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
76 MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
77 MODULE_DESCRIPTION("sysfs interface to EFI Variables");
78 MODULE_LICENSE("GPL");
79 MODULE_VERSION(EFIVARS_VERSION);
80
81 LIST_HEAD(efivar_sysfs_list);
82 EXPORT_SYMBOL_GPL(efivar_sysfs_list);
83
84 static struct kset *efivars_kset;
85
86 static struct bin_attribute *efivars_new_var;
87 static struct bin_attribute *efivars_del_var;
88
89 struct 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) \
96 struct 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 */
108 static int
109 efivar_create_sysfs_entry(struct efivar_entry *new_var);
110
111 static ssize_t
efivar_guid_read(struct efivar_entry * entry,char * buf)112 efivar_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
127 static ssize_t
efivar_attr_read(struct efivar_entry * entry,char * buf)128 efivar_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
160 static ssize_t
efivar_size_read(struct efivar_entry * entry,char * buf)161 efivar_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
177 static ssize_t
efivar_data_read(struct efivar_entry * entry,char * buf)178 efivar_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 */
196 static ssize_t
efivar_store_raw(struct efivar_entry * entry,const char * buf,size_t count)197 efivar_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, false);
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
239 static ssize_t
efivar_show_raw(struct efivar_entry * entry,char * buf)240 efivar_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 */
efivar_attr_show(struct kobject * kobj,struct attribute * attr,char * buf)261 static 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
efivar_attr_store(struct kobject * kobj,struct attribute * attr,const char * buf,size_t count)277 static 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
293 static const struct sysfs_ops efivar_attr_ops = {
294 .show = efivar_attr_show,
295 .store = efivar_attr_store,
296 };
297
efivar_release(struct kobject * kobj)298 static void efivar_release(struct kobject *kobj)
299 {
300 struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
301 kfree(var);
302 }
303
304 static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL);
305 static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL);
306 static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL);
307 static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL);
308 static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw);
309
310 static 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
319 static struct kobj_type efivar_ktype = {
320 .release = efivar_release,
321 .sysfs_ops = &efivar_attr_ops,
322 .default_attrs = def_attrs,
323 };
324
efivar_create(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t pos,size_t count)325 static 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
362 out:
363 kfree(new_entry);
364 return err;
365 }
366
efivar_delete(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t pos,size_t count)367 static 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 efivar_entry_iter_end();
387
388 if (err)
389 return err;
390
391 efivar_unregister(entry);
392
393 /* It's dead Jim.... */
394 return count;
395 }
396
397 /**
398 * efivar_create_sysfs_entry - create a new entry in sysfs
399 * @new_var: efivar entry to create
400 *
401 * Returns 1 on failure, 0 on success
402 */
403 static int
efivar_create_sysfs_entry(struct efivar_entry * new_var)404 efivar_create_sysfs_entry(struct efivar_entry *new_var)
405 {
406 int i, short_name_size;
407 char *short_name;
408 unsigned long variable_name_size;
409 efi_char16_t *variable_name;
410
411 variable_name = new_var->var.VariableName;
412 variable_name_size = ucs2_strlen(variable_name) * sizeof(efi_char16_t);
413
414 /*
415 * Length of the variable bytes in ASCII, plus the '-' separator,
416 * plus the GUID, plus trailing NUL
417 */
418 short_name_size = variable_name_size / sizeof(efi_char16_t)
419 + 1 + EFI_VARIABLE_GUID_LEN + 1;
420
421 short_name = kzalloc(short_name_size, GFP_KERNEL);
422
423 if (!short_name)
424 return 1;
425
426 /* Convert Unicode to normal chars (assume top bits are 0),
427 ala UTF-8 */
428 for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) {
429 short_name[i] = variable_name[i] & 0xFF;
430 }
431 /* This is ugly, but necessary to separate one vendor's
432 private variables from another's. */
433
434 *(short_name + strlen(short_name)) = '-';
435 efi_guid_unparse(&new_var->var.VendorGuid,
436 short_name + strlen(short_name));
437
438 new_var->kobj.kset = efivars_kset;
439
440 i = kobject_init_and_add(&new_var->kobj, &efivar_ktype,
441 NULL, "%s", short_name);
442 kfree(short_name);
443 if (i)
444 return 1;
445
446 kobject_uevent(&new_var->kobj, KOBJ_ADD);
447 efivar_entry_add(new_var, &efivar_sysfs_list);
448
449 return 0;
450 }
451
452 static int
create_efivars_bin_attributes(void)453 create_efivars_bin_attributes(void)
454 {
455 struct bin_attribute *attr;
456 int error;
457
458 /* new_var */
459 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
460 if (!attr)
461 return -ENOMEM;
462
463 attr->attr.name = "new_var";
464 attr->attr.mode = 0200;
465 attr->write = efivar_create;
466 efivars_new_var = attr;
467
468 /* del_var */
469 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
470 if (!attr) {
471 error = -ENOMEM;
472 goto out_free;
473 }
474 attr->attr.name = "del_var";
475 attr->attr.mode = 0200;
476 attr->write = efivar_delete;
477 efivars_del_var = attr;
478
479 sysfs_bin_attr_init(efivars_new_var);
480 sysfs_bin_attr_init(efivars_del_var);
481
482 /* Register */
483 error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_new_var);
484 if (error) {
485 printk(KERN_ERR "efivars: unable to create new_var sysfs file"
486 " due to error %d\n", error);
487 goto out_free;
488 }
489
490 error = sysfs_create_bin_file(&efivars_kset->kobj, efivars_del_var);
491 if (error) {
492 printk(KERN_ERR "efivars: unable to create del_var sysfs file"
493 " due to error %d\n", error);
494 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var);
495 goto out_free;
496 }
497
498 return 0;
499 out_free:
500 kfree(efivars_del_var);
501 efivars_del_var = NULL;
502 kfree(efivars_new_var);
503 efivars_new_var = NULL;
504 return error;
505 }
506
efivar_update_sysfs_entry(efi_char16_t * name,efi_guid_t vendor,unsigned long name_size,void * data)507 static int efivar_update_sysfs_entry(efi_char16_t *name, efi_guid_t vendor,
508 unsigned long name_size, void *data)
509 {
510 struct efivar_entry *entry = data;
511
512 if (efivar_entry_find(name, vendor, &efivar_sysfs_list, false))
513 return 0;
514
515 memcpy(entry->var.VariableName, name, name_size);
516 memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
517
518 return 1;
519 }
520
efivar_update_sysfs_entries(struct work_struct * work)521 static void efivar_update_sysfs_entries(struct work_struct *work)
522 {
523 struct efivar_entry *entry;
524 int err;
525
526 /* Add new sysfs entries */
527 while (1) {
528 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
529 if (!entry)
530 return;
531
532 err = efivar_init(efivar_update_sysfs_entry, entry,
533 true, false, &efivar_sysfs_list);
534 if (!err)
535 break;
536
537 efivar_create_sysfs_entry(entry);
538 }
539
540 kfree(entry);
541 }
542
efivars_sysfs_callback(efi_char16_t * name,efi_guid_t vendor,unsigned long name_size,void * data)543 static int efivars_sysfs_callback(efi_char16_t *name, efi_guid_t vendor,
544 unsigned long name_size, void *data)
545 {
546 struct efivar_entry *entry;
547
548 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
549 if (!entry)
550 return -ENOMEM;
551
552 memcpy(entry->var.VariableName, name, name_size);
553 memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
554
555 efivar_create_sysfs_entry(entry);
556
557 return 0;
558 }
559
efivar_sysfs_destroy(struct efivar_entry * entry,void * data)560 static int efivar_sysfs_destroy(struct efivar_entry *entry, void *data)
561 {
562 efivar_entry_remove(entry);
563 efivar_unregister(entry);
564 return 0;
565 }
566
efivars_sysfs_exit(void)567 void efivars_sysfs_exit(void)
568 {
569 /* Remove all entries and destroy */
570 __efivar_entry_iter(efivar_sysfs_destroy, &efivar_sysfs_list, NULL, NULL);
571
572 if (efivars_new_var)
573 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_new_var);
574 if (efivars_del_var)
575 sysfs_remove_bin_file(&efivars_kset->kobj, efivars_del_var);
576 kfree(efivars_new_var);
577 kfree(efivars_del_var);
578 kset_unregister(efivars_kset);
579 }
580
efivars_sysfs_init(void)581 int efivars_sysfs_init(void)
582 {
583 struct kobject *parent_kobj = efivars_kobject();
584 int error = 0;
585
586 /* No efivars has been registered yet */
587 if (!parent_kobj)
588 return 0;
589
590 printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION,
591 EFIVARS_DATE);
592
593 efivars_kset = kset_create_and_add("vars", NULL, parent_kobj);
594 if (!efivars_kset) {
595 printk(KERN_ERR "efivars: Subsystem registration failed.\n");
596 return -ENOMEM;
597 }
598
599 efivar_init(efivars_sysfs_callback, NULL, false,
600 true, &efivar_sysfs_list);
601
602 error = create_efivars_bin_attributes();
603 if (error) {
604 efivars_sysfs_exit();
605 return error;
606 }
607
608 INIT_WORK(&efivar_work, efivar_update_sysfs_entries);
609
610 return 0;
611 }
612 EXPORT_SYMBOL_GPL(efivars_sysfs_init);
613
614 module_init(efivars_sysfs_init);
615 module_exit(efivars_sysfs_exit);
616