Re: [PATCH for-5.0 v2 2/3] iotests: Add poke_file_[bl]e functions

[Eric Blake]

On 3/24/20 12:27 PM, Max Reitz wrote:
> Similarly to peek_file_[bl]e, we may want to write binary integers into
> a file.  Currently, this often means messing around with poke_file and
> raw binary strings.  I hope these functions make it a bit more
> comfortable.
>
> Signed-off-by: Max Reitz <address@hidden>
> Code-suggested-by: Eric Blake <address@hidden>
> ---
>   tests/qemu-iotests/common.rc | 24 ++++++++++++++++++++++++
>   1 file changed, 24 insertions(+)
>
> diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.rc
> index 4c246c0450..bf3b9fdea0 100644
> --- a/tests/qemu-iotests/common.rc
> +++ b/tests/qemu-iotests/common.rc
> @@ -53,6 +53,30 @@ poke_file()
>       printf "$3" | dd "of=$1" bs=1 "seek=$2" conv=notrunc &>/dev/null
>   }
>   
> +# poke_file_le $img_filename $offset $byte_width $value
> +# Example: poke_file_le "$TEST_IMG" 512 2 65534
> +poke_file_le()

Yep, that's nicer.

> +{
> +    local img=$1 ofs=$2 len=$3 val=$4 str=''
> +
> +    while ((len--)); do
> +        str+=$(printf '\\x%02x' $((val & 0xff)))
> +        val=$((val >> 8))
> +    done
> +
> +    poke_file "$img" "$ofs" "$str"
> +}

and so is that (but I'm biased, here :)

Reviewed-by: Eric Blake <address@hidden>

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org