Command line editing give a wrong result for me on hush shell 1.9.1

[Denys Vlasenko]

On Tuesday 19 February 2008 01:58, Martinb_ARM_NOMMU_KISSDVD wrote:
> Its hard to believe but that's just the point
> if I leave your comments its working
> 
> if I do "./hush 2>/dev/null" it ok
> 
> but if I remove the comments and recompile its NOT ok
> I don't get this ?
> the code is:
> 
>     if (cmdedit_x >= num) {
>         const char *bbbb = "\b\b\b\b";
> //bb_error_msg("\n initial bbbb=%02x %02x %02x %02x (%p)", bbbb[0], bbbb[1],
> bbbb[2], bbbb[3], bbbb);
>         cmdedit_x -= num;
> bbbb += 4;
>         if (num <= 4) {
>             bbbb -= num;
> //asm volatile("# HERE");
> //bb_error_msg("\n bbbb=%02x %02x %02x %02x (%p)", bbbb[0], bbbb[1],
> bbbb[2], bbbb[3], bbbb);
>             printf(bbbb);
>             return;
>         }
>         printf("\033[%uD", num);
>         return;
>     }
> 
> so if I compile with the // its NOT ok
> if I compile with the // removed its ok (if I redirect the comment to null)
> ??

"??" indeed.

It leaves me only with two teories which explain these symptoms:

1. Memory corruption
2. Miscompilation (gcc bug).

Second one is less likely as I looked at assembly and it seems to be ok.

Anyway, I plan to apply this to 1.9.2:
http://busybox.net/downloads/fixes-1.9.1/busybox-1.9.1-lineedit.patch
--
vda