1 /* $NetBSD: mdreloc.c,v 1.72 2024/08/03 21:59:58 riastradh 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 /* 34 * SPARC ELF relocations. 35 * 36 * Reference: 37 * 38 * SPARC Compliance Definition 2.4.1 39 * http://sparc.org/wp-content/uploads/2014/01/SCD.2.4.1.pdf.gz 40 */ 41 42 #include <sys/cdefs.h> 43 #ifndef lint 44 __RCSID("$NetBSD: mdreloc.c,v 1.72 2024/08/03 21:59:58 riastradh Exp $"); 45 #endif /* not lint */ 46 47 #include <machine/elf_support.h> 48 49 #include <errno.h> 50 #include <stdio.h> 51 #include <stdlib.h> 52 #include <string.h> 53 #include <unistd.h> 54 55 #include "rtldenv.h" 56 #include "debug.h" 57 #include "rtld.h" 58 59 /* 60 * The following table holds for each relocation type: 61 * - the width in bits of the memory location the relocation 62 * applies to (not currently used) 63 * - the number of bits the relocation value must be shifted to the 64 * right (i.e. discard least significant bits) to fit into 65 * the appropriate field in the instruction word. 66 * - flags indicating whether 67 * * the relocation involves a symbol 68 * * the relocation is relative to the current position 69 * * the relocation is for a GOT entry 70 * * the relocation is relative to the load address 71 * 72 */ 73 #define _RF_S 0x80000000 /* Resolve symbol */ 74 #define _RF_A 0x40000000 /* Use addend */ 75 #define _RF_P 0x20000000 /* Location relative */ 76 #define _RF_G 0x10000000 /* GOT offset */ 77 #define _RF_B 0x08000000 /* Load address relative */ 78 #define _RF_U 0x04000000 /* Unaligned */ 79 #define _RF_SZ(s) (((s) & 0xff) << 8) /* memory target size */ 80 #define _RF_RS(s) ( (s) & 0xff) /* right shift */ 81 static const int reloc_target_flags[R_TYPE(TLS_TPOFF64)+1] = { 82 0, /* NONE */ 83 _RF_S|_RF_A| _RF_SZ(8) | _RF_RS(0), /* RELOC_8 */ 84 _RF_S|_RF_A| _RF_SZ(16) | _RF_RS(0), /* RELOC_16 */ 85 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* RELOC_32 */ 86 _RF_S|_RF_A|_RF_P| _RF_SZ(8) | _RF_RS(0), /* DISP_8 */ 87 _RF_S|_RF_A|_RF_P| _RF_SZ(16) | _RF_RS(0), /* DISP_16 */ 88 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* DISP_32 */ 89 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_30 */ 90 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_22 */ 91 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HI22 */ 92 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 22 */ 93 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 13 */ 94 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LO10 */ 95 _RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT10 */ 96 _RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT13 */ 97 _RF_G| _RF_SZ(32) | _RF_RS(10), /* GOT22 */ 98 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PC10 */ 99 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC22 */ 100 _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WPLT30 */ 101 _RF_SZ(32) | _RF_RS(0), /* COPY */ 102 _RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* GLOB_DAT */ 103 _RF_SZ(32) | _RF_RS(0), /* JMP_SLOT */ 104 _RF_A| _RF_B| _RF_SZ(64) | _RF_RS(0), /* RELATIVE */ 105 _RF_S|_RF_A| _RF_U| _RF_SZ(32) | _RF_RS(0), /* UA_32 */ 106 107 _RF_A| _RF_SZ(32) | _RF_RS(0), /* PLT32 */ 108 _RF_A| _RF_SZ(32) | _RF_RS(10), /* HIPLT22 */ 109 _RF_A| _RF_SZ(32) | _RF_RS(0), /* LOPLT10 */ 110 _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PCPLT32 */ 111 _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PCPLT22 */ 112 _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PCPLT10 */ 113 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 10 */ 114 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 11 */ 115 _RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* 64 */ 116 _RF_S|_RF_A|/*extra*/ _RF_SZ(32) | _RF_RS(0), /* OLO10 */ 117 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(42), /* HH22 */ 118 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(32), /* HM10 */ 119 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* LM22 */ 120 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(42), /* PC_HH22 */ 121 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(32), /* PC_HM10 */ 122 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC_LM22 */ 123 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP16 */ 124 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP19 */ 125 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* GLOB_JMP */ 126 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 7 */ 127 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 5 */ 128 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 6 */ 129 _RF_S|_RF_A|_RF_P| _RF_SZ(64) | _RF_RS(0), /* DISP64 */ 130 _RF_A| _RF_SZ(64) | _RF_RS(0), /* PLT64 */ 131 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HIX22 */ 132 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LOX10 */ 133 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(22), /* H44 */ 134 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(12), /* M44 */ 135 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* L44 */ 136 _RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* REGISTER */ 137 _RF_S|_RF_A| _RF_U| _RF_SZ(64) | _RF_RS(0), /* UA64 */ 138 _RF_S|_RF_A| _RF_U| _RF_SZ(16) | _RF_RS(0), /* UA16 */ 139 /* TLS relocs not represented here! */ 140 }; 141 142 #ifdef RTLD_DEBUG_RELOC 143 static const char *reloc_names[] = { 144 "NONE", "RELOC_8", "RELOC_16", "RELOC_32", "DISP_8", 145 "DISP_16", "DISP_32", "WDISP_30", "WDISP_22", "HI22", 146 "22", "13", "LO10", "GOT10", "GOT13", 147 "GOT22", "PC10", "PC22", "WPLT30", "COPY", 148 "GLOB_DAT", "JMP_SLOT", "RELATIVE", "UA_32", "PLT32", 149 "HIPLT22", "LOPLT10", "LOPLT10", "PCPLT22", "PCPLT32", 150 "10", "11", "64", "OLO10", "HH22", 151 "HM10", "LM22", "PC_HH22", "PC_HM10", "PC_LM22", 152 "WDISP16", "WDISP19", "GLOB_JMP", "7", "5", "6", 153 "DISP64", "PLT64", "HIX22", "LOX10", "H44", "M44", 154 "L44", "REGISTER", "UA64", "UA16", 155 "TLS_GD_HI22", "TLS_GD_LO10", "TLS_GD_ADD", "TLS_GD_CALL", 156 "TLS_LDM_HI22", "TLS_LDM_LO10", "TLS_LDM_ADD", "TLS_LDM_CALL", 157 "TLS_LDO_HIX22", "TLS_LDO_LOX10", "TLS_LDO_ADD", "TLS_IE_HI22", 158 "TLS_IE_LO10", "TLS_IE_LD", "TLS_IE_LDX", "TLS_IE_ADD", "TLS_LE_HIX22", 159 "TLS_LE_LOX10", "TLS_DTPMOD32", "TLS_DTPMOD64", "TLS_DTPOFF32", 160 "TLS_DTPOFF64", "TLS_TPOFF32", "TLS_TPOFF64", 161 }; 162 #endif 163 164 #define RELOC_RESOLVE_SYMBOL(t) ((reloc_target_flags[t] & _RF_S) != 0) 165 #define RELOC_PC_RELATIVE(t) ((reloc_target_flags[t] & _RF_P) != 0) 166 #define RELOC_BASE_RELATIVE(t) ((reloc_target_flags[t] & _RF_B) != 0) 167 #define RELOC_UNALIGNED(t) ((reloc_target_flags[t] & _RF_U) != 0) 168 #define RELOC_USE_ADDEND(t) ((reloc_target_flags[t] & _RF_A) != 0) 169 #define RELOC_TARGET_SIZE(t) ((reloc_target_flags[t] >> 8) & 0xff) 170 #define RELOC_VALUE_RIGHTSHIFT(t) (reloc_target_flags[t] & 0xff) 171 #define RELOC_TLS(t) (t >= R_TYPE(TLS_GD_HI22)) 172 173 static const long reloc_target_bitmask[] = { 174 #define _BM(x) (~(-(1ULL << (x)))) 175 0, /* NONE */ 176 _BM(8), _BM(16), _BM(32), /* RELOC_8, _16, _32 */ 177 _BM(8), _BM(16), _BM(32), /* DISP8, DISP16, DISP32 */ 178 _BM(30), _BM(22), /* WDISP30, WDISP22 */ 179 _BM(22), _BM(22), /* HI22, _22 */ 180 _BM(13), _BM(10), /* RELOC_13, _LO10 */ 181 _BM(10), _BM(13), _BM(22), /* GOT10, GOT13, GOT22 */ 182 _BM(10), _BM(22), /* _PC10, _PC22 */ 183 _BM(30), 0, /* _WPLT30, _COPY */ 184 -1, _BM(32), -1, /* _GLOB_DAT, JMP_SLOT, _RELATIVE */ 185 _BM(32), _BM(32), /* _UA32, PLT32 */ 186 _BM(22), _BM(10), /* _HIPLT22, LOPLT10 */ 187 _BM(32), _BM(22), _BM(10), /* _PCPLT32, _PCPLT22, _PCPLT10 */ 188 _BM(10), _BM(11), -1, /* _10, _11, _64 */ 189 _BM(13), _BM(22), /* _OLO10, _HH22 */ 190 _BM(10), _BM(22), /* _HM10, _LM22 */ 191 _BM(22), _BM(10), _BM(22), /* _PC_HH22, _PC_HM10, _PC_LM22 */ 192 _BM(16), _BM(19), /* _WDISP16, _WDISP19 */ 193 -1, /* GLOB_JMP */ 194 _BM(7), _BM(5), _BM(6), /* _7, _5, _6 */ 195 -1, -1, /* DISP64, PLT64 */ 196 _BM(22), _BM(13), /* HIX22, LOX10 */ 197 _BM(22), _BM(10), _BM(12), /* H44, M44, L44 */ 198 -1, -1, _BM(16), /* REGISTER, UA64, UA16 */ 199 #undef _BM 200 }; 201 #define RELOC_VALUE_BITMASK(t) (reloc_target_bitmask[t]) 202 203 /* 204 * Instruction templates: 205 */ 206 207 208 /* %hi(v)/%lo(v) with variable shift */ 209 #define HIVAL(v, s) (((v) >> (s)) & 0x003fffff) 210 #define LOVAL(v, s) (((v) >> (s)) & 0x000003ff) 211 212 void _rtld_bind_start_0(long, long); 213 void _rtld_bind_start_1(long, long); 214 void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); 215 caddr_t _rtld_bind(const Obj_Entry *, Elf_Word); 216 217 /* 218 * Install rtld function call into this PLT slot. 219 */ 220 #define SAVE 0x9de3bf50 /* i.e. `save %sp,-176,%sp' */ 221 #define SETHI_l0 0x21000000 222 #define SETHI_l1 0x23000000 223 #define OR_l0_l0 0xa0142000 224 #define SLLX_l0_32_l0 0xa12c3020 225 #define OR_l0_l1_l0 0xa0140011 226 #define JMPL_l0_o0 0x91c42000 227 #define MOV_g1_o1 0x92100001 228 229 void _rtld_install_plt(Elf_Word *, Elf_Addr); 230 static inline int _rtld_relocate_plt_object(const Obj_Entry *, 231 const Elf_Rela *, Elf_Addr *); 232 233 void 234 _rtld_install_plt(Elf_Word *pltgot, Elf_Addr proc) 235 { 236 pltgot[0] = SAVE; 237 pltgot[1] = SETHI_l0 | HIVAL(proc, 42); 238 pltgot[2] = SETHI_l1 | HIVAL(proc, 10); 239 pltgot[3] = OR_l0_l0 | LOVAL(proc, 32); 240 pltgot[4] = SLLX_l0_32_l0; 241 pltgot[5] = OR_l0_l1_l0; 242 pltgot[6] = JMPL_l0_o0 | LOVAL(proc, 0); 243 pltgot[7] = MOV_g1_o1; 244 } 245 246 void 247 _rtld_setup_pltgot(const Obj_Entry *obj) 248 { 249 /* 250 * On sparc64 we got troubles. 251 * 252 * Instructions are 4 bytes long. 253 * Elf[64]_Addr is 8 bytes long, so are our pltglot[] 254 * array entries. 255 * Each PLT entry jumps to PLT0 to enter the dynamic 256 * linker. 257 * Loading an arbitrary 64-bit pointer takes 6 258 * instructions and 2 registers. 259 * 260 * Somehow we need to issue a save to get a new stack 261 * frame, load the address of the dynamic linker, and 262 * jump there, in 8 instructions or less. 263 * 264 * Oh, we need to fill out both PLT0 and PLT1. 265 */ 266 { 267 Elf_Word *entry = (Elf_Word *)obj->pltgot; 268 269 /* Install in entries 0 and 1 */ 270 _rtld_install_plt(&entry[0], (Elf_Addr) &_rtld_bind_start_0); 271 _rtld_install_plt(&entry[8], (Elf_Addr) &_rtld_bind_start_1); 272 273 /* 274 * Install the object reference in first slot 275 * of entry 2. 276 */ 277 obj->pltgot[8] = (Elf_Addr) obj; 278 } 279 } 280 281 void 282 _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) 283 { 284 const Elf_Rela *rela = 0, *relalim; 285 Elf_Addr relasz = 0; 286 Elf_Addr *where; 287 288 for (; dynp->d_tag != DT_NULL; dynp++) { 289 switch (dynp->d_tag) { 290 case DT_RELA: 291 rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr); 292 break; 293 case DT_RELASZ: 294 relasz = dynp->d_un.d_val; 295 break; 296 } 297 } 298 relalim = (const Elf_Rela *)((const uint8_t *)rela + relasz); 299 for (; rela < relalim; rela++) { 300 where = (Elf_Addr *)(relocbase + rela->r_offset); 301 *where = (Elf_Addr)(relocbase + rela->r_addend); 302 } 303 } 304 305 int 306 _rtld_relocate_nonplt_objects(Obj_Entry *obj) 307 { 308 const Elf_Rela *rela; 309 const Elf_Sym *def = NULL; 310 const Obj_Entry *defobj = NULL; 311 unsigned long last_symnum = ULONG_MAX; 312 313 for (rela = obj->rela; rela < obj->relalim; rela++) { 314 Elf_Addr *where; 315 Elf_Word type; 316 Elf_Addr value = 0, mask; 317 unsigned long symnum; 318 319 where = (Elf_Addr *) (obj->relocbase + rela->r_offset); 320 321 type = ELF_R_TYPE(rela->r_info); 322 if (type == R_TYPE(NONE)) 323 continue; 324 325 /* OLO10 relocations have extra info */ 326 if ((type & 0x00ff) == R_SPARC_OLO10) 327 type = R_SPARC_OLO10; 328 329 /* We do JMP_SLOTs in _rtld_bind() below */ 330 if (type == R_TYPE(JMP_SLOT)) 331 continue; 332 333 /* IFUNC relocations are handled in _rtld_call_ifunc */ 334 if (type == R_TYPE(IRELATIVE)) { 335 if (obj->ifunc_remaining_nonplt == 0) { 336 obj->ifunc_remaining_nonplt = 337 obj->relalim - rela; 338 } 339 continue; 340 } 341 342 /* COPY relocs are also handled elsewhere */ 343 if (type == R_TYPE(COPY)) 344 continue; 345 346 /* 347 * We use the fact that relocation types are an `enum' 348 * Note: R_SPARC_TLS_TPOFF64 is currently numerically largest. 349 */ 350 if (type > R_TYPE(TLS_TPOFF64)) { 351 dbg(("unknown relocation type %x at %p", type, rela)); 352 return -1; 353 } 354 355 value = rela->r_addend; 356 357 if (RELOC_RESOLVE_SYMBOL(type) || RELOC_TLS(type)) { 358 symnum = ELF_R_SYM(rela->r_info); 359 if (last_symnum != symnum) { 360 last_symnum = symnum; 361 def = _rtld_find_symdef(symnum, obj, &defobj, 362 false); 363 if (def == NULL) 364 return -1; 365 } 366 } 367 368 /* 369 * Handle TLS relocations here, they are different. 370 */ 371 if (RELOC_TLS(type)) { 372 switch (type) { 373 case R_TYPE(TLS_DTPMOD64): 374 *where = (Elf64_Addr)defobj->tlsindex; 375 376 rdbg(("TLS_DTPMOD64 %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_DTPOFF64): 384 *where = (Elf64_Addr)(def->st_value 385 + rela->r_addend); 386 387 rdbg(("DTPOFF64 %s in %s --> %p", 388 obj->strtab + 389 obj->symtab[symnum].st_name, 390 obj->path, (void *)*where)); 391 392 break; 393 394 case R_TYPE(TLS_TPOFF64): 395 if (!defobj->tls_static && 396 _rtld_tls_offset_allocate(__UNCONST(defobj))) 397 return -1; 398 399 *where = (Elf64_Addr)(def->st_value - 400 defobj->tlsoffset + rela->r_addend); 401 402 rdbg(("TLS_TPOFF64 %s in %s --> %p", 403 obj->strtab + obj->symtab[symnum].st_name, 404 obj->path, (void *)*where)); 405 406 break; 407 } 408 continue; 409 } 410 411 /* 412 * Handle relative relocs here, as an optimization. 413 */ 414 if (type == R_TYPE(RELATIVE)) { 415 *where = (Elf_Addr)(obj->relocbase + value); 416 rdbg(("RELATIVE in %s --> %p", obj->path, 417 (void *)*where)); 418 continue; 419 } 420 421 if (RELOC_RESOLVE_SYMBOL(type)) { 422 /* Add in the symbol's absolute address */ 423 value += (Elf_Addr)(defobj->relocbase + def->st_value); 424 } 425 426 if (type == R_SPARC_OLO10) { 427 value = (value & 0x3ff) 428 + (((Elf64_Xword)rela->r_info<<32)>>40); 429 } 430 431 if (RELOC_PC_RELATIVE(type)) { 432 value -= (Elf_Addr)where; 433 } 434 435 if (RELOC_BASE_RELATIVE(type)) { 436 /* 437 * Note that even though sparcs use `Elf_rela' 438 * exclusively we still need the implicit memory addend 439 * in relocations referring to GOT entries. 440 * Undoubtedly, someone f*cked this up in the distant 441 * past, and now we're stuck with it in the name of 442 * compatibility for all eternity.. 443 * 444 * In any case, the implicit and explicit should be 445 * mutually exclusive. We provide a check for that 446 * here. 447 */ 448 #ifdef DIAGNOSTIC 449 if (value != 0 && *where != 0) { 450 xprintf("BASE_REL(%s): where=%p, *where 0x%lx, " 451 "addend=0x%lx, base %p\n", 452 obj->path, where, *where, 453 rela->r_addend, obj->relocbase); 454 } 455 #endif 456 /* XXXX -- apparently we ignore the preexisting value */ 457 value += (Elf_Addr)(obj->relocbase); 458 } 459 460 mask = RELOC_VALUE_BITMASK(type); 461 value >>= RELOC_VALUE_RIGHTSHIFT(type); 462 value &= mask; 463 464 if (RELOC_UNALIGNED(type)) { 465 /* Handle unaligned relocations. */ 466 Elf_Addr tmp = 0; 467 char *ptr = (char *)where; 468 int i, size = RELOC_TARGET_SIZE(type)/8; 469 470 /* Read it in one byte at a time. */ 471 for (i=0; i<size; i++) 472 tmp = (tmp << 8) | ptr[i]; 473 474 tmp &= ~mask; 475 tmp |= value; 476 477 /* Write it back out. */ 478 for (i=0; i<size; i++) 479 ptr[i] = ((tmp >> (8*i)) & 0xff); 480 #ifdef RTLD_DEBUG_RELOC 481 value = (Elf_Addr)tmp; 482 #endif 483 484 } else if (RELOC_TARGET_SIZE(type) > 32) { 485 *where &= ~mask; 486 *where |= value; 487 #ifdef RTLD_DEBUG_RELOC 488 value = (Elf_Addr)*where; 489 #endif 490 } else { 491 Elf32_Addr *where32 = (Elf32_Addr *)where; 492 493 *where32 &= ~mask; 494 *where32 |= value; 495 #ifdef RTLD_DEBUG_RELOC 496 value = (Elf_Addr)*where32; 497 #endif 498 } 499 500 #ifdef RTLD_DEBUG_RELOC 501 if (RELOC_RESOLVE_SYMBOL(type)) { 502 rdbg(("%s %s in %s --> %p in %s", reloc_names[type], 503 obj->strtab + obj->symtab[symnum].st_name, 504 obj->path, (void *)value, defobj->path)); 505 } else { 506 rdbg(("%s in %s --> %p", reloc_names[type], 507 obj->path, (void *)value)); 508 } 509 #endif 510 } 511 return (0); 512 } 513 514 int 515 _rtld_relocate_plt_lazy(Obj_Entry *obj) 516 { 517 const Elf_Rela *rela; 518 519 for (rela = obj->pltrelalim; rela-- > obj->pltrela; ) { 520 if (ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_IREL)) 521 obj->ifunc_remaining = obj->pltrelalim - rela + 1; 522 } 523 524 return 0; 525 } 526 527 caddr_t 528 _rtld_bind(const Obj_Entry *obj, Elf_Word reloff) 529 { 530 const Elf_Rela *rela = obj->pltrela + reloff; 531 Elf_Addr result; 532 int err; 533 534 result = 0; /* XXX gcc */ 535 536 if (ELF_R_TYPE(obj->pltrela->r_info) == R_TYPE(JMP_SLOT) || 537 ELF_R_TYPE(obj->pltrela->r_info) == R_TYPE(JMP_IREL)) { 538 /* 539 * XXXX 540 * 541 * The first four PLT entries are reserved. There is some 542 * disagreement whether they should have associated relocation 543 * entries. Both the SPARC 32-bit and 64-bit ELF 544 * specifications say that they should have relocation entries, 545 * but the 32-bit SPARC binutils do not generate them, and now 546 * the 64-bit SPARC binutils have stopped generating them too. 547 * 548 * So, to provide binary compatibility, we will check the first 549 * entry, if it is reserved it should not be of the type 550 * JMP_SLOT or JMP_REL. If it is either of those, then 551 * the 4 reserved entries were not generated and our index 552 * is 4 entries too far. 553 */ 554 rela -= 4; 555 } 556 557 _rtld_shared_enter(); 558 err = _rtld_relocate_plt_object(obj, rela, &result); 559 if (err) 560 _rtld_die(); 561 _rtld_shared_exit(); 562 563 return (caddr_t)result; 564 } 565 566 int 567 _rtld_relocate_plt_objects(const Obj_Entry *obj) 568 { 569 const Elf_Rela *rela; 570 571 rela = obj->pltrela; 572 573 /* 574 * Check for first four reserved entries - and skip them. 575 * See above for details. 576 */ 577 if (ELF_R_TYPE(obj->pltrela->r_info) != R_TYPE(JMP_SLOT) && 578 ELF_R_TYPE(obj->pltrela->r_info) != R_TYPE(JMP_IREL)) 579 rela += 4; 580 581 for (; rela < obj->pltrelalim; rela++) 582 if (_rtld_relocate_plt_object(obj, rela, NULL) < 0) 583 return -1; 584 585 return 0; 586 } 587 588 static inline void 589 _rtld_write_plt(Elf_Word *where, Elf_Addr value, const Elf_Rela *rela, 590 const Obj_Entry *obj) 591 { 592 if (rela && rela->r_addend) { 593 Elf_Addr *ptr = (Elf_Addr *)where; 594 /* 595 * This entry is >= 32768. The relocations points to a 596 * PC-relative pointer to the bind_0 stub at the top of the 597 * PLT section. Update it to point to the target function. 598 */ 599 ptr[0] += value - (Elf_Addr)obj->pltgot; 600 } else { 601 sparc_write_branch(where + 1, (void *)value); 602 } 603 } 604 605 /* 606 * New inline function that is called by _rtld_relocate_plt_object and 607 * _rtld_bind 608 */ 609 static inline int 610 _rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, 611 Elf_Addr *tp) 612 { 613 Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset); 614 const Elf_Sym *def; 615 const Obj_Entry *defobj; 616 Elf_Addr value; 617 unsigned long info = rela->r_info; 618 619 if (ELF_R_TYPE(info) == R_TYPE(JMP_IREL)) 620 return 0; 621 622 assert(ELF_R_TYPE(info) == R_TYPE(JMP_SLOT)); 623 624 def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL); 625 if (__predict_false(def == NULL)) 626 return -1; 627 if (__predict_false(def == &_rtld_sym_zero)) 628 return 0; 629 630 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) { 631 if (tp == NULL) 632 return 0; 633 value = _rtld_resolve_ifunc(defobj, def); 634 } else { 635 value = (Elf_Addr)(defobj->relocbase + def->st_value); 636 } 637 rdbg(("bind now/fixup in %s at %p --> new=%p", 638 defobj->strtab + def->st_name, (void*)where, (void *)value)); 639 640 _rtld_write_plt(where, value, rela, obj); 641 642 if (tp) 643 *tp = value; 644 645 return 0; 646 } 647
Indexes created Sat Sep 27 14:09:57 GMT 2025