base: add reinit functionality to 'Env'

The 'reinit' and 'reinit_main_thread' methods are needed to implement
fork in Noux. Until now, they were provided by the 'Deprecated_env'
only.

repos/base/include/base/env.h

@@ -145,6 +145,33 @@ struct Genode::Env
 	 * executes this function before constructing libc components.
 	 */
 	virtual void exec_static_constructors() = 0;
+
+	/**
+	 * Reload parent capability and reinitialize environment resources
+	 *
+	 * This method is solely used for implementing fork in Noux. After forking
+	 * a process, the new child process is executed within a copy of the
+	 * address space of the forking process. Thereby, the new process inherits
+	 * the original 'env' object of the forking process, which is meaningless
+	 * in the context of the new process. By calling this function, the new
+	 * process is able to reinitialize its 'env' with meaningful capabilities
+	 * obtained via its updated parent capability.
+	 *
+	 * \noapi
+	 */
+	virtual void reinit(Native_capability::Raw) = 0;
+
+	/**
+	 * Reinitialize main-thread object
+	 *
+	 * \param stack_area_rm  new region map of the stack area
+	 *
+	 * This function is solely used for implementing fork as provided by the
+	 * Noux environment.
+	 *
+	 * \noapi
+	 */
+	virtual void reinit_main_thread(Capability<Region_map> &stack_area_rm) = 0;
 };
 
 #endif /* _INCLUDE__BASE__ENV_H_ */

repos/base/src/lib/base/component.cc

@@ -99,6 +99,16 @@ namespace {
 			return Genode::env_session_id_space();
 		}
 
+		void reinit(Native_capability::Raw raw) override
+		{
+			Genode::env_deprecated()->reinit(raw);
+		}
+
+		void reinit_main_thread(Capability<Region_map> &stack_area_rm) override
+		{
+			Genode::env_deprecated()->reinit_main_thread(stack_area_rm);
+		}
+
 		void _block_for_session()
 		{
 			/*

repos/libports/src/app/qt5/qt_launchpad/main.cpp

@@ -56,6 +56,14 @@ struct Qt_launchpad_namespace::Local_env : Genode::Env
 	void close(Parent::Client::Id id) { return genode_env.close(id); }
 
 	void exec_static_constructors() override { }
+
+	void reinit(Native_capability::Raw raw) override {
+		genode_env.reinit(raw);
+	}
+
+	void reinit_main_thread(Capability<Region_map> &stack_area_rm) override {
+		genode_env.reinit_main_thread(stack_area_rm);
+	}
 };
 
 

repos/libports/src/lib/libc/task.cc

@@ -161,6 +161,12 @@ class Libc::Env_implementation : public Libc::Env
 
 		/* already done by the libc */
 		void exec_static_constructors() override { }
+
+		void reinit(Native_capability::Raw raw) override {
+			_env.reinit(raw); }
+
+		void reinit_main_thread(Capability<Region_map> &stack_area_rm) override {
+			_env.reinit_main_thread(stack_area_rm); }
 };