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/module.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 /* 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 int parse_one(char *param,
  88                      char *val,
  89                      const struct kernel_param *params,
  90                      unsigned num_params,
  91                      int (*handle_unknown)(char *param, char *val))
  92 {
  93         unsigned int i;
  94         int err;
  95
  96         /* Find parameter */
  97         for (i = 0; i < num_params; i++) {
  98                 if (parameq(param, params[i].name)) {
  99                         /* No one handled NULL, so do it here. */
 100                         if (!val && params[i].ops->set != param_set_bool)
 101                                 return -EINVAL;
 102                         pr_debug("They are equal!  Calling %p\n",
 103                                params[i].ops->set);
 104                         mutex_lock(&param_lock);
 105                         err = params[i].ops->set(val, &params[i]);
 106                         mutex_unlock(&param_lock);
 107                         return err;
 108                 }
 109         }
 110
 111         if (handle_unknown) {
 112                 pr_debug("Unknown argument: calling %p\n", handle_unknown);
 113                 return handle_unknown(param, val);
 114         }
 115
 116         pr_debug("Unknown argument `%s'\n", param);
 117         return -ENOENT;
 118 }
 119
 120 /* You can use " around spaces, but can't escape ". */
 121 /* Hyphens and underscores equivalent in parameter names. */
 122 static char *next_arg(char *args, char **param, char **val)
 123 {
 124         unsigned int i, equals = 0;
 125         int in_quote = 0, quoted = 0;
 126         char *next;
 127
 128         if (*args == '"') {
 129                 args++;
 130                 in_quote = 1;
 131                 quoted = 1;
 132         }
 133
 134         for (i = 0; args[i]; i++) {
 135                 if (isspace(args[i]) && !in_quote)
 136                         break;
 137                 if (equals == 0) {
 138                         if (args[i] == '=')
 139                                 equals = i;
 140                 }
 141                 if (args[i] == '"')
 142                         in_quote = !in_quote;
 143         }
 144
 145         *param = args;
 146         if (!equals)
 147                 *val = NULL;
 148         else {
 149                 args[equals] = '\0';
 150                 *val = args + equals + 1;
 151
 152                 /* Don't include quotes in value. */
 153                 if (**val == '"') {
 154                         (*val)++;
 155                         if (args[i-1] == '"')
 156                                 args[i-1] = '\0';
 157                 }
 158                 if (quoted && args[i-1] == '"')
 159                         args[i-1] = '\0';
 160         }
 161
 162         if (args[i]) {
 163                 args[i] = '\0';
 164                 next = args + i + 1;
 165         } else
 166                 next = args + i;
 167
 168         /* Chew up trailing spaces. */
 169         return skip_spaces(next);
 170 }
 171
 172 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 173 int parse_args(const char *name,
 174                char *args,
 175                const struct kernel_param *params,
 176                unsigned num,
 177                int (*unknown)(char *param, char *val))
 178 {
 179         char *param, *val;
 180
 181         pr_debug("Parsing ARGS: %s\n", args);
 182
 183         /* Chew leading spaces */
 184         args = skip_spaces(args);
 185
 186         while (*args) {
 187                 int ret;
 188                 int irq_was_disabled;
 189
 190                 args = next_arg(args, &param, &val);
 191                 irq_was_disabled = irqs_disabled();
 192                 ret = parse_one(param, val, params, num, unknown);
 193                 if (irq_was_disabled && !irqs_disabled()) {
 194                         printk(KERN_WARNING "parse_args(): option '%s' enabled "
 195                                         "irq's!\n", param);
 196                 }
 197                 switch (ret) {
 198                 case -ENOENT:
 199                         printk(KERN_ERR "%s: Unknown parameter `%s'\n",
 200                                name, param);
 201                         return ret;
 202                 case -ENOSPC:
 203                         printk(KERN_ERR
 204                                "%s: `%s' too large for parameter `%s'\n",
 205                                name, val ?: "", param);
 206                         return ret;
 207                 case 0:
 208                         break;
 209                 default:
 210                         printk(KERN_ERR
 211                                "%s: `%s' invalid for parameter `%s'\n",
 212                                name, val ?: "", param);
 213                         return ret;
 214                 }
 215         }
 216
 217         /* All parsed OK. */
 218         return 0;
 219 }
 220
 221 /* Lazy bastard, eh? */
 222 #define STANDARD_PARAM_DEF(name, type, format, tmptype, strtolfn)       \
 223         int param_set_##name(const char *val, const struct kernel_param *kp) \
 224         {                                                               \
 225                 tmptype l;                                              \
 226                 int ret;                                                \
 227                                                                         \
 228                 ret = strtolfn(val, 0, &l);                             \
 229                 if (ret < 0 || ((type)l != l))                          \
 230                         return ret < 0 ? ret : -EINVAL;                 \
 231                 *((type *)kp->arg) = l;                                 \
 232                 return 0;                                               \
 233         }                                                               \
 234         int param_get_##name(char *buffer, const struct kernel_param *kp) \
 235         {                                                               \
 236                 return sprintf(buffer, format, *((type *)kp->arg));     \
 237         }                                                               \
 238         struct kernel_param_ops param_ops_##name = {                    \
 239                 .set = param_set_##name,                                \
 240                 .get = param_get_##name,                                \
 241         };                                                              \
 242         EXPORT_SYMBOL(param_set_##name);                                \
 243         EXPORT_SYMBOL(param_get_##name);                                \
 244         EXPORT_SYMBOL(param_ops_##name)
 245
 246
 247 STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, strict_strtoul);
 248 STANDARD_PARAM_DEF(short, short, "%hi", long, strict_strtol);
 249 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, strict_strtoul);
 250 STANDARD_PARAM_DEF(int, int, "%i", long, strict_strtol);
 251 STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, strict_strtoul);
 252 STANDARD_PARAM_DEF(long, long, "%li", long, strict_strtol);
 253 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, strict_strtoul);
 254
 255 int param_set_charp(const char *val, const struct kernel_param *kp)
 256 {
 257         if (strlen(val) > 1024) {
 258                 printk(KERN_ERR "%s: string parameter too long\n",
 259                        kp->name);
 260                 return -ENOSPC;
 261         }
 262
 263         maybe_kfree_parameter(*(char **)kp->arg);
 264
 265         /* This is a hack.  We can't kmalloc in early boot, and we
 266          * don't need to; this mangled commandline is preserved. */
 267         if (slab_is_available()) {
 268                 *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
 269                 if (!*(char **)kp->arg)
 270                         return -ENOMEM;
 271                 strcpy(*(char **)kp->arg, val);
 272         } else
 273                 *(const char **)kp->arg = val;
 274
 275         return 0;
 276 }
 277 EXPORT_SYMBOL(param_set_charp);
 278
 279 int param_get_charp(char *buffer, const struct kernel_param *kp)
 280 {
 281         return sprintf(buffer, "%s", *((char **)kp->arg));
 282 }
 283 EXPORT_SYMBOL(param_get_charp);
 284
 285 static void param_free_charp(void *arg)
 286 {
 287         maybe_kfree_parameter(*((char **)arg));
 288 }
 289
 290 struct kernel_param_ops param_ops_charp = {
 291         .set = param_set_charp,
 292         .get = param_get_charp,
 293         .free = param_free_charp,
 294 };
 295 EXPORT_SYMBOL(param_ops_charp);
 296
 297 /* Actually could be a bool or an int, for historical reasons. */
 298 int param_set_bool(const char *val, const struct kernel_param *kp)
 299 {
 300         bool v;
 301         int ret;
 302
 303         /* No equals means "set"... */
 304         if (!val) val = "1";
 305
 306         /* One of =[yYnN01] */
 307         ret = strtobool(val, &v);
 308         if (ret)
 309                 return ret;
 310
 311         if (kp->flags & KPARAM_ISBOOL)
 312                 *(bool *)kp->arg = v;
 313         else
 314                 *(int *)kp->arg = v;
 315         return 0;
 316 }
 317 EXPORT_SYMBOL(param_set_bool);
 318
 319 int param_get_bool(char *buffer, const struct kernel_param *kp)
 320 {
 321         bool val;
 322         if (kp->flags & KPARAM_ISBOOL)
 323                 val = *(bool *)kp->arg;
 324         else
 325                 val = *(int *)kp->arg;
 326
 327         /* Y and N chosen as being relatively non-coder friendly */
 328         return sprintf(buffer, "%c", val ? 'Y' : 'N');
 329 }
 330 EXPORT_SYMBOL(param_get_bool);
 331
 332 struct kernel_param_ops param_ops_bool = {
 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         dummy.flags = KPARAM_ISBOOL;
 347         ret = param_set_bool(val, &dummy);
 348         if (ret == 0)
 349                 *(bool *)kp->arg = !boolval;
 350         return ret;
 351 }
 352 EXPORT_SYMBOL(param_set_invbool);
 353
 354 int param_get_invbool(char *buffer, const struct kernel_param *kp)
 355 {
 356         return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
 357 }
 358 EXPORT_SYMBOL(param_get_invbool);
 359
 360 struct kernel_param_ops param_ops_invbool = {
 361         .set = param_set_invbool,
 362         .get = param_get_invbool,
 363 };
 364 EXPORT_SYMBOL(param_ops_invbool);
 365
 366 int param_set_bint(const char *val, const struct kernel_param *kp)
 367 {
 368         struct kernel_param boolkp;
 369         bool v;
 370         int ret;
 371
 372         /* Match bool exactly, by re-using it. */
 373         boolkp = *kp;
 374         boolkp.arg = &v;
 375         boolkp.flags |= KPARAM_ISBOOL;
 376
 377         ret = param_set_bool(val, &boolkp);
 378         if (ret == 0)
 379                 *(int *)kp->arg = v;
 380         return ret;
 381 }
 382 EXPORT_SYMBOL(param_set_bint);
 383
 384 struct kernel_param_ops param_ops_bint = {
 385         .set = param_set_bint,
 386         .get = param_get_int,
 387 };
 388 EXPORT_SYMBOL(param_ops_bint);
 389
 390 /* We break the rule and mangle the string. */
 391 static int param_array(const char *name,
 392                        const char *val,
 393                        unsigned int min, unsigned int max,
 394                        void *elem, int elemsize,
 395                        int (*set)(const char *, const struct kernel_param *kp),
 396                        u16 flags,
 397                        unsigned int *num)
 398 {
 399         int ret;
 400         struct kernel_param kp;
 401         char save;
 402
 403         /* Get the name right for errors. */
 404         kp.name = name;
 405         kp.arg = elem;
 406         kp.flags = flags;
 407
 408         *num = 0;
 409         /* We expect a comma-separated list of values. */
 410         do {
 411                 int len;
 412
 413                 if (*num == max) {
 414                         printk(KERN_ERR "%s: can only take %i arguments\n",
 415                                name, max);
 416                         return -EINVAL;
 417                 }
 418                 len = strcspn(val, ",");
 419
 420                 /* nul-terminate and parse */
 421                 save = val[len];
 422                 ((char *)val)[len] = '\0';
 423                 BUG_ON(!mutex_is_locked(&param_lock));
 424                 ret = set(val, &kp);
 425
 426                 if (ret != 0)
 427                         return ret;
 428                 kp.arg += elemsize;
 429                 val += len+1;
 430                 (*num)++;
 431         } while (save == ',');
 432
 433         if (*num < min) {
 434                 printk(KERN_ERR "%s: needs at least %i arguments\n",
 435                        name, min);
 436                 return -EINVAL;
 437         }
 438         return 0;
 439 }
 440
 441 static int param_array_set(const char *val, const struct kernel_param *kp)
 442 {
 443         const struct kparam_array *arr = kp->arr;
 444         unsigned int temp_num;
 445
 446         return param_array(kp->name, val, 1, arr->max, arr->elem,
 447                            arr->elemsize, arr->ops->set, kp->flags,
 448                            arr->num ?: &temp_num);
 449 }
 450
 451 static int param_array_get(char *buffer, const struct kernel_param *kp)
 452 {
 453         int i, off, ret;
 454         const struct kparam_array *arr = kp->arr;
 455         struct kernel_param p;
 456
 457         p = *kp;
 458         for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 459                 if (i)
 460                         buffer[off++] = ',';
 461                 p.arg = arr->elem + arr->elemsize * i;
 462                 BUG_ON(!mutex_is_locked(&param_lock));
 463                 ret = arr->ops->get(buffer + off, &p);
 464                 if (ret < 0)
 465                         return ret;
 466                 off += ret;
 467         }
 468         buffer[off] = '\0';
 469         return off;
 470 }
 471
 472 static void param_array_free(void *arg)
 473 {
 474         unsigned int i;
 475         const struct kparam_array *arr = arg;
 476
 477         if (arr->ops->free)
 478                 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 479                         arr->ops->free(arr->elem + arr->elemsize * i);
 480 }
 481
 482 struct kernel_param_ops param_array_ops = {
 483         .set = param_array_set,
 484         .get = param_array_get,
 485         .free = param_array_free,
 486 };
 487 EXPORT_SYMBOL(param_array_ops);
 488
 489 int param_set_copystring(const char *val, const struct kernel_param *kp)
 490 {
 491         const struct kparam_string *kps = kp->str;
 492
 493         if (strlen(val)+1 > kps->maxlen) {
 494                 printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
 495                        kp->name, kps->maxlen-1);
 496                 return -ENOSPC;
 497         }
 498         strcpy(kps->string, val);
 499         return 0;
 500 }
 501 EXPORT_SYMBOL(param_set_copystring);
 502
 503 int param_get_string(char *buffer, const struct kernel_param *kp)
 504 {
 505         const struct kparam_string *kps = kp->str;
 506         return strlcpy(buffer, kps->string, kps->maxlen);
 507 }
 508 EXPORT_SYMBOL(param_get_string);
 509
 510 struct kernel_param_ops param_ops_string = {
 511         .set = param_set_copystring,
 512         .get = param_get_string,
 513 };
 514 EXPORT_SYMBOL(param_ops_string);
 515
 516 /* sysfs output in /sys/modules/XYZ/parameters/ */
 517 #define to_module_attr(n) container_of(n, struct module_attribute, attr)
 518 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 519
 520 extern struct kernel_param __start___param[], __stop___param[];
 521
 522 struct param_attribute
 523 {
 524         struct module_attribute mattr;
 525         const struct kernel_param *param;
 526 };
 527
 528 struct module_param_attrs
 529 {
 530         unsigned int num;
 531         struct attribute_group grp;
 532         struct param_attribute attrs[0];
 533 };
 534
 535 #ifdef CONFIG_SYSFS
 536 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 537
 538 static ssize_t param_attr_show(struct module_attribute *mattr,
 539                                struct module_kobject *mk, char *buf)
 540 {
 541         int count;
 542         struct param_attribute *attribute = to_param_attr(mattr);
 543
 544         if (!attribute->param->ops->get)
 545                 return -EPERM;
 546
 547         mutex_lock(&param_lock);
 548         count = attribute->param->ops->get(buf, attribute->param);
 549         mutex_unlock(&param_lock);
 550         if (count > 0) {
 551                 strcat(buf, "\n");
 552                 ++count;
 553         }
 554         return count;
 555 }
 556
 557 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 558 static ssize_t param_attr_store(struct module_attribute *mattr,
 559                                 struct module_kobject *km,
 560                                 const char *buf, size_t len)
 561 {
 562         int err;
 563         struct param_attribute *attribute = to_param_attr(mattr);
 564
 565         if (!attribute->param->ops->set)
 566                 return -EPERM;
 567
 568         mutex_lock(&param_lock);
 569         err = attribute->param->ops->set(buf, attribute->param);
 570         mutex_unlock(&param_lock);
 571         if (!err)
 572                 return len;
 573         return err;
 574 }
 575 #endif
 576
 577 #ifdef CONFIG_MODULES
 578 #define __modinit
 579 #else
 580 #define __modinit __init
 581 #endif
 582
 583 #ifdef CONFIG_SYSFS
 584 void __kernel_param_lock(void)
 585 {
 586         mutex_lock(&param_lock);
 587 }
 588 EXPORT_SYMBOL(__kernel_param_lock);
 589
 590 void __kernel_param_unlock(void)
 591 {
 592         mutex_unlock(&param_lock);
 593 }
 594 EXPORT_SYMBOL(__kernel_param_unlock);
 595
 596 /*
 597  * add_sysfs_param - add a parameter to sysfs
 598  * @mk: struct module_kobject
 599  * @kparam: the actual parameter definition to add to sysfs
 600  * @name: name of parameter
 601  *
 602  * Create a kobject if for a (per-module) parameter if mp NULL, and
 603  * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 604  * if there's an error.
 605  */
 606 static __modinit int add_sysfs_param(struct module_kobject *mk,
 607                                      const struct kernel_param *kp,
 608                                      const char *name)
 609 {
 610         struct module_param_attrs *new;
 611         struct attribute **attrs;
 612         int err, num;
 613
 614         /* We don't bother calling this with invisible parameters. */
 615         BUG_ON(!kp->perm);
 616
 617         if (!mk->mp) {
 618                 num = 0;
 619                 attrs = NULL;
 620         } else {
 621                 num = mk->mp->num;
 622                 attrs = mk->mp->grp.attrs;
 623         }
 624
 625         /* Enlarge. */
 626         new = krealloc(mk->mp,
 627                        sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
 628                        GFP_KERNEL);
 629         if (!new) {
 630                 kfree(mk->mp);
 631                 err = -ENOMEM;
 632                 goto fail;
 633         }
 634         attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
 635         if (!attrs) {
 636                 err = -ENOMEM;
 637                 goto fail_free_new;
 638         }
 639
 640         /* Sysfs wants everything zeroed. */
 641         memset(new, 0, sizeof(*new));
 642         memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
 643         memset(&attrs[num], 0, sizeof(attrs[num]));
 644         new->grp.name = "parameters";
 645         new->grp.attrs = attrs;
 646
 647         /* Tack new one on the end. */
 648         sysfs_attr_init(&new->attrs[num].mattr.attr);
 649         new->attrs[num].param = kp;
 650         new->attrs[num].mattr.show = param_attr_show;
 651         new->attrs[num].mattr.store = param_attr_store;
 652         new->attrs[num].mattr.attr.name = (char *)name;
 653         new->attrs[num].mattr.attr.mode = kp->perm;
 654         new->num = num+1;
 655
 656         /* Fix up all the pointers, since krealloc can move us */
 657         for (num = 0; num < new->num; num++)
 658                 new->grp.attrs[num] = &new->attrs[num].mattr.attr;
 659         new->grp.attrs[num] = NULL;
 660
 661         mk->mp = new;
 662         return 0;
 663
 664 fail_free_new:
 665         kfree(new);
 666 fail:
 667         mk->mp = NULL;
 668         return err;
 669 }
 670
 671 #ifdef CONFIG_MODULES
 672 static void free_module_param_attrs(struct module_kobject *mk)
 673 {
 674         kfree(mk->mp->grp.attrs);
 675         kfree(mk->mp);
 676         mk->mp = NULL;
 677 }
 678
 679 /*
 680  * module_param_sysfs_setup - setup sysfs support for one module
 681  * @mod: module
 682  * @kparam: module parameters (array)
 683  * @num_params: number of module parameters
 684  *
 685  * Adds sysfs entries for module parameters under
 686  * /sys/module/[mod->name]/parameters/
 687  */
 688 int module_param_sysfs_setup(struct module *mod,
 689                              const struct kernel_param *kparam,
 690                              unsigned int num_params)
 691 {
 692         int i, err;
 693         bool params = false;
 694
 695         for (i = 0; i < num_params; i++) {
 696                 if (kparam[i].perm == 0)
 697                         continue;
 698                 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 699                 if (err)
 700                         return err;
 701                 params = true;
 702         }
 703
 704         if (!params)
 705                 return 0;
 706
 707         /* Create the param group. */
 708         err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 709         if (err)
 710                 free_module_param_attrs(&mod->mkobj);
 711         return err;
 712 }
 713
 714 /*
 715  * module_param_sysfs_remove - remove sysfs support for one module
 716  * @mod: module
 717  *
 718  * Remove sysfs entries for module parameters and the corresponding
 719  * kobject.
 720  */
 721 void module_param_sysfs_remove(struct module *mod)
 722 {
 723         if (mod->mkobj.mp) {
 724                 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 725                 /* We are positive that no one is using any param
 726                  * attrs at this point.  Deallocate immediately. */
 727                 free_module_param_attrs(&mod->mkobj);
 728         }
 729 }
 730 #endif
 731
 732 void destroy_params(const struct kernel_param *params, unsigned num)
 733 {
 734         unsigned int i;
 735
 736         for (i = 0; i < num; i++)
 737                 if (params[i].ops->free)
 738                         params[i].ops->free(params[i].arg);
 739 }
 740
 741 static struct module_kobject * __init locate_module_kobject(const char *name)
 742 {
 743         struct module_kobject *mk;
 744         struct kobject *kobj;
 745         int err;
 746
 747         kobj = kset_find_obj(module_kset, name);
 748         if (kobj) {
 749                 mk = to_module_kobject(kobj);
 750         } else {
 751                 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 752                 BUG_ON(!mk);
 753
 754                 mk->mod = THIS_MODULE;
 755                 mk->kobj.kset = module_kset;
 756                 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 757                                            "%s", name);
 758 #ifdef CONFIG_MODULES
 759                 if (!err)
 760                         err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
 761 #endif
 762                 if (err) {
 763                         kobject_put(&mk->kobj);
 764                         printk(KERN_ERR
 765                                 "Module '%s' failed add to sysfs, error number %d\n",
 766                                 name, err);
 767                         printk(KERN_ERR
 768                                 "The system will be unstable now.\n");
 769                         return NULL;
 770                 }
 771
 772                 /* So that we hold reference in both cases. */
 773                 kobject_get(&mk->kobj);
 774         }
 775
 776         return mk;
 777 }
 778
 779 static void __init kernel_add_sysfs_param(const char *name,
 780                                           struct kernel_param *kparam,
 781                                           unsigned int name_skip)
 782 {
 783         struct module_kobject *mk;
 784         int err;
 785
 786         mk = locate_module_kobject(name);
 787         if (!mk)
 788                 return;
 789
 790         /* We need to remove old parameters before adding more. */
 791         if (mk->mp)
 792                 sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 793
 794         /* These should not fail at boot. */
 795         err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 796         BUG_ON(err);
 797         err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 798         BUG_ON(err);
 799         kobject_uevent(&mk->kobj, KOBJ_ADD);
 800         kobject_put(&mk->kobj);
 801 }
 802
 803 /*
 804  * param_sysfs_builtin - add contents in /sys/parameters for built-in modules
 805  *
 806  * Add module_parameters to sysfs for "modules" built into the kernel.
 807  *
 808  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 809  * "parameter" name is stored behind a dot in kernel_param->name. So,
 810  * extract the "module" name for all built-in kernel_param-eters,
 811  * and for all who have the same, call kernel_add_sysfs_param.
 812  */
 813 static void __init param_sysfs_builtin(void)
 814 {
 815         struct kernel_param *kp;
 816         unsigned int name_len;
 817         char modname[MODULE_NAME_LEN];
 818
 819         for (kp = __start___param; kp < __stop___param; kp++) {
 820                 char *dot;
 821
 822                 if (kp->perm == 0)
 823                         continue;
 824
 825                 dot = strchr(kp->name, '.');
 826                 if (!dot) {
 827                         /* This happens for core_param() */
 828                         strcpy(modname, "kernel");
 829                         name_len = 0;
 830                 } else {
 831                         name_len = dot - kp->name + 1;
 832                         strlcpy(modname, kp->name, name_len);
 833                 }
 834                 kernel_add_sysfs_param(modname, kp, name_len);
 835         }
 836 }
 837
 838 ssize_t __modver_version_show(struct module_attribute *mattr,
 839                               struct module_kobject *mk, char *buf)
 840 {
 841         struct module_version_attribute *vattr =
 842                 container_of(mattr, struct module_version_attribute, mattr);
 843
 844         return sprintf(buf, "%s\n", vattr->version);
 845 }
 846
 847 extern const struct module_version_attribute *__start___modver[];
 848 extern const struct module_version_attribute *__stop___modver[];
 849
 850 static void __init version_sysfs_builtin(void)
 851 {
 852         const struct module_version_attribute **p;
 853         struct module_kobject *mk;
 854         int err;
 855
 856         for (p = __start___modver; p < __stop___modver; p++) {
 857                 const struct module_version_attribute *vattr = *p;
 858
 859                 mk = locate_module_kobject(vattr->module_name);
 860                 if (mk) {
 861                         err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
 862                         kobject_uevent(&mk->kobj, KOBJ_ADD);
 863                         kobject_put(&mk->kobj);
 864                 }
 865         }
 866 }
 867
 868 /* module-related sysfs stuff */
 869
 870 static ssize_t module_attr_show(struct kobject *kobj,
 871                                 struct attribute *attr,
 872                                 char *buf)
 873 {
 874         struct module_attribute *attribute;
 875         struct module_kobject *mk;
 876         int ret;
 877
 878         attribute = to_module_attr(attr);
 879         mk = to_module_kobject(kobj);
 880
 881         if (!attribute->show)
 882                 return -EIO;
 883
 884         ret = attribute->show(attribute, mk, buf);
 885
 886         return ret;
 887 }
 888
 889 static ssize_t module_attr_store(struct kobject *kobj,
 890                                 struct attribute *attr,
 891                                 const char *buf, size_t len)
 892 {
 893         struct module_attribute *attribute;
 894         struct module_kobject *mk;
 895         int ret;
 896
 897         attribute = to_module_attr(attr);
 898         mk = to_module_kobject(kobj);
 899
 900         if (!attribute->store)
 901                 return -EIO;
 902
 903         ret = attribute->store(attribute, mk, buf, len);
 904
 905         return ret;
 906 }
 907
 908 static const struct sysfs_ops module_sysfs_ops = {
 909         .show = module_attr_show,
 910         .store = module_attr_store,
 911 };
 912
 913 static int uevent_filter(struct kset *kset, struct kobject *kobj)
 914 {
 915         struct kobj_type *ktype = get_ktype(kobj);
 916
 917         if (ktype == &module_ktype)
 918                 return 1;
 919         return 0;
 920 }
 921
 922 static const struct kset_uevent_ops module_uevent_ops = {
 923         .filter = uevent_filter,
 924 };
 925
 926 struct kset *module_kset;
 927 int module_sysfs_initialized;
 928
 929 struct kobj_type module_ktype = {
 930         .sysfs_ops =    &module_sysfs_ops,
 931 };
 932
 933 /*
 934  * param_sysfs_init - wrapper for built-in params support
 935  */
 936 static int __init param_sysfs_init(void)
 937 {
 938         module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
 939         if (!module_kset) {
 940                 printk(KERN_WARNING "%s (%d): error creating kset\n",
 941                         __FILE__, __LINE__);
 942                 return -ENOMEM;
 943         }
 944         module_sysfs_initialized = 1;
 945
 946         version_sysfs_builtin();
 947         param_sysfs_builtin();
 948
 949         return 0;
 950 }
 951 subsys_initcall(param_sysfs_init);
 952
 953 #endif /* CONFIG_SYSFS */