简介
文章内容为学习“千里马”课程整理的课程笔记；android源码基于android8.1.0版本，本文介绍bootanimation的启动和结束流程；
涉及到的源码路径
framework/base/cmds/bootanimation/*
framework/native/services/surfaceflinger/*
system/core/init/*
启动流程
int main(int, char**) {
startHidlServices();
...
// instantiate surfaceflinger
sp<SurfaceFlinger> flinger = new SurfaceFlinger();
setpriority(PRIO_PROCESS, 0, PRIORITY_URGENT_DISPLAY);
...
// initialize before clients can connect
flinger->init();
...
// run surface flinger in this thread
flinger->run();
return 0;
}
// Do not call property_set on main thread which will be blocked by init
// Use StartPropertySetThread instead.
void SurfaceFlinger::init() {
...
// Inform native graphics APIs whether the present timestamp is supported:
if (getHwComposer().hasCapability(
HWC2::Capability::PresentFenceIsNotReliable)) {
mStartPropertySetThread = new StartPropertySetThread(false);
} else {
mStartPropertySetThread = new StartPropertySetThread(true);
}
if (mStartPropertySetThread->Start() != NO_ERROR) {
ALOGE("Run StartPropertySetThread failed!");
}
ALOGV("Done initializing");
}
//设置开机动画是否退出的属性
bool StartPropertySetThread::threadLoop() {
// Set property service.sf.present_timestamp, consumer need check its readiness
property_set(kTimestampProperty, mTimestampPropertyValue ? "1" : "0");
// Clear BootAnimation exit flag
property_set("service.bootanim.exit", "0");
// Start BootAnimation if not started
property_set("ctl.start", "bootanim");
// Exit immediately
return false;
}
//init.cpp
int main(int argc, char** argv) {
...
signal_handler_init();
property_load_boot_defaults();
export_oem_lock_status();
//启动socket监听属性变化的服务端
start_property_service();
set_usb_controller();
...
return 0;
}
//创建一个socket服务
void start_property_service() {
property_set("ro.property_service.version", "2");
property_set_fd = CreateSocket(PROP_SERVICE_NAME, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
false, 0666, 0, 0, nullptr, sehandle);
if (property_set_fd == -1) {
PLOG(ERROR) << "start_property_service socket creation failed";
exit(1);
}
listen(property_set_fd, 8);
register_epoll_handler(property_set_fd, handle_property_set_fd);
}
//回调中处理监听收到的数据
static void handle_property_set_fd() {
static constexpr uint32_t kDefaultSocketTimeout = 2000; /* ms */
int s = accept4(property_set_fd, nullptr, nullptr, SOCK_CLOEXEC);
if (s == -1) {
return;
}
struct ucred cr;
socklen_t cr_size = sizeof(cr);
if (getsockopt(s, SOL_SOCKET, SO_PEERCRED, &cr, &cr_size) < 0) {
close(s);
PLOG(ERROR) << "sys_prop: unable to get SO_PEERCRED";
return;
}
SocketConnection socket(s, cr);
uint32_t timeout_ms = kDefaultSocketTimeout;
uint32_t cmd = 0;
if (!socket.RecvUint32(&cmd, &timeout_ms)) {
PLOG(ERROR) << "sys_prop: error while reading command from the socket";
socket.SendUint32(PROP_ERROR_READ_CMD);
return;
}
switch (cmd) {
case PROP_MSG_SETPROP: {
char prop_name[PROP_NAME_MAX];
char prop_value[PROP_VALUE_MAX];
if (!socket.RecvChars(prop_name, PROP_NAME_MAX, &timeout_ms) ||
!socket.RecvChars(prop_value, PROP_VALUE_MAX, &timeout_ms)) {
PLOG(ERROR) << "sys_prop(PROP_MSG_SETPROP): error while reading name/value from the socket";
return;
}
prop_name[PROP_NAME_MAX-1] = 0;
prop_value[PROP_VALUE_MAX-1] = 0;
handle_property_set(socket, prop_value, prop_value, true);
break;
}
case PROP_MSG_SETPROP2: {
std::string name;
std::string value;
if (!socket.RecvString(&name, &timeout_ms) ||
!socket.RecvString(&value, &timeout_ms)) {
PLOG(ERROR) << "sys_prop(PROP_MSG_SETPROP2): error while reading name/value from the socket";
socket.SendUint32(PROP_ERROR_READ_DATA);
return;
}
handle_property_set(socket, name, value, false);
break;
}
default:
LOG(ERROR) << "sys_prop: invalid command " << cmd;
socket.SendUint32(PROP_ERROR_INVALID_CMD);
break;
}
}
//property_service.cpp
//处理收到的消息内容
static void handle_property_set(SocketConnection& socket,
const std::string& name,
const std::string& value,
bool legacy_protocol) {
const char* cmd_name = legacy_protocol ? "PROP_MSG_SETPROP" : "PROP_MSG_SETPROP2";
if (!is_legal_property_name(name)) {
LOG(ERROR) << "sys_prop(" << cmd_name << "): illegal property name "" << name << """;
socket.SendUint32(PROP_ERROR_INVALID_NAME);
return;
}
struct ucred cr = socket.cred();
char* source_ctx = nullptr;
getpeercon(socket.socket(), &source_ctx);
if (android::base::StartsWith(name, "ctl.")) {
if (check_control_mac_perms(value.c_str(), source_ctx, &cr)) {
handle_control_message(name.c_str() + 4, value.c_str());
if (!legacy_protocol) {
socket.SendUint32(PROP_SUCCESS);
}
} else {
LOG(ERROR) << "sys_prop(" << cmd_name << "): Unable to " << (name.c_str() + 4)
<< " service ctl [" << value << "]"
<< " uid:" << cr.uid
<< " gid:" << cr.gid
<< " pid:" << cr.pid;
if (!legacy_protocol) {
socket.SendUint32(PROP_ERROR_HANDLE_CONTROL_MESSAGE);
}
}
} else {
if (check_mac_perms(name, source_ctx, &cr)) {
uint32_t result = property_set(name, value);
if (!legacy_protocol) {
socket.SendUint32(result);
}
} else {
LOG(ERROR) << "sys_prop(" << cmd_name << "): permission denied uid:" << cr.uid << " name:" << name;
if (!legacy_protocol) {
socket.SendUint32(PROP_ERROR_PERMISSION_DENIED);
}
}
}
freecon(source_ctx);
}
//启动服务，根据传过来bootanim的属性名启动bootanim的服务
void handle_control_message(const std::string& msg, const std::string& name) {
Service* svc = ServiceManager::GetInstance().FindServiceByName(name);
if (svc == nullptr) {
LOG(ERROR) << "no such service '" << name << "'";
return;
}
if (msg == "start") {
svc->Start();
} else if (msg == "stop") {
svc->Stop();
} else if (msg == "restart") {
svc->Restart();
} else {
LOG(ERROR) << "unknown control msg '" << msg << "'";
}
}
启动bootanimation.rc
service bootanim /system/bin/bootanimation
class core animation
user graphics
group graphics audio
disabled //加载bootanim服务但是不启动
oneshot
writepid /dev/stune/top-app/tasks
问题
- init进程如何拉起surfaceFlinger进程的？ juejin.cn/post/756579…
- surfaceFlinger如何拉起bootanimation进程的？
- native构建的app存放在out/garget/product/generic_x86_64/bin/目录下；
