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