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/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. */
  31 struct kmalloced_param {
  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 }
 284 EXPORT_SYMBOL(param_set_charp);
 285
 286 int param_get_charp(char *buffer, const struct kernel_param *kp)
 287 {
 288         return sprintf(buffer, "%s", *((char **)kp->arg));
 289 }
 290 EXPORT_SYMBOL(param_get_charp);
 291
 292 static void param_free_charp(void *arg)
 293 {
 294         maybe_kfree_parameter(*((char **)arg));
 295 }
 296
 297 struct kernel_param_ops param_ops_charp = {
 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 }
 313 EXPORT_SYMBOL(param_set_bool);
 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 }
 320 EXPORT_SYMBOL(param_get_bool);
 321
 322 struct kernel_param_ops param_ops_bool = {
 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 }
 341 EXPORT_SYMBOL(param_set_invbool);
 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 }
 347 EXPORT_SYMBOL(param_get_invbool);
 348
 349 struct kernel_param_ops param_ops_invbool = {
 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 }
 370 EXPORT_SYMBOL(param_set_bint);
 371
 372 struct kernel_param_ops param_ops_bint = {
 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
 468 struct kernel_param_ops param_array_ops = {
 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 }
 487 EXPORT_SYMBOL(param_set_copystring);
 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 }
 494 EXPORT_SYMBOL(param_get_string);
 495
 496 struct kernel_param_ops param_ops_string = {
 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
 508 struct param_attribute
 509 {
 510         struct module_attribute mattr;
 511         const struct kernel_param *param;
 512 };
 513
 514 struct module_param_attrs
 515 {
 516         unsigned int num;
 517         struct attribute_group grp;
 518         struct param_attribute attrs[0];
 519 };
 520
 521 #ifdef CONFIG_SYSFS
 522 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 523
 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);
 782         kobject_uevent(&mk->kobj, KOBJ_ADD);
 783         kobject_put(&mk->kobj);
 784 }
 785
 786 /*
 787  * param_sysfs_builtin - add contents in /sys/parameters for built-in modules
 788  *
 789  * Add module_parameters to sysfs for "modules" built into the kernel.
 790  *
 791  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 792  * "parameter" name is stored behind a dot in kernel_param->name. So,
 793  * extract the "module" name for all built-in kernel_param-eters,
 794  * and for all who have the same, call kernel_add_sysfs_param.
 795  */
 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
 821 ssize_t __modver_version_show(struct module_attribute *mattr,
 822                               struct module_kobject *mk, char *buf)
 823 {
 824         struct module_version_attribute *vattr =
 825                 container_of(mattr, struct module_version_attribute, mattr);
 826
 827         return sprintf(buf, "%s\n", vattr->version);
 828 }
 829
 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);
 845                         kobject_uevent(&mk->kobj, KOBJ_ADD);
 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 */