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. */
  35 static DEFINE_MUTEX(param_lock);
  36
  37 /* This just allows us to keep track of which parameters are kmalloced. */
  38 struct kmalloced_param {
  39         struct list_head list;
  40         char val[];
  41 };
  42 static LIST_HEAD(kmalloced_params);
  43
  44 static 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. */
  57 static 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
  70 static inline char dash2underscore(char c)
  71 {
  72         if (c == '-')
  73                 return '_';
  74         return c;
  75 }
  76
  77 static 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
  86 static 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                         /* No one 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. */
 121 static 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". */
 172 int 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 < 0 || ((type)l != l))                          \
 229                         return ret < 0 ? ret : -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
 246 STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, strict_strtoul);
 247 STANDARD_PARAM_DEF(short, short, "%hi", long, strict_strtol);
 248 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, strict_strtoul);
 249 STANDARD_PARAM_DEF(int, int, "%i", long, strict_strtol);
 250 STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, strict_strtoul);
 251 STANDARD_PARAM_DEF(long, long, "%li", long, strict_strtol);
 252 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, strict_strtoul);
 253
 254 int 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 }
 276 EXPORT_SYMBOL(param_set_charp);
 277
 278 int param_get_charp(char *buffer, const struct kernel_param *kp)
 279 {
 280         return sprintf(buffer, "%s", *((char **)kp->arg));
 281 }
 282 EXPORT_SYMBOL(param_get_charp);
 283
 284 static void param_free_charp(void *arg)
 285 {
 286         maybe_kfree_parameter(*((char **)arg));
 287 }
 288
 289 struct kernel_param_ops param_ops_charp = {
 290         .set = param_set_charp,
 291         .get = param_get_charp,
 292         .free = param_free_charp,
 293 };
 294 EXPORT_SYMBOL(param_ops_charp);
 295
 296 /* Actually could be a bool or an int, for historical reasons. */
 297 int param_set_bool(const char *val, const struct kernel_param *kp)
 298 {
 299         bool v;
 300         int ret;
 301
 302         /* No equals means "set"... */
 303         if (!val) val = "1";
 304
 305         /* One of =[yYnN01] */
 306         ret = strtobool(val, &v);
 307         if (ret)
 308                 return ret;
 309
 310         if (kp->flags & KPARAM_ISBOOL)
 311                 *(bool *)kp->arg = v;
 312         else
 313                 *(int *)kp->arg = v;
 314         return 0;
 315 }
 316 EXPORT_SYMBOL(param_set_bool);
 317
 318 int param_get_bool(char *buffer, const struct kernel_param *kp)
 319 {
 320         bool val;
 321         if (kp->flags & KPARAM_ISBOOL)
 322                 val = *(bool *)kp->arg;
 323         else
 324                 val = *(int *)kp->arg;
 325
 326         /* Y and N chosen as being relatively non-coder friendly */
 327         return sprintf(buffer, "%c", val ? 'Y' : 'N');
 328 }
 329 EXPORT_SYMBOL(param_get_bool);
 330
 331 struct kernel_param_ops param_ops_bool = {
 332         .set = param_set_bool,
 333         .get = param_get_bool,
 334 };
 335 EXPORT_SYMBOL(param_ops_bool);
 336
 337 /* This one must be bool. */
 338 int param_set_invbool(const char *val, const struct kernel_param *kp)
 339 {
 340         int ret;
 341         bool boolval;
 342         struct kernel_param dummy;
 343
 344         dummy.arg = &boolval;
 345         dummy.flags = KPARAM_ISBOOL;
 346         ret = param_set_bool(val, &dummy);
 347         if (ret == 0)
 348                 *(bool *)kp->arg = !boolval;
 349         return ret;
 350 }
 351 EXPORT_SYMBOL(param_set_invbool);
 352
 353 int param_get_invbool(char *buffer, const struct kernel_param *kp)
 354 {
 355         return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
 356 }
 357 EXPORT_SYMBOL(param_get_invbool);
 358
 359 struct kernel_param_ops param_ops_invbool = {
 360         .set = param_set_invbool,
 361         .get = param_get_invbool,
 362 };
 363 EXPORT_SYMBOL(param_ops_invbool);
 364
 365 /* We break the rule and mangle the string. */
 366 static int param_array(const char *name,
 367                        const char *val,
 368                        unsigned int min, unsigned int max,
 369                        void *elem, int elemsize,
 370                        int (*set)(const char *, const struct kernel_param *kp),
 371                        u16 flags,
 372                        unsigned int *num)
 373 {
 374         int ret;
 375         struct kernel_param kp;
 376         char save;
 377
 378         /* Get the name right for errors. */
 379         kp.name = name;
 380         kp.arg = elem;
 381         kp.flags = flags;
 382
 383         *num = 0;
 384         /* We expect a comma-separated list of values. */
 385         do {
 386                 int len;
 387
 388                 if (*num == max) {
 389                         printk(KERN_ERR "%s: can only take %i arguments\n",
 390                                name, max);
 391                         return -EINVAL;
 392                 }
 393                 len = strcspn(val, ",");
 394
 395                 /* nul-terminate and parse */
 396                 save = val[len];
 397                 ((char *)val)[len] = '\0';
 398                 BUG_ON(!mutex_is_locked(&param_lock));
 399                 ret = set(val, &kp);
 400
 401                 if (ret != 0)
 402                         return ret;
 403                 kp.arg += elemsize;
 404                 val += len+1;
 405                 (*num)++;
 406         } while (save == ',');
 407
 408         if (*num < min) {
 409                 printk(KERN_ERR "%s: needs at least %i arguments\n",
 410                        name, min);
 411                 return -EINVAL;
 412         }
 413         return 0;
 414 }
 415
 416 static int param_array_set(const char *val, const struct kernel_param *kp)
 417 {
 418         const struct kparam_array *arr = kp->arr;
 419         unsigned int temp_num;
 420
 421         return param_array(kp->name, val, 1, arr->max, arr->elem,
 422                            arr->elemsize, arr->ops->set, kp->flags,
 423                            arr->num ?: &temp_num);
 424 }
 425
 426 static int param_array_get(char *buffer, const struct kernel_param *kp)
 427 {
 428         int i, off, ret;
 429         const struct kparam_array *arr = kp->arr;
 430         struct kernel_param p;
 431
 432         p = *kp;
 433         for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 434                 if (i)
 435                         buffer[off++] = ',';
 436                 p.arg = arr->elem + arr->elemsize * i;
 437                 BUG_ON(!mutex_is_locked(&param_lock));
 438                 ret = arr->ops->get(buffer + off, &p);
 439                 if (ret < 0)
 440                         return ret;
 441                 off += ret;
 442         }
 443         buffer[off] = '\0';
 444         return off;
 445 }
 446
 447 static void param_array_free(void *arg)
 448 {
 449         unsigned int i;
 450         const struct kparam_array *arr = arg;
 451
 452         if (arr->ops->free)
 453                 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 454                         arr->ops->free(arr->elem + arr->elemsize * i);
 455 }
 456
 457 struct kernel_param_ops param_array_ops = {
 458         .set = param_array_set,
 459         .get = param_array_get,
 460         .free = param_array_free,
 461 };
 462 EXPORT_SYMBOL(param_array_ops);
 463
 464 int param_set_copystring(const char *val, const struct kernel_param *kp)
 465 {
 466         const struct kparam_string *kps = kp->str;
 467
 468         if (strlen(val)+1 > kps->maxlen) {
 469                 printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
 470                        kp->name, kps->maxlen-1);
 471                 return -ENOSPC;
 472         }
 473         strcpy(kps->string, val);
 474         return 0;
 475 }
 476 EXPORT_SYMBOL(param_set_copystring);
 477
 478 int param_get_string(char *buffer, const struct kernel_param *kp)
 479 {
 480         const struct kparam_string *kps = kp->str;
 481         return strlcpy(buffer, kps->string, kps->maxlen);
 482 }
 483 EXPORT_SYMBOL(param_get_string);
 484
 485 struct kernel_param_ops param_ops_string = {
 486         .set = param_set_copystring,
 487         .get = param_get_string,
 488 };
 489 EXPORT_SYMBOL(param_ops_string);
 490
 491 /* sysfs output in /sys/modules/XYZ/parameters/ */
 492 #define to_module_attr(n) container_of(n, struct module_attribute, attr)
 493 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 494
 495 extern struct kernel_param __start___param[], __stop___param[];
 496
 497 struct param_attribute
 498 {
 499         struct module_attribute mattr;
 500         const struct kernel_param *param;
 501 };
 502
 503 struct module_param_attrs
 504 {
 505         unsigned int num;
 506         struct attribute_group grp;
 507         struct param_attribute attrs[0];
 508 };
 509
 510 #ifdef CONFIG_SYSFS
 511 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 512
 513 static ssize_t param_attr_show(struct module_attribute *mattr,
 514                                struct module_kobject *mk, char *buf)
 515 {
 516         int count;
 517         struct param_attribute *attribute = to_param_attr(mattr);
 518
 519         if (!attribute->param->ops->get)
 520                 return -EPERM;
 521
 522         mutex_lock(&param_lock);
 523         count = attribute->param->ops->get(buf, attribute->param);
 524         mutex_unlock(&param_lock);
 525         if (count > 0) {
 526                 strcat(buf, "\n");
 527                 ++count;
 528         }
 529         return count;
 530 }
 531
 532 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 533 static ssize_t param_attr_store(struct module_attribute *mattr,
 534                                 struct module_kobject *km,
 535                                 const char *buf, size_t len)
 536 {
 537         int err;
 538         struct param_attribute *attribute = to_param_attr(mattr);
 539
 540         if (!attribute->param->ops->set)
 541                 return -EPERM;
 542
 543         mutex_lock(&param_lock);
 544         err = attribute->param->ops->set(buf, attribute->param);
 545         mutex_unlock(&param_lock);
 546         if (!err)
 547                 return len;
 548         return err;
 549 }
 550 #endif
 551
 552 #ifdef CONFIG_MODULES
 553 #define __modinit
 554 #else
 555 #define __modinit __init
 556 #endif
 557
 558 #ifdef CONFIG_SYSFS
 559 void __kernel_param_lock(void)
 560 {
 561         mutex_lock(&param_lock);
 562 }
 563 EXPORT_SYMBOL(__kernel_param_lock);
 564
 565 void __kernel_param_unlock(void)
 566 {
 567         mutex_unlock(&param_lock);
 568 }
 569 EXPORT_SYMBOL(__kernel_param_unlock);
 570
 571 /*
 572  * add_sysfs_param - add a parameter to sysfs
 573  * @mk: struct module_kobject
 574  * @kparam: the actual parameter definition to add to sysfs
 575  * @name: name of parameter
 576  *
 577  * Create a kobject if for a (per-module) parameter if mp NULL, and
 578  * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 579  * if there's an error.
 580  */
 581 static __modinit int add_sysfs_param(struct module_kobject *mk,
 582                                      const struct kernel_param *kp,
 583                                      const char *name)
 584 {
 585         struct module_param_attrs *new;
 586         struct attribute **attrs;
 587         int err, num;
 588
 589         /* We don't bother calling this with invisible parameters. */
 590         BUG_ON(!kp->perm);
 591
 592         if (!mk->mp) {
 593                 num = 0;
 594                 attrs = NULL;
 595         } else {
 596                 num = mk->mp->num;
 597                 attrs = mk->mp->grp.attrs;
 598         }
 599
 600         /* Enlarge. */
 601         new = krealloc(mk->mp,
 602                        sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
 603                        GFP_KERNEL);
 604         if (!new) {
 605                 kfree(mk->mp);
 606                 err = -ENOMEM;
 607                 goto fail;
 608         }
 609         attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
 610         if (!attrs) {
 611                 err = -ENOMEM;
 612                 goto fail_free_new;
 613         }
 614
 615         /* Sysfs wants everything zeroed. */
 616         memset(new, 0, sizeof(*new));
 617         memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
 618         memset(&attrs[num], 0, sizeof(attrs[num]));
 619         new->grp.name = "parameters";
 620         new->grp.attrs = attrs;
 621
 622         /* Tack new one on the end. */
 623         sysfs_attr_init(&new->attrs[num].mattr.attr);
 624         new->attrs[num].param = kp;
 625         new->attrs[num].mattr.show = param_attr_show;
 626         new->attrs[num].mattr.store = param_attr_store;
 627         new->attrs[num].mattr.attr.name = (char *)name;
 628         new->attrs[num].mattr.attr.mode = kp->perm;
 629         new->num = num+1;
 630
 631         /* Fix up all the pointers, since krealloc can move us */
 632         for (num = 0; num < new->num; num++)
 633                 new->grp.attrs[num] = &new->attrs[num].mattr.attr;
 634         new->grp.attrs[num] = NULL;
 635
 636         mk->mp = new;
 637         return 0;
 638
 639 fail_free_new:
 640         kfree(new);
 641 fail:
 642         mk->mp = NULL;
 643         return err;
 644 }
 645
 646 #ifdef CONFIG_MODULES
 647 static void free_module_param_attrs(struct module_kobject *mk)
 648 {
 649         kfree(mk->mp->grp.attrs);
 650         kfree(mk->mp);
 651         mk->mp = NULL;
 652 }
 653
 654 /*
 655  * module_param_sysfs_setup - setup sysfs support for one module
 656  * @mod: module
 657  * @kparam: module parameters (array)
 658  * @num_params: number of module parameters
 659  *
 660  * Adds sysfs entries for module parameters under
 661  * /sys/module/[mod->name]/parameters/
 662  */
 663 int module_param_sysfs_setup(struct module *mod,
 664                              const struct kernel_param *kparam,
 665                              unsigned int num_params)
 666 {
 667         int i, err;
 668         bool params = false;
 669
 670         for (i = 0; i < num_params; i++) {
 671                 if (kparam[i].perm == 0)
 672                         continue;
 673                 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 674                 if (err)
 675                         return err;
 676                 params = true;
 677         }
 678
 679         if (!params)
 680                 return 0;
 681
 682         /* Create the param group. */
 683         err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 684         if (err)
 685                 free_module_param_attrs(&mod->mkobj);
 686         return err;
 687 }
 688
 689 /*
 690  * module_param_sysfs_remove - remove sysfs support for one module
 691  * @mod: module
 692  *
 693  * Remove sysfs entries for module parameters and the corresponding
 694  * kobject.
 695  */
 696 void module_param_sysfs_remove(struct module *mod)
 697 {
 698         if (mod->mkobj.mp) {
 699                 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 700                 /* We are positive that no one is using any param
 701                  * attrs at this point.  Deallocate immediately. */
 702                 free_module_param_attrs(&mod->mkobj);
 703         }
 704 }
 705 #endif
 706
 707 void destroy_params(const struct kernel_param *params, unsigned num)
 708 {
 709         unsigned int i;
 710
 711         for (i = 0; i < num; i++)
 712                 if (params[i].ops->free)
 713                         params[i].ops->free(params[i].arg);
 714 }
 715
 716 static struct module_kobject * __init locate_module_kobject(const char *name)
 717 {
 718         struct module_kobject *mk;
 719         struct kobject *kobj;
 720         int err;
 721
 722         kobj = kset_find_obj(module_kset, name);
 723         if (kobj) {
 724                 mk = to_module_kobject(kobj);
 725         } else {
 726                 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 727                 BUG_ON(!mk);
 728
 729                 mk->mod = THIS_MODULE;
 730                 mk->kobj.kset = module_kset;
 731                 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 732                                            "%s", name);
 733 #ifdef CONFIG_MODULES
 734                 if (!err)
 735                         err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
 736 #endif
 737                 if (err) {
 738                         kobject_put(&mk->kobj);
 739                         printk(KERN_ERR
 740                                 "Module '%s' failed add to sysfs, error number %d\n",
 741                                 name, err);
 742                         printk(KERN_ERR
 743                                 "The system will be unstable now.\n");
 744                         return NULL;
 745                 }
 746
 747                 /* So that we hold reference in both cases. */
 748                 kobject_get(&mk->kobj);
 749         }
 750
 751         return mk;
 752 }
 753
 754 static void __init kernel_add_sysfs_param(const char *name,
 755                                           struct kernel_param *kparam,
 756                                           unsigned int name_skip)
 757 {
 758         struct module_kobject *mk;
 759         int err;
 760
 761         mk = locate_module_kobject(name);
 762         if (!mk)
 763                 return;
 764
 765         /* We need to remove old parameters before adding more. */
 766         if (mk->mp)
 767                 sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 768
 769         /* These should not fail at boot. */
 770         err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 771         BUG_ON(err);
 772         err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 773         BUG_ON(err);
 774         kobject_uevent(&mk->kobj, KOBJ_ADD);
 775         kobject_put(&mk->kobj);
 776 }
 777
 778 /*
 779  * param_sysfs_builtin - add contents in /sys/parameters for built-in modules
 780  *
 781  * Add module_parameters to sysfs for "modules" built into the kernel.
 782  *
 783  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 784  * "parameter" name is stored behind a dot in kernel_param->name. So,
 785  * extract the "module" name for all built-in kernel_param-eters,
 786  * and for all who have the same, call kernel_add_sysfs_param.
 787  */
 788 static void __init param_sysfs_builtin(void)
 789 {
 790         struct kernel_param *kp;
 791         unsigned int name_len;
 792         char modname[MODULE_NAME_LEN];
 793
 794         for (kp = __start___param; kp < __stop___param; kp++) {
 795                 char *dot;
 796
 797                 if (kp->perm == 0)
 798                         continue;
 799
 800                 dot = strchr(kp->name, '.');
 801                 if (!dot) {
 802                         /* This happens for core_param() */
 803                         strcpy(modname, "kernel");
 804                         name_len = 0;
 805                 } else {
 806                         name_len = dot - kp->name + 1;
 807                         strlcpy(modname, kp->name, name_len);
 808                 }
 809                 kernel_add_sysfs_param(modname, kp, name_len);
 810         }
 811 }
 812
 813 ssize_t __modver_version_show(struct module_attribute *mattr,
 814                               struct module_kobject *mk, char *buf)
 815 {
 816         struct module_version_attribute *vattr =
 817                 container_of(mattr, struct module_version_attribute, mattr);
 818
 819         return sprintf(buf, "%s\n", vattr->version);
 820 }
 821
 822 extern const struct module_version_attribute *__start___modver[];
 823 extern const struct module_version_attribute *__stop___modver[];
 824
 825 static void __init version_sysfs_builtin(void)
 826 {
 827         const struct module_version_attribute **p;
 828         struct module_kobject *mk;
 829         int err;
 830
 831         for (p = __start___modver; p < __stop___modver; p++) {
 832                 const struct module_version_attribute *vattr = *p;
 833
 834                 mk = locate_module_kobject(vattr->module_name);
 835                 if (mk) {
 836                         err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
 837                         kobject_uevent(&mk->kobj, KOBJ_ADD);
 838                         kobject_put(&mk->kobj);
 839                 }
 840         }
 841 }
 842
 843 /* module-related sysfs stuff */
 844
 845 static ssize_t module_attr_show(struct kobject *kobj,
 846                                 struct attribute *attr,
 847                                 char *buf)
 848 {
 849         struct module_attribute *attribute;
 850         struct module_kobject *mk;
 851         int ret;
 852
 853         attribute = to_module_attr(attr);
 854         mk = to_module_kobject(kobj);
 855
 856         if (!attribute->show)
 857                 return -EIO;
 858
 859         ret = attribute->show(attribute, mk, buf);
 860
 861         return ret;
 862 }
 863
 864 static ssize_t module_attr_store(struct kobject *kobj,
 865                                 struct attribute *attr,
 866                                 const char *buf, size_t len)
 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->store)
 876                 return -EIO;
 877
 878         ret = attribute->store(attribute, mk, buf, len);
 879
 880         return ret;
 881 }
 882
 883 static const struct sysfs_ops module_sysfs_ops = {
 884         .show = module_attr_show,
 885         .store = module_attr_store,
 886 };
 887
 888 static int uevent_filter(struct kset *kset, struct kobject *kobj)
 889 {
 890         struct kobj_type *ktype = get_ktype(kobj);
 891
 892         if (ktype == &module_ktype)
 893                 return 1;
 894         return 0;
 895 }
 896
 897 static const struct kset_uevent_ops module_uevent_ops = {
 898         .filter = uevent_filter,
 899 };
 900
 901 struct kset *module_kset;
 902 int module_sysfs_initialized;
 903
 904 struct kobj_type module_ktype = {
 905         .sysfs_ops =    &module_sysfs_ops,
 906 };
 907
 908 /*
 909  * param_sysfs_init - wrapper for built-in params support
 910  */
 911 static int __init param_sysfs_init(void)
 912 {
 913         module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
 914         if (!module_kset) {
 915                 printk(KERN_WARNING "%s (%d): error creating kset\n",
 916                         __FILE__, __LINE__);
 917                 return -ENOMEM;
 918         }
 919         module_sysfs_initialized = 1;
 920
 921         version_sysfs_builtin();
 922         param_sysfs_builtin();
 923
 924         return 0;
 925 }
 926 subsys_initcall(param_sysfs_init);
 927
 928 #endif /* CONFIG_SYSFS */