1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1998-2000 Doug Rabson 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 AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include "opt_ddb.h" 33 #include "opt_gdb.h" 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #ifdef GPROF 38 #include <sys/gmon.h> 39 #endif 40 #include <sys/kernel.h> 41 #include <sys/lock.h> 42 #include <sys/malloc.h> 43 #ifdef SPARSE_MAPPING 44 #include <sys/mman.h> 45 #endif 46 #include <sys/mutex.h> 47 #include <sys/mount.h> 48 #include <sys/pcpu.h> 49 #include <sys/proc.h> 50 #include <sys/namei.h> 51 #include <sys/fcntl.h> 52 #include <sys/vnode.h> 53 #include <sys/linker.h> 54 #include <sys/sysctl.h> 55 56 #include <machine/elf.h> 57 58 #include <net/vnet.h> 59 60 #include <security/mac/mac_framework.h> 61 62 #include <vm/vm.h> 63 #include <vm/vm_param.h> 64 #ifdef SPARSE_MAPPING 65 #include <vm/vm_object.h> 66 #include <vm/vm_kern.h> 67 #include <vm/vm_extern.h> 68 #endif 69 #include <vm/pmap.h> 70 #include <vm/vm_map.h> 71 72 #include <sys/link_elf.h> 73 74 #include "linker_if.h" 75 76 #define MAXSEGS 4 77 78 typedef struct elf_file { 79 struct linker_file lf; /* Common fields */ 80 int preloaded; /* Was file pre-loaded */ 81 caddr_t address; /* Relocation address */ 82 #ifdef SPARSE_MAPPING 83 vm_object_t object; /* VM object to hold file pages */ 84 #endif 85 Elf_Dyn *dynamic; /* Symbol table etc. */ 86 Elf_Hashelt nbuckets; /* DT_HASH info */ 87 Elf_Hashelt nchains; 88 const Elf_Hashelt *buckets; 89 const Elf_Hashelt *chains; 90 caddr_t hash; 91 caddr_t strtab; /* DT_STRTAB */ 92 int strsz; /* DT_STRSZ */ 93 const Elf_Sym *symtab; /* DT_SYMTAB */ 94 Elf_Addr *got; /* DT_PLTGOT */ 95 const Elf_Rel *pltrel; /* DT_JMPREL */ 96 int pltrelsize; /* DT_PLTRELSZ */ 97 const Elf_Rela *pltrela; /* DT_JMPREL */ 98 int pltrelasize; /* DT_PLTRELSZ */ 99 const Elf_Rel *rel; /* DT_REL */ 100 int relsize; /* DT_RELSZ */ 101 const Elf_Rela *rela; /* DT_RELA */ 102 int relasize; /* DT_RELASZ */ 103 caddr_t modptr; 104 const Elf_Sym *ddbsymtab; /* The symbol table we are using */ 105 long ddbsymcnt; /* Number of symbols */ 106 caddr_t ddbstrtab; /* String table */ 107 long ddbstrcnt; /* number of bytes in string table */ 108 caddr_t symbase; /* malloc'ed symbold base */ 109 caddr_t strbase; /* malloc'ed string base */ 110 caddr_t ctftab; /* CTF table */ 111 long ctfcnt; /* number of bytes in CTF table */ 112 caddr_t ctfoff; /* CTF offset table */ 113 caddr_t typoff; /* Type offset table */ 114 long typlen; /* Number of type entries. */ 115 Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */ 116 Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */ 117 Elf_Addr pcpu_base; /* Relocated pcpu set address. */ 118 #ifdef VIMAGE 119 Elf_Addr vnet_start; /* Pre-relocation vnet set start. */ 120 Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */ 121 Elf_Addr vnet_base; /* Relocated vnet set address. */ 122 #endif 123 #ifdef GDB 124 struct link_map gdb; /* hooks for gdb */ 125 #endif 126 } *elf_file_t; 127 128 struct elf_set { 129 Elf_Addr es_start; 130 Elf_Addr es_stop; 131 Elf_Addr es_base; 132 TAILQ_ENTRY(elf_set) es_link; 133 }; 134 135 TAILQ_HEAD(elf_set_head, elf_set); 136 137 #include <kern/kern_ctf.c> 138 139 static int link_elf_link_common_finish(linker_file_t); 140 static int link_elf_link_preload(linker_class_t cls, 141 const char *, linker_file_t *); 142 static int link_elf_link_preload_finish(linker_file_t); 143 static int link_elf_load_file(linker_class_t, const char *, 144 linker_file_t *); 145 static int link_elf_lookup_symbol(linker_file_t, const char *, 146 c_linker_sym_t *); 147 static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, 148 linker_symval_t *); 149 static int link_elf_search_symbol(linker_file_t, caddr_t, 150 c_linker_sym_t *, long *); 151 152 static void link_elf_unload_file(linker_file_t); 153 static void link_elf_unload_preload(linker_file_t); 154 static int link_elf_lookup_set(linker_file_t, const char *, 155 void ***, void ***, int *); 156 static int link_elf_each_function_name(linker_file_t, 157 int (*)(const char *, void *), void *); 158 static int link_elf_each_function_nameval(linker_file_t, 159 linker_function_nameval_callback_t, void *); 160 static void link_elf_reloc_local(linker_file_t); 161 static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); 162 static long link_elf_strtab_get(linker_file_t, caddr_t *); 163 static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *); 164 165 static kobj_method_t link_elf_methods[] = { 166 KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), 167 KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), 168 KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), 169 KOBJMETHOD(linker_unload, link_elf_unload_file), 170 KOBJMETHOD(linker_load_file, link_elf_load_file), 171 KOBJMETHOD(linker_link_preload, link_elf_link_preload), 172 KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), 173 KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), 174 KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), 175 KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval), 176 KOBJMETHOD(linker_ctf_get, link_elf_ctf_get), 177 KOBJMETHOD(linker_symtab_get, link_elf_symtab_get), 178 KOBJMETHOD(linker_strtab_get, link_elf_strtab_get), 179 KOBJMETHOD_END 180 }; 181 182 static struct linker_class link_elf_class = { 183 #if ELF_TARG_CLASS == ELFCLASS32 184 "elf32", 185 #else 186 "elf64", 187 #endif 188 link_elf_methods, sizeof(struct elf_file) 189 }; 190 191 typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase, 192 const void *data, int type, elf_lookup_fn lookup); 193 194 static int parse_dynamic(elf_file_t); 195 static int relocate_file(elf_file_t); 196 static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup, 197 elf_reloc_fn reloc, bool ifuncs); 198 static int link_elf_preload_parse_symbols(elf_file_t); 199 200 static struct elf_set_head set_pcpu_list; 201 #ifdef VIMAGE 202 static struct elf_set_head set_vnet_list; 203 #endif 204 205 static void 206 elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base) 207 { 208 struct elf_set *set, *iter; 209 210 set = malloc(sizeof(*set), M_LINKER, M_WAITOK); 211 set->es_start = start; 212 set->es_stop = stop; 213 set->es_base = base; 214 215 TAILQ_FOREACH(iter, list, es_link) { 216 KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) || 217 (set->es_start > iter->es_start && set->es_stop > iter->es_stop), 218 ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx", 219 (uintmax_t)set->es_start, (uintmax_t)set->es_stop, 220 (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop)); 221 222 if (iter->es_start > set->es_start) { 223 TAILQ_INSERT_BEFORE(iter, set, es_link); 224 break; 225 } 226 } 227 228 if (iter == NULL) 229 TAILQ_INSERT_TAIL(list, set, es_link); 230 } 231 232 static int 233 elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base) 234 { 235 struct elf_set *set; 236 237 TAILQ_FOREACH(set, list, es_link) { 238 if (addr < set->es_start) 239 return (0); 240 if (addr < set->es_stop) { 241 *start = set->es_start; 242 *base = set->es_base; 243 return (1); 244 } 245 } 246 247 return (0); 248 } 249 250 static void 251 elf_set_delete(struct elf_set_head *list, Elf_Addr start) 252 { 253 struct elf_set *set; 254 255 TAILQ_FOREACH(set, list, es_link) { 256 if (start < set->es_start) 257 break; 258 if (start == set->es_start) { 259 TAILQ_REMOVE(list, set, es_link); 260 free(set, M_LINKER); 261 return; 262 } 263 } 264 KASSERT(0, ("deleting unknown linker set (start = 0x%jx)", 265 (uintmax_t)start)); 266 } 267 268 #ifdef GDB 269 static void r_debug_state(struct r_debug *, struct link_map *); 270 271 /* 272 * A list of loaded modules for GDB to use for loading symbols. 273 */ 274 struct r_debug r_debug; 275 276 #define GDB_STATE(s) do { \ 277 r_debug.r_state = s; r_debug_state(NULL, NULL); \ 278 } while (0) 279 280 /* 281 * Function for the debugger to set a breakpoint on to gain control. 282 */ 283 static void 284 r_debug_state(struct r_debug *dummy_one __unused, 285 struct link_map *dummy_two __unused) 286 { 287 } 288 289 static void 290 link_elf_add_gdb(struct link_map *l) 291 { 292 struct link_map *prev; 293 294 l->l_next = NULL; 295 296 if (r_debug.r_map == NULL) { 297 /* Add first. */ 298 l->l_prev = NULL; 299 r_debug.r_map = l; 300 } else { 301 /* Append to list. */ 302 for (prev = r_debug.r_map; 303 prev->l_next != NULL; 304 prev = prev->l_next) 305 ; 306 l->l_prev = prev; 307 prev->l_next = l; 308 } 309 } 310 311 static void 312 link_elf_delete_gdb(struct link_map *l) 313 { 314 if (l->l_prev == NULL) { 315 /* Remove first. */ 316 if ((r_debug.r_map = l->l_next) != NULL) 317 l->l_next->l_prev = NULL; 318 } else { 319 /* Remove any but first. */ 320 if ((l->l_prev->l_next = l->l_next) != NULL) 321 l->l_next->l_prev = l->l_prev; 322 } 323 } 324 #endif /* GDB */ 325 326 /* 327 * The kernel symbol table starts here. 328 */ 329 extern struct _dynamic _DYNAMIC; 330 331 static void 332 link_elf_error(const char *filename, const char *s) 333 { 334 if (filename == NULL) 335 printf("kldload: %s\n", s); 336 else 337 printf("kldload: %s: %s\n", filename, s); 338 } 339 340 static void 341 link_elf_invoke_ctors(caddr_t addr, size_t size) 342 { 343 void (**ctor)(void); 344 size_t i, cnt; 345 346 if (addr == NULL || size == 0) 347 return; 348 cnt = size / sizeof(*ctor); 349 ctor = (void *)addr; 350 for (i = 0; i < cnt; i++) { 351 if (ctor[i] != NULL) 352 (*ctor[i])(); 353 } 354 } 355 356 /* 357 * Actions performed after linking/loading both the preloaded kernel and any 358 * modules; whether preloaded or dynamicly loaded. 359 */ 360 static int 361 link_elf_link_common_finish(linker_file_t lf) 362 { 363 #ifdef GDB 364 elf_file_t ef = (elf_file_t)lf; 365 char *newfilename; 366 #endif 367 int error; 368 369 /* Notify MD code that a module is being loaded. */ 370 error = elf_cpu_load_file(lf); 371 if (error != 0) 372 return (error); 373 374 #ifdef GDB 375 GDB_STATE(RT_ADD); 376 ef->gdb.l_addr = lf->address; 377 newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK); 378 strcpy(newfilename, lf->filename); 379 ef->gdb.l_name = newfilename; 380 ef->gdb.l_ld = ef->dynamic; 381 link_elf_add_gdb(&ef->gdb); 382 GDB_STATE(RT_CONSISTENT); 383 #endif 384 385 /* Invoke .ctors */ 386 link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); 387 return (0); 388 } 389 390 #ifdef RELOCATABLE_KERNEL 391 /* 392 * __startkernel and __endkernel are symbols set up as relocation canaries. 393 * 394 * They are defined in locore to reference linker script symbols at the 395 * beginning and end of the LOAD area. This has the desired side effect of 396 * giving us variables that have relative relocations pointing at them, so 397 * relocation of the kernel object will cause the variables to be updated 398 * automatically by the runtime linker when we initialize. 399 * 400 * There are two main reasons to relocate the kernel: 401 * 1) If the loader needed to load the kernel at an alternate load address. 402 * 2) If the kernel is switching address spaces on machines like POWER9 403 * under Radix where the high bits of the effective address are used to 404 * differentiate between hypervisor, host, guest, and problem state. 405 */ 406 extern vm_offset_t __startkernel, __endkernel; 407 #endif 408 409 static unsigned long kern_relbase = KERNBASE; 410 411 SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD, 412 SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address"); 413 SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD, 414 &kern_relbase, 0, "Kernel relocated base address"); 415 416 static void 417 link_elf_init(void* arg) 418 { 419 Elf_Dyn *dp; 420 Elf_Addr *ctors_addrp; 421 Elf_Size *ctors_sizep; 422 caddr_t modptr, baseptr, sizeptr; 423 elf_file_t ef; 424 const char *modname; 425 426 linker_add_class(&link_elf_class); 427 428 dp = (Elf_Dyn *)&_DYNAMIC; 429 modname = NULL; 430 modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel"); 431 if (modptr == NULL) 432 modptr = preload_search_by_type("elf kernel"); 433 modname = (char *)preload_search_info(modptr, MODINFO_NAME); 434 if (modname == NULL) 435 modname = "kernel"; 436 linker_kernel_file = linker_make_file(modname, &link_elf_class); 437 if (linker_kernel_file == NULL) 438 panic("%s: Can't create linker structures for kernel", 439 __func__); 440 441 ef = (elf_file_t) linker_kernel_file; 442 ef->preloaded = 1; 443 #ifdef RELOCATABLE_KERNEL 444 /* Compute relative displacement */ 445 ef->address = (caddr_t) (__startkernel - KERNBASE); 446 #else 447 ef->address = 0; 448 #endif 449 #ifdef SPARSE_MAPPING 450 ef->object = NULL; 451 #endif 452 ef->dynamic = dp; 453 454 if (dp != NULL) 455 parse_dynamic(ef); 456 #ifdef RELOCATABLE_KERNEL 457 linker_kernel_file->address = (caddr_t)__startkernel; 458 linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel); 459 kern_relbase = (unsigned long)__startkernel; 460 #else 461 linker_kernel_file->address += KERNBASE; 462 linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; 463 #endif 464 465 if (modptr != NULL) { 466 ef->modptr = modptr; 467 baseptr = preload_search_info(modptr, MODINFO_ADDR); 468 if (baseptr != NULL) 469 linker_kernel_file->address = *(caddr_t *)baseptr; 470 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 471 if (sizeptr != NULL) 472 linker_kernel_file->size = *(size_t *)sizeptr; 473 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 474 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 475 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 476 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 477 if (ctors_addrp != NULL && ctors_sizep != NULL) { 478 linker_kernel_file->ctors_addr = ef->address + 479 *ctors_addrp; 480 linker_kernel_file->ctors_size = *ctors_sizep; 481 } 482 } 483 (void)link_elf_preload_parse_symbols(ef); 484 485 #ifdef GDB 486 r_debug.r_map = NULL; 487 r_debug.r_brk = r_debug_state; 488 r_debug.r_state = RT_CONSISTENT; 489 #endif 490 491 (void)link_elf_link_common_finish(linker_kernel_file); 492 linker_kernel_file->flags |= LINKER_FILE_LINKED; 493 TAILQ_INIT(&set_pcpu_list); 494 #ifdef VIMAGE 495 TAILQ_INIT(&set_vnet_list); 496 #endif 497 } 498 499 SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL); 500 501 static int 502 link_elf_preload_parse_symbols(elf_file_t ef) 503 { 504 caddr_t pointer; 505 caddr_t ssym, esym, base; 506 caddr_t strtab; 507 int strcnt; 508 Elf_Sym *symtab; 509 int symcnt; 510 511 if (ef->modptr == NULL) 512 return (0); 513 pointer = preload_search_info(ef->modptr, 514 MODINFO_METADATA | MODINFOMD_SSYM); 515 if (pointer == NULL) 516 return (0); 517 ssym = *(caddr_t *)pointer; 518 pointer = preload_search_info(ef->modptr, 519 MODINFO_METADATA | MODINFOMD_ESYM); 520 if (pointer == NULL) 521 return (0); 522 esym = *(caddr_t *)pointer; 523 524 base = ssym; 525 526 symcnt = *(long *)base; 527 base += sizeof(long); 528 symtab = (Elf_Sym *)base; 529 base += roundup(symcnt, sizeof(long)); 530 531 if (base > esym || base < ssym) { 532 printf("Symbols are corrupt!\n"); 533 return (EINVAL); 534 } 535 536 strcnt = *(long *)base; 537 base += sizeof(long); 538 strtab = base; 539 base += roundup(strcnt, sizeof(long)); 540 541 if (base > esym || base < ssym) { 542 printf("Symbols are corrupt!\n"); 543 return (EINVAL); 544 } 545 546 ef->ddbsymtab = symtab; 547 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 548 ef->ddbstrtab = strtab; 549 ef->ddbstrcnt = strcnt; 550 551 return (0); 552 } 553 554 static int 555 parse_dynamic(elf_file_t ef) 556 { 557 Elf_Dyn *dp; 558 int plttype = DT_REL; 559 560 for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { 561 switch (dp->d_tag) { 562 case DT_HASH: 563 { 564 /* From src/libexec/rtld-elf/rtld.c */ 565 const Elf_Hashelt *hashtab = (const Elf_Hashelt *) 566 (ef->address + dp->d_un.d_ptr); 567 ef->nbuckets = hashtab[0]; 568 ef->nchains = hashtab[1]; 569 ef->buckets = hashtab + 2; 570 ef->chains = ef->buckets + ef->nbuckets; 571 break; 572 } 573 case DT_STRTAB: 574 ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); 575 break; 576 case DT_STRSZ: 577 ef->strsz = dp->d_un.d_val; 578 break; 579 case DT_SYMTAB: 580 ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); 581 break; 582 case DT_SYMENT: 583 if (dp->d_un.d_val != sizeof(Elf_Sym)) 584 return (ENOEXEC); 585 break; 586 case DT_PLTGOT: 587 ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); 588 break; 589 case DT_REL: 590 ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 591 break; 592 case DT_RELSZ: 593 ef->relsize = dp->d_un.d_val; 594 break; 595 case DT_RELENT: 596 if (dp->d_un.d_val != sizeof(Elf_Rel)) 597 return (ENOEXEC); 598 break; 599 case DT_JMPREL: 600 ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); 601 break; 602 case DT_PLTRELSZ: 603 ef->pltrelsize = dp->d_un.d_val; 604 break; 605 case DT_RELA: 606 ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); 607 break; 608 case DT_RELASZ: 609 ef->relasize = dp->d_un.d_val; 610 break; 611 case DT_RELAENT: 612 if (dp->d_un.d_val != sizeof(Elf_Rela)) 613 return (ENOEXEC); 614 break; 615 case DT_PLTREL: 616 plttype = dp->d_un.d_val; 617 if (plttype != DT_REL && plttype != DT_RELA) 618 return (ENOEXEC); 619 break; 620 #ifdef GDB 621 case DT_DEBUG: 622 dp->d_un.d_ptr = (Elf_Addr)&r_debug; 623 break; 624 #endif 625 } 626 } 627 628 if (plttype == DT_RELA) { 629 ef->pltrela = (const Elf_Rela *)ef->pltrel; 630 ef->pltrel = NULL; 631 ef->pltrelasize = ef->pltrelsize; 632 ef->pltrelsize = 0; 633 } 634 635 ef->ddbsymtab = ef->symtab; 636 ef->ddbsymcnt = ef->nchains; 637 ef->ddbstrtab = ef->strtab; 638 ef->ddbstrcnt = ef->strsz; 639 640 return elf_cpu_parse_dynamic(ef->address, ef->dynamic); 641 } 642 643 #define LS_PADDING 0x90909090 644 static int 645 parse_dpcpu(elf_file_t ef) 646 { 647 int error, size; 648 #if defined(__i386__) 649 uint32_t pad; 650 #endif 651 652 ef->pcpu_start = 0; 653 ef->pcpu_stop = 0; 654 error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start, 655 (void ***)&ef->pcpu_stop, NULL); 656 /* Error just means there is no pcpu set to relocate. */ 657 if (error != 0) 658 return (0); 659 size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start; 660 /* Empty set? */ 661 if (size < 1) 662 return (0); 663 #if defined(__i386__) 664 /* In case we do find __start/stop_set_ symbols double-check. */ 665 if (size < 4) { 666 uprintf("Kernel module '%s' must be recompiled with " 667 "linker script\n", ef->lf.pathname); 668 return (ENOEXEC); 669 } 670 671 /* Padding from linker-script correct? */ 672 pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad)); 673 if (pad != LS_PADDING) { 674 uprintf("Kernel module '%s' must be recompiled with " 675 "linker script, invalid padding %#04x (%#04x)\n", 676 ef->lf.pathname, pad, LS_PADDING); 677 return (ENOEXEC); 678 } 679 /* If we only have valid padding, nothing to do. */ 680 if (size == 4) 681 return (0); 682 #endif 683 /* 684 * Allocate space in the primary pcpu area. Copy in our 685 * initialization from the data section and then initialize 686 * all per-cpu storage from that. 687 */ 688 ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size); 689 if (ef->pcpu_base == 0) { 690 printf("%s: pcpu module space is out of space; " 691 "cannot allocate %d for %s\n", 692 __func__, size, ef->lf.pathname); 693 return (ENOSPC); 694 } 695 memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size); 696 dpcpu_copy((void *)ef->pcpu_base, size); 697 elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop, 698 ef->pcpu_base); 699 700 return (0); 701 } 702 703 #ifdef VIMAGE 704 static int 705 parse_vnet(elf_file_t ef) 706 { 707 int error, size; 708 #if defined(__i386__) 709 uint32_t pad; 710 #endif 711 712 ef->vnet_start = 0; 713 ef->vnet_stop = 0; 714 error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start, 715 (void ***)&ef->vnet_stop, NULL); 716 /* Error just means there is no vnet data set to relocate. */ 717 if (error != 0) 718 return (0); 719 size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start; 720 /* Empty set? */ 721 if (size < 1) 722 return (0); 723 #if defined(__i386__) 724 /* In case we do find __start/stop_set_ symbols double-check. */ 725 if (size < 4) { 726 uprintf("Kernel module '%s' must be recompiled with " 727 "linker script\n", ef->lf.pathname); 728 return (ENOEXEC); 729 } 730 731 /* Padding from linker-script correct? */ 732 pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad)); 733 if (pad != LS_PADDING) { 734 uprintf("Kernel module '%s' must be recompiled with " 735 "linker script, invalid padding %#04x (%#04x)\n", 736 ef->lf.pathname, pad, LS_PADDING); 737 return (ENOEXEC); 738 } 739 /* If we only have valid padding, nothing to do. */ 740 if (size == 4) 741 return (0); 742 #endif 743 /* 744 * Allocate space in the primary vnet area. Copy in our 745 * initialization from the data section and then initialize 746 * all per-vnet storage from that. 747 */ 748 ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size); 749 if (ef->vnet_base == 0) { 750 printf("%s: vnet module space is out of space; " 751 "cannot allocate %d for %s\n", 752 __func__, size, ef->lf.pathname); 753 return (ENOSPC); 754 } 755 memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size); 756 vnet_data_copy((void *)ef->vnet_base, size); 757 elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop, 758 ef->vnet_base); 759 760 return (0); 761 } 762 #endif 763 #undef LS_PADDING 764 765 /* 766 * Apply the specified protection to the loadable segments of a preloaded linker 767 * file. 768 */ 769 static int 770 preload_protect(elf_file_t ef, vm_prot_t prot) 771 { 772 #ifdef __amd64__ 773 Elf_Ehdr *hdr; 774 Elf_Phdr *phdr, *phlimit; 775 vm_prot_t nprot; 776 int error; 777 778 error = 0; 779 hdr = (Elf_Ehdr *)ef->address; 780 phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff); 781 phlimit = phdr + hdr->e_phnum; 782 for (; phdr < phlimit; phdr++) { 783 if (phdr->p_type != PT_LOAD) 784 continue; 785 786 nprot = prot | VM_PROT_READ; 787 if ((phdr->p_flags & PF_W) != 0) 788 nprot |= VM_PROT_WRITE; 789 if ((phdr->p_flags & PF_X) != 0) 790 nprot |= VM_PROT_EXECUTE; 791 error = pmap_change_prot((vm_offset_t)ef->address + 792 phdr->p_vaddr, round_page(phdr->p_memsz), nprot); 793 if (error != 0) 794 break; 795 } 796 return (error); 797 #else 798 return (0); 799 #endif 800 } 801 802 #ifdef __arm__ 803 /* 804 * Locate the ARM exception/unwind table info for DDB and stack(9) use by 805 * searching for the section header that describes it. There may be no unwind 806 * info, for example in a module containing only data. 807 */ 808 static void 809 link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr) 810 { 811 int i; 812 813 for (i = 0; i < nhdr; i++) { 814 if (shdr[i].sh_type == SHT_ARM_EXIDX) { 815 lf->exidx_addr = shdr[i].sh_addr + lf->address; 816 lf->exidx_size = shdr[i].sh_size; 817 break; 818 } 819 } 820 } 821 822 /* 823 * Locate the section headers metadata in a preloaded module, then use it to 824 * locate the exception/unwind table in the module. The size of the metadata 825 * block is stored in a uint32 word immediately before the data itself, and a 826 * comment in preload_search_info() says it is safe to rely on that. 827 */ 828 static void 829 link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr) 830 { 831 uint32_t *modinfo; 832 Elf_Shdr *shdr; 833 uint32_t nhdr; 834 835 modinfo = (uint32_t *)preload_search_info(modptr, 836 MODINFO_METADATA | MODINFOMD_SHDR); 837 if (modinfo != NULL) { 838 shdr = (Elf_Shdr *)modinfo; 839 nhdr = modinfo[-1] / sizeof(Elf_Shdr); 840 link_elf_locate_exidx(lf, shdr, nhdr); 841 } 842 } 843 844 #endif /* __arm__ */ 845 846 static int 847 link_elf_link_preload(linker_class_t cls, const char *filename, 848 linker_file_t *result) 849 { 850 Elf_Addr *ctors_addrp; 851 Elf_Size *ctors_sizep; 852 caddr_t modptr, baseptr, sizeptr, dynptr; 853 char *type; 854 elf_file_t ef; 855 linker_file_t lf; 856 int error; 857 vm_offset_t dp; 858 859 /* Look to see if we have the file preloaded */ 860 modptr = preload_search_by_name(filename); 861 if (modptr == NULL) 862 return (ENOENT); 863 864 type = (char *)preload_search_info(modptr, MODINFO_TYPE); 865 baseptr = preload_search_info(modptr, MODINFO_ADDR); 866 sizeptr = preload_search_info(modptr, MODINFO_SIZE); 867 dynptr = preload_search_info(modptr, 868 MODINFO_METADATA | MODINFOMD_DYNAMIC); 869 if (type == NULL || 870 (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 && 871 strcmp(type, "elf module") != 0)) 872 return (EFTYPE); 873 if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) 874 return (EINVAL); 875 876 lf = linker_make_file(filename, &link_elf_class); 877 if (lf == NULL) 878 return (ENOMEM); 879 880 ef = (elf_file_t) lf; 881 ef->preloaded = 1; 882 ef->modptr = modptr; 883 ef->address = *(caddr_t *)baseptr; 884 #ifdef SPARSE_MAPPING 885 ef->object = NULL; 886 #endif 887 dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; 888 ef->dynamic = (Elf_Dyn *)dp; 889 lf->address = ef->address; 890 lf->size = *(size_t *)sizeptr; 891 892 ctors_addrp = (Elf_Addr *)preload_search_info(modptr, 893 MODINFO_METADATA | MODINFOMD_CTORS_ADDR); 894 ctors_sizep = (Elf_Size *)preload_search_info(modptr, 895 MODINFO_METADATA | MODINFOMD_CTORS_SIZE); 896 if (ctors_addrp != NULL && ctors_sizep != NULL) { 897 lf->ctors_addr = ef->address + *ctors_addrp; 898 lf->ctors_size = *ctors_sizep; 899 } 900 901 #ifdef __arm__ 902 link_elf_locate_exidx_preload(lf, modptr); 903 #endif 904 905 error = parse_dynamic(ef); 906 if (error == 0) 907 error = parse_dpcpu(ef); 908 #ifdef VIMAGE 909 if (error == 0) 910 error = parse_vnet(ef); 911 #endif 912 if (error == 0) 913 error = preload_protect(ef, VM_PROT_ALL); 914 if (error != 0) { 915 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 916 return (error); 917 } 918 link_elf_reloc_local(lf); 919 *result = lf; 920 return (0); 921 } 922 923 static int 924 link_elf_link_preload_finish(linker_file_t lf) 925 { 926 elf_file_t ef; 927 int error; 928 929 ef = (elf_file_t) lf; 930 error = relocate_file(ef); 931 if (error == 0) 932 error = preload_protect(ef, VM_PROT_NONE); 933 if (error != 0) 934 return (error); 935 (void)link_elf_preload_parse_symbols(ef); 936 937 return (link_elf_link_common_finish(lf)); 938 } 939 940 static int 941 link_elf_load_file(linker_class_t cls, const char* filename, 942 linker_file_t* result) 943 { 944 struct nameidata nd; 945 struct thread* td = curthread; /* XXX */ 946 Elf_Ehdr *hdr; 947 caddr_t firstpage, segbase; 948 int nbytes, i; 949 Elf_Phdr *phdr; 950 Elf_Phdr *phlimit; 951 Elf_Phdr *segs[MAXSEGS]; 952 int nsegs; 953 Elf_Phdr *phdyn; 954 caddr_t mapbase; 955 size_t mapsize; 956 Elf_Addr base_vaddr; 957 Elf_Addr base_vlimit; 958 int error = 0; 959 ssize_t resid; 960 int flags; 961 elf_file_t ef; 962 linker_file_t lf; 963 Elf_Shdr *shdr; 964 int symtabindex; 965 int symstrindex; 966 int shstrindex; 967 int symcnt; 968 int strcnt; 969 char *shstrs; 970 971 shdr = NULL; 972 lf = NULL; 973 shstrs = NULL; 974 975 NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, td); 976 flags = FREAD; 977 error = vn_open(&nd, &flags, 0, NULL); 978 if (error != 0) 979 return (error); 980 NDFREE(&nd, NDF_ONLY_PNBUF); 981 if (nd.ni_vp->v_type != VREG) { 982 error = ENOEXEC; 983 firstpage = NULL; 984 goto out; 985 } 986 #ifdef MAC 987 error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp); 988 if (error != 0) { 989 firstpage = NULL; 990 goto out; 991 } 992 #endif 993 994 /* 995 * Read the elf header from the file. 996 */ 997 firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); 998 hdr = (Elf_Ehdr *)firstpage; 999 error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, 1000 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1001 &resid, td); 1002 nbytes = PAGE_SIZE - resid; 1003 if (error != 0) 1004 goto out; 1005 1006 if (!IS_ELF(*hdr)) { 1007 error = ENOEXEC; 1008 goto out; 1009 } 1010 1011 if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || 1012 hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { 1013 link_elf_error(filename, "Unsupported file layout"); 1014 error = ENOEXEC; 1015 goto out; 1016 } 1017 if (hdr->e_ident[EI_VERSION] != EV_CURRENT || 1018 hdr->e_version != EV_CURRENT) { 1019 link_elf_error(filename, "Unsupported file version"); 1020 error = ENOEXEC; 1021 goto out; 1022 } 1023 if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { 1024 error = ENOSYS; 1025 goto out; 1026 } 1027 if (hdr->e_machine != ELF_TARG_MACH) { 1028 link_elf_error(filename, "Unsupported machine"); 1029 error = ENOEXEC; 1030 goto out; 1031 } 1032 1033 /* 1034 * We rely on the program header being in the first page. 1035 * This is not strictly required by the ABI specification, but 1036 * it seems to always true in practice. And, it simplifies 1037 * things considerably. 1038 */ 1039 if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && 1040 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && 1041 (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) 1042 link_elf_error(filename, "Unreadable program headers"); 1043 1044 /* 1045 * Scan the program header entries, and save key information. 1046 * 1047 * We rely on there being exactly two load segments, text and data, 1048 * in that order. 1049 */ 1050 phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); 1051 phlimit = phdr + hdr->e_phnum; 1052 nsegs = 0; 1053 phdyn = NULL; 1054 while (phdr < phlimit) { 1055 switch (phdr->p_type) { 1056 case PT_LOAD: 1057 if (nsegs == MAXSEGS) { 1058 link_elf_error(filename, "Too many sections"); 1059 error = ENOEXEC; 1060 goto out; 1061 } 1062 /* 1063 * XXX: We just trust they come in right order ?? 1064 */ 1065 segs[nsegs] = phdr; 1066 ++nsegs; 1067 break; 1068 1069 case PT_DYNAMIC: 1070 phdyn = phdr; 1071 break; 1072 1073 case PT_INTERP: 1074 error = ENOSYS; 1075 goto out; 1076 } 1077 1078 ++phdr; 1079 } 1080 if (phdyn == NULL) { 1081 link_elf_error(filename, "Object is not dynamically-linked"); 1082 error = ENOEXEC; 1083 goto out; 1084 } 1085 if (nsegs == 0) { 1086 link_elf_error(filename, "No sections"); 1087 error = ENOEXEC; 1088 goto out; 1089 } 1090 1091 /* 1092 * Allocate the entire address space of the object, to stake 1093 * out our contiguous region, and to establish the base 1094 * address for relocation. 1095 */ 1096 base_vaddr = trunc_page(segs[0]->p_vaddr); 1097 base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + 1098 segs[nsegs - 1]->p_memsz); 1099 mapsize = base_vlimit - base_vaddr; 1100 1101 lf = linker_make_file(filename, &link_elf_class); 1102 if (lf == NULL) { 1103 error = ENOMEM; 1104 goto out; 1105 } 1106 1107 ef = (elf_file_t) lf; 1108 #ifdef SPARSE_MAPPING 1109 ef->object = vm_object_allocate(OBJT_PHYS, atop(mapsize)); 1110 if (ef->object == NULL) { 1111 error = ENOMEM; 1112 goto out; 1113 } 1114 #ifdef __amd64__ 1115 mapbase = (caddr_t)KERNBASE; 1116 #else 1117 mapbase = (caddr_t)vm_map_min(kernel_map); 1118 #endif 1119 /* 1120 * Mapping protections are downgraded after relocation processing. 1121 */ 1122 error = vm_map_find(kernel_map, ef->object, 0, 1123 (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE, 1124 VM_PROT_ALL, VM_PROT_ALL, 0); 1125 if (error != 0) { 1126 vm_object_deallocate(ef->object); 1127 ef->object = NULL; 1128 goto out; 1129 } 1130 #else 1131 mapbase = malloc(mapsize, M_LINKER, M_EXEC | M_WAITOK); 1132 #endif 1133 ef->address = mapbase; 1134 1135 /* 1136 * Read the text and data sections and zero the bss. 1137 */ 1138 for (i = 0; i < nsegs; i++) { 1139 segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 1140 1141 #ifdef SPARSE_MAPPING 1142 /* 1143 * Consecutive segments may have different mapping permissions, 1144 * so be strict and verify that their mappings do not overlap. 1145 */ 1146 if (((vm_offset_t)segbase & PAGE_MASK) != 0) { 1147 error = EINVAL; 1148 goto out; 1149 } 1150 1151 error = vm_map_wire(kernel_map, 1152 (vm_offset_t)segbase, 1153 (vm_offset_t)segbase + round_page(segs[i]->p_memsz), 1154 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); 1155 if (error != KERN_SUCCESS) { 1156 error = ENOMEM; 1157 goto out; 1158 } 1159 #endif 1160 1161 error = vn_rdwr(UIO_READ, nd.ni_vp, 1162 segbase, segs[i]->p_filesz, segs[i]->p_offset, 1163 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1164 &resid, td); 1165 if (error != 0) 1166 goto out; 1167 bzero(segbase + segs[i]->p_filesz, 1168 segs[i]->p_memsz - segs[i]->p_filesz); 1169 } 1170 1171 #ifdef GPROF 1172 /* Update profiling information with the new text segment. */ 1173 mtx_lock(&Giant); 1174 kmupetext((uintfptr_t)(mapbase + segs[0]->p_vaddr - base_vaddr + 1175 segs[0]->p_memsz)); 1176 mtx_unlock(&Giant); 1177 #endif 1178 1179 ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); 1180 1181 lf->address = ef->address; 1182 lf->size = mapsize; 1183 1184 error = parse_dynamic(ef); 1185 if (error != 0) 1186 goto out; 1187 error = parse_dpcpu(ef); 1188 if (error != 0) 1189 goto out; 1190 #ifdef VIMAGE 1191 error = parse_vnet(ef); 1192 if (error != 0) 1193 goto out; 1194 #endif 1195 link_elf_reloc_local(lf); 1196 1197 VOP_UNLOCK(nd.ni_vp); 1198 error = linker_load_dependencies(lf); 1199 vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); 1200 if (error != 0) 1201 goto out; 1202 error = relocate_file(ef); 1203 if (error != 0) 1204 goto out; 1205 1206 #ifdef SPARSE_MAPPING 1207 /* 1208 * Downgrade permissions on text segment mappings now that relocation 1209 * processing is complete. Restrict permissions on read-only segments. 1210 */ 1211 for (i = 0; i < nsegs; i++) { 1212 vm_prot_t prot; 1213 1214 if (segs[i]->p_type != PT_LOAD) 1215 continue; 1216 1217 prot = VM_PROT_READ; 1218 if ((segs[i]->p_flags & PF_W) != 0) 1219 prot |= VM_PROT_WRITE; 1220 if ((segs[i]->p_flags & PF_X) != 0) 1221 prot |= VM_PROT_EXECUTE; 1222 segbase = mapbase + segs[i]->p_vaddr - base_vaddr; 1223 error = vm_map_protect(kernel_map, 1224 (vm_offset_t)segbase, 1225 (vm_offset_t)segbase + round_page(segs[i]->p_memsz), 1226 prot, FALSE); 1227 if (error != KERN_SUCCESS) { 1228 error = ENOMEM; 1229 goto out; 1230 } 1231 } 1232 #endif 1233 1234 /* 1235 * Try and load the symbol table if it's present. (you can 1236 * strip it!) 1237 */ 1238 nbytes = hdr->e_shnum * hdr->e_shentsize; 1239 if (nbytes == 0 || hdr->e_shoff == 0) 1240 goto nosyms; 1241 shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1242 error = vn_rdwr(UIO_READ, nd.ni_vp, 1243 (caddr_t)shdr, nbytes, hdr->e_shoff, 1244 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1245 &resid, td); 1246 if (error != 0) 1247 goto out; 1248 1249 /* Read section string table */ 1250 shstrindex = hdr->e_shstrndx; 1251 if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB && 1252 shdr[shstrindex].sh_size != 0) { 1253 nbytes = shdr[shstrindex].sh_size; 1254 shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); 1255 error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes, 1256 shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, 1257 td->td_ucred, NOCRED, &resid, td); 1258 if (error) 1259 goto out; 1260 } 1261 1262 symtabindex = -1; 1263 symstrindex = -1; 1264 for (i = 0; i < hdr->e_shnum; i++) { 1265 if (shdr[i].sh_type == SHT_SYMTAB) { 1266 symtabindex = i; 1267 symstrindex = shdr[i].sh_link; 1268 } else if (shstrs != NULL && shdr[i].sh_name != 0 && 1269 strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) { 1270 /* Record relocated address and size of .ctors. */ 1271 lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr; 1272 lf->ctors_size = shdr[i].sh_size; 1273 } 1274 } 1275 if (symtabindex < 0 || symstrindex < 0) 1276 goto nosyms; 1277 1278 symcnt = shdr[symtabindex].sh_size; 1279 ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); 1280 strcnt = shdr[symstrindex].sh_size; 1281 ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); 1282 1283 error = vn_rdwr(UIO_READ, nd.ni_vp, 1284 ef->symbase, symcnt, shdr[symtabindex].sh_offset, 1285 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1286 &resid, td); 1287 if (error != 0) 1288 goto out; 1289 error = vn_rdwr(UIO_READ, nd.ni_vp, 1290 ef->strbase, strcnt, shdr[symstrindex].sh_offset, 1291 UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, 1292 &resid, td); 1293 if (error != 0) 1294 goto out; 1295 1296 ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); 1297 ef->ddbsymtab = (const Elf_Sym *)ef->symbase; 1298 ef->ddbstrcnt = strcnt; 1299 ef->ddbstrtab = ef->strbase; 1300 1301 nosyms: 1302 1303 #ifdef __arm__ 1304 link_elf_locate_exidx(lf, shdr, hdr->e_shnum); 1305 #endif 1306 1307 error = link_elf_link_common_finish(lf); 1308 if (error != 0) 1309 goto out; 1310 1311 *result = lf; 1312 1313 out: 1314 VOP_UNLOCK(nd.ni_vp); 1315 vn_close(nd.ni_vp, FREAD, td->td_ucred, td); 1316 if (error != 0 && lf != NULL) 1317 linker_file_unload(lf, LINKER_UNLOAD_FORCE); 1318 free(shdr, M_LINKER); 1319 free(firstpage, M_LINKER); 1320 free(shstrs, M_LINKER); 1321 1322 return (error); 1323 } 1324 1325 Elf_Addr 1326 elf_relocaddr(linker_file_t lf, Elf_Addr x) 1327 { 1328 elf_file_t ef; 1329 1330 KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class, 1331 ("elf_relocaddr: unexpected linker file %p", lf)); 1332 1333 ef = (elf_file_t)lf; 1334 if (x >= ef->pcpu_start && x < ef->pcpu_stop) 1335 return ((x - ef->pcpu_start) + ef->pcpu_base); 1336 #ifdef VIMAGE 1337 if (x >= ef->vnet_start && x < ef->vnet_stop) 1338 return ((x - ef->vnet_start) + ef->vnet_base); 1339 #endif 1340 return (x); 1341 } 1342 1343 static void 1344 link_elf_unload_file(linker_file_t file) 1345 { 1346 elf_file_t ef = (elf_file_t) file; 1347 1348 if (ef->pcpu_base != 0) { 1349 dpcpu_free((void *)ef->pcpu_base, 1350 ef->pcpu_stop - ef->pcpu_start); 1351 elf_set_delete(&set_pcpu_list, ef->pcpu_start); 1352 } 1353 #ifdef VIMAGE 1354 if (ef->vnet_base != 0) { 1355 vnet_data_free((void *)ef->vnet_base, 1356 ef->vnet_stop - ef->vnet_start); 1357 elf_set_delete(&set_vnet_list, ef->vnet_start); 1358 } 1359 #endif 1360 #ifdef GDB 1361 if (ef->gdb.l_ld != NULL) { 1362 GDB_STATE(RT_DELETE); 1363 free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); 1364 link_elf_delete_gdb(&ef->gdb); 1365 GDB_STATE(RT_CONSISTENT); 1366 } 1367 #endif 1368 1369 /* Notify MD code that a module is being unloaded. */ 1370 elf_cpu_unload_file(file); 1371 1372 if (ef->preloaded) { 1373 link_elf_unload_preload(file); 1374 return; 1375 } 1376 1377 #ifdef SPARSE_MAPPING 1378 if (ef->object != NULL) { 1379 vm_map_remove(kernel_map, (vm_offset_t) ef->address, 1380 (vm_offset_t) ef->address 1381 + (ef->object->size << PAGE_SHIFT)); 1382 } 1383 #else 1384 free(ef->address, M_LINKER); 1385 #endif 1386 free(ef->symbase, M_LINKER); 1387 free(ef->strbase, M_LINKER); 1388 free(ef->ctftab, M_LINKER); 1389 free(ef->ctfoff, M_LINKER); 1390 free(ef->typoff, M_LINKER); 1391 } 1392 1393 static void 1394 link_elf_unload_preload(linker_file_t file) 1395 { 1396 1397 if (file->pathname != NULL) 1398 preload_delete_name(file->pathname); 1399 } 1400 1401 static const char * 1402 symbol_name(elf_file_t ef, Elf_Size r_info) 1403 { 1404 const Elf_Sym *ref; 1405 1406 if (ELF_R_SYM(r_info)) { 1407 ref = ef->symtab + ELF_R_SYM(r_info); 1408 return (ef->strtab + ref->st_name); 1409 } 1410 return (NULL); 1411 } 1412 1413 static int 1414 symbol_type(elf_file_t ef, Elf_Size r_info) 1415 { 1416 const Elf_Sym *ref; 1417 1418 if (ELF_R_SYM(r_info)) { 1419 ref = ef->symtab + ELF_R_SYM(r_info); 1420 return (ELF_ST_TYPE(ref->st_info)); 1421 } 1422 return (STT_NOTYPE); 1423 } 1424 1425 static int 1426 relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc, 1427 bool ifuncs) 1428 { 1429 const Elf_Rel *rel; 1430 const Elf_Rela *rela; 1431 const char *symname; 1432 1433 #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \ 1434 for ((iter) = (tbl); (iter) != NULL && \ 1435 (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \ 1436 if ((symbol_type(ef, (iter)->r_info) == \ 1437 STT_GNU_IFUNC || \ 1438 elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \ 1439 continue; \ 1440 if (reloc(&ef->lf, (Elf_Addr)ef->address, \ 1441 (iter), (type), lookup)) { \ 1442 symname = symbol_name(ef, (iter)->r_info); \ 1443 printf("link_elf: symbol %s undefined\n", \ 1444 symname); \ 1445 return (ENOENT); \ 1446 } \ 1447 } \ 1448 } while (0) 1449 1450 APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL); 1451 APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA); 1452 APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL); 1453 APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA); 1454 1455 #undef APPLY_RELOCS 1456 1457 return (0); 1458 } 1459 1460 static int 1461 relocate_file(elf_file_t ef) 1462 { 1463 int error; 1464 1465 error = relocate_file1(ef, elf_lookup, elf_reloc, false); 1466 if (error == 0) 1467 error = relocate_file1(ef, elf_lookup, elf_reloc, true); 1468 return (error); 1469 } 1470 1471 /* 1472 * Hash function for symbol table lookup. Don't even think about changing 1473 * this. It is specified by the System V ABI. 1474 */ 1475 static unsigned long 1476 elf_hash(const char *name) 1477 { 1478 const unsigned char *p = (const unsigned char *) name; 1479 unsigned long h = 0; 1480 unsigned long g; 1481 1482 while (*p != '\0') { 1483 h = (h << 4) + *p++; 1484 if ((g = h & 0xf0000000) != 0) 1485 h ^= g >> 24; 1486 h &= ~g; 1487 } 1488 return (h); 1489 } 1490 1491 static int 1492 link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) 1493 { 1494 elf_file_t ef = (elf_file_t) lf; 1495 unsigned long symnum; 1496 const Elf_Sym* symp; 1497 const char *strp; 1498 unsigned long hash; 1499 int i; 1500 1501 /* If we don't have a hash, bail. */ 1502 if (ef->buckets == NULL || ef->nbuckets == 0) { 1503 printf("link_elf_lookup_symbol: missing symbol hash table\n"); 1504 return (ENOENT); 1505 } 1506 1507 /* First, search hashed global symbols */ 1508 hash = elf_hash(name); 1509 symnum = ef->buckets[hash % ef->nbuckets]; 1510 1511 while (symnum != STN_UNDEF) { 1512 if (symnum >= ef->nchains) { 1513 printf("%s: corrupt symbol table\n", __func__); 1514 return (ENOENT); 1515 } 1516 1517 symp = ef->symtab + symnum; 1518 if (symp->st_name == 0) { 1519 printf("%s: corrupt symbol table\n", __func__); 1520 return (ENOENT); 1521 } 1522 1523 strp = ef->strtab + symp->st_name; 1524 1525 if (strcmp(name, strp) == 0) { 1526 if (symp->st_shndx != SHN_UNDEF || 1527 (symp->st_value != 0 && 1528 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1529 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1530 *sym = (c_linker_sym_t) symp; 1531 return (0); 1532 } 1533 return (ENOENT); 1534 } 1535 1536 symnum = ef->chains[symnum]; 1537 } 1538 1539 /* If we have not found it, look at the full table (if loaded) */ 1540 if (ef->symtab == ef->ddbsymtab) 1541 return (ENOENT); 1542 1543 /* Exhaustive search */ 1544 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1545 strp = ef->ddbstrtab + symp->st_name; 1546 if (strcmp(name, strp) == 0) { 1547 if (symp->st_shndx != SHN_UNDEF || 1548 (symp->st_value != 0 && 1549 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1550 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { 1551 *sym = (c_linker_sym_t) symp; 1552 return (0); 1553 } 1554 return (ENOENT); 1555 } 1556 } 1557 1558 return (ENOENT); 1559 } 1560 1561 static int 1562 link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, 1563 linker_symval_t *symval) 1564 { 1565 elf_file_t ef; 1566 const Elf_Sym *es; 1567 caddr_t val; 1568 1569 ef = (elf_file_t)lf; 1570 es = (const Elf_Sym *)sym; 1571 if (es >= ef->symtab && es < (ef->symtab + ef->nchains)) { 1572 symval->name = ef->strtab + es->st_name; 1573 val = (caddr_t)ef->address + es->st_value; 1574 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1575 val = ((caddr_t (*)(void))val)(); 1576 symval->value = val; 1577 symval->size = es->st_size; 1578 return (0); 1579 } 1580 if (ef->symtab == ef->ddbsymtab) 1581 return (ENOENT); 1582 if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { 1583 symval->name = ef->ddbstrtab + es->st_name; 1584 val = (caddr_t)ef->address + es->st_value; 1585 if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) 1586 val = ((caddr_t (*)(void))val)(); 1587 symval->value = val; 1588 symval->size = es->st_size; 1589 return (0); 1590 } 1591 return (ENOENT); 1592 } 1593 1594 static int 1595 link_elf_search_symbol(linker_file_t lf, caddr_t value, 1596 c_linker_sym_t *sym, long *diffp) 1597 { 1598 elf_file_t ef = (elf_file_t) lf; 1599 u_long off = (uintptr_t) (void *) value; 1600 u_long diff = off; 1601 u_long st_value; 1602 const Elf_Sym* es; 1603 const Elf_Sym* best = NULL; 1604 int i; 1605 1606 for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { 1607 if (es->st_name == 0) 1608 continue; 1609 st_value = es->st_value + (uintptr_t) (void *) ef->address; 1610 if (off >= st_value) { 1611 if (off - st_value < diff) { 1612 diff = off - st_value; 1613 best = es; 1614 if (diff == 0) 1615 break; 1616 } else if (off - st_value == diff) { 1617 best = es; 1618 } 1619 } 1620 } 1621 if (best == NULL) 1622 *diffp = off; 1623 else 1624 *diffp = diff; 1625 *sym = (c_linker_sym_t) best; 1626 1627 return (0); 1628 } 1629 1630 /* 1631 * Look up a linker set on an ELF system. 1632 */ 1633 static int 1634 link_elf_lookup_set(linker_file_t lf, const char *name, 1635 void ***startp, void ***stopp, int *countp) 1636 { 1637 c_linker_sym_t sym; 1638 linker_symval_t symval; 1639 char *setsym; 1640 void **start, **stop; 1641 int len, error = 0, count; 1642 1643 len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ 1644 setsym = malloc(len, M_LINKER, M_WAITOK); 1645 1646 /* get address of first entry */ 1647 snprintf(setsym, len, "%s%s", "__start_set_", name); 1648 error = link_elf_lookup_symbol(lf, setsym, &sym); 1649 if (error != 0) 1650 goto out; 1651 link_elf_symbol_values(lf, sym, &symval); 1652 if (symval.value == 0) { 1653 error = ESRCH; 1654 goto out; 1655 } 1656 start = (void **)symval.value; 1657 1658 /* get address of last entry */ 1659 snprintf(setsym, len, "%s%s", "__stop_set_", name); 1660 error = link_elf_lookup_symbol(lf, setsym, &sym); 1661 if (error != 0) 1662 goto out; 1663 link_elf_symbol_values(lf, sym, &symval); 1664 if (symval.value == 0) { 1665 error = ESRCH; 1666 goto out; 1667 } 1668 stop = (void **)symval.value; 1669 1670 /* and the number of entries */ 1671 count = stop - start; 1672 1673 /* and copy out */ 1674 if (startp != NULL) 1675 *startp = start; 1676 if (stopp != NULL) 1677 *stopp = stop; 1678 if (countp != NULL) 1679 *countp = count; 1680 1681 out: 1682 free(setsym, M_LINKER); 1683 return (error); 1684 } 1685 1686 static int 1687 link_elf_each_function_name(linker_file_t file, 1688 int (*callback)(const char *, void *), void *opaque) 1689 { 1690 elf_file_t ef = (elf_file_t)file; 1691 const Elf_Sym *symp; 1692 int i, error; 1693 1694 /* Exhaustive search */ 1695 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1696 if (symp->st_value != 0 && 1697 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1698 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1699 error = callback(ef->ddbstrtab + symp->st_name, opaque); 1700 if (error != 0) 1701 return (error); 1702 } 1703 } 1704 return (0); 1705 } 1706 1707 static int 1708 link_elf_each_function_nameval(linker_file_t file, 1709 linker_function_nameval_callback_t callback, void *opaque) 1710 { 1711 linker_symval_t symval; 1712 elf_file_t ef = (elf_file_t)file; 1713 const Elf_Sym* symp; 1714 int i, error; 1715 1716 /* Exhaustive search */ 1717 for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { 1718 if (symp->st_value != 0 && 1719 (ELF_ST_TYPE(symp->st_info) == STT_FUNC || 1720 ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { 1721 error = link_elf_symbol_values(file, 1722 (c_linker_sym_t) symp, &symval); 1723 if (error != 0) 1724 return (error); 1725 error = callback(file, i, &symval, opaque); 1726 if (error != 0) 1727 return (error); 1728 } 1729 } 1730 return (0); 1731 } 1732 1733 const Elf_Sym * 1734 elf_get_sym(linker_file_t lf, Elf_Size symidx) 1735 { 1736 elf_file_t ef = (elf_file_t)lf; 1737 1738 if (symidx >= ef->nchains) 1739 return (NULL); 1740 return (ef->symtab + symidx); 1741 } 1742 1743 const char * 1744 elf_get_symname(linker_file_t lf, Elf_Size symidx) 1745 { 1746 elf_file_t ef = (elf_file_t)lf; 1747 const Elf_Sym *sym; 1748 1749 if (symidx >= ef->nchains) 1750 return (NULL); 1751 sym = ef->symtab + symidx; 1752 return (ef->strtab + sym->st_name); 1753 } 1754 1755 /* 1756 * Symbol lookup function that can be used when the symbol index is known (ie 1757 * in relocations). It uses the symbol index instead of doing a fully fledged 1758 * hash table based lookup when such is valid. For example for local symbols. 1759 * This is not only more efficient, it's also more correct. It's not always 1760 * the case that the symbol can be found through the hash table. 1761 */ 1762 static int 1763 elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) 1764 { 1765 elf_file_t ef = (elf_file_t)lf; 1766 const Elf_Sym *sym; 1767 const char *symbol; 1768 Elf_Addr addr, start, base; 1769 1770 /* Don't even try to lookup the symbol if the index is bogus. */ 1771 if (symidx >= ef->nchains) { 1772 *res = 0; 1773 return (EINVAL); 1774 } 1775 1776 sym = ef->symtab + symidx; 1777 1778 /* 1779 * Don't do a full lookup when the symbol is local. It may even 1780 * fail because it may not be found through the hash table. 1781 */ 1782 if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { 1783 /* Force lookup failure when we have an insanity. */ 1784 if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) { 1785 *res = 0; 1786 return (EINVAL); 1787 } 1788 *res = ((Elf_Addr)ef->address + sym->st_value); 1789 return (0); 1790 } 1791 1792 /* 1793 * XXX we can avoid doing a hash table based lookup for global 1794 * symbols as well. This however is not always valid, so we'll 1795 * just do it the hard way for now. Performance tweaks can 1796 * always be added. 1797 */ 1798 1799 symbol = ef->strtab + sym->st_name; 1800 1801 /* Force a lookup failure if the symbol name is bogus. */ 1802 if (*symbol == 0) { 1803 *res = 0; 1804 return (EINVAL); 1805 } 1806 1807 addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); 1808 if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) { 1809 *res = 0; 1810 return (EINVAL); 1811 } 1812 1813 if (elf_set_find(&set_pcpu_list, addr, &start, &base)) 1814 addr = addr - start + base; 1815 #ifdef VIMAGE 1816 else if (elf_set_find(&set_vnet_list, addr, &start, &base)) 1817 addr = addr - start + base; 1818 #endif 1819 *res = addr; 1820 return (0); 1821 } 1822 1823 static void 1824 link_elf_reloc_local(linker_file_t lf) 1825 { 1826 const Elf_Rel *rellim; 1827 const Elf_Rel *rel; 1828 const Elf_Rela *relalim; 1829 const Elf_Rela *rela; 1830 elf_file_t ef = (elf_file_t)lf; 1831 1832 /* Perform relocations without addend if there are any: */ 1833 if ((rel = ef->rel) != NULL) { 1834 rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); 1835 while (rel < rellim) { 1836 elf_reloc_local(lf, (Elf_Addr)ef->address, rel, 1837 ELF_RELOC_REL, elf_lookup); 1838 rel++; 1839 } 1840 } 1841 1842 /* Perform relocations with addend if there are any: */ 1843 if ((rela = ef->rela) != NULL) { 1844 relalim = (const Elf_Rela *) 1845 ((const char *)ef->rela + ef->relasize); 1846 while (rela < relalim) { 1847 elf_reloc_local(lf, (Elf_Addr)ef->address, rela, 1848 ELF_RELOC_RELA, elf_lookup); 1849 rela++; 1850 } 1851 } 1852 } 1853 1854 static long 1855 link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) 1856 { 1857 elf_file_t ef = (elf_file_t)lf; 1858 1859 *symtab = ef->ddbsymtab; 1860 1861 if (*symtab == NULL) 1862 return (0); 1863 1864 return (ef->ddbsymcnt); 1865 } 1866 1867 static long 1868 link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) 1869 { 1870 elf_file_t ef = (elf_file_t)lf; 1871 1872 *strtab = ef->ddbstrtab; 1873 1874 if (*strtab == NULL) 1875 return (0); 1876 1877 return (ef->ddbstrcnt); 1878 } 1879 1880 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) || defined(__powerpc__) 1881 /* 1882 * Use this lookup routine when performing relocations early during boot. 1883 * The generic lookup routine depends on kobj, which is not initialized 1884 * at that point. 1885 */ 1886 static int 1887 elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused, 1888 Elf_Addr *res) 1889 { 1890 elf_file_t ef; 1891 const Elf_Sym *symp; 1892 caddr_t val; 1893 1894 ef = (elf_file_t)lf; 1895 symp = ef->symtab + symidx; 1896 if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) { 1897 val = (caddr_t)ef->address + symp->st_value; 1898 *res = ((Elf_Addr (*)(void))val)(); 1899 return (0); 1900 } 1901 return (ENOENT); 1902 } 1903 1904 void 1905 link_elf_ireloc(caddr_t kmdp) 1906 { 1907 struct elf_file eff; 1908 elf_file_t ef; 1909 1910 ef = &eff; 1911 1912 bzero_early(ef, sizeof(*ef)); 1913 1914 ef->modptr = kmdp; 1915 ef->dynamic = (Elf_Dyn *)&_DYNAMIC; 1916 1917 #ifdef RELOCATABLE_KERNEL 1918 ef->address = (caddr_t) (__startkernel - KERNBASE); 1919 #else 1920 ef->address = 0; 1921 #endif 1922 parse_dynamic(ef); 1923 1924 link_elf_preload_parse_symbols(ef); 1925 relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true); 1926 } 1927 1928 #if defined(__aarch64__) || defined(__amd64__) 1929 void 1930 link_elf_late_ireloc(void) 1931 { 1932 elf_file_t ef; 1933 1934 KASSERT(linker_kernel_file != NULL, 1935 ("link_elf_late_ireloc: No kernel linker file found")); 1936 ef = (elf_file_t)linker_kernel_file; 1937 1938 relocate_file1(ef, elf_lookup_ifunc, elf_reloc_late, true); 1939 } 1940 #endif 1941 #endif 1942