mdreloc.c revision 1.26
1 /* $NetBSD: mdreloc.c,v 1.26 2005/08/20 19:01:17 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/cdefs.h> 70 #ifndef lint 71 __RCSID("$NetBSD: mdreloc.c,v 1.26 2005/08/20 19:01:17 skrll Exp $"); 72 #endif /* not lint */ 73 74 #include <sys/types.h> 75 #include <sys/mman.h> 76 #include <err.h> 77 #include <errno.h> 78 #include <fcntl.h> 79 #include <stdarg.h> 80 #include <stdio.h> 81 #include <stdlib.h> 82 #include <string.h> 83 #include <unistd.h> 84 #include <elf.h> 85 86 #include "debug.h" 87 #include "rtld.h" 88 89 void _rtld_bind_start(void); 90 void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); 91 caddr_t _rtld_bind(const Obj_Entry *, Elf_Word); 92 static inline int _rtld_relocate_plt_object(const Obj_Entry *, 93 const Elf_Rela *, Elf_Addr *); 94 95 void 96 _rtld_setup_pltgot(const Obj_Entry *obj) 97 { 98 obj->pltgot[1] = (Elf_Addr) obj; 99 obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; 100 } 101 102 void 103 _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) 104 { 105 const Elf_Rela *rela = 0, *relalim; 106 Elf_Addr relasz = 0; 107 Elf_Addr *where; 108 109 for (; dynp->d_tag != DT_NULL; dynp++) { 110 switch (dynp->d_tag) { 111 case DT_RELA: 112 rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr); 113 break; 114 case DT_RELASZ: 115 relasz = dynp->d_un.d_val; 116 break; 117 } 118 } 119 /* 120 * Assume only 64-bit relocations here, which should always 121 * be true for the dynamic linker. 122 */ 123 relalim = (const Elf_Rela *)((caddr_t)rela + relasz); 124 for (; rela < relalim; rela++) { 125 where = (Elf_Addr *)(relocbase + rela->r_offset); 126 *where = (Elf_Addr)(relocbase + rela->r_addend); 127 } 128 } 129 130 int 131 _rtld_relocate_nonplt_objects(const Obj_Entry *obj) 132 { 133 const Elf_Rela *rela; 134 135 for (rela = obj->rela; rela < obj->relalim; rela++) { 136 Elf64_Addr *where64; 137 Elf32_Addr *where32; 138 const Elf_Sym *def; 139 const Obj_Entry *defobj; 140 Elf64_Addr tmp64; 141 Elf32_Addr tmp32; 142 unsigned long symnum; 143 144 where64 = (Elf64_Addr *)(obj->relocbase + rela->r_offset); 145 where32 = (Elf32_Addr *)where64; 146 symnum = ELF_R_SYM(rela->r_info); 147 148 switch (ELF_R_TYPE(rela->r_info)) { 149 case R_TYPE(NONE): 150 break; 151 152 case R_TYPE(32): /* word32 S + A, truncate */ 153 case R_TYPE(32S): /* word32 S + A, signed truncate */ 154 case R_TYPE(GOT32): /* word32 G + A (XXX can we see these?) */ 155 def = _rtld_find_symdef(symnum, obj, &defobj, false); 156 if (def == NULL) 157 return -1; 158 tmp32 = (Elf32_Addr)(u_long)(defobj->relocbase + 159 def->st_value + rela->r_addend); 160 161 if (*where32 != tmp32) 162 *where32 = tmp32; 163 rdbg(("32/32S %s in %s --> %p in %s", 164 obj->strtab + obj->symtab[symnum].st_name, 165 obj->path, (void *)(unsigned long)*where32, 166 defobj->path)); 167 break; 168 case R_TYPE(64): /* word64 S + A */ 169 def = _rtld_find_symdef(symnum, obj, &defobj, false); 170 if (def == NULL) 171 return -1; 172 173 tmp64 = (Elf64_Addr)(defobj->relocbase + def->st_value + 174 rela->r_addend); 175 176 if (*where64 != tmp64) 177 *where64 = tmp64; 178 rdbg(("64 %s in %s --> %p in %s", 179 obj->strtab + obj->symtab[symnum].st_name, 180 obj->path, (void *)*where64, defobj->path)); 181 break; 182 case R_TYPE(PC32): /* word32 S + A - P */ 183 def = _rtld_find_symdef(symnum, obj, &defobj, false); 184 if (def == NULL) 185 return -1; 186 tmp32 = (Elf32_Addr)(u_long)(defobj->relocbase + 187 def->st_value + rela->r_addend - 188 (Elf64_Addr)where64); 189 if (*where32 != tmp32) 190 *where32 = tmp32; 191 rdbg(("PC32 %s in %s --> %p in %s", 192 obj->strtab + obj->symtab[symnum].st_name, 193 obj->path, (void *)(unsigned long)*where32, 194 defobj->path)); 195 break; 196 case R_TYPE(GLOB_DAT): /* word64 S */ 197 def = _rtld_find_symdef(symnum, obj, &defobj, false); 198 if (def == NULL) 199 return -1; 200 201 tmp64 = (Elf64_Addr)(defobj->relocbase + def->st_value); 202 203 if (*where64 != tmp64) 204 *where64 = tmp64; 205 rdbg(("64 %s in %s --> %p in %s", 206 obj->strtab + obj->symtab[symnum].st_name, 207 obj->path, (void *)*where64, defobj->path)); 208 break; 209 case R_TYPE(RELATIVE): /* word64 B + A */ 210 tmp64 = (Elf64_Addr)(obj->relocbase + rela->r_addend); 211 if (*where64 != tmp64) 212 *where64 = tmp64; 213 rdbg(("RELATIVE in %s --> %p", obj->path, 214 (void *)*where64)); 215 break; 216 217 case R_TYPE(COPY): 218 rdbg(("COPY")); 219 break; 220 221 default: 222 rdbg(("sym = %lu, type = %lu, offset = %p, " 223 "addend = %p, contents = %p, symbol = %s", 224 symnum, (u_long)ELF_R_TYPE(rela->r_info), 225 (void *)rela->r_offset, (void *)rela->r_addend, 226 (void *)*where64, 227 obj->strtab + obj->symtab[symnum].st_name)); 228 _rtld_error("%s: Unsupported relocation type %ld " 229 "in non-PLT relocations\n", 230 obj->path, (u_long) ELF_R_TYPE(rela->r_info)); 231 return -1; 232 } 233 } 234 return 0; 235 } 236 237 int 238 _rtld_relocate_plt_lazy(const Obj_Entry *obj) 239 { 240 const Elf_Rela *rela; 241 242 if (!obj->relocbase) 243 return 0; 244 245 for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) { 246 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 247 248 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JUMP_SLOT)); 249 250 /* Just relocate the GOT slots pointing into the PLT */ 251 *where += (Elf_Addr)obj->relocbase; 252 rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where)); 253 } 254 255 return 0; 256 } 257 258 static inline int 259 _rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, Elf_Addr *tp) 260 { 261 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 262 Elf_Addr new_value; 263 const Elf_Sym *def; 264 const Obj_Entry *defobj; 265 266 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JUMP_SLOT)); 267 268 def = _rtld_find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, true); 269 if (def == NULL) 270 return -1; 271 272 new_value = (Elf_Addr)(defobj->relocbase + def->st_value + 273 rela->r_addend); 274 rdbg(("bind now/fixup in %s --> old=%p new=%p", 275 defobj->strtab + def->st_name, (void *)*where, (void *)new_value)); 276 if (*where != new_value) 277 *where = new_value; 278 279 if (tp) 280 *tp = new_value - rela->r_addend; 281 282 return 0; 283 } 284 285 caddr_t 286 _rtld_bind(const Obj_Entry *obj, Elf_Word reloff) 287 { 288 const Elf_Rela *rela = obj->pltrela + reloff; 289 Elf_Addr new_value; 290 int err; 291 292 err = _rtld_relocate_plt_object(obj, rela, &new_value); 293 if (err) 294 _rtld_die(); 295 296 return (caddr_t)new_value; 297 } 298 299 int 300 _rtld_relocate_plt_objects(const Obj_Entry *obj) 301 { 302 const Elf_Rela *rela; 303 304 for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) 305 if (_rtld_relocate_plt_object(obj, rela, NULL) < 0) 306 return -1; 307 308 return 0; 309 } 310
Indexes created Thu Oct 02 10:09:58 GMT 2025