| 39 | } |
| 40 | |
| 41 | func copyFS(newRoot string) error { |
| 42 | // find the device of the root filesystem so we can avoid changing filesystem |
| 43 | info, err := os.Stat("/") |
| 44 | if err != nil { |
| 45 | return err |
| 46 | } |
| 47 | stat := info.Sys().(*syscall.Stat_t) |
| 48 | rootDev := stat.Dev |
| 49 | |
| 50 | if err = unix.Mount("rootfs", newRoot, "tmpfs", 0, ""); err != nil { |
| 51 | return err |
| 52 | } |
| 53 | |
| 54 | // copy directory tree first |
| 55 | if err := filepath.Walk("/", func(path string, info os.FileInfo, err error) error { |
| 56 | if err != nil { |
| 57 | return err |
| 58 | } |
| 59 | // skip non directories |
| 60 | if !info.Mode().IsDir() { |
| 61 | return nil |
| 62 | } |
| 63 | dest := filepath.Join(newRoot, path) |
| 64 | // create the directory |
| 65 | if path == "/" { |
| 66 | // the mountpoint already exists but may have wrong mode, metadata |
| 67 | if err := os.Chmod(newRoot, info.Mode()); err != nil { |
| 68 | return err |
| 69 | } |
| 70 | } else { |
| 71 | if err := os.Mkdir(dest, info.Mode()); err != nil { |
| 72 | return err |
| 73 | } |
| 74 | } |
| 75 | if err := copyMetadata(info, dest); err != nil { |
| 76 | return err |
| 77 | } |
| 78 | // skip recurse into other filesystems |
| 79 | stat := info.Sys().(*syscall.Stat_t) |
| 80 | if rootDev != stat.Dev { |
| 81 | return filepath.SkipDir |
| 82 | } |
| 83 | return nil |
| 84 | }); err != nil { |
| 85 | return err |
| 86 | } |
| 87 | |
| 88 | buf := make([]byte, 32768) |
| 89 | |
| 90 | // now move files |
| 91 | if err := filepath.Walk("/", func(path string, info os.FileInfo, err error) error { |
| 92 | if err != nil { |
| 93 | return err |
| 94 | } |
| 95 | // skip other filesystems |
| 96 | stat := info.Sys().(*syscall.Stat_t) |
| 97 | if rootDev != stat.Dev && info.Mode().IsDir() { |
| 98 | return filepath.SkipDir |