1 /* $OpenBSD: resolve.c,v 1.9 2002/05/24 04:17:00 deraadt Exp $ */ 2 3 /* 4 * Copyright (c) 1998 Per Fogelstrom, Opsycon AB 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed under OpenBSD by 17 * Per Fogelstrom, Opsycon AB, Sweden. 18 * 4. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 22 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 23 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 25 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 */ 34 35 #define _DYN_LOADER 36 37 #include <sys/types.h> 38 39 #include <nlist.h> 40 #include <link.h> 41 #include "syscall.h" 42 #include "archdep.h" 43 #include "resolve.h" 44 45 elf_object_t *_dl_objects; 46 elf_object_t *_dl_last_object; 47 48 /* 49 * Initialize and add a new dynamic object to the object list. 50 * Perform necessary relocations of pointers. 51 */ 52 53 elf_object_t * 54 _dl_add_object(const char *objname, Elf_Dyn *dynp, const u_long *dl_data, 55 const int objtype, const long laddr, const long loff) 56 { 57 elf_object_t *object; 58 #if 0 59 _dl_printf("objname [%s], dynp %p, dl_data %p, objtype %x laddr %lx, loff %lx\n", 60 objname, dynp, dl_data, objtype, laddr, loff); 61 #endif 62 63 object = _dl_malloc(sizeof(elf_object_t)); 64 65 object->next = NULL; 66 if (_dl_objects == 0) { /* First object ? */ 67 _dl_last_object = _dl_objects = object; 68 } else { 69 _dl_last_object->next = object; 70 object->prev = _dl_last_object; 71 _dl_last_object = object; 72 } 73 74 object->load_dyn = dynp; 75 while (dynp->d_tag != DT_NULL) { 76 if (dynp->d_tag < DT_NUM) { 77 object->Dyn.info[dynp->d_tag] = dynp->d_un.d_val; 78 } else if (dynp->d_tag >= DT_LOPROC && 79 dynp->d_tag < DT_LOPROC + DT_NUM) { 80 object->Dyn.info[dynp->d_tag + DT_NUM - DT_LOPROC] = dynp-> 81 d_un.d_val; 82 } 83 if (dynp->d_tag == DT_TEXTREL) 84 object->dyn.textrel = 1; 85 if (dynp->d_tag == DT_SYMBOLIC) 86 object->dyn.symbolic = 1; 87 if (dynp->d_tag == DT_BIND_NOW) 88 object->dyn.bind_now = 1; 89 dynp++; 90 } 91 92 /* 93 * Now relocate all pointer to dynamic info, but only 94 * the ones which has pointer values. 95 */ 96 if (object->Dyn.info[DT_PLTGOT]) 97 object->Dyn.info[DT_PLTGOT] += loff; 98 if (object->Dyn.info[DT_HASH]) 99 object->Dyn.info[DT_HASH] += loff; 100 if (object->Dyn.info[DT_STRTAB]) 101 object->Dyn.info[DT_STRTAB] += loff; 102 if (object->Dyn.info[DT_SYMTAB]) 103 object->Dyn.info[DT_SYMTAB] += loff; 104 if (object->Dyn.info[DT_RELA]) 105 object->Dyn.info[DT_RELA] += loff; 106 if (object->Dyn.info[DT_SONAME]) 107 object->Dyn.info[DT_SONAME] += loff; 108 if (object->Dyn.info[DT_RPATH]) 109 object->Dyn.info[DT_RPATH] += object->Dyn.info[DT_STRTAB]; 110 if (object->Dyn.info[DT_REL]) 111 object->Dyn.info[DT_REL] += loff; 112 if (object->Dyn.info[DT_INIT]) 113 object->Dyn.info[DT_INIT] += loff; 114 if (object->Dyn.info[DT_FINI]) 115 object->Dyn.info[DT_FINI] += loff; 116 if (object->Dyn.info[DT_JMPREL]) 117 object->Dyn.info[DT_JMPREL] += loff; 118 119 if (object->Dyn.info[DT_HASH] != 0) { 120 Elf_Word *hashtab = (Elf_Word *)object->Dyn.info[DT_HASH]; 121 122 object->nbuckets = hashtab[0]; 123 object->nchains = hashtab[1]; 124 object->buckets = hashtab + 2; 125 object->chains = object->buckets + object->nbuckets; 126 } 127 128 if (dl_data) { 129 object->phdrp = (Elf_Phdr *) dl_data[AUX_phdr]; 130 object->phdrc = dl_data[AUX_phnum]; 131 } 132 object->obj_type = objtype; 133 object->load_addr = laddr; 134 object->load_offs = loff; 135 object->load_name = _dl_strdup(objname); 136 object->refcount = 1; 137 return(object); 138 } 139 140 void 141 _dl_remove_object(elf_object_t *object) 142 { 143 elf_object_t *depobj; 144 145 object->prev->next = object->next; 146 if (object->next) 147 object->next->prev = object->prev; 148 149 if (_dl_last_object == object) 150 _dl_last_object = object->prev; 151 152 if (object->load_name) 153 _dl_free(object->load_name); 154 155 while ((depobj = object->dep_next)) { 156 object->dep_next = object->dep_next->dep_next; 157 _dl_free(depobj); 158 } 159 _dl_free(object); 160 } 161 162 163 elf_object_t * 164 _dl_lookup_object(const char *name) 165 { 166 elf_object_t *object; 167 168 object = _dl_objects; 169 while (object) { 170 if (_dl_strcmp(name, object->load_name) == 0) 171 return(object); 172 object = object->next; 173 } 174 return(0); 175 } 176 177 178 Elf_Addr 179 _dl_find_symbol(const char *name, elf_object_t *startlook, 180 const Elf_Sym **ref, int myself, int warnnotfound) 181 { 182 unsigned long h = 0; 183 const char *p = name; 184 elf_object_t *object; 185 const Elf_Sym *weak_sym = 0; 186 Elf_Addr weak_offs = 0; 187 188 while (*p) { 189 unsigned long g; 190 h = (h << 4) + *p++; 191 if ((g = h & 0xf0000000)) { 192 h ^= g >> 24; 193 } 194 h &= ~g; 195 } 196 197 for (object = startlook; object; object = (myself ? 0 : object->next)) { 198 const Elf_Sym *symt = object->dyn.symtab; 199 const char *strt = object->dyn.strtab; 200 long si; 201 202 for (si = object->buckets[h % object->nbuckets]; 203 si != STN_UNDEF; si = object->chains[si]) { 204 const Elf_Sym *sym = symt + si; 205 206 if (sym->st_value == 0 || 207 sym->st_shndx == SHN_UNDEF) 208 continue; 209 210 if (ELF_ST_TYPE(sym->st_info) != STT_NOTYPE && 211 ELF_ST_TYPE(sym->st_info) != STT_OBJECT && 212 ELF_ST_TYPE(sym->st_info) != STT_FUNC) 213 continue; 214 215 if (sym != *ref && 216 _dl_strcmp(strt + sym->st_name, name)) 217 continue; 218 219 if (ELF_ST_BIND(sym->st_info) == STB_GLOBAL) { 220 *ref = sym; 221 return(object->load_offs); 222 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) { 223 if (!weak_sym) { 224 weak_sym = sym; 225 weak_offs = object->load_offs; 226 } 227 } 228 } 229 } 230 if (warnnotfound) { 231 if (!weak_sym && *ref && 232 ELF_ST_BIND((*ref)->st_info) != STB_WEAK) { 233 _dl_printf("%s: undefined symbol '%s'\n", 234 _dl_progname, name); 235 } 236 } 237 *ref = weak_sym; 238 return(weak_offs); 239 } 240