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); 244 245 int param_set_charp(const char *val, const struct kernel_param *kp) 246 { 247 if (strlen(val) > 1024) { 248 pr_err("%s: string parameter too long\n", kp->name); 249 return -ENOSPC; 250 } 251 252 maybe_kfree_parameter(*(char **)kp->arg); 253 254 /* This is a hack. We can't kmalloc in early boot, and we 255 * don't need to; this mangled commandline is preserved. */ 256 if (slab_is_available()) { 257 *(char **)kp->arg = kmalloc_parameter(strlen(val)+1); 258 if (!*(char **)kp->arg) 259 return -ENOMEM; 260 strcpy(*(char **)kp->arg, val); 261 } else 262 *(const char **)kp->arg = val; 263 264 return 0; 265 } 266 EXPORT_SYMBOL(param_set_charp); 267 268 int param_get_charp(char *buffer, const struct kernel_param *kp) 269 { 270 return scnprintf(buffer, PAGE_SIZE, "%s\n", *((char **)kp->arg)); 271 } 272 EXPORT_SYMBOL(param_get_charp); 273 274 void param_free_charp(void *arg) 275 { 276 maybe_kfree_parameter(*((char **)arg)); 277 } 278 EXPORT_SYMBOL(param_free_charp); 279 280 const struct kernel_param_ops param_ops_charp = { 281 .set = param_set_charp, 282 .get = param_get_charp, 283 .free = param_free_charp, 284 }; 285 EXPORT_SYMBOL(param_ops_charp); 286 287 /* Actually could be a bool or an int, for historical reasons. */ 288 int param_set_bool(const char *val, const struct kernel_param *kp) 289 { 290 /* No equals means "set"... */ 291 if (!val) val = "1"; 292 293 /* One of =[yYnN01] */ 294 return strtobool(val, kp->arg); 295 } 296 EXPORT_SYMBOL(param_set_bool); 297 298 int param_get_bool(char *buffer, const struct kernel_param *kp) 299 { 300 /* Y and N chosen as being relatively non-coder friendly */ 301 return sprintf(buffer, "%c\n", *(bool *)kp->arg ? 'Y' : 'N'); 302 } 303 EXPORT_SYMBOL(param_get_bool); 304 305 const struct kernel_param_ops param_ops_bool = { 306 .flags = KERNEL_PARAM_OPS_FL_NOARG, 307 .set = param_set_bool, 308 .get = param_get_bool, 309 }; 310 EXPORT_SYMBOL(param_ops_bool); 311 312 int param_set_bool_enable_only(const char *val, const struct kernel_param *kp) 313 { 314 int err = 0; 315 bool new_value; 316 bool orig_value = *(bool *)kp->arg; 317 struct kernel_param dummy_kp = *kp; 318 319 dummy_kp.arg = &new_value; 320 321 err = param_set_bool(val, &dummy_kp); 322 if (err) 323 return err; 324 325 /* Don't let them unset it once it's set! */ 326 if (!new_value && orig_value) 327 return -EROFS; 328 329 if (new_value) 330 err = param_set_bool(val, kp); 331 332 return err; 333 } 334 EXPORT_SYMBOL_GPL(param_set_bool_enable_only); 335 336 const struct kernel_param_ops param_ops_bool_enable_only = { 337 .flags = KERNEL_PARAM_OPS_FL_NOARG, 338 .set = param_set_bool_enable_only, 339 .get = param_get_bool, 340 }; 341 EXPORT_SYMBOL_GPL(param_ops_bool_enable_only); 342 343 /* This one must be bool. */ 344 int param_set_invbool(const char *val, const struct kernel_param *kp) 345 { 346 int ret; 347 bool boolval; 348 struct kernel_param dummy; 349 350 dummy.arg = &boolval; 351 ret = param_set_bool(val, &dummy); 352 if (ret == 0) 353 *(bool *)kp->arg = !boolval; 354 return ret; 355 } 356 EXPORT_SYMBOL(param_set_invbool); 357 358 int param_get_invbool(char *buffer, const struct kernel_param *kp) 359 { 360 return sprintf(buffer, "%c\n", (*(bool *)kp->arg) ? 'N' : 'Y'); 361 } 362 EXPORT_SYMBOL(param_get_invbool); 363 364 const struct kernel_param_ops param_ops_invbool = { 365 .set = param_set_invbool, 366 .get = param_get_invbool, 367 }; 368 EXPORT_SYMBOL(param_ops_invbool); 369 370 int param_set_bint(const char *val, const struct kernel_param *kp) 371 { 372 /* Match bool exactly, by re-using it. */ 373 struct kernel_param boolkp = *kp; 374 bool v; 375 int ret; 376 377 boolkp.arg = &v; 378 379 ret = param_set_bool(val, &boolkp); 380 if (ret == 0) 381 *(int *)kp->arg = v; 382 return ret; 383 } 384 EXPORT_SYMBOL(param_set_bint); 385 386 const struct kernel_param_ops param_ops_bint = { 387 .flags = KERNEL_PARAM_OPS_FL_NOARG, 388 .set = param_set_bint, 389 .get = param_get_int, 390 }; 391 EXPORT_SYMBOL(param_ops_bint); 392 393 /* We break the rule and mangle the string. */ 394 static int param_array(struct module *mod, 395 const char *name, 396 const char *val, 397 unsigned int min, unsigned int max, 398 void *elem, int elemsize, 399 int (*set)(const char *, const struct kernel_param *kp), 400 s16 level, 401 unsigned int *num) 402 { 403 int ret; 404 struct kernel_param kp; 405 char save; 406 407 /* Get the name right for errors. */ 408 kp.name = name; 409 kp.arg = elem; 410 kp.level = level; 411 412 *num = 0; 413 /* We expect a comma-separated list of values. */ 414 do { 415 int len; 416 417 if (*num == max) { 418 pr_err("%s: can only take %i arguments\n", name, max); 419 return -EINVAL; 420 } 421 len = strcspn(val, ","); 422 423 /* nul-terminate and parse */ 424 save = val[len]; 425 ((char *)val)[len] = '\0'; 426 check_kparam_locked(mod); 427 ret = set(val, &kp); 428 429 if (ret != 0) 430 return ret; 431 kp.arg += elemsize; 432 val += len+1; 433 (*num)++; 434 } while (save == ','); 435 436 if (*num < min) { 437 pr_err("%s: needs at least %i arguments\n", name, min); 438 return -EINVAL; 439 } 440 return 0; 441 } 442 443 static int param_array_set(const char *val, const struct kernel_param *kp) 444 { 445 const struct kparam_array *arr = kp->arr; 446 unsigned int temp_num; 447 448 return param_array(kp->mod, kp->name, val, 1, arr->max, arr->elem, 449 arr->elemsize, arr->ops->set, kp->level, 450 arr->num ?: &temp_num); 451 } 452 453 static int param_array_get(char *buffer, const struct kernel_param *kp) 454 { 455 int i, off, ret; 456 const struct kparam_array *arr = kp->arr; 457 struct kernel_param p = *kp; 458 459 for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) { 460 /* Replace \n with comma */ 461 if (i) 462 buffer[off - 1] = ','; 463 p.arg = arr->elem + arr->elemsize * i; 464 check_kparam_locked(p.mod); 465 ret = arr->ops->get(buffer + off, &p); 466 if (ret < 0) 467 return ret; 468 off += ret; 469 } 470 buffer[off] = '\0'; 471 return off; 472 } 473 474 static void param_array_free(void *arg) 475 { 476 unsigned int i; 477 const struct kparam_array *arr = arg; 478 479 if (arr->ops->free) 480 for (i = 0; i < (arr->num ? *arr->num : arr->max); i++) 481 arr->ops->free(arr->elem + arr->elemsize * i); 482 } 483 484 const struct kernel_param_ops param_array_ops = { 485 .set = param_array_set, 486 .get = param_array_get, 487 .free = param_array_free, 488 }; 489 EXPORT_SYMBOL(param_array_ops); 490 491 int param_set_copystring(const char *val, const struct kernel_param *kp) 492 { 493 const struct kparam_string *kps = kp->str; 494 495 if (strlen(val)+1 > kps->maxlen) { 496 pr_err("%s: string doesn't fit in %u chars.\n", 497 kp->name, kps->maxlen-1); 498 return -ENOSPC; 499 } 500 strcpy(kps->string, val); 501 return 0; 502 } 503 EXPORT_SYMBOL(param_set_copystring); 504 505 int param_get_string(char *buffer, const struct kernel_param *kp) 506 { 507 const struct kparam_string *kps = kp->str; 508 return scnprintf(buffer, PAGE_SIZE, "%s\n", kps->string); 509 } 510 EXPORT_SYMBOL(param_get_string); 511 512 const struct kernel_param_ops param_ops_string = { 513 .set = param_set_copystring, 514 .get = param_get_string, 515 }; 516 EXPORT_SYMBOL(param_ops_string); 517 518 /* sysfs output in /sys/modules/XYZ/parameters/ */ 519 #define to_module_attr(n) container_of(n, struct module_attribute, attr) 520 #define to_module_kobject(n) container_of(n, struct module_kobject, kobj) 521 522 struct param_attribute 523 { 524 struct module_attribute mattr; 525 const struct kernel_param *param; 526 }; 527 528 struct module_param_attrs 529 { 530 unsigned int num; 531 struct attribute_group grp; 532 struct param_attribute attrs[0]; 533 }; 534 535 #ifdef CONFIG_SYSFS 536 #define to_param_attr(n) container_of(n, struct param_attribute, mattr) 537 538 static ssize_t param_attr_show(struct module_attribute *mattr, 539 struct module_kobject *mk, char *buf) 540 { 541 int count; 542 struct param_attribute *attribute = to_param_attr(mattr); 543 544 if (!attribute->param->ops->get) 545 return -EPERM; 546 547 kernel_param_lock(mk->mod); 548 count = attribute->param->ops->get(buf, attribute->param); 549 kernel_param_unlock(mk->mod); 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 *mk, 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 kernel_param_lock(mk->mod); 565 if (param_check_unsafe(attribute->param)) 566 err = attribute->param->ops->set(buf, attribute->param); 567 else 568 err = -EPERM; 569 kernel_param_unlock(mk->mod); 570 if (!err) 571 return len; 572 return err; 573 } 574 #endif 575 576 #ifdef CONFIG_MODULES 577 #define __modinit 578 #else 579 #define __modinit __init 580 #endif 581 582 #ifdef CONFIG_SYSFS 583 void kernel_param_lock(struct module *mod) 584 { 585 mutex_lock(KPARAM_MUTEX(mod)); 586 } 587 588 void kernel_param_unlock(struct module *mod) 589 { 590 mutex_unlock(KPARAM_MUTEX(mod)); 591 } 592 593 EXPORT_SYMBOL(kernel_param_lock); 594 EXPORT_SYMBOL(kernel_param_unlock); 595 596 /* 597 * add_sysfs_param - add a parameter to sysfs 598 * @mk: struct module_kobject 599 * @kp: the actual parameter definition to add to sysfs 600 * @name: name of parameter 601 * 602 * Create a kobject if for a (per-module) parameter if mp NULL, and 603 * create file in sysfs. Returns an error on out of memory. Always cleans up 604 * if there's an error. 605 */ 606 static __modinit int add_sysfs_param(struct module_kobject *mk, 607 const struct kernel_param *kp, 608 const char *name) 609 { 610 struct module_param_attrs *new_mp; 611 struct attribute **new_attrs; 612 unsigned int i; 613 614 /* We don't bother calling this with invisible parameters. */ 615 BUG_ON(!kp->perm); 616 617 if (!mk->mp) { 618 /* First allocation. */ 619 mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL); 620 if (!mk->mp) 621 return -ENOMEM; 622 mk->mp->grp.name = "parameters"; 623 /* NULL-terminated attribute array. */ 624 mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]), 625 GFP_KERNEL); 626 /* Caller will cleanup via free_module_param_attrs */ 627 if (!mk->mp->grp.attrs) 628 return -ENOMEM; 629 } 630 631 /* Enlarge allocations. */ 632 new_mp = krealloc(mk->mp, 633 sizeof(*mk->mp) + 634 sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1), 635 GFP_KERNEL); 636 if (!new_mp) 637 return -ENOMEM; 638 mk->mp = new_mp; 639 640 /* Extra pointer for NULL terminator */ 641 new_attrs = krealloc(mk->mp->grp.attrs, 642 sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2), 643 GFP_KERNEL); 644 if (!new_attrs) 645 return -ENOMEM; 646 mk->mp->grp.attrs = new_attrs; 647 648 /* Tack new one on the end. */ 649 memset(&mk->mp->attrs[mk->mp->num], 0, sizeof(mk->mp->attrs[0])); 650 sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr); 651 mk->mp->attrs[mk->mp->num].param = kp; 652 mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show; 653 /* Do not allow runtime DAC changes to make param writable. */ 654 if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0) 655 mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store; 656 else 657 mk->mp->attrs[mk->mp->num].mattr.store = NULL; 658 mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name; 659 mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm; 660 mk->mp->num++; 661 662 /* Fix up all the pointers, since krealloc can move us */ 663 for (i = 0; i < mk->mp->num; i++) 664 mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr; 665 mk->mp->grp.attrs[mk->mp->num] = NULL; 666 return 0; 667 } 668 669 #ifdef CONFIG_MODULES 670 static void free_module_param_attrs(struct module_kobject *mk) 671 { 672 if (mk->mp) 673 kfree(mk->mp->grp.attrs); 674 kfree(mk->mp); 675 mk->mp = NULL; 676 } 677 678 /* 679 * module_param_sysfs_setup - setup sysfs support for one module 680 * @mod: module 681 * @kparam: module parameters (array) 682 * @num_params: number of module parameters 683 * 684 * Adds sysfs entries for module parameters under 685 * /sys/module/[mod->name]/parameters/ 686 */ 687 int module_param_sysfs_setup(struct module *mod, 688 const struct kernel_param *kparam, 689 unsigned int num_params) 690 { 691 int i, err; 692 bool params = false; 693 694 for (i = 0; i < num_params; i++) { 695 if (kparam[i].perm == 0) 696 continue; 697 err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name); 698 if (err) { 699 free_module_param_attrs(&mod->mkobj); 700 return err; 701 } 702 params = true; 703 } 704 705 if (!params) 706 return 0; 707 708 /* Create the param group. */ 709 err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp); 710 if (err) 711 free_module_param_attrs(&mod->mkobj); 712 return err; 713 } 714 715 /* 716 * module_param_sysfs_remove - remove sysfs support for one module 717 * @mod: module 718 * 719 * Remove sysfs entries for module parameters and the corresponding 720 * kobject. 721 */ 722 void module_param_sysfs_remove(struct module *mod) 723 { 724 if (mod->mkobj.mp) { 725 sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp); 726 /* We are positive that no one is using any param 727 * attrs at this point. Deallocate immediately. */ 728 free_module_param_attrs(&mod->mkobj); 729 } 730 } 731 #endif 732 733 void destroy_params(const struct kernel_param *params, unsigned num) 734 { 735 unsigned int i; 736 737 for (i = 0; i < num; i++) 738 if (params[i].ops->free) 739 params[i].ops->free(params[i].arg); 740 } 741 742 static struct module_kobject * __init locate_module_kobject(const char *name) 743 { 744 struct module_kobject *mk; 745 struct kobject *kobj; 746 int err; 747 748 kobj = kset_find_obj(module_kset, name); 749 if (kobj) { 750 mk = to_module_kobject(kobj); 751 } else { 752 mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL); 753 BUG_ON(!mk); 754 755 mk->mod = THIS_MODULE; 756 mk->kobj.kset = module_kset; 757 err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL, 758 "%s", name); 759 #ifdef CONFIG_MODULES 760 if (!err) 761 err = sysfs_create_file(&mk->kobj, &module_uevent.attr); 762 #endif 763 if (err) { 764 kobject_put(&mk->kobj); 765 pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n", 766 name, err); 767 return NULL; 768 } 769 770 /* So that we hold reference in both cases. */ 771 kobject_get(&mk->kobj); 772 } 773 774 return mk; 775 } 776 777 static void __init kernel_add_sysfs_param(const char *name, 778 const struct kernel_param *kparam, 779 unsigned int name_skip) 780 { 781 struct module_kobject *mk; 782 int err; 783 784 mk = locate_module_kobject(name); 785 if (!mk) 786 return; 787 788 /* We need to remove old parameters before adding more. */ 789 if (mk->mp) 790 sysfs_remove_group(&mk->kobj, &mk->mp->grp); 791 792 /* These should not fail at boot. */ 793 err = add_sysfs_param(mk, kparam, kparam->name + name_skip); 794 BUG_ON(err); 795 err = sysfs_create_group(&mk->kobj, &mk->mp->grp); 796 BUG_ON(err); 797 kobject_uevent(&mk->kobj, KOBJ_ADD); 798 kobject_put(&mk->kobj); 799 } 800 801 /* 802 * param_sysfs_builtin - add sysfs parameters for built-in modules 803 * 804 * Add module_parameters to sysfs for "modules" built into the kernel. 805 * 806 * The "module" name (KBUILD_MODNAME) is stored before a dot, the 807 * "parameter" name is stored behind a dot in kernel_param->name. So, 808 * extract the "module" name for all built-in kernel_param-eters, 809 * and for all who have the same, call kernel_add_sysfs_param. 810 */ 811 static void __init param_sysfs_builtin(void) 812 { 813 const struct kernel_param *kp; 814 unsigned int name_len; 815 char modname[MODULE_NAME_LEN]; 816 817 for (kp = __start___param; kp < __stop___param; kp++) { 818 char *dot; 819 820 if (kp->perm == 0) 821 continue; 822 823 dot = strchr(kp->name, '.'); 824 if (!dot) { 825 /* This happens for core_param() */ 826 strcpy(modname, "kernel"); 827 name_len = 0; 828 } else { 829 name_len = dot - kp->name + 1; 830 strlcpy(modname, kp->name, name_len); 831 } 832 kernel_add_sysfs_param(modname, kp, name_len); 833 } 834 } 835 836 ssize_t __modver_version_show(struct module_attribute *mattr, 837 struct module_kobject *mk, char *buf) 838 { 839 struct module_version_attribute *vattr = 840 container_of(mattr, struct module_version_attribute, mattr); 841 842 return scnprintf(buf, PAGE_SIZE, "%s\n", vattr->version); 843 } 844 845 extern const struct module_version_attribute *__start___modver[]; 846 extern const struct module_version_attribute *__stop___modver[]; 847 848 static void __init version_sysfs_builtin(void) 849 { 850 const struct module_version_attribute **p; 851 struct module_kobject *mk; 852 int err; 853 854 for (p = __start___modver; p < __stop___modver; p++) { 855 const struct module_version_attribute *vattr = *p; 856 857 mk = locate_module_kobject(vattr->module_name); 858 if (mk) { 859 err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr); 860 WARN_ON_ONCE(err); 861 kobject_uevent(&mk->kobj, KOBJ_ADD); 862 kobject_put(&mk->kobj); 863 } 864 } 865 } 866 867 /* module-related sysfs stuff */ 868 869 static ssize_t module_attr_show(struct kobject *kobj, 870 struct attribute *attr, 871 char *buf) 872 { 873 struct module_attribute *attribute; 874 struct module_kobject *mk; 875 int ret; 876 877 attribute = to_module_attr(attr); 878 mk = to_module_kobject(kobj); 879 880 if (!attribute->show) 881 return -EIO; 882 883 ret = attribute->show(attribute, mk, buf); 884 885 return ret; 886 } 887 888 static ssize_t module_attr_store(struct kobject *kobj, 889 struct attribute *attr, 890 const char *buf, size_t len) 891 { 892 struct module_attribute *attribute; 893 struct module_kobject *mk; 894 int ret; 895 896 attribute = to_module_attr(attr); 897 mk = to_module_kobject(kobj); 898 899 if (!attribute->store) 900 return -EIO; 901 902 ret = attribute->store(attribute, mk, buf, len); 903 904 return ret; 905 } 906 907 static const struct sysfs_ops module_sysfs_ops = { 908 .show = module_attr_show, 909 .store = module_attr_store, 910 }; 911 912 static int uevent_filter(struct kset *kset, struct kobject *kobj) 913 { 914 struct kobj_type *ktype = get_ktype(kobj); 915 916 if (ktype == &module_ktype) 917 return 1; 918 return 0; 919 } 920 921 static const struct kset_uevent_ops module_uevent_ops = { 922 .filter = uevent_filter, 923 }; 924 925 struct kset *module_kset; 926 int module_sysfs_initialized; 927 928 static void module_kobj_release(struct kobject *kobj) 929 { 930 struct module_kobject *mk = to_module_kobject(kobj); 931 complete(mk->kobj_completion); 932 } 933 934 struct kobj_type module_ktype = { 935 .release = module_kobj_release, 936 .sysfs_ops = &module_sysfs_ops, 937 }; 938 939 /* 940 * param_sysfs_init - wrapper for built-in params support 941 */ 942 static int __init param_sysfs_init(void) 943 { 944 module_kset = kset_create_and_add("module", &module_uevent_ops, NULL); 945 if (!module_kset) { 946 printk(KERN_WARNING "%s (%d): error creating kset\n", 947 __FILE__, __LINE__); 948 return -ENOMEM; 949 } 950 module_sysfs_initialized = 1; 951 952 version_sysfs_builtin(); 953 param_sysfs_builtin(); 954 955 return 0; 956 } 957 subsys_initcall(param_sysfs_init); 958 959 #endif /* CONFIG_SYSFS */ 960