Re: [Qemu-devel] [PATCH v5 1/2] loader: Add load_image_gzipped function.

["Richard W.M. Jones" <rjones@redhat.com>]

On Tue, Aug 05, 2014 at 10:57:26AM +0100, Alex Bennée wrote:
> 
> Richard W.M. Jones writes:
> 
> > As the name suggests this lets you load a ROM/disk image that is
> > gzipped.  It is uncompressed before storing it in guest memory.
> >
> > Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
> <snip>
> > +    /* Is it a gzip-compressed file? */
> > +    if (len < 2 ||
> > +        compressed_data[0] != '\x1f' ||
> > +        compressed_data[1] != '\x8b') {
> > +        goto out;
> > +    }
> <snip>
> 
> Hmm serves me right for not compiling this first. I had to explicit
> literals to get this to compile:
> 
> 	Modified   hw/core/loader.c
> diff --git a/hw/core/loader.c b/hw/core/loader.c
> index e773aab..83136e8 100644
> --- a/hw/core/loader.c
> +++ b/hw/core/loader.c
> @@ -599,8 +599,8 @@ int load_image_gzipped(const char *filename, hwaddr addr, uint64_t max_sz)
>  
>      /* Is it a gzip-compressed file? */
>      if (len < 2 ||
> -        compressed_data[0] != '\x1f' ||
> -        compressed_data[1] != '\x8b') {
> +        compressed_data[0] != 0x1f ||
> +        compressed_data[1] != 0x8b ) {
>          goto out;
>      }
> 
> Otherwise I get:
> hw/core/loader.c: In function ‘load_image_gzipped’:
> hw/core/loader.c:603:9: error: comparison is always true due to limited range of data type [-Werror=type-limits]
>          compressed_data[1] != '\x8b') {

This is probably because I only compiled and tested this on aarch64
where char == unsigned char (not signed char).

I'll fix this in v6, thanks.

Rich.

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