Flattened package hierarchy

src/macho/MachO.go

@@ -0,0 +1,124 @@
+package macho
+
+import (
+	"bytes"
+	"encoding/binary"
+	"io"
+
+	"git.akyoto.dev/cli/q/src/config"
+	"git.akyoto.dev/cli/q/src/exe"
+)
+
+// MachO is the executable format used on MacOS.
+type MachO struct {
+	Header
+	PageZero   Segment64
+	CodeHeader Segment64
+	DataHeader Segment64
+	UnixThread Thread
+}
+
+// Write writes the Mach-O format to the given writer.
+func Write(writer io.Writer, code []byte, data []byte) {
+	const (
+		SizeCommands = Segment64Size*3 + ThreadSize
+		HeaderEnd    = HeaderSize + SizeCommands
+	)
+
+	var (
+		codeStart, codePadding = exe.Align(HeaderEnd, config.Align)
+		dataStart, dataPadding = exe.Align(codeStart+len(code), config.Align)
+	)
+
+	m := &MachO{
+		Header: Header{
+			Magic:             0xFEEDFACF,
+			Architecture:      CPU_X86_64,
+			MicroArchitecture: 3 | 0x80000000,
+			Type:              TypeExecute,
+			NumCommands:       4,
+			SizeCommands:      SizeCommands,
+			Flags:             FlagNoUndefs | FlagNoHeapExecution,
+			Reserved:          0,
+		},
+		PageZero: Segment64{
+			LoadCommand:  LcSegment64,
+			Length:       72,
+			Name:         [16]byte{'_', '_', 'P', 'A', 'G', 'E', 'Z', 'E', 'R', 'O'},
+			Address:      0,
+			SizeInMemory: config.BaseAddress,
+			Offset:       0,
+			SizeInFile:   0,
+			NumSections:  0,
+			Flag:         0,
+			MaxProt:      0,
+			InitProt:     0,
+		},
+		CodeHeader: Segment64{
+			LoadCommand:  LcSegment64,
+			Length:       Segment64Size,
+			Name:         [16]byte{'_', '_', 'T', 'E', 'X', 'T'},
+			Address:      config.BaseAddress,
+			SizeInMemory: uint64(codeStart + len(code)),
+			Offset:       0,
+			SizeInFile:   uint64(codeStart + len(code)),
+			NumSections:  0,
+			Flag:         0,
+			MaxProt:      ProtReadable | ProtExecutable,
+			InitProt:     ProtReadable | ProtExecutable,
+		},
+		DataHeader: Segment64{
+			LoadCommand:  LcSegment64,
+			Length:       Segment64Size,
+			Name:         [16]byte{'_', '_', 'D', 'A', 'T', 'A'},
+			Address:      uint64(config.BaseAddress + dataStart),
+			SizeInMemory: uint64(len(data)),
+			Offset:       uint64(dataStart),
+			SizeInFile:   uint64(len(data)),
+			NumSections:  0,
+			Flag:         0,
+			MaxProt:      ProtReadable,
+			InitProt:     ProtReadable,
+		},
+		UnixThread: Thread{
+			LoadCommand: LcUnixthread,
+			Len:         ThreadSize,
+			Type:        0x4,
+			Data: [43]uint32{
+				42,
+				0, 0,
+				0, 0,
+				0, 0,
+				0, 0,
+				0, 0,
+				0, 0,
+				0, 0,
+				0, 0,
+				0, 0,
+				0, 0,
+				0, 0,
+				0, 0,
+				0, 0,
+				0, 0,
+				0, 0,
+				0, 0,
+				config.BaseAddress + config.CodeOffset, 0,
+				0, 0,
+				0, 0,
+				0, 0,
+				0, 0,
+			},
+		},
+	}
+
+	binary.Write(writer, binary.LittleEndian, &m.Header)
+	binary.Write(writer, binary.LittleEndian, &m.PageZero)
+	binary.Write(writer, binary.LittleEndian, &m.CodeHeader)
+	binary.Write(writer, binary.LittleEndian, &m.DataHeader)
+	binary.Write(writer, binary.LittleEndian, &m.UnixThread)
+
+	writer.Write(bytes.Repeat([]byte{0x00}, int(codePadding)))
+	writer.Write(code)
+	writer.Write(bytes.Repeat([]byte{0x00}, int(dataPadding)))
+	writer.Write(data)
+}