main.cpp
system/core/init/init.cpp
system/core/init/parser.cpp
system/core/init/epoll.h
system/core/init/epoll.cpp
system/core/rootdir/init.rc
system/core/rootdir/init.zygote64.rc
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int main(int argc, char** argv) { #if __has_feature(address_sanitizer) __asan_set_error_report_callback(AsanReportCallback); #endif setpriority(PRIO_PROCESS, 0, -20); #endif setpriority(PRIO_PROCESS, 0, -20) if (! strcmp(basename(argv[0]), "ueventd")) { return ueventd_main(argc, argv); } if (argc > 1) { if (! strcmp(argv[1], "subcontext")) { android::base::InitLogging(argv, &android::base::KernelLogger); const BuiltinFunctionMap function_map; // return SubcontextMain(argc, argv, &function_map); } if (! STRCMP (argv[1], "selinux_setup")) {return SetupSelinux(argv); } if (! STRCMP (argv[1], "second_stage") {return SecondStageMain(argc, argv); }} return FirstStageMain(argc, argv); }Copy the code

Int FirstStageMain(int argc, char** argv) {if (REBOOT_BOOTLOADER_ON_PANIC) {// Start bootloader when init process crashes, Let developers positioning problem InstallRebootSignalHandlers (); } boot_clock::time_point start_time = boot_clock::now(); std::vector<std::pair<std::string, int>> errors; #define CHECKCALL(x) \ if ((x) ! = 0) errors.emplace_back(#x " failed", errno); // Clear the umask. umask(0); CHECKCALL(clearenv())); . #undef CHECKCALL // redirect standard input/output error output to dev/null, SetStdioToDevNull(argv) for both the first and second phases; InitKernelLogging(argv) is not enabled for Android logs. // Load some ramdisk... // Selinux_setup const char* path = "/system/bin/init"; const char* args[] = {path, "selinux_setup", nullptr}; auto fd = open("/dev/kmsg", O_WRONLY | O_CLOEXEC); dup2(fd, STDOUT_FILENO); dup2(fd, STDERR_FILENO); close(fd); execv(path, const_cast<char**>(args)); return 1; }Copy the code

Int SetupSelinux(char** argv) {// Some selinux-related initializers... // Enter the second phase of the init process const char* path = "/system/bin/init"; const char* args[] = {path, "second_stage", nullptr}; execv(path, const_cast<char**>(args)); return 1; }Copy the code

Int SecondStageMain(int argc, char** argv) {if (REBOOT_BOOTLOADER_ON_PANIC) { Let developers positioning problem InstallRebootSignalHandlers (); } boot_clock::time_point start_time = boot_clock::now(); trigger_shutdown = [](const std::string& command) { shutdown_state.TriggerShutdown(command); }; Dev /null SetStdioToDevNull(argv); // As in the first step, redirect the standard input output error output to dev/null SetStdioToDevNull(argv); InitSecondStageLogging(argv); // There are some linux-related Settings, which are omitted here. // Initialize some properties PropertyInit(); //debug related if (load_debug_prop) {UmountDebugRamdisk(); } // mount filesystems MountExtraFilesystems(); / / set SELinux SelinuxSetupKernelLogging (); Selabel SelabelInitialize(); // Set Selinux and restore some context SelinuxRestoreContext(); // Create epoll epoll epoll; if (auto result = epoll.Open(); ! result.ok()) { PLOG(FATAL) << result.error(); } // Set InstallSignalFdHandler(&epoll); // Set the notification function for property changes InstallInitNotifier(&epoll); // Set the system property. StartPropertyService(&property_fd); // Make the time that init stages started available for bootstat to log. RecordStageBoottimes(start_time); // Set libavb if (const char* avb_version = getenv("INIT_AVB_VERSION"); avb_version ! = nullptr) { SetProperty("ro.boot.avb_version", avb_version); } unsetenv("INIT_AVB_VERSION"); fs_mgr_vendor_overlay_mount_all(); export_oem_lock_status(); MountHandler mount_handler(&epoll); SetUsbController(); const BuiltinFunctionMap& function_map = GetBuiltinFunctionMap(); Action::set_function_map(&function_map); if (! SetupMountNamespaces()) { PLOG(FATAL) << "SetupMountNamespaces failed"; } // Initialize the second-stage context InitializeSubcontext(); / / build ActionManager and ServiceList related objects, used to resolve the rc related documents of the action, service ActionManager & am = ActionManager: : GetInstance (); ServiceList& sm = ServiceList::GetInstance(); // Load the startup configuration file, that is, some rc files LoadBootScripts(am, sm); // Turning this on and letting the INFO logging be discarded adds 0.2s to // Nexus 9 boot time, so it's disabled by default. if (false) DumpState(); / / make sure gsi available auto is_running = android: : gsi: : IsGsiRunning ()? "1", "0"; SetProperty(gsi::kGsiBootedProp, is_running); auto is_installed = android::gsi::IsGsiInstalled() ? "1", "0"; SetProperty(gsi::kGsiInstalledProp, is_installed); QueueBuiltinAction(SetupCgroupsAction, "SetupCgroups"); am.QueueBuiltinAction(SetKptrRestrictAction, "SetKptrRestrict"); am.QueueBuiltinAction(TestPerfEventSelinuxAction, "TestPerfEventSelinux"); // Init has four stages: early-init, init, early-boot, boot // early-init am.QueueEventTrigger("early-init"); QueueBuiltinAction(wait_for_coldboot_done_action, "wait_for_coldboot_done"); / / need/dev action. Am QueueBuiltinAction (MixHwrngIntoLinuxRngAction, "MixHwrngIntoLinuxRng"); am.QueueBuiltinAction(SetMmapRndBitsAction, "SetMmapRndBits"); // Initialize the /dev/keychord device to debug the related Keychords Keychords; am.QueueBuiltinAction( [&epoll, &keychords](const BuiltinArguments& args) -> Result<void> { for (const auto& svc : ServiceList::GetInstance()) { keychords.Register(svc->keycodes()); } keychords.Start(&epoll, HandleKeychord); return {}; }, "KeychordInit"); // Phase 2, init phase am.queueEventTrigger ("init"); // If wait_for_coldboot_done is not ready, Just repeat. Mix_hwrng_into_linux_rng am QueueBuiltinAction (MixHwrngIntoLinuxRngAction, "MixHwrngIntoLinuxRng"); // Don't mount filesystems or start core system services in charger mode. std::string bootmode = GetProperty("ro.bootmode", ""); if (bootmode == "charger") { am.QueueEventTrigger("charger"); } else {// With filesystems in non-charger mode, start core system am.queueEventtrigger ("late-init"); QueueBuiltinAction(queue_property_triggerS_action, "queue_property_triggers"); // Restore priority setPriority (PRIO_PROCESS, 0, 0); While (true) {// This is an infinite loop, which is used to process events that have been added before. If the child dies, Will restart the corresponding child process auto epoll_timeout = STD: : optional < STD: : chrono: : milliseconds > {}; auto shutdown_command = shutdown_state.CheckShutdown(); if (shutdown_command) { LOG(INFO) << "Got shutdown_command '" << *shutdown_command << "' Calling HandlePowerctlMessage()"; HandlePowerctlMessage(*shutdown_command); shutdown_state.set_do_shutdown(false); } if (! (prop_waiter_state MightBeWaiting () | | Service: : is_exec_service_running ())) {/ / added to the action of the Command before implementation am.ExecuteOneCommand(); } if (! IsShuttingDown()) { auto next_process_action_time = HandleProcessActions(); // If the process needs to be restarted, Wakes the if (next_process_action_time) {epoll_timeout = STD: : chrono: : ceil < STD: : chrono: : milliseconds > ( *next_process_action_time - boot_clock::now()); if (*epoll_timeout < 0ms) epoll_timeout = 0ms; } } if (! (prop_waiter_state MightBeWaiting () | | Service: : is_exec_service_running ())) {/ / if didn't finish his work, If (am.hasmoreCommands ()) epoll_timeout = 0ms; } auto pending_functions = epoll.Wait(epoll_timeout); if (! pending_functions.ok()) { LOG(ERROR) << pending_functions.error(); } else if (! Pending_functions - > empty ()) {/ / before with other functions, to deal with children, avoid daemon see competition program exits and produce init ReapAnyOutstandingChildren (); For (const auto& function: *pending_functions) {(*function)(); } } if (! IsShuttingDown()) { HandleControlMessages(); SetUsbController(); } } return 0; }Copy the code

class Epoll {
  public:
    Epoll();

    Result<void> Open();
    Result<void> RegisterHandler(int fd, std::function<void()> handler, uint32_t events = EPOLLIN);
    Result<void> UnregisterHandler(int fd);
    Result<std::vector<std::function<void()>*>> Wait(
            std::optional<std::chrono::milliseconds> timeout);

  private:
    android::base::unique_fd epoll_fd_;
    std::map<int, std::function<void()>> epoll_handlers_;
};
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InstallSignalFdHandler(&epoll); // Set InstallSignalFdHandler(&epoll); // Set the notification function for property changes InstallInitNotifier(&epoll);Copy the code

static void InstallSignalFdHandler(Epoll* epoll) { ... // Register a handler to unblock signals in the child processes. const int result = pthread_atfork(nullptr, nullptr, &UnblockSignals); if (result ! = 0) { LOG(FATAL) << "Failed to register a fork handler: " << strerror(result); } signal_fd = signalfd(-1, &mask, SFD_CLOEXEC); if (signal_fd == -1) { PLOG(FATAL) << "failed to create signalfd"; If (auto result = epoll->RegisterHandler(signal_fd, HandleSignalFd); ! result.ok()) { LOG(FATAL) << result.error(); }}Copy the code

static void InstallInitNotifier(Epoll* epoll) {
    wake_main_thread_fd = eventfd(0, EFD_CLOEXEC);
    if (wake_main_thread_fd == -1) {
        PLOG(FATAL) << "Failed to create eventfd for waking init";
    }
    auto clear_eventfd = [] {
        uint64_t counter;
        TEMP_FAILURE_RETRY(read(wake_main_thread_fd, &counter, sizeof(counter)));
    };

    if (auto result = epoll->RegisterHandler(wake_main_thread_fd, clear_eventfd); !result.ok()) {
        LOG(FATAL) << result.error();
    }
}
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static void LoadBootScripts(ActionManager& action_manager, ServiceList& service_list) { Parser parser = CreateParser(action_manager, service_list); Bootscript = GetProperty("ro.boot.init_rc", ""); STD ::string bootscript = GetProperty("ro.boot.init_rc", ""); if (bootscript.empty()) { parser.ParseConfig("/system/etc/init/hw/init.rc"); if (! parser.ParseConfig("/system/etc/init")) { late_import_paths.emplace_back("/system/etc/init"); } // late_import is available only in Q and earlier release. As we don't // have system_ext in those versions, skip late_import for system_ext. parser.ParseConfig("/system_ext/etc/init"); if (! parser.ParseConfig("/product/etc/init")) { late_import_paths.emplace_back("/product/etc/init"); } if (! parser.ParseConfig("/odm/etc/init")) { late_import_paths.emplace_back("/odm/etc/init"); } if (! parser.ParseConfig("/vendor/etc/init")) { late_import_paths.emplace_back("/vendor/etc/init"); } } else { parser.ParseConfig(bootscript); Parser CreateParser(ActionManager& Action_manager, ServiceList& Service_list) {Parser Parser; parser.AddSectionParser("service", std::make_unique<ServiceParser>( &service_list, GetSubcontext(), std::nullopt)); parser.AddSectionParser("on", std::make_unique<ActionParser>(&action_manager, GetSubcontext())); parser.AddSectionParser("import", std::make_unique<ImportParser>(&parser)); return parser; }Copy the code

import /init.${ro.zygote}.rc
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service zygote /system/bin/app_process64 -Xzygote /system/bin --zygote --start-system-server
    class main
    priority -20
    user root
    group root readproc reserved_disk
    socket zygote stream 660 root system
    socket usap_pool_primary stream 660 root system
    onrestart write /sys/android_power/request_state wake
    onrestart write /sys/power/state on
    onrestart restart audioserver
    onrestart restart cameraserver
    onrestart restart media
    onrestart restart netd
    onrestart restart wificond
    writepid /dev/cpuset/foreground/tasks
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