[BProc] Re: beoboot-cm1.9 - bug in modhelper

[<er...@he...>]

On Tue, Aug 10, 2004 at 03:26:37PM -0600, Michal Jaegermann wrote:
> 
> There is a bug in a function show_deps(), modhelper.c, from
> beoboot-cm1.9.  The code goes like that:
> 
>     while (p && *p) {
>         np = strchr(p, ',');
>         printf("%.*s", np-p, p)
> 
> If there is no comma in a string p then np is set to NULL and
> np-p may overflow the second argument to printf which happens to
> be int.  When this happens, which is pretty likely on 64-bit platforms,
> then printf errors out, returns a negaive value and nothing is printed.
> If you wonder I got hit by that. :-)  On x86 you may usually get
> away with this.
> 
> Here is a fix:
> 
> --- beoboot-cm1.9/modhelper.c~	2004-04-19 11:07:31.000000000 -0600
> +++ beoboot-cm1.9/modhelper.c	2004-08-10 15:00:13.377034440 -0600
> @@ -236,11 +236,13 @@
>      p = deps;
>      while (p && *p) {
>  	np = strchr(p, ',');
> -	printf("%.*s", np-p, p);
> -	if (np) {
> -	    printf(" ");
> +	if (np != NULL) {
> +	    printf("%.*s ", (int)(np-p), p);
>  	    np++;
>  	}
> +	else {
> +	    printf("%s", p);
> +	}
>  	p = np;
>      }
>      printf("\n");
> 
> OTOH 'modhelper -d' is used in /usr/bin/beoboot script only in
> this function:
> 
> module_dep() {
>     local MODDIR="$1"
>     local MOD="$2"
>     local DEPS=
>     local dep
>     DEPS=`module_expand $MODDIR \`$BEOLIB/bin/modhelper -d "$MOD"\``
>     for dep in $DEPS; do
>         echo "$dep"
>         module_dep "$MODDIR" "$dep"
>     done
> }
> 
> which could be simply rewritten as
> 
> module_dep() {
>     [ -r "$1/modules.dep" ] || depmod
>     sed -n 's!'"$2"': *!!p' "$1/modules.dep"
> }
> 
> making all this recursion unnecessary (and skirting the bug in the
> process).

Sounds good to me.  I'll take the simple road.  I think modhelper
started life as a prototype for the module loading code in the boot
program.

I'm glad they got rid of those @#!$ stupid newline escapes in
modules.dep.

- Erik