loosend restriction imposed by #final. a kernel class can inherit from a final class.

added an experimental class _KernelProcess for process management

moo/kernel/Process.moo

@@ -77,6 +77,12 @@ class(#pointer,#final,#limited) Process(Object)
 	}
 }
 
+class(#pointer,#limited,#final) _KernelProcess(Process)
+{
+	// _KernelProcess is a predefined kernel class. so it can inherit from a final class, Process.
+	// It must be exactly the same as Process other than inheritance and is used internally only.
+}
+
 class Semaphore(Object)
 {
 	var waiting_head  := nil,

moo/kernel/System.moo

@@ -128,7 +128,7 @@ class System(Apex)
 
 	method(#class) __os_sig_handler: caller
 	{
-		| os_intr_sem tmp terminate_process|
+		| os_intr_sem tmp |
 
 		os_intr_sem := Semaphore new.
 		os_intr_sem signalOnInput: System _getSigfd.
@@ -168,27 +168,32 @@ class System(Apex)
          the following loops starts from pid 3 up to 100.  this is POC only. i need to write a proper enumeration methods and use them.
       */
 
-			//Processor _suspendAllUserProcesses. <--- keep kernel processes alive.
+			//Processor _suspendUserProcesses. <--- keep kernel processes alive.
+			pid := 3.
+			while (pid < 100) 
+			{
+				proc := Processor _processById: pid.
+				if (proc notError and proc ~~ caller) { System logNl: ("Requesting to suspend process of id - " & pid asString). proc suspend }.
+				pid := pid + 1.
+			}.
 
 			pid := 3.
 			while (pid < 100) 
 			{
-				//proc := Processor processById: pid.
 				proc := Processor _processById: pid.
-				if (proc notError) { System logNl: ("Requesting to terminate process of id - " & pid asString). proc terminate }.
+				if (proc notError and proc ~~ caller) { System logNl: ("Requesting to terminate process of id - " & pid asString). proc terminate }.
 				pid := pid + 1.
 			}.
 /* TODO: end redo */
 
-			caller terminate.
+			caller terminate.  // terminate the startup process.
 
 			System logNl: '>>>>End of OS signal handler process ' & (thisProcess id) asString.
 
-			//(Processor _processById: 1) resume. //<---- i shouldn't do ths. but, this system causes VM assertion failure. fix it....
 			self.gcfin_should_exit := true.
 			self.gcfin_sem signal. // wake the gcfin process.
 
-			System _halting.
+			System _halting. // inform VM that it should get ready for halting.
 		].
 	}
 

moo/lib/comp.c

@@ -8567,11 +8567,15 @@ static int process_class_superclass (moo_t* moo)
 			if (MOO_CLASS_SELFSPEC_FLAGS(MOO_OOP_TO_SMOOI(((moo_oop_class_t)cc->super_oop)->selfspec)) & MOO_CLASS_SELFSPEC_FLAG_FINAL)
 			{
 				/* cannot inherit a #final class */
+				if (cc->self_oop == MOO_NULL) /* self_oop is not null if it's a predefined kernel class. */ 
+				{
+					/* the restriction applies to non-kernel classes only */
 					moo_setsynerrbfmt (moo, MOO_SYNERR_INHERITBANNED, &cc->fqn_loc, &cc->fqn,
 						"the %.*js class cannot inherit from a final class", cc->fqn.len, cc->fqn.ptr);
 					return -1;
 				}
 			}
+		}
 		else
 		{
 		unknown_superclass:

moo/lib/exec.c

@@ -1626,6 +1626,7 @@ static moo_oop_process_t start_initial_process (moo_t* moo, moo_oop_context_t c)
 
 	proc = make_process(moo, c);
 	if (!proc) return MOO_NULL;
+	MOO_OBJ_SET_CLASS(proc, moo->_kernel_process); /* the initial process is special */
 
 	chain_into_processor (moo, proc, PROC_STATE_RUNNING);
 	moo->processor->active = proc;
@@ -2786,13 +2787,18 @@ static moo_pfrc_t pf_process_scheduler_process_by_id (moo_t* moo, moo_mod_t* mod
 	return MOO_PF_FAILURE;
 }
 
-static moo_pfrc_t pf_process_scheduler_suspend_all_user_processes (moo_t* moo, moo_mod_t* mod, moo_ooi_t nargs)
+static moo_pfrc_t pf_process_scheduler_suspend_user_processes (moo_t* moo, moo_mod_t* mod, moo_ooi_t nargs)
 {
-	/* TODO: must exclude special inner processes */
+	moo_oop_process_t proc;
-	while (moo->processor->runnable.first)
+
+	while ((moo_oop_t)(proc = moo->processor->runnable.first) != moo->_nil)
 	{
-		suspend_process (moo, moo->processor->runnable.first);
+		/* exclude internal kernel classes. suspend user processes only */
+		if (MOO_CLASSOF(moo, proc) == moo->_process) suspend_process (moo, proc);
 	}
+
+	MOO_STACK_SETRETTORCV (moo, nargs);
+	return MOO_PF_SUCCESS;
 }
 
 /* ------------------------------------------------------------------ */
@@ -4328,7 +4334,7 @@ static pf_t pftab[] =
 	{ "MethodContext_goto:",                   { pf_context_goto,                         1, 1 } },
 
 	{ "ProcessScheduler_processById:",         { pf_process_scheduler_process_by_id,      1, 1 } },
-	{ "ProcessScheduler_suspendAllUserProcesses",  { pf_process_scheduler_suspend_all_user_processes, 0, 0 } },
+	{ "ProcessScheduler_suspendUserProcesses", { pf_process_scheduler_suspend_user_processes, 0, 0 } },
 
 	{ "Process_resume",                        { pf_process_resume,                       0, 0 } },
 	{ "Process_sp",                            { pf_process_sp,                           0, 0 } },

moo/lib/gc.c

@@ -255,7 +255,6 @@ static kernel_class_info_t kernel_classes[] =
 	  MOO_OFFSETOF(moo_t, _methsig) },
 
 
-
 	{ 13,
 	  { 'M','e','t','h','o','d','C','o','n','t','e','x','t' },
 	  MOO_CLASS_SELFSPEC_FLAG_FINAL | MOO_CLASS_SELFSPEC_FLAG_LIMITED,
@@ -283,6 +282,15 @@ static kernel_class_info_t kernel_classes[] =
 	  MOO_OBJ_TYPE_OOP,
 	  MOO_OFFSETOF(moo_t, _process) },
 
+	{ 14,
+	  { '_','K','e','r','n','e','l','P','r','o','c','e','s','s' },
+	  MOO_CLASS_SELFSPEC_FLAG_FINAL | MOO_CLASS_SELFSPEC_FLAG_LIMITED,
+	  0,
+	  MOO_PROCESS_NAMED_INSTVARS,
+	  MOO_CLASS_SPEC_FLAG_INDEXED,
+	  MOO_OBJ_TYPE_OOP,
+	  MOO_OFFSETOF(moo_t, _kernel_process) },
+
 	{ 9,
 	  { 'S','e','m','a','p','h','o','r','e' },
 	  0,

moo/lib/moo.h

@@ -1547,6 +1547,7 @@ struct moo_t
 	moo_oop_class_t _method_context; /* MethodContext */
 	moo_oop_class_t _block_context; /* BlockContext */
 	moo_oop_class_t _process; /* Process */
+	moo_oop_class_t _kernel_process; /* KernelProcess */
 	moo_oop_class_t _semaphore; /* Semaphore */
 	moo_oop_class_t _semaphore_group; /* SemaphoreGroup */
 	moo_oop_class_t _process_scheduler; /* ProcessScheduler */