refactor: Decompose syscalls into pkg, start adding utility commands

cmd/stfs-archive/main.go

@@ -0,0 +1,165 @@
+package main
+
+//go:generate sh -c "mkdir -p ../../pkg/api/proto/v1 && protoc --go_out=paths=source_relative,plugins=grpc:../../pkg/api/proto/v1 -I=../../api/proto/v1 ../../api/proto/v1/*.proto"
+
+import (
+	"archive/tar"
+	"bufio"
+	"flag"
+	"io"
+	"io/fs"
+	"log"
+	"os"
+	"path/filepath"
+	"strconv"
+	"syscall"
+	"time"
+
+	"github.com/pojntfx/stfs/pkg/controllers"
+	"golang.org/x/sys/unix"
+)
+
+const (
+	stfsVersionPAX = "STFS.Version"
+	stfsVersion    = 1
+
+	stfsActionPAX    = "STFS.Action"
+	stfsActionCreate = "CREATE"
+	stfsActionUpdate = "UPDATE"
+	stfsActionDelete = "DELETE"
+
+	stfsReplacesPAX = "STFS.Replaces"
+)
+
+func main() {
+	file := flag.String("file", "/dev/nst0", "File (tape drive or tar file) to open")
+	dir := flag.String("dir", ".", "Directory to add to the file")
+	recordSize := flag.Int("recordSize", 20, "Amount of 512-bit blocks per record")
+	overwrite := flag.Bool("overwrite", false, "Whether to start writing from the current position instead of from the end of the tape")
+
+	flag.Parse()
+
+	isRegular := true
+	stat, err := os.Stat(*file)
+	if err == nil {
+		isRegular = stat.Mode().IsRegular()
+	} else {
+		if os.IsNotExist(err) {
+			isRegular = true
+		} else {
+			panic(err)
+		}
+	}
+
+	var f *os.File
+	if isRegular {
+		if *overwrite {
+			f, err = os.OpenFile(*file, os.O_WRONLY|os.O_CREATE, 0600)
+			if err != nil {
+				panic(err)
+			}
+		} else {
+			f, err = os.OpenFile(*file, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
+			if err != nil {
+				panic(err)
+			}
+		}
+
+		// No need to go to end manually due to `os.O_APPEND`
+	} else {
+		f, err = os.OpenFile(*file, os.O_APPEND|os.O_WRONLY, os.ModeCharDevice)
+		if err != nil {
+			panic(err)
+		}
+
+		if !*overwrite {
+			// Go to end of tape
+			if err := controllers.GoToEndOfTape(f); err != nil {
+				panic(err)
+			}
+		}
+	}
+	defer f.Close()
+
+	var tw *tar.Writer
+	if isRegular {
+		tw = tar.NewWriter(f)
+	} else {
+		bw := bufio.NewWriterSize(f, controllers.BlockSize**recordSize)
+		tw = tar.NewWriter(bw)
+	}
+	defer tw.Close()
+
+	if err := filepath.Walk(*dir, func(path string, info fs.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		link := ""
+		if info.Mode()&os.ModeSymlink == os.ModeSymlink {
+			if link, err = os.Readlink(path); err != nil {
+				return err
+			}
+		}
+
+		hdr, err := tar.FileInfoHeader(info, link)
+		if err != nil {
+			return err
+		}
+
+		var unixStat syscall.Stat_t
+		if err := syscall.Stat(path, &unixStat); err != nil {
+			return err
+		}
+
+		mtimesec, mtimensec := unixStat.Mtim.Unix()
+		atimesec, atimensec := unixStat.Atim.Unix()
+		ctimesec, ctimensec := unixStat.Ctim.Unix()
+
+		hdr.ModTime = time.Unix(mtimesec, mtimensec)
+		hdr.AccessTime = time.Unix(atimesec, atimensec)
+		hdr.ChangeTime = time.Unix(ctimesec, ctimensec)
+
+		hdr.Devmajor = int64(unix.Major(unixStat.Dev))
+		hdr.Devminor = int64(unix.Minor(unixStat.Dev))
+
+		hdr.Name = path
+		hdr.PAXRecords = map[string]string{
+			stfsVersionPAX:  strconv.Itoa(stfsVersion),
+			stfsActionPAX:   stfsActionUpdate,
+			stfsReplacesPAX: "",
+		}
+		hdr.Format = tar.FormatPAX
+
+		log.Println(hdr)
+
+		if err := tw.WriteHeader(hdr); err != nil {
+			return err
+		}
+
+		if !info.Mode().IsRegular() {
+			return nil
+		}
+
+		file, err := os.Open(path)
+		if err != nil {
+			return err
+		}
+		defer file.Close()
+
+		if isRegular {
+			if _, err := io.Copy(tw, file); err != nil {
+				return err
+			}
+		} else {
+			buf := make([]byte, controllers.BlockSize**recordSize)
+			if _, err := io.CopyBuffer(tw, file, buf); err != nil {
+				return err
+			}
+		}
+
+		return nil
+	}); err != nil {
+		panic(err)
+	}
+}