1 // Copyright 2010 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package ld 6 7 import ( 8 "cmd/internal/obj" 9 "encoding/binary" 10 "fmt" 11 "log" 12 "sort" 13 "strings" 14 ) 15 16 const ( 17 IMAGE_SYM_UNDEFINED = 0 18 IMAGE_SYM_ABSOLUTE = -1 19 IMAGE_SYM_DEBUG = -2 20 IMAGE_SYM_TYPE_NULL = 0 21 IMAGE_SYM_TYPE_VOID = 1 22 IMAGE_SYM_TYPE_CHAR = 2 23 IMAGE_SYM_TYPE_SHORT = 3 24 IMAGE_SYM_TYPE_INT = 4 25 IMAGE_SYM_TYPE_LONG = 5 26 IMAGE_SYM_TYPE_FLOAT = 6 27 IMAGE_SYM_TYPE_DOUBLE = 7 28 IMAGE_SYM_TYPE_STRUCT = 8 29 IMAGE_SYM_TYPE_UNION = 9 30 IMAGE_SYM_TYPE_ENUM = 10 31 IMAGE_SYM_TYPE_MOE = 11 32 IMAGE_SYM_TYPE_BYTE = 12 33 IMAGE_SYM_TYPE_WORD = 13 34 IMAGE_SYM_TYPE_UINT = 14 35 IMAGE_SYM_TYPE_DWORD = 15 36 IMAGE_SYM_TYPE_PCODE = 32768 37 IMAGE_SYM_DTYPE_NULL = 0 38 IMAGE_SYM_DTYPE_POINTER = 0x10 39 IMAGE_SYM_DTYPE_FUNCTION = 0x20 40 IMAGE_SYM_DTYPE_ARRAY = 0x30 41 IMAGE_SYM_CLASS_END_OF_FUNCTION = -1 42 IMAGE_SYM_CLASS_NULL = 0 43 IMAGE_SYM_CLASS_AUTOMATIC = 1 44 IMAGE_SYM_CLASS_EXTERNAL = 2 45 IMAGE_SYM_CLASS_STATIC = 3 46 IMAGE_SYM_CLASS_REGISTER = 4 47 IMAGE_SYM_CLASS_EXTERNAL_DEF = 5 48 IMAGE_SYM_CLASS_LABEL = 6 49 IMAGE_SYM_CLASS_UNDEFINED_LABEL = 7 50 IMAGE_SYM_CLASS_MEMBER_OF_STRUCT = 8 51 IMAGE_SYM_CLASS_ARGUMENT = 9 52 IMAGE_SYM_CLASS_STRUCT_TAG = 10 53 IMAGE_SYM_CLASS_MEMBER_OF_UNION = 11 54 IMAGE_SYM_CLASS_UNION_TAG = 12 55 IMAGE_SYM_CLASS_TYPE_DEFINITION = 13 56 IMAGE_SYM_CLASS_UNDEFINED_STATIC = 14 57 IMAGE_SYM_CLASS_ENUM_TAG = 15 58 IMAGE_SYM_CLASS_MEMBER_OF_ENUM = 16 59 IMAGE_SYM_CLASS_REGISTER_PARAM = 17 60 IMAGE_SYM_CLASS_BIT_FIELD = 18 61 IMAGE_SYM_CLASS_FAR_EXTERNAL = 68 /* Not in PECOFF v8 spec */ 62 IMAGE_SYM_CLASS_BLOCK = 100 63 IMAGE_SYM_CLASS_FUNCTION = 101 64 IMAGE_SYM_CLASS_END_OF_STRUCT = 102 65 IMAGE_SYM_CLASS_FILE = 103 66 IMAGE_SYM_CLASS_SECTION = 104 67 IMAGE_SYM_CLASS_WEAK_EXTERNAL = 105 68 IMAGE_SYM_CLASS_CLR_TOKEN = 107 69 IMAGE_REL_I386_ABSOLUTE = 0x0000 70 IMAGE_REL_I386_DIR16 = 0x0001 71 IMAGE_REL_I386_REL16 = 0x0002 72 IMAGE_REL_I386_DIR32 = 0x0006 73 IMAGE_REL_I386_DIR32NB = 0x0007 74 IMAGE_REL_I386_SEG12 = 0x0009 75 IMAGE_REL_I386_SECTION = 0x000A 76 IMAGE_REL_I386_SECREL = 0x000B 77 IMAGE_REL_I386_TOKEN = 0x000C 78 IMAGE_REL_I386_SECREL7 = 0x000D 79 IMAGE_REL_I386_REL32 = 0x0014 80 IMAGE_REL_AMD64_ABSOLUTE = 0x0000 81 IMAGE_REL_AMD64_ADDR64 = 0x0001 82 IMAGE_REL_AMD64_ADDR32 = 0x0002 83 IMAGE_REL_AMD64_ADDR32NB = 0x0003 84 IMAGE_REL_AMD64_REL32 = 0x0004 85 IMAGE_REL_AMD64_REL32_1 = 0x0005 86 IMAGE_REL_AMD64_REL32_2 = 0x0006 87 IMAGE_REL_AMD64_REL32_3 = 0x0007 88 IMAGE_REL_AMD64_REL32_4 = 0x0008 89 IMAGE_REL_AMD64_REL32_5 = 0x0009 90 IMAGE_REL_AMD64_SECTION = 0x000A 91 IMAGE_REL_AMD64_SECREL = 0x000B 92 IMAGE_REL_AMD64_SECREL7 = 0x000C 93 IMAGE_REL_AMD64_TOKEN = 0x000D 94 IMAGE_REL_AMD64_SREL32 = 0x000E 95 IMAGE_REL_AMD64_PAIR = 0x000F 96 IMAGE_REL_AMD64_SSPAN32 = 0x0010 97 ) 98 99 type PeSym struct { 100 name string 101 value uint32 102 sectnum uint16 103 type_ uint16 104 sclass uint8 105 aux uint8 106 sym *LSym 107 } 108 109 type PeSect struct { 110 name string 111 base []byte 112 size uint64 113 sym *LSym 114 sh IMAGE_SECTION_HEADER 115 } 116 117 type PeObj struct { 118 f *obj.Biobuf 119 name string 120 base uint32 121 sect []PeSect 122 nsect uint 123 pesym []PeSym 124 npesym uint 125 fh IMAGE_FILE_HEADER 126 snames []byte 127 } 128 129 func ldpe(f *obj.Biobuf, pkg string, length int64, pn string) { 130 if Debug['v'] != 0 { 131 fmt.Fprintf(&Bso, "%5.2f ldpe %s\n", obj.Cputime(), pn) 132 } 133 134 var sect *PeSect 135 Ctxt.Version++ 136 base := int32(obj.Boffset(f)) 137 138 peobj := new(PeObj) 139 peobj.f = f 140 peobj.base = uint32(base) 141 peobj.name = pn 142 143 // read header 144 var err error 145 var j int 146 var l uint32 147 var name string 148 var numaux int 149 var r []Reloc 150 var rp *Reloc 151 var rsect *PeSect 152 var s *LSym 153 var sym *PeSym 154 var symbuf [18]uint8 155 if err = binary.Read(f, binary.LittleEndian, &peobj.fh); err != nil { 156 goto bad 157 } 158 159 // load section list 160 peobj.sect = make([]PeSect, peobj.fh.NumberOfSections) 161 162 peobj.nsect = uint(peobj.fh.NumberOfSections) 163 for i := 0; i < int(peobj.fh.NumberOfSections); i++ { 164 if err = binary.Read(f, binary.LittleEndian, &peobj.sect[i].sh); err != nil { 165 goto bad 166 } 167 peobj.sect[i].size = uint64(peobj.sect[i].sh.SizeOfRawData) 168 peobj.sect[i].name = cstring(peobj.sect[i].sh.Name[:]) 169 } 170 171 // TODO return error if found .cormeta 172 173 // load string table 174 obj.Bseek(f, int64(base)+int64(peobj.fh.PointerToSymbolTable)+int64(len(symbuf))*int64(peobj.fh.NumberOfSymbols), 0) 175 176 if obj.Bread(f, symbuf[:4]) != 4 { 177 goto bad 178 } 179 l = Le32(symbuf[:]) 180 peobj.snames = make([]byte, l) 181 obj.Bseek(f, int64(base)+int64(peobj.fh.PointerToSymbolTable)+int64(len(symbuf))*int64(peobj.fh.NumberOfSymbols), 0) 182 if obj.Bread(f, peobj.snames) != len(peobj.snames) { 183 goto bad 184 } 185 186 // rewrite section names if they start with / 187 for i := 0; i < int(peobj.fh.NumberOfSections); i++ { 188 if peobj.sect[i].name == "" { 189 continue 190 } 191 if peobj.sect[i].name[0] != '/' { 192 continue 193 } 194 l = uint32(obj.Atoi(peobj.sect[i].name[1:])) 195 peobj.sect[i].name = cstring(peobj.snames[l:]) 196 } 197 198 // read symbols 199 peobj.pesym = make([]PeSym, peobj.fh.NumberOfSymbols) 200 201 peobj.npesym = uint(peobj.fh.NumberOfSymbols) 202 obj.Bseek(f, int64(base)+int64(peobj.fh.PointerToSymbolTable), 0) 203 for i := 0; uint32(i) < peobj.fh.NumberOfSymbols; i += numaux + 1 { 204 obj.Bseek(f, int64(base)+int64(peobj.fh.PointerToSymbolTable)+int64(len(symbuf))*int64(i), 0) 205 if obj.Bread(f, symbuf[:]) != len(symbuf) { 206 goto bad 207 } 208 209 if (symbuf[0] == 0) && (symbuf[1] == 0) && (symbuf[2] == 0) && (symbuf[3] == 0) { 210 l = Le32(symbuf[4:]) 211 peobj.pesym[i].name = cstring(peobj.snames[l:]) // sym name length <= 8 212 } else { 213 peobj.pesym[i].name = cstring(symbuf[:8]) 214 } 215 216 peobj.pesym[i].value = Le32(symbuf[8:]) 217 peobj.pesym[i].sectnum = Le16(symbuf[12:]) 218 peobj.pesym[i].sclass = symbuf[16] 219 peobj.pesym[i].aux = symbuf[17] 220 peobj.pesym[i].type_ = Le16(symbuf[14:]) 221 numaux = int(peobj.pesym[i].aux) 222 if numaux < 0 { 223 numaux = 0 224 } 225 } 226 227 // create symbols for mapped sections 228 for i := 0; uint(i) < peobj.nsect; i++ { 229 sect = &peobj.sect[i] 230 if sect.sh.Characteristics&IMAGE_SCN_MEM_DISCARDABLE != 0 { 231 continue 232 } 233 234 if sect.sh.Characteristics&(IMAGE_SCN_CNT_CODE|IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0 { 235 // This has been seen for .idata sections, which we 236 // want to ignore. See issues 5106 and 5273. 237 continue 238 } 239 240 if pemap(peobj, sect) < 0 { 241 goto bad 242 } 243 244 name = fmt.Sprintf("%s(%s)", pkg, sect.name) 245 s = Linklookup(Ctxt, name, Ctxt.Version) 246 247 switch sect.sh.Characteristics & (IMAGE_SCN_CNT_UNINITIALIZED_DATA | IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE | IMAGE_SCN_CNT_CODE | IMAGE_SCN_MEM_EXECUTE) { 248 case IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ: //.rdata 249 s.Type = obj.SRODATA 250 251 case IMAGE_SCN_CNT_UNINITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE: //.bss 252 s.Type = obj.SNOPTRBSS 253 254 case IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE: //.data 255 s.Type = obj.SNOPTRDATA 256 257 case IMAGE_SCN_CNT_CODE | IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_READ: //.text 258 s.Type = obj.STEXT 259 260 default: 261 err = fmt.Errorf("unexpected flags %#06x for PE section %s", sect.sh.Characteristics, sect.name) 262 goto bad 263 } 264 265 s.P = sect.base 266 s.P = s.P[:sect.size] 267 s.Size = int64(sect.size) 268 sect.sym = s 269 if sect.name == ".rsrc" { 270 setpersrc(sect.sym) 271 } 272 } 273 274 // load relocations 275 for i := 0; uint(i) < peobj.nsect; i++ { 276 rsect = &peobj.sect[i] 277 if rsect.sym == nil || rsect.sh.NumberOfRelocations == 0 { 278 continue 279 } 280 if rsect.sh.Characteristics&IMAGE_SCN_MEM_DISCARDABLE != 0 { 281 continue 282 } 283 if sect.sh.Characteristics&(IMAGE_SCN_CNT_CODE|IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_CNT_UNINITIALIZED_DATA) == 0 { 284 // This has been seen for .idata sections, which we 285 // want to ignore. See issues 5106 and 5273. 286 continue 287 } 288 289 r = make([]Reloc, rsect.sh.NumberOfRelocations) 290 obj.Bseek(f, int64(peobj.base)+int64(rsect.sh.PointerToRelocations), 0) 291 for j = 0; j < int(rsect.sh.NumberOfRelocations); j++ { 292 rp = &r[j] 293 if obj.Bread(f, symbuf[:10]) != 10 { 294 goto bad 295 } 296 rva := Le32(symbuf[0:]) 297 symindex := Le32(symbuf[4:]) 298 type_ := Le16(symbuf[8:]) 299 if err = readpesym(peobj, int(symindex), &sym); err != nil { 300 goto bad 301 } 302 if sym.sym == nil { 303 err = fmt.Errorf("reloc of invalid sym %s idx=%d type=%d", sym.name, symindex, sym.type_) 304 goto bad 305 } 306 307 rp.Sym = sym.sym 308 rp.Siz = 4 309 rp.Off = int32(rva) 310 switch type_ { 311 default: 312 Diag("%s: unknown relocation type %d;", pn, type_) 313 fallthrough 314 315 case IMAGE_REL_I386_REL32, IMAGE_REL_AMD64_REL32, 316 IMAGE_REL_AMD64_ADDR32, // R_X86_64_PC32 317 IMAGE_REL_AMD64_ADDR32NB: 318 rp.Type = obj.R_PCREL 319 320 rp.Add = int64(int32(Le32(rsect.base[rp.Off:]))) 321 322 case IMAGE_REL_I386_DIR32NB, IMAGE_REL_I386_DIR32: 323 rp.Type = obj.R_ADDR 324 325 // load addend from image 326 rp.Add = int64(int32(Le32(rsect.base[rp.Off:]))) 327 328 case IMAGE_REL_AMD64_ADDR64: // R_X86_64_64 329 rp.Siz = 8 330 331 rp.Type = obj.R_ADDR 332 333 // load addend from image 334 rp.Add = int64(Le64(rsect.base[rp.Off:])) 335 } 336 337 // ld -r could generate multiple section symbols for the 338 // same section but with different values, we have to take 339 // that into account 340 if issect(&peobj.pesym[symindex]) { 341 rp.Add += int64(peobj.pesym[symindex].value) 342 } 343 } 344 345 sort.Sort(rbyoff(r[:rsect.sh.NumberOfRelocations])) 346 347 s = rsect.sym 348 s.R = r 349 s.R = s.R[:rsect.sh.NumberOfRelocations] 350 } 351 352 // enter sub-symbols into symbol table. 353 for i := 0; uint(i) < peobj.npesym; i++ { 354 if peobj.pesym[i].name == "" { 355 continue 356 } 357 if issect(&peobj.pesym[i]) { 358 continue 359 } 360 if uint(peobj.pesym[i].sectnum) > peobj.nsect { 361 continue 362 } 363 if peobj.pesym[i].sectnum > 0 { 364 sect = &peobj.sect[peobj.pesym[i].sectnum-1] 365 if sect.sym == nil { 366 continue 367 } 368 } 369 370 if err = readpesym(peobj, i, &sym); err != nil { 371 goto bad 372 } 373 374 s = sym.sym 375 if sym.sectnum == 0 { // extern 376 if s.Type == obj.SDYNIMPORT { 377 s.Plt = -2 // flag for dynimport in PE object files. 378 } 379 if s.Type == obj.SXREF && sym.value > 0 { // global data 380 s.Type = obj.SNOPTRDATA 381 s.Size = int64(sym.value) 382 } 383 384 continue 385 } else if sym.sectnum > 0 && uint(sym.sectnum) <= peobj.nsect { 386 sect = &peobj.sect[sym.sectnum-1] 387 if sect.sym == nil { 388 Diag("%s: %s sym == 0!", pn, s.Name) 389 } 390 } else { 391 Diag("%s: %s sectnum < 0!", pn, s.Name) 392 } 393 394 if sect == nil { 395 return 396 } 397 398 if s.Outer != nil { 399 if s.Dupok != 0 { 400 continue 401 } 402 Exitf("%s: duplicate symbol reference: %s in both %s and %s", pn, s.Name, s.Outer.Name, sect.sym.Name) 403 } 404 405 s.Sub = sect.sym.Sub 406 sect.sym.Sub = s 407 s.Type = sect.sym.Type | obj.SSUB 408 s.Value = int64(sym.value) 409 s.Size = 4 410 s.Outer = sect.sym 411 if sect.sym.Type == obj.STEXT { 412 if s.External != 0 && s.Dupok == 0 { 413 Diag("%s: duplicate definition of %s", pn, s.Name) 414 } 415 s.External = 1 416 } 417 } 418 419 // Sort outer lists by address, adding to textp. 420 // This keeps textp in increasing address order. 421 for i := 0; uint(i) < peobj.nsect; i++ { 422 s = peobj.sect[i].sym 423 if s == nil { 424 continue 425 } 426 if s.Sub != nil { 427 s.Sub = listsort(s.Sub, valuecmp, listsubp) 428 } 429 if s.Type == obj.STEXT { 430 if s.Onlist != 0 { 431 log.Fatalf("symbol %s listed multiple times", s.Name) 432 } 433 s.Onlist = 1 434 if Ctxt.Etextp != nil { 435 Ctxt.Etextp.Next = s 436 } else { 437 Ctxt.Textp = s 438 } 439 Ctxt.Etextp = s 440 for s = s.Sub; s != nil; s = s.Sub { 441 if s.Onlist != 0 { 442 log.Fatalf("symbol %s listed multiple times", s.Name) 443 } 444 s.Onlist = 1 445 Ctxt.Etextp.Next = s 446 Ctxt.Etextp = s 447 } 448 } 449 } 450 451 return 452 453 bad: 454 Diag("%s: malformed pe file: %v", pn, err) 455 } 456 457 func pemap(peobj *PeObj, sect *PeSect) int { 458 if sect.base != nil { 459 return 0 460 } 461 462 sect.base = make([]byte, sect.sh.SizeOfRawData) 463 if sect.sh.PointerToRawData == 0 { // .bss doesn't have data in object file 464 return 0 465 } 466 if obj.Bseek(peobj.f, int64(peobj.base)+int64(sect.sh.PointerToRawData), 0) < 0 || obj.Bread(peobj.f, sect.base) != len(sect.base) { 467 return -1 468 } 469 470 return 0 471 } 472 473 func issect(s *PeSym) bool { 474 return s.sclass == IMAGE_SYM_CLASS_STATIC && s.type_ == 0 && s.name[0] == '.' 475 } 476 477 func readpesym(peobj *PeObj, i int, y **PeSym) (err error) { 478 if uint(i) >= peobj.npesym || i < 0 { 479 err = fmt.Errorf("invalid pe symbol index") 480 return err 481 } 482 483 sym := &peobj.pesym[i] 484 *y = sym 485 486 var name string 487 if issect(sym) { 488 name = peobj.sect[sym.sectnum-1].sym.Name 489 } else { 490 name = sym.name 491 if strings.HasPrefix(name, "__imp_") { 492 name = name[6:] // __imp_Name => Name 493 } 494 if Thearch.Thechar == '8' && name[0] == '_' { 495 name = name[1:] // _Name => Name 496 } 497 } 498 499 // remove last @XXX 500 if i := strings.LastIndex(name, "@"); i >= 0 { 501 name = name[:i] 502 } 503 504 var s *LSym 505 switch sym.type_ { 506 default: 507 err = fmt.Errorf("%s: invalid symbol type %d", sym.name, sym.type_) 508 return err 509 510 case IMAGE_SYM_DTYPE_FUNCTION, IMAGE_SYM_DTYPE_NULL: 511 switch sym.sclass { 512 case IMAGE_SYM_CLASS_EXTERNAL: //global 513 s = Linklookup(Ctxt, name, 0) 514 515 case IMAGE_SYM_CLASS_NULL, IMAGE_SYM_CLASS_STATIC, IMAGE_SYM_CLASS_LABEL: 516 s = Linklookup(Ctxt, name, Ctxt.Version) 517 s.Dupok = 1 518 519 default: 520 err = fmt.Errorf("%s: invalid symbol binding %d", sym.name, sym.sclass) 521 return err 522 } 523 } 524 525 if s != nil && s.Type == 0 && (sym.sclass != IMAGE_SYM_CLASS_STATIC || sym.value != 0) { 526 s.Type = obj.SXREF 527 } 528 if strings.HasPrefix(sym.name, "__imp_") { 529 s.Got = -2 // flag for __imp_ 530 } 531 sym.sym = s 532 533 return nil 534 } 535
