| 1 | // Copyright 2009 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 macho implements access to Mach-O object files. |
| 6 | package macho |
| 7 | |
| 8 | // High level access to low level data structures. |
| 9 | |
| 10 | import ( |
| 11 | "bytes" |
| 12 | "compress/zlib" |
| 13 | "debug/dwarf" |
| 14 | "encoding/binary" |
| 15 | "fmt" |
| 16 | "io" |
| 17 | "os" |
| 18 | "strings" |
| 19 | "unsafe" |
| 20 | ) |
| 21 | |
| 22 | // A File represents an open Mach-O file. |
| 23 | type File struct { |
| 24 | FileTOC |
| 25 | |
| 26 | Symtab *Symtab |
| 27 | Dysymtab *Dysymtab |
| 28 | |
| 29 | closer io.Closer |
| 30 | } |
| 31 | |
| 32 | type FileTOC struct { |
| 33 | FileHeader |
| 34 | ByteOrder binary.ByteOrder |
| 35 | Loads []Load |
| 36 | Sections []*Section |
| 37 | } |
| 38 | |
| 39 | func (t *FileTOC) AddLoad(l Load) { |
| 40 | t.Loads = append(t.Loads, l) |
| 41 | t.NCommands++ |
| 42 | t.SizeCommands += l.LoadSize(t) |
| 43 | } |
| 44 | |
| 45 | // AddSegment adds segment s to the file table of contents, |
| 46 | // and also zeroes out the segment information with the expectation |
| 47 | // that this will be added next. |
| 48 | func (t *FileTOC) AddSegment(s *Segment) { |
| 49 | t.AddLoad(s) |
| 50 | s.Nsect = 0 |
| 51 | s.Firstsect = 0 |
| 52 | } |
| 53 | |
| 54 | // Adds section to the most recently added Segment |
| 55 | func (t *FileTOC) AddSection(s *Section) { |
| 56 | g := t.Loads[len(t.Loads)-1].(*Segment) |
| 57 | if g.Nsect == 0 { |
| 58 | g.Firstsect = uint32(len(t.Sections)) |
| 59 | } |
| 60 | g.Nsect++ |
| 61 | t.Sections = append(t.Sections, s) |
| 62 | sectionsize := uint32(unsafe.Sizeof(Section32{})) |
| 63 | if g.Command() == LcSegment64 { |
| 64 | sectionsize = uint32(unsafe.Sizeof(Section64{})) |
| 65 | } |
| 66 | t.SizeCommands += sectionsize |
| 67 | g.Len += sectionsize |
| 68 | } |
| 69 | |
| 70 | // A Load represents any Mach-O load command. |
| 71 | type Load interface { |
| 72 | String() string |
| 73 | Command() LoadCmd |
| 74 | LoadSize(*FileTOC) uint32 // Need the TOC for alignment, sigh. |
| 75 | Put([]byte, binary.ByteOrder) int |
| 76 | |
| 77 | // command LC_DYLD_INFO_ONLY contains offsets into __LINKEDIT |
| 78 | // e.g., from "otool -l a.out" |
| 79 | // |
| 80 | // Load command 3 |
| 81 | // cmd LC_SEGMENT_64 |
| 82 | // cmdsize 72 |
| 83 | // segname __LINKEDIT |
| 84 | // vmaddr 0x0000000100002000 |
| 85 | // vmsize 0x0000000000001000 |
| 86 | // fileoff 8192 |
| 87 | // filesize 520 |
| 88 | // maxprot 0x00000007 |
| 89 | // initprot 0x00000001 |
| 90 | // nsects 0 |
| 91 | // flags 0x0 |
| 92 | // Load command 4 |
| 93 | // cmd LC_DYLD_INFO_ONLY |
| 94 | // cmdsize 48 |
| 95 | // rebase_off 8192 |
| 96 | // rebase_size 8 |
| 97 | // bind_off 8200 |
| 98 | // bind_size 24 |
| 99 | // weak_bind_off 0 |
| 100 | // weak_bind_size 0 |
| 101 | // lazy_bind_off 8224 |
| 102 | // lazy_bind_size 16 |
| 103 | // export_off 8240 |
| 104 | // export_size 48 |
| 105 | } |
| 106 | |
| 107 | // LoadBytes is the uninterpreted bytes of a Mach-O load command. |
| 108 | type LoadBytes []byte |
| 109 | |
| 110 | // A SegmentHeader is the header for a Mach-O 32-bit or 64-bit load segment command. |
| 111 | type SegmentHeader struct { |
| 112 | LoadCmd |
| 113 | Len uint32 |
| 114 | Name string // 16 characters or fewer |
| 115 | Addr uint64 // memory address |
| 116 | Memsz uint64 // memory size |
| 117 | Offset uint64 // file offset |
| 118 | Filesz uint64 // number of bytes starting at that file offset |
| 119 | Maxprot uint32 |
| 120 | Prot uint32 |
| 121 | Nsect uint32 |
| 122 | Flag SegFlags |
| 123 | Firstsect uint32 |
| 124 | } |
| 125 | |
| 126 | // A Segment represents a Mach-O 32-bit or 64-bit load segment command. |
| 127 | type Segment struct { |
| 128 | SegmentHeader |
| 129 | |
| 130 | // Embed ReaderAt for ReadAt method. |
| 131 | // Do not embed SectionReader directly |
| 132 | // to avoid having Read and Seek. |
| 133 | // If a client wants Read and Seek it must use |
| 134 | // Open() to avoid fighting over the seek offset |
| 135 | // with other clients. |
| 136 | io.ReaderAt |
| 137 | sr *io.SectionReader |
| 138 | } |
| 139 | |
| 140 | func (s *Segment) Put32(b []byte, o binary.ByteOrder) int { |
| 141 | o.PutUint32(b[0*4:], uint32(s.LoadCmd)) |
| 142 | o.PutUint32(b[1*4:], s.Len) |
| 143 | putAtMost16Bytes(b[2*4:], s.Name) |
| 144 | o.PutUint32(b[6*4:], uint32(s.Addr)) |
| 145 | o.PutUint32(b[7*4:], uint32(s.Memsz)) |
| 146 | o.PutUint32(b[8*4:], uint32(s.Offset)) |
| 147 | o.PutUint32(b[9*4:], uint32(s.Filesz)) |
| 148 | o.PutUint32(b[10*4:], s.Maxprot) |
| 149 | o.PutUint32(b[11*4:], s.Prot) |
| 150 | o.PutUint32(b[12*4:], s.Nsect) |
| 151 | o.PutUint32(b[13*4:], uint32(s.Flag)) |
| 152 | return 14 * 4 |
| 153 | } |
| 154 | |
| 155 | func (s *Segment) Put64(b []byte, o binary.ByteOrder) int { |
| 156 | o.PutUint32(b[0*4:], uint32(s.LoadCmd)) |
| 157 | o.PutUint32(b[1*4:], s.Len) |
| 158 | putAtMost16Bytes(b[2*4:], s.Name) |
| 159 | o.PutUint64(b[6*4+0*8:], s.Addr) |
| 160 | o.PutUint64(b[6*4+1*8:], s.Memsz) |
| 161 | o.PutUint64(b[6*4+2*8:], s.Offset) |
| 162 | o.PutUint64(b[6*4+3*8:], s.Filesz) |
| 163 | o.PutUint32(b[6*4+4*8:], s.Maxprot) |
| 164 | o.PutUint32(b[7*4+4*8:], s.Prot) |
| 165 | o.PutUint32(b[8*4+4*8:], s.Nsect) |
| 166 | o.PutUint32(b[9*4+4*8:], uint32(s.Flag)) |
| 167 | return 10*4 + 4*8 |
| 168 | } |
| 169 | |
| 170 | // LoadCmdBytes is a command-tagged sequence of bytes. |
| 171 | // This is used for Load Commands that are not (yet) |
| 172 | // interesting to us, and to common up this behavior for |
| 173 | // all those that are. |
| 174 | type LoadCmdBytes struct { |
| 175 | LoadCmd |
| 176 | LoadBytes |
| 177 | } |
| 178 | |
| 179 | type SectionHeader struct { |
| 180 | Name string |
| 181 | Seg string |
| 182 | Addr uint64 |
| 183 | Size uint64 |
| 184 | Offset uint32 |
| 185 | Align uint32 |
| 186 | Reloff uint32 |
| 187 | Nreloc uint32 |
| 188 | Flags SecFlags |
| 189 | Reserved1 uint32 |
| 190 | Reserved2 uint32 |
| 191 | Reserved3 uint32 // only present if original was 64-bit |
| 192 | } |
| 193 | |
| 194 | // A Reloc represents a Mach-O relocation. |
| 195 | type Reloc struct { |
| 196 | Addr uint32 |
| 197 | Value uint32 |
| 198 | // when Scattered == false && Extern == true, Value is the symbol number. |
| 199 | // when Scattered == false && Extern == false, Value is the section number. |
| 200 | // when Scattered == true, Value is the value that this reloc refers to. |
| 201 | Type uint8 |
| 202 | Len uint8 // 0=byte, 1=word, 2=long, 3=quad |
| 203 | Pcrel bool |
| 204 | Extern bool // valid if Scattered == false |
| 205 | Scattered bool |
| 206 | } |
| 207 | |
| 208 | type Section struct { |
| 209 | SectionHeader |
| 210 | Relocs []Reloc |
| 211 | |
| 212 | // Embed ReaderAt for ReadAt method. |
| 213 | // Do not embed SectionReader directly |
| 214 | // to avoid having Read and Seek. |
| 215 | // If a client wants Read and Seek it must use |
| 216 | // Open() to avoid fighting over the seek offset |
| 217 | // with other clients. |
| 218 | io.ReaderAt |
| 219 | sr *io.SectionReader |
| 220 | } |
| 221 | |
| 222 | func (s *Section) Put32(b []byte, o binary.ByteOrder) int { |
| 223 | putAtMost16Bytes(b[0:], s.Name) |
| 224 | putAtMost16Bytes(b[16:], s.Seg) |
| 225 | o.PutUint32(b[8*4:], uint32(s.Addr)) |
| 226 | o.PutUint32(b[9*4:], uint32(s.Size)) |
| 227 | o.PutUint32(b[10*4:], s.Offset) |
| 228 | o.PutUint32(b[11*4:], s.Align) |
| 229 | o.PutUint32(b[12*4:], s.Reloff) |
| 230 | o.PutUint32(b[13*4:], s.Nreloc) |
| 231 | o.PutUint32(b[14*4:], uint32(s.Flags)) |
| 232 | o.PutUint32(b[15*4:], s.Reserved1) |
| 233 | o.PutUint32(b[16*4:], s.Reserved2) |
| 234 | a := 17 * 4 |
| 235 | return a + s.PutRelocs(b[a:], o) |
| 236 | } |
| 237 | |
| 238 | func (s *Section) Put64(b []byte, o binary.ByteOrder) int { |
| 239 | putAtMost16Bytes(b[0:], s.Name) |
| 240 | putAtMost16Bytes(b[16:], s.Seg) |
| 241 | o.PutUint64(b[8*4+0*8:], s.Addr) |
| 242 | o.PutUint64(b[8*4+1*8:], s.Size) |
| 243 | o.PutUint32(b[8*4+2*8:], s.Offset) |
| 244 | o.PutUint32(b[9*4+2*8:], s.Align) |
| 245 | o.PutUint32(b[10*4+2*8:], s.Reloff) |
| 246 | o.PutUint32(b[11*4+2*8:], s.Nreloc) |
| 247 | o.PutUint32(b[12*4+2*8:], uint32(s.Flags)) |
| 248 | o.PutUint32(b[13*4+2*8:], s.Reserved1) |
| 249 | o.PutUint32(b[14*4+2*8:], s.Reserved2) |
| 250 | o.PutUint32(b[15*4+2*8:], s.Reserved3) |
| 251 | a := 16*4 + 2*8 |
| 252 | return a + s.PutRelocs(b[a:], o) |
| 253 | } |
| 254 | |
| 255 | func (s *Section) PutRelocs(b []byte, o binary.ByteOrder) int { |
| 256 | a := 0 |
| 257 | for _, r := range s.Relocs { |
| 258 | var ri relocInfo |
| 259 | typ := uint32(r.Type) & (1<<4 - 1) |
| 260 | len := uint32(r.Len) & (1<<2 - 1) |
| 261 | pcrel := uint32(0) |
| 262 | if r.Pcrel { |
| 263 | pcrel = 1 |
| 264 | } |
| 265 | ext := uint32(0) |
| 266 | if r.Extern { |
| 267 | ext = 1 |
| 268 | } |
| 269 | switch { |
| 270 | case r.Scattered: |
| 271 | ri.Addr = r.Addr&(1<<24-1) | typ<<24 | len<<28 | 1<<31 | pcrel<<30 |
| 272 | ri.Symnum = r.Value |
| 273 | case o == binary.LittleEndian: |
| 274 | ri.Addr = r.Addr |
| 275 | ri.Symnum = r.Value&(1<<24-1) | pcrel<<24 | len<<25 | ext<<27 | typ<<28 |
| 276 | case o == binary.BigEndian: |
| 277 | ri.Addr = r.Addr |
| 278 | ri.Symnum = r.Value<<8 | pcrel<<7 | len<<5 | ext<<4 | typ |
| 279 | } |
| 280 | o.PutUint32(b, ri.Addr) |
| 281 | o.PutUint32(b[4:], ri.Symnum) |
| 282 | a += 8 |
| 283 | b = b[8:] |
| 284 | } |
| 285 | return a |
| 286 | } |
| 287 | |
| 288 | func putAtMost16Bytes(b []byte, n string) { |
| 289 | for i := range n { // at most 16 bytes |
| 290 | if i == 16 { |
| 291 | break |
| 292 | } |
| 293 | b[i] = n[i] |
| 294 | } |
| 295 | } |
| 296 | |
| 297 | // A Symbol is a Mach-O 32-bit or 64-bit symbol table entry. |
| 298 | type Symbol struct { |
| 299 | Name string |
| 300 | Type uint8 |
| 301 | Sect uint8 |
| 302 | Desc uint16 |
| 303 | Value uint64 |
| 304 | } |
| 305 | |
| 306 | /* |
| 307 | * Mach-O reader |
| 308 | */ |
| 309 | |
| 310 | // FormatError is returned by some operations if the data does |
| 311 | // not have the correct format for an object file. |
| 312 | type FormatError struct { |
| 313 | off int64 |
| 314 | msg string |
| 315 | } |
| 316 | |
| 317 | func formatError(off int64, format string, data ...interface{}) *FormatError { |
| 318 | return &FormatError{off, fmt.Sprintf(format, data...)} |
| 319 | } |
| 320 | |
| 321 | func (e *FormatError) Error() string { |
| 322 | return e.msg + fmt.Sprintf(" in record at byte %#x", e.off) |
| 323 | } |
| 324 | |
| 325 | func (e *FormatError) String() string { |
| 326 | return e.Error() |
| 327 | } |
| 328 | |
| 329 | // DerivedCopy returns a modified copy of the TOC, with empty loads and sections, |
| 330 | // and with the specified header type and flags. |
| 331 | func (t *FileTOC) DerivedCopy(Type HdrType, Flags HdrFlags) *FileTOC { |
| 332 | h := t.FileHeader |
| 333 | h.NCommands, h.SizeCommands, h.Type, h.Flags = 0, 0, Type, Flags |
| 334 | |
| 335 | return &FileTOC{FileHeader: h, ByteOrder: t.ByteOrder} |
| 336 | } |
| 337 | |
| 338 | // TOCSize returns the size in bytes of the object file representation |
| 339 | // of the header and Load Commands (including Segments and Sections, but |
| 340 | // not their contents) at the beginning of a Mach-O file. This typically |
| 341 | // overlaps the text segment in the object file. |
| 342 | func (t *FileTOC) TOCSize() uint32 { |
| 343 | return t.HdrSize() + t.LoadSize() |
| 344 | } |
| 345 | |
| 346 | // LoadAlign returns the required alignment of Load commands in a binary. |
| 347 | // This is used to add padding for necessary alignment. |
| 348 | func (t *FileTOC) LoadAlign() uint64 { |
| 349 | if t.Magic == Magic64 { |
| 350 | return 8 |
| 351 | } |
| 352 | return 4 |
| 353 | } |
| 354 | |
| 355 | // SymbolSize returns the size in bytes of a Symbol (Nlist32 or Nlist64) |
| 356 | func (t *FileTOC) SymbolSize() uint32 { |
| 357 | if t.Magic == Magic64 { |
| 358 | return uint32(unsafe.Sizeof(Nlist64{})) |
| 359 | } |
| 360 | return uint32(unsafe.Sizeof(Nlist32{})) |
| 361 | } |
| 362 | |
| 363 | // HdrSize returns the size in bytes of the Macho header for a given |
| 364 | // magic number (where the magic number has been appropriately byte-swapped). |
| 365 | func (t *FileTOC) HdrSize() uint32 { |
| 366 | switch t.Magic { |
| 367 | case Magic32: |
| 368 | return fileHeaderSize32 |
| 369 | case Magic64: |
| 370 | return fileHeaderSize64 |
| 371 | case MagicFat: |
| 372 | panic("MagicFat not handled yet") |
| 373 | default: |
| 374 | panic(fmt.Sprintf("Unexpected magic number 0x%x, expected Mach-O object file", t.Magic)) |
| 375 | } |
| 376 | } |
| 377 | |
| 378 | // LoadSize returns the size of all the load commands in a file's table-of contents |
| 379 | // (but not their associated data, e.g., sections and symbol tables) |
| 380 | func (t *FileTOC) LoadSize() uint32 { |
| 381 | cmdsz := uint32(0) |
| 382 | for _, l := range t.Loads { |
| 383 | s := l.LoadSize(t) |
| 384 | cmdsz += s |
| 385 | } |
| 386 | return cmdsz |
| 387 | } |
| 388 | |
| 389 | // FileSize returns the size in bytes of the header, load commands, and the |
| 390 | // in-file contents of all the segments and sections included in those |
| 391 | // load commands, accounting for their offsets within the file. |
| 392 | func (t *FileTOC) FileSize() uint64 { |
| 393 | sz := uint64(t.LoadSize()) // ought to be contained in text segment, but just in case. |
| 394 | for _, l := range t.Loads { |
| 395 | if s, ok := l.(*Segment); ok { |
| 396 | if m := s.Offset + s.Filesz; m > sz { |
| 397 | sz = m |
| 398 | } |
| 399 | } |
| 400 | } |
| 401 | return sz |
| 402 | } |
| 403 | |
| 404 | // Put writes the header and all load commands to buffer, using |
| 405 | // the byte ordering specified in FileTOC t. For sections, this |
| 406 | // writes the headers that come in-line with the segment Load commands, |
| 407 | // but does not write the reference data for those sections. |
| 408 | func (t *FileTOC) Put(buffer []byte) int { |
| 409 | next := t.FileHeader.Put(buffer, t.ByteOrder) |
| 410 | for _, l := range t.Loads { |
| 411 | if s, ok := l.(*Segment); ok { |
| 412 | switch t.Magic { |
| 413 | case Magic64: |
| 414 | next += s.Put64(buffer[next:], t.ByteOrder) |
| 415 | for i := uint32(0); i < s.Nsect; i++ { |
| 416 | c := t.Sections[i+s.Firstsect] |
| 417 | next += c.Put64(buffer[next:], t.ByteOrder) |
| 418 | } |
| 419 | case Magic32: |
| 420 | next += s.Put32(buffer[next:], t.ByteOrder) |
| 421 | for i := uint32(0); i < s.Nsect; i++ { |
| 422 | c := t.Sections[i+s.Firstsect] |
| 423 | next += c.Put32(buffer[next:], t.ByteOrder) |
| 424 | } |
| 425 | default: |
| 426 | panic(fmt.Sprintf("Unexpected magic number 0x%x", t.Magic)) |
| 427 | } |
| 428 | |
| 429 | } else { |
| 430 | next += l.Put(buffer[next:], t.ByteOrder) |
| 431 | } |
| 432 | } |
| 433 | return next |
| 434 | } |
| 435 | |
| 436 | // UncompressedSize returns the size of the segment with its sections uncompressed, ignoring |
| 437 | // its offset within the file. The returned size is rounded up to the power of two in align. |
| 438 | func (s *Segment) UncompressedSize(t *FileTOC, align uint64) uint64 { |
| 439 | sz := uint64(0) |
| 440 | for j := uint32(0); j < s.Nsect; j++ { |
| 441 | c := t.Sections[j+s.Firstsect] |
| 442 | sz += c.UncompressedSize() |
| 443 | } |
| 444 | return (sz + align - 1) & uint64(-int64(align)) |
| 445 | } |
| 446 | |
| 447 | func (s *Section) UncompressedSize() uint64 { |
| 448 | if !strings.HasPrefix(s.Name, "__z") { |
| 449 | return s.Size |
| 450 | } |
| 451 | b := make([]byte, 12) |
| 452 | n, err := s.sr.ReadAt(b, 0) |
| 453 | if err != nil { |
| 454 | panic("Malformed object file") |
| 455 | } |
| 456 | if n != len(b) { |
| 457 | return s.Size |
| 458 | } |
| 459 | if string(b[:4]) == "ZLIB" { |
| 460 | return binary.BigEndian.Uint64(b[4:12]) |
| 461 | } |
| 462 | return s.Size |
| 463 | } |
| 464 | |
| 465 | func (s *Section) PutData(b []byte) { |
| 466 | bb := b[0:s.Size] |
| 467 | n, err := s.sr.ReadAt(bb, 0) |
| 468 | if err != nil || uint64(n) != s.Size { |
| 469 | panic("Malformed object file (ReadAt error)") |
| 470 | } |
| 471 | } |
| 472 | |
| 473 | func (s *Section) PutUncompressedData(b []byte) { |
| 474 | if strings.HasPrefix(s.Name, "__z") { |
| 475 | bb := make([]byte, 12) |
| 476 | n, err := s.sr.ReadAt(bb, 0) |
| 477 | if err != nil { |
| 478 | panic("Malformed object file") |
| 479 | } |
| 480 | if n == len(bb) && string(bb[:4]) == "ZLIB" { |
| 481 | size := binary.BigEndian.Uint64(bb[4:12]) |
| 482 | // Decompress starting at b[12:] |
| 483 | r, err := zlib.NewReader(io.NewSectionReader(s, 12, int64(size)-12)) |
| 484 | if err != nil { |
| 485 | panic("Malformed object file (zlib.NewReader error)") |
| 486 | } |
| 487 | n, err := io.ReadFull(r, b[0:size]) |
| 488 | if err != nil { |
| 489 | panic("Malformed object file (ReadFull error)") |
| 490 | } |
| 491 | if uint64(n) != size { |
| 492 | panic(fmt.Sprintf("PutUncompressedData, expected to read %d bytes, instead read %d", size, n)) |
| 493 | } |
| 494 | if err := r.Close(); err != nil { |
| 495 | panic("Malformed object file (Close error)") |
| 496 | } |
| 497 | return |
| 498 | } |
| 499 | } |
| 500 | // Not compressed |
| 501 | s.PutData(b) |
| 502 | } |
| 503 | |
| 504 | func (b LoadBytes) String() string { |
| 505 | s := "[" |
| 506 | for i, a := range b { |
| 507 | if i > 0 { |
| 508 | s += " " |
| 509 | if len(b) > 48 && i >= 16 { |
| 510 | s += fmt.Sprintf("... (%d bytes)", len(b)) |
| 511 | break |
| 512 | } |
| 513 | } |
| 514 | s += fmt.Sprintf("%x", a) |
| 515 | } |
| 516 | s += "]" |
| 517 | return s |
| 518 | } |
| 519 | |
| 520 | func (b LoadBytes) Raw() []byte { return b } |
| 521 | func (b LoadBytes) Copy() LoadBytes { return LoadBytes(append([]byte{}, b...)) } |
| 522 | func (b LoadBytes) LoadSize(t *FileTOC) uint32 { return uint32(len(b)) } |
| 523 | |
| 524 | func (lc LoadCmd) Put(b []byte, o binary.ByteOrder) int { |
| 525 | panic(fmt.Sprintf("Put not implemented for %s", lc.String())) |
| 526 | } |
| 527 | |
| 528 | func (s LoadCmdBytes) String() string { |
| 529 | return s.LoadCmd.String() + ": " + s.LoadBytes.String() |
| 530 | } |
| 531 | func (s LoadCmdBytes) Copy() LoadCmdBytes { |
| 532 | return LoadCmdBytes{LoadCmd: s.LoadCmd, LoadBytes: s.LoadBytes.Copy()} |
| 533 | } |
| 534 | |
| 535 | func (s *SegmentHeader) String() string { |
| 536 | return fmt.Sprintf( |
| 537 | "Seg %s, len=0x%x, addr=0x%x, memsz=0x%x, offset=0x%x, filesz=0x%x, maxprot=0x%x, prot=0x%x, nsect=%d, flag=0x%x, firstsect=%d", |
| 538 | s.Name, s.Len, s.Addr, s.Memsz, s.Offset, s.Filesz, s.Maxprot, s.Prot, s.Nsect, s.Flag, s.Firstsect) |
| 539 | } |
| 540 | |
| 541 | func (s *Segment) String() string { |
| 542 | return fmt.Sprintf( |
| 543 | "Seg %s, len=0x%x, addr=0x%x, memsz=0x%x, offset=0x%x, filesz=0x%x, maxprot=0x%x, prot=0x%x, nsect=%d, flag=0x%x, firstsect=%d", |
| 544 | s.Name, s.Len, s.Addr, s.Memsz, s.Offset, s.Filesz, s.Maxprot, s.Prot, s.Nsect, s.Flag, s.Firstsect) |
| 545 | } |
| 546 | |
| 547 | // Data reads and returns the contents of the segment. |
| 548 | func (s *Segment) Data() ([]byte, error) { |
| 549 | dat := make([]byte, s.sr.Size()) |
| 550 | n, err := s.sr.ReadAt(dat, 0) |
| 551 | if n == len(dat) { |
| 552 | err = nil |
| 553 | } |
| 554 | return dat[0:n], err |
| 555 | } |
| 556 | |
| 557 | func (s *Segment) Copy() *Segment { |
| 558 | r := &Segment{SegmentHeader: s.SegmentHeader} |
| 559 | return r |
| 560 | } |
| 561 | func (s *Segment) CopyZeroed() *Segment { |
| 562 | r := s.Copy() |
| 563 | r.Filesz = 0 |
| 564 | r.Offset = 0 |
| 565 | r.Nsect = 0 |
| 566 | r.Firstsect = 0 |
| 567 | if s.Command() == LcSegment64 { |
| 568 | r.Len = uint32(unsafe.Sizeof(Segment64{})) |
| 569 | } else { |
| 570 | r.Len = uint32(unsafe.Sizeof(Segment32{})) |
| 571 | } |
| 572 | return r |
| 573 | } |
| 574 | |
| 575 | func (s *Segment) LoadSize(t *FileTOC) uint32 { |
| 576 | if s.Command() == LcSegment64 { |
| 577 | return uint32(unsafe.Sizeof(Segment64{})) + uint32(s.Nsect)*uint32(unsafe.Sizeof(Section64{})) |
| 578 | } |
| 579 | return uint32(unsafe.Sizeof(Segment32{})) + uint32(s.Nsect)*uint32(unsafe.Sizeof(Section32{})) |
| 580 | } |
| 581 | |
| 582 | // Open returns a new ReadSeeker reading the segment. |
| 583 | func (s *Segment) Open() io.ReadSeeker { return io.NewSectionReader(s.sr, 0, 1<<63-1) } |
| 584 | |
| 585 | // Data reads and returns the contents of the Mach-O section. |
| 586 | func (s *Section) Data() ([]byte, error) { |
| 587 | dat := make([]byte, s.sr.Size()) |
| 588 | n, err := s.sr.ReadAt(dat, 0) |
| 589 | if n == len(dat) { |
| 590 | err = nil |
| 591 | } |
| 592 | return dat[0:n], err |
| 593 | } |
| 594 | |
| 595 | func (s *Section) Copy() *Section { |
| 596 | return &Section{SectionHeader: s.SectionHeader} |
| 597 | } |
| 598 | |
| 599 | // Open returns a new ReadSeeker reading the Mach-O section. |
| 600 | func (s *Section) Open() io.ReadSeeker { return io.NewSectionReader(s.sr, 0, 1<<63-1) } |
| 601 | |
| 602 | // A Dylib represents a Mach-O load dynamic library command. |
| 603 | type Dylib struct { |
| 604 | DylibCmd |
| 605 | Name string |
| 606 | Time uint32 |
| 607 | CurrentVersion uint32 |
| 608 | CompatVersion uint32 |
| 609 | } |
| 610 | |
| 611 | func (s *Dylib) String() string { return "Dylib " + s.Name } |
| 612 | func (s *Dylib) Copy() *Dylib { |
| 613 | r := *s |
| 614 | return &r |
| 615 | } |
| 616 | func (s *Dylib) LoadSize(t *FileTOC) uint32 { |
| 617 | return uint32(RoundUp(uint64(unsafe.Sizeof(DylibCmd{}))+uint64(len(s.Name)), t.LoadAlign())) |
| 618 | } |
| 619 | |
| 620 | type Dylinker struct { |
| 621 | DylinkerCmd // shared by 3 commands, need the LoadCmd |
| 622 | Name string |
| 623 | } |
| 624 | |
| 625 | func (s *Dylinker) String() string { return s.DylinkerCmd.LoadCmd.String() + " " + s.Name } |
| 626 | func (s *Dylinker) Copy() *Dylinker { |
| 627 | return &Dylinker{DylinkerCmd: s.DylinkerCmd, Name: s.Name} |
| 628 | } |
| 629 | func (s *Dylinker) LoadSize(t *FileTOC) uint32 { |
| 630 | return uint32(RoundUp(uint64(unsafe.Sizeof(DylinkerCmd{}))+uint64(len(s.Name)), t.LoadAlign())) |
| 631 | } |
| 632 | |
| 633 | // A Symtab represents a Mach-O symbol table command. |
| 634 | type Symtab struct { |
| 635 | SymtabCmd |
| 636 | Syms []Symbol |
| 637 | } |
| 638 | |
| 639 | func (s *Symtab) Put(b []byte, o binary.ByteOrder) int { |
| 640 | o.PutUint32(b[0*4:], uint32(s.LoadCmd)) |
| 641 | o.PutUint32(b[1*4:], s.Len) |
| 642 | o.PutUint32(b[2*4:], s.Symoff) |
| 643 | o.PutUint32(b[3*4:], s.Nsyms) |
| 644 | o.PutUint32(b[4*4:], s.Stroff) |
| 645 | o.PutUint32(b[5*4:], s.Strsize) |
| 646 | return 6 * 4 |
| 647 | } |
| 648 | |
| 649 | func (s *Symtab) String() string { return fmt.Sprintf("Symtab %#v", s.SymtabCmd) } |
| 650 | func (s *Symtab) Copy() *Symtab { |
| 651 | return &Symtab{SymtabCmd: s.SymtabCmd, Syms: append([]Symbol{}, s.Syms...)} |
| 652 | } |
| 653 | func (s *Symtab) LoadSize(t *FileTOC) uint32 { |
| 654 | return uint32(unsafe.Sizeof(SymtabCmd{})) |
| 655 | } |
| 656 | |
| 657 | type LinkEditData struct { |
| 658 | LinkEditDataCmd |
| 659 | } |
| 660 | |
| 661 | func (s *LinkEditData) String() string { return "LinkEditData " + s.LoadCmd.String() } |
| 662 | func (s *LinkEditData) Copy() *LinkEditData { |
| 663 | return &LinkEditData{LinkEditDataCmd: s.LinkEditDataCmd} |
| 664 | } |
| 665 | func (s *LinkEditData) LoadSize(t *FileTOC) uint32 { |
| 666 | return uint32(unsafe.Sizeof(LinkEditDataCmd{})) |
| 667 | } |
| 668 | |
| 669 | type Uuid struct { |
| 670 | UuidCmd |
| 671 | } |
| 672 | |
| 673 | func (s *Uuid) String() string { |
| 674 | return fmt.Sprintf("Uuid %X-%X-%X-%X-%X", |
| 675 | s.Id[0:4], s.Id[4:6], s.Id[6:8], s.Id[8:10], s.Id[10:16]) |
| 676 | } // 8-4-4-4-12 |
| 677 | func (s *Uuid) Copy() *Uuid { |
| 678 | return &Uuid{UuidCmd: s.UuidCmd} |
| 679 | } |
| 680 | func (s *Uuid) LoadSize(t *FileTOC) uint32 { |
| 681 | return uint32(unsafe.Sizeof(UuidCmd{})) |
| 682 | } |
| 683 | func (s *Uuid) Put(b []byte, o binary.ByteOrder) int { |
| 684 | o.PutUint32(b[0*4:], uint32(s.LoadCmd)) |
| 685 | o.PutUint32(b[1*4:], s.Len) |
| 686 | copy(b[2*4:], s.Id[0:]) |
| 687 | return int(s.Len) |
| 688 | } |
| 689 | |
| 690 | type DyldInfo struct { |
| 691 | DyldInfoCmd |
| 692 | } |
| 693 | |
| 694 | func (s *DyldInfo) String() string { return "DyldInfo " + s.LoadCmd.String() } |
| 695 | func (s *DyldInfo) Copy() *DyldInfo { |
| 696 | return &DyldInfo{DyldInfoCmd: s.DyldInfoCmd} |
| 697 | } |
| 698 | func (s *DyldInfo) LoadSize(t *FileTOC) uint32 { |
| 699 | return uint32(unsafe.Sizeof(DyldInfoCmd{})) |
| 700 | } |
| 701 | |
| 702 | type EncryptionInfo struct { |
| 703 | EncryptionInfoCmd |
| 704 | } |
| 705 | |
| 706 | func (s *EncryptionInfo) String() string { return "EncryptionInfo " + s.LoadCmd.String() } |
| 707 | func (s *EncryptionInfo) Copy() *EncryptionInfo { |
| 708 | return &EncryptionInfo{EncryptionInfoCmd: s.EncryptionInfoCmd} |
| 709 | } |
| 710 | func (s *EncryptionInfo) LoadSize(t *FileTOC) uint32 { |
| 711 | return uint32(unsafe.Sizeof(EncryptionInfoCmd{})) |
| 712 | } |
| 713 | |
| 714 | // A Dysymtab represents a Mach-O dynamic symbol table command. |
| 715 | type Dysymtab struct { |
| 716 | DysymtabCmd |
| 717 | IndirectSyms []uint32 // indices into Symtab.Syms |
| 718 | } |
| 719 | |
| 720 | func (s *Dysymtab) String() string { return fmt.Sprintf("Dysymtab %#v", s.DysymtabCmd) } |
| 721 | func (s *Dysymtab) Copy() *Dysymtab { |
| 722 | return &Dysymtab{DysymtabCmd: s.DysymtabCmd, IndirectSyms: append([]uint32{}, s.IndirectSyms...)} |
| 723 | } |
| 724 | func (s *Dysymtab) LoadSize(t *FileTOC) uint32 { |
| 725 | return uint32(unsafe.Sizeof(DysymtabCmd{})) |
| 726 | } |
| 727 | |
| 728 | // A Rpath represents a Mach-O rpath command. |
| 729 | type Rpath struct { |
| 730 | LoadCmd |
| 731 | Path string |
| 732 | } |
| 733 | |
| 734 | func (s *Rpath) String() string { return "Rpath " + s.Path } |
| 735 | func (s *Rpath) Command() LoadCmd { return LcRpath } |
| 736 | func (s *Rpath) Copy() *Rpath { |
| 737 | return &Rpath{Path: s.Path} |
| 738 | } |
| 739 | func (s *Rpath) LoadSize(t *FileTOC) uint32 { |
| 740 | return uint32(RoundUp(uint64(unsafe.Sizeof(RpathCmd{}))+uint64(len(s.Path)), t.LoadAlign())) |
| 741 | } |
| 742 | |
| 743 | // Open opens the named file using os.Open and prepares it for use as a Mach-O binary. |
| 744 | func Open(name string) (*File, error) { |
| 745 | f, err := os.Open(name) |
| 746 | if err != nil { |
| 747 | return nil, err |
| 748 | } |
| 749 | ff, err := NewFile(f) |
| 750 | if err != nil { |
| 751 | f.Close() |
| 752 | return nil, err |
| 753 | } |
| 754 | ff.closer = f |
| 755 | return ff, nil |
| 756 | } |
| 757 | |
| 758 | // Close closes the File. |
| 759 | // If the File was created using NewFile directly instead of Open, |
| 760 | // Close has no effect. |
| 761 | func (f *File) Close() error { |
| 762 | var err error |
| 763 | if f.closer != nil { |
| 764 | err = f.closer.Close() |
| 765 | f.closer = nil |
| 766 | } |
| 767 | return err |
| 768 | } |
| 769 | |
| 770 | // NewFile creates a new File for accessing a Mach-O binary in an underlying reader. |
| 771 | // The Mach-O binary is expected to start at position 0 in the ReaderAt. |
| 772 | func NewFile(r io.ReaderAt) (*File, error) { |
| 773 | f := new(File) |
| 774 | sr := io.NewSectionReader(r, 0, 1<<63-1) |
| 775 | |
| 776 | // Read and decode Mach magic to determine byte order, size. |
| 777 | // Magic32 and Magic64 differ only in the bottom bit. |
| 778 | var ident [4]byte |
| 779 | if _, err := r.ReadAt(ident[0:], 0); err != nil { |
| 780 | return nil, err |
| 781 | } |
| 782 | be := binary.BigEndian.Uint32(ident[0:]) |
| 783 | le := binary.LittleEndian.Uint32(ident[0:]) |
| 784 | switch Magic32 &^ 1 { |
| 785 | case be &^ 1: |
| 786 | f.ByteOrder = binary.BigEndian |
| 787 | f.Magic = be |
| 788 | case le &^ 1: |
| 789 | f.ByteOrder = binary.LittleEndian |
| 790 | f.Magic = le |
| 791 | default: |
| 792 | return nil, formatError(0, "invalid magic number be=0x%x, le=0x%x", be, le) |
| 793 | } |
| 794 | |
| 795 | // Read entire file header. |
| 796 | if err := binary.Read(sr, f.ByteOrder, &f.FileHeader); err != nil { |
| 797 | return nil, err |
| 798 | } |
| 799 | |
| 800 | // Then load commands. |
| 801 | offset := int64(fileHeaderSize32) |
| 802 | if f.Magic == Magic64 { |
| 803 | offset = fileHeaderSize64 |
| 804 | } |
| 805 | dat := make([]byte, f.SizeCommands) |
| 806 | if _, err := r.ReadAt(dat, offset); err != nil { |
| 807 | return nil, err |
| 808 | } |
| 809 | f.Loads = make([]Load, f.NCommands) |
| 810 | bo := f.ByteOrder |
| 811 | for i := range f.Loads { |
| 812 | // Each load command begins with uint32 command and length. |
| 813 | if len(dat) < 8 { |
| 814 | return nil, formatError(offset, "command block too small, len(dat) = %d", len(dat)) |
| 815 | } |
| 816 | cmd, siz := LoadCmd(bo.Uint32(dat[0:4])), bo.Uint32(dat[4:8]) |
| 817 | if siz < 8 || siz > uint32(len(dat)) { |
| 818 | return nil, formatError(offset, "invalid command block size, len(dat)=%d, size=%d", len(dat), siz) |
| 819 | } |
| 820 | var cmddat []byte |
| 821 | cmddat, dat = dat[0:siz], dat[siz:] |
| 822 | offset += int64(siz) |
| 823 | var s *Segment |
| 824 | switch cmd { |
| 825 | default: |
| 826 | f.Loads[i] = LoadCmdBytes{LoadCmd(cmd), LoadBytes(cmddat)} |
| 827 | |
| 828 | case LcUuid: |
| 829 | var hdr UuidCmd |
| 830 | b := bytes.NewReader(cmddat) |
| 831 | if err := binary.Read(b, bo, &hdr); err != nil { |
| 832 | return nil, err |
| 833 | } |
| 834 | l := &Uuid{UuidCmd: hdr} |
| 835 | |
| 836 | f.Loads[i] = l |
| 837 | |
| 838 | case LcRpath: |
| 839 | var hdr RpathCmd |
| 840 | b := bytes.NewReader(cmddat) |
| 841 | if err := binary.Read(b, bo, &hdr); err != nil { |
| 842 | return nil, err |
| 843 | } |
| 844 | l := &Rpath{LoadCmd: hdr.LoadCmd} |
| 845 | if hdr.Path >= uint32(len(cmddat)) { |
| 846 | return nil, formatError(offset, "invalid path in rpath command, len(cmddat)=%d, hdr.Path=%d", len(cmddat), hdr.Path) |
| 847 | } |
| 848 | l.Path = cstring(cmddat[hdr.Path:]) |
| 849 | f.Loads[i] = l |
| 850 | |
| 851 | case LcLoadDylinker, LcIdDylinker, LcDyldEnvironment: |
| 852 | var hdr DylinkerCmd |
| 853 | b := bytes.NewReader(cmddat) |
| 854 | if err := binary.Read(b, bo, &hdr); err != nil { |
| 855 | return nil, err |
| 856 | } |
| 857 | l := new(Dylinker) |
| 858 | if hdr.Name >= uint32(len(cmddat)) { |
| 859 | return nil, formatError(offset, "invalid name in dynamic linker command, hdr.Name=%d, len(cmddat)=%d", hdr.Name, len(cmddat)) |
| 860 | } |
| 861 | l.Name = cstring(cmddat[hdr.Name:]) |
| 862 | l.DylinkerCmd = hdr |
| 863 | f.Loads[i] = l |
| 864 | |
| 865 | case LcDylib: |
| 866 | var hdr DylibCmd |
| 867 | b := bytes.NewReader(cmddat) |
| 868 | if err := binary.Read(b, bo, &hdr); err != nil { |
| 869 | return nil, err |
| 870 | } |
| 871 | l := new(Dylib) |
| 872 | if hdr.Name >= uint32(len(cmddat)) { |
| 873 | return nil, formatError(offset, "invalid name in dynamic library command, hdr.Name=%d, len(cmddat)=%d", hdr.Name, len(cmddat)) |
| 874 | } |
| 875 | l.Name = cstring(cmddat[hdr.Name:]) |
| 876 | l.Time = hdr.Time |
| 877 | l.CurrentVersion = hdr.CurrentVersion |
| 878 | l.CompatVersion = hdr.CompatVersion |
| 879 | f.Loads[i] = l |
| 880 | |
| 881 | case LcSymtab: |
| 882 | var hdr SymtabCmd |
| 883 | b := bytes.NewReader(cmddat) |
| 884 | if err := binary.Read(b, bo, &hdr); err != nil { |
| 885 | return nil, err |
| 886 | } |
| 887 | strtab := make([]byte, hdr.Strsize) |
| 888 | if _, err := r.ReadAt(strtab, int64(hdr.Stroff)); err != nil { |
| 889 | return nil, err |
| 890 | } |
| 891 | var symsz int |
| 892 | if f.Magic == Magic64 { |
| 893 | symsz = 16 |
| 894 | } else { |
| 895 | symsz = 12 |
| 896 | } |
| 897 | symdat := make([]byte, int(hdr.Nsyms)*symsz) |
| 898 | if _, err := r.ReadAt(symdat, int64(hdr.Symoff)); err != nil { |
| 899 | return nil, err |
| 900 | } |
| 901 | st, err := f.parseSymtab(symdat, strtab, cmddat, &hdr, offset) |
| 902 | st.SymtabCmd = hdr |
| 903 | if err != nil { |
| 904 | return nil, err |
| 905 | } |
| 906 | f.Loads[i] = st |
| 907 | f.Symtab = st |
| 908 | |
| 909 | case LcDysymtab: |
| 910 | var hdr DysymtabCmd |
| 911 | b := bytes.NewReader(cmddat) |
| 912 | if err := binary.Read(b, bo, &hdr); err != nil { |
| 913 | return nil, err |
| 914 | } |
| 915 | dat := make([]byte, hdr.Nindirectsyms*4) |
| 916 | if _, err := r.ReadAt(dat, int64(hdr.Indirectsymoff)); err != nil { |
| 917 | return nil, err |
| 918 | } |
| 919 | x := make([]uint32, hdr.Nindirectsyms) |
| 920 | if err := binary.Read(bytes.NewReader(dat), bo, x); err != nil { |
| 921 | return nil, err |
| 922 | } |
| 923 | st := new(Dysymtab) |
| 924 | st.DysymtabCmd = hdr |
| 925 | st.IndirectSyms = x |
| 926 | f.Loads[i] = st |
| 927 | f.Dysymtab = st |
| 928 | |
| 929 | case LcSegment: |
| 930 | var seg32 Segment32 |
| 931 | b := bytes.NewReader(cmddat) |
| 932 | if err := binary.Read(b, bo, &seg32); err != nil { |
| 933 | return nil, err |
| 934 | } |
| 935 | s = new(Segment) |
| 936 | s.LoadCmd = cmd |
| 937 | s.Len = siz |
| 938 | s.Name = cstring(seg32.Name[0:]) |
| 939 | s.Addr = uint64(seg32.Addr) |
| 940 | s.Memsz = uint64(seg32.Memsz) |
| 941 | s.Offset = uint64(seg32.Offset) |
| 942 | s.Filesz = uint64(seg32.Filesz) |
| 943 | s.Maxprot = seg32.Maxprot |
| 944 | s.Prot = seg32.Prot |
| 945 | s.Nsect = seg32.Nsect |
| 946 | s.Flag = seg32.Flag |
| 947 | s.Firstsect = uint32(len(f.Sections)) |
| 948 | f.Loads[i] = s |
| 949 | for i := 0; i < int(s.Nsect); i++ { |
| 950 | var sh32 Section32 |
| 951 | if err := binary.Read(b, bo, &sh32); err != nil { |
| 952 | return nil, err |
| 953 | } |
| 954 | sh := new(Section) |
| 955 | sh.Name = cstring(sh32.Name[0:]) |
| 956 | sh.Seg = cstring(sh32.Seg[0:]) |
| 957 | sh.Addr = uint64(sh32.Addr) |
| 958 | sh.Size = uint64(sh32.Size) |
| 959 | sh.Offset = sh32.Offset |
| 960 | sh.Align = sh32.Align |
| 961 | sh.Reloff = sh32.Reloff |
| 962 | sh.Nreloc = sh32.Nreloc |
| 963 | sh.Flags = sh32.Flags |
| 964 | sh.Reserved1 = sh32.Reserve1 |
| 965 | sh.Reserved2 = sh32.Reserve2 |
| 966 | if err := f.pushSection(sh, r); err != nil { |
| 967 | return nil, err |
| 968 | } |
| 969 | } |
| 970 | |
| 971 | case LcSegment64: |
| 972 | var seg64 Segment64 |
| 973 | b := bytes.NewReader(cmddat) |
| 974 | if err := binary.Read(b, bo, &seg64); err != nil { |
| 975 | return nil, err |
| 976 | } |
| 977 | s = new(Segment) |
| 978 | s.LoadCmd = cmd |
| 979 | s.Len = siz |
| 980 | s.Name = cstring(seg64.Name[0:]) |
| 981 | s.Addr = seg64.Addr |
| 982 | s.Memsz = seg64.Memsz |
| 983 | s.Offset = seg64.Offset |
| 984 | s.Filesz = seg64.Filesz |
| 985 | s.Maxprot = seg64.Maxprot |
| 986 | s.Prot = seg64.Prot |
| 987 | s.Nsect = seg64.Nsect |
| 988 | s.Flag = seg64.Flag |
| 989 | s.Firstsect = uint32(len(f.Sections)) |
| 990 | f.Loads[i] = s |
| 991 | for i := 0; i < int(s.Nsect); i++ { |
| 992 | var sh64 Section64 |
| 993 | if err := binary.Read(b, bo, &sh64); err != nil { |
| 994 | return nil, err |
| 995 | } |
| 996 | sh := new(Section) |
| 997 | sh.Name = cstring(sh64.Name[0:]) |
| 998 | sh.Seg = cstring(sh64.Seg[0:]) |
| 999 | sh.Addr = sh64.Addr |
| 1000 | sh.Size = sh64.Size |
| 1001 | sh.Offset = sh64.Offset |
| 1002 | sh.Align = sh64.Align |
| 1003 | sh.Reloff = sh64.Reloff |
| 1004 | sh.Nreloc = sh64.Nreloc |
| 1005 | sh.Flags = sh64.Flags |
| 1006 | sh.Reserved1 = sh64.Reserve1 |
| 1007 | sh.Reserved2 = sh64.Reserve2 |
| 1008 | sh.Reserved3 = sh64.Reserve3 |
| 1009 | if err := f.pushSection(sh, r); err != nil { |
| 1010 | return nil, err |
| 1011 | } |
| 1012 | } |
| 1013 | |
| 1014 | case LcCodeSignature, LcSegmentSplitInfo, LcFunctionStarts, |
| 1015 | LcDataInCode, LcDylibCodeSignDrs: |
| 1016 | var hdr LinkEditDataCmd |
| 1017 | b := bytes.NewReader(cmddat) |
| 1018 | |
| 1019 | if err := binary.Read(b, bo, &hdr); err != nil { |
| 1020 | return nil, err |
| 1021 | } |
| 1022 | l := new(LinkEditData) |
| 1023 | |
| 1024 | l.LinkEditDataCmd = hdr |
| 1025 | f.Loads[i] = l |
| 1026 | |
| 1027 | case LcEncryptionInfo, LcEncryptionInfo64: |
| 1028 | var hdr EncryptionInfoCmd |
| 1029 | b := bytes.NewReader(cmddat) |
| 1030 | |
| 1031 | if err := binary.Read(b, bo, &hdr); err != nil { |
| 1032 | return nil, err |
| 1033 | } |
| 1034 | l := new(EncryptionInfo) |
| 1035 | |
| 1036 | l.EncryptionInfoCmd = hdr |
| 1037 | f.Loads[i] = l |
| 1038 | |
| 1039 | case LcDyldInfo, LcDyldInfoOnly: |
| 1040 | var hdr DyldInfoCmd |
| 1041 | b := bytes.NewReader(cmddat) |
| 1042 | |
| 1043 | if err := binary.Read(b, bo, &hdr); err != nil { |
| 1044 | return nil, err |
| 1045 | } |
| 1046 | l := new(DyldInfo) |
| 1047 | |
| 1048 | l.DyldInfoCmd = hdr |
| 1049 | f.Loads[i] = l |
| 1050 | } |
| 1051 | if s != nil { |
| 1052 | s.sr = io.NewSectionReader(r, int64(s.Offset), int64(s.Filesz)) |
| 1053 | s.ReaderAt = s.sr |
| 1054 | } |
| 1055 | if f.Loads[i].LoadSize(&f.FileTOC) != siz { |
| 1056 | fmt.Printf("Oops, actual size was %d, calculated was %d, load was %s\n", siz, f.Loads[i].LoadSize(&f.FileTOC), f.Loads[i].String()) |
| 1057 | panic("oops") |
| 1058 | } |
| 1059 | } |
| 1060 | return f, nil |
| 1061 | } |
| 1062 | |
| 1063 | func (f *File) parseSymtab(symdat, strtab, cmddat []byte, hdr *SymtabCmd, offset int64) (*Symtab, error) { |
| 1064 | bo := f.ByteOrder |
| 1065 | symtab := make([]Symbol, hdr.Nsyms) |
| 1066 | b := bytes.NewReader(symdat) |
| 1067 | for i := range symtab { |
| 1068 | var n Nlist64 |
| 1069 | if f.Magic == Magic64 { |
| 1070 | if err := binary.Read(b, bo, &n); err != nil { |
| 1071 | return nil, err |
| 1072 | } |
| 1073 | } else { |
| 1074 | var n32 Nlist32 |
| 1075 | if err := binary.Read(b, bo, &n32); err != nil { |
| 1076 | return nil, err |
| 1077 | } |
| 1078 | n.Name = n32.Name |
| 1079 | n.Type = n32.Type |
| 1080 | n.Sect = n32.Sect |
| 1081 | n.Desc = n32.Desc |
| 1082 | n.Value = uint64(n32.Value) |
| 1083 | } |
| 1084 | sym := &symtab[i] |
| 1085 | if n.Name >= uint32(len(strtab)) { |
| 1086 | return nil, formatError(offset, "invalid name in symbol table, n.Name=%d, len(strtab)=%d", n.Name, len(strtab)) |
| 1087 | } |
| 1088 | sym.Name = cstring(strtab[n.Name:]) |
| 1089 | sym.Type = n.Type |
| 1090 | sym.Sect = n.Sect |
| 1091 | sym.Desc = n.Desc |
| 1092 | sym.Value = n.Value |
| 1093 | } |
| 1094 | st := new(Symtab) |
| 1095 | st.Syms = symtab |
| 1096 | return st, nil |
| 1097 | } |
| 1098 | |
| 1099 | type relocInfo struct { |
| 1100 | Addr uint32 |
| 1101 | Symnum uint32 |
| 1102 | } |
| 1103 | |
| 1104 | func (f *File) pushSection(sh *Section, r io.ReaderAt) error { |
| 1105 | f.Sections = append(f.Sections, sh) |
| 1106 | sh.sr = io.NewSectionReader(r, int64(sh.Offset), int64(sh.Size)) |
| 1107 | sh.ReaderAt = sh.sr |
| 1108 | |
| 1109 | if sh.Nreloc > 0 { |
| 1110 | reldat := make([]byte, int(sh.Nreloc)*8) |
| 1111 | if _, err := r.ReadAt(reldat, int64(sh.Reloff)); err != nil { |
| 1112 | return err |
| 1113 | } |
| 1114 | b := bytes.NewReader(reldat) |
| 1115 | |
| 1116 | bo := f.ByteOrder |
| 1117 | |
| 1118 | sh.Relocs = make([]Reloc, sh.Nreloc) |
| 1119 | for i := range sh.Relocs { |
| 1120 | rel := &sh.Relocs[i] |
| 1121 | |
| 1122 | var ri relocInfo |
| 1123 | if err := binary.Read(b, bo, &ri); err != nil { |
| 1124 | return err |
| 1125 | } |
| 1126 | |
| 1127 | if ri.Addr&(1<<31) != 0 { // scattered |
| 1128 | rel.Addr = ri.Addr & (1<<24 - 1) |
| 1129 | rel.Type = uint8((ri.Addr >> 24) & (1<<4 - 1)) |
| 1130 | rel.Len = uint8((ri.Addr >> 28) & (1<<2 - 1)) |
| 1131 | rel.Pcrel = ri.Addr&(1<<30) != 0 |
| 1132 | rel.Value = ri.Symnum |
| 1133 | rel.Scattered = true |
| 1134 | } else { |
| 1135 | switch bo { |
| 1136 | case binary.LittleEndian: |
| 1137 | rel.Addr = ri.Addr |
| 1138 | rel.Value = ri.Symnum & (1<<24 - 1) |
| 1139 | rel.Pcrel = ri.Symnum&(1<<24) != 0 |
| 1140 | rel.Len = uint8((ri.Symnum >> 25) & (1<<2 - 1)) |
| 1141 | rel.Extern = ri.Symnum&(1<<27) != 0 |
| 1142 | rel.Type = uint8((ri.Symnum >> 28) & (1<<4 - 1)) |
| 1143 | case binary.BigEndian: |
| 1144 | rel.Addr = ri.Addr |
| 1145 | rel.Value = ri.Symnum >> 8 |
| 1146 | rel.Pcrel = ri.Symnum&(1<<7) != 0 |
| 1147 | rel.Len = uint8((ri.Symnum >> 5) & (1<<2 - 1)) |
| 1148 | rel.Extern = ri.Symnum&(1<<4) != 0 |
| 1149 | rel.Type = uint8(ri.Symnum & (1<<4 - 1)) |
| 1150 | default: |
| 1151 | panic("unreachable") |
| 1152 | } |
| 1153 | } |
| 1154 | } |
| 1155 | } |
| 1156 | |
| 1157 | return nil |
| 1158 | } |
| 1159 | |
| 1160 | func cstring(b []byte) string { |
| 1161 | i := bytes.IndexByte(b, 0) |
| 1162 | if i == -1 { |
| 1163 | i = len(b) |
| 1164 | } |
| 1165 | return string(b[0:i]) |
| 1166 | } |
| 1167 | |
| 1168 | // Segment returns the first Segment with the given name, or nil if no such segment exists. |
| 1169 | func (f *File) Segment(name string) *Segment { |
| 1170 | for _, l := range f.Loads { |
| 1171 | if s, ok := l.(*Segment); ok && s.Name == name { |
| 1172 | return s |
| 1173 | } |
| 1174 | } |
| 1175 | return nil |
| 1176 | } |
| 1177 | |
| 1178 | // Section returns the first section with the given name, or nil if no such |
| 1179 | // section exists. |
| 1180 | func (f *File) Section(name string) *Section { |
| 1181 | for _, s := range f.Sections { |
| 1182 | if s.Name == name { |
| 1183 | return s |
| 1184 | } |
| 1185 | } |
| 1186 | return nil |
| 1187 | } |
| 1188 | |
| 1189 | // DWARF returns the DWARF debug information for the Mach-O file. |
| 1190 | func (f *File) DWARF() (*dwarf.Data, error) { |
| 1191 | dwarfSuffix := func(s *Section) string { |
| 1192 | switch { |
| 1193 | case strings.HasPrefix(s.Name, "__debug_"): |
| 1194 | return s.Name[8:] |
| 1195 | case strings.HasPrefix(s.Name, "__zdebug_"): |
| 1196 | return s.Name[9:] |
| 1197 | default: |
| 1198 | return "" |
| 1199 | } |
| 1200 | |
| 1201 | } |
| 1202 | sectionData := func(s *Section) ([]byte, error) { |
| 1203 | b, err := s.Data() |
| 1204 | if err != nil && uint64(len(b)) < s.Size { |
| 1205 | return nil, err |
| 1206 | } |
| 1207 | |
| 1208 | if len(b) >= 12 && string(b[:4]) == "ZLIB" { |
| 1209 | dlen := binary.BigEndian.Uint64(b[4:12]) |
| 1210 | dbuf := make([]byte, dlen) |
| 1211 | r, err := zlib.NewReader(bytes.NewBuffer(b[12:])) |
| 1212 | if err != nil { |
| 1213 | return nil, err |
| 1214 | } |
| 1215 | if _, err := io.ReadFull(r, dbuf); err != nil { |
| 1216 | return nil, err |
| 1217 | } |
| 1218 | if err := r.Close(); err != nil { |
| 1219 | return nil, err |
| 1220 | } |
| 1221 | b = dbuf |
| 1222 | } |
| 1223 | return b, nil |
| 1224 | } |
| 1225 | |
| 1226 | // There are many other DWARF sections, but these |
| 1227 | // are the ones the debug/dwarf package uses. |
| 1228 | // Don't bother loading others. |
| 1229 | var dat = map[string][]byte{"abbrev": nil, "info": nil, "str": nil, "line": nil, "ranges": nil} |
| 1230 | for _, s := range f.Sections { |
| 1231 | suffix := dwarfSuffix(s) |
| 1232 | if suffix == "" { |
| 1233 | continue |
| 1234 | } |
| 1235 | if _, ok := dat[suffix]; !ok { |
| 1236 | continue |
| 1237 | } |
| 1238 | b, err := sectionData(s) |
| 1239 | if err != nil { |
| 1240 | return nil, err |
| 1241 | } |
| 1242 | dat[suffix] = b |
| 1243 | } |
| 1244 | |
| 1245 | d, err := dwarf.New(dat["abbrev"], nil, nil, dat["info"], dat["line"], nil, dat["ranges"], dat["str"]) |
| 1246 | if err != nil { |
| 1247 | return nil, err |
| 1248 | } |
| 1249 | |
| 1250 | // Look for DWARF4 .debug_types sections. |
| 1251 | for i, s := range f.Sections { |
| 1252 | suffix := dwarfSuffix(s) |
| 1253 | if suffix != "types" { |
| 1254 | continue |
| 1255 | } |
| 1256 | |
| 1257 | b, err := sectionData(s) |
| 1258 | if err != nil { |
| 1259 | return nil, err |
| 1260 | } |
| 1261 | |
| 1262 | err = d.AddTypes(fmt.Sprintf("types-%d", i), b) |
| 1263 | if err != nil { |
| 1264 | return nil, err |
| 1265 | } |
| 1266 | } |
| 1267 | |
| 1268 | return d, nil |
| 1269 | } |
| 1270 | |
| 1271 | // ImportedSymbols returns the names of all symbols |
| 1272 | // referred to by the binary f that are expected to be |
| 1273 | // satisfied by other libraries at dynamic load time. |
| 1274 | func (f *File) ImportedSymbols() ([]string, error) { |
| 1275 | if f.Dysymtab == nil || f.Symtab == nil { |
| 1276 | return nil, formatError(0, "missing symbol table, f.Dsymtab=%v, f.Symtab=%v", f.Dysymtab, f.Symtab) |
| 1277 | } |
| 1278 | |
| 1279 | st := f.Symtab |
| 1280 | dt := f.Dysymtab |
| 1281 | var all []string |
| 1282 | for _, s := range st.Syms[dt.Iundefsym : dt.Iundefsym+dt.Nundefsym] { |
| 1283 | all = append(all, s.Name) |
| 1284 | } |
| 1285 | return all, nil |
| 1286 | } |
| 1287 | |
| 1288 | // ImportedLibraries returns the paths of all libraries |
| 1289 | // referred to by the binary f that are expected to be |
| 1290 | // linked with the binary at dynamic link time. |
| 1291 | func (f *File) ImportedLibraries() ([]string, error) { |
| 1292 | var all []string |
| 1293 | for _, l := range f.Loads { |
| 1294 | if lib, ok := l.(*Dylib); ok { |
| 1295 | all = append(all, lib.Name) |
| 1296 | } |
| 1297 | } |
| 1298 | return all, nil |
| 1299 | } |
| 1300 | |
| 1301 | func RoundUp(x, align uint64) uint64 { |
| 1302 | return uint64((x + align - 1) & -align) |
| 1303 | } |
| 1304 |
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