[PATCH v4 10/11] bootmenu: add removable media entries

[Masahisa Kojima <masahisa.kojima@linaro.org>]

UEFI specification requires booting from removal media using
a architecture-specific default image name such as BOOTAA64.EFI.
This commit adds the removable media entries into bootmenu,
so that user can select the removable media and boot with
default image.

The bootmenu automatically enumerates the possible bootable
media devices supporting EFI_SIMPLE_FILE_SYSTEM_PROTOCOL,
add it as new UEFI boot option(BOOT####) and update BootOrder
variable. Depending on the system hardware setup, some devices
may not exist at a later system boot, so invalid BOOT#### variable
must be deleted.

Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
---
Newly created in v4

 cmd/bootmenu.c                            |  78 +++++++++++++
 include/efi_loader.h                      |  22 ++++
 lib/efi_loader/efi_bootmenu_maintenance.c | 128 ++++++++++++++++++++++
 3 files changed, 228 insertions(+)

diff --git a/cmd/bootmenu.c b/cmd/bootmenu.c
index 458eb90b63..7357cfeae5 100644
--- a/cmd/bootmenu.c
+++ b/cmd/bootmenu.c
@@ -304,6 +304,74 @@ static int prepare_uefi_bootorder_entry(struct bootmenu_data *menu,
 	return 1;
 }
 
+static efi_status_t prepare_media_device_entry(void)
+{
+	u32 i;
+	efi_status_t ret;
+	efi_uintn_t count;
+	efi_handle_t *volume_handles = NULL;
+	struct efi_bootmenu_media_boot_option *opt = NULL;
+
+	ret = efi_locate_handle_buffer_int(BY_PROTOCOL, &efi_simple_file_system_protocol_guid,
+					   NULL, &count, (efi_handle_t **)&volume_handles);
+	if (ret != EFI_SUCCESS)
+		return ret;
+
+	opt = calloc(count, sizeof(struct efi_bootmenu_media_boot_option));
+	if (!opt)
+		goto out;
+
+	/* enumerate all devices supporting EFI_SIMPLE_FILE_SYSTEM_PROTOCOL */
+	ret = efi_bootmenu_enumerate_boot_option(opt, volume_handles, count);
+	if (ret != EFI_SUCCESS)
+		goto out;
+
+	/*
+	 * System hardware configuration may vary depending on the user setup.
+	 * The boot option is automatically added by the bootmenu.
+	 * If the device is not attached to the system, the boot option needs
+	 * to be deleted.
+	 */
+	ret = efi_bootmenu_delete_invalid_boot_option(opt, count);
+	if (ret != EFI_SUCCESS)
+		goto out;
+
+	/* add non-existent boot option */
+	for (i = 0; i < count; i++) {
+		u32 boot_index;
+		u16 var_name[9];
+
+		if (!opt[i].exist) {
+			ret = efi_bootmenu_get_unused_bootoption(var_name, sizeof(var_name),
+								 &boot_index);
+			if (ret != EFI_SUCCESS)
+				goto out;
+
+			ret = efi_set_variable_int(var_name, &efi_global_variable_guid,
+						   EFI_VARIABLE_NON_VOLATILE |
+						   EFI_VARIABLE_BOOTSERVICE_ACCESS |
+						   EFI_VARIABLE_RUNTIME_ACCESS,
+						   opt[i].size, opt[i].lo, false);
+			if (ret != EFI_SUCCESS)
+				goto out;
+
+			ret = efi_bootmenu_append_bootorder(boot_index);
+			if (ret != EFI_SUCCESS)
+				goto out;
+		}
+	}
+
+out:
+	if (opt) {
+		for (i = 0; i < count; i++)
+			free(opt[i].lo);
+	}
+	free(opt);
+	efi_free_pool(volume_handles);
+
+	return ret;
+}
+
 static int prepare_distro_boot_entry(struct bootmenu_data *menu,
 				     struct bootmenu_entry **current,
 				     unsigned short int *index)
@@ -408,6 +476,16 @@ static struct bootmenu_data *bootmenu_create(int delay)
 		goto cleanup;
 
 	if (IS_ENABLED(CONFIG_CMD_BOOTEFI_BOOTMGR)) {
+		if (i < MAX_DYNAMIC_ENTRY) {
+			/*
+			 * UEFI specification requires booting from removal media using
+			 * a architecture-specific default image name such as BOOTAA64.EFI.
+			 */
+			ret = prepare_media_device_entry();
+			if (ret != EFI_SUCCESS)
+				goto cleanup;
+		}
+
 		if (i < MAX_DYNAMIC_ENTRY) {
 			ret = prepare_uefi_bootorder_entry(menu, &iter, &i);
 			if (ret < 0 && ret != -ENOENT)
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 7b100ca030..c326dfdaf2 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -926,6 +926,22 @@ struct efi_signature_store {
 struct x509_certificate;
 struct pkcs7_message;
 
+/**
+ * struct efi_bootmenu_media_boot_option - boot option for (removable) media device
+ *
+ * This structure is used to enumerate possible boot option
+ *
+ * @lo:		Serialized load option data
+ * @size:	Size of serialized load option data
+ * @exist:	Flag to indicate the load option already exists
+ *		in Non-volatile load option
+ */
+struct efi_bootmenu_media_boot_option {
+	void *lo;
+	efi_uintn_t size;
+	bool exist;
+};
+
 bool efi_signature_lookup_digest(struct efi_image_regions *regs,
 				 struct efi_signature_store *db,
 				 bool dbx);
@@ -1038,6 +1054,12 @@ efi_status_t efi_console_get_u16_string
 efi_status_t efi_bootmenu_get_unused_bootoption(u16 *buf,
 						efi_uintn_t buf_size, u32 *index);
 efi_status_t efi_bootmenu_append_bootorder(u16 index);
+efi_status_t efi_bootmenu_enumerate_boot_option(
+			struct efi_bootmenu_media_boot_option *opt,
+			efi_handle_t *volume_handles, efi_status_t count);
+efi_status_t efi_bootmenu_delete_invalid_boot_option(
+			struct efi_bootmenu_media_boot_option *opt,
+			efi_status_t count);
 
 efi_status_t efi_disk_get_device_name(struct efi_block_io *this, char *buf, int size);
 
diff --git a/lib/efi_loader/efi_bootmenu_maintenance.c b/lib/efi_loader/efi_bootmenu_maintenance.c
index 2ce5a47b10..3a64cf767a 100644
--- a/lib/efi_loader/efi_bootmenu_maintenance.c
+++ b/lib/efi_loader/efi_bootmenu_maintenance.c
@@ -24,6 +24,8 @@ static struct efi_simple_text_output_protocol *cout;
 #define EFI_BOOTMENU_FILE_PATH_MAX 512
 #define EFI_BOOTMENU_BOOT_NAME_MAX 32
 #define EFI_BOOT_ORDER_MAX_SIZE_IN_DECIMAL 6
+#define BOOTMENU_AUTO_ADD_OPTION_DATA "bootmenu"
+#define BOOTMENU_AUTO_ADD_OPTION_DATA_U16 u"bootmenu"
 
 typedef efi_status_t (*efi_bootmenu_entry_func)(void *data, bool *exit);
 
@@ -1114,3 +1116,129 @@ efi_status_t efi_bootmenu_show_maintenance_menu(void)
 					  ARRAY_SIZE(maintenance_menu_items),
 					  -1);
 }
+
+efi_status_t efi_bootmenu_enumerate_boot_option(
+			struct efi_bootmenu_media_boot_option *opt,
+			efi_handle_t *volume_handles, efi_status_t count)
+{
+	u32 i;
+	struct efi_handler *handler;
+	efi_status_t ret = EFI_SUCCESS;
+
+	for (i = 0; i < count; i++) {
+		u16 *dev_name, *p;
+		struct efi_load_option lo;
+		struct efi_block_io *block_io;
+		char buf[BOOTMENU_DEVICE_NAME_MAX];
+		struct efi_device_path *device_path;
+
+		ret = efi_search_protocol(volume_handles[i], &efi_guid_device_path, &handler);
+		if (ret != EFI_SUCCESS)
+			continue;
+		ret = efi_protocol_open(handler, (void **)&device_path,
+					efi_root, NULL, EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+		if (ret != EFI_SUCCESS)
+			continue;
+
+		ret = efi_search_protocol(volume_handles[i], &efi_block_io_guid, &handler);
+		if (ret != EFI_SUCCESS)
+			continue;
+		ret = efi_protocol_open(handler, (void **)&block_io,
+					efi_root, NULL, EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+		if (ret != EFI_SUCCESS)
+			continue;
+
+		efi_disk_get_device_name(block_io, buf, BOOTMENU_DEVICE_NAME_MAX);
+		dev_name = calloc(1, (strlen(buf) + 1) * sizeof(u16));
+		if (!dev_name) {
+			ret = EFI_OUT_OF_RESOURCES;
+			goto out;
+		}
+		p = dev_name;
+		utf8_utf16_strncpy(&p, buf, strlen(buf));
+
+		lo.label = dev_name;
+		lo.attributes = LOAD_OPTION_ACTIVE;
+		lo.file_path = device_path;
+		lo.file_path_length = efi_dp_size(device_path) + sizeof(END);
+		/*
+		 * To identify the boot option that automatically added by
+		 * the bootmenu, optional_data has special string.
+		 * optional_data will be converted into u16 string
+		 * in efi_serialize_load_option().
+		 */
+		lo.optional_data = BOOTMENU_AUTO_ADD_OPTION_DATA;
+		opt[i].size = efi_serialize_load_option(&lo, (u8 **)&opt[i].lo);
+		if (!opt[i].size) {
+			ret = EFI_OUT_OF_RESOURCES;
+			free(dev_name);
+			goto out;
+		}
+		free(dev_name);
+	}
+
+out:
+	return ret;
+}
+
+efi_status_t efi_bootmenu_delete_invalid_boot_option(
+			struct efi_bootmenu_media_boot_option *opt,
+			efi_status_t count)
+{
+	u16 *bootorder;
+	u32 i, j;
+	efi_status_t ret;
+	efi_uintn_t num, size, bootorder_size;
+	void *load_option;
+	struct efi_load_option lo;
+	u16 varname[] = u"Boot####";
+
+	bootorder = efi_get_var(u"BootOrder", &efi_global_variable_guid, &bootorder_size);
+	if (!bootorder)
+		return EFI_NOT_FOUND;
+
+	num = bootorder_size / sizeof(u16);
+	for (i = 0; i < num;) {
+		efi_uintn_t tmp;
+
+		efi_create_indexed_name(varname, sizeof(varname),
+					"Boot", bootorder[i]);
+		load_option = efi_get_var(varname, &efi_global_variable_guid, &size);
+		if (!load_option)
+			goto next;
+
+		tmp = size;
+		ret = efi_deserialize_load_option(&lo, load_option, &tmp);
+		if (ret != EFI_SUCCESS)
+			goto next;
+
+		if (u16_strncmp((u16 *)lo.optional_data, BOOTMENU_AUTO_ADD_OPTION_DATA_U16,
+				u16_strlen(BOOTMENU_AUTO_ADD_OPTION_DATA_U16)) == 0) {
+			for (j = 0; j < count; j++) {
+				if (memcmp(opt[j].lo, load_option, size) == 0) {
+					opt[j].exist = true;
+					break;
+				}
+			}
+
+			if (j == count) {
+				ret = delete_boot_option(bootorder, i, bootorder_size);
+				if (ret != EFI_SUCCESS) {
+					free(load_option);
+					goto out;
+				}
+
+				num--;
+				bootorder_size -= sizeof(u16);
+				free(load_option);
+				continue;
+			}
+		}
+next:
+		free(load_option);
+		i++;
+	}
+
+out:
+	return ret;
+}
-- 
2.17.1