Re: setitimer will need a range check

[Michal Jaegermann <michal harddata com>]

On Fri, Dec 29, 2006 at 12:41:35PM -0800, John Harper wrote:
> Hi,
> 
> It's a long time since I've looked at this code, but it looks like  
> this is what the fix_time function in that file is trying to achieve -  
> i.e. ensure that 0 <= msecs < 1000.

Indeed, this is a miliseconds range and that would be somewhat
narrower than a microseconds range allowed by setitimer().  A small
problem is that fix_time is not doing what is advertised unless
changed in such way:

--- librep/src/timers.c~	2002-03-01 22:22:53.000000000 -0700
+++ librep/src/timers.c	2006-12-29 14:27:41.000000000 -0700
@@ -128,7 +128,7 @@ fix_time (long *secs, long *msecs)
 	*msecs += 1000;
 	(*secs)--;
     }
-    while (*msecs > 1000)
+    while (*msecs >= 1000)
     {
 	*msecs -= 1000;
 	(*secs)++;

> I think the change below should  
> use that function to fix the bad values to setitimer, can you confirm  
> that?

A quick run with fix_time modification seems to suggest that the
above would be enough.  OTOH it is possible that in some other
situations out-of-range values can be passed to timers in places you
marked in your patch so applying it as well would be at least
prudent.

> 
> diff -u -p -r1.15 timers.c
> --- timers.c	2 Mar 2002 05:22:53 -0000	1.15
> +++ timers.c	29 Dec 2006 20:39:56 -0000
> @@ -252,6 +252,7 @@ to re-enable it.
>      t->function = fun;
>      t->secs = rep_get_long_int (secs);
>      t->msecs = rep_get_long_int (msecs);
> +    fix_time (&t->secs, &t->msecs);
>      t->next_alloc = allocated_timers;
>      allocated_timers = t;
>      insert_timer (t);
> @@ -290,6 +291,7 @@ duration. Otherwise, the existing values
>      {
>  	TIMER(timer)->secs = rep_get_long_int (secs);
>  	TIMER(timer)->msecs = rep_get_long_int (msecs);
> +	fix_time (&TIMER (timer)->secs, &TIMER (timer)->msecs);
>      }
>      insert_timer (TIMER(timer));
>      return timer;

  Michal