efi_loader: support booting via short-form device-path

The boot manager must support loading from boot options using a short-form
device-path, e.g. one where the first element is a hard drive media path.

See '3.1.2 Load Options Processing' in UEFI specification version 2.9.

Fixes: 0e074d12393b ("efi_loader: carve out efi_load_image_from_file()")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index a7bc371f5412177b5b248c0622a691d28c4f30e5..5bcb8253edbaad5bfb36ec4ae9f471cd2891b790 100644 (file)
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -1940,7 +1940,7 @@ efi_status_t efi_load_image_from_path(bool boot_policy,
 {
        efi_handle_t device;
        efi_status_t ret;
-       struct efi_device_path *dp;
+       struct efi_device_path *dp, *rem;
        struct efi_load_file_protocol *load_file_protocol = NULL;
        efi_uintn_t buffer_size;
        uint64_t addr, pages;
@@ -1951,18 +1951,18 @@ efi_status_t efi_load_image_from_path(bool boot_policy,
        *size = 0;
 
        dp = file_path;
-       ret = EFI_CALL(efi_locate_device_path(
-                      &efi_simple_file_system_protocol_guid, &dp, &device));
+       device = efi_dp_find_obj(dp, NULL, &rem);
+       ret = efi_search_protocol(device, &efi_simple_file_system_protocol_guid,
+                                 NULL);
        if (ret == EFI_SUCCESS)
                return efi_load_image_from_file(file_path, buffer, size);
 
-       ret = EFI_CALL(efi_locate_device_path(
-                      &efi_guid_load_file_protocol, &dp, &device));
+       ret = efi_search_protocol(device, &efi_guid_load_file_protocol, NULL);
        if (ret == EFI_SUCCESS) {
                guid = &efi_guid_load_file_protocol;
        } else if (!boot_policy) {
                guid = &efi_guid_load_file2_protocol;
-               ret = EFI_CALL(efi_locate_device_path(guid, &dp, &device));
+               ret = efi_search_protocol(device, guid, NULL);
        }
        if (ret != EFI_SUCCESS)
                return EFI_NOT_FOUND;
@@ -1971,9 +1971,9 @@ efi_status_t efi_load_image_from_path(bool boot_policy,
        if (ret != EFI_SUCCESS)
                return EFI_NOT_FOUND;
        buffer_size = 0;
-       ret = load_file_protocol->load_file(load_file_protocol, dp,
-                                           boot_policy, &buffer_size,
-                                           NULL);
+       ret = EFI_CALL(load_file_protocol->load_file(
+                                       load_file_protocol, rem, boot_policy,
+                                       &buffer_size, NULL));
        if (ret != EFI_BUFFER_TOO_SMALL)
                goto out;
        pages = efi_size_in_pages(buffer_size);
@@ -1984,7 +1984,7 @@ efi_status_t efi_load_image_from_path(bool boot_policy,
                goto out;
        }
        ret = EFI_CALL(load_file_protocol->load_file(
-                                       load_file_protocol, dp, boot_policy,
+                                       load_file_protocol, rem, boot_policy,
                                        &buffer_size, (void *)(uintptr_t)addr));
        if (ret != EFI_SUCCESS)
                efi_free_pages(addr, pages);