Code snippets for Genode development.

a-genode-develop.md

• heap-alloc.cpp: allocate memory from env's heap.
• create-thread-deprecated.cpp: create deprecated thread.
• transfer-mem.cpp: transfer memory between two entrypoint.

create-thread-deprecated.cpp

class Worker : Genode::Thread_deprecated<4096> { // the type argument is stack size, in bytes.
   private:
    void entry() {
        Genode::log("entry of worker");
        while (1) {
        }
    }

   public:
    Handler() : Thread_deprecated("worker") { start(); }

    ~Handler() { Genode::log("destroy of worker"); }
};

void Component::construct(Genode::Env &env) {
    Timer::Connection main_timer;

    Handler *handler = new (Genode::env()->heap()) Handler();
    main_timer.msleep(200); // set time duration to let the new thread run.

    // other work.
  
    destroy(Genode::env()->heap(), handler); // destory thread.

    Genode::log("test create-thread-deprecated completed");
}

heap-alloc.cpp

/**
 * config:
    <start name="test-mingle-limit-mem">
		<resource name="RAM" quantum="10M"/>
	</start>
 */

void Component::construct(Genode::Env &env) {
    int bound = 1 << 22;
    Genode::log("before alloc consumed: ", Genode::env()->heap()->consumed());
    void *p = Genode::env()->heap()->alloc(bound);
    Genode::memset(p, 0x00, bound);
    Genode::printf("%p", p);
    Genode::log("after alloc consumed: ", Genode::env()->heap()->consumed());

    destroy(Genode::env()->heap(), handler);

    Genode::log("test alloc-mem completed");
}

transfer-mem.cpp

/**
 * transfer memory capability.
 */
void Component::construct(Genode::Env &env) {
    Genode::Ram_connection child_ram;
    child_ram.ref_account(env.ram_session_cap()); // add reference count to the source memory cap.
    Genode::log("child_ram available: ", child_ram.avail());
    env.ram().transfer_quota(child_ram.cap(), 1 << 20); // transfer the memory from source to target.
    Genode::log("child_ram available after transfer: ", child_ram.avail());

    Genode::log("test transfer-mem completed");
}