kernel/params.c

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