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go/cmd/splitdwarf/internal/macho/macho.go
David Chase d30e00c240 splitdwarf: initial working commit
splitdwarf osxMachoFile [ osxDsymFile ]

splitdwarf takes an executable produced by go build as input,
and uncompresses and copies the DWARF segment into a separate
file in the way that is expected by OSX-hosted tools
(lldb and ports of gdb).
If osxDsymFile is not named explicitly, the default of
"<osxMachoFile>.dSYM/Contents/Resources/DWARF/<osxMachoFile>"
is used instead, with directories created as needed.

If the input file contains no UUID, then one is created by
hashing non-DWARF segment contents, and added to the
executable. This is necessary because gdb and lldb both
expect matching UUIDs to be present in the executable
and its debugging symbols.

Includes a modified version of debug/macho, with additional
definitions and the ability to write segments, sections, and
some MachO load commands added.

Change-Id: Ia5b0e289260f72bbca392cdf2c7c0a75e3ca40e5
Reviewed-on: https://go-review.googlesource.com/c/143357
Reviewed-by: Austin Clements <austin@google.com>
2019-01-09 16:56:30 +00:00

469 lines
11 KiB
Go

// 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.
// Mach-O header data structures
// http://developer.apple.com/mac/library/documentation/DeveloperTools/Conceptual/MachORuntime/Reference/reference.html
package macho
import (
"encoding/binary"
"strconv"
)
// A FileHeader represents a Mach-O file header.
type FileHeader struct {
Magic uint32
Cpu Cpu
SubCpu uint32
Type HdrType
NCommands uint32 // number of load commands
SizeCommands uint32 // size of all the load commands, not including this header.
Flags HdrFlags
}
func (h *FileHeader) Put(b []byte, o binary.ByteOrder) int {
o.PutUint32(b[0:], h.Magic)
o.PutUint32(b[4:], uint32(h.Cpu))
o.PutUint32(b[8:], h.SubCpu)
o.PutUint32(b[12:], uint32(h.Type))
o.PutUint32(b[16:], h.NCommands)
o.PutUint32(b[20:], h.SizeCommands)
o.PutUint32(b[24:], uint32(h.Flags))
if h.Magic == Magic32 {
return 28
}
o.PutUint32(b[28:], 0)
return 32
}
const (
fileHeaderSize32 = 7 * 4
fileHeaderSize64 = 8 * 4
)
const (
Magic32 uint32 = 0xfeedface
Magic64 uint32 = 0xfeedfacf
MagicFat uint32 = 0xcafebabe
)
type HdrFlags uint32
type SegFlags uint32
type SecFlags uint32
// A HdrType is the Mach-O file type, e.g. an object file, executable, or dynamic library.
type HdrType uint32
const ( // SNAKE_CASE to CamelCase translation from C names
MhObject HdrType = 1
MhExecute HdrType = 2
MhCore HdrType = 4
MhDylib HdrType = 6
MhBundle HdrType = 8
MhDsym HdrType = 0xa
)
var typeStrings = []intName{
{uint32(MhObject), "Obj"},
{uint32(MhExecute), "Exec"},
{uint32(MhDylib), "Dylib"},
{uint32(MhBundle), "Bundle"},
{uint32(MhDsym), "Dsym"},
}
func (t HdrType) String() string { return stringName(uint32(t), typeStrings, false) }
func (t HdrType) GoString() string { return stringName(uint32(t), typeStrings, true) }
// A Cpu is a Mach-O cpu type.
type Cpu uint32
const cpuArch64 = 0x01000000
const (
Cpu386 Cpu = 7
CpuAmd64 Cpu = Cpu386 | cpuArch64
CpuArm Cpu = 12
CpuArm64 Cpu = CpuArm | cpuArch64
CpuPpc Cpu = 18
CpuPpc64 Cpu = CpuPpc | cpuArch64
)
var cpuStrings = []intName{
{uint32(Cpu386), "Cpu386"},
{uint32(CpuAmd64), "CpuAmd64"},
{uint32(CpuArm), "CpuArm"},
{uint32(CpuArm64), "CpuArm64"},
{uint32(CpuPpc), "CpuPpc"},
{uint32(CpuPpc64), "CpuPpc64"},
}
func (i Cpu) String() string { return stringName(uint32(i), cpuStrings, false) }
func (i Cpu) GoString() string { return stringName(uint32(i), cpuStrings, true) }
// A LoadCmd is a Mach-O load command.
type LoadCmd uint32
func (c LoadCmd) Command() LoadCmd { return c }
const ( // SNAKE_CASE to CamelCase translation from C names
// Note 3 and 8 are obsolete
LcSegment LoadCmd = 0x1
LcSymtab LoadCmd = 0x2
LcThread LoadCmd = 0x4
LcUnixthread LoadCmd = 0x5 // thread+stack
LcDysymtab LoadCmd = 0xb
LcDylib LoadCmd = 0xc // load dylib command
LcIdDylib LoadCmd = 0xd // dynamically linked shared lib ident
LcLoadDylinker LoadCmd = 0xe // load a dynamic linker
LcIdDylinker LoadCmd = 0xf // id dylinker command (not load dylinker command)
LcSegment64 LoadCmd = 0x19
LcUuid LoadCmd = 0x1b
LcCodeSignature LoadCmd = 0x1d
LcSegmentSplitInfo LoadCmd = 0x1e
LcRpath LoadCmd = 0x8000001c
LcEncryptionInfo LoadCmd = 0x21
LcDyldInfo LoadCmd = 0x22
LcDyldInfoOnly LoadCmd = 0x80000022
LcVersionMinMacosx LoadCmd = 0x24
LcVersionMinIphoneos LoadCmd = 0x25
LcFunctionStarts LoadCmd = 0x26
LcDyldEnvironment LoadCmd = 0x27
LcMain LoadCmd = 0x80000028 // replacement for UnixThread
LcDataInCode LoadCmd = 0x29 // There are non-instructions in text
LcSourceVersion LoadCmd = 0x2a // Source version used to build binary
LcDylibCodeSignDrs LoadCmd = 0x2b
LcEncryptionInfo64 LoadCmd = 0x2c
LcVersionMinTvos LoadCmd = 0x2f
LcVersionMinWatchos LoadCmd = 0x30
)
var cmdStrings = []intName{
{uint32(LcSegment), "LoadCmdSegment"},
{uint32(LcThread), "LoadCmdThread"},
{uint32(LcUnixthread), "LoadCmdUnixThread"},
{uint32(LcDylib), "LoadCmdDylib"},
{uint32(LcIdDylib), "LoadCmdIdDylib"},
{uint32(LcLoadDylinker), "LoadCmdLoadDylinker"},
{uint32(LcIdDylinker), "LoadCmdIdDylinker"},
{uint32(LcSegment64), "LoadCmdSegment64"},
{uint32(LcUuid), "LoadCmdUuid"},
{uint32(LcRpath), "LoadCmdRpath"},
{uint32(LcDyldEnvironment), "LoadCmdDyldEnv"},
{uint32(LcMain), "LoadCmdMain"},
{uint32(LcDataInCode), "LoadCmdDataInCode"},
{uint32(LcSourceVersion), "LoadCmdSourceVersion"},
{uint32(LcDyldInfo), "LoadCmdDyldInfo"},
{uint32(LcDyldInfoOnly), "LoadCmdDyldInfoOnly"},
{uint32(LcVersionMinMacosx), "LoadCmdMinOsx"},
{uint32(LcFunctionStarts), "LoadCmdFunctionStarts"},
}
func (i LoadCmd) String() string { return stringName(uint32(i), cmdStrings, false) }
func (i LoadCmd) GoString() string { return stringName(uint32(i), cmdStrings, true) }
type (
// A Segment32 is a 32-bit Mach-O segment load command.
Segment32 struct {
LoadCmd
Len uint32
Name [16]byte
Addr uint32
Memsz uint32
Offset uint32
Filesz uint32
Maxprot uint32
Prot uint32
Nsect uint32
Flag SegFlags
}
// A Segment64 is a 64-bit Mach-O segment load command.
Segment64 struct {
LoadCmd
Len uint32
Name [16]byte
Addr uint64
Memsz uint64
Offset uint64
Filesz uint64
Maxprot uint32
Prot uint32
Nsect uint32
Flag SegFlags
}
// A SymtabCmd is a Mach-O symbol table command.
SymtabCmd struct {
LoadCmd
Len uint32
Symoff uint32
Nsyms uint32
Stroff uint32
Strsize uint32
}
// A DysymtabCmd is a Mach-O dynamic symbol table command.
DysymtabCmd struct {
LoadCmd
Len uint32
Ilocalsym uint32
Nlocalsym uint32
Iextdefsym uint32
Nextdefsym uint32
Iundefsym uint32
Nundefsym uint32
Tocoffset uint32
Ntoc uint32
Modtaboff uint32
Nmodtab uint32
Extrefsymoff uint32
Nextrefsyms uint32
Indirectsymoff uint32
Nindirectsyms uint32
Extreloff uint32
Nextrel uint32
Locreloff uint32
Nlocrel uint32
}
// A DylibCmd is a Mach-O load dynamic library command.
DylibCmd struct {
LoadCmd
Len uint32
Name uint32
Time uint32
CurrentVersion uint32
CompatVersion uint32
}
// A DylinkerCmd is a Mach-O load dynamic linker or environment command.
DylinkerCmd struct {
LoadCmd
Len uint32
Name uint32
}
// A RpathCmd is a Mach-O rpath command.
RpathCmd struct {
LoadCmd
Len uint32
Path uint32
}
// A Thread is a Mach-O thread state command.
Thread struct {
LoadCmd
Len uint32
Type uint32
Data []uint32
}
// LC_DYLD_INFO, LC_DYLD_INFO_ONLY
DyldInfoCmd struct {
LoadCmd
Len uint32
RebaseOff, RebaseLen uint32 // file offset and length; data contains segment indices
BindOff, BindLen uint32 // file offset and length; data contains segment indices
WeakBindOff, WeakBindLen uint32 // file offset and length
LazyBindOff, LazyBindLen uint32 // file offset and length
ExportOff, ExportLen uint32 // file offset and length
}
// LC_CODE_SIGNATURE, LC_SEGMENT_SPLIT_INFO, LC_FUNCTION_STARTS, LC_DATA_IN_CODE, LC_DYLIB_CODE_SIGN_DRS
LinkEditDataCmd struct {
LoadCmd
Len uint32
DataOff, DataLen uint32 // file offset and length
}
// LC_ENCRYPTION_INFO, LC_ENCRYPTION_INFO_64
EncryptionInfoCmd struct {
LoadCmd
Len uint32
CryptOff, CryptLen uint32 // file offset and length
CryptId uint32
}
UuidCmd struct {
LoadCmd
Len uint32
Id [16]byte
}
// TODO Commands below not fully supported yet.
EntryPointCmd struct {
LoadCmd
Len uint32
EntryOff uint64 // file offset
StackSize uint64 // if not zero, initial stack size
}
NoteCmd struct {
LoadCmd
Len uint32
Name [16]byte
Offset, Filesz uint64 // file offset and length
}
)
const (
FlagNoUndefs HdrFlags = 0x1
FlagIncrLink HdrFlags = 0x2
FlagDyldLink HdrFlags = 0x4
FlagBindAtLoad HdrFlags = 0x8
FlagPrebound HdrFlags = 0x10
FlagSplitSegs HdrFlags = 0x20
FlagLazyInit HdrFlags = 0x40
FlagTwoLevel HdrFlags = 0x80
FlagForceFlat HdrFlags = 0x100
FlagNoMultiDefs HdrFlags = 0x200
FlagNoFixPrebinding HdrFlags = 0x400
FlagPrebindable HdrFlags = 0x800
FlagAllModsBound HdrFlags = 0x1000
FlagSubsectionsViaSymbols HdrFlags = 0x2000
FlagCanonical HdrFlags = 0x4000
FlagWeakDefines HdrFlags = 0x8000
FlagBindsToWeak HdrFlags = 0x10000
FlagAllowStackExecution HdrFlags = 0x20000
FlagRootSafe HdrFlags = 0x40000
FlagSetuidSafe HdrFlags = 0x80000
FlagNoReexportedDylibs HdrFlags = 0x100000
FlagPIE HdrFlags = 0x200000
FlagDeadStrippableDylib HdrFlags = 0x400000
FlagHasTLVDescriptors HdrFlags = 0x800000
FlagNoHeapExecution HdrFlags = 0x1000000
FlagAppExtensionSafe HdrFlags = 0x2000000
)
// A Section32 is a 32-bit Mach-O section header.
type Section32 struct {
Name [16]byte
Seg [16]byte
Addr uint32
Size uint32
Offset uint32
Align uint32
Reloff uint32
Nreloc uint32
Flags SecFlags
Reserve1 uint32
Reserve2 uint32
}
// A Section64 is a 64-bit Mach-O section header.
type Section64 struct {
Name [16]byte
Seg [16]byte
Addr uint64
Size uint64
Offset uint32
Align uint32
Reloff uint32
Nreloc uint32
Flags SecFlags
Reserve1 uint32
Reserve2 uint32
Reserve3 uint32
}
// An Nlist32 is a Mach-O 32-bit symbol table entry.
type Nlist32 struct {
Name uint32
Type uint8
Sect uint8
Desc uint16
Value uint32
}
// An Nlist64 is a Mach-O 64-bit symbol table entry.
type Nlist64 struct {
Name uint32
Type uint8
Sect uint8
Desc uint16
Value uint64
}
func (n *Nlist64) Put64(b []byte, o binary.ByteOrder) uint32 {
o.PutUint32(b[0:], n.Name)
b[4] = byte(n.Type)
b[5] = byte(n.Sect)
o.PutUint16(b[6:], n.Desc)
o.PutUint64(b[8:], n.Value)
return 8 + 8
}
func (n *Nlist64) Put32(b []byte, o binary.ByteOrder) uint32 {
o.PutUint32(b[0:], n.Name)
b[4] = byte(n.Type)
b[5] = byte(n.Sect)
o.PutUint16(b[6:], n.Desc)
o.PutUint32(b[8:], uint32(n.Value))
return 8 + 4
}
// Regs386 is the Mach-O 386 register structure.
type Regs386 struct {
AX uint32
BX uint32
CX uint32
DX uint32
DI uint32
SI uint32
BP uint32
SP uint32
SS uint32
FLAGS uint32
IP uint32
CS uint32
DS uint32
ES uint32
FS uint32
GS uint32
}
// RegsAMD64 is the Mach-O AMD64 register structure.
type RegsAMD64 struct {
AX uint64
BX uint64
CX uint64
DX uint64
DI uint64
SI uint64
BP uint64
SP uint64
R8 uint64
R9 uint64
R10 uint64
R11 uint64
R12 uint64
R13 uint64
R14 uint64
R15 uint64
IP uint64
FLAGS uint64
CS uint64
FS uint64
GS uint64
}
type intName struct {
i uint32
s string
}
func stringName(i uint32, names []intName, goSyntax bool) string {
for _, n := range names {
if n.i == i {
if goSyntax {
return "macho." + n.s
}
return n.s
}
}
return "0x" + strconv.FormatUint(uint64(i), 16)
}