mdreloc.c revision 1.22
1 /* $NetBSD: mdreloc.c,v 1.22 2006/03/18 23:09:34 christos Exp $ */ 2 3 #include <sys/cdefs.h> 4 #ifndef lint 5 __RCSID("$NetBSD: mdreloc.c,v 1.22 2006/03/18 23:09:34 christos Exp $"); 6 #endif /* not lint */ 7 8 #include <sys/types.h> 9 #include <sys/stat.h> 10 11 #include "debug.h" 12 #include "rtld.h" 13 14 void _rtld_bind_start(void); 15 void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr); 16 caddr_t _rtld_bind(const Obj_Entry *, Elf_Word); 17 18 void 19 _rtld_setup_pltgot(const Obj_Entry *obj) 20 { 21 obj->pltgot[1] = (Elf_Addr) obj; 22 obj->pltgot[2] = (Elf_Addr) &_rtld_bind_start; 23 } 24 25 void 26 _rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase) 27 { 28 const Elf_Rel *rel = 0, *rellim; 29 Elf_Addr relsz = 0; 30 Elf_Addr *where; 31 32 for (; dynp->d_tag != DT_NULL; dynp++) { 33 switch (dynp->d_tag) { 34 case DT_REL: 35 rel = (const Elf_Rel *)(relocbase + dynp->d_un.d_ptr); 36 break; 37 case DT_RELSZ: 38 relsz = dynp->d_un.d_val; 39 break; 40 } 41 } 42 if (rel == 0 || relsz == 0) 43 return; 44 rellim = (const Elf_Rel *)((caddr_t)rel + relsz); 45 for (; rel < rellim; rel++) { 46 where = (Elf_Addr *)(relocbase + rel->r_offset); 47 *where += (Elf_Addr)relocbase; 48 } 49 } 50 51 int 52 _rtld_relocate_nonplt_objects(const Obj_Entry *obj) 53 { 54 const Elf_Rel *rel; 55 #define COMBRELOC 56 #ifdef COMBRELOC 57 unsigned long lastsym = -1; 58 #endif 59 Elf_Addr target = 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(const Obj_Entry *obj) 162 { 163 const Elf_Rel *rel; 164 165 if (!obj->relocbase) 166 return 0; 167 168 for (rel = obj->pltrel; rel < obj->pltrellim; rel++) { 169 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 170 171 assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JMP_SLOT)); 172 173 /* Just relocate the GOT slots pointing into the PLT */ 174 *where += (Elf_Addr)obj->relocbase; 175 rdbg(("fixup !main in %s --> %p", obj->path, (void *)*where)); 176 } 177 178 return 0; 179 } 180 181 caddr_t 182 _rtld_bind(const Obj_Entry *obj, Elf_Word reloff) 183 { 184 const Elf_Rel *rel = (const Elf_Rel *)((caddr_t)obj->pltrel + reloff); 185 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 186 Elf_Addr new_value; 187 const Elf_Sym *def; 188 const Obj_Entry *defobj; 189 190 assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JMP_SLOT)); 191 192 def = _rtld_find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true); 193 if (def == NULL) 194 _rtld_die(); 195 196 new_value = (Elf_Addr)(defobj->relocbase + def->st_value); 197 rdbg(("bind now/fixup in %s --> old=%p new=%p", 198 defobj->strtab + def->st_name, (void *)*where, (void *)new_value)); 199 if (*where != new_value) 200 *where = new_value; 201 202 return (caddr_t)new_value; 203 } 204 205 int 206 _rtld_relocate_plt_objects(const Obj_Entry *obj) 207 { 208 const Elf_Rel *rel; 209 210 for (rel = obj->pltrel; rel < obj->pltrellim; rel++) { 211 Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rel->r_offset); 212 Elf_Addr target; 213 const Elf_Sym *def; 214 const Obj_Entry *defobj; 215 216 assert(ELF_R_TYPE(rel->r_info) == R_TYPE(JMP_SLOT)); 217 218 def = _rtld_find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, 219 true); 220 if (def == NULL) 221 return -1; 222 target = (Elf_Addr)(defobj->relocbase + def->st_value); 223 rdbg(("bind now/fixup in %s --> old=%p new=%p", 224 defobj->strtab + def->st_name, (void *)*where, 225 (void *)target)); 226 if (*where != target) 227 *where = target; 228 } 229 return 0; 230 } 231
Indexes created Tue Sep 30 07:10:03 GMT 2025