Fixed problem with variables containing \n.

The /.dockerenv file is now a marshalled json array so that environment
variables with \n and other weird values are supported.

container.go

@@ -444,16 +444,11 @@ func (container *Container) SaveHostConfig(hostConfig *HostConfig) (err error) {
 }
 
 func (container *Container) generateEnvConfig(env []string) error {
-	fo, err := os.Create(container.EnvConfigPath())
+	data, err := json.Marshal(env)
 	if err != nil {
 		return err
 	}
-	defer fo.Close()
-	for _, item := range env {
-		if _, err := fo.WriteString(item + "\n"); err != nil {
-			return err
-		}
-	}
+	ioutil.WriteFile(container.EnvConfigPath(), data, 0600)
 	return nil
 }
 

container_test.go

@@ -974,9 +974,10 @@ func TestTty(t *testing.T) {
 
 func TestEnv(t *testing.T) {
 	os.Setenv("TRUE", "false")
+	os.Setenv("TRICKY", "tri\ncky\n")
 	runtime := mkRuntime(t)
 	defer nuke(runtime)
-	config, _, _, err := ParseRun([]string{"-e=FALSE=true", "-e=TRUE", GetTestImage(runtime).ID, "env"}, nil)
+	config, _, _, err := ParseRun([]string{"-e=FALSE=true", "-e=TRUE", "-e=TRICKY", GetTestImage(runtime).ID, "env"}, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1012,6 +1013,9 @@ func TestEnv(t *testing.T) {
 		"HOSTNAME=" + container.ShortID(),
 		"FALSE=true",
 		"TRUE=false",
+		"TRICKY=tri",
+		"cky",
+		"",
 	}
 	sort.Strings(goodEnv)
 	if len(goodEnv) != len(actualEnv) {

sysinit/sysinit.go

@@ -1,6 +1,7 @@
 package sysinit
 
 import (
+	"encoding/json"
 	"flag"
 	"fmt"
 	"github.com/dotcloud/docker/netlink"
@@ -72,11 +73,15 @@ func changeUser(u string) {
 // Clear environment pollution introduced by lxc-start
 func cleanupEnv() {
 	os.Clearenv()
+	var lines []string
 	content, err := ioutil.ReadFile("/.dockerenv")
 	if err != nil {
 		log.Fatalf("Unable to load environment variables: %v", err)
 	}
-	lines := strings.Split(string(content), "\n")
+	err = json.Unmarshal(content, &lines)
+	if err != nil {
+		log.Fatalf("Unable to unmarshal environment variables: %v", err)
+	}
 	for _, kv := range lines {
 		parts := strings.SplitN(kv, "=", 2)
 		if len(parts) == 1 {