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 : &param_lock)
26#else
27#define KPARAM_MUTEX(mod)	(&param_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(&params[i]))
143				err = params[i].ops->set(val, &params[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, &param, &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 */
997