mirror of https://github.com/docker/cli.git
128 lines
2.4 KiB
Go
128 lines
2.4 KiB
Go
// +build linux freebsd
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package configs
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import (
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"fmt"
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"os"
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"sync"
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)
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const (
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NEWNET NamespaceType = "NEWNET"
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NEWPID NamespaceType = "NEWPID"
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NEWNS NamespaceType = "NEWNS"
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NEWUTS NamespaceType = "NEWUTS"
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NEWIPC NamespaceType = "NEWIPC"
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NEWUSER NamespaceType = "NEWUSER"
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)
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var (
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nsLock sync.Mutex
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supportedNamespaces = make(map[NamespaceType]bool)
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)
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// NsName converts the namespace type to its filename
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func NsName(ns NamespaceType) string {
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switch ns {
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case NEWNET:
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return "net"
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case NEWNS:
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return "mnt"
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case NEWPID:
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return "pid"
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case NEWIPC:
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return "ipc"
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case NEWUSER:
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return "user"
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case NEWUTS:
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return "uts"
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}
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return ""
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}
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// IsNamespaceSupported returns whether a namespace is available or
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// not
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func IsNamespaceSupported(ns NamespaceType) bool {
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nsLock.Lock()
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defer nsLock.Unlock()
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supported, ok := supportedNamespaces[ns]
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if ok {
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return supported
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}
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nsFile := NsName(ns)
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// if the namespace type is unknown, just return false
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if nsFile == "" {
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return false
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}
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_, err := os.Stat(fmt.Sprintf("/proc/self/ns/%s", nsFile))
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// a namespace is supported if it exists and we have permissions to read it
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supported = err == nil
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supportedNamespaces[ns] = supported
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return supported
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}
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func NamespaceTypes() []NamespaceType {
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return []NamespaceType{
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NEWNET,
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NEWPID,
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NEWNS,
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NEWUTS,
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NEWIPC,
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NEWUSER,
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}
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}
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// Namespace defines configuration for each namespace. It specifies an
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// alternate path that is able to be joined via setns.
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type Namespace struct {
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Type NamespaceType `json:"type"`
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Path string `json:"path"`
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}
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func (n *Namespace) GetPath(pid int) string {
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if n.Path != "" {
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return n.Path
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}
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return fmt.Sprintf("/proc/%d/ns/%s", pid, NsName(n.Type))
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}
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func (n *Namespaces) Remove(t NamespaceType) bool {
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i := n.index(t)
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if i == -1 {
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return false
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}
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*n = append((*n)[:i], (*n)[i+1:]...)
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return true
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}
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func (n *Namespaces) Add(t NamespaceType, path string) {
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i := n.index(t)
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if i == -1 {
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*n = append(*n, Namespace{Type: t, Path: path})
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return
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}
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(*n)[i].Path = path
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}
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func (n *Namespaces) index(t NamespaceType) int {
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for i, ns := range *n {
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if ns.Type == t {
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return i
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}
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}
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return -1
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}
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func (n *Namespaces) Contains(t NamespaceType) bool {
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return n.index(t) != -1
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}
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func (n *Namespaces) PathOf(t NamespaceType) string {
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i := n.index(t)
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if i == -1 {
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return ""
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}
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return (*n)[i].Path
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}
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