mdreloc.c revision 1.16
1 /* $NetBSD: mdreloc.c,v 1.16 2002/09/25 07:27:52 mycroft 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 caddr_t _rtld_bind __P((const Obj_Entry *, Elf_Word)); 12 13 void 14 _rtld_setup_pltgot(const Obj_Entry *obj) 15 { 16 obj->pltgot[1] = (Elf_Addr) obj; 17 obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; 18 } 19 20 void 21 _rtld_relocate_nonplt_self(dynp, relocbase) 22 Elf_Dyn *dynp; 23 Elf_Addr relocbase; 24 { 25 const Elf_Rel *rel = 0, *rellim; 26 Elf_Addr relsz = 0; 27 Elf_Addr *where; 28 29 for (; dynp->d_tag != DT_NULL; dynp++) { 30 switch (dynp->d_tag) { 31 case DT_REL: 32 rel = (const Elf_Rel *)(relocbase + dynp->d_un.d_ptr); 33 break; 34 case DT_RELSZ: 35 relsz = dynp->d_un.d_val; 36 break; 37 } 38 } 39 rellim = (const Elf_Rel *)((caddr_t)rel + relsz); 40 for (; rel < rellim; rel++) { 41 where = (Elf_Addr *)(relocbase + rel->r_offset); 42 *where += (Elf_Addr)relocbase; 43 } 44 } 45 46 int 47 _rtld_relocate_nonplt_objects(obj, self) 48 const Obj_Entry *obj; 49 bool self; 50 { 51 const Elf_Rel *rel; 52 #define COMBRELOC 53 #ifdef COMBRELOC 54 unsigned long lastsym = -1; 55 #endif 56 Elf_Addr target; 57 58 if (self) 59 return 0; 60 61 for (rel = obj->rel; rel < obj->rellim; rel++) { 62 Elf_Addr *where; 63 const Elf_Sym *def; 64 const Obj_Entry *defobj; 65 Elf_Addr tmp; 66 unsigned long symnum; 67 68 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 69 symnum = ELF_R_SYM(rel->r_info); 70 71 switch (ELF_R_TYPE(rel->r_info)) { 72 case R_TYPE(NONE): 73 break; 74 75 #if 1 /* XXX should not occur */ 76 case R_TYPE(PC32): 77 #ifdef COMBRELOC 78 if (symnum != lastsym) { 79 #endif 80 def = _rtld_find_symdef(symnum, obj, &defobj, 81 false); 82 if (def == NULL) 83 return -1; 84 target = (Elf_Addr)(defobj->relocbase + 85 def->st_value); 86 #ifdef COMBRELOC 87 lastsym = symnum; 88 } 89 #endif 90 91 *where += target - (Elf_Addr)where; 92 rdbg(("PC32 %s in %s --> %p in %s", 93 obj->strtab + obj->symtab[symnum].st_name, 94 obj->path, (void *)*where, defobj->path)); 95 break; 96 97 case R_TYPE(GOT32): 98 #endif 99 case R_TYPE(32): 100 case R_TYPE(GLOB_DAT): 101 #ifdef COMBRELOC 102 if (symnum != lastsym) { 103 #endif 104 def = _rtld_find_symdef(symnum, obj, &defobj, 105 false); 106 if (def == NULL) 107 return -1; 108 target = (Elf_Addr)(defobj->relocbase + 109 def->st_value); 110 #ifdef COMBRELOC 111 lastsym = symnum; 112 } 113 #endif 114 115 tmp = target + *where; 116 if (*where != tmp) 117 *where = tmp; 118 rdbg(("32/GLOB_DAT %s in %s --> %p in %s", 119 obj->strtab + obj->symtab[symnum].st_name, 120 obj->path, (void *)*where, defobj->path)); 121 break; 122 123 case R_TYPE(RELATIVE): 124 *where += (Elf_Addr)obj->relocbase; 125 rdbg(("RELATIVE in %s --> %p", obj->path, 126 (void *)*where)); 127 break; 128 129 case R_TYPE(COPY): 130 /* 131 * These are deferred until all other relocations have 132 * been done. All we do here is make sure that the 133 * COPY relocation is not in a shared library. They 134 * are allowed only in executable files. 135 */ 136 if (obj->isdynamic) { 137 _rtld_error( 138 "%s: Unexpected R_COPY relocation in shared library", 139 obj->path); 140 return -1; 141 } 142 rdbg(("COPY (avoid in main)")); 143 break; 144 145 default: 146 rdbg(("sym = %lu, type = %lu, offset = %p, " 147 "contents = %p, symbol = %s", 148 symnum, (u_long)ELF_R_TYPE(rel->r_info), 149 (void *)rel->r_offset, (void *)*where, 150 obj->strtab + obj->symtab[symnum].st_name)); 151 _rtld_error("%s: Unsupported relocation type %ld " 152 "in non-PLT relocations\n", 153 obj->path, (u_long) ELF_R_TYPE(rel->r_info)); 154 return -1; 155 } 156 } 157 return 0; 158 } 159 160 int 161 _rtld_relocate_plt_lazy(obj) 162 const Obj_Entry *obj; 163 { 164 const Elf_Rel *rel; 165 166 if (!obj->isdynamic) 167 return 0; 168 169 for (rel = obj->pltrel; rel < obj->pltrellim; rel++) { 170 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 171 172 assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JMP_SLOT)); 173 174 /* Just relocate the GOT slots pointing into the PLT */ 175 *where += (Elf_Addr)obj->relocbase; 176 rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where)); 177 } 178 179 return 0; 180 } 181 182 caddr_t 183 _rtld_bind(obj, reloff) 184 const Obj_Entry *obj; 185 Elf_Word reloff; 186 { 187 const Elf_Rel *rel = (const Elf_Rel *)((caddr_t)obj->pltrel + reloff); 188 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 189 Elf_Addr new_value; 190 const Elf_Sym *def; 191 const Obj_Entry *defobj; 192 193 assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JMP_SLOT)); 194 195 def = _rtld_find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true); 196 if (def == NULL) 197 _rtld_die(); 198 199 new_value = (Elf_Addr)(defobj->relocbase + def->st_value); 200 rdbg(("bind now/fixup in %s --> old=%p new=%p", 201 defobj->strtab + def->st_name, (void *)*where, (void *)new_value)); 202 if (*where != new_value) 203 *where = new_value; 204 205 return (caddr_t)new_value; 206 } 207 208 int 209 _rtld_relocate_plt_objects(const Obj_Entry *obj) 210 { 211 const Elf_Rel *rel; 212 213 for (rel = obj->pltrel; rel < obj->pltrellim; rel++) { 214 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 215 Elf_Addr target; 216 const Elf_Sym *def; 217 const Obj_Entry *defobj; 218 219 assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JMP_SLOT)); 220 221 def = _rtld_find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, 222 true); 223 if (def == NULL) 224 return -1; 225 target = (Elf_Addr)(defobj->relocbase + def->st_value); 226 rdbg(("bind now/fixup in %s --> old=%p new=%p", 227 defobj->strtab + def->st_name, (void *)*where, 228 (void *)target)); 229 if (*where != target) 230 *where = target; 231 } 232 return 0; 233 } 234
Indexes created Tue Sep 30 11:09:46 GMT 2025