[PATCH] blspec: add checking of optional key machine-id

[Sascha Hauer]

Hi Andreas,

On Sun, Apr 29, 2018 at 06:01:25PM +0200, Andreas Schmidt wrote:
> For filtering of Bootloader Spec entries, Bootloader Spec
> specify an optional key machine-id. By set the
> global.boot.machine-id variable the checking of machine-id
> key in Bootloader Spec entries will be activate. If the
> variable and key match, appropriate boot entry will be
> booting. If it not match boot entry will be ignore and
> barebox check the next boot entry.
> 
> Signed-off-by: Andreas Schmidt <mail at schmidt-andreas.de>
> ---
> Hi,
> we use the same barebox for all our devices. The devices have
> same CPU-module but different interface boards. So the bootloader
> has to choose the right boot entry. To determine the right boot entry we
> decide to use Bootloader Spec. But we have a issue: Currently, only oftree 
> compatibility is checking by barebox for Bootloader Spec entries. But all 
> our ofstrees are compatible with our barebox, because we use only one. So
> we need a additional possibility to check witch Bootloader Spec entry
> is the right one for appropriate device. I guess, for such an use case
> Bootloader Spec specify "machine-id" key. This patch implement the support
> for machine-id key.
> The machine-id key is optional. I decide to activate the checking of this
> key only if "global.boot.machine_id" variable is set to non-empty value.
> If "global.boot.machine_id" not set machine-id key will be ignored, 
> independent if it exists in Bootloader Spec entry or not.

I like the idea and the patch looks mosty fine.

> +static bool entry_is_match_machine_id(struct blspec_entry *entry)
> +{
> +	int ret = true;
> +	const char *env_machineid = getenv_nonempty("global.boot.machine_id");
> +
> +	if (env_machineid) {
> +		const char *machineid = blspec_entry_var_get(entry, "machine-id");
> +		if (!machineid || strcmp(machineid, env_machineid)) {
> +			pr_info("ignoring entry with missmatched machine-id \"%s\"\n",
> +				env_machineid);

Don't you want to print the machine id of the current entry rather than
the desired machine id?

Sascha

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