// doNsenterMount nsenters the host's mount namespace and performs the
// requested mount.
func doNsenterMount(source, target, fstype string, options []string) error {
glog.V(5).Infof("nsenter Mounting %s %s %s %v", source, target, fstype, options)
args := makeNsenterArgs(source, target, fstype, options)
glog.V(5).Infof("Mount command: %v %v", nsenterPath, args)
exec := exec.New()
outputBytes, err := exec.Command(nsenterPath, args...).CombinedOutput()
if len(outputBytes) != 0 {
glog.V(5).Infof("Output from mount command: %v", string(outputBytes))
}
return err
}
// Unmount runs umount(8) in the host's mount namespace.
func (*NsenterMounter) Unmount(target string) error {
args := []string{
"--mount=/rootfs/proc/1/ns/mnt",
"/usr/bin/umount",
target,
}
glog.V(5).Infof("Unmount command: %v %v", nsenterPath, args)
exec := exec.New()
outputBytes, err := exec.Command(nsenterPath, args...).CombinedOutput()
if len(outputBytes) != 0 {
glog.V(5).Infof("Output from mount command: %v", string(outputBytes))
}
return err
}
// IsMountPoint determines whether a path is a mountpoint by calling findmnt
// in the host's root mount namespace.
func (*NsenterMounter) IsMountPoint(file string) (bool, error) {
file, err := filepath.Abs(file)
if err != nil {
return false, err
}
args := []string{"--mount=/rootfs/proc/1/ns/mnt", "/usr/bin/findmnt", "-o", "target", "--noheadings", "--target", file}
glog.V(5).Infof("findmnt command: %v %v", nsenterPath, args)
exec := exec.New()
out, err := exec.Command(nsenterPath, args...).CombinedOutput()
if err != nil {
// If findmnt didn't run, just claim it's not a mount point.
return false, nil
}
strOut := strings.TrimSuffix(string(out), "\n")
glog.V(5).Infof("IsMountPoint findmnt output: %v", strOut)
if strOut == file {
return true, nil
}
return false, nil
}