Pull request: 4677 openwrt service

Merge in DNS/adguard-home from 4677-openwrt-service to master

Updates #4677.

Squashed commit of the following:

commit 6aed4036d3338a601a7ec5ef1ca74a407ae4c0e2
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Jun 20 14:49:33 2022 +0300

    home: imp docs

commit 54e32fa47ed11e50c6405ced90a400e4e69f021d
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Jun 20 14:30:08 2022 +0300

    home: fix wrt svc

CHANGELOG.md

@@ -30,8 +30,13 @@ and this project adheres to
 
 - Go 1.17 support.  v0.109.0 will require at least Go 1.18 to build.
 
+### Fixed
+
+- Broken service installation on OpenWrt ([#4677]).
+
 [#2993]: https://github.com/AdguardTeam/AdGuardHome/issues/2993
 [#3057]: https://github.com/AdguardTeam/AdGuardHome/issues/3057
+[#4677]: https://github.com/AdguardTeam/AdGuardHome/issues/4677
 
 [ddr-draft-06]:   https://www.ietf.org/archive/id/draft-ietf-add-ddr-06.html
 

internal/home/service_linux.go

@@ -9,7 +9,14 @@ import (
 )
 
 func chooseSystem() {
-	if sys := service.ChosenSystem(); sys.String() == "unix-systemv" {
+	sys := service.ChosenSystem()
+	// By default, package service uses the SysV system if it cannot detect
+	// anything other, but the update-rc.d fix should not be applied on OpenWrt,
+	// so exclude it explicitly.
+	//
+	// See https://github.com/AdguardTeam/AdGuardHome/issues/4480 and
+	// https://github.com/AdguardTeam/AdGuardHome/issues/4677.
+	if sys.String() == "unix-systemv" && !aghos.IsOpenWrt() {
 		service.ChooseSystem(sysvSystem{System: sys})
 	}
 }