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 /* You can use " around spaces, but can't escape ". */
 164 /* Hyphens and underscores equivalent in parameter names. */
 165 static char *next_arg(char *args, char **param, char **val)
 166 {
 167         unsigned int i, equals = 0;
 168         int in_quote = 0, quoted = 0;
 169         char *next;
 170
 171         if (*args == '"') {
 172                 args++;
 173                 in_quote = 1;
 174                 quoted = 1;
 175         }
 176
 177         for (i = 0; args[i]; i++) {
 178                 if (isspace(args[i]) && !in_quote)
 179                         break;
 180                 if (equals == 0) {
 181                         if (args[i] == '=')
 182                                 equals = i;
 183                 }
 184                 if (args[i] == '"')
 185                         in_quote = !in_quote;
 186         }
 187
 188         *param = args;
 189         if (!equals)
 190                 *val = NULL;
 191         else {
 192                 args[equals] = '\0';
 193                 *val = args + equals + 1;
 194
 195                 /* Don't include quotes in value. */
 196                 if (**val == '"') {
 197                         (*val)++;
 198                         if (args[i-1] == '"')
 199                                 args[i-1] = '\0';
 200                 }
 201         }
 202         if (quoted && args[i-1] == '"')
 203                 args[i-1] = '\0';
 204
 205         if (args[i]) {
 206                 args[i] = '\0';
 207                 next = args + i + 1;
 208         } else
 209                 next = args + i;
 210
 211         /* Chew up trailing spaces. */
 212         return skip_spaces(next);
 213 }
 214
 215 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 216 char *parse_args(const char *doing,
 217                  char *args,
 218                  const struct kernel_param *params,
 219                  unsigned num,
 220                  s16 min_level,
 221                  s16 max_level,
 222                  void *arg,
 223                  int (*unknown)(char *param, char *val,
 224                                 const char *doing, void *arg))
 225 {
 226         char *param, *val;
 227
 228         /* Chew leading spaces */
 229         args = skip_spaces(args);
 230
 231         if (*args)
 232                 pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
 233
 234         while (*args) {
 235                 int ret;
 236                 int irq_was_disabled;
 237
 238                 args = next_arg(args, &param, &val);
 239                 /* Stop at -- */
 240                 if (!val && strcmp(param, "--") == 0)
 241                         return args;
 242                 irq_was_disabled = irqs_disabled();
 243                 ret = parse_one(param, val, doing, params, num,
 244                                 min_level, max_level, arg, unknown);
 245                 if (irq_was_disabled && !irqs_disabled())
 246                         pr_warn("%s: option '%s' enabled irq's!\n",
 247                                 doing, param);
 248
 249                 switch (ret) {
 250                 case -ENOENT:
 251                         pr_err("%s: Unknown parameter `%s'\n", doing, param);
 252                         return ERR_PTR(ret);
 253                 case -ENOSPC:
 254                         pr_err("%s: `%s' too large for parameter `%s'\n",
 255                                doing, val ?: "", param);
 256                         return ERR_PTR(ret);
 257                 case 0:
 258                         break;
 259                 default:
 260                         pr_err("%s: `%s' invalid for parameter `%s'\n",
 261                                doing, val ?: "", param);
 262                         return ERR_PTR(ret);
 263                 }
 264         }
 265
 266         /* All parsed OK. */
 267         return NULL;
 268 }
 269
 270 /* Lazy bastard, eh? */
 271 #define STANDARD_PARAM_DEF(name, type, format, strtolfn)                \
 272         int param_set_##name(const char *val, const struct kernel_param *kp) \
 273         {                                                               \
 274                 return strtolfn(val, 0, (type *)kp->arg);               \
 275         }                                                               \
 276         int param_get_##name(char *buffer, const struct kernel_param *kp) \
 277         {                                                               \
 278                 return scnprintf(buffer, PAGE_SIZE, format,             \
 279                                 *((type *)kp->arg));                    \
 280         }                                                               \
 281         const struct kernel_param_ops param_ops_##name = {                      \
 282                 .set = param_set_##name,                                \
 283                 .get = param_get_##name,                                \
 284         };                                                              \
 285         EXPORT_SYMBOL(param_set_##name);                                \
 286         EXPORT_SYMBOL(param_get_##name);                                \
 287         EXPORT_SYMBOL(param_ops_##name)
 288
 289
 290 STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", kstrtou8);
 291 STANDARD_PARAM_DEF(short, short, "%hi", kstrtos16);
 292 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", kstrtou16);
 293 STANDARD_PARAM_DEF(int, int, "%i", kstrtoint);
 294 STANDARD_PARAM_DEF(uint, unsigned int, "%u", kstrtouint);
 295 STANDARD_PARAM_DEF(long, long, "%li", kstrtol);
 296 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", kstrtoul);
 297 STANDARD_PARAM_DEF(ullong, unsigned long long, "%llu", kstrtoull);
 298
 299 int param_set_charp(const char *val, const struct kernel_param *kp)
 300 {
 301         if (strlen(val) > 1024) {
 302                 pr_err("%s: string parameter too long\n", kp->name);
 303                 return -ENOSPC;
 304         }
 305
 306         maybe_kfree_parameter(*(char **)kp->arg);
 307
 308         /* This is a hack.  We can't kmalloc in early boot, and we
 309          * don't need to; this mangled commandline is preserved. */
 310         if (slab_is_available()) {
 311                 *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
 312                 if (!*(char **)kp->arg)
 313                         return -ENOMEM;
 314                 strcpy(*(char **)kp->arg, val);
 315         } else
 316                 *(const char **)kp->arg = val;
 317
 318         return 0;
 319 }
 320 EXPORT_SYMBOL(param_set_charp);
 321
 322 int param_get_charp(char *buffer, const struct kernel_param *kp)
 323 {
 324         return scnprintf(buffer, PAGE_SIZE, "%s", *((char **)kp->arg));
 325 }
 326 EXPORT_SYMBOL(param_get_charp);
 327
 328 static void param_free_charp(void *arg)
 329 {
 330         maybe_kfree_parameter(*((char **)arg));
 331 }
 332
 333 const struct kernel_param_ops param_ops_charp = {
 334         .set = param_set_charp,
 335         .get = param_get_charp,
 336         .free = param_free_charp,
 337 };
 338 EXPORT_SYMBOL(param_ops_charp);
 339
 340 /* Actually could be a bool or an int, for historical reasons. */
 341 int param_set_bool(const char *val, const struct kernel_param *kp)
 342 {
 343         /* No equals means "set"... */
 344         if (!val) val = "1";
 345
 346         /* One of =[yYnN01] */
 347         return strtobool(val, kp->arg);
 348 }
 349 EXPORT_SYMBOL(param_set_bool);
 350
 351 int param_get_bool(char *buffer, const struct kernel_param *kp)
 352 {
 353         /* Y and N chosen as being relatively non-coder friendly */
 354         return sprintf(buffer, "%c", *(bool *)kp->arg ? 'Y' : 'N');
 355 }
 356 EXPORT_SYMBOL(param_get_bool);
 357
 358 const struct kernel_param_ops param_ops_bool = {
 359         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 360         .set = param_set_bool,
 361         .get = param_get_bool,
 362 };
 363 EXPORT_SYMBOL(param_ops_bool);
 364
 365 int param_set_bool_enable_only(const char *val, const struct kernel_param *kp)
 366 {
 367         int err = 0;
 368         bool new_value;
 369         bool orig_value = *(bool *)kp->arg;
 370         struct kernel_param dummy_kp = *kp;
 371
 372         dummy_kp.arg = &new_value;
 373
 374         err = param_set_bool(val, &dummy_kp);
 375         if (err)
 376                 return err;
 377
 378         /* Don't let them unset it once it's set! */
 379         if (!new_value && orig_value)
 380                 return -EROFS;
 381
 382         if (new_value)
 383                 err = param_set_bool(val, kp);
 384
 385         return err;
 386 }
 387 EXPORT_SYMBOL_GPL(param_set_bool_enable_only);
 388
 389 const struct kernel_param_ops param_ops_bool_enable_only = {
 390         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 391         .set = param_set_bool_enable_only,
 392         .get = param_get_bool,
 393 };
 394 EXPORT_SYMBOL_GPL(param_ops_bool_enable_only);
 395
 396 /* This one must be bool. */
 397 int param_set_invbool(const char *val, const struct kernel_param *kp)
 398 {
 399         int ret;
 400         bool boolval;
 401         struct kernel_param dummy;
 402
 403         dummy.arg = &boolval;
 404         ret = param_set_bool(val, &dummy);
 405         if (ret == 0)
 406                 *(bool *)kp->arg = !boolval;
 407         return ret;
 408 }
 409 EXPORT_SYMBOL(param_set_invbool);
 410
 411 int param_get_invbool(char *buffer, const struct kernel_param *kp)
 412 {
 413         return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
 414 }
 415 EXPORT_SYMBOL(param_get_invbool);
 416
 417 const struct kernel_param_ops param_ops_invbool = {
 418         .set = param_set_invbool,
 419         .get = param_get_invbool,
 420 };
 421 EXPORT_SYMBOL(param_ops_invbool);
 422
 423 int param_set_bint(const char *val, const struct kernel_param *kp)
 424 {
 425         /* Match bool exactly, by re-using it. */
 426         struct kernel_param boolkp = *kp;
 427         bool v;
 428         int ret;
 429
 430         boolkp.arg = &v;
 431
 432         ret = param_set_bool(val, &boolkp);
 433         if (ret == 0)
 434                 *(int *)kp->arg = v;
 435         return ret;
 436 }
 437 EXPORT_SYMBOL(param_set_bint);
 438
 439 const struct kernel_param_ops param_ops_bint = {
 440         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 441         .set = param_set_bint,
 442         .get = param_get_int,
 443 };
 444 EXPORT_SYMBOL(param_ops_bint);
 445
 446 /* We break the rule and mangle the string. */
 447 static int param_array(struct module *mod,
 448                        const char *name,
 449                        const char *val,
 450                        unsigned int min, unsigned int max,
 451                        void *elem, int elemsize,
 452                        int (*set)(const char *, const struct kernel_param *kp),
 453                        s16 level,
 454                        unsigned int *num)
 455 {
 456         int ret;
 457         struct kernel_param kp;
 458         char save;
 459
 460         /* Get the name right for errors. */
 461         kp.name = name;
 462         kp.arg = elem;
 463         kp.level = level;
 464
 465         *num = 0;
 466         /* We expect a comma-separated list of values. */
 467         do {
 468                 int len;
 469
 470                 if (*num == max) {
 471                         pr_err("%s: can only take %i arguments\n", name, max);
 472                         return -EINVAL;
 473                 }
 474                 len = strcspn(val, ",");
 475
 476                 /* nul-terminate and parse */
 477                 save = val[len];
 478                 ((char *)val)[len] = '\0';
 479                 check_kparam_locked(mod);
 480                 ret = set(val, &kp);
 481
 482                 if (ret != 0)
 483                         return ret;
 484                 kp.arg += elemsize;
 485                 val += len+1;
 486                 (*num)++;
 487         } while (save == ',');
 488
 489         if (*num < min) {
 490                 pr_err("%s: needs at least %i arguments\n", name, min);
 491                 return -EINVAL;
 492         }
 493         return 0;
 494 }
 495
 496 static int param_array_set(const char *val, const struct kernel_param *kp)
 497 {
 498         const struct kparam_array *arr = kp->arr;
 499         unsigned int temp_num;
 500
 501         return param_array(kp->mod, kp->name, val, 1, arr->max, arr->elem,
 502                            arr->elemsize, arr->ops->set, kp->level,
 503                            arr->num ?: &temp_num);
 504 }
 505
 506 static int param_array_get(char *buffer, const struct kernel_param *kp)
 507 {
 508         int i, off, ret;
 509         const struct kparam_array *arr = kp->arr;
 510         struct kernel_param p = *kp;
 511
 512         for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 513                 if (i)
 514                         buffer[off++] = ',';
 515                 p.arg = arr->elem + arr->elemsize * i;
 516                 check_kparam_locked(p.mod);
 517                 ret = arr->ops->get(buffer + off, &p);
 518                 if (ret < 0)
 519                         return ret;
 520                 off += ret;
 521         }
 522         buffer[off] = '\0';
 523         return off;
 524 }
 525
 526 static void param_array_free(void *arg)
 527 {
 528         unsigned int i;
 529         const struct kparam_array *arr = arg;
 530
 531         if (arr->ops->free)
 532                 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 533                         arr->ops->free(arr->elem + arr->elemsize * i);
 534 }
 535
 536 const struct kernel_param_ops param_array_ops = {
 537         .set = param_array_set,
 538         .get = param_array_get,
 539         .free = param_array_free,
 540 };
 541 EXPORT_SYMBOL(param_array_ops);
 542
 543 int param_set_copystring(const char *val, const struct kernel_param *kp)
 544 {
 545         const struct kparam_string *kps = kp->str;
 546
 547         if (strlen(val)+1 > kps->maxlen) {
 548                 pr_err("%s: string doesn't fit in %u chars.\n",
 549                        kp->name, kps->maxlen-1);
 550                 return -ENOSPC;
 551         }
 552         strcpy(kps->string, val);
 553         return 0;
 554 }
 555 EXPORT_SYMBOL(param_set_copystring);
 556
 557 int param_get_string(char *buffer, const struct kernel_param *kp)
 558 {
 559         const struct kparam_string *kps = kp->str;
 560         return strlcpy(buffer, kps->string, kps->maxlen);
 561 }
 562 EXPORT_SYMBOL(param_get_string);
 563
 564 const struct kernel_param_ops param_ops_string = {
 565         .set = param_set_copystring,
 566         .get = param_get_string,
 567 };
 568 EXPORT_SYMBOL(param_ops_string);
 569
 570 /* sysfs output in /sys/modules/XYZ/parameters/ */
 571 #define to_module_attr(n) container_of(n, struct module_attribute, attr)
 572 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 573
 574 struct param_attribute
 575 {
 576         struct module_attribute mattr;
 577         const struct kernel_param *param;
 578 };
 579
 580 struct module_param_attrs
 581 {
 582         unsigned int num;
 583         struct attribute_group grp;
 584         struct param_attribute attrs[0];
 585 };
 586
 587 #ifdef CONFIG_SYSFS
 588 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 589
 590 static ssize_t param_attr_show(struct module_attribute *mattr,
 591                                struct module_kobject *mk, char *buf)
 592 {
 593         int count;
 594         struct param_attribute *attribute = to_param_attr(mattr);
 595
 596         if (!attribute->param->ops->get)
 597                 return -EPERM;
 598
 599         kernel_param_lock(mk->mod);
 600         count = attribute->param->ops->get(buf, attribute->param);
 601         kernel_param_unlock(mk->mod);
 602         if (count > 0) {
 603                 strcat(buf, "\n");
 604                 ++count;
 605         }
 606         return count;
 607 }
 608
 609 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 610 static ssize_t param_attr_store(struct module_attribute *mattr,
 611                                 struct module_kobject *mk,
 612                                 const char *buf, size_t len)
 613 {
 614         int err;
 615         struct param_attribute *attribute = to_param_attr(mattr);
 616
 617         if (!attribute->param->ops->set)
 618                 return -EPERM;
 619
 620         kernel_param_lock(mk->mod);
 621         param_check_unsafe(attribute->param);
 622         err = attribute->param->ops->set(buf, attribute->param);
 623         kernel_param_unlock(mk->mod);
 624         if (!err)
 625                 return len;
 626         return err;
 627 }
 628 #endif
 629
 630 #ifdef CONFIG_MODULES
 631 #define __modinit
 632 #else
 633 #define __modinit __init
 634 #endif
 635
 636 #ifdef CONFIG_SYSFS
 637 void kernel_param_lock(struct module *mod)
 638 {
 639         mutex_lock(KPARAM_MUTEX(mod));
 640 }
 641
 642 void kernel_param_unlock(struct module *mod)
 643 {
 644         mutex_unlock(KPARAM_MUTEX(mod));
 645 }
 646
 647 EXPORT_SYMBOL(kernel_param_lock);
 648 EXPORT_SYMBOL(kernel_param_unlock);
 649
 650 /*
 651  * add_sysfs_param - add a parameter to sysfs
 652  * @mk: struct module_kobject
 653  * @kparam: the actual parameter definition to add to sysfs
 654  * @name: name of parameter
 655  *
 656  * Create a kobject if for a (per-module) parameter if mp NULL, and
 657  * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 658  * if there's an error.
 659  */
 660 static __modinit int add_sysfs_param(struct module_kobject *mk,
 661                                      const struct kernel_param *kp,
 662                                      const char *name)
 663 {
 664         struct module_param_attrs *new_mp;
 665         struct attribute **new_attrs;
 666         unsigned int i;
 667
 668         /* We don't bother calling this with invisible parameters. */
 669         BUG_ON(!kp->perm);
 670
 671         if (!mk->mp) {
 672                 /* First allocation. */
 673                 mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL);
 674                 if (!mk->mp)
 675                         return -ENOMEM;
 676                 mk->mp->grp.name = "parameters";
 677                 /* NULL-terminated attribute array. */
 678                 mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]),
 679                                             GFP_KERNEL);
 680                 /* Caller will cleanup via free_module_param_attrs */
 681                 if (!mk->mp->grp.attrs)
 682                         return -ENOMEM;
 683         }
 684
 685         /* Enlarge allocations. */
 686         new_mp = krealloc(mk->mp,
 687                           sizeof(*mk->mp) +
 688                           sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1),
 689                           GFP_KERNEL);
 690         if (!new_mp)
 691                 return -ENOMEM;
 692         mk->mp = new_mp;
 693
 694         /* Extra pointer for NULL terminator */
 695         new_attrs = krealloc(mk->mp->grp.attrs,
 696                              sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2),
 697                              GFP_KERNEL);
 698         if (!new_attrs)
 699                 return -ENOMEM;
 700         mk->mp->grp.attrs = new_attrs;
 701
 702         /* Tack new one on the end. */
 703         memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0]));
 704         sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr);
 705         mk->mp->attrs[mk->mp->num].param = kp;
 706         mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show;
 707         /* Do not allow runtime DAC changes to make param writable. */
 708         if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0)
 709                 mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store;
 710         else
 711                 mk->mp->attrs[mk->mp->num].mattr.store = NULL;
 712         mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name;
 713         mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm;
 714         mk->mp->num++;
 715
 716         /* Fix up all the pointers, since krealloc can move us */
 717         for (i = 0; i < mk->mp->num; i++)
 718                 mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr;
 719         mk->mp->grp.attrs[mk->mp->num] = NULL;
 720         return 0;
 721 }
 722
 723 #ifdef CONFIG_MODULES
 724 static void free_module_param_attrs(struct module_kobject *mk)
 725 {
 726         if (mk->mp)
 727                 kfree(mk->mp->grp.attrs);
 728         kfree(mk->mp);
 729         mk->mp = NULL;
 730 }
 731
 732 /*
 733  * module_param_sysfs_setup - setup sysfs support for one module
 734  * @mod: module
 735  * @kparam: module parameters (array)
 736  * @num_params: number of module parameters
 737  *
 738  * Adds sysfs entries for module parameters under
 739  * /sys/module/[mod->name]/parameters/
 740  */
 741 int module_param_sysfs_setup(struct module *mod,
 742                              const struct kernel_param *kparam,
 743                              unsigned int num_params)
 744 {
 745         int i, err;
 746         bool params = false;
 747
 748         for (i = 0; i < num_params; i++) {
 749                 if (kparam[i].perm == 0)
 750                         continue;
 751                 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 752                 if (err) {
 753                         free_module_param_attrs(&mod->mkobj);
 754                         return err;
 755                 }
 756                 params = true;
 757         }
 758
 759         if (!params)
 760                 return 0;
 761
 762         /* Create the param group. */
 763         err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 764         if (err)
 765                 free_module_param_attrs(&mod->mkobj);
 766         return err;
 767 }
 768
 769 /*
 770  * module_param_sysfs_remove - remove sysfs support for one module
 771  * @mod: module
 772  *
 773  * Remove sysfs entries for module parameters and the corresponding
 774  * kobject.
 775  */
 776 void module_param_sysfs_remove(struct module *mod)
 777 {
 778         if (mod->mkobj.mp) {
 779                 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 780                 /* We are positive that no one is using any param
 781                  * attrs at this point.  Deallocate immediately. */
 782                 free_module_param_attrs(&mod->mkobj);
 783         }
 784 }
 785 #endif
 786
 787 void destroy_params(const struct kernel_param *params, unsigned num)
 788 {
 789         unsigned int i;
 790
 791         for (i = 0; i < num; i++)
 792                 if (params[i].ops->free)
 793                         params[i].ops->free(params[i].arg);
 794 }
 795
 796 static struct module_kobject * __init locate_module_kobject(const char *name)
 797 {
 798         struct module_kobject *mk;
 799         struct kobject *kobj;
 800         int err;
 801
 802         kobj = kset_find_obj(module_kset, name);
 803         if (kobj) {
 804                 mk = to_module_kobject(kobj);
 805         } else {
 806                 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 807                 BUG_ON(!mk);
 808
 809                 mk->mod = THIS_MODULE;
 810                 mk->kobj.kset = module_kset;
 811                 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 812                                            "%s", name);
 813 #ifdef CONFIG_MODULES
 814                 if (!err)
 815                         err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
 816 #endif
 817                 if (err) {
 818                         kobject_put(&mk->kobj);
 819                         pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
 820                                 name, err);
 821                         return NULL;
 822                 }
 823
 824                 /* So that we hold reference in both cases. */
 825                 kobject_get(&mk->kobj);
 826         }
 827
 828         return mk;
 829 }
 830
 831 static void __init kernel_add_sysfs_param(const char *name,
 832                                           const struct kernel_param *kparam,
 833                                           unsigned int name_skip)
 834 {
 835         struct module_kobject *mk;
 836         int err;
 837
 838         mk = locate_module_kobject(name);
 839         if (!mk)
 840                 return;
 841
 842         /* We need to remove old parameters before adding more. */
 843         if (mk->mp)
 844                 sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 845
 846         /* These should not fail at boot. */
 847         err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 848         BUG_ON(err);
 849         err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 850         BUG_ON(err);
 851         kobject_uevent(&mk->kobj, KOBJ_ADD);
 852         kobject_put(&mk->kobj);
 853 }
 854
 855 /*
 856  * param_sysfs_builtin - add sysfs parameters for built-in modules
 857  *
 858  * Add module_parameters to sysfs for "modules" built into the kernel.
 859  *
 860  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 861  * "parameter" name is stored behind a dot in kernel_param->name. So,
 862  * extract the "module" name for all built-in kernel_param-eters,
 863  * and for all who have the same, call kernel_add_sysfs_param.
 864  */
 865 static void __init param_sysfs_builtin(void)
 866 {
 867         const struct kernel_param *kp;
 868         unsigned int name_len;
 869         char modname[MODULE_NAME_LEN];
 870
 871         for (kp = __start___param; kp < __stop___param; kp++) {
 872                 char *dot;
 873
 874                 if (kp->perm == 0)
 875                         continue;
 876
 877                 dot = strchr(kp->name, '.');
 878                 if (!dot) {
 879                         /* This happens for core_param() */
 880                         strcpy(modname, "kernel");
 881                         name_len = 0;
 882                 } else {
 883                         name_len = dot - kp->name + 1;
 884                         strlcpy(modname, kp->name, name_len);
 885                 }
 886                 kernel_add_sysfs_param(modname, kp, name_len);
 887         }
 888 }
 889
 890 ssize_t __modver_version_show(struct module_attribute *mattr,
 891                               struct module_kobject *mk, char *buf)
 892 {
 893         struct module_version_attribute *vattr =
 894                 container_of(mattr, struct module_version_attribute, mattr);
 895
 896         return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
 897 }
 898
 899 extern const struct module_version_attribute *__start___modver[];
 900 extern const struct module_version_attribute *__stop___modver[];
 901
 902 static void __init version_sysfs_builtin(void)
 903 {
 904         const struct module_version_attribute **p;
 905         struct module_kobject *mk;
 906         int err;
 907
 908         for (p = __start___modver; p < __stop___modver; p++) {
 909                 const struct module_version_attribute *vattr = *p;
 910
 911                 mk = locate_module_kobject(vattr->module_name);
 912                 if (mk) {
 913                         err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
 914                         WARN_ON_ONCE(err);
 915                         kobject_uevent(&mk->kobj, KOBJ_ADD);
 916                         kobject_put(&mk->kobj);
 917                 }
 918         }
 919 }
 920
 921 /* module-related sysfs stuff */
 922
 923 static ssize_t module_attr_show(struct kobject *kobj,
 924                                 struct attribute *attr,
 925                                 char *buf)
 926 {
 927         struct module_attribute *attribute;
 928         struct module_kobject *mk;
 929         int ret;
 930
 931         attribute = to_module_attr(attr);
 932         mk = to_module_kobject(kobj);
 933
 934         if (!attribute->show)
 935                 return -EIO;
 936
 937         ret = attribute->show(attribute, mk, buf);
 938
 939         return ret;
 940 }
 941
 942 static ssize_t module_attr_store(struct kobject *kobj,
 943                                 struct attribute *attr,
 944                                 const char *buf, size_t len)
 945 {
 946         struct module_attribute *attribute;
 947         struct module_kobject *mk;
 948         int ret;
 949
 950         attribute = to_module_attr(attr);
 951         mk = to_module_kobject(kobj);
 952
 953         if (!attribute->store)
 954                 return -EIO;
 955
 956         ret = attribute->store(attribute, mk, buf, len);
 957
 958         return ret;
 959 }
 960
 961 static const struct sysfs_ops module_sysfs_ops = {
 962         .show = module_attr_show,
 963         .store = module_attr_store,
 964 };
 965
 966 static int uevent_filter(struct kset *kset, struct kobject *kobj)
 967 {
 968         struct kobj_type *ktype = get_ktype(kobj);
 969
 970         if (ktype == &module_ktype)
 971                 return 1;
 972         return 0;
 973 }
 974
 975 static const struct kset_uevent_ops module_uevent_ops = {
 976         .filter = uevent_filter,
 977 };
 978
 979 struct kset *module_kset;
 980 int module_sysfs_initialized;
 981
 982 static void module_kobj_release(struct kobject *kobj)
 983 {
 984         struct module_kobject *mk = to_module_kobject(kobj);
 985         complete(mk->kobj_completion);
 986 }
 987
 988 struct kobj_type module_ktype = {
 989         .release   =    module_kobj_release,
 990         .sysfs_ops =    &module_sysfs_ops,
 991 };
 992
 993 /*
 994  * param_sysfs_init - wrapper for built-in params support
 995  */
 996 static int __init param_sysfs_init(void)
 997 {
 998         module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
 999         if (!module_kset) {
1000                 printk(KERN_WARNING "%s (%d): error creating kset\n",
1001                         __FILE__, __LINE__);
1002                 return -ENOMEM;
1003         }
1004         module_sysfs_initialized = 1;
1005
1006         version_sysfs_builtin();
1007         param_sysfs_builtin();
1008
1009         return 0;
1010 }
1011 subsys_initcall(param_sysfs_init);
1012
1013 #endif /* CONFIG_SYSFS */