From 905f2d08c55189575a1b8b04c2e2ead7d7a0602f Mon Sep 17 00:00:00 2001
From: Cuong Manh Le <cuong@windscribe.com>
Date: Thu, 25 Jul 2024 22:23:01 +0700
Subject: [PATCH] cmd/cli: fix reset DNS when doing self-uninstall

While at it, also using "ctrld uninstall" on unix platform, ensuring
everything is cleanup properly.
---
 cmd/cli/cli.go              | 20 ++++---------
 cmd/cli/dns_proxy.go        |  5 ++--
 cmd/cli/self_kill_others.go | 16 +++++++++++
 cmd/cli/self_kill_unix.go   | 56 +++++++++++++++++++++++++++++++++++++
 4 files changed, 79 insertions(+), 18 deletions(-)
 create mode 100644 cmd/cli/self_kill_others.go
 create mode 100644 cmd/cli/self_kill_unix.go

diff --git a/cmd/cli/cli.go b/cmd/cli/cli.go
index 42e20b6..9ed3602 100644
--- a/cmd/cli/cli.go
+++ b/cmd/cli/cli.go
@@ -1157,7 +1157,7 @@ func run(appCallback *AppCallback, stopCh chan struct{}) {
 			}
 
 			cdLogger := mainLog.Load().With().Str("mode", "cd").Logger()
-			_ = uninstallIfInvalidCdUID(err, cdLogger)
+			_ = uninstallIfInvalidCdUID(err, p, cdLogger)
 			cdLogger.Fatal().Err(err).Msg("failed to fetch resolver config")
 		}
 	}
@@ -2617,26 +2617,16 @@ func doValidateCdRemoteConfig(cdUID string) {
 }
 
 // uninstallIfInvalidCdUID performs self-uninstallation if the ControlD device does not exist.
-func uninstallIfInvalidCdUID(err error, logger zerolog.Logger) bool {
+func uninstallIfInvalidCdUID(err error, p *prog, logger zerolog.Logger) bool {
 	var uer *controld.UtilityErrorResponse
 	if errors.As(err, &uer) && uer.ErrorField.Code == controld.InvalidConfigCode {
-		s, err := newService(&prog{}, svcConfig)
+		s, err := newService(p, svcConfig)
 		if err != nil {
 			logger.Warn().Err(err).Msg("failed to create new service")
 			return false
 		}
-		if netIface, _ := netInterface(iface); netIface != nil {
-			if err := restoreNetworkManager(); err != nil {
-				logger.Error().Err(err).Msg("could not restore NetworkManager")
-				return false
-			}
-			logger.Debug().Str("iface", netIface.Name).Msg("Restoring DNS for interface")
-			if err := resetDNS(netIface); err != nil {
-				logger.Warn().Err(err).Msg("something went wrong while restoring DNS")
-			} else {
-				logger.Debug().Str("iface", netIface.Name).Msg("Restoring DNS successfully")
-			}
-		}
+
+		p.resetDNS()
 
 		tasks := []task{{s.Uninstall, true}}
 		if doTasks(tasks) {
diff --git a/cmd/cli/dns_proxy.go b/cmd/cli/dns_proxy.go
index 6e8c1fa..9519468 100644
--- a/cmd/cli/dns_proxy.go
+++ b/cmd/cli/dns_proxy.go
@@ -862,9 +862,8 @@ func (p *prog) doSelfUninstall(answer *dns.Msg) {
 		p.checkingSelfUninstall = true
 		_, err := controld.FetchResolverConfig(cdUID, rootCmd.Version, cdDev)
 		logger.Debug().Msg("maximum number of refused queries reached, checking device status")
-		if uninstallIfInvalidCdUID(err, logger) {
-			logger.Fatal().Msgf("service was uninstalled because device %q does not exist", cdUID)
-		}
+		selfUninstall(err, p, logger)
+
 		if err != nil {
 			logger.Warn().Err(err).Msg("could not fetch resolver config")
 		}
diff --git a/cmd/cli/self_kill_others.go b/cmd/cli/self_kill_others.go
new file mode 100644
index 0000000..1fe9b8a
--- /dev/null
+++ b/cmd/cli/self_kill_others.go
@@ -0,0 +1,16 @@
+//go:build !unix
+
+package cli
+
+import (
+	"os"
+
+	"github.com/rs/zerolog"
+)
+
+func selfUninstall(err error, p *prog, logger zerolog.Logger) {
+	if uninstallIfInvalidCdUID(err, p, logger) {
+		logger.Warn().Msgf("service was uninstalled because device %q does not exist", cdUID)
+		os.Exit(0)
+	}
+}
diff --git a/cmd/cli/self_kill_unix.go b/cmd/cli/self_kill_unix.go
new file mode 100644
index 0000000..95767fe
--- /dev/null
+++ b/cmd/cli/self_kill_unix.go
@@ -0,0 +1,56 @@
+//go:build unix
+
+package cli
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"runtime"
+	"syscall"
+
+	"github.com/Control-D-Inc/ctrld/internal/controld"
+	"github.com/rs/zerolog"
+)
+
+func selfUninstall(err error, p *prog, logger zerolog.Logger) {
+	var uer *controld.UtilityErrorResponse
+	if errors.As(err, &uer) && uer.ErrorField.Code == controld.InvalidConfigCode {
+		if runtime.GOOS == "linux" {
+			s, err := newService(p, svcConfig)
+			if err != nil {
+				logger.Warn().Err(err).Msg("failed to create new service")
+			} else {
+				selfUninstallLinux(err, p, logger)
+				_ = s.Stop()
+				os.Exit(0)
+			}
+		}
+
+		bin, err := os.Executable()
+		if err != nil {
+			logger.Fatal().Err(err).Msg("could not determine executable")
+		}
+		args := []string{"uninstall"}
+		if !deactivationPinNotSet() {
+			args = append(args, fmt.Sprintf("--pin=%d", cdDeactivationPin))
+		}
+		cmd := exec.Command(bin, args...)
+		cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+		if err := cmd.Start(); err != nil {
+			logger.Fatal().Err(err).Msg("could not start self uninstall command")
+		}
+		cmd.Stdout = os.Stdout
+		cmd.Stderr = os.Stderr
+		logger.Warn().Msgf("service was uninstalled because device %q does not exist", cdUID)
+		_ = cmd.Wait()
+		os.Exit(0)
+	}
+}
+
+func selfUninstallLinux(err error, p *prog, logger zerolog.Logger) {
+	if uninstallIfInvalidCdUID(err, p, logger) {
+		logger.Warn().Msgf("service was uninstalled because device %q does not exist", cdUID)
+	}
+}