vm: allocate stacks and data heap segments without execute permissions

vm/code_heap.cpp

@@ -3,7 +3,7 @@
 namespace factor
 {
 
-code_heap::code_heap(bool secure_gc, cell size) : heap(secure_gc,size) {}
+code_heap::code_heap(bool secure_gc, cell size) : heap(secure_gc,size,true) {}
 
 void code_heap::write_barrier(code_block *compiled)
 {

vm/contexts.cpp

@@ -44,8 +44,8 @@ context *factor_vm::alloc_context()
 	else
 	{
 		new_context = new context;
-		new_context->datastack_region = new segment(ds_size);
+		new_context->datastack_region = new segment(ds_size,false);
-		new_context->retainstack_region = new segment(rs_size);
+		new_context->retainstack_region = new segment(rs_size,false);
 	}
 
 	return new_context;

vm/data_heap.cpp

@@ -23,7 +23,7 @@ data_heap::data_heap(cell young_size_, cell aging_size_, cell tenured_size_)
 
 	total_size += deck_size;
 
-	seg = new segment(total_size);
+	seg = new segment(total_size,false);
 
 	cell cards_size = addr_to_card(total_size);
 

vm/heap.cpp

@@ -11,10 +11,10 @@ void heap::clear_free_list()
 	memset(&free,0,sizeof(heap_free_list));
 }
 
-heap::heap(bool secure_gc_, cell size) : secure_gc(secure_gc_)
+heap::heap(bool secure_gc_, cell size, bool executable_p) : secure_gc(secure_gc_)
 {
 	if(size > (1L << (sizeof(cell) * 8 - 6))) fatal_error("Heap too large",size);
-	seg = new segment(align_page(size));
+	seg = new segment(align_page(size),executable_p);
 	if(!seg) fatal_error("Out of memory in heap allocator",size);
 	clear_free_list();
 }

vm/heap.hpp

@@ -15,7 +15,7 @@ struct heap {
 	heap_free_list free;
 	unordered_map<heap_block *, char *> forwarding;
 
-	explicit heap(bool secure_gc_, cell size);
+	explicit heap(bool secure_gc_, cell size, bool executable_p);
 
 	inline heap_block *next_block(heap_block *block)
 	{

vm/os-unix.cpp

@@ -83,16 +83,19 @@ void factor_vm::primitive_existsp()
 	box_boolean(stat(path,&sb) >= 0);
 }
 
-segment::segment(cell size_)
+segment::segment(cell size_, bool executable_p)
 {
 	size = size_;
 
 	int pagesize = getpagesize();
 
-	char *array = (char *)mmap(NULL,pagesize + size + pagesize,
+	int prot;
-		PROT_READ | PROT_WRITE | PROT_EXEC,
+	if(executable_p)
-		MAP_ANON | MAP_PRIVATE,-1,0);
+		prot = (PROT_READ | PROT_WRITE | PROT_EXEC);
+	else
+		prot = (PROT_READ | PROT_WRITE);
 
+	char *array = (char *)mmap(NULL,pagesize + size + pagesize,prot,MAP_ANON | MAP_PRIVATE,-1,0);
 	if(array == (char*)-1) out_of_memory();
 
 	if(mprotect(array,pagesize,PROT_NONE) == -1)

vm/os-windows.cpp

@@ -96,7 +96,7 @@ void factor_vm::primitive_existsp()
 	box_boolean(windows_stat(path));
 }
 
-segment::segment(cell size_)
+segment::segment(cell size_, bool executable_p)
 {
 	size = size_;
 
@@ -104,7 +104,7 @@ segment::segment(cell size_)
 	DWORD ignore;
 
 	if((mem = (char *)VirtualAlloc(NULL, getpagesize() * 2 + size,
-		MEM_COMMIT, PAGE_EXECUTE_READWRITE)) == 0)
+		MEM_COMMIT, executable_p ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE)) == 0)
 		out_of_memory();
 
 	if (!VirtualProtect(mem, getpagesize(), PAGE_NOACCESS, &ignore))

vm/segments.hpp

@@ -13,7 +13,7 @@ struct segment {
 	cell size;
 	cell end;
 
-	explicit segment(cell size);
+	explicit segment(cell size, bool executable_p);
 	~segment();
 };