Catch Zenmap's MemoryError (caused by large Nmap Output) and provide the user a more useful error message so that we get less of the out-of-memory "crash reports"

zenmap/zenmapGUI/NmapOutputViewer.py

@@ -296,8 +296,11 @@ class NmapOutputViewer (gtk.VBox):
 
     def show_nmap_output(self, output):
         """Show the string (or unicode) output in the output display."""
-        self.text_view.get_buffer().set_text(output)
-        self.apply_highlighting()
+        try:
+            self.text_view.get_buffer().set_text(output)
+            self.apply_highlighting()
+        except MemoryError:
+            self.show_large_output_message(self.command_execution)
 
     def set_command_execution(self, command):
         """Set the live running command whose output is shown by this display.
@@ -310,6 +313,31 @@ class NmapOutputViewer (gtk.VBox):
             self.output_file_pointer = None
         self.refresh_output()
 
+    def show_large_output_message(self, command=None):
+        buf = self.text_view.get_buffer()
+        try:
+            running = (command is not None and command.scan_state() is True)
+        except:
+            running = False
+            complete = False
+        else:
+            complete = not running
+        if running:
+            buf.set_text("Warning: You have insufficient resources for Zenmap "
+                "to be able to display the complete output from Nmap here. \n"
+                "Zenmap will continue to run the scan to completion. However,"
+                " some features of Zenmap might not work as expected.")
+        elif complete:
+            buf.set_text("Warning: You have insufficient resources for Zenmap "
+                "to be able to display the complete output from Nmap here. \n"
+                "The scan has completed. However, some features of Zenmap "
+                "might not work as expected.")
+        else:
+            buf.set_text("Warning: You have insufficient resources for Zenmap "
+                "to be able to display the complete output from Nmap here. \n"
+                "The scan has been stopped. Some features of Zenmap might not "
+                "work as expected.")
+
     def refresh_output(self, widget=None):
         """Update the output from the latest output of the command associated
         with this view, as set by set_command_execution. It has no effect if no
@@ -322,7 +350,13 @@ class NmapOutputViewer (gtk.VBox):
         # Seek to the end of the most recent read.
         self.command_execution.stdout_file.seek(self.output_file_pointer)
         pos = self.command_execution.stdout_file.tell()
-        new_output = self.command_execution.stdout_file.read()
+
+        try:
+            new_output = self.command_execution.stdout_file.read()
+        except MemoryError:
+            self.show_large_output_message(self.command_execution)
+            return
+
         self.output_file_pointer = self.command_execution.stdout_file.tell()
         # print "read %d -> %d %d" % (
         #         pos, self.output_file_pointer, len(new_output))
@@ -335,10 +369,14 @@ class NmapOutputViewer (gtk.VBox):
             buf = self.text_view.get_buffer()
             prev_end_mark = buf.create_mark(
                     None, buf.get_end_iter(), left_gravity=True)
-            buf.insert(buf.get_end_iter(), new_output)
-            # Highlight the new text.
-            self.apply_highlighting(
-                    buf.get_iter_at_mark(prev_end_mark), buf.get_end_iter())
+            try:
+                buf.insert(buf.get_end_iter(), new_output)
+                # Highlight the new text.
+                self.apply_highlighting(
+                        buf.get_iter_at_mark(prev_end_mark), buf.get_end_iter())
+            except MemoryError:
+                self.show_large_output_message(self.command_execution)
+                return
 
             if at_end:
                 # If we were already scrolled to the bottom, scroll back to the