1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Helpers for initial module or kernel cmdline parsing
4 * Copyright (C) 2001 Rusty Russell.
5 */
6 #include <linux/ctype.h>
7 #include <linux/device.h>
8 #include <linux/err.h>
9 #include <linux/errno.h>
10 #include <linux/kernel.h>
11 #include <linux/kstrtox.h>
12 #include <linux/module.h>
13 #include <linux/moduleparam.h>
14 #include <linux/overflow.h>
15 #include <linux/security.h>
16 #include <linux/slab.h>
17 #include <linux/string.h>
18
19 #ifdef CONFIG_SYSFS
20 /* Protects all built-in parameters, modules use their own param_lock */
21 static DEFINE_MUTEX(param_lock);
22
23 /* Use the module's mutex, or if built-in use the built-in mutex */
24 #ifdef CONFIG_MODULES
25 #define KPARAM_MUTEX(mod) ((mod) ? &(mod)->param_lock : ¶m_lock)
26 #else
27 #define KPARAM_MUTEX(mod) (¶m_lock)
28 #endif
29
30 static inline void check_kparam_locked(struct module *mod)
31 {
32 BUG_ON(!mutex_is_locked(KPARAM_MUTEX(mod)));
33 }
34 #else
35 static inline void check_kparam_locked(struct module *mod)
36 {
37 }
38 #endif /* !CONFIG_SYSFS */
39
40 /* This just allows us to keep track of which parameters are kmalloced. */
41 struct kmalloced_param {
42 struct list_head list;
43 char val[];
44 };
45 static LIST_HEAD(kmalloced_params);
46 static DEFINE_SPINLOCK(kmalloced_params_lock);
47
48 static void *kmalloc_parameter(unsigned int size)
49 {
50 struct kmalloced_param *p;
51
52 p = kmalloc(size_add(sizeof(*p), size), GFP_KERNEL);
53 if (!p)
54 return NULL;
55
56 spin_lock(&kmalloced_params_lock);
57 list_add(&p->list, &kmalloced_params);
58 spin_unlock(&kmalloced_params_lock);
59
60 return p->val;
61 }
62
63 /* Does nothing if parameter wasn't kmalloced above. */
64 static void maybe_kfree_parameter(void *param)
65 {
66 struct kmalloced_param *p;
67
68 spin_lock(&kmalloced_params_lock);
69 list_for_each_entry(p, &kmalloced_params, list) {
70 if (p->val == param) {
71 list_del(&p->list);
72 kfree(p);
73 break;
74 }
75 }
76 spin_unlock(&kmalloced_params_lock);
77 }
78
79 static char dash2underscore(char c)
80 {
81 if (c == '-')
82 return '_';
83 return c;
84 }
85
86 bool parameqn(const char *a, const char *b, size_t n)
87 {
88 size_t i;
89
90 for (i = 0; i < n; i++) {
91 if (dash2underscore(a[i]) != dash2underscore(b[i]))
92 return false;
93 }
94 return true;
95 }
96
97 bool parameq(const char *a, const char *b)
98 {
99 return parameqn(a, b, strlen(a)+1);
100 }
101
102 static bool param_check_unsafe(const struct kernel_param *kp)
103 {
104 if (kp->flags & KERNEL_PARAM_FL_HWPARAM &&
105 security_locked_down(LOCKDOWN_MODULE_PARAMETERS))
106 return false;
107
108 if (kp->flags & KERNEL_PARAM_FL_UNSAFE) {
109 pr_notice("Setting dangerous option %s - tainting kernel\n",
110 kp->name);
111 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
112 }
113
114 return true;
115 }
116
117 static int parse_one(char *param,
118 char *val,
119 const char *doing,
120 const struct kernel_param *params,
121 unsigned num_params,
122 s16 min_level,
123 s16 max_level,
124 void *arg, parse_unknown_fn handle_unknown)
125 {
126 unsigned int i;
127 int err;
128
129 /* Find parameter */
130 for (i = 0; i < num_params; i++) {
131 if (parameq(param, params[i].name)) {
132 if (params[i].level < min_level
133 || params[i].level > max_level)
134 return 0;
135 /* No one handled NULL, so do it here. */
136 if (!val &&
137 !(params[i].ops->flags & KERNEL_PARAM_OPS_FL_NOARG))
138 return -EINVAL;
139 pr_debug("handling %s with %p\n", param,
140 params[i].ops->set);
141 kernel_param_lock(params[i].mod);
142 if (param_check_unsafe(¶ms[i]))
143 err = params[i].ops->set(val, ¶ms[i]);
144 else
145 err = -EPERM;
146 kernel_param_unlock(params[i].mod);
147 return err;
148 }
149 }
150
151 if (handle_unknown) {
152 pr_debug("doing %s: %s='%s'\n", doing, param, val);
153 return handle_unknown(param, val, doing, arg);
154 }
155
156 pr_debug("Unknown argument '%s'\n", param);
157 return -ENOENT;
158 }
159
160 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
161 char *parse_args(const char *doing,
162 char *args,
163 const struct kernel_param *params,
164 unsigned num,
165 s16 min_level,
166 s16 max_level,
167 void *arg, parse_unknown_fn unknown)
168 {
169 char *param, *val, *err = NULL;
170
171 /* Chew leading spaces */
172 args = skip_spaces(args);
173
174 if (*args)
175 pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
176
177 while (*args) {
178 int ret;
179 int irq_was_disabled;
180
181 args = next_arg(args, ¶m, &val);
182 /* Stop at -- */
183 if (!val && strcmp(param, "--") == 0)
184 return err ?: args;
185 irq_was_disabled = irqs_disabled();
186 ret = parse_one(param, val, doing, params, num,
187 min_level, max_level, arg, unknown);
188 if (irq_was_disabled && !irqs_disabled())
189 pr_warn("%s: option '%s' enabled irq's!\n",
190 doing, param);
191
192 switch (ret) {
193 case 0:
194 continue;
195 case -ENOENT:
196 pr_err("%s: Unknown parameter `%s'\n", doing, param);
197 break;
198 case -ENOSPC:
199 pr_err("%s: `%s' too large for parameter `%s'\n",
200 doing, val ?: "", param);
201 break;
202 default:
203 pr_err("%s: `%s' invalid for parameter `%s'\n",
204 doing, val ?: "", param);
205 break;
206 }
207
208 err = ERR_PTR(ret);
209 }
210
211 return err;
212 }
213
214 /* Lazy bastard, eh? */
215 #define STANDARD_PARAM_DEF(name, type, format, strtolfn) \
216 int param_set_##name(const char *val, const struct kernel_param *kp) \
217 { \
218 return strtolfn(val, 0, (type *)kp->arg); \
219 } \
220 int param_get_##name(char *buffer, const struct kernel_param *kp) \
221 { \
222 return scnprintf(buffer, PAGE_SIZE, format "\n", \
223 *((type *)kp->arg)); \
224 } \
225 const struct kernel_param_ops param_ops_##name = { \
226 .set = param_set_##name, \
227 .get = param_get_##name, \
228 }; \
229 EXPORT_SYMBOL(param_set_##name); \
230 EXPORT_SYMBOL(param_get_##name); \
231 EXPORT_SYMBOL(param_ops_##name)
232
233
234 STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", kstrtou8);
235 STANDARD_PARAM_DEF(short, short, "%hi", kstrtos16);
236 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", kstrtou16);
237 STANDARD_PARAM_DEF(int, int, "%i", kstrtoint);
238 STANDARD_PARAM_DEF(uint, unsigned int, "%u", kstrtouint);
239 STANDARD_PARAM_DEF(long, long, "%li", kstrtol);
240 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", kstrtoul);
241 STANDARD_PARAM_DEF(ullong, unsigned long long, "%llu", kstrtoull);
242 STANDARD_PARAM_DEF(hexint, unsigned int, "%#08x", kstrtouint);
243
244 int param_set_uint_minmax(const char *val, const struct kernel_param *kp,
245 unsigned int min, unsigned int max)
246 {
247 unsigned int num;
248 int ret;
249
250 if (!val)
251 return -EINVAL;
252 ret = kstrtouint(val, 0, &num);
253 if (ret)
254 return ret;
255 if (num < min || num > max)
256 return -EINVAL;
257 *((unsigned int *)kp->arg) = num;
258 return 0;
259 }
260 EXPORT_SYMBOL_GPL(param_set_uint_minmax);
261
262 int param_set_charp(const char *val, const struct kernel_param *kp)
263 {
264 size_t len, maxlen = 1024;
265
266 len = strnlen(val, maxlen + 1);
267 if (len == maxlen + 1) {
268 pr_err("%s: string parameter too long\n", kp->name);
269 return -ENOSPC;
270 }
271
272 maybe_kfree_parameter(*(char **)kp->arg);
273
274 /*
275 * This is a hack. We can't kmalloc() in early boot, and we
276 * don't need to; this mangled commandline is preserved.
277 */
278 if (slab_is_available()) {
279 *(char **)kp->arg = kmalloc_parameter(len + 1);
280 if (!*(char **)kp->arg)
281 return -ENOMEM;
282 strcpy(*(char **)kp->arg, val);
283 } else
284 *(const char **)kp->arg = val;
285
286 return 0;
287 }
288 EXPORT_SYMBOL(param_set_charp);
289
290 int param_get_charp(char *buffer, const struct kernel_param *kp)
291 {
292 return scnprintf(buffer, PAGE_SIZE, "%s\n", *((char **)kp->arg));
293 }
294 EXPORT_SYMBOL(param_get_charp);
295
296 void param_free_charp(void *arg)
297 {
298 maybe_kfree_parameter(*((char **)arg));
299 }
300 EXPORT_SYMBOL(param_free_charp);
301
302 const struct kernel_param_ops param_ops_charp = {
303 .set = param_set_charp,
304 .get = param_get_charp,
305 .free = param_free_charp,
306 };
307 EXPORT_SYMBOL(param_ops_charp);
308
309 /* Actually could be a bool or an int, for historical reasons. */
310 int param_set_bool(const char *val, const struct kernel_param *kp)
311 {
312 /* No equals means "set"... */
313 if (!val) val = "1";
314
315 /* One of =[yYnN01] */
316 return kstrtobool(val, kp->arg);
317 }
318 EXPORT_SYMBOL(param_set_bool);
319
320 int param_get_bool(char *buffer, const struct kernel_param *kp)
321 {
322 /* Y and N chosen as being relatively non-coder friendly */
323 return sprintf(buffer, "%c\n", *(bool *)kp->arg ? 'Y' : 'N');
324 }
325 EXPORT_SYMBOL(param_get_bool);
326
327 const struct kernel_param_ops param_ops_bool = {
328 .flags = KERNEL_PARAM_OPS_FL_NOARG,
329 .set = param_set_bool,
330 .get = param_get_bool,
331 };
332 EXPORT_SYMBOL(param_ops_bool);
333
334 int param_set_bool_enable_only(const char *val, const struct kernel_param *kp)
335 {
336 int err;
337 bool new_value;
338 bool orig_value = *(bool *)kp->arg;
339 struct kernel_param dummy_kp = *kp;
340
341 dummy_kp.arg = &new_value;
342
343 err = param_set_bool(val, &dummy_kp);
344 if (err)
345 return err;
346
347 /* Don't let them unset it once it's set! */
348 if (!new_value && orig_value)
349 return -EROFS;
350
351 if (new_value)
352 err = param_set_bool(val, kp);
353
354 return err;
355 }
356 EXPORT_SYMBOL_GPL(param_set_bool_enable_only);
357
358 const struct kernel_param_ops param_ops_bool_enable_only = {
359 .flags = KERNEL_PARAM_OPS_FL_NOARG,
360 .set = param_set_bool_enable_only,
361 .get = param_get_bool,
362 };
363 EXPORT_SYMBOL_GPL(param_ops_bool_enable_only);
364
365 /* This one must be bool. */
366 int param_set_invbool(const char *val, const struct kernel_param *kp)
367 {
368 int ret;
369 bool boolval;
370 struct kernel_param dummy;
371
372 dummy.arg = &boolval;
373 ret = param_set_bool(val, &dummy);
374 if (ret == 0)
375 *(bool *)kp->arg = !boolval;
376 return ret;
377 }
378 EXPORT_SYMBOL(param_set_invbool);
379
380 int param_get_invbool(char *buffer, const struct kernel_param *kp)
381 {
382 return sprintf(buffer, "%c\n", (*(bool *)kp->arg) ? 'N' : 'Y');
383 }
384 EXPORT_SYMBOL(param_get_invbool);
385
386 const struct kernel_param_ops param_ops_invbool = {
387 .set = param_set_invbool,
388 .get = param_get_invbool,
389 };
390 EXPORT_SYMBOL(param_ops_invbool);
391
392 int param_set_bint(const char *val, const struct kernel_param *kp)
393 {
394 /* Match bool exactly, by re-using it. */
395 struct kernel_param boolkp = *kp;
396 bool v;
397 int ret;
398
399 boolkp.arg = &v;
400
401 ret = param_set_bool(val, &boolkp);
402 if (ret == 0)
403 *(int *)kp->arg = v;
404 return ret;
405 }
406 EXPORT_SYMBOL(param_set_bint);
407
408 const struct kernel_param_ops param_ops_bint = {
409 .flags = KERNEL_PARAM_OPS_FL_NOARG,
410 .set = param_set_bint,
411 .get = param_get_int,
412 };
413 EXPORT_SYMBOL(param_ops_bint);
414
415 /* We break the rule and mangle the string. */
416 static int param_array(struct module *mod,
417 const char *name,
418 const char *val,
419 unsigned int min, unsigned int max,
420 void *elem, int elemsize,
421 int (*set)(const char *, const struct kernel_param *kp),
422 s16 level,
423 unsigned int *num)
424 {
425 int ret;
426 struct kernel_param kp;
427 char save;
428
429 /* Get the name right for errors. */
430 kp.name = name;
431 kp.arg = elem;
432 kp.level = level;
433
434 *num = 0;
435 /* We expect a comma-separated list of values. */
436 do {
437 int len;
438
439 if (*num == max) {
440 pr_err("%s: can only take %i arguments\n", name, max);
441 return -EINVAL;
442 }
443 len = strcspn(val, ",");
444
445 /* nul-terminate and parse */
446 save = val[len];
447 ((char *)val)[len] = '\0';
448 check_kparam_locked(mod);
449 ret = set(val, &kp);
450
451 if (ret != 0)
452 return ret;
453 kp.arg += elemsize;
454 val += len+1;
455 (*num)++;
456 } while (save == ',');
457
458 if (*num < min) {
459 pr_err("%s: needs at least %i arguments\n", name, min);
460 return -EINVAL;
461 }
462 return 0;
463 }
464
465 static int param_array_set(const char *val, const struct kernel_param *kp)
466 {
467 const struct kparam_array *arr = kp->arr;
468 unsigned int temp_num;
469
470 return param_array(kp->mod, kp->name, val, 1, arr->max, arr->elem,
471 arr->elemsize, arr->ops->set, kp->level,
472 arr->num ?: &temp_num);
473 }
474
475 static int param_array_get(char *buffer, const struct kernel_param *kp)
476 {
477 int i, off, ret;
478 const struct kparam_array *arr = kp->arr;
479 struct kernel_param p = *kp;
480
481 for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
482 /* Replace \n with comma */
483 if (i)
484 buffer[off - 1] = ',';
485 p.arg = arr->elem + arr->elemsize * i;
486 check_kparam_locked(p.mod);
487 ret = arr->ops->get(buffer + off, &p);
488 if (ret < 0)
489 return ret;
490 off += ret;
491 }
492 buffer[off] = '\0';
493 return off;
494 }
495
496 static void param_array_free(void *arg)
497 {
498 unsigned int i;
499 const struct kparam_array *arr = arg;
500
501 if (arr->ops->free)
502 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
503 arr->ops->free(arr->elem + arr->elemsize * i);
504 }
505
506 const struct kernel_param_ops param_array_ops = {
507 .set = param_array_set,
508 .get = param_array_get,
509 .free = param_array_free,
510 };
511 EXPORT_SYMBOL(param_array_ops);
512
513 int param_set_copystring(const char *val, const struct kernel_param *kp)
514 {
515 const struct kparam_string *kps = kp->str;
516
517 if (strnlen(val, kps->maxlen) == kps->maxlen) {
518 pr_err("%s: string doesn't fit in %u chars.\n",
519 kp->name, kps->maxlen-1);
520 return -ENOSPC;
521 }
522 strcpy(kps->string, val);
523 return 0;
524 }
525 EXPORT_SYMBOL(param_set_copystring);
526
527 int param_get_string(char *buffer, const struct kernel_param *kp)
528 {
529 const struct kparam_string *kps = kp->str;
530 return scnprintf(buffer, PAGE_SIZE, "%s\n", kps->string);
531 }
532 EXPORT_SYMBOL(param_get_string);
533
534 const struct kernel_param_ops param_ops_string = {
535 .set = param_set_copystring,
536 .get = param_get_string,
537 };
538 EXPORT_SYMBOL(param_ops_string);
539
540 /* sysfs output in /sys/modules/XYZ/parameters/ */
541 #define to_module_attr(n) container_of(n, struct module_attribute, attr)
542 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
543
544 struct param_attribute
545 {
546 struct module_attribute mattr;
547 const struct kernel_param *param;
548 };
549
550 struct module_param_attrs
551 {
552 unsigned int num;
553 struct attribute_group grp;
554 struct param_attribute attrs[];
555 };
556
557 #ifdef CONFIG_SYSFS
558 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
559
560 static ssize_t param_attr_show(struct module_attribute *mattr,
561 struct module_kobject *mk, char *buf)
562 {
563 int count;
564 struct param_attribute *attribute = to_param_attr(mattr);
565
566 if (!attribute->param->ops->get)
567 return -EPERM;
568
569 kernel_param_lock(mk->mod);
570 count = attribute->param->ops->get(buf, attribute->param);
571 kernel_param_unlock(mk->mod);
572 return count;
573 }
574
575 /* sysfs always hands a nul-terminated string in buf. We rely on that. */
576 static ssize_t param_attr_store(struct module_attribute *mattr,
577 struct module_kobject *mk,
578 const char *buf, size_t len)
579 {
580 int err;
581 struct param_attribute *attribute = to_param_attr(mattr);
582
583 if (!attribute->param->ops->set)
584 return -EPERM;
585
586 kernel_param_lock(mk->mod);
587 if (param_check_unsafe(attribute->param))
588 err = attribute->param->ops->set(buf, attribute->param);
589 else
590 err = -EPERM;
591 kernel_param_unlock(mk->mod);
592 if (!err)
593 return len;
594 return err;
595 }
596 #endif
597
598 #ifdef CONFIG_MODULES
599 #define __modinit
600 #else
601 #define __modinit __init
602 #endif
603
604 #ifdef CONFIG_SYSFS
605 void kernel_param_lock(struct module *mod)
606 {
607 mutex_lock(KPARAM_MUTEX(mod));
608 }
609
610 void kernel_param_unlock(struct module *mod)
611 {
612 mutex_unlock(KPARAM_MUTEX(mod));
613 }
614
615 EXPORT_SYMBOL(kernel_param_lock);
616 EXPORT_SYMBOL(kernel_param_unlock);
617
618 /*
619 * add_sysfs_param - add a parameter to sysfs
620 * @mk: struct module_kobject
621 * @kp: the actual parameter definition to add to sysfs
622 * @name: name of parameter
623 *
624 * Create a kobject if for a (per-module) parameter if mp NULL, and
625 * create file in sysfs. Returns an error on out of memory. Always cleans up
626 * if there's an error.
627 */
628 static __modinit int add_sysfs_param(struct module_kobject *mk,
629 const struct kernel_param *kp,
630 const char *name)
631 {
632 struct module_param_attrs *new_mp;
633 struct attribute **new_attrs;
634 unsigned int i;
635
636 /* We don't bother calling this with invisible parameters. */
637 BUG_ON(!kp->perm);
638
639 if (!mk->mp) {
640 /* First allocation. */
641 mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL);
642 if (!mk->mp)
643 return -ENOMEM;
644 mk->mp->grp.name = "parameters";
645 /* NULL-terminated attribute array. */
646 mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]),
647 GFP_KERNEL);
648 /* Caller will cleanup via free_module_param_attrs */
649 if (!mk->mp->grp.attrs)
650 return -ENOMEM;
651 }
652
653 /* Enlarge allocations. */
654 new_mp = krealloc(mk->mp,
655 sizeof(*mk->mp) +
656 sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1),
657 GFP_KERNEL);
658 if (!new_mp)
659 return -ENOMEM;
660 mk->mp = new_mp;
661
662 /* Extra pointer for NULL terminator */
663 new_attrs = krealloc(mk->mp->grp.attrs,
664 sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2),
665 GFP_KERNEL);
666 if (!new_attrs)
667 return -ENOMEM;
668 mk->mp->grp.attrs = new_attrs;
669
670 /* Tack new one on the end. */
671 memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0]));
672 sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr);
673 mk->mp->attrs[mk->mp->num].param = kp;
674 mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show;
675 /* Do not allow runtime DAC changes to make param writable. */
676 if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0)
677 mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store;
678 else
679 mk->mp->attrs[mk->mp->num].mattr.store = NULL;
680 mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name;
681 mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm;
682 mk->mp->num++;
683
684 /* Fix up all the pointers, since krealloc can move us */
685 for (i = 0; i < mk->mp->num; i++)
686 mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr;
687 mk->mp->grp.attrs[mk->mp->num] = NULL;
688 return 0;
689 }
690
691 #ifdef CONFIG_MODULES
692 static void free_module_param_attrs(struct module_kobject *mk)
693 {
694 if (mk->mp)
695 kfree(mk->mp->grp.attrs);
696 kfree(mk->mp);
697 mk->mp = NULL;
698 }
699
700 /*
701 * module_param_sysfs_setup - setup sysfs support for one module
702 * @mod: module
703 * @kparam: module parameters (array)
704 * @num_params: number of module parameters
705 *
706 * Adds sysfs entries for module parameters under
707 * /sys/module/[mod->name]/parameters/
708 */
709 int module_param_sysfs_setup(struct module *mod,
710 const struct kernel_param *kparam,
711 unsigned int num_params)
712 {
713 int i, err;
714 bool params = false;
715
716 for (i = 0; i < num_params; i++) {
717 if (kparam[i].perm == 0)
718 continue;
719 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
720 if (err) {
721 free_module_param_attrs(&mod->mkobj);
722 return err;
723 }
724 params = true;
725 }
726
727 if (!params)
728 return 0;
729
730 /* Create the param group. */
731 err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
732 if (err)
733 free_module_param_attrs(&mod->mkobj);
734 return err;
735 }
736
737 /*
738 * module_param_sysfs_remove - remove sysfs support for one module
739 * @mod: module
740 *
741 * Remove sysfs entries for module parameters and the corresponding
742 * kobject.
743 */
744 void module_param_sysfs_remove(struct module *mod)
745 {
746 if (mod->mkobj.mp) {
747 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
748 /*
749 * We are positive that no one is using any param
750 * attrs at this point. Deallocate immediately.
751 */
752 free_module_param_attrs(&mod->mkobj);
753 }
754 }
755 #endif
756
757 void destroy_params(const struct kernel_param *params, unsigned num)
758 {
759 unsigned int i;
760
761 for (i = 0; i < num; i++)
762 if (params[i].ops->free)
763 params[i].ops->free(params[i].arg);
764 }
765
766 static struct module_kobject * __init locate_module_kobject(const char *name)
767 {
768 struct module_kobject *mk;
769 struct kobject *kobj;
770 int err;
771
772 kobj = kset_find_obj(module_kset, name);
773 if (kobj) {
774 mk = to_module_kobject(kobj);
775 } else {
776 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
777 BUG_ON(!mk);
778
779 mk->mod = THIS_MODULE;
780 mk->kobj.kset = module_kset;
781 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
782 "%s", name);
783 #ifdef CONFIG_MODULES
784 if (!err)
785 err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
786 #endif
787 if (err) {
788 kobject_put(&mk->kobj);
789 pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
790 name, err);
791 return NULL;
792 }
793
794 /* So that we hold reference in both cases. */
795 kobject_get(&mk->kobj);
796 }
797
798 return mk;
799 }
800
801 static void __init kernel_add_sysfs_param(const char *name,
802 const struct kernel_param *kparam,
803 unsigned int name_skip)
804 {
805 struct module_kobject *mk;
806 int err;
807
808 mk = locate_module_kobject(name);
809 if (!mk)
810 return;
811
812 /* We need to remove old parameters before adding more. */
813 if (mk->mp)
814 sysfs_remove_group(&mk->kobj, &mk->mp->grp);
815
816 /* These should not fail at boot. */
817 err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
818 BUG_ON(err);
819 err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
820 BUG_ON(err);
821 kobject_uevent(&mk->kobj, KOBJ_ADD);
822 kobject_put(&mk->kobj);
823 }
824
825 /*
826 * param_sysfs_builtin - add sysfs parameters for built-in modules
827 *
828 * Add module_parameters to sysfs for "modules" built into the kernel.
829 *
830 * The "module" name (KBUILD_MODNAME) is stored before a dot, the
831 * "parameter" name is stored behind a dot in kernel_param->name. So,
832 * extract the "module" name for all built-in kernel_param-eters,
833 * and for all who have the same, call kernel_add_sysfs_param.
834 */
835 static void __init param_sysfs_builtin(void)
836 {
837 const struct kernel_param *kp;
838 unsigned int name_len;
839 char modname[MODULE_NAME_LEN];
840
841 for (kp = __start___param; kp < __stop___param; kp++) {
842 char *dot;
843
844 if (kp->perm == 0)
845 continue;
846
847 dot = strchr(kp->name, '.');
848 if (!dot) {
849 /* This happens for core_param() */
850 strcpy(modname, "kernel");
851 name_len = 0;
852 } else {
853 name_len = dot - kp->name + 1;
854 strscpy(modname, kp->name, name_len);
855 }
856 kernel_add_sysfs_param(modname, kp, name_len);
857 }
858 }
859
860 ssize_t __modver_version_show(struct module_attribute *mattr,
861 struct module_kobject *mk, char *buf)
862 {
863 struct module_version_attribute *vattr =
864 container_of(mattr, struct module_version_attribute, mattr);
865
866 return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
867 }
868
869 extern const struct module_version_attribute __start___modver[];
870 extern const struct module_version_attribute __stop___modver[];
871
872 static void __init version_sysfs_builtin(void)
873 {
874 const struct module_version_attribute *vattr;
875 struct module_kobject *mk;
876 int err;
877
878 for (vattr = __start___modver; vattr < __stop___modver; vattr++) {
879 mk = locate_module_kobject(vattr->module_name);
880 if (mk) {
881 err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
882 WARN_ON_ONCE(err);
883 kobject_uevent(&mk->kobj, KOBJ_ADD);
884 kobject_put(&mk->kobj);
885 }
886 }
887 }
888
889 /* module-related sysfs stuff */
890
891 static ssize_t module_attr_show(struct kobject *kobj,
892 struct attribute *attr,
893 char *buf)
894 {
895 struct module_attribute *attribute;
896 struct module_kobject *mk;
897 int ret;
898
899 attribute = to_module_attr(attr);
900 mk = to_module_kobject(kobj);
901
902 if (!attribute->show)
903 return -EIO;
904
905 ret = attribute->show(attribute, mk, buf);
906
907 return ret;
908 }
909
910 static ssize_t module_attr_store(struct kobject *kobj,
911 struct attribute *attr,
912 const char *buf, size_t len)
913 {
914 struct module_attribute *attribute;
915 struct module_kobject *mk;
916 int ret;
917
918 attribute = to_module_attr(attr);
919 mk = to_module_kobject(kobj);
920
921 if (!attribute->store)
922 return -EIO;
923
924 ret = attribute->store(attribute, mk, buf, len);
925
926 return ret;
927 }
928
929 static const struct sysfs_ops module_sysfs_ops = {
930 .show = module_attr_show,
931 .store = module_attr_store,
932 };
933
934 static int uevent_filter(const struct kobject *kobj)
935 {
936 const struct kobj_type *ktype = get_ktype(kobj);
937
938 if (ktype == &module_ktype)
939 return 1;
940 return 0;
941 }
942
943 static const struct kset_uevent_ops module_uevent_ops = {
944 .filter = uevent_filter,
945 };
946
947 struct kset *module_kset;
948
949 static void module_kobj_release(struct kobject *kobj)
950 {
951 struct module_kobject *mk = to_module_kobject(kobj);
952 complete(mk->kobj_completion);
953 }
954
955 const struct kobj_type module_ktype = {
956 .release = module_kobj_release,
957 .sysfs_ops = &module_sysfs_ops,
958 };
959
960 /*
961 * param_sysfs_init - create "module" kset
962 *
963 * This must be done before the initramfs is unpacked and
964 * request_module() thus becomes possible, because otherwise the
965 * module load would fail in mod_sysfs_init.
966 */
967 static int __init param_sysfs_init(void)
968 {
969 module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
970 if (!module_kset) {
971 printk(KERN_WARNING "%s (%d): error creating kset\n",
972 __FILE__, __LINE__);
973 return -ENOMEM;
974 }
975
976 return 0;
977 }
978 subsys_initcall(param_sysfs_init);
979
980 /*
981 * param_sysfs_builtin_init - add sysfs version and parameter
982 * attributes for built-in modules
983 */
984 static int __init param_sysfs_builtin_init(void)
985 {
986 if (!module_kset)
987 return -ENOMEM;
988
989 version_sysfs_builtin();
990 param_sysfs_builtin();
991
992 return 0;
993 }
994 late_initcall(param_sysfs_builtin_init);
995
996 #endif /* CONFIG_SYSFS */
997
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.