| 1 | /* Intel 80386/80486-specific support for 32-bit ELF |
| 2 | Copyright 1993 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of BFD, the Binary File Descriptor library. |
| 5 | |
| 6 | This program is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 2 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | This program is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with this program; if not, write to the Free Software |
| 18 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ |
| 19 | |
| 20 | #include "bfd.h" |
| 21 | #include "sysdep.h" |
| 22 | #include "bfdlink.h" |
| 23 | #include "libbfd.h" |
| 24 | #include "libelf.h" |
| 25 | |
| 26 | static CONST struct reloc_howto_struct *elf_i386_reloc_type_lookup |
| 27 | PARAMS ((bfd *, bfd_reloc_code_real_type)); |
| 28 | static void elf_i386_info_to_howto |
| 29 | PARAMS ((bfd *, arelent *, Elf32_Internal_Rela *)); |
| 30 | static void elf_i386_info_to_howto_rel |
| 31 | PARAMS ((bfd *, arelent *, Elf32_Internal_Rel *)); |
| 32 | static boolean elf_i386_create_dynamic_sections |
| 33 | PARAMS ((bfd *, struct bfd_link_info *)); |
| 34 | static boolean elf_i386_adjust_dynamic_symbol |
| 35 | PARAMS ((struct bfd_link_info *, struct elf_link_hash_entry *)); |
| 36 | static boolean elf_i386_allocate_dynamic_section |
| 37 | PARAMS ((bfd *, const char *)); |
| 38 | static boolean elf_i386_size_dynamic_sections |
| 39 | PARAMS ((bfd *, struct bfd_link_info *)); |
| 40 | static boolean elf_i386_relocate_section |
| 41 | PARAMS ((bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *, |
| 42 | Elf_Internal_Rela *, Elf_Internal_Sym *, asection **)); |
| 43 | static boolean elf_i386_finish_dynamic_symbol |
| 44 | PARAMS ((bfd *, struct bfd_link_info *, struct elf_link_hash_entry *, |
| 45 | Elf_Internal_Sym *)); |
| 46 | static boolean elf_i386_finish_dynamic_sections |
| 47 | PARAMS ((bfd *, struct bfd_link_info *)); |
| 48 | |
| 49 | #define USE_REL 1 /* 386 uses REL relocations instead of RELA */ |
| 50 | |
| 51 | enum reloc_type |
| 52 | { |
| 53 | R_386_NONE = 0, |
| 54 | R_386_32, |
| 55 | R_386_PC32, |
| 56 | R_386_GOT32, |
| 57 | R_386_PLT32, |
| 58 | R_386_COPY, |
| 59 | R_386_GLOB_DAT, |
| 60 | R_386_JUMP_SLOT, |
| 61 | R_386_RELATIVE, |
| 62 | R_386_GOTOFF, |
| 63 | R_386_GOTPC, |
| 64 | R_386_max |
| 65 | }; |
| 66 | |
| 67 | #if 0 |
| 68 | static CONST char *CONST reloc_type_names[] = |
| 69 | { |
| 70 | "R_386_NONE", |
| 71 | "R_386_32", |
| 72 | "R_386_PC32", |
| 73 | "R_386_GOT32", |
| 74 | "R_386_PLT32", |
| 75 | "R_386_COPY", |
| 76 | "R_386_GLOB_DAT", |
| 77 | "R_386_JUMP_SLOT", |
| 78 | "R_386_RELATIVE", |
| 79 | "R_386_GOTOFF", |
| 80 | "R_386_GOTPC", |
| 81 | }; |
| 82 | #endif |
| 83 | |
| 84 | static reloc_howto_type elf_howto_table[]= |
| 85 | { |
| 86 | HOWTO(R_386_NONE, 0,0, 0,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_NONE", true,0x00000000,0x00000000,false), |
| 87 | HOWTO(R_386_32, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_32", true,0xffffffff,0xffffffff,false), |
| 88 | HOWTO(R_386_PC32, 0,2,32,true, 0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_PC32", true,0xffffffff,0xffffffff,true), |
| 89 | HOWTO(R_386_GOT32, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_GOT32", true,0xffffffff,0xffffffff,false), |
| 90 | HOWTO(R_386_PLT32, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_PLT32", true,0xffffffff,0xffffffff,false), |
| 91 | HOWTO(R_386_COPY, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_COPY", true,0xffffffff,0xffffffff,false), |
| 92 | HOWTO(R_386_GLOB_DAT, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_GLOB_DAT", true,0xffffffff,0xffffffff,false), |
| 93 | HOWTO(R_386_JUMP_SLOT, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_JUMP_SLOT",true,0xffffffff,0xffffffff,false), |
| 94 | HOWTO(R_386_RELATIVE, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_RELATIVE", true,0xffffffff,0xffffffff,false), |
| 95 | HOWTO(R_386_GOTOFF, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_GOTOFF", true,0xffffffff,0xffffffff,false), |
| 96 | HOWTO(R_386_GOTPC, 0,2,32,false,0,complain_overflow_bitfield, bfd_elf_generic_reloc,"R_386_GOTPC", true,0xffffffff,0xffffffff,false), |
| 97 | }; |
| 98 | |
| 99 | #ifdef DEBUG_GEN_RELOC |
| 100 | #define TRACE(str) fprintf (stderr, "i386 bfd reloc lookup %d (%s)\n", code, str) |
| 101 | #else |
| 102 | #define TRACE(str) |
| 103 | #endif |
| 104 | |
| 105 | static CONST struct reloc_howto_struct * |
| 106 | elf_i386_reloc_type_lookup (abfd, code) |
| 107 | bfd *abfd; |
| 108 | bfd_reloc_code_real_type code; |
| 109 | { |
| 110 | switch (code) |
| 111 | { |
| 112 | case BFD_RELOC_NONE: |
| 113 | TRACE ("BFD_RELOC_NONE"); |
| 114 | return &elf_howto_table[ (int)R_386_NONE ]; |
| 115 | |
| 116 | case BFD_RELOC_32: |
| 117 | TRACE ("BFD_RELOC_32"); |
| 118 | return &elf_howto_table[ (int)R_386_32 ]; |
| 119 | |
| 120 | case BFD_RELOC_32_PCREL: |
| 121 | TRACE ("BFD_RELOC_PC32"); |
| 122 | return &elf_howto_table[ (int)R_386_PC32 ]; |
| 123 | |
| 124 | case BFD_RELOC_386_GOT32: |
| 125 | TRACE ("BFD_RELOC_386_GOT32"); |
| 126 | return &elf_howto_table[ (int)R_386_GOT32 ]; |
| 127 | |
| 128 | case BFD_RELOC_386_PLT32: |
| 129 | TRACE ("BFD_RELOC_386_PLT32"); |
| 130 | return &elf_howto_table[ (int)R_386_PLT32 ]; |
| 131 | |
| 132 | case BFD_RELOC_386_COPY: |
| 133 | TRACE ("BFD_RELOC_386_COPY"); |
| 134 | return &elf_howto_table[ (int)R_386_COPY ]; |
| 135 | |
| 136 | case BFD_RELOC_386_GLOB_DAT: |
| 137 | TRACE ("BFD_RELOC_386_GLOB_DAT"); |
| 138 | return &elf_howto_table[ (int)R_386_GLOB_DAT ]; |
| 139 | |
| 140 | case BFD_RELOC_386_JUMP_SLOT: |
| 141 | TRACE ("BFD_RELOC_386_JUMP_SLOT"); |
| 142 | return &elf_howto_table[ (int)R_386_JUMP_SLOT ]; |
| 143 | |
| 144 | case BFD_RELOC_386_RELATIVE: |
| 145 | TRACE ("BFD_RELOC_386_RELATIVE"); |
| 146 | return &elf_howto_table[ (int)R_386_RELATIVE ]; |
| 147 | |
| 148 | case BFD_RELOC_386_GOTOFF: |
| 149 | TRACE ("BFD_RELOC_386_GOTOFF"); |
| 150 | return &elf_howto_table[ (int)R_386_GOTOFF ]; |
| 151 | |
| 152 | case BFD_RELOC_386_GOTPC: |
| 153 | TRACE ("BFD_RELOC_386_GOTPC"); |
| 154 | return &elf_howto_table[ (int)R_386_GOTPC ]; |
| 155 | |
| 156 | default: |
| 157 | break; |
| 158 | } |
| 159 | |
| 160 | TRACE ("Unknown"); |
| 161 | return 0; |
| 162 | } |
| 163 | |
| 164 | static void |
| 165 | elf_i386_info_to_howto (abfd, cache_ptr, dst) |
| 166 | bfd *abfd; |
| 167 | arelent *cache_ptr; |
| 168 | Elf32_Internal_Rela *dst; |
| 169 | { |
| 170 | BFD_ASSERT (ELF32_R_TYPE(dst->r_info) < (unsigned int) R_386_max); |
| 171 | |
| 172 | cache_ptr->howto = &elf_howto_table[ELF32_R_TYPE(dst->r_info)]; |
| 173 | } |
| 174 | |
| 175 | static void |
| 176 | elf_i386_info_to_howto_rel (abfd, cache_ptr, dst) |
| 177 | bfd *abfd; |
| 178 | arelent *cache_ptr; |
| 179 | Elf32_Internal_Rel *dst; |
| 180 | { |
| 181 | BFD_ASSERT (ELF32_R_TYPE(dst->r_info) < (unsigned int) R_386_max); |
| 182 | |
| 183 | cache_ptr->howto = &elf_howto_table[ELF32_R_TYPE(dst->r_info)]; |
| 184 | } |
| 185 | \f |
| 186 | /* Functions for the i386 ELF linker. */ |
| 187 | |
| 188 | /* The name of the dynamic interpreter. This is put in the .interp |
| 189 | section. */ |
| 190 | |
| 191 | #define ELF_DYNAMIC_INTERPRETER "/usr/lib/libc.so.1" |
| 192 | |
| 193 | /* The size in bytes of an entry in the procedure linkage table. */ |
| 194 | |
| 195 | #define PLT_ENTRY_SIZE 16 |
| 196 | |
| 197 | /* The first entry in an absolute procedure linkage table looks like |
| 198 | this. See the SVR4 ABI i386 supplement to see how this works. */ |
| 199 | |
| 200 | static bfd_byte elf_i386_plt0_entry[PLT_ENTRY_SIZE] = |
| 201 | { |
| 202 | 0xff, 0x35, /* pushl contents of address */ |
| 203 | 0, 0, 0, 0, /* replaced with address of .got + 4. */ |
| 204 | 0xff, 0x25, /* jmp indirect */ |
| 205 | 0, 0, 0, 0, /* replaced with address of .got + 8. */ |
| 206 | 0, 0, 0, 0 /* pad out to 16 bytes. */ |
| 207 | }; |
| 208 | |
| 209 | /* Subsequent entries in an absolute procedure linkage table look like |
| 210 | this. */ |
| 211 | |
| 212 | static bfd_byte elf_i386_plt_entry[PLT_ENTRY_SIZE] = |
| 213 | { |
| 214 | 0xff, 0x25, /* jmp indirect */ |
| 215 | 0, 0, 0, 0, /* replaced with address of this symbol in .got. */ |
| 216 | 0x68, /* pushl immediate */ |
| 217 | 0, 0, 0, 0, /* replaced with offset into relocation table. */ |
| 218 | 0xe9, /* jmp relative */ |
| 219 | 0, 0, 0, 0 /* replaced with offset to start of .plt. */ |
| 220 | }; |
| 221 | |
| 222 | /* Create dynamic sections when linking against a dynamic object. */ |
| 223 | |
| 224 | static boolean |
| 225 | elf_i386_create_dynamic_sections (abfd, info) |
| 226 | bfd *abfd; |
| 227 | struct bfd_link_info *info; |
| 228 | { |
| 229 | flagword flags; |
| 230 | register asection *s; |
| 231 | struct elf_link_hash_entry *h; |
| 232 | |
| 233 | /* We need to create .plt, .rel.plt, .got, .dynbss, and .rel.bss |
| 234 | sections. */ |
| 235 | |
| 236 | flags = SEC_ALLOC | SEC_LOAD | SEC_HAS_CONTENTS | SEC_IN_MEMORY; |
| 237 | |
| 238 | s = bfd_make_section (abfd, ".plt"); |
| 239 | if (s == NULL |
| 240 | || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY | SEC_CODE) |
| 241 | || ! bfd_set_section_alignment (abfd, s, 2)) |
| 242 | return false; |
| 243 | |
| 244 | s = bfd_make_section (abfd, ".rel.plt"); |
| 245 | if (s == NULL |
| 246 | || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY) |
| 247 | || ! bfd_set_section_alignment (abfd, s, 2)) |
| 248 | return false; |
| 249 | |
| 250 | s = bfd_make_section (abfd, ".got"); |
| 251 | if (s == NULL |
| 252 | || ! bfd_set_section_flags (abfd, s, flags) |
| 253 | || ! bfd_set_section_alignment (abfd, s, 2)) |
| 254 | return false; |
| 255 | |
| 256 | /* Define the symbol _GLOBAL_OFFSET_TABLE_ at the start of the .got |
| 257 | section. We don't do this in the linker script because we don't |
| 258 | want to define the symbol if we are not creating a global offset |
| 259 | table. */ |
| 260 | h = NULL; |
| 261 | if (! (_bfd_generic_link_add_one_symbol |
| 262 | (info, abfd, "_GLOBAL_OFFSET_TABLE_", BSF_GLOBAL, s, (bfd_vma) 0, |
| 263 | (const char *) NULL, false, get_elf_backend_data (abfd)->collect, |
| 264 | (struct bfd_link_hash_entry **) &h))) |
| 265 | return false; |
| 266 | h->elf_link_hash_flags |= ELF_LINK_HASH_DEF_REGULAR; |
| 267 | |
| 268 | /* The first three global offset table entries are reserved. */ |
| 269 | s->_raw_size += 3 * 4; |
| 270 | |
| 271 | /* The .dynbss section is a place to put symbols which are defined |
| 272 | by dynamic objects, are referenced by regular objects, and are |
| 273 | not functions. We must allocate space for them in the process |
| 274 | image and use a R_386_COPY reloc to tell the dynamic linker to |
| 275 | initialize them at run time. The linker script puts the .dynbss |
| 276 | section into the .bss section of the final image. */ |
| 277 | s = bfd_make_section (abfd, ".dynbss"); |
| 278 | if (s == NULL |
| 279 | || ! bfd_set_section_flags (abfd, s, SEC_ALLOC)) |
| 280 | return false; |
| 281 | |
| 282 | /* The .rel.bss section holds copy relocs. This section is not |
| 283 | normally needed. We need to create it here, though, so that the |
| 284 | linker will map it to an output section. If it turns out not to |
| 285 | be needed, we can discard it later. */ |
| 286 | s = bfd_make_section (abfd, ".rel.bss"); |
| 287 | if (s == NULL |
| 288 | || ! bfd_set_section_flags (abfd, s, flags | SEC_READONLY) |
| 289 | || ! bfd_set_section_alignment (abfd, s, 2)) |
| 290 | return false; |
| 291 | |
| 292 | return true; |
| 293 | } |
| 294 | |
| 295 | /* Adjust a symbol defined by a dynamic object and referenced by a |
| 296 | regular object. The current definition is in some section of the |
| 297 | dynamic object, but we're not including those sections. We have to |
| 298 | change the definition to something the rest of the link can |
| 299 | understand. */ |
| 300 | |
| 301 | static boolean |
| 302 | elf_i386_adjust_dynamic_symbol (info, h) |
| 303 | struct bfd_link_info *info; |
| 304 | struct elf_link_hash_entry *h; |
| 305 | { |
| 306 | bfd *dynobj; |
| 307 | asection *s; |
| 308 | unsigned int power_of_two; |
| 309 | size_t align; |
| 310 | |
| 311 | dynobj = elf_hash_table (info)->dynobj; |
| 312 | |
| 313 | /* Make sure we know what is going on here. */ |
| 314 | BFD_ASSERT (dynobj != NULL |
| 315 | && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) != 0 |
| 316 | && (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) != 0 |
| 317 | && (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) == 0 |
| 318 | && h->root.type == bfd_link_hash_defined |
| 319 | && (bfd_get_flavour (h->root.u.def.section->owner) |
| 320 | == bfd_target_elf_flavour) |
| 321 | && (elf_elfheader (h->root.u.def.section->owner)->e_type |
| 322 | == ET_DYN) |
| 323 | && h->root.u.def.section->output_section == NULL); |
| 324 | |
| 325 | /* If this is a function, put it in the procedure linkage table. We |
| 326 | will fill in the contents of the procedure linkage table later, |
| 327 | when we know the address of the .got section. */ |
| 328 | if (h->type == STT_FUNC) |
| 329 | { |
| 330 | s = bfd_get_section_by_name (dynobj, ".plt"); |
| 331 | BFD_ASSERT (s != NULL); |
| 332 | |
| 333 | /* If this is the first .plt entry, make room for the special |
| 334 | first entry. */ |
| 335 | if (s->_raw_size == 0) |
| 336 | s->_raw_size += PLT_ENTRY_SIZE; |
| 337 | |
| 338 | /* Set the symbol to this location in the .plt. */ |
| 339 | h->root.u.def.section = s; |
| 340 | h->root.u.def.value = s->_raw_size; |
| 341 | |
| 342 | /* Make room for this entry. */ |
| 343 | s->_raw_size += PLT_ENTRY_SIZE; |
| 344 | |
| 345 | /* We also need to make an entry in the .got section. */ |
| 346 | |
| 347 | s = bfd_get_section_by_name (dynobj, ".got"); |
| 348 | BFD_ASSERT (s != NULL); |
| 349 | s->_raw_size += 4; |
| 350 | |
| 351 | /* We also need to make an entry in the .rel.plt section. */ |
| 352 | |
| 353 | s = bfd_get_section_by_name (dynobj, ".rel.plt"); |
| 354 | BFD_ASSERT (s != NULL); |
| 355 | s->_raw_size += sizeof (Elf32_External_Rel); |
| 356 | |
| 357 | return true; |
| 358 | } |
| 359 | |
| 360 | /* If this is a weak symbol, and there is a real definition, the |
| 361 | processor independent code will have arranged for us to see the |
| 362 | real definition first, and we can just use the same value. */ |
| 363 | if (h->weakdef != NULL) |
| 364 | { |
| 365 | BFD_ASSERT (h->weakdef->root.type == bfd_link_hash_defined); |
| 366 | h->root.u.def.section = h->weakdef->root.u.def.section; |
| 367 | h->root.u.def.value = h->weakdef->root.u.def.value; |
| 368 | h->align = (bfd_size_type) -1; |
| 369 | return true; |
| 370 | } |
| 371 | |
| 372 | /* This is a reference to a symbol defined by a dynamic object which |
| 373 | is not a function. We must allocate it in our .dynbss section, |
| 374 | which will become part of the .bss section of the executable. |
| 375 | There will be an entry for this symbol in the .dynsym section. |
| 376 | The dynamic object will contain position independent code, so all |
| 377 | references from the dynamic object to this symbol will go through |
| 378 | the global offset table. The dynamic linker will use the .dynsym |
| 379 | entry to determine the address it must put in the global offset |
| 380 | table, so both the dynamic object and the regular object will |
| 381 | refer to the same memory location for the variable. */ |
| 382 | |
| 383 | s = bfd_get_section_by_name (dynobj, ".dynbss"); |
| 384 | BFD_ASSERT (s != NULL); |
| 385 | |
| 386 | /* If the symbol is currently defined in the .bss section of the |
| 387 | dynamic object, then it is OK to simply initialize it to zero. |
| 388 | If the symbol is in some other section, we must generate a |
| 389 | R_386_COPY reloc to tell the dynamic linker to copy the initial |
| 390 | value out of the dynamic object and into the runtime process |
| 391 | image. We need to remember the offset into the .rel.bss section |
| 392 | we are going to use, and we coopt the align field for this |
| 393 | purpose (the align field is only used for common symbols, and |
| 394 | these symbols are always defined). It would be cleaner to use a |
| 395 | new field, but that would waste memory. */ |
| 396 | if ((h->root.u.def.section->flags & SEC_LOAD) == 0) |
| 397 | h->align = (bfd_size_type) -1; |
| 398 | else |
| 399 | { |
| 400 | asection *srel; |
| 401 | |
| 402 | srel = bfd_get_section_by_name (dynobj, ".rel.bss"); |
| 403 | BFD_ASSERT (srel != NULL); |
| 404 | h->align = srel->_raw_size; |
| 405 | srel->_raw_size += sizeof (Elf32_External_Rel); |
| 406 | } |
| 407 | |
| 408 | /* We need to figure out the alignment required for this symbol. I |
| 409 | have no idea how ELF linkers handle this. */ |
| 410 | switch (h->size) |
| 411 | { |
| 412 | case 0: |
| 413 | case 1: |
| 414 | power_of_two = 0; |
| 415 | align = 1; |
| 416 | break; |
| 417 | case 2: |
| 418 | power_of_two = 1; |
| 419 | align = 2; |
| 420 | break; |
| 421 | case 3: |
| 422 | case 4: |
| 423 | power_of_two = 2; |
| 424 | align = 4; |
| 425 | break; |
| 426 | case 5: |
| 427 | case 6: |
| 428 | case 7: |
| 429 | case 8: |
| 430 | power_of_two = 3; |
| 431 | align = 8; |
| 432 | break; |
| 433 | default: |
| 434 | power_of_two = 4; |
| 435 | align = 16; |
| 436 | break; |
| 437 | } |
| 438 | |
| 439 | /* Apply the required alignment. */ |
| 440 | s->_raw_size = BFD_ALIGN (s->_raw_size, align); |
| 441 | if (power_of_two > bfd_get_section_alignment (dynobj, s)) |
| 442 | { |
| 443 | if (! bfd_set_section_alignment (dynobj, s, power_of_two)) |
| 444 | return false; |
| 445 | } |
| 446 | |
| 447 | /* Define the symbol as being at this point in the section. */ |
| 448 | h->root.u.def.section = s; |
| 449 | h->root.u.def.value = s->_raw_size; |
| 450 | |
| 451 | /* Increment the section size to make room for the symbol. */ |
| 452 | s->_raw_size += h->size; |
| 453 | |
| 454 | return true; |
| 455 | } |
| 456 | |
| 457 | /* Allocate contents for a section. */ |
| 458 | |
| 459 | static INLINE boolean |
| 460 | elf_i386_allocate_dynamic_section (dynobj, name) |
| 461 | bfd *dynobj; |
| 462 | const char *name; |
| 463 | { |
| 464 | register asection *s; |
| 465 | |
| 466 | s = bfd_get_section_by_name (dynobj, name); |
| 467 | BFD_ASSERT (s != NULL); |
| 468 | s->contents = (bfd_byte *) bfd_alloc (dynobj, s->_raw_size); |
| 469 | if (s->contents == NULL && s->_raw_size != 0) |
| 470 | { |
| 471 | bfd_set_error (bfd_error_no_memory); |
| 472 | return false; |
| 473 | } |
| 474 | return true; |
| 475 | } |
| 476 | |
| 477 | /* Set the sizes of the dynamic sections. */ |
| 478 | |
| 479 | static boolean |
| 480 | elf_i386_size_dynamic_sections (output_bfd, info) |
| 481 | bfd *output_bfd; |
| 482 | struct bfd_link_info *info; |
| 483 | { |
| 484 | bfd *dynobj; |
| 485 | asection *s; |
| 486 | |
| 487 | dynobj = elf_hash_table (info)->dynobj; |
| 488 | BFD_ASSERT (dynobj != NULL); |
| 489 | |
| 490 | /* Set the contents of the .interp section to the interpreter. */ |
| 491 | if (! info->shared) |
| 492 | { |
| 493 | s = bfd_get_section_by_name (dynobj, ".interp"); |
| 494 | BFD_ASSERT (s != NULL); |
| 495 | s->_raw_size = sizeof ELF_DYNAMIC_INTERPRETER; |
| 496 | s->contents = (unsigned char *) ELF_DYNAMIC_INTERPRETER; |
| 497 | } |
| 498 | |
| 499 | /* The adjust_dynamic_symbol entry point has determined the sizes of |
| 500 | the various dynamic sections. Allocate some memory for them to |
| 501 | hold contents. */ |
| 502 | if (! elf_i386_allocate_dynamic_section (dynobj, ".plt") |
| 503 | || ! elf_i386_allocate_dynamic_section (dynobj, ".rel.plt") |
| 504 | || ! elf_i386_allocate_dynamic_section (dynobj, ".got") |
| 505 | || ! elf_i386_allocate_dynamic_section (dynobj, ".rel.bss")) |
| 506 | return false; |
| 507 | |
| 508 | /* Add some entries to the .dynamic section. We fill in the values |
| 509 | later, in elf_i386_finish_dynamic_sections, but we must add the |
| 510 | entries now so that we get the correct size for the .dynamic |
| 511 | section. The DT_DEBUG entry is filled in by the dynamic linker |
| 512 | and used by the debugger. */ |
| 513 | if (! bfd_elf32_add_dynamic_entry (info, DT_DEBUG, 0) |
| 514 | || ! bfd_elf32_add_dynamic_entry (info, DT_PLTGOT, 0)) |
| 515 | return false; |
| 516 | |
| 517 | s = bfd_get_section_by_name (dynobj, ".plt"); |
| 518 | BFD_ASSERT (s != NULL); |
| 519 | if (s->_raw_size != 0) |
| 520 | { |
| 521 | if (! bfd_elf32_add_dynamic_entry (info, DT_PLTRELSZ, 0) |
| 522 | || ! bfd_elf32_add_dynamic_entry (info, DT_PLTREL, DT_REL) |
| 523 | || ! bfd_elf32_add_dynamic_entry (info, DT_JMPREL, 0)) |
| 524 | return false; |
| 525 | } |
| 526 | |
| 527 | /* If we didn't need the .rel.bss section, then discard it from the |
| 528 | output file. This is a hack. We don't bother to do it for the |
| 529 | other sections because they normally are needed. */ |
| 530 | s = bfd_get_section_by_name (dynobj, ".rel.bss"); |
| 531 | BFD_ASSERT (s != NULL); |
| 532 | if (s->_raw_size == 0) |
| 533 | { |
| 534 | asection **spp; |
| 535 | |
| 536 | for (spp = &s->output_section->owner->sections; |
| 537 | *spp != s->output_section; |
| 538 | spp = &(*spp)->next) |
| 539 | ; |
| 540 | *spp = s->output_section->next; |
| 541 | --s->output_section->owner->section_count; |
| 542 | } |
| 543 | else |
| 544 | { |
| 545 | if (! bfd_elf32_add_dynamic_entry (info, DT_REL, 0) |
| 546 | || ! bfd_elf32_add_dynamic_entry (info, DT_RELSZ, 0) |
| 547 | || ! bfd_elf32_add_dynamic_entry (info, DT_RELENT, |
| 548 | sizeof (Elf32_External_Rel))) |
| 549 | return false; |
| 550 | } |
| 551 | |
| 552 | return true; |
| 553 | } |
| 554 | |
| 555 | /* Relocate an i386 ELF section. */ |
| 556 | |
| 557 | static boolean |
| 558 | elf_i386_relocate_section (output_bfd, info, input_bfd, input_section, |
| 559 | contents, relocs, local_syms, local_sections) |
| 560 | bfd *output_bfd; |
| 561 | struct bfd_link_info *info; |
| 562 | bfd *input_bfd; |
| 563 | asection *input_section; |
| 564 | bfd_byte *contents; |
| 565 | Elf_Internal_Rela *relocs; |
| 566 | Elf_Internal_Sym *local_syms; |
| 567 | asection **local_sections; |
| 568 | { |
| 569 | Elf_Internal_Shdr *symtab_hdr; |
| 570 | Elf_Internal_Rela *rel; |
| 571 | Elf_Internal_Rela *relend; |
| 572 | |
| 573 | symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr; |
| 574 | |
| 575 | rel = relocs; |
| 576 | relend = relocs + input_section->reloc_count; |
| 577 | for (; rel < relend; rel++) |
| 578 | { |
| 579 | int r_type; |
| 580 | const reloc_howto_type *howto; |
| 581 | long r_symndx; |
| 582 | struct elf_link_hash_entry *h; |
| 583 | Elf_Internal_Sym *sym; |
| 584 | asection *sec; |
| 585 | bfd_vma relocation; |
| 586 | bfd_reloc_status_type r; |
| 587 | |
| 588 | r_type = ELF32_R_TYPE (rel->r_info); |
| 589 | if (r_type < 0 || r_type >= (int) R_386_max) |
| 590 | { |
| 591 | bfd_set_error (bfd_error_bad_value); |
| 592 | return false; |
| 593 | } |
| 594 | howto = elf_howto_table + r_type; |
| 595 | |
| 596 | r_symndx = ELF32_R_SYM (rel->r_info); |
| 597 | |
| 598 | if (info->relocateable) |
| 599 | { |
| 600 | /* This is a relocateable link. We don't have to change |
| 601 | anything, unless the reloc is against a section symbol, |
| 602 | in which case we have to adjust according to where the |
| 603 | section symbol winds up in the output section. */ |
| 604 | if (r_symndx < symtab_hdr->sh_info) |
| 605 | { |
| 606 | sym = local_syms + r_symndx; |
| 607 | if (ELF_ST_TYPE (sym->st_info) == STT_SECTION) |
| 608 | { |
| 609 | bfd_vma val; |
| 610 | |
| 611 | sec = local_sections[r_symndx]; |
| 612 | val = bfd_get_32 (input_bfd, contents + rel->r_offset); |
| 613 | val += sec->output_offset + sym->st_value; |
| 614 | bfd_put_32 (input_bfd, val, contents + rel->r_offset); |
| 615 | } |
| 616 | } |
| 617 | |
| 618 | continue; |
| 619 | } |
| 620 | |
| 621 | /* This is a final link. */ |
| 622 | h = NULL; |
| 623 | sym = NULL; |
| 624 | sec = NULL; |
| 625 | if (r_symndx < symtab_hdr->sh_info) |
| 626 | { |
| 627 | sym = local_syms + r_symndx; |
| 628 | sec = local_sections[r_symndx]; |
| 629 | relocation = (sec->output_section->vma |
| 630 | + sec->output_offset |
| 631 | + sym->st_value); |
| 632 | } |
| 633 | else |
| 634 | { |
| 635 | long indx; |
| 636 | |
| 637 | indx = r_symndx - symtab_hdr->sh_info; |
| 638 | h = elf_sym_hashes (input_bfd)[indx]; |
| 639 | if (h->root.type == bfd_link_hash_defined) |
| 640 | { |
| 641 | sec = h->root.u.def.section; |
| 642 | relocation = (h->root.u.def.value |
| 643 | + sec->output_section->vma |
| 644 | + sec->output_offset); |
| 645 | } |
| 646 | else if (h->root.type == bfd_link_hash_weak) |
| 647 | relocation = 0; |
| 648 | else |
| 649 | { |
| 650 | if (! ((*info->callbacks->undefined_symbol) |
| 651 | (info, h->root.root.string, input_bfd, |
| 652 | input_section, rel->r_offset))) |
| 653 | return false; |
| 654 | relocation = 0; |
| 655 | } |
| 656 | } |
| 657 | |
| 658 | r = _bfd_final_link_relocate (howto, input_bfd, input_section, |
| 659 | contents, rel->r_offset, |
| 660 | relocation, (bfd_vma) 0); |
| 661 | |
| 662 | if (r != bfd_reloc_ok) |
| 663 | { |
| 664 | switch (r) |
| 665 | { |
| 666 | default: |
| 667 | case bfd_reloc_outofrange: |
| 668 | abort (); |
| 669 | case bfd_reloc_overflow: |
| 670 | { |
| 671 | const char *name; |
| 672 | |
| 673 | if (h != NULL) |
| 674 | name = h->root.root.string; |
| 675 | else |
| 676 | { |
| 677 | name = elf_string_from_elf_section (input_bfd, |
| 678 | symtab_hdr->sh_link, |
| 679 | sym->st_name); |
| 680 | if (name == NULL) |
| 681 | return false; |
| 682 | if (*name == '\0') |
| 683 | name = bfd_section_name (input_bfd, sec); |
| 684 | } |
| 685 | if (! ((*info->callbacks->reloc_overflow) |
| 686 | (info, name, howto->name, (bfd_vma) 0, |
| 687 | input_bfd, input_section, rel->r_offset))) |
| 688 | return false; |
| 689 | } |
| 690 | break; |
| 691 | } |
| 692 | } |
| 693 | } |
| 694 | |
| 695 | return true; |
| 696 | } |
| 697 | |
| 698 | /* Finish up dynamic symbol handling. We set the contents of various |
| 699 | dynamic sections here. */ |
| 700 | |
| 701 | static boolean |
| 702 | elf_i386_finish_dynamic_symbol (output_bfd, info, h, sym) |
| 703 | bfd *output_bfd; |
| 704 | struct bfd_link_info *info; |
| 705 | struct elf_link_hash_entry *h; |
| 706 | Elf_Internal_Sym *sym; |
| 707 | { |
| 708 | /* If this symbol is not defined by a dynamic object, or is not |
| 709 | referenced by a regular object, ignore it. */ |
| 710 | if ((h->elf_link_hash_flags & ELF_LINK_HASH_DEF_REGULAR) != 0 |
| 711 | || (h->elf_link_hash_flags & ELF_LINK_HASH_DEF_DYNAMIC) == 0 |
| 712 | || (h->elf_link_hash_flags & ELF_LINK_HASH_REF_REGULAR) == 0) |
| 713 | { |
| 714 | /* Mark _DYNAMIC and _GLOBAL_OFFSET_TABLE_ as absolute. */ |
| 715 | if (strcmp (h->root.root.string, "_DYNAMIC") == 0 |
| 716 | || strcmp (h->root.root.string, "_GLOBAL_OFFSET_TABLE_") == 0) |
| 717 | sym->st_shndx = SHN_ABS; |
| 718 | return true; |
| 719 | } |
| 720 | |
| 721 | BFD_ASSERT (h->root.type == bfd_link_hash_defined); |
| 722 | BFD_ASSERT (h->dynindx != -1); |
| 723 | |
| 724 | if (h->type == STT_FUNC) |
| 725 | { |
| 726 | asection *splt; |
| 727 | asection *sgot; |
| 728 | asection *srel; |
| 729 | bfd_vma plt_index; |
| 730 | bfd_vma got_offset; |
| 731 | Elf_Internal_Rel rel; |
| 732 | |
| 733 | splt = h->root.u.def.section; |
| 734 | BFD_ASSERT (strcmp (bfd_get_section_name (splt->owner, splt), ".plt") |
| 735 | == 0); |
| 736 | sgot = bfd_get_section_by_name (splt->owner, ".got"); |
| 737 | BFD_ASSERT (sgot != NULL); |
| 738 | srel = bfd_get_section_by_name (splt->owner, ".rel.plt"); |
| 739 | BFD_ASSERT (srel != NULL); |
| 740 | |
| 741 | /* FIXME: This only handles an absolute procedure linkage table. |
| 742 | When producing a dynamic object, we need to generate a |
| 743 | position independent procedure linkage table. */ |
| 744 | |
| 745 | /* Get the index in the procedure linkage table which |
| 746 | corresponds to this symbol. This is the index of this symbol |
| 747 | in all the symbols for which we are making plt entries. The |
| 748 | first entry in the procedure linkage table is reserved. */ |
| 749 | plt_index = h->root.u.def.value / PLT_ENTRY_SIZE - 1; |
| 750 | |
| 751 | /* Get the offset into the .got table of the entry that |
| 752 | corresponds to this function. Each .got entry is 4 bytes. |
| 753 | The first three are reserved. */ |
| 754 | got_offset = (plt_index + 3) * 4; |
| 755 | |
| 756 | /* Fill in the entry in the procedure linkage table. */ |
| 757 | memcpy (splt->contents + h->root.u.def.value, elf_i386_plt_entry, |
| 758 | PLT_ENTRY_SIZE); |
| 759 | bfd_put_32 (output_bfd, |
| 760 | (sgot->output_section->vma |
| 761 | + sgot->output_offset |
| 762 | + got_offset), |
| 763 | splt->contents + h->root.u.def.value + 2); |
| 764 | bfd_put_32 (output_bfd, plt_index * sizeof (Elf32_External_Rel), |
| 765 | splt->contents + h->root.u.def.value + 7); |
| 766 | bfd_put_32 (output_bfd, - (h->root.u.def.value + PLT_ENTRY_SIZE), |
| 767 | splt->contents + h->root.u.def.value + 12); |
| 768 | |
| 769 | /* Fill in the entry in the global offset table. */ |
| 770 | bfd_put_32 (output_bfd, |
| 771 | (splt->output_section->vma |
| 772 | + splt->output_offset |
| 773 | + h->root.u.def.value |
| 774 | + 6), |
| 775 | sgot->contents + got_offset); |
| 776 | |
| 777 | /* Fill in the entry in the .rel.plt section. */ |
| 778 | rel.r_offset = (sgot->output_section->vma |
| 779 | + sgot->output_offset |
| 780 | + got_offset); |
| 781 | rel.r_info = ELF32_R_INFO (h->dynindx, R_386_JUMP_SLOT); |
| 782 | bfd_elf32_swap_reloc_out (output_bfd, &rel, |
| 783 | ((Elf32_External_Rel *) srel->contents |
| 784 | + plt_index)); |
| 785 | |
| 786 | /* Mark the symbol as undefined, rather than as defined in the |
| 787 | .plt section. Leave the value alone. */ |
| 788 | sym->st_shndx = SHN_UNDEF; |
| 789 | } |
| 790 | else |
| 791 | { |
| 792 | /* This is not a function. We have already allocated memory for |
| 793 | it in the .bss section (via .dynbss). All we have to do here |
| 794 | is create a COPY reloc if required. */ |
| 795 | if (h->align != (bfd_size_type) -1) |
| 796 | { |
| 797 | asection *s; |
| 798 | Elf_Internal_Rel rel; |
| 799 | |
| 800 | s = bfd_get_section_by_name (h->root.u.def.section->owner, |
| 801 | ".rel.bss"); |
| 802 | BFD_ASSERT (s != NULL); |
| 803 | |
| 804 | rel.r_offset = (h->root.u.def.value |
| 805 | + h->root.u.def.section->output_section->vma |
| 806 | + h->root.u.def.section->output_offset); |
| 807 | rel.r_info = ELF32_R_INFO (h->dynindx, R_386_COPY); |
| 808 | bfd_elf32_swap_reloc_out (output_bfd, &rel, |
| 809 | ((Elf32_External_Rel *) |
| 810 | (s->contents + h->align))); |
| 811 | } |
| 812 | } |
| 813 | |
| 814 | return true; |
| 815 | } |
| 816 | |
| 817 | /* Finish up the dynamic sections. */ |
| 818 | |
| 819 | static boolean |
| 820 | elf_i386_finish_dynamic_sections (output_bfd, info) |
| 821 | bfd *output_bfd; |
| 822 | struct bfd_link_info *info; |
| 823 | { |
| 824 | asection *splt; |
| 825 | asection *sgot; |
| 826 | asection *sdyn; |
| 827 | Elf32_External_Dyn *dyncon, *dynconend; |
| 828 | |
| 829 | splt = bfd_get_section_by_name (elf_hash_table (info)->dynobj, ".plt"); |
| 830 | sgot = bfd_get_section_by_name (elf_hash_table (info)->dynobj, ".got"); |
| 831 | sdyn = bfd_get_section_by_name (elf_hash_table (info)->dynobj, ".dynamic"); |
| 832 | BFD_ASSERT (splt != NULL && sgot != NULL && sdyn != NULL); |
| 833 | |
| 834 | dyncon = (Elf32_External_Dyn *) sdyn->contents; |
| 835 | dynconend = (Elf32_External_Dyn *) (sdyn->contents + sdyn->_raw_size); |
| 836 | for (; dyncon < dynconend; dyncon++) |
| 837 | { |
| 838 | Elf_Internal_Dyn dyn; |
| 839 | const char *name; |
| 840 | boolean size; |
| 841 | |
| 842 | bfd_elf32_swap_dyn_in (elf_hash_table (info)->dynobj, dyncon, &dyn); |
| 843 | |
| 844 | /* My reading of the SVR4 ABI indicates that the procedure |
| 845 | linkage table relocs (DT_JMPREL) should be included in the |
| 846 | overall relocs (DT_REL). This is what Solaris does. |
| 847 | However, UnixWare can not handle that case. Therefore, we |
| 848 | override the DT_REL and DT_RELSZ entries here to make them |
| 849 | not include the JMPREL relocs. */ |
| 850 | |
| 851 | switch (dyn.d_tag) |
| 852 | { |
| 853 | case DT_PLTGOT: name = ".got"; size = false; break; |
| 854 | case DT_PLTRELSZ: name = ".rel.plt"; size = true; break; |
| 855 | case DT_JMPREL: name = ".rel.plt"; size = false; break; |
| 856 | case DT_REL: name = ".rel.bss"; size = false; break; |
| 857 | case DT_RELSZ: name = ".rel.bss"; size = true; break; |
| 858 | default: name = NULL; size = false; break; |
| 859 | } |
| 860 | |
| 861 | if (name != NULL) |
| 862 | { |
| 863 | asection *s; |
| 864 | |
| 865 | s = bfd_get_section_by_name (output_bfd, name); |
| 866 | BFD_ASSERT (s != NULL); |
| 867 | if (! size) |
| 868 | dyn.d_un.d_ptr = s->vma; |
| 869 | else |
| 870 | { |
| 871 | if (s->_cooked_size != 0) |
| 872 | dyn.d_un.d_val = s->_cooked_size; |
| 873 | else |
| 874 | dyn.d_un.d_val = s->_raw_size; |
| 875 | } |
| 876 | bfd_elf32_swap_dyn_out (output_bfd, &dyn, dyncon); |
| 877 | } |
| 878 | } |
| 879 | |
| 880 | /* Fill in the first entry in the procedure linkage table. */ |
| 881 | if (splt->_raw_size > 0) |
| 882 | { |
| 883 | memcpy (splt->contents, elf_i386_plt0_entry, PLT_ENTRY_SIZE); |
| 884 | bfd_put_32 (output_bfd, |
| 885 | sgot->output_section->vma + sgot->output_offset + 4, |
| 886 | splt->contents + 2); |
| 887 | bfd_put_32 (output_bfd, |
| 888 | sgot->output_section->vma + sgot->output_offset + 8, |
| 889 | splt->contents + 8); |
| 890 | } |
| 891 | |
| 892 | /* Fill in the first three entries in the global offset table. */ |
| 893 | if (sgot->_raw_size > 0) |
| 894 | { |
| 895 | bfd_put_32 (output_bfd, |
| 896 | sdyn->output_section->vma + sdyn->output_offset, |
| 897 | sgot->contents); |
| 898 | bfd_put_32 (output_bfd, (bfd_vma) 0, sgot->contents + 4); |
| 899 | bfd_put_32 (output_bfd, (bfd_vma) 0, sgot->contents + 8); |
| 900 | } |
| 901 | |
| 902 | elf_section_data (sgot->output_section)->this_hdr.sh_entsize = 4; |
| 903 | |
| 904 | /* UnixWare sets the entsize of .plt to 4, although that doesn't |
| 905 | really seem like the right value. */ |
| 906 | elf_section_data (splt->output_section)->this_hdr.sh_entsize = 4; |
| 907 | |
| 908 | return true; |
| 909 | } |
| 910 | |
| 911 | #define TARGET_LITTLE_SYM bfd_elf32_i386_vec |
| 912 | #define TARGET_LITTLE_NAME "elf32-i386" |
| 913 | #define ELF_ARCH bfd_arch_i386 |
| 914 | #define ELF_MACHINE_CODE EM_386 |
| 915 | #define elf_info_to_howto elf_i386_info_to_howto |
| 916 | #define elf_info_to_howto_rel elf_i386_info_to_howto_rel |
| 917 | #define bfd_elf32_bfd_reloc_type_lookup elf_i386_reloc_type_lookup |
| 918 | #define ELF_MAXPAGESIZE 0x1000 |
| 919 | #define elf_backend_create_dynamic_sections \ |
| 920 | elf_i386_create_dynamic_sections |
| 921 | #define elf_backend_adjust_dynamic_symbol \ |
| 922 | elf_i386_adjust_dynamic_symbol |
| 923 | #define elf_backend_size_dynamic_sections \ |
| 924 | elf_i386_size_dynamic_sections |
| 925 | #define elf_backend_relocate_section elf_i386_relocate_section |
| 926 | #define elf_backend_finish_dynamic_symbol \ |
| 927 | elf_i386_finish_dynamic_symbol |
| 928 | #define elf_backend_finish_dynamic_sections \ |
| 929 | elf_i386_finish_dynamic_sections |
| 930 | |
| 931 | #include "elf32-target.h" |