mdreloc.c revision 1.6
1 /* $NetBSD: mdreloc.c,v 1.6 2024/11/30 01:04:05 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2014 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Matt Thomas of 3am Software Foundry. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #ifndef lint 34 __RCSID("$NetBSD: mdreloc.c,v 1.6 2024/11/30 01:04:05 christos Exp $"); 35 #endif /* not lint */ 36 37 #include <stdarg.h> 38 #include <stdio.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include <sys/types.h> 42 #include <machine/cpu.h> 43 44 #include "debug.h" 45 #include "rtld.h" 46 47 #include <machine/lwp_private.h> 48 49 void _rtld_bind_start(void); 50 Elf_Addr _rtld_bind(const Obj_Entry *, Elf_Word); 51 void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); 52 static int _rtld_relocate_plt_object(const Obj_Entry *, 53 const Elf_Rela *, int, Elf_Addr *); 54 55 /* 56 * The OR1k PLT format is simple. 57 */ 58 59 void 60 _rtld_setup_pltgot(const Obj_Entry *obj) 61 { 62 obj->pltgot[1] = (Elf_Addr) obj; 63 obj->pltgot[2] = (Elf_Addr) _rtld_bind_start; 64 65 dbg(("obj %s plt pltgot=%p start=%p obj=%p", 66 obj->path, obj->pltgot, 67 (void *) obj->pltgot[1], (void *) obj->pltgot[2])); 68 } 69 70 void 71 _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) 72 { 73 const Elf_Rela *rela = 0, *relalim; 74 Elf_Addr relasz = 0; 75 Elf_Addr *where; 76 77 for (; dynp->d_tag != DT_NULL; dynp++) { 78 switch (dynp->d_tag) { 79 case DT_RELA: 80 rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr); 81 break; 82 case DT_RELASZ: 83 relasz = dynp->d_un.d_val; 84 break; 85 } 86 } 87 relalim = (const Elf_Rela *)((const uint8_t *)rela + relasz); 88 for (; rela < relalim; rela++) { 89 where = (Elf_Addr *)(relocbase + rela->r_offset); 90 *where = (Elf_Addr)(relocbase + rela->r_addend); 91 } 92 } 93 94 int 95 _rtld_relocate_nonplt_objects(Obj_Entry *obj) 96 { 97 const Elf_Rela *rela; 98 const Elf_Sym *def = NULL; 99 const Obj_Entry *defobj = NULL; 100 unsigned long last_symnum = ULONG_MAX; 101 102 for (rela = obj->rela; rela < obj->relalim; rela++) { 103 Elf_Addr *where; 104 Elf_Addr tmp; 105 unsigned long symnum; 106 107 where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 108 109 switch (ELF_R_TYPE(rela->r_info)) { 110 case R_TYPE(32): /* <address> S + A */ 111 case R_TYPE(GLOB_DAT): /* <address> S + A */ 112 case R_TYPE(TLS_DTPMOD): 113 case R_TYPE(TLS_DTPOFF): 114 case R_TYPE(TLS_TPOFF): 115 symnum = ELF_R_SYM(rela->r_info); 116 if (last_symnum != symnum) { 117 last_symnum = symnum; 118 def = _rtld_find_symdef(symnum, obj, &defobj, 119 false); 120 if (def == NULL) 121 return -1; 122 } 123 break; 124 default: 125 break; 126 } 127 128 switch (ELF_R_TYPE(rela->r_info)) { 129 #if 1 /* XXX Should not be necessary. */ 130 case R_TYPE(JMP_SLOT): 131 #endif 132 case R_TYPE(NONE): 133 break; 134 135 case R_TYPE(32): /* <address> S + A */ 136 case R_TYPE(GLOB_DAT): /* <address> S + A */ 137 tmp = (Elf_Addr)(defobj->relocbase + def->st_value + 138 rela->r_addend); 139 if (*where != tmp) 140 *where = tmp; 141 rdbg(("32/GLOB_DAT %s in %s --> %p in %s", 142 obj->strtab + obj->symtab[symnum].st_name, 143 obj->path, (void *)*where, defobj->path)); 144 break; 145 146 case R_TYPE(RELATIVE): /* <address> B + A */ 147 *where = (Elf_Addr)(obj->relocbase + rela->r_addend); 148 rdbg(("RELATIVE in %s --> %p", obj->path, 149 (void *)*where)); 150 break; 151 152 case R_TYPE(COPY): 153 /* 154 * These are deferred until all other relocations have 155 * been done. All we do here is make sure that the 156 * COPY relocation is not in a shared library. They 157 * are allowed only in executable files. 158 */ 159 if (obj->isdynamic) { 160 _rtld_error( 161 "%s: Unexpected R_COPY relocation in shared library", 162 obj->path); 163 return -1; 164 } 165 rdbg(("COPY (avoid in main)")); 166 break; 167 168 case R_TYPE(TLS_DTPMOD): 169 *where = (Elf_Addr)defobj->tlsindex; 170 rdbg(("DTPMOD32 %s in %s --> %p in %s", 171 obj->strtab + obj->symtab[symnum].st_name, 172 obj->path, (void *)*where, defobj->path)); 173 break; 174 175 case R_TYPE(TLS_DTPOFF): 176 *where = (Elf_Addr)(def->st_value + rela->r_addend 177 - TLS_DTV_OFFSET); 178 rdbg(("DTPOFF %s in %s --> %p in %s", 179 obj->strtab + obj->symtab[symnum].st_name, 180 obj->path, (void *)*where, defobj->path)); 181 break; 182 183 case R_TYPE(TLS_TPOFF): 184 if (!defobj->tls_static && 185 _rtld_tls_offset_allocate(__UNCONST(defobj))) 186 return -1; 187 188 *where = (Elf_Addr)(def->st_value + rela->r_addend 189 + defobj->tlsoffset - TLS_TP_OFFSET); 190 rdbg(("TPREL %s in %s --> %p in %s", 191 obj->strtab + obj->symtab[symnum].st_name, 192 obj->path, (void *)*where, defobj->path)); 193 break; 194 195 default: 196 rdbg(("sym = %lu, type = %lu, offset = %p, " 197 "addend = %p, contents = %p, symbol = %s", 198 (u_long)ELF_R_SYM(rela->r_info), 199 (u_long)ELF_R_TYPE(rela->r_info), 200 (void *)rela->r_offset, (void *)rela->r_addend, 201 (void *)*where, 202 obj->strtab + obj->symtab[symnum].st_name)); 203 _rtld_error("%s: Unsupported relocation type %ld " 204 "in non-PLT relocations", 205 obj->path, (u_long) ELF_R_TYPE(rela->r_info)); 206 return -1; 207 } 208 } 209 return 0; 210 } 211 212 int 213 _rtld_relocate_plt_lazy(Obj_Entry *obj) 214 { 215 const Elf_Rela *rela; 216 int reloff; 217 218 for (rela = obj->pltrela, reloff = 0; 219 rela < obj->pltrelalim; 220 rela++, reloff++) { 221 Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset); 222 223 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT)); 224 225 /* 226 * For now, simply treat then as relative. 227 */ 228 *where += (Elf_Addr)obj->relocbase; 229 } 230 231 return 0; 232 } 233 234 static int 235 _rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, int reloff, Elf_Addr *tp) 236 { 237 Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset); 238 Elf_Addr value; 239 const Elf_Sym *def; 240 const Obj_Entry *defobj; 241 unsigned long info = rela->r_info; 242 243 assert(ELF_R_TYPE(info) == R_TYPE(JMP_SLOT)); 244 245 def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL); 246 if (__predict_false(def == NULL)) 247 return -1; 248 if (__predict_false(def == &_rtld_sym_zero)) 249 return 0; 250 251 value = (Elf_Addr)(defobj->relocbase + def->st_value); 252 rdbg(("bind now/fixup in %s --> new=%p", 253 defobj->strtab + def->st_name, (void *)value)); 254 255 /* 256 * Simply replace the entry in GOT with the 257 * address of the routine. 258 */ 259 assert(where >= (Elf_Word *)obj->pltgot); 260 assert(where < (Elf_Word *)obj->pltgot + (obj->pltrelalim - obj->pltrela)); 261 *where = value; 262 263 if (tp) 264 *tp = value; 265 return 0; 266 } 267 268 Elf_Addr 269 _rtld_bind(const Obj_Entry *obj, Elf_Word reloff) 270 { 271 const Elf_Rela *rela = obj->pltrela + reloff; 272 Elf_Addr new_value; 273 int err; 274 275 new_value = 0; /* XXX gcc */ 276 277 _rtld_shared_enter(); 278 err = _rtld_relocate_plt_object(obj, rela, reloff, &new_value); 279 if (err) 280 _rtld_die(); 281 _rtld_shared_exit(); 282 283 return new_value; 284 } 285 286 int 287 _rtld_relocate_plt_objects(const Obj_Entry *obj) 288 { 289 const Elf_Rela *rela; 290 int reloff; 291 292 for (rela = obj->pltrela, reloff = 0; rela < obj->pltrelalim; rela++, reloff++) { 293 if (_rtld_relocate_plt_object(obj, rela, reloff, NULL) < 0) 294 return -1; 295 } 296 return 0; 297 } 298
Indexes created Thu Oct 02 14:10:14 GMT 2025