mdreloc.c revision 1.26
1 /* $NetBSD: mdreloc.c,v 1.26 2010/01/14 11:58:32 skrll Exp $ */ 2 3 #include <sys/cdefs.h> 4 #ifndef lint 5 __RCSID("$NetBSD: mdreloc.c,v 1.26 2010/01/14 11:58:32 skrll Exp $"); 6 #endif /* not lint */ 7 8 #include <sys/cdefs.h> 9 #ifndef lint 10 __RCSID("$NetBSD: mdreloc.c,v 1.26 2010/01/14 11:58:32 skrll Exp $"); 11 #endif /* not lint */ 12 13 #include <sys/types.h> 14 #include <sys/stat.h> 15 16 #include "debug.h" 17 #include "rtld.h" 18 19 void _rtld_bind_start(void); 20 void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); 21 caddr_t _rtld_bind(const Obj_Entry *, Elf_Word); 22 static inline int _rtld_relocate_plt_object(const Obj_Entry *, 23 const Elf_Rela *, Elf_Addr *); 24 25 26 void 27 _rtld_setup_pltgot(const Obj_Entry *obj) 28 { 29 obj->pltgot[1] = (Elf_Addr) obj; 30 obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; 31 } 32 33 void 34 _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) 35 { 36 const Elf_Rela *rela = 0, *relalim; 37 Elf_Addr relasz = 0; 38 Elf_Addr *where; 39 40 for (; dynp->d_tag != DT_NULL; dynp++) { 41 switch (dynp->d_tag) { 42 case DT_RELA: 43 rela = (const Elf_Rela *)(relocbase + dynp->d_un.d_ptr); 44 break; 45 case DT_RELASZ: 46 relasz = dynp->d_un.d_val; 47 break; 48 } 49 } 50 relalim = (const Elf_Rela *)((const uint8_t *)rela + relasz); 51 for (; rela < relalim; rela++) { 52 where = (Elf_Addr *)(relocbase + rela->r_offset); 53 *where += (Elf_Addr)relocbase; 54 } 55 } 56 57 int 58 _rtld_relocate_nonplt_objects(const Obj_Entry *obj) 59 { 60 const Elf_Rela *rela; 61 62 for (rela = obj->rela; rela < obj->relalim; rela++) { 63 Elf_Addr *where; 64 const Elf_Sym *def; 65 const Obj_Entry *defobj; 66 Elf_Addr tmp; 67 unsigned long symnum; 68 69 where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 70 symnum = ELF_R_SYM(rela->r_info); 71 72 switch (ELF_R_TYPE(rela->r_info)) { 73 case R_TYPE(NONE): 74 break; 75 76 #if 1 /* XXX should not occur */ 77 case R_TYPE(PC32): 78 def = _rtld_find_symdef(symnum, obj, &defobj, false); 79 if (def == NULL) 80 return -1; 81 82 tmp = (Elf_Addr)(defobj->relocbase + def->st_value + 83 rela->r_addend) - (Elf_Addr)where; 84 if (*where != tmp) 85 *where = tmp; 86 rdbg(("PC32 %s in %s --> %p in %s", 87 obj->strtab + obj->symtab[symnum].st_name, 88 obj->path, (void *)*where, defobj->path)); 89 break; 90 91 case R_TYPE(GOT32): 92 #endif 93 case R_TYPE(32): 94 case R_TYPE(GLOB_DAT): 95 def = _rtld_find_symdef(symnum, obj, &defobj, false); 96 if (def == NULL) 97 return -1; 98 99 tmp = (Elf_Addr)(defobj->relocbase + def->st_value + 100 rela->r_addend); 101 if (*where != tmp) 102 *where = tmp; 103 rdbg(("32/GLOB_DAT %s in %s --> %p in %s", 104 obj->strtab + obj->symtab[symnum].st_name, 105 obj->path, (void *)*where, defobj->path)); 106 break; 107 108 case R_TYPE(RELATIVE): 109 *where += (Elf_Addr)obj->relocbase; 110 rdbg(("RELATIVE in %s --> %p", obj->path, 111 (void *)*where)); 112 break; 113 114 case R_TYPE(COPY): 115 /* 116 * These are deferred until all other relocations have 117 * been done. All we do here is make sure that the 118 * COPY relocation is not in a shared library. They 119 * are allowed only in executable files. 120 */ 121 if (obj->isdynamic) { 122 _rtld_error( 123 "%s: Unexpected R_COPY relocation in shared library", 124 obj->path); 125 return -1; 126 } 127 rdbg(("COPY (avoid in main)")); 128 break; 129 130 default: 131 rdbg(("sym = %lu, type = %lu, offset = %p, " 132 "addend = %p, contents = %p, symbol = %s", 133 symnum, (u_long)ELF_R_TYPE(rela->r_info), 134 (void *)rela->r_offset, (void *)rela->r_addend, 135 (void *)*where, 136 obj->strtab + obj->symtab[symnum].st_name)); 137 _rtld_error("%s: Unsupported relocation type %ld " 138 "in non-PLT relocations", 139 obj->path, (u_long) ELF_R_TYPE(rela->r_info)); 140 return -1; 141 } 142 } 143 return 0; 144 } 145 146 int 147 _rtld_relocate_plt_lazy(const Obj_Entry *obj) 148 { 149 const Elf_Rela *rela; 150 151 if (!obj->relocbase) 152 return 0; 153 154 for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) { 155 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 156 157 assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT)); 158 159 /* Just relocate the GOT slots pointing into the PLT */ 160 *where += (Elf_Addr)obj->relocbase; 161 rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where)); 162 } 163 164 return 0; 165 } 166 167 static inline int 168 _rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, 169 Elf_Addr *tp) 170 { 171 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset); 172 Elf_Addr new_value; 173 const Elf_Sym *def; 174 const Obj_Entry *defobj; 175 unsigned long info = rela->r_info; 176 177 assert(ELF_R_TYPE(info) == R_TYPE(JMP_SLOT)); 178 179 def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL); 180 if (__predict_false(def == NULL)) 181 return -1; 182 if (__predict_false(def == &_rtld_sym_zero)) 183 return 0; 184 185 assert(rela->r_addend == 0); 186 new_value = (Elf_Addr)(defobj->relocbase + def->st_value + 187 rela->r_addend); 188 rdbg(("bind now/fixup in %s --> old=%p new=%p", 189 defobj->strtab + def->st_name, (void *)*where, (void *)new_value)); 190 if (*where != new_value) 191 *where = new_value; 192 193 if (tp) 194 *tp = new_value - rela->r_addend; 195 196 return 0; 197 } 198 199 caddr_t 200 _rtld_bind(const Obj_Entry *obj, Elf_Word reloff) 201 { 202 const Elf_Rela *rela = (const Elf_Rela *)((const uint8_t *)obj->pltrela + reloff); 203 Elf_Addr result; 204 int err; 205 206 result = 0; /* XXX gcc */ 207 208 err = _rtld_relocate_plt_object(obj, rela, &result); 209 if (err) 210 _rtld_die(); 211 212 return (caddr_t)result; 213 } 214 215 int 216 _rtld_relocate_plt_objects(const Obj_Entry *obj) 217 { 218 const Elf_Rela *rela; 219 220 for (rela = obj->pltrela; rela < obj->pltrelalim; rela++) 221 if (_rtld_relocate_plt_object(obj, rela, NULL) < 0) 222 return -1; 223 224 return 0; 225 } 226
Indexes created Tue Sep 30 10:09:55 GMT 2025