1/* Helpers for initial module or kernel cmdline parsing
2   Copyright (C) 2001 Rusty Russell.
3
4    This program is free software; you can redistribute it and/or modify
5    it under the terms of the GNU General Public License as published by
6    the Free Software Foundation; either version 2 of the License, or
7    (at your option) any later version.
8
9    This program is distributed in the hope that it will be useful,
10    but WITHOUT ANY WARRANTY; without even the implied warranty of
11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12    GNU General Public License for more details.
13
14    You should have received a copy of the GNU General Public License
15    along with this program; if not, write to the Free Software
16    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
17*/
18#include <linux/kernel.h>
19#include <linux/string.h>
20#include <linux/errno.h>
21#include <linux/module.h>
22#include <linux/moduleparam.h>
23#include <linux/device.h>
24#include <linux/err.h>
25#include <linux/slab.h>
26#include <linux/ctype.h>
27
28/* Protects all parameters, and incidentally kmalloced_param list. */
29static DEFINE_MUTEX(param_lock);
30
31/* This just allows us to keep track of which parameters are kmalloced. */
32struct kmalloced_param {
33	struct list_head list;
34	char val[];
35};
36static LIST_HEAD(kmalloced_params);
37
38static void *kmalloc_parameter(unsigned int size)
39{
40	struct kmalloced_param *p;
41
42	p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
43	if (!p)
44		return NULL;
45
46	list_add(&p->list, &kmalloced_params);
47	return p->val;
48}
49
50/* Does nothing if parameter wasn't kmalloced above. */
51static void maybe_kfree_parameter(void *param)
52{
53	struct kmalloced_param *p;
54
55	list_for_each_entry(p, &kmalloced_params, list) {
56		if (p->val == param) {
57			list_del(&p->list);
58			kfree(p);
59			break;
60		}
61	}
62}
63
64static char dash2underscore(char c)
65{
66	if (c == '-')
67		return '_';
68	return c;
69}
70
71bool parameqn(const char *a, const char *b, size_t n)
72{
73	size_t i;
74
75	for (i = 0; i < n; i++) {
76		if (dash2underscore(a[i]) != dash2underscore(b[i]))
77			return false;
78	}
79	return true;
80}
81
82bool parameq(const char *a, const char *b)
83{
84	return parameqn(a, b, strlen(a)+1);
85}
86
87static void param_check_unsafe(const struct kernel_param *kp)
88{
89	if (kp->flags & KERNEL_PARAM_FL_UNSAFE) {
90		pr_warn("Setting dangerous option %s - tainting kernel\n",
91			kp->name);
92		add_taint(TAINT_USER, LOCKDEP_STILL_OK);
93	}
94}
95
96static int parse_one(char *param,
97		     char *val,
98		     const char *doing,
99		     const struct kernel_param *params,
100		     unsigned num_params,
101		     s16 min_level,
102		     s16 max_level,
103		     int (*handle_unknown)(char *param, char *val,
104				     const char *doing))
105{
106	unsigned int i;
107	int err;
108
109	/* Find parameter */
110	for (i = 0; i < num_params; i++) {
111		if (parameq(param, params[i].name)) {
112			if (params[i].level < min_level
113			    || params[i].level > max_level)
114				return 0;
115			/* No one handled NULL, so do it here. */
116			if (!val &&
117			    !(params[i].ops->flags & KERNEL_PARAM_OPS_FL_NOARG))
118				return -EINVAL;
119			pr_debug("handling %s with %p\n", param,
120				params[i].ops->set);
121			mutex_lock(&param_lock);
122			param_check_unsafe(&params[i]);
123			err = params[i].ops->set(val, &params[i]);
124			mutex_unlock(&param_lock);
125			return err;
126		}
127	}
128
129	if (handle_unknown) {
130		pr_debug("doing %s: %s='%s'\n", doing, param, val);
131		return handle_unknown(param, val, doing);
132	}
133
134	pr_debug("Unknown argument '%s'\n", param);
135	return -ENOENT;
136}
137
138/* You can use " around spaces, but can't escape ". */
139/* Hyphens and underscores equivalent in parameter names. */
140static char *next_arg(char *args, char **param, char **val)
141{
142	unsigned int i, equals = 0;
143	int in_quote = 0, quoted = 0;
144	char *next;
145
146	if (*args == '"') {
147		args++;
148		in_quote = 1;
149		quoted = 1;
150	}
151
152	for (i = 0; args[i]; i++) {
153		if (isspace(args[i]) && !in_quote)
154			break;
155		if (equals == 0) {
156			if (args[i] == '=')
157				equals = i;
158		}
159		if (args[i] == '"')
160			in_quote = !in_quote;
161	}
162
163	*param = args;
164	if (!equals)
165		*val = NULL;
166	else {
167		args[equals] = '\0';
168		*val = args + equals + 1;
169
170		/* Don't include quotes in value. */
171		if (**val == '"') {
172			(*val)++;
173			if (args[i-1] == '"')
174				args[i-1] = '\0';
175		}
176	}
177	if (quoted && args[i-1] == '"')
178		args[i-1] = '\0';
179
180	if (args[i]) {
181		args[i] = '\0';
182		next = args + i + 1;
183	} else
184		next = args + i;
185
186	/* Chew up trailing spaces. */
187	return skip_spaces(next);
188}
189
190/* Args looks like "foo=bar,bar2 baz=fuz wiz". */
191char *parse_args(const char *doing,
192		 char *args,
193		 const struct kernel_param *params,
194		 unsigned num,
195		 s16 min_level,
196		 s16 max_level,
197		 int (*unknown)(char *param, char *val, const char *doing))
198{
199	char *param, *val;
200
201	/* Chew leading spaces */
202	args = skip_spaces(args);
203
204	if (*args)
205		pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
206
207	while (*args) {
208		int ret;
209		int irq_was_disabled;
210
211		args = next_arg(args, &param, &val);
212		/* Stop at -- */
213		if (!val && strcmp(param, "--") == 0)
214			return args;
215		irq_was_disabled = irqs_disabled();
216		ret = parse_one(param, val, doing, params, num,
217				min_level, max_level, unknown);
218		if (irq_was_disabled && !irqs_disabled())
219			pr_warn("%s: option '%s' enabled irq's!\n",
220				doing, param);
221
222		switch (ret) {
223		case -ENOENT:
224			pr_err("%s: Unknown parameter `%s'\n", doing, param);
225			return ERR_PTR(ret);
226		case -ENOSPC:
227			pr_err("%s: `%s' too large for parameter `%s'\n",
228			       doing, val ?: "", param);
229			return ERR_PTR(ret);
230		case 0:
231			break;
232		default:
233			pr_err("%s: `%s' invalid for parameter `%s'\n",
234			       doing, val ?: "", param);
235			return ERR_PTR(ret);
236		}
237	}
238
239	/* All parsed OK. */
240	return NULL;
241}
242
243/* Lazy bastard, eh? */
244#define STANDARD_PARAM_DEF(name, type, format, strtolfn)      		\
245	int param_set_##name(const char *val, const struct kernel_param *kp) \
246	{								\
247		return strtolfn(val, 0, (type *)kp->arg);		\
248	}								\
249	int param_get_##name(char *buffer, const struct kernel_param *kp) \
250	{								\
251		return scnprintf(buffer, PAGE_SIZE, format,		\
252				*((type *)kp->arg));			\
253	}								\
254	struct kernel_param_ops param_ops_##name = {			\
255		.set = param_set_##name,				\
256		.get = param_get_##name,				\
257	};								\
258	EXPORT_SYMBOL(param_set_##name);				\
259	EXPORT_SYMBOL(param_get_##name);				\
260	EXPORT_SYMBOL(param_ops_##name)
261
262
263STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", kstrtou8);
264STANDARD_PARAM_DEF(short, short, "%hi", kstrtos16);
265STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", kstrtou16);
266STANDARD_PARAM_DEF(int, int, "%i", kstrtoint);
267STANDARD_PARAM_DEF(uint, unsigned int, "%u", kstrtouint);
268STANDARD_PARAM_DEF(long, long, "%li", kstrtol);
269STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", kstrtoul);
270STANDARD_PARAM_DEF(ullong, unsigned long long, "%llu", kstrtoull);
271
272int param_set_charp(const char *val, const struct kernel_param *kp)
273{
274	if (strlen(val) > 1024) {
275		pr_err("%s: string parameter too long\n", kp->name);
276		return -ENOSPC;
277	}
278
279	maybe_kfree_parameter(*(char **)kp->arg);
280
281	/* This is a hack.  We can't kmalloc in early boot, and we
282	 * don't need to; this mangled commandline is preserved. */
283	if (slab_is_available()) {
284		*(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
285		if (!*(char **)kp->arg)
286			return -ENOMEM;
287		strcpy(*(char **)kp->arg, val);
288	} else
289		*(const char **)kp->arg = val;
290
291	return 0;
292}
293EXPORT_SYMBOL(param_set_charp);
294
295int param_get_charp(char *buffer, const struct kernel_param *kp)
296{
297	return scnprintf(buffer, PAGE_SIZE, "%s", *((char **)kp->arg));
298}
299EXPORT_SYMBOL(param_get_charp);
300
301static void param_free_charp(void *arg)
302{
303	maybe_kfree_parameter(*((char **)arg));
304}
305
306struct kernel_param_ops param_ops_charp = {
307	.set = param_set_charp,
308	.get = param_get_charp,
309	.free = param_free_charp,
310};
311EXPORT_SYMBOL(param_ops_charp);
312
313/* Actually could be a bool or an int, for historical reasons. */
314int param_set_bool(const char *val, const struct kernel_param *kp)
315{
316	/* No equals means "set"... */
317	if (!val) val = "1";
318
319	/* One of =[yYnN01] */
320	return strtobool(val, kp->arg);
321}
322EXPORT_SYMBOL(param_set_bool);
323
324int param_get_bool(char *buffer, const struct kernel_param *kp)
325{
326	/* Y and N chosen as being relatively non-coder friendly */
327	return sprintf(buffer, "%c", *(bool *)kp->arg ? 'Y' : 'N');
328}
329EXPORT_SYMBOL(param_get_bool);
330
331struct kernel_param_ops param_ops_bool = {
332	.flags = KERNEL_PARAM_OPS_FL_NOARG,
333	.set = param_set_bool,
334	.get = param_get_bool,
335};
336EXPORT_SYMBOL(param_ops_bool);
337
338/* This one must be bool. */
339int param_set_invbool(const char *val, const struct kernel_param *kp)
340{
341	int ret;
342	bool boolval;
343	struct kernel_param dummy;
344
345	dummy.arg = &boolval;
346	ret = param_set_bool(val, &dummy);
347	if (ret == 0)
348		*(bool *)kp->arg = !boolval;
349	return ret;
350}
351EXPORT_SYMBOL(param_set_invbool);
352
353int param_get_invbool(char *buffer, const struct kernel_param *kp)
354{
355	return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
356}
357EXPORT_SYMBOL(param_get_invbool);
358
359struct kernel_param_ops param_ops_invbool = {
360	.set = param_set_invbool,
361	.get = param_get_invbool,
362};
363EXPORT_SYMBOL(param_ops_invbool);
364
365int param_set_bint(const char *val, const struct kernel_param *kp)
366{
367	struct kernel_param boolkp;
368	bool v;
369	int ret;
370
371	/* Match bool exactly, by re-using it. */
372	boolkp = *kp;
373	boolkp.arg = &v;
374
375	ret = param_set_bool(val, &boolkp);
376	if (ret == 0)
377		*(int *)kp->arg = v;
378	return ret;
379}
380EXPORT_SYMBOL(param_set_bint);
381
382struct kernel_param_ops param_ops_bint = {
383	.flags = KERNEL_PARAM_OPS_FL_NOARG,
384	.set = param_set_bint,
385	.get = param_get_int,
386};
387EXPORT_SYMBOL(param_ops_bint);
388
389/* We break the rule and mangle the string. */
390static int param_array(const char *name,
391		       const char *val,
392		       unsigned int min, unsigned int max,
393		       void *elem, int elemsize,
394		       int (*set)(const char *, const struct kernel_param *kp),
395		       s16 level,
396		       unsigned int *num)
397{
398	int ret;
399	struct kernel_param kp;
400	char save;
401
402	/* Get the name right for errors. */
403	kp.name = name;
404	kp.arg = elem;
405	kp.level = level;
406
407	*num = 0;
408	/* We expect a comma-separated list of values. */
409	do {
410		int len;
411
412		if (*num == max) {
413			pr_err("%s: can only take %i arguments\n", name, max);
414			return -EINVAL;
415		}
416		len = strcspn(val, ",");
417
418		/* nul-terminate and parse */
419		save = val[len];
420		((char *)val)[len] = '\0';
421		BUG_ON(!mutex_is_locked(&param_lock));
422		ret = set(val, &kp);
423
424		if (ret != 0)
425			return ret;
426		kp.arg += elemsize;
427		val += len+1;
428		(*num)++;
429	} while (save == ',');
430
431	if (*num < min) {
432		pr_err("%s: needs at least %i arguments\n", name, min);
433		return -EINVAL;
434	}
435	return 0;
436}
437
438static int param_array_set(const char *val, const struct kernel_param *kp)
439{
440	const struct kparam_array *arr = kp->arr;
441	unsigned int temp_num;
442
443	return param_array(kp->name, val, 1, arr->max, arr->elem,
444			   arr->elemsize, arr->ops->set, kp->level,
445			   arr->num ?: &temp_num);
446}
447
448static int param_array_get(char *buffer, const struct kernel_param *kp)
449{
450	int i, off, ret;
451	const struct kparam_array *arr = kp->arr;
452	struct kernel_param p;
453
454	p = *kp;
455	for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
456		if (i)
457			buffer[off++] = ',';
458		p.arg = arr->elem + arr->elemsize * i;
459		BUG_ON(!mutex_is_locked(&param_lock));
460		ret = arr->ops->get(buffer + off, &p);
461		if (ret < 0)
462			return ret;
463		off += ret;
464	}
465	buffer[off] = '\0';
466	return off;
467}
468
469static void param_array_free(void *arg)
470{
471	unsigned int i;
472	const struct kparam_array *arr = arg;
473
474	if (arr->ops->free)
475		for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
476			arr->ops->free(arr->elem + arr->elemsize * i);
477}
478
479struct kernel_param_ops param_array_ops = {
480	.set = param_array_set,
481	.get = param_array_get,
482	.free = param_array_free,
483};
484EXPORT_SYMBOL(param_array_ops);
485
486int param_set_copystring(const char *val, const struct kernel_param *kp)
487{
488	const struct kparam_string *kps = kp->str;
489
490	if (strlen(val)+1 > kps->maxlen) {
491		pr_err("%s: string doesn't fit in %u chars.\n",
492		       kp->name, kps->maxlen-1);
493		return -ENOSPC;
494	}
495	strcpy(kps->string, val);
496	return 0;
497}
498EXPORT_SYMBOL(param_set_copystring);
499
500int param_get_string(char *buffer, const struct kernel_param *kp)
501{
502	const struct kparam_string *kps = kp->str;
503	return strlcpy(buffer, kps->string, kps->maxlen);
504}
505EXPORT_SYMBOL(param_get_string);
506
507struct kernel_param_ops param_ops_string = {
508	.set = param_set_copystring,
509	.get = param_get_string,
510};
511EXPORT_SYMBOL(param_ops_string);
512
513/* sysfs output in /sys/modules/XYZ/parameters/ */
514#define to_module_attr(n) container_of(n, struct module_attribute, attr)
515#define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
516
517struct param_attribute
518{
519	struct module_attribute mattr;
520	const struct kernel_param *param;
521};
522
523struct module_param_attrs
524{
525	unsigned int num;
526	struct attribute_group grp;
527	struct param_attribute attrs[0];
528};
529
530#ifdef CONFIG_SYSFS
531#define to_param_attr(n) container_of(n, struct param_attribute, mattr)
532
533static ssize_t param_attr_show(struct module_attribute *mattr,
534			       struct module_kobject *mk, char *buf)
535{
536	int count;
537	struct param_attribute *attribute = to_param_attr(mattr);
538
539	if (!attribute->param->ops->get)
540		return -EPERM;
541
542	mutex_lock(&param_lock);
543	count = attribute->param->ops->get(buf, attribute->param);
544	mutex_unlock(&param_lock);
545	if (count > 0) {
546		strcat(buf, "\n");
547		++count;
548	}
549	return count;
550}
551
552/* sysfs always hands a nul-terminated string in buf.  We rely on that. */
553static ssize_t param_attr_store(struct module_attribute *mattr,
554				struct module_kobject *km,
555				const char *buf, size_t len)
556{
557 	int err;
558	struct param_attribute *attribute = to_param_attr(mattr);
559
560	if (!attribute->param->ops->set)
561		return -EPERM;
562
563	mutex_lock(&param_lock);
564	param_check_unsafe(attribute->param);
565	err = attribute->param->ops->set(buf, attribute->param);
566	mutex_unlock(&param_lock);
567	if (!err)
568		return len;
569	return err;
570}
571#endif
572
573#ifdef CONFIG_MODULES
574#define __modinit
575#else
576#define __modinit __init
577#endif
578
579#ifdef CONFIG_SYSFS
580void __kernel_param_lock(void)
581{
582	mutex_lock(&param_lock);
583}
584EXPORT_SYMBOL(__kernel_param_lock);
585
586void __kernel_param_unlock(void)
587{
588	mutex_unlock(&param_lock);
589}
590EXPORT_SYMBOL(__kernel_param_unlock);
591
592/*
593 * add_sysfs_param - add a parameter to sysfs
594 * @mk: struct module_kobject
595 * @kparam: the actual parameter definition to add to sysfs
596 * @name: name of parameter
597 *
598 * Create a kobject if for a (per-module) parameter if mp NULL, and
599 * create file in sysfs.  Returns an error on out of memory.  Always cleans up
600 * if there's an error.
601 */
602static __modinit int add_sysfs_param(struct module_kobject *mk,
603				     const struct kernel_param *kp,
604				     const char *name)
605{
606	struct module_param_attrs *new_mp;
607	struct attribute **new_attrs;
608	unsigned int i;
609
610	/* We don't bother calling this with invisible parameters. */
611	BUG_ON(!kp->perm);
612
613	if (!mk->mp) {
614		/* First allocation. */
615		mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL);
616		if (!mk->mp)
617			return -ENOMEM;
618		mk->mp->grp.name = "parameters";
619		/* NULL-terminated attribute array. */
620		mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]),
621					    GFP_KERNEL);
622		/* Caller will cleanup via free_module_param_attrs */
623		if (!mk->mp->grp.attrs)
624			return -ENOMEM;
625	}
626
627	/* Enlarge allocations. */
628	new_mp = krealloc(mk->mp,
629			  sizeof(*mk->mp) +
630			  sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1),
631			  GFP_KERNEL);
632	if (!new_mp)
633		return -ENOMEM;
634	mk->mp = new_mp;
635
636	/* Extra pointer for NULL terminator */
637	new_attrs = krealloc(mk->mp->grp.attrs,
638			     sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2),
639			     GFP_KERNEL);
640	if (!new_attrs)
641		return -ENOMEM;
642	mk->mp->grp.attrs = new_attrs;
643
644	/* Tack new one on the end. */
645	memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0]));
646	sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr);
647	mk->mp->attrs[mk->mp->num].param = kp;
648	mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show;
649	/* Do not allow runtime DAC changes to make param writable. */
650	if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0)
651		mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store;
652	else
653		mk->mp->attrs[mk->mp->num].mattr.store = NULL;
654	mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name;
655	mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm;
656	mk->mp->num++;
657
658	/* Fix up all the pointers, since krealloc can move us */
659	for (i = 0; i < mk->mp->num; i++)
660		mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr;
661	mk->mp->grp.attrs[mk->mp->num] = NULL;
662	return 0;
663}
664
665#ifdef CONFIG_MODULES
666static void free_module_param_attrs(struct module_kobject *mk)
667{
668	if (mk->mp)
669		kfree(mk->mp->grp.attrs);
670	kfree(mk->mp);
671	mk->mp = NULL;
672}
673
674/*
675 * module_param_sysfs_setup - setup sysfs support for one module
676 * @mod: module
677 * @kparam: module parameters (array)
678 * @num_params: number of module parameters
679 *
680 * Adds sysfs entries for module parameters under
681 * /sys/module/[mod->name]/parameters/
682 */
683int module_param_sysfs_setup(struct module *mod,
684			     const struct kernel_param *kparam,
685			     unsigned int num_params)
686{
687	int i, err;
688	bool params = false;
689
690	for (i = 0; i < num_params; i++) {
691		if (kparam[i].perm == 0)
692			continue;
693		err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
694		if (err) {
695			free_module_param_attrs(&mod->mkobj);
696			return err;
697		}
698		params = true;
699	}
700
701	if (!params)
702		return 0;
703
704	/* Create the param group. */
705	err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
706	if (err)
707		free_module_param_attrs(&mod->mkobj);
708	return err;
709}
710
711/*
712 * module_param_sysfs_remove - remove sysfs support for one module
713 * @mod: module
714 *
715 * Remove sysfs entries for module parameters and the corresponding
716 * kobject.
717 */
718void module_param_sysfs_remove(struct module *mod)
719{
720	if (mod->mkobj.mp) {
721		sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
722		/* We are positive that no one is using any param
723		 * attrs at this point.  Deallocate immediately. */
724		free_module_param_attrs(&mod->mkobj);
725	}
726}
727#endif
728
729void destroy_params(const struct kernel_param *params, unsigned num)
730{
731	unsigned int i;
732
733	for (i = 0; i < num; i++)
734		if (params[i].ops->free)
735			params[i].ops->free(params[i].arg);
736}
737
738static struct module_kobject * __init locate_module_kobject(const char *name)
739{
740	struct module_kobject *mk;
741	struct kobject *kobj;
742	int err;
743
744	kobj = kset_find_obj(module_kset, name);
745	if (kobj) {
746		mk = to_module_kobject(kobj);
747	} else {
748		mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
749		BUG_ON(!mk);
750
751		mk->mod = THIS_MODULE;
752		mk->kobj.kset = module_kset;
753		err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
754					   "%s", name);
755#ifdef CONFIG_MODULES
756		if (!err)
757			err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
758#endif
759		if (err) {
760			kobject_put(&mk->kobj);
761			pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
762				name, err);
763			return NULL;
764		}
765
766		/* So that we hold reference in both cases. */
767		kobject_get(&mk->kobj);
768	}
769
770	return mk;
771}
772
773static void __init kernel_add_sysfs_param(const char *name,
774					  const struct kernel_param *kparam,
775					  unsigned int name_skip)
776{
777	struct module_kobject *mk;
778	int err;
779
780	mk = locate_module_kobject(name);
781	if (!mk)
782		return;
783
784	/* We need to remove old parameters before adding more. */
785	if (mk->mp)
786		sysfs_remove_group(&mk->kobj, &mk->mp->grp);
787
788	/* These should not fail at boot. */
789	err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
790	BUG_ON(err);
791	err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
792	BUG_ON(err);
793	kobject_uevent(&mk->kobj, KOBJ_ADD);
794	kobject_put(&mk->kobj);
795}
796
797/*
798 * param_sysfs_builtin - add sysfs parameters for built-in modules
799 *
800 * Add module_parameters to sysfs for "modules" built into the kernel.
801 *
802 * The "module" name (KBUILD_MODNAME) is stored before a dot, the
803 * "parameter" name is stored behind a dot in kernel_param->name. So,
804 * extract the "module" name for all built-in kernel_param-eters,
805 * and for all who have the same, call kernel_add_sysfs_param.
806 */
807static void __init param_sysfs_builtin(void)
808{
809	const struct kernel_param *kp;
810	unsigned int name_len;
811	char modname[MODULE_NAME_LEN];
812
813	for (kp = __start___param; kp < __stop___param; kp++) {
814		char *dot;
815
816		if (kp->perm == 0)
817			continue;
818
819		dot = strchr(kp->name, '.');
820		if (!dot) {
821			/* This happens for core_param() */
822			strcpy(modname, "kernel");
823			name_len = 0;
824		} else {
825			name_len = dot - kp->name + 1;
826			strlcpy(modname, kp->name, name_len);
827		}
828		kernel_add_sysfs_param(modname, kp, name_len);
829	}
830}
831
832ssize_t __modver_version_show(struct module_attribute *mattr,
833			      struct module_kobject *mk, char *buf)
834{
835	struct module_version_attribute *vattr =
836		container_of(mattr, struct module_version_attribute, mattr);
837
838	return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
839}
840
841extern const struct module_version_attribute *__start___modver[];
842extern const struct module_version_attribute *__stop___modver[];
843
844static void __init version_sysfs_builtin(void)
845{
846	const struct module_version_attribute **p;
847	struct module_kobject *mk;
848	int err;
849
850	for (p = __start___modver; p < __stop___modver; p++) {
851		const struct module_version_attribute *vattr = *p;
852
853		mk = locate_module_kobject(vattr->module_name);
854		if (mk) {
855			err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
856			kobject_uevent(&mk->kobj, KOBJ_ADD);
857			kobject_put(&mk->kobj);
858		}
859	}
860}
861
862/* module-related sysfs stuff */
863
864static ssize_t module_attr_show(struct kobject *kobj,
865				struct attribute *attr,
866				char *buf)
867{
868	struct module_attribute *attribute;
869	struct module_kobject *mk;
870	int ret;
871
872	attribute = to_module_attr(attr);
873	mk = to_module_kobject(kobj);
874
875	if (!attribute->show)
876		return -EIO;
877
878	ret = attribute->show(attribute, mk, buf);
879
880	return ret;
881}
882
883static ssize_t module_attr_store(struct kobject *kobj,
884				struct attribute *attr,
885				const char *buf, size_t len)
886{
887	struct module_attribute *attribute;
888	struct module_kobject *mk;
889	int ret;
890
891	attribute = to_module_attr(attr);
892	mk = to_module_kobject(kobj);
893
894	if (!attribute->store)
895		return -EIO;
896
897	ret = attribute->store(attribute, mk, buf, len);
898
899	return ret;
900}
901
902static const struct sysfs_ops module_sysfs_ops = {
903	.show = module_attr_show,
904	.store = module_attr_store,
905};
906
907static int uevent_filter(struct kset *kset, struct kobject *kobj)
908{
909	struct kobj_type *ktype = get_ktype(kobj);
910
911	if (ktype == &module_ktype)
912		return 1;
913	return 0;
914}
915
916static const struct kset_uevent_ops module_uevent_ops = {
917	.filter = uevent_filter,
918};
919
920struct kset *module_kset;
921int module_sysfs_initialized;
922
923static void module_kobj_release(struct kobject *kobj)
924{
925	struct module_kobject *mk = to_module_kobject(kobj);
926	complete(mk->kobj_completion);
927}
928
929struct kobj_type module_ktype = {
930	.release   =	module_kobj_release,
931	.sysfs_ops =	&module_sysfs_ops,
932};
933
934/*
935 * param_sysfs_init - wrapper for built-in params support
936 */
937static int __init param_sysfs_init(void)
938{
939	module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
940	if (!module_kset) {
941		printk(KERN_WARNING "%s (%d): error creating kset\n",
942			__FILE__, __LINE__);
943		return -ENOMEM;
944	}
945	module_sysfs_initialized = 1;
946
947	version_sysfs_builtin();
948	param_sysfs_builtin();
949
950	return 0;
951}
952subsys_initcall(param_sysfs_init);
953
954#endif /* CONFIG_SYSFS */
955