Re: [PATCH 7/8] xl: generate a new random VM generation ID if requested

[Ian Campbell <Ian.Campbell@citrix.com>]

On Thu, 2014-06-12 at 16:04 +0100, David Vrabel wrote:
> diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
> index 64a1c77..ad50e21 100644
> --- a/tools/libxl/xl_cmdimpl.c
> +++ b/tools/libxl/xl_cmdimpl.c
> @@ -1021,6 +1021,15 @@ static void parse_config_data(const char *config_source,
>                                 &b_info->u.hvm.smbios_firmware, 0);
>          xlu_cfg_replace_string(config, "acpi_firmware",
>                                 &b_info->u.hvm.acpi_firmware, 0);
> +
> +        /* Generate and set a new random VM Generation ID? */
> +        if (!xlu_cfg_get_long(config, "generation_id", &l, 0)) {

xlu_cfg_* returns present/notpresent not the value. You need to check
the actual value of l here. Otherwise generation_id=0 in the cfg will
cause it to be unexpectedly generated.

Did you want to rename this key to ms_vm_genid for consistency?

I suppose there is no call for actually specifying a genid? If there
were then I'd suggest 
	ms_vm_genid = "generate"

as the syntax leaving the way open for a future extension of giving a
number here.

> +            e = libxl_ms_vm_genid_generate(ctx, &b_info->u.hvm.ms_vm_genid);
> +            if (e) {
> +                fprintf(stderr, "ERROR: no random numbers available for \"generation_id\"\n");

That's very specific. How about "unable to generate ..."?