lib/efi_loader/efi_bootmgr.c - u-boot-mtk - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  *  EFI boot manager
  *
  *  Copyright (c) 2017 Rob Clark
  */

 #include <common.h>
 #include <charset.h>
 #include <malloc.h>
 #include <efi_loader.h>
 #include <asm/unaligned.h>

 static const struct efi_boot_services *bs;
 static const struct efi_runtime_services *rs;

 /*
  * bootmgr implements the logic of trying to find a payload to boot
  * based on the BootOrder + BootXXXX variables, and then loading it.
  *
  * TODO detecting a special key held (f9?) and displaying a boot menu
  * like you would get on a PC would be clever.
  *
  * TODO if we had a way to write and persist variables after the OS
  * has started, we'd also want to check OsIndications to see if we
  * should do normal or recovery boot.
  */


 /**
  * efi_deserialize_load_option() - parse serialized data
  *
  * Parse serialized data describing a load option and transform it to the
  * efi_load_option structure.
  *
  * @lo:		pointer to target
  * @data:	serialized data
  */
 void efi_deserialize_load_option(struct efi_load_option *lo, u8 *data)
 {
 	lo->attributes = get_unaligned_le32(data);
 	data += sizeof(u32);

 	lo->file_path_length = get_unaligned_le16(data);
 	data += sizeof(u16);

 	/* FIXME */
 	lo->label = (u16 *)data;
 	data += (u16_strlen(lo->label) + 1) * sizeof(u16);

 	/* FIXME */
 	lo->file_path = (struct efi_device_path *)data;
 	data += lo->file_path_length;

 	lo->optional_data = data;
 }

 /**
  * efi_serialize_load_option() - serialize load option
  *
  * Serialize efi_load_option structure into byte stream for BootXXXX.
  *
  * @data:	buffer for serialized data
  * @lo:		load option
  * Return:	size of allocated buffer
  */
 unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data)
 {
 	unsigned long label_len;
 	unsigned long size;
 	u8 *p;

 	label_len = (u16_strlen(lo->label) + 1) * sizeof(u16);

 	/* total size */
 	size = sizeof(lo->attributes);
 	size += sizeof(lo->file_path_length);
 	size += label_len;
 	size += lo->file_path_length;
 	if (lo->optional_data)
 		size += (utf8_utf16_strlen((const char *)lo->optional_data)
 					   + 1) * sizeof(u16);
 	p = malloc(size);
 	if (!p)
 		return 0;

 	/* copy data */
 	*data = p;
 	memcpy(p, &lo->attributes, sizeof(lo->attributes));
 	p += sizeof(lo->attributes);

 	memcpy(p, &lo->file_path_length, sizeof(lo->file_path_length));
 	p += sizeof(lo->file_path_length);

 	memcpy(p, lo->label, label_len);
 	p += label_len;

 	memcpy(p, lo->file_path, lo->file_path_length);
 	p += lo->file_path_length;

 	if (lo->optional_data) {
 		utf8_utf16_strcpy((u16 **)&p, (const char *)lo->optional_data);
 		p += sizeof(u16); /* size of trailing \0 */
 	}
 	return size;
 }

 /**
  * get_var() - get UEFI variable
  *
  * It is the caller's duty to free the returned buffer.
  *
  * @name:	name of variable
  * @vendor:	vendor GUID of variable
  * @size:	size of allocated buffer
  * Return:	buffer with variable data or NULL
  */
 static void *get_var(u16 *name, const efi_guid_t *vendor,
 		     efi_uintn_t *size)
 {
 	efi_guid_t *v = (efi_guid_t *)vendor;
 	efi_status_t ret;
 	void *buf = NULL;

 	*size = 0;
 	EFI_CALL(ret = rs->get_variable(name, v, NULL, size, buf));
 	if (ret == EFI_BUFFER_TOO_SMALL) {
 		buf = malloc(*size);
 		EFI_CALL(ret = rs->get_variable(name, v, NULL, size, buf));
 	}

 	if (ret != EFI_SUCCESS) {
 		free(buf);
 		*size = 0;
 		return NULL;
 	}

 	return buf;
 }

 /**
  * try_load_entry() - try to load image for boot option
  *
  * Attempt to load load-option number 'n', returning device_path and file_path
  * if successful. This checks that the EFI_LOAD_OPTION is active (enabled)
  * and that the specified file to boot exists.
  *
  * @n:		number of the boot option, e.g. 0x0a13 for Boot0A13
  * @handle:	on return handle for the newly installed image
  * Return:	status code
  */
 static efi_status_t try_load_entry(u16 n, efi_handle_t *handle)
 {
 	struct efi_load_option lo;
 	u16 varname[] = L"Boot0000";
 	u16 hexmap[] = L"0123456789ABCDEF";
 	void *load_option;
 	efi_uintn_t size;
 	efi_status_t ret;

 	varname[4] = hexmap[(n & 0xf000) >> 12];
 	varname[5] = hexmap[(n & 0x0f00) >> 8];
 	varname[6] = hexmap[(n & 0x00f0) >> 4];
 	varname[7] = hexmap[(n & 0x000f) >> 0];

 	load_option = get_var(varname, &efi_global_variable_guid, &size);
 	if (!load_option)
 		return EFI_LOAD_ERROR;

 	efi_deserialize_load_option(&lo, load_option);

 	if (lo.attributes & LOAD_OPTION_ACTIVE) {
 		u32 attributes;

 		debug("%s: trying to load \"%ls\" from %pD\n",
 		      __func__, lo.label, lo.file_path);

 		ret = EFI_CALL(efi_load_image(true, efi_root, lo.file_path,
 					      NULL, 0, handle));
 		if (ret != EFI_SUCCESS) {
 			printf("Loading from Boot%04X '%ls' failed\n", n,
 			       lo.label);
 			goto error;
 		}

 		attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
 			     EFI_VARIABLE_RUNTIME_ACCESS;
 		size = sizeof(n);
 		ret = EFI_CALL(efi_set_variable(
 				L"BootCurrent",
 				(efi_guid_t *)&efi_global_variable_guid,
 				attributes, size, &n));
 		if (ret != EFI_SUCCESS) {
 			if (EFI_CALL(efi_unload_image(*handle))
 			    != EFI_SUCCESS)
 				printf("Unloading image failed\n");
 			goto error;
 		}

 		printf("Booting: %ls\n", lo.label);
 	} else {
 		ret = EFI_LOAD_ERROR;
 	}

 error:
 	free(load_option);

 	return ret;
 }

 /**
  * efi_bootmgr_load() - try to load from BootNext or BootOrder
  *
  * Attempt to load from BootNext or in the order specified by BootOrder
  * EFI variable, the available load-options, finding and returning
  * the first one that can be loaded successfully.
  *
  * @handle:	on return handle for the newly installed image
  * Return:	status code
  */
 efi_status_t efi_bootmgr_load(efi_handle_t *handle)
 {
 	u16 bootnext, *bootorder;
 	efi_uintn_t size;
 	int i, num;
 	efi_status_t ret;

 	bs = systab.boottime;
 	rs = systab.runtime;

 	/* BootNext */
 	bootnext = 0;
 	size = sizeof(bootnext);
 	ret = EFI_CALL(efi_get_variable(L"BootNext",
 					(efi_guid_t *)&efi_global_variable_guid,
 					NULL, &size, &bootnext));
 	if (ret == EFI_SUCCESS || ret == EFI_BUFFER_TOO_SMALL) {
 		/* BootNext does exist here */
 		if (ret == EFI_BUFFER_TOO_SMALL || size != sizeof(u16))
 			printf("BootNext must be 16-bit integer\n");

 		/* delete BootNext */
 		ret = EFI_CALL(efi_set_variable(
 					L"BootNext",
 					(efi_guid_t *)&efi_global_variable_guid,
 					EFI_VARIABLE_NON_VOLATILE, 0,
 					&bootnext));

 		/* load BootNext */
 		if (ret == EFI_SUCCESS) {
 			if (size == sizeof(u16)) {
 				ret = try_load_entry(bootnext, handle);
 				if (ret == EFI_SUCCESS)
 					return ret;
 				printf("Loading from BootNext failed, falling back to BootOrder\n");
 			}
 		} else {
 			printf("Deleting BootNext failed\n");
 		}
 	}

 	/* BootOrder */
 	bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size);
 	if (!bootorder) {
 		printf("BootOrder not defined\n");
 		ret = EFI_NOT_FOUND;
 		goto error;
 	}

 	num = size / sizeof(uint16_t);
 	for (i = 0; i < num; i++) {
 		debug("%s: trying to load Boot%04X\n", __func__, bootorder[i]);
 		ret = try_load_entry(bootorder[i], handle);
 		if (ret == EFI_SUCCESS)
 			break;
 	}

 	free(bootorder);

 error:
 	return ret;
 }
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* EFI boot manager
	*
	* Copyright (c) 2017 Rob Clark
	*/

	#include <common.h>
	#include <charset.h>
	#include <malloc.h>
	#include <efi_loader.h>
	#include <asm/unaligned.h>

	static const struct efi_boot_services *bs;
	static const struct efi_runtime_services *rs;

	/*
	* bootmgr implements the logic of trying to find a payload to boot
	* based on the BootOrder + BootXXXX variables, and then loading it.
	*
	* TODO detecting a special key held (f9?) and displaying a boot menu
	* like you would get on a PC would be clever.
	*
	* TODO if we had a way to write and persist variables after the OS
	* has started, we'd also want to check OsIndications to see if we
	* should do normal or recovery boot.
	*/


	/**
	* efi_deserialize_load_option() - parse serialized data
	*
	* Parse serialized data describing a load option and transform it to the
	* efi_load_option structure.
	*
	* @lo: pointer to target
	* @data: serialized data
	*/
	void efi_deserialize_load_option(struct efi_load_option lo, u8 data)
	{
	lo->attributes = get_unaligned_le32(data);
	data += sizeof(u32);

	lo->file_path_length = get_unaligned_le16(data);
	data += sizeof(u16);

	/* FIXME */
	lo->label = (u16 *)data;
	data += (u16_strlen(lo->label) + 1) * sizeof(u16);

	/* FIXME */
	lo->file_path = (struct efi_device_path *)data;
	data += lo->file_path_length;

	lo->optional_data = data;
	}

	/**
	* efi_serialize_load_option() - serialize load option
	*
	* Serialize efi_load_option structure into byte stream for BootXXXX.
	*
	* @data: buffer for serialized data
	* @lo: load option
	* Return: size of allocated buffer
	*/
	unsigned long efi_serialize_load_option(struct efi_load_option lo, u8 *data)
	{
	unsigned long label_len;
	unsigned long size;
	u8 *p;

	label_len = (u16_strlen(lo->label) + 1) * sizeof(u16);

	/* total size */
	size = sizeof(lo->attributes);
	size += sizeof(lo->file_path_length);
	size += label_len;
	size += lo->file_path_length;
	if (lo->optional_data)
	size += (utf8_utf16_strlen((const char *)lo->optional_data)
	+ 1) * sizeof(u16);
	p = malloc(size);
	if (!p)
	return 0;

	/* copy data */
	*data = p;
	memcpy(p, &lo->attributes, sizeof(lo->attributes));
	p += sizeof(lo->attributes);

	memcpy(p, &lo->file_path_length, sizeof(lo->file_path_length));
	p += sizeof(lo->file_path_length);

	memcpy(p, lo->label, label_len);
	p += label_len;

	memcpy(p, lo->file_path, lo->file_path_length);
	p += lo->file_path_length;

	if (lo->optional_data) {
	utf8_utf16_strcpy((u16 *)&p, (const char )lo->optional_data);
	p += sizeof(u16); /* size of trailing \0 */
	}
	return size;
	}

	/**
	* get_var() - get UEFI variable
	*
	* It is the caller's duty to free the returned buffer.
	*
	* @name: name of variable
	* @vendor: vendor GUID of variable
	* @size: size of allocated buffer
	* Return: buffer with variable data or NULL
	*/
	static void get_var(u16 name, const efi_guid_t *vendor,
	efi_uintn_t *size)
	{
	efi_guid_t v = (efi_guid_t )vendor;
	efi_status_t ret;
	void *buf = NULL;

	*size = 0;
	EFI_CALL(ret = rs->get_variable(name, v, NULL, size, buf));
	if (ret == EFI_BUFFER_TOO_SMALL) {
	buf = malloc(*size);
	EFI_CALL(ret = rs->get_variable(name, v, NULL, size, buf));
	}

	if (ret != EFI_SUCCESS) {
	free(buf);
	*size = 0;
	return NULL;
	}

	return buf;
	}

	/**
	* try_load_entry() - try to load image for boot option
	*
	* Attempt to load load-option number 'n', returning device_path and file_path
	* if successful. This checks that the EFI_LOAD_OPTION is active (enabled)
	* and that the specified file to boot exists.
	*
	* @n: number of the boot option, e.g. 0x0a13 for Boot0A13
	* @handle: on return handle for the newly installed image
	* Return: status code
	*/
	static efi_status_t try_load_entry(u16 n, efi_handle_t *handle)
	{
	struct efi_load_option lo;
	u16 varname[] = L"Boot0000";
	u16 hexmap[] = L"0123456789ABCDEF";
	void *load_option;
	efi_uintn_t size;
	efi_status_t ret;

	varname[4] = hexmap[(n & 0xf000) >> 12];
	varname[5] = hexmap[(n & 0x0f00) >> 8];
	varname[6] = hexmap[(n & 0x00f0) >> 4];
	varname[7] = hexmap[(n & 0x000f) >> 0];

	load_option = get_var(varname, &efi_global_variable_guid, &size);
	if (!load_option)
	return EFI_LOAD_ERROR;

	efi_deserialize_load_option(&lo, load_option);

	if (lo.attributes & LOAD_OPTION_ACTIVE) {
	u32 attributes;

	debug("%s: trying to load \"%ls\" from %pD\n",
	__func__, lo.label, lo.file_path);

	ret = EFI_CALL(efi_load_image(true, efi_root, lo.file_path,
	NULL, 0, handle));
	if (ret != EFI_SUCCESS) {
	printf("Loading from Boot%04X '%ls' failed\n", n,
	lo.label);
	goto error;
	}

	attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS \|
	EFI_VARIABLE_RUNTIME_ACCESS;
	size = sizeof(n);
	ret = EFI_CALL(efi_set_variable(
	L"BootCurrent",
	(efi_guid_t *)&efi_global_variable_guid,
	attributes, size, &n));
	if (ret != EFI_SUCCESS) {
	if (EFI_CALL(efi_unload_image(*handle))
	!= EFI_SUCCESS)
	printf("Unloading image failed\n");
	goto error;
	}

	printf("Booting: %ls\n", lo.label);
	} else {
	ret = EFI_LOAD_ERROR;
	}

	error:
	free(load_option);

	return ret;
	}

	/**
	* efi_bootmgr_load() - try to load from BootNext or BootOrder
	*
	* Attempt to load from BootNext or in the order specified by BootOrder
	* EFI variable, the available load-options, finding and returning
	* the first one that can be loaded successfully.
	*
	* @handle: on return handle for the newly installed image
	* Return: status code
	*/
	efi_status_t efi_bootmgr_load(efi_handle_t *handle)
	{
	u16 bootnext, *bootorder;
	efi_uintn_t size;
	int i, num;
	efi_status_t ret;

	bs = systab.boottime;
	rs = systab.runtime;

	/* BootNext */
	bootnext = 0;
	size = sizeof(bootnext);
	ret = EFI_CALL(efi_get_variable(L"BootNext",
	(efi_guid_t *)&efi_global_variable_guid,
	NULL, &size, &bootnext));
	if (ret == EFI_SUCCESS \|\| ret == EFI_BUFFER_TOO_SMALL) {
	/* BootNext does exist here */
	if (ret == EFI_BUFFER_TOO_SMALL \|\| size != sizeof(u16))
	printf("BootNext must be 16-bit integer\n");

	/* delete BootNext */
	ret = EFI_CALL(efi_set_variable(
	L"BootNext",
	(efi_guid_t *)&efi_global_variable_guid,
	EFI_VARIABLE_NON_VOLATILE, 0,
	&bootnext));

	/* load BootNext */
	if (ret == EFI_SUCCESS) {
	if (size == sizeof(u16)) {
	ret = try_load_entry(bootnext, handle);
	if (ret == EFI_SUCCESS)
	return ret;
	printf("Loading from BootNext failed, falling back to BootOrder\n");
	}
	} else {
	printf("Deleting BootNext failed\n");
	}
	}

	/* BootOrder */
	bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size);
	if (!bootorder) {
	printf("BootOrder not defined\n");
	ret = EFI_NOT_FOUND;
	goto error;
	}

	num = size / sizeof(uint16_t);
	for (i = 0; i < num; i++) {
	debug("%s: trying to load Boot%04X\n", __func__, bootorder[i]);
	ret = try_load_entry(bootorder[i], handle);
	if (ret == EFI_SUCCESS)
	break;
	}

	free(bootorder);

	error:
	return ret;
	}