Root/kernel/params.c

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/moduleparam.h>
19#include <linux/kernel.h>
20#include <linux/string.h>
21#include <linux/errno.h>
22#include <linux/module.h>
23#include <linux/device.h>
24#include <linux/err.h>
25#include <linux/slab.h>
26#include <linux/ctype.h>
27
28#if 0
29#define DEBUGP printk
30#else
31#define DEBUGP(fmt, a...)
32#endif
33
34/* Protects all parameters, and incidentally kmalloced_param list. */
35static DEFINE_MUTEX(param_lock);
36
37/* This just allows us to keep track of which parameters are kmalloced. */
38struct kmalloced_param {
39    struct list_head list;
40    char val[];
41};
42static LIST_HEAD(kmalloced_params);
43
44static void *kmalloc_parameter(unsigned int size)
45{
46    struct kmalloced_param *p;
47
48    p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
49    if (!p)
50        return NULL;
51
52    list_add(&p->list, &kmalloced_params);
53    return p->val;
54}
55
56/* Does nothing if parameter wasn't kmalloced above. */
57static void maybe_kfree_parameter(void *param)
58{
59    struct kmalloced_param *p;
60
61    list_for_each_entry(p, &kmalloced_params, list) {
62        if (p->val == param) {
63            list_del(&p->list);
64            kfree(p);
65            break;
66        }
67    }
68}
69
70static inline char dash2underscore(char c)
71{
72    if (c == '-')
73        return '_';
74    return c;
75}
76
77static inline int parameq(const char *input, const char *paramname)
78{
79    unsigned int i;
80    for (i = 0; dash2underscore(input[i]) == paramname[i]; i++)
81        if (input[i] == '\0')
82            return 1;
83    return 0;
84}
85
86static int parse_one(char *param,
87             char *val,
88             const struct kernel_param *params,
89             unsigned num_params,
90             int (*handle_unknown)(char *param, char *val))
91{
92    unsigned int i;
93    int err;
94
95    /* Find parameter */
96    for (i = 0; i < num_params; i++) {
97        if (parameq(param, params[i].name)) {
98            /* Noone handled NULL, so do it here. */
99            if (!val && params[i].ops->set != param_set_bool)
100                return -EINVAL;
101            DEBUGP("They are equal! Calling %p\n",
102                   params[i].ops->set);
103            mutex_lock(&param_lock);
104            err = params[i].ops->set(val, &params[i]);
105            mutex_unlock(&param_lock);
106            return err;
107        }
108    }
109
110    if (handle_unknown) {
111        DEBUGP("Unknown argument: calling %p\n", handle_unknown);
112        return handle_unknown(param, val);
113    }
114
115    DEBUGP("Unknown argument `%s'\n", param);
116    return -ENOENT;
117}
118
119/* You can use " around spaces, but can't escape ". */
120/* Hyphens and underscores equivalent in parameter names. */
121static char *next_arg(char *args, char **param, char **val)
122{
123    unsigned int i, equals = 0;
124    int in_quote = 0, quoted = 0;
125    char *next;
126
127    if (*args == '"') {
128        args++;
129        in_quote = 1;
130        quoted = 1;
131    }
132
133    for (i = 0; args[i]; i++) {
134        if (isspace(args[i]) && !in_quote)
135            break;
136        if (equals == 0) {
137            if (args[i] == '=')
138                equals = i;
139        }
140        if (args[i] == '"')
141            in_quote = !in_quote;
142    }
143
144    *param = args;
145    if (!equals)
146        *val = NULL;
147    else {
148        args[equals] = '\0';
149        *val = args + equals + 1;
150
151        /* Don't include quotes in value. */
152        if (**val == '"') {
153            (*val)++;
154            if (args[i-1] == '"')
155                args[i-1] = '\0';
156        }
157        if (quoted && args[i-1] == '"')
158            args[i-1] = '\0';
159    }
160
161    if (args[i]) {
162        args[i] = '\0';
163        next = args + i + 1;
164    } else
165        next = args + i;
166
167    /* Chew up trailing spaces. */
168    return skip_spaces(next);
169}
170
171/* Args looks like "foo=bar,bar2 baz=fuz wiz". */
172int parse_args(const char *name,
173           char *args,
174           const struct kernel_param *params,
175           unsigned num,
176           int (*unknown)(char *param, char *val))
177{
178    char *param, *val;
179
180    DEBUGP("Parsing ARGS: %s\n", args);
181
182    /* Chew leading spaces */
183    args = skip_spaces(args);
184
185    while (*args) {
186        int ret;
187        int irq_was_disabled;
188
189        args = next_arg(args, &param, &val);
190        irq_was_disabled = irqs_disabled();
191        ret = parse_one(param, val, params, num, unknown);
192        if (irq_was_disabled && !irqs_disabled()) {
193            printk(KERN_WARNING "parse_args(): option '%s' enabled "
194                    "irq's!\n", param);
195        }
196        switch (ret) {
197        case -ENOENT:
198            printk(KERN_ERR "%s: Unknown parameter `%s'\n",
199                   name, param);
200            return ret;
201        case -ENOSPC:
202            printk(KERN_ERR
203                   "%s: `%s' too large for parameter `%s'\n",
204                   name, val ?: "", param);
205            return ret;
206        case 0:
207            break;
208        default:
209            printk(KERN_ERR
210                   "%s: `%s' invalid for parameter `%s'\n",
211                   name, val ?: "", param);
212            return ret;
213        }
214    }
215
216    /* All parsed OK. */
217    return 0;
218}
219
220/* Lazy bastard, eh? */
221#define STANDARD_PARAM_DEF(name, type, format, tmptype, strtolfn) \
222    int param_set_##name(const char *val, const struct kernel_param *kp) \
223    { \
224        tmptype l; \
225        int ret; \
226                                    \
227        ret = strtolfn(val, 0, &l); \
228        if (ret == -EINVAL || ((type)l != l)) \
229            return -EINVAL; \
230        *((type *)kp->arg) = l; \
231        return 0; \
232    } \
233    int param_get_##name(char *buffer, const struct kernel_param *kp) \
234    { \
235        return sprintf(buffer, format, *((type *)kp->arg)); \
236    } \
237    struct kernel_param_ops param_ops_##name = { \
238        .set = param_set_##name, \
239        .get = param_get_##name, \
240    }; \
241    EXPORT_SYMBOL(param_set_##name); \
242    EXPORT_SYMBOL(param_get_##name); \
243    EXPORT_SYMBOL(param_ops_##name)
244
245
246STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, strict_strtoul);
247STANDARD_PARAM_DEF(short, short, "%hi", long, strict_strtol);
248STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, strict_strtoul);
249STANDARD_PARAM_DEF(int, int, "%i", long, strict_strtol);
250STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, strict_strtoul);
251STANDARD_PARAM_DEF(long, long, "%li", long, strict_strtol);
252STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, strict_strtoul);
253
254int param_set_charp(const char *val, const struct kernel_param *kp)
255{
256    if (strlen(val) > 1024) {
257        printk(KERN_ERR "%s: string parameter too long\n",
258               kp->name);
259        return -ENOSPC;
260    }
261
262    maybe_kfree_parameter(*(char **)kp->arg);
263
264    /* This is a hack. We can't kmalloc in early boot, and we
265     * don't need to; this mangled commandline is preserved. */
266    if (slab_is_available()) {
267        *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
268        if (!*(char **)kp->arg)
269            return -ENOMEM;
270        strcpy(*(char **)kp->arg, val);
271    } else
272        *(const char **)kp->arg = val;
273
274    return 0;
275}
276EXPORT_SYMBOL(param_set_charp);
277
278int param_get_charp(char *buffer, const struct kernel_param *kp)
279{
280    return sprintf(buffer, "%s", *((char **)kp->arg));
281}
282EXPORT_SYMBOL(param_get_charp);
283
284static void param_free_charp(void *arg)
285{
286    maybe_kfree_parameter(*((char **)arg));
287}
288
289struct kernel_param_ops param_ops_charp = {
290    .set = param_set_charp,
291    .get = param_get_charp,
292    .free = param_free_charp,
293};
294EXPORT_SYMBOL(param_ops_charp);
295
296/* Actually could be a bool or an int, for historical reasons. */
297int param_set_bool(const char *val, const struct kernel_param *kp)
298{
299    bool v;
300
301    /* No equals means "set"... */
302    if (!val) val = "1";
303
304    /* One of =[yYnN01] */
305    switch (val[0]) {
306    case 'y': case 'Y': case '1':
307        v = true;
308        break;
309    case 'n': case 'N': case '0':
310        v = false;
311        break;
312    default:
313        return -EINVAL;
314    }
315
316    if (kp->flags & KPARAM_ISBOOL)
317        *(bool *)kp->arg = v;
318    else
319        *(int *)kp->arg = v;
320    return 0;
321}
322EXPORT_SYMBOL(param_set_bool);
323
324int param_get_bool(char *buffer, const struct kernel_param *kp)
325{
326    bool val;
327    if (kp->flags & KPARAM_ISBOOL)
328        val = *(bool *)kp->arg;
329    else
330        val = *(int *)kp->arg;
331
332    /* Y and N chosen as being relatively non-coder friendly */
333    return sprintf(buffer, "%c", val ? 'Y' : 'N');
334}
335EXPORT_SYMBOL(param_get_bool);
336
337struct kernel_param_ops param_ops_bool = {
338    .set = param_set_bool,
339    .get = param_get_bool,
340};
341EXPORT_SYMBOL(param_ops_bool);
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    dummy.flags = KPARAM_ISBOOL;
352    ret = param_set_bool(val, &dummy);
353    if (ret == 0)
354        *(bool *)kp->arg = !boolval;
355    return ret;
356}
357EXPORT_SYMBOL(param_set_invbool);
358
359int param_get_invbool(char *buffer, const struct kernel_param *kp)
360{
361    return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
362}
363EXPORT_SYMBOL(param_get_invbool);
364
365struct kernel_param_ops param_ops_invbool = {
366    .set = param_set_invbool,
367    .get = param_get_invbool,
368};
369EXPORT_SYMBOL(param_ops_invbool);
370
371/* We break the rule and mangle the string. */
372static int param_array(const char *name,
373               const char *val,
374               unsigned int min, unsigned int max,
375               void *elem, int elemsize,
376               int (*set)(const char *, const struct kernel_param *kp),
377               u16 flags,
378               unsigned int *num)
379{
380    int ret;
381    struct kernel_param kp;
382    char save;
383
384    /* Get the name right for errors. */
385    kp.name = name;
386    kp.arg = elem;
387    kp.flags = flags;
388
389    *num = 0;
390    /* We expect a comma-separated list of values. */
391    do {
392        int len;
393
394        if (*num == max) {
395            printk(KERN_ERR "%s: can only take %i arguments\n",
396                   name, max);
397            return -EINVAL;
398        }
399        len = strcspn(val, ",");
400
401        /* nul-terminate and parse */
402        save = val[len];
403        ((char *)val)[len] = '\0';
404        BUG_ON(!mutex_is_locked(&param_lock));
405        ret = set(val, &kp);
406
407        if (ret != 0)
408            return ret;
409        kp.arg += elemsize;
410        val += len+1;
411        (*num)++;
412    } while (save == ',');
413
414    if (*num < min) {
415        printk(KERN_ERR "%s: needs at least %i arguments\n",
416               name, min);
417        return -EINVAL;
418    }
419    return 0;
420}
421
422static int param_array_set(const char *val, const struct kernel_param *kp)
423{
424    const struct kparam_array *arr = kp->arr;
425    unsigned int temp_num;
426
427    return param_array(kp->name, val, 1, arr->max, arr->elem,
428               arr->elemsize, arr->ops->set, kp->flags,
429               arr->num ?: &temp_num);
430}
431
432static int param_array_get(char *buffer, const struct kernel_param *kp)
433{
434    int i, off, ret;
435    const struct kparam_array *arr = kp->arr;
436    struct kernel_param p;
437
438    p = *kp;
439    for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
440        if (i)
441            buffer[off++] = ',';
442        p.arg = arr->elem + arr->elemsize * i;
443        BUG_ON(!mutex_is_locked(&param_lock));
444        ret = arr->ops->get(buffer + off, &p);
445        if (ret < 0)
446            return ret;
447        off += ret;
448    }
449    buffer[off] = '\0';
450    return off;
451}
452
453static void param_array_free(void *arg)
454{
455    unsigned int i;
456    const struct kparam_array *arr = arg;
457
458    if (arr->ops->free)
459        for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
460            arr->ops->free(arr->elem + arr->elemsize * i);
461}
462
463struct kernel_param_ops param_array_ops = {
464    .set = param_array_set,
465    .get = param_array_get,
466    .free = param_array_free,
467};
468EXPORT_SYMBOL(param_array_ops);
469
470int param_set_copystring(const char *val, const struct kernel_param *kp)
471{
472    const struct kparam_string *kps = kp->str;
473
474    if (strlen(val)+1 > kps->maxlen) {
475        printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
476               kp->name, kps->maxlen-1);
477        return -ENOSPC;
478    }
479    strcpy(kps->string, val);
480    return 0;
481}
482EXPORT_SYMBOL(param_set_copystring);
483
484int param_get_string(char *buffer, const struct kernel_param *kp)
485{
486    const struct kparam_string *kps = kp->str;
487    return strlcpy(buffer, kps->string, kps->maxlen);
488}
489EXPORT_SYMBOL(param_get_string);
490
491struct kernel_param_ops param_ops_string = {
492    .set = param_set_copystring,
493    .get = param_get_string,
494};
495EXPORT_SYMBOL(param_ops_string);
496
497/* sysfs output in /sys/modules/XYZ/parameters/ */
498#define to_module_attr(n) container_of(n, struct module_attribute, attr)
499#define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
500
501extern struct kernel_param __start___param[], __stop___param[];
502
503struct param_attribute
504{
505    struct module_attribute mattr;
506    const struct kernel_param *param;
507};
508
509struct module_param_attrs
510{
511    unsigned int num;
512    struct attribute_group grp;
513    struct param_attribute attrs[0];
514};
515
516#ifdef CONFIG_SYSFS
517#define to_param_attr(n) container_of(n, struct param_attribute, mattr)
518
519static ssize_t param_attr_show(struct module_attribute *mattr,
520                   struct module *mod, char *buf)
521{
522    int count;
523    struct param_attribute *attribute = to_param_attr(mattr);
524
525    if (!attribute->param->ops->get)
526        return -EPERM;
527
528    mutex_lock(&param_lock);
529    count = attribute->param->ops->get(buf, attribute->param);
530    mutex_unlock(&param_lock);
531    if (count > 0) {
532        strcat(buf, "\n");
533        ++count;
534    }
535    return count;
536}
537
538/* sysfs always hands a nul-terminated string in buf. We rely on that. */
539static ssize_t param_attr_store(struct module_attribute *mattr,
540                struct module *owner,
541                const char *buf, size_t len)
542{
543     int err;
544    struct param_attribute *attribute = to_param_attr(mattr);
545
546    if (!attribute->param->ops->set)
547        return -EPERM;
548
549    mutex_lock(&param_lock);
550    err = attribute->param->ops->set(buf, attribute->param);
551    mutex_unlock(&param_lock);
552    if (!err)
553        return len;
554    return err;
555}
556#endif
557
558#ifdef CONFIG_MODULES
559#define __modinit
560#else
561#define __modinit __init
562#endif
563
564#ifdef CONFIG_SYSFS
565void __kernel_param_lock(void)
566{
567    mutex_lock(&param_lock);
568}
569EXPORT_SYMBOL(__kernel_param_lock);
570
571void __kernel_param_unlock(void)
572{
573    mutex_unlock(&param_lock);
574}
575EXPORT_SYMBOL(__kernel_param_unlock);
576
577/*
578 * add_sysfs_param - add a parameter to sysfs
579 * @mk: struct module_kobject
580 * @kparam: the actual parameter definition to add to sysfs
581 * @name: name of parameter
582 *
583 * Create a kobject if for a (per-module) parameter if mp NULL, and
584 * create file in sysfs. Returns an error on out of memory. Always cleans up
585 * if there's an error.
586 */
587static __modinit int add_sysfs_param(struct module_kobject *mk,
588                     const struct kernel_param *kp,
589                     const char *name)
590{
591    struct module_param_attrs *new;
592    struct attribute **attrs;
593    int err, num;
594
595    /* We don't bother calling this with invisible parameters. */
596    BUG_ON(!kp->perm);
597
598    if (!mk->mp) {
599        num = 0;
600        attrs = NULL;
601    } else {
602        num = mk->mp->num;
603        attrs = mk->mp->grp.attrs;
604    }
605
606    /* Enlarge. */
607    new = krealloc(mk->mp,
608               sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
609               GFP_KERNEL);
610    if (!new) {
611        kfree(mk->mp);
612        err = -ENOMEM;
613        goto fail;
614    }
615    attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
616    if (!attrs) {
617        err = -ENOMEM;
618        goto fail_free_new;
619    }
620
621    /* Sysfs wants everything zeroed. */
622    memset(new, 0, sizeof(*new));
623    memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
624    memset(&attrs[num], 0, sizeof(attrs[num]));
625    new->grp.name = "parameters";
626    new->grp.attrs = attrs;
627
628    /* Tack new one on the end. */
629    sysfs_attr_init(&new->attrs[num].mattr.attr);
630    new->attrs[num].param = kp;
631    new->attrs[num].mattr.show = param_attr_show;
632    new->attrs[num].mattr.store = param_attr_store;
633    new->attrs[num].mattr.attr.name = (char *)name;
634    new->attrs[num].mattr.attr.mode = kp->perm;
635    new->num = num+1;
636
637    /* Fix up all the pointers, since krealloc can move us */
638    for (num = 0; num < new->num; num++)
639        new->grp.attrs[num] = &new->attrs[num].mattr.attr;
640    new->grp.attrs[num] = NULL;
641
642    mk->mp = new;
643    return 0;
644
645fail_free_new:
646    kfree(new);
647fail:
648    mk->mp = NULL;
649    return err;
650}
651
652#ifdef CONFIG_MODULES
653static void free_module_param_attrs(struct module_kobject *mk)
654{
655    kfree(mk->mp->grp.attrs);
656    kfree(mk->mp);
657    mk->mp = NULL;
658}
659
660/*
661 * module_param_sysfs_setup - setup sysfs support for one module
662 * @mod: module
663 * @kparam: module parameters (array)
664 * @num_params: number of module parameters
665 *
666 * Adds sysfs entries for module parameters under
667 * /sys/module/[mod->name]/parameters/
668 */
669int module_param_sysfs_setup(struct module *mod,
670                 const struct kernel_param *kparam,
671                 unsigned int num_params)
672{
673    int i, err;
674    bool params = false;
675
676    for (i = 0; i < num_params; i++) {
677        if (kparam[i].perm == 0)
678            continue;
679        err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
680        if (err)
681            return err;
682        params = true;
683    }
684
685    if (!params)
686        return 0;
687
688    /* Create the param group. */
689    err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
690    if (err)
691        free_module_param_attrs(&mod->mkobj);
692    return err;
693}
694
695/*
696 * module_param_sysfs_remove - remove sysfs support for one module
697 * @mod: module
698 *
699 * Remove sysfs entries for module parameters and the corresponding
700 * kobject.
701 */
702void module_param_sysfs_remove(struct module *mod)
703{
704    if (mod->mkobj.mp) {
705        sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
706        /* We are positive that no one is using any param
707         * attrs at this point. Deallocate immediately. */
708        free_module_param_attrs(&mod->mkobj);
709    }
710}
711#endif
712
713void destroy_params(const struct kernel_param *params, unsigned num)
714{
715    unsigned int i;
716
717    for (i = 0; i < num; i++)
718        if (params[i].ops->free)
719            params[i].ops->free(params[i].arg);
720}
721
722static void __init kernel_add_sysfs_param(const char *name,
723                      struct kernel_param *kparam,
724                      unsigned int name_skip)
725{
726    struct module_kobject *mk;
727    struct kobject *kobj;
728    int err;
729
730    kobj = kset_find_obj(module_kset, name);
731    if (kobj) {
732        /* We already have one. Remove params so we can add more. */
733        mk = to_module_kobject(kobj);
734        /* We need to remove it before adding parameters. */
735        sysfs_remove_group(&mk->kobj, &mk->mp->grp);
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        if (err) {
745            kobject_put(&mk->kobj);
746            printk(KERN_ERR "Module '%s' failed add to sysfs, "
747                   "error number %d\n", name, err);
748            printk(KERN_ERR "The system will be unstable now.\n");
749            return;
750        }
751        /* So that exit path is even. */
752        kobject_get(&mk->kobj);
753    }
754
755    /* These should not fail at boot. */
756    err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
757    BUG_ON(err);
758    err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
759    BUG_ON(err);
760    kobject_uevent(&mk->kobj, KOBJ_ADD);
761    kobject_put(&mk->kobj);
762}
763
764/*
765 * param_sysfs_builtin - add contents in /sys/parameters for built-in modules
766 *
767 * Add module_parameters to sysfs for "modules" built into the kernel.
768 *
769 * The "module" name (KBUILD_MODNAME) is stored before a dot, the
770 * "parameter" name is stored behind a dot in kernel_param->name. So,
771 * extract the "module" name for all built-in kernel_param-eters,
772 * and for all who have the same, call kernel_add_sysfs_param.
773 */
774static void __init param_sysfs_builtin(void)
775{
776    struct kernel_param *kp;
777    unsigned int name_len;
778    char modname[MODULE_NAME_LEN];
779
780    for (kp = __start___param; kp < __stop___param; kp++) {
781        char *dot;
782
783        if (kp->perm == 0)
784            continue;
785
786        dot = strchr(kp->name, '.');
787        if (!dot) {
788            /* This happens for core_param() */
789            strcpy(modname, "kernel");
790            name_len = 0;
791        } else {
792            name_len = dot - kp->name + 1;
793            strlcpy(modname, kp->name, name_len);
794        }
795        kernel_add_sysfs_param(modname, kp, name_len);
796    }
797}
798
799
800/* module-related sysfs stuff */
801
802static ssize_t module_attr_show(struct kobject *kobj,
803                struct attribute *attr,
804                char *buf)
805{
806    struct module_attribute *attribute;
807    struct module_kobject *mk;
808    int ret;
809
810    attribute = to_module_attr(attr);
811    mk = to_module_kobject(kobj);
812
813    if (!attribute->show)
814        return -EIO;
815
816    ret = attribute->show(attribute, mk->mod, buf);
817
818    return ret;
819}
820
821static ssize_t module_attr_store(struct kobject *kobj,
822                struct attribute *attr,
823                const char *buf, size_t len)
824{
825    struct module_attribute *attribute;
826    struct module_kobject *mk;
827    int ret;
828
829    attribute = to_module_attr(attr);
830    mk = to_module_kobject(kobj);
831
832    if (!attribute->store)
833        return -EIO;
834
835    ret = attribute->store(attribute, mk->mod, buf, len);
836
837    return ret;
838}
839
840static const struct sysfs_ops module_sysfs_ops = {
841    .show = module_attr_show,
842    .store = module_attr_store,
843};
844
845static int uevent_filter(struct kset *kset, struct kobject *kobj)
846{
847    struct kobj_type *ktype = get_ktype(kobj);
848
849    if (ktype == &module_ktype)
850        return 1;
851    return 0;
852}
853
854static const struct kset_uevent_ops module_uevent_ops = {
855    .filter = uevent_filter,
856};
857
858struct kset *module_kset;
859int module_sysfs_initialized;
860
861struct kobj_type module_ktype = {
862    .sysfs_ops = &module_sysfs_ops,
863};
864
865/*
866 * param_sysfs_init - wrapper for built-in params support
867 */
868static int __init param_sysfs_init(void)
869{
870    module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
871    if (!module_kset) {
872        printk(KERN_WARNING "%s (%d): error creating kset\n",
873            __FILE__, __LINE__);
874        return -ENOMEM;
875    }
876    module_sysfs_initialized = 1;
877
878    param_sysfs_builtin();
879
880    return 0;
881}
882subsys_initcall(param_sysfs_init);
883
884#endif /* CONFIG_SYSFS */
885

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