diff --git a/include/efi_loader.h b/include/efi_loader.h index 5d534e69bb..9c227005d1 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -558,6 +558,11 @@ struct efi_simple_file_system_protocol *efi_simple_file_system( /* open file from device-path: */ struct efi_file_handle *efi_file_from_path(struct efi_device_path *fp); +efi_status_t efi_file_size(struct efi_file_handle *fh, efi_uintn_t *size); + +/* get a device path from a Boot#### option */ +struct efi_device_path *efi_get_dp_from_boot(const efi_guid_t guid); + /** * efi_size_in_pages() - convert size in bytes to size in pages * @@ -723,6 +728,8 @@ efi_status_t EFIAPI efi_query_variable_info( u64 *remaining_variable_storage_size, u64 *maximum_variable_size); +void *efi_get_var(u16 *name, const efi_guid_t *vendor, efi_uintn_t *size); + /* * See section 3.1.3 in the v2.7 UEFI spec for more details on * the layout of EFI_LOAD_OPTION. In short it is: diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile index 10b42e8847..da2741adec 100644 --- a/lib/efi_loader/Makefile +++ b/lib/efi_loader/Makefile @@ -23,6 +23,7 @@ endif obj-$(CONFIG_CMD_BOOTEFI_HELLO) += helloworld_efi.o obj-$(CONFIG_CMD_BOOTEFI_BOOTMGR) += efi_bootmgr.o obj-y += efi_boottime.o +obj-y += efi_helper.o obj-$(CONFIG_EFI_HAVE_CAPSULE_SUPPORT) += efi_capsule.o obj-$(CONFIG_EFI_CAPSULE_FIRMWARE) += efi_firmware.o obj-y += efi_console.o diff --git a/lib/efi_loader/efi_file.c b/lib/efi_loader/efi_file.c index 8ece8e71ee..204105e25a 100644 --- a/lib/efi_loader/efi_file.c +++ b/lib/efi_loader/efi_file.c @@ -409,6 +409,45 @@ static efi_status_t efi_get_file_size(struct file_handle *fh, return EFI_SUCCESS; } +/** + * efi_file_size() - Get the size of a file using an EFI file handle + * + * @fh: EFI file handle + * @size: buffer to fill in the discovered size + * + * Return: size of the file + */ +efi_status_t efi_file_size(struct efi_file_handle *fh, efi_uintn_t *size) +{ + struct efi_file_info *info = NULL; + efi_uintn_t bs = 0; + efi_status_t ret; + + *size = 0; + ret = EFI_CALL(fh->getinfo(fh, (efi_guid_t *)&efi_file_info_guid, &bs, + info)); + if (ret != EFI_BUFFER_TOO_SMALL) { + ret = EFI_DEVICE_ERROR; + goto out; + } + + info = malloc(bs); + if (!info) { + ret = EFI_OUT_OF_RESOURCES; + goto out; + } + ret = EFI_CALL(fh->getinfo(fh, (efi_guid_t *)&efi_file_info_guid, &bs, + info)); + if (ret != EFI_SUCCESS) + goto out; + + *size = info->file_size; + +out: + free(info); + return ret; +} + static efi_status_t file_read(struct file_handle *fh, u64 *buffer_size, void *buffer) { diff --git a/lib/efi_loader/efi_helper.c b/lib/efi_loader/efi_helper.c new file mode 100644 index 0000000000..d03a736461 --- /dev/null +++ b/lib/efi_loader/efi_helper.c @@ -0,0 +1,98 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (c) 2020, Linaro Limited + */ + +#define LOG_CATEGORY LOGC_EFI +#include +#include +#include +#include +#include +#include +#include +#include + +/** + * efi_create_current_boot_var() - Return Boot#### name were #### is replaced by + * the value of BootCurrent + * + * @var_name: variable name + * @var_name_size: size of var_name + * + * Return: Status code + */ +static efi_status_t efi_create_current_boot_var(u16 var_name[], + size_t var_name_size) +{ + efi_uintn_t boot_current_size; + efi_status_t ret; + u16 boot_current; + u16 *pos; + + boot_current_size = sizeof(boot_current); + ret = efi_get_variable_int(L"BootCurrent", + &efi_global_variable_guid, NULL, + &boot_current_size, &boot_current, NULL); + if (ret != EFI_SUCCESS) + goto out; + + pos = efi_create_indexed_name(var_name, var_name_size, "Boot", + boot_current); + if (!pos) { + ret = EFI_OUT_OF_RESOURCES; + goto out; + } + +out: + return ret; +} + +/** + * efi_get_dp_from_boot() - Retrieve and return a device path from an EFI + * Boot### variable. + * A boot option may contain an array of device paths. + * We use a VenMedia() with a specific GUID to identify + * the usage of the array members. This function is + * used to extract a specific device path + * + * @guid: vendor GUID of the VenMedia() device path node identifying the + * device path + * + * Return: device path or NULL. Caller must free the returned value + */ +struct efi_device_path *efi_get_dp_from_boot(const efi_guid_t guid) +{ + struct efi_device_path *file_path = NULL; + struct efi_device_path *tmp = NULL; + struct efi_load_option lo; + void *var_value = NULL; + efi_uintn_t size; + efi_status_t ret; + u16 var_name[16]; + + ret = efi_create_current_boot_var(var_name, sizeof(var_name)); + if (ret != EFI_SUCCESS) + return NULL; + + var_value = efi_get_var(var_name, &efi_global_variable_guid, &size); + if (!var_value) + return NULL; + + ret = efi_deserialize_load_option(&lo, var_value, &size); + if (ret != EFI_SUCCESS) + goto out; + + tmp = efi_dp_from_lo(&lo, &size, guid); + if (!tmp) + goto out; + + /* efi_dp_dup will just return NULL if efi_dp_next is NULL */ + file_path = efi_dp_dup(efi_dp_next(tmp)); + +out: + efi_free_pool(tmp); + free(var_value); + + return file_path; +} diff --git a/lib/efi_loader/efi_var_common.c b/lib/efi_loader/efi_var_common.c index 1c7459266a..b11ed91a74 100644 --- a/lib/efi_loader/efi_var_common.c +++ b/lib/efi_loader/efi_var_common.c @@ -9,6 +9,7 @@ #include #include #include +#include enum efi_secure_mode { EFI_MODE_SETUP, @@ -343,3 +344,35 @@ enum efi_auth_var_type efi_auth_var_get_type(u16 *name, const efi_guid_t *guid) } return EFI_AUTH_VAR_NONE; } + +/** + * efi_get_var() - read value of an EFI variable + * + * @name: variable name + * @start: vendor GUID + * @size: size of allocated buffer + * + * Return: buffer with variable data or NULL + */ +void *efi_get_var(u16 *name, const efi_guid_t *vendor, efi_uintn_t *size) +{ + efi_status_t ret; + void *buf = NULL; + + *size = 0; + ret = efi_get_variable_int(name, vendor, NULL, size, buf, NULL); + if (ret == EFI_BUFFER_TOO_SMALL) { + buf = malloc(*size); + if (!buf) + return NULL; + ret = efi_get_variable_int(name, vendor, NULL, size, buf, NULL); + } + + if (ret != EFI_SUCCESS) { + free(buf); + *size = 0; + return NULL; + } + + return buf; +}