kernel/params.c

   1 /* Helpers for initial module or kernel cmdline parsing
   2    Copyright (C) 2001 Rusty Russell.
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17 */
  18 #include <linux/kernel.h>
  19 #include <linux/string.h>
  20 #include <linux/errno.h>
  21 #include <linux/module.h>
  22 #include <linux/moduleparam.h>
  23 #include <linux/device.h>
  24 #include <linux/err.h>
  25 #include <linux/slab.h>
  26 #include <linux/ctype.h>
  27
  28 #ifdef CONFIG_SYSFS
  29 /* Protects all built-in parameters, modules use their own param_lock */
  30 static DEFINE_MUTEX(param_lock);
  31
  32 /* Use the module's mutex, or if built-in use the built-in mutex */
  33 #ifdef CONFIG_MODULES
  34 #define KPARAM_MUTEX(mod)       ((mod) ? &(mod)->param_lock : &param_lock)
  35 #else
  36 #define KPARAM_MUTEX(mod)       (&param_lock)
  37 #endif
  38
  39 static inline void check_kparam_locked(struct module *mod)
  40 {
  41         BUG_ON(!mutex_is_locked(KPARAM_MUTEX(mod)));
  42 }
  43 #else
  44 static inline void check_kparam_locked(struct module *mod)
  45 {
  46 }
  47 #endif /* !CONFIG_SYSFS */
  48
  49 /* This just allows us to keep track of which parameters are kmalloced. */
  50 struct kmalloced_param {
  51         struct list_head list;
  52         char val[];
  53 };
  54 static LIST_HEAD(kmalloced_params);
  55 static DEFINE_SPINLOCK(kmalloced_params_lock);
  56
  57 static void *kmalloc_parameter(unsigned int size)
  58 {
  59         struct kmalloced_param *p;
  60
  61         p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
  62         if (!p)
  63                 return NULL;
  64
  65         spin_lock(&kmalloced_params_lock);
  66         list_add(&p->list, &kmalloced_params);
  67         spin_unlock(&kmalloced_params_lock);
  68
  69         return p->val;
  70 }
  71
  72 /* Does nothing if parameter wasn't kmalloced above. */
  73 static void maybe_kfree_parameter(void *param)
  74 {
  75         struct kmalloced_param *p;
  76
  77         spin_lock(&kmalloced_params_lock);
  78         list_for_each_entry(p, &kmalloced_params, list) {
  79                 if (p->val == param) {
  80                         list_del(&p->list);
  81                         kfree(p);
  82                         break;
  83                 }
  84         }
  85         spin_unlock(&kmalloced_params_lock);
  86 }
  87
  88 static char dash2underscore(char c)
  89 {
  90         if (c == '-')
  91                 return '_';
  92         return c;
  93 }
  94
  95 bool parameqn(const char *a, const char *b, size_t n)
  96 {
  97         size_t i;
  98
  99         for (i = 0; i < n; i++) {
 100                 if (dash2underscore(a[i]) != dash2underscore(b[i]))
 101                         return false;
 102         }
 103         return true;
 104 }
 105
 106 bool parameq(const char *a, const char *b)
 107 {
 108         return parameqn(a, b, strlen(a)+1);
 109 }
 110
 111 static void param_check_unsafe(const struct kernel_param *kp)
 112 {
 113         if (kp->flags & KERNEL_PARAM_FL_UNSAFE) {
 114                 pr_warn("Setting dangerous option %s - tainting kernel\n",
 115                         kp->name);
 116                 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 117         }
 118 }
 119
 120 static int parse_one(char *param,
 121                      char *val,
 122                      const char *doing,
 123                      const struct kernel_param *params,
 124                      unsigned num_params,
 125                      s16 min_level,
 126                      s16 max_level,
 127                      void *arg,
 128                      int (*handle_unknown)(char *param, char *val,
 129                                      const char *doing, void *arg))
 130 {
 131         unsigned int i;
 132         int err;
 133
 134         /* Find parameter */
 135         for (i = 0; i < num_params; i++) {
 136                 if (parameq(param, params[i].name)) {
 137                         if (params[i].level < min_level
 138                             || params[i].level > max_level)
 139                                 return 0;
 140                         /* No one handled NULL, so do it here. */
 141                         if (!val &&
 142                             !(params[i].ops->flags & KERNEL_PARAM_OPS_FL_NOARG))
 143                                 return -EINVAL;
 144                         pr_debug("handling %s with %p\n", param,
 145                                 params[i].ops->set);
 146                         kernel_param_lock(params[i].mod);
 147                         param_check_unsafe(&params[i]);
 148                         err = params[i].ops->set(val, &params[i]);
 149                         kernel_param_unlock(params[i].mod);
 150                         return err;
 151                 }
 152         }
 153
 154         if (handle_unknown) {
 155                 pr_debug("doing %s: %s='%s'\n", doing, param, val);
 156                 return handle_unknown(param, val, doing, arg);
 157         }
 158
 159         pr_debug("Unknown argument '%s'\n", param);
 160         return -ENOENT;
 161 }
 162
 163 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 164 char *parse_args(const char *doing,
 165                  char *args,
 166                  const struct kernel_param *params,
 167                  unsigned num,
 168                  s16 min_level,
 169                  s16 max_level,
 170                  void *arg,
 171                  int (*unknown)(char *param, char *val,
 172                                 const char *doing, void *arg))
 173 {
 174         char *param, *val, *err = NULL;
 175
 176         /* Chew leading spaces */
 177         args = skip_spaces(args);
 178
 179         if (*args)
 180                 pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
 181
 182         while (*args) {
 183                 int ret;
 184                 int irq_was_disabled;
 185
 186                 args = next_arg(args, &param, &val);
 187                 /* Stop at -- */
 188                 if (!val && strcmp(param, "--") == 0)
 189                         return err ?: args;
 190                 irq_was_disabled = irqs_disabled();
 191                 ret = parse_one(param, val, doing, params, num,
 192                                 min_level, max_level, arg, unknown);
 193                 if (irq_was_disabled && !irqs_disabled())
 194                         pr_warn("%s: option '%s' enabled irq's!\n",
 195                                 doing, param);
 196
 197                 switch (ret) {
 198                 case 0:
 199                         continue;
 200                 case -ENOENT:
 201                         pr_err("%s: Unknown parameter `%s'\n", doing, param);
 202                         break;
 203                 case -ENOSPC:
 204                         pr_err("%s: `%s' too large for parameter `%s'\n",
 205                                doing, val ?: "", param);
 206                         break;
 207                 default:
 208                         pr_err("%s: `%s' invalid for parameter `%s'\n",
 209                                doing, val ?: "", param);
 210                         break;
 211                 }
 212
 213                 err = ERR_PTR(ret);
 214         }
 215
 216         return err;
 217 }
 218
 219 /* Lazy bastard, eh? */
 220 #define STANDARD_PARAM_DEF(name, type, format, strtolfn)                \
 221         int param_set_##name(const char *val, const struct kernel_param *kp) \
 222         {                                                               \
 223                 return strtolfn(val, 0, (type *)kp->arg);               \
 224         }                                                               \
 225         int param_get_##name(char *buffer, const struct kernel_param *kp) \
 226         {                                                               \
 227                 return scnprintf(buffer, PAGE_SIZE, format,             \
 228                                 *((type *)kp->arg));                    \
 229         }                                                               \
 230         const struct kernel_param_ops param_ops_##name = {                      \
 231                 .set = param_set_##name,                                \
 232                 .get = param_get_##name,                                \
 233         };                                                              \
 234         EXPORT_SYMBOL(param_set_##name);                                \
 235         EXPORT_SYMBOL(param_get_##name);                                \
 236         EXPORT_SYMBOL(param_ops_##name)
 237
 238
 239 STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", kstrtou8);
 240 STANDARD_PARAM_DEF(short, short, "%hi", kstrtos16);
 241 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", kstrtou16);
 242 STANDARD_PARAM_DEF(int, int, "%i", kstrtoint);
 243 STANDARD_PARAM_DEF(uint, unsigned int, "%u", kstrtouint);
 244 STANDARD_PARAM_DEF(long, long, "%li", kstrtol);
 245 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", kstrtoul);
 246 STANDARD_PARAM_DEF(ullong, unsigned long long, "%llu", kstrtoull);
 247
 248 int param_set_charp(const char *val, const struct kernel_param *kp)
 249 {
 250         if (strlen(val) > 1024) {
 251                 pr_err("%s: string parameter too long\n", kp->name);
 252                 return -ENOSPC;
 253         }
 254
 255         maybe_kfree_parameter(*(char **)kp->arg);
 256
 257         /* This is a hack.  We can't kmalloc in early boot, and we
 258          * don't need to; this mangled commandline is preserved. */
 259         if (slab_is_available()) {
 260                 *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
 261                 if (!*(char **)kp->arg)
 262                         return -ENOMEM;
 263                 strcpy(*(char **)kp->arg, val);
 264         } else
 265                 *(const char **)kp->arg = val;
 266
 267         return 0;
 268 }
 269 EXPORT_SYMBOL(param_set_charp);
 270
 271 int param_get_charp(char *buffer, const struct kernel_param *kp)
 272 {
 273         return scnprintf(buffer, PAGE_SIZE, "%s", *((char **)kp->arg));
 274 }
 275 EXPORT_SYMBOL(param_get_charp);
 276
 277 void param_free_charp(void *arg)
 278 {
 279         maybe_kfree_parameter(*((char **)arg));
 280 }
 281 EXPORT_SYMBOL(param_free_charp);
 282
 283 const struct kernel_param_ops param_ops_charp = {
 284         .set = param_set_charp,
 285         .get = param_get_charp,
 286         .free = param_free_charp,
 287 };
 288 EXPORT_SYMBOL(param_ops_charp);
 289
 290 /* Actually could be a bool or an int, for historical reasons. */
 291 int param_set_bool(const char *val, const struct kernel_param *kp)
 292 {
 293         /* No equals means "set"... */
 294         if (!val) val = "1";
 295
 296         /* One of =[yYnN01] */
 297         return strtobool(val, kp->arg);
 298 }
 299 EXPORT_SYMBOL(param_set_bool);
 300
 301 int param_get_bool(char *buffer, const struct kernel_param *kp)
 302 {
 303         /* Y and N chosen as being relatively non-coder friendly */
 304         return sprintf(buffer, "%c", *(bool *)kp->arg ? 'Y' : 'N');
 305 }
 306 EXPORT_SYMBOL(param_get_bool);
 307
 308 const struct kernel_param_ops param_ops_bool = {
 309         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 310         .set = param_set_bool,
 311         .get = param_get_bool,
 312 };
 313 EXPORT_SYMBOL(param_ops_bool);
 314
 315 int param_set_bool_enable_only(const char *val, const struct kernel_param *kp)
 316 {
 317         int err = 0;
 318         bool new_value;
 319         bool orig_value = *(bool *)kp->arg;
 320         struct kernel_param dummy_kp = *kp;
 321
 322         dummy_kp.arg = &new_value;
 323
 324         err = param_set_bool(val, &dummy_kp);
 325         if (err)
 326                 return err;
 327
 328         /* Don't let them unset it once it's set! */
 329         if (!new_value && orig_value)
 330                 return -EROFS;
 331
 332         if (new_value)
 333                 err = param_set_bool(val, kp);
 334
 335         return err;
 336 }
 337 EXPORT_SYMBOL_GPL(param_set_bool_enable_only);
 338
 339 const struct kernel_param_ops param_ops_bool_enable_only = {
 340         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 341         .set = param_set_bool_enable_only,
 342         .get = param_get_bool,
 343 };
 344 EXPORT_SYMBOL_GPL(param_ops_bool_enable_only);
 345
 346 /* This one must be bool. */
 347 int param_set_invbool(const char *val, const struct kernel_param *kp)
 348 {
 349         int ret;
 350         bool boolval;
 351         struct kernel_param dummy;
 352
 353         dummy.arg = &boolval;
 354         ret = param_set_bool(val, &dummy);
 355         if (ret == 0)
 356                 *(bool *)kp->arg = !boolval;
 357         return ret;
 358 }
 359 EXPORT_SYMBOL(param_set_invbool);
 360
 361 int param_get_invbool(char *buffer, const struct kernel_param *kp)
 362 {
 363         return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
 364 }
 365 EXPORT_SYMBOL(param_get_invbool);
 366
 367 const struct kernel_param_ops param_ops_invbool = {
 368         .set = param_set_invbool,
 369         .get = param_get_invbool,
 370 };
 371 EXPORT_SYMBOL(param_ops_invbool);
 372
 373 int param_set_bint(const char *val, const struct kernel_param *kp)
 374 {
 375         /* Match bool exactly, by re-using it. */
 376         struct kernel_param boolkp = *kp;
 377         bool v;
 378         int ret;
 379
 380         boolkp.arg = &v;
 381
 382         ret = param_set_bool(val, &boolkp);
 383         if (ret == 0)
 384                 *(int *)kp->arg = v;
 385         return ret;
 386 }
 387 EXPORT_SYMBOL(param_set_bint);
 388
 389 const struct kernel_param_ops param_ops_bint = {
 390         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 391         .set = param_set_bint,
 392         .get = param_get_int,
 393 };
 394 EXPORT_SYMBOL(param_ops_bint);
 395
 396 /* We break the rule and mangle the string. */
 397 static int param_array(struct module *mod,
 398                        const char *name,
 399                        const char *val,
 400                        unsigned int min, unsigned int max,
 401                        void *elem, int elemsize,
 402                        int (*set)(const char *, const struct kernel_param *kp),
 403                        s16 level,
 404                        unsigned int *num)
 405 {
 406         int ret;
 407         struct kernel_param kp;
 408         char save;
 409
 410         /* Get the name right for errors. */
 411         kp.name = name;
 412         kp.arg = elem;
 413         kp.level = level;
 414
 415         *num = 0;
 416         /* We expect a comma-separated list of values. */
 417         do {
 418                 int len;
 419
 420                 if (*num == max) {
 421                         pr_err("%s: can only take %i arguments\n", name, max);
 422                         return -EINVAL;
 423                 }
 424                 len = strcspn(val, ",");
 425
 426                 /* nul-terminate and parse */
 427                 save = val[len];
 428                 ((char *)val)[len] = '\0';
 429                 check_kparam_locked(mod);
 430                 ret = set(val, &kp);
 431
 432                 if (ret != 0)
 433                         return ret;
 434                 kp.arg += elemsize;
 435                 val += len+1;
 436                 (*num)++;
 437         } while (save == ',');
 438
 439         if (*num < min) {
 440                 pr_err("%s: needs at least %i arguments\n", name, min);
 441                 return -EINVAL;
 442         }
 443         return 0;
 444 }
 445
 446 static int param_array_set(const char *val, const struct kernel_param *kp)
 447 {
 448         const struct kparam_array *arr = kp->arr;
 449         unsigned int temp_num;
 450
 451         return param_array(kp->mod, kp->name, val, 1, arr->max, arr->elem,
 452                            arr->elemsize, arr->ops->set, kp->level,
 453                            arr->num ?: &temp_num);
 454 }
 455
 456 static int param_array_get(char *buffer, const struct kernel_param *kp)
 457 {
 458         int i, off, ret;
 459         const struct kparam_array *arr = kp->arr;
 460         struct kernel_param p = *kp;
 461
 462         for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 463                 if (i)
 464                         buffer[off++] = ',';
 465                 p.arg = arr->elem + arr->elemsize * i;
 466                 check_kparam_locked(p.mod);
 467                 ret = arr->ops->get(buffer + off, &p);
 468                 if (ret < 0)
 469                         return ret;
 470                 off += ret;
 471         }
 472         buffer[off] = '\0';
 473         return off;
 474 }
 475
 476 static void param_array_free(void *arg)
 477 {
 478         unsigned int i;
 479         const struct kparam_array *arr = arg;
 480
 481         if (arr->ops->free)
 482                 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 483                         arr->ops->free(arr->elem + arr->elemsize * i);
 484 }
 485
 486 const struct kernel_param_ops param_array_ops = {
 487         .set = param_array_set,
 488         .get = param_array_get,
 489         .free = param_array_free,
 490 };
 491 EXPORT_SYMBOL(param_array_ops);
 492
 493 int param_set_copystring(const char *val, const struct kernel_param *kp)
 494 {
 495         const struct kparam_string *kps = kp->str;
 496
 497         if (strlen(val)+1 > kps->maxlen) {
 498                 pr_err("%s: string doesn't fit in %u chars.\n",
 499                        kp->name, kps->maxlen-1);
 500                 return -ENOSPC;
 501         }
 502         strcpy(kps->string, val);
 503         return 0;
 504 }
 505 EXPORT_SYMBOL(param_set_copystring);
 506
 507 int param_get_string(char *buffer, const struct kernel_param *kp)
 508 {
 509         const struct kparam_string *kps = kp->str;
 510         return strlcpy(buffer, kps->string, kps->maxlen);
 511 }
 512 EXPORT_SYMBOL(param_get_string);
 513
 514 const struct kernel_param_ops param_ops_string = {
 515         .set = param_set_copystring,
 516         .get = param_get_string,
 517 };
 518 EXPORT_SYMBOL(param_ops_string);
 519
 520 /* sysfs output in /sys/modules/XYZ/parameters/ */
 521 #define to_module_attr(n) container_of(n, struct module_attribute, attr)
 522 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 523
 524 struct param_attribute
 525 {
 526         struct module_attribute mattr;
 527         const struct kernel_param *param;
 528 };
 529
 530 struct module_param_attrs
 531 {
 532         unsigned int num;
 533         struct attribute_group grp;
 534         struct param_attribute attrs[0];
 535 };
 536
 537 #ifdef CONFIG_SYSFS
 538 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 539
 540 static ssize_t param_attr_show(struct module_attribute *mattr,
 541                                struct module_kobject *mk, char *buf)
 542 {
 543         int count;
 544         struct param_attribute *attribute = to_param_attr(mattr);
 545
 546         if (!attribute->param->ops->get)
 547                 return -EPERM;
 548
 549         kernel_param_lock(mk->mod);
 550         count = attribute->param->ops->get(buf, attribute->param);
 551         kernel_param_unlock(mk->mod);
 552         if (count > 0) {
 553                 strcat(buf, "\n");
 554                 ++count;
 555         }
 556         return count;
 557 }
 558
 559 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 560 static ssize_t param_attr_store(struct module_attribute *mattr,
 561                                 struct module_kobject *mk,
 562                                 const char *buf, size_t len)
 563 {
 564         int err;
 565         struct param_attribute *attribute = to_param_attr(mattr);
 566
 567         if (!attribute->param->ops->set)
 568                 return -EPERM;
 569
 570         kernel_param_lock(mk->mod);
 571         param_check_unsafe(attribute->param);
 572         err = attribute->param->ops->set(buf, attribute->param);
 573         kernel_param_unlock(mk->mod);
 574         if (!err)
 575                 return len;
 576         return err;
 577 }
 578 #endif
 579
 580 #ifdef CONFIG_MODULES
 581 #define __modinit
 582 #else
 583 #define __modinit __init
 584 #endif
 585
 586 #ifdef CONFIG_SYSFS
 587 void kernel_param_lock(struct module *mod)
 588 {
 589         mutex_lock(KPARAM_MUTEX(mod));
 590 }
 591
 592 void kernel_param_unlock(struct module *mod)
 593 {
 594         mutex_unlock(KPARAM_MUTEX(mod));
 595 }
 596
 597 EXPORT_SYMBOL(kernel_param_lock);
 598 EXPORT_SYMBOL(kernel_param_unlock);
 599
 600 /*
 601  * add_sysfs_param - add a parameter to sysfs
 602  * @mk: struct module_kobject
 603  * @kparam: the actual parameter definition to add to sysfs
 604  * @name: name of parameter
 605  *
 606  * Create a kobject if for a (per-module) parameter if mp NULL, and
 607  * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 608  * if there's an error.
 609  */
 610 static __modinit int add_sysfs_param(struct module_kobject *mk,
 611                                      const struct kernel_param *kp,
 612                                      const char *name)
 613 {
 614         struct module_param_attrs *new_mp;
 615         struct attribute **new_attrs;
 616         unsigned int i;
 617
 618         /* We don't bother calling this with invisible parameters. */
 619         BUG_ON(!kp->perm);
 620
 621         if (!mk->mp) {
 622                 /* First allocation. */
 623                 mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL);
 624                 if (!mk->mp)
 625                         return -ENOMEM;
 626                 mk->mp->grp.name = "parameters";
 627                 /* NULL-terminated attribute array. */
 628                 mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]),
 629                                             GFP_KERNEL);
 630                 /* Caller will cleanup via free_module_param_attrs */
 631                 if (!mk->mp->grp.attrs)
 632                         return -ENOMEM;
 633         }
 634
 635         /* Enlarge allocations. */
 636         new_mp = krealloc(mk->mp,
 637                           sizeof(*mk->mp) +
 638                           sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1),
 639                           GFP_KERNEL);
 640         if (!new_mp)
 641                 return -ENOMEM;
 642         mk->mp = new_mp;
 643
 644         /* Extra pointer for NULL terminator */
 645         new_attrs = krealloc(mk->mp->grp.attrs,
 646                              sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2),
 647                              GFP_KERNEL);
 648         if (!new_attrs)
 649                 return -ENOMEM;
 650         mk->mp->grp.attrs = new_attrs;
 651
 652         /* Tack new one on the end. */
 653         memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0]));
 654         sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr);
 655         mk->mp->attrs[mk->mp->num].param = kp;
 656         mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show;
 657         /* Do not allow runtime DAC changes to make param writable. */
 658         if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0)
 659                 mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store;
 660         else
 661                 mk->mp->attrs[mk->mp->num].mattr.store = NULL;
 662         mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name;
 663         mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm;
 664         mk->mp->num++;
 665
 666         /* Fix up all the pointers, since krealloc can move us */
 667         for (i = 0; i < mk->mp->num; i++)
 668                 mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr;
 669         mk->mp->grp.attrs[mk->mp->num] = NULL;
 670         return 0;
 671 }
 672
 673 #ifdef CONFIG_MODULES
 674 static void free_module_param_attrs(struct module_kobject *mk)
 675 {
 676         if (mk->mp)
 677                 kfree(mk->mp->grp.attrs);
 678         kfree(mk->mp);
 679         mk->mp = NULL;
 680 }
 681
 682 /*
 683  * module_param_sysfs_setup - setup sysfs support for one module
 684  * @mod: module
 685  * @kparam: module parameters (array)
 686  * @num_params: number of module parameters
 687  *
 688  * Adds sysfs entries for module parameters under
 689  * /sys/module/[mod->name]/parameters/
 690  */
 691 int module_param_sysfs_setup(struct module *mod,
 692                              const struct kernel_param *kparam,
 693                              unsigned int num_params)
 694 {
 695         int i, err;
 696         bool params = false;
 697
 698         for (i = 0; i < num_params; i++) {
 699                 if (kparam[i].perm == 0)
 700                         continue;
 701                 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 702                 if (err) {
 703                         free_module_param_attrs(&mod->mkobj);
 704                         return err;
 705                 }
 706                 params = true;
 707         }
 708
 709         if (!params)
 710                 return 0;
 711
 712         /* Create the param group. */
 713         err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 714         if (err)
 715                 free_module_param_attrs(&mod->mkobj);
 716         return err;
 717 }
 718
 719 /*
 720  * module_param_sysfs_remove - remove sysfs support for one module
 721  * @mod: module
 722  *
 723  * Remove sysfs entries for module parameters and the corresponding
 724  * kobject.
 725  */
 726 void module_param_sysfs_remove(struct module *mod)
 727 {
 728         if (mod->mkobj.mp) {
 729                 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 730                 /* We are positive that no one is using any param
 731                  * attrs at this point.  Deallocate immediately. */
 732                 free_module_param_attrs(&mod->mkobj);
 733         }
 734 }
 735 #endif
 736
 737 void destroy_params(const struct kernel_param *params, unsigned num)
 738 {
 739         unsigned int i;
 740
 741         for (i = 0; i < num; i++)
 742                 if (params[i].ops->free)
 743                         params[i].ops->free(params[i].arg);
 744 }
 745
 746 static struct module_kobject * __init locate_module_kobject(const char *name)
 747 {
 748         struct module_kobject *mk;
 749         struct kobject *kobj;
 750         int err;
 751
 752         kobj = kset_find_obj(module_kset, name);
 753         if (kobj) {
 754                 mk = to_module_kobject(kobj);
 755         } else {
 756                 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 757                 BUG_ON(!mk);
 758
 759                 mk->mod = THIS_MODULE;
 760                 mk->kobj.kset = module_kset;
 761                 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 762                                            "%s", name);
 763 #ifdef CONFIG_MODULES
 764                 if (!err)
 765                         err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
 766 #endif
 767                 if (err) {
 768                         kobject_put(&mk->kobj);
 769                         pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
 770                                 name, err);
 771                         return NULL;
 772                 }
 773
 774                 /* So that we hold reference in both cases. */
 775                 kobject_get(&mk->kobj);
 776         }
 777
 778         return mk;
 779 }
 780
 781 static void __init kernel_add_sysfs_param(const char *name,
 782                                           const struct kernel_param *kparam,
 783                                           unsigned int name_skip)
 784 {
 785         struct module_kobject *mk;
 786         int err;
 787
 788         mk = locate_module_kobject(name);
 789         if (!mk)
 790                 return;
 791
 792         /* We need to remove old parameters before adding more. */
 793         if (mk->mp)
 794                 sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 795
 796         /* These should not fail at boot. */
 797         err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 798         BUG_ON(err);
 799         err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 800         BUG_ON(err);
 801         kobject_uevent(&mk->kobj, KOBJ_ADD);
 802         kobject_put(&mk->kobj);
 803 }
 804
 805 /*
 806  * param_sysfs_builtin - add sysfs parameters for built-in modules
 807  *
 808  * Add module_parameters to sysfs for "modules" built into the kernel.
 809  *
 810  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 811  * "parameter" name is stored behind a dot in kernel_param->name. So,
 812  * extract the "module" name for all built-in kernel_param-eters,
 813  * and for all who have the same, call kernel_add_sysfs_param.
 814  */
 815 static void __init param_sysfs_builtin(void)
 816 {
 817         const struct kernel_param *kp;
 818         unsigned int name_len;
 819         char modname[MODULE_NAME_LEN];
 820
 821         for (kp = __start___param; kp < __stop___param; kp++) {
 822                 char *dot;
 823
 824                 if (kp->perm == 0)
 825                         continue;
 826
 827                 dot = strchr(kp->name, '.');
 828                 if (!dot) {
 829                         /* This happens for core_param() */
 830                         strcpy(modname, "kernel");
 831                         name_len = 0;
 832                 } else {
 833                         name_len = dot - kp->name + 1;
 834                         strlcpy(modname, kp->name, name_len);
 835                 }
 836                 kernel_add_sysfs_param(modname, kp, name_len);
 837         }
 838 }
 839
 840 ssize_t __modver_version_show(struct module_attribute *mattr,
 841                               struct module_kobject *mk, char *buf)
 842 {
 843         struct module_version_attribute *vattr =
 844                 container_of(mattr, struct module_version_attribute, mattr);
 845
 846         return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
 847 }
 848
 849 extern const struct module_version_attribute *__start___modver[];
 850 extern const struct module_version_attribute *__stop___modver[];
 851
 852 static void __init version_sysfs_builtin(void)
 853 {
 854         const struct module_version_attribute **p;
 855         struct module_kobject *mk;
 856         int err;
 857
 858         for (p = __start___modver; p < __stop___modver; p++) {
 859                 const struct module_version_attribute *vattr = *p;
 860
 861                 mk = locate_module_kobject(vattr->module_name);
 862                 if (mk) {
 863                         err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
 864                         WARN_ON_ONCE(err);
 865                         kobject_uevent(&mk->kobj, KOBJ_ADD);
 866                         kobject_put(&mk->kobj);
 867                 }
 868         }
 869 }
 870
 871 /* module-related sysfs stuff */
 872
 873 static ssize_t module_attr_show(struct kobject *kobj,
 874                                 struct attribute *attr,
 875                                 char *buf)
 876 {
 877         struct module_attribute *attribute;
 878         struct module_kobject *mk;
 879         int ret;
 880
 881         attribute = to_module_attr(attr);
 882         mk = to_module_kobject(kobj);
 883
 884         if (!attribute->show)
 885                 return -EIO;
 886
 887         ret = attribute->show(attribute, mk, buf);
 888
 889         return ret;
 890 }
 891
 892 static ssize_t module_attr_store(struct kobject *kobj,
 893                                 struct attribute *attr,
 894                                 const char *buf, size_t len)
 895 {
 896         struct module_attribute *attribute;
 897         struct module_kobject *mk;
 898         int ret;
 899
 900         attribute = to_module_attr(attr);
 901         mk = to_module_kobject(kobj);
 902
 903         if (!attribute->store)
 904                 return -EIO;
 905
 906         ret = attribute->store(attribute, mk, buf, len);
 907
 908         return ret;
 909 }
 910
 911 static const struct sysfs_ops module_sysfs_ops = {
 912         .show = module_attr_show,
 913         .store = module_attr_store,
 914 };
 915
 916 static int uevent_filter(struct kset *kset, struct kobject *kobj)
 917 {
 918         struct kobj_type *ktype = get_ktype(kobj);
 919
 920         if (ktype == &module_ktype)
 921                 return 1;
 922         return 0;
 923 }
 924
 925 static const struct kset_uevent_ops module_uevent_ops = {
 926         .filter = uevent_filter,
 927 };
 928
 929 struct kset *module_kset;
 930 int module_sysfs_initialized;
 931
 932 static void module_kobj_release(struct kobject *kobj)
 933 {
 934         struct module_kobject *mk = to_module_kobject(kobj);
 935         complete(mk->kobj_completion);
 936 }
 937
 938 struct kobj_type module_ktype = {
 939         .release   =    module_kobj_release,
 940         .sysfs_ops =    &module_sysfs_ops,
 941 };
 942
 943 /*
 944  * param_sysfs_init - wrapper for built-in params support
 945  */
 946 static int __init param_sysfs_init(void)
 947 {
 948         module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
 949         if (!module_kset) {
 950                 printk(KERN_WARNING "%s (%d): error creating kset\n",
 951                         __FILE__, __LINE__);
 952                 return -ENOMEM;
 953         }
 954         module_sysfs_initialized = 1;
 955
 956         version_sysfs_builtin();
 957         param_sysfs_builtin();
 958
 959         return 0;
 960 }
 961 subsys_initcall(param_sysfs_init);
 962
 963 #endif /* CONFIG_SYSFS */