mdreloc.c revision 1.68
1 /* $NetBSD: mdreloc.c,v 1.68 2018/03/29 13:23:39 joerg Exp $ */ 2 3 /*- 4 * Copyright (c) 2000 Eduardo Horvath. 5 * Copyright (c) 1999, 2002 The NetBSD Foundation, Inc. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to The NetBSD Foundation 9 * by Paul Kranenburg and by Charles M. Hannum. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 #ifndef lint 35 __RCSID("$NetBSD: mdreloc.c,v 1.68 2018/03/29 13:23:39 joerg Exp $"); 36 #endif /* not lint */ 37 38 #include <machine/elf_support.h> 39 40 #include <errno.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <unistd.h> 45 46 #include "rtldenv.h" 47 #include "debug.h" 48 #include "rtld.h" 49 50 /* 51 * The following table holds for each relocation type: 52 * - the width in bits of the memory location the relocation 53 * applies to (not currently used) 54 * - the number of bits the relocation value must be shifted to the 55 * right (i.e. discard least significant bits) to fit into 56 * the appropriate field in the instruction word. 57 * - flags indicating whether 58 * * the relocation involves a symbol 59 * * the relocation is relative to the current position 60 * * the relocation is for a GOT entry 61 * * the relocation is relative to the load address 62 * 63 */ 64 #define _RF_S 0x80000000 /* Resolve symbol */ 65 #define _RF_A 0x40000000 /* Use addend */ 66 #define _RF_P 0x20000000 /* Location relative */ 67 #define _RF_G 0x10000000 /* GOT offset */ 68 #define _RF_B 0x08000000 /* Load address relative */ 69 #define _RF_U 0x04000000 /* Unaligned */ 70 #define _RF_SZ(s) (((s) & 0xff) << 8) /* memory target size */ 71 #define _RF_RS(s) ( (s) & 0xff) /* right shift */ 72 static const int reloc_target_flags[R_TYPE(TLS_TPOFF64)+1] = { 73 0, /* NONE */ 74 _RF_S|_RF_A| _RF_SZ(8) | _RF_RS(0), /* RELOC_8 */ 75 _RF_S|_RF_A| _RF_SZ(16) | _RF_RS(0), /* RELOC_16 */ 76 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* RELOC_32 */ 77 _RF_S|_RF_A|_RF_P| _RF_SZ(8) | _RF_RS(0), /* DISP_8 */ 78 _RF_S|_RF_A|_RF_P| _RF_SZ(16) | _RF_RS(0), /* DISP_16 */ 79 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* DISP_32 */ 80 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_30 */ 81 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_22 */ 82 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HI22 */ 83 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 22 */ 84 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 13 */ 85 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LO10 */ 86 _RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT10 */ 87 _RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT13 */ 88 _RF_G| _RF_SZ(32) | _RF_RS(10), /* GOT22 */ 89 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PC10 */ 90 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC22 */ 91 _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WPLT30 */ 92 _RF_SZ(32) | _RF_RS(0), /* COPY */ 93 _RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* GLOB_DAT */ 94 _RF_SZ(32) | _RF_RS(0), /* JMP_SLOT */ 95 _RF_A| _RF_B| _RF_SZ(64) | _RF_RS(0), /* RELATIVE */ 96 _RF_S|_RF_A| _RF_U| _RF_SZ(32) | _RF_RS(0), /* UA_32 */ 97 98 _RF_A| _RF_SZ(32) | _RF_RS(0), /* PLT32 */ 99 _RF_A| _RF_SZ(32) | _RF_RS(10), /* HIPLT22 */ 100 _RF_A| _RF_SZ(32) | _RF_RS(0), /* LOPLT10 */ 101 _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PCPLT32 */ 102 _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PCPLT22 */ 103 _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PCPLT10 */ 104 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 10 */ 105 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 11 */ 106 _RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* 64 */ 107 _RF_S|_RF_A|/*extra*/ _RF_SZ(32) | _RF_RS(0), /* OLO10 */ 108 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(42), /* HH22 */ 109 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(32), /* HM10 */ 110 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* LM22 */ 111 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(42), /* PC_HH22 */ 112 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(32), /* PC_HM10 */ 113 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC_LM22 */ 114 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP16 */ 115 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP19 */ 116 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* GLOB_JMP */ 117 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 7 */ 118 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 5 */ 119 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 6 */ 120 _RF_S|_RF_A|_RF_P| _RF_SZ(64) | _RF_RS(0), /* DISP64 */ 121 _RF_A| _RF_SZ(64) | _RF_RS(0), /* PLT64 */ 122 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HIX22 */ 123 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LOX10 */ 124 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(22), /* H44 */ 125 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(12), /* M44 */ 126 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* L44 */ 127 _RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* REGISTER */ 128 _RF_S|_RF_A| _RF_U| _RF_SZ(64) | _RF_RS(0), /* UA64 */ 129 _RF_S|_RF_A| _RF_U| _RF_SZ(16) | _RF_RS(0), /* UA16 */ 130 /* TLS relocs not represented here! */ 131 }; 132 133 #ifdef RTLD_DEBUG_RELOC 134 static const char *reloc_names[] = { 135 "NONE", "RELOC_8", "RELOC_16", "RELOC_32", "DISP_8", 136 "DISP_16", "DISP_32", "WDISP_30", "WDISP_22", "HI22", 137 "22", "13", "LO10", "GOT10", "GOT13", 138 "GOT22", "PC10", "PC22", "WPLT30", "COPY", 139 "GLOB_DAT", "JMP_SLOT", "RELATIVE", "UA_32", "PLT32", 140 "HIPLT22", "LOPLT10", "LOPLT10", "PCPLT22", "PCPLT32", 141 "10", "11", "64", "OLO10", "HH22", 142 "HM10", "LM22", "PC_HH22", "PC_HM10", "PC_LM22", 143 "WDISP16", "WDISP19", "GLOB_JMP", "7", "5", "6", 144 "DISP64", "PLT64", "HIX22", "LOX10", "H44", "M44", 145 "L44", "REGISTER", "UA64", "UA16", 146 "TLS_GD_HI22", "TLS_GD_LO10", "TLS_GD_ADD", "TLS_GD_CALL", 147 "TLS_LDM_HI22", "TLS_LDM_LO10", "TLS_LDM_ADD", "TLS_LDM_CALL", 148 "TLS_LDO_HIX22", "TLS_LDO_LOX10", "TLS_LDO_ADD", "TLS_IE_HI22", 149 "TLS_IE_LO10", "TLS_IE_LD", "TLS_IE_LDX", "TLS_IE_ADD", "TLS_LE_HIX22", 150 "TLS_LE_LOX10", "TLS_DTPMOD32", "TLS_DTPMOD64", "TLS_DTPOFF32", 151 "TLS_DTPOFF64", "TLS_TPOFF32", "TLS_TPOFF64", 152 }; 153 #endif 154 155 #define RELOC_RESOLVE_SYMBOL(t) ((reloc_target_flags[t] & _RF_S) != 0) 156 #define RELOC_PC_RELATIVE(t) ((reloc_target_flags[t] & _RF_P) != 0) 157 #define RELOC_BASE_RELATIVE(t) ((reloc_target_flags[t] & _RF_B) != 0) 158 #define RELOC_UNALIGNED(t) ((reloc_target_flags[t] & _RF_U) != 0) 159 #define RELOC_USE_ADDEND(t) ((reloc_target_flags[t] & _RF_A) != 0) 160 #define RELOC_TARGET_SIZE(t) ((reloc_target_flags[t] >> 8) & 0xff) 161 #define RELOC_VALUE_RIGHTSHIFT(t) (reloc_target_flags[t] & 0xff) 162 #define RELOC_TLS(t) (t >= R_TYPE(TLS_GD_HI22)) 163 164 static const long reloc_target_bitmask[] = { 165 #define _BM(x) (~(-(1ULL << (x)))) 166 0, /* NONE */ 167 _BM(8), _BM(16), _BM(32), /* RELOC_8, _16, _32 */ 168 _BM(8), _BM(16), _BM(32), /* DISP8, DISP16, DISP32 */ 169 _BM(30), _BM(22), /* WDISP30, WDISP22 */ 170 _BM(22), _BM(22), /* HI22, _22 */ 171 _BM(13), _BM(10), /* RELOC_13, _LO10 */ 172 _BM(10), _BM(13), _BM(22), /* GOT10, GOT13, GOT22 */ 173 _BM(10), _BM(22), /* _PC10, _PC22 */ 174 _BM(30), 0, /* _WPLT30, _COPY */ 175 -1, _BM(32), -1, /* _GLOB_DAT, JMP_SLOT, _RELATIVE */ 176 _BM(32), _BM(32), /* _UA32, PLT32 */ 177 _BM(22), _BM(10), /* _HIPLT22, LOPLT10 */ 178 _BM(32), _BM(22), _BM(10), /* _PCPLT32, _PCPLT22, _PCPLT10 */ 179 _BM(10), _BM(11), -1, /* _10, _11, _64 */ 180 _BM(13), _BM(22), /* _OLO10, _HH22 */ 181 _BM(10), _BM(22), /* _HM10, _LM22 */ 182 _BM(22), _BM(10), _BM(22), /* _PC_HH22, _PC_HM10, _PC_LM22 */ 183 _BM(16), _BM(19), /* _WDISP16, _WDISP19 */ 184 -1, /* GLOB_JMP */ 185 _BM(7), _BM(5), _BM(6), /* _7, _5, _6 */ 186 -1, -1, /* DISP64, PLT64 */ 187 _BM(22), _BM(13), /* HIX22, LOX10 */ 188 _BM(22), _BM(10), _BM(12), /* H44, M44, L44 */ 189 -1, -1, _BM(16), /* REGISTER, UA64, UA16 */ 190 #undef _BM 191 }; 192 #define RELOC_VALUE_BITMASK(t) (reloc_target_bitmask[t]) 193 194 /* 195 * Instruction templates: 196 */ 197 198 199 /* %hi(v)/%lo(v) with variable shift */ 200 #define HIVAL(v, s) (((v) >> (s)) & 0x003fffff) 201 #define LOVAL(v, s) (((v) >> (s)) & 0x000003ff) 202 203 void _rtld_bind_start_0(long, long); 204 void _rtld_bind_start_1(long, long); 205 void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); 206 caddr_t _rtld_bind(const Obj_Entry *, Elf_Word); 207 208 /* 209 * Install rtld function call into this PLT slot. 210 */ 211 #define SAVE 0x9de3bf50 /* i.e. `save %sp,-176,%sp' */ 212 #define SETHI_l0 0x21000000 213 #define SETHI_l1 0x23000000 214 #define OR_l0_l0 0xa0142000 215 #define SLLX_l0_32_l0 0xa12c3020 216 #define OR_l0_l1_l0 0xa0140011 217 #define JMPL_l0_o0 0x91c42000 218 #define MOV_g1_o1 0x92100001 219 220 void _rtld_install_plt(Elf_Word *, Elf_Addr); 221 static inline int _rtld_relocate_plt_object(const Obj_Entry *, 222 const Elf_Rela *, Elf_Addr *); 223 224 void 225 _rtld_install_plt(Elf_Word *pltgot, Elf_Addr proc) 226 { 227 pltgot[0] = SAVE; 228 pltgot[1] = SETHI_l0 | HIVAL(proc, 42); 229 pltgot[2] = SETHI_l1 | HIVAL(proc, 10); 230 pltgot[3] = OR_l0_l0 | LOVAL(proc, 32); 231 pltgot[4] = SLLX_l0_32_l0; 232 pltgot[5] = OR_l0_l1_l0; 233 pltgot[6] = JMPL_l0_o0 | LOVAL(proc, 0); 234 pltgot[7] = MOV_g1_o1; 235 } 236 237 void 238 _rtld_setup_pltgot(const Obj_Entry *obj) 239 { 240 /* 241 * On sparc64 we got troubles. 242 * 243 * Instructions are 4 bytes long. 244 * Elf[64]_Addr is 8 bytes long, so are our pltglot[] 245 * array entries. 246 * Each PLT entry jumps to PLT0 to enter the dynamic 247 * linker. 248 * Loading an arbitrary 64-bit pointer takes 6 249 * instructions and 2 registers. 250 * 251 * Somehow we need to issue a save to get a new stack 252 * frame, load the address of the dynamic linker, and 253 * jump there, in 8 instructions or less. 254 * 255 * Oh, we need to fill out both PLT0 and PLT1. 256 */ 257 { 258 Elf_Word *entry = (Elf_Word *)obj->pltgot; 259 260 /* Install in entries 0 and 1 */ 261 _rtld_install_plt(&entry[0], (Elf_Addr) &_rtld_bind_start_0); 262 _rtld_install_plt(&entry[8], (Elf_Addr) &_rtld_bind_start_1); 263 264 /* 265 * Install the object reference in first slot 266 * of entry 2. 267 */ 268 obj->pltgot[8] = (Elf_Addr) obj; 269 } 270 } 271 272 void 273 _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) 274 { 275 const Elf_Rela *rela = 0, *relalim; 276 Elf_Addr relasz = 0; 277 Elf_Addr *where; 278 279 for (; dynp->d_tag != DT_NULL; dynp++) { 280 switch (dynp->d_tag) { 281 case DT_RELA: 282 rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr); 283 break; 284 case DT_RELASZ: 285 relasz = dynp->d_un.d_val; 286 break; 287 } 288 } 289 relalim = (const Elf_Rela *)((const uint8_t *)rela + relasz); 290 for (; rela < relalim; rela++) { 291 where = (Elf_Addr *)(relocbase + rela->r_offset); 292 *where = (Elf_Addr)(relocbase + rela->r_addend); 293 } 294 } 295 296 int 297 _rtld_relocate_nonplt_objects(Obj_Entry *obj) 298 { 299 const Elf_Rela *rela; 300 const Elf_Sym *def = NULL; 301 const Obj_Entry *defobj = NULL; 302 unsigned long last_symnum = ULONG_MAX; 303 304 for (rela = obj->rela; rela < obj->relalim; rela++) { 305 Elf_Addr *where; 306 Elf_Word type; 307 Elf_Addr value = 0, mask; 308 unsigned long symnum; 309 310 where = (Elf_Addr *) (obj->relocbase + rela->r_offset); 311 312 type = ELF_R_TYPE(rela->r_info); 313 if (type == R_TYPE(NONE)) 314 continue; 315 316 /* OLO10 relocations have extra info */ 317 if ((type & 0x00ff) == R_SPARC_OLO10) 318 type = R_SPARC_OLO10; 319 320 /* We do JMP_SLOTs in _rtld_bind() below */ 321 if (type == R_TYPE(JMP_SLOT)) 322 continue; 323 324 /* IFUNC relocations are handled in _rtld_call_ifunc */ 325 if (type == R_TYPE(IRELATIVE)) { 326 if (obj->ifunc_remaining_nonplt == 0) 327 obj->ifunc_remaining_nonplt = rela - obj->rela + 1; 328 continue; 329 } 330 331 /* COPY relocs are also handled elsewhere */ 332 if (type == R_TYPE(COPY)) 333 continue; 334 335 /* 336 * We use the fact that relocation types are an `enum' 337 * Note: R_SPARC_TLS_TPOFF64 is currently numerically largest. 338 */ 339 if (type > R_TYPE(TLS_TPOFF64)) { 340 dbg(("unknown relocation type %x at %p", type, rela)); 341 return -1; 342 } 343 344 value = rela->r_addend; 345 346 if (RELOC_RESOLVE_SYMBOL(type) || RELOC_TLS(type)) { 347 symnum = ELF_R_SYM(rela->r_info); 348 if (last_symnum != symnum) { 349 last_symnum = symnum; 350 def = _rtld_find_symdef(symnum, obj, &defobj, 351 false); 352 if (def == NULL) 353 return -1; 354 } 355 } 356 357 /* 358 * Handle TLS relocations here, they are different. 359 */ 360 if (RELOC_TLS(type)) { 361 switch (type) { 362 case R_TYPE(TLS_DTPMOD64): 363 *where = (Elf64_Addr)defobj->tlsindex; 364 365 rdbg(("TLS_DTPMOD64 %s in %s --> %p", 366 obj->strtab + 367 obj->symtab[symnum].st_name, 368 obj->path, (void *)*where)); 369 370 break; 371 372 case R_TYPE(TLS_DTPOFF64): 373 *where = (Elf64_Addr)(def->st_value 374 + rela->r_addend); 375 376 rdbg(("DTPOFF64 %s in %s --> %p", 377 obj->strtab + 378 obj->symtab[symnum].st_name, 379 obj->path, (void *)*where)); 380 381 break; 382 383 case R_TYPE(TLS_TPOFF64): 384 if (!defobj->tls_done && 385 _rtld_tls_offset_allocate(obj)) 386 return -1; 387 388 *where = (Elf64_Addr)(def->st_value - 389 defobj->tlsoffset + rela->r_addend); 390 391 rdbg(("TLS_TPOFF64 %s in %s --> %p", 392 obj->strtab + obj->symtab[symnum].st_name, 393 obj->path, (void *)*where)); 394 395 break; 396 } 397 continue; 398 } 399 400 /* 401 * Handle relative relocs here, as an optimization. 402 */ 403 if (type == R_TYPE(RELATIVE)) { 404 *where = (Elf_Addr)(obj->relocbase + value); 405 rdbg(("RELATIVE in %s --> %p", obj->path, 406 (void *)*where)); 407 continue; 408 } 409 410 if (RELOC_RESOLVE_SYMBOL(type)) { 411 /* Add in the symbol's absolute address */ 412 value += (Elf_Addr)(defobj->relocbase + def->st_value); 413 } 414 415 if (type == R_SPARC_OLO10) { 416 value = (value & 0x3ff) 417 + (((Elf64_Xword)rela->r_info<<32)>>40); 418 } 419 420 if (RELOC_PC_RELATIVE(type)) { 421 value -= (Elf_Addr)where; 422 } 423 424 if (RELOC_BASE_RELATIVE(type)) { 425 /* 426 * Note that even though sparcs use `Elf_rela' 427 * exclusively we still need the implicit memory addend 428 * in relocations referring to GOT entries. 429 * Undoubtedly, someone f*cked this up in the distant 430 * past, and now we're stuck with it in the name of 431 * compatibility for all eternity.. 432 * 433 * In any case, the implicit and explicit should be 434 * mutually exclusive. We provide a check for that 435 * here. 436 */ 437 #ifdef DIAGNOSTIC 438 if (value != 0 && *where != 0) { 439 xprintf("BASE_REL(%s): where=%p, *where 0x%lx, " 440 "addend=0x%lx, base %p\n", 441 obj->path, where, *where, 442 rela->r_addend, obj->relocbase); 443 } 444 #endif 445 /* XXXX -- apparently we ignore the preexisting value */ 446 value += (Elf_Addr)(obj->relocbase); 447 } 448 449 mask = RELOC_VALUE_BITMASK(type); 450 value >>= RELOC_VALUE_RIGHTSHIFT(type); 451 value &= mask; 452 453 if (RELOC_UNALIGNED(type)) { 454 /* Handle unaligned relocations. */ 455 Elf_Addr tmp = 0; 456 char *ptr = (char *)where; 457 int i, size = RELOC_TARGET_SIZE(type)/8; 458 459 /* Read it in one byte at a time. */ 460 for (i=0; i<size; i++) 461 tmp = (tmp << 8) | ptr[i]; 462 463 tmp &= ~mask; 464 tmp |= value; 465 466 /* Write it back out. */ 467 for (i=0; i<size; i++) 468 ptr[i] = ((tmp >> (8*i)) & 0xff); 469 #ifdef RTLD_DEBUG_RELOC 470 value = (Elf_Addr)tmp; 471 #endif 472 473 } else if (RELOC_TARGET_SIZE(type) > 32) { 474 *where &= ~mask; 475 *where |= value; 476 #ifdef RTLD_DEBUG_RELOC 477 value = (Elf_Addr)*where; 478 #endif 479 } else { 480 Elf32_Addr *where32 = (Elf32_Addr *)where; 481 482 *where32 &= ~mask; 483 *where32 |= value; 484 #ifdef RTLD_DEBUG_RELOC 485 value = (Elf_Addr)*where32; 486 #endif 487 } 488 489 #ifdef RTLD_DEBUG_RELOC 490 if (RELOC_RESOLVE_SYMBOL(type)) { 491 rdbg(("%s %s in %s --> %p in %s", reloc_names[type], 492 obj->strtab + obj->symtab[symnum].st_name, 493 obj->path, (void *)value, defobj->path)); 494 } else { 495 rdbg(("%s in %s --> %p", reloc_names[type], 496 obj->path, (void *)value)); 497 } 498 #endif 499 } 500 return (0); 501 } 502 503 int 504 _rtld_relocate_plt_lazy(Obj_Entry *obj) 505 { 506 const Elf_Rela *rela; 507 508 for (rela = obj->pltrelalim; rela-- > obj->pltrela; ) { 509 if (ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_IREL)) 510 obj->ifunc_remaining = obj->pltrelalim - rela + 1; 511 } 512 513 return 0; 514 } 515 516 caddr_t 517 _rtld_bind(const Obj_Entry *obj, Elf_Word reloff) 518 { 519 const Elf_Rela *rela = obj->pltrela + reloff; 520 Elf_Addr result; 521 int err; 522 523 result = 0; /* XXX gcc */ 524 525 if (ELF_R_TYPE(obj->pltrela->r_info) == R_TYPE(JMP_SLOT) || 526 ELF_R_TYPE(obj->pltrela->r_info) == R_TYPE(JMP_IREL)) { 527 /* 528 * XXXX 529 * 530 * The first four PLT entries are reserved. There is some 531 * disagreement whether they should have associated relocation 532 * entries. Both the SPARC 32-bit and 64-bit ELF 533 * specifications say that they should have relocation entries, 534 * but the 32-bit SPARC binutils do not generate them, and now 535 * the 64-bit SPARC binutils have stopped generating them too. 536 * 537 * So, to provide binary compatibility, we will check the first 538 * entry, if it is reserved it should not be of the type 539 * JMP_SLOT or JMP_REL. If it is either of those, then 540 * the 4 reserved entries were not generated and our index 541 * is 4 entries too far. 542 */ 543 rela -= 4; 544 } 545 546 _rtld_shared_enter(); 547 err = _rtld_relocate_plt_object(obj, rela, &result); 548 if (err) 549 _rtld_die(); 550 _rtld_shared_exit(); 551 552 return (caddr_t)result; 553 } 554 555 int 556 _rtld_relocate_plt_objects(const Obj_Entry *obj) 557 { 558 const Elf_Rela *rela; 559 560 rela = obj->pltrela; 561 562 /* 563 * Check for first four reserved entries - and skip them. 564 * See above for details. 565 */ 566 if (ELF_R_TYPE(obj->pltrela->r_info) != R_TYPE(JMP_SLOT) && 567 ELF_R_TYPE(obj->pltrela->r_info) != R_TYPE(JMP_IREL)) 568 rela += 4; 569 570 for (; rela < obj->pltrelalim; rela++) 571 if (_rtld_relocate_plt_object(obj, rela, NULL) < 0) 572 return -1; 573 574 return 0; 575 } 576 577 static inline void 578 _rtld_write_plt(Elf_Word *where, Elf_Addr value, const Elf_Rela *rela, 579 const Obj_Entry *obj) 580 { 581 if (rela && rela->r_addend) { 582 Elf_Addr *ptr = (Elf_Addr *)where; 583 /* 584 * This entry is >= 32768. The relocations points to a 585 * PC-relative pointer to the bind_0 stub at the top of the 586 * PLT section. Update it to point to the target function. 587 */ 588 ptr[0] += value - (Elf_Addr)obj->pltgot; 589 } else { 590 sparc_write_branch(where + 1, (void *)value); 591 } 592 } 593 594 /* 595 * New inline function that is called by _rtld_relocate_plt_object and 596 * _rtld_bind 597 */ 598 static inline int 599 _rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, 600 Elf_Addr *tp) 601 { 602 Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset); 603 const Elf_Sym *def; 604 const Obj_Entry *defobj; 605 Elf_Addr value; 606 unsigned long info = rela->r_info; 607 608 if (ELF_R_TYPE(info) == R_TYPE(JMP_IREL)) 609 return 0; 610 611 assert(ELF_R_TYPE(info) == R_TYPE(JMP_SLOT)); 612 613 def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL); 614 if (__predict_false(def == NULL)) 615 return -1; 616 if (__predict_false(def == &_rtld_sym_zero)) 617 return 0; 618 619 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) { 620 if (tp == NULL) 621 return 0; 622 value = _rtld_resolve_ifunc(defobj, def); 623 } else { 624 value = (Elf_Addr)(defobj->relocbase + def->st_value); 625 } 626 rdbg(("bind now/fixup in %s at %p --> new=%p", 627 defobj->strtab + def->st_name, (void*)where, (void *)value)); 628 629 _rtld_write_plt(where, value, rela, obj); 630 631 if (tp) 632 *tp = value; 633 634 return 0; 635 } 636 637 void 638 _rtld_call_ifunc(Obj_Entry *obj, sigset_t *mask, u_int cur_objgen) 639 { 640 const Elf_Rela *rela; 641 Elf_Addr *where; 642 Elf_Word *where2; 643 Elf_Addr target; 644 645 while (obj->ifunc_remaining > 0 && _rtld_objgen == cur_objgen) { 646 rela = obj->pltrelalim - --obj->ifunc_remaining; 647 if (ELF_R_TYPE(rela->r_info) != R_TYPE(JMP_IREL)) 648 continue; 649 where2 = (Elf_Word *)(obj->relocbase + rela->r_offset); 650 target = (Elf_Addr)(obj->relocbase + rela->r_addend); 651 _rtld_exclusive_exit(mask); 652 target = _rtld_resolve_ifunc2(obj, target); 653 _rtld_exclusive_enter(mask); 654 sparc_write_branch(where2 + 1, (void *)target); 655 } 656 657 while (obj->ifunc_remaining_nonplt > 0 && _rtld_objgen == cur_objgen) { 658 rela = obj->relalim - --obj->ifunc_remaining_nonplt; 659 if (ELF_R_TYPE(rela->r_info) != R_TYPE(IRELATIVE)) 660 continue; 661 where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 662 target = (Elf_Addr)(obj->relocbase + rela->r_addend); 663 _rtld_exclusive_exit(mask); 664 target = _rtld_resolve_ifunc2(obj, target); 665 _rtld_exclusive_enter(mask); 666 if (*where != target) 667 *where = target; 668 } 669 } 670
Indexes created Tue Sep 30 17:09:57 GMT 2025