Re: [RFA] Resubmit reverse debugging [5/5]

Michael Snyder
2008-10-08T21:06:17Z

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Thiago Jung Bauermann wrote:
> El mar, 07-10-2008 a las 19:20 -0700, Michael Snyder escribiÃ³:
>> +static void
>> +exec_reverse_once (char *cmd, char *args, int from_tty)
>> +{
>> + /* String buffer for command consing. */
>> + char reverse_command[512];
> <snip>
>> + sprintf (reverse_command, "%s %s", cmd, args ? args : "");
>> +
>> + execution_direction = EXEC_REVERSE;
>> + execute_command (reverse_command, from_tty);
>> + do_cleanups (old_chain);
>
> That fixed-length buffer being written with sprintf doesn't look good...
> What do you think about using xstrprintf instead? That will remove the
> possibility of buffer overflow, and also remove an arbitrary limit.

How about this? (the function pointer idea I leave for a future
enhancement):

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Index: reverse.c
===================================================================
RCS file: /cvs/src/src/gdb/Attic/reverse.c,v
retrieving revision 1.1.10.6
diff -u -p -r1.1.10.6 reverse.c
--- reverse.c 8 Oct 2008 00:26:28 -0000 1.1.10.6
+++ reverse.c 8 Oct 2008 21:03:59 -0000
@@ -44,8 +44,7 @@ static void exec_direction_default (void
static void
exec_reverse_once (char *cmd, char *args, int from_tty)
{
- /* String buffer for command consing. */
- char reverse_command[512];
+ char *reverse_command;
enum exec_direction_kind dir = execution_direction;
struct cleanup *old_chain;

@@ -59,9 +58,9 @@ exec_reverse_once (char *cmd, char *args
if (!target_can_execute_reverse)
error (_("Target %s does not support this command."), target_shortname);

+ reverse_command = xstrprintf ("%s %s", cmd, args ? args : "");
old_chain = make_cleanup (exec_direction_default, NULL);
- sprintf (reverse_command, "%s %s", cmd, args ? args : "");
-
+ make_cleanup (xfree, reverse_command);
execution_direction = EXEC_REVERSE;
execute_command (reverse_command, from_tty);
do_cleanups (old_chain);