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