Add support for updatable services
A service with 'updatable' option can be overriden by the same service
definition in APEXes.
/system/etc/init/foo.rc:
service foo /system/bin/foo
updatable
/apex/myapex/etc/init.rc:
service foo /apex/myapex/bin/foo
override
Overriding a non-updatable (i.e. without updatable option) service
from APEXes is prohibited.
When an updatable service is started before APEXes are all activated,
the execution is delayed until when the APEXes are all activated.
Bug: 117403679
Test: m apex.test; adb push <built_apex> /data/apex; adb reboot
adb shell, then lsof -p $(pidof surfaceflinger) shows that
the process is executing
/apex/com.android.example.apex@1/bin/surfaceflinger instead of
/system/bin/surfaceflinger
Change-Id: I8a57b8e7f6da81b4d2843e261a9a935dd279067c
diff --git a/init/service.cpp b/init/service.cpp
index 1bda7ec..5aa3764 100644
--- a/init/service.cpp
+++ b/init/service.cpp
@@ -765,6 +765,11 @@
return Success();
}
+Result<Success> Service::ParseUpdatable(std::vector<std::string>&& args) {
+ updatable_ = true;
+ return Success();
+}
+
class Service::OptionParserMap : public KeywordMap<OptionParser> {
public:
OptionParserMap() {}
@@ -817,6 +822,7 @@
{"socket", {3, 6, &Service::ParseSocket}},
{"timeout_period",
{1, 1, &Service::ParseTimeoutPeriod}},
+ {"updatable", {0, 0, &Service::ParseUpdatable}},
{"user", {1, 1, &Service::ParseUser}},
{"writepid", {1, kMax, &Service::ParseWritepid}},
};
@@ -834,6 +840,13 @@
}
Result<Success> Service::ExecStart() {
+ if (is_updatable() && !ServiceList::GetInstance().IsServicesUpdated()) {
+ // Don't delay the service for ExecStart() as the semantic is that
+ // the caller might depend on the side effect of the execution.
+ return Error() << "Cannot start an updatable service '" << name_
+ << "' before configs from APEXes are all loaded";
+ }
+
flags_ |= SVC_ONESHOT;
if (auto result = Start(); !result) {
@@ -851,6 +864,13 @@
}
Result<Success> Service::Start() {
+ if (is_updatable() && !ServiceList::GetInstance().IsServicesUpdated()) {
+ ServiceList::GetInstance().DelayService(*this);
+ return Error() << "Cannot start an updatable service '" << name_
+ << "' before configs from APEXes are all loaded. "
+ << "Queued for execution.";
+ }
+
bool disabled = (flags_ & (SVC_DISABLED | SVC_RESET));
// Starting a service removes it from the disabled or reset state and
// immediately takes it out of the restarting state if it was in there.
@@ -1280,6 +1300,32 @@
}
}
+void ServiceList::MarkServicesUpdate() {
+ services_update_finished_ = true;
+
+ // start the delayed services
+ for (const auto& name : delayed_service_names_) {
+ Service* service = FindService(name);
+ if (service == nullptr) {
+ LOG(ERROR) << "delayed service '" << name << "' could not be found.";
+ continue;
+ }
+ if (auto result = service->Start(); !result) {
+ LOG(ERROR) << result.error_string();
+ }
+ }
+ delayed_service_names_.clear();
+}
+
+void ServiceList::DelayService(const Service& service) {
+ if (services_update_finished_) {
+ LOG(ERROR) << "Cannot delay the start of service '" << service.name()
+ << "' because all services are already updated. Ignoring.";
+ return;
+ }
+ delayed_service_names_.emplace_back(service.name());
+}
+
Result<Success> ServiceParser::ParseSection(std::vector<std::string>&& args,
const std::string& filename, int line) {
if (args.size() < 3) {
@@ -1291,6 +1337,8 @@
return Error() << "invalid service name '" << name << "'";
}
+ filename_ = filename;
+
Subcontext* restart_action_subcontext = nullptr;
if (subcontexts_) {
for (auto& subcontext : *subcontexts_) {
@@ -1326,6 +1374,11 @@
<< "'";
}
+ if (StartsWith(filename_, "/apex/") && !old_service->is_updatable()) {
+ return Error() << "cannot update a non-updatable service '" << service_->name()
+ << "' with a config in APEX";
+ }
+
service_list_->RemoveService(*old_service);
old_service = nullptr;
}