1 /* $OpenBSD: resolve.c,v 1.4 2001/06/08 06:46:59 art 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 void * _dl_malloc(int); 49 50 /* 51 * Initialize and add a new dynamic object to the object list. 52 * Perform necessary relocations of pointers. 53 */ 54 55 elf_object_t * 56 _dl_add_object(const char *objname, Elf_Dyn *dynp, const u_long *dl_data, 57 const int objtype, const long laddr, const long loff) 58 { 59 elf_object_t *object; 60 #if 0 61 _dl_printf("objname [%s], dynp %p, dl_data %p, objtype %x laddr %lx, loff %lx\n", 62 objname, dynp, dl_data, objtype, laddr, loff); 63 #endif 64 65 object = _dl_malloc(sizeof(elf_object_t)); 66 67 if (_dl_objects == 0) { /* First object ? */ 68 _dl_last_object = _dl_objects = object; 69 } else { 70 _dl_last_object->next = object; 71 object->prev = _dl_last_object; 72 _dl_last_object = object; 73 } 74 75 object->load_dyn = dynp; 76 while (dynp->d_tag != DT_NULL) { 77 if (dynp->d_tag < DT_NUM) { 78 object->Dyn.info[dynp->d_tag] = dynp->d_un.d_val; 79 } else if (dynp->d_tag >= DT_LOPROC && 80 dynp->d_tag < DT_LOPROC + DT_NUM) { 81 object->Dyn.info[dynp->d_tag + DT_NUM - DT_LOPROC] = dynp-> 82 d_un.d_val; 83 } 84 if (dynp->d_tag == DT_TEXTREL) 85 object->dyn.textrel = 1; 86 if (dynp->d_tag == DT_SYMBOLIC) 87 object->dyn.symbolic = 1; 88 if (dynp->d_tag == DT_BIND_NOW) 89 object->dyn.bind_now = 1; 90 dynp++; 91 } 92 93 /* 94 * Now relocate all pointer to dynamic info, but only 95 * the ones which has pointer values. 96 */ 97 if(object->Dyn.info[DT_PLTGOT]) 98 object->Dyn.info[DT_PLTGOT] += loff; 99 if(object->Dyn.info[DT_HASH]) 100 object->Dyn.info[DT_HASH] += loff; 101 if(object->Dyn.info[DT_STRTAB]) 102 object->Dyn.info[DT_STRTAB] += loff; 103 if(object->Dyn.info[DT_SYMTAB]) 104 object->Dyn.info[DT_SYMTAB] += loff; 105 if(object->Dyn.info[DT_RELA]) 106 object->Dyn.info[DT_RELA] += loff; 107 if(object->Dyn.info[DT_SONAME]) 108 object->Dyn.info[DT_SONAME] += loff; 109 if(object->Dyn.info[DT_RPATH]) 110 object->Dyn.info[DT_RPATH] += object->Dyn.info[DT_STRTAB]; 111 if(object->Dyn.info[DT_REL]) 112 object->Dyn.info[DT_REL] += loff; 113 if(object->Dyn.info[DT_INIT]) 114 object->Dyn.info[DT_INIT] += loff; 115 if(object->Dyn.info[DT_FINI]) 116 object->Dyn.info[DT_FINI] += loff; 117 if(object->Dyn.info[DT_JMPREL]) 118 object->Dyn.info[DT_JMPREL] += loff; 119 120 object->buckets = object->dyn.hash; 121 if(object->buckets != 0) { 122 object->nbuckets = *object->buckets++; 123 object->nchains = *object->buckets++; 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 = (char *)_dl_malloc(_dl_strlen(objname) + 1); 135 _dl_strcpy(object->load_name, 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(object->load_name) { 152 _dl_free(object->load_name); 153 } 154 while((depobj = object->dep_next)) { 155 object->dep_next = object->dep_next->dep_next; 156 _dl_free(depobj); 157 } 158 _dl_free(object); 159 } 160 161 162 elf_object_t * 163 _dl_lookup_object(const char *name) 164 { 165 elf_object_t *object; 166 167 object = _dl_objects; 168 while(object) { 169 if(_dl_strcmp(name, object->load_name) == 0) { 170 return(object); 171 } 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; 199 const char *strt; 200 u_int32_t si; 201 202 symt = object->dyn.symtab; 203 strt = object->dyn.strtab; 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 if(sym != *ref && _dl_strcmp(strt+sym->st_name, name)) { 221 continue; 222 } 223 224 if(ELF_ST_BIND(sym->st_info) == STB_GLOBAL) { 225 *ref = sym; 226 return(object->load_offs); 227 } 228 else if(ELF_ST_BIND(sym->st_info) == STB_WEAK) { 229 if(!weak_sym) { 230 weak_sym = sym; 231 weak_offs = object->load_offs; 232 } 233 } 234 } 235 } 236 if (warnnotfound) { 237 if(!weak_sym && 238 *ref && ELF_ST_BIND((*ref)->st_info) != STB_WEAK) 239 { 240 _dl_printf("%s: undefined symbol '%s'\n", 241 _dl_progname, name); 242 } 243 } 244 *ref = weak_sym; 245 return(weak_offs); 246 } 247 248