[U-Boot] [RFC v3 01/10] efi_loader: device_path: handle special case of loading

[Heinrich Schuchardt]

On 4/16/19 6:24 AM, AKASHI Takahiro wrote:
> This is a preparatory patch.
>
> efi_dp_split_file_path() is used to create device_path and file_path
> from file_path for efi_setup_loaded_image().
> In a special case, however, of HARDWARE_DEVICE/MEMORY, it doesn't
> work expectedly since this path doesn't contain any FILE_PATH sub-type.
>
> This patch makes a workaround.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> ---
>   lib/efi_loader/efi_device_path.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
>
> diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c
> index 53b40c8c3c2d..e283fad767ed 100644
> --- a/lib/efi_loader/efi_device_path.c
> +++ b/lib/efi_loader/efi_device_path.c
> @@ -933,6 +933,14 @@ efi_status_t efi_dp_split_file_path(struct efi_device_path *full_path,
>   	dp = efi_dp_dup(full_path);
>   	if (!dp)
>   		return EFI_OUT_OF_RESOURCES;
> +
> +	if (EFI_DP_TYPE(dp, HARDWARE_DEVICE, MEMORY)) {
> +		/* no FILE_PATH */
> +		*device_path = dp;
> +
> +		return EFI_SUCCESS;
> +	}
> +
>   	p = dp;
>   	while (!EFI_DP_TYPE(p, MEDIA_DEVICE, FILE_PATH)) {
>   		p = efi_dp_next(p);
>

Should we really give device paths *starting* with a memory node a
special treatment?

Or should we simply handle all cases where the device path does not end
on a file path the same, e.g.:

diff --git a/lib/efi_loader/efi_device_path.c
b/lib/efi_loader/efi_device_path.c
index d8c052d6ec..d0fd154f54 100644
--- a/lib/efi_loader/efi_device_path.c
+++ b/lib/efi_loader/efi_device_path.c
@@ -924,7 +924,7 @@ efi_status_t efi_dp_split_file_path(struct
efi_device_path *full_path,
                                     struct efi_device_path **device_path,
                                     struct efi_device_path **file_path)
  {
-       struct efi_device_path *p, *dp, *fp;
+       struct efi_device_path *p, *dp, *fp = NULL;

         *device_path = NULL;
         *file_path = NULL;
@@ -935,7 +935,7 @@ efi_status_t efi_dp_split_file_path(struct
efi_device_path *full_path,
         while (!EFI_DP_TYPE(p, MEDIA_DEVICE, FILE_PATH)) {
                 p = efi_dp_next(p);
                 if (!p)
-                       return EFI_INVALID_PARAMETER;
+                       goto out;
         }
         fp = efi_dp_dup(p);
         if (!fp)
@@ -944,6 +944,7 @@ efi_status_t efi_dp_split_file_path(struct
efi_device_path *full_path,
         p->sub_type = DEVICE_PATH_SUB_TYPE_END;
         p->length = sizeof(*p);

+out:
         *device_path = dp;
         *file_path = fp;
         return EFI_SUCCESS;

I would prefer to go for the more generic version.

Best regards

Heinrich