mdreloc.c revision 1.24
1 /* $NetBSD: mdreloc.c,v 1.24 2005/07/17 05:57:21 skrll Exp $ */ 2 3 /* 4 * Copyright (c) 2001 Wasabi Systems, Inc. 5 * All rights reserved. 6 * 7 * Written by Frank van der Linden for Wasabi Systems, Inc. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed for the NetBSD Project by 20 * Wasabi Systems, Inc. 21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse 22 * or promote products derived from this software without specific prior 23 * written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC 29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 * POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38 /* 39 * Copyright 1996 John D. Polstra. 40 * Copyright 1996 Matt Thomas <matt (at) 3am-software.com> 41 * All rights reserved. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. All advertising materials mentioning features or use of this software 52 * must display the following acknowledgement: 53 * This product includes software developed by John Polstra. 54 * 4. The name of the author may not be used to endorse or promote products 55 * derived from this software without specific prior written permission. 56 * 57 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 58 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 59 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 60 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 61 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 62 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 63 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 64 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 65 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 66 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 67 */ 68 69 #include <sys/types.h> 70 #include <sys/mman.h> 71 #include <err.h> 72 #include <errno.h> 73 #include <fcntl.h> 74 #include <stdarg.h> 75 #include <stdio.h> 76 #include <stdlib.h> 77 #include <string.h> 78 #include <unistd.h> 79 #include <elf.h> 80 81 #include "debug.h" 82 #include "rtld.h" 83 84 void _rtld_bind_start(void); 85 void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); 86 caddr_t _rtld_bind(const Obj_Entry *, Elf_Word); 87 static inline int _rtld_relocate_plt_object(const Obj_Entry *obj, 88 const Elf_Rela *rela, Elf_Addr *tp); 89 90 void 91 _rtld_setup_pltgot(const Obj_Entry *obj) 92 { 93 obj->pltgot[1] = (Elf_Addr) obj; 94 obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; 95 } 96 97 void 98 _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) 99 { 100 const Elf_Rela *rela = 0, *relalim; 101 Elf_Addr relasz = 0; 102 Elf_Addr *where; 103 104 for (; dynp->d_tag != DT_NULL; dynp++) { 105 switch (dynp->d_tag) { 106 case DT_RELA: 107 rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr); 108 break; 109 case DT_RELASZ: 110 relasz = dynp->d_un.d_val; 111 break; 112 } 113 } 114 /* 115 * Assume only 64-bit relocations here, which should always 116 * be true for the dynamic linker. 117 */ 118 relalim = (const Elf_Rela *)((caddr_t)rela + relasz); 119 for (; rela < relalim; rela++) { 120 where = (Elf_Addr *)(relocbase + rela->r_offset); 121 *where = (Elf_Addr)(relocbase + rela->r_addend); 122 } 123 } 124 125 int 126 _rtld_relocate_nonplt_objects(const Obj_Entry *obj) 127 { 128 const Elf_Rela *rela; 129 130 for (rela = obj->rela; rela < obj->relalim; rela++) { 131 Elf64_Addr *where64; 132 Elf32_Addr *where32; 133 const Elf_Sym *def; 134 const Obj_Entry *defobj; 135 Elf64_Addr tmp64; 136 Elf32_Addr tmp32; 137 unsigned long symnum; 138 139 where64 = (Elf64_Addr *)(obj->relocbase + rela->r_offset); 140 where32 = (Elf32_Addr *)where64; 141 symnum = ELF_R_SYM(rela->r_info); 142 143 switch (ELF_R_TYPE(rela->r_info)) { 144 case R_TYPE(NONE): 145 break; 146 147 case R_TYPE(32): /* word32 S + A, truncate */ 148 case R_TYPE(32S): /* word32 S + A, signed truncate */ 149 case R_TYPE(GOT32): /* word32 G + A (XXX can we see these?) */ 150 def = _rtld_find_symdef(symnum, obj, &defobj, false); 151 if (def == NULL) 152 return -1; 153 tmp32 = (Elf32_Addr)(u_long)(defobj->relocbase + 154 def->st_value + rela->r_addend); 155 156 if (*where32 != tmp32) 157 *where32 = tmp32; 158 rdbg(("32/32S %s in %s --> %p in %s", 159 obj->strtab + obj->symtab[symnum].st_name, 160 obj->path, (void *)(unsigned long)*where32, 161 defobj->path)); 162 break; 163 case R_TYPE(64): /* word64 S + A */ 164 def = _rtld_find_symdef(symnum, obj, &defobj, false); 165 if (def == NULL) 166 return -1; 167 168 tmp64 = (Elf64_Addr)(defobj->relocbase + def->st_value + 169 rela->r_addend); 170 171 if (*where64 != tmp64) 172 *where64 = tmp64; 173 rdbg(("64 %s in %s --> %p in %s", 174 obj->strtab + obj->symtab[symnum].st_name, 175 obj->path, (void *)*where64, defobj->path)); 176 break; 177 case R_TYPE(PC32): /* word32 S + A - P */ 178 def = _rtld_find_symdef(symnum, obj, &defobj, false); 179 if (def == NULL) 180 return -1; 181 tmp32 = (Elf32_Addr)(u_long)(defobj->relocbase + 182 def->st_value + rela->r_addend - 183 (Elf64_Addr)where64); 184 if (*where32 != tmp32) 185 *where32 = tmp32; 186 rdbg(("PC32 %s in %s --> %p in %s", 187 obj->strtab + obj->symtab[symnum].st_name, 188 obj->path, (void *)(unsigned long)*where32, 189 defobj->path)); 190 break; 191 case R_TYPE(GLOB_DAT): /* word64 S */ 192 def = _rtld_find_symdef(symnum, obj, &defobj, false); 193 if (def == NULL) 194 return -1; 195 196 tmp64 = (Elf64_Addr)(defobj->relocbase + def->st_value); 197 198 if (*where64 != tmp64) 199 *where64 = tmp64; 200 rdbg(("64 %s in %s --> %p in %s", 201 obj->strtab + obj->symtab[symnum].st_name, 202 obj->path, (void *)*where64, defobj->path)); 203 break; 204 case R_TYPE(RELATIVE): /* word64 B + A */ 205 tmp64 = (Elf64_Addr)(obj->relocbase + rela->r_addend); 206 if (*where64 != tmp64) 207 *where64 = tmp64; 208 rdbg(("RELATIVE in %s --> %p", obj->path, 209 (void *)*where64)); 210 break; 211 212 case R_TYPE(COPY): 213 rdbg(("COPY")); 214 break; 215 216 default: 217 rdbg(("sym = %lu, type = %lu, offset = %p, " 218 "addend = %p, contents = %p, symbol = %s", 219 symnum, (u_long)ELF_R_TYPE(rela->r_info), 220 (void *)rela->r_offset, (void *)rela->r_addend, 221 (void *)*where64, 222 obj->strtab + obj->symtab[symnum].st_name)); 223 _rtld_error("%s: Unsupported relocation type %ld " 224 "in non-PLT relocations\n", 225 obj->path, (u_long) ELF_R_TYPE(rela->r_info)); 226 return -1; 227 } 228 } 229 return 0; 230 } 231 232 int 233 _rtld_relocate_plt_lazy(const Obj_Entry *obj) 234 { 235 const Elf_Rela *rela; 236 237 if (!obj->relocbase) 238 return 0; 239 240 for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) { 241 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 242 243 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JUMP_SLOT)); 244 245 /* Just relocate the GOT slots pointing into the PLT */ 246 *where += (Elf_Addr)obj->relocbase; 247 rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where)); 248 } 249 250 return 0; 251 } 252 253 static inline int 254 _rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, Elf_Addr *tp) 255 { 256 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 257 Elf_Addr new_value; 258 const Elf_Sym *def; 259 const Obj_Entry *defobj; 260 261 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JUMP_SLOT)); 262 263 def = _rtld_find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, true); 264 if (def == NULL) 265 return -1; 266 267 new_value = (Elf_Addr)(defobj->relocbase + def->st_value + 268 rela->r_addend); 269 rdbg(("bind now/fixup in %s --> old=%p new=%p", 270 defobj->strtab + def->st_name, (void *)*where, (void *)new_value)); 271 if (*where != new_value) 272 *where = new_value; 273 274 if (tp) 275 *tp = new_value - rela->r_addend; 276 277 return 0; 278 } 279 280 caddr_t 281 _rtld_bind(const Obj_Entry *obj, Elf_Word reloff) 282 { 283 const Elf_Rela *rela = obj->pltrela + reloff; 284 Elf_Addr new_value; 285 int err; 286 287 err = _rtld_relocate_plt_object(obj, rela, &new_value); 288 if (err) 289 _rtld_die(); 290 291 return (caddr_t)new_value; 292 } 293 294 int 295 _rtld_relocate_plt_objects(const Obj_Entry *obj) 296 { 297 const Elf_Rela *rela; 298 299 for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) 300 if (_rtld_relocate_plt_object(obj, rela, NULL) < 0) 301 return -1; 302 303 return 0; 304 } 305
Indexes created Thu Oct 02 10:09:58 GMT 2025