kernel/params.c

   1 /* Helpers for initial module or kernel cmdline parsing
   2    Copyright (C) 2001 Rusty Russell.
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17 */
  18 #include <linux/kernel.h>
  19 #include <linux/string.h>
  20 #include <linux/errno.h>
  21 #include <linux/module.h>
  22 #include <linux/device.h>
  23 #include <linux/err.h>
  24 #include <linux/slab.h>
  25 #include <linux/ctype.h>
  26
  27 /* Protects all parameters, and incidentally kmalloced_param list. */
  28 static DEFINE_MUTEX(param_lock);
  29
  30 /* This just allows us to keep track of which parameters are kmalloced. */
  31 struct kmalloced_param {
  32         struct list_head list;
  33         char val[];
  34 };
  35 static LIST_HEAD(kmalloced_params);
  36
  37 static void *kmalloc_parameter(unsigned int size)
  38 {
  39         struct kmalloced_param *p;
  40
  41         p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
  42         if (!p)
  43                 return NULL;
  44
  45         list_add(&p->list, &kmalloced_params);
  46         return p->val;
  47 }
  48
  49 /* Does nothing if parameter wasn't kmalloced above. */
  50 static void maybe_kfree_parameter(void *param)
  51 {
  52         struct kmalloced_param *p;
  53
  54         list_for_each_entry(p, &kmalloced_params, list) {
  55                 if (p->val == param) {
  56                         list_del(&p->list);
  57                         kfree(p);
  58                         break;
  59                 }
  60         }
  61 }
  62
  63 static char dash2underscore(char c)
  64 {
  65         if (c == '-')
  66                 return '_';
  67         return c;
  68 }
  69
  70 bool parameqn(const char *a, const char *b, size_t n)
  71 {
  72         size_t i;
  73
  74         for (i = 0; i < n; i++) {
  75                 if (dash2underscore(a[i]) != dash2underscore(b[i]))
  76                         return false;
  77         }
  78         return true;
  79 }
  80
  81 bool parameq(const char *a, const char *b)
  82 {
  83         return parameqn(a, b, strlen(a)+1);
  84 }
  85
  86 static int parse_one(char *param,
  87                      char *val,
  88                      const char *doing,
  89                      const struct kernel_param *params,
  90                      unsigned num_params,
  91                      s16 min_level,
  92                      s16 max_level,
  93                      int (*handle_unknown)(char *param, char *val,
  94                                      const char *doing))
  95 {
  96         unsigned int i;
  97         int err;
  98
  99         /* Find parameter */
 100         for (i = 0; i < num_params; i++) {
 101                 if (parameq(param, params[i].name)) {
 102                         if (params[i].level < min_level
 103                             || params[i].level > max_level)
 104                                 return 0;
 105                         /* No one handled NULL, so do it here. */
 106                         if (!val &&
 107                             !(params[i].ops->flags & KERNEL_PARAM_FL_NOARG))
 108                                 return -EINVAL;
 109                         pr_debug("handling %s with %p\n", param,
 110                                 params[i].ops->set);
 111                         mutex_lock(&param_lock);
 112                         err = params[i].ops->set(val, &params[i]);
 113                         mutex_unlock(&param_lock);
 114                         return err;
 115                 }
 116         }
 117
 118         if (handle_unknown) {
 119                 pr_debug("doing %s: %s='%s'\n", doing, param, val);
 120                 return handle_unknown(param, val, doing);
 121         }
 122
 123         pr_debug("Unknown argument '%s'\n", param);
 124         return -ENOENT;
 125 }
 126
 127 /* You can use " around spaces, but can't escape ". */
 128 /* Hyphens and underscores equivalent in parameter names. */
 129 static char *next_arg(char *args, char **param, char **val)
 130 {
 131         unsigned int i, equals = 0;
 132         int in_quote = 0, quoted = 0;
 133         char *next;
 134
 135         if (*args == '"') {
 136                 args++;
 137                 in_quote = 1;
 138                 quoted = 1;
 139         }
 140
 141         for (i = 0; args[i]; i++) {
 142                 if (isspace(args[i]) && !in_quote)
 143                         break;
 144                 if (equals == 0) {
 145                         if (args[i] == '=')
 146                                 equals = i;
 147                 }
 148                 if (args[i] == '"')
 149                         in_quote = !in_quote;
 150         }
 151
 152         *param = args;
 153         if (!equals)
 154                 *val = NULL;
 155         else {
 156                 args[equals] = '\0';
 157                 *val = args + equals + 1;
 158
 159                 /* Don't include quotes in value. */
 160                 if (**val == '"') {
 161                         (*val)++;
 162                         if (args[i-1] == '"')
 163                                 args[i-1] = '\0';
 164                 }
 165                 if (quoted && args[i-1] == '"')
 166                         args[i-1] = '\0';
 167         }
 168
 169         if (args[i]) {
 170                 args[i] = '\0';
 171                 next = args + i + 1;
 172         } else
 173                 next = args + i;
 174
 175         /* Chew up trailing spaces. */
 176         return skip_spaces(next);
 177 }
 178
 179 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 180 int parse_args(const char *doing,
 181                char *args,
 182                const struct kernel_param *params,
 183                unsigned num,
 184                s16 min_level,
 185                s16 max_level,
 186                int (*unknown)(char *param, char *val, const char *doing))
 187 {
 188         char *param, *val;
 189
 190         /* Chew leading spaces */
 191         args = skip_spaces(args);
 192
 193         if (*args)
 194                 pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
 195
 196         while (*args) {
 197                 int ret;
 198                 int irq_was_disabled;
 199
 200                 args = next_arg(args, &param, &val);
 201                 irq_was_disabled = irqs_disabled();
 202                 ret = parse_one(param, val, doing, params, num,
 203                                 min_level, max_level, unknown);
 204                 if (irq_was_disabled && !irqs_disabled())
 205                         pr_warn("%s: option '%s' enabled irq's!\n",
 206                                 doing, param);
 207
 208                 switch (ret) {
 209                 case -ENOENT:
 210                         pr_err("%s: Unknown parameter `%s'\n", doing, param);
 211                         return ret;
 212                 case -ENOSPC:
 213                         pr_err("%s: `%s' too large for parameter `%s'\n",
 214                                doing, val ?: "", param);
 215                         return ret;
 216                 case 0:
 217                         break;
 218                 default:
 219                         pr_err("%s: `%s' invalid for parameter `%s'\n",
 220                                doing, val ?: "", param);
 221                         return ret;
 222                 }
 223         }
 224
 225         /* All parsed OK. */
 226         return 0;
 227 }
 228
 229 /* Lazy bastard, eh? */
 230 #define STANDARD_PARAM_DEF(name, type, format, tmptype, strtolfn)       \
 231         int param_set_##name(const char *val, const struct kernel_param *kp) \
 232         {                                                               \
 233                 tmptype l;                                              \
 234                 int ret;                                                \
 235                                                                         \
 236                 ret = strtolfn(val, 0, &l);                             \
 237                 if (ret < 0 || ((type)l != l))                          \
 238                         return ret < 0 ? ret : -EINVAL;                 \
 239                 *((type *)kp->arg) = l;                                 \
 240                 return 0;                                               \
 241         }                                                               \
 242         int param_get_##name(char *buffer, const struct kernel_param *kp) \
 243         {                                                               \
 244                 return scnprintf(buffer, PAGE_SIZE, format,             \
 245                                 *((type *)kp->arg));                    \
 246         }                                                               \
 247         struct kernel_param_ops param_ops_##name = {                    \
 248                 .set = param_set_##name,                                \
 249                 .get = param_get_##name,                                \
 250         };                                                              \
 251         EXPORT_SYMBOL(param_set_##name);                                \
 252         EXPORT_SYMBOL(param_get_##name);                                \
 253         EXPORT_SYMBOL(param_ops_##name)
 254
 255
 256 STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", unsigned long, kstrtoul);
 257 STANDARD_PARAM_DEF(short, short, "%hi", long, kstrtol);
 258 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, kstrtoul);
 259 STANDARD_PARAM_DEF(int, int, "%i", long, kstrtol);
 260 STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, kstrtoul);
 261 STANDARD_PARAM_DEF(long, long, "%li", long, kstrtol);
 262 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, kstrtoul);
 263
 264 int param_set_charp(const char *val, const struct kernel_param *kp)
 265 {
 266         if (strlen(val) > 1024) {
 267                 pr_err("%s: string parameter too long\n", kp->name);
 268                 return -ENOSPC;
 269         }
 270
 271         maybe_kfree_parameter(*(char **)kp->arg);
 272
 273         /* This is a hack.  We can't kmalloc in early boot, and we
 274          * don't need to; this mangled commandline is preserved. */
 275         if (slab_is_available()) {
 276                 *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
 277                 if (!*(char **)kp->arg)
 278                         return -ENOMEM;
 279                 strcpy(*(char **)kp->arg, val);
 280         } else
 281                 *(const char **)kp->arg = val;
 282
 283         return 0;
 284 }
 285 EXPORT_SYMBOL(param_set_charp);
 286
 287 int param_get_charp(char *buffer, const struct kernel_param *kp)
 288 {
 289         return scnprintf(buffer, PAGE_SIZE, "%s", *((char **)kp->arg));
 290 }
 291 EXPORT_SYMBOL(param_get_charp);
 292
 293 static void param_free_charp(void *arg)
 294 {
 295         maybe_kfree_parameter(*((char **)arg));
 296 }
 297
 298 struct kernel_param_ops param_ops_charp = {
 299         .set = param_set_charp,
 300         .get = param_get_charp,
 301         .free = param_free_charp,
 302 };
 303 EXPORT_SYMBOL(param_ops_charp);
 304
 305 /* Actually could be a bool or an int, for historical reasons. */
 306 int param_set_bool(const char *val, const struct kernel_param *kp)
 307 {
 308         /* No equals means "set"... */
 309         if (!val) val = "1";
 310
 311         /* One of =[yYnN01] */
 312         return strtobool(val, kp->arg);
 313 }
 314 EXPORT_SYMBOL(param_set_bool);
 315
 316 int param_get_bool(char *buffer, const struct kernel_param *kp)
 317 {
 318         /* Y and N chosen as being relatively non-coder friendly */
 319         return sprintf(buffer, "%c", *(bool *)kp->arg ? 'Y' : 'N');
 320 }
 321 EXPORT_SYMBOL(param_get_bool);
 322
 323 struct kernel_param_ops param_ops_bool = {
 324         .flags = KERNEL_PARAM_FL_NOARG,
 325         .set = param_set_bool,
 326         .get = param_get_bool,
 327 };
 328 EXPORT_SYMBOL(param_ops_bool);
 329
 330 /* This one must be bool. */
 331 int param_set_invbool(const char *val, const struct kernel_param *kp)
 332 {
 333         int ret;
 334         bool boolval;
 335         struct kernel_param dummy;
 336
 337         dummy.arg = &boolval;
 338         ret = param_set_bool(val, &dummy);
 339         if (ret == 0)
 340                 *(bool *)kp->arg = !boolval;
 341         return ret;
 342 }
 343 EXPORT_SYMBOL(param_set_invbool);
 344
 345 int param_get_invbool(char *buffer, const struct kernel_param *kp)
 346 {
 347         return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
 348 }
 349 EXPORT_SYMBOL(param_get_invbool);
 350
 351 struct kernel_param_ops param_ops_invbool = {
 352         .set = param_set_invbool,
 353         .get = param_get_invbool,
 354 };
 355 EXPORT_SYMBOL(param_ops_invbool);
 356
 357 int param_set_bint(const char *val, const struct kernel_param *kp)
 358 {
 359         struct kernel_param boolkp;
 360         bool v;
 361         int ret;
 362
 363         /* Match bool exactly, by re-using it. */
 364         boolkp = *kp;
 365         boolkp.arg = &v;
 366
 367         ret = param_set_bool(val, &boolkp);
 368         if (ret == 0)
 369                 *(int *)kp->arg = v;
 370         return ret;
 371 }
 372 EXPORT_SYMBOL(param_set_bint);
 373
 374 struct kernel_param_ops param_ops_bint = {
 375         .flags = KERNEL_PARAM_FL_NOARG,
 376         .set = param_set_bint,
 377         .get = param_get_int,
 378 };
 379 EXPORT_SYMBOL(param_ops_bint);
 380
 381 /* We break the rule and mangle the string. */
 382 static int param_array(const char *name,
 383                        const char *val,
 384                        unsigned int min, unsigned int max,
 385                        void *elem, int elemsize,
 386                        int (*set)(const char *, const struct kernel_param *kp),
 387                        s16 level,
 388                        unsigned int *num)
 389 {
 390         int ret;
 391         struct kernel_param kp;
 392         char save;
 393
 394         /* Get the name right for errors. */
 395         kp.name = name;
 396         kp.arg = elem;
 397         kp.level = level;
 398
 399         *num = 0;
 400         /* We expect a comma-separated list of values. */
 401         do {
 402                 int len;
 403
 404                 if (*num == max) {
 405                         pr_err("%s: can only take %i arguments\n", name, max);
 406                         return -EINVAL;
 407                 }
 408                 len = strcspn(val, ",");
 409
 410                 /* nul-terminate and parse */
 411                 save = val[len];
 412                 ((char *)val)[len] = '\0';
 413                 BUG_ON(!mutex_is_locked(&param_lock));
 414                 ret = set(val, &kp);
 415
 416                 if (ret != 0)
 417                         return ret;
 418                 kp.arg += elemsize;
 419                 val += len+1;
 420                 (*num)++;
 421         } while (save == ',');
 422
 423         if (*num < min) {
 424                 pr_err("%s: needs at least %i arguments\n", name, min);
 425                 return -EINVAL;
 426         }
 427         return 0;
 428 }
 429
 430 static int param_array_set(const char *val, const struct kernel_param *kp)
 431 {
 432         const struct kparam_array *arr = kp->arr;
 433         unsigned int temp_num;
 434
 435         return param_array(kp->name, val, 1, arr->max, arr->elem,
 436                            arr->elemsize, arr->ops->set, kp->level,
 437                            arr->num ?: &temp_num);
 438 }
 439
 440 static int param_array_get(char *buffer, const struct kernel_param *kp)
 441 {
 442         int i, off, ret;
 443         const struct kparam_array *arr = kp->arr;
 444         struct kernel_param p;
 445
 446         p = *kp;
 447         for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 448                 if (i)
 449                         buffer[off++] = ',';
 450                 p.arg = arr->elem + arr->elemsize * i;
 451                 BUG_ON(!mutex_is_locked(&param_lock));
 452                 ret = arr->ops->get(buffer + off, &p);
 453                 if (ret < 0)
 454                         return ret;
 455                 off += ret;
 456         }
 457         buffer[off] = '\0';
 458         return off;
 459 }
 460
 461 static void param_array_free(void *arg)
 462 {
 463         unsigned int i;
 464         const struct kparam_array *arr = arg;
 465
 466         if (arr->ops->free)
 467                 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 468                         arr->ops->free(arr->elem + arr->elemsize * i);
 469 }
 470
 471 struct kernel_param_ops param_array_ops = {
 472         .set = param_array_set,
 473         .get = param_array_get,
 474         .free = param_array_free,
 475 };
 476 EXPORT_SYMBOL(param_array_ops);
 477
 478 int param_set_copystring(const char *val, const struct kernel_param *kp)
 479 {
 480         const struct kparam_string *kps = kp->str;
 481
 482         if (strlen(val)+1 > kps->maxlen) {
 483                 pr_err("%s: string doesn't fit in %u chars.\n",
 484                        kp->name, kps->maxlen-1);
 485                 return -ENOSPC;
 486         }
 487         strcpy(kps->string, val);
 488         return 0;
 489 }
 490 EXPORT_SYMBOL(param_set_copystring);
 491
 492 int param_get_string(char *buffer, const struct kernel_param *kp)
 493 {
 494         const struct kparam_string *kps = kp->str;
 495         return strlcpy(buffer, kps->string, kps->maxlen);
 496 }
 497 EXPORT_SYMBOL(param_get_string);
 498
 499 struct kernel_param_ops param_ops_string = {
 500         .set = param_set_copystring,
 501         .get = param_get_string,
 502 };
 503 EXPORT_SYMBOL(param_ops_string);
 504
 505 /* sysfs output in /sys/modules/XYZ/parameters/ */
 506 #define to_module_attr(n) container_of(n, struct module_attribute, attr)
 507 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 508
 509 extern struct kernel_param __start___param[], __stop___param[];
 510
 511 struct param_attribute
 512 {
 513         struct module_attribute mattr;
 514         const struct kernel_param *param;
 515 };
 516
 517 struct module_param_attrs
 518 {
 519         unsigned int num;
 520         struct attribute_group grp;
 521         struct param_attribute attrs[0];
 522 };
 523
 524 #ifdef CONFIG_SYSFS
 525 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 526
 527 static ssize_t param_attr_show(struct module_attribute *mattr,
 528                                struct module_kobject *mk, char *buf)
 529 {
 530         int count;
 531         struct param_attribute *attribute = to_param_attr(mattr);
 532
 533         if (!attribute->param->ops->get)
 534                 return -EPERM;
 535
 536         mutex_lock(&param_lock);
 537         count = attribute->param->ops->get(buf, attribute->param);
 538         mutex_unlock(&param_lock);
 539         if (count > 0) {
 540                 strcat(buf, "\n");
 541                 ++count;
 542         }
 543         return count;
 544 }
 545
 546 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 547 static ssize_t param_attr_store(struct module_attribute *mattr,
 548                                 struct module_kobject *km,
 549                                 const char *buf, size_t len)
 550 {
 551         int err;
 552         struct param_attribute *attribute = to_param_attr(mattr);
 553
 554         if (!attribute->param->ops->set)
 555                 return -EPERM;
 556
 557         mutex_lock(&param_lock);
 558         err = attribute->param->ops->set(buf, attribute->param);
 559         mutex_unlock(&param_lock);
 560         if (!err)
 561                 return len;
 562         return err;
 563 }
 564 #endif
 565
 566 #ifdef CONFIG_MODULES
 567 #define __modinit
 568 #else
 569 #define __modinit __init
 570 #endif
 571
 572 #ifdef CONFIG_SYSFS
 573 void __kernel_param_lock(void)
 574 {
 575         mutex_lock(&param_lock);
 576 }
 577 EXPORT_SYMBOL(__kernel_param_lock);
 578
 579 void __kernel_param_unlock(void)
 580 {
 581         mutex_unlock(&param_lock);
 582 }
 583 EXPORT_SYMBOL(__kernel_param_unlock);
 584
 585 /*
 586  * add_sysfs_param - add a parameter to sysfs
 587  * @mk: struct module_kobject
 588  * @kparam: the actual parameter definition to add to sysfs
 589  * @name: name of parameter
 590  *
 591  * Create a kobject if for a (per-module) parameter if mp NULL, and
 592  * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 593  * if there's an error.
 594  */
 595 static __modinit int add_sysfs_param(struct module_kobject *mk,
 596                                      const struct kernel_param *kp,
 597                                      const char *name)
 598 {
 599         struct module_param_attrs *new;
 600         struct attribute **attrs;
 601         int err, num;
 602
 603         /* We don't bother calling this with invisible parameters. */
 604         BUG_ON(!kp->perm);
 605
 606         if (!mk->mp) {
 607                 num = 0;
 608                 attrs = NULL;
 609         } else {
 610                 num = mk->mp->num;
 611                 attrs = mk->mp->grp.attrs;
 612         }
 613
 614         /* Enlarge. */
 615         new = krealloc(mk->mp,
 616                        sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
 617                        GFP_KERNEL);
 618         if (!new) {
 619                 kfree(attrs);
 620                 err = -ENOMEM;
 621                 goto fail;
 622         }
 623         /* Despite looking like the typical realloc() bug, this is safe.
 624          * We *want* the old 'attrs' to be freed either way, and we'll store
 625          * the new one in the success case. */
 626         attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
 627         if (!attrs) {
 628                 err = -ENOMEM;
 629                 goto fail_free_new;
 630         }
 631
 632         /* Sysfs wants everything zeroed. */
 633         memset(new, 0, sizeof(*new));
 634         memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
 635         memset(&attrs[num], 0, sizeof(attrs[num]));
 636         new->grp.name = "parameters";
 637         new->grp.attrs = attrs;
 638
 639         /* Tack new one on the end. */
 640         sysfs_attr_init(&new->attrs[num].mattr.attr);
 641         new->attrs[num].param = kp;
 642         new->attrs[num].mattr.show = param_attr_show;
 643         new->attrs[num].mattr.store = param_attr_store;
 644         new->attrs[num].mattr.attr.name = (char *)name;
 645         new->attrs[num].mattr.attr.mode = kp->perm;
 646         new->num = num+1;
 647
 648         /* Fix up all the pointers, since krealloc can move us */
 649         for (num = 0; num < new->num; num++)
 650                 new->grp.attrs[num] = &new->attrs[num].mattr.attr;
 651         new->grp.attrs[num] = NULL;
 652
 653         mk->mp = new;
 654         return 0;
 655
 656 fail_free_new:
 657         kfree(new);
 658 fail:
 659         mk->mp = NULL;
 660         return err;
 661 }
 662
 663 #ifdef CONFIG_MODULES
 664 static void free_module_param_attrs(struct module_kobject *mk)
 665 {
 666         kfree(mk->mp->grp.attrs);
 667         kfree(mk->mp);
 668         mk->mp = NULL;
 669 }
 670
 671 /*
 672  * module_param_sysfs_setup - setup sysfs support for one module
 673  * @mod: module
 674  * @kparam: module parameters (array)
 675  * @num_params: number of module parameters
 676  *
 677  * Adds sysfs entries for module parameters under
 678  * /sys/module/[mod->name]/parameters/
 679  */
 680 int module_param_sysfs_setup(struct module *mod,
 681                              const struct kernel_param *kparam,
 682                              unsigned int num_params)
 683 {
 684         int i, err;
 685         bool params = false;
 686
 687         for (i = 0; i < num_params; i++) {
 688                 if (kparam[i].perm == 0)
 689                         continue;
 690                 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 691                 if (err)
 692                         return err;
 693                 params = true;
 694         }
 695
 696         if (!params)
 697                 return 0;
 698
 699         /* Create the param group. */
 700         err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 701         if (err)
 702                 free_module_param_attrs(&mod->mkobj);
 703         return err;
 704 }
 705
 706 /*
 707  * module_param_sysfs_remove - remove sysfs support for one module
 708  * @mod: module
 709  *
 710  * Remove sysfs entries for module parameters and the corresponding
 711  * kobject.
 712  */
 713 void module_param_sysfs_remove(struct module *mod)
 714 {
 715         if (mod->mkobj.mp) {
 716                 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 717                 /* We are positive that no one is using any param
 718                  * attrs at this point.  Deallocate immediately. */
 719                 free_module_param_attrs(&mod->mkobj);
 720         }
 721 }
 722 #endif
 723
 724 void destroy_params(const struct kernel_param *params, unsigned num)
 725 {
 726         unsigned int i;
 727
 728         for (i = 0; i < num; i++)
 729                 if (params[i].ops->free)
 730                         params[i].ops->free(params[i].arg);
 731 }
 732
 733 static struct module_kobject * __init locate_module_kobject(const char *name)
 734 {
 735         struct module_kobject *mk;
 736         struct kobject *kobj;
 737         int err;
 738
 739         kobj = kset_find_obj(module_kset, name);
 740         if (kobj) {
 741                 mk = to_module_kobject(kobj);
 742         } else {
 743                 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 744                 BUG_ON(!mk);
 745
 746                 mk->mod = THIS_MODULE;
 747                 mk->kobj.kset = module_kset;
 748                 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 749                                            "%s", name);
 750 #ifdef CONFIG_MODULES
 751                 if (!err)
 752                         err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
 753 #endif
 754                 if (err) {
 755                         kobject_put(&mk->kobj);
 756                         pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
 757                                 name, err);
 758                         return NULL;
 759                 }
 760
 761                 /* So that we hold reference in both cases. */
 762                 kobject_get(&mk->kobj);
 763         }
 764
 765         return mk;
 766 }
 767
 768 static void __init kernel_add_sysfs_param(const char *name,
 769                                           struct kernel_param *kparam,
 770                                           unsigned int name_skip)
 771 {
 772         struct module_kobject *mk;
 773         int err;
 774
 775         mk = locate_module_kobject(name);
 776         if (!mk)
 777                 return;
 778
 779         /* We need to remove old parameters before adding more. */
 780         if (mk->mp)
 781                 sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 782
 783         /* These should not fail at boot. */
 784         err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 785         BUG_ON(err);
 786         err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 787         BUG_ON(err);
 788         kobject_uevent(&mk->kobj, KOBJ_ADD);
 789         kobject_put(&mk->kobj);
 790 }
 791
 792 /*
 793  * param_sysfs_builtin - add sysfs parameters for built-in modules
 794  *
 795  * Add module_parameters to sysfs for "modules" built into the kernel.
 796  *
 797  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 798  * "parameter" name is stored behind a dot in kernel_param->name. So,
 799  * extract the "module" name for all built-in kernel_param-eters,
 800  * and for all who have the same, call kernel_add_sysfs_param.
 801  */
 802 static void __init param_sysfs_builtin(void)
 803 {
 804         struct kernel_param *kp;
 805         unsigned int name_len;
 806         char modname[MODULE_NAME_LEN];
 807
 808         for (kp = __start___param; kp < __stop___param; kp++) {
 809                 char *dot;
 810
 811                 if (kp->perm == 0)
 812                         continue;
 813
 814                 dot = strchr(kp->name, '.');
 815                 if (!dot) {
 816                         /* This happens for core_param() */
 817                         strcpy(modname, "kernel");
 818                         name_len = 0;
 819                 } else {
 820                         name_len = dot - kp->name + 1;
 821                         strlcpy(modname, kp->name, name_len);
 822                 }
 823                 kernel_add_sysfs_param(modname, kp, name_len);
 824         }
 825 }
 826
 827 ssize_t __modver_version_show(struct module_attribute *mattr,
 828                               struct module_kobject *mk, char *buf)
 829 {
 830         struct module_version_attribute *vattr =
 831                 container_of(mattr, struct module_version_attribute, mattr);
 832
 833         return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
 834 }
 835
 836 extern const struct module_version_attribute *__start___modver[];
 837 extern const struct module_version_attribute *__stop___modver[];
 838
 839 static void __init version_sysfs_builtin(void)
 840 {
 841         const struct module_version_attribute **p;
 842         struct module_kobject *mk;
 843         int err;
 844
 845         for (p = __start___modver; p < __stop___modver; p++) {
 846                 const struct module_version_attribute *vattr = *p;
 847
 848                 mk = locate_module_kobject(vattr->module_name);
 849                 if (mk) {
 850                         err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
 851                         kobject_uevent(&mk->kobj, KOBJ_ADD);
 852                         kobject_put(&mk->kobj);
 853                 }
 854         }
 855 }
 856
 857 /* module-related sysfs stuff */
 858
 859 static ssize_t module_attr_show(struct kobject *kobj,
 860                                 struct attribute *attr,
 861                                 char *buf)
 862 {
 863         struct module_attribute *attribute;
 864         struct module_kobject *mk;
 865         int ret;
 866
 867         attribute = to_module_attr(attr);
 868         mk = to_module_kobject(kobj);
 869
 870         if (!attribute->show)
 871                 return -EIO;
 872
 873         ret = attribute->show(attribute, mk, buf);
 874
 875         return ret;
 876 }
 877
 878 static ssize_t module_attr_store(struct kobject *kobj,
 879                                 struct attribute *attr,
 880                                 const char *buf, size_t len)
 881 {
 882         struct module_attribute *attribute;
 883         struct module_kobject *mk;
 884         int ret;
 885
 886         attribute = to_module_attr(attr);
 887         mk = to_module_kobject(kobj);
 888
 889         if (!attribute->store)
 890                 return -EIO;
 891
 892         ret = attribute->store(attribute, mk, buf, len);
 893
 894         return ret;
 895 }
 896
 897 static const struct sysfs_ops module_sysfs_ops = {
 898         .show = module_attr_show,
 899         .store = module_attr_store,
 900 };
 901
 902 static int uevent_filter(struct kset *kset, struct kobject *kobj)
 903 {
 904         struct kobj_type *ktype = get_ktype(kobj);
 905
 906         if (ktype == &module_ktype)
 907                 return 1;
 908         return 0;
 909 }
 910
 911 static const struct kset_uevent_ops module_uevent_ops = {
 912         .filter = uevent_filter,
 913 };
 914
 915 struct kset *module_kset;
 916 int module_sysfs_initialized;
 917
 918 static void module_kobj_release(struct kobject *kobj)
 919 {
 920         struct module_kobject *mk = to_module_kobject(kobj);
 921         complete(mk->kobj_completion);
 922 }
 923
 924 struct kobj_type module_ktype = {
 925         .release   =    module_kobj_release,
 926         .sysfs_ops =    &module_sysfs_ops,
 927 };
 928
 929 /*
 930  * param_sysfs_init - wrapper for built-in params support
 931  */
 932 static int __init param_sysfs_init(void)
 933 {
 934         module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
 935         if (!module_kset) {
 936                 printk(KERN_WARNING "%s (%d): error creating kset\n",
 937                         __FILE__, __LINE__);
 938                 return -ENOMEM;
 939         }
 940         module_sysfs_initialized = 1;
 941
 942         version_sysfs_builtin();
 943         param_sysfs_builtin();
 944
 945         return 0;
 946 }
 947 subsys_initcall(param_sysfs_init);
 948
 949 #endif /* CONFIG_SYSFS */