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/moduleparam.h>
  23 #include <linux/device.h>
  24 #include <linux/err.h>
  25 #include <linux/slab.h>
  26 #include <linux/ctype.h>
  27
  28 /* Protects all parameters, and incidentally kmalloced_param list. */
  29 static DEFINE_MUTEX(param_lock);
  30
  31 /* This just allows us to keep track of which parameters are kmalloced. */
  32 struct kmalloced_param {
  33         struct list_head list;
  34         char val[];
  35 };
  36 static LIST_HEAD(kmalloced_params);
  37
  38 static void *kmalloc_parameter(unsigned int size)
  39 {
  40         struct kmalloced_param *p;
  41
  42         p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
  43         if (!p)
  44                 return NULL;
  45
  46         list_add(&p->list, &kmalloced_params);
  47         return p->val;
  48 }
  49
  50 /* Does nothing if parameter wasn't kmalloced above. */
  51 static void maybe_kfree_parameter(void *param)
  52 {
  53         struct kmalloced_param *p;
  54
  55         list_for_each_entry(p, &kmalloced_params, list) {
  56                 if (p->val == param) {
  57                         list_del(&p->list);
  58                         kfree(p);
  59                         break;
  60                 }
  61         }
  62 }
  63
  64 static char dash2underscore(char c)
  65 {
  66         if (c == '-')
  67                 return '_';
  68         return c;
  69 }
  70
  71 bool parameqn(const char *a, const char *b, size_t n)
  72 {
  73         size_t i;
  74
  75         for (i = 0; i < n; i++) {
  76                 if (dash2underscore(a[i]) != dash2underscore(b[i]))
  77                         return false;
  78         }
  79         return true;
  80 }
  81
  82 bool parameq(const char *a, const char *b)
  83 {
  84         return parameqn(a, b, strlen(a)+1);
  85 }
  86
  87 static void param_check_unsafe(const struct kernel_param *kp)
  88 {
  89         if (kp->flags & KERNEL_PARAM_FL_UNSAFE) {
  90                 pr_warn("Setting dangerous option %s - tainting kernel\n",
  91                         kp->name);
  92                 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
  93         }
  94 }
  95
  96 static int parse_one(char *param,
  97                      char *val,
  98                      const char *doing,
  99                      const struct kernel_param *params,
 100                      unsigned num_params,
 101                      s16 min_level,
 102                      s16 max_level,
 103                      int (*handle_unknown)(char *param, char *val,
 104                                      const char *doing))
 105 {
 106         unsigned int i;
 107         int err;
 108
 109         /* Find parameter */
 110         for (i = 0; i < num_params; i++) {
 111                 if (parameq(param, params[i].name)) {
 112                         if (params[i].level < min_level
 113                             || params[i].level > max_level)
 114                                 return 0;
 115                         /* No one handled NULL, so do it here. */
 116                         if (!val &&
 117                             !(params[i].ops->flags & KERNEL_PARAM_OPS_FL_NOARG))
 118                                 return -EINVAL;
 119                         pr_debug("handling %s with %p\n", param,
 120                                 params[i].ops->set);
 121                         mutex_lock(&param_lock);
 122                         param_check_unsafe(&params[i]);
 123                         err = params[i].ops->set(val, &params[i]);
 124                         mutex_unlock(&param_lock);
 125                         return err;
 126                 }
 127         }
 128
 129         if (handle_unknown) {
 130                 pr_debug("doing %s: %s='%s'\n", doing, param, val);
 131                 return handle_unknown(param, val, doing);
 132         }
 133
 134         pr_debug("Unknown argument '%s'\n", param);
 135         return -ENOENT;
 136 }
 137
 138 /* You can use " around spaces, but can't escape ". */
 139 /* Hyphens and underscores equivalent in parameter names. */
 140 static char *next_arg(char *args, char **param, char **val)
 141 {
 142         unsigned int i, equals = 0;
 143         int in_quote = 0, quoted = 0;
 144         char *next;
 145
 146         if (*args == '"') {
 147                 args++;
 148                 in_quote = 1;
 149                 quoted = 1;
 150         }
 151
 152         for (i = 0; args[i]; i++) {
 153                 if (isspace(args[i]) && !in_quote)
 154                         break;
 155                 if (equals == 0) {
 156                         if (args[i] == '=')
 157                                 equals = i;
 158                 }
 159                 if (args[i] == '"')
 160                         in_quote = !in_quote;
 161         }
 162
 163         *param = args;
 164         if (!equals)
 165                 *val = NULL;
 166         else {
 167                 args[equals] = '\0';
 168                 *val = args + equals + 1;
 169
 170                 /* Don't include quotes in value. */
 171                 if (**val == '"') {
 172                         (*val)++;
 173                         if (args[i-1] == '"')
 174                                 args[i-1] = '\0';
 175                 }
 176         }
 177         if (quoted && args[i-1] == '"')
 178                 args[i-1] = '\0';
 179
 180         if (args[i]) {
 181                 args[i] = '\0';
 182                 next = args + i + 1;
 183         } else
 184                 next = args + i;
 185
 186         /* Chew up trailing spaces. */
 187         return skip_spaces(next);
 188 }
 189
 190 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 191 char *parse_args(const char *doing,
 192                  char *args,
 193                  const struct kernel_param *params,
 194                  unsigned num,
 195                  s16 min_level,
 196                  s16 max_level,
 197                  int (*unknown)(char *param, char *val, const char *doing))
 198 {
 199         char *param, *val;
 200
 201         /* Chew leading spaces */
 202         args = skip_spaces(args);
 203
 204         if (*args)
 205                 pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
 206
 207         while (*args) {
 208                 int ret;
 209                 int irq_was_disabled;
 210
 211                 args = next_arg(args, &param, &val);
 212                 /* Stop at -- */
 213                 if (!val && strcmp(param, "--") == 0)
 214                         return args;
 215                 irq_was_disabled = irqs_disabled();
 216                 ret = parse_one(param, val, doing, params, num,
 217                                 min_level, max_level, unknown);
 218                 if (irq_was_disabled && !irqs_disabled())
 219                         pr_warn("%s: option '%s' enabled irq's!\n",
 220                                 doing, param);
 221
 222                 switch (ret) {
 223                 case -ENOENT:
 224                         pr_err("%s: Unknown parameter `%s'\n", doing, param);
 225                         return ERR_PTR(ret);
 226                 case -ENOSPC:
 227                         pr_err("%s: `%s' too large for parameter `%s'\n",
 228                                doing, val ?: "", param);
 229                         return ERR_PTR(ret);
 230                 case 0:
 231                         break;
 232                 default:
 233                         pr_err("%s: `%s' invalid for parameter `%s'\n",
 234                                doing, val ?: "", param);
 235                         return ERR_PTR(ret);
 236                 }
 237         }
 238
 239         /* All parsed OK. */
 240         return NULL;
 241 }
 242
 243 /* Lazy bastard, eh? */
 244 #define STANDARD_PARAM_DEF(name, type, format, strtolfn)                \
 245         int param_set_##name(const char *val, const struct kernel_param *kp) \
 246         {                                                               \
 247                 return strtolfn(val, 0, (type *)kp->arg);               \
 248         }                                                               \
 249         int param_get_##name(char *buffer, const struct kernel_param *kp) \
 250         {                                                               \
 251                 return scnprintf(buffer, PAGE_SIZE, format,             \
 252                                 *((type *)kp->arg));                    \
 253         }                                                               \
 254         struct kernel_param_ops param_ops_##name = {                    \
 255                 .set = param_set_##name,                                \
 256                 .get = param_get_##name,                                \
 257         };                                                              \
 258         EXPORT_SYMBOL(param_set_##name);                                \
 259         EXPORT_SYMBOL(param_get_##name);                                \
 260         EXPORT_SYMBOL(param_ops_##name)
 261
 262
 263 STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", kstrtou8);
 264 STANDARD_PARAM_DEF(short, short, "%hi", kstrtos16);
 265 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", kstrtou16);
 266 STANDARD_PARAM_DEF(int, int, "%i", kstrtoint);
 267 STANDARD_PARAM_DEF(uint, unsigned int, "%u", kstrtouint);
 268 STANDARD_PARAM_DEF(long, long, "%li", kstrtol);
 269 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", kstrtoul);
 270 STANDARD_PARAM_DEF(ullong, unsigned long long, "%llu", kstrtoull);
 271
 272 int param_set_charp(const char *val, const struct kernel_param *kp)
 273 {
 274         if (strlen(val) > 1024) {
 275                 pr_err("%s: string parameter too long\n", kp->name);
 276                 return -ENOSPC;
 277         }
 278
 279         maybe_kfree_parameter(*(char **)kp->arg);
 280
 281         /* This is a hack.  We can't kmalloc in early boot, and we
 282          * don't need to; this mangled commandline is preserved. */
 283         if (slab_is_available()) {
 284                 *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
 285                 if (!*(char **)kp->arg)
 286                         return -ENOMEM;
 287                 strcpy(*(char **)kp->arg, val);
 288         } else
 289                 *(const char **)kp->arg = val;
 290
 291         return 0;
 292 }
 293 EXPORT_SYMBOL(param_set_charp);
 294
 295 int param_get_charp(char *buffer, const struct kernel_param *kp)
 296 {
 297         return scnprintf(buffer, PAGE_SIZE, "%s", *((char **)kp->arg));
 298 }
 299 EXPORT_SYMBOL(param_get_charp);
 300
 301 static void param_free_charp(void *arg)
 302 {
 303         maybe_kfree_parameter(*((char **)arg));
 304 }
 305
 306 struct kernel_param_ops param_ops_charp = {
 307         .set = param_set_charp,
 308         .get = param_get_charp,
 309         .free = param_free_charp,
 310 };
 311 EXPORT_SYMBOL(param_ops_charp);
 312
 313 /* Actually could be a bool or an int, for historical reasons. */
 314 int param_set_bool(const char *val, const struct kernel_param *kp)
 315 {
 316         /* No equals means "set"... */
 317         if (!val) val = "1";
 318
 319         /* One of =[yYnN01] */
 320         return strtobool(val, kp->arg);
 321 }
 322 EXPORT_SYMBOL(param_set_bool);
 323
 324 int param_get_bool(char *buffer, const struct kernel_param *kp)
 325 {
 326         /* Y and N chosen as being relatively non-coder friendly */
 327         return sprintf(buffer, "%c", *(bool *)kp->arg ? 'Y' : 'N');
 328 }
 329 EXPORT_SYMBOL(param_get_bool);
 330
 331 struct kernel_param_ops param_ops_bool = {
 332         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 333         .set = param_set_bool,
 334         .get = param_get_bool,
 335 };
 336 EXPORT_SYMBOL(param_ops_bool);
 337
 338 /* This one must be bool. */
 339 int param_set_invbool(const char *val, const struct kernel_param *kp)
 340 {
 341         int ret;
 342         bool boolval;
 343         struct kernel_param dummy;
 344
 345         dummy.arg = &boolval;
 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 int param_set_bint(const char *val, const struct kernel_param *kp)
 366 {
 367         struct kernel_param boolkp;
 368         bool v;
 369         int ret;
 370
 371         /* Match bool exactly, by re-using it. */
 372         boolkp = *kp;
 373         boolkp.arg = &v;
 374
 375         ret = param_set_bool(val, &boolkp);
 376         if (ret == 0)
 377                 *(int *)kp->arg = v;
 378         return ret;
 379 }
 380 EXPORT_SYMBOL(param_set_bint);
 381
 382 struct kernel_param_ops param_ops_bint = {
 383         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 384         .set = param_set_bint,
 385         .get = param_get_int,
 386 };
 387 EXPORT_SYMBOL(param_ops_bint);
 388
 389 /* We break the rule and mangle the string. */
 390 static int param_array(const char *name,
 391                        const char *val,
 392                        unsigned int min, unsigned int max,
 393                        void *elem, int elemsize,
 394                        int (*set)(const char *, const struct kernel_param *kp),
 395                        s16 level,
 396                        unsigned int *num)
 397 {
 398         int ret;
 399         struct kernel_param kp;
 400         char save;
 401
 402         /* Get the name right for errors. */
 403         kp.name = name;
 404         kp.arg = elem;
 405         kp.level = level;
 406
 407         *num = 0;
 408         /* We expect a comma-separated list of values. */
 409         do {
 410                 int len;
 411
 412                 if (*num == max) {
 413                         pr_err("%s: can only take %i arguments\n", name, max);
 414                         return -EINVAL;
 415                 }
 416                 len = strcspn(val, ",");
 417
 418                 /* nul-terminate and parse */
 419                 save = val[len];
 420                 ((char *)val)[len] = '\0';
 421                 BUG_ON(!mutex_is_locked(&param_lock));
 422                 ret = set(val, &kp);
 423
 424                 if (ret != 0)
 425                         return ret;
 426                 kp.arg += elemsize;
 427                 val += len+1;
 428                 (*num)++;
 429         } while (save == ',');
 430
 431         if (*num < min) {
 432                 pr_err("%s: needs at least %i arguments\n", name, min);
 433                 return -EINVAL;
 434         }
 435         return 0;
 436 }
 437
 438 static int param_array_set(const char *val, const struct kernel_param *kp)
 439 {
 440         const struct kparam_array *arr = kp->arr;
 441         unsigned int temp_num;
 442
 443         return param_array(kp->name, val, 1, arr->max, arr->elem,
 444                            arr->elemsize, arr->ops->set, kp->level,
 445                            arr->num ?: &temp_num);
 446 }
 447
 448 static int param_array_get(char *buffer, const struct kernel_param *kp)
 449 {
 450         int i, off, ret;
 451         const struct kparam_array *arr = kp->arr;
 452         struct kernel_param p;
 453
 454         p = *kp;
 455         for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 456                 if (i)
 457                         buffer[off++] = ',';
 458                 p.arg = arr->elem + arr->elemsize * i;
 459                 BUG_ON(!mutex_is_locked(&param_lock));
 460                 ret = arr->ops->get(buffer + off, &p);
 461                 if (ret < 0)
 462                         return ret;
 463                 off += ret;
 464         }
 465         buffer[off] = '\0';
 466         return off;
 467 }
 468
 469 static void param_array_free(void *arg)
 470 {
 471         unsigned int i;
 472         const struct kparam_array *arr = arg;
 473
 474         if (arr->ops->free)
 475                 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 476                         arr->ops->free(arr->elem + arr->elemsize * i);
 477 }
 478
 479 struct kernel_param_ops param_array_ops = {
 480         .set = param_array_set,
 481         .get = param_array_get,
 482         .free = param_array_free,
 483 };
 484 EXPORT_SYMBOL(param_array_ops);
 485
 486 int param_set_copystring(const char *val, const struct kernel_param *kp)
 487 {
 488         const struct kparam_string *kps = kp->str;
 489
 490         if (strlen(val)+1 > kps->maxlen) {
 491                 pr_err("%s: string doesn't fit in %u chars.\n",
 492                        kp->name, kps->maxlen-1);
 493                 return -ENOSPC;
 494         }
 495         strcpy(kps->string, val);
 496         return 0;
 497 }
 498 EXPORT_SYMBOL(param_set_copystring);
 499
 500 int param_get_string(char *buffer, const struct kernel_param *kp)
 501 {
 502         const struct kparam_string *kps = kp->str;
 503         return strlcpy(buffer, kps->string, kps->maxlen);
 504 }
 505 EXPORT_SYMBOL(param_get_string);
 506
 507 struct kernel_param_ops param_ops_string = {
 508         .set = param_set_copystring,
 509         .get = param_get_string,
 510 };
 511 EXPORT_SYMBOL(param_ops_string);
 512
 513 /* sysfs output in /sys/modules/XYZ/parameters/ */
 514 #define to_module_attr(n) container_of(n, struct module_attribute, attr)
 515 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 516
 517 struct param_attribute
 518 {
 519         struct module_attribute mattr;
 520         const struct kernel_param *param;
 521 };
 522
 523 struct module_param_attrs
 524 {
 525         unsigned int num;
 526         struct attribute_group grp;
 527         struct param_attribute attrs[0];
 528 };
 529
 530 #ifdef CONFIG_SYSFS
 531 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 532
 533 static ssize_t param_attr_show(struct module_attribute *mattr,
 534                                struct module_kobject *mk, char *buf)
 535 {
 536         int count;
 537         struct param_attribute *attribute = to_param_attr(mattr);
 538
 539         if (!attribute->param->ops->get)
 540                 return -EPERM;
 541
 542         mutex_lock(&param_lock);
 543         count = attribute->param->ops->get(buf, attribute->param);
 544         mutex_unlock(&param_lock);
 545         if (count > 0) {
 546                 strcat(buf, "\n");
 547                 ++count;
 548         }
 549         return count;
 550 }
 551
 552 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 553 static ssize_t param_attr_store(struct module_attribute *mattr,
 554                                 struct module_kobject *km,
 555                                 const char *buf, size_t len)
 556 {
 557         int err;
 558         struct param_attribute *attribute = to_param_attr(mattr);
 559
 560         if (!attribute->param->ops->set)
 561                 return -EPERM;
 562
 563         mutex_lock(&param_lock);
 564         param_check_unsafe(attribute->param);
 565         err = attribute->param->ops->set(buf, attribute->param);
 566         mutex_unlock(&param_lock);
 567         if (!err)
 568                 return len;
 569         return err;
 570 }
 571 #endif
 572
 573 #ifdef CONFIG_MODULES
 574 #define __modinit
 575 #else
 576 #define __modinit __init
 577 #endif
 578
 579 #ifdef CONFIG_SYSFS
 580 void __kernel_param_lock(void)
 581 {
 582         mutex_lock(&param_lock);
 583 }
 584 EXPORT_SYMBOL(__kernel_param_lock);
 585
 586 void __kernel_param_unlock(void)
 587 {
 588         mutex_unlock(&param_lock);
 589 }
 590 EXPORT_SYMBOL(__kernel_param_unlock);
 591
 592 /*
 593  * add_sysfs_param - add a parameter to sysfs
 594  * @mk: struct module_kobject
 595  * @kparam: the actual parameter definition to add to sysfs
 596  * @name: name of parameter
 597  *
 598  * Create a kobject if for a (per-module) parameter if mp NULL, and
 599  * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 600  * if there's an error.
 601  */
 602 static __modinit int add_sysfs_param(struct module_kobject *mk,
 603                                      const struct kernel_param *kp,
 604                                      const char *name)
 605 {
 606         struct module_param_attrs *new_mp;
 607         struct attribute **new_attrs;
 608         unsigned int i;
 609
 610         /* We don't bother calling this with invisible parameters. */
 611         BUG_ON(!kp->perm);
 612
 613         if (!mk->mp) {
 614                 /* First allocation. */
 615                 mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL);
 616                 if (!mk->mp)
 617                         return -ENOMEM;
 618                 mk->mp->grp.name = "parameters";
 619                 /* NULL-terminated attribute array. */
 620                 mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]),
 621                                             GFP_KERNEL);
 622                 /* Caller will cleanup via free_module_param_attrs */
 623                 if (!mk->mp->grp.attrs)
 624                         return -ENOMEM;
 625         }
 626
 627         /* Enlarge allocations. */
 628         new_mp = krealloc(mk->mp,
 629                           sizeof(*mk->mp) +
 630                           sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1),
 631                           GFP_KERNEL);
 632         if (!new_mp)
 633                 return -ENOMEM;
 634         mk->mp = new_mp;
 635
 636         /* Extra pointer for NULL terminator */
 637         new_attrs = krealloc(mk->mp->grp.attrs,
 638                              sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2),
 639                              GFP_KERNEL);
 640         if (!new_attrs)
 641                 return -ENOMEM;
 642         mk->mp->grp.attrs = new_attrs;
 643
 644         /* Tack new one on the end. */
 645         memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0]));
 646         sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr);
 647         mk->mp->attrs[mk->mp->num].param = kp;
 648         mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show;
 649         /* Do not allow runtime DAC changes to make param writable. */
 650         if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0)
 651                 mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store;
 652         else
 653                 mk->mp->attrs[mk->mp->num].mattr.store = NULL;
 654         mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name;
 655         mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm;
 656         mk->mp->num++;
 657
 658         /* Fix up all the pointers, since krealloc can move us */
 659         for (i = 0; i < mk->mp->num; i++)
 660                 mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr;
 661         mk->mp->grp.attrs[mk->mp->num] = NULL;
 662         return 0;
 663 }
 664
 665 #ifdef CONFIG_MODULES
 666 static void free_module_param_attrs(struct module_kobject *mk)
 667 {
 668         if (mk->mp)
 669                 kfree(mk->mp->grp.attrs);
 670         kfree(mk->mp);
 671         mk->mp = NULL;
 672 }
 673
 674 /*
 675  * module_param_sysfs_setup - setup sysfs support for one module
 676  * @mod: module
 677  * @kparam: module parameters (array)
 678  * @num_params: number of module parameters
 679  *
 680  * Adds sysfs entries for module parameters under
 681  * /sys/module/[mod->name]/parameters/
 682  */
 683 int module_param_sysfs_setup(struct module *mod,
 684                              const struct kernel_param *kparam,
 685                              unsigned int num_params)
 686 {
 687         int i, err;
 688         bool params = false;
 689
 690         for (i = 0; i < num_params; i++) {
 691                 if (kparam[i].perm == 0)
 692                         continue;
 693                 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 694                 if (err) {
 695                         free_module_param_attrs(&mod->mkobj);
 696                         return err;
 697                 }
 698                 params = true;
 699         }
 700
 701         if (!params)
 702                 return 0;
 703
 704         /* Create the param group. */
 705         err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 706         if (err)
 707                 free_module_param_attrs(&mod->mkobj);
 708         return err;
 709 }
 710
 711 /*
 712  * module_param_sysfs_remove - remove sysfs support for one module
 713  * @mod: module
 714  *
 715  * Remove sysfs entries for module parameters and the corresponding
 716  * kobject.
 717  */
 718 void module_param_sysfs_remove(struct module *mod)
 719 {
 720         if (mod->mkobj.mp) {
 721                 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 722                 /* We are positive that no one is using any param
 723                  * attrs at this point.  Deallocate immediately. */
 724                 free_module_param_attrs(&mod->mkobj);
 725         }
 726 }
 727 #endif
 728
 729 void destroy_params(const struct kernel_param *params, unsigned num)
 730 {
 731         unsigned int i;
 732
 733         for (i = 0; i < num; i++)
 734                 if (params[i].ops->free)
 735                         params[i].ops->free(params[i].arg);
 736 }
 737
 738 static struct module_kobject * __init locate_module_kobject(const char *name)
 739 {
 740         struct module_kobject *mk;
 741         struct kobject *kobj;
 742         int err;
 743
 744         kobj = kset_find_obj(module_kset, name);
 745         if (kobj) {
 746                 mk = to_module_kobject(kobj);
 747         } else {
 748                 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 749                 BUG_ON(!mk);
 750
 751                 mk->mod = THIS_MODULE;
 752                 mk->kobj.kset = module_kset;
 753                 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 754                                            "%s", name);
 755 #ifdef CONFIG_MODULES
 756                 if (!err)
 757                         err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
 758 #endif
 759                 if (err) {
 760                         kobject_put(&mk->kobj);
 761                         pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
 762                                 name, err);
 763                         return NULL;
 764                 }
 765
 766                 /* So that we hold reference in both cases. */
 767                 kobject_get(&mk->kobj);
 768         }
 769
 770         return mk;
 771 }
 772
 773 static void __init kernel_add_sysfs_param(const char *name,
 774                                           const struct kernel_param *kparam,
 775                                           unsigned int name_skip)
 776 {
 777         struct module_kobject *mk;
 778         int err;
 779
 780         mk = locate_module_kobject(name);
 781         if (!mk)
 782                 return;
 783
 784         /* We need to remove old parameters before adding more. */
 785         if (mk->mp)
 786                 sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 787
 788         /* These should not fail at boot. */
 789         err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 790         BUG_ON(err);
 791         err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 792         BUG_ON(err);
 793         kobject_uevent(&mk->kobj, KOBJ_ADD);
 794         kobject_put(&mk->kobj);
 795 }
 796
 797 /*
 798  * param_sysfs_builtin - add sysfs parameters for built-in modules
 799  *
 800  * Add module_parameters to sysfs for "modules" built into the kernel.
 801  *
 802  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 803  * "parameter" name is stored behind a dot in kernel_param->name. So,
 804  * extract the "module" name for all built-in kernel_param-eters,
 805  * and for all who have the same, call kernel_add_sysfs_param.
 806  */
 807 static void __init param_sysfs_builtin(void)
 808 {
 809         const struct kernel_param *kp;
 810         unsigned int name_len;
 811         char modname[MODULE_NAME_LEN];
 812
 813         for (kp = __start___param; kp < __stop___param; kp++) {
 814                 char *dot;
 815
 816                 if (kp->perm == 0)
 817                         continue;
 818
 819                 dot = strchr(kp->name, '.');
 820                 if (!dot) {
 821                         /* This happens for core_param() */
 822                         strcpy(modname, "kernel");
 823                         name_len = 0;
 824                 } else {
 825                         name_len = dot - kp->name + 1;
 826                         strlcpy(modname, kp->name, name_len);
 827                 }
 828                 kernel_add_sysfs_param(modname, kp, name_len);
 829         }
 830 }
 831
 832 ssize_t __modver_version_show(struct module_attribute *mattr,
 833                               struct module_kobject *mk, char *buf)
 834 {
 835         struct module_version_attribute *vattr =
 836                 container_of(mattr, struct module_version_attribute, mattr);
 837
 838         return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
 839 }
 840
 841 extern const struct module_version_attribute *__start___modver[];
 842 extern const struct module_version_attribute *__stop___modver[];
 843
 844 static void __init version_sysfs_builtin(void)
 845 {
 846         const struct module_version_attribute **p;
 847         struct module_kobject *mk;
 848         int err;
 849
 850         for (p = __start___modver; p < __stop___modver; p++) {
 851                 const struct module_version_attribute *vattr = *p;
 852
 853                 mk = locate_module_kobject(vattr->module_name);
 854                 if (mk) {
 855                         err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
 856                         kobject_uevent(&mk->kobj, KOBJ_ADD);
 857                         kobject_put(&mk->kobj);
 858                 }
 859         }
 860 }
 861
 862 /* module-related sysfs stuff */
 863
 864 static ssize_t module_attr_show(struct kobject *kobj,
 865                                 struct attribute *attr,
 866                                 char *buf)
 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->show)
 876                 return -EIO;
 877
 878         ret = attribute->show(attribute, mk, buf);
 879
 880         return ret;
 881 }
 882
 883 static ssize_t module_attr_store(struct kobject *kobj,
 884                                 struct attribute *attr,
 885                                 const char *buf, size_t len)
 886 {
 887         struct module_attribute *attribute;
 888         struct module_kobject *mk;
 889         int ret;
 890
 891         attribute = to_module_attr(attr);
 892         mk = to_module_kobject(kobj);
 893
 894         if (!attribute->store)
 895                 return -EIO;
 896
 897         ret = attribute->store(attribute, mk, buf, len);
 898
 899         return ret;
 900 }
 901
 902 static const struct sysfs_ops module_sysfs_ops = {
 903         .show = module_attr_show,
 904         .store = module_attr_store,
 905 };
 906
 907 static int uevent_filter(struct kset *kset, struct kobject *kobj)
 908 {
 909         struct kobj_type *ktype = get_ktype(kobj);
 910
 911         if (ktype == &module_ktype)
 912                 return 1;
 913         return 0;
 914 }
 915
 916 static const struct kset_uevent_ops module_uevent_ops = {
 917         .filter = uevent_filter,
 918 };
 919
 920 struct kset *module_kset;
 921 int module_sysfs_initialized;
 922
 923 static void module_kobj_release(struct kobject *kobj)
 924 {
 925         struct module_kobject *mk = to_module_kobject(kobj);
 926         complete(mk->kobj_completion);
 927 }
 928
 929 struct kobj_type module_ktype = {
 930         .release   =    module_kobj_release,
 931         .sysfs_ops =    &module_sysfs_ops,
 932 };
 933
 934 /*
 935  * param_sysfs_init - wrapper for built-in params support
 936  */
 937 static int __init param_sysfs_init(void)
 938 {
 939         module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
 940         if (!module_kset) {
 941                 printk(KERN_WARNING "%s (%d): error creating kset\n",
 942                         __FILE__, __LINE__);
 943                 return -ENOMEM;
 944         }
 945         module_sysfs_initialized = 1;
 946
 947         version_sysfs_builtin();
 948         param_sysfs_builtin();
 949
 950         return 0;
 951 }
 952 subsys_initcall(param_sysfs_init);
 953
 954 #endif /* CONFIG_SYSFS */