1 /* $OpenBSD: resolve.c,v 1.6 2002/02/21 23:17:53 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 if (_dl_objects == 0) { /* First object ? */ 66 _dl_last_object = _dl_objects = object; 67 } else { 68 _dl_last_object->next = object; 69 object->prev = _dl_last_object; 70 _dl_last_object = object; 71 } 72 73 object->load_dyn = dynp; 74 while (dynp->d_tag != DT_NULL) { 75 if (dynp->d_tag < DT_NUM) { 76 object->Dyn.info[dynp->d_tag] = dynp->d_un.d_val; 77 } else if (dynp->d_tag >= DT_LOPROC && 78 dynp->d_tag < DT_LOPROC + DT_NUM) { 79 object->Dyn.info[dynp->d_tag + DT_NUM - DT_LOPROC] = dynp-> 80 d_un.d_val; 81 } 82 if (dynp->d_tag == DT_TEXTREL) 83 object->dyn.textrel = 1; 84 if (dynp->d_tag == DT_SYMBOLIC) 85 object->dyn.symbolic = 1; 86 if (dynp->d_tag == DT_BIND_NOW) 87 object->dyn.bind_now = 1; 88 dynp++; 89 } 90 91 /* 92 * Now relocate all pointer to dynamic info, but only 93 * the ones which has pointer values. 94 */ 95 if(object->Dyn.info[DT_PLTGOT]) 96 object->Dyn.info[DT_PLTGOT] += loff; 97 if(object->Dyn.info[DT_HASH]) 98 object->Dyn.info[DT_HASH] += loff; 99 if(object->Dyn.info[DT_STRTAB]) 100 object->Dyn.info[DT_STRTAB] += loff; 101 if(object->Dyn.info[DT_SYMTAB]) 102 object->Dyn.info[DT_SYMTAB] += loff; 103 if(object->Dyn.info[DT_RELA]) 104 object->Dyn.info[DT_RELA] += loff; 105 if(object->Dyn.info[DT_SONAME]) 106 object->Dyn.info[DT_SONAME] += loff; 107 if(object->Dyn.info[DT_RPATH]) 108 object->Dyn.info[DT_RPATH] += object->Dyn.info[DT_STRTAB]; 109 if(object->Dyn.info[DT_REL]) 110 object->Dyn.info[DT_REL] += loff; 111 if(object->Dyn.info[DT_INIT]) 112 object->Dyn.info[DT_INIT] += loff; 113 if(object->Dyn.info[DT_FINI]) 114 object->Dyn.info[DT_FINI] += loff; 115 if(object->Dyn.info[DT_JMPREL]) 116 object->Dyn.info[DT_JMPREL] += loff; 117 118 if (object->Dyn.info[DT_HASH] != 0) { 119 Elf_Word *hashtab = (Elf_Word *)object->Dyn.info[DT_HASH]; 120 121 object->nbuckets = hashtab[0]; 122 object->nchains = hashtab[1]; 123 object->buckets = hashtab + 2; 124 object->chains = object->buckets + object->nbuckets; 125 } 126 127 if (dl_data) { 128 object->phdrp = (Elf_Phdr *) dl_data[AUX_phdr]; 129 object->phdrc = dl_data[AUX_phnum]; 130 } 131 object->obj_type = objtype; 132 object->load_addr = laddr; 133 object->load_offs = loff; 134 object->load_name = _dl_strdup(objname); 135 object->refcount = 1; 136 137 return(object); 138 } 139 140 141 void 142 _dl_remove_object(elf_object_t *object) 143 { 144 elf_object_t *depobj; 145 146 object->prev->next = object->next; 147 if(object->next) { 148 object->next->prev = object->prev; 149 } 150 if(object->load_name) { 151 _dl_free(object->load_name); 152 } 153 while((depobj = object->dep_next)) { 154 object->dep_next = object->dep_next->dep_next; 155 _dl_free(depobj); 156 } 157 _dl_free(object); 158 } 159 160 161 elf_object_t * 162 _dl_lookup_object(const char *name) 163 { 164 elf_object_t *object; 165 166 object = _dl_objects; 167 while(object) { 168 if(_dl_strcmp(name, object->load_name) == 0) { 169 return(object); 170 } 171 object = object->next; 172 } 173 return(0); 174 } 175 176 177 Elf_Addr 178 _dl_find_symbol(const char *name, elf_object_t *startlook, 179 const Elf_Sym **ref, int myself, int warnnotfound) 180 { 181 unsigned long h = 0; 182 const char *p = name; 183 elf_object_t *object; 184 const Elf_Sym *weak_sym = 0; 185 Elf_Addr weak_offs = 0; 186 187 while (*p) { 188 unsigned long g; 189 h = (h << 4) + *p++; 190 if((g = h & 0xf0000000)) { 191 h ^= g >> 24; 192 } 193 h &= ~g; 194 } 195 196 for (object = startlook; object; object = (myself ? 0 : object->next)) { 197 const Elf_Sym *symt; 198 const char *strt; 199 long si; 200 201 symt = object->dyn.symtab; 202 strt = object->dyn.strtab; 203 204 205 for (si = object->buckets[h % object->nbuckets]; 206 si != STN_UNDEF; si = object->chains[si]) { 207 const Elf_Sym *sym = symt + si; 208 209 if (sym->st_value == 0 || 210 sym->st_shndx == SHN_UNDEF) { 211 continue; 212 } 213 214 if (ELF_ST_TYPE(sym->st_info) != STT_NOTYPE && 215 ELF_ST_TYPE(sym->st_info) != STT_OBJECT && 216 ELF_ST_TYPE(sym->st_info) != STT_FUNC) { 217 continue; 218 } 219 220 221 if (sym != *ref && 222 _dl_strcmp(strt + sym->st_name, name)) { 223 continue; 224 } 225 226 if (ELF_ST_BIND(sym->st_info) == STB_GLOBAL) { 227 *ref = sym; 228 return(object->load_offs); 229 } else if (ELF_ST_BIND(sym->st_info) == STB_WEAK) { 230 if (!weak_sym) { 231 weak_sym = sym; 232 weak_offs = object->load_offs; 233 } 234 } 235 } 236 } 237 if (warnnotfound) { 238 if (!weak_sym && 239 *ref && 240 ELF_ST_BIND((*ref)->st_info) != STB_WEAK) { 241 _dl_printf("%s: undefined symbol '%s'\n", 242 _dl_progname, name); 243 } 244 } 245 *ref = weak_sym; 246 return(weak_offs); 247 } 248 249