libc_noux: remove dependency on 'platform_env.h'

Currently, libc_noux includes the 'base/src/base/env/platform_env.h' file
to be able to reinitialize the environment using the 'Platform_env'
interface. For base-linux, a special version of this file exists and the
inclusion of the generic version in libc_noux causes GCC 4.9 to make wrong
assumptions about the memory layout of the 'Env' object returned by
'Genode::env()'.

This commit moves the reinitialization functions to the 'Env' interface to
avoid the need to include the 'platform_env.h' file in libc_noux.

Fixes #1510

repos/base-linux/src/base/env/platform_env.cc

@@ -154,10 +154,6 @@ Platform_env::Local_parent &Platform_env::_parent()
 }
 
 
-void Platform_env::reinit(Native_capability::Dst, long) { }
-void Platform_env::reinit_main_thread(Rm_session_capability &) { }
-
-
 Platform_env::Platform_env()
 :
 	Platform_env_base(static_cap_cast<Ram_session>(_parent().session("Env::ram_session", "")),

repos/base-linux/src/base/env/platform_env.h

@@ -353,6 +353,14 @@ namespace Genode {
 			Linux_cpu_session      *cpu_session()     { return &_cpu_session_client; }
 			Cpu_session_capability  cpu_session_cap() { return  _cpu_session_cap; }
 			Pd_session             *pd_session()      { return &_pd_session_client; }
+
+			/*
+			 * Support functions for implementing fork on Noux.
+			 *
+			 * Not supported on Linux.
+			 */
+			void reinit(Native_capability::Dst, long) { };
+			void reinit_main_thread(Rm_session_capability &) { };
 	};
 
 
@@ -431,16 +439,6 @@ namespace Genode {
 			 */
 			~Platform_env() { _parent().exit(0); }
 
-			/*
-			 * Support functions for implementing fork on Noux.
-			 *
-			 * Not supported on Linux.
-			 *
-			 * See the documentation in 'base/src/base/env/platform_env.h'
-			 */
-			void reinit(Native_capability::Dst, long);
-			void reinit_main_thread(Rm_session_capability &);
-
 
 			/*************************************
 			 ** Emergency_ram_reserve interface **

repos/base/include/base/env.h

@@ -16,6 +16,7 @@
 
 #include <parent/capability.h>
 #include <parent/parent.h>
+#include <rm_session/capability.h>
 #include <rm_session/rm_session.h>
 #include <ram_session/ram_session.h>
 #include <cpu_session/cpu_session.h>
@@ -84,6 +85,35 @@ struct Genode::Env
 	 * Heap backed by the RAM session of the environment
 	 */
 	virtual Allocator *heap() = 0;
+
+	/**
+	 * Reload parent capability and reinitialize environment resources
+	 *
+	 * This function is solely used for implementing fork semantics.
+	 * 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::Dst, long) = 0;
+
+	/**
+	 * Reinitialize main-thread object
+	 *
+	 * \param context_area_rm  new RM session of the context area
+	 *
+	 * This function is solely used for implementing fork semantics
+	 * as provided by the Noux environment.
+	 *
+	 * \noapi
+	 */
+	virtual void reinit_main_thread(Rm_session_capability &) = 0;
+
 };
 
 

repos/base/src/base/env/platform_env.h

@@ -114,28 +114,10 @@ class Genode::Platform_env : public Genode::Env, public Emergency_ram_reserve
 			_emergency_ram_ds(_resources.ram.alloc(_emergency_ram_size()))
 		{ }
 
-		/**
-		 * Reload parent capability and reinitialize environment resources
-		 *
-		 * This function is solely used for implementing fork semantics.
-		 * 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.
+		/*
+		 * Support functions for implementing fork on Noux.
 		 */
 		void reinit(Native_capability::Dst, long);
-
-		/**
-		 * Reinitialize main-thread object
-		 *
-		 * \param context_area_rm  new RM session of the context area
-		 *
-		 * This function is solely used for implementing fork semantics
-		 * as provided by the Noux environment.
-		 */
 		void reinit_main_thread(Rm_session_capability &);
 
 

repos/ports/lib/mk/libc_noux.mk

@@ -4,8 +4,6 @@ LIBS += libc
 
 REP_INC_DIR += src/lib/libc
 
-INC_DIR += $(BASE_DIR)/src/base/env/
-
 vpath %.cc $(REP_DIR)/src/lib/libc_noux
 
 SHARED_LIB = yes

repos/ports/src/lib/libc_noux/plugin.cc

@@ -20,7 +20,6 @@
 #include <rom_session/connection.h>
 #include <base/sleep.h>
 #include <dataspace/client.h>
-#include <platform_env.h>
 
 /* noux includes */
 #include <noux_session/connection.h>
@@ -505,8 +504,7 @@ extern "C" void fork_trampoline()
 {
 	/* reinitialize environment */
 	using namespace Genode;
-	Platform_env * const platform_env = dynamic_cast<Platform_env *>(env());
-	platform_env->reinit(new_parent.dst, new_parent.local_name);
+	env()->reinit(new_parent.dst, new_parent.local_name);
 
 	/* reinitialize standard-output connection */
 	stdout_reconnect();
@@ -520,7 +518,7 @@ extern "C" void fork_trampoline()
 
 	/* reinitialize main-thread object which implies reinit of context area */
 	auto context_area_rm = noux_connection()->context_area_rm_session();
-	platform_env->reinit_main_thread(context_area_rm);
+	env()->reinit_main_thread(context_area_rm);
 
 	/* apply processor state that the forker had when he did the fork */
 	longjmp(fork_jmp_buf, 1);