/
namespace.go
149 lines (132 loc) · 2.94 KB
/
namespace.go
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package namespace
import (
"fmt"
"io/ioutil"
"log"
"os"
"path"
"runtime"
"strconv"
"syscall"
"golang.org/x/sys/unix"
)
const (
PROC_PATH = "/proc"
)
type Process struct {
PID int
}
type NameSpace struct {
Process *Process
Ino uint64
Dir string
OpenFd int
}
func (n *NameSpace) String() string {
return fmt.Sprintf("PID: %d Ino %d", n.Process.PID, n.Ino)
}
func (p *Process) String() string {
return fmt.Sprintf("PID: %d", p.PID)
}
func SetNetNs(fd int) error {
return unix.Setns(fd, syscall.CLONE_NEWNET)
}
func GetCurrentNetNSHandler() (int, error) {
path := fmt.Sprintf("/proc/%d/task/%d/ns/net", os.Getpid(), unix.Gettid())
return unix.Open(path, unix.O_RDONLY|unix.O_CLOEXEC, 0)
}
func DeleteCurrentNetNSHandler(fd int) {
unix.Close(fd)
}
func (ns *NameSpace) GetNetNSHandler() (int, error) {
var err error
ns.OpenFd, err = unix.Open(ns.Dir, unix.O_RDONLY|unix.O_CLOEXEC, 0)
return ns.OpenFd, err
}
func (ns *NameSpace) DeleteNetNSHandler() {
unix.Close(ns.OpenFd)
}
func ReadAllNetNameSpaces() ([]NameSpace, error) {
var ret []NameSpace
allProcesses, err := ReadAllProcesses()
if err != nil {
return nil, err
}
dupId := make(map[uint64]bool, 1)
for idx, process := range allProcesses {
netNs := path.Join("/", "proc", strconv.Itoa(process.PID), "ns", "net")
if dirFile, err := os.Open(netNs); err != nil {
//process may stoped
continue
} else {
defer dirFile.Close()
var stat syscall.Stat_t
if err = syscall.Fstat(int(dirFile.Fd()), &stat); err != nil {
return nil, err
}
if _, ok := dupId[stat.Ino]; ok {
continue
}
dupId[stat.Ino] = true
ret = append(ret, NameSpace{
Process: &allProcesses[idx],
Ino: stat.Ino,
Dir: netNs,
})
}
}
return ret, nil
}
func ReadAllProcesses() ([]Process, error) {
var ret []Process
dirs, err := ioutil.ReadDir(PROC_PATH)
if err != nil {
return nil, err
}
for _, info := range dirs {
if !info.IsDir() {
continue
} else {
if num, err := strconv.Atoi(info.Name()); err != nil {
continue
} else {
ret = append(ret, Process{
PID: num,
})
}
}
}
return ret, nil
}
func ForEachNetNS(ctx interface{}, fn func(interface{}) error) {
allNs, err := ReadAllNetNameSpaces()
if err != nil {
panic(err)
}
oriNetNS, err := GetCurrentNetNSHandler()
if err != nil {
panic(err)
}
//make sure calling goroutine allways run on same os trhead
runtime.LockOSThread()
defer runtime.UnlockOSThread()
for _, ns := range allNs {
if newNs, err := ns.GetNetNSHandler(); err != nil {
log.Println("can not open", ns.Dir)
} else {
if err := SetNetNs(newNs); err == nil {
if err := fn(ctx); err != nil {
ns.DeleteNetNSHandler()
break
}
} else {
log.Println("can not call setns ", ns.Dir, newNs, err)
}
}
ns.DeleteNetNSHandler()
}
if err := SetNetNs(oriNetNS); err != nil {
panic(fmt.Errorf("fail to recover to original ns %v", err))
}
DeleteCurrentNetNSHandler(oriNetNS)
}