mdreloc.c revision 1.18
1 /* $NetBSD: mdreloc.c,v 1.18 2002/10/03 20:39:22 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) 48 const Obj_Entry *obj; 49 { 50 const Elf_Rel *rel; 51 #define COMBRELOC 52 #ifdef COMBRELOC 53 unsigned long lastsym = -1; 54 #endif 55 Elf_Addr target; 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 #ifdef COMBRELOC 74 if (symnum != lastsym) { 75 #endif 76 def = _rtld_find_symdef(symnum, obj, &defobj, 77 false); 78 if (def == NULL) 79 return -1; 80 target = (Elf_Addr)(defobj->relocbase + 81 def->st_value); 82 #ifdef COMBRELOC 83 lastsym = symnum; 84 } 85 #endif 86 87 *where += target - (Elf_Addr)where; 88 rdbg(("PC32 %s in %s --> %p in %s", 89 obj->strtab + obj->symtab[symnum].st_name, 90 obj->path, (void *)*where, defobj->path)); 91 break; 92 93 case R_TYPE(GOT32): 94 #endif 95 case R_TYPE(32): 96 case R_TYPE(GLOB_DAT): 97 #ifdef COMBRELOC 98 if (symnum != lastsym) { 99 #endif 100 def = _rtld_find_symdef(symnum, obj, &defobj, 101 false); 102 if (def == NULL) 103 return -1; 104 target = (Elf_Addr)(defobj->relocbase + 105 def->st_value); 106 #ifdef COMBRELOC 107 lastsym = symnum; 108 } 109 #endif 110 111 tmp = target + *where; 112 if (*where != tmp) 113 *where = tmp; 114 rdbg(("32/GLOB_DAT %s in %s --> %p in %s", 115 obj->strtab + obj->symtab[symnum].st_name, 116 obj->path, (void *)*where, defobj->path)); 117 break; 118 119 case R_TYPE(RELATIVE): 120 *where += (Elf_Addr)obj->relocbase; 121 rdbg(("RELATIVE in %s --> %p", obj->path, 122 (void *)*where)); 123 break; 124 125 case R_TYPE(COPY): 126 /* 127 * These are deferred until all other relocations have 128 * been done. All we do here is make sure that the 129 * COPY relocation is not in a shared library. They 130 * are allowed only in executable files. 131 */ 132 if (obj->isdynamic) { 133 _rtld_error( 134 "%s: Unexpected R_COPY relocation in shared library", 135 obj->path); 136 return -1; 137 } 138 rdbg(("COPY (avoid in main)")); 139 break; 140 141 default: 142 rdbg(("sym = %lu, type = %lu, offset = %p, " 143 "contents = %p, symbol = %s", 144 symnum, (u_long)ELF_R_TYPE(rel->r_info), 145 (void *)rel->r_offset, (void *)*where, 146 obj->strtab + obj->symtab[symnum].st_name)); 147 _rtld_error("%s: Unsupported relocation type %ld " 148 "in non-PLT relocations\n", 149 obj->path, (u_long) ELF_R_TYPE(rel->r_info)); 150 return -1; 151 } 152 } 153 return 0; 154 } 155 156 int 157 _rtld_relocate_plt_lazy(obj) 158 const Obj_Entry *obj; 159 { 160 const Elf_Rel *rel; 161 162 if (!obj->relocbase) 163 return 0; 164 165 for (rel = obj->pltrel; rel < obj->pltrellim; rel++) { 166 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 167 168 assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JMP_SLOT)); 169 170 /* Just relocate the GOT slots pointing into the PLT */ 171 *where += (Elf_Addr)obj->relocbase; 172 rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where)); 173 } 174 175 return 0; 176 } 177 178 caddr_t 179 _rtld_bind(obj, reloff) 180 const Obj_Entry *obj; 181 Elf_Word reloff; 182 { 183 const Elf_Rel *rel = (const Elf_Rel *)((caddr_t)obj->pltrel + reloff); 184 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 185 Elf_Addr new_value; 186 const Elf_Sym *def; 187 const Obj_Entry *defobj; 188 189 assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JMP_SLOT)); 190 191 def = _rtld_find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true); 192 if (def == NULL) 193 _rtld_die(); 194 195 new_value = (Elf_Addr)(defobj->relocbase + def->st_value); 196 rdbg(("bind now/fixup in %s --> old=%p new=%p", 197 defobj->strtab + def->st_name, (void *)*where, (void *)new_value)); 198 if (*where != new_value) 199 *where = new_value; 200 201 return (caddr_t)new_value; 202 } 203 204 int 205 _rtld_relocate_plt_objects(const Obj_Entry *obj) 206 { 207 const Elf_Rel *rel; 208 209 for (rel = obj->pltrel; rel < obj->pltrellim; rel++) { 210 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 211 Elf_Addr target; 212 const Elf_Sym *def; 213 const Obj_Entry *defobj; 214 215 assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JMP_SLOT)); 216 217 def = _rtld_find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, 218 true); 219 if (def == NULL) 220 return -1; 221 target = (Elf_Addr)(defobj->relocbase + def->st_value); 222 rdbg(("bind now/fixup in %s --> old=%p new=%p", 223 defobj->strtab + def->st_name, (void *)*where, 224 (void *)target)); 225 if (*where != target) 226 *where = target; 227 } 228 return 0; 229 } 230
Indexes created Tue Sep 30 07:10:03 GMT 2025