VSFixedFileInfo.go

// Thanks:
// http://stackoverflow.com/questions/12396665/c-library-to-read-exe-version-from-linux#answer-12486703

package main

import (
	"encoding/binary"
	"errors"
	"os"
)

func readWord(file *os.File, off int64) int64 {
	file.Seek(off, 0)
	var n uint16
	binary.Read(file, binary.LittleEndian, &n)
	return int64(n)
}

func readDword(file *os.File, off int64) int64 {
	file.Seek(off, 0)
	var n uint32
	binary.Read(file, binary.LittleEndian, &n)
	return int64(n)
}

func pad(x int64) int64 {
	return (x + 3) & 0xFFFFFFFC
}

func equals(file *os.File, off int64, value string) bool {
	b := make([]byte, len(value))
	file.ReadAt(b, off)
	return string(b) == value
}

func findVersion(file *os.File) (ptr int64, err error) {
	if !equals(file, 0, "MZ") {
		return 0, errors.New("No MZ_HEADER")
	}

	pe := readWord(file, 0x3C)
	if !equals(file, pe, "PE") {
		return 0, errors.New("No PE_HEADER")
	}

	coff := pe + 4
	numSections := readWord(file, coff+2)
	optHeaderSize := readWord(file, coff+16)
	if numSections == 0 || optHeaderSize == 0 {
		return 0, errors.New("No opt header")
	}

	optHeader := coff + 20
	if readWord(file, optHeader) != 0x10b {
		return 0, errors.New("no optional header magic")
	}

	dataDir := optHeader + 96
	vaRes := readDword(file, dataDir+8*2)
	secTable := optHeader + optHeaderSize

	for i := 0; i < int(numSections); i++ {
		sec := secTable + 40*int64(i)
		if !equals(file, sec, ".rsrc") {
			continue
		}
		vaSec := readDword(file, sec+12)
		raw := readDword(file, sec+20)

		resSec := raw + (vaRes - vaSec)

		numNamed := readWord(file, resSec+12)
		numId := readWord(file, resSec+14)
		//	print("CHECK ", numNamed, " ", numId, "\n")

		for j := 0; j < int(numNamed+numId); j++ {
			// resSec is a IMAGE_RESOURCE_DIRECTORY followed by an array of
			// IMAGE_RESOURCE_DIRECTORY_ENTRY
			res := resSec + 16 + 8*int64(j)
			name := readDword(file, res)
			if name != 16 {
				continue
			}
			offs := readDword(file, res+4)
			if offs&0x80000000 == 0 {
				return 0, errors.New("no dir resource")
			}
			// verDir is another IMAGE_RESOURCE_DIRECTORY and
			// IMAGE_RESOURCE_DIRECTORY_ENTRY array
			verDir := resSec + (offs & 0x7FFFFFFF)

			numNamed = readWord(file, verDir+12)
			numId = readWord(file, verDir+14)
			if numNamed == 0 && numId == 0 {
				return 0, errors.New("resource empty")
			}
			res = verDir + 16
			offs = readDword(file, res+4)
			if offs&0x80000000 == 0 {
				return 0, errors.New("no dir ressource")
			}

			// and yet another IMAGE_RESOURCE_DIRECTORY, etc.
			verDir = resSec + (offs & 0x7FFFFFFF)
			numNamed = readWord(file, verDir+12)
			numId = readWord(file, verDir+14)
			if numNamed == 0 && numId == 0 {
				return 0, errors.New("resource empty")
			}
			res = verDir + 16
			offs = readDword(file, res+4)
			if offs&0x80000000 != 0 {
				return 0, errors.New("no dir resource")
			}
			verDir = resSec + offs

			verVa := readDword(file, verDir)
			//verSize := readDword(file, verDir+4)

			verPtr := raw + (verVa - vaSec)
			return verPtr, nil
		}
		return 0, errors.New("")
	}
	return 0, errors.New("")
}

func recParse(file *os.File, ptr int64, offs int64, version *uint64) int64 {
	len := readWord(file, ptr+offs)
	offs += 2
	valLen := readWord(file, ptr+offs)
	offs += 2
	vtype := readWord(file, ptr+offs)
	offs += 2

	info := []byte{}
	for i := 0; i < 200; i++ {
		c := readWord(file, ptr+offs)
		if c == 0 {
			break
		}
		offs += 2
		info = append(info, byte(c))
	}
	offs = pad(offs)
	if vtype != 0 { // TEXT
		value := []byte{}
		for i := 0; i < int(valLen); i++ {
			c := readWord(file, ptr+offs)
			offs += 2
			value = append(value, byte(c))
		}
	} else {
		if string(info) == "VS_VERSION_INFO" {
			fixed := ptr + offs
			//dwSignature := readDword(file, fixed+4)
			//dwStrucVersion := readDword(file, fixed+8)
			//dwFileVersionMS := readDword(file, fixed+12)
			//dwFileVersionLS := readDword(file, fixed+16)
			dwProductVersionMS := readDword(file, fixed+12)
			dwProductVersionLS := readDword(file, fixed+16)
			//dwFileFlagsMask := readDword(file, fixed+28)
			//dwFileFlags := readDword(file, fixed+32)
			//dwFileOS := readDword(file, fixed+36)
			//dwFileType := readDword(file, fixed+40)
			//dwFileSubtype := readDword(file, fixed+44)
			//dwFileDateMS := readDword(file, fixed+48)
			//dwFileDateLS := readDword(file, fixed+52)
			*version = uint64(dwProductVersionMS<<32) | uint64(dwProductVersionLS)
		}
		offs += valLen
	}
	for offs < len {
		offs = recParse(file, ptr, offs, version)
	}
	return pad(offs)
}

func parseVersion(file *os.File, ptr int64) (version uint64) {
	recParse(file, ptr, 0, &version)
	return version
}

func ReadVersion(path string) (version Version) {
	file, _ := os.Open(path)
	defer file.Close()

	ptr, err := findVersion(file)
	if err != nil {
		return
	}

	ver := parseVersion(file, ptr)

	version.Major = uint16(ver >> 0x30)
	version.Minor = uint16(ver >> 0x20)
	version.Release = uint16(ver >> 0x10)
	version.Build = uint16(ver >> 0x00)
	return
}