mdreloc.c revision 1.34
1 /* $NetBSD: mdreloc.c,v 1.34 2011/03/25 18:07:05 joerg Exp $ */ 2 3 #include <sys/cdefs.h> 4 #ifndef lint 5 __RCSID("$NetBSD: mdreloc.c,v 1.34 2011/03/25 18:07:05 joerg Exp $"); 6 #endif /* not lint */ 7 8 #include <sys/types.h> 9 #include <sys/ucontext.h> 10 11 #include "debug.h" 12 #include "rtld.h" 13 14 void _rtld_bind_start(void); 15 void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); 16 caddr_t _rtld_bind(const Obj_Entry *, Elf_Word); 17 18 void 19 _rtld_setup_pltgot(const Obj_Entry *obj) 20 { 21 obj->pltgot[1] = (Elf_Addr) obj; 22 obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; 23 } 24 25 void 26 _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) 27 { 28 const Elf_Rel *rel = 0, *rellim; 29 Elf_Addr relsz = 0; 30 Elf_Addr *where; 31 32 for (; dynp->d_tag != DT_NULL; dynp++) { 33 switch (dynp->d_tag) { 34 case DT_REL: 35 rel = (const Elf_Rel *)(relocbase + dynp->d_un.d_ptr); 36 break; 37 case DT_RELSZ: 38 relsz = dynp->d_un.d_val; 39 break; 40 } 41 } 42 if (rel == 0 || relsz == 0) 43 return; 44 rellim = (const Elf_Rel *)((const uint8_t *)rel + relsz); 45 for (; rel < rellim; rel++) { 46 where = (Elf_Addr *)(relocbase + rel->r_offset); 47 *where += (Elf_Addr)relocbase; 48 } 49 } 50 51 int 52 _rtld_relocate_nonplt_objects(Obj_Entry *obj) 53 { 54 const Elf_Rel *rel; 55 Elf_Addr target = 0; 56 57 for (rel = obj->rel; rel < obj->rellim; rel++) { 58 Elf_Addr *where; 59 const Elf_Sym *def; 60 const Obj_Entry *defobj; 61 Elf_Addr tmp; 62 unsigned long symnum; 63 64 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 65 symnum = ELF_R_SYM(rel->r_info); 66 67 switch (ELF_R_TYPE(rel->r_info)) { 68 case R_TYPE(NONE): 69 break; 70 71 #if 1 /* XXX should not occur */ 72 case R_TYPE(PC32): 73 def = _rtld_find_symdef(symnum, obj, &defobj, false); 74 if (def == NULL) 75 return -1; 76 target = (Elf_Addr)(defobj->relocbase + def->st_value); 77 78 *where += target - (Elf_Addr)where; 79 rdbg(("PC32 %s in %s --> %p in %s", 80 obj->strtab + obj->symtab[symnum].st_name, 81 obj->path, (void *)*where, defobj->path)); 82 break; 83 84 case R_TYPE(GOT32): 85 #endif 86 case R_TYPE(32): 87 case R_TYPE(GLOB_DAT): 88 def = _rtld_find_symdef(symnum, obj, &defobj, false); 89 if (def == NULL) 90 return -1; 91 target = (Elf_Addr)(defobj->relocbase + def->st_value); 92 93 tmp = target + *where; 94 if (*where != tmp) 95 *where = tmp; 96 rdbg(("32/GLOB_DAT %s in %s --> %p in %s", 97 obj->strtab + obj->symtab[symnum].st_name, 98 obj->path, (void *)*where, defobj->path)); 99 break; 100 101 case R_TYPE(RELATIVE): 102 *where += (Elf_Addr)obj->relocbase; 103 rdbg(("RELATIVE in %s --> %p", obj->path, 104 (void *)*where)); 105 break; 106 107 case R_TYPE(COPY): 108 /* 109 * These are deferred until all other relocations have 110 * been done. All we do here is make sure that the 111 * COPY relocation is not in a shared library. They 112 * are allowed only in executable files. 113 */ 114 if (obj->isdynamic) { 115 _rtld_error( 116 "%s: Unexpected R_COPY relocation in shared library", 117 obj->path); 118 return -1; 119 } 120 rdbg(("COPY (avoid in main)")); 121 break; 122 123 case R_TYPE(TLS_TPOFF): 124 def = _rtld_find_symdef(symnum, obj, &defobj, false); 125 if (def == NULL) 126 return -1; 127 128 if (!defobj->tls_done && 129 _rtld_tls_offset_allocate(obj)) 130 return -1; 131 132 *where = (Elf_Addr)(def->st_value - defobj->tlsoffset); 133 134 rdbg(("TLS_TPOFF %s in %s --> %p", 135 obj->strtab + obj->symtab[symnum].st_name, 136 obj->path, (void *)*where)); 137 break; 138 139 case R_TYPE(TLS_DTPMOD32): 140 def = _rtld_find_symdef(symnum, obj, &defobj, false); 141 if (def == NULL) 142 return -1; 143 144 *where = (Elf_Addr)(defobj->tlsindex); 145 146 rdbg(("TLS_DTPMOD32 %s in %s --> %p", 147 obj->strtab + obj->symtab[symnum].st_name, 148 obj->path, (void *)*where)); 149 break; 150 151 case R_TYPE(TLS_DTPOFF32): 152 def = _rtld_find_symdef(symnum, obj, &defobj, false); 153 if (def == NULL) 154 return -1; 155 156 *where = (Elf_Addr)(def->st_value); 157 158 rdbg(("TLS_DTPOFF32 %s in %s --> %p", 159 obj->strtab + obj->symtab[symnum].st_name, 160 obj->path, (void *)*where)); 161 162 break; 163 164 default: 165 rdbg(("sym = %lu, type = %lu, offset = %p, " 166 "contents = %p, symbol = %s", 167 symnum, (u_long)ELF_R_TYPE(rel->r_info), 168 (void *)rel->r_offset, (void *)*where, 169 obj->strtab + obj->symtab[symnum].st_name)); 170 _rtld_error("%s: Unsupported relocation type %ld " 171 "in non-PLT relocations", 172 obj->path, (u_long) ELF_R_TYPE(rel->r_info)); 173 return -1; 174 } 175 } 176 return 0; 177 } 178 179 int 180 _rtld_relocate_plt_lazy(const Obj_Entry *obj) 181 { 182 const Elf_Rel *rel; 183 184 if (!obj->relocbase) 185 return 0; 186 187 for (rel = obj->pltrel; rel < obj->pltrellim; rel++) { 188 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 189 190 assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JMP_SLOT)); 191 192 /* Just relocate the GOT slots pointing into the PLT */ 193 *where += (Elf_Addr)obj->relocbase; 194 rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where)); 195 } 196 197 return 0; 198 } 199 200 static inline int 201 _rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rel *rel, 202 Elf_Addr *tp) 203 { 204 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 205 Elf_Addr target; 206 const Elf_Sym *def; 207 const Obj_Entry *defobj; 208 unsigned long info = rel->r_info; 209 210 assert(ELF_R_TYPE(info) == R_TYPE(JMP_SLOT)); 211 212 def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL); 213 if (__predict_false(def == NULL)) 214 return -1; 215 if (__predict_false(def == &_rtld_sym_zero)) 216 return 0; 217 218 target = (Elf_Addr)(defobj->relocbase + def->st_value); 219 rdbg(("bind now/fixup in %s --> old=%p new=%p", 220 defobj->strtab + def->st_name, (void *)*where, 221 (void *)target)); 222 if (*where != target) 223 *where = target; 224 if (tp) 225 *tp = target; 226 return 0; 227 } 228 229 caddr_t 230 _rtld_bind(const Obj_Entry *obj, Elf_Word reloff) 231 { 232 const Elf_Rel *rel = (const Elf_Rel *)((const uint8_t *)obj->pltrel 233 + reloff); 234 Elf_Addr new_value; 235 int err; 236 237 new_value = 0; /* XXX gcc */ 238 239 _rtld_shared_enter(); 240 err = _rtld_relocate_plt_object(obj, rel, &new_value); 241 if (err) 242 _rtld_die(); 243 _rtld_shared_exit(); 244 245 return (caddr_t)new_value; 246 } 247 248 int 249 _rtld_relocate_plt_objects(const Obj_Entry *obj) 250 { 251 const Elf_Rel *rel; 252 int err = 0; 253 254 for (rel = obj->pltrel; rel < obj->pltrellim; rel++) { 255 err = _rtld_relocate_plt_object(obj, rel, NULL); 256 if (err) 257 break; 258 } 259 return err; 260 } 261 262 /* 263 * i386 specific GNU variant of __tls_get_addr using register based 264 * argument passing. 265 */ 266 #define DTV_MAX_INDEX(dtv) ((size_t)((dtv)[-1])) 267 268 __dso_public __attribute__((__regparm__(1))) void * 269 ___tls_get_addr(void *arg_) 270 { 271 size_t *arg = (size_t *)arg_; 272 void **dtv; 273 struct tls_tcb *tcb = __lwp_getprivate_fast(); 274 size_t idx = arg[0], offset = arg[1]; 275 276 dtv = tcb->tcb_dtv; 277 278 if (__predict_true(idx < DTV_MAX_INDEX(dtv) && dtv[idx] != NULL)) 279 return (uint8_t *)dtv[idx] + offset; 280 281 return _rtld_tls_get_addr(tcb, idx, offset); 282 } 283
Indexes created Wed Oct 01 12:09:54 GMT 2025