138816Sdfr/*- 248205Sjdp * Copyright 1996, 1997, 1998, 1999 John D. Polstra. 338816Sdfr * All rights reserved. 438816Sdfr * 538816Sdfr * Redistribution and use in source and binary forms, with or without 638816Sdfr * modification, are permitted provided that the following conditions 738816Sdfr * are met: 838816Sdfr * 1. Redistributions of source code must retain the above copyright 938816Sdfr * notice, this list of conditions and the following disclaimer. 1038816Sdfr * 2. Redistributions in binary form must reproduce the above copyright 1138816Sdfr * notice, this list of conditions and the following disclaimer in the 1238816Sdfr * documentation and/or other materials provided with the distribution. 1338816Sdfr * 1438816Sdfr * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 1538816Sdfr * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 1638816Sdfr * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 1738816Sdfr * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 1838816Sdfr * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 1938816Sdfr * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 2038816Sdfr * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 2138816Sdfr * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 2238816Sdfr * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 2338816Sdfr * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 2438816Sdfr * 2550476Speter * $FreeBSD$ 2638816Sdfr */ 2738816Sdfr 2838816Sdfr/* 2938816Sdfr * Dynamic linker for ELF. 3038816Sdfr * 3138816Sdfr * John Polstra <jdp@polstra.com>. 3238816Sdfr */ 3338816Sdfr 3438816Sdfr#include <sys/param.h> 3538816Sdfr#include <sys/mman.h> 36133063Sdfr#include <machine/sysarch.h> 3738816Sdfr 3838816Sdfr#include <dlfcn.h> 3938816Sdfr#include <err.h> 4038816Sdfr#include <errno.h> 4138816Sdfr#include <fcntl.h> 4238816Sdfr#include <stdarg.h> 4338816Sdfr#include <stdio.h> 4438816Sdfr#include <stdlib.h> 4538816Sdfr#include <string.h> 4638816Sdfr#include <unistd.h> 4738816Sdfr 4838816Sdfr#include "debug.h" 4938816Sdfr#include "rtld.h" 5038816Sdfr 5138816Sdfr/* 52115280Speter * Process the special R_X86_64_COPY relocations in the main program. These 5338816Sdfr * copy data from a shared object into a region in the main program's BSS 5438816Sdfr * segment. 5538816Sdfr * 5638816Sdfr * Returns 0 on success, -1 on failure. 5738816Sdfr */ 5838816Sdfrint 5938816Sdfrdo_copy_relocations(Obj_Entry *dstobj) 6038816Sdfr{ 61115280Speter const Elf_Rela *relalim; 62115280Speter const Elf_Rela *rela; 6338816Sdfr 6438816Sdfr assert(dstobj->mainprog); /* COPY relocations are invalid elsewhere */ 6538816Sdfr 66115280Speter relalim = (const Elf_Rela *) ((caddr_t) dstobj->rela + dstobj->relasize); 67115280Speter for (rela = dstobj->rela; rela < relalim; rela++) { 68115280Speter if (ELF_R_TYPE(rela->r_info) == R_X86_64_COPY) { 6938816Sdfr void *dstaddr; 7038816Sdfr const Elf_Sym *dstsym; 7138816Sdfr const char *name; 7238816Sdfr size_t size; 7338816Sdfr const void *srcaddr; 7438816Sdfr const Elf_Sym *srcsym; 75216695Skib const Obj_Entry *srcobj, *defobj; 76216695Skib SymLook req; 77216695Skib int res; 7838816Sdfr 79115280Speter dstaddr = (void *) (dstobj->relocbase + rela->r_offset); 80115280Speter dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info); 8138816Sdfr name = dstobj->strtab + dstsym->st_name; 8238816Sdfr size = dstsym->st_size; 83216695Skib symlook_init(&req, name); 84216695Skib req.ventry = fetch_ventry(dstobj, ELF_R_SYM(rela->r_info)); 85233231Skib req.flags = SYMLOOK_EARLY; 8638816Sdfr 87216695Skib for (srcobj = dstobj->next; srcobj != NULL; srcobj = srcobj->next) { 88216695Skib res = symlook_obj(&req, srcobj); 89216695Skib if (res == 0) { 90216695Skib srcsym = req.sym_out; 91216695Skib defobj = req.defobj_out; 9238816Sdfr break; 93216695Skib } 94216695Skib } 9538816Sdfr 9638816Sdfr if (srcobj == NULL) { 9738816Sdfr _rtld_error("Undefined symbol \"%s\" referenced from COPY" 9838816Sdfr " relocation in %s", name, dstobj->path); 9938816Sdfr return -1; 10038816Sdfr } 10138816Sdfr 102216695Skib srcaddr = (const void *) (defobj->relocbase + srcsym->st_value); 10338816Sdfr memcpy(dstaddr, srcaddr, size); 10438816Sdfr } 10538816Sdfr } 10638816Sdfr 10738816Sdfr return 0; 10838816Sdfr} 10938816Sdfr 11045501Sjdp/* Initialize the special GOT entries. */ 11145501Sjdpvoid 11245501Sjdpinit_pltgot(Obj_Entry *obj) 11345501Sjdp{ 11445501Sjdp if (obj->pltgot != NULL) { 11545501Sjdp obj->pltgot[1] = (Elf_Addr) obj; 11645501Sjdp obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; 11745501Sjdp } 11845501Sjdp} 11945501Sjdp 12038816Sdfr/* Process the non-PLT relocations. */ 12138816Sdfrint 122233231Skibreloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags, 123233231Skib RtldLockState *lockstate) 12438816Sdfr{ 125115280Speter const Elf_Rela *relalim; 126115280Speter const Elf_Rela *rela; 12776296Sjdp SymCache *cache; 12898100Sdillon int r = -1; 12938816Sdfr 13098100Sdillon /* 13198100Sdillon * The dynamic loader may be called from a thread, we have 13298100Sdillon * limited amounts of stack available so we cannot use alloca(). 13398100Sdillon */ 134208256Srdivacky if (obj != obj_rtld) { 135234841Skib cache = calloc(obj->dynsymcount, sizeof(SymCache)); 136208256Srdivacky /* No need to check for NULL here */ 137208256Srdivacky } else 13898100Sdillon cache = NULL; 13976296Sjdp 140115280Speter relalim = (const Elf_Rela *) ((caddr_t) obj->rela + obj->relasize); 141115280Speter for (rela = obj->rela; rela < relalim; rela++) { 142115280Speter Elf_Addr *where = (Elf_Addr *) (obj->relocbase + rela->r_offset); 143123481Speter Elf32_Addr *where32 = (Elf32_Addr *)where; 14438816Sdfr 145115280Speter switch (ELF_R_TYPE(rela->r_info)) { 14638816Sdfr 147115280Speter case R_X86_64_NONE: 14838816Sdfr break; 14938816Sdfr 150115280Speter case R_X86_64_64: 15138816Sdfr { 15238816Sdfr const Elf_Sym *def; 15338816Sdfr const Obj_Entry *defobj; 15438816Sdfr 155115280Speter def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, 156233231Skib flags, cache, lockstate); 15738816Sdfr if (def == NULL) 15898100Sdillon goto done; 15938816Sdfr 160115280Speter *where = (Elf_Addr) (defobj->relocbase + def->st_value + rela->r_addend); 16138816Sdfr } 16238816Sdfr break; 16338816Sdfr 164115280Speter case R_X86_64_PC32: 16538816Sdfr /* 16638816Sdfr * I don't think the dynamic linker should ever see this 16738816Sdfr * type of relocation. But the binutils-2.6 tools sometimes 16838816Sdfr * generate it. 16938816Sdfr */ 17038816Sdfr { 17138816Sdfr const Elf_Sym *def; 17238816Sdfr const Obj_Entry *defobj; 17338816Sdfr 174115280Speter def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, 175233231Skib flags, cache, lockstate); 17638816Sdfr if (def == NULL) 17798100Sdillon goto done; 17838816Sdfr 179123481Speter *where32 = (Elf32_Addr) (unsigned long) (defobj->relocbase + 180123481Speter def->st_value + rela->r_addend - (Elf_Addr) where); 18138816Sdfr } 18238816Sdfr break; 183115280Speter /* missing: R_X86_64_GOT32 R_X86_64_PLT32 */ 18438816Sdfr 185115280Speter case R_X86_64_COPY: 18638816Sdfr /* 18738816Sdfr * These are deferred until all other relocations have 18838816Sdfr * been done. All we do here is make sure that the COPY 18938816Sdfr * relocation is not in a shared library. They are allowed 19038816Sdfr * only in executable files. 19138816Sdfr */ 19238816Sdfr if (!obj->mainprog) { 193115280Speter _rtld_error("%s: Unexpected R_X86_64_COPY relocation" 19438816Sdfr " in shared library", obj->path); 19598100Sdillon goto done; 19638816Sdfr } 19738816Sdfr break; 19838816Sdfr 199115280Speter case R_X86_64_GLOB_DAT: 20038816Sdfr { 20138816Sdfr const Elf_Sym *def; 20238816Sdfr const Obj_Entry *defobj; 20338816Sdfr 204115280Speter def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, 205233231Skib flags, cache, lockstate); 20638816Sdfr if (def == NULL) 20798100Sdillon goto done; 20838816Sdfr 20938816Sdfr *where = (Elf_Addr) (defobj->relocbase + def->st_value); 21038816Sdfr } 21138816Sdfr break; 21238816Sdfr 213133063Sdfr case R_X86_64_TPOFF64: 214133063Sdfr { 215133063Sdfr const Elf_Sym *def; 216133063Sdfr const Obj_Entry *defobj; 217133063Sdfr 218133063Sdfr def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, 219233231Skib flags, cache, lockstate); 220133063Sdfr if (def == NULL) 221133063Sdfr goto done; 222133063Sdfr 223133063Sdfr /* 224133063Sdfr * We lazily allocate offsets for static TLS as we 225133063Sdfr * see the first relocation that references the 226133063Sdfr * TLS block. This allows us to support (small 227133063Sdfr * amounts of) static TLS in dynamically loaded 228133063Sdfr * modules. If we run out of space, we generate an 229133063Sdfr * error. 230133063Sdfr */ 231133063Sdfr if (!defobj->tls_done) { 232133063Sdfr if (!allocate_tls_offset((Obj_Entry*) defobj)) { 233133063Sdfr _rtld_error("%s: No space available for static " 234133063Sdfr "Thread Local Storage", obj->path); 235133063Sdfr goto done; 236133063Sdfr } 237133063Sdfr } 238133063Sdfr 239133063Sdfr *where = (Elf_Addr) (def->st_value - defobj->tlsoffset + 240133063Sdfr rela->r_addend); 241133063Sdfr } 242133063Sdfr break; 243133063Sdfr 244133063Sdfr case R_X86_64_TPOFF32: 245133063Sdfr { 246133063Sdfr const Elf_Sym *def; 247133063Sdfr const Obj_Entry *defobj; 248133063Sdfr 249133063Sdfr def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, 250233231Skib flags, cache, lockstate); 251133063Sdfr if (def == NULL) 252133063Sdfr goto done; 253133063Sdfr 254133063Sdfr /* 255133063Sdfr * We lazily allocate offsets for static TLS as we 256133063Sdfr * see the first relocation that references the 257133063Sdfr * TLS block. This allows us to support (small 258133063Sdfr * amounts of) static TLS in dynamically loaded 259133063Sdfr * modules. If we run out of space, we generate an 260133063Sdfr * error. 261133063Sdfr */ 262133063Sdfr if (!defobj->tls_done) { 263133063Sdfr if (!allocate_tls_offset((Obj_Entry*) defobj)) { 264133063Sdfr _rtld_error("%s: No space available for static " 265133063Sdfr "Thread Local Storage", obj->path); 266133063Sdfr goto done; 267133063Sdfr } 268133063Sdfr } 269133063Sdfr 270133063Sdfr *where32 = (Elf32_Addr) (def->st_value - 271133063Sdfr defobj->tlsoffset + 272133063Sdfr rela->r_addend); 273133063Sdfr } 274133063Sdfr break; 275133063Sdfr 276133063Sdfr case R_X86_64_DTPMOD64: 277133063Sdfr { 278133063Sdfr const Elf_Sym *def; 279133063Sdfr const Obj_Entry *defobj; 280133063Sdfr 281133063Sdfr def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, 282233231Skib flags, cache, lockstate); 283133063Sdfr if (def == NULL) 284133063Sdfr goto done; 285133063Sdfr 286133063Sdfr *where += (Elf_Addr) defobj->tlsindex; 287133063Sdfr } 288133063Sdfr break; 289133063Sdfr 290133063Sdfr case R_X86_64_DTPOFF64: 291133063Sdfr { 292133063Sdfr const Elf_Sym *def; 293133063Sdfr const Obj_Entry *defobj; 294133063Sdfr 295133063Sdfr def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, 296233231Skib flags, cache, lockstate); 297133063Sdfr if (def == NULL) 298133063Sdfr goto done; 299133063Sdfr 300133063Sdfr *where += (Elf_Addr) (def->st_value + rela->r_addend); 301133063Sdfr } 302133063Sdfr break; 303133063Sdfr 304133063Sdfr case R_X86_64_DTPOFF32: 305133063Sdfr { 306133063Sdfr const Elf_Sym *def; 307133063Sdfr const Obj_Entry *defobj; 308133063Sdfr 309133063Sdfr def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, 310233231Skib flags, cache, lockstate); 311133063Sdfr if (def == NULL) 312133063Sdfr goto done; 313133063Sdfr 314133063Sdfr *where32 += (Elf32_Addr) (def->st_value + rela->r_addend); 315133063Sdfr } 316133063Sdfr break; 317133063Sdfr 318115280Speter case R_X86_64_RELATIVE: 319115280Speter *where = (Elf_Addr)(obj->relocbase + rela->r_addend); 32038816Sdfr break; 32138816Sdfr 322115280Speter /* missing: R_X86_64_GOTPCREL, R_X86_64_32, R_X86_64_32S, R_X86_64_16, R_X86_64_PC16, R_X86_64_8, R_X86_64_PC8 */ 323115280Speter 32438816Sdfr default: 325153503Smarcel _rtld_error("%s: Unsupported relocation type %u" 32638816Sdfr " in non-PLT relocations\n", obj->path, 327153503Smarcel (unsigned int)ELF_R_TYPE(rela->r_info)); 32898100Sdillon goto done; 32938816Sdfr } 33038816Sdfr } 33198103Sdillon r = 0; 33298103Sdillondone: 333208256Srdivacky if (cache != NULL) 334208256Srdivacky free(cache); 335233231Skib return (r); 33638816Sdfr} 33738816Sdfr 33838816Sdfr/* Process the PLT relocations. */ 33938816Sdfrint 34056780Sjdpreloc_plt(Obj_Entry *obj) 34138816Sdfr{ 342115280Speter const Elf_Rela *relalim; 343115280Speter const Elf_Rela *rela; 34438816Sdfr 345115280Speter relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize); 346115280Speter for (rela = obj->pltrela; rela < relalim; rela++) { 34748205Sjdp Elf_Addr *where; 34838816Sdfr 349228435Skib switch(ELF_R_TYPE(rela->r_info)) { 350228435Skib case R_X86_64_JMP_SLOT: 351228435Skib /* Relocate the GOT slot pointing into the PLT. */ 352228435Skib where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 353228435Skib *where += (Elf_Addr)obj->relocbase; 354228435Skib break; 35538816Sdfr 356228435Skib case R_X86_64_IRELATIVE: 357228435Skib obj->irelative = true; 358228435Skib break; 359228435Skib 360228435Skib default: 361228435Skib _rtld_error("Unknown relocation type %x in PLT", 362228435Skib (unsigned int)ELF_R_TYPE(rela->r_info)); 363228435Skib return (-1); 364228435Skib } 36556780Sjdp } 36656780Sjdp return 0; 36756780Sjdp} 36838816Sdfr 36956780Sjdp/* Relocate the jump slots in an object. */ 37056780Sjdpint 371233231Skibreloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate) 37256780Sjdp{ 373115280Speter const Elf_Rela *relalim; 374115280Speter const Elf_Rela *rela; 37548205Sjdp 37656780Sjdp if (obj->jmpslots_done) 37756780Sjdp return 0; 378115280Speter relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize); 379115280Speter for (rela = obj->pltrela; rela < relalim; rela++) { 38085004Sdfr Elf_Addr *where, target; 38156780Sjdp const Elf_Sym *def; 38256780Sjdp const Obj_Entry *defobj; 38356780Sjdp 384228435Skib switch (ELF_R_TYPE(rela->r_info)) { 385228435Skib case R_X86_64_JMP_SLOT: 386228435Skib where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 387233231Skib def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, 388233231Skib SYMLOOK_IN_PLT | flags, NULL, lockstate); 389228435Skib if (def == NULL) 390228435Skib return (-1); 391228435Skib if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) { 392228435Skib obj->gnu_ifunc = true; 393228435Skib continue; 394228435Skib } 395228435Skib target = (Elf_Addr)(defobj->relocbase + def->st_value + rela->r_addend); 396228435Skib reloc_jmpslot(where, target, defobj, obj, (const Elf_Rel *)rela); 397228435Skib break; 398228435Skib 399228435Skib case R_X86_64_IRELATIVE: 400228435Skib break; 401228435Skib 402228435Skib default: 403228435Skib _rtld_error("Unknown relocation type %x in PLT", 404228435Skib (unsigned int)ELF_R_TYPE(rela->r_info)); 405228435Skib return (-1); 406228435Skib } 40748205Sjdp } 40856780Sjdp obj->jmpslots_done = true; 40938816Sdfr return 0; 41038816Sdfr} 411133063Sdfr 412228435Skibint 413228435Skibreloc_iresolve(Obj_Entry *obj, RtldLockState *lockstate) 414228435Skib{ 415228435Skib const Elf_Rela *relalim; 416228435Skib const Elf_Rela *rela; 417228435Skib 418228503Skib if (!obj->irelative) 419228503Skib return (0); 420228435Skib relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize); 421228435Skib for (rela = obj->pltrela; rela < relalim; rela++) { 422228435Skib Elf_Addr *where, target, *ptr; 423228435Skib 424228435Skib switch (ELF_R_TYPE(rela->r_info)) { 425228435Skib case R_X86_64_JMP_SLOT: 426228435Skib break; 427228435Skib 428228435Skib case R_X86_64_IRELATIVE: 429228435Skib ptr = (Elf_Addr *)(obj->relocbase + rela->r_addend); 430228435Skib where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 431228503Skib lock_release(rtld_bind_lock, lockstate); 432228435Skib target = ((Elf_Addr (*)(void))ptr)(); 433228503Skib wlock_acquire(rtld_bind_lock, lockstate); 434228435Skib *where = target; 435228435Skib break; 436228435Skib } 437228435Skib } 438228503Skib obj->irelative = false; 439228435Skib return (0); 440228435Skib} 441228435Skib 442228435Skibint 443233231Skibreloc_gnu_ifunc(Obj_Entry *obj, int flags, RtldLockState *lockstate) 444228435Skib{ 445228435Skib const Elf_Rela *relalim; 446228435Skib const Elf_Rela *rela; 447228435Skib 448228435Skib if (!obj->gnu_ifunc) 449228435Skib return (0); 450228435Skib relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize); 451228435Skib for (rela = obj->pltrela; rela < relalim; rela++) { 452228435Skib Elf_Addr *where, target; 453228435Skib const Elf_Sym *def; 454228435Skib const Obj_Entry *defobj; 455228435Skib 456228435Skib switch (ELF_R_TYPE(rela->r_info)) { 457228435Skib case R_X86_64_JMP_SLOT: 458228435Skib where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 459233231Skib def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, 460233231Skib SYMLOOK_IN_PLT | flags, NULL, lockstate); 461228435Skib if (def == NULL) 462228435Skib return (-1); 463228435Skib if (ELF_ST_TYPE(def->st_info) != STT_GNU_IFUNC) 464228435Skib continue; 465228503Skib lock_release(rtld_bind_lock, lockstate); 466228435Skib target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 467228503Skib wlock_acquire(rtld_bind_lock, lockstate); 468228435Skib reloc_jmpslot(where, target, defobj, obj, (const Elf_Rel *)rela); 469228435Skib break; 470228435Skib } 471228435Skib } 472228435Skib obj->gnu_ifunc = false; 473228503Skib return (0); 474228435Skib} 475228435Skib 476133063Sdfrvoid 477133063Sdfrallocate_initial_tls(Obj_Entry *objs) 478133063Sdfr{ 479133063Sdfr /* 480133063Sdfr * Fix the size of the static TLS block by using the maximum 481133063Sdfr * offset allocated so far and adding a bit for dynamic modules to 482133063Sdfr * use. 483133063Sdfr */ 484133063Sdfr tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA; 485133063Sdfr amd64_set_fsbase(allocate_tls(objs, 0, 486157198Sdavidxu 3*sizeof(Elf_Addr), sizeof(Elf_Addr))); 487133063Sdfr} 488133063Sdfr 489133063Sdfrvoid *__tls_get_addr(tls_index *ti) 490133063Sdfr{ 491133063Sdfr Elf_Addr** segbase; 492133063Sdfr 493133063Sdfr __asm __volatile("movq %%fs:0, %0" : "=r" (segbase)); 494133063Sdfr 495133063Sdfr return tls_get_addr_common(&segbase[1], ti->ti_module, ti->ti_offset); 496133063Sdfr} 497