Linux Audio

Check our new training course

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