1 /* $NetBSD: mdreloc.c,v 1.22 2002/11/24 18:19:23 fvdl 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@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 __P((const Obj_Entry *, Elf_Word)); 87 88 void 89 _rtld_setup_pltgot(const Obj_Entry *obj) 90 { 91 obj->pltgot[1] = (Elf_Addr) obj; 92 obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; 93 } 94 95 void 96 _rtld_relocate_nonplt_self(dynp, relocbase) 97 Elf_Dyn *dynp; 98 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(obj) 127 const Obj_Entry *obj; 128 { 129 const Elf_Rela *rela; 130 131 for (rela = obj->rela; rela < obj->relalim; rela++) { 132 Elf64_Addr *where64; 133 Elf32_Addr *where32; 134 const Elf_Sym *def; 135 const Obj_Entry *defobj; 136 Elf64_Addr tmp64; 137 Elf32_Addr tmp32; 138 unsigned long symnum; 139 140 where64 = (Elf64_Addr *)(obj->relocbase + rela->r_offset); 141 where32 = (Elf32_Addr *)where64; 142 symnum = ELF_R_SYM(rela->r_info); 143 144 switch (ELF_R_TYPE(rela->r_info)) { 145 case R_TYPE(NONE): 146 break; 147 148 case R_TYPE(32): /* word32 S + A, truncate */ 149 case R_TYPE(32S): /* word32 S + A, signed truncate */ 150 case R_TYPE(GOT32): /* word32 G + A (XXX can we see these?) */ 151 def = _rtld_find_symdef(symnum, obj, &defobj, false); 152 if (def == NULL) 153 return -1; 154 tmp32 = (Elf32_Addr)(u_long)(defobj->relocbase + 155 def->st_value + rela->r_addend); 156 157 if (*where32 != tmp32) 158 *where32 = tmp32; 159 rdbg(("32/32S %s in %s --> %p in %s", 160 obj->strtab + obj->symtab[symnum].st_name, 161 obj->path, (void *)(unsigned long)*where32, 162 defobj->path)); 163 break; 164 case R_TYPE(64): /* word64 S + A */ 165 def = _rtld_find_symdef(symnum, obj, &defobj, false); 166 if (def == NULL) 167 return -1; 168 169 tmp64 = (Elf64_Addr)(defobj->relocbase + def->st_value + 170 rela->r_addend); 171 172 if (*where64 != tmp64) 173 *where64 = tmp64; 174 rdbg(("64 %s in %s --> %p in %s", 175 obj->strtab + obj->symtab[symnum].st_name, 176 obj->path, (void *)*where64, defobj->path)); 177 break; 178 case R_TYPE(PC32): /* word32 S + A - P */ 179 def = _rtld_find_symdef(symnum, obj, &defobj, false); 180 if (def == NULL) 181 return -1; 182 tmp32 = (Elf32_Addr)(u_long)(defobj->relocbase + 183 def->st_value + rela->r_addend - 184 (Elf64_Addr)where64); 185 if (*where32 != tmp32) 186 *where32 = tmp32; 187 rdbg(("PC32 %s in %s --> %p in %s", 188 obj->strtab + obj->symtab[symnum].st_name, 189 obj->path, (void *)(unsigned long)*where32, 190 defobj->path)); 191 break; 192 case R_TYPE(GLOB_DAT): /* word64 S */ 193 def = _rtld_find_symdef(symnum, obj, &defobj, false); 194 if (def == NULL) 195 return -1; 196 197 tmp64 = (Elf64_Addr)(defobj->relocbase + def->st_value); 198 199 if (*where64 != tmp64) 200 *where64 = tmp64; 201 rdbg(("64 %s in %s --> %p in %s", 202 obj->strtab + obj->symtab[symnum].st_name, 203 obj->path, (void *)*where64, defobj->path)); 204 break; 205 case R_TYPE(RELATIVE): /* word64 B + A */ 206 tmp64 = (Elf64_Addr)(obj->relocbase + rela->r_addend); 207 if (*where64 != tmp64) 208 *where64 = tmp64; 209 rdbg(("RELATIVE in %s --> %p", obj->path, 210 (void *)*where64)); 211 break; 212 213 case R_TYPE(COPY): 214 rdbg(("COPY")); 215 break; 216 217 default: 218 rdbg(("sym = %lu, type = %lu, offset = %p, " 219 "addend = %p, contents = %p, symbol = %s", 220 symnum, (u_long)ELF_R_TYPE(rela->r_info), 221 (void *)rela->r_offset, (void *)rela->r_addend, 222 (void *)*where64, 223 obj->strtab + obj->symtab[symnum].st_name)); 224 _rtld_error("%s: Unsupported relocation type %ld " 225 "in non-PLT relocations\n", 226 obj->path, (u_long) ELF_R_TYPE(rela->r_info)); 227 return -1; 228 } 229 } 230 return 0; 231 } 232 233 int 234 _rtld_relocate_plt_lazy(obj) 235 const Obj_Entry *obj; 236 { 237 const Elf_Rela *rela; 238 239 if (!obj->relocbase) 240 return 0; 241 242 for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) { 243 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 244 245 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JUMP_SLOT)); 246 247 /* Just relocate the GOT slots pointing into the PLT */ 248 *where += (Elf_Addr)obj->relocbase; 249 rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where)); 250 } 251 252 return 0; 253 } 254 255 caddr_t 256 _rtld_bind(obj, reloff) 257 const Obj_Entry *obj; 258 Elf_Word reloff; 259 { 260 const Elf_Rela *rela = obj->pltrela + reloff; 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 _rtld_die(); 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 return (caddr_t)(new_value - rela->r_addend); 280 } 281