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; 516 517 if (strnlen(val, kps->maxlen) == kps->maxlen) { 518 pr_err("%s: string doesn't fit in %u chars.\n", 519 kp->name, kps->maxlen-1); 520 return -ENOSPC; 521 } 522 strcpy(kps->string, val); 523 return 0; 524 } 525 EXPORT_SYMBOL(param_set_copystring); 526 527 int param_get_string(char *buffer, const struct kernel_param *kp) 528 { 529 const struct kparam_string *kps = kp->str; 530 return scnprintf(buffer, PAGE_SIZE, "%s\n", kps->string); 531 } 532 EXPORT_SYMBOL(param_get_string); 533 534 const struct kernel_param_ops param_ops_string = { 535 .set = param_set_copystring, 536 .get = param_get_string, 537 }; 538 EXPORT_SYMBOL(param_ops_string); 539 540 /* sysfs output in /sys/modules/XYZ/parameters/ */ 541 #define to_module_attr(n) container_of(n, struct module_attribute, attr) 542 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj) 543 544 struct param_attribute 545 { 546 struct module_attribute mattr; 547 const struct kernel_param *param; 548 }; 549 550 struct module_param_attrs 551 { 552 unsigned int num; 553 struct attribute_group grp; 554 struct param_attribute attrs[]; 555 }; 556 557 #ifdef CONFIG_SYSFS 558 #define to_param_attr(n) container_of(n, struct param_attribute, mattr) 559 560 static ssize_t param_attr_show(struct module_attribute *mattr, 561 struct module_kobject *mk, char *buf) 562 { 563 int count; 564 struct param_attribute *attribute = to_param_attr(mattr); 565 566 if (!attribute->param->ops->get) 567 return -EPERM; 568 569 kernel_param_lock(mk->mod); 570 count = attribute->param->ops->get(buf, attribute->param); 571 kernel_param_unlock(mk->mod); 572 return count; 573 } 574 575 /* sysfs always hands a nul-terminated string in buf. We rely on that. */ 576 static ssize_t param_attr_store(struct module_attribute *mattr, 577 struct module_kobject *mk, 578 const char *buf, size_t len) 579 { 580 int err; 581 struct param_attribute *attribute = to_param_attr(mattr); 582 583 if (!attribute->param->ops->set) 584 return -EPERM; 585 586 kernel_param_lock(mk->mod); 587 if (param_check_unsafe(attribute->param)) 588 err = attribute->param->ops->set(buf, attribute->param); 589 else 590 err = -EPERM; 591 kernel_param_unlock(mk->mod); 592 if (!err) 593 return len; 594 return err; 595 } 596 #endif 597 598 #ifdef CONFIG_MODULES 599 #define __modinit 600 #else 601 #define __modinit __init 602 #endif 603 604 #ifdef CONFIG_SYSFS 605 void kernel_param_lock(struct module *mod) 606 { 607 mutex_lock(KPARAM_MUTEX(mod)); 608 } 609 610 void kernel_param_unlock(struct module *mod) 611 { 612 mutex_unlock(KPARAM_MUTEX(mod)); 613 } 614 615 EXPORT_SYMBOL(kernel_param_lock); 616 EXPORT_SYMBOL(kernel_param_unlock); 617 618 /* 619 * add_sysfs_param - add a parameter to sysfs 620 * @mk: struct module_kobject 621 * @kp: the actual parameter definition to add to sysfs 622 * @name: name of parameter 623 * 624 * Create a kobject if for a (per-module) parameter if mp NULL, and 625 * create file in sysfs. Returns an error on out of memory. Always cleans up 626 * if there's an error. 627 */ 628 static __modinit int add_sysfs_param(struct module_kobject *mk, 629 const struct kernel_param *kp, 630 const char *name) 631 { 632 struct module_param_attrs *new_mp; 633 struct attribute **new_attrs; 634 unsigned int i; 635 636 /* We don't bother calling this with invisible parameters. */ 637 BUG_ON(!kp->perm); 638 639 if (!mk->mp) { 640 /* First allocation. */ 641 mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL); 642 if (!mk->mp) 643 return -ENOMEM; 644 mk->mp->grp.name = "parameters"; 645 /* NULL-terminated attribute array. */ 646 mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]), 647 GFP_KERNEL); 648 /* Caller will cleanup via free_module_param_attrs */ 649 if (!mk->mp->grp.attrs) 650 return -ENOMEM; 651 } 652 653 /* Enlarge allocations. */ 654 new_mp = krealloc(mk->mp, 655 sizeof(*mk->mp) + 656 sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1), 657 GFP_KERNEL); 658 if (!new_mp) 659 return -ENOMEM; 660 mk->mp = new_mp; 661 662 /* Extra pointer for NULL terminator */ 663 new_attrs = krealloc(mk->mp->grp.attrs, 664 sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2), 665 GFP_KERNEL); 666 if (!new_attrs) 667 return -ENOMEM; 668 mk->mp->grp.attrs = new_attrs; 669 670 /* Tack new one on the end. */ 671 memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0])); 672 sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr); 673 mk->mp->attrs[mk->mp->num].param = kp; 674 mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show; 675 /* Do not allow runtime DAC changes to make param writable. */ 676 if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0) 677 mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store; 678 else 679 mk->mp->attrs[mk->mp->num].mattr.store = NULL; 680 mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name; 681 mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm; 682 mk->mp->num++; 683 684 /* Fix up all the pointers, since krealloc can move us */ 685 for (i = 0; i < mk->mp->num; i++) 686 mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr; 687 mk->mp->grp.attrs[mk->mp->num] = NULL; 688 return 0; 689 } 690 691 #ifdef CONFIG_MODULES 692 static void free_module_param_attrs(struct module_kobject *mk) 693 { 694 if (mk->mp) 695 kfree(mk->mp->grp.attrs); 696 kfree(mk->mp); 697 mk->mp = NULL; 698 } 699 700 /* 701 * module_param_sysfs_setup - setup sysfs support for one module 702 * @mod: module 703 * @kparam: module parameters (array) 704 * @num_params: number of module parameters 705 * 706 * Adds sysfs entries for module parameters under 707 * /sys/module/[mod->name]/parameters/ 708 */ 709 int module_param_sysfs_setup(struct module *mod, 710 const struct kernel_param *kparam, 711 unsigned int num_params) 712 { 713 int i, err; 714 bool params = false; 715 716 for (i = 0; i < num_params; i++) { 717 if (kparam[i].perm == 0) 718 continue; 719 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name); 720 if (err) { 721 free_module_param_attrs(&mod->mkobj); 722 return err; 723 } 724 params = true; 725 } 726 727 if (!params) 728 return 0; 729 730 /* Create the param group. */ 731 err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp); 732 if (err) 733 free_module_param_attrs(&mod->mkobj); 734 return err; 735 } 736 737 /* 738 * module_param_sysfs_remove - remove sysfs support for one module 739 * @mod: module 740 * 741 * Remove sysfs entries for module parameters and the corresponding 742 * kobject. 743 */ 744 void module_param_sysfs_remove(struct module *mod) 745 { 746 if (mod->mkobj.mp) { 747 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp); 748 /* 749 * We are positive that no one is using any param 750 * attrs at this point. Deallocate immediately. 751 */ 752 free_module_param_attrs(&mod->mkobj); 753 } 754 } 755 #endif 756 757 void destroy_params(const struct kernel_param *params, unsigned num) 758 { 759 unsigned int i; 760 761 for (i = 0; i < num; i++) 762 if (params[i].ops->free) 763 params[i].ops->free(params[i].arg); 764 } 765 766 static struct module_kobject * __init locate_module_kobject(const char *name) 767 { 768 struct module_kobject *mk; 769 struct kobject *kobj; 770 int err; 771 772 kobj = kset_find_obj(module_kset, name); 773 if (kobj) { 774 mk = to_module_kobject(kobj); 775 } else { 776 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL); 777 BUG_ON(!mk); 778 779 mk->mod = THIS_MODULE; 780 mk->kobj.kset = module_kset; 781 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL, 782 "%s", name); 783 #ifdef CONFIG_MODULES 784 if (!err) 785 err = sysfs_create_file(&mk->kobj, &module_uevent.attr); 786 #endif 787 if (err) { 788 kobject_put(&mk->kobj); 789 pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n", 790 name, err); 791 return NULL; 792 } 793 794 /* So that we hold reference in both cases. */ 795 kobject_get(&mk->kobj); 796 } 797 798 return mk; 799 } 800 801 static void __init kernel_add_sysfs_param(const char *name, 802 const struct kernel_param *kparam, 803 unsigned int name_skip) 804 { 805 struct module_kobject *mk; 806 int err; 807 808 mk = locate_module_kobject(name); 809 if (!mk) 810 return; 811 812 /* We need to remove old parameters before adding more. */ 813 if (mk->mp) 814 sysfs_remove_group(&mk->kobj, &mk->mp->grp); 815 816 /* These should not fail at boot. */ 817 err = add_sysfs_param(mk, kparam, kparam->name + name_skip); 818 BUG_ON(err); 819 err = sysfs_create_group(&mk->kobj, &mk->mp->grp); 820 BUG_ON(err); 821 kobject_uevent(&mk->kobj, KOBJ_ADD); 822 kobject_put(&mk->kobj); 823 } 824 825 /* 826 * param_sysfs_builtin - add sysfs parameters for built-in modules 827 * 828 * Add module_parameters to sysfs for "modules" built into the kernel. 829 * 830 * The "module" name (KBUILD_MODNAME) is stored before a dot, the 831 * "parameter" name is stored behind a dot in kernel_param->name. So, 832 * extract the "module" name for all built-in kernel_param-eters, 833 * and for all who have the same, call kernel_add_sysfs_param. 834 */ 835 static void __init param_sysfs_builtin(void) 836 { 837 const struct kernel_param *kp; 838 unsigned int name_len; 839 char modname[MODULE_NAME_LEN]; 840 841 for (kp = __start___param; kp < __stop___param; kp++) { 842 char *dot; 843 844 if (kp->perm == 0) 845 continue; 846 847 dot = strchr(kp->name, '.'); 848 if (!dot) { 849 /* This happens for core_param() */ 850 strcpy(modname, "kernel"); 851 name_len = 0; 852 } else { 853 name_len = dot - kp->name + 1; 854 strscpy(modname, kp->name, name_len); 855 } 856 kernel_add_sysfs_param(modname, kp, name_len); 857 } 858 } 859 860 ssize_t __modver_version_show(struct module_attribute *mattr, 861 struct module_kobject *mk, char *buf) 862 { 863 struct module_version_attribute *vattr = 864 container_of(mattr, struct module_version_attribute, mattr); 865 866 return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version); 867 } 868 869 extern const struct module_version_attribute __start___modver[]; 870 extern const struct module_version_attribute __stop___modver[]; 871 872 static void __init version_sysfs_builtin(void) 873 { 874 const struct module_version_attribute *vattr; 875 struct module_kobject *mk; 876 int err; 877 878 for (vattr = __start___modver; vattr < __stop___modver; vattr++) { 879 mk = locate_module_kobject(vattr->module_name); 880 if (mk) { 881 err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr); 882 WARN_ON_ONCE(err); 883 kobject_uevent(&mk->kobj, KOBJ_ADD); 884 kobject_put(&mk->kobj); 885 } 886 } 887 } 888 889 /* module-related sysfs stuff */ 890 891 static ssize_t module_attr_show(struct kobject *kobj, 892 struct attribute *attr, 893 char *buf) 894 { 895 struct module_attribute *attribute; 896 struct module_kobject *mk; 897 int ret; 898 899 attribute = to_module_attr(attr); 900 mk = to_module_kobject(kobj); 901 902 if (!attribute->show) 903 return -EIO; 904 905 ret = attribute->show(attribute, mk, buf); 906 907 return ret; 908 } 909 910 static ssize_t module_attr_store(struct kobject *kobj, 911 struct attribute *attr, 912 const char *buf, size_t len) 913 { 914 struct module_attribute *attribute; 915 struct module_kobject *mk; 916 int ret; 917 918 attribute = to_module_attr(attr); 919 mk = to_module_kobject(kobj); 920 921 if (!attribute->store) 922 return -EIO; 923 924 ret = attribute->store(attribute, mk, buf, len); 925 926 return ret; 927 } 928 929 static const struct sysfs_ops module_sysfs_ops = { 930 .show = module_attr_show, 931 .store = module_attr_store, 932 }; 933 934 static int uevent_filter(const struct kobject *kobj) 935 { 936 const struct kobj_type *ktype = get_ktype(kobj); 937 938 if (ktype == &module_ktype) 939 return 1; 940 return 0; 941 } 942 943 static const struct kset_uevent_ops module_uevent_ops = { 944 .filter = uevent_filter, 945 }; 946 947 struct kset *module_kset; 948 949 static void module_kobj_release(struct kobject *kobj) 950 { 951 struct module_kobject *mk = to_module_kobject(kobj); 952 complete(mk->kobj_completion); 953 } 954 955 const struct kobj_type module_ktype = { 956 .release = module_kobj_release, 957 .sysfs_ops = &module_sysfs_ops, 958 }; 959 960 /* 961 * param_sysfs_init - create "module" kset 962 * 963 * This must be done before the initramfs is unpacked and 964 * request_module() thus becomes possible, because otherwise the 965 * module load would fail in mod_sysfs_init. 966 */ 967 static int __init param_sysfs_init(void) 968 { 969 module_kset = kset_create_and_add("module", &module_uevent_ops, NULL); 970 if (!module_kset) { 971 printk(KERN_WARNING "%s (%d): error creating kset\n", 972 __FILE__, __LINE__); 973 return -ENOMEM; 974 } 975 976 return 0; 977 } 978 subsys_initcall(param_sysfs_init); 979 980 /* 981 * param_sysfs_builtin_init - add sysfs version and parameter 982 * attributes for built-in modules 983 */ 984 static int __init param_sysfs_builtin_init(void) 985 { 986 if (!module_kset) 987 return -ENOMEM; 988 989 version_sysfs_builtin(); 990 param_sysfs_builtin(); 991 992 return 0; 993 } 994 late_initcall(param_sysfs_builtin_init); 995 996 #endif /* CONFIG_SYSFS */ 997