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 char *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                 /* Stop at -- */
 202                 if (!val && strcmp(param, "--") == 0)
 203                         return args;
 204                 irq_was_disabled = irqs_disabled();
 205                 ret = parse_one(param, val, doing, params, num,
 206                                 min_level, max_level, unknown);
 207                 if (irq_was_disabled && !irqs_disabled())
 208                         pr_warn("%s: option '%s' enabled irq's!\n",
 209                                 doing, param);
 210
 211                 switch (ret) {
 212                 case -ENOENT:
 213                         pr_err("%s: Unknown parameter `%s'\n", doing, param);
 214                         return ERR_PTR(ret);
 215                 case -ENOSPC:
 216                         pr_err("%s: `%s' too large for parameter `%s'\n",
 217                                doing, val ?: "", param);
 218                         return ERR_PTR(ret);
 219                 case 0:
 220                         break;
 221                 default:
 222                         pr_err("%s: `%s' invalid for parameter `%s'\n",
 223                                doing, val ?: "", param);
 224                         return ERR_PTR(ret);
 225                 }
 226         }
 227
 228         /* All parsed OK. */
 229         return NULL;
 230 }
 231
 232 /* Lazy bastard, eh? */
 233 #define STANDARD_PARAM_DEF(name, type, format, strtolfn)                \
 234         int param_set_##name(const char *val, const struct kernel_param *kp) \
 235         {                                                               \
 236                 return strtolfn(val, 0, (type *)kp->arg);               \
 237         }                                                               \
 238         int param_get_##name(char *buffer, const struct kernel_param *kp) \
 239         {                                                               \
 240                 return scnprintf(buffer, PAGE_SIZE, format,             \
 241                                 *((type *)kp->arg));                    \
 242         }                                                               \
 243         struct kernel_param_ops param_ops_##name = {                    \
 244                 .set = param_set_##name,                                \
 245                 .get = param_get_##name,                                \
 246         };                                                              \
 247         EXPORT_SYMBOL(param_set_##name);                                \
 248         EXPORT_SYMBOL(param_get_##name);                                \
 249         EXPORT_SYMBOL(param_ops_##name)
 250
 251
 252 STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", kstrtou8);
 253 STANDARD_PARAM_DEF(short, short, "%hi", kstrtos16);
 254 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", kstrtou16);
 255 STANDARD_PARAM_DEF(int, int, "%i", kstrtoint);
 256 STANDARD_PARAM_DEF(uint, unsigned int, "%u", kstrtouint);
 257 STANDARD_PARAM_DEF(long, long, "%li", kstrtol);
 258 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", kstrtoul);
 259
 260 int param_set_charp(const char *val, const struct kernel_param *kp)
 261 {
 262         if (strlen(val) > 1024) {
 263                 pr_err("%s: string parameter too long\n", kp->name);
 264                 return -ENOSPC;
 265         }
 266
 267         maybe_kfree_parameter(*(char **)kp->arg);
 268
 269         /* This is a hack.  We can't kmalloc in early boot, and we
 270          * don't need to; this mangled commandline is preserved. */
 271         if (slab_is_available()) {
 272                 *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
 273                 if (!*(char **)kp->arg)
 274                         return -ENOMEM;
 275                 strcpy(*(char **)kp->arg, val);
 276         } else
 277                 *(const char **)kp->arg = val;
 278
 279         return 0;
 280 }
 281 EXPORT_SYMBOL(param_set_charp);
 282
 283 int param_get_charp(char *buffer, const struct kernel_param *kp)
 284 {
 285         return scnprintf(buffer, PAGE_SIZE, "%s", *((char **)kp->arg));
 286 }
 287 EXPORT_SYMBOL(param_get_charp);
 288
 289 static void param_free_charp(void *arg)
 290 {
 291         maybe_kfree_parameter(*((char **)arg));
 292 }
 293
 294 struct kernel_param_ops param_ops_charp = {
 295         .set = param_set_charp,
 296         .get = param_get_charp,
 297         .free = param_free_charp,
 298 };
 299 EXPORT_SYMBOL(param_ops_charp);
 300
 301 /* Actually could be a bool or an int, for historical reasons. */
 302 int param_set_bool(const char *val, const struct kernel_param *kp)
 303 {
 304         /* No equals means "set"... */
 305         if (!val) val = "1";
 306
 307         /* One of =[yYnN01] */
 308         return strtobool(val, kp->arg);
 309 }
 310 EXPORT_SYMBOL(param_set_bool);
 311
 312 int param_get_bool(char *buffer, const struct kernel_param *kp)
 313 {
 314         /* Y and N chosen as being relatively non-coder friendly */
 315         return sprintf(buffer, "%c", *(bool *)kp->arg ? 'Y' : 'N');
 316 }
 317 EXPORT_SYMBOL(param_get_bool);
 318
 319 struct kernel_param_ops param_ops_bool = {
 320         .flags = KERNEL_PARAM_FL_NOARG,
 321         .set = param_set_bool,
 322         .get = param_get_bool,
 323 };
 324 EXPORT_SYMBOL(param_ops_bool);
 325
 326 /* This one must be bool. */
 327 int param_set_invbool(const char *val, const struct kernel_param *kp)
 328 {
 329         int ret;
 330         bool boolval;
 331         struct kernel_param dummy;
 332
 333         dummy.arg = &boolval;
 334         ret = param_set_bool(val, &dummy);
 335         if (ret == 0)
 336                 *(bool *)kp->arg = !boolval;
 337         return ret;
 338 }
 339 EXPORT_SYMBOL(param_set_invbool);
 340
 341 int param_get_invbool(char *buffer, const struct kernel_param *kp)
 342 {
 343         return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
 344 }
 345 EXPORT_SYMBOL(param_get_invbool);
 346
 347 struct kernel_param_ops param_ops_invbool = {
 348         .set = param_set_invbool,
 349         .get = param_get_invbool,
 350 };
 351 EXPORT_SYMBOL(param_ops_invbool);
 352
 353 int param_set_bint(const char *val, const struct kernel_param *kp)
 354 {
 355         struct kernel_param boolkp;
 356         bool v;
 357         int ret;
 358
 359         /* Match bool exactly, by re-using it. */
 360         boolkp = *kp;
 361         boolkp.arg = &v;
 362
 363         ret = param_set_bool(val, &boolkp);
 364         if (ret == 0)
 365                 *(int *)kp->arg = v;
 366         return ret;
 367 }
 368 EXPORT_SYMBOL(param_set_bint);
 369
 370 struct kernel_param_ops param_ops_bint = {
 371         .flags = KERNEL_PARAM_FL_NOARG,
 372         .set = param_set_bint,
 373         .get = param_get_int,
 374 };
 375 EXPORT_SYMBOL(param_ops_bint);
 376
 377 /* We break the rule and mangle the string. */
 378 static int param_array(const char *name,
 379                        const char *val,
 380                        unsigned int min, unsigned int max,
 381                        void *elem, int elemsize,
 382                        int (*set)(const char *, const struct kernel_param *kp),
 383                        s16 level,
 384                        unsigned int *num)
 385 {
 386         int ret;
 387         struct kernel_param kp;
 388         char save;
 389
 390         /* Get the name right for errors. */
 391         kp.name = name;
 392         kp.arg = elem;
 393         kp.level = level;
 394
 395         *num = 0;
 396         /* We expect a comma-separated list of values. */
 397         do {
 398                 int len;
 399
 400                 if (*num == max) {
 401                         pr_err("%s: can only take %i arguments\n", name, max);
 402                         return -EINVAL;
 403                 }
 404                 len = strcspn(val, ",");
 405
 406                 /* nul-terminate and parse */
 407                 save = val[len];
 408                 ((char *)val)[len] = '\0';
 409                 BUG_ON(!mutex_is_locked(&param_lock));
 410                 ret = set(val, &kp);
 411
 412                 if (ret != 0)
 413                         return ret;
 414                 kp.arg += elemsize;
 415                 val += len+1;
 416                 (*num)++;
 417         } while (save == ',');
 418
 419         if (*num < min) {
 420                 pr_err("%s: needs at least %i arguments\n", name, min);
 421                 return -EINVAL;
 422         }
 423         return 0;
 424 }
 425
 426 static int param_array_set(const char *val, const struct kernel_param *kp)
 427 {
 428         const struct kparam_array *arr = kp->arr;
 429         unsigned int temp_num;
 430
 431         return param_array(kp->name, val, 1, arr->max, arr->elem,
 432                            arr->elemsize, arr->ops->set, kp->level,
 433                            arr->num ?: &temp_num);
 434 }
 435
 436 static int param_array_get(char *buffer, const struct kernel_param *kp)
 437 {
 438         int i, off, ret;
 439         const struct kparam_array *arr = kp->arr;
 440         struct kernel_param p;
 441
 442         p = *kp;
 443         for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 444                 if (i)
 445                         buffer[off++] = ',';
 446                 p.arg = arr->elem + arr->elemsize * i;
 447                 BUG_ON(!mutex_is_locked(&param_lock));
 448                 ret = arr->ops->get(buffer + off, &p);
 449                 if (ret < 0)
 450                         return ret;
 451                 off += ret;
 452         }
 453         buffer[off] = '\0';
 454         return off;
 455 }
 456
 457 static void param_array_free(void *arg)
 458 {
 459         unsigned int i;
 460         const struct kparam_array *arr = arg;
 461
 462         if (arr->ops->free)
 463                 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 464                         arr->ops->free(arr->elem + arr->elemsize * i);
 465 }
 466
 467 struct kernel_param_ops param_array_ops = {
 468         .set = param_array_set,
 469         .get = param_array_get,
 470         .free = param_array_free,
 471 };
 472 EXPORT_SYMBOL(param_array_ops);
 473
 474 int param_set_copystring(const char *val, const struct kernel_param *kp)
 475 {
 476         const struct kparam_string *kps = kp->str;
 477
 478         if (strlen(val)+1 > kps->maxlen) {
 479                 pr_err("%s: string doesn't fit in %u chars.\n",
 480                        kp->name, kps->maxlen-1);
 481                 return -ENOSPC;
 482         }
 483         strcpy(kps->string, val);
 484         return 0;
 485 }
 486 EXPORT_SYMBOL(param_set_copystring);
 487
 488 int param_get_string(char *buffer, const struct kernel_param *kp)
 489 {
 490         const struct kparam_string *kps = kp->str;
 491         return strlcpy(buffer, kps->string, kps->maxlen);
 492 }
 493 EXPORT_SYMBOL(param_get_string);
 494
 495 struct kernel_param_ops param_ops_string = {
 496         .set = param_set_copystring,
 497         .get = param_get_string,
 498 };
 499 EXPORT_SYMBOL(param_ops_string);
 500
 501 /* sysfs output in /sys/modules/XYZ/parameters/ */
 502 #define to_module_attr(n) container_of(n, struct module_attribute, attr)
 503 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 504
 505 extern struct kernel_param __start___param[], __stop___param[];
 506
 507 struct param_attribute
 508 {
 509         struct module_attribute mattr;
 510         const struct kernel_param *param;
 511 };
 512
 513 struct module_param_attrs
 514 {
 515         unsigned int num;
 516         struct attribute_group grp;
 517         struct param_attribute attrs[0];
 518 };
 519
 520 #ifdef CONFIG_SYSFS
 521 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 522
 523 static ssize_t param_attr_show(struct module_attribute *mattr,
 524                                struct module_kobject *mk, char *buf)
 525 {
 526         int count;
 527         struct param_attribute *attribute = to_param_attr(mattr);
 528
 529         if (!attribute->param->ops->get)
 530                 return -EPERM;
 531
 532         mutex_lock(&param_lock);
 533         count = attribute->param->ops->get(buf, attribute->param);
 534         mutex_unlock(&param_lock);
 535         if (count > 0) {
 536                 strcat(buf, "\n");
 537                 ++count;
 538         }
 539         return count;
 540 }
 541
 542 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 543 static ssize_t param_attr_store(struct module_attribute *mattr,
 544                                 struct module_kobject *km,
 545                                 const char *buf, size_t len)
 546 {
 547         int err;
 548         struct param_attribute *attribute = to_param_attr(mattr);
 549
 550         if (!attribute->param->ops->set)
 551                 return -EPERM;
 552
 553         mutex_lock(&param_lock);
 554         err = attribute->param->ops->set(buf, attribute->param);
 555         mutex_unlock(&param_lock);
 556         if (!err)
 557                 return len;
 558         return err;
 559 }
 560 #endif
 561
 562 #ifdef CONFIG_MODULES
 563 #define __modinit
 564 #else
 565 #define __modinit __init
 566 #endif
 567
 568 #ifdef CONFIG_SYSFS
 569 void __kernel_param_lock(void)
 570 {
 571         mutex_lock(&param_lock);
 572 }
 573 EXPORT_SYMBOL(__kernel_param_lock);
 574
 575 void __kernel_param_unlock(void)
 576 {
 577         mutex_unlock(&param_lock);
 578 }
 579 EXPORT_SYMBOL(__kernel_param_unlock);
 580
 581 /*
 582  * add_sysfs_param - add a parameter to sysfs
 583  * @mk: struct module_kobject
 584  * @kparam: the actual parameter definition to add to sysfs
 585  * @name: name of parameter
 586  *
 587  * Create a kobject if for a (per-module) parameter if mp NULL, and
 588  * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 589  * if there's an error.
 590  */
 591 static __modinit int add_sysfs_param(struct module_kobject *mk,
 592                                      const struct kernel_param *kp,
 593                                      const char *name)
 594 {
 595         struct module_param_attrs *new;
 596         struct attribute **attrs;
 597         int err, num;
 598
 599         /* We don't bother calling this with invisible parameters. */
 600         BUG_ON(!kp->perm);
 601
 602         if (!mk->mp) {
 603                 num = 0;
 604                 attrs = NULL;
 605         } else {
 606                 num = mk->mp->num;
 607                 attrs = mk->mp->grp.attrs;
 608         }
 609
 610         /* Enlarge. */
 611         new = krealloc(mk->mp,
 612                        sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
 613                        GFP_KERNEL);
 614         if (!new) {
 615                 kfree(attrs);
 616                 err = -ENOMEM;
 617                 goto fail;
 618         }
 619         /* Despite looking like the typical realloc() bug, this is safe.
 620          * We *want* the old 'attrs' to be freed either way, and we'll store
 621          * the new one in the success case. */
 622         attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
 623         if (!attrs) {
 624                 err = -ENOMEM;
 625                 goto fail_free_new;
 626         }
 627
 628         /* Sysfs wants everything zeroed. */
 629         memset(new, 0, sizeof(*new));
 630         memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
 631         memset(&attrs[num], 0, sizeof(attrs[num]));
 632         new->grp.name = "parameters";
 633         new->grp.attrs = attrs;
 634
 635         /* Tack new one on the end. */
 636         sysfs_attr_init(&new->attrs[num].mattr.attr);
 637         new->attrs[num].param = kp;
 638         new->attrs[num].mattr.show = param_attr_show;
 639         new->attrs[num].mattr.store = param_attr_store;
 640         new->attrs[num].mattr.attr.name = (char *)name;
 641         new->attrs[num].mattr.attr.mode = kp->perm;
 642         new->num = num+1;
 643
 644         /* Fix up all the pointers, since krealloc can move us */
 645         for (num = 0; num < new->num; num++)
 646                 new->grp.attrs[num] = &new->attrs[num].mattr.attr;
 647         new->grp.attrs[num] = NULL;
 648
 649         mk->mp = new;
 650         return 0;
 651
 652 fail_free_new:
 653         kfree(new);
 654 fail:
 655         mk->mp = NULL;
 656         return err;
 657 }
 658
 659 #ifdef CONFIG_MODULES
 660 static void free_module_param_attrs(struct module_kobject *mk)
 661 {
 662         kfree(mk->mp->grp.attrs);
 663         kfree(mk->mp);
 664         mk->mp = NULL;
 665 }
 666
 667 /*
 668  * module_param_sysfs_setup - setup sysfs support for one module
 669  * @mod: module
 670  * @kparam: module parameters (array)
 671  * @num_params: number of module parameters
 672  *
 673  * Adds sysfs entries for module parameters under
 674  * /sys/module/[mod->name]/parameters/
 675  */
 676 int module_param_sysfs_setup(struct module *mod,
 677                              const struct kernel_param *kparam,
 678                              unsigned int num_params)
 679 {
 680         int i, err;
 681         bool params = false;
 682
 683         for (i = 0; i < num_params; i++) {
 684                 if (kparam[i].perm == 0)
 685                         continue;
 686                 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 687                 if (err)
 688                         return err;
 689                 params = true;
 690         }
 691
 692         if (!params)
 693                 return 0;
 694
 695         /* Create the param group. */
 696         err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 697         if (err)
 698                 free_module_param_attrs(&mod->mkobj);
 699         return err;
 700 }
 701
 702 /*
 703  * module_param_sysfs_remove - remove sysfs support for one module
 704  * @mod: module
 705  *
 706  * Remove sysfs entries for module parameters and the corresponding
 707  * kobject.
 708  */
 709 void module_param_sysfs_remove(struct module *mod)
 710 {
 711         if (mod->mkobj.mp) {
 712                 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 713                 /* We are positive that no one is using any param
 714                  * attrs at this point.  Deallocate immediately. */
 715                 free_module_param_attrs(&mod->mkobj);
 716         }
 717 }
 718 #endif
 719
 720 void destroy_params(const struct kernel_param *params, unsigned num)
 721 {
 722         unsigned int i;
 723
 724         for (i = 0; i < num; i++)
 725                 if (params[i].ops->free)
 726                         params[i].ops->free(params[i].arg);
 727 }
 728
 729 static struct module_kobject * __init locate_module_kobject(const char *name)
 730 {
 731         struct module_kobject *mk;
 732         struct kobject *kobj;
 733         int err;
 734
 735         kobj = kset_find_obj(module_kset, name);
 736         if (kobj) {
 737                 mk = to_module_kobject(kobj);
 738         } else {
 739                 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 740                 BUG_ON(!mk);
 741
 742                 mk->mod = THIS_MODULE;
 743                 mk->kobj.kset = module_kset;
 744                 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 745                                            "%s", name);
 746 #ifdef CONFIG_MODULES
 747                 if (!err)
 748                         err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
 749 #endif
 750                 if (err) {
 751                         kobject_put(&mk->kobj);
 752                         pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
 753                                 name, err);
 754                         return NULL;
 755                 }
 756
 757                 /* So that we hold reference in both cases. */
 758                 kobject_get(&mk->kobj);
 759         }
 760
 761         return mk;
 762 }
 763
 764 static void __init kernel_add_sysfs_param(const char *name,
 765                                           struct kernel_param *kparam,
 766                                           unsigned int name_skip)
 767 {
 768         struct module_kobject *mk;
 769         int err;
 770
 771         mk = locate_module_kobject(name);
 772         if (!mk)
 773                 return;
 774
 775         /* We need to remove old parameters before adding more. */
 776         if (mk->mp)
 777                 sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 778
 779         /* These should not fail at boot. */
 780         err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 781         BUG_ON(err);
 782         err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 783         BUG_ON(err);
 784         kobject_uevent(&mk->kobj, KOBJ_ADD);
 785         kobject_put(&mk->kobj);
 786 }
 787
 788 /*
 789  * param_sysfs_builtin - add sysfs parameters for built-in modules
 790  *
 791  * Add module_parameters to sysfs for "modules" built into the kernel.
 792  *
 793  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 794  * "parameter" name is stored behind a dot in kernel_param->name. So,
 795  * extract the "module" name for all built-in kernel_param-eters,
 796  * and for all who have the same, call kernel_add_sysfs_param.
 797  */
 798 static void __init param_sysfs_builtin(void)
 799 {
 800         struct kernel_param *kp;
 801         unsigned int name_len;
 802         char modname[MODULE_NAME_LEN];
 803
 804         for (kp = __start___param; kp < __stop___param; kp++) {
 805                 char *dot;
 806
 807                 if (kp->perm == 0)
 808                         continue;
 809
 810                 dot = strchr(kp->name, '.');
 811                 if (!dot) {
 812                         /* This happens for core_param() */
 813                         strcpy(modname, "kernel");
 814                         name_len = 0;
 815                 } else {
 816                         name_len = dot - kp->name + 1;
 817                         strlcpy(modname, kp->name, name_len);
 818                 }
 819                 kernel_add_sysfs_param(modname, kp, name_len);
 820         }
 821 }
 822
 823 ssize_t __modver_version_show(struct module_attribute *mattr,
 824                               struct module_kobject *mk, char *buf)
 825 {
 826         struct module_version_attribute *vattr =
 827                 container_of(mattr, struct module_version_attribute, mattr);
 828
 829         return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
 830 }
 831
 832 extern const struct module_version_attribute *__start___modver[];
 833 extern const struct module_version_attribute *__stop___modver[];
 834
 835 static void __init version_sysfs_builtin(void)
 836 {
 837         const struct module_version_attribute **p;
 838         struct module_kobject *mk;
 839         int err;
 840
 841         for (p = __start___modver; p < __stop___modver; p++) {
 842                 const struct module_version_attribute *vattr = *p;
 843
 844                 mk = locate_module_kobject(vattr->module_name);
 845                 if (mk) {
 846                         err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
 847                         kobject_uevent(&mk->kobj, KOBJ_ADD);
 848                         kobject_put(&mk->kobj);
 849                 }
 850         }
 851 }
 852
 853 /* module-related sysfs stuff */
 854
 855 static ssize_t module_attr_show(struct kobject *kobj,
 856                                 struct attribute *attr,
 857                                 char *buf)
 858 {
 859         struct module_attribute *attribute;
 860         struct module_kobject *mk;
 861         int ret;
 862
 863         attribute = to_module_attr(attr);
 864         mk = to_module_kobject(kobj);
 865
 866         if (!attribute->show)
 867                 return -EIO;
 868
 869         ret = attribute->show(attribute, mk, buf);
 870
 871         return ret;
 872 }
 873
 874 static ssize_t module_attr_store(struct kobject *kobj,
 875                                 struct attribute *attr,
 876                                 const char *buf, size_t len)
 877 {
 878         struct module_attribute *attribute;
 879         struct module_kobject *mk;
 880         int ret;
 881
 882         attribute = to_module_attr(attr);
 883         mk = to_module_kobject(kobj);
 884
 885         if (!attribute->store)
 886                 return -EIO;
 887
 888         ret = attribute->store(attribute, mk, buf, len);
 889
 890         return ret;
 891 }
 892
 893 static const struct sysfs_ops module_sysfs_ops = {
 894         .show = module_attr_show,
 895         .store = module_attr_store,
 896 };
 897
 898 static int uevent_filter(struct kset *kset, struct kobject *kobj)
 899 {
 900         struct kobj_type *ktype = get_ktype(kobj);
 901
 902         if (ktype == &module_ktype)
 903                 return 1;
 904         return 0;
 905 }
 906
 907 static const struct kset_uevent_ops module_uevent_ops = {
 908         .filter = uevent_filter,
 909 };
 910
 911 struct kset *module_kset;
 912 int module_sysfs_initialized;
 913
 914 static void module_kobj_release(struct kobject *kobj)
 915 {
 916         struct module_kobject *mk = to_module_kobject(kobj);
 917         complete(mk->kobj_completion);
 918 }
 919
 920 struct kobj_type module_ktype = {
 921         .release   =    module_kobj_release,
 922         .sysfs_ops =    &module_sysfs_ops,
 923 };
 924
 925 /*
 926  * param_sysfs_init - wrapper for built-in params support
 927  */
 928 static int __init param_sysfs_init(void)
 929 {
 930         module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
 931         if (!module_kset) {
 932                 printk(KERN_WARNING "%s (%d): error creating kset\n",
 933                         __FILE__, __LINE__);
 934                 return -ENOMEM;
 935         }
 936         module_sysfs_initialized = 1;
 937
 938         version_sysfs_builtin();
 939         param_sysfs_builtin();
 940
 941         return 0;
 942 }
 943 subsys_initcall(param_sysfs_init);
 944
 945 #endif /* CONFIG_SYSFS */