1 /* $OpenBSD: resolve.c,v 1.7 2002/03/17 04:46:53 drahn 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; 137 138 return(object); 139 } 140 141 142 void 143 _dl_remove_object(elf_object_t *object) 144 { 145 elf_object_t *depobj; 146 147 object->prev->next = object->next; 148 if(object->next) { 149 object->next->prev = object->prev; 150 } 151 if (_dl_last_object == object) { 152 _dl_last_object = object->prev; 153 } 154 if(object->load_name) { 155 _dl_free(object->load_name); 156 } 157 while((depobj = object->dep_next)) { 158 object->dep_next = object->dep_next->dep_next; 159 _dl_free(depobj); 160 } 161 _dl_free(object); 162 } 163 164 165 elf_object_t * 166 _dl_lookup_object(const char *name) 167 { 168 elf_object_t *object; 169 170 object = _dl_objects; 171 while(object) { 172 if(_dl_strcmp(name, object->load_name) == 0) { 173 return(object); 174 } 175 object = object->next; 176 } 177 return(0); 178 } 179 180 181 Elf_Addr 182 _dl_find_symbol(const char *name, elf_object_t *startlook, 183 const Elf_Sym **ref, int myself, int warnnotfound) 184 { 185 unsigned long h = 0; 186 const char *p = name; 187 elf_object_t *object; 188 const Elf_Sym *weak_sym = 0; 189 Elf_Addr weak_offs = 0; 190 191 while (*p) { 192 unsigned long g; 193 h = (h << 4) + *p++; 194 if((g = h & 0xf0000000)) { 195 h ^= g >> 24; 196 } 197 h &= ~g; 198 } 199 200 for (object = startlook; object; object = (myself ? 0 : object->next)) { 201 const Elf_Sym *symt; 202 const char *strt; 203 long si; 204 205 symt = object->dyn.symtab; 206 strt = object->dyn.strtab; 207 208 209 for (si = object->buckets[h % object->nbuckets]; 210 si != STN_UNDEF; si = object->chains[si]) { 211 const Elf_Sym *sym = symt + si; 212 213 if (sym->st_value == 0 || 214 sym->st_shndx == SHN_UNDEF) { 215 continue; 216 } 217 218 if (ELF_ST_TYPE(sym->st_info) != STT_NOTYPE && 219 ELF_ST_TYPE(sym->st_info) != STT_OBJECT && 220 ELF_ST_TYPE(sym->st_info) != STT_FUNC) { 221 continue; 222 } 223 224 225 if (sym != *ref && 226 _dl_strcmp(strt + sym->st_name, name)) { 227 continue; 228 } 229 230 if (ELF_ST_BIND(sym->st_info) == STB_GLOBAL) { 231 *ref = sym; 232 return(object->load_offs); 233 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) { 234 if (!weak_sym) { 235 weak_sym = sym; 236 weak_offs = object->load_offs; 237 } 238 } 239 } 240 } 241 if (warnnotfound) { 242 if (!weak_sym && 243 *ref && 244 ELF_ST_BIND((*ref)->st_info) != STB_WEAK) { 245 _dl_printf("%s: undefined symbol '%s'\n", 246 _dl_progname, name); 247 } 248 } 249 *ref = weak_sym; 250 return(weak_offs); 251 } 252 253