138 lines
3.1 KiB
Go
138 lines
3.1 KiB
Go
package main
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import (
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"encoding/binary"
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"errors"
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"flag"
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"fmt"
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"io"
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"io/ioutil"
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"log"
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"os"
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"path/filepath"
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"strings"
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"syscall"
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)
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var (
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perm = flag.String("perm", "/perm", "new val for perm")
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gloaderHome = "/perm/gloader"
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)
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func main() {
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flag.Parse()
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gloaderHome = filepath.Join(*perm, "gloader")
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os.MkdirAll(gloaderHome, 0777)
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err := mount()
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if err != nil {
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log.Println(err)
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os.Exit(1)
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}
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d := newDownloader()
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d.DataDir = filepath.Join(gloaderHome, "data")
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d.Start("tcp", ":8844")
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}
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func mount() error {
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var (
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partUUIDb []byte
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partUUID string
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dev string
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err error
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dataStat os.FileInfo
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dataDir = filepath.Join(gloaderHome, "data")
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)
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partUUIDb, err = ioutil.ReadFile(filepath.Join(gloaderHome, "partition"))
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partUUID = strings.TrimSpace(string(partUUIDb))
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if err != nil || partUUID == "" {
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return nil
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}
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dataStat, err = os.Stat(dataDir)
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if err != nil {
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if errors.Is(err, os.ErrNotExist) {
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err = os.MkdirAll(dataDir, 0o755)
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if err != nil {
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return fmt.Errorf("error creating datadir: %w", err)
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}
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dataStat, err = os.Stat(dataDir)
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if err != nil {
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return fmt.Errorf("error mounting datadir: %w", err)
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}
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} else {
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return fmt.Errorf("error mounting datadir: %w", err)
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}
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}
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if dataStat.IsDir() {
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var folder *os.File
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folder, err = os.Open(dataDir)
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if err != nil {
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return fmt.Errorf("error mounting datadir: %w", err)
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}
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_, err = folder.Readdir(1)
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if errors.Is(err, io.EOF) {
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fmt.Printf("mount %s %s", partUUID, dataDir)
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dev, err = findPartUUID(partUUID)
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if err != nil {
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return fmt.Errorf("error mounting datadir: %w", err)
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}
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err = syscall.Mount(dev, dataDir, "ext4", 0, "")
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if err != nil {
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return fmt.Errorf("error mounting datadir: %w", err)
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}
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return nil
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}
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return fmt.Errorf("error mounting datadir: %w", err)
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}
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return fmt.Errorf("error mounting datadir: data dir %s is not a directory", dataDir)
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}
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func findPartUUID(uuid string) (string, error) {
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var dev string
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err := filepath.Walk("/sys/block", func(path string, info os.FileInfo, err error) error {
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if err != nil {
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log.Printf("findPartUUID: %v", err)
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return nil
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}
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if info.Mode()&os.ModeSymlink == 0 {
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return nil
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}
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devname := "/dev/" + filepath.Base(path)
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f, err := os.Open(devname)
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if err != nil {
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log.Printf("findPartUUID: %v", err)
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return nil
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}
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defer f.Close()
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if _, err := f.Seek(440, io.SeekStart); err != nil {
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var se syscall.Errno
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if errors.As(err, &se) && se == syscall.EINVAL {
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// Seek()ing empty loop devices results in EINVAL.
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return nil
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}
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log.Printf("findPartUUID: %v(%T)", err, err.(*os.PathError).Err)
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return nil
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}
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var diskSig struct {
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ID uint32
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Trailer uint16
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}
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if err := binary.Read(f, binary.LittleEndian, &diskSig); err != nil {
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log.Printf("findPartUUID: %v", err)
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return nil
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}
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if fmt.Sprintf("%08x", diskSig.ID) == uuid && diskSig.Trailer == 0 {
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dev = devname
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// TODO: abort early with sentinel error code
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return nil
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}
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return nil
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})
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if err != nil {
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return "", err
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}
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if dev == "" {
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return "", fmt.Errorf("PARTUUID=%s not found", uuid)
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}
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return dev, nil
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}
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