Dynamically creating IPC channels for C++ development

Dynamic creation of an IPC channel on the client side includes the following steps:

1. Include the generated description header file (*.edl.cpp.h) in the client program.
2. Include the generated header files of the descriptions of the utilized interfaces (*.idl.cpp.h).
3. Include the header files:
   • /opt/KasperskyOS-Community-Edition-<version>/sysroot-*-kos/include/kosipc/application.h
   • /opt/KasperskyOS-Community-Edition-<version>/sysroot-*-kos/include/kosipc/make_application.h
   • /opt/KasperskyOS-Community-Edition-<version>/sysroot-*-kos/include/kosipc/connect_dynamic_channel.h
4. Get the pointers to the server name and the qualified name of the endpoint by using a name server, which is a special kernel service provided by the NameServer program. To do so, you must connect to the name server by calling the NsCreate() function and find the server that provides the required endpoint by using the NsEnumServices() function. For more details, refer to Dynamically creating IPC channels (cm_api.h, ns_api.h).
5. Create an application object by calling the kosipc::MakeApplicationAutodetect() function. (You can also use the kosipc::MakeApplication() and kosipc::MakeApplicationPureClient() functions.)
6. Create a proxy object for the required endpoint by calling the MakeProxy() function. Use the kosipc::ConnectDynamicChannel() function call as the input parameter of the MakeProxy() function. Pass the pointers for the server name and qualified name of the endpoint obtained at step 4 to the kosipc::ConnectDynamicChannel() function.

After successful initialization of the proxy object, the client can call methods of the required endpoint.

Example

NsHandle ns;

// Connect to a name server

Retcode rc = NsCreate(RTL_NULL, INFINITE_TIMEOUT, &ns);

char serverName[kl_core_Types_UCoreStringSize];

char endpointName[kl_core_Types_UCoreStringSize];

// Get pointers to the server name and qualified name of the endpoint

rc = NsEnumServices(

ns, interfaceName, 0,

serverName, kl_core_Types_UCoreStringSize,

endpointName, kl_core_Types_UCoreStringSize);

// Create and initialize the application object

kosipc::Application app = kosipc::MakeApplicationAutodetect();

// Create and initialize the proxy object

auto proxy = app.MakeProxy<IDLInterface>(

kosipc::ConnectDynamicChannel(serverName, endpointName))

// Call the method of the required endpoint

proxy->DoSomeWork();

Dynamic creation of an IPC channel on the server side includes the following steps:

1. Include the generated header file (*.edl.cpp.h) containing a description of the component structure of the server, including all provided endpoints, in the server program.
2. Include the header files:
   • /opt/KasperskyOS-Community-Edition-<version>/sysroot-*-kos/include/kosipc/application.h
   • /opt/KasperskyOS-Community-Edition-<version>/sysroot-*-kos/include/kosipc/event_loop.h
   • /opt/KasperskyOS-Community-Edition-<version>/sysroot-*-kos/include/kosipc/make_application.h
   • /opt/KasperskyOS-Community-Edition-<version>/sysroot-*-kos/include/kosipc/root_component.h
   • /opt/KasperskyOS-Community-Edition-<version>/sysroot-*-kos/include/kosipc/serve_dynamic_channel.h
   • /opt/KasperskyOS-Community-Edition-<version>/sysroot-*-kos/include/kosipc/simple_connection_acceptor.h
3. Create classes containing the implementations of interfaces that the server provides as endpoints. Create and initialize the objects of these classes.
4. Create an application object by calling the kosipc::MakeApplicationAutodetect() function.
5. Create and initialize the kosipc::components::Root class object that describes the structure of components and endpoints of the server. This structure is generated from the descriptions in the CDL and EDL files.
6. Bind the kosipc::components::Root class object to the class objects created at step 3.
7. Create and initialize the kosipc::EventLoop class object that implements a loop for dispatching incoming IPC messages by calling the MakeEventLoop() function. Use the ServeDynamicChannel() function call as an input parameter of the MakeEventLoop() function. Pass the kosipc::components::Root class object created at step 5 to the ServeDynamicChannel() function.
8. Start the loop for dispatching incoming IPC messages in a separate thread by calling the Run() method of the kosipc::EventLoop object.
9. Create and initialize the object that implements the handler for receiving incoming requests to dynamically create an IPC channel.

   When creating an object, you can use the kosipc::SimpleConnectionAcceptor class, which is the standard implementation of the kosipc::IConnectionAcceptor interface. (The kosipc::IConnectionAcceptor interface is defined in the file named /opt/KasperskyOS-Community-Edition-<version>/sysroot-*-kos/include/kosipc/connection_acceptor.h.) In this case, the handler will implement the following logic: if the endpoint requested by the client was published on the server, the request from the client will be accepted. Otherwise, it will be rejected.

   If you need to create your own handler, you should implement your own request handling logic in the OnConnectionRequest() method inherited from the kosipc::IConnectionAcceptor interface. This method will be called by the server when it receives a request for dynamic IPC channel creation from the client.

10. Create a kosipc::EventLoop class object that implements a loop for receiving incoming requests to dynamically create an IPC channel by calling the MakeEventLoop() function. Use the ServeConnectionRequests() function call as an input parameter of the MakeEventLoop() function. Pass the object created at step 9 to the ServeConnectionRequests() function.

    There can only be one loop for receiving incoming requests to dynamically create an IPC channel. The loop must work in one thread. The loop for receiving incoming requests to dynamically create an IPC channel must be created after the loop for dispatching incoming IPC channels is created (see step 7).

11. Start the loop for receiving incoming requests for a dynamic connection in the current thread by calling the Run() method of the kosipc::EventLoop object.

Example

// Create class objects that implement interfaces

// provided by the server as endpoints

MyIDLInterfaceImp_1 impl_1;

MyIDLInterfaceImp_2 impl_2;

// Create and initialize the application object

kosipc::Application app = kosipc::MakeApplicationAutodetect();

// Create and initialize the root object that describes

// the components and endpoints of the server

kosipc::components::Root root;

// Bind the root object to the class objects that implement the server endpoints.

// The fields of the root object repeat the description of components and endpoints

// defined collectively by the CDL and EDL files.

root.component1.endpoint1 = &impl_1;

root.component2.endpoint2 = &impl_2;

// Create and initialize the object that implements the

// loop for dispatching incoming IPC messages

kosipc::EventLoop loopDynamicChannel = app.MakeEventLoop(ServeDynamicChannel(root));

// Start the loop for dispatching incoming IPC messages in a separate thread

std::thread dynChannelThread(

[&loopDynamicChannel]() {

loopDynamicChannel.Run();

}

);

// Create an object that implements a standard handler for receiving incoming requests

// to dynamically create an IPC channel

kosipc::SimpleConnectionAcceptor acceptor(root);

// Create an object that implements a loop for receiving incoming requests

// to dynamically create an IPC channel

kosipc::EventLoop loopDynamicChannel = app.MakeEventLoop(ServeConnectionRequests(&acceptor));

// Start the loop for receiving incoming requests to dynamically create an IPC channel in the current thread

loopConnectionReq.Run();

If necessary, you can create and initialize multiple kosipc::components::Root class objects combined into a list of objects of the ServiceList type using the AddServices() method. For example, use of multiple objects enables you to separate components and endpoints of the server into groups or publish endpoints under different names.

Example

// Create and initialize the group_1 object

kosipc::components::Root group_1;

group_1.component1.endpoint1 = &impl_1;

group_1.component2.endpoint2 = &impl_2;

// Create and initialize the group_2 object

kosipc::components::Root group_2;

group_2.component1.endpoint1 = &impl_3;

group_2.component2.endpoint2 = &impl_4;

// Create and initialize the group_3 object

kosipc::components::Root group_3;

group_3.component1.endoint1 = &impl_5;

// Create a list of objects

ServiceList endpoints;

endpoints.AddServices(group_1);

endpoints.AddServices(group_2);

endpoints.AddServices(group_3.component1.endpoint1, "SomeCustomEndpointName");

// Create an object that implements the handler for receiving incoming requests

// to dynamically create an IPC channel

kosipc::SimpleConnectionAcceptor acceptor(std::move(endpoints));

// Create an object that implements a loop for receiving incoming requests

// to dynamically create an IPC channel

kosipc::EventLoop loopDynamicChannel = app.MakeEventLoop(ServeConnectionRequests(&acceptor));