kernel/params.c

   1 /* Helpers for initial module or kernel cmdline parsing
   2    Copyright (C) 2001 Rusty Russell.
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17 */
  18 #include <linux/kernel.h>
  19 #include <linux/string.h>
  20 #include <linux/errno.h>
  21 #include <linux/module.h>
  22 #include <linux/moduleparam.h>
  23 #include <linux/device.h>
  24 #include <linux/err.h>
  25 #include <linux/slab.h>
  26 #include <linux/ctype.h>
  27
  28 /* Protects all parameters, and incidentally kmalloced_param list. */
  29 static DEFINE_MUTEX(param_lock);
  30
  31 /* This just allows us to keep track of which parameters are kmalloced. */
  32 struct kmalloced_param {
  33         struct list_head list;
  34         char val[];
  35 };
  36 static LIST_HEAD(kmalloced_params);
  37
  38 static void *kmalloc_parameter(unsigned int size)
  39 {
  40         struct kmalloced_param *p;
  41
  42         p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
  43         if (!p)
  44                 return NULL;
  45
  46         list_add(&p->list, &kmalloced_params);
  47         return p->val;
  48 }
  49
  50 /* Does nothing if parameter wasn't kmalloced above. */
  51 static void maybe_kfree_parameter(void *param)
  52 {
  53         struct kmalloced_param *p;
  54
  55         list_for_each_entry(p, &kmalloced_params, list) {
  56                 if (p->val == param) {
  57                         list_del(&p->list);
  58                         kfree(p);
  59                         break;
  60                 }
  61         }
  62 }
  63
  64 static char dash2underscore(char c)
  65 {
  66         if (c == '-')
  67                 return '_';
  68         return c;
  69 }
  70
  71 bool parameqn(const char *a, const char *b, size_t n)
  72 {
  73         size_t i;
  74
  75         for (i = 0; i < n; i++) {
  76                 if (dash2underscore(a[i]) != dash2underscore(b[i]))
  77                         return false;
  78         }
  79         return true;
  80 }
  81
  82 bool parameq(const char *a, const char *b)
  83 {
  84         return parameqn(a, b, strlen(a)+1);
  85 }
  86
  87 static void param_check_unsafe(const struct kernel_param *kp)
  88 {
  89         if (kp->flags & KERNEL_PARAM_FL_UNSAFE) {
  90                 pr_warn("Setting dangerous option %s - tainting kernel\n",
  91                         kp->name);
  92                 add_taint(TAINT_USER, LOCKDEP_STILL_OK);
  93         }
  94 }
  95
  96 static int parse_one(char *param,
  97                      char *val,
  98                      const char *doing,
  99                      const struct kernel_param *params,
 100                      unsigned num_params,
 101                      s16 min_level,
 102                      s16 max_level,
 103                      int (*handle_unknown)(char *param, char *val,
 104                                      const char *doing))
 105 {
 106         unsigned int i;
 107         int err;
 108
 109         /* Find parameter */
 110         for (i = 0; i < num_params; i++) {
 111                 if (parameq(param, params[i].name)) {
 112                         if (params[i].level < min_level
 113                             || params[i].level > max_level)
 114                                 return 0;
 115                         /* No one handled NULL, so do it here. */
 116                         if (!val &&
 117                             !(params[i].ops->flags & KERNEL_PARAM_OPS_FL_NOARG))
 118                                 return -EINVAL;
 119                         pr_debug("handling %s with %p\n", param,
 120                                 params[i].ops->set);
 121                         mutex_lock(&param_lock);
 122                         param_check_unsafe(&params[i]);
 123                         err = params[i].ops->set(val, &params[i]);
 124                         mutex_unlock(&param_lock);
 125                         return err;
 126                 }
 127         }
 128
 129         if (handle_unknown) {
 130                 pr_debug("doing %s: %s='%s'\n", doing, param, val);
 131                 return handle_unknown(param, val, doing);
 132         }
 133
 134         pr_debug("Unknown argument '%s'\n", param);
 135         return -ENOENT;
 136 }
 137
 138 /* You can use " around spaces, but can't escape ". */
 139 /* Hyphens and underscores equivalent in parameter names. */
 140 static char *next_arg(char *args, char **param, char **val)
 141 {
 142         unsigned int i, equals = 0;
 143         int in_quote = 0, quoted = 0;
 144         char *next;
 145
 146         if (*args == '"') {
 147                 args++;
 148                 in_quote = 1;
 149                 quoted = 1;
 150         }
 151
 152         for (i = 0; args[i]; i++) {
 153                 if (isspace(args[i]) && !in_quote)
 154                         break;
 155                 if (equals == 0) {
 156                         if (args[i] == '=')
 157                                 equals = i;
 158                 }
 159                 if (args[i] == '"')
 160                         in_quote = !in_quote;
 161         }
 162
 163         *param = args;
 164         if (!equals)
 165                 *val = NULL;
 166         else {
 167                 args[equals] = '\0';
 168                 *val = args + equals + 1;
 169
 170                 /* Don't include quotes in value. */
 171                 if (**val == '"') {
 172                         (*val)++;
 173                         if (args[i-1] == '"')
 174                                 args[i-1] = '\0';
 175                 }
 176         }
 177         if (quoted && args[i-1] == '"')
 178                 args[i-1] = '\0';
 179
 180         if (args[i]) {
 181                 args[i] = '\0';
 182                 next = args + i + 1;
 183         } else
 184                 next = args + i;
 185
 186         /* Chew up trailing spaces. */
 187         return skip_spaces(next);
 188 }
 189
 190 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 191 char *parse_args(const char *doing,
 192                  char *args,
 193                  const struct kernel_param *params,
 194                  unsigned num,
 195                  s16 min_level,
 196                  s16 max_level,
 197                  int (*unknown)(char *param, char *val, const char *doing))
 198 {
 199         char *param, *val;
 200
 201         /* Chew leading spaces */
 202         args = skip_spaces(args);
 203
 204         if (*args)
 205                 pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
 206
 207         while (*args) {
 208                 int ret;
 209                 int irq_was_disabled;
 210
 211                 args = next_arg(args, &param, &val);
 212                 /* Stop at -- */
 213                 if (!val && strcmp(param, "--") == 0)
 214                         return args;
 215                 irq_was_disabled = irqs_disabled();
 216                 ret = parse_one(param, val, doing, params, num,
 217                                 min_level, max_level, unknown);
 218                 if (irq_was_disabled && !irqs_disabled())
 219                         pr_warn("%s: option '%s' enabled irq's!\n",
 220                                 doing, param);
 221
 222                 switch (ret) {
 223                 case -ENOENT:
 224                         pr_err("%s: Unknown parameter `%s'\n", doing, param);
 225                         return ERR_PTR(ret);
 226                 case -ENOSPC:
 227                         pr_err("%s: `%s' too large for parameter `%s'\n",
 228                                doing, val ?: "", param);
 229                         return ERR_PTR(ret);
 230                 case 0:
 231                         break;
 232                 default:
 233                         pr_err("%s: `%s' invalid for parameter `%s'\n",
 234                                doing, val ?: "", param);
 235                         return ERR_PTR(ret);
 236                 }
 237         }
 238
 239         /* All parsed OK. */
 240         return NULL;
 241 }
 242
 243 /* Lazy bastard, eh? */
 244 #define STANDARD_PARAM_DEF(name, type, format, strtolfn)                \
 245         int param_set_##name(const char *val, const struct kernel_param *kp) \
 246         {                                                               \
 247                 return strtolfn(val, 0, (type *)kp->arg);               \
 248         }                                                               \
 249         int param_get_##name(char *buffer, const struct kernel_param *kp) \
 250         {                                                               \
 251                 return scnprintf(buffer, PAGE_SIZE, format,             \
 252                                 *((type *)kp->arg));                    \
 253         }                                                               \
 254         const struct kernel_param_ops param_ops_##name = {                      \
 255                 .set = param_set_##name,                                \
 256                 .get = param_get_##name,                                \
 257         };                                                              \
 258         EXPORT_SYMBOL(param_set_##name);                                \
 259         EXPORT_SYMBOL(param_get_##name);                                \
 260         EXPORT_SYMBOL(param_ops_##name)
 261
 262
 263 STANDARD_PARAM_DEF(byte, unsigned char, "%hhu", kstrtou8);
 264 STANDARD_PARAM_DEF(short, short, "%hi", kstrtos16);
 265 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", kstrtou16);
 266 STANDARD_PARAM_DEF(int, int, "%i", kstrtoint);
 267 STANDARD_PARAM_DEF(uint, unsigned int, "%u", kstrtouint);
 268 STANDARD_PARAM_DEF(long, long, "%li", kstrtol);
 269 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", kstrtoul);
 270 STANDARD_PARAM_DEF(ullong, unsigned long long, "%llu", kstrtoull);
 271
 272 int param_set_charp(const char *val, const struct kernel_param *kp)
 273 {
 274         if (strlen(val) > 1024) {
 275                 pr_err("%s: string parameter too long\n", kp->name);
 276                 return -ENOSPC;
 277         }
 278
 279         maybe_kfree_parameter(*(char **)kp->arg);
 280
 281         /* This is a hack.  We can't kmalloc in early boot, and we
 282          * don't need to; this mangled commandline is preserved. */
 283         if (slab_is_available()) {
 284                 *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
 285                 if (!*(char **)kp->arg)
 286                         return -ENOMEM;
 287                 strcpy(*(char **)kp->arg, val);
 288         } else
 289                 *(const char **)kp->arg = val;
 290
 291         return 0;
 292 }
 293 EXPORT_SYMBOL(param_set_charp);
 294
 295 int param_get_charp(char *buffer, const struct kernel_param *kp)
 296 {
 297         return scnprintf(buffer, PAGE_SIZE, "%s", *((char **)kp->arg));
 298 }
 299 EXPORT_SYMBOL(param_get_charp);
 300
 301 static void param_free_charp(void *arg)
 302 {
 303         maybe_kfree_parameter(*((char **)arg));
 304 }
 305
 306 const struct kernel_param_ops param_ops_charp = {
 307         .set = param_set_charp,
 308         .get = param_get_charp,
 309         .free = param_free_charp,
 310 };
 311 EXPORT_SYMBOL(param_ops_charp);
 312
 313 /* Actually could be a bool or an int, for historical reasons. */
 314 int param_set_bool(const char *val, const struct kernel_param *kp)
 315 {
 316         /* No equals means "set"... */
 317         if (!val) val = "1";
 318
 319         /* One of =[yYnN01] */
 320         return strtobool(val, kp->arg);
 321 }
 322 EXPORT_SYMBOL(param_set_bool);
 323
 324 int param_get_bool(char *buffer, const struct kernel_param *kp)
 325 {
 326         /* Y and N chosen as being relatively non-coder friendly */
 327         return sprintf(buffer, "%c", *(bool *)kp->arg ? 'Y' : 'N');
 328 }
 329 EXPORT_SYMBOL(param_get_bool);
 330
 331 const struct kernel_param_ops param_ops_bool = {
 332         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 333         .set = param_set_bool,
 334         .get = param_get_bool,
 335 };
 336 EXPORT_SYMBOL(param_ops_bool);
 337
 338 int param_set_bool_enable_only(const char *val, const struct kernel_param *kp)
 339 {
 340         int err = 0;
 341         bool new_value;
 342         bool orig_value = *(bool *)kp->arg;
 343         struct kernel_param dummy_kp = *kp;
 344
 345         dummy_kp.arg = &new_value;
 346
 347         err = param_set_bool(val, &dummy_kp);
 348         if (err)
 349                 return err;
 350
 351         /* Don't let them unset it once it's set! */
 352         if (!new_value && orig_value)
 353                 return -EROFS;
 354
 355         if (new_value)
 356                 err = param_set_bool(val, kp);
 357
 358         return err;
 359 }
 360 EXPORT_SYMBOL_GPL(param_set_bool_enable_only);
 361
 362 const struct kernel_param_ops param_ops_bool_enable_only = {
 363         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 364         .set = param_set_bool_enable_only,
 365         .get = param_get_bool,
 366 };
 367
 368 /* This one must be bool. */
 369 int param_set_invbool(const char *val, const struct kernel_param *kp)
 370 {
 371         int ret;
 372         bool boolval;
 373         struct kernel_param dummy;
 374
 375         dummy.arg = &boolval;
 376         ret = param_set_bool(val, &dummy);
 377         if (ret == 0)
 378                 *(bool *)kp->arg = !boolval;
 379         return ret;
 380 }
 381 EXPORT_SYMBOL(param_set_invbool);
 382
 383 int param_get_invbool(char *buffer, const struct kernel_param *kp)
 384 {
 385         return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
 386 }
 387 EXPORT_SYMBOL(param_get_invbool);
 388
 389 const struct kernel_param_ops param_ops_invbool = {
 390         .set = param_set_invbool,
 391         .get = param_get_invbool,
 392 };
 393 EXPORT_SYMBOL(param_ops_invbool);
 394
 395 int param_set_bint(const char *val, const struct kernel_param *kp)
 396 {
 397         struct kernel_param boolkp;
 398         bool v;
 399         int ret;
 400
 401         /* Match bool exactly, by re-using it. */
 402         boolkp = *kp;
 403         boolkp.arg = &v;
 404
 405         ret = param_set_bool(val, &boolkp);
 406         if (ret == 0)
 407                 *(int *)kp->arg = v;
 408         return ret;
 409 }
 410 EXPORT_SYMBOL(param_set_bint);
 411
 412 const struct kernel_param_ops param_ops_bint = {
 413         .flags = KERNEL_PARAM_OPS_FL_NOARG,
 414         .set = param_set_bint,
 415         .get = param_get_int,
 416 };
 417 EXPORT_SYMBOL(param_ops_bint);
 418
 419 /* We break the rule and mangle the string. */
 420 static int param_array(const char *name,
 421                        const char *val,
 422                        unsigned int min, unsigned int max,
 423                        void *elem, int elemsize,
 424                        int (*set)(const char *, const struct kernel_param *kp),
 425                        s16 level,
 426                        unsigned int *num)
 427 {
 428         int ret;
 429         struct kernel_param kp;
 430         char save;
 431
 432         /* Get the name right for errors. */
 433         kp.name = name;
 434         kp.arg = elem;
 435         kp.level = level;
 436
 437         *num = 0;
 438         /* We expect a comma-separated list of values. */
 439         do {
 440                 int len;
 441
 442                 if (*num == max) {
 443                         pr_err("%s: can only take %i arguments\n", name, max);
 444                         return -EINVAL;
 445                 }
 446                 len = strcspn(val, ",");
 447
 448                 /* nul-terminate and parse */
 449                 save = val[len];
 450                 ((char *)val)[len] = '\0';
 451                 BUG_ON(!mutex_is_locked(&param_lock));
 452                 ret = set(val, &kp);
 453
 454                 if (ret != 0)
 455                         return ret;
 456                 kp.arg += elemsize;
 457                 val += len+1;
 458                 (*num)++;
 459         } while (save == ',');
 460
 461         if (*num < min) {
 462                 pr_err("%s: needs at least %i arguments\n", name, min);
 463                 return -EINVAL;
 464         }
 465         return 0;
 466 }
 467
 468 static int param_array_set(const char *val, const struct kernel_param *kp)
 469 {
 470         const struct kparam_array *arr = kp->arr;
 471         unsigned int temp_num;
 472
 473         return param_array(kp->name, val, 1, arr->max, arr->elem,
 474                            arr->elemsize, arr->ops->set, kp->level,
 475                            arr->num ?: &temp_num);
 476 }
 477
 478 static int param_array_get(char *buffer, const struct kernel_param *kp)
 479 {
 480         int i, off, ret;
 481         const struct kparam_array *arr = kp->arr;
 482         struct kernel_param p;
 483
 484         p = *kp;
 485         for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 486                 if (i)
 487                         buffer[off++] = ',';
 488                 p.arg = arr->elem + arr->elemsize * i;
 489                 BUG_ON(!mutex_is_locked(&param_lock));
 490                 ret = arr->ops->get(buffer + off, &p);
 491                 if (ret < 0)
 492                         return ret;
 493                 off += ret;
 494         }
 495         buffer[off] = '\0';
 496         return off;
 497 }
 498
 499 static void param_array_free(void *arg)
 500 {
 501         unsigned int i;
 502         const struct kparam_array *arr = arg;
 503
 504         if (arr->ops->free)
 505                 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 506                         arr->ops->free(arr->elem + arr->elemsize * i);
 507 }
 508
 509 const struct kernel_param_ops param_array_ops = {
 510         .set = param_array_set,
 511         .get = param_array_get,
 512         .free = param_array_free,
 513 };
 514 EXPORT_SYMBOL(param_array_ops);
 515
 516 int param_set_copystring(const char *val, const struct kernel_param *kp)
 517 {
 518         const struct kparam_string *kps = kp->str;
 519
 520         if (strlen(val)+1 > kps->maxlen) {
 521                 pr_err("%s: string doesn't fit in %u chars.\n",
 522                        kp->name, kps->maxlen-1);
 523                 return -ENOSPC;
 524         }
 525         strcpy(kps->string, val);
 526         return 0;
 527 }
 528 EXPORT_SYMBOL(param_set_copystring);
 529
 530 int param_get_string(char *buffer, const struct kernel_param *kp)
 531 {
 532         const struct kparam_string *kps = kp->str;
 533         return strlcpy(buffer, kps->string, kps->maxlen);
 534 }
 535 EXPORT_SYMBOL(param_get_string);
 536
 537 const struct kernel_param_ops param_ops_string = {
 538         .set = param_set_copystring,
 539         .get = param_get_string,
 540 };
 541 EXPORT_SYMBOL(param_ops_string);
 542
 543 /* sysfs output in /sys/modules/XYZ/parameters/ */
 544 #define to_module_attr(n) container_of(n, struct module_attribute, attr)
 545 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 546
 547 struct param_attribute
 548 {
 549         struct module_attribute mattr;
 550         const struct kernel_param *param;
 551 };
 552
 553 struct module_param_attrs
 554 {
 555         unsigned int num;
 556         struct attribute_group grp;
 557         struct param_attribute attrs[0];
 558 };
 559
 560 #ifdef CONFIG_SYSFS
 561 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 562
 563 static ssize_t param_attr_show(struct module_attribute *mattr,
 564                                struct module_kobject *mk, char *buf)
 565 {
 566         int count;
 567         struct param_attribute *attribute = to_param_attr(mattr);
 568
 569         if (!attribute->param->ops->get)
 570                 return -EPERM;
 571
 572         mutex_lock(&param_lock);
 573         count = attribute->param->ops->get(buf, attribute->param);
 574         mutex_unlock(&param_lock);
 575         if (count > 0) {
 576                 strcat(buf, "\n");
 577                 ++count;
 578         }
 579         return count;
 580 }
 581
 582 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 583 static ssize_t param_attr_store(struct module_attribute *mattr,
 584                                 struct module_kobject *km,
 585                                 const char *buf, size_t len)
 586 {
 587         int err;
 588         struct param_attribute *attribute = to_param_attr(mattr);
 589
 590         if (!attribute->param->ops->set)
 591                 return -EPERM;
 592
 593         mutex_lock(&param_lock);
 594         param_check_unsafe(attribute->param);
 595         err = attribute->param->ops->set(buf, attribute->param);
 596         mutex_unlock(&param_lock);
 597         if (!err)
 598                 return len;
 599         return err;
 600 }
 601 #endif
 602
 603 #ifdef CONFIG_MODULES
 604 #define __modinit
 605 #else
 606 #define __modinit __init
 607 #endif
 608
 609 #ifdef CONFIG_SYSFS
 610 void __kernel_param_lock(void)
 611 {
 612         mutex_lock(&param_lock);
 613 }
 614 EXPORT_SYMBOL(__kernel_param_lock);
 615
 616 void __kernel_param_unlock(void)
 617 {
 618         mutex_unlock(&param_lock);
 619 }
 620 EXPORT_SYMBOL(__kernel_param_unlock);
 621
 622 /*
 623  * add_sysfs_param - add a parameter to sysfs
 624  * @mk: struct module_kobject
 625  * @kparam: the actual parameter definition to add to sysfs
 626  * @name: name of parameter
 627  *
 628  * Create a kobject if for a (per-module) parameter if mp NULL, and
 629  * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 630  * if there's an error.
 631  */
 632 static __modinit int add_sysfs_param(struct module_kobject *mk,
 633                                      const struct kernel_param *kp,
 634                                      const char *name)
 635 {
 636         struct module_param_attrs *new_mp;
 637         struct attribute **new_attrs;
 638         unsigned int i;
 639
 640         /* We don't bother calling this with invisible parameters. */
 641         BUG_ON(!kp->perm);
 642
 643         if (!mk->mp) {
 644                 /* First allocation. */
 645                 mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL);
 646                 if (!mk->mp)
 647                         return -ENOMEM;
 648                 mk->mp->grp.name = "parameters";
 649                 /* NULL-terminated attribute array. */
 650                 mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]),
 651                                             GFP_KERNEL);
 652                 /* Caller will cleanup via free_module_param_attrs */
 653                 if (!mk->mp->grp.attrs)
 654                         return -ENOMEM;
 655         }
 656
 657         /* Enlarge allocations. */
 658         new_mp = krealloc(mk->mp,
 659                           sizeof(*mk->mp) +
 660                           sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1),
 661                           GFP_KERNEL);
 662         if (!new_mp)
 663                 return -ENOMEM;
 664         mk->mp = new_mp;
 665
 666         /* Extra pointer for NULL terminator */
 667         new_attrs = krealloc(mk->mp->grp.attrs,
 668                              sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2),
 669                              GFP_KERNEL);
 670         if (!new_attrs)
 671                 return -ENOMEM;
 672         mk->mp->grp.attrs = new_attrs;
 673
 674         /* Tack new one on the end. */
 675         memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0]));
 676         sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr);
 677         mk->mp->attrs[mk->mp->num].param = kp;
 678         mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show;
 679         /* Do not allow runtime DAC changes to make param writable. */
 680         if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0)
 681                 mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store;
 682         else
 683                 mk->mp->attrs[mk->mp->num].mattr.store = NULL;
 684         mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name;
 685         mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm;
 686         mk->mp->num++;
 687
 688         /* Fix up all the pointers, since krealloc can move us */
 689         for (i = 0; i < mk->mp->num; i++)
 690                 mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr;
 691         mk->mp->grp.attrs[mk->mp->num] = NULL;
 692         return 0;
 693 }
 694
 695 #ifdef CONFIG_MODULES
 696 static void free_module_param_attrs(struct module_kobject *mk)
 697 {
 698         if (mk->mp)
 699                 kfree(mk->mp->grp.attrs);
 700         kfree(mk->mp);
 701         mk->mp = NULL;
 702 }
 703
 704 /*
 705  * module_param_sysfs_setup - setup sysfs support for one module
 706  * @mod: module
 707  * @kparam: module parameters (array)
 708  * @num_params: number of module parameters
 709  *
 710  * Adds sysfs entries for module parameters under
 711  * /sys/module/[mod->name]/parameters/
 712  */
 713 int module_param_sysfs_setup(struct module *mod,
 714                              const struct kernel_param *kparam,
 715                              unsigned int num_params)
 716 {
 717         int i, err;
 718         bool params = false;
 719
 720         for (i = 0; i < num_params; i++) {
 721                 if (kparam[i].perm == 0)
 722                         continue;
 723                 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 724                 if (err) {
 725                         free_module_param_attrs(&mod->mkobj);
 726                         return err;
 727                 }
 728                 params = true;
 729         }
 730
 731         if (!params)
 732                 return 0;
 733
 734         /* Create the param group. */
 735         err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 736         if (err)
 737                 free_module_param_attrs(&mod->mkobj);
 738         return err;
 739 }
 740
 741 /*
 742  * module_param_sysfs_remove - remove sysfs support for one module
 743  * @mod: module
 744  *
 745  * Remove sysfs entries for module parameters and the corresponding
 746  * kobject.
 747  */
 748 void module_param_sysfs_remove(struct module *mod)
 749 {
 750         if (mod->mkobj.mp) {
 751                 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 752                 /* We are positive that no one is using any param
 753                  * attrs at this point.  Deallocate immediately. */
 754                 free_module_param_attrs(&mod->mkobj);
 755         }
 756 }
 757 #endif
 758
 759 void destroy_params(const struct kernel_param *params, unsigned num)
 760 {
 761         unsigned int i;
 762
 763         for (i = 0; i < num; i++)
 764                 if (params[i].ops->free)
 765                         params[i].ops->free(params[i].arg);
 766 }
 767
 768 static struct module_kobject * __init locate_module_kobject(const char *name)
 769 {
 770         struct module_kobject *mk;
 771         struct kobject *kobj;
 772         int err;
 773
 774         kobj = kset_find_obj(module_kset, name);
 775         if (kobj) {
 776                 mk = to_module_kobject(kobj);
 777         } else {
 778                 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 779                 BUG_ON(!mk);
 780
 781                 mk->mod = THIS_MODULE;
 782                 mk->kobj.kset = module_kset;
 783                 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 784                                            "%s", name);
 785 #ifdef CONFIG_MODULES
 786                 if (!err)
 787                         err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
 788 #endif
 789                 if (err) {
 790                         kobject_put(&mk->kobj);
 791                         pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",
 792                                 name, err);
 793                         return NULL;
 794                 }
 795
 796                 /* So that we hold reference in both cases. */
 797                 kobject_get(&mk->kobj);
 798         }
 799
 800         return mk;
 801 }
 802
 803 static void __init kernel_add_sysfs_param(const char *name,
 804                                           const struct kernel_param *kparam,
 805                                           unsigned int name_skip)
 806 {
 807         struct module_kobject *mk;
 808         int err;
 809
 810         mk = locate_module_kobject(name);
 811         if (!mk)
 812                 return;
 813
 814         /* We need to remove old parameters before adding more. */
 815         if (mk->mp)
 816                 sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 817
 818         /* These should not fail at boot. */
 819         err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 820         BUG_ON(err);
 821         err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 822         BUG_ON(err);
 823         kobject_uevent(&mk->kobj, KOBJ_ADD);
 824         kobject_put(&mk->kobj);
 825 }
 826
 827 /*
 828  * param_sysfs_builtin - add sysfs parameters for built-in modules
 829  *
 830  * Add module_parameters to sysfs for "modules" built into the kernel.
 831  *
 832  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 833  * "parameter" name is stored behind a dot in kernel_param->name. So,
 834  * extract the "module" name for all built-in kernel_param-eters,
 835  * and for all who have the same, call kernel_add_sysfs_param.
 836  */
 837 static void __init param_sysfs_builtin(void)
 838 {
 839         const struct kernel_param *kp;
 840         unsigned int name_len;
 841         char modname[MODULE_NAME_LEN];
 842
 843         for (kp = __start___param; kp < __stop___param; kp++) {
 844                 char *dot;
 845
 846                 if (kp->perm == 0)
 847                         continue;
 848
 849                 dot = strchr(kp->name, '.');
 850                 if (!dot) {
 851                         /* This happens for core_param() */
 852                         strcpy(modname, "kernel");
 853                         name_len = 0;
 854                 } else {
 855                         name_len = dot - kp->name + 1;
 856                         strlcpy(modname, kp->name, name_len);
 857                 }
 858                 kernel_add_sysfs_param(modname, kp, name_len);
 859         }
 860 }
 861
 862 ssize_t __modver_version_show(struct module_attribute *mattr,
 863                               struct module_kobject *mk, char *buf)
 864 {
 865         struct module_version_attribute *vattr =
 866                 container_of(mattr, struct module_version_attribute, mattr);
 867
 868         return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version);
 869 }
 870
 871 extern const struct module_version_attribute *__start___modver[];
 872 extern const struct module_version_attribute *__stop___modver[];
 873
 874 static void __init version_sysfs_builtin(void)
 875 {
 876         const struct module_version_attribute **p;
 877         struct module_kobject *mk;
 878         int err;
 879
 880         for (p = __start___modver; p < __stop___modver; p++) {
 881                 const struct module_version_attribute *vattr = *p;
 882
 883                 mk = locate_module_kobject(vattr->module_name);
 884                 if (mk) {
 885                         err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
 886                         kobject_uevent(&mk->kobj, KOBJ_ADD);
 887                         kobject_put(&mk->kobj);
 888                 }
 889         }
 890 }
 891
 892 /* module-related sysfs stuff */
 893
 894 static ssize_t module_attr_show(struct kobject *kobj,
 895                                 struct attribute *attr,
 896                                 char *buf)
 897 {
 898         struct module_attribute *attribute;
 899         struct module_kobject *mk;
 900         int ret;
 901
 902         attribute = to_module_attr(attr);
 903         mk = to_module_kobject(kobj);
 904
 905         if (!attribute->show)
 906                 return -EIO;
 907
 908         ret = attribute->show(attribute, mk, buf);
 909
 910         return ret;
 911 }
 912
 913 static ssize_t module_attr_store(struct kobject *kobj,
 914                                 struct attribute *attr,
 915                                 const char *buf, size_t len)
 916 {
 917         struct module_attribute *attribute;
 918         struct module_kobject *mk;
 919         int ret;
 920
 921         attribute = to_module_attr(attr);
 922         mk = to_module_kobject(kobj);
 923
 924         if (!attribute->store)
 925                 return -EIO;
 926
 927         ret = attribute->store(attribute, mk, buf, len);
 928
 929         return ret;
 930 }
 931
 932 static const struct sysfs_ops module_sysfs_ops = {
 933         .show = module_attr_show,
 934         .store = module_attr_store,
 935 };
 936
 937 static int uevent_filter(struct kset *kset, struct kobject *kobj)
 938 {
 939         struct kobj_type *ktype = get_ktype(kobj);
 940
 941         if (ktype == &module_ktype)
 942                 return 1;
 943         return 0;
 944 }
 945
 946 static const struct kset_uevent_ops module_uevent_ops = {
 947         .filter = uevent_filter,
 948 };
 949
 950 struct kset *module_kset;
 951 int module_sysfs_initialized;
 952
 953 static void module_kobj_release(struct kobject *kobj)
 954 {
 955         struct module_kobject *mk = to_module_kobject(kobj);
 956         complete(mk->kobj_completion);
 957 }
 958
 959 struct kobj_type module_ktype = {
 960         .release   =    module_kobj_release,
 961         .sysfs_ops =    &module_sysfs_ops,
 962 };
 963
 964 /*
 965  * param_sysfs_init - wrapper for built-in params support
 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         module_sysfs_initialized = 1;
 976
 977         version_sysfs_builtin();
 978         param_sysfs_builtin();
 979
 980         return 0;
 981 }
 982 subsys_initcall(param_sysfs_init);
 983
 984 #endif /* CONFIG_SYSFS */