/usr/share/gocode/src/github.com/vishvananda/netns/netns.go is in golang-github-vishvananda-netns-dev 0.0~git20150710.0.604eaf1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 | // Package netns allows ultra-simple network namespace handling. NsHandles
// can be retrieved and set. Note that the current namespace is thread
// local so actions that set and reset namespaces should use LockOSThread
// to make sure the namespace doesn't change due to a goroutine switch.
// It is best to close NsHandles when you are done with them. This can be
// accomplished via a `defer ns.Close()` on the handle. Changing namespaces
// requires elevated privileges, so in most cases this code needs to be run
// as root.
package netns
import (
"fmt"
"syscall"
)
// NsHandle is a handle to a network namespace. It can be cast directly
// to an int and used as a file descriptor.
type NsHandle int
// Equal determines if two network handles refer to the same network
// namespace. This is done by comparing the device and inode that the
// file descripors point to.
func (ns NsHandle) Equal(other NsHandle) bool {
if ns == other {
return true
}
var s1, s2 syscall.Stat_t
if err := syscall.Fstat(int(ns), &s1); err != nil {
return false
}
if err := syscall.Fstat(int(other), &s2); err != nil {
return false
}
return (s1.Dev == s2.Dev) && (s1.Ino == s2.Ino)
}
// String shows the file descriptor number and its dev and inode.
func (ns NsHandle) String() string {
var s syscall.Stat_t
if ns == -1 {
return "NS(None)"
}
if err := syscall.Fstat(int(ns), &s); err != nil {
return fmt.Sprintf("NS(%d: unknown)", ns)
}
return fmt.Sprintf("NS(%d: %d, %d)", ns, s.Dev, s.Ino)
}
// IsOpen returns true if Close() has not been called.
func (ns NsHandle) IsOpen() bool {
return ns != -1
}
// Close closes the NsHandle and resets its file descriptor to -1.
// It is not safe to use an NsHandle after Close() is called.
func (ns *NsHandle) Close() error {
if err := syscall.Close(int(*ns)); err != nil {
return err
}
(*ns) = -1
return nil
}
// Get an empty (closed) NsHandle
func None() NsHandle {
return NsHandle(-1)
}
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