1 /* $NetBSD: mdreloc.c,v 1.38 2025/04/16 17:51:01 riastradh Exp $ */ 2 3 /* 4 * Copyright 1996 John D. Polstra. 5 * Copyright 1996 Matt Thomas <matt (at) 3am-software.com> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by John Polstra. 19 * 4. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #include <sys/cdefs.h> 35 #ifndef lint 36 __RCSID("$NetBSD: mdreloc.c,v 1.38 2025/04/16 17:51:01 riastradh Exp $"); 37 #endif /* not lint */ 38 39 /* 40 * SuperH ELF relocations. 41 * 42 * Reference: 43 * 44 * [RM0197] SH-4 generic and C specific application binary interface 45 * https://www.st.com/resource/en/reference_manual/rm0197-sh4-generic-and-c-specific-application-binary-interface-stmicroelectronics.pdf 46 */ 47 48 #include <sys/types.h> 49 #include <sys/tls.h> 50 51 #include "debug.h" 52 #include "rtld.h" 53 54 void _rtld_bind_start(void); 55 void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); 56 caddr_t _rtld_bind(const Obj_Entry *, Elf_Word); 57 static inline int _rtld_relocate_plt_object(const Obj_Entry *, 58 const Elf_Rela *, Elf_Addr *); 59 60 void 61 _rtld_setup_pltgot(const Obj_Entry *obj) 62 { 63 obj->pltgot[1] = (Elf_Addr) obj; 64 obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; 65 } 66 67 void 68 _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) 69 { 70 const Elf_Rela *rela = 0, *relalim; 71 Elf_Addr relasz = 0; 72 Elf_Addr *where; 73 74 for (; dynp->d_tag != DT_NULL; dynp++) { 75 switch (dynp->d_tag) { 76 case DT_RELA: 77 rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr); 78 break; 79 case DT_RELASZ: 80 relasz = dynp->d_un.d_val; 81 break; 82 } 83 } 84 relalim = (const Elf_Rela *)((const uint8_t *)rela + relasz); 85 for (; rela < relalim; rela++) { 86 where = (Elf_Addr *)(relocbase + rela->r_offset); 87 *where = (Elf_Addr)(relocbase + rela->r_addend); 88 } 89 } 90 91 int 92 _rtld_relocate_nonplt_objects(Obj_Entry *obj) 93 { 94 const Elf_Rela *rela; 95 const Elf_Sym *def = NULL; 96 const Obj_Entry *defobj = NULL; 97 unsigned long last_symnum = ULONG_MAX; 98 99 for (rela = obj->rela; rela < obj->relalim; rela++) { 100 Elf_Addr *where; 101 Elf_Addr tmp; 102 unsigned long symnum; 103 104 where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 105 106 switch (ELF_R_TYPE(rela->r_info)) { 107 case R_TYPE(GOT32): 108 case R_TYPE(REL32): 109 case R_TYPE(DIR32): 110 case R_TYPE(GLOB_DAT): 111 case R_TYPE(TLS_DTPOFF32): 112 case R_TYPE(TLS_DTPMOD32): 113 case R_TYPE(TLS_TPOFF32): 114 symnum = ELF_R_SYM(rela->r_info); 115 if (last_symnum != symnum) { 116 last_symnum = symnum; 117 def = _rtld_find_symdef(symnum, obj, &defobj, 118 false); 119 if (def == NULL) 120 return -1; 121 } 122 break; 123 default: 124 break; 125 } 126 127 switch (ELF_R_TYPE(rela->r_info)) { 128 case R_TYPE(NONE): 129 break; 130 131 #if 1 /* XXX should not occur */ 132 case R_TYPE(GOT32): 133 tmp = (Elf_Addr)(defobj->relocbase + def->st_value + 134 rela->r_addend); 135 if (*where != tmp) 136 *where = tmp; 137 rdbg(("GOT32 %s in %s --> %p in %s", 138 obj->strtab + obj->symtab[symnum].st_name, 139 obj->path, (void *)*where, defobj->path)); 140 break; 141 142 case R_TYPE(REL32): 143 tmp = (Elf_Addr)(defobj->relocbase + def->st_value + 144 rela->r_addend) - (Elf_Addr)where; 145 if (*where != tmp) 146 *where = tmp; 147 rdbg(("PC32 %s in %s --> %p in %s", 148 obj->strtab + obj->symtab[symnum].st_name, 149 obj->path, (void *)*where, defobj->path)); 150 break; 151 #endif 152 153 case R_TYPE(DIR32): 154 tmp = (Elf_Addr)(defobj->relocbase + def->st_value + 155 rela->r_addend); 156 if (*where != tmp) 157 *where = tmp; 158 rdbg(("32 %s in %s --> %p in %s", 159 obj->strtab + obj->symtab[symnum].st_name, 160 obj->path, (void *)*where, defobj->path)); 161 break; 162 163 case R_TYPE(GLOB_DAT): 164 tmp = (Elf_Addr)(defobj->relocbase + def->st_value) + 165 rela->r_addend; 166 if (*where != tmp) 167 *where = tmp; 168 rdbg(("GLOB_DAT %s in %s --> %p in %s", 169 obj->strtab + obj->symtab[symnum].st_name, 170 obj->path, (void *)*where, defobj->path)); 171 break; 172 173 case R_TYPE(RELATIVE): 174 if (rela->r_addend) 175 *where = (Elf_Addr)obj->relocbase + rela->r_addend; 176 else 177 *where += (Elf_Addr)obj->relocbase; 178 rdbg(("RELATIVE in %s --> %p", obj->path, 179 (void *)*where)); 180 break; 181 182 case R_TYPE(COPY): 183 /* 184 * These are deferred until all other relocations have 185 * been done. All we do here is make sure that the 186 * COPY relocation is not in a shared library. They 187 * are allowed only in executable files. 188 */ 189 if (obj->isdynamic) { 190 _rtld_error( 191 "%s: Unexpected R_COPY relocation in shared library", 192 obj->path); 193 return -1; 194 } 195 rdbg(("COPY (avoid in main)")); 196 break; 197 198 case R_TYPE(TLS_DTPOFF32): 199 *where = (Elf_Addr)(def->st_value); 200 201 rdbg(("TLS_DTPOFF32 %s in %s --> %p", 202 obj->strtab + obj->symtab[symnum].st_name, 203 obj->path, (void *)*where)); 204 205 break; 206 case R_TYPE(TLS_DTPMOD32): 207 *where = (Elf_Addr)(defobj->tlsindex); 208 209 rdbg(("TLS_DTPMOD32 %s in %s --> %p", 210 obj->strtab + obj->symtab[symnum].st_name, 211 obj->path, (void *)*where)); 212 213 break; 214 215 case R_TYPE(TLS_TPOFF32): 216 if (!defobj->tls_static && 217 _rtld_tls_offset_allocate(__UNCONST(defobj))) 218 return -1; 219 220 *where = (Elf_Addr)def->st_value + 221 rela->r_addend + defobj->tlsoffset + 222 sizeof(struct tls_tcb); 223 224 rdbg(("TLS_TPOFF32 %s in %s --> %p", 225 obj->strtab + obj->symtab[symnum].st_name, 226 obj->path, (void *)*where)); 227 break; 228 229 default: 230 rdbg(("sym = %lu, type = %lu, offset = %p, " 231 "addend = %p, contents = %p, symbol = %s", 232 (u_long)ELF_R_SYM(rela->r_info), 233 (u_long)ELF_R_TYPE(rela->r_info), 234 (void *)rela->r_offset, (void *)rela->r_addend, 235 (void *)*where, 236 obj->strtab + obj->symtab[symnum].st_name)); 237 _rtld_error("%s: Unsupported relocation type %ld " 238 "in non-PLT relocations", 239 obj->path, (u_long) ELF_R_TYPE(rela->r_info)); 240 return -1; 241 } 242 } 243 return 0; 244 } 245 246 int 247 _rtld_relocate_plt_lazy(Obj_Entry *obj) 248 { 249 const Elf_Rela *rela; 250 251 if (!obj->relocbase) 252 return 0; 253 254 for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) { 255 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 256 257 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT)); 258 259 /* Just relocate the GOT slots pointing into the PLT */ 260 *where += (Elf_Addr)obj->relocbase; 261 rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where)); 262 } 263 264 return 0; 265 } 266 267 caddr_t 268 _rtld_bind(const Obj_Entry *obj, Elf_Word reloff) 269 { 270 const Elf_Rela *rela = (const Elf_Rela *)((const uint8_t *)obj->pltrela + reloff); 271 Elf_Addr new_value; 272 int err; 273 274 new_value = 0; /* XXX gcc */ 275 276 _rtld_shared_enter(); 277 err = _rtld_relocate_plt_object(obj, rela, &new_value); 278 if (err) 279 _rtld_die(); 280 _rtld_shared_exit(); 281 282 return (caddr_t)new_value; 283 } 284 285 int 286 _rtld_relocate_plt_objects(const Obj_Entry *obj) 287 { 288 const Elf_Rela *rela = obj->pltrela; 289 290 for (; rela < obj->pltrelalim; rela++) 291 if (_rtld_relocate_plt_object(obj, rela, NULL) < 0) 292 return -1; 293 294 return 0; 295 } 296 297 static inline int 298 _rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, Elf_Addr *tp) 299 { 300 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 301 Elf_Addr new_value; 302 const Elf_Sym *def; 303 const Obj_Entry *defobj; 304 unsigned long info = rela->r_info; 305 306 assert(ELF_R_TYPE(info) == R_TYPE(JMP_SLOT)); 307 308 def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL); 309 if (__predict_false(def == NULL)) 310 return -1; 311 if (__predict_false(def == &_rtld_sym_zero)) 312 return 0; 313 314 if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) { 315 if (tp == NULL) 316 return 0; 317 new_value = _rtld_resolve_ifunc(defobj, def); 318 } else { 319 new_value = (Elf_Addr)(defobj->relocbase + def->st_value); 320 } 321 rdbg(("bind now/fixup in %s --> old=%p new=%p", 322 defobj->strtab + def->st_name, (void *)*where, (void *)new_value)); 323 if (*where != new_value) 324 *where = new_value; 325 326 if (tp) 327 *tp = new_value; 328 329 return 0; 330 } 331
Indexes created Thu Sep 25 02:09:54 GMT 2025