Set default home value (#281)

* Set default home value

* Apply  default home value based on user for run commands

* rename default home function

pkg/commands/run.go

@@ -17,12 +17,14 @@ limitations under the License.
 package commands
 
 import (
+	"fmt"
 	"os"
 	"os/exec"
 	"strconv"
 	"strings"
 	"syscall"
 
+	"github.com/GoogleContainerTools/kaniko/pkg/constants"
 	"github.com/GoogleContainerTools/kaniko/pkg/dockerfile"
 	"github.com/GoogleContainerTools/kaniko/pkg/util"
 	"github.com/google/go-containerregistry/pkg/v1"
@@ -59,7 +61,7 @@ func (r *RunCommand) ExecuteCommand(config *v1.Config, buildArgs *dockerfile.Bui
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
 	replacementEnvs := buildArgs.ReplacementEnvs(config.Env)
-	cmd.Env = replacementEnvs
+	cmd.Env = addDefaultHOME(config.User, replacementEnvs)
 	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
 
 	// If specified, run the command as a specific user
@@ -113,6 +115,22 @@ func (r *RunCommand) ExecuteCommand(config *v1.Config, buildArgs *dockerfile.Bui
 	return nil
 }
 
+// addDefaultHOME adds the default value for HOME if it isn't already set
+func addDefaultHOME(user string, envs []string) []string {
+	for _, env := range envs {
+		split := strings.SplitN(env, "=", 2)
+		if split[0] == constants.HOME {
+			return envs
+		}
+	}
+	// If user isn't set, set default value of HOME
+	if user == "" {
+		return append(envs, fmt.Sprintf("%s=%s", constants.HOME, constants.DefaultHOMEValue))
+	}
+	// If user is set, set value of HOME to /home/${user}
+	return append(envs, fmt.Sprintf("%s=/home/%s", constants.HOME, user))
+}
+
 // FilesToSnapshot returns nil for this command because we don't know which files
 // have changed, so we snapshot the entire system.
 func (r *RunCommand) FilesToSnapshot() []string {