Revert "common/daemon: add a method to reexec itself"

This reverts commit 216786d40e. We don't
really need that if we move logic to cmd package.

cmd/components.go

@@ -39,7 +39,6 @@ func StartStopComponents(r *reporter.Reporter, daemonComponent daemon.Component,
 
 	<-daemonComponent.Terminated()
 	r.Info().Msg("stopping all components")
-	daemonComponent.FinishReexec()
 	return nil
 }
 

common/daemon/root.go

@@ -9,7 +9,6 @@ package daemon
 import (
 	"os"
 	"os/signal"
-	"sync/atomic"
 	"syscall"
 
 	"gopkg.in/tomb.v2"
@@ -21,8 +20,6 @@ import (
 type Component interface {
 	Start() error
 	Stop() error
-	Reexec()
-	FinishReexec()
 	Track(t *tomb.Tomb, who string)
 
 	// Lifecycle
@@ -35,7 +32,6 @@ type Component interface {
 type realComponent struct {
 	r     *reporter.Reporter
 	tombs []tombWithOrigin
-	shouldReexec atomic.Bool
 
 	lifecycleComponent
 }
@@ -74,12 +70,11 @@ func (c *realComponent) Start() error {
 			c.Terminate()
 		}(t)
 	}
-	// On signal, terminate or reexec
+	// On signal, terminate
 	go func() {
 		signals := make(chan os.Signal, 1)
 		signal.Notify(signals,
-			syscall.SIGINT,
-			syscall.SIGTERM)
+			syscall.SIGINT, syscall.SIGTERM)
 		select {
 		case s := <-signals:
 			c.r.Debug().Stringer("signal", s).Msg("signal received")
@@ -102,30 +97,6 @@ func (c *realComponent) Stop() error {
 	return nil
 }
 
-// Reexec will reexecute the current process with the same arguments.
-func (c *realComponent) Reexec() {
-	c.shouldReexec.Store(true)
-	c.Terminate()
-}
-
-// FinishReexec should be called just before exiting to trigger the real reexec.
-func (c *realComponent) FinishReexec() {
-	if c.shouldReexec.Load() {
-		executable, err := os.Executable()
-		if err != nil {
-			c.r.Err(err).Msg("cannot get executable name")
-			return
-		}
-
-		env := os.Environ()
-		args := append([]string{executable}, os.Args[1:]...)
-		c.r.Info().Strs("args", args).Msg("reexec in progress")
-		if err := syscall.Exec(executable, args, env); err != nil {
-			c.r.Err(err).Msg("cannot reexec")
-		}
-	}
-}
-
 // Add a new tomb to be tracked. This is only used before Start().
 func (c *realComponent) Track(t *tomb.Tomb, who string) {
 	c.tombs = append(c.tombs, tombWithOrigin{

common/daemon/root_test.go

@@ -5,7 +5,6 @@ package daemon
 
 import (
 	"errors"
-	"os"
 	"syscall"
 	"testing"
 	"testing/synctest"
@@ -63,28 +62,6 @@ func TestTerminateWithSignal(t *testing.T) {
 	}
 }
 
-func TestReexecWithSignal(t *testing.T) {
-
-	r := reporter.NewMock(t)
-	c, err := New(r)
-	if err != nil {
-		t.Fatalf("New() error:\n%+v", err)
-	}
-	helpers.StartStop(t, c)
-
-	c.Reexec()
-	if os.Getenv("TEST_DAEMON_REEXEC") == "1" {
-		// This is a way to increase a bit coverage
-		executable, _ := os.Executable()
-		os.Remove(executable)
-		c.FinishReexec()
-		return
-	}
-	os.Setenv("TEST_DAEMON_REEXEC", "1")
-	c.FinishReexec()
-	t.Fatalf("No reexec done!")
-}
-
 func TestStop(t *testing.T) {
 	r := reporter.NewMock(t)
 	c, err := New(r)

common/daemon/tests.go

@@ -17,8 +17,6 @@ type MockComponent struct {
 	lifecycleComponent
 }
 
-var _ Component = &MockComponent{}
-
 // NewMock will create a daemon component that does nothing.
 func NewMock(t testing.TB) Component {
 	t.Helper()
@@ -40,14 +38,6 @@ func (c *MockComponent) Stop() error {
 	return nil
 }
 
-// Reexec does nothing for the mock implementation
-func (c *MockComponent) Reexec() {
-}
-
-// FinishReexec does nothing for the mock implementation
-func (c *MockComponent) FinishReexec() {
-}
-
 // Track does nothing
 func (c *MockComponent) Track(_ *tomb.Tomb, _ string) {
 }