--- /dev/null
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package macho implements access to Mach-O object files.
+package macho
+
+// High level access to low level data structures.
+
+import (
+ "bytes"
+ "compress/zlib"
+ "debug/dwarf"
+ "encoding/binary"
+ "fmt"
+ "io"
+ "os"
+ "strings"
+ "unsafe"
+)
+
+// A File represents an open Mach-O file.
+type File struct {
+ FileTOC
+
+ Symtab *Symtab
+ Dysymtab *Dysymtab
+
+ closer io.Closer
+}
+
+type FileTOC struct {
+ FileHeader
+ ByteOrder binary.ByteOrder
+ Loads []Load
+ Sections []*Section
+}
+
+func (t *FileTOC) AddLoad(l Load) {
+ t.Loads = append(t.Loads, l)
+ t.NCommands++
+ t.SizeCommands += l.LoadSize(t)
+}
+
+// AddSegment adds segment s to the file table of contents,
+// and also zeroes out the segment information with the expectation
+// that this will be added next.
+func (t *FileTOC) AddSegment(s *Segment) {
+ t.AddLoad(s)
+ s.Nsect = 0
+ s.Firstsect = 0
+}
+
+// Adds section to the most recently added Segment
+func (t *FileTOC) AddSection(s *Section) {
+ g := t.Loads[len(t.Loads)-1].(*Segment)
+ if g.Nsect == 0 {
+ g.Firstsect = uint32(len(t.Sections))
+ }
+ g.Nsect++
+ t.Sections = append(t.Sections, s)
+ sectionsize := uint32(unsafe.Sizeof(Section32{}))
+ if g.Command() == LcSegment64 {
+ sectionsize = uint32(unsafe.Sizeof(Section64{}))
+ }
+ t.SizeCommands += sectionsize
+ g.Len += sectionsize
+}
+
+// A Load represents any Mach-O load command.
+type Load interface {
+ String() string
+ Command() LoadCmd
+ LoadSize(*FileTOC) uint32 // Need the TOC for alignment, sigh.
+ Put([]byte, binary.ByteOrder) int
+
+ // command LC_DYLD_INFO_ONLY contains offsets into __LINKEDIT
+ // e.g., from "otool -l a.out"
+ //
+ // Load command 3
+ // cmd LC_SEGMENT_64
+ // cmdsize 72
+ // segname __LINKEDIT
+ // vmaddr 0x0000000100002000
+ // vmsize 0x0000000000001000
+ // fileoff 8192
+ // filesize 520
+ // maxprot 0x00000007
+ // initprot 0x00000001
+ // nsects 0
+ // flags 0x0
+ // Load command 4
+ // cmd LC_DYLD_INFO_ONLY
+ // cmdsize 48
+ // rebase_off 8192
+ // rebase_size 8
+ // bind_off 8200
+ // bind_size 24
+ // weak_bind_off 0
+ // weak_bind_size 0
+ // lazy_bind_off 8224
+ // lazy_bind_size 16
+ // export_off 8240
+ // export_size 48
+}
+
+// LoadBytes is the uninterpreted bytes of a Mach-O load command.
+type LoadBytes []byte
+
+// A SegmentHeader is the header for a Mach-O 32-bit or 64-bit load segment command.
+type SegmentHeader struct {
+ LoadCmd
+ Len uint32
+ Name string // 16 characters or fewer
+ Addr uint64 // memory address
+ Memsz uint64 // memory size
+ Offset uint64 // file offset
+ Filesz uint64 // number of bytes starting at that file offset
+ Maxprot uint32
+ Prot uint32
+ Nsect uint32
+ Flag SegFlags
+ Firstsect uint32
+}
+
+// A Segment represents a Mach-O 32-bit or 64-bit load segment command.
+type Segment struct {
+ SegmentHeader
+
+ // Embed ReaderAt for ReadAt method.
+ // Do not embed SectionReader directly
+ // to avoid having Read and Seek.
+ // If a client wants Read and Seek it must use
+ // Open() to avoid fighting over the seek offset
+ // with other clients.
+ io.ReaderAt
+ sr *io.SectionReader
+}
+
+func (s *Segment) Put32(b []byte, o binary.ByteOrder) int {
+ o.PutUint32(b[0*4:], uint32(s.LoadCmd))
+ o.PutUint32(b[1*4:], s.Len)
+ putAtMost16Bytes(b[2*4:], s.Name)
+ o.PutUint32(b[6*4:], uint32(s.Addr))
+ o.PutUint32(b[7*4:], uint32(s.Memsz))
+ o.PutUint32(b[8*4:], uint32(s.Offset))
+ o.PutUint32(b[9*4:], uint32(s.Filesz))
+ o.PutUint32(b[10*4:], s.Maxprot)
+ o.PutUint32(b[11*4:], s.Prot)
+ o.PutUint32(b[12*4:], s.Nsect)
+ o.PutUint32(b[13*4:], uint32(s.Flag))
+ return 14 * 4
+}
+
+func (s *Segment) Put64(b []byte, o binary.ByteOrder) int {
+ o.PutUint32(b[0*4:], uint32(s.LoadCmd))
+ o.PutUint32(b[1*4:], s.Len)
+ putAtMost16Bytes(b[2*4:], s.Name)
+ o.PutUint64(b[6*4+0*8:], s.Addr)
+ o.PutUint64(b[6*4+1*8:], s.Memsz)
+ o.PutUint64(b[6*4+2*8:], s.Offset)
+ o.PutUint64(b[6*4+3*8:], s.Filesz)
+ o.PutUint32(b[6*4+4*8:], s.Maxprot)
+ o.PutUint32(b[7*4+4*8:], s.Prot)
+ o.PutUint32(b[8*4+4*8:], s.Nsect)
+ o.PutUint32(b[9*4+4*8:], uint32(s.Flag))
+ return 10*4 + 4*8
+}
+
+// LoadCmdBytes is a command-tagged sequence of bytes.
+// This is used for Load Commands that are not (yet)
+// interesting to us, and to common up this behavior for
+// all those that are.
+type LoadCmdBytes struct {
+ LoadCmd
+ LoadBytes
+}
+
+type SectionHeader struct {
+ Name string
+ Seg string
+ Addr uint64
+ Size uint64
+ Offset uint32
+ Align uint32
+ Reloff uint32
+ Nreloc uint32
+ Flags SecFlags
+ Reserved1 uint32
+ Reserved2 uint32
+ Reserved3 uint32 // only present if original was 64-bit
+}
+
+// A Reloc represents a Mach-O relocation.
+type Reloc struct {
+ Addr uint32
+ Value uint32
+ // when Scattered == false && Extern == true, Value is the symbol number.
+ // when Scattered == false && Extern == false, Value is the section number.
+ // when Scattered == true, Value is the value that this reloc refers to.
+ Type uint8
+ Len uint8 // 0=byte, 1=word, 2=long, 3=quad
+ Pcrel bool
+ Extern bool // valid if Scattered == false
+ Scattered bool
+}
+
+type Section struct {
+ SectionHeader
+ Relocs []Reloc
+
+ // Embed ReaderAt for ReadAt method.
+ // Do not embed SectionReader directly
+ // to avoid having Read and Seek.
+ // If a client wants Read and Seek it must use
+ // Open() to avoid fighting over the seek offset
+ // with other clients.
+ io.ReaderAt
+ sr *io.SectionReader
+}
+
+func (s *Section) Put32(b []byte, o binary.ByteOrder) int {
+ putAtMost16Bytes(b[0:], s.Name)
+ putAtMost16Bytes(b[16:], s.Seg)
+ o.PutUint32(b[8*4:], uint32(s.Addr))
+ o.PutUint32(b[9*4:], uint32(s.Size))
+ o.PutUint32(b[10*4:], s.Offset)
+ o.PutUint32(b[11*4:], s.Align)
+ o.PutUint32(b[12*4:], s.Reloff)
+ o.PutUint32(b[13*4:], s.Nreloc)
+ o.PutUint32(b[14*4:], uint32(s.Flags))
+ o.PutUint32(b[15*4:], s.Reserved1)
+ o.PutUint32(b[16*4:], s.Reserved2)
+ a := 17 * 4
+ return a + s.PutRelocs(b[a:], o)
+}
+
+func (s *Section) Put64(b []byte, o binary.ByteOrder) int {
+ putAtMost16Bytes(b[0:], s.Name)
+ putAtMost16Bytes(b[16:], s.Seg)
+ o.PutUint64(b[8*4+0*8:], s.Addr)
+ o.PutUint64(b[8*4+1*8:], s.Size)
+ o.PutUint32(b[8*4+2*8:], s.Offset)
+ o.PutUint32(b[9*4+2*8:], s.Align)
+ o.PutUint32(b[10*4+2*8:], s.Reloff)
+ o.PutUint32(b[11*4+2*8:], s.Nreloc)
+ o.PutUint32(b[12*4+2*8:], uint32(s.Flags))
+ o.PutUint32(b[13*4+2*8:], s.Reserved1)
+ o.PutUint32(b[14*4+2*8:], s.Reserved2)
+ o.PutUint32(b[15*4+2*8:], s.Reserved3)
+ a := 16*4 + 2*8
+ return a + s.PutRelocs(b[a:], o)
+}
+
+func (s *Section) PutRelocs(b []byte, o binary.ByteOrder) int {
+ a := 0
+ for _, r := range s.Relocs {
+ var ri relocInfo
+ typ := uint32(r.Type) & (1<<4 - 1)
+ len := uint32(r.Len) & (1<<2 - 1)
+ pcrel := uint32(0)
+ if r.Pcrel {
+ pcrel = 1
+ }
+ ext := uint32(0)
+ if r.Extern {
+ ext = 1
+ }
+ switch {
+ case r.Scattered:
+ ri.Addr = r.Addr&(1<<24-1) | typ<<24 | len<<28 | 1<<31 | pcrel<<30
+ ri.Symnum = r.Value
+ case o == binary.LittleEndian:
+ ri.Addr = r.Addr
+ ri.Symnum = r.Value&(1<<24-1) | pcrel<<24 | len<<25 | ext<<27 | typ<<28
+ case o == binary.BigEndian:
+ ri.Addr = r.Addr
+ ri.Symnum = r.Value<<8 | pcrel<<7 | len<<5 | ext<<4 | typ
+ }
+ o.PutUint32(b, ri.Addr)
+ o.PutUint32(b[4:], ri.Symnum)
+ a += 8
+ b = b[8:]
+ }
+ return a
+}
+
+func putAtMost16Bytes(b []byte, n string) {
+ for i := range n { // at most 16 bytes
+ if i == 16 {
+ break
+ }
+ b[i] = n[i]
+ }
+}
+
+// A Symbol is a Mach-O 32-bit or 64-bit symbol table entry.
+type Symbol struct {
+ Name string
+ Type uint8
+ Sect uint8
+ Desc uint16
+ Value uint64
+}
+
+/*
+ * Mach-O reader
+ */
+
+// FormatError is returned by some operations if the data does
+// not have the correct format for an object file.
+type FormatError struct {
+ off int64
+ msg string
+}
+
+func formatError(off int64, format string, data ...interface{}) *FormatError {
+ return &FormatError{off, fmt.Sprintf(format, data...)}
+}
+
+func (e *FormatError) Error() string {
+ return e.msg + fmt.Sprintf(" in record at byte %#x", e.off)
+}
+
+func (e *FormatError) String() string {
+ return e.Error()
+}
+
+// DerivedCopy returns a modified copy of the TOC, with empty loads and sections,
+// and with the specified header type and flags.
+func (t *FileTOC) DerivedCopy(Type HdrType, Flags HdrFlags) *FileTOC {
+ h := t.FileHeader
+ h.NCommands, h.SizeCommands, h.Type, h.Flags = 0, 0, Type, Flags
+
+ return &FileTOC{FileHeader: h, ByteOrder: t.ByteOrder}
+}
+
+// TOCSize returns the size in bytes of the object file representation
+// of the header and Load Commands (including Segments and Sections, but
+// not their contents) at the beginning of a Mach-O file. This typically
+// overlaps the text segment in the object file.
+func (t *FileTOC) TOCSize() uint32 {
+ return t.HdrSize() + t.LoadSize()
+}
+
+// LoadAlign returns the required alignment of Load commands in a binary.
+// This is used to add padding for necessary alignment.
+func (t *FileTOC) LoadAlign() uint64 {
+ if t.Magic == Magic64 {
+ return 8
+ }
+ return 4
+}
+
+// SymbolSize returns the size in bytes of a Symbol (Nlist32 or Nlist64)
+func (t *FileTOC) SymbolSize() uint32 {
+ if t.Magic == Magic64 {
+ return uint32(unsafe.Sizeof(Nlist64{}))
+ }
+ return uint32(unsafe.Sizeof(Nlist32{}))
+}
+
+// HdrSize returns the size in bytes of the Macho header for a given
+// magic number (where the magic number has been appropriately byte-swapped).
+func (t *FileTOC) HdrSize() uint32 {
+ switch t.Magic {
+ case Magic32:
+ return fileHeaderSize32
+ case Magic64:
+ return fileHeaderSize64
+ case MagicFat:
+ panic("MagicFat not handled yet")
+ default:
+ panic(fmt.Sprintf("Unexpected magic number 0x%x, expected Mach-O object file", t.Magic))
+ }
+}
+
+// LoadSize returns the size of all the load commands in a file's table-of contents
+// (but not their associated data, e.g., sections and symbol tables)
+func (t *FileTOC) LoadSize() uint32 {
+ cmdsz := uint32(0)
+ for _, l := range t.Loads {
+ s := l.LoadSize(t)
+ cmdsz += s
+ }
+ return cmdsz
+}
+
+// FileSize returns the size in bytes of the header, load commands, and the
+// in-file contents of all the segments and sections included in those
+// load commands, accounting for their offsets within the file.
+func (t *FileTOC) FileSize() uint64 {
+ sz := uint64(t.LoadSize()) // ought to be contained in text segment, but just in case.
+ for _, l := range t.Loads {
+ if s, ok := l.(*Segment); ok {
+ if m := s.Offset + s.Filesz; m > sz {
+ sz = m
+ }
+ }
+ }
+ return sz
+}
+
+// Put writes the header and all load commands to buffer, using
+// the byte ordering specified in FileTOC t. For sections, this
+// writes the headers that come in-line with the segment Load commands,
+// but does not write the reference data for those sections.
+func (t *FileTOC) Put(buffer []byte) int {
+ next := t.FileHeader.Put(buffer, t.ByteOrder)
+ for _, l := range t.Loads {
+ if s, ok := l.(*Segment); ok {
+ switch t.Magic {
+ case Magic64:
+ next += s.Put64(buffer[next:], t.ByteOrder)
+ for i := uint32(0); i < s.Nsect; i++ {
+ c := t.Sections[i+s.Firstsect]
+ next += c.Put64(buffer[next:], t.ByteOrder)
+ }
+ case Magic32:
+ next += s.Put32(buffer[next:], t.ByteOrder)
+ for i := uint32(0); i < s.Nsect; i++ {
+ c := t.Sections[i+s.Firstsect]
+ next += c.Put32(buffer[next:], t.ByteOrder)
+ }
+ default:
+ panic(fmt.Sprintf("Unexpected magic number 0x%x", t.Magic))
+ }
+
+ } else {
+ next += l.Put(buffer[next:], t.ByteOrder)
+ }
+ }
+ return next
+}
+
+// UncompressedSize returns the size of the segment with its sections uncompressed, ignoring
+// its offset within the file. The returned size is rounded up to the power of two in align.
+func (s *Segment) UncompressedSize(t *FileTOC, align uint64) uint64 {
+ sz := uint64(0)
+ for j := uint32(0); j < s.Nsect; j++ {
+ c := t.Sections[j+s.Firstsect]
+ sz += c.UncompressedSize()
+ }
+ return (sz + align - 1) & uint64(-int64(align))
+}
+
+func (s *Section) UncompressedSize() uint64 {
+ if !strings.HasPrefix(s.Name, "__z") {
+ return s.Size
+ }
+ b := make([]byte, 12)
+ n, err := s.sr.ReadAt(b, 0)
+ if err != nil {
+ panic("Malformed object file")
+ }
+ if n != len(b) {
+ return s.Size
+ }
+ if string(b[:4]) == "ZLIB" {
+ return binary.BigEndian.Uint64(b[4:12])
+ }
+ return s.Size
+}
+
+func (s *Section) PutData(b []byte) {
+ bb := b[0:s.Size]
+ n, err := s.sr.ReadAt(bb, 0)
+ if err != nil || uint64(n) != s.Size {
+ panic("Malformed object file (ReadAt error)")
+ }
+}
+
+func (s *Section) PutUncompressedData(b []byte) {
+ if strings.HasPrefix(s.Name, "__z") {
+ bb := make([]byte, 12)
+ n, err := s.sr.ReadAt(bb, 0)
+ if err != nil {
+ panic("Malformed object file")
+ }
+ if n == len(bb) && string(bb[:4]) == "ZLIB" {
+ size := binary.BigEndian.Uint64(bb[4:12])
+ // Decompress starting at b[12:]
+ r, err := zlib.NewReader(io.NewSectionReader(s, 12, int64(size)-12))
+ if err != nil {
+ panic("Malformed object file (zlib.NewReader error)")
+ }
+ n, err := io.ReadFull(r, b[0:size])
+ if err != nil {
+ panic("Malformed object file (ReadFull error)")
+ }
+ if uint64(n) != size {
+ panic(fmt.Sprintf("PutUncompressedData, expected to read %d bytes, instead read %d", size, n))
+ }
+ if err := r.Close(); err != nil {
+ panic("Malformed object file (Close error)")
+ }
+ return
+ }
+ }
+ // Not compressed
+ s.PutData(b)
+}
+
+func (b LoadBytes) String() string {
+ s := "["
+ for i, a := range b {
+ if i > 0 {
+ s += " "
+ if len(b) > 48 && i >= 16 {
+ s += fmt.Sprintf("... (%d bytes)", len(b))
+ break
+ }
+ }
+ s += fmt.Sprintf("%x", a)
+ }
+ s += "]"
+ return s
+}
+
+func (b LoadBytes) Raw() []byte { return b }
+func (b LoadBytes) Copy() LoadBytes { return LoadBytes(append([]byte{}, b...)) }
+func (b LoadBytes) LoadSize(t *FileTOC) uint32 { return uint32(len(b)) }
+
+func (lc LoadCmd) Put(b []byte, o binary.ByteOrder) int {
+ panic(fmt.Sprintf("Put not implemented for %s", lc.String()))
+}
+
+func (s LoadCmdBytes) String() string {
+ return s.LoadCmd.String() + ": " + s.LoadBytes.String()
+}
+func (s LoadCmdBytes) Copy() LoadCmdBytes {
+ return LoadCmdBytes{LoadCmd: s.LoadCmd, LoadBytes: s.LoadBytes.Copy()}
+}
+
+func (s *SegmentHeader) String() string {
+ return fmt.Sprintf(
+ "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",
+ s.Name, s.Len, s.Addr, s.Memsz, s.Offset, s.Filesz, s.Maxprot, s.Prot, s.Nsect, s.Flag, s.Firstsect)
+}
+
+func (s *Segment) String() string {
+ return fmt.Sprintf(
+ "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",
+ s.Name, s.Len, s.Addr, s.Memsz, s.Offset, s.Filesz, s.Maxprot, s.Prot, s.Nsect, s.Flag, s.Firstsect)
+}
+
+// Data reads and returns the contents of the segment.
+func (s *Segment) Data() ([]byte, error) {
+ dat := make([]byte, s.sr.Size())
+ n, err := s.sr.ReadAt(dat, 0)
+ if n == len(dat) {
+ err = nil
+ }
+ return dat[0:n], err
+}
+
+func (s *Segment) Copy() *Segment {
+ r := &Segment{SegmentHeader: s.SegmentHeader}
+ return r
+}
+func (s *Segment) CopyZeroed() *Segment {
+ r := s.Copy()
+ r.Filesz = 0
+ r.Offset = 0
+ r.Nsect = 0
+ r.Firstsect = 0
+ if s.Command() == LcSegment64 {
+ r.Len = uint32(unsafe.Sizeof(Segment64{}))
+ } else {
+ r.Len = uint32(unsafe.Sizeof(Segment32{}))
+ }
+ return r
+}
+
+func (s *Segment) LoadSize(t *FileTOC) uint32 {
+ if s.Command() == LcSegment64 {
+ return uint32(unsafe.Sizeof(Segment64{})) + uint32(s.Nsect)*uint32(unsafe.Sizeof(Section64{}))
+ }
+ return uint32(unsafe.Sizeof(Segment32{})) + uint32(s.Nsect)*uint32(unsafe.Sizeof(Section32{}))
+}
+
+// Open returns a new ReadSeeker reading the segment.
+func (s *Segment) Open() io.ReadSeeker { return io.NewSectionReader(s.sr, 0, 1<<63-1) }
+
+// Data reads and returns the contents of the Mach-O section.
+func (s *Section) Data() ([]byte, error) {
+ dat := make([]byte, s.sr.Size())
+ n, err := s.sr.ReadAt(dat, 0)
+ if n == len(dat) {
+ err = nil
+ }
+ return dat[0:n], err
+}
+
+func (s *Section) Copy() *Section {
+ return &Section{SectionHeader: s.SectionHeader}
+}
+
+// Open returns a new ReadSeeker reading the Mach-O section.
+func (s *Section) Open() io.ReadSeeker { return io.NewSectionReader(s.sr, 0, 1<<63-1) }
+
+// A Dylib represents a Mach-O load dynamic library command.
+type Dylib struct {
+ DylibCmd
+ Name string
+ Time uint32
+ CurrentVersion uint32
+ CompatVersion uint32
+}
+
+func (s *Dylib) String() string { return "Dylib " + s.Name }
+func (s *Dylib) Copy() *Dylib {
+ r := *s
+ return &r
+}
+func (s *Dylib) LoadSize(t *FileTOC) uint32 {
+ return uint32(RoundUp(uint64(unsafe.Sizeof(DylibCmd{}))+uint64(len(s.Name)), t.LoadAlign()))
+}
+
+type Dylinker struct {
+ DylinkerCmd // shared by 3 commands, need the LoadCmd
+ Name string
+}
+
+func (s *Dylinker) String() string { return s.DylinkerCmd.LoadCmd.String() + " " + s.Name }
+func (s *Dylinker) Copy() *Dylinker {
+ return &Dylinker{DylinkerCmd: s.DylinkerCmd, Name: s.Name}
+}
+func (s *Dylinker) LoadSize(t *FileTOC) uint32 {
+ return uint32(RoundUp(uint64(unsafe.Sizeof(DylinkerCmd{}))+uint64(len(s.Name)), t.LoadAlign()))
+}
+
+// A Symtab represents a Mach-O symbol table command.
+type Symtab struct {
+ SymtabCmd
+ Syms []Symbol
+}
+
+func (s *Symtab) Put(b []byte, o binary.ByteOrder) int {
+ o.PutUint32(b[0*4:], uint32(s.LoadCmd))
+ o.PutUint32(b[1*4:], s.Len)
+ o.PutUint32(b[2*4:], s.Symoff)
+ o.PutUint32(b[3*4:], s.Nsyms)
+ o.PutUint32(b[4*4:], s.Stroff)
+ o.PutUint32(b[5*4:], s.Strsize)
+ return 6 * 4
+}
+
+func (s *Symtab) String() string { return fmt.Sprintf("Symtab %#v", s.SymtabCmd) }
+func (s *Symtab) Copy() *Symtab {
+ return &Symtab{SymtabCmd: s.SymtabCmd, Syms: append([]Symbol{}, s.Syms...)}
+}
+func (s *Symtab) LoadSize(t *FileTOC) uint32 {
+ return uint32(unsafe.Sizeof(SymtabCmd{}))
+}
+
+type LinkEditData struct {
+ LinkEditDataCmd
+}
+
+func (s *LinkEditData) String() string { return "LinkEditData " + s.LoadCmd.String() }
+func (s *LinkEditData) Copy() *LinkEditData {
+ return &LinkEditData{LinkEditDataCmd: s.LinkEditDataCmd}
+}
+func (s *LinkEditData) LoadSize(t *FileTOC) uint32 {
+ return uint32(unsafe.Sizeof(LinkEditDataCmd{}))
+}
+
+type Uuid struct {
+ UuidCmd
+}
+
+func (s *Uuid) String() string {
+ return fmt.Sprintf("Uuid %X-%X-%X-%X-%X",
+ s.Id[0:4], s.Id[4:6], s.Id[6:8], s.Id[8:10], s.Id[10:16])
+} // 8-4-4-4-12
+func (s *Uuid) Copy() *Uuid {
+ return &Uuid{UuidCmd: s.UuidCmd}
+}
+func (s *Uuid) LoadSize(t *FileTOC) uint32 {
+ return uint32(unsafe.Sizeof(UuidCmd{}))
+}
+func (s *Uuid) Put(b []byte, o binary.ByteOrder) int {
+ o.PutUint32(b[0*4:], uint32(s.LoadCmd))
+ o.PutUint32(b[1*4:], s.Len)
+ copy(b[2*4:], s.Id[0:])
+ return int(s.Len)
+}
+
+type DyldInfo struct {
+ DyldInfoCmd
+}
+
+func (s *DyldInfo) String() string { return "DyldInfo " + s.LoadCmd.String() }
+func (s *DyldInfo) Copy() *DyldInfo {
+ return &DyldInfo{DyldInfoCmd: s.DyldInfoCmd}
+}
+func (s *DyldInfo) LoadSize(t *FileTOC) uint32 {
+ return uint32(unsafe.Sizeof(DyldInfoCmd{}))
+}
+
+type EncryptionInfo struct {
+ EncryptionInfoCmd
+}
+
+func (s *EncryptionInfo) String() string { return "EncryptionInfo " + s.LoadCmd.String() }
+func (s *EncryptionInfo) Copy() *EncryptionInfo {
+ return &EncryptionInfo{EncryptionInfoCmd: s.EncryptionInfoCmd}
+}
+func (s *EncryptionInfo) LoadSize(t *FileTOC) uint32 {
+ return uint32(unsafe.Sizeof(EncryptionInfoCmd{}))
+}
+
+// A Dysymtab represents a Mach-O dynamic symbol table command.
+type Dysymtab struct {
+ DysymtabCmd
+ IndirectSyms []uint32 // indices into Symtab.Syms
+}
+
+func (s *Dysymtab) String() string { return fmt.Sprintf("Dysymtab %#v", s.DysymtabCmd) }
+func (s *Dysymtab) Copy() *Dysymtab {
+ return &Dysymtab{DysymtabCmd: s.DysymtabCmd, IndirectSyms: append([]uint32{}, s.IndirectSyms...)}
+}
+func (s *Dysymtab) LoadSize(t *FileTOC) uint32 {
+ return uint32(unsafe.Sizeof(DysymtabCmd{}))
+}
+
+// A Rpath represents a Mach-O rpath command.
+type Rpath struct {
+ LoadCmd
+ Path string
+}
+
+func (s *Rpath) String() string { return "Rpath " + s.Path }
+func (s *Rpath) Command() LoadCmd { return LcRpath }
+func (s *Rpath) Copy() *Rpath {
+ return &Rpath{Path: s.Path}
+}
+func (s *Rpath) LoadSize(t *FileTOC) uint32 {
+ return uint32(RoundUp(uint64(unsafe.Sizeof(RpathCmd{}))+uint64(len(s.Path)), t.LoadAlign()))
+}
+
+// Open opens the named file using os.Open and prepares it for use as a Mach-O binary.
+func Open(name string) (*File, error) {
+ f, err := os.Open(name)
+ if err != nil {
+ return nil, err
+ }
+ ff, err := NewFile(f)
+ if err != nil {
+ f.Close()
+ return nil, err
+ }
+ ff.closer = f
+ return ff, nil
+}
+
+// Close closes the File.
+// If the File was created using NewFile directly instead of Open,
+// Close has no effect.
+func (f *File) Close() error {
+ var err error
+ if f.closer != nil {
+ err = f.closer.Close()
+ f.closer = nil
+ }
+ return err
+}
+
+// NewFile creates a new File for accessing a Mach-O binary in an underlying reader.
+// The Mach-O binary is expected to start at position 0 in the ReaderAt.
+func NewFile(r io.ReaderAt) (*File, error) {
+ f := new(File)
+ sr := io.NewSectionReader(r, 0, 1<<63-1)
+
+ // Read and decode Mach magic to determine byte order, size.
+ // Magic32 and Magic64 differ only in the bottom bit.
+ var ident [4]byte
+ if _, err := r.ReadAt(ident[0:], 0); err != nil {
+ return nil, err
+ }
+ be := binary.BigEndian.Uint32(ident[0:])
+ le := binary.LittleEndian.Uint32(ident[0:])
+ switch Magic32 &^ 1 {
+ case be &^ 1:
+ f.ByteOrder = binary.BigEndian
+ f.Magic = be
+ case le &^ 1:
+ f.ByteOrder = binary.LittleEndian
+ f.Magic = le
+ default:
+ return nil, formatError(0, "invalid magic number be=0x%x, le=0x%x", be, le)
+ }
+
+ // Read entire file header.
+ if err := binary.Read(sr, f.ByteOrder, &f.FileHeader); err != nil {
+ return nil, err
+ }
+
+ // Then load commands.
+ offset := int64(fileHeaderSize32)
+ if f.Magic == Magic64 {
+ offset = fileHeaderSize64
+ }
+ dat := make([]byte, f.SizeCommands)
+ if _, err := r.ReadAt(dat, offset); err != nil {
+ return nil, err
+ }
+ f.Loads = make([]Load, f.NCommands)
+ bo := f.ByteOrder
+ for i := range f.Loads {
+ // Each load command begins with uint32 command and length.
+ if len(dat) < 8 {
+ return nil, formatError(offset, "command block too small, len(dat) = %d", len(dat))
+ }
+ cmd, siz := LoadCmd(bo.Uint32(dat[0:4])), bo.Uint32(dat[4:8])
+ if siz < 8 || siz > uint32(len(dat)) {
+ return nil, formatError(offset, "invalid command block size, len(dat)=%d, size=%d", len(dat), siz)
+ }
+ var cmddat []byte
+ cmddat, dat = dat[0:siz], dat[siz:]
+ offset += int64(siz)
+ var s *Segment
+ switch cmd {
+ default:
+ f.Loads[i] = LoadCmdBytes{LoadCmd(cmd), LoadBytes(cmddat)}
+
+ case LcUuid:
+ var hdr UuidCmd
+ b := bytes.NewReader(cmddat)
+ if err := binary.Read(b, bo, &hdr); err != nil {
+ return nil, err
+ }
+ l := &Uuid{UuidCmd: hdr}
+
+ f.Loads[i] = l
+
+ case LcRpath:
+ var hdr RpathCmd
+ b := bytes.NewReader(cmddat)
+ if err := binary.Read(b, bo, &hdr); err != nil {
+ return nil, err
+ }
+ l := &Rpath{LoadCmd: hdr.LoadCmd}
+ if hdr.Path >= uint32(len(cmddat)) {
+ return nil, formatError(offset, "invalid path in rpath command, len(cmddat)=%d, hdr.Path=%d", len(cmddat), hdr.Path)
+ }
+ l.Path = cstring(cmddat[hdr.Path:])
+ f.Loads[i] = l
+
+ case LcLoadDylinker, LcIdDylinker, LcDyldEnvironment:
+ var hdr DylinkerCmd
+ b := bytes.NewReader(cmddat)
+ if err := binary.Read(b, bo, &hdr); err != nil {
+ return nil, err
+ }
+ l := new(Dylinker)
+ if hdr.Name >= uint32(len(cmddat)) {
+ return nil, formatError(offset, "invalid name in dynamic linker command, hdr.Name=%d, len(cmddat)=%d", hdr.Name, len(cmddat))
+ }
+ l.Name = cstring(cmddat[hdr.Name:])
+ l.DylinkerCmd = hdr
+ f.Loads[i] = l
+
+ case LcDylib:
+ var hdr DylibCmd
+ b := bytes.NewReader(cmddat)
+ if err := binary.Read(b, bo, &hdr); err != nil {
+ return nil, err
+ }
+ l := new(Dylib)
+ if hdr.Name >= uint32(len(cmddat)) {
+ return nil, formatError(offset, "invalid name in dynamic library command, hdr.Name=%d, len(cmddat)=%d", hdr.Name, len(cmddat))
+ }
+ l.Name = cstring(cmddat[hdr.Name:])
+ l.Time = hdr.Time
+ l.CurrentVersion = hdr.CurrentVersion
+ l.CompatVersion = hdr.CompatVersion
+ f.Loads[i] = l
+
+ case LcSymtab:
+ var hdr SymtabCmd
+ b := bytes.NewReader(cmddat)
+ if err := binary.Read(b, bo, &hdr); err != nil {
+ return nil, err
+ }
+ strtab := make([]byte, hdr.Strsize)
+ if _, err := r.ReadAt(strtab, int64(hdr.Stroff)); err != nil {
+ return nil, err
+ }
+ var symsz int
+ if f.Magic == Magic64 {
+ symsz = 16
+ } else {
+ symsz = 12
+ }
+ symdat := make([]byte, int(hdr.Nsyms)*symsz)
+ if _, err := r.ReadAt(symdat, int64(hdr.Symoff)); err != nil {
+ return nil, err
+ }
+ st, err := f.parseSymtab(symdat, strtab, cmddat, &hdr, offset)
+ st.SymtabCmd = hdr
+ if err != nil {
+ return nil, err
+ }
+ f.Loads[i] = st
+ f.Symtab = st
+
+ case LcDysymtab:
+ var hdr DysymtabCmd
+ b := bytes.NewReader(cmddat)
+ if err := binary.Read(b, bo, &hdr); err != nil {
+ return nil, err
+ }
+ dat := make([]byte, hdr.Nindirectsyms*4)
+ if _, err := r.ReadAt(dat, int64(hdr.Indirectsymoff)); err != nil {
+ return nil, err
+ }
+ x := make([]uint32, hdr.Nindirectsyms)
+ if err := binary.Read(bytes.NewReader(dat), bo, x); err != nil {
+ return nil, err
+ }
+ st := new(Dysymtab)
+ st.DysymtabCmd = hdr
+ st.IndirectSyms = x
+ f.Loads[i] = st
+ f.Dysymtab = st
+
+ case LcSegment:
+ var seg32 Segment32
+ b := bytes.NewReader(cmddat)
+ if err := binary.Read(b, bo, &seg32); err != nil {
+ return nil, err
+ }
+ s = new(Segment)
+ s.LoadCmd = cmd
+ s.Len = siz
+ s.Name = cstring(seg32.Name[0:])
+ s.Addr = uint64(seg32.Addr)
+ s.Memsz = uint64(seg32.Memsz)
+ s.Offset = uint64(seg32.Offset)
+ s.Filesz = uint64(seg32.Filesz)
+ s.Maxprot = seg32.Maxprot
+ s.Prot = seg32.Prot
+ s.Nsect = seg32.Nsect
+ s.Flag = seg32.Flag
+ s.Firstsect = uint32(len(f.Sections))
+ f.Loads[i] = s
+ for i := 0; i < int(s.Nsect); i++ {
+ var sh32 Section32
+ if err := binary.Read(b, bo, &sh32); err != nil {
+ return nil, err
+ }
+ sh := new(Section)
+ sh.Name = cstring(sh32.Name[0:])
+ sh.Seg = cstring(sh32.Seg[0:])
+ sh.Addr = uint64(sh32.Addr)
+ sh.Size = uint64(sh32.Size)
+ sh.Offset = sh32.Offset
+ sh.Align = sh32.Align
+ sh.Reloff = sh32.Reloff
+ sh.Nreloc = sh32.Nreloc
+ sh.Flags = sh32.Flags
+ sh.Reserved1 = sh32.Reserve1
+ sh.Reserved2 = sh32.Reserve2
+ if err := f.pushSection(sh, r); err != nil {
+ return nil, err
+ }
+ }
+
+ case LcSegment64:
+ var seg64 Segment64
+ b := bytes.NewReader(cmddat)
+ if err := binary.Read(b, bo, &seg64); err != nil {
+ return nil, err
+ }
+ s = new(Segment)
+ s.LoadCmd = cmd
+ s.Len = siz
+ s.Name = cstring(seg64.Name[0:])
+ s.Addr = seg64.Addr
+ s.Memsz = seg64.Memsz
+ s.Offset = seg64.Offset
+ s.Filesz = seg64.Filesz
+ s.Maxprot = seg64.Maxprot
+ s.Prot = seg64.Prot
+ s.Nsect = seg64.Nsect
+ s.Flag = seg64.Flag
+ s.Firstsect = uint32(len(f.Sections))
+ f.Loads[i] = s
+ for i := 0; i < int(s.Nsect); i++ {
+ var sh64 Section64
+ if err := binary.Read(b, bo, &sh64); err != nil {
+ return nil, err
+ }
+ sh := new(Section)
+ sh.Name = cstring(sh64.Name[0:])
+ sh.Seg = cstring(sh64.Seg[0:])
+ sh.Addr = sh64.Addr
+ sh.Size = sh64.Size
+ sh.Offset = sh64.Offset
+ sh.Align = sh64.Align
+ sh.Reloff = sh64.Reloff
+ sh.Nreloc = sh64.Nreloc
+ sh.Flags = sh64.Flags
+ sh.Reserved1 = sh64.Reserve1
+ sh.Reserved2 = sh64.Reserve2
+ sh.Reserved3 = sh64.Reserve3
+ if err := f.pushSection(sh, r); err != nil {
+ return nil, err
+ }
+ }
+
+ case LcCodeSignature, LcSegmentSplitInfo, LcFunctionStarts,
+ LcDataInCode, LcDylibCodeSignDrs:
+ var hdr LinkEditDataCmd
+ b := bytes.NewReader(cmddat)
+
+ if err := binary.Read(b, bo, &hdr); err != nil {
+ return nil, err
+ }
+ l := new(LinkEditData)
+
+ l.LinkEditDataCmd = hdr
+ f.Loads[i] = l
+
+ case LcEncryptionInfo, LcEncryptionInfo64:
+ var hdr EncryptionInfoCmd
+ b := bytes.NewReader(cmddat)
+
+ if err := binary.Read(b, bo, &hdr); err != nil {
+ return nil, err
+ }
+ l := new(EncryptionInfo)
+
+ l.EncryptionInfoCmd = hdr
+ f.Loads[i] = l
+
+ case LcDyldInfo, LcDyldInfoOnly:
+ var hdr DyldInfoCmd
+ b := bytes.NewReader(cmddat)
+
+ if err := binary.Read(b, bo, &hdr); err != nil {
+ return nil, err
+ }
+ l := new(DyldInfo)
+
+ l.DyldInfoCmd = hdr
+ f.Loads[i] = l
+ }
+ if s != nil {
+ s.sr = io.NewSectionReader(r, int64(s.Offset), int64(s.Filesz))
+ s.ReaderAt = s.sr
+ }
+ if f.Loads[i].LoadSize(&f.FileTOC) != siz {
+ 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())
+ panic("oops")
+ }
+ }
+ return f, nil
+}
+
+func (f *File) parseSymtab(symdat, strtab, cmddat []byte, hdr *SymtabCmd, offset int64) (*Symtab, error) {
+ bo := f.ByteOrder
+ symtab := make([]Symbol, hdr.Nsyms)
+ b := bytes.NewReader(symdat)
+ for i := range symtab {
+ var n Nlist64
+ if f.Magic == Magic64 {
+ if err := binary.Read(b, bo, &n); err != nil {
+ return nil, err
+ }
+ } else {
+ var n32 Nlist32
+ if err := binary.Read(b, bo, &n32); err != nil {
+ return nil, err
+ }
+ n.Name = n32.Name
+ n.Type = n32.Type
+ n.Sect = n32.Sect
+ n.Desc = n32.Desc
+ n.Value = uint64(n32.Value)
+ }
+ sym := &symtab[i]
+ if n.Name >= uint32(len(strtab)) {
+ return nil, formatError(offset, "invalid name in symbol table, n.Name=%d, len(strtab)=%d", n.Name, len(strtab))
+ }
+ sym.Name = cstring(strtab[n.Name:])
+ sym.Type = n.Type
+ sym.Sect = n.Sect
+ sym.Desc = n.Desc
+ sym.Value = n.Value
+ }
+ st := new(Symtab)
+ st.Syms = symtab
+ return st, nil
+}
+
+type relocInfo struct {
+ Addr uint32
+ Symnum uint32
+}
+
+func (f *File) pushSection(sh *Section, r io.ReaderAt) error {
+ f.Sections = append(f.Sections, sh)
+ sh.sr = io.NewSectionReader(r, int64(sh.Offset), int64(sh.Size))
+ sh.ReaderAt = sh.sr
+
+ if sh.Nreloc > 0 {
+ reldat := make([]byte, int(sh.Nreloc)*8)
+ if _, err := r.ReadAt(reldat, int64(sh.Reloff)); err != nil {
+ return err
+ }
+ b := bytes.NewReader(reldat)
+
+ bo := f.ByteOrder
+
+ sh.Relocs = make([]Reloc, sh.Nreloc)
+ for i := range sh.Relocs {
+ rel := &sh.Relocs[i]
+
+ var ri relocInfo
+ if err := binary.Read(b, bo, &ri); err != nil {
+ return err
+ }
+
+ if ri.Addr&(1<<31) != 0 { // scattered
+ rel.Addr = ri.Addr & (1<<24 - 1)
+ rel.Type = uint8((ri.Addr >> 24) & (1<<4 - 1))
+ rel.Len = uint8((ri.Addr >> 28) & (1<<2 - 1))
+ rel.Pcrel = ri.Addr&(1<<30) != 0
+ rel.Value = ri.Symnum
+ rel.Scattered = true
+ } else {
+ switch bo {
+ case binary.LittleEndian:
+ rel.Addr = ri.Addr
+ rel.Value = ri.Symnum & (1<<24 - 1)
+ rel.Pcrel = ri.Symnum&(1<<24) != 0
+ rel.Len = uint8((ri.Symnum >> 25) & (1<<2 - 1))
+ rel.Extern = ri.Symnum&(1<<27) != 0
+ rel.Type = uint8((ri.Symnum >> 28) & (1<<4 - 1))
+ case binary.BigEndian:
+ rel.Addr = ri.Addr
+ rel.Value = ri.Symnum >> 8
+ rel.Pcrel = ri.Symnum&(1<<7) != 0
+ rel.Len = uint8((ri.Symnum >> 5) & (1<<2 - 1))
+ rel.Extern = ri.Symnum&(1<<4) != 0
+ rel.Type = uint8(ri.Symnum & (1<<4 - 1))
+ default:
+ panic("unreachable")
+ }
+ }
+ }
+ }
+
+ return nil
+}
+
+func cstring(b []byte) string {
+ i := bytes.IndexByte(b, 0)
+ if i == -1 {
+ i = len(b)
+ }
+ return string(b[0:i])
+}
+
+// Segment returns the first Segment with the given name, or nil if no such segment exists.
+func (f *File) Segment(name string) *Segment {
+ for _, l := range f.Loads {
+ if s, ok := l.(*Segment); ok && s.Name == name {
+ return s
+ }
+ }
+ return nil
+}
+
+// Section returns the first section with the given name, or nil if no such
+// section exists.
+func (f *File) Section(name string) *Section {
+ for _, s := range f.Sections {
+ if s.Name == name {
+ return s
+ }
+ }
+ return nil
+}
+
+// DWARF returns the DWARF debug information for the Mach-O file.
+func (f *File) DWARF() (*dwarf.Data, error) {
+ dwarfSuffix := func(s *Section) string {
+ switch {
+ case strings.HasPrefix(s.Name, "__debug_"):
+ return s.Name[8:]
+ case strings.HasPrefix(s.Name, "__zdebug_"):
+ return s.Name[9:]
+ default:
+ return ""
+ }
+
+ }
+ sectionData := func(s *Section) ([]byte, error) {
+ b, err := s.Data()
+ if err != nil && uint64(len(b)) < s.Size {
+ return nil, err
+ }
+
+ if len(b) >= 12 && string(b[:4]) == "ZLIB" {
+ dlen := binary.BigEndian.Uint64(b[4:12])
+ dbuf := make([]byte, dlen)
+ r, err := zlib.NewReader(bytes.NewBuffer(b[12:]))
+ if err != nil {
+ return nil, err
+ }
+ if _, err := io.ReadFull(r, dbuf); err != nil {
+ return nil, err
+ }
+ if err := r.Close(); err != nil {
+ return nil, err
+ }
+ b = dbuf
+ }
+ return b, nil
+ }
+
+ // There are many other DWARF sections, but these
+ // are the ones the debug/dwarf package uses.
+ // Don't bother loading others.
+ var dat = map[string][]byte{"abbrev": nil, "info": nil, "str": nil, "line": nil, "ranges": nil}
+ for _, s := range f.Sections {
+ suffix := dwarfSuffix(s)
+ if suffix == "" {
+ continue
+ }
+ if _, ok := dat[suffix]; !ok {
+ continue
+ }
+ b, err := sectionData(s)
+ if err != nil {
+ return nil, err
+ }
+ dat[suffix] = b
+ }
+
+ d, err := dwarf.New(dat["abbrev"], nil, nil, dat["info"], dat["line"], nil, dat["ranges"], dat["str"])
+ if err != nil {
+ return nil, err
+ }
+
+ // Look for DWARF4 .debug_types sections.
+ for i, s := range f.Sections {
+ suffix := dwarfSuffix(s)
+ if suffix != "types" {
+ continue
+ }
+
+ b, err := sectionData(s)
+ if err != nil {
+ return nil, err
+ }
+
+ err = d.AddTypes(fmt.Sprintf("types-%d", i), b)
+ if err != nil {
+ return nil, err
+ }
+ }
+
+ return d, nil
+}
+
+// ImportedSymbols returns the names of all symbols
+// referred to by the binary f that are expected to be
+// satisfied by other libraries at dynamic load time.
+func (f *File) ImportedSymbols() ([]string, error) {
+ if f.Dysymtab == nil || f.Symtab == nil {
+ return nil, formatError(0, "missing symbol table, f.Dsymtab=%v, f.Symtab=%v", f.Dysymtab, f.Symtab)
+ }
+
+ st := f.Symtab
+ dt := f.Dysymtab
+ var all []string
+ for _, s := range st.Syms[dt.Iundefsym : dt.Iundefsym+dt.Nundefsym] {
+ all = append(all, s.Name)
+ }
+ return all, nil
+}
+
+// ImportedLibraries returns the paths of all libraries
+// referred to by the binary f that are expected to be
+// linked with the binary at dynamic link time.
+func (f *File) ImportedLibraries() ([]string, error) {
+ var all []string
+ for _, l := range f.Loads {
+ if lib, ok := l.(*Dylib); ok {
+ all = append(all, lib.Name)
+ }
+ }
+ return all, nil
+}
+
+func RoundUp(x, align uint64) uint64 {
+ return uint64((x + align - 1) & -align)
+}
projects / dotfiles / .git / blobdiff