mdreloc.c revision 1.23
1 /* $NetBSD: mdreloc.c,v 1.23 2003/07/24 10:12:30 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 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(Elf_Dyn *dynp, Elf_Addr relocbase) 97 { 98 const Elf_Rela *rela = 0, *relalim; 99 Elf_Addr relasz = 0; 100 Elf_Addr *where; 101 102 for (; dynp->d_tag != DT_NULL; dynp++) { 103 switch (dynp->d_tag) { 104 case DT_RELA: 105 rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr); 106 break; 107 case DT_RELASZ: 108 relasz = dynp->d_un.d_val; 109 break; 110 } 111 } 112 /* 113 * Assume only 64-bit relocations here, which should always 114 * be true for the dynamic linker. 115 */ 116 relalim = (const Elf_Rela *)((caddr_t)rela + relasz); 117 for (; rela < relalim; rela++) { 118 where = (Elf_Addr *)(relocbase + rela->r_offset); 119 *where = (Elf_Addr)(relocbase + rela->r_addend); 120 } 121 } 122 123 int 124 _rtld_relocate_nonplt_objects(const Obj_Entry *obj) 125 { 126 const Elf_Rela *rela; 127 128 for (rela = obj->rela; rela < obj->relalim; rela++) { 129 Elf64_Addr *where64; 130 Elf32_Addr *where32; 131 const Elf_Sym *def; 132 const Obj_Entry *defobj; 133 Elf64_Addr tmp64; 134 Elf32_Addr tmp32; 135 unsigned long symnum; 136 137 where64 = (Elf64_Addr *)(obj->relocbase + rela->r_offset); 138 where32 = (Elf32_Addr *)where64; 139 symnum = ELF_R_SYM(rela->r_info); 140 141 switch (ELF_R_TYPE(rela->r_info)) { 142 case R_TYPE(NONE): 143 break; 144 145 case R_TYPE(32): /* word32 S + A, truncate */ 146 case R_TYPE(32S): /* word32 S + A, signed truncate */ 147 case R_TYPE(GOT32): /* word32 G + A (XXX can we see these?) */ 148 def = _rtld_find_symdef(symnum, obj, &defobj, false); 149 if (def == NULL) 150 return -1; 151 tmp32 = (Elf32_Addr)(u_long)(defobj->relocbase + 152 def->st_value + rela->r_addend); 153 154 if (*where32 != tmp32) 155 *where32 = tmp32; 156 rdbg(("32/32S %s in %s --> %p in %s", 157 obj->strtab + obj->symtab[symnum].st_name, 158 obj->path, (void *)(unsigned long)*where32, 159 defobj->path)); 160 break; 161 case R_TYPE(64): /* word64 S + A */ 162 def = _rtld_find_symdef(symnum, obj, &defobj, false); 163 if (def == NULL) 164 return -1; 165 166 tmp64 = (Elf64_Addr)(defobj->relocbase + def->st_value + 167 rela->r_addend); 168 169 if (*where64 != tmp64) 170 *where64 = tmp64; 171 rdbg(("64 %s in %s --> %p in %s", 172 obj->strtab + obj->symtab[symnum].st_name, 173 obj->path, (void *)*where64, defobj->path)); 174 break; 175 case R_TYPE(PC32): /* word32 S + A - P */ 176 def = _rtld_find_symdef(symnum, obj, &defobj, false); 177 if (def == NULL) 178 return -1; 179 tmp32 = (Elf32_Addr)(u_long)(defobj->relocbase + 180 def->st_value + rela->r_addend - 181 (Elf64_Addr)where64); 182 if (*where32 != tmp32) 183 *where32 = tmp32; 184 rdbg(("PC32 %s in %s --> %p in %s", 185 obj->strtab + obj->symtab[symnum].st_name, 186 obj->path, (void *)(unsigned long)*where32, 187 defobj->path)); 188 break; 189 case R_TYPE(GLOB_DAT): /* word64 S */ 190 def = _rtld_find_symdef(symnum, obj, &defobj, false); 191 if (def == NULL) 192 return -1; 193 194 tmp64 = (Elf64_Addr)(defobj->relocbase + def->st_value); 195 196 if (*where64 != tmp64) 197 *where64 = tmp64; 198 rdbg(("64 %s in %s --> %p in %s", 199 obj->strtab + obj->symtab[symnum].st_name, 200 obj->path, (void *)*where64, defobj->path)); 201 break; 202 case R_TYPE(RELATIVE): /* word64 B + A */ 203 tmp64 = (Elf64_Addr)(obj->relocbase + rela->r_addend); 204 if (*where64 != tmp64) 205 *where64 = tmp64; 206 rdbg(("RELATIVE in %s --> %p", obj->path, 207 (void *)*where64)); 208 break; 209 210 case R_TYPE(COPY): 211 rdbg(("COPY")); 212 break; 213 214 default: 215 rdbg(("sym = %lu, type = %lu, offset = %p, " 216 "addend = %p, contents = %p, symbol = %s", 217 symnum, (u_long)ELF_R_TYPE(rela->r_info), 218 (void *)rela->r_offset, (void *)rela->r_addend, 219 (void *)*where64, 220 obj->strtab + obj->symtab[symnum].st_name)); 221 _rtld_error("%s: Unsupported relocation type %ld " 222 "in non-PLT relocations\n", 223 obj->path, (u_long) ELF_R_TYPE(rela->r_info)); 224 return -1; 225 } 226 } 227 return 0; 228 } 229 230 int 231 _rtld_relocate_plt_lazy(const Obj_Entry *obj) 232 { 233 const Elf_Rela *rela; 234 235 if (!obj->relocbase) 236 return 0; 237 238 for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) { 239 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 240 241 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JUMP_SLOT)); 242 243 /* Just relocate the GOT slots pointing into the PLT */ 244 *where += (Elf_Addr)obj->relocbase; 245 rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where)); 246 } 247 248 return 0; 249 } 250 251 caddr_t 252 _rtld_bind(const Obj_Entry *obj, Elf_Word reloff) 253 { 254 const Elf_Rela *rela = obj->pltrela + reloff; 255 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 256 Elf_Addr new_value; 257 const Elf_Sym *def; 258 const Obj_Entry *defobj; 259 260 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JUMP_SLOT)); 261 262 def = _rtld_find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, true); 263 if (def == NULL) 264 _rtld_die(); 265 266 new_value = (Elf_Addr)(defobj->relocbase + def->st_value + 267 rela->r_addend); 268 rdbg(("bind now/fixup in %s --> old=%p new=%p", 269 defobj->strtab + def->st_name, (void *)*where, (void *)new_value)); 270 if (*where != new_value) 271 *where = new_value; 272 273 return (caddr_t)(new_value - rela->r_addend); 274 } 275
Indexes created Thu Oct 02 14:10:14 GMT 2025