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Commit b82b8f84 authored by Steven Moreland's avatar Steven Moreland
Browse files

ServiceManager: add isDeclared 

Most of the time, AIDL services exist in client/service pairs. In this
context, `while(true) getService` or `waitForService` makes sense.
However, for VINTF services, this client/server coupling isn't
guaranteed. A device may or may not have specific hardware. So, now
IServiceManager can tell a client when a server will exist so it will
know if it needs to wait for this service during boot-up. The function
waitForDeclaredService is provided for this.

These functions are generic (not referring to VINTF specifically)
because they may be expanded to include information about APEX services
in the future OR the infrastructure may be made generic to work, if
desired, on system services.

Bug: 141828236
Test: binderStabilityTest, using waitForDeclaredService function
Change-Id: Ia230625e44e1685cc3fa9230ece8f0a25c88585e
parent 1aed8b36

cmds/dumpsys/tests/dumpsys_test.cpp

+1 −0
Original line number Diff line number Diff line
@@ -54,6 +54,7 @@ class ServiceManagerMock : public IServiceManager { 
    MOCK_METHOD4(addService, status_t(const String16&, const sp<IBinder>&, bool, int));

    MOCK_METHOD1(listServices, Vector<String16>(int));

    MOCK_METHOD1(waitForService, sp<IBinder>(const String16&));

    MOCK_METHOD1(isDeclared, bool(const String16&));

  protected:

    MOCK_METHOD0(onAsBinder, IBinder*());

};

cmds/servicemanager/ServiceManager.cpp

+24 −5
Original line number Diff line number Diff line
@@ -34,11 +34,7 @@ using ::android::internal::Stability; 
namespace android {



#ifndef VENDORSERVICEMANAGER

static bool meetsDeclarationRequirements(const sp<IBinder>& binder, const std::string& name) {

    if (!Stability::requiresVintfDeclaration(binder)) {

        return true;

    }



static bool isVintfDeclared(const std::string& name) {

    size_t firstSlash = name.find('/');

    size_t lastDot = name.rfind('.', firstSlash);

    if (firstSlash == std::string::npos || lastDot == std::string::npos) {
@@ -62,6 +58,14 @@ static bool meetsDeclarationRequirements(const sp<IBinder>& binder, const std::s 
               << " in the VINTF manifest.";

    return false;

}



static bool meetsDeclarationRequirements(const sp<IBinder>& binder, const std::string& name) {

    if (!Stability::requiresVintfDeclaration(binder)) {

        return true;

    }



    return isVintfDeclared(name);

}

#endif  // !VENDORSERVICEMANAGER



ServiceManager::ServiceManager(std::unique_ptr<Access>&& access) : mAccess(std::move(access)) {}
@@ -270,6 +274,21 @@ Status ServiceManager::unregisterForNotifications( 
    return Status::ok();

}



Status ServiceManager::isDeclared(const std::string& name, bool* outReturn) {

    auto ctx = mAccess->getCallingContext();



    if (!mAccess->canFind(ctx, name)) {

        return Status::fromExceptionCode(Status::EX_SECURITY);

    }



    *outReturn = false;



#ifndef VENDORSERVICEMANAGER

    *outReturn = isVintfDeclared(name);

#endif

    return Status::ok();

}



void ServiceManager::removeCallback(const wp<IBinder>& who,

                                    CallbackMap::iterator* it,

                                    bool* found) {

cmds/servicemanager/ServiceManager.h

+1 −0
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ public: 
                                            const sp<IServiceCallback>& callback) override;

    binder::Status unregisterForNotifications(const std::string& name,

                                              const sp<IServiceCallback>& callback) override;

    binder::Status isDeclared(const std::string& name, bool* outReturn) override;



    void binderDied(const wp<IBinder>& who) override;

libs/binder/IServiceManager.cpp

+9 −0
Original line number Diff line number Diff line
@@ -72,6 +72,7 @@ public: 
                        bool allowIsolated, int dumpsysPriority) override;

    Vector<String16> listServices(int dumpsysPriority) override;

    sp<IBinder> waitForService(const String16& name16) override;

    bool isDeclared(const String16& name) override;



    // for legacy ABI

    const String16& getInterfaceDescriptor() const override {
@@ -321,4 +322,12 @@ sp<IBinder> ServiceManagerShim::waitForService(const String16& name16) 
    }

}



bool ServiceManagerShim::isDeclared(const String16& name) {

    bool declared;

    if (!mTheRealServiceManager->isDeclared(String8(name).c_str(), &declared).isOk()) {

        return false;

    }

    return declared;

}



} // namespace android

libs/binder/aidl/android/os/IServiceManager.aidl

+7 −0
Original line number Diff line number Diff line
@@ -89,4 +89,11 @@ interface IServiceManager { 
     * Unregisters all requests for notifications for a specific callback.

     */

    void unregisterForNotifications(@utf8InCpp String name, IServiceCallback callback);



    /**

     * Returns whether a given interface is declared on the device, even if it

     * is not started yet. For instance, this could be a service declared in the VINTF

     * manifest.

     */

    boolean isDeclared(@utf8InCpp String name);

}