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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/* 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);
244
245int param_set_charp(const char *val, const struct kernel_param *kp)
246{
247 if (strlen(val) > 1024) {
248 pr_err("%s: string parameter too long\n", kp->name);
249 return -ENOSPC;
250 }
251
252 maybe_kfree_parameter(*(char **)kp->arg);
253
254 /* This is a hack. We can't kmalloc in early boot, and we
255 * don't need to; this mangled commandline is preserved. */
256 if (slab_is_available()) {
257 *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
258 if (!*(char **)kp->arg)
259 return -ENOMEM;
260 strcpy(*(char **)kp->arg, val);
261 } else
262 *(const char **)kp->arg = val;
263
264 return 0;
265}
266EXPORT_SYMBOL(param_set_charp);
267
268int param_get_charp(char *buffer, const struct kernel_param *kp)
269{
270 return scnprintf(buffer, PAGE_SIZE, "%s\n", *((char **)kp->arg));
271}
272EXPORT_SYMBOL(param_get_charp);
273
274void param_free_charp(void *arg)
275{
276 maybe_kfree_parameter(*((char **)arg));
277}
278EXPORT_SYMBOL(param_free_charp);
279
280const struct kernel_param_ops param_ops_charp = {
281 .set = param_set_charp,
282 .get = param_get_charp,
283 .free = param_free_charp,
284};
285EXPORT_SYMBOL(param_ops_charp);
286
287/* Actually could be a bool or an int, for historical reasons. */
288int param_set_bool(const char *val, const struct kernel_param *kp)
289{
290 /* No equals means "set"... */
291 if (!val) val = "1";
292
293 /* One of =[yYnN01] */
294 return strtobool(val, kp->arg);
295}
296EXPORT_SYMBOL(param_set_bool);
297
298int param_get_bool(char *buffer, const struct kernel_param *kp)
299{
300 /* Y and N chosen as being relatively non-coder friendly */
301 return sprintf(buffer, "%c\n", *(bool *)kp->arg ? 'Y' : 'N');
302}
303EXPORT_SYMBOL(param_get_bool);
304
305const struct kernel_param_ops param_ops_bool = {
306 .flags = KERNEL_PARAM_OPS_FL_NOARG,
307 .set = param_set_bool,
308 .get = param_get_bool,
309};
310EXPORT_SYMBOL(param_ops_bool);
311
312int param_set_bool_enable_only(const char *val, const struct kernel_param *kp)
313{
314 int err = 0;
315 bool new_value;
316 bool orig_value = *(bool *)kp->arg;
317 struct kernel_param dummy_kp = *kp;
318
319 dummy_kp.arg = &new_value;
320
321 err = param_set_bool(val, &dummy_kp);
322 if (err)
323 return err;
324
325 /* Don't let them unset it once it's set! */
326 if (!new_value && orig_value)
327 return -EROFS;
328
329 if (new_value)
330 err = param_set_bool(val, kp);
331
332 return err;
333}
334EXPORT_SYMBOL_GPL(param_set_bool_enable_only);
335
336const struct kernel_param_ops param_ops_bool_enable_only = {
337 .flags = KERNEL_PARAM_OPS_FL_NOARG,
338 .set = param_set_bool_enable_only,
339 .get = param_get_bool,
340};
341EXPORT_SYMBOL_GPL(param_ops_bool_enable_only);
342
343/* This one must be bool. */
344int param_set_invbool(const char *val, const struct kernel_param *kp)
345{
346 int ret;
347 bool boolval;
348 struct kernel_param dummy;
349
350 dummy.arg = &boolval;
351 ret = param_set_bool(val, &dummy);
352 if (ret == 0)
353 *(bool *)kp->arg = !boolval;
354 return ret;
355}
356EXPORT_SYMBOL(param_set_invbool);
357
358int param_get_invbool(char *buffer, const struct kernel_param *kp)
359{
360 return sprintf(buffer, "%c\n", (*(bool *)kp->arg) ? 'N' : 'Y');
361}
362EXPORT_SYMBOL(param_get_invbool);
363
364const struct kernel_param_ops param_ops_invbool = {
365 .set = param_set_invbool,
366 .get = param_get_invbool,
367};
368EXPORT_SYMBOL(param_ops_invbool);
369
370int param_set_bint(const char *val, const struct kernel_param *kp)
371{
372 /* Match bool exactly, by re-using it. */
373 struct kernel_param boolkp = *kp;
374 bool v;
375 int ret;
376
377 boolkp.arg = &v;
378
379 ret = param_set_bool(val, &boolkp);
380 if (ret == 0)
381 *(int *)kp->arg = v;
382 return ret;
383}
384EXPORT_SYMBOL(param_set_bint);
385
386const struct kernel_param_ops param_ops_bint = {
387 .flags = KERNEL_PARAM_OPS_FL_NOARG,
388 .set = param_set_bint,
389 .get = param_get_int,
390};
391EXPORT_SYMBOL(param_ops_bint);
392
393/* We break the rule and mangle the string. */
394static int param_array(struct module *mod,
395 const char *name,
396 const char *val,
397 unsigned int min, unsigned int max,
398 void *elem, int elemsize,
399 int (*set)(const char *, const struct kernel_param *kp),
400 s16 level,
401 unsigned int *num)
402{
403 int ret;
404 struct kernel_param kp;
405 char save;
406
407 /* Get the name right for errors. */
408 kp.name = name;
409 kp.arg = elem;
410 kp.level = level;
411
412 *num = 0;
413 /* We expect a comma-separated list of values. */
414 do {
415 int len;
416
417 if (*num == max) {
418 pr_err("%s: can only take %i arguments\n", name, max);
419 return -EINVAL;
420 }
421 len = strcspn(val, ",");
422
423 /* nul-terminate and parse */
424 save = val[len];
425 ((char *)val)[len] = '\0';
426 check_kparam_locked(mod);
427 ret = set(val, &kp);
428
429 if (ret != 0)
430 return ret;
431 kp.arg += elemsize;
432 val += len+1;
433 (*num)++;
434 } while (save == ',');
435
436 if (*num < min) {
437 pr_err("%s: needs at least %i arguments\n", name, min);
438 return -EINVAL;
439 }
440 return 0;
441}
442
443static int param_array_set(const char *val, const struct kernel_param *kp)
444{
445 const struct kparam_array *arr = kp->arr;
446 unsigned int temp_num;
447
448 return param_array(kp->mod, kp->name, val, 1, arr->max, arr->elem,
449 arr->elemsize, arr->ops->set, kp->level,
450 arr->num ?: &temp_num);
451}
452
453static int param_array_get(char *buffer, const struct kernel_param *kp)
454{
455 int i, off, ret;
456 const struct kparam_array *arr = kp->arr;
457 struct kernel_param p = *kp;
458
459 for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
460 /* Replace \n with comma */
461 if (i)
462 buffer[off - 1] = ',';
463 p.arg = arr->elem + arr->elemsize * i;
464 check_kparam_locked(p.mod);
465 ret = arr->ops->get(buffer + off, &p);
466 if (ret < 0)
467 return ret;
468 off += ret;
469 }
470 buffer[off] = '\0';
471 return off;
472}
473
474static void param_array_free(void *arg)
475{
476 unsigned int i;
477 const struct kparam_array *arr = arg;
478
479 if (arr->ops->free)
480 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
481 arr->ops->free(arr->elem + arr->elemsize * i);
482}
483
484const struct kernel_param_ops param_array_ops = {
485 .set = param_array_set,
486 .get = param_array_get,
487 .free = param_array_free,
488};
489EXPORT_SYMBOL(param_array_ops);
490
491int param_set_copystring(const char *val, const struct kernel_param *kp)
492{
493 const struct kparam_string *kps = kp->str;
494
495 if (strlen(val)+1 > kps->maxlen) {
496 pr_err("%s: string doesn't fit in %u chars.\n",
497 kp->name, kps->maxlen-1);
498 return -ENOSPC;
499 }
500 strcpy(kps->string, val);
501 return 0;
502}
503EXPORT_SYMBOL(param_set_copystring);
504
505int param_get_string(char *buffer, const struct kernel_param *kp)
506{
507 const struct kparam_string *kps = kp->str;
508 return scnprintf(buffer, PAGE_SIZE, "%s\n", kps->string);
509}
510EXPORT_SYMBOL(param_get_string);
511
512const struct kernel_param_ops param_ops_string = {
513 .set = param_set_copystring,
514 .get = param_get_string,
515};
516EXPORT_SYMBOL(param_ops_string);
517
518/* sysfs output in /sys/modules/XYZ/parameters/ */
519#define to_module_attr(n) container_of(n, struct module_attribute, attr)
520#define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
521
522struct param_attribute
523{
524 struct module_attribute mattr;
525 const struct kernel_param *param;
526};
527
528struct module_param_attrs
529{
530 unsigned int num;
531 struct attribute_group grp;
532 struct param_attribute attrs[0];
533};
534
535#ifdef CONFIG_SYSFS
536#define to_param_attr(n) container_of(n, struct param_attribute, mattr)
537
538static ssize_t param_attr_show(struct module_attribute *mattr,
539 struct module_kobject *mk, char *buf)
540{
541 int count;
542 struct param_attribute *attribute = to_param_attr(mattr);
543
544 if (!attribute->param->ops->get)
545 return -EPERM;
546
547 kernel_param_lock(mk->mod);
548 count = attribute->param->ops->get(buf, attribute->param);
549 kernel_param_unlock(mk->mod);
550 return count;
551}
552
553/* sysfs always hands a nul-terminated string in buf. We rely on that. */
554static ssize_t param_attr_store(struct module_attribute *mattr,
555 struct module_kobject *mk,
556 const char *buf, size_t len)
557{
558 int err;
559 struct param_attribute *attribute = to_param_attr(mattr);
560
561 if (!attribute->param->ops->set)
562 return -EPERM;
563
564 kernel_param_lock(mk->mod);
565 if (param_check_unsafe(attribute->param))
566 err = attribute->param->ops->set(buf, attribute->param);
567 else
568 err = -EPERM;
569 kernel_param_unlock(mk->mod);
570 if (!err)
571 return len;
572 return err;
573}
574#endif
575
576#ifdef CONFIG_MODULES
577#define __modinit
578#else
579#define __modinit __init
580#endif
581
582#ifdef CONFIG_SYSFS
583void kernel_param_lock(struct module *mod)
584{
585 mutex_lock(KPARAM_MUTEX(mod));
586}
587
588void kernel_param_unlock(struct module *mod)
589{
590 mutex_unlock(KPARAM_MUTEX(mod));
591}
592
593EXPORT_SYMBOL(kernel_param_lock);
594EXPORT_SYMBOL(kernel_param_unlock);
595
596/*
597 * add_sysfs_param - add a parameter to sysfs
598 * @mk: struct module_kobject
599 * @kp: the actual parameter definition to add to sysfs
600 * @name: name of parameter
601 *
602 * Create a kobject if for a (per-module) parameter if mp NULL, and
603 * create file in sysfs. Returns an error on out of memory. Always cleans up
604 * if there's an error.
605 */
606static __modinit int add_sysfs_param(struct module_kobject *mk,
607 const struct kernel_param *kp,
608 const char *name)
609{
610 struct module_param_attrs *new_mp;
611 struct attribute **new_attrs;
612 unsigned int i;
613
614 /* We don't bother calling this with invisible parameters. */
615 BUG_ON(!kp->perm);
616
617 if (!mk->mp) {
618 /* First allocation. */
619 mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL);
620 if (!mk->mp)
621 return -ENOMEM;
622 mk->mp->grp.name = "parameters";
623 /* NULL-terminated attribute array. */
624 mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]),
625 GFP_KERNEL);
626 /* Caller will cleanup via free_module_param_attrs */
627 if (!mk->mp->grp.attrs)
628 return -ENOMEM;
629 }
630
631 /* Enlarge allocations. */
632 new_mp = krealloc(mk->mp,
633 sizeof(*mk->mp) +
634 sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1),
635 GFP_KERNEL);
636 if (!new_mp)
637 return -ENOMEM;
638 mk->mp = new_mp;
639
640 /* Extra pointer for NULL terminator */
641 new_attrs = krealloc(mk->mp->grp.attrs,
642 sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2),
643 GFP_KERNEL);
644 if (!new_attrs)
645 return -ENOMEM;
646 mk->mp->grp.attrs = new_attrs;
647
648 /* Tack new one on the end. */
649 memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0]));
650 sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr);
651 mk->mp->attrs[mk->mp->num].param = kp;
652 mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show;
653 /* Do not allow runtime DAC changes to make param writable. */
654 if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0)
655 mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store;
656 else
657 mk->mp->attrs[mk->mp->num].mattr.store = NULL;
658 mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name;
659 mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm;
660 mk->mp->num++;
661
662 /* Fix up all the pointers, since krealloc can move us */
663 for (i = 0; i < mk->mp->num; i++)
664 mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr;
665 mk->mp->grp.attrs[mk->mp->num] = NULL;
666 return 0;
667}
668
669#ifdef CONFIG_MODULES
670static void free_module_param_attrs(struct module_kobject *mk)
671{
672 if (mk->mp)
673 kfree(mk->mp->grp.attrs);
674 kfree(mk->mp);
675 mk->mp = NULL;
676}
677
678/*
679 * module_param_sysfs_setup - setup sysfs support for one module
680 * @mod: module
681 * @kparam: module parameters (array)
682 * @num_params: number of module parameters
683 *
684 * Adds sysfs entries for module parameters under
685 * /sys/module/[mod->name]/parameters/
686 */
687int module_param_sysfs_setup(struct module *mod,
688 const struct kernel_param *kparam,
689 unsigned int num_params)
690{
691 int i, err;
692 bool params = false;
693
694 for (i = 0; i < num_params; i++) {
695 if (kparam[i].perm == 0)
696 continue;
697 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
698 if (err) {
699 free_module_param_attrs(&mod->mkobj);
700 return err;
701 }
702 params = true;
703 }
704
705 if (!params)
706 return 0;
707
708 /* Create the param group. */
709 err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
710 if (err)
711 free_module_param_attrs(&mod->mkobj);
712 return err;
713}
714
715/*
716 * module_param_sysfs_remove - remove sysfs support for one module
717 * @mod: module
718 *
719 * Remove sysfs entries for module parameters and the corresponding
720 * kobject.
721 */
722void module_param_sysfs_remove(struct module *mod)
723{
724 if (mod->mkobj.mp) {
725 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
726 /* We are positive that no one is using any param
727 * attrs at this point. Deallocate immediately. */
728 free_module_param_attrs(&mod->mkobj);
729 }
730}
731#endif
732
733void destroy_params(const struct kernel_param *params, unsigned num)
734{
735 unsigned int i;
736
737 for (i = 0; i < num; i++)
738 if (params[i].ops->free)
739 params[i].ops->free(params[i].arg);
740}
741
742static struct module_kobject * __init locate_module_kobject(const char *name)
743{
744 struct module_kobject *mk;
745 struct kobject *kobj;
746 int err;
747
748 kobj = kset_find_obj(module_kset, name);
749 if (kobj) {
750 mk = to_module_kobject(kobj);
751 } else {
752 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
753 BUG_ON(!mk);
754
755 mk->mod = THIS_MODULE;
756 mk->kobj.kset = module_kset;
757 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
758 "%s", name);
759#ifdef CONFIG_MODULES
760 if (!err)
761 err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
762#endif
763 if (err) {
764 kobject_put(&mk->kobj);
765 pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
766 name, err);
767 return NULL;
768 }
769
770 /* So that we hold reference in both cases. */
771 kobject_get(&mk->kobj);
772 }
773
774 return mk;
775}
776
777static void __init kernel_add_sysfs_param(const char *name,
778 const struct kernel_param *kparam,
779 unsigned int name_skip)
780{
781 struct module_kobject *mk;
782 int err;
783
784 mk = locate_module_kobject(name);
785 if (!mk)
786 return;
787
788 /* We need to remove old parameters before adding more. */
789 if (mk->mp)
790 sysfs_remove_group(&mk->kobj, &mk->mp->grp);
791
792 /* These should not fail at boot. */
793 err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
794 BUG_ON(err);
795 err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
796 BUG_ON(err);
797 kobject_uevent(&mk->kobj, KOBJ_ADD);
798 kobject_put(&mk->kobj);
799}
800
801/*
802 * param_sysfs_builtin - add sysfs parameters for built-in modules
803 *
804 * Add module_parameters to sysfs for "modules" built into the kernel.
805 *
806 * The "module" name (KBUILD_MODNAME) is stored before a dot, the
807 * "parameter" name is stored behind a dot in kernel_param->name. So,
808 * extract the "module" name for all built-in kernel_param-eters,
809 * and for all who have the same, call kernel_add_sysfs_param.
810 */
811static void __init param_sysfs_builtin(void)
812{
813 const struct kernel_param *kp;
814 unsigned int name_len;
815 char modname[MODULE_NAME_LEN];
816
817 for (kp = __start___param; kp < __stop___param; kp++) {
818 char *dot;
819
820 if (kp->perm == 0)
821 continue;
822
823 dot = strchr(kp->name, '.');
824 if (!dot) {
825 /* This happens for core_param() */
826 strcpy(modname, "kernel");
827 name_len = 0;
828 } else {
829 name_len = dot - kp->name + 1;
830 strlcpy(modname, kp->name, name_len);
831 }
832 kernel_add_sysfs_param(modname, kp, name_len);
833 }
834}
835
836ssize_t __modver_version_show(struct module_attribute *mattr,
837 struct module_kobject *mk, char *buf)
838{
839 struct module_version_attribute *vattr =
840 container_of(mattr, struct module_version_attribute, mattr);
841
842 return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
843}
844
845extern const struct module_version_attribute *__start___modver[];
846extern const struct module_version_attribute *__stop___modver[];
847
848static void __init version_sysfs_builtin(void)
849{
850 const struct module_version_attribute **p;
851 struct module_kobject *mk;
852 int err;
853
854 for (p = __start___modver; p < __stop___modver; p++) {
855 const struct module_version_attribute *vattr = *p;
856
857 mk = locate_module_kobject(vattr->module_name);
858 if (mk) {
859 err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
860 WARN_ON_ONCE(err);
861 kobject_uevent(&mk->kobj, KOBJ_ADD);
862 kobject_put(&mk->kobj);
863 }
864 }
865}
866
867/* module-related sysfs stuff */
868
869static ssize_t module_attr_show(struct kobject *kobj,
870 struct attribute *attr,
871 char *buf)
872{
873 struct module_attribute *attribute;
874 struct module_kobject *mk;
875 int ret;
876
877 attribute = to_module_attr(attr);
878 mk = to_module_kobject(kobj);
879
880 if (!attribute->show)
881 return -EIO;
882
883 ret = attribute->show(attribute, mk, buf);
884
885 return ret;
886}
887
888static ssize_t module_attr_store(struct kobject *kobj,
889 struct attribute *attr,
890 const char *buf, size_t len)
891{
892 struct module_attribute *attribute;
893 struct module_kobject *mk;
894 int ret;
895
896 attribute = to_module_attr(attr);
897 mk = to_module_kobject(kobj);
898
899 if (!attribute->store)
900 return -EIO;
901
902 ret = attribute->store(attribute, mk, buf, len);
903
904 return ret;
905}
906
907static const struct sysfs_ops module_sysfs_ops = {
908 .show = module_attr_show,
909 .store = module_attr_store,
910};
911
912static int uevent_filter(struct kset *kset, struct kobject *kobj)
913{
914 struct kobj_type *ktype = get_ktype(kobj);
915
916 if (ktype == &module_ktype)
917 return 1;
918 return 0;
919}
920
921static const struct kset_uevent_ops module_uevent_ops = {
922 .filter = uevent_filter,
923};
924
925struct kset *module_kset;
926int module_sysfs_initialized;
927
928static void module_kobj_release(struct kobject *kobj)
929{
930 struct module_kobject *mk = to_module_kobject(kobj);
931 complete(mk->kobj_completion);
932}
933
934struct kobj_type module_ktype = {
935 .release = module_kobj_release,
936 .sysfs_ops = &module_sysfs_ops,
937};
938
939/*
940 * param_sysfs_init - wrapper for built-in params support
941 */
942static int __init param_sysfs_init(void)
943{
944 module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
945 if (!module_kset) {
946 printk(KERN_WARNING "%s (%d): error creating kset\n",
947 __FILE__, __LINE__);
948 return -ENOMEM;
949 }
950 module_sysfs_initialized = 1;
951
952 version_sysfs_builtin();
953 param_sysfs_builtin();
954
955 return 0;
956}
957subsys_initcall(param_sysfs_init);
958
959#endif /* CONFIG_SYSFS */