efivars.c revision 69e608411473ac56358ef35277563982d0565381
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/slab.h> 71#include <linux/ucs2_string.h> 72 73#define EFIVARS_VERSION "0.08" 74#define EFIVARS_DATE "2004-May-17" 75 76MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>"); 77MODULE_DESCRIPTION("sysfs interface to EFI Variables"); 78MODULE_LICENSE("GPL"); 79MODULE_VERSION(EFIVARS_VERSION); 80 81LIST_HEAD(efivar_sysfs_list); 82EXPORT_SYMBOL_GPL(efivar_sysfs_list); 83 84static struct kset *efivars_kset; 85 86static struct bin_attribute *efivars_new_var; 87static struct bin_attribute *efivars_del_var; 88 89struct efivar_attribute { 90 struct attribute attr; 91 ssize_t (*show) (struct efivar_entry *entry, char *buf); 92 ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count); 93}; 94 95#define EFIVAR_ATTR(_name, _mode, _show, _store) \ 96struct efivar_attribute efivar_attr_##_name = { \ 97 .attr = {.name = __stringify(_name), .mode = _mode}, \ 98 .show = _show, \ 99 .store = _store, \ 100}; 101 102#define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr) 103#define to_efivar_entry(obj) container_of(obj, struct efivar_entry, kobj) 104 105/* 106 * Prototype for sysfs creation function 107 */ 108static int 109efivar_create_sysfs_entry(struct efivar_entry *new_var); 110 111static ssize_t 112efivar_guid_read(struct efivar_entry *entry, char *buf) 113{ 114 struct efi_variable *var = &entry->var; 115 char *str = buf; 116 117 if (!entry || !buf) 118 return 0; 119 120 efi_guid_unparse(&var->VendorGuid, str); 121 str += strlen(str); 122 str += sprintf(str, "\n"); 123 124 return str - buf; 125} 126 127static ssize_t 128efivar_attr_read(struct efivar_entry *entry, char *buf) 129{ 130 struct efi_variable *var = &entry->var; 131 char *str = buf; 132 133 if (!entry || !buf) 134 return -EINVAL; 135 136 var->DataSize = 1024; 137 if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data)) 138 return -EIO; 139 140 if (var->Attributes & EFI_VARIABLE_NON_VOLATILE) 141 str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n"); 142 if (var->Attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS) 143 str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n"); 144 if (var->Attributes & EFI_VARIABLE_RUNTIME_ACCESS) 145 str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n"); 146 if (var->Attributes & EFI_VARIABLE_HARDWARE_ERROR_RECORD) 147 str += sprintf(str, "EFI_VARIABLE_HARDWARE_ERROR_RECORD\n"); 148 if (var->Attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) 149 str += sprintf(str, 150 "EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS\n"); 151 if (var->Attributes & 152 EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) 153 str += sprintf(str, 154 "EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS\n"); 155 if (var->Attributes & EFI_VARIABLE_APPEND_WRITE) 156 str += sprintf(str, "EFI_VARIABLE_APPEND_WRITE\n"); 157 return str - buf; 158} 159 160static ssize_t 161efivar_size_read(struct efivar_entry *entry, char *buf) 162{ 163 struct efi_variable *var = &entry->var; 164 char *str = buf; 165 166 if (!entry || !buf) 167 return -EINVAL; 168 169 var->DataSize = 1024; 170 if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data)) 171 return -EIO; 172 173 str += sprintf(str, "0x%lx\n", var->DataSize); 174 return str - buf; 175} 176 177static ssize_t 178efivar_data_read(struct efivar_entry *entry, char *buf) 179{ 180 struct efi_variable *var = &entry->var; 181 182 if (!entry || !buf) 183 return -EINVAL; 184 185 var->DataSize = 1024; 186 if (efivar_entry_get(entry, &var->Attributes, &var->DataSize, var->Data)) 187 return -EIO; 188 189 memcpy(buf, var->Data, var->DataSize); 190 return var->DataSize; 191} 192/* 193 * We allow each variable to be edited via rewriting the 194 * entire efi variable structure. 195 */ 196static ssize_t 197efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count) 198{ 199 struct efi_variable *new_var, *var = &entry->var; 200 int err; 201 202 if (count != sizeof(struct efi_variable)) 203 return -EINVAL; 204 205 new_var = (struct efi_variable *)buf; 206 /* 207 * If only updating the variable data, then the name 208 * and guid should remain the same 209 */ 210 if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) || 211 efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) { 212 printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n"); 213 return -EINVAL; 214 } 215 216 if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){ 217 printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n"); 218 return -EINVAL; 219 } 220 221 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 || 222 efivar_validate(new_var, new_var->Data, new_var->DataSize) == false) { 223 printk(KERN_ERR "efivars: Malformed variable content\n"); 224 return -EINVAL; 225 } 226 227 memcpy(&entry->var, new_var, count); 228 229 err = efivar_entry_set(entry, new_var->Attributes, 230 new_var->DataSize, new_var->Data, NULL); 231 if (err) { 232 printk(KERN_WARNING "efivars: set_variable() failed: status=%d\n", err); 233 return -EIO; 234 } 235 236 return count; 237} 238 239static ssize_t 240efivar_show_raw(struct efivar_entry *entry, char *buf) 241{ 242 struct efi_variable *var = &entry->var; 243 244 if (!entry || !buf) 245 return 0; 246 247 var->DataSize = 1024; 248 if (efivar_entry_get(entry, &entry->var.Attributes, 249 &entry->var.DataSize, entry->var.Data)) 250 return -EIO; 251 252 memcpy(buf, var, sizeof(*var)); 253 254 return sizeof(*var); 255} 256 257/* 258 * Generic read/write functions that call the specific functions of 259 * the attributes... 260 */ 261static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr, 262 char *buf) 263{ 264 struct efivar_entry *var = to_efivar_entry(kobj); 265 struct efivar_attribute *efivar_attr = to_efivar_attr(attr); 266 ssize_t ret = -EIO; 267 268 if (!capable(CAP_SYS_ADMIN)) 269 return -EACCES; 270 271 if (efivar_attr->show) { 272 ret = efivar_attr->show(var, buf); 273 } 274 return ret; 275} 276 277static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr, 278 const char *buf, size_t count) 279{ 280 struct efivar_entry *var = to_efivar_entry(kobj); 281 struct efivar_attribute *efivar_attr = to_efivar_attr(attr); 282 ssize_t ret = -EIO; 283 284 if (!capable(CAP_SYS_ADMIN)) 285 return -EACCES; 286 287 if (efivar_attr->store) 288 ret = efivar_attr->store(var, buf, count); 289 290 return ret; 291} 292 293static const struct sysfs_ops efivar_attr_ops = { 294 .show = efivar_attr_show, 295 .store = efivar_attr_store, 296}; 297 298static void efivar_release(struct kobject *kobj) 299{ 300 struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj); 301 kfree(var); 302} 303 304static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL); 305static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL); 306static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL); 307static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL); 308static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw); 309 310static struct attribute *def_attrs[] = { 311 &efivar_attr_guid.attr, 312 &efivar_attr_size.attr, 313 &efivar_attr_attributes.attr, 314 &efivar_attr_data.attr, 315 &efivar_attr_raw_var.attr, 316 NULL, 317}; 318 319static struct kobj_type efivar_ktype = { 320 .release = efivar_release, 321 .sysfs_ops = &efivar_attr_ops, 322 .default_attrs = def_attrs, 323}; 324 325static ssize_t efivar_create(struct file *filp, struct kobject *kobj, 326 struct bin_attribute *bin_attr, 327 char *buf, loff_t pos, size_t count) 328{ 329 struct efi_variable *new_var = (struct efi_variable *)buf; 330 struct efivar_entry *new_entry; 331 int err; 332 333 if (!capable(CAP_SYS_ADMIN)) 334 return -EACCES; 335 336 if ((new_var->Attributes & ~EFI_VARIABLE_MASK) != 0 || 337 efivar_validate(new_var, new_var->Data, new_var->DataSize) == false) { 338 printk(KERN_ERR "efivars: Malformed variable content\n"); 339 return -EINVAL; 340 } 341 342 new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL); 343 if (!new_entry) 344 return -ENOMEM; 345 346 memcpy(&new_entry->var, new_var, sizeof(*new_var)); 347 348 err = efivar_entry_set(new_entry, new_var->Attributes, new_var->DataSize, 349 new_var->Data, &efivar_sysfs_list); 350 if (err) { 351 if (err == -EEXIST) 352 err = -EINVAL; 353 goto out; 354 } 355 356 if (efivar_create_sysfs_entry(new_entry)) { 357 printk(KERN_WARNING "efivars: failed to create sysfs entry.\n"); 358 kfree(new_entry); 359 } 360 return count; 361 362out: 363 kfree(new_entry); 364 return err; 365} 366 367static ssize_t efivar_delete(struct file *filp, struct kobject *kobj, 368 struct bin_attribute *bin_attr, 369 char *buf, loff_t pos, size_t count) 370{ 371 struct efi_variable *del_var = (struct efi_variable *)buf; 372 struct efivar_entry *entry; 373 int err = 0; 374 375 if (!capable(CAP_SYS_ADMIN)) 376 return -EACCES; 377 378 efivar_entry_iter_begin(); 379 entry = efivar_entry_find(del_var->VariableName, del_var->VendorGuid, 380 &efivar_sysfs_list, true); 381 if (!entry) 382 err = -EINVAL; 383 else if (__efivar_entry_delete(entry)) 384 err = -EIO; 385 386 if (err) { 387 efivar_entry_iter_end(); 388 return err; 389 } 390 391 if (!entry->scanning) { 392 efivar_entry_iter_end(); 393 efivar_unregister(entry); 394 } else 395 efivar_entry_iter_end(); 396 397 /* It's dead Jim.... */ 398 return count; 399} 400 401/** 402 * efivar_create_sysfs_entry - create a new entry in sysfs 403 * @new_var: efivar entry to create 404 * 405 * Returns 1 on failure, 0 on success 406 */ 407static int 408efivar_create_sysfs_entry(struct efivar_entry *new_var) 409{ 410 int i, short_name_size; 411 char *short_name; 412 unsigned long variable_name_size; 413 efi_char16_t *variable_name; 414 415 variable_name = new_var->var.VariableName; 416 variable_name_size = ucs2_strlen(variable_name) * sizeof(efi_char16_t); 417 418 /* 419 * Length of the variable bytes in ASCII, plus the '-' separator, 420 * plus the GUID, plus trailing NUL 421 */ 422 short_name_size = variable_name_size / sizeof(efi_char16_t) 423 + 1 + EFI_VARIABLE_GUID_LEN + 1; 424 425 short_name = kzalloc(short_name_size, GFP_KERNEL); 426 427 if (!short_name) 428 return 1; 429 430 /* Convert Unicode to normal chars (assume top bits are 0), 431 ala UTF-8 */ 432 for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) { 433 short_name[i] = variable_name[i] & 0xFF; 434 } 435 /* This is ugly, but necessary to separate one vendor's 436 private variables from another's. */ 437 438 *(short_name + strlen(short_name)) = '-'; 439 efi_guid_unparse(&new_var->var.VendorGuid, 440 short_name + strlen(short_name)); 441 442 new_var->kobj.kset = efivars_kset; 443 444 i = kobject_init_and_add(&new_var->kobj, &efivar_ktype, 445 NULL, "%s", short_name); 446 kfree(short_name); 447 if (i) 448 return 1; 449 450 kobject_uevent(&new_var->kobj, KOBJ_ADD); 451 efivar_entry_add(new_var, &efivar_sysfs_list); 452 453 return 0; 454} 455 456static int 457create_efivars_bin_attributes(void) 458{ 459 struct bin_attribute *attr; 460 int error; 461 462 /* new_var */ 463 attr = kzalloc(sizeof(*attr), GFP_KERNEL); 464 if (!attr) 465 return -ENOMEM; 466 467 attr->attr.name = "new_var"; 468 attr->attr.mode = 0200; 469 attr->write = efivar_create; 470 efivars_new_var = attr; 471 472 /* del_var */ 473 attr = kzalloc(sizeof(*attr), GFP_KERNEL); 474 if (!attr) { 475 error = -ENOMEM; 476 goto out_free; 477 } 478 attr->attr.name = "del_var"; 479 attr->attr.mode = 0200; 480 attr->write = efivar_delete; 481 efivars_del_var = attr; 482 483 sysfs_bin_attr_init(efivars_new_var); 484 sysfs_bin_attr_init(efivars_del_var); 485 486 /* Register */ 487 error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_new_var); 488 if (error) { 489 printk(KERN_ERR "efivars: unable to create new_var sysfs file" 490 " due to error %d\n", error); 491 goto out_free; 492 } 493 494 error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_del_var); 495 if (error) { 496 printk(KERN_ERR "efivars: unable to create del_var sysfs file" 497 " due to error %d\n", error); 498 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var); 499 goto out_free; 500 } 501 502 return 0; 503out_free: 504 kfree(efivars_del_var); 505 efivars_del_var = NULL; 506 kfree(efivars_new_var); 507 efivars_new_var = NULL; 508 return error; 509} 510 511static int efivar_update_sysfs_entry(efi_char16_t *name, efi_guid_t vendor, 512 unsigned long name_size, void *data) 513{ 514 struct efivar_entry *entry = data; 515 516 if (efivar_entry_find(name, vendor, &efivar_sysfs_list, false)) 517 return 0; 518 519 memcpy(entry->var.VariableName, name, name_size); 520 memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t)); 521 522 return 1; 523} 524 525static void efivar_update_sysfs_entries(struct work_struct *work) 526{ 527 struct efivar_entry *entry; 528 int err; 529 530 /* Add new sysfs entries */ 531 while (1) { 532 entry = kzalloc(sizeof(*entry), GFP_KERNEL); 533 if (!entry) 534 return; 535 536 err = efivar_init(efivar_update_sysfs_entry, entry, 537 true, false, &efivar_sysfs_list); 538 if (!err) 539 break; 540 541 efivar_create_sysfs_entry(entry); 542 } 543 544 kfree(entry); 545} 546 547static int efivars_sysfs_callback(efi_char16_t *name, efi_guid_t vendor, 548 unsigned long name_size, void *data) 549{ 550 struct efivar_entry *entry; 551 552 entry = kzalloc(sizeof(*entry), GFP_KERNEL); 553 if (!entry) 554 return -ENOMEM; 555 556 memcpy(entry->var.VariableName, name, name_size); 557 memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t)); 558 559 efivar_create_sysfs_entry(entry); 560 561 return 0; 562} 563 564static int efivar_sysfs_destroy(struct efivar_entry *entry, void *data) 565{ 566 efivar_entry_remove(entry); 567 efivar_unregister(entry); 568 return 0; 569} 570 571static void efivars_sysfs_exit(void) 572{ 573 /* Remove all entries and destroy */ 574 __efivar_entry_iter(efivar_sysfs_destroy, &efivar_sysfs_list, NULL, NULL); 575 576 if (efivars_new_var) 577 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var); 578 if (efivars_del_var) 579 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_del_var); 580 kfree(efivars_new_var); 581 kfree(efivars_del_var); 582 kset_unregister(efivars_kset); 583} 584 585int efivars_sysfs_init(void) 586{ 587 struct kobject *parent_kobj = efivars_kobject(); 588 int error = 0; 589 590 if (!efi_enabled(EFI_RUNTIME_SERVICES)) 591 return -ENODEV; 592 593 /* No efivars has been registered yet */ 594 if (!parent_kobj) 595 return 0; 596 597 printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION, 598 EFIVARS_DATE); 599 600 efivars_kset = kset_create_and_add("vars", NULL, parent_kobj); 601 if (!efivars_kset) { 602 printk(KERN_ERR "efivars: Subsystem registration failed.\n"); 603 return -ENOMEM; 604 } 605 606 efivar_init(efivars_sysfs_callback, NULL, false, 607 true, &efivar_sysfs_list); 608 609 error = create_efivars_bin_attributes(); 610 if (error) { 611 efivars_sysfs_exit(); 612 return error; 613 } 614 615 INIT_WORK(&efivar_work, efivar_update_sysfs_entries); 616 617 return 0; 618} 619EXPORT_SYMBOL_GPL(efivars_sysfs_init); 620 621module_init(efivars_sysfs_init); 622module_exit(efivars_sysfs_exit); 623