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/moduleparam.h>
  19 #include <linux/kernel.h>
  20 #include <linux/string.h>
  21 #include <linux/errno.h>
  22 #include <linux/module.h>
  23 #include <linux/device.h>
  24 #include <linux/err.h>
  25 #include <linux/slab.h>
  26 #include <linux/ctype.h>
  27
  28 #if 0
  29 #define DEBUGP printk
  30 #else
  31 #define DEBUGP(fmt, a...)
  32 #endif
  33
  34 /* Protects all parameters, and incidentally kmalloced_param list. */
  35 static DEFINE_MUTEX(param_lock);
  36
  37 /* This just allows us to keep track of which parameters are kmalloced. */
  38 struct kmalloced_param {
  39         struct list_head list;
  40         char val[];
  41 };
  42 static LIST_HEAD(kmalloced_params);
  43
  44 static void *kmalloc_parameter(unsigned int size)
  45 {
  46         struct kmalloced_param *p;
  47
  48         p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
  49         if (!p)
  50                 return NULL;
  51
  52         list_add(&p->list, &kmalloced_params);
  53         return p->val;
  54 }
  55
  56 /* Does nothing if parameter wasn't kmalloced above. */
  57 static void maybe_kfree_parameter(void *param)
  58 {
  59         struct kmalloced_param *p;
  60
  61         list_for_each_entry(p, &kmalloced_params, list) {
  62                 if (p->val == param) {
  63                         list_del(&p->list);
  64                         kfree(p);
  65                         break;
  66                 }
  67         }
  68 }
  69
  70 static char dash2underscore(char c)
  71 {
  72         if (c == '-')
  73                 return '_';
  74         return c;
  75 }
  76
  77 bool parameqn(const char *a, const char *b, size_t n)
  78 {
  79         size_t i;
  80
  81         for (i = 0; i < n; i++) {
  82                 if (dash2underscore(a[i]) != dash2underscore(b[i]))
  83                         return false;
  84         }
  85         return true;
  86 }
  87
  88 bool parameq(const char *a, const char *b)
  89 {
  90         return parameqn(a, b, strlen(a)+1);
  91 }
  92
  93 static int parse_one(char *param,
  94                      char *val,
  95                      const struct kernel_param *params,
  96                      unsigned num_params,
  97                      int (*handle_unknown)(char *param, char *val))
  98 {
  99         unsigned int i;
 100         int err;
 101
 102         /* Find parameter */
 103         for (i = 0; i < num_params; i++) {
 104                 if (parameq(param, params[i].name)) {
 105                         /* No one handled NULL, so do it here. */
 106                         if (!val && params[i].ops->set != param_set_bool)
 107                                 return -EINVAL;
 108                         DEBUGP("They are equal!  Calling %p\n",
 109                                params[i].ops->set);
 110                         mutex_lock(&param_lock);
 111                         err = params[i].ops->set(val, &params[i]);
 112                         mutex_unlock(&param_lock);
 113                         return err;
 114                 }
 115         }
 116
 117         if (handle_unknown) {
 118                 DEBUGP("Unknown argument: calling %p\n", handle_unknown);
 119                 return handle_unknown(param, val);
 120         }
 121
 122         DEBUGP("Unknown argument `%s'\n", param);
 123         return -ENOENT;
 124 }
 125
 126 /* You can use " around spaces, but can't escape ". */
 127 /* Hyphens and underscores equivalent in parameter names. */
 128 static char *next_arg(char *args, char **param, char **val)
 129 {
 130         unsigned int i, equals = 0;
 131         int in_quote = 0, quoted = 0;
 132         char *next;
 133
 134         if (*args == '"') {
 135                 args++;
 136                 in_quote = 1;
 137                 quoted = 1;
 138         }
 139
 140         for (i = 0; args[i]; i++) {
 141                 if (isspace(args[i]) && !in_quote)
 142                         break;
 143                 if (equals == 0) {
 144                         if (args[i] == '=')
 145                                 equals = i;
 146                 }
 147                 if (args[i] == '"')
 148                         in_quote = !in_quote;
 149         }
 150
 151         *param = args;
 152         if (!equals)
 153                 *val = NULL;
 154         else {
 155                 args[equals] = '\0';
 156                 *val = args + equals + 1;
 157
 158                 /* Don't include quotes in value. */
 159                 if (**val == '"') {
 160                         (*val)++;
 161                         if (args[i-1] == '"')
 162                                 args[i-1] = '\0';
 163                 }
 164                 if (quoted && args[i-1] == '"')
 165                         args[i-1] = '\0';
 166         }
 167
 168         if (args[i]) {
 169                 args[i] = '\0';
 170                 next = args + i + 1;
 171         } else
 172                 next = args + i;
 173
 174         /* Chew up trailing spaces. */
 175         return skip_spaces(next);
 176 }
 177
 178 /* Args looks like "foo=bar,bar2 baz=fuz wiz". */
 179 int parse_args(const char *name,
 180                char *args,
 181                const struct kernel_param *params,
 182                unsigned num,
 183                int (*unknown)(char *param, char *val))
 184 {
 185         char *param, *val;
 186
 187         DEBUGP("Parsing ARGS: %s\n", args);
 188
 189         /* Chew leading spaces */
 190         args = skip_spaces(args);
 191
 192         while (*args) {
 193                 int ret;
 194                 int irq_was_disabled;
 195
 196                 args = next_arg(args, &param, &val);
 197                 irq_was_disabled = irqs_disabled();
 198                 ret = parse_one(param, val, params, num, unknown);
 199                 if (irq_was_disabled && !irqs_disabled()) {
 200                         printk(KERN_WARNING "parse_args(): option '%s' enabled "
 201                                         "irq's!\n", param);
 202                 }
 203                 switch (ret) {
 204                 case -ENOENT:
 205                         printk(KERN_ERR "%s: Unknown parameter `%s'\n",
 206                                name, param);
 207                         return ret;
 208                 case -ENOSPC:
 209                         printk(KERN_ERR
 210                                "%s: `%s' too large for parameter `%s'\n",
 211                                name, val ?: "", param);
 212                         return ret;
 213                 case 0:
 214                         break;
 215                 default:
 216                         printk(KERN_ERR
 217                                "%s: `%s' invalid for parameter `%s'\n",
 218                                name, val ?: "", param);
 219                         return ret;
 220                 }
 221         }
 222
 223         /* All parsed OK. */
 224         return 0;
 225 }
 226
 227 /* Lazy bastard, eh? */
 228 #define STANDARD_PARAM_DEF(name, type, format, tmptype, strtolfn)       \
 229         int param_set_##name(const char *val, const struct kernel_param *kp) \
 230         {                                                               \
 231                 tmptype l;                                              \
 232                 int ret;                                                \
 233                                                                         \
 234                 ret = strtolfn(val, 0, &l);                             \
 235                 if (ret < 0 || ((type)l != l))                          \
 236                         return ret < 0 ? ret : -EINVAL;                 \
 237                 *((type *)kp->arg) = l;                                 \
 238                 return 0;                                               \
 239         }                                                               \
 240         int param_get_##name(char *buffer, const struct kernel_param *kp) \
 241         {                                                               \
 242                 return sprintf(buffer, format, *((type *)kp->arg));     \
 243         }                                                               \
 244         struct kernel_param_ops param_ops_##name = {                    \
 245                 .set = param_set_##name,                                \
 246                 .get = param_get_##name,                                \
 247         };                                                              \
 248         EXPORT_SYMBOL(param_set_##name);                                \
 249         EXPORT_SYMBOL(param_get_##name);                                \
 250         EXPORT_SYMBOL(param_ops_##name)
 251
 252
 253 STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, strict_strtoul);
 254 STANDARD_PARAM_DEF(short, short, "%hi", long, strict_strtol);
 255 STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, strict_strtoul);
 256 STANDARD_PARAM_DEF(int, int, "%i", long, strict_strtol);
 257 STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, strict_strtoul);
 258 STANDARD_PARAM_DEF(long, long, "%li", long, strict_strtol);
 259 STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, strict_strtoul);
 260
 261 int param_set_charp(const char *val, const struct kernel_param *kp)
 262 {
 263         if (strlen(val) > 1024) {
 264                 printk(KERN_ERR "%s: string parameter too long\n",
 265                        kp->name);
 266                 return -ENOSPC;
 267         }
 268
 269         maybe_kfree_parameter(*(char **)kp->arg);
 270
 271         /* This is a hack.  We can't kmalloc in early boot, and we
 272          * don't need to; this mangled commandline is preserved. */
 273         if (slab_is_available()) {
 274                 *(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
 275                 if (!*(char **)kp->arg)
 276                         return -ENOMEM;
 277                 strcpy(*(char **)kp->arg, val);
 278         } else
 279                 *(const char **)kp->arg = val;
 280
 281         return 0;
 282 }
 283 EXPORT_SYMBOL(param_set_charp);
 284
 285 int param_get_charp(char *buffer, const struct kernel_param *kp)
 286 {
 287         return sprintf(buffer, "%s", *((char **)kp->arg));
 288 }
 289 EXPORT_SYMBOL(param_get_charp);
 290
 291 static void param_free_charp(void *arg)
 292 {
 293         maybe_kfree_parameter(*((char **)arg));
 294 }
 295
 296 struct kernel_param_ops param_ops_charp = {
 297         .set = param_set_charp,
 298         .get = param_get_charp,
 299         .free = param_free_charp,
 300 };
 301 EXPORT_SYMBOL(param_ops_charp);
 302
 303 /* Actually could be a bool or an int, for historical reasons. */
 304 int param_set_bool(const char *val, const struct kernel_param *kp)
 305 {
 306         bool v;
 307         int ret;
 308
 309         /* No equals means "set"... */
 310         if (!val) val = "1";
 311
 312         /* One of =[yYnN01] */
 313         ret = strtobool(val, &v);
 314         if (ret)
 315                 return ret;
 316
 317         if (kp->flags & KPARAM_ISBOOL)
 318                 *(bool *)kp->arg = v;
 319         else
 320                 *(int *)kp->arg = v;
 321         return 0;
 322 }
 323 EXPORT_SYMBOL(param_set_bool);
 324
 325 int param_get_bool(char *buffer, const struct kernel_param *kp)
 326 {
 327         bool val;
 328         if (kp->flags & KPARAM_ISBOOL)
 329                 val = *(bool *)kp->arg;
 330         else
 331                 val = *(int *)kp->arg;
 332
 333         /* Y and N chosen as being relatively non-coder friendly */
 334         return sprintf(buffer, "%c", val ? 'Y' : 'N');
 335 }
 336 EXPORT_SYMBOL(param_get_bool);
 337
 338 struct kernel_param_ops param_ops_bool = {
 339         .set = param_set_bool,
 340         .get = param_get_bool,
 341 };
 342 EXPORT_SYMBOL(param_ops_bool);
 343
 344 /* This one must be bool. */
 345 int param_set_invbool(const char *val, const struct kernel_param *kp)
 346 {
 347         int ret;
 348         bool boolval;
 349         struct kernel_param dummy;
 350
 351         dummy.arg = &boolval;
 352         dummy.flags = KPARAM_ISBOOL;
 353         ret = param_set_bool(val, &dummy);
 354         if (ret == 0)
 355                 *(bool *)kp->arg = !boolval;
 356         return ret;
 357 }
 358 EXPORT_SYMBOL(param_set_invbool);
 359
 360 int param_get_invbool(char *buffer, const struct kernel_param *kp)
 361 {
 362         return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
 363 }
 364 EXPORT_SYMBOL(param_get_invbool);
 365
 366 struct kernel_param_ops param_ops_invbool = {
 367         .set = param_set_invbool,
 368         .get = param_get_invbool,
 369 };
 370 EXPORT_SYMBOL(param_ops_invbool);
 371
 372 /* We break the rule and mangle the string. */
 373 static int param_array(const char *name,
 374                        const char *val,
 375                        unsigned int min, unsigned int max,
 376                        void *elem, int elemsize,
 377                        int (*set)(const char *, const struct kernel_param *kp),
 378                        u16 flags,
 379                        unsigned int *num)
 380 {
 381         int ret;
 382         struct kernel_param kp;
 383         char save;
 384
 385         /* Get the name right for errors. */
 386         kp.name = name;
 387         kp.arg = elem;
 388         kp.flags = flags;
 389
 390         *num = 0;
 391         /* We expect a comma-separated list of values. */
 392         do {
 393                 int len;
 394
 395                 if (*num == max) {
 396                         printk(KERN_ERR "%s: can only take %i arguments\n",
 397                                name, max);
 398                         return -EINVAL;
 399                 }
 400                 len = strcspn(val, ",");
 401
 402                 /* nul-terminate and parse */
 403                 save = val[len];
 404                 ((char *)val)[len] = '\0';
 405                 BUG_ON(!mutex_is_locked(&param_lock));
 406                 ret = set(val, &kp);
 407
 408                 if (ret != 0)
 409                         return ret;
 410                 kp.arg += elemsize;
 411                 val += len+1;
 412                 (*num)++;
 413         } while (save == ',');
 414
 415         if (*num < min) {
 416                 printk(KERN_ERR "%s: needs at least %i arguments\n",
 417                        name, min);
 418                 return -EINVAL;
 419         }
 420         return 0;
 421 }
 422
 423 static int param_array_set(const char *val, const struct kernel_param *kp)
 424 {
 425         const struct kparam_array *arr = kp->arr;
 426         unsigned int temp_num;
 427
 428         return param_array(kp->name, val, 1, arr->max, arr->elem,
 429                            arr->elemsize, arr->ops->set, kp->flags,
 430                            arr->num ?: &temp_num);
 431 }
 432
 433 static int param_array_get(char *buffer, const struct kernel_param *kp)
 434 {
 435         int i, off, ret;
 436         const struct kparam_array *arr = kp->arr;
 437         struct kernel_param p;
 438
 439         p = *kp;
 440         for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 441                 if (i)
 442                         buffer[off++] = ',';
 443                 p.arg = arr->elem + arr->elemsize * i;
 444                 BUG_ON(!mutex_is_locked(&param_lock));
 445                 ret = arr->ops->get(buffer + off, &p);
 446                 if (ret < 0)
 447                         return ret;
 448                 off += ret;
 449         }
 450         buffer[off] = '\0';
 451         return off;
 452 }
 453
 454 static void param_array_free(void *arg)
 455 {
 456         unsigned int i;
 457         const struct kparam_array *arr = arg;
 458
 459         if (arr->ops->free)
 460                 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
 461                         arr->ops->free(arr->elem + arr->elemsize * i);
 462 }
 463
 464 struct kernel_param_ops param_array_ops = {
 465         .set = param_array_set,
 466         .get = param_array_get,
 467         .free = param_array_free,
 468 };
 469 EXPORT_SYMBOL(param_array_ops);
 470
 471 int param_set_copystring(const char *val, const struct kernel_param *kp)
 472 {
 473         const struct kparam_string *kps = kp->str;
 474
 475         if (strlen(val)+1 > kps->maxlen) {
 476                 printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
 477                        kp->name, kps->maxlen-1);
 478                 return -ENOSPC;
 479         }
 480         strcpy(kps->string, val);
 481         return 0;
 482 }
 483 EXPORT_SYMBOL(param_set_copystring);
 484
 485 int param_get_string(char *buffer, const struct kernel_param *kp)
 486 {
 487         const struct kparam_string *kps = kp->str;
 488         return strlcpy(buffer, kps->string, kps->maxlen);
 489 }
 490 EXPORT_SYMBOL(param_get_string);
 491
 492 struct kernel_param_ops param_ops_string = {
 493         .set = param_set_copystring,
 494         .get = param_get_string,
 495 };
 496 EXPORT_SYMBOL(param_ops_string);
 497
 498 /* sysfs output in /sys/modules/XYZ/parameters/ */
 499 #define to_module_attr(n) container_of(n, struct module_attribute, attr)
 500 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj)
 501
 502 extern struct kernel_param __start___param[], __stop___param[];
 503
 504 struct param_attribute
 505 {
 506         struct module_attribute mattr;
 507         const struct kernel_param *param;
 508 };
 509
 510 struct module_param_attrs
 511 {
 512         unsigned int num;
 513         struct attribute_group grp;
 514         struct param_attribute attrs[0];
 515 };
 516
 517 #ifdef CONFIG_SYSFS
 518 #define to_param_attr(n) container_of(n, struct param_attribute, mattr)
 519
 520 static ssize_t param_attr_show(struct module_attribute *mattr,
 521                                struct module_kobject *mk, char *buf)
 522 {
 523         int count;
 524         struct param_attribute *attribute = to_param_attr(mattr);
 525
 526         if (!attribute->param->ops->get)
 527                 return -EPERM;
 528
 529         mutex_lock(&param_lock);
 530         count = attribute->param->ops->get(buf, attribute->param);
 531         mutex_unlock(&param_lock);
 532         if (count > 0) {
 533                 strcat(buf, "\n");
 534                 ++count;
 535         }
 536         return count;
 537 }
 538
 539 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 540 static ssize_t param_attr_store(struct module_attribute *mattr,
 541                                 struct module_kobject *km,
 542                                 const char *buf, size_t len)
 543 {
 544         int err;
 545         struct param_attribute *attribute = to_param_attr(mattr);
 546
 547         if (!attribute->param->ops->set)
 548                 return -EPERM;
 549
 550         mutex_lock(&param_lock);
 551         err = attribute->param->ops->set(buf, attribute->param);
 552         mutex_unlock(&param_lock);
 553         if (!err)
 554                 return len;
 555         return err;
 556 }
 557 #endif
 558
 559 #ifdef CONFIG_MODULES
 560 #define __modinit
 561 #else
 562 #define __modinit __init
 563 #endif
 564
 565 #ifdef CONFIG_SYSFS
 566 void __kernel_param_lock(void)
 567 {
 568         mutex_lock(&param_lock);
 569 }
 570 EXPORT_SYMBOL(__kernel_param_lock);
 571
 572 void __kernel_param_unlock(void)
 573 {
 574         mutex_unlock(&param_lock);
 575 }
 576 EXPORT_SYMBOL(__kernel_param_unlock);
 577
 578 /*
 579  * add_sysfs_param - add a parameter to sysfs
 580  * @mk: struct module_kobject
 581  * @kparam: the actual parameter definition to add to sysfs
 582  * @name: name of parameter
 583  *
 584  * Create a kobject if for a (per-module) parameter if mp NULL, and
 585  * create file in sysfs.  Returns an error on out of memory.  Always cleans up
 586  * if there's an error.
 587  */
 588 static __modinit int add_sysfs_param(struct module_kobject *mk,
 589                                      const struct kernel_param *kp,
 590                                      const char *name)
 591 {
 592         struct module_param_attrs *new;
 593         struct attribute **attrs;
 594         int err, num;
 595
 596         /* We don't bother calling this with invisible parameters. */
 597         BUG_ON(!kp->perm);
 598
 599         if (!mk->mp) {
 600                 num = 0;
 601                 attrs = NULL;
 602         } else {
 603                 num = mk->mp->num;
 604                 attrs = mk->mp->grp.attrs;
 605         }
 606
 607         /* Enlarge. */
 608         new = krealloc(mk->mp,
 609                        sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
 610                        GFP_KERNEL);
 611         if (!new) {
 612                 kfree(mk->mp);
 613                 err = -ENOMEM;
 614                 goto fail;
 615         }
 616         attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
 617         if (!attrs) {
 618                 err = -ENOMEM;
 619                 goto fail_free_new;
 620         }
 621
 622         /* Sysfs wants everything zeroed. */
 623         memset(new, 0, sizeof(*new));
 624         memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
 625         memset(&attrs[num], 0, sizeof(attrs[num]));
 626         new->grp.name = "parameters";
 627         new->grp.attrs = attrs;
 628
 629         /* Tack new one on the end. */
 630         sysfs_attr_init(&new->attrs[num].mattr.attr);
 631         new->attrs[num].param = kp;
 632         new->attrs[num].mattr.show = param_attr_show;
 633         new->attrs[num].mattr.store = param_attr_store;
 634         new->attrs[num].mattr.attr.name = (char *)name;
 635         new->attrs[num].mattr.attr.mode = kp->perm;
 636         new->num = num+1;
 637
 638         /* Fix up all the pointers, since krealloc can move us */
 639         for (num = 0; num < new->num; num++)
 640                 new->grp.attrs[num] = &new->attrs[num].mattr.attr;
 641         new->grp.attrs[num] = NULL;
 642
 643         mk->mp = new;
 644         return 0;
 645
 646 fail_free_new:
 647         kfree(new);
 648 fail:
 649         mk->mp = NULL;
 650         return err;
 651 }
 652
 653 #ifdef CONFIG_MODULES
 654 static void free_module_param_attrs(struct module_kobject *mk)
 655 {
 656         kfree(mk->mp->grp.attrs);
 657         kfree(mk->mp);
 658         mk->mp = NULL;
 659 }
 660
 661 /*
 662  * module_param_sysfs_setup - setup sysfs support for one module
 663  * @mod: module
 664  * @kparam: module parameters (array)
 665  * @num_params: number of module parameters
 666  *
 667  * Adds sysfs entries for module parameters under
 668  * /sys/module/[mod->name]/parameters/
 669  */
 670 int module_param_sysfs_setup(struct module *mod,
 671                              const struct kernel_param *kparam,
 672                              unsigned int num_params)
 673 {
 674         int i, err;
 675         bool params = false;
 676
 677         for (i = 0; i < num_params; i++) {
 678                 if (kparam[i].perm == 0)
 679                         continue;
 680                 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
 681                 if (err)
 682                         return err;
 683                 params = true;
 684         }
 685
 686         if (!params)
 687                 return 0;
 688
 689         /* Create the param group. */
 690         err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 691         if (err)
 692                 free_module_param_attrs(&mod->mkobj);
 693         return err;
 694 }
 695
 696 /*
 697  * module_param_sysfs_remove - remove sysfs support for one module
 698  * @mod: module
 699  *
 700  * Remove sysfs entries for module parameters and the corresponding
 701  * kobject.
 702  */
 703 void module_param_sysfs_remove(struct module *mod)
 704 {
 705         if (mod->mkobj.mp) {
 706                 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
 707                 /* We are positive that no one is using any param
 708                  * attrs at this point.  Deallocate immediately. */
 709                 free_module_param_attrs(&mod->mkobj);
 710         }
 711 }
 712 #endif
 713
 714 void destroy_params(const struct kernel_param *params, unsigned num)
 715 {
 716         unsigned int i;
 717
 718         for (i = 0; i < num; i++)
 719                 if (params[i].ops->free)
 720                         params[i].ops->free(params[i].arg);
 721 }
 722
 723 static struct module_kobject * __init locate_module_kobject(const char *name)
 724 {
 725         struct module_kobject *mk;
 726         struct kobject *kobj;
 727         int err;
 728
 729         kobj = kset_find_obj(module_kset, name);
 730         if (kobj) {
 731                 mk = to_module_kobject(kobj);
 732         } else {
 733                 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
 734                 BUG_ON(!mk);
 735
 736                 mk->mod = THIS_MODULE;
 737                 mk->kobj.kset = module_kset;
 738                 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
 739                                            "%s", name);
 740 #ifdef CONFIG_MODULES
 741                 if (!err)
 742                         err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
 743 #endif
 744                 if (err) {
 745                         kobject_put(&mk->kobj);
 746                         printk(KERN_ERR
 747                                 "Module '%s' failed add to sysfs, error number %d\n",
 748                                 name, err);
 749                         printk(KERN_ERR
 750                                 "The system will be unstable now.\n");
 751                         return NULL;
 752                 }
 753
 754                 /* So that we hold reference in both cases. */
 755                 kobject_get(&mk->kobj);
 756         }
 757
 758         return mk;
 759 }
 760
 761 static void __init kernel_add_sysfs_param(const char *name,
 762                                           struct kernel_param *kparam,
 763                                           unsigned int name_skip)
 764 {
 765         struct module_kobject *mk;
 766         int err;
 767
 768         mk = locate_module_kobject(name);
 769         if (!mk)
 770                 return;
 771
 772         /* We need to remove old parameters before adding more. */
 773         if (mk->mp)
 774                 sysfs_remove_group(&mk->kobj, &mk->mp->grp);
 775
 776         /* These should not fail at boot. */
 777         err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
 778         BUG_ON(err);
 779         err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
 780         BUG_ON(err);
 781         kobject_uevent(&mk->kobj, KOBJ_ADD);
 782         kobject_put(&mk->kobj);
 783 }
 784
 785 /*
 786  * param_sysfs_builtin - add contents in /sys/parameters for built-in modules
 787  *
 788  * Add module_parameters to sysfs for "modules" built into the kernel.
 789  *
 790  * The "module" name (KBUILD_MODNAME) is stored before a dot, the
 791  * "parameter" name is stored behind a dot in kernel_param->name. So,
 792  * extract the "module" name for all built-in kernel_param-eters,
 793  * and for all who have the same, call kernel_add_sysfs_param.
 794  */
 795 static void __init param_sysfs_builtin(void)
 796 {
 797         struct kernel_param *kp;
 798         unsigned int name_len;
 799         char modname[MODULE_NAME_LEN];
 800
 801         for (kp = __start___param; kp < __stop___param; kp++) {
 802                 char *dot;
 803
 804                 if (kp->perm == 0)
 805                         continue;
 806
 807                 dot = strchr(kp->name, '.');
 808                 if (!dot) {
 809                         /* This happens for core_param() */
 810                         strcpy(modname, "kernel");
 811                         name_len = 0;
 812                 } else {
 813                         name_len = dot - kp->name + 1;
 814                         strlcpy(modname, kp->name, name_len);
 815                 }
 816                 kernel_add_sysfs_param(modname, kp, name_len);
 817         }
 818 }
 819
 820 ssize_t __modver_version_show(struct module_attribute *mattr,
 821                               struct module_kobject *mk, char *buf)
 822 {
 823         struct module_version_attribute *vattr =
 824                 container_of(mattr, struct module_version_attribute, mattr);
 825
 826         return sprintf(buf, "%s\n", vattr->version);
 827 }
 828
 829 extern const struct module_version_attribute *__start___modver[];
 830 extern const struct module_version_attribute *__stop___modver[];
 831
 832 static void __init version_sysfs_builtin(void)
 833 {
 834         const struct module_version_attribute **p;
 835         struct module_kobject *mk;
 836         int err;
 837
 838         for (p = __start___modver; p < __stop___modver; p++) {
 839                 const struct module_version_attribute *vattr = *p;
 840
 841                 mk = locate_module_kobject(vattr->module_name);
 842                 if (mk) {
 843                         err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
 844                         kobject_uevent(&mk->kobj, KOBJ_ADD);
 845                         kobject_put(&mk->kobj);
 846                 }
 847         }
 848 }
 849
 850 /* module-related sysfs stuff */
 851
 852 static ssize_t module_attr_show(struct kobject *kobj,
 853                                 struct attribute *attr,
 854                                 char *buf)
 855 {
 856         struct module_attribute *attribute;
 857         struct module_kobject *mk;
 858         int ret;
 859
 860         attribute = to_module_attr(attr);
 861         mk = to_module_kobject(kobj);
 862
 863         if (!attribute->show)
 864                 return -EIO;
 865
 866         ret = attribute->show(attribute, mk, buf);
 867
 868         return ret;
 869 }
 870
 871 static ssize_t module_attr_store(struct kobject *kobj,
 872                                 struct attribute *attr,
 873                                 const char *buf, size_t len)
 874 {
 875         struct module_attribute *attribute;
 876         struct module_kobject *mk;
 877         int ret;
 878
 879         attribute = to_module_attr(attr);
 880         mk = to_module_kobject(kobj);
 881
 882         if (!attribute->store)
 883                 return -EIO;
 884
 885         ret = attribute->store(attribute, mk, buf, len);
 886
 887         return ret;
 888 }
 889
 890 static const struct sysfs_ops module_sysfs_ops = {
 891         .show = module_attr_show,
 892         .store = module_attr_store,
 893 };
 894
 895 static int uevent_filter(struct kset *kset, struct kobject *kobj)
 896 {
 897         struct kobj_type *ktype = get_ktype(kobj);
 898
 899         if (ktype == &module_ktype)
 900                 return 1;
 901         return 0;
 902 }
 903
 904 static const struct kset_uevent_ops module_uevent_ops = {
 905         .filter = uevent_filter,
 906 };
 907
 908 struct kset *module_kset;
 909 int module_sysfs_initialized;
 910
 911 struct kobj_type module_ktype = {
 912         .sysfs_ops =    &module_sysfs_ops,
 913 };
 914
 915 /*
 916  * param_sysfs_init - wrapper for built-in params support
 917  */
 918 static int __init param_sysfs_init(void)
 919 {
 920         module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
 921         if (!module_kset) {
 922                 printk(KERN_WARNING "%s (%d): error creating kset\n",
 923                         __FILE__, __LINE__);
 924                 return -ENOMEM;
 925         }
 926         module_sysfs_initialized = 1;
 927
 928         version_sysfs_builtin();
 929         param_sysfs_builtin();
 930
 931         return 0;
 932 }
 933 subsys_initcall(param_sysfs_init);
 934
 935 #endif /* CONFIG_SYSFS */