Move .dockerenv parsing to lxc driver

This is not needed for e.g. the native driver

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)

execdriver/lxc/driver.go

@@ -21,6 +21,10 @@ const DriverName = "lxc"
 
 func init() {
 	execdriver.RegisterInitFunc(DriverName, func(args *execdriver.InitArgs) error {
+		if err := setupEnv(args); err != nil {
+			return err
+		}
+
 		if err := setupHostname(args); err != nil {
 			return err
 		}

execdriver/lxc/init.go

@@ -1,17 +1,47 @@
 package lxc
 
 import (
+	"encoding/json"
 	"fmt"
 	"github.com/dotcloud/docker/execdriver"
 	"github.com/dotcloud/docker/pkg/netlink"
 	"github.com/dotcloud/docker/pkg/user"
 	"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 == "" {

sysinit/sysinit.go

@@ -1,33 +1,16 @@
 package sysinit
 
 import (
-	"encoding/json"
 	"flag"
 	"fmt"
 	"github.com/dotcloud/docker/execdriver"
 	_ "github.com/dotcloud/docker/execdriver/lxc"
 	_ "github.com/dotcloud/docker/execdriver/native"
-	"io/ioutil"
 	"log"
 	"os"
-	"strings"
 )
 
-// Clear environment pollution introduced by lxc-start
-func setupEnv(args *execdriver.InitArgs) {
-	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])
-	}
-}
-
 func executeProgram(args *execdriver.InitArgs) error {
-	setupEnv(args)
-
 	dockerInitFct, err := execdriver.GetInitFunc(args.Driver)
 	if err != nil {
 		panic(err)
@@ -59,25 +42,12 @@ func SysInit() {
 	)
 	flag.Parse()
 
-	// Get env
-	var env []string
-	content, err := ioutil.ReadFile(".dockerenv")
-	if err != nil {
-		log.Fatalf("Unable to load environment variables: %v", err)
-	}
-	if err := json.Unmarshal(content, &env); err != nil {
-		log.Fatalf("Unable to unmarshal environment variables: %v", err)
-	}
-	// Propagate the plugin-specific container env variable
-	env = append(env, "container="+os.Getenv("container"))
-
 	args := &execdriver.InitArgs{
 		User:       *user,
 		Gateway:    *gateway,
 		Ip:         *ip,
 		WorkDir:    *workDir,
 		Privileged: *privileged,
-		Env:        env,
 		Args:       flag.Args(),
 		Mtu:        *mtu,
 		Driver:     *driver,