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params.c
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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. */
28 static DEFINE_MUTEX(param_lock);
29 
30 /* This just allows us to keep track of which parameters are kmalloced. */
32  struct list_head list;
33  char val[];
34 };
35 static LIST_HEAD(kmalloced_params);
36 
37 static 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. */
50 static 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 
63 static char dash2underscore(char c)
64 {
65  if (c == '-')
66  return '_';
67  return c;
68 }
69 
70 bool 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 
81 bool parameq(const char *a, const char *b)
82 {
83  return parameqn(a, b, strlen(a)+1);
84 }
85 
86 static 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. */
129 static 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". */
180 int 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 
255 STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, strict_strtoul);
256 STANDARD_PARAM_DEF(short, short, "%hi", long, strict_strtol);
257 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, strict_strtoul);
258 STANDARD_PARAM_DEF(int, int, "%i", long, strict_strtol);
259 STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, strict_strtoul);
260 STANDARD_PARAM_DEF(long, long, "%li", long, strict_strtol);
261 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, strict_strtoul);
262 
263 int 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 }
285 
286 int param_get_charp(char *buffer, const struct kernel_param *kp)
287 {
288  return sprintf(buffer, "%s", *((char **)kp->arg));
289 }
291 
292 static void param_free_charp(void *arg)
293 {
294  maybe_kfree_parameter(*((char **)arg));
295 }
296 
298  .set = param_set_charp,
299  .get = param_get_charp,
300  .free = param_free_charp,
301 };
302 EXPORT_SYMBOL(param_ops_charp);
303 
304 /* Actually could be a bool or an int, for historical reasons. */
305 int 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 }
314 
315 int 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 }
321 
323  .set = param_set_bool,
324  .get = param_get_bool,
325 };
326 EXPORT_SYMBOL(param_ops_bool);
327 
328 /* This one must be bool. */
329 int 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 }
342 
343 int param_get_invbool(char *buffer, const struct kernel_param *kp)
344 {
345  return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
346 }
348 
350  .set = param_set_invbool,
351  .get = param_get_invbool,
352 };
353 EXPORT_SYMBOL(param_ops_invbool);
354 
355 int 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 }
371 
373  .set = param_set_bint,
374  .get = param_get_int,
375 };
376 EXPORT_SYMBOL(param_ops_bint);
377 
378 /* We break the rule and mangle the string. */
379 static 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 
427 static 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 
437 static 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 
458 static 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 
469  .set = param_array_set,
470  .get = param_array_get,
471  .free = param_array_free,
472 };
473 EXPORT_SYMBOL(param_array_ops);
474 
475 int 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 }
488 
489 int 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 }
495 
497  .set = param_set_copystring,
498  .get = param_get_string,
499 };
500 EXPORT_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 
506 extern struct kernel_param __start___param[], __stop___param[];
507 
509 {
511  const struct kernel_param *param;
512 };
513 
515 {
516  unsigned int num;
519 };
520 
521 #ifdef CONFIG_SYSFS
522 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
523 
524 static 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. */
544 static 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
570 void __kernel_param_lock(void)
571 {
572  mutex_lock(&param_lock);
573 }
574 EXPORT_SYMBOL(__kernel_param_lock);
575 
576 void __kernel_param_unlock(void)
577 {
578  mutex_unlock(&param_lock);
579 }
580 EXPORT_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  */
592 static __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 
650 fail_free_new:
651  kfree(new);
652 fail:
653  mk->mp = NULL;
654  return err;
655 }
656 
657 #ifdef CONFIG_MODULES
658 static 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  */
674 int 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  */
707 void 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 
718 void 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 
727 static 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 
762 static 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);
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  */
796 static 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 
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 
830 extern const struct module_version_attribute *__start___modver[];
831 extern const struct module_version_attribute *__stop___modver[];
832 
833 static 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);
846  kobject_put(&mk->kobj);
847  }
848  }
849 }
850 
851 /* module-related sysfs stuff */
852 
853 static 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 
872 static 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 
891 static const struct sysfs_ops module_sysfs_ops = {
892  .show = module_attr_show,
893  .store = module_attr_store,
894 };
895 
896 static 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 
905 static const struct kset_uevent_ops module_uevent_ops = {
906  .filter = uevent_filter,
907 };
908 
909 struct kset *module_kset;
910 int module_sysfs_initialized;
911 
912 struct kobj_type module_ktype = {
913  .sysfs_ops = &module_sysfs_ops,
914 };
915 
916 /*
917  * param_sysfs_init - wrapper for built-in params support
918  */
919 static 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 }
934 subsys_initcall(param_sysfs_init);
935 
936 #endif /* CONFIG_SYSFS */