Re: [RFA] Avoid recursivly defined user functions.

Don Howard
2002-04-12T22:32:50Z

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