Golang exec.Command函数代码示例

// IsLikelyNotMountPoint determines whether a path is a mountpoint by calling findmnt
// in the host's root mount namespace.
func (n *NsenterMounter) IsLikelyNotMountPoint(file string) (bool, error) {
	file, err := filepath.Abs(file)
	if err != nil {
		return true, err
	}

	args := []string{"--mount=/rootfs/proc/1/ns/mnt", "--", n.absHostPath("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 {
		glog.Errorf("Failed to nsenter mount, return file doesn't exist: %v", err)
		// If the command itself is correct, then if we encountered error
		// then most likely this means that the directory does not exist.
		return true, os.ErrNotExist
	}
	strOut := strings.TrimSuffix(string(out), "\n")

	glog.V(5).Infof("IsLikelyNotMountPoint findmnt output: %v", strOut)
	if strOut == file {
		return false, nil
	}

	return true, nil
}

// IsLikelyNotMountPoint determines whether a path is a mountpoint by calling findmnt
// in the host's root mount namespace.
func (n *NsenterMounter) IsLikelyNotMountPoint(file string) (bool, error) {
	file, err := filepath.Abs(file)
	if err != nil {
		return true, err
	}

	args := []string{"--mount=/rootfs/proc/1/ns/mnt", "--", n.absHostPath("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 {
		glog.V(2).Infof("Failed findmnt command: %v", err)
		// Different operating systems behave differently for paths which are not mount points.
		// On older versions (e.g. 2.20.1) we'd get error, on newer ones (e.g. 2.26.2) we'd get "/".
		// It's safer to assume that it's not a mount point.
		return true, nil
	}
	strOut := strings.TrimSuffix(string(out), "\n")

	glog.V(5).Infof("IsLikelyNotMountPoint findmnt output: %v", strOut)
	if strOut == file {
		return false, nil
	}

	return true, nil
}

// doNsenterMount nsenters the host's mount namespace and performs the
// requested mount.
func (n *NsenterMounter) doNsenterMount(source, target, fstype string, options []string) error {
	glog.V(5).Infof("nsenter Mounting %s %s %s %v", source, target, fstype, options)
	args := n.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 of mounting %s to %s: %v", source, target, 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
}

// IsLikelyNotMountPoint determines whether a path is a mountpoint by calling findmnt
// in the host's root mount namespace.
func (n *NsenterMounter) IsLikelyNotMountPoint(file string) (bool, error) {
	file, err := filepath.Abs(file)
	if err != nil {
		return true, err
	}

	// Check the directory exists
	if _, err = os.Stat(file); os.IsNotExist(err) {
		glog.V(5).Infof("findmnt: directory %s does not exist", file)
		return true, err
	}
	// Add --first-only option: since we are testing for the absense of a mountpoint, it is sufficient to get only
	// the first of multiple possible mountpoints using --first-only.
	// Also add fstype output to make sure that the output of target file will give the full path
	// TODO: Need more refactoring for this function. Track the solution with issue #26996
	args := []string{"--mount=/rootfs/proc/1/ns/mnt", "--", n.absHostPath("findmnt"), "-o", "target,fstype", "--noheadings", "--first-only", "--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 {
		glog.V(2).Infof("Failed findmnt command for path %s: %v", file, err)
		// Different operating systems behave differently for paths which are not mount points.
		// On older versions (e.g. 2.20.1) we'd get error, on newer ones (e.g. 2.26.2) we'd get "/".
		// It's safer to assume that it's not a mount point.
		return true, nil
	}
	mountTarget := strings.Split(string(out), " ")[0]
	mountTarget = strings.TrimSuffix(mountTarget, "\n")
	glog.V(5).Infof("IsLikelyNotMountPoint findmnt output for path %s: %v:", file, mountTarget)

	if mountTarget == file {
		glog.V(5).Infof("IsLikelyNotMountPoint: %s is a mount point", file)
		return false, nil
	}
	glog.V(5).Infof("IsLikelyNotMountPoint: %s is not a mount point", file)
	return true, nil
}

// IsLikelyNotMountPoint determines whether a path is a mountpoint by calling findmnt
// in the host's root mount namespace.
func (n *NsenterMounter) IsLikelyNotMountPoint(file string) (bool, error) {
	file, err := filepath.Abs(file)
	if err != nil {
		return true, err
	}

	args := []string{"--mount=/rootfs/proc/1/ns/mnt", "--", n.absHostPath("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 true, nil
	}
	strOut := strings.TrimSuffix(string(out), "\n")

	glog.V(5).Infof("IsLikelyNotMountPoint findmnt output: %v", strOut)
	if strOut == file {
		return false, nil
	}

	return true, nil
}