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package lxc
import (
"encoding/json"
"fmt"
"github.com/dotcloud/docker/pkg/netlink"
"github.com/dotcloud/docker/pkg/user"
"github.com/dotcloud/docker/runtime/execdriver"
"github.com/syndtr/gocapability/capability"
"io/ioutil"
"net"
"os"
"strings"
"syscall"
)
// Clear environment pollution introduced by lxc-start
func setupEnv(args *execdriver.InitArgs) error {
// Get env
var env []string
content, err := ioutil.ReadFile(".dockerenv")
if err != nil {
return fmt.Errorf("Unable to load environment variables: %v", err)
}
if err := json.Unmarshal(content, &env); err != nil {
return fmt.Errorf("Unable to unmarshal environment variables: %v", err)
}
// Propagate the plugin-specific container env variable
env = append(env, "container="+os.Getenv("container"))
args.Env = env
os.Clearenv()
for _, kv := range args.Env {
parts := strings.SplitN(kv, "=", 2)
if len(parts) == 1 {
parts = append(parts, "")
}
os.Setenv(parts[0], parts[1])
}
return nil
}
func setupHostname(args *execdriver.InitArgs) error {
hostname := getEnv(args, "HOSTNAME")
if hostname == "" {
return nil
}
return setHostname(hostname)
}
// Setup networking
func setupNetworking(args *execdriver.InitArgs) error {
if args.Ip != "" {
// eth0
iface, err := net.InterfaceByName("eth0")
if err != nil {
return fmt.Errorf("Unable to set up networking: %v", err)
}
ip, ipNet, err := net.ParseCIDR(args.Ip)
if err != nil {
return fmt.Errorf("Unable to set up networking: %v", err)
}
if err := netlink.NetworkLinkAddIp(iface, ip, ipNet); err != nil {
return fmt.Errorf("Unable to set up networking: %v", err)
}
if err := netlink.NetworkSetMTU(iface, args.Mtu); err != nil {
return fmt.Errorf("Unable to set MTU: %v", err)
}
if err := netlink.NetworkLinkUp(iface); err != nil {
return fmt.Errorf("Unable to set up networking: %v", err)
}
// loopback
iface, err = net.InterfaceByName("lo")
if err != nil {
return fmt.Errorf("Unable to set up networking: %v", err)
}
if err := netlink.NetworkLinkUp(iface); err != nil {
return fmt.Errorf("Unable to set up networking: %v", err)
}
}
if args.Gateway != "" {
gw := net.ParseIP(args.Gateway)
if gw == nil {
return fmt.Errorf("Unable to set up networking, %s is not a valid gateway IP", args.Gateway)
}
if err := netlink.AddDefaultGw(gw); err != nil {
return fmt.Errorf("Unable to set up networking: %v", err)
}
}
return nil
}
// Setup working directory
func setupWorkingDirectory(args *execdriver.InitArgs) error {
if args.WorkDir == "" {
return nil
}
if err := syscall.Chdir(args.WorkDir); err != nil {
return fmt.Errorf("Unable to change dir to %v: %v", args.WorkDir, err)
}
return nil
}
// Takes care of dropping privileges to the desired user
func changeUser(args *execdriver.InitArgs) error {
uid, gid, suppGids, err := user.GetUserGroupSupplementary(
args.User,
syscall.Getuid(), syscall.Getgid(),
)
if err != nil {
return err
}
if err := syscall.Setgroups(suppGids); err != nil {
return fmt.Errorf("Setgroups failed: %v", err)
}
if err := syscall.Setgid(gid); err != nil {
return fmt.Errorf("Setgid failed: %v", err)
}
if err := syscall.Setuid(uid); err != nil {
return fmt.Errorf("Setuid failed: %v", err)
}
return nil
}
func setupCapabilities(args *execdriver.InitArgs) error {
if args.Privileged {
return nil
}
drop := []capability.Cap{
capability.CAP_SETPCAP,
capability.CAP_SYS_MODULE,
capability.CAP_SYS_RAWIO,
capability.CAP_SYS_PACCT,
capability.CAP_SYS_ADMIN,
capability.CAP_SYS_NICE,
capability.CAP_SYS_RESOURCE,
capability.CAP_SYS_TIME,
capability.CAP_SYS_TTY_CONFIG,
capability.CAP_AUDIT_WRITE,
capability.CAP_AUDIT_CONTROL,
capability.CAP_MAC_OVERRIDE,
capability.CAP_MAC_ADMIN,
capability.CAP_NET_ADMIN,
}
c, err := capability.NewPid(os.Getpid())
if err != nil {
return err
}
c.Unset(capability.CAPS|capability.BOUNDS, drop...)
if err := c.Apply(capability.CAPS | capability.BOUNDS); err != nil {
return err
}
return nil
}
func getEnv(args *execdriver.InitArgs, key string) string {
for _, kv := range args.Env {
parts := strings.SplitN(kv, "=", 2)
if parts[0] == key && len(parts) == 2 {
return parts[1]
}
}
return ""
}
|
