kernel/params.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Helpers for initial module or kernel cmdline parsing
   4  * Copyright (C) 2001 Rusty Russell.
   5  */
   6 #include <linux/ctype.h>
   7 #include <linux/device.h>
   8 #include <linux/err.h>
   9 #include <linux/errno.h>
  10 #include <linux/kernel.h>
  11 #include <linux/kstrtox.h>
  12 #include <linux/module.h>
  13 #include <linux/moduleparam.h>
  14 #include <linux/overflow.h>
  15 #include <linux/security.h>
  16 #include <linux/slab.h>
  17 #include <linux/string.h>
  18
  19 #ifdef CONFIG_SYSFS
  20 /* Protects all built-in parameters, modules use their own param_lock */
  21 static DEFINE_MUTEX(param_lock);
  22
  23 /* Use the module's mutex, or if built-in use the built-in mutex */
  24 #ifdef CONFIG_MODULES
  25 #define KPARAM_MUTEX(mod)       ((mod) ? &(mod)->param_lock : &param_lock)
  26 #else
  27 #define KPARAM_MUTEX(mod)       (&param_lock)
  28 #endif
  29
  30 static inline void check_kparam_locked(struct module *mod)
  31 {
  32         BUG_ON(!mutex_is_locked(KPARAM_MUTEX(mod)));
  33 }
  34 #else
  35 static inline void check_kparam_locked(struct module *mod)
  36 {
  37 }
  38 #endif /* !CONFIG_SYSFS */
  39
  40 /* This just allows us to keep track of which parameters are kmalloced. */
  41 struct kmalloced_param {
  42         struct list_head list;
  43         char val[];
  44 };
  45 static LIST_HEAD(kmalloced_params);
  46 static DEFINE_SPINLOCK(kmalloced_params_lock);
  47
  48 static void *kmalloc_parameter(unsigned int size)
  49 {
  50         struct kmalloced_param *p;
  51
  52         p = kmalloc(size_add(sizeof(*p), size), GFP_KERNEL);
  53         if (!p)
  54                 return NULL;
  55
  56         spin_lock(&kmalloced_params_lock);
  57         list_add(&p->list, &kmalloced_params);
  58         spin_unlock(&kmalloced_params_lock);
  59
  60         return p->val;
  61 }
  62
  63 /* Does nothing if parameter wasn't kmalloced above. */
  64 static void maybe_kfree_parameter(void *param)
  65 {
  66         struct kmalloced_param *p;
  67
  68         spin_lock(&kmalloced_params_lock);
  69         list_for_each_entry(p, &kmalloced_params, list) {
  70                 if (p->val == param) {
  71                         list_del(&p->list);
  72                         kfree(p);
  73                         break;
  74                 }
  75         }
  76         spin_unlock(&kmalloced_params_lock);
  77 }
  78
  79 static char dash2underscore(char c)
  80 {
  81         if (c == '-')
  82                 return '_';
  83         return c;
  84 }
  85
  86 bool parameqn(const char *a, const char *b, size_t n)
  87 {
  88         size_t i;
  89
  90         for (i = 0; i < n; i++) {
  91                 if (dash2underscore(a[i]) != dash2underscore(b[i]))
  92                         return false;
  93         }
  94         return true;
  95 }
  96
  97 bool parameq(const char *a, const char *b)
  98 {
  99         return parameqn(a, b, strlen(a)+1);
 100 }
 101
 102 static bool param_check_unsafe(const struct kernel_param *kp)
 103 {
 104         if (kp->flags & KERNEL_PARAM_FL_HWPARAM &&
 105             security_locked_down(LOCKDOWN_MODULE_PARAMETERS))
 106                 return false;
 107
 108         if (kp->flags & KERNEL_PARAM_FL_UNSAFE) {
 109                 pr_notice("Setting dangerous option %s - tainting kernel\n",
 110                           kp->name);
 111                 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 112         }
 113
 114         return true;
 115 }
 116
 117 static int parse_one(char *param,
 118                      char *val,
 119                      const char *doing,
 120                      const struct kernel_param *params,
 121                      unsigned num_params,
 122                      s16 min_level,
 123                      s16 max_level,
 124                      void *arg, parse_unknown_fn handle_unknown)
 125 {
 126         unsigned int i;
 127         int err;
 128
 129         /* Find parameter */
 130         for (i = 0; i < num_params; i++) {
 131                 if (parameq(param, params[i].name)) {
 132                         if (params[i].level < min_level
 133                             || params[i].level > max_level)
 134                                 return 0;
 135                         /* No one handled NULL, so do it here. */
 136                         if (!val &&
 137                             !(params[i].ops->flags & KERNEL_PARAM_OPS_FL_NOARG))
 138                                 return -EINVAL;
 139                         pr_debug("handling %s with %p\n", param,
 140                                 params[i].ops->set);
 141                         kernel_param_lock(params[i].mod);
 142                         if (param_check_unsafe(&params[i]))
 143                                 err = params[i].ops->set(val, &params[i]);
 144                         else
 145                                 err = -EPERM;
 146                         kernel_param_unlock(params[i].mod);
 147                         return err;
 148                 }
 149         }
 150
 151         if (handle_unknown) {
 152                 pr_debug("doing %s: %s='%s'\n", doing, param, val);
 153                 return handle_unknown(param, val, doing, arg);
 154         }
 155
 156         pr_debug("Unknown argument '%s'\n", param);
 157         return -ENOENT;
 158 }
 159
 160 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 161 char *parse_args(const char *doing,
 162                  char *args,
 163                  const struct kernel_param *params,
 164                  unsigned num,
 165                  s16 min_level,
 166                  s16 max_level,
 167                  void *arg, parse_unknown_fn unknown)
 168 {
 169         char *param, *val, *err = NULL;
 170
 171         /* Chew leading spaces */
 172         args = skip_spaces(args);
 173
 174         if (*args)
 175                 pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
 176
 177         while (*args) {
 178                 int ret;
 179                 int irq_was_disabled;
 180
 181                 args = next_arg(args, &param, &val);
 182                 /* Stop at -- */
 183                 if (!val && strcmp(param, "--") == 0)
 184                         return err ?: args;
 185                 irq_was_disabled = irqs_disabled();
 186                 ret = parse_one(param, val, doing, params, num,
 187                                 min_level, max_level, arg, unknown);
 188                 if (irq_was_disabled && !irqs_disabled())
 189                         pr_warn("%s: option '%s' enabled irq's!\n",
 190                                 doing, param);
 191
 192                 switch (ret) {
 193                 case 0:
 194                         continue;
 195                 case -ENOENT:
 196                         pr_err("%s: Unknown parameter `%s'\n", doing, param);
 197                         break;
 198                 case -ENOSPC:
 199                         pr_err("%s: `%s' too large for parameter `%s'\n",
 200                                doing, val ?: "", param);
 201                         break;
 202                 default:
 203                         pr_err("%s: `%s' invalid for parameter `%s'\n",
 204                                doing, val ?: "", param);
 205                         break;
 206                 }
 207
 208                 err = ERR_PTR(ret);
 209         }
 210
 211         return err;
 212 }
 213
 214 /* Lazy bastard, eh? */
 215 #define STANDARD_PARAM_DEF(name, type, format, strtolfn)                \
 216         int param_set_##name(const char *val, const struct kernel_param *kp) \
 217         {                                                               \
 218                 return strtolfn(val, 0, (type *)kp->arg);               \
 219         }                                                               \
 220         int param_get_##name(char *buffer, const struct kernel_param *kp) \
 221         {                                                               \
 222                 return scnprintf(buffer, PAGE_SIZE, format "\n",        \
 223                                 *((type *)kp->arg));                    \
 224         }                                                               \
 225         const struct kernel_param_ops param_ops_##name = {                      \
 226                 .set = param_set_##name,                                \
 227                 .get = param_get_##name,                                \
 228         };                                                              \
 229         EXPORT_SYMBOL(param_set_##name);                                \
 230         EXPORT_SYMBOL(param_get_##name);                                \
 231         EXPORT_SYMBOL(param_ops_##name)
 232
 233
 234 STANDARD_PARAM_DEF(byte,        unsigned char,          "%hhu",         kstrtou8);
 235 STANDARD_PARAM_DEF(short,       short,                  "%hi",          kstrtos16);
 236 STANDARD_PARAM_DEF(ushort,      unsigned short,         "%hu",          kstrtou16);
 237 STANDARD_PARAM_DEF(int,         int,                    "%i",           kstrtoint);
 238 STANDARD_PARAM_DEF(uint,        unsigned int,           "%u",           kstrtouint);
 239 STANDARD_PARAM_DEF(long,        long,                   "%li",          kstrtol);
 240 STANDARD_PARAM_DEF(ulong,       unsigned long,          "%lu",          kstrtoul);
 241 STANDARD_PARAM_DEF(ullong,      unsigned long long,     "%llu",         kstrtoull);
 242 STANDARD_PARAM_DEF(hexint,      unsigned int,           "%#08x",        kstrtouint);
 243
 244 int param_set_uint_minmax(const char *val, const struct kernel_param *kp,
 245                 unsigned int min, unsigned int max)
 246 {
 247         unsigned int num;
 248         int ret;
 249
 250         if (!val)
 251                 return -EINVAL;
 252         ret = kstrtouint(val, 0, &num);
 253         if (ret)
 254                 return ret;
 255         if (num < min || num > max)
 256                 return -EINVAL;
 257         *((unsigned int *)kp->arg) = num;
 258         return 0;
 259 }
 260 EXPORT_SYMBOL_GPL(param_set_uint_minmax);
 261
 262 int param_set_charp(const char *val, const struct kernel_param *kp)
 263 {
 264         size_t len, maxlen = 1024;
 265
 266         len = strnlen(val, maxlen + 1);
 267         if (len == maxlen + 1) {
 268                 pr_err("%s: string parameter too long\n", kp->name);
 269                 return -ENOSPC;
 270         }
 271
 272         maybe_kfree_parameter(*(char **)kp->arg);
 273
 274         /*
 275          * This is a hack. We can't kmalloc() in early boot, and we
 276          * don't need to; this mangled commandline is preserved.
 277          */
 278         if (slab_is_available()) {
 279                 *(char **)kp->arg = kmalloc_parameter(len + 1);
 280                 if (!*(char **)kp->arg)
 281                         return -ENOMEM;
 282                 strcpy(*(char **)kp->arg, val);
 283         } else
 284                 *(const char **)kp->arg = val;
 285
 286         return 0;
 287 }
 288 EXPORT_SYMBOL(param_set_charp);
 289
 290 int param_get_charp(char *buffer, const struct kernel_param *kp)
 291 {
 292         return scnprintf(buffer, PAGE_SIZE, "%s\n", *((char **)kp->arg));
 293 }
 294 EXPORT_SYMBOL(param_get_charp);
 295
 296 void param_free_charp(void *arg)
 297 {
 298         maybe_kfree_parameter(*((char **)arg));
 299 }
 300 EXPORT_SYMBOL(param_free_charp);
 301
 302 const struct kernel_param_ops param_ops_charp = {
 303         .set = param_set_charp,
 304         .get = param_get_charp,
 305         .free = param_free_charp,
 306 };
 307 EXPORT_SYMBOL(param_ops_charp);
 308
 309 /* Actually could be a bool or an int, for historical reasons. */
 310 int param_set_bool(const char *val, const struct kernel_param *kp)
 311 {
 312         /* No equals means "set"... */
 313         if (!val) val = "1";
 314
 315         /* One of =[yYnN01] */
 316         return kstrtobool(val, kp->arg);
 317 }
 318 EXPORT_SYMBOL(param_set_bool);
 319
 320 int param_get_bool(char *buffer, const struct kernel_param *kp)
 321 {
 322         /* Y and N chosen as being relatively non-coder friendly */
 323         return sprintf(buffer, "%c\n", *(bool *)kp->arg ? 'Y' : 'N');
 324 }
 325 EXPORT_SYMBOL(param_get_bool);
 326
 327 const struct kernel_param_ops param_ops_bool = {
 328         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 329         .set = param_set_bool,
 330         .get = param_get_bool,
 331 };
 332 EXPORT_SYMBOL(param_ops_bool);
 333
 334 int param_set_bool_enable_only(const char *val, const struct kernel_param *kp)
 335 {
 336         int err;
 337         bool new_value;
 338         bool orig_value = *(bool *)kp->arg;
 339         struct kernel_param dummy_kp = *kp;
 340
 341         dummy_kp.arg = &new_value;
 342
 343         err = param_set_bool(val, &dummy_kp);
 344         if (err)
 345                 return err;
 346
 347         /* Don't let them unset it once it's set! */
 348         if (!new_value && orig_value)
 349                 return -EROFS;
 350
 351         if (new_value)
 352                 err = param_set_bool(val, kp);
 353
 354         return err;
 355 }
 356 EXPORT_SYMBOL_GPL(param_set_bool_enable_only);
 357
 358 const struct kernel_param_ops param_ops_bool_enable_only = {
 359         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 360         .set = param_set_bool_enable_only,
 361         .get = param_get_bool,
 362 };
 363 EXPORT_SYMBOL_GPL(param_ops_bool_enable_only);
 364
 365 /* This one must be bool. */
 366 int param_set_invbool(const char *val, const struct kernel_param *kp)
 367 {
 368         int ret;
 369         bool boolval;
 370         struct kernel_param dummy;
 371
 372         dummy.arg = &boolval;
 373         ret = param_set_bool(val, &dummy);
 374         if (ret == 0)
 375                 *(bool *)kp->arg = !boolval;
 376         return ret;
 377 }
 378 EXPORT_SYMBOL(param_set_invbool);
 379
 380 int param_get_invbool(char *buffer, const struct kernel_param *kp)
 381 {
 382         return sprintf(buffer, "%c\n", (*(bool *)kp->arg) ? 'N' : 'Y');
 383 }
 384 EXPORT_SYMBOL(param_get_invbool);
 385
 386 const struct kernel_param_ops param_ops_invbool = {
 387         .set = param_set_invbool,
 388         .get = param_get_invbool,
 389 };
 390 EXPORT_SYMBOL(param_ops_invbool);
 391
 392 int param_set_bint(const char *val, const struct kernel_param *kp)
 393 {
 394         /* Match bool exactly, by re-using it. */
 395         struct kernel_param boolkp = *kp;
 396         bool v;
 397         int ret;
 398
 399         boolkp.arg = &v;
 400
 401         ret = param_set_bool(val, &boolkp);
 402         if (ret == 0)
 403                 *(int *)kp->arg = v;
 404         return ret;
 405 }
 406 EXPORT_SYMBOL(param_set_bint);
 407
 408 const struct kernel_param_ops param_ops_bint = {
 409         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 410         .set = param_set_bint,
 411         .get = param_get_int,
 412 };
 413 EXPORT_SYMBOL(param_ops_bint);
 414
 415 /* We break the rule and mangle the string. */
 416 static int param_array(struct module *mod,
 417                        const char *name,
 418                        const char *val,
 419                        unsigned int min, unsigned int max,
 420                        void *elem, int elemsize,
 421                        int (*set)(const char *, const struct kernel_param *kp),
 422                        s16 level,
 423                        unsigned int *num)
 424 {
 425         int ret;
 426         struct kernel_param kp;
 427         char save;
 428
 429         /* Get the name right for errors. */
 430         kp.name = name;
 431         kp.arg = elem;
 432         kp.level = level;
 433
 434         *num = 0;
 435         /* We expect a comma-separated list of values. */
 436         do {
 437                 int len;
 438
 439                 if (*num == max) {
 440                         pr_err("%s: can only take %i arguments\n", name, max);
 441                         return -EINVAL;
 442                 }
 443                 len = strcspn(val, ",");
 444
 445                 /* nul-terminate and parse */
 446                 save = val[len];
 447                 ((char *)val)[len] = '\0';
 448                 check_kparam_locked(mod);
 449                 ret = set(val, &kp);
 450
 451                 if (ret != 0)
 452                         return ret;
 453                 kp.arg += elemsize;
 454                 val += len+1;
 455                 (*num)++;
 456         } while (save == ',');
 457
 458         if (*num < min) {
 459                 pr_err("%s: needs at least %i arguments\n", name, min);
 460                 return -EINVAL;
 461         }
 462         return 0;
 463 }
 464
 465 static int param_array_set(const char *val, const struct kernel_param *kp)
 466 {
 467         const struct kparam_array *arr = kp->arr;
 468         unsigned int temp_num;
 469
 470         return param_array(kp->mod, kp->name, val, 1, arr->max, arr->elem,
 471                            arr->elemsize, arr->ops->set, kp->level,
 472                            arr->num ?: &temp_num);
 473 }
 474
 475 static int param_array_get(char *buffer, const struct kernel_param *kp)
 476 {
 477         int i, off, ret;
 478         const struct kparam_array *arr = kp->arr;
 479         struct kernel_param p = *kp;
 480
 481         for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 482                 /* Replace \n with comma */
 483                 if (i)
 484                         buffer[off - 1] = ',';
 485                 p.arg = arr->elem + arr->elemsize * i;
 486                 check_kparam_locked(p.mod);
 487                 ret = arr->ops->get(buffer + off, &p);
 488                 if (ret < 0)
 489                         return ret;
 490                 off += ret;
 491         }
 492         buffer[off] = '\0';
 493         return off;
 494 }
 495
 496 static void param_array_free(void *arg)
 497 {
 498         unsigned int i;
 499         const struct kparam_array *arr = arg;
 500
 501         if (arr->ops->free)
 502                 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 503                         arr->ops->free(arr->elem + arr->elemsize * i);
 504 }
 505
 506 const struct kernel_param_ops param_array_ops = {
 507         .set = param_array_set,
 508         .get = param_array_get,
 509         .free = param_array_free,
 510 };
 511 EXPORT_SYMBOL(param_array_ops);
 512
 513 int param_set_copystring(const char *val, const struct kernel_param *kp)
 514 {
 515         const struct kparam_string *kps = kp->str;
 516
 517         if (strnlen(val, kps->maxlen) == kps->maxlen) {
 518                 pr_err("%s: string doesn't fit in %u chars.\n",
 519                        kp->name, kps->maxlen-1);
 520                 return -ENOSPC;
 521         }
 522         strcpy(kps->string, val);
 523         return 0;
 524 }
 525 EXPORT_SYMBOL(param_set_copystring);
 526
 527 int param_get_string(char *buffer, const struct kernel_param *kp)
 528 {
 529         const struct kparam_string *kps = kp->str;
 530         return scnprintf(buffer, PAGE_SIZE, "%s\n", kps->string);
 531 }
 532 EXPORT_SYMBOL(param_get_string);
 533
 534 const struct kernel_param_ops param_ops_string = {
 535         .set = param_set_copystring,
 536         .get = param_get_string,
 537 };
 538 EXPORT_SYMBOL(param_ops_string);
 539
 540 /* sysfs output in /sys/modules/XYZ/parameters/ */
 541 #define to_module_attr(n) container_of(n, struct module_attribute, attr)
 542 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 543
 544 struct param_attribute
 545 {
 546         struct module_attribute mattr;
 547         const struct kernel_param *param;
 548 };
 549
 550 struct module_param_attrs
 551 {
 552         unsigned int num;
 553         struct attribute_group grp;
 554         struct param_attribute attrs[];
 555 };
 556
 557 #ifdef CONFIG_SYSFS
 558 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 559
 560 static ssize_t param_attr_show(struct module_attribute *mattr,
 561                                struct module_kobject *mk, char *buf)
 562 {
 563         int count;
 564         struct param_attribute *attribute = to_param_attr(mattr);
 565
 566         if (!attribute->param->ops->get)
 567                 return -EPERM;
 568
 569         kernel_param_lock(mk->mod);
 570         count = attribute->param->ops->get(buf, attribute->param);
 571         kernel_param_unlock(mk->mod);
 572         return count;
 573 }
 574
 575 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 576 static ssize_t param_attr_store(struct module_attribute *mattr,
 577                                 struct module_kobject *mk,
 578                                 const char *buf, size_t len)
 579 {
 580         int err;
 581         struct param_attribute *attribute = to_param_attr(mattr);
 582
 583         if (!attribute->param->ops->set)
 584                 return -EPERM;
 585
 586         kernel_param_lock(mk->mod);
 587         if (param_check_unsafe(attribute->param))
 588                 err = attribute->param->ops->set(buf, attribute->param);
 589         else
 590                 err = -EPERM;
 591         kernel_param_unlock(mk->mod);
 592         if (!err)
 593                 return len;
 594         return err;
 595 }
 596 #endif
 597
 598 #ifdef CONFIG_MODULES
 599 #define __modinit
 600 #else
 601 #define __modinit __init
 602 #endif
 603
 604 #ifdef CONFIG_SYSFS
 605 void kernel_param_lock(struct module *mod)
 606 {
 607         mutex_lock(KPARAM_MUTEX(mod));
 608 }
 609
 610 void kernel_param_unlock(struct module *mod)
 611 {
 612         mutex_unlock(KPARAM_MUTEX(mod));
 613 }
 614
 615 EXPORT_SYMBOL(kernel_param_lock);
 616 EXPORT_SYMBOL(kernel_param_unlock);
 617
 618 /*
 619  * add_sysfs_param - add a parameter to sysfs
 620  * @mk: struct module_kobject
 621  * @kp: the actual parameter definition to add to sysfs
 622  * @name: name of parameter
 623  *
 624  * Create a kobject if for a (per-module) parameter if mp NULL, and
 625  * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 626  * if there's an error.
 627  */
 628 static __modinit int add_sysfs_param(struct module_kobject *mk,
 629                                      const struct kernel_param *kp,
 630                                      const char *name)
 631 {
 632         struct module_param_attrs *new_mp;
 633         struct attribute **new_attrs;
 634         unsigned int i;
 635
 636         /* We don't bother calling this with invisible parameters. */
 637         BUG_ON(!kp->perm);
 638
 639         if (!mk->mp) {
 640                 /* First allocation. */
 641                 mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL);
 642                 if (!mk->mp)
 643                         return -ENOMEM;
 644                 mk->mp->grp.name = "parameters";
 645                 /* NULL-terminated attribute array. */
 646                 mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]),
 647                                             GFP_KERNEL);
 648                 /* Caller will cleanup via free_module_param_attrs */
 649                 if (!mk->mp->grp.attrs)
 650                         return -ENOMEM;
 651         }
 652
 653         /* Enlarge allocations. */
 654         new_mp = krealloc(mk->mp,
 655                           sizeof(*mk->mp) +
 656                           sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1),
 657                           GFP_KERNEL);
 658         if (!new_mp)
 659                 return -ENOMEM;
 660         mk->mp = new_mp;
 661
 662         /* Extra pointer for NULL terminator */
 663         new_attrs = krealloc(mk->mp->grp.attrs,
 664                              sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2),
 665                              GFP_KERNEL);
 666         if (!new_attrs)
 667                 return -ENOMEM;
 668         mk->mp->grp.attrs = new_attrs;
 669
 670         /* Tack new one on the end. */
 671         memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0]));
 672         sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr);
 673         mk->mp->attrs[mk->mp->num].param = kp;
 674         mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show;
 675         /* Do not allow runtime DAC changes to make param writable. */
 676         if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0)
 677                 mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store;
 678         else
 679                 mk->mp->attrs[mk->mp->num].mattr.store = NULL;
 680         mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name;
 681         mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm;
 682         mk->mp->num++;
 683
 684         /* Fix up all the pointers, since krealloc can move us */
 685         for (i = 0; i < mk->mp->num; i++)
 686                 mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr;
 687         mk->mp->grp.attrs[mk->mp->num] = NULL;
 688         return 0;
 689 }
 690
 691 #ifdef CONFIG_MODULES
 692 static void free_module_param_attrs(struct module_kobject *mk)
 693 {
 694         if (mk->mp)
 695                 kfree(mk->mp->grp.attrs);
 696         kfree(mk->mp);
 697         mk->mp = NULL;
 698 }
 699
 700 /*
 701  * module_param_sysfs_setup - setup sysfs support for one module
 702  * @mod: module
 703  * @kparam: module parameters (array)
 704  * @num_params: number of module parameters
 705  *
 706  * Adds sysfs entries for module parameters under
 707  * /sys/module/[mod->name]/parameters/
 708  */
 709 int module_param_sysfs_setup(struct module *mod,
 710                              const struct kernel_param *kparam,
 711                              unsigned int num_params)
 712 {
 713         int i, err;
 714         bool params = false;
 715
 716         for (i = 0; i < num_params; i++) {
 717                 if (kparam[i].perm == 0)
 718                         continue;
 719                 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 720                 if (err) {
 721                         free_module_param_attrs(&mod->mkobj);
 722                         return err;
 723                 }
 724                 params = true;
 725         }
 726
 727         if (!params)
 728                 return 0;
 729
 730         /* Create the param group. */
 731         err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 732         if (err)
 733                 free_module_param_attrs(&mod->mkobj);
 734         return err;
 735 }
 736
 737 /*
 738  * module_param_sysfs_remove - remove sysfs support for one module
 739  * @mod: module
 740  *
 741  * Remove sysfs entries for module parameters and the corresponding
 742  * kobject.
 743  */
 744 void module_param_sysfs_remove(struct module *mod)
 745 {
 746         if (mod->mkobj.mp) {
 747                 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 748                 /*
 749                  * We are positive that no one is using any param
 750                  * attrs at this point. Deallocate immediately.
 751                  */
 752                 free_module_param_attrs(&mod->mkobj);
 753         }
 754 }
 755 #endif
 756
 757 void destroy_params(const struct kernel_param *params, unsigned num)
 758 {
 759         unsigned int i;
 760
 761         for (i = 0; i < num; i++)
 762                 if (params[i].ops->free)
 763                         params[i].ops->free(params[i].arg);
 764 }
 765
 766 static struct module_kobject * __init locate_module_kobject(const char *name)
 767 {
 768         struct module_kobject *mk;
 769         struct kobject *kobj;
 770         int err;
 771
 772         kobj = kset_find_obj(module_kset, name);
 773         if (kobj) {
 774                 mk = to_module_kobject(kobj);
 775         } else {
 776                 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 777                 BUG_ON(!mk);
 778
 779                 mk->mod = THIS_MODULE;
 780                 mk->kobj.kset = module_kset;
 781                 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 782                                            "%s", name);
 783 #ifdef CONFIG_MODULES
 784                 if (!err)
 785                         err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
 786 #endif
 787                 if (err) {
 788                         kobject_put(&mk->kobj);
 789                         pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
 790                                 name, err);
 791                         return NULL;
 792                 }
 793
 794                 /* So that we hold reference in both cases. */
 795                 kobject_get(&mk->kobj);
 796         }
 797
 798         return mk;
 799 }
 800
 801 static void __init kernel_add_sysfs_param(const char *name,
 802                                           const struct kernel_param *kparam,
 803                                           unsigned int name_skip)
 804 {
 805         struct module_kobject *mk;
 806         int err;
 807
 808         mk = locate_module_kobject(name);
 809         if (!mk)
 810                 return;
 811
 812         /* We need to remove old parameters before adding more. */
 813         if (mk->mp)
 814                 sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 815
 816         /* These should not fail at boot. */
 817         err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 818         BUG_ON(err);
 819         err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 820         BUG_ON(err);
 821         kobject_uevent(&mk->kobj, KOBJ_ADD);
 822         kobject_put(&mk->kobj);
 823 }
 824
 825 /*
 826  * param_sysfs_builtin - add sysfs parameters for built-in modules
 827  *
 828  * Add module_parameters to sysfs for "modules" built into the kernel.
 829  *
 830  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 831  * "parameter" name is stored behind a dot in kernel_param->name. So,
 832  * extract the "module" name for all built-in kernel_param-eters,
 833  * and for all who have the same, call kernel_add_sysfs_param.
 834  */
 835 static void __init param_sysfs_builtin(void)
 836 {
 837         const struct kernel_param *kp;
 838         unsigned int name_len;
 839         char modname[MODULE_NAME_LEN];
 840
 841         for (kp = __start___param; kp < __stop___param; kp++) {
 842                 char *dot;
 843
 844                 if (kp->perm == 0)
 845                         continue;
 846
 847                 dot = strchr(kp->name, '.');
 848                 if (!dot) {
 849                         /* This happens for core_param() */
 850                         strcpy(modname, "kernel");
 851                         name_len = 0;
 852                 } else {
 853                         name_len = dot - kp->name + 1;
 854                         strscpy(modname, kp->name, name_len);
 855                 }
 856                 kernel_add_sysfs_param(modname, kp, name_len);
 857         }
 858 }
 859
 860 ssize_t __modver_version_show(struct module_attribute *mattr,
 861                               struct module_kobject *mk, char *buf)
 862 {
 863         struct module_version_attribute *vattr =
 864                 container_of(mattr, struct module_version_attribute, mattr);
 865
 866         return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
 867 }
 868
 869 extern const struct module_version_attribute __start___modver[];
 870 extern const struct module_version_attribute __stop___modver[];
 871
 872 static void __init version_sysfs_builtin(void)
 873 {
 874         const struct module_version_attribute *vattr;
 875         struct module_kobject *mk;
 876         int err;
 877
 878         for (vattr = __start___modver; vattr < __stop___modver; vattr++) {
 879                 mk = locate_module_kobject(vattr->module_name);
 880                 if (mk) {
 881                         err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
 882                         WARN_ON_ONCE(err);
 883                         kobject_uevent(&mk->kobj, KOBJ_ADD);
 884                         kobject_put(&mk->kobj);
 885                 }
 886         }
 887 }
 888
 889 /* module-related sysfs stuff */
 890
 891 static ssize_t module_attr_show(struct kobject *kobj,
 892                                 struct attribute *attr,
 893                                 char *buf)
 894 {
 895         struct module_attribute *attribute;
 896         struct module_kobject *mk;
 897         int ret;
 898
 899         attribute = to_module_attr(attr);
 900         mk = to_module_kobject(kobj);
 901
 902         if (!attribute->show)
 903                 return -EIO;
 904
 905         ret = attribute->show(attribute, mk, buf);
 906
 907         return ret;
 908 }
 909
 910 static ssize_t module_attr_store(struct kobject *kobj,
 911                                 struct attribute *attr,
 912                                 const char *buf, size_t len)
 913 {
 914         struct module_attribute *attribute;
 915         struct module_kobject *mk;
 916         int ret;
 917
 918         attribute = to_module_attr(attr);
 919         mk = to_module_kobject(kobj);
 920
 921         if (!attribute->store)
 922                 return -EIO;
 923
 924         ret = attribute->store(attribute, mk, buf, len);
 925
 926         return ret;
 927 }
 928
 929 static const struct sysfs_ops module_sysfs_ops = {
 930         .show = module_attr_show,
 931         .store = module_attr_store,
 932 };
 933
 934 static int uevent_filter(const struct kobject *kobj)
 935 {
 936         const struct kobj_type *ktype = get_ktype(kobj);
 937
 938         if (ktype == &module_ktype)
 939                 return 1;
 940         return 0;
 941 }
 942
 943 static const struct kset_uevent_ops module_uevent_ops = {
 944         .filter = uevent_filter,
 945 };
 946
 947 struct kset *module_kset;
 948
 949 static void module_kobj_release(struct kobject *kobj)
 950 {
 951         struct module_kobject *mk = to_module_kobject(kobj);
 952         complete(mk->kobj_completion);
 953 }
 954
 955 const struct kobj_type module_ktype = {
 956         .release   =    module_kobj_release,
 957         .sysfs_ops =    &module_sysfs_ops,
 958 };
 959
 960 /*
 961  * param_sysfs_init - create "module" kset
 962  *
 963  * This must be done before the initramfs is unpacked and
 964  * request_module() thus becomes possible, because otherwise the
 965  * module load would fail in mod_sysfs_init.
 966  */
 967 static int __init param_sysfs_init(void)
 968 {
 969         module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
 970         if (!module_kset) {
 971                 printk(KERN_WARNING "%s (%d): error creating kset\n",
 972                         __FILE__, __LINE__);
 973                 return -ENOMEM;
 974         }
 975
 976         return 0;
 977 }
 978 subsys_initcall(param_sysfs_init);
 979
 980 /*
 981  * param_sysfs_builtin_init - add sysfs version and parameter
 982  * attributes for built-in modules
 983  */
 984 static int __init param_sysfs_builtin_init(void)
 985 {
 986         if (!module_kset)
 987                 return -ENOMEM;
 988
 989         version_sysfs_builtin();
 990         param_sysfs_builtin();
 991
 992         return 0;
 993 }
 994 late_initcall(param_sysfs_builtin_init);
 995
 996 #endif /* CONFIG_SYSFS */