runc/mount/pivotroot.go

35 lines
743 B
Go

// +build linux
package mount
import (
"fmt"
"io/ioutil"
"os"
"path/filepath"
"syscall"
)
func PivotRoot(rootfs string) error {
pivotDir, err := ioutil.TempDir(rootfs, ".pivot_root")
if err != nil {
return fmt.Errorf("can't create pivot_root dir %s, error %v", pivotDir, err)
}
if err := syscall.PivotRoot(rootfs, pivotDir); err != nil {
return fmt.Errorf("pivot_root %s", err)
}
if err := syscall.Chdir("/"); err != nil {
return fmt.Errorf("chdir / %s", err)
}
// path to pivot dir now changed, update
pivotDir = filepath.Join("/", filepath.Base(pivotDir))
if err := syscall.Unmount(pivotDir, syscall.MNT_DETACH); err != nil {
return fmt.Errorf("unmount pivot_root dir %s", err)
}
return os.Remove(pivotDir)
}