[PATCH v3 2/4] efi_loader: function to get GUID for variable name

[Ilias Apalodimas]

On Sun, Oct 03, 2021 at 11:23:18AM +0200, Heinrich Schuchardt wrote:
> In multiple places we need the default GUID matching a variable name.
> The patch provides a library function. For secure boot related variables
> like 'PK', 'KEK', 'db' a lookup table is used. For all other variable
> names EFI_GLOBAL_VARIABLE is returned.
> 
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> ---
> v3:
> 	no change
> v2:
> 	adjust function documentation
> ---
>  include/efi_variable.h          | 11 +++++++++++
>  lib/efi_loader/efi_var_common.c |  9 +++++++++
>  2 files changed, 20 insertions(+)
> 
> diff --git a/include/efi_variable.h b/include/efi_variable.h
> index 8f666b2309..74909e8ec6 100644
> --- a/include/efi_variable.h
> +++ b/include/efi_variable.h
> @@ -256,6 +256,17 @@ efi_status_t efi_init_secure_state(void);
>  enum efi_auth_var_type efi_auth_var_get_type(const u16 *name,
>  					     const efi_guid_t *guid);
>  
> +/**
> + * efi_auth_var_get_guid() - get the predefined GUID for a variable name
> + *
> + * For secure boot related variables a lookup table is used to determine
> + * the GUID. For all other variables EFI_GLOBAL_VARIABLE is returned.
> + *
> + * @name:	name of UEFI variable
> + * Return:	guid of UEFI variable
> + */
> +const efi_guid_t *efi_auth_var_get_guid(const u16 *name);
> +
>  /**
>   * efi_get_next_variable_name_mem() - Runtime common code across efi variable
>   *                                    implementations for GetNextVariable()
> diff --git a/lib/efi_loader/efi_var_common.c b/lib/efi_loader/efi_var_common.c
> index e179932124..3cbb7c96c2 100644
> --- a/lib/efi_loader/efi_var_common.c
> +++ b/lib/efi_loader/efi_var_common.c
> @@ -385,6 +385,15 @@ enum efi_auth_var_type efi_auth_var_get_type(const u16 *name,
>  	return EFI_AUTH_VAR_NONE;
>  }
>  
> +const efi_guid_t *efi_auth_var_get_guid(const u16 *name)
> +{
> +	for (size_t i = 0; i < ARRAY_SIZE(name_type); ++i) {
> +		if (!u16_strcmp(name, name_type[i].name))
> +			return name_type[i].guid;
> +	}
> +	return &efi_global_variable_guid;
> +}
> +
>  /**
>   * efi_get_var() - read value of an EFI variable
>   *
> -- 
> 2.32.0
> 

Reviewed-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>