[PATCH v8 7/9] 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. This automatically generated UEFI boot option
has the dedicated guid in the optional_data to distinguish it from
the UEFI boot option user adds manually. This optional_data is
removed when the efi bootmgr loads the selected UEFI boot option.

This commit also provides the BOOT#### variable maintenance feature.
Depending on the system hardware setup, some devices
may not exist at a later system boot, so bootmenu checks the
available device in each bootmenu invocation and automatically
removes the BOOT#### variable corrensponding to the non-existent
media device.

Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
---
Changes in v8:
- function and structure prefix is changed to "eficonfig"

Changes in v7:
- rename prepare_media_device_entry() to generate_media_device_boot_option()

Changes in v6:
- optional_data size is changed to 16bytes
- check the load option size before comparison
- remove guid included in optional_data of auto generated
  entry when loading

Changes in v5:
- Return EFI_SUCCESS if there is no BootOrder defined
- correctly handle the case if no removable device found
- use guid to identify the automatically generated entry by bootmenu

 cmd/bootmenu.c               |  99 +++++++++++++++++++++++++-
 cmd/eficonfig.c              | 131 +++++++++++++++++++++++++++++++++++
 include/efi_loader.h         |  20 ++++++
 lib/efi_loader/efi_bootmgr.c |   4 ++
 4 files changed, 251 insertions(+), 3 deletions(-)

diff --git a/cmd/bootmenu.c b/cmd/bootmenu.c
index 704d36debe..3b4294f7c5 100644
--- a/cmd/bootmenu.c
+++ b/cmd/bootmenu.c
@@ -221,6 +221,89 @@ static int prepare_bootmenu_entry(struct bootmenu_data *menu,
 }
 
 #if (CONFIG_IS_ENABLED(CMD_BOOTEFI_BOOTMGR))
+/**
+ * generate_media_device_boot_option() - generate the media device boot option
+ *
+ * This function enumerates all devices supporting EFI_SIMPLE_FILE_SYSTEM_PROTOCOL
+ * and generate the bootmenu entries.
+ * This function also provide the BOOT#### variable maintenance for
+ * the media device entries.
+ *   - Automatically create the BOOT#### variable for the newly detected device,
+ *     this BOOT#### variable is distinguished by the special GUID
+ *     stored in the EFI_LOAD_OPTION.optional_data
+ *   - If the device is not attached to the system, the associated BOOT#### variable
+ *     is automatically deleted.
+ *
+ * Return:	status code
+ */
+static efi_status_t generate_media_device_boot_option(void)
+{
+	u32 i;
+	efi_status_t ret;
+	efi_uintn_t count;
+	efi_handle_t *volume_handles = NULL;
+	struct eficonfig_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 eficonfig_media_boot_option));
+	if (!opt)
+		goto out;
+
+	/* enumerate all devices supporting EFI_SIMPLE_FILE_SYSTEM_PROTOCOL */
+	ret = eficonfig_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 = eficonfig_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 = eficonfig_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 = eficonfig_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;
+}
+
 /**
  * prepare_uefi_bootorder_entry() - generate the uefi bootmenu entries
  *
@@ -342,9 +425,19 @@ static struct bootmenu_data *bootmenu_create(int delay)
 
 #if (CONFIG_IS_ENABLED(CMD_BOOTEFI_BOOTMGR))
 	if (i < MAX_COUNT - 1) {
-			ret = prepare_uefi_bootorder_entry(menu, &iter, &i);
-			if (ret < 0 && ret != -ENOENT)
-				goto cleanup;
+		efi_status_t efi_ret;
+
+		/*
+		 * UEFI specification requires booting from removal media using
+		 * a architecture-specific default image name such as BOOTAA64.EFI.
+		 */
+		efi_ret = generate_media_device_boot_option();
+		if (efi_ret != EFI_SUCCESS && efi_ret != EFI_NOT_FOUND)
+			goto cleanup;
+
+		ret = prepare_uefi_bootorder_entry(menu, &iter, &i);
+		if (ret < 0 && ret != -ENOENT)
+			goto cleanup;
 	}
 #endif
 
diff --git a/cmd/eficonfig.c b/cmd/eficonfig.c
index c87b04cc87..e62f5e41a4 100644
--- a/cmd/eficonfig.c
+++ b/cmd/eficonfig.c
@@ -1665,6 +1665,137 @@ static efi_status_t eficonfig_process_delete_boot_option(void *data)
 	return ret;
 }
 
+efi_status_t eficonfig_enumerate_boot_option(struct eficonfig_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++) {
+		char *optional_data;
+		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);
+		/*
+		 * Set the dedicated guid to optional_data, it is used to identify
+		 * the boot option that automatically generated by the bootmenu.
+		 * efi_serialize_load_option() expects optional_data is null-terminated
+		 * utf8 string, so set the "1234567" string to allocate enough space
+		 * to store guid, instead of realloc the load_option.
+		 */
+		lo.optional_data = "1234567";
+		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;
+		}
+		/* set the guid */
+		optional_data = (char *)opt[i].lo + (opt[i].size - u16_strsize(u"1234567"));
+		memcpy(optional_data, &efi_guid_bootmenu_auto_generated, sizeof(efi_guid_t));
+		free(dev_name);
+	}
+
+out:
+	return ret;
+}
+
+efi_status_t eficonfig_delete_invalid_boot_option(struct eficonfig_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_SUCCESS; /* BootOrder is not defined, nothing to do */
+
+	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, &size);
+		if (ret != EFI_SUCCESS)
+			goto next;
+
+		if (size >= sizeof(efi_guid_bootmenu_auto_generated)) {
+			if (guidcmp(lo.optional_data, &efi_guid_bootmenu_auto_generated) == 0) {
+				for (j = 0; j < count; j++) {
+					if (opt[j].size == tmp &&
+					    memcmp(opt[j].lo, load_option, tmp) == 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;
+}
+
 static efi_status_t eficonfig_init(void)
 {
 	efi_status_t ret;
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 365ce9493e..9909c58f0b 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -943,6 +943,22 @@ struct efi_signature_store {
 struct x509_certificate;
 struct pkcs7_message;
 
+/**
+ * struct eficonfig_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 eficonfig_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);
@@ -1091,6 +1107,10 @@ efi_status_t efi_console_get_u16_string
 efi_status_t eficonfig_get_unused_bootoption(u16 *buf,
 					     efi_uintn_t buf_size, u32 *index);
 efi_status_t eficonfig_append_bootorder(u16 index);
+efi_status_t eficonfig_enumerate_boot_option(struct eficonfig_media_boot_option *opt,
+					     efi_handle_t *volume_handles, efi_status_t count);
+efi_status_t eficonfig_delete_invalid_boot_option(struct eficonfig_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_bootmgr.c b/lib/efi_loader/efi_bootmgr.c
index 93f6590530..224571957c 100644
--- a/lib/efi_loader/efi_bootmgr.c
+++ b/lib/efi_loader/efi_bootmgr.c
@@ -245,6 +245,10 @@ static efi_status_t try_load_entry(u16 n, efi_handle_t *handle,
 	}
 
 	/* Set load options */
+	if (size >= sizeof(efi_guid_t) &&
+	    !guidcmp(lo.optional_data, &efi_guid_bootmenu_auto_generated))
+		size = 0;
+
 	if (size) {
 		*load_options = malloc(size);
 		if (!*load_options) {
-- 
2.17.1