1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
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"
NEWTIME NamespaceType = "NEWTIME"
)
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"
case NEWTIME:
return "time"
}
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
}
// We don't need to use /proc/thread-self here because the list of
// namespace types is unrelated to the thread. This lets us avoid having to
// do runtime.LockOSThread.
_, 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,
NEWTIME,
}
}
// 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
}
|
