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143 lines
3 KiB
Go
143 lines
3 KiB
Go
package lxc
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import (
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"encoding/json"
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"flag"
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"fmt"
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"io/ioutil"
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"log"
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"os"
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"os/exec"
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"runtime"
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"strings"
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"syscall"
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"github.com/docker/docker/pkg/reexec"
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)
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// Args provided to the init function for a driver
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type InitArgs struct {
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User string
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Gateway string
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Ip string
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WorkDir string
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Privileged bool
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Env []string
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Args []string
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Mtu int
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Console string
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Pipe int
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Root string
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CapAdd string
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CapDrop string
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}
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func init() {
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// like always lxc requires a hack to get this to work
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reexec.Register("/.dockerinit", dockerInititalizer)
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}
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func dockerInititalizer() {
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initializer()
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}
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// initializer is the lxc driver's init function that is run inside the namespace to setup
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// additional configurations
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func initializer() {
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runtime.LockOSThread()
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args := getArgs()
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if err := setupNamespace(args); err != nil {
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log.Fatal(err)
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}
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}
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func setupNamespace(args *InitArgs) error {
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if err := setupEnv(args); err != nil {
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return err
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}
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if err := finalizeNamespace(args); err != nil {
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return err
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}
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path, err := exec.LookPath(args.Args[0])
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if err != nil {
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log.Printf("Unable to locate %v", args.Args[0])
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os.Exit(127)
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}
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if err := syscall.Exec(path, args.Args, os.Environ()); err != nil {
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return fmt.Errorf("dockerinit unable to execute %s - %s", path, err)
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}
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return nil
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}
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func getArgs() *InitArgs {
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var (
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// Get cmdline arguments
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user = flag.String("u", "", "username or uid")
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gateway = flag.String("g", "", "gateway address")
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ip = flag.String("i", "", "ip address")
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workDir = flag.String("w", "", "workdir")
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privileged = flag.Bool("privileged", false, "privileged mode")
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mtu = flag.Int("mtu", 1500, "interface mtu")
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capAdd = flag.String("cap-add", "", "capabilities to add")
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capDrop = flag.String("cap-drop", "", "capabilities to drop")
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)
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flag.Parse()
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return &InitArgs{
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User: *user,
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Gateway: *gateway,
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Ip: *ip,
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WorkDir: *workDir,
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Privileged: *privileged,
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Args: flag.Args(),
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Mtu: *mtu,
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CapAdd: *capAdd,
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CapDrop: *capDrop,
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}
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}
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// Clear environment pollution introduced by lxc-start
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func setupEnv(args *InitArgs) error {
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// Get env
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var env []string
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content, err := ioutil.ReadFile(".dockerenv")
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if err != nil {
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return fmt.Errorf("Unable to load environment variables: %v", err)
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}
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if err := json.Unmarshal(content, &env); err != nil {
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return fmt.Errorf("Unable to unmarshal environment variables: %v", err)
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}
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// Propagate the plugin-specific container env variable
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env = append(env, "container="+os.Getenv("container"))
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args.Env = env
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os.Clearenv()
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for _, kv := range args.Env {
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parts := strings.SplitN(kv, "=", 2)
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if len(parts) == 1 {
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parts = append(parts, "")
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}
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os.Setenv(parts[0], parts[1])
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}
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return nil
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}
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// Setup working directory
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func setupWorkingDirectory(args *InitArgs) error {
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if args.WorkDir == "" {
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return nil
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}
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if err := syscall.Chdir(args.WorkDir); err != nil {
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return fmt.Errorf("Unable to change dir to %v: %v", args.WorkDir, err)
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}
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return nil
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}
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