efivars.c revision 7b2dd6d2c4db3912771bfcfd7ac7264011a3c831
1/* 2 * Originally from efivars.c, 3 * 4 * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com> 5 * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com> 6 * 7 * This code takes all variables accessible from EFI runtime and 8 * exports them via sysfs 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License as published by 12 * the Free Software Foundation; either version 2 of the License, or 13 * (at your option) any later version. 14 * 15 * This program is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 * GNU General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with this program; if not, write to the Free Software 22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 23 * 24 * Changelog: 25 * 26 * 17 May 2004 - Matt Domsch <Matt_Domsch@dell.com> 27 * remove check for efi_enabled in exit 28 * add MODULE_VERSION 29 * 30 * 26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com> 31 * minor bug fixes 32 * 33 * 21 Apr 2004 - Matt Tolentino <matthew.e.tolentino@intel.com) 34 * converted driver to export variable information via sysfs 35 * and moved to drivers/firmware directory 36 * bumped revision number to v0.07 to reflect conversion & move 37 * 38 * 10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com> 39 * fix locking per Peter Chubb's findings 40 * 41 * 25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com> 42 * move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_unparse() 43 * 44 * 12 Feb 2002 - Matt Domsch <Matt_Domsch@dell.com> 45 * use list_for_each_safe when deleting vars. 46 * remove ifdef CONFIG_SMP around include <linux/smp.h> 47 * v0.04 release to linux-ia64@linuxia64.org 48 * 49 * 20 April 2001 - Matt Domsch <Matt_Domsch@dell.com> 50 * Moved vars from /proc/efi to /proc/efi/vars, and made 51 * efi.c own the /proc/efi directory. 52 * v0.03 release to linux-ia64@linuxia64.org 53 * 54 * 26 March 2001 - Matt Domsch <Matt_Domsch@dell.com> 55 * At the request of Stephane, moved ownership of /proc/efi 56 * to efi.c, and now efivars lives under /proc/efi/vars. 57 * 58 * 12 March 2001 - Matt Domsch <Matt_Domsch@dell.com> 59 * Feedback received from Stephane Eranian incorporated. 60 * efivar_write() checks copy_from_user() return value. 61 * efivar_read/write() returns proper errno. 62 * v0.02 release to linux-ia64@linuxia64.org 63 * 64 * 26 February 2001 - Matt Domsch <Matt_Domsch@dell.com> 65 * v0.01 release to linux-ia64@linuxia64.org 66 */ 67 68#include <linux/efi.h> 69#include <linux/module.h> 70#include <linux/ucs2_string.h> 71 72#define EFIVARS_VERSION "0.08" 73#define EFIVARS_DATE "2004-May-17" 74 75MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>"); 76MODULE_DESCRIPTION("sysfs interface to EFI Variables"); 77MODULE_LICENSE("GPL"); 78MODULE_VERSION(EFIVARS_VERSION); 79 80LIST_HEAD(efivar_sysfs_list); 81EXPORT_SYMBOL_GPL(efivar_sysfs_list); 82 83static struct kset *efivars_kset; 84 85static struct bin_attribute *efivars_new_var; 86static struct bin_attribute *efivars_del_var; 87 88struct efivar_attribute { 89 struct attribute attr; 90 ssize_t (*show) (struct efivar_entry *entry, char *buf); 91 ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count); 92}; 93 94#define EFIVAR_ATTR(_name, _mode, _show, _store) \ 95struct efivar_attribute efivar_attr_##_name = { \ 96 .attr = {.name = __stringify(_name), .mode = _mode}, \ 97 .show = _show, \ 98 .store = _store, \ 99}; 100 101#define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr) 102#define to_efivar_entry(obj) container_of(obj, struct efivar_entry, kobj) 103 104/* 105 * Prototype for sysfs creation function 106 */ 107static int 108efivar_create_sysfs_entry(struct efivar_entry *new_var); 109 110static ssize_t 111efivar_guid_read(struct efivar_entry *entry, char *buf) 112{ 113 struct efi_variable *var = &entry->var; 114 char *str = buf; 115 116 if (!entry || !buf) 117 return 0; 118 119 efi_guid_unparse(&var->VendorGuid, str); 120 str += strlen(str); 121 str += sprintf(str, "\n"); 122 123 return str - buf; 124} 125 126static ssize_t 127efivar_attr_read(struct efivar_entry *entry, char *buf) 128{ 129 struct efi_variable *var = &entry->var; 130 char *str = buf; 131 132 if (!entry || !buf) 133 return -EINVAL; 134 135 var->DataSize = 1024; 136 if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data)) 137 return -EIO; 138 139 if (var->Attributes & EFI_VARIABLE_NON_VOLATILE) 140 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n"); 141 if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS) 142 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n"); 143 if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS) 144 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n"); 145 if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD) 146 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n"); 147 if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) 148 str += sprintf(str, 149 "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n"); 150 if (var->Attributes & 151 EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) 152 str += sprintf(str, 153 "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n"); 154 if (var->Attributes & EFI_VARIABLE_APPEND_WRITE) 155 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n"); 156 return str - buf; 157} 158 159static ssize_t 160efivar_size_read(struct efivar_entry *entry, char *buf) 161{ 162 struct efi_variable *var = &entry->var; 163 char *str = buf; 164 165 if (!entry || !buf) 166 return -EINVAL; 167 168 var->DataSize = 1024; 169 if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data)) 170 return -EIO; 171 172 str += sprintf(str, "0x%lx\n", var->DataSize); 173 return str - buf; 174} 175 176static ssize_t 177efivar_data_read(struct efivar_entry *entry, char *buf) 178{ 179 struct efi_variable *var = &entry->var; 180 181 if (!entry || !buf) 182 return -EINVAL; 183 184 var->DataSize = 1024; 185 if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data)) 186 return -EIO; 187 188 memcpy(buf, var->Data, var->DataSize); 189 return var->DataSize; 190} 191/* 192 * We allow each variable to be edited via rewriting the 193 * entire efi variable structure. 194 */ 195static ssize_t 196efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count) 197{ 198 struct efi_variable *new_var, *var = &entry->var; 199 int err; 200 201 if (count != sizeof(struct efi_variable)) 202 return -EINVAL; 203 204 new_var = (struct efi_variable *)buf; 205 /* 206 * If only updating the variable data, then the name 207 * and guid should remain the same 208 */ 209 if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) || 210 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) { 211 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n"); 212 return -EINVAL; 213 } 214 215 if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){ 216 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n"); 217 return -EINVAL; 218 } 219 220 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 || 221 efivar_validate(new_var, new_var->Data, new_var->DataSize) == false) { 222 printk(KERN_ERR "efivars: Malformed variable content\n"); 223 return -EINVAL; 224 } 225 226 memcpy(&entry->var, new_var, count); 227 228 err = efivar_entry_set(entry, new_var->Attributes, 229 new_var->DataSize, new_var->Data, false); 230 if (err) { 231 printk(KERN_WARNING "efivars: set_variable() failed: status=%d\n", err); 232 return -EIO; 233 } 234 235 return count; 236} 237 238static ssize_t 239efivar_show_raw(struct efivar_entry *entry, char *buf) 240{ 241 struct efi_variable *var = &entry->var; 242 243 if (!entry || !buf) 244 return 0; 245 246 var->DataSize = 1024; 247 if (efivar_entry_get(entry, &entry->var.Attributes, 248 &entry->var.DataSize, entry->var.Data)) 249 return -EIO; 250 251 memcpy(buf, var, sizeof(*var)); 252 253 return sizeof(*var); 254} 255 256/* 257 * Generic read/write functions that call the specific functions of 258 * the attributes... 259 */ 260static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr, 261 char *buf) 262{ 263 struct efivar_entry *var = to_efivar_entry(kobj); 264 struct efivar_attribute *efivar_attr = to_efivar_attr(attr); 265 ssize_t ret = -EIO; 266 267 if (!capable(CAP_SYS_ADMIN)) 268 return -EACCES; 269 270 if (efivar_attr->show) { 271 ret = efivar_attr->show(var, buf); 272 } 273 return ret; 274} 275 276static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr, 277 const char *buf, size_t count) 278{ 279 struct efivar_entry *var = to_efivar_entry(kobj); 280 struct efivar_attribute *efivar_attr = to_efivar_attr(attr); 281 ssize_t ret = -EIO; 282 283 if (!capable(CAP_SYS_ADMIN)) 284 return -EACCES; 285 286 if (efivar_attr->store) 287 ret = efivar_attr->store(var, buf, count); 288 289 return ret; 290} 291 292static const struct sysfs_ops efivar_attr_ops = { 293 .show = efivar_attr_show, 294 .store = efivar_attr_store, 295}; 296 297static void efivar_release(struct kobject *kobj) 298{ 299 struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj); 300 kfree(var); 301} 302 303static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL); 304static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL); 305static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL); 306static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL); 307static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw); 308 309static struct attribute *def_attrs[] = { 310 &efivar_attr_guid.attr, 311 &efivar_attr_size.attr, 312 &efivar_attr_attributes.attr, 313 &efivar_attr_data.attr, 314 &efivar_attr_raw_var.attr, 315 NULL, 316}; 317 318static struct kobj_type efivar_ktype = { 319 .release = efivar_release, 320 .sysfs_ops = &efivar_attr_ops, 321 .default_attrs = def_attrs, 322}; 323 324static ssize_t efivar_create(struct file *filp, struct kobject *kobj, 325 struct bin_attribute *bin_attr, 326 char *buf, loff_t pos, size_t count) 327{ 328 struct efi_variable *new_var = (struct efi_variable *)buf; 329 struct efivar_entry *new_entry; 330 int err; 331 332 if (!capable(CAP_SYS_ADMIN)) 333 return -EACCES; 334 335 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 || 336 efivar_validate(new_var, new_var->Data, new_var->DataSize) == false) { 337 printk(KERN_ERR "efivars: Malformed variable content\n"); 338 return -EINVAL; 339 } 340 341 new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL); 342 if (!new_entry) 343 return -ENOMEM; 344 345 memcpy(&new_entry->var, new_var, sizeof(*new_var)); 346 347 err = efivar_entry_set(new_entry, new_var->Attributes, new_var->DataSize, 348 new_var->Data, &efivar_sysfs_list); 349 if (err) { 350 if (err == -EEXIST) 351 err = -EINVAL; 352 goto out; 353 } 354 355 if (efivar_create_sysfs_entry(new_entry)) { 356 printk(KERN_WARNING "efivars: failed to create sysfs entry.\n"); 357 kfree(new_entry); 358 } 359 return count; 360 361out: 362 kfree(new_entry); 363 return err; 364} 365 366static ssize_t efivar_delete(struct file *filp, struct kobject *kobj, 367 struct bin_attribute *bin_attr, 368 char *buf, loff_t pos, size_t count) 369{ 370 struct efi_variable *del_var = (struct efi_variable *)buf; 371 struct efivar_entry *entry; 372 int err = 0; 373 374 if (!capable(CAP_SYS_ADMIN)) 375 return -EACCES; 376 377 efivar_entry_iter_begin(); 378 entry = efivar_entry_find(del_var->VariableName, del_var->VendorGuid, 379 &efivar_sysfs_list, true); 380 if (!entry) 381 err = -EINVAL; 382 else if (__efivar_entry_delete(entry)) 383 err = -EIO; 384 385 efivar_entry_iter_end(); 386 387 if (err) 388 return err; 389 390 efivar_unregister(entry); 391 392 /* It's dead Jim.... */ 393 return count; 394} 395 396/** 397 * efivar_create_sysfs_entry - create a new entry in sysfs 398 * @new_var: efivar entry to create 399 * 400 * Returns 1 on failure, 0 on success 401 */ 402static int 403efivar_create_sysfs_entry(struct efivar_entry *new_var) 404{ 405 int i, short_name_size; 406 char *short_name; 407 unsigned long variable_name_size; 408 efi_char16_t *variable_name; 409 410 variable_name = new_var->var.VariableName; 411 variable_name_size = ucs2_strlen(variable_name) * sizeof(efi_char16_t); 412 413 /* 414 * Length of the variable bytes in ASCII, plus the '-' separator, 415 * plus the GUID, plus trailing NUL 416 */ 417 short_name_size = variable_name_size / sizeof(efi_char16_t) 418 + 1 + EFI_VARIABLE_GUID_LEN + 1; 419 420 short_name = kzalloc(short_name_size, GFP_KERNEL); 421 422 if (!short_name) 423 return 1; 424 425 /* Convert Unicode to normal chars (assume top bits are 0), 426 ala UTF-8 */ 427 for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) { 428 short_name[i] = variable_name[i] & 0xFF; 429 } 430 /* This is ugly, but necessary to separate one vendor's 431 private variables from another's. */ 432 433 *(short_name + strlen(short_name)) = '-'; 434 efi_guid_unparse(&new_var->var.VendorGuid, 435 short_name + strlen(short_name)); 436 437 new_var->kobj.kset = efivars_kset; 438 439 i = kobject_init_and_add(&new_var->kobj, &efivar_ktype, 440 NULL, "%s", short_name); 441 kfree(short_name); 442 if (i) 443 return 1; 444 445 kobject_uevent(&new_var->kobj, KOBJ_ADD); 446 efivar_entry_add(new_var, &efivar_sysfs_list); 447 448 return 0; 449} 450 451static int 452create_efivars_bin_attributes(void) 453{ 454 struct bin_attribute *attr; 455 int error; 456 457 /* new_var */ 458 attr = kzalloc(sizeof(*attr), GFP_KERNEL); 459 if (!attr) 460 return -ENOMEM; 461 462 attr->attr.name = "new_var"; 463 attr->attr.mode = 0200; 464 attr->write = efivar_create; 465 efivars_new_var = attr; 466 467 /* del_var */ 468 attr = kzalloc(sizeof(*attr), GFP_KERNEL); 469 if (!attr) { 470 error = -ENOMEM; 471 goto out_free; 472 } 473 attr->attr.name = "del_var"; 474 attr->attr.mode = 0200; 475 attr->write = efivar_delete; 476 efivars_del_var = attr; 477 478 sysfs_bin_attr_init(efivars_new_var); 479 sysfs_bin_attr_init(efivars_del_var); 480 481 /* Register */ 482 error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_new_var); 483 if (error) { 484 printk(KERN_ERR "efivars: unable to create new_var sysfs file" 485 " due to error %d\n", error); 486 goto out_free; 487 } 488 489 error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_del_var); 490 if (error) { 491 printk(KERN_ERR "efivars: unable to create del_var sysfs file" 492 " due to error %d\n", error); 493 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var); 494 goto out_free; 495 } 496 497 return 0; 498out_free: 499 kfree(efivars_del_var); 500 efivars_del_var = NULL; 501 kfree(efivars_new_var); 502 efivars_new_var = NULL; 503 return error; 504} 505 506static int efivar_update_sysfs_entry(efi_char16_t *name, efi_guid_t vendor, 507 unsigned long name_size, void *data) 508{ 509 struct efivar_entry *entry = data; 510 511 if (efivar_entry_find(name, vendor, &efivar_sysfs_list, false)) 512 return 0; 513 514 memcpy(entry->var.VariableName, name, name_size); 515 memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t)); 516 517 return 1; 518} 519 520static void efivar_update_sysfs_entries(struct work_struct *work) 521{ 522 struct efivar_entry *entry; 523 int err; 524 525 entry = kzalloc(sizeof(*entry), GFP_KERNEL); 526 if (!entry) 527 return; 528 529 /* Add new sysfs entries */ 530 while (1) { 531 memset(entry, 0, sizeof(*entry)); 532 533 err = efivar_init(efivar_update_sysfs_entry, entry, 534 true, false, &efivar_sysfs_list); 535 if (!err) 536 break; 537 538 efivar_create_sysfs_entry(entry); 539 } 540 541 kfree(entry); 542} 543 544static int efivars_sysfs_callback(efi_char16_t *name, efi_guid_t vendor, 545 unsigned long name_size, void *data) 546{ 547 struct efivar_entry *entry; 548 549 entry = kzalloc(sizeof(*entry), GFP_KERNEL); 550 if (!entry) 551 return -ENOMEM; 552 553 memcpy(entry->var.VariableName, name, name_size); 554 memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t)); 555 556 efivar_create_sysfs_entry(entry); 557 558 return 0; 559} 560 561static int efivar_sysfs_destroy(struct efivar_entry *entry, void *data) 562{ 563 efivar_entry_remove(entry); 564 efivar_unregister(entry); 565 return 0; 566} 567 568void efivars_sysfs_exit(void) 569{ 570 /* Remove all entries and destroy */ 571 __efivar_entry_iter(efivar_sysfs_destroy, &efivar_sysfs_list, NULL, NULL); 572 573 if (efivars_new_var) 574 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var); 575 if (efivars_del_var) 576 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_del_var); 577 kfree(efivars_new_var); 578 kfree(efivars_del_var); 579 kset_unregister(efivars_kset); 580} 581 582int efivars_sysfs_init(void) 583{ 584 struct kobject *parent_kobj = efivars_kobject(); 585 int error = 0; 586 587 /* No efivars has been registered yet */ 588 if (!parent_kobj) 589 return 0; 590 591 printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION, 592 EFIVARS_DATE); 593 594 efivars_kset = kset_create_and_add("vars", NULL, parent_kobj); 595 if (!efivars_kset) { 596 printk(KERN_ERR "efivars: Subsystem registration failed.\n"); 597 return -ENOMEM; 598 } 599 600 efivar_init(efivars_sysfs_callback, NULL, false, 601 true, &efivar_sysfs_list); 602 603 error = create_efivars_bin_attributes(); 604 if (error) { 605 efivars_sysfs_exit(); 606 return error; 607 } 608 609 INIT_WORK(&efivar_work, efivar_update_sysfs_entries); 610 611 return 0; 612} 613EXPORT_SYMBOL_GPL(efivars_sysfs_init); 614 615module_init(efivars_sysfs_init); 616module_exit(efivars_sysfs_exit); 617