Re: [Qemu-devel] [5531] Replace uses of strncpy (a GNU extension) with Qemu pstrcpy

[malc]

On Sat, 25 Oct 2008, Blue Swirl wrote:

> Revision: 5531
>          http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5531
> Author:   blueswir1
> Date:     2008-10-25 11:21:28 +0000 (Sat, 25 Oct 2008)

[..snip..]

> Modified: trunk/block-vvfat.c
> ===================================================================
> --- trunk/block-vvfat.c 2008-10-25 11:19:14 UTC (rev 5530)
> +++ trunk/block-vvfat.c 2008-10-25 11:21:28 UTC (rev 5531)
> @@ -625,7 +625,7 @@
>
>     entry=array_get_next(&(s->directory));
>     memset(entry->name,0x20,11);
> -    strncpy((char*)entry->name,filename,i);
> +    pstrcpy((char*)entry->name, i, filename);
>
>     if(j > 0)
>         for (i = 0; i < 3 && filename[j+1+i]; i++)

This is wrong and broke vvfat:

a. pstrcpy is abused, second argument should be the size of the output
   buffer, not the length of the second argument

b. even if replaced with pstrcpy(.., meta_sizeof(entry->name), ...)
   it would have been still wrong, since we must _i_ elements of
   entry->name and NOT try to zero terminate the output buffer

I think this was one of those rare cases when strncpy was used in
accordance with it's definition and not what programmer was imagining.

I think plain memcpy(...,filename,i) is the most warranted thing here.

[..snip..]

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