scripts: add debugger command to dump the free memory heap

(gdb) osv heap

scripts/loader.py

@@ -38,3 +38,29 @@ class Connect(gdb.Command):
         gdb.execute('target remote :1234')
 
 Connect()
+
+class osv(gdb.Command):
+    def __init__(self):
+        gdb.Command.__init__(self, 'osv',
+                             gdb.COMMAND_USER, gdb.COMPLETE_COMMAND, True)
+
+class osv_heap(gdb.Command):
+    def __init__(self):
+        gdb.Command.__init__(self, 'osv heap',
+                             gdb.COMMAND_USER, gdb.COMPLETE_NONE)
+    def invoke(self, arg, from_tty):
+        free_page_ranges = gdb.lookup_global_symbol('memory::free_page_ranges').value()
+        p = free_page_ranges['tree_']['data_']['node_plus_pred_']
+        p = p['header_plus_size_']['header_']['parent_']
+        self.show(p)
+    def show(self, node):
+        if long(node) == 0:
+            return
+        page_range = node.cast(gdb.lookup_type('void').pointer()) - 8
+        page_range = page_range.cast(gdb.lookup_type('memory::page_range').pointer())
+        self.show(node['left_'])
+        print page_range, page_range['size']
+        self.show(node['right_'])
+
+osv()
+osv_heap()