kernel/params.c

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