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; 128271469Skib const Elf_Sym *def; 129271469Skib const Obj_Entry *defobj; 130271469Skib Elf_Addr *where, symval; 131271469Skib Elf32_Addr *where32; 132271469Skib int r; 13338816Sdfr 134271469Skib r = -1; 13598100Sdillon /* 13698100Sdillon * The dynamic loader may be called from a thread, we have 13798100Sdillon * limited amounts of stack available so we cannot use alloca(). 13898100Sdillon */ 139208256Srdivacky if (obj != obj_rtld) { 140271469Skib cache = calloc(obj->dynsymcount, sizeof(SymCache)); 141271469Skib /* No need to check for NULL here */ 142208256Srdivacky } else 143271469Skib cache = NULL; 14476296Sjdp 145271469Skib relalim = (const Elf_Rela *)((caddr_t)obj->rela + obj->relasize); 146115280Speter for (rela = obj->rela; rela < relalim; rela++) { 14738816Sdfr /* 148271469Skib * First, resolve symbol for relocations which 149271469Skib * reference symbols. 15038816Sdfr */ 151271469Skib switch (ELF_R_TYPE(rela->r_info)) { 152271469Skib case R_X86_64_64: 153271469Skib case R_X86_64_PC32: 154271469Skib case R_X86_64_GLOB_DAT: 155271469Skib case R_X86_64_TPOFF64: 156271469Skib case R_X86_64_TPOFF32: 157271469Skib case R_X86_64_DTPMOD64: 158271469Skib case R_X86_64_DTPOFF64: 159271469Skib case R_X86_64_DTPOFF32: 160271469Skib def = find_symdef(ELF_R_SYM(rela->r_info), obj, 161271469Skib &defobj, flags, cache, lockstate); 162271469Skib if (def == NULL) 163271469Skib goto done; 164271469Skib /* 165271469Skib * If symbol is IFUNC, only perform relocation 166271469Skib * when caller allowed it by passing 167271469Skib * SYMLOOK_IFUNC flag. Skip the relocations 168271469Skib * otherwise. 169271469Skib * 170271469Skib * Also error out in case IFUNC relocations 171271469Skib * are specified for TLS, which cannot be 172271469Skib * usefully interpreted. 173271469Skib */ 174271469Skib if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) { 175271469Skib switch (ELF_R_TYPE(rela->r_info)) { 176271469Skib case R_X86_64_64: 177271469Skib case R_X86_64_PC32: 178271469Skib case R_X86_64_GLOB_DAT: 179271469Skib if ((flags & SYMLOOK_IFUNC) == 0) { 180271469Skib obj->non_plt_gnu_ifunc = true; 181271469Skib continue; 182271469Skib } 183271469Skib symval = (Elf_Addr)rtld_resolve_ifunc( 184271469Skib defobj, def); 185271469Skib break; 186271469Skib case R_X86_64_TPOFF64: 187271469Skib case R_X86_64_TPOFF32: 188271469Skib case R_X86_64_DTPMOD64: 189271469Skib case R_X86_64_DTPOFF64: 190271469Skib case R_X86_64_DTPOFF32: 191271469Skib _rtld_error("%s: IFUNC for TLS reloc", 192271469Skib obj->path); 193271469Skib goto done; 194271469Skib } 195271469Skib } else { 196271469Skib if ((flags & SYMLOOK_IFUNC) != 0) 197271469Skib continue; 198271469Skib symval = (Elf_Addr)defobj->relocbase + 199271469Skib def->st_value; 200271469Skib } 201271469Skib break; 202271469Skib default: 203271469Skib if ((flags & SYMLOOK_IFUNC) != 0) 204271469Skib continue; 205271469Skib break; 20638816Sdfr } 207271469Skib where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 208271469Skib where32 = (Elf32_Addr *)where; 20938816Sdfr 210271469Skib switch (ELF_R_TYPE(rela->r_info)) { 211271469Skib case R_X86_64_NONE: 212271469Skib break; 213271469Skib case R_X86_64_64: 214271469Skib *where = symval + rela->r_addend; 215271469Skib break; 216271469Skib case R_X86_64_PC32: 217271469Skib /* 218271469Skib * I don't think the dynamic linker should 219271469Skib * ever see this type of relocation. But the 220271469Skib * binutils-2.6 tools sometimes generate it. 221271469Skib */ 222271469Skib *where32 = (Elf32_Addr)(unsigned long)(symval + 223271469Skib rela->r_addend - (Elf_Addr)where); 224271469Skib break; 225271469Skib /* missing: R_X86_64_GOT32 R_X86_64_PLT32 */ 226271469Skib case R_X86_64_COPY: 227271469Skib /* 228271469Skib * These are deferred until all other relocations have 229271469Skib * been done. All we do here is make sure that the COPY 230271469Skib * relocation is not in a shared library. They are allowed 231271469Skib * only in executable files. 232271469Skib */ 233271469Skib if (!obj->mainprog) { 234271469Skib _rtld_error("%s: Unexpected R_X86_64_COPY " 235271469Skib "relocation in shared library", obj->path); 236271469Skib goto done; 237271469Skib } 238271469Skib break; 239271469Skib case R_X86_64_GLOB_DAT: 240271469Skib *where = symval; 241271469Skib break; 242271469Skib case R_X86_64_TPOFF64: 243271469Skib /* 244271469Skib * We lazily allocate offsets for static TLS 245271469Skib * as we see the first relocation that 246271469Skib * references the TLS block. This allows us to 247271469Skib * support (small amounts of) static TLS in 248271469Skib * dynamically loaded modules. If we run out 249271469Skib * of space, we generate an error. 250271469Skib */ 251271469Skib if (!defobj->tls_done) { 252271469Skib if (!allocate_tls_offset((Obj_Entry*) defobj)) { 253271469Skib _rtld_error("%s: No space available " 254271469Skib "for static Thread Local Storage", 255271469Skib obj->path); 256271469Skib goto done; 257271469Skib } 258271469Skib } 259271469Skib *where = (Elf_Addr)(def->st_value - defobj->tlsoffset + 260271469Skib rela->r_addend); 261271469Skib break; 262271469Skib case R_X86_64_TPOFF32: 263271469Skib /* 264271469Skib * We lazily allocate offsets for static TLS 265271469Skib * as we see the first relocation that 266271469Skib * references the TLS block. This allows us to 267271469Skib * support (small amounts of) static TLS in 268271469Skib * dynamically loaded modules. If we run out 269271469Skib * of space, we generate an error. 270271469Skib */ 271271469Skib if (!defobj->tls_done) { 272271469Skib if (!allocate_tls_offset((Obj_Entry*) defobj)) { 273271469Skib _rtld_error("%s: No space available " 274271469Skib "for static Thread Local Storage", 275271469Skib obj->path); 276271469Skib goto done; 277271469Skib } 278271469Skib } 279271469Skib *where32 = (Elf32_Addr)(def->st_value - 280271469Skib defobj->tlsoffset + rela->r_addend); 281271469Skib break; 282271469Skib case R_X86_64_DTPMOD64: 283271469Skib *where += (Elf_Addr)defobj->tlsindex; 284271469Skib break; 285271469Skib case R_X86_64_DTPOFF64: 286271469Skib *where += (Elf_Addr)(def->st_value + rela->r_addend); 287271469Skib break; 288271469Skib case R_X86_64_DTPOFF32: 289271469Skib *where32 += (Elf32_Addr)(def->st_value + 290271469Skib rela->r_addend); 291271469Skib break; 292271469Skib case R_X86_64_RELATIVE: 293271469Skib *where = (Elf_Addr)(obj->relocbase + rela->r_addend); 294271469Skib break; 29538816Sdfr /* 296271469Skib * missing: 297271469Skib * R_X86_64_GOTPCREL, R_X86_64_32, R_X86_64_32S, R_X86_64_16, 298271469Skib * R_X86_64_PC16, R_X86_64_8, R_X86_64_PC8 29938816Sdfr */ 300271469Skib default: 301271469Skib _rtld_error("%s: Unsupported relocation type %u" 302271469Skib " in non-PLT relocations\n", obj->path, 303271469Skib (unsigned int)ELF_R_TYPE(rela->r_info)); 30498100Sdillon goto done; 30538816Sdfr } 30638816Sdfr } 30798103Sdillon r = 0; 30898103Sdillondone: 309271469Skib free(cache); 310233231Skib return (r); 31138816Sdfr} 31238816Sdfr 31338816Sdfr/* Process the PLT relocations. */ 31438816Sdfrint 31556780Sjdpreloc_plt(Obj_Entry *obj) 31638816Sdfr{ 317115280Speter const Elf_Rela *relalim; 318115280Speter const Elf_Rela *rela; 31938816Sdfr 320115280Speter relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize); 321115280Speter for (rela = obj->pltrela; rela < relalim; rela++) { 32248205Sjdp Elf_Addr *where; 32338816Sdfr 324228435Skib switch(ELF_R_TYPE(rela->r_info)) { 325228435Skib case R_X86_64_JMP_SLOT: 326228435Skib /* Relocate the GOT slot pointing into the PLT. */ 327228435Skib where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 328228435Skib *where += (Elf_Addr)obj->relocbase; 329228435Skib break; 33038816Sdfr 331228435Skib case R_X86_64_IRELATIVE: 332228435Skib obj->irelative = true; 333228435Skib break; 334228435Skib 335228435Skib default: 336228435Skib _rtld_error("Unknown relocation type %x in PLT", 337228435Skib (unsigned int)ELF_R_TYPE(rela->r_info)); 338228435Skib return (-1); 339228435Skib } 34056780Sjdp } 34156780Sjdp return 0; 34256780Sjdp} 34338816Sdfr 34456780Sjdp/* Relocate the jump slots in an object. */ 34556780Sjdpint 346233231Skibreloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate) 34756780Sjdp{ 348115280Speter const Elf_Rela *relalim; 349115280Speter const Elf_Rela *rela; 35048205Sjdp 35156780Sjdp if (obj->jmpslots_done) 35256780Sjdp return 0; 353115280Speter relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize); 354115280Speter for (rela = obj->pltrela; rela < relalim; rela++) { 35585004Sdfr Elf_Addr *where, target; 35656780Sjdp const Elf_Sym *def; 35756780Sjdp const Obj_Entry *defobj; 35856780Sjdp 359228435Skib switch (ELF_R_TYPE(rela->r_info)) { 360228435Skib case R_X86_64_JMP_SLOT: 361228435Skib where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 362233231Skib def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, 363233231Skib SYMLOOK_IN_PLT | flags, NULL, lockstate); 364228435Skib if (def == NULL) 365228435Skib return (-1); 366228435Skib if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) { 367228435Skib obj->gnu_ifunc = true; 368228435Skib continue; 369228435Skib } 370228435Skib target = (Elf_Addr)(defobj->relocbase + def->st_value + rela->r_addend); 371228435Skib reloc_jmpslot(where, target, defobj, obj, (const Elf_Rel *)rela); 372228435Skib break; 373228435Skib 374228435Skib case R_X86_64_IRELATIVE: 375228435Skib break; 376228435Skib 377228435Skib default: 378228435Skib _rtld_error("Unknown relocation type %x in PLT", 379228435Skib (unsigned int)ELF_R_TYPE(rela->r_info)); 380228435Skib return (-1); 381228435Skib } 38248205Sjdp } 38356780Sjdp obj->jmpslots_done = true; 38438816Sdfr return 0; 38538816Sdfr} 386133063Sdfr 387228435Skibint 388228435Skibreloc_iresolve(Obj_Entry *obj, RtldLockState *lockstate) 389228435Skib{ 390228435Skib const Elf_Rela *relalim; 391228435Skib const Elf_Rela *rela; 392228435Skib 393228503Skib if (!obj->irelative) 394228503Skib return (0); 395228435Skib relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize); 396228435Skib for (rela = obj->pltrela; rela < relalim; rela++) { 397228435Skib Elf_Addr *where, target, *ptr; 398228435Skib 399228435Skib switch (ELF_R_TYPE(rela->r_info)) { 400228435Skib case R_X86_64_JMP_SLOT: 401228435Skib break; 402228435Skib 403228435Skib case R_X86_64_IRELATIVE: 404228435Skib ptr = (Elf_Addr *)(obj->relocbase + rela->r_addend); 405228435Skib where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 406228503Skib lock_release(rtld_bind_lock, lockstate); 407228435Skib target = ((Elf_Addr (*)(void))ptr)(); 408228503Skib wlock_acquire(rtld_bind_lock, lockstate); 409228435Skib *where = target; 410228435Skib break; 411228435Skib } 412228435Skib } 413228503Skib obj->irelative = false; 414228435Skib return (0); 415228435Skib} 416228435Skib 417228435Skibint 418233231Skibreloc_gnu_ifunc(Obj_Entry *obj, int flags, RtldLockState *lockstate) 419228435Skib{ 420228435Skib const Elf_Rela *relalim; 421228435Skib const Elf_Rela *rela; 422228435Skib 423228435Skib if (!obj->gnu_ifunc) 424228435Skib return (0); 425228435Skib relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize); 426228435Skib for (rela = obj->pltrela; rela < relalim; rela++) { 427228435Skib Elf_Addr *where, target; 428228435Skib const Elf_Sym *def; 429228435Skib const Obj_Entry *defobj; 430228435Skib 431228435Skib switch (ELF_R_TYPE(rela->r_info)) { 432228435Skib case R_X86_64_JMP_SLOT: 433228435Skib where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 434233231Skib def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, 435233231Skib SYMLOOK_IN_PLT | flags, NULL, lockstate); 436228435Skib if (def == NULL) 437228435Skib return (-1); 438228435Skib if (ELF_ST_TYPE(def->st_info) != STT_GNU_IFUNC) 439228435Skib continue; 440228503Skib lock_release(rtld_bind_lock, lockstate); 441228435Skib target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); 442228503Skib wlock_acquire(rtld_bind_lock, lockstate); 443228435Skib reloc_jmpslot(where, target, defobj, obj, (const Elf_Rel *)rela); 444228435Skib break; 445228435Skib } 446228435Skib } 447228435Skib obj->gnu_ifunc = false; 448228503Skib return (0); 449228435Skib} 450228435Skib 451133063Sdfrvoid 452133063Sdfrallocate_initial_tls(Obj_Entry *objs) 453133063Sdfr{ 454133063Sdfr /* 455133063Sdfr * Fix the size of the static TLS block by using the maximum 456133063Sdfr * offset allocated so far and adding a bit for dynamic modules to 457133063Sdfr * use. 458133063Sdfr */ 459133063Sdfr tls_static_space = tls_last_offset + RTLD_STATIC_TLS_EXTRA; 460133063Sdfr amd64_set_fsbase(allocate_tls(objs, 0, 461157198Sdavidxu 3*sizeof(Elf_Addr), sizeof(Elf_Addr))); 462133063Sdfr} 463133063Sdfr 464133063Sdfrvoid *__tls_get_addr(tls_index *ti) 465133063Sdfr{ 466133063Sdfr Elf_Addr** segbase; 467133063Sdfr 468133063Sdfr __asm __volatile("movq %%fs:0, %0" : "=r" (segbase)); 469133063Sdfr 470133063Sdfr return tls_get_addr_common(&segbase[1], ti->ti_module, ti->ti_offset); 471133063Sdfr} 472