1 /* $NetBSD: mdreloc.c,v 1.23 2003/07/26 15:04:38 mrg Exp $ */ 2 3 #include <sys/cdefs.h> 4 __FBSDID("$FreeBSD$"); 5 #include <sys/param.h> 6 #include <sys/mman.h> 7 8 #include <errno.h> 9 #include <stdio.h> 10 #include <stdlib.h> 11 #include <string.h> 12 #include <unistd.h> 13 14 #include "machine/sysarch.h" 15 16 #include "debug.h" 17 #include "rtld.h" 18 19 void 20 init_pltgot(Obj_Entry *obj) 21 { 22 if (obj->pltgot != NULL) { 23 obj->pltgot[1] = (Elf_Addr) obj; 24 obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; 25 } 26 } 27 28 int 29 do_copy_relocations(Obj_Entry *dstobj) 30 { 31 const Elf_Rel *rellim; 32 const Elf_Rel *rel; 33 34 assert(dstobj->mainprog); /* COPY relocations are invalid elsewhere */ 35 36 rellim = (const Elf_Rel *) ((caddr_t) dstobj->rel + dstobj->relsize); 37 for (rel = dstobj->rel; rel < rellim; rel++) { 38 if (ELF_R_TYPE(rel->r_info) == R_ARM_COPY) { 39 void *dstaddr; 40 const Elf_Sym *dstsym; 41 const char *name; 42 size_t size; 43 const void *srcaddr; 44 const Elf_Sym *srcsym; 45 const Obj_Entry *srcobj, *defobj; 46 SymLook req; 47 int res; 48 49 dstaddr = (void *) (dstobj->relocbase + rel->r_offset); 50 dstsym = dstobj->symtab + ELF_R_SYM(rel->r_info); 51 name = dstobj->strtab + dstsym->st_name; 52 size = dstsym->st_size; 53 54 symlook_init(&req, name); 55 req.ventry = fetch_ventry(dstobj, 56 ELF_R_SYM(rel->r_info)); 57 for (srcobj = dstobj->next; srcobj != NULL; 58 srcobj = srcobj->next) { 59 res = symlook_obj(&req, srcobj); 60 if (res == 0) { 61 srcsym = req.sym_out; 62 defobj = req.defobj_out; 63 break; 64 } 65 } 66 if (srcobj == NULL) { 67 _rtld_error( 68 "Undefined symbol \"%s\" referenced from COPY relocation in %s", 69 name, dstobj->path); 70 return (-1); 71 } 72 73 srcaddr = (const void *)(defobj->relocbase + 74 srcsym->st_value); 75 memcpy(dstaddr, srcaddr, size); 76 } 77 } 78 return 0; 79 } 80 81 void _rtld_bind_start(void); 82 void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); 83 84 int open(); 85 int _open(); 86 void 87 _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) 88 { 89 const Elf_Rel *rel = 0, *rellim; 90 Elf_Addr relsz = 0; 91 Elf_Addr *where; 92 uint32_t size; 93 94 for (; dynp->d_tag != DT_NULL; dynp++) { 95 switch (dynp->d_tag) { 96 case DT_REL: 97 rel = (const Elf_Rel *)(relocbase + dynp->d_un.d_ptr); 98 break; 99 case DT_RELSZ: 100 relsz = dynp->d_un.d_val; 101 break; 102 } 103 } 104 rellim = (const Elf_Rel *)((caddr_t)rel + relsz); 105 size = (rellim - 1)->r_offset - rel->r_offset; 106 for (; rel < rellim; rel++) { 107 where = (Elf_Addr *)(relocbase + rel->r_offset); 108 109 *where += (Elf_Addr)relocbase; 110 } 111 } 112 /* 113 * It is possible for the compiler to emit relocations for unaligned data. 114 * We handle this situation with these inlines. 115 */ 116 #define RELOC_ALIGNED_P(x) \ 117 (((uintptr_t)(x) & (sizeof(void *) - 1)) == 0) 118 119 static __inline Elf_Addr 120 load_ptr(void *where) 121 { 122 Elf_Addr res; 123 124 memcpy(&res, where, sizeof(res)); 125 126 return (res); 127 } 128 129 static __inline void 130 store_ptr(void *where, Elf_Addr val) 131 { 132 133 memcpy(where, &val, sizeof(val)); 134 } 135 136 static int 137 reloc_nonplt_object(Obj_Entry *obj, const Elf_Rel *rel, SymCache *cache, 138 RtldLockState *lockstate) 139 { 140 Elf_Addr *where; 141 const Elf_Sym *def; 142 const Obj_Entry *defobj; 143 Elf_Addr tmp; 144 unsigned long symnum; 145 146 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 147 symnum = ELF_R_SYM(rel->r_info); 148 149 switch (ELF_R_TYPE(rel->r_info)) { 150 case R_ARM_NONE: 151 break; 152 153 #if 1 /* XXX should not occur */ 154 case R_ARM_PC24: { /* word32 S - P + A */ 155 Elf32_Sword addend; 156 157 /* 158 * Extract addend and sign-extend if needed. 159 */ 160 addend = *where; 161 if (addend & 0x00800000) 162 addend |= 0xff000000; 163 164 def = find_symdef(symnum, obj, &defobj, false, cache, 165 lockstate); 166 if (def == NULL) 167 return -1; 168 tmp = (Elf_Addr)obj->relocbase + def->st_value 169 - (Elf_Addr)where + (addend << 2); 170 if ((tmp & 0xfe000000) != 0xfe000000 && 171 (tmp & 0xfe000000) != 0) { 172 _rtld_error( 173 "%s: R_ARM_PC24 relocation @ %p to %s failed " 174 "(displacement %ld (%#lx) out of range)", 175 obj->path, where, 176 obj->strtab + obj->symtab[symnum].st_name, 177 (long) tmp, (long) tmp); 178 return -1; 179 } 180 tmp >>= 2; 181 *where = (*where & 0xff000000) | (tmp & 0x00ffffff); 182 dbg("PC24 %s in %s --> %p @ %p in %s", 183 obj->strtab + obj->symtab[symnum].st_name, 184 obj->path, (void *)*where, where, defobj->path); 185 break; 186 } 187 #endif 188 189 case R_ARM_ABS32: /* word32 B + S + A */ 190 case R_ARM_GLOB_DAT: /* word32 B + S */ 191 def = find_symdef(symnum, obj, &defobj, false, cache, 192 lockstate); 193 if (def == NULL) 194 return -1; 195 if (__predict_true(RELOC_ALIGNED_P(where))) { 196 tmp = *where + (Elf_Addr)defobj->relocbase + 197 def->st_value; 198 *where = tmp; 199 } else { 200 tmp = load_ptr(where) + 201 (Elf_Addr)defobj->relocbase + 202 def->st_value; 203 store_ptr(where, tmp); 204 } 205 dbg("ABS32/GLOB_DAT %s in %s --> %p @ %p in %s", 206 obj->strtab + obj->symtab[symnum].st_name, 207 obj->path, (void *)tmp, where, defobj->path); 208 break; 209 210 case R_ARM_RELATIVE: /* word32 B + A */ 211 if (__predict_true(RELOC_ALIGNED_P(where))) { 212 tmp = *where + (Elf_Addr)obj->relocbase; 213 *where = tmp; 214 } else { 215 tmp = load_ptr(where) + 216 (Elf_Addr)obj->relocbase; 217 store_ptr(where, tmp); 218 } 219 dbg("RELATIVE in %s --> %p", obj->path, 220 (void *)tmp); 221 break; 222 223 case R_ARM_COPY: 224 /* 225 * These are deferred until all other relocations have 226 * been done. All we do here is make sure that the 227 * COPY relocation is not in a shared library. They 228 * are allowed only in executable files. 229 */ 230 if (!obj->mainprog) { 231 _rtld_error( 232 "%s: Unexpected R_COPY relocation in shared library", 233 obj->path); 234 return -1; 235 } 236 dbg("COPY (avoid in main)"); 237 break; 238 239 case R_ARM_TLS_DTPOFF32: 240 def = find_symdef(symnum, obj, &defobj, false, cache, 241 lockstate); 242 if (def == NULL) 243 return -1; 244 245 tmp = (Elf_Addr)(def->st_value); 246 if (__predict_true(RELOC_ALIGNED_P(where))) 247 *where = tmp; 248 else 249 store_ptr(where, tmp); 250 251 dbg("TLS_DTPOFF32 %s in %s --> %p", 252 obj->strtab + obj->symtab[symnum].st_name, 253 obj->path, (void *)tmp); 254 255 break; 256 case R_ARM_TLS_DTPMOD32: 257 def = find_symdef(symnum, obj, &defobj, false, cache, 258 lockstate); 259 if (def == NULL) 260 return -1; 261 262 tmp = (Elf_Addr)(defobj->tlsindex); 263 if (__predict_true(RELOC_ALIGNED_P(where))) 264 *where = tmp; 265 else 266 store_ptr(where, tmp); 267 268 dbg("TLS_DTPMOD32 %s in %s --> %p", 269 obj->strtab + obj->symtab[symnum].st_name, 270 obj->path, (void *)tmp); 271 272 break; 273 274 case R_ARM_TLS_TPOFF32: 275 def = find_symdef(symnum, obj, &defobj, false, cache, 276 lockstate); 277 if (def == NULL) 278 return -1; 279 280 if (!defobj->tls_done && allocate_tls_offset(obj)) 281 return -1; 282 283 /* XXX: FIXME */ 284 tmp = (Elf_Addr)def->st_value + defobj->tlsoffset + 285 TLS_TCB_SIZE; 286 if (__predict_true(RELOC_ALIGNED_P(where))) 287 *where = tmp; 288 else 289 store_ptr(where, tmp); 290 dbg("TLS_TPOFF32 %s in %s --> %p", 291 obj->strtab + obj->symtab[symnum].st_name, 292 obj->path, (void *)tmp); 293 break; 294 295 296 default: 297 dbg("sym = %lu, type = %lu, offset = %p, " 298 "contents = %p, symbol = %s", 299 symnum, (u_long)ELF_R_TYPE(rel->r_info), 300 (void *)rel->r_offset, (void *)load_ptr(where), 301 obj->strtab + obj->symtab[symnum].st_name); 302 _rtld_error("%s: Unsupported relocation type %ld " 303 "in non-PLT relocations\n", 304 obj->path, (u_long) ELF_R_TYPE(rel->r_info)); 305 return -1; 306 } 307 return 0; 308 } 309 310 /* 311 * * Process non-PLT relocations 312 * */ 313 int 314 reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, RtldLockState *lockstate) 315 { 316 const Elf_Rel *rellim; 317 const Elf_Rel *rel; 318 SymCache *cache; 319 int r = -1; 320 321 /* The relocation for the dynamic loader has already been done. */ 322 if (obj == obj_rtld) 323 return (0); 324 /* 325 * The dynamic loader may be called from a thread, we have 326 * limited amounts of stack available so we cannot use alloca(). 327 */ 328 cache = calloc(obj->nchains, sizeof(SymCache)); 329 /* No need to check for NULL here */ 330 331 rellim = (const Elf_Rel *)((caddr_t)obj->rel + obj->relsize); 332 for (rel = obj->rel; rel < rellim; rel++) { 333 if (reloc_nonplt_object(obj, rel, cache, lockstate) < 0) 334 goto done; 335 } 336 r = 0; 337 done: 338 if (cache != NULL) 339 free(cache); 340 return (r); 341 } 342 343 /* 344 * * Process the PLT relocations. 345 * */ 346 int 347 reloc_plt(Obj_Entry *obj) 348 { 349 const Elf_Rel *rellim; 350 const Elf_Rel *rel; 351 352 rellim = (const Elf_Rel *)((char *)obj->pltrel + 353 obj->pltrelsize); 354 for (rel = obj->pltrel; rel < rellim; rel++) { 355 Elf_Addr *where; 356 357 assert(ELF_R_TYPE(rel->r_info) == R_ARM_JUMP_SLOT); 358 359 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 360 *where += (Elf_Addr )obj->relocbase; 361 } 362 363 return (0); 364 } 365 366 /* 367 * * LD_BIND_NOW was set - force relocation for all jump slots 368 * */ 369 int 370 reloc_jmpslots(Obj_Entry *obj, RtldLockState *lockstate) 371 { 372 const Obj_Entry *defobj; 373 const Elf_Rel *rellim; 374 const Elf_Rel *rel; 375 const Elf_Sym *def; 376 Elf_Addr *where; 377 Elf_Addr target; 378 379 rellim = (const Elf_Rel *)((char *)obj->pltrel + obj->pltrelsize); 380 for (rel = obj->pltrel; rel < rellim; rel++) { 381 assert(ELF_R_TYPE(rel->r_info) == R_ARM_JUMP_SLOT); 382 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 383 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, 384 true, NULL, lockstate); 385 if (def == NULL) { 386 dbg("reloc_jmpslots: sym not found"); 387 return (-1); 388 } 389 390 target = (Elf_Addr)(defobj->relocbase + def->st_value); 391 reloc_jmpslot(where, target, defobj, obj, 392 (const Elf_Rel *) rel); 393 } 394 395 obj->jmpslots_done = true; 396 397 return (0); 398 } 399 400 int 401 reloc_iresolve(Obj_Entry *obj, struct Struct_RtldLockState *lockstate) 402 { 403 404 /* XXX not implemented */ 405 return (0); 406 } 407 408 int 409 reloc_gnu_ifunc(Obj_Entry *obj, struct Struct_RtldLockState *lockstate) 410 { 411 412 /* XXX not implemented */ 413 return (0); 414 } 415 416 Elf_Addr 417 reloc_jmpslot(Elf_Addr *where, Elf_Addr target, const Obj_Entry *defobj, 418 const Obj_Entry *obj, const Elf_Rel *rel) 419 { 420 421 assert(ELF_R_TYPE(rel->r_info) == R_ARM_JUMP_SLOT); 422 423 if (*where != target) 424 *where = target; 425 426 return target; 427 } 428 429 void 430 allocate_initial_tls(Obj_Entry *objs) 431 { 432 void **_tp = (void **)ARM_TP_ADDRESS; 433 434 /* 435 * Fix the size of the static TLS block by using the maximum 436 * offset allocated so far and adding a bit for dynamic modules to 437 * use. 438 */ 439 440 tls_static_space = tls_last_offset + tls_last_size + RTLD_STATIC_TLS_EXTRA; 441 442 (*_tp) = (void *) allocate_tls(objs, NULL, TLS_TCB_SIZE, 8); 443 } 444 445 void * 446 __tls_get_addr(tls_index* ti) 447 { 448 void **_tp = (void **)ARM_TP_ADDRESS; 449 char *p; 450 451 p = tls_get_addr_common((Elf_Addr **)(*_tp), ti->ti_module, ti->ti_offset); 452 453 return (p); 454 } 455