bootmenu: add removable media entries

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>

5 files changed, 245 insertions, 6 deletions

diff --git a/cmd/bootmenu.c b/cmd/bootmenu.c
index 704d36debe..3340be1632 100644
--- a/cmd/bootmenu.c
+++ b/cmd/bootmenu.c
@@ -7,7 +7,7 @@
 #include <common.h>
 #include <command.h>
 #include <ansi.h>
-#include <efi_loader.h>
+#include <efi_config.h>
 #include <efi_variable.h>
 #include <env.h>
 #include <log.h>
@@ -220,7 +220,7 @@ static int prepare_bootmenu_entry(struct bootmenu_data *menu,
 	return 1;
 }
 
-#if (CONFIG_IS_ENABLED(CMD_BOOTEFI_BOOTMGR))
+#if (CONFIG_IS_ENABLED(CMD_BOOTEFI_BOOTMGR)) && (CONFIG_IS_ENABLED(CMD_EFICONFIG))
 /**
  * prepare_uefi_bootorder_entry() - generate the uefi bootmenu entries
  *
@@ -340,11 +340,21 @@ static struct bootmenu_data *bootmenu_create(int delay)
 	if (ret < 0)
 		goto cleanup;
 
-#if (CONFIG_IS_ENABLED(CMD_BOOTEFI_BOOTMGR))
+#if (CONFIG_IS_ENABLED(CMD_BOOTEFI_BOOTMGR)) && (CONFIG_IS_ENABLED(CMD_EFICONFIG))
 	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 = eficonfig_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 5841a3ffe1..bbd6c3229e 100644
--- a/cmd/eficonfig.c
+++ b/cmd/eficonfig.c
@@ -1859,6 +1859,214 @@ static efi_status_t eficonfig_process_delete_boot_option(void *data)
 }
 
 /**
+ * eficonfig_enumerate_boot_option() - enumerate the possible bootable media
+ *
+ * @opt:		pointer to the media boot option structure
+ * @volume_handles:	pointer to the efi handles
+ * @count:		number of efi handle
+ * Return:		status code
+ */
+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++) {
+		u16 *p;
+		u16 dev_name[BOOTMENU_DEVICE_NAME_MAX];
+		char *optional_data;
+		struct efi_load_option lo;
+		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_disk_get_device_name(volume_handles[i], buf, BOOTMENU_DEVICE_NAME_MAX);
+		if (ret != EFI_SUCCESS)
+			continue;
+
+		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;
+			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));
+	}
+
+out:
+	return ret;
+}
+
+/**
+ * eficonfig_delete_invalid_boot_option() - delete non-existing boot option
+ *
+ * @opt:		pointer to the media boot option structure
+ * @count:		number of media boot option structure
+ * Return:		status code
+ */
+efi_status_t eficonfig_delete_invalid_boot_option(struct eficonfig_media_boot_option *opt,
+						  efi_status_t count)
+{
+	u32 i, j;
+	efi_uintn_t size;
+	efi_status_t ret;
+	void *load_option;
+	struct efi_load_option lo;
+	u16 varname[] = u"Boot####";
+
+	for (i = 0; i <= 0xFFFF; i++) {
+		efi_uintn_t tmp;
+
+		efi_create_indexed_name(varname, sizeof(varname), "Boot", i);
+		load_option = efi_get_var(varname, &efi_global_variable_guid, &size);
+		if (!load_option)
+			continue;
+
+		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(i);
+					if (ret != EFI_SUCCESS) {
+						free(load_option);
+						goto out;
+					}
+				}
+			}
+		}
+next:
+		free(load_option);
+	}
+
+out:
+	return ret;
+}
+
+/**
+ * eficonfig_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
+ */
+efi_status_t eficonfig_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) {
+				efi_set_variable_int(var_name, &efi_global_variable_guid,
+						     0, 0, NULL, false);
+				goto out;
+			}
+		}
+	}
+
+out:
+	if (opt) {
+		for (i = 0; i < count; i++)
+			free(opt[i].lo);
+	}
+	free(opt);
+	efi_free_pool(volume_handles);
+
+	return ret;
+}
+
+
+/**
  * eficonfig_init() - do required initialization for eficonfig command
  *
  * Return:	status code
diff --git a/include/efi_config.h b/include/efi_config.h
index dddffe045e..098cac2115 100644
--- a/include/efi_config.h
+++ b/include/efi_config.h
@@ -93,5 +93,6 @@ efi_status_t eficonfig_select_file_handler(void *data);
 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_generate_media_device_boot_option(void);
 
 #endif
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 4461f721e0..6b63ae8dde 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -953,6 +953,22 @@ 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_hash_regions(struct image_region *regs, int count,
 		      void **hash, const char *hash_algo, int *len);
 bool efi_signature_lookup_digest(struct efi_image_regions *regs,
diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c
index ede9116b3c..4b24b41047 100644
--- a/lib/efi_loader/efi_bootmgr.c
+++ b/lib/efi_loader/efi_bootmgr.c
@@ -246,6 +246,10 @@ 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) {