mdreloc.c revision 1.17
1 /* $NetBSD: mdreloc.c,v 1.17 2002/09/15 01:08:04 thorpej Exp $ */ 2 3 #include <sys/types.h> 4 #include <sys/stat.h> 5 6 #include "debug.h" 7 #include "rtld.h" 8 9 void _rtld_bind_start(void); 10 void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); 11 12 void 13 _rtld_setup_pltgot(const Obj_Entry *obj) 14 { 15 obj->pltgot[1] = (Elf_Addr) obj; 16 obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; 17 } 18 19 void 20 _rtld_relocate_nonplt_self(dynp, relocbase) 21 Elf_Dyn *dynp; 22 Elf_Addr relocbase; 23 { 24 const Elf_Rel *rel = 0, *rellim; 25 Elf_Addr relsz = 0; 26 Elf_Addr *where; 27 28 for (; dynp->d_tag != DT_NULL; dynp++) { 29 switch (dynp->d_tag) { 30 case DT_REL: 31 rel = (const Elf_Rel *)(relocbase + dynp->d_un.d_ptr); 32 break; 33 case DT_RELSZ: 34 relsz = dynp->d_un.d_val; 35 break; 36 } 37 } 38 rellim = (const Elf_Rel *)((caddr_t)rel + relsz); 39 for (; rel < rellim; rel++) { 40 where = (Elf_Addr *)(relocbase + rel->r_offset); 41 *where += (Elf_Addr)relocbase; 42 } 43 } 44 45 /* 46 * It is possible for the compiler to emit relocations for unaligned data. 47 * We handle this situation with these inlines. 48 */ 49 #define RELOC_ALIGNED_P(x) \ 50 (((uintptr_t)(x) & (sizeof(void *) - 1)) == 0) 51 52 static __inline Elf_Addr 53 load_ptr(void *where) 54 { 55 Elf_Addr res; 56 57 memcpy(&res, where, sizeof(res)); 58 59 return (res); 60 } 61 62 static __inline void 63 store_ptr(void *where, Elf_Addr val) 64 { 65 66 memcpy(where, &val, sizeof(val)); 67 } 68 69 int 70 _rtld_relocate_nonplt_objects(obj, self) 71 const Obj_Entry *obj; 72 bool self; 73 { 74 const Elf_Rel *rel; 75 76 if (self) 77 return 0; 78 79 for (rel = obj->rel; rel < obj->rellim; rel++) { 80 Elf_Addr *where; 81 const Elf_Sym *def; 82 const Obj_Entry *defobj; 83 Elf_Addr tmp; 84 unsigned long symnum; 85 86 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 87 symnum = ELF_R_SYM(rel->r_info); 88 89 switch (ELF_R_TYPE(rel->r_info)) { 90 case R_TYPE(NONE): 91 break; 92 93 #if 1 /* XXX should not occur */ 94 case R_TYPE(PC24): { /* word32 S - P + A */ 95 Elf32_Sword addend; 96 97 /* 98 * Extract addend and sign-extend if needed. 99 */ 100 addend = *where; 101 if (addend & 0x00800000) 102 addend |= 0xff000000; 103 104 def = _rtld_find_symdef(symnum, obj, &defobj, false); 105 if (def == NULL) 106 return -1; 107 tmp = (Elf_Addr)obj->relocbase + def->st_value 108 - (Elf_Addr)where + (addend << 2); 109 if ((tmp & 0xfe000000) != 0xfe000000 && 110 (tmp & 0xfe000000) != 0) { 111 _rtld_error( 112 "%s: R_ARM_PC24 relocation @ %p to %s failed " 113 "(displacement %ld (%#lx) out of range)", 114 obj->path, where, 115 obj->strtab + obj->symtab[symnum].st_name, 116 (long) tmp, (long) tmp); 117 return -1; 118 } 119 tmp >>= 2; 120 *where = (*where & 0xff000000) | (tmp & 0x00ffffff); 121 rdbg(("PC24 %s in %s --> %p @ %p in %s", 122 obj->strtab + obj->symtab[symnum].st_name, 123 obj->path, (void *)*where, where, defobj->path)); 124 break; 125 } 126 #endif 127 128 case R_TYPE(ABS32): /* word32 B + S + A */ 129 case R_TYPE(GLOB_DAT): /* word32 B + S */ 130 def = _rtld_find_symdef(symnum, obj, &defobj, false); 131 if (def == NULL) 132 return -1; 133 if (__predict_true(RELOC_ALIGNED_P(where))) { 134 tmp = *where + (Elf_Addr)defobj->relocbase + 135 def->st_value; 136 *where = tmp; 137 } else { 138 tmp = load_ptr(where) + 139 (Elf_Addr)defobj->relocbase + 140 def->st_value; 141 store_ptr(where, tmp); 142 } 143 rdbg(("ABS32/GLOB_DAT %s in %s --> %p @ %p in %s", 144 obj->strtab + obj->symtab[symnum].st_name, 145 obj->path, (void *)tmp, where, defobj->path)); 146 break; 147 148 case R_TYPE(RELATIVE): /* word32 B + A */ 149 if (__predict_true(RELOC_ALIGNED_P(where))) { 150 tmp = *where + (Elf_Addr)obj->relocbase; 151 *where = tmp; 152 } else { 153 tmp = load_ptr(where) + 154 (Elf_Addr)obj->relocbase; 155 store_ptr(where, tmp); 156 } 157 rdbg(("RELATIVE in %s --> %p", obj->path, 158 (void *)tmp)); 159 break; 160 161 case R_TYPE(COPY): 162 /* 163 * These are deferred until all other relocations have 164 * been done. All we do here is make sure that the 165 * COPY relocation is not in a shared library. They 166 * are allowed only in executable files. 167 */ 168 if (obj->isdynamic) { 169 _rtld_error( 170 "%s: Unexpected R_COPY relocation in shared library", 171 obj->path); 172 return -1; 173 } 174 rdbg(("COPY (avoid in main)")); 175 break; 176 177 default: 178 rdbg(("sym = %lu, type = %lu, offset = %p, " 179 "contents = %p, symbol = %s", 180 symnum, (u_long)ELF_R_TYPE(rel->r_info), 181 (void *)rel->r_offset, (void *)load_ptr(where), 182 obj->strtab + obj->symtab[symnum].st_name)); 183 _rtld_error("%s: Unsupported relocation type %ld " 184 "in non-PLT relocations\n", 185 obj->path, (u_long) ELF_R_TYPE(rel->r_info)); 186 return -1; 187 } 188 } 189 return 0; 190 } 191 192 int 193 _rtld_relocate_plt_lazy(obj) 194 const Obj_Entry *obj; 195 { 196 const Elf_Rel *rel; 197 198 if (!obj->isdynamic) 199 return 0; 200 201 for (rel = obj->pltrel; rel < obj->pltrellim; rel++) { 202 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 203 204 assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JUMP_SLOT)); 205 206 /* Just relocate the GOT slots pointing into the PLT */ 207 *where += (Elf_Addr)obj->relocbase; 208 rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where)); 209 } 210 211 return 0; 212 } 213 214 int 215 _rtld_relocate_plt_object(obj, rela, addrp) 216 const Obj_Entry *obj; 217 const Elf_Rela *rela; 218 caddr_t *addrp; 219 { 220 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 221 Elf_Addr new_value; 222 const Elf_Sym *def; 223 const Obj_Entry *defobj; 224 225 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JUMP_SLOT)); 226 227 def = _rtld_find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, true); 228 if (def == NULL) 229 return -1; 230 231 new_value = (Elf_Addr)(defobj->relocbase + def->st_value); 232 rdbg(("bind now/fixup in %s --> old=%p new=%p", 233 defobj->strtab + def->st_name, (void *)*where, (void *)new_value)); 234 if (*where != new_value) 235 *where = new_value; 236 237 *addrp = (caddr_t)new_value; 238 return 0; 239 } 240
Indexes created Tue Sep 30 11:09:46 GMT 2025