docker/pkg/libcontainer/nsinit/main.go

83 строки
1.6 KiB
Go

package main
import (
"encoding/json"
"errors"
"github.com/dotcloud/docker/pkg/libcontainer"
"io/ioutil"
"log"
"os"
"strconv"
)
var (
ErrUnsupported = errors.New("Unsupported method")
ErrWrongArguments = errors.New("Wrong argument count")
)
func main() {
container, err := loadContainer()
if err != nil {
log.Fatal(err)
}
argc := len(os.Args)
if argc < 2 {
log.Fatal(ErrWrongArguments)
}
switch os.Args[1] {
case "exec": // this is executed outside of the namespace in the cwd
var exitCode int
nspid, err := readPid()
if err != nil {
if !os.IsNotExist(err) {
log.Fatal(err)
}
}
if nspid > 0 {
exitCode, err = execinCommand(container, nspid, os.Args[2:])
} else {
exitCode, err = execCommand(container, os.Args[2:])
}
if err != nil {
log.Fatal(err)
}
os.Exit(exitCode)
case "init": // this is executed inside of the namespace to setup the container
if argc < 3 {
log.Fatal(ErrWrongArguments)
}
if err := initCommand(container, os.Args[2], os.Args[3:]); err != nil {
log.Fatal(err)
}
default:
log.Fatalf("command not supported for nsinit %s", os.Args[1])
}
}
func loadContainer() (*libcontainer.Container, error) {
f, err := os.Open("container.json")
if err != nil {
return nil, err
}
defer f.Close()
var container *libcontainer.Container
if err := json.NewDecoder(f).Decode(&container); err != nil {
return nil, err
}
return container, nil
}
func readPid() (int, error) {
data, err := ioutil.ReadFile(".nspid")
if err != nil {
return -1, err
}
pid, err := strconv.Atoi(string(data))
if err != nil {
return -1, err
}
return pid, nil
}