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                             && params[i].ops->set != param_set_bint)
 102                                 return -EINVAL;
 103                         pr_debug("They are equal!  Calling %p\n",
 104                                params[i].ops->set);
 105                         mutex_lock(&param_lock);
 106                         err = params[i].ops->set(val, &params[i]);
 107                         mutex_unlock(&param_lock);
 108                         return err;
 109                 }
 110         }
 111
 112         if (handle_unknown) {
 113                 pr_debug("Unknown argument: calling %p\n", handle_unknown);
 114                 return handle_unknown(param, val);
 115         }
 116
 117         pr_debug("Unknown argument `%s'\n", param);
 118         return -ENOENT;
 119 }
 120
 121 /* You can use " around spaces, but can't escape ". */
 122 /* Hyphens and underscores equivalent in parameter names. */
 123 static char *next_arg(char *args, char **param, char **val)
 124 {
 125         unsigned int i, equals = 0;
 126         int in_quote = 0, quoted = 0;
 127         char *next;
 128
 129         if (*args == '"') {
 130                 args++;
 131                 in_quote = 1;
 132                 quoted = 1;
 133         }
 134
 135         for (i = 0; args[i]; i++) {
 136                 if (isspace(args[i]) && !in_quote)
 137                         break;
 138                 if (equals == 0) {
 139                         if (args[i] == '=')
 140                                 equals = i;
 141                 }
 142                 if (args[i] == '"')
 143                         in_quote = !in_quote;
 144         }
 145
 146         *param = args;
 147         if (!equals)
 148                 *val = NULL;
 149         else {
 150                 args[equals] = '\0';
 151                 *val = args + equals + 1;
 152
 153                 /* Don't include quotes in value. */
 154                 if (**val == '"') {
 155                         (*val)++;
 156                         if (args[i-1] == '"')
 157                                 args[i-1] = '\0';
 158                 }
 159                 if (quoted && args[i-1] == '"')
 160                         args[i-1] = '\0';
 161         }
 162
 163         if (args[i]) {
 164                 args[i] = '\0';
 165                 next = args + i + 1;
 166         } else
 167                 next = args + i;
 168
 169         /* Chew up trailing spaces. */
 170         return skip_spaces(next);
 171 }
 172
 173 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 174 int parse_args(const char *name,
 175                char *args,
 176                const struct kernel_param *params,
 177                unsigned num,
 178                int (*unknown)(char *param, char *val))
 179 {
 180         char *param, *val;
 181
 182         pr_debug("Parsing ARGS: %s\n", args);
 183
 184         /* Chew leading spaces */
 185         args = skip_spaces(args);
 186
 187         while (*args) {
 188                 int ret;
 189                 int irq_was_disabled;
 190
 191                 args = next_arg(args, &param, &val);
 192                 irq_was_disabled = irqs_disabled();
 193                 ret = parse_one(param, val, params, num, unknown);
 194                 if (irq_was_disabled && !irqs_disabled()) {
 195                         printk(KERN_WARNING "parse_args(): option '%s' enabled "
 196                                         "irq's!\n", param);
 197                 }
 198                 switch (ret) {
 199                 case -ENOENT:
 200                         printk(KERN_ERR "%s: Unknown parameter `%s'\n",
 201                                name, param);
 202                         return ret;
 203                 case -ENOSPC:
 204                         printk(KERN_ERR
 205                                "%s: `%s' too large for parameter `%s'\n",
 206                                name, val ?: "", param);
 207                         return ret;
 208                 case 0:
 209                         break;
 210                 default:
 211                         printk(KERN_ERR
 212                                "%s: `%s' invalid for parameter `%s'\n",
 213                                name, val ?: "", param);
 214                         return ret;
 215                 }
 216         }
 217
 218         /* All parsed OK. */
 219         return 0;
 220 }
 221
 222 /* Lazy bastard, eh? */
 223 #define STANDARD_PARAM_DEF(name, type, format, tmptype, strtolfn)       \
 224         int param_set_##name(const char *val, const struct kernel_param *kp) \
 225         {                                                               \
 226                 tmptype l;                                              \
 227                 int ret;                                                \
 228                                                                         \
 229                 ret = strtolfn(val, 0, &l);                             \
 230                 if (ret < 0 || ((type)l != l))                          \
 231                         return ret < 0 ? ret : -EINVAL;                 \
 232                 *((type *)kp->arg) = l;                                 \
 233                 return 0;                                               \
 234         }                                                               \
 235         int param_get_##name(char *buffer, const struct kernel_param *kp) \
 236         {                                                               \
 237                 return sprintf(buffer, format, *((type *)kp->arg));     \
 238         }                                                               \
 239         struct kernel_param_ops param_ops_##name = {                    \
 240                 .set = param_set_##name,                                \
 241                 .get = param_get_##name,                                \
 242         };                                                              \
 243         EXPORT_SYMBOL(param_set_##name);                                \
 244         EXPORT_SYMBOL(param_get_##name);                                \
 245         EXPORT_SYMBOL(param_ops_##name)
 246
 247
 248 STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, strict_strtoul);
 249 STANDARD_PARAM_DEF(short, short, "%hi", long, strict_strtol);
 250 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, strict_strtoul);
 251 STANDARD_PARAM_DEF(int, int, "%i", long, strict_strtol);
 252 STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, strict_strtoul);
 253 STANDARD_PARAM_DEF(long, long, "%li", long, strict_strtol);
 254 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, strict_strtoul);
 255
 256 int param_set_charp(const char *val, const struct kernel_param *kp)
 257 {
 258         if (strlen(val) > 1024) {
 259                 printk(KERN_ERR "%s: string parameter too long\n",
 260                        kp->name);
 261                 return -ENOSPC;
 262         }
 263
 264         maybe_kfree_parameter(*(char **)kp->arg);
 265
 266         /* This is a hack.  We can't kmalloc in early boot, and we
 267          * don't need to; this mangled commandline is preserved. */
 268         if (slab_is_available()) {
 269                 *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
 270                 if (!*(char **)kp->arg)
 271                         return -ENOMEM;
 272                 strcpy(*(char **)kp->arg, val);
 273         } else
 274                 *(const char **)kp->arg = val;
 275
 276         return 0;
 277 }
 278 EXPORT_SYMBOL(param_set_charp);
 279
 280 int param_get_charp(char *buffer, const struct kernel_param *kp)
 281 {
 282         return sprintf(buffer, "%s", *((char **)kp->arg));
 283 }
 284 EXPORT_SYMBOL(param_get_charp);
 285
 286 static void param_free_charp(void *arg)
 287 {
 288         maybe_kfree_parameter(*((char **)arg));
 289 }
 290
 291 struct kernel_param_ops param_ops_charp = {
 292         .set = param_set_charp,
 293         .get = param_get_charp,
 294         .free = param_free_charp,
 295 };
 296 EXPORT_SYMBOL(param_ops_charp);
 297
 298 /* Actually could be a bool or an int, for historical reasons. */
 299 int param_set_bool(const char *val, const struct kernel_param *kp)
 300 {
 301         bool v;
 302         int ret;
 303
 304         /* No equals means "set"... */
 305         if (!val) val = "1";
 306
 307         /* One of =[yYnN01] */
 308         ret = strtobool(val, &v);
 309         if (ret)
 310                 return ret;
 311
 312         if (kp->flags & KPARAM_ISBOOL)
 313                 *(bool *)kp->arg = v;
 314         else
 315                 *(int *)kp->arg = v;
 316         return 0;
 317 }
 318 EXPORT_SYMBOL(param_set_bool);
 319
 320 int param_get_bool(char *buffer, const struct kernel_param *kp)
 321 {
 322         bool val;
 323         if (kp->flags & KPARAM_ISBOOL)
 324                 val = *(bool *)kp->arg;
 325         else
 326                 val = *(int *)kp->arg;
 327
 328         /* Y and N chosen as being relatively non-coder friendly */
 329         return sprintf(buffer, "%c", val ? 'Y' : 'N');
 330 }
 331 EXPORT_SYMBOL(param_get_bool);
 332
 333 struct kernel_param_ops param_ops_bool = {
 334         .set = param_set_bool,
 335         .get = param_get_bool,
 336 };
 337 EXPORT_SYMBOL(param_ops_bool);
 338
 339 /* This one must be bool. */
 340 int param_set_invbool(const char *val, const struct kernel_param *kp)
 341 {
 342         int ret;
 343         bool boolval;
 344         struct kernel_param dummy;
 345
 346         dummy.arg = &boolval;
 347         dummy.flags = KPARAM_ISBOOL;
 348         ret = param_set_bool(val, &dummy);
 349         if (ret == 0)
 350                 *(bool *)kp->arg = !boolval;
 351         return ret;
 352 }
 353 EXPORT_SYMBOL(param_set_invbool);
 354
 355 int param_get_invbool(char *buffer, const struct kernel_param *kp)
 356 {
 357         return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
 358 }
 359 EXPORT_SYMBOL(param_get_invbool);
 360
 361 struct kernel_param_ops param_ops_invbool = {
 362         .set = param_set_invbool,
 363         .get = param_get_invbool,
 364 };
 365 EXPORT_SYMBOL(param_ops_invbool);
 366
 367 int param_set_bint(const char *val, const struct kernel_param *kp)
 368 {
 369         struct kernel_param boolkp;
 370         bool v;
 371         int ret;
 372
 373         /* Match bool exactly, by re-using it. */
 374         boolkp = *kp;
 375         boolkp.arg = &v;
 376         boolkp.flags |= KPARAM_ISBOOL;
 377
 378         ret = param_set_bool(val, &boolkp);
 379         if (ret == 0)
 380                 *(int *)kp->arg = v;
 381         return ret;
 382 }
 383 EXPORT_SYMBOL(param_set_bint);
 384
 385 struct kernel_param_ops param_ops_bint = {
 386         .set = param_set_bint,
 387         .get = param_get_int,
 388 };
 389 EXPORT_SYMBOL(param_ops_bint);
 390
 391 /* We break the rule and mangle the string. */
 392 static int param_array(const char *name,
 393                        const char *val,
 394                        unsigned int min, unsigned int max,
 395                        void *elem, int elemsize,
 396                        int (*set)(const char *, const struct kernel_param *kp),
 397                        u16 flags,
 398                        unsigned int *num)
 399 {
 400         int ret;
 401         struct kernel_param kp;
 402         char save;
 403
 404         /* Get the name right for errors. */
 405         kp.name = name;
 406         kp.arg = elem;
 407         kp.flags = flags;
 408
 409         *num = 0;
 410         /* We expect a comma-separated list of values. */
 411         do {
 412                 int len;
 413
 414                 if (*num == max) {
 415                         printk(KERN_ERR "%s: can only take %i arguments\n",
 416                                name, max);
 417                         return -EINVAL;
 418                 }
 419                 len = strcspn(val, ",");
 420
 421                 /* nul-terminate and parse */
 422                 save = val[len];
 423                 ((char *)val)[len] = '\0';
 424                 BUG_ON(!mutex_is_locked(&param_lock));
 425                 ret = set(val, &kp);
 426
 427                 if (ret != 0)
 428                         return ret;
 429                 kp.arg += elemsize;
 430                 val += len+1;
 431                 (*num)++;
 432         } while (save == ',');
 433
 434         if (*num < min) {
 435                 printk(KERN_ERR "%s: needs at least %i arguments\n",
 436                        name, min);
 437                 return -EINVAL;
 438         }
 439         return 0;
 440 }
 441
 442 static int param_array_set(const char *val, const struct kernel_param *kp)
 443 {
 444         const struct kparam_array *arr = kp->arr;
 445         unsigned int temp_num;
 446
 447         return param_array(kp->name, val, 1, arr->max, arr->elem,
 448                            arr->elemsize, arr->ops->set, kp->flags,
 449                            arr->num ?: &temp_num);
 450 }
 451
 452 static int param_array_get(char *buffer, const struct kernel_param *kp)
 453 {
 454         int i, off, ret;
 455         const struct kparam_array *arr = kp->arr;
 456         struct kernel_param p;
 457
 458         p = *kp;
 459         for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 460                 if (i)
 461                         buffer[off++] = ',';
 462                 p.arg = arr->elem + arr->elemsize * i;
 463                 BUG_ON(!mutex_is_locked(&param_lock));
 464                 ret = arr->ops->get(buffer + off, &p);
 465                 if (ret < 0)
 466                         return ret;
 467                 off += ret;
 468         }
 469         buffer[off] = '\0';
 470         return off;
 471 }
 472
 473 static void param_array_free(void *arg)
 474 {
 475         unsigned int i;
 476         const struct kparam_array *arr = arg;
 477
 478         if (arr->ops->free)
 479                 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 480                         arr->ops->free(arr->elem + arr->elemsize * i);
 481 }
 482
 483 struct kernel_param_ops param_array_ops = {
 484         .set = param_array_set,
 485         .get = param_array_get,
 486         .free = param_array_free,
 487 };
 488 EXPORT_SYMBOL(param_array_ops);
 489
 490 int param_set_copystring(const char *val, const struct kernel_param *kp)
 491 {
 492         const struct kparam_string *kps = kp->str;
 493
 494         if (strlen(val)+1 > kps->maxlen) {
 495                 printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
 496                        kp->name, kps->maxlen-1);
 497                 return -ENOSPC;
 498         }
 499         strcpy(kps->string, val);
 500         return 0;
 501 }
 502 EXPORT_SYMBOL(param_set_copystring);
 503
 504 int param_get_string(char *buffer, const struct kernel_param *kp)
 505 {
 506         const struct kparam_string *kps = kp->str;
 507         return strlcpy(buffer, kps->string, kps->maxlen);
 508 }
 509 EXPORT_SYMBOL(param_get_string);
 510
 511 struct kernel_param_ops param_ops_string = {
 512         .set = param_set_copystring,
 513         .get = param_get_string,
 514 };
 515 EXPORT_SYMBOL(param_ops_string);
 516
 517 /* sysfs output in /sys/modules/XYZ/parameters/ */
 518 #define to_module_attr(n) container_of(n, struct module_attribute, attr)
 519 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 520
 521 extern struct kernel_param __start___param[], __stop___param[];
 522
 523 struct param_attribute
 524 {
 525         struct module_attribute mattr;
 526         const struct kernel_param *param;
 527 };
 528
 529 struct module_param_attrs
 530 {
 531         unsigned int num;
 532         struct attribute_group grp;
 533         struct param_attribute attrs[0];
 534 };
 535
 536 #ifdef CONFIG_SYSFS
 537 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 538
 539 static ssize_t param_attr_show(struct module_attribute *mattr,
 540                                struct module_kobject *mk, char *buf)
 541 {
 542         int count;
 543         struct param_attribute *attribute = to_param_attr(mattr);
 544
 545         if (!attribute->param->ops->get)
 546                 return -EPERM;
 547
 548         mutex_lock(&param_lock);
 549         count = attribute->param->ops->get(buf, attribute->param);
 550         mutex_unlock(&param_lock);
 551         if (count > 0) {
 552                 strcat(buf, "\n");
 553                 ++count;
 554         }
 555         return count;
 556 }
 557
 558 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 559 static ssize_t param_attr_store(struct module_attribute *mattr,
 560                                 struct module_kobject *km,
 561                                 const char *buf, size_t len)
 562 {
 563         int err;
 564         struct param_attribute *attribute = to_param_attr(mattr);
 565
 566         if (!attribute->param->ops->set)
 567                 return -EPERM;
 568
 569         mutex_lock(&param_lock);
 570         err = attribute->param->ops->set(buf, attribute->param);
 571         mutex_unlock(&param_lock);
 572         if (!err)
 573                 return len;
 574         return err;
 575 }
 576 #endif
 577
 578 #ifdef CONFIG_MODULES
 579 #define __modinit
 580 #else
 581 #define __modinit __init
 582 #endif
 583
 584 #ifdef CONFIG_SYSFS
 585 void __kernel_param_lock(void)
 586 {
 587         mutex_lock(&param_lock);
 588 }
 589 EXPORT_SYMBOL(__kernel_param_lock);
 590
 591 void __kernel_param_unlock(void)
 592 {
 593         mutex_unlock(&param_lock);
 594 }
 595 EXPORT_SYMBOL(__kernel_param_unlock);
 596
 597 /*
 598  * add_sysfs_param - add a parameter to sysfs
 599  * @mk: struct module_kobject
 600  * @kparam: the actual parameter definition to add to sysfs
 601  * @name: name of parameter
 602  *
 603  * Create a kobject if for a (per-module) parameter if mp NULL, and
 604  * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 605  * if there's an error.
 606  */
 607 static __modinit int add_sysfs_param(struct module_kobject *mk,
 608                                      const struct kernel_param *kp,
 609                                      const char *name)
 610 {
 611         struct module_param_attrs *new;
 612         struct attribute **attrs;
 613         int err, num;
 614
 615         /* We don't bother calling this with invisible parameters. */
 616         BUG_ON(!kp->perm);
 617
 618         if (!mk->mp) {
 619                 num = 0;
 620                 attrs = NULL;
 621         } else {
 622                 num = mk->mp->num;
 623                 attrs = mk->mp->grp.attrs;
 624         }
 625
 626         /* Enlarge. */
 627         new = krealloc(mk->mp,
 628                        sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
 629                        GFP_KERNEL);
 630         if (!new) {
 631                 kfree(mk->mp);
 632                 err = -ENOMEM;
 633                 goto fail;
 634         }
 635         attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
 636         if (!attrs) {
 637                 err = -ENOMEM;
 638                 goto fail_free_new;
 639         }
 640
 641         /* Sysfs wants everything zeroed. */
 642         memset(new, 0, sizeof(*new));
 643         memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
 644         memset(&attrs[num], 0, sizeof(attrs[num]));
 645         new->grp.name = "parameters";
 646         new->grp.attrs = attrs;
 647
 648         /* Tack new one on the end. */
 649         sysfs_attr_init(&new->attrs[num].mattr.attr);
 650         new->attrs[num].param = kp;
 651         new->attrs[num].mattr.show = param_attr_show;
 652         new->attrs[num].mattr.store = param_attr_store;
 653         new->attrs[num].mattr.attr.name = (char *)name;
 654         new->attrs[num].mattr.attr.mode = kp->perm;
 655         new->num = num+1;
 656
 657         /* Fix up all the pointers, since krealloc can move us */
 658         for (num = 0; num < new->num; num++)
 659                 new->grp.attrs[num] = &new->attrs[num].mattr.attr;
 660         new->grp.attrs[num] = NULL;
 661
 662         mk->mp = new;
 663         return 0;
 664
 665 fail_free_new:
 666         kfree(new);
 667 fail:
 668         mk->mp = NULL;
 669         return err;
 670 }
 671
 672 #ifdef CONFIG_MODULES
 673 static void free_module_param_attrs(struct module_kobject *mk)
 674 {
 675         kfree(mk->mp->grp.attrs);
 676         kfree(mk->mp);
 677         mk->mp = NULL;
 678 }
 679
 680 /*
 681  * module_param_sysfs_setup - setup sysfs support for one module
 682  * @mod: module
 683  * @kparam: module parameters (array)
 684  * @num_params: number of module parameters
 685  *
 686  * Adds sysfs entries for module parameters under
 687  * /sys/module/[mod->name]/parameters/
 688  */
 689 int module_param_sysfs_setup(struct module *mod,
 690                              const struct kernel_param *kparam,
 691                              unsigned int num_params)
 692 {
 693         int i, err;
 694         bool params = false;
 695
 696         for (i = 0; i < num_params; i++) {
 697                 if (kparam[i].perm == 0)
 698                         continue;
 699                 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 700                 if (err)
 701                         return err;
 702                 params = true;
 703         }
 704
 705         if (!params)
 706                 return 0;
 707
 708         /* Create the param group. */
 709         err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 710         if (err)
 711                 free_module_param_attrs(&mod->mkobj);
 712         return err;
 713 }
 714
 715 /*
 716  * module_param_sysfs_remove - remove sysfs support for one module
 717  * @mod: module
 718  *
 719  * Remove sysfs entries for module parameters and the corresponding
 720  * kobject.
 721  */
 722 void module_param_sysfs_remove(struct module *mod)
 723 {
 724         if (mod->mkobj.mp) {
 725                 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 726                 /* We are positive that no one is using any param
 727                  * attrs at this point.  Deallocate immediately. */
 728                 free_module_param_attrs(&mod->mkobj);
 729         }
 730 }
 731 #endif
 732
 733 void destroy_params(const struct kernel_param *params, unsigned num)
 734 {
 735         unsigned int i;
 736
 737         for (i = 0; i < num; i++)
 738                 if (params[i].ops->free)
 739                         params[i].ops->free(params[i].arg);
 740 }
 741
 742 static struct module_kobject * __init locate_module_kobject(const char *name)
 743 {
 744         struct module_kobject *mk;
 745         struct kobject *kobj;
 746         int err;
 747
 748         kobj = kset_find_obj(module_kset, name);
 749         if (kobj) {
 750                 mk = to_module_kobject(kobj);
 751         } else {
 752                 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 753                 BUG_ON(!mk);
 754
 755                 mk->mod = THIS_MODULE;
 756                 mk->kobj.kset = module_kset;
 757                 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 758                                            "%s", name);
 759 #ifdef CONFIG_MODULES
 760                 if (!err)
 761                         err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
 762 #endif
 763                 if (err) {
 764                         kobject_put(&mk->kobj);
 765                         printk(KERN_ERR
 766                                 "Module '%s' failed add to sysfs, error number %d\n",
 767                                 name, err);
 768                         printk(KERN_ERR
 769                                 "The system will be unstable now.\n");
 770                         return NULL;
 771                 }
 772
 773                 /* So that we hold reference in both cases. */
 774                 kobject_get(&mk->kobj);
 775         }
 776
 777         return mk;
 778 }
 779
 780 static void __init kernel_add_sysfs_param(const char *name,
 781                                           struct kernel_param *kparam,
 782                                           unsigned int name_skip)
 783 {
 784         struct module_kobject *mk;
 785         int err;
 786
 787         mk = locate_module_kobject(name);
 788         if (!mk)
 789                 return;
 790
 791         /* We need to remove old parameters before adding more. */
 792         if (mk->mp)
 793                 sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 794
 795         /* These should not fail at boot. */
 796         err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 797         BUG_ON(err);
 798         err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 799         BUG_ON(err);
 800         kobject_uevent(&mk->kobj, KOBJ_ADD);
 801         kobject_put(&mk->kobj);
 802 }
 803
 804 /*
 805  * param_sysfs_builtin - add contents in /sys/parameters for built-in modules
 806  *
 807  * Add module_parameters to sysfs for "modules" built into the kernel.
 808  *
 809  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 810  * "parameter" name is stored behind a dot in kernel_param->name. So,
 811  * extract the "module" name for all built-in kernel_param-eters,
 812  * and for all who have the same, call kernel_add_sysfs_param.
 813  */
 814 static void __init param_sysfs_builtin(void)
 815 {
 816         struct kernel_param *kp;
 817         unsigned int name_len;
 818         char modname[MODULE_NAME_LEN];
 819
 820         for (kp = __start___param; kp < __stop___param; kp++) {
 821                 char *dot;
 822
 823                 if (kp->perm == 0)
 824                         continue;
 825
 826                 dot = strchr(kp->name, '.');
 827                 if (!dot) {
 828                         /* This happens for core_param() */
 829                         strcpy(modname, "kernel");
 830                         name_len = 0;
 831                 } else {
 832                         name_len = dot - kp->name + 1;
 833                         strlcpy(modname, kp->name, name_len);
 834                 }
 835                 kernel_add_sysfs_param(modname, kp, name_len);
 836         }
 837 }
 838
 839 ssize_t __modver_version_show(struct module_attribute *mattr,
 840                               struct module_kobject *mk, char *buf)
 841 {
 842         struct module_version_attribute *vattr =
 843                 container_of(mattr, struct module_version_attribute, mattr);
 844
 845         return sprintf(buf, "%s\n", vattr->version);
 846 }
 847
 848 extern const struct module_version_attribute *__start___modver[];
 849 extern const struct module_version_attribute *__stop___modver[];
 850
 851 static void __init version_sysfs_builtin(void)
 852 {
 853         const struct module_version_attribute **p;
 854         struct module_kobject *mk;
 855         int err;
 856
 857         for (p = __start___modver; p < __stop___modver; p++) {
 858                 const struct module_version_attribute *vattr = *p;
 859
 860                 mk = locate_module_kobject(vattr->module_name);
 861                 if (mk) {
 862                         err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
 863                         kobject_uevent(&mk->kobj, KOBJ_ADD);
 864                         kobject_put(&mk->kobj);
 865                 }
 866         }
 867 }
 868
 869 /* module-related sysfs stuff */
 870
 871 static ssize_t module_attr_show(struct kobject *kobj,
 872                                 struct attribute *attr,
 873                                 char *buf)
 874 {
 875         struct module_attribute *attribute;
 876         struct module_kobject *mk;
 877         int ret;
 878
 879         attribute = to_module_attr(attr);
 880         mk = to_module_kobject(kobj);
 881
 882         if (!attribute->show)
 883                 return -EIO;
 884
 885         ret = attribute->show(attribute, mk, buf);
 886
 887         return ret;
 888 }
 889
 890 static ssize_t module_attr_store(struct kobject *kobj,
 891                                 struct attribute *attr,
 892                                 const char *buf, size_t len)
 893 {
 894         struct module_attribute *attribute;
 895         struct module_kobject *mk;
 896         int ret;
 897
 898         attribute = to_module_attr(attr);
 899         mk = to_module_kobject(kobj);
 900
 901         if (!attribute->store)
 902                 return -EIO;
 903
 904         ret = attribute->store(attribute, mk, buf, len);
 905
 906         return ret;
 907 }
 908
 909 static const struct sysfs_ops module_sysfs_ops = {
 910         .show = module_attr_show,
 911         .store = module_attr_store,
 912 };
 913
 914 static int uevent_filter(struct kset *kset, struct kobject *kobj)
 915 {
 916         struct kobj_type *ktype = get_ktype(kobj);
 917
 918         if (ktype == &module_ktype)
 919                 return 1;
 920         return 0;
 921 }
 922
 923 static const struct kset_uevent_ops module_uevent_ops = {
 924         .filter = uevent_filter,
 925 };
 926
 927 struct kset *module_kset;
 928 int module_sysfs_initialized;
 929
 930 struct kobj_type module_ktype = {
 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 */