Re: [PATCH] allow nested sourced commands

[Michael Snyder <msnyder@redhat.com>]

Andrew STUBBS wrote:
>>
>>> I have discovered a problem in the GDB command line reading code.
>>>
>>> command_line_input() uses a static buffer to hold the current 
>>> command. This means that it is not properly re-entrant - commands 
>>> that contain other commands, such as user defined commands, are not 
>>> handled safely.
>>
>>
>> See http://sources.redhat.com/ml/gdb-patches/2006-03/msg00356.html
>>
>> The attached patch should fix the problem.
>>
>> I tried to fix the problem in command_line_input, but there were too 
>> many ways for the string to leak, so I have opted for the simpler fix, 
>> even though it feels like treating the symptoms, not the problem.
>>
>> Anyway, with this patch it no longer attempts to read data that has 
>> been overwritten, so everything works fine. Valgrind reports no 
>> problems with
>> the test case I posted before.
>>
>> Andrew Stubbs

Well, it has the virtue of simplicity!
At first glance, it seems conceptually valid.

I think you need a clean-up, though.  What if it errors?


> ------------------------------------------------------------------------
> 
> 2006-04-04  Andrew Stubbs  <andrew.stubbs@st.com>
> 
> 	* cli/cli-script.c (struct user_args): Add command field.
> 	(arg_cleanup): Free command string.
> 	(setup_user_args): Copy the command line before relying on it.
> 
> Index: src/gdb/cli/cli-script.c
> ===================================================================
> --- src.orig/gdb/cli/cli-script.c	2006-04-04 10:53:26.000000000 +0100
> +++ src/gdb/cli/cli-script.c	2006-04-04 11:09:33.000000000 +0100
> @@ -54,6 +54,7 @@ static int control_level;
>  struct user_args
>    {
>      struct user_args *next;
> +    char *command;
>      struct
>        {
>  	char *arg;
> @@ -483,6 +484,7 @@ arg_cleanup (void *ignore)
>  		    _("arg_cleanup called with no user args.\n"));
>  
>    user_args = user_args->next;
> +  xfree (oargs->command);
>    xfree (oargs);
>  }
>  
> @@ -507,6 +509,8 @@ setup_user_args (char *p)
>    if (p == NULL)
>      return old_chain;
>  
> +  user_args->command = p = xstrdup (p);
> +
>    while (*p)
>      {
>        char *start_arg;