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 /* This just allows us to keep track of which parameters are kmalloced. */
  35 struct kmalloced_param {
  36         struct list_head list;
  37         char val[];
  38 };
  39 static DEFINE_MUTEX(param_lock);
  40 static LIST_HEAD(kmalloced_params);
  41
  42 static void *kmalloc_parameter(unsigned int size)
  43 {
  44         struct kmalloced_param *p;
  45
  46         p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
  47         if (!p)
  48                 return NULL;
  49
  50         mutex_lock(&param_lock);
  51         list_add(&p->list, &kmalloced_params);
  52         mutex_unlock(&param_lock);
  53
  54         return p->val;
  55 }
  56
  57 /* Does nothing if parameter wasn't kmalloced above. */
  58 static void maybe_kfree_parameter(void *param)
  59 {
  60         struct kmalloced_param *p;
  61
  62         mutex_lock(&param_lock);
  63         list_for_each_entry(p, &kmalloced_params, list) {
  64                 if (p->val == param) {
  65                         list_del(&p->list);
  66                         kfree(p);
  67                         break;
  68                 }
  69         }
  70         mutex_unlock(&param_lock);
  71 }
  72
  73 static inline char dash2underscore(char c)
  74 {
  75         if (c == '-')
  76                 return '_';
  77         return c;
  78 }
  79
  80 static inline int parameq(const char *input, const char *paramname)
  81 {
  82         unsigned int i;
  83         for (i = 0; dash2underscore(input[i]) == paramname[i]; i++)
  84                 if (input[i] == '\0')
  85                         return 1;
  86         return 0;
  87 }
  88
  89 static int parse_one(char *param,
  90                      char *val,
  91                      struct kernel_param *params,
  92                      unsigned num_params,
  93                      int (*handle_unknown)(char *param, char *val))
  94 {
  95         unsigned int i;
  96
  97         /* Find parameter */
  98         for (i = 0; i < num_params; i++) {
  99                 if (parameq(param, params[i].name)) {
 100                         /* Noone handled NULL, so do it here. */
 101                         if (!val && params[i].ops->set != param_set_bool)
 102                                 return -EINVAL;
 103                         DEBUGP("They are equal!  Calling %p\n",
 104                                params[i].ops->set);
 105                         return params[i].ops->set(val, &params[i]);
 106                 }
 107         }
 108
 109         if (handle_unknown) {
 110                 DEBUGP("Unknown argument: calling %p\n", handle_unknown);
 111                 return handle_unknown(param, val);
 112         }
 113
 114         DEBUGP("Unknown argument `%s'\n", param);
 115         return -ENOENT;
 116 }
 117
 118 /* You can use " around spaces, but can't escape ". */
 119 /* Hyphens and underscores equivalent in parameter names. */
 120 static char *next_arg(char *args, char **param, char **val)
 121 {
 122         unsigned int i, equals = 0;
 123         int in_quote = 0, quoted = 0;
 124         char *next;
 125
 126         if (*args == '"') {
 127                 args++;
 128                 in_quote = 1;
 129                 quoted = 1;
 130         }
 131
 132         for (i = 0; args[i]; i++) {
 133                 if (isspace(args[i]) && !in_quote)
 134                         break;
 135                 if (equals == 0) {
 136                         if (args[i] == '=')
 137                                 equals = i;
 138                 }
 139                 if (args[i] == '"')
 140                         in_quote = !in_quote;
 141         }
 142
 143         *param = args;
 144         if (!equals)
 145                 *val = NULL;
 146         else {
 147                 args[equals] = '\0';
 148                 *val = args + equals + 1;
 149
 150                 /* Don't include quotes in value. */
 151                 if (**val == '"') {
 152                         (*val)++;
 153                         if (args[i-1] == '"')
 154                                 args[i-1] = '\0';
 155                 }
 156                 if (quoted && args[i-1] == '"')
 157                         args[i-1] = '\0';
 158         }
 159
 160         if (args[i]) {
 161                 args[i] = '\0';
 162                 next = args + i + 1;
 163         } else
 164                 next = args + i;
 165
 166         /* Chew up trailing spaces. */
 167         return skip_spaces(next);
 168 }
 169
 170 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 171 int parse_args(const char *name,
 172                char *args,
 173                struct kernel_param *params,
 174                unsigned num,
 175                int (*unknown)(char *param, char *val))
 176 {
 177         char *param, *val;
 178
 179         DEBUGP("Parsing ARGS: %s\n", args);
 180
 181         /* Chew leading spaces */
 182         args = skip_spaces(args);
 183
 184         while (*args) {
 185                 int ret;
 186                 int irq_was_disabled;
 187
 188                 args = next_arg(args, &param, &val);
 189                 irq_was_disabled = irqs_disabled();
 190                 ret = parse_one(param, val, params, num, unknown);
 191                 if (irq_was_disabled && !irqs_disabled()) {
 192                         printk(KERN_WARNING "parse_args(): option '%s' enabled "
 193                                         "irq's!\n", param);
 194                 }
 195                 switch (ret) {
 196                 case -ENOENT:
 197                         printk(KERN_ERR "%s: Unknown parameter `%s'\n",
 198                                name, param);
 199                         return ret;
 200                 case -ENOSPC:
 201                         printk(KERN_ERR
 202                                "%s: `%s' too large for parameter `%s'\n",
 203                                name, val ?: "", param);
 204                         return ret;
 205                 case 0:
 206                         break;
 207                 default:
 208                         printk(KERN_ERR
 209                                "%s: `%s' invalid for parameter `%s'\n",
 210                                name, val ?: "", param);
 211                         return ret;
 212                 }
 213         }
 214
 215         /* All parsed OK. */
 216         return 0;
 217 }
 218
 219 /* Lazy bastard, eh? */
 220 #define STANDARD_PARAM_DEF(name, type, format, tmptype, strtolfn)       \
 221         int param_set_##name(const char *val, const struct kernel_param *kp) \
 222         {                                                               \
 223                 tmptype l;                                              \
 224                 int ret;                                                \
 225                                                                         \
 226                 ret = strtolfn(val, 0, &l);                             \
 227                 if (ret == -EINVAL || ((type)l != l))                   \
 228                         return -EINVAL;                                 \
 229                 *((type *)kp->arg) = l;                                 \
 230                 return 0;                                               \
 231         }                                                               \
 232         int param_get_##name(char *buffer, const struct kernel_param *kp) \
 233         {                                                               \
 234                 return sprintf(buffer, format, *((type *)kp->arg));     \
 235         }                                                               \
 236         struct kernel_param_ops param_ops_##name = {                    \
 237                 .set = param_set_##name,                                \
 238                 .get = param_get_##name,                                \
 239         };                                                              \
 240         EXPORT_SYMBOL(param_set_##name);                                \
 241         EXPORT_SYMBOL(param_get_##name);                                \
 242         EXPORT_SYMBOL(param_ops_##name)
 243
 244
 245 STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, strict_strtoul);
 246 STANDARD_PARAM_DEF(short, short, "%hi", long, strict_strtol);
 247 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, strict_strtoul);
 248 STANDARD_PARAM_DEF(int, int, "%i", long, strict_strtol);
 249 STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, strict_strtoul);
 250 STANDARD_PARAM_DEF(long, long, "%li", long, strict_strtol);
 251 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, strict_strtoul);
 252
 253 int param_set_charp(const char *val, const struct kernel_param *kp)
 254 {
 255         if (strlen(val) > 1024) {
 256                 printk(KERN_ERR "%s: string parameter too long\n",
 257                        kp->name);
 258                 return -ENOSPC;
 259         }
 260
 261         maybe_kfree_parameter(*(char **)kp->arg);
 262
 263         /* This is a hack.  We can't kmalloc in early boot, and we
 264          * don't need to; this mangled commandline is preserved. */
 265         if (slab_is_available()) {
 266                 *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
 267                 if (!*(char **)kp->arg)
 268                         return -ENOMEM;
 269                 strcpy(*(char **)kp->arg, val);
 270         } else
 271                 *(const char **)kp->arg = val;
 272
 273         return 0;
 274 }
 275 EXPORT_SYMBOL(param_set_charp);
 276
 277 int param_get_charp(char *buffer, const struct kernel_param *kp)
 278 {
 279         return sprintf(buffer, "%s", *((char **)kp->arg));
 280 }
 281 EXPORT_SYMBOL(param_get_charp);
 282
 283 static void param_free_charp(void *arg)
 284 {
 285         maybe_kfree_parameter(*((char **)arg));
 286 }
 287
 288 struct kernel_param_ops param_ops_charp = {
 289         .set = param_set_charp,
 290         .get = param_get_charp,
 291         .free = param_free_charp,
 292 };
 293 EXPORT_SYMBOL(param_ops_charp);
 294
 295 /* Actually could be a bool or an int, for historical reasons. */
 296 int param_set_bool(const char *val, const struct kernel_param *kp)
 297 {
 298         bool v;
 299
 300         /* No equals means "set"... */
 301         if (!val) val = "1";
 302
 303         /* One of =[yYnN01] */
 304         switch (val[0]) {
 305         case 'y': case 'Y': case '1':
 306                 v = true;
 307                 break;
 308         case 'n': case 'N': case '0':
 309                 v = false;
 310                 break;
 311         default:
 312                 return -EINVAL;
 313         }
 314
 315         if (kp->flags & KPARAM_ISBOOL)
 316                 *(bool *)kp->arg = v;
 317         else
 318                 *(int *)kp->arg = v;
 319         return 0;
 320 }
 321 EXPORT_SYMBOL(param_set_bool);
 322
 323 int param_get_bool(char *buffer, const struct kernel_param *kp)
 324 {
 325         bool val;
 326         if (kp->flags & KPARAM_ISBOOL)
 327                 val = *(bool *)kp->arg;
 328         else
 329                 val = *(int *)kp->arg;
 330
 331         /* Y and N chosen as being relatively non-coder friendly */
 332         return sprintf(buffer, "%c", val ? 'Y' : 'N');
 333 }
 334 EXPORT_SYMBOL(param_get_bool);
 335
 336 struct kernel_param_ops param_ops_bool = {
 337         .set = param_set_bool,
 338         .get = param_get_bool,
 339 };
 340 EXPORT_SYMBOL(param_ops_bool);
 341
 342 /* This one must be bool. */
 343 int param_set_invbool(const char *val, const struct kernel_param *kp)
 344 {
 345         int ret;
 346         bool boolval;
 347         struct kernel_param dummy;
 348
 349         dummy.arg = &boolval;
 350         dummy.flags = KPARAM_ISBOOL;
 351         ret = param_set_bool(val, &dummy);
 352         if (ret == 0)
 353                 *(bool *)kp->arg = !boolval;
 354         return ret;
 355 }
 356 EXPORT_SYMBOL(param_set_invbool);
 357
 358 int param_get_invbool(char *buffer, const struct kernel_param *kp)
 359 {
 360         return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
 361 }
 362 EXPORT_SYMBOL(param_get_invbool);
 363
 364 struct kernel_param_ops param_ops_invbool = {
 365         .set = param_set_invbool,
 366         .get = param_get_invbool,
 367 };
 368 EXPORT_SYMBOL(param_ops_invbool);
 369
 370 /* We break the rule and mangle the string. */
 371 static int param_array(const char *name,
 372                        const char *val,
 373                        unsigned int min, unsigned int max,
 374                        void *elem, int elemsize,
 375                        int (*set)(const char *, const struct kernel_param *kp),
 376                        u16 flags,
 377                        unsigned int *num)
 378 {
 379         int ret;
 380         struct kernel_param kp;
 381         char save;
 382
 383         /* Get the name right for errors. */
 384         kp.name = name;
 385         kp.arg = elem;
 386         kp.flags = flags;
 387
 388         *num = 0;
 389         /* We expect a comma-separated list of values. */
 390         do {
 391                 int len;
 392
 393                 if (*num == max) {
 394                         printk(KERN_ERR "%s: can only take %i arguments\n",
 395                                name, max);
 396                         return -EINVAL;
 397                 }
 398                 len = strcspn(val, ",");
 399
 400                 /* nul-terminate and parse */
 401                 save = val[len];
 402                 ((char *)val)[len] = '\0';
 403                 ret = set(val, &kp);
 404
 405                 if (ret != 0)
 406                         return ret;
 407                 kp.arg += elemsize;
 408                 val += len+1;
 409                 (*num)++;
 410         } while (save == ',');
 411
 412         if (*num < min) {
 413                 printk(KERN_ERR "%s: needs at least %i arguments\n",
 414                        name, min);
 415                 return -EINVAL;
 416         }
 417         return 0;
 418 }
 419
 420 static int param_array_set(const char *val, const struct kernel_param *kp)
 421 {
 422         const struct kparam_array *arr = kp->arr;
 423         unsigned int temp_num;
 424
 425         return param_array(kp->name, val, 1, arr->max, arr->elem,
 426                            arr->elemsize, arr->ops->set, kp->flags,
 427                            arr->num ?: &temp_num);
 428 }
 429
 430 static int param_array_get(char *buffer, const struct kernel_param *kp)
 431 {
 432         int i, off, ret;
 433         const struct kparam_array *arr = kp->arr;
 434         struct kernel_param p;
 435
 436         p = *kp;
 437         for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 438                 if (i)
 439                         buffer[off++] = ',';
 440                 p.arg = arr->elem + arr->elemsize * i;
 441                 ret = arr->ops->get(buffer + off, &p);
 442                 if (ret < 0)
 443                         return ret;
 444                 off += ret;
 445         }
 446         buffer[off] = '\0';
 447         return off;
 448 }
 449
 450 static void param_array_free(void *arg)
 451 {
 452         unsigned int i;
 453         const struct kparam_array *arr = arg;
 454
 455         if (arr->ops->free)
 456                 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 457                         arr->ops->free(arr->elem + arr->elemsize * i);
 458 }
 459
 460 struct kernel_param_ops param_array_ops = {
 461         .set = param_array_set,
 462         .get = param_array_get,
 463         .free = param_array_free,
 464 };
 465 EXPORT_SYMBOL(param_array_ops);
 466
 467 int param_set_copystring(const char *val, const struct kernel_param *kp)
 468 {
 469         const struct kparam_string *kps = kp->str;
 470
 471         if (strlen(val)+1 > kps->maxlen) {
 472                 printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
 473                        kp->name, kps->maxlen-1);
 474                 return -ENOSPC;
 475         }
 476         strcpy(kps->string, val);
 477         return 0;
 478 }
 479 EXPORT_SYMBOL(param_set_copystring);
 480
 481 int param_get_string(char *buffer, const struct kernel_param *kp)
 482 {
 483         const struct kparam_string *kps = kp->str;
 484         return strlcpy(buffer, kps->string, kps->maxlen);
 485 }
 486 EXPORT_SYMBOL(param_get_string);
 487
 488 struct kernel_param_ops param_ops_string = {
 489         .set = param_set_copystring,
 490         .get = param_get_string,
 491 };
 492 EXPORT_SYMBOL(param_ops_string);
 493
 494 /* sysfs output in /sys/modules/XYZ/parameters/ */
 495 #define to_module_attr(n) container_of(n, struct module_attribute, attr)
 496 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 497
 498 extern struct kernel_param __start___param[], __stop___param[];
 499
 500 struct param_attribute
 501 {
 502         struct module_attribute mattr;
 503         const struct kernel_param *param;
 504 };
 505
 506 struct module_param_attrs
 507 {
 508         unsigned int num;
 509         struct attribute_group grp;
 510         struct param_attribute attrs[0];
 511 };
 512
 513 #ifdef CONFIG_SYSFS
 514 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 515
 516 static ssize_t param_attr_show(struct module_attribute *mattr,
 517                                struct module *mod, char *buf)
 518 {
 519         int count;
 520         struct param_attribute *attribute = to_param_attr(mattr);
 521
 522         if (!attribute->param->ops->get)
 523                 return -EPERM;
 524
 525         count = attribute->param->ops->get(buf, attribute->param);
 526         if (count > 0) {
 527                 strcat(buf, "\n");
 528                 ++count;
 529         }
 530         return count;
 531 }
 532
 533 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 534 static ssize_t param_attr_store(struct module_attribute *mattr,
 535                                 struct module *owner,
 536                                 const char *buf, size_t len)
 537 {
 538         int err;
 539         struct param_attribute *attribute = to_param_attr(mattr);
 540
 541         if (!attribute->param->ops->set)
 542                 return -EPERM;
 543
 544         err = attribute->param->ops->set(buf, attribute->param);
 545         if (!err)
 546                 return len;
 547         return err;
 548 }
 549 #endif
 550
 551 #ifdef CONFIG_MODULES
 552 #define __modinit
 553 #else
 554 #define __modinit __init
 555 #endif
 556
 557 #ifdef CONFIG_SYSFS
 558 /*
 559  * add_sysfs_param - add a parameter to sysfs
 560  * @mk: struct module_kobject
 561  * @kparam: the actual parameter definition to add to sysfs
 562  * @name: name of parameter
 563  *
 564  * Create a kobject if for a (per-module) parameter if mp NULL, and
 565  * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 566  * if there's an error.
 567  */
 568 static __modinit int add_sysfs_param(struct module_kobject *mk,
 569                                      const struct kernel_param *kp,
 570                                      const char *name)
 571 {
 572         struct module_param_attrs *new;
 573         struct attribute **attrs;
 574         int err, num;
 575
 576         /* We don't bother calling this with invisible parameters. */
 577         BUG_ON(!kp->perm);
 578
 579         if (!mk->mp) {
 580                 num = 0;
 581                 attrs = NULL;
 582         } else {
 583                 num = mk->mp->num;
 584                 attrs = mk->mp->grp.attrs;
 585         }
 586
 587         /* Enlarge. */
 588         new = krealloc(mk->mp,
 589                        sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
 590                        GFP_KERNEL);
 591         if (!new) {
 592                 kfree(mk->mp);
 593                 err = -ENOMEM;
 594                 goto fail;
 595         }
 596         attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
 597         if (!attrs) {
 598                 err = -ENOMEM;
 599                 goto fail_free_new;
 600         }
 601
 602         /* Sysfs wants everything zeroed. */
 603         memset(new, 0, sizeof(*new));
 604         memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
 605         memset(&attrs[num], 0, sizeof(attrs[num]));
 606         new->grp.name = "parameters";
 607         new->grp.attrs = attrs;
 608
 609         /* Tack new one on the end. */
 610         sysfs_attr_init(&new->attrs[num].mattr.attr);
 611         new->attrs[num].param = kp;
 612         new->attrs[num].mattr.show = param_attr_show;
 613         new->attrs[num].mattr.store = param_attr_store;
 614         new->attrs[num].mattr.attr.name = (char *)name;
 615         new->attrs[num].mattr.attr.mode = kp->perm;
 616         new->num = num+1;
 617
 618         /* Fix up all the pointers, since krealloc can move us */
 619         for (num = 0; num < new->num; num++)
 620                 new->grp.attrs[num] = &new->attrs[num].mattr.attr;
 621         new->grp.attrs[num] = NULL;
 622
 623         mk->mp = new;
 624         return 0;
 625
 626 fail_free_new:
 627         kfree(new);
 628 fail:
 629         mk->mp = NULL;
 630         return err;
 631 }
 632
 633 #ifdef CONFIG_MODULES
 634 static void free_module_param_attrs(struct module_kobject *mk)
 635 {
 636         kfree(mk->mp->grp.attrs);
 637         kfree(mk->mp);
 638         mk->mp = NULL;
 639 }
 640
 641 /*
 642  * module_param_sysfs_setup - setup sysfs support for one module
 643  * @mod: module
 644  * @kparam: module parameters (array)
 645  * @num_params: number of module parameters
 646  *
 647  * Adds sysfs entries for module parameters under
 648  * /sys/module/[mod->name]/parameters/
 649  */
 650 int module_param_sysfs_setup(struct module *mod,
 651                              const struct kernel_param *kparam,
 652                              unsigned int num_params)
 653 {
 654         int i, err;
 655         bool params = false;
 656
 657         for (i = 0; i < num_params; i++) {
 658                 if (kparam[i].perm == 0)
 659                         continue;
 660                 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 661                 if (err)
 662                         return err;
 663                 params = true;
 664         }
 665
 666         if (!params)
 667                 return 0;
 668
 669         /* Create the param group. */
 670         err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 671         if (err)
 672                 free_module_param_attrs(&mod->mkobj);
 673         return err;
 674 }
 675
 676 /*
 677  * module_param_sysfs_remove - remove sysfs support for one module
 678  * @mod: module
 679  *
 680  * Remove sysfs entries for module parameters and the corresponding
 681  * kobject.
 682  */
 683 void module_param_sysfs_remove(struct module *mod)
 684 {
 685         if (mod->mkobj.mp) {
 686                 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 687                 /* We are positive that no one is using any param
 688                  * attrs at this point.  Deallocate immediately. */
 689                 free_module_param_attrs(&mod->mkobj);
 690         }
 691 }
 692 #endif
 693
 694 void destroy_params(const struct kernel_param *params, unsigned num)
 695 {
 696         unsigned int i;
 697
 698         for (i = 0; i < num; i++)
 699                 if (params[i].ops->free)
 700                         params[i].ops->free(params[i].arg);
 701 }
 702
 703 static void __init kernel_add_sysfs_param(const char *name,
 704                                           struct kernel_param *kparam,
 705                                           unsigned int name_skip)
 706 {
 707         struct module_kobject *mk;
 708         struct kobject *kobj;
 709         int err;
 710
 711         kobj = kset_find_obj(module_kset, name);
 712         if (kobj) {
 713                 /* We already have one.  Remove params so we can add more. */
 714                 mk = to_module_kobject(kobj);
 715                 /* We need to remove it before adding parameters. */
 716                 sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 717         } else {
 718                 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 719                 BUG_ON(!mk);
 720
 721                 mk->mod = THIS_MODULE;
 722                 mk->kobj.kset = module_kset;
 723                 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 724                                            "%s", name);
 725                 if (err) {
 726                         kobject_put(&mk->kobj);
 727                         printk(KERN_ERR "Module '%s' failed add to sysfs, "
 728                                "error number %d\n", name, err);
 729                         printk(KERN_ERR "The system will be unstable now.\n");
 730                         return;
 731                 }
 732                 /* So that exit path is even. */
 733                 kobject_get(&mk->kobj);
 734         }
 735
 736         /* These should not fail at boot. */
 737         err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 738         BUG_ON(err);
 739         err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 740         BUG_ON(err);
 741         kobject_uevent(&mk->kobj, KOBJ_ADD);
 742         kobject_put(&mk->kobj);
 743 }
 744
 745 /*
 746  * param_sysfs_builtin - add contents in /sys/parameters for built-in modules
 747  *
 748  * Add module_parameters to sysfs for "modules" built into the kernel.
 749  *
 750  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 751  * "parameter" name is stored behind a dot in kernel_param->name. So,
 752  * extract the "module" name for all built-in kernel_param-eters,
 753  * and for all who have the same, call kernel_add_sysfs_param.
 754  */
 755 static void __init param_sysfs_builtin(void)
 756 {
 757         struct kernel_param *kp;
 758         unsigned int name_len;
 759         char modname[MODULE_NAME_LEN];
 760
 761         for (kp = __start___param; kp < __stop___param; kp++) {
 762                 char *dot;
 763
 764                 if (kp->perm == 0)
 765                         continue;
 766
 767                 dot = strchr(kp->name, '.');
 768                 if (!dot) {
 769                         /* This happens for core_param() */
 770                         strcpy(modname, "kernel");
 771                         name_len = 0;
 772                 } else {
 773                         name_len = dot - kp->name + 1;
 774                         strlcpy(modname, kp->name, name_len);
 775                 }
 776                 kernel_add_sysfs_param(modname, kp, name_len);
 777         }
 778 }
 779
 780
 781 /* module-related sysfs stuff */
 782
 783 static ssize_t module_attr_show(struct kobject *kobj,
 784                                 struct attribute *attr,
 785                                 char *buf)
 786 {
 787         struct module_attribute *attribute;
 788         struct module_kobject *mk;
 789         int ret;
 790
 791         attribute = to_module_attr(attr);
 792         mk = to_module_kobject(kobj);
 793
 794         if (!attribute->show)
 795                 return -EIO;
 796
 797         ret = attribute->show(attribute, mk->mod, buf);
 798
 799         return ret;
 800 }
 801
 802 static ssize_t module_attr_store(struct kobject *kobj,
 803                                 struct attribute *attr,
 804                                 const char *buf, size_t len)
 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->store)
 814                 return -EIO;
 815
 816         ret = attribute->store(attribute, mk->mod, buf, len);
 817
 818         return ret;
 819 }
 820
 821 static const struct sysfs_ops module_sysfs_ops = {
 822         .show = module_attr_show,
 823         .store = module_attr_store,
 824 };
 825
 826 static int uevent_filter(struct kset *kset, struct kobject *kobj)
 827 {
 828         struct kobj_type *ktype = get_ktype(kobj);
 829
 830         if (ktype == &module_ktype)
 831                 return 1;
 832         return 0;
 833 }
 834
 835 static const struct kset_uevent_ops module_uevent_ops = {
 836         .filter = uevent_filter,
 837 };
 838
 839 struct kset *module_kset;
 840 int module_sysfs_initialized;
 841
 842 struct kobj_type module_ktype = {
 843         .sysfs_ops =    &module_sysfs_ops,
 844 };
 845
 846 /*
 847  * param_sysfs_init - wrapper for built-in params support
 848  */
 849 static int __init param_sysfs_init(void)
 850 {
 851         module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
 852         if (!module_kset) {
 853                 printk(KERN_WARNING "%s (%d): error creating kset\n",
 854                         __FILE__, __LINE__);
 855                 return -ENOMEM;
 856         }
 857         module_sysfs_initialized = 1;
 858
 859         param_sysfs_builtin();
 860
 861         return 0;
 862 }
 863 subsys_initcall(param_sysfs_init);
 864
 865 #endif /* CONFIG_SYSFS */