1 // SPDX-License-Identifier: GPL-2.0+
5 * Copyright (c) 2017 Rob Clark
10 #include <efi_loader.h>
12 #include <environment.h>
16 #define READ_ONLY BIT(31)
19 * Mapping between EFI variables and u-boot variables:
21 * efi_$guid_$varname = {attributes}(type)value
25 * efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_OsIndicationsSupported=
26 * "{ro,boot,run}(blob)0000000000000000"
27 * efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_BootOrder=
30 * The attributes are a comma separated list of these possible
34 * + boot - boot-services access
35 * + run - runtime access
37 * NOTE: with current implementation, no variables are available after
38 * ExitBootServices, and all are persisted (if possible).
40 * If not specified, the attributes default to "{boot}".
42 * The required type is one of:
44 * + utf8 - raw utf8 string
45 * + blob - arbitrary length hex string
47 * Maybe a utf16 type would be useful to for a string value to be auto
51 #define PREFIX_LEN (strlen("efi_xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx_"))
54 * efi_to_native() - convert the UEFI variable name and vendor GUID to U-Boot
57 * The U-Boot variable name is a concatenation of prefix 'efi', the hexstring
58 * encoded vendor GUID, and the UTF-8 encoded UEFI variable name separated by
59 * underscores, e.g. 'efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_BootOrder'.
61 * @native: pointer to pointer to U-Boot variable name
62 * @variable_name: UEFI variable name
63 * @vendor: vendor GUID
66 static efi_status_t efi_to_native(char **native, const u16 *variable_name,
67 const efi_guid_t *vendor)
72 len = PREFIX_LEN + utf16_utf8_strlen(variable_name) + 1;
73 *native = malloc(len);
75 return EFI_OUT_OF_RESOURCES;
78 pos += sprintf(pos, "efi_%pUl_", vendor);
79 utf16_utf8_strcpy(&pos, variable_name);
85 * prefix() - skip over prefix
87 * Skip over a prefix string.
89 * @str: string with prefix
90 * @prefix: prefix string
91 * Return: string without prefix, or NULL if prefix not found
93 static const char *prefix(const char *str, const char *prefix)
95 size_t n = strlen(prefix);
96 if (!strncmp(prefix, str, n))
102 * parse_attr() - decode attributes part of variable value
104 * Convert the string encoded attributes of a UEFI variable to a bit mask.
105 * TODO: Several attributes are not supported.
107 * @str: value of U-Boot variable
108 * @attrp: pointer to UEFI attributes
109 * Return: pointer to remainder of U-Boot variable value
111 static const char *parse_attr(const char *str, u32 *attrp)
117 *attrp = EFI_VARIABLE_BOOTSERVICE_ACCESS;
121 while (*str == sep) {
126 if ((s = prefix(str, "ro"))) {
128 } else if ((s = prefix(str, "nv"))) {
129 attr |= EFI_VARIABLE_NON_VOLATILE;
130 } else if ((s = prefix(str, "boot"))) {
131 attr |= EFI_VARIABLE_BOOTSERVICE_ACCESS;
132 } else if ((s = prefix(str, "run"))) {
133 attr |= EFI_VARIABLE_RUNTIME_ACCESS;
135 printf("invalid attribute: %s\n", str);
151 * efi_get_variable() - retrieve value of a UEFI variable
153 * This function implements the GetVariable runtime service.
155 * See the Unified Extensible Firmware Interface (UEFI) specification for
158 * @variable_name: name of the variable
159 * @vendor: vendor GUID
160 * @attributes: attributes of the variable
161 * @data_size: size of the buffer to which the variable value is copied
162 * @data: buffer to which the variable value is copied
163 * Return: status code
165 efi_status_t EFIAPI efi_get_variable(u16 *variable_name,
166 const efi_guid_t *vendor, u32 *attributes,
167 efi_uintn_t *data_size, void *data)
171 unsigned long in_size;
175 EFI_ENTRY("\"%ls\" %pUl %p %p %p", variable_name, vendor, attributes,
178 if (!variable_name || !vendor || !data_size)
179 return EFI_EXIT(EFI_INVALID_PARAMETER);
181 ret = efi_to_native(&native_name, variable_name, vendor);
183 return EFI_EXIT(ret);
185 EFI_PRINT("get '%s'\n", native_name);
187 val = env_get(native_name);
190 return EFI_EXIT(EFI_NOT_FOUND);
192 val = parse_attr(val, &attr);
194 in_size = *data_size;
196 if ((s = prefix(val, "(blob)"))) {
197 size_t len = strlen(s);
199 /* number of hexadecimal digits must be even */
201 return EFI_EXIT(EFI_DEVICE_ERROR);
203 /* two characters per byte: */
208 ret = EFI_BUFFER_TOO_SMALL;
213 return EFI_EXIT(EFI_INVALID_PARAMETER);
215 if (hex2bin(data, s, len))
216 return EFI_EXIT(EFI_DEVICE_ERROR);
218 EFI_PRINT("got value: \"%s\"\n", s);
219 } else if ((s = prefix(val, "(utf8)"))) {
220 unsigned len = strlen(s) + 1;
225 ret = EFI_BUFFER_TOO_SMALL;
230 return EFI_EXIT(EFI_INVALID_PARAMETER);
232 memcpy(data, s, len);
233 ((char *)data)[len] = '\0';
235 EFI_PRINT("got value: \"%s\"\n", (char *)data);
237 EFI_PRINT("invalid value: '%s'\n", val);
238 return EFI_EXIT(EFI_DEVICE_ERROR);
243 *attributes = attr & EFI_VARIABLE_MASK;
245 return EFI_EXIT(ret);
248 static char *efi_variables_list;
249 static char *efi_cur_variable;
252 * parse_uboot_variable() - parse a u-boot variable and get uefi-related
254 * @variable: whole data of u-boot variable (ie. name=value)
255 * @variable_name_size: size of variable_name buffer in byte
256 * @variable_name: name of uefi variable in u16, null-terminated
257 * @vendor: vendor's guid
258 * @attributes: attributes
260 * A uefi variable is encoded into a u-boot variable as described above.
261 * This function parses such a u-boot variable and retrieve uefi-related
262 * information into respective parameters. In return, variable_name_size
263 * is the size of variable name including NULL.
265 * Return: EFI_SUCCESS if parsing is OK, EFI_NOT_FOUND when
266 * the entire variable list has been returned,
267 * otherwise non-zero status code
269 static efi_status_t parse_uboot_variable(char *variable,
270 efi_uintn_t *variable_name_size,
272 const efi_guid_t *vendor,
275 char *guid, *name, *end, c;
276 unsigned long name_len;
279 guid = strchr(variable, '_');
281 return EFI_INVALID_PARAMETER;
283 name = strchr(guid, '_');
285 return EFI_INVALID_PARAMETER;
287 end = strchr(name, '=');
289 return EFI_INVALID_PARAMETER;
291 name_len = end - name;
292 if (*variable_name_size < (name_len + 1)) {
293 *variable_name_size = name_len + 1;
294 return EFI_BUFFER_TOO_SMALL;
296 end++; /* point to value */
300 utf8_utf16_strncpy(&p, name, name_len);
301 variable_name[name_len] = 0;
302 *variable_name_size = name_len + 1;
306 *(name - 1) = '\0'; /* guid need be null-terminated here */
307 uuid_str_to_bin(guid, (unsigned char *)vendor, UUID_STR_FORMAT_GUID);
311 parse_attr(end, attributes);
317 * efi_get_next_variable_name() - enumerate the current variable names
319 * @variable_name_size: size of variable_name buffer in byte
320 * @variable_name: name of uefi variable's name in u16
321 * @vendor: vendor's guid
323 * This function implements the GetNextVariableName service.
325 * See the Unified Extensible Firmware Interface (UEFI) specification for
328 * Return: status code
330 efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t *variable_name_size,
332 const efi_guid_t *vendor)
334 char *native_name, *variable;
335 ssize_t name_len, list_len;
337 char * const regexlist[] = {regex};
342 EFI_ENTRY("%p \"%ls\" %pUl", variable_name_size, variable_name, vendor);
344 if (!variable_name_size || !variable_name || !vendor)
345 return EFI_EXIT(EFI_INVALID_PARAMETER);
347 if (variable_name[0]) {
348 /* check null-terminated string */
349 for (i = 0; i < *variable_name_size; i++)
350 if (!variable_name[i])
352 if (i >= *variable_name_size)
353 return EFI_EXIT(EFI_INVALID_PARAMETER);
355 /* search for the last-returned variable */
356 ret = efi_to_native(&native_name, variable_name, vendor);
358 return EFI_EXIT(ret);
360 name_len = strlen(native_name);
361 for (variable = efi_variables_list; variable && *variable;) {
362 if (!strncmp(variable, native_name, name_len) &&
363 variable[name_len] == '=')
366 variable = strchr(variable, '\n');
372 if (!(variable && *variable))
373 return EFI_EXIT(EFI_INVALID_PARAMETER);
376 variable = strchr(variable, '\n');
379 if (!(variable && *variable))
380 return EFI_EXIT(EFI_NOT_FOUND);
383 *new search: free a list used in the previous search
385 free(efi_variables_list);
386 efi_variables_list = NULL;
387 efi_cur_variable = NULL;
389 snprintf(regex, 256, "efi_.*-.*-.*-.*-.*_.*");
390 list_len = hexport_r(&env_htab, '\n',
391 H_MATCH_REGEX | H_MATCH_KEY,
392 &efi_variables_list, 0, 1, regexlist);
393 /* 1 indicates that no match was found */
395 return EFI_EXIT(EFI_NOT_FOUND);
397 variable = efi_variables_list;
400 ret = parse_uboot_variable(variable, variable_name_size, variable_name,
401 vendor, &attributes);
403 return EFI_EXIT(ret);
407 * efi_set_variable() - set value of a UEFI variable
409 * This function implements the SetVariable runtime service.
411 * See the Unified Extensible Firmware Interface (UEFI) specification for
414 * @variable_name: name of the variable
415 * @vendor: vendor GUID
416 * @attributes: attributes of the variable
417 * @data_size: size of the buffer with the variable value
418 * @data: buffer with the variable value
419 * Return: status code
421 efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
422 const efi_guid_t *vendor, u32 attributes,
423 efi_uintn_t data_size, const void *data)
425 char *native_name = NULL, *val = NULL, *s;
426 efi_status_t ret = EFI_SUCCESS;
429 EFI_ENTRY("\"%ls\" %pUl %x %zu %p", variable_name, vendor, attributes,
432 /* TODO: implement APPEND_WRITE */
433 if (!variable_name || !*variable_name || !vendor ||
434 ((attributes & EFI_VARIABLE_RUNTIME_ACCESS) &&
435 !(attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)) ||
436 (attributes & EFI_VARIABLE_APPEND_WRITE)) {
437 ret = EFI_INVALID_PARAMETER;
441 ret = efi_to_native(&native_name, variable_name, vendor);
445 #define ACCESS_ATTR (EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS)
447 if ((data_size == 0) || !(attributes & ACCESS_ATTR)) {
448 /* delete the variable: */
449 env_set(native_name, NULL);
454 val = env_get(native_name);
456 parse_attr(val, &attr);
458 /* We should not free val */
460 if (attr & READ_ONLY) {
461 ret = EFI_WRITE_PROTECTED;
466 * attributes won't be changed
467 * TODO: take care of APPEND_WRITE once supported
469 if (attr != attributes) {
470 ret = EFI_INVALID_PARAMETER;
475 val = malloc(2 * data_size + strlen("{ro,run,boot,nv}(blob)") + 1);
477 ret = EFI_OUT_OF_RESOURCES;
485 * TODO: several attributes are not supported
487 attributes &= (EFI_VARIABLE_NON_VOLATILE |
488 EFI_VARIABLE_BOOTSERVICE_ACCESS |
489 EFI_VARIABLE_RUNTIME_ACCESS);
490 s += sprintf(s, "{");
492 u32 attr = 1 << (ffs(attributes) - 1);
494 if (attr == EFI_VARIABLE_NON_VOLATILE)
495 s += sprintf(s, "nv");
496 else if (attr == EFI_VARIABLE_BOOTSERVICE_ACCESS)
497 s += sprintf(s, "boot");
498 else if (attr == EFI_VARIABLE_RUNTIME_ACCESS)
499 s += sprintf(s, "run");
503 s += sprintf(s, ",");
505 s += sprintf(s, "}");
508 s += sprintf(s, "(blob)");
509 s = bin2hex(s, data, data_size);
512 EFI_PRINT("setting: %s=%s\n", native_name, val);
514 if (env_set(native_name, val))
515 ret = EFI_DEVICE_ERROR;
521 return EFI_EXIT(ret);
525 * efi_query_variable_info() - get information about EFI variables
527 * This function implements the QueryVariableInfo() runtime service.
529 * See the Unified Extensible Firmware Interface (UEFI) specification for
532 * @attributes: bitmask to select variables to be
534 * @maximum_variable_storage_size: maximum size of storage area for the
535 * selected variable types
536 * @remaining_variable_storage_size: remaining size of storage are for the
537 * selected variable types
538 * @maximum_variable_size: maximum size of a variable of the
540 * Returns: status code
542 efi_status_t __efi_runtime EFIAPI efi_query_variable_info(
544 u64 *maximum_variable_storage_size,
545 u64 *remaining_variable_storage_size,
546 u64 *maximum_variable_size)
548 return EFI_UNSUPPORTED;
552 * efi_get_variable_runtime() - runtime implementation of GetVariable()
554 * @variable_name: name of the variable
555 * @vendor: vendor GUID
556 * @attributes: attributes of the variable
557 * @data_size: size of the buffer to which the variable value is copied
558 * @data: buffer to which the variable value is copied
559 * Return: status code
561 static efi_status_t __efi_runtime EFIAPI
562 efi_get_variable_runtime(u16 *variable_name, const efi_guid_t *vendor,
563 u32 *attributes, efi_uintn_t *data_size, void *data)
565 return EFI_UNSUPPORTED;
569 * efi_get_next_variable_name_runtime() - runtime implementation of
572 * @variable_name_size: size of variable_name buffer in byte
573 * @variable_name: name of uefi variable's name in u16
574 * @vendor: vendor's guid
575 * Return: status code
577 static efi_status_t __efi_runtime EFIAPI
578 efi_get_next_variable_name_runtime(efi_uintn_t *variable_name_size,
579 u16 *variable_name, const efi_guid_t *vendor)
581 return EFI_UNSUPPORTED;
585 * efi_set_variable_runtime() - runtime implementation of SetVariable()
587 * @variable_name: name of the variable
588 * @vendor: vendor GUID
589 * @attributes: attributes of the variable
590 * @data_size: size of the buffer with the variable value
591 * @data: buffer with the variable value
592 * Return: status code
594 static efi_status_t __efi_runtime EFIAPI
595 efi_set_variable_runtime(u16 *variable_name, const efi_guid_t *vendor,
596 u32 attributes, efi_uintn_t data_size,
599 return EFI_UNSUPPORTED;
603 * efi_variables_boot_exit_notify() - notify ExitBootServices() is called
605 void efi_variables_boot_exit_notify(void)
607 efi_runtime_services.get_variable = efi_get_variable_runtime;
608 efi_runtime_services.get_next_variable_name =
609 efi_get_next_variable_name_runtime;
610 efi_runtime_services.set_variable = efi_set_variable_runtime;
611 efi_update_table_header_crc32(&efi_runtime_services.hdr);
615 * efi_init_variables() - initialize variable services
617 * Return: status code
619 efi_status_t efi_init_variables(void)