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