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