daeab40b45
1. Currently, Unmount() call takes a burden to parse the whole nine yards of /proc/self/mountinfo to figure out whether the given mount point is mounted or not (and returns an error in case parsing fails somehow). Instead, let's just call umount() and ignore EINVAL, which results in the same behavior, but much better performance. This also introduces a slight change: in case target does not exist, the appropriate error (ENOENT) is returned -- document that. 2. As Unmount() is always used with MNT_DETACH flag, let's drop the flags argument. This way, the only reason of EINVAL returned from umount(2) can only be "target is not mounted". 3. While at it, remove the 'containerdmount' alias from the package. Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
126 lines
3.2 KiB
Go
126 lines
3.2 KiB
Go
/*
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Copyright 2017 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package sandbox
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import (
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"os"
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"sync"
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cnins "github.com/containernetworking/plugins/pkg/ns"
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"github.com/docker/docker/pkg/symlink"
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"github.com/pkg/errors"
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osinterface "github.com/containerd/cri/pkg/os"
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)
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// ErrClosedNetNS is the error returned when network namespace is closed.
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var ErrClosedNetNS = errors.New("network namespace is closed")
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// NetNS holds network namespace for sandbox
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type NetNS struct {
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sync.Mutex
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ns cnins.NetNS
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closed bool
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restored bool
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}
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// NewNetNS creates a network namespace for the sandbox
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func NewNetNS() (*NetNS, error) {
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netns, err := cnins.NewNS()
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if err != nil {
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return nil, errors.Wrap(err, "failed to setup network namespace")
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}
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n := new(NetNS)
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n.ns = netns
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return n, nil
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}
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// LoadNetNS loads existing network namespace. It returns ErrClosedNetNS
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// if the network namespace has already been closed.
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func LoadNetNS(path string) (*NetNS, error) {
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ns, err := cnins.GetNS(path)
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if err != nil {
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if _, ok := err.(cnins.NSPathNotExistErr); ok {
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return nil, ErrClosedNetNS
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}
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if _, ok := err.(cnins.NSPathNotNSErr); ok {
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// Do best effort cleanup.
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os.RemoveAll(path) // nolint: errcheck
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return nil, ErrClosedNetNS
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}
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return nil, errors.Wrap(err, "failed to load network namespace")
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}
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return &NetNS{ns: ns, restored: true}, nil
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}
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// Remove removes network namepace if it exists and not closed. Remove is idempotent,
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// meaning it might be invoked multiple times and provides consistent result.
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func (n *NetNS) Remove() error {
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n.Lock()
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defer n.Unlock()
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if !n.closed {
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err := n.ns.Close()
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if err != nil {
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return errors.Wrap(err, "failed to close network namespace")
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}
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n.closed = true
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}
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if n.restored {
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path := n.ns.Path()
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// Check netns existence.
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if _, err := os.Stat(path); err != nil {
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if os.IsNotExist(err) {
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return nil
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}
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return errors.Wrap(err, "failed to stat netns")
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}
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path, err := symlink.FollowSymlinkInScope(path, "/")
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if err != nil {
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return errors.Wrap(err, "failed to follow symlink")
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}
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if err := osinterface.Unmount(path); err != nil && !os.IsNotExist(err) {
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return errors.Wrap(err, "failed to umount netns")
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}
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if err := os.RemoveAll(path); err != nil {
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return errors.Wrap(err, "failed to remove netns")
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}
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n.restored = false
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}
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return nil
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}
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// Closed checks whether the network namespace has been closed.
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func (n *NetNS) Closed() bool {
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n.Lock()
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defer n.Unlock()
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return n.closed && !n.restored
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}
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// GetPath returns network namespace path for sandbox container
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func (n *NetNS) GetPath() string {
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n.Lock()
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defer n.Unlock()
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return n.ns.Path()
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}
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// GetNs returns the network namespace handle
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func (n *NetNS) GetNs() cnins.NetNS {
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n.Lock()
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defer n.Unlock()
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return n.ns
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}
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