+ auto-update: copy supporting files (README, etc.)

AGHTechDoc.md

@@ -217,10 +217,13 @@ Algorithm of an update by command:
 	* Copy the current configuration file to the directory we unpacked new AGH to
 	* Check configuration compatibility by executing `./AGH --check-config`.  If this command fails, we won't be able to update.
 	* Create `backup-vXXX` directory and copy the current configuration file there
-	* Stop all tasks, including DNS server, DHCP server, HTTP server
+	* Copy supporting files (README, LICENSE, etc.) to backup directory
+	* Copy supporting files from the update directory to the current directory
 	* Move the current binary file to backup directory
 	* Note: if power fails here, AGH won't be able to start at system boot.  Administrator has to fix it manually
 	* Move new binary file to the current directory
+	* Send response to UI
+	* Stop all tasks, including DNS server, DHCP server, HTTP server
 	* If AGH is running as a service, use service control functionality to restart
 	* If AGH is not running as a service, use the current process arguments to start a new process
 	* Exit process

control_update.go

@@ -305,11 +305,35 @@ func targzFileUnpack(tarfile, outdir string) ([]string, error) {
 	return files, err2
 }
 
-// Perform an update procedure
-func doUpdate(u *updateInfo) error {
-	log.Info("Updating from %s to %s.  URL:%s  Package:%s",
-		VersionString, u.newVer, u.pkgURL, u.pkgName)
+func copySupportingFiles(files []string, srcdir, dstdir string, useSrcNameOnly, useDstNameOnly bool) error {
+	for _, f := range files {
+		_, name := filepath.Split(f)
+		if name == "AdGuardHome" || name == "AdGuardHome.exe" || name == "AdGuardHome.yaml" {
+			continue
+		}
 
+		src := filepath.Join(srcdir, f)
+		if useSrcNameOnly {
+			src = filepath.Join(srcdir, name)
+		}
+
+		dst := filepath.Join(dstdir, f)
+		if useDstNameOnly {
+			dst = filepath.Join(dstdir, name)
+		}
+
+		err := copyFile(src, dst)
+		if err != nil && !os.IsNotExist(err) {
+			return err
+		}
+
+		log.Tracef("Copied: %s -> %s", src, dst)
+	}
+	return nil
+}
+
+// Download package file and save it to disk
+func getPackageFile(u *updateInfo) error {
 	resp, err := client.Get(u.pkgURL)
 	if err != nil {
 		return fmt.Errorf("HTTP request failed: %s", err)
@@ -329,19 +353,33 @@ func doUpdate(u *updateInfo) error {
 	if err != nil {
 		return fmt.Errorf("ioutil.WriteFile() failed: %s", err)
 	}
+	return nil
+}
+
+// Perform an update procedure
+func doUpdate(u *updateInfo) error {
+	log.Info("Updating from %s to %s.  URL:%s  Package:%s",
+		VersionString, u.newVer, u.pkgURL, u.pkgName)
+
+	var err error
+	err = getPackageFile(u)
+	if err != nil {
+		return err
+	}
 
 	log.Tracef("Unpacking the package")
 	_ = os.Mkdir(u.updateDir, 0755)
 	_, file := filepath.Split(u.pkgName)
+	var files []string
 	if strings.HasSuffix(file, ".zip") {
-		_, err = zipFileUnpack(u.pkgName, u.updateDir)
+		files, err = zipFileUnpack(u.pkgName, u.updateDir)
 		if err != nil {
 			return fmt.Errorf("zipFileUnpack() failed: %s", err)
 		}
 	} else if strings.HasSuffix(file, ".tar.gz") {
-		_, err = targzFileUnpack(u.pkgName, u.updateDir)
+		files, err = targzFileUnpack(u.pkgName, u.updateDir)
 		if err != nil {
-			return fmt.Errorf("zipFileUnpack() failed: %s", err)
+			return fmt.Errorf("targzFileUnpack() failed: %s", err)
 		}
 	} else {
 		return fmt.Errorf("Unknown package extension")
@@ -365,6 +403,20 @@ func doUpdate(u *updateInfo) error {
 		return fmt.Errorf("copyFile() failed: %s", err)
 	}
 
+	// ./README.md -> backup/README.md
+	err = copySupportingFiles(files, config.ourWorkingDir, u.backupDir, true, true)
+	if err != nil {
+		return fmt.Errorf("copySupportingFiles(%s, %s) failed: %s",
+			config.ourWorkingDir, u.backupDir, err)
+	}
+
+	// update/[AdGuardHome/]README.md -> ./README.md
+	err = copySupportingFiles(files, u.updateDir, config.ourWorkingDir, false, true)
+	if err != nil {
+		return fmt.Errorf("copySupportingFiles(%s, %s) failed: %s",
+			u.updateDir, config.ourWorkingDir, err)
+	}
+
 	log.Tracef("Renaming: %s -> %s", u.curBinName, u.bkpBinName)
 	err = os.Rename(u.curBinName, u.bkpBinName)
 	if err != nil {

control_update_test.go

@@ -7,6 +7,7 @@ import (
 
 func testDoUpdate(t *testing.T) {
 	config.DNS.Port = 0
+	config.ourWorkingDir = "."
 	u := updateInfo{
 		pkgURL:           "https://github.com/AdguardTeam/AdGuardHome/releases/download/v0.95/AdGuardHome_v0.95_linux_amd64.tar.gz",
 		pkgName:          "./AdGuardHome_v0.95_linux_amd64.tar.gz",