Re: [RFA] Avoid recursivly defined user functions.

[Don Howard <dhoward@redhat.com>]

On Fri, 12 Apr 2002, Fernando Nasser wrote:

> Michael Snyder wrote:
> > 
> > Andreas Schwab wrote:
> > >
> > > Don Howard <dhoward@redhat.com> writes:
> > >
> > > |> +
> > > |> +  add_show_from_set (
> > > |> +                  add_set_cmd ("max_user_call_depth", no_class, var_integer,
> > >
> > > I think this should use hyphens instead of underscores.
> > 
> > Yeah, that's sort of the unwritten convention.
> > Other than that, I like it.
> 
> So do I.  It is approved conditional to this fix and the documentation.
> 
> (No need to resubmit -- just post the final version committed)
>  


Thanks. I've comitted the following:


Index: ChangeLog
===================================================================
RCS file: /cvs/src/src/gdb/ChangeLog,v
retrieving revision 1.2423
diff -p -u -w -r1.2423 ChangeLog
--- ChangeLog	12 Apr 2002 18:18:56 -0000	1.2423
+++ ChangeLog	12 Apr 2002 20:40:55 -0000
@@ -1,3 +1,12 @@
+2002-04-12  Don Howard  <dhoward@redhat.com>
+
+	* cli/cli-cmds.c (init_cli_cmds): Add new user settable value:
+	max_user_call_depth.
+	(init_cmd_lists): Initialize the new value;
+	* cli/cli-script.c (execute_user_command): Limit the call depth of
+	user defined commands.  This avoids a core-dump when user commands
+	are infinitly recursive.
+
 2002-04-12  Andrew Cagney  <cagney@redhat.com>
 
 	* defs.h (read_relative_register_raw_bytes): Delete declaration.
Index: NEWS
===================================================================
RCS file: /cvs/src/src/gdb/NEWS,v
retrieving revision 1.61
diff -p -u -w -r1.61 NEWS
--- NEWS	31 Mar 2002 17:53:00 -0000	1.61
+++ NEWS	12 Apr 2002 20:41:05 -0000
@@ -3,6 +3,11 @@
 
 *** Changes since GDB 5.2:
 
+* New command "set max-user-call-depth <nnn>"
+
+This command allows the user to limit the call depth of user-defined
+commands.  The default is 1024.
+
 * Changes in FreeBSD/i386 native debugging.
 
 Support for the "generate-core-file" has been added.
Index: cli/cli-cmds.c
===================================================================
RCS file: /cvs/src/src/gdb/cli/cli-cmds.c,v
retrieving revision 1.18
diff -p -u -w -r1.18 cli-cmds.c
--- cli/cli-cmds.c	28 Mar 2002 01:35:56 -0000	1.18
+++ cli/cli-cmds.c	12 Apr 2002 20:41:07 -0000
@@ -80,6 +80,9 @@ static void shell_escape (char *, int);
 
 void apropos_command (char *, int);
 \f
+/* Limit the call depth of user-defined commands */
+int max_user_call_depth;
+
 /* Define all cmd_list_elements.  */
 
 /* Chain containing all defined commands.  */
@@ -606,6 +609,8 @@ show_debug (char *args, int from_tty)
 void
 init_cmd_lists (void)
 {
+  max_user_call_depth = 1024;
+
   cmdlist = NULL;
   infolist = NULL;
   enablelist = NULL;
@@ -823,4 +828,11 @@ With no arguments, run an inferior shell
 Argument is the name of the user defined command.\n\
 With no argument, show definitions of all user defined commands.", &showlist);
   add_com ("apropos", class_support, apropos_command, "Search for commands matching a REGEXP");
+
+  add_show_from_set (
+		      add_set_cmd ("max-user-call-depth", no_class, var_integer, 
+				   (char *) &max_user_call_depth,
+				   "Set the max call depth for user-defined commands.\n", 
+				   &setlist),
+		      &showlist);
 }
Index: cli/cli-script.c
===================================================================
RCS file: /cvs/src/src/gdb/cli/cli-script.c,v
retrieving revision 1.11
diff -p -u -w -r1.11 cli-script.c
--- cli/cli-script.c	17 Mar 2002 19:53:39 -0000	1.11
+++ cli/cli-script.c	12 Apr 2002 20:41:10 -0000
@@ -247,6 +247,15 @@ execute_cmd_post_hook (struct cmd_list_e
 }
 
 /* Execute the command in CMD.  */
+void
+do_restore_user_call_depth (void * call_depth)
+{	
+  int * depth = call_depth;
+  /* We will be returning_to_top_level() at this point, so we want to
+     reset our depth. */
+  (*depth) = 0;
+}
+
 
 void
 execute_user_command (struct cmd_list_element *c, char *args)
@@ -254,6 +263,8 @@ execute_user_command (struct cmd_list_el
   register struct command_line *cmdlines;
   struct cleanup *old_chain;
   enum command_control_type ret;
+  static int user_call_depth = 0;
+  extern int max_user_call_depth;
 
   old_chain = setup_user_args (args);
 
@@ -262,6 +273,11 @@ execute_user_command (struct cmd_list_el
     /* Null command */
     return;
 
+  if (++user_call_depth > max_user_call_depth)
+    error ("Max user call depth exceeded -- command aborted\n");
+
+  old_chain = make_cleanup (do_restore_user_call_depth, &user_call_depth);
+
   /* Set the instream to 0, indicating execution of a
      user-defined function.  */
   old_chain = make_cleanup (do_restore_instream_cleanup, instream);
@@ -277,6 +293,8 @@ execute_user_command (struct cmd_list_el
       cmdlines = cmdlines->next;
     }
   do_cleanups (old_chain);
+
+  user_call_depth--;
 }
 
 enum command_control_type
Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.95
diff -p -u -w -r1.95 gdb.texinfo
--- doc/gdb.texinfo	7 Apr 2002 19:09:58 -0000	1.95
+++ doc/gdb.texinfo	12 Apr 2002 20:41:42 -0000
@@ -12781,6 +12781,13 @@ Display the @value{GDBN} commands used t
 not its documentation).  If no @var{commandname} is given, display the
 definitions for all user-defined commands.
 
+@kindex show max-user-call-depth
+@kindex set max-user-call-depth
+@item show max-user-call-depth
+@item set max-user-call-depth
+The value of @code{max-user-call-depth} controls how many levels deep a
+user-defined call chain can go.  Default is 1024.
+
 @end table
 
 When user-defined commands are executed, the





-- 
dhoward@redhat.com
gdb engineering