mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-08-18 07:58:52 +09:00
![Heinrich Schuchardt](/assets/img/avatar_default.png)
Bootxxxx variables are provided by the user and therefore cannot be trusted. We have to validate them before usage. A device path provided by a Bootxxxx variable must have an end node within the indicated device path length. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
360 lines
8.8 KiB
C
360 lines
8.8 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* EFI boot manager
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*
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* Copyright (c) 2017 Rob Clark
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*/
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#define LOG_CATEGORY LOGC_EFI
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#include <common.h>
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#include <charset.h>
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#include <log.h>
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#include <malloc.h>
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#include <efi_loader.h>
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#include <efi_variable.h>
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#include <asm/unaligned.h>
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static const struct efi_boot_services *bs;
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static const struct efi_runtime_services *rs;
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/*
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* bootmgr implements the logic of trying to find a payload to boot
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* based on the BootOrder + BootXXXX variables, and then loading it.
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*
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* TODO detecting a special key held (f9?) and displaying a boot menu
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* like you would get on a PC would be clever.
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*
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* TODO if we had a way to write and persist variables after the OS
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* has started, we'd also want to check OsIndications to see if we
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* should do normal or recovery boot.
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*/
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/**
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* efi_set_load_options() - set the load options of a loaded image
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*
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* @handle: the image handle
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* @load_options_size: size of load options
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* @load_options: pointer to load options
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* Return: status code
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*/
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efi_status_t efi_set_load_options(efi_handle_t handle,
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efi_uintn_t load_options_size,
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void *load_options)
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{
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struct efi_loaded_image *loaded_image_info;
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efi_status_t ret;
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ret = EFI_CALL(systab.boottime->open_protocol(
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handle,
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&efi_guid_loaded_image,
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(void **)&loaded_image_info,
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efi_root, NULL,
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EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL));
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if (ret != EFI_SUCCESS)
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return EFI_INVALID_PARAMETER;
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loaded_image_info->load_options = load_options;
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loaded_image_info->load_options_size = load_options_size;
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return EFI_CALL(systab.boottime->close_protocol(handle,
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&efi_guid_loaded_image,
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efi_root, NULL));
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}
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/**
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* efi_deserialize_load_option() - parse serialized data
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*
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* Parse serialized data describing a load option and transform it to the
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* efi_load_option structure.
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*
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* @lo: pointer to target
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* @data: serialized data
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* @size: size of the load option, on return size of the optional data
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* Return: status code
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*/
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efi_status_t efi_deserialize_load_option(struct efi_load_option *lo, u8 *data,
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efi_uintn_t *size)
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{
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efi_uintn_t len;
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len = sizeof(u32);
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if (*size < len + 2 * sizeof(u16))
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return EFI_INVALID_PARAMETER;
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lo->attributes = get_unaligned_le32(data);
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data += len;
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*size -= len;
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len = sizeof(u16);
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lo->file_path_length = get_unaligned_le16(data);
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data += len;
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*size -= len;
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lo->label = (u16 *)data;
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len = u16_strnlen(lo->label, *size / sizeof(u16) - 1);
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if (lo->label[len])
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return EFI_INVALID_PARAMETER;
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len = (len + 1) * sizeof(u16);
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if (*size < len)
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return EFI_INVALID_PARAMETER;
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data += len;
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*size -= len;
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len = lo->file_path_length;
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if (*size < len)
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return EFI_INVALID_PARAMETER;
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lo->file_path = (struct efi_device_path *)data;
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if (efi_dp_check_length(lo->file_path, len) < 0)
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return EFI_INVALID_PARAMETER;
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data += len;
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*size -= len;
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lo->optional_data = data;
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return EFI_SUCCESS;
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}
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/**
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* efi_serialize_load_option() - serialize load option
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*
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* Serialize efi_load_option structure into byte stream for BootXXXX.
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*
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* @data: buffer for serialized data
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* @lo: load option
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* Return: size of allocated buffer
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*/
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unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data)
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{
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unsigned long label_len;
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unsigned long size;
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u8 *p;
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label_len = (u16_strlen(lo->label) + 1) * sizeof(u16);
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/* total size */
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size = sizeof(lo->attributes);
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size += sizeof(lo->file_path_length);
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size += label_len;
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size += lo->file_path_length;
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if (lo->optional_data)
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size += (utf8_utf16_strlen((const char *)lo->optional_data)
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+ 1) * sizeof(u16);
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p = malloc(size);
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if (!p)
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return 0;
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/* copy data */
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*data = p;
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memcpy(p, &lo->attributes, sizeof(lo->attributes));
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p += sizeof(lo->attributes);
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memcpy(p, &lo->file_path_length, sizeof(lo->file_path_length));
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p += sizeof(lo->file_path_length);
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memcpy(p, lo->label, label_len);
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p += label_len;
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memcpy(p, lo->file_path, lo->file_path_length);
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p += lo->file_path_length;
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if (lo->optional_data) {
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utf8_utf16_strcpy((u16 **)&p, (const char *)lo->optional_data);
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p += sizeof(u16); /* size of trailing \0 */
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}
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return size;
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}
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/**
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* get_var() - get UEFI variable
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*
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* It is the caller's duty to free the returned buffer.
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*
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* @name: name of variable
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* @vendor: vendor GUID of variable
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* @size: size of allocated buffer
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* Return: buffer with variable data or NULL
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*/
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static void *get_var(u16 *name, const efi_guid_t *vendor,
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efi_uintn_t *size)
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{
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efi_status_t ret;
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void *buf = NULL;
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*size = 0;
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ret = efi_get_variable_int(name, vendor, NULL, size, buf, NULL);
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if (ret == EFI_BUFFER_TOO_SMALL) {
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buf = malloc(*size);
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ret = efi_get_variable_int(name, vendor, NULL, size, buf, NULL);
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}
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if (ret != EFI_SUCCESS) {
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free(buf);
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*size = 0;
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return NULL;
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}
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return buf;
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}
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/**
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* try_load_entry() - try to load image for boot option
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*
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* Attempt to load load-option number 'n', returning device_path and file_path
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* if successful. This checks that the EFI_LOAD_OPTION is active (enabled)
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* and that the specified file to boot exists.
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*
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* @n: number of the boot option, e.g. 0x0a13 for Boot0A13
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* @handle: on return handle for the newly installed image
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* @load_options: load options set on the loaded image protocol
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* Return: status code
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*/
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static efi_status_t try_load_entry(u16 n, efi_handle_t *handle,
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void **load_options)
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{
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struct efi_load_option lo;
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u16 varname[] = L"Boot0000";
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u16 hexmap[] = L"0123456789ABCDEF";
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void *load_option;
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efi_uintn_t size;
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efi_status_t ret;
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varname[4] = hexmap[(n & 0xf000) >> 12];
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varname[5] = hexmap[(n & 0x0f00) >> 8];
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varname[6] = hexmap[(n & 0x00f0) >> 4];
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varname[7] = hexmap[(n & 0x000f) >> 0];
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load_option = get_var(varname, &efi_global_variable_guid, &size);
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if (!load_option)
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return EFI_LOAD_ERROR;
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ret = efi_deserialize_load_option(&lo, load_option, &size);
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if (ret != EFI_SUCCESS) {
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log_warning("Invalid load option for %ls\n", varname);
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goto error;
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}
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if (lo.attributes & LOAD_OPTION_ACTIVE) {
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u32 attributes;
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log_debug("%s: trying to load \"%ls\" from %pD\n",
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__func__, lo.label, lo.file_path);
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ret = EFI_CALL(efi_load_image(true, efi_root, lo.file_path,
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NULL, 0, handle));
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if (ret != EFI_SUCCESS) {
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log_warning("Loading %ls '%ls' failed\n",
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varname, lo.label);
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goto error;
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}
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attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
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EFI_VARIABLE_RUNTIME_ACCESS;
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ret = efi_set_variable_int(L"BootCurrent",
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&efi_global_variable_guid,
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attributes, sizeof(n), &n, false);
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if (ret != EFI_SUCCESS) {
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if (EFI_CALL(efi_unload_image(*handle))
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!= EFI_SUCCESS)
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log_err("Unloading image failed\n");
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goto error;
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}
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log_info("Booting: %ls\n", lo.label);
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} else {
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ret = EFI_LOAD_ERROR;
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}
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/* Set load options */
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if (size) {
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*load_options = malloc(size);
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if (!*load_options) {
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ret = EFI_OUT_OF_RESOURCES;
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goto error;
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}
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memcpy(*load_options, lo.optional_data, size);
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ret = efi_set_load_options(*handle, size, *load_options);
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} else {
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load_options = NULL;
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}
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error:
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free(load_option);
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return ret;
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}
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/**
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* efi_bootmgr_load() - try to load from BootNext or BootOrder
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*
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* Attempt to load from BootNext or in the order specified by BootOrder
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* EFI variable, the available load-options, finding and returning
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* the first one that can be loaded successfully.
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*
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* @handle: on return handle for the newly installed image
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* @load_options: load options set on the loaded image protocol
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* Return: status code
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*/
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efi_status_t efi_bootmgr_load(efi_handle_t *handle, void **load_options)
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{
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u16 bootnext, *bootorder;
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efi_uintn_t size;
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int i, num;
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efi_status_t ret;
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bs = systab.boottime;
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rs = systab.runtime;
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/* BootNext */
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size = sizeof(bootnext);
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ret = efi_get_variable_int(L"BootNext",
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&efi_global_variable_guid,
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NULL, &size, &bootnext, NULL);
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if (ret == EFI_SUCCESS || ret == EFI_BUFFER_TOO_SMALL) {
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/* BootNext does exist here */
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if (ret == EFI_BUFFER_TOO_SMALL || size != sizeof(u16))
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log_err("BootNext must be 16-bit integer\n");
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/* delete BootNext */
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ret = efi_set_variable_int(L"BootNext",
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&efi_global_variable_guid,
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0, 0, NULL, false);
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/* load BootNext */
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if (ret == EFI_SUCCESS) {
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if (size == sizeof(u16)) {
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ret = try_load_entry(bootnext, handle,
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load_options);
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if (ret == EFI_SUCCESS)
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return ret;
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log_warning(
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"Loading from BootNext failed, falling back to BootOrder\n");
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}
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} else {
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log_err("Deleting BootNext failed\n");
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}
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}
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/* BootOrder */
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bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size);
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if (!bootorder) {
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log_info("BootOrder not defined\n");
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ret = EFI_NOT_FOUND;
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goto error;
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}
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num = size / sizeof(uint16_t);
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for (i = 0; i < num; i++) {
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log_debug("%s trying to load Boot%04X\n", __func__,
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bootorder[i]);
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ret = try_load_entry(bootorder[i], handle, load_options);
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if (ret == EFI_SUCCESS)
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break;
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}
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free(bootorder);
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error:
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return ret;
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}
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