1 /* $OpenBSD: resolve.c,v 1.2 2001/04/02 23:11:21 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 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, 57 const u_long *dl_data, const int objtype, 58 const long laddr, const long loff) 59 { 60 elf_object_t *object; 61 #if 0 62 _dl_printf("objname [%s], dynp %p, dl_data %p, objtype %x laddr %lx, loff %lx\n", 63 objname, dynp, dl_data, objtype, laddr, loff); 64 #endif 65 66 object = (elf_object_t *)_dl_malloc(sizeof(elf_object_t)); 67 68 if(_dl_objects == 0) { /* First object ? */ 69 _dl_last_object = _dl_objects = object; 70 } 71 else { 72 _dl_last_object->next = object; 73 object->prev = _dl_last_object; 74 _dl_last_object = object; 75 } 76 77 object->load_dyn = dynp; 78 while(dynp->d_tag != DT_NULL) { 79 if(dynp->d_tag < DT_NUM) { 80 object->Dyn.info[dynp->d_tag] = dynp->d_un.d_val; 81 } 82 else if(dynp->d_tag >= DT_LOPROC && dynp->d_tag < DT_LOPROC + DT_NUM) { 83 object->Dyn.info[dynp->d_tag + DT_NUM - DT_LOPROC] = dynp-> 84 d_un.d_val; 85 } 86 if(dynp->d_tag == DT_TEXTREL) 87 object->dyn.textrel = 1; 88 if(dynp->d_tag == DT_SYMBOLIC) 89 object->dyn.symbolic = 1; 90 if(dynp->d_tag == DT_BIND_NOW) 91 object->dyn.bind_now = 1; 92 dynp++; 93 } 94 95 /* 96 * Now relocate all pointer to dynamic info, but only 97 * the ones which has pointer values. 98 */ 99 if(object->Dyn.info[DT_PLTGOT]) 100 object->Dyn.info[DT_PLTGOT] += loff; 101 if(object->Dyn.info[DT_HASH]) 102 object->Dyn.info[DT_HASH] += loff; 103 if(object->Dyn.info[DT_STRTAB]) 104 object->Dyn.info[DT_STRTAB] += loff; 105 if(object->Dyn.info[DT_SYMTAB]) 106 object->Dyn.info[DT_SYMTAB] += loff; 107 if(object->Dyn.info[DT_RELA]) 108 object->Dyn.info[DT_RELA] += loff; 109 if(object->Dyn.info[DT_SONAME]) 110 object->Dyn.info[DT_SONAME] += loff; 111 if(object->Dyn.info[DT_RPATH]) 112 object->Dyn.info[DT_RPATH] += object->Dyn.info[DT_STRTAB]; 113 if(object->Dyn.info[DT_REL]) 114 object->Dyn.info[DT_REL] += loff; 115 if(object->Dyn.info[DT_INIT]) 116 object->Dyn.info[DT_INIT] += loff; 117 if(object->Dyn.info[DT_FINI]) 118 object->Dyn.info[DT_FINI] += loff; 119 if(object->Dyn.info[DT_JMPREL]) 120 object->Dyn.info[DT_JMPREL] += loff; 121 122 object->buckets = object->dyn.hash; 123 if(object->buckets != 0) { 124 object->nbuckets = *object->buckets++; 125 object->nchains = *object->buckets++; 126 object->chains = object->buckets + object->nbuckets; 127 } 128 129 if(dl_data) { 130 object->phdrp = (Elf_Phdr *) dl_data[AUX_phdr]; 131 object->phdrc = dl_data[AUX_phnum]; 132 } 133 object->obj_type = objtype; 134 object->load_addr = laddr; 135 object->load_offs = loff; 136 object->load_name = (char *)_dl_malloc(_dl_strlen(objname) + 1); 137 _dl_strcpy(object->load_name, objname); 138 object->refcount = 1; 139 140 return(object); 141 } 142 143 144 void 145 _dl_remove_object(elf_object_t *object) 146 { 147 elf_object_t *depobj; 148 149 object->prev->next = object->next; 150 if(object->next) { 151 object->next->prev = object->prev; 152 } 153 if(object->load_name) { 154 _dl_free(object->load_name); 155 } 156 while((depobj = object->dep_next)) { 157 object->dep_next = object->dep_next->dep_next; 158 _dl_free(depobj); 159 } 160 _dl_free(object); 161 } 162 163 164 elf_object_t * 165 _dl_lookup_object(const char *name) 166 { 167 elf_object_t *object; 168 169 object = _dl_objects; 170 while(object) { 171 if(_dl_strcmp(name, object->load_name) == 0) { 172 return(object); 173 } 174 object = object->next; 175 } 176 return(0); 177 } 178 179 180 Elf_Addr 181 _dl_find_symbol(const char *name, elf_object_t *startlook, 182 const Elf_Sym **ref, int myself, int warnnotfound) 183 { 184 u_int32_t h = 0; 185 const char *p = name; 186 elf_object_t *object; 187 const Elf_Sym *weak_sym = 0; 188 Elf_Addr weak_offs = 0; 189 190 while(*p) { 191 u_int32_t g; 192 h = (h << 4) + *p++; 193 if((g = h & 0xf0000000)) { 194 h ^= g >> 24; 195 } 196 h &= ~g; 197 } 198 199 for(object = startlook; object; object = (myself ? 0 : object->next)) { 200 const Elf_Sym *symt; 201 const char *strt; 202 u_int32_t si; 203 204 symt = object->dyn.symtab; 205 strt = object->dyn.strtab; 206 207 for(si = object->buckets[h % object->nbuckets]; 208 si != STN_UNDEF; si = object->chains[si]) { 209 const Elf_Sym *sym = symt + si; 210 211 if(sym->st_value == 0 || 212 sym->st_shndx == SHN_UNDEF) { 213 continue; 214 } 215 216 if(ELF_ST_TYPE(sym->st_info) != STT_NOTYPE && 217 ELF_ST_TYPE(sym->st_info) != STT_OBJECT && 218 ELF_ST_TYPE(sym->st_info) != STT_FUNC) { 219 continue; 220 } 221 222 if(sym != *ref && _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 } 230 else if(ELF_ST_BIND(sym->st_info) == STB_WEAK) { 231 if(!weak_sym) { 232 weak_sym = sym; 233 weak_offs = object->load_offs; 234 } 235 } 236 } 237 } 238 if (warnnotfound) { 239 if(!weak_sym && 240 *ref && ELF_ST_BIND((*ref)->st_info) != STB_WEAK) 241 { 242 _dl_printf("%s: undefined symbol '%s'\n", 243 _dl_progname, name); 244 } 245 } 246 *ref = weak_sym; 247 return(weak_offs); 248 } 249 250