main.go

package main

import (
	"archive/tar"
	"flag"
	"log"
	"os"

	"github.com/sophaskins/efs2tar/efs"
	"github.com/sophaskins/efs2tar/sgi"
)

func main() {
	inputPath := flag.String("in", "", "the file to be read as an efs filesystem")
	outputPath := flag.String("out", "", "the file to written to as a tar file")
	flag.Parse()
	file, err := os.Open(*inputPath)
	if err != nil {
		log.Fatal(err)
	}

	b := make([]byte, 51200)
	_, err = file.Read(b)
	if err != nil {
		log.Fatal(err)
	}

	outputFile, err := os.OpenFile(*outputPath, os.O_RDWR|os.O_TRUNC|os.O_CREATE, 0755)
	if err != nil {
		log.Fatal(err)
	}
	tw := tar.NewWriter(outputFile)

	vh := sgi.NewVolumeHeader(b)
	p := vh.Partitions[7]
	fs := efs.NewFilesystem(file, p.Blocks, p.First)

	fs.WalkFilesystem(buildTarCallback(tw, fs))
	tw.Close()
}

func buildTarCallback(tw *tar.Writer, fs *efs.Filesystem) func(efs.Inode, string) {
	return func(in efs.Inode, path string) {
		if path == "" {
			return
		}

		if in.Type() == efs.FileTypeDirectory {
			hdr := &tar.Header{
				Name:     path,
				Mode:     0755,
				Typeflag: tar.TypeDir,
			}
			if err := tw.WriteHeader(hdr); err != nil {
				log.Fatal(err)
			}
		} else if in.Type() == efs.FileTypeRegular {
			contents := fs.FileContents(in)
			hdr := &tar.Header{
				Name: path,
				Mode: 0755,
				Size: int64(len(contents)),
			}
			if err := tw.WriteHeader(hdr); err != nil {
				log.Fatal(err)
			}
			if _, err := tw.Write([]byte(contents)); err != nil {
				log.Fatal(err)
			}
		} else if in.Type() == efs.FileTypeSymlink {
			contents := fs.FileContents(in)
			hdr := &tar.Header{
				Name:     path,
				Linkname: string(contents[:int64(len(contents))]),
				Typeflag: tar.TypeSymlink,
			}
			if err := tw.WriteHeader(hdr); err != nil {
				log.Fatal(err)
			}
		}
	}
}