mdreloc.c revision 1.20
1 /* $NetBSD: mdreloc.c,v 1.20 2005/06/01 14:15:13 lukem 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(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(Elf_Dyn *dynp, Elf_Addr relocbase) 22 { 23 const Elf_Rel *rel = 0, *rellim; 24 Elf_Addr relsz = 0; 25 Elf_Addr *where; 26 27 for (; dynp->d_tag != DT_NULL; dynp++) { 28 switch (dynp->d_tag) { 29 case DT_REL: 30 rel = (const Elf_Rel *)(relocbase + dynp->d_un.d_ptr); 31 break; 32 case DT_RELSZ: 33 relsz = dynp->d_un.d_val; 34 break; 35 } 36 } 37 rellim = (const Elf_Rel *)((caddr_t)rel + relsz); 38 for (; rel < rellim; rel++) { 39 where = (Elf_Addr *)(relocbase + rel->r_offset); 40 *where += (Elf_Addr)relocbase; 41 } 42 } 43 44 int 45 _rtld_relocate_nonplt_objects(const Obj_Entry *obj) 46 { 47 const Elf_Rel *rel; 48 #define COMBRELOC 49 #ifdef COMBRELOC 50 unsigned long lastsym = -1; 51 #endif 52 Elf_Addr target = 0; 53 54 for (rel = obj->rel; rel < obj->rellim; rel++) { 55 Elf_Addr *where; 56 const Elf_Sym *def; 57 const Obj_Entry *defobj; 58 Elf_Addr tmp; 59 unsigned long symnum; 60 61 where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 62 symnum = ELF_R_SYM(rel->r_info); 63 64 switch (ELF_R_TYPE(rel->r_info)) { 65 case R_TYPE(NONE): 66 break; 67 68 #if 1 /* XXX should not occur */ 69 case R_TYPE(PC32): 70 #ifdef COMBRELOC 71 if (symnum != lastsym) { 72 #endif 73 def = _rtld_find_symdef(symnum, obj, &defobj, 74 false); 75 if (def == NULL) 76 return -1; 77 target = (Elf_Addr)(defobj->relocbase + 78 def->st_value); 79 #ifdef COMBRELOC 80 lastsym = symnum; 81 } 82 #endif 83 84 *where += target - (Elf_Addr)where; 85 rdbg(("PC32 %s in %s --> %p in %s", 86 obj->strtab + obj->symtab[symnum].st_name, 87 obj->path, (void *)*where, defobj->path)); 88 break; 89 90 case R_TYPE(GOT32): 91 #endif 92 case R_TYPE(32): 93 case R_TYPE(GLOB_DAT): 94 #ifdef COMBRELOC 95 if (symnum != lastsym) { 96 #endif 97 def = _rtld_find_symdef(symnum, obj, &defobj, 98 false); 99 if (def == NULL) 100 return -1; 101 target = (Elf_Addr)(defobj->relocbase + 102 def->st_value); 103 #ifdef COMBRELOC 104 lastsym = symnum; 105 } 106 #endif 107 108 tmp = target + *where; 109 if (*where != tmp) 110 *where = tmp; 111 rdbg(("32/GLOB_DAT %s in %s --> %p in %s", 112 obj->strtab + obj->symtab[symnum].st_name, 113 obj->path, (void *)*where, defobj->path)); 114 break; 115 116 case R_TYPE(RELATIVE): 117 *where += (Elf_Addr)obj->relocbase; 118 rdbg(("RELATIVE in %s --> %p", obj->path, 119 (void *)*where)); 120 break; 121 122 case R_TYPE(COPY): 123 /* 124 * These are deferred until all other relocations have 125 * been done. All we do here is make sure that the 126 * COPY relocation is not in a shared library. They 127 * are allowed only in executable files. 128 */ 129 if (obj->isdynamic) { 130 _rtld_error( 131 "%s: Unexpected R_COPY relocation in shared library", 132 obj->path); 133 return -1; 134 } 135 rdbg(("COPY (avoid in main)")); 136 break; 137 138 default: 139 rdbg(("sym = %lu, type = %lu, offset = %p, " 140 "contents = %p, symbol = %s", 141 symnum, (u_long)ELF_R_TYPE(rel->r_info), 142 (void *)rel->r_offset, (void *)*where, 143 obj->strtab + obj->symtab[symnum].st_name)); 144 _rtld_error("%s: Unsupported relocation type %ld " 145 "in non-PLT relocations\n", 146 obj->path, (u_long) ELF_R_TYPE(rel->r_info)); 147 return -1; 148 } 149 } 150 return 0; 151 } 152 153 int 154 _rtld_relocate_plt_lazy(const Obj_Entry *obj) 155 { 156 const Elf_Rel *rel; 157 158 if (!obj->relocbase) 159 return 0; 160 161 for (rel = obj->pltrel; rel < obj->pltrellim; rel++) { 162 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 163 164 assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JMP_SLOT)); 165 166 /* Just relocate the GOT slots pointing into the PLT */ 167 *where += (Elf_Addr)obj->relocbase; 168 rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where)); 169 } 170 171 return 0; 172 } 173 174 caddr_t 175 _rtld_bind(const Obj_Entry *obj, Elf_Word reloff) 176 { 177 const Elf_Rel *rel = (const Elf_Rel *)((caddr_t)obj->pltrel + reloff); 178 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 179 Elf_Addr new_value; 180 const Elf_Sym *def; 181 const Obj_Entry *defobj; 182 183 assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JMP_SLOT)); 184 185 def = _rtld_find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true); 186 if (def == NULL) 187 _rtld_die(); 188 189 new_value = (Elf_Addr)(defobj->relocbase + def->st_value); 190 rdbg(("bind now/fixup in %s --> old=%p new=%p", 191 defobj->strtab + def->st_name, (void *)*where, (void *)new_value)); 192 if (*where != new_value) 193 *where = new_value; 194 195 return (caddr_t)new_value; 196 } 197 198 int 199 _rtld_relocate_plt_objects(const Obj_Entry *obj) 200 { 201 const Elf_Rel *rel; 202 203 for (rel = obj->pltrel; rel < obj->pltrellim; rel++) { 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; 208 209 assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JMP_SLOT)); 210 211 def = _rtld_find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, 212 true); 213 if (def == NULL) 214 return -1; 215 target = (Elf_Addr)(defobj->relocbase + def->st_value); 216 rdbg(("bind now/fixup in %s --> old=%p new=%p", 217 defobj->strtab + def->st_name, (void *)*where, 218 (void *)target)); 219 if (*where != target) 220 *where = target; 221 } 222 return 0; 223 } 224
Indexes created Tue Sep 30 11:09:46 GMT 2025