1 /* $NetBSD: kern_module.c,v 1.13 2008/05/02 12:59:34 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /* 30 * Kernel module support. 31 * 32 * XXX Deps for loadable modules don't work, because we must load the 33 * module in order to find out which modules it requires. Linking may 34 * fail because of missing symbols. 35 */ 36 37 #include "opt_modular.h" 38 39 #include <sys/cdefs.h> 40 __KERNEL_RCSID(0, "$NetBSD: kern_module.c,v 1.13 2008/05/02 12:59:34 ad Exp $"); 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/fcntl.h> 45 #include <sys/proc.h> 46 #include <sys/kauth.h> 47 #include <sys/kobj.h> 48 #include <sys/kmem.h> 49 #include <sys/module.h> 50 #include <sys/syscall.h> 51 #include <sys/syscallargs.h> 52 53 #include <uvm/uvm_extern.h> 54 55 #include <machine/stdarg.h> 56 57 #ifndef LKM /* XXX */ 58 struct vm_map *lkm_map; 59 #endif 60 61 struct modlist module_list = TAILQ_HEAD_INITIALIZER(module_list); 62 struct modlist module_bootlist = TAILQ_HEAD_INITIALIZER(module_bootlist); 63 static module_t *module_active; 64 u_int module_count; 65 kmutex_t module_lock; 66 67 /* Ensure that the kernel's link set isn't empty. */ 68 static modinfo_t module_dummy; 69 __link_set_add_rodata(modules, module_dummy); 70 71 static module_t *module_lookup(const char *); 72 static int module_do_load(const char *, bool, int, prop_dictionary_t, 73 module_t **); 74 static int module_do_unload(const char *); 75 static void module_error(const char *, ...); 76 static int module_do_builtin(const char *, module_t **); 77 static int module_fetch_info(module_t *); 78 79 /* 80 * module_error: 81 * 82 * Utility function: log an error. 83 */ 84 static void 85 module_error(const char *fmt, ...) 86 { 87 va_list ap; 88 89 va_start(ap, fmt); 90 printf("WARNING: module error: "); 91 vprintf(fmt, ap); 92 printf("\n"); 93 va_end(ap); 94 } 95 96 /* 97 * module_init: 98 * 99 * Initialize the module subsystem. 100 */ 101 void 102 module_init(void) 103 { 104 extern struct vm_map *lkm_map; 105 106 if (lkm_map == NULL) 107 lkm_map = kernel_map; 108 mutex_init(&module_lock, MUTEX_DEFAULT, IPL_NONE); 109 #ifdef MODULAR /* XXX */ 110 module_init_md(); 111 #endif 112 } 113 114 /* 115 * module_init_class: 116 * 117 * Initialize all built-in and pre-loaded modules of the 118 * specified class. 119 */ 120 void 121 module_init_class(modclass_t class) 122 { 123 __link_set_decl(modules, modinfo_t); 124 modinfo_t *const *mip, *mi; 125 module_t *mod; 126 127 mutex_enter(&module_lock); 128 /* 129 * Builtins first. These can't depend on pre-loaded modules. 130 */ 131 __link_set_foreach(mip, modules) { 132 mi = *mip; 133 if (mi == &module_dummy) { 134 continue; 135 } 136 if (class != MODULE_CLASS_ANY && class != mi->mi_class) { 137 continue; 138 } 139 (void)module_do_builtin(mi->mi_name, NULL); 140 } 141 /* 142 * Now preloaded modules. These will be pulled off the 143 * list as we call module_do_load(); 144 */ 145 do { 146 TAILQ_FOREACH(mod, &module_bootlist, mod_chain) { 147 mi = mod->mod_info; 148 if (class != MODULE_CLASS_ANY && 149 class != mi->mi_class) 150 continue; 151 module_do_load(mi->mi_name, false, 0, NULL, NULL); 152 break; 153 } 154 } while (mod != NULL); 155 mutex_exit(&module_lock); 156 } 157 158 /* 159 * module_jettison: 160 * 161 * Return memory used by pre-loaded modules to the freelist. 162 */ 163 void 164 module_jettison(void) 165 { 166 167 /* XXX nothing yet */ 168 } 169 170 /* 171 * module_load: 172 * 173 * Load a single module from the file system. 174 */ 175 int 176 module_load(const char *filename, int flags, prop_dictionary_t props) 177 { 178 int error; 179 180 mutex_enter(&module_lock); 181 error = module_do_load(filename, false, flags, props, NULL); 182 mutex_exit(&module_lock); 183 184 return error; 185 } 186 187 /* 188 * module_unload: 189 * 190 * Find and unload a module by name. 191 */ 192 int 193 module_unload(const char *name) 194 { 195 int error; 196 197 mutex_enter(&module_lock); 198 error = module_do_unload(name); 199 mutex_exit(&module_lock); 200 201 return error; 202 } 203 204 /* 205 * module_lookup: 206 * 207 * Look up a module by name. 208 */ 209 module_t * 210 module_lookup(const char *name) 211 { 212 module_t *mod; 213 214 KASSERT(mutex_owned(&module_lock)); 215 216 TAILQ_FOREACH(mod, &module_list, mod_chain) { 217 if (strcmp(mod->mod_info->mi_name, name) == 0) { 218 break; 219 } 220 } 221 222 return mod; 223 } 224 225 /* 226 * module_hold: 227 * 228 * Add a single reference to a module. It's the caller's 229 * responsibility to ensure that the reference is dropped 230 * later. 231 */ 232 int 233 module_hold(const char *name) 234 { 235 module_t *mod; 236 237 mutex_enter(&module_lock); 238 mod = module_lookup(name); 239 if (mod == NULL) { 240 mutex_exit(&module_lock); 241 return ENOENT; 242 } 243 mod->mod_refcnt++; 244 mutex_exit(&module_lock); 245 246 return 0; 247 } 248 249 /* 250 * module_rele: 251 * 252 * Release a reference acquired with module_hold(). 253 */ 254 void 255 module_rele(const char *name) 256 { 257 module_t *mod; 258 259 mutex_enter(&module_lock); 260 mod = module_lookup(name); 261 if (mod == NULL) { 262 mutex_exit(&module_lock); 263 panic("module_rele: gone"); 264 } 265 mod->mod_refcnt--; 266 mutex_exit(&module_lock); 267 } 268 269 /* 270 * module_do_builtin: 271 * 272 * Initialize a single module from the list of modules that are 273 * built into the kernel (linked into the kernel image). 274 */ 275 static int 276 module_do_builtin(const char *name, module_t **modp) 277 { 278 __link_set_decl(modules, modinfo_t); 279 modinfo_t *const *mip; 280 const char *p, *s; 281 char buf[MAXMODNAME]; 282 modinfo_t *mi; 283 module_t *mod, *mod2; 284 size_t len; 285 int error, i; 286 287 KASSERT(mutex_owned(&module_lock)); 288 289 /* 290 * Check to see if already loaded. 291 */ 292 if ((mod = module_lookup(name)) != NULL) { 293 if (modp != NULL) { 294 *modp = mod; 295 } 296 return 0; 297 } 298 299 /* 300 * Search the list to see if we have a module by this name. 301 */ 302 error = ENOENT; 303 __link_set_foreach(mip, modules) { 304 mi = *mip; 305 if (mi == &module_dummy) { 306 continue; 307 } 308 if (strcmp(mi->mi_name, name) == 0) { 309 error = 0; 310 break; 311 } 312 } 313 if (error != 0) { 314 return error; 315 } 316 317 /* 318 * Initialize pre-requisites. 319 */ 320 mod = kmem_zalloc(sizeof(*mod), KM_SLEEP); 321 if (mod == NULL) { 322 return ENOMEM; 323 } 324 if (modp != NULL) { 325 *modp = mod; 326 } 327 if (mi->mi_required != NULL) { 328 for (s = mi->mi_required; *s != '\0'; s = p) { 329 if (*s == ',') 330 s++; 331 p = s; 332 while (*p != '\0' && *p != ',') 333 p++; 334 len = min(p - s + 1, sizeof(buf)); 335 strlcpy(buf, s, len); 336 if (buf[0] == '\0') 337 break; 338 if (mod->mod_nrequired == MAXMODDEPS - 1) { 339 module_error("too many required modules"); 340 kmem_free(mod, sizeof(*mod)); 341 return EINVAL; 342 } 343 error = module_do_builtin(buf, &mod2); 344 if (error != 0) { 345 kmem_free(mod, sizeof(*mod)); 346 return error; 347 } 348 mod->mod_required[mod->mod_nrequired++] = mod2; 349 } 350 } 351 352 /* 353 * Try to initialize the module. 354 */ 355 KASSERT(module_active == NULL); 356 module_active = mod; 357 error = (*mi->mi_modcmd)(MODULE_CMD_INIT, NULL); 358 module_active = NULL; 359 if (error != 0) { 360 module_error("builtin module `%s' " 361 "failed to init", mi->mi_name); 362 kmem_free(mod, sizeof(*mod)); 363 return error; 364 } 365 mod->mod_info = mi; 366 mod->mod_source = MODULE_SOURCE_KERNEL; 367 module_count++; 368 TAILQ_INSERT_TAIL(&module_list, mod, mod_chain); 369 370 /* 371 * If that worked, count dependencies. 372 */ 373 for (i = 0; i < mod->mod_nrequired; i++) { 374 mod->mod_required[i]->mod_refcnt++; 375 } 376 377 return 0; 378 } 379 380 /* 381 * module_do_load: 382 * 383 * Helper routine: load a module from the file system, or one 384 * pushed by the boot loader. 385 */ 386 static int 387 module_do_load(const char *filename, bool isdep, int flags, 388 prop_dictionary_t props, module_t **modp) 389 { 390 static TAILQ_HEAD(,module) pending = TAILQ_HEAD_INITIALIZER(pending); 391 static int depth; 392 const int maxdepth = 6; 393 modinfo_t *mi; 394 module_t *mod, *mod2; 395 char buf[MAXMODNAME]; 396 const char *s, *p; 397 int error; 398 size_t len; 399 u_int i; 400 bool closed = false; 401 402 KASSERT(mutex_owned(&module_lock)); 403 404 error = 0; 405 406 /* 407 * Avoid recursing too far. 408 */ 409 if (++depth > maxdepth) { 410 module_error("too many required modules"); 411 depth--; 412 return EMLINK; 413 } 414 415 /* 416 * Load the module and link. Before going to the file system, 417 * scan the list of modules loaded by the boot loader. Just 418 * before init is started the list of modules loaded at boot 419 * will be purged. Before init is started we can assume that 420 * `filename' is a module name and not a path name. 421 */ 422 TAILQ_FOREACH(mod, &module_bootlist, mod_chain) { 423 if (strcmp(mod->mod_info->mi_name, filename) == 0) { 424 TAILQ_REMOVE(&module_bootlist, mod, mod_chain); 425 break; 426 } 427 } 428 if (mod == NULL) { 429 mod = kmem_zalloc(sizeof(*mod), KM_SLEEP); 430 if (mod == NULL) { 431 depth--; 432 return ENOMEM; 433 } 434 error = kobj_open_file(&mod->mod_kobj, filename); 435 if (error != 0) { 436 kmem_free(mod, sizeof(*mod)); 437 depth--; 438 module_error("unable to open object file"); 439 return error; 440 } 441 error = kobj_load(mod->mod_kobj); 442 if (error != 0) { 443 kobj_close(mod->mod_kobj); 444 kmem_free(mod, sizeof(*mod)); 445 depth--; 446 module_error("unable to load kernel object"); 447 return error; 448 } 449 mod->mod_source = MODULE_SOURCE_FILESYS; 450 error = module_fetch_info(mod); 451 if (error != 0) { 452 goto fail; 453 } 454 } 455 TAILQ_INSERT_TAIL(&pending, mod, mod_chain); 456 457 /* 458 * Check compatibility. 459 */ 460 mi = mod->mod_info; 461 if (strlen(mi->mi_name) >= MAXMODNAME) { 462 error = EINVAL; 463 module_error("module name too long"); 464 goto fail; 465 } 466 467 /* 468 * If loading a dependency, `filename' is a plain module name. 469 * The name must match. 470 */ 471 if (isdep && strcmp(mi->mi_name, filename) != 0) { 472 error = ENOENT; 473 goto fail; 474 } 475 476 /* 477 * Check to see if the module is already loaded. If so, we may 478 * have been recursively called to handle a dependency, so be sure 479 * to set modp. 480 */ 481 if ((mod2 = module_lookup(mi->mi_name)) != NULL) { 482 if (modp != NULL) 483 *modp = mod2; 484 error = EEXIST; 485 goto fail; 486 } 487 488 /* 489 * Block circular dependencies. 490 */ 491 TAILQ_FOREACH(mod2, &pending, mod_chain) { 492 if (mod == mod2) { 493 continue; 494 } 495 if (strcmp(mod2->mod_info->mi_name, mi->mi_name) == 0) { 496 error = EDEADLK; 497 module_error("circular dependency detected"); 498 goto fail; 499 } 500 } 501 502 /* 503 * Pass proper name to kobj. This will register the module 504 * with the ksyms framework. 505 */ 506 error = kobj_set_name(mod->mod_kobj, mi->mi_name); 507 if (error != 0) { 508 module_error("unable to set name"); 509 goto fail; 510 } 511 512 /* 513 * Close the kobj before handling dependencies since we're done 514 * with it and don't want to open an already locked file if a 515 * circular dependency exists. 516 */ 517 kobj_close(mod->mod_kobj); 518 closed = true; 519 520 /* 521 * Now try to load any requisite modules. 522 */ 523 if (mi->mi_required != NULL) { 524 for (s = mi->mi_required; *s != '\0'; s = p) { 525 if (*s == ',') 526 s++; 527 p = s; 528 while (*p != '\0' && *p != ',') 529 p++; 530 len = p - s + 1; 531 if (len >= MAXMODNAME) { 532 error = EINVAL; 533 module_error("required module name too long"); 534 goto fail; 535 } 536 strlcpy(buf, s, len); 537 if (buf[0] == '\0') 538 break; 539 if (mod->mod_nrequired == MAXMODDEPS - 1) { 540 error = EINVAL; 541 module_error("too many required modules"); 542 goto fail; 543 } 544 if (strcmp(buf, mi->mi_name) == 0) { 545 error = EDEADLK; 546 module_error("self-dependency detected"); 547 goto fail; 548 } 549 error = module_do_load(buf, true, flags, NULL, 550 &mod->mod_required[mod->mod_nrequired++]); 551 if (error != 0 && error != EEXIST) 552 goto fail; 553 } 554 } 555 556 /* 557 * We loaded all needed modules successfully: initialize. 558 */ 559 KASSERT(module_active == NULL); 560 module_active = mod; 561 error = (*mi->mi_modcmd)(MODULE_CMD_INIT, props); 562 module_active = NULL; 563 if (error != 0) { 564 module_error("modctl function returned error %d", error); 565 goto fail; 566 } 567 568 /* 569 * Good, the module loaded successfully. Put it onto the 570 * list and add references to its requisite modules. 571 */ 572 module_count++; 573 if (!closed) 574 kobj_close(mod->mod_kobj); 575 TAILQ_REMOVE(&pending, mod, mod_chain); 576 TAILQ_INSERT_TAIL(&module_list, mod, mod_chain); 577 for (i = 0; i < mod->mod_nrequired; i++) { 578 KASSERT(mod->mod_required[i] != NULL); 579 mod->mod_required[i]->mod_refcnt++; 580 } 581 if (modp != NULL) { 582 *modp = mod; 583 } 584 depth--; 585 return 0; 586 587 fail: 588 if (!closed) 589 kobj_close(mod->mod_kobj); 590 TAILQ_REMOVE(&pending, mod, mod_chain); 591 kobj_unload(mod->mod_kobj); 592 kmem_free(mod, sizeof(*mod)); 593 depth--; 594 return error; 595 } 596 597 /* 598 * module_do_unload: 599 * 600 * Helper routine: do the dirty work of unloading a module. 601 */ 602 static int 603 module_do_unload(const char *name) 604 { 605 module_t *mod; 606 int error; 607 u_int i; 608 609 KASSERT(mutex_owned(&module_lock)); 610 611 mod = module_lookup(name); 612 if (mod == NULL) { 613 return ENOENT; 614 } 615 if (mod->mod_refcnt != 0 || mod->mod_source == MODULE_SOURCE_KERNEL) { 616 return EBUSY; 617 } 618 KASSERT(module_active == NULL); 619 module_active = mod; 620 error = (*mod->mod_info->mi_modcmd)(MODULE_CMD_FINI, NULL); 621 module_active = NULL; 622 if (error != 0) { 623 return error; 624 } 625 module_count--; 626 TAILQ_REMOVE(&module_list, mod, mod_chain); 627 for (i = 0; i < mod->mod_nrequired; i++) { 628 mod->mod_required[i]->mod_refcnt--; 629 } 630 if (mod->mod_kobj != NULL) { 631 kobj_unload(mod->mod_kobj); 632 } 633 kmem_free(mod, sizeof(*mod)); 634 635 return 0; 636 } 637 638 /* 639 * module_prime: 640 * 641 * Push a module loaded by the bootloader onto our internal 642 * list. 643 */ 644 int 645 module_prime(void *base, size_t size) 646 { 647 module_t *mod; 648 int error; 649 650 mod = kmem_zalloc(sizeof(*mod), KM_SLEEP); 651 if (mod == NULL) { 652 return ENOMEM; 653 } 654 mod->mod_source = MODULE_SOURCE_BOOT; 655 656 error = kobj_open_mem(&mod->mod_kobj, base, size); 657 if (error != 0) { 658 kmem_free(mod, sizeof(*mod)); 659 module_error("unable to open object pushed by boot loader"); 660 return error; 661 } 662 663 error = kobj_load(mod->mod_kobj); 664 if (error != 0) { 665 kobj_close(mod->mod_kobj); 666 kmem_free(mod, sizeof(*mod)); 667 module_error("unable to load object pushed by boot loader"); 668 return error; 669 } 670 error = module_fetch_info(mod); 671 if (error != 0) { 672 kobj_close(mod->mod_kobj); 673 kobj_unload(mod->mod_kobj); 674 kmem_free(mod, sizeof(*mod)); 675 module_error("unable to load object pushed by boot loader"); 676 return error; 677 } 678 679 TAILQ_INSERT_TAIL(&module_bootlist, mod, mod_chain); 680 681 return 0; 682 } 683 684 /* 685 * module_fetch_into: 686 * 687 * Fetch modinfo record from a loaded module. 688 */ 689 static int 690 module_fetch_info(module_t *mod) 691 { 692 int error; 693 void *addr; 694 size_t size; 695 696 /* 697 * Find module info record and check compatibility. 698 */ 699 error = kobj_find_section(mod->mod_kobj, "link_set_modules", 700 &addr, &size); 701 if (error != 0) { 702 module_error("`link_set_modules' section not present"); 703 return error; 704 } 705 if (size != sizeof(modinfo_t **)) { 706 module_error("`link_set_modules' section wrong size"); 707 return error; 708 } 709 mod->mod_info = *(modinfo_t **)addr; 710 711 return 0; 712 } 713 714 /* 715 * module_find_section: 716 * 717 * Allows a module that is being initialized to look up a section 718 * within its ELF object. 719 */ 720 int 721 module_find_section(const char *name, void **addr, size_t *size) 722 { 723 724 KASSERT(mutex_owned(&module_lock)); 725 KASSERT(module_active != NULL); 726 727 return kobj_find_section(module_active->mod_kobj, name, addr, size); 728 } 729