[WIP] Simplify update system

service/updates/upgrade.go

@@ -0,0 +1,196 @@
+package updates
+
+import (
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"slices"
+	"strings"
+
+	"github.com/safing/portmaster/base/log"
+)
+
+const (
+	defaultFileMode      = os.FileMode(0o0644)
+	executableFileMode   = os.FileMode(0o0744)
+	executableUIFileMode = os.FileMode(0o0755)
+	defaultDirMode       = os.FileMode(0o0755)
+)
+
+func (u *Updater) upgrade(downloader *Downloader, ignoreVersion bool) error {
+	// Lock index for the upgrade.
+	u.indexLock.Lock()
+	defer u.indexLock.Unlock()
+
+	// Check if we should upgrade at all.
+	if !ignoreVersion {
+		if err := u.index.ShouldUpgradeTo(downloader.index); err != nil {
+			return fmt.Errorf("cannot upgrade: %w", ErrNoUpdateAvailable)
+		}
+	}
+
+	// Execute the upgrade.
+	upgradeError := u.upgradeMoveFiles(downloader, ignoreVersion)
+	if upgradeError == nil {
+		return nil
+	}
+
+	// Attempt to recover from failed upgrade.
+	recoveryErr := u.recoverFromFailedUpgrade()
+	if recoveryErr == nil {
+		return fmt.Errorf("upgrade failed, but recovery was successful: %w", upgradeError)
+	}
+
+	// Recovery failed too.
+	return fmt.Errorf("upgrade (including recovery) failed: %s", upgradeError)
+}
+
+func (u *Updater) upgradeMoveFiles(downloader *Downloader, ignoreVersion bool) error {
+	// Important:
+	// We assume that the downloader has done its job and all artifacts are verified.
+	// Files will just be moved here.
+	// In case the files are copied, they are verified in the process.
+
+	// Reset purge directory, so that we can do a clean rollback later.
+	_ = os.RemoveAll(u.cfg.PurgeDirectory)
+	err := os.MkdirAll(u.cfg.PurgeDirectory, defaultDirMode)
+	if err != nil {
+		return fmt.Errorf("failed to create purge directory: %w", err)
+	}
+
+	// Move current version files into purge folder.
+	log.Debugf("updates: removing the old version (v%s from %s)", u.index.Version, u.index.Published)
+	files, err := os.ReadDir(u.cfg.Directory)
+	if err != nil {
+		return fmt.Errorf("read current directory: %w", err)
+	}
+	for _, file := range files {
+		// Check if file is ignored.
+		if slices.Contains(u.cfg.Ignore, file.Name()) {
+			continue
+		}
+
+		// Otherwise, move file to purge dir.
+		src := filepath.Join(u.cfg.Directory, file.Name())
+		dst := filepath.Join(u.cfg.PurgeDirectory, file.Name())
+		err := moveFile(src, dst, "", file.Type().Perm())
+		if err != nil {
+			return fmt.Errorf("failed to move current file %s to purge dir: %w", file.Name(), err)
+		}
+	}
+
+	// Move the new index file into main directory.
+	log.Debugf("updates: installing the new version (v%s from %s)", u.index.Version, u.index.Published)
+	src := filepath.Join(u.cfg.DownloadDirectory, u.cfg.IndexFile)
+	dst := filepath.Join(u.cfg.Directory, u.cfg.IndexFile)
+	err = moveFile(src, dst, "", defaultFileMode)
+	if err != nil {
+		return fmt.Errorf("failed to move index file to %s: %w", dst, err)
+	}
+
+	// Move downloaded files to the current version folder.
+	for _, artifact := range downloader.index.Artifacts {
+		src = filepath.Join(u.cfg.DownloadDirectory, artifact.Filename)
+		dst = filepath.Join(u.cfg.Directory, artifact.Filename)
+		err = moveFile(src, dst, artifact.SHA256, artifact.GetFileMode())
+		if err != nil {
+			return fmt.Errorf("failed to move file %s: %w", artifact.Filename, err)
+		} else {
+			log.Debugf("updates: %s moved", artifact.Filename)
+		}
+	}
+
+	// Set new index on module.
+	u.index = downloader.index
+	log.Infof("updates: update complete (v%s from %s)", u.index.Version, u.index.Published)
+
+	return nil
+}
+
+// moveFile moves a file and falls back to copying if it fails.
+func moveFile(currentPath, newPath string, sha256sum string, fileMode fs.FileMode) error {
+	// Try to simply move file.
+	err := os.Rename(currentPath, newPath)
+	if err == nil {
+		// Moving was successful, return.
+		return nil
+	}
+	log.Tracef("updates: failed to move to %q, falling back to copy+delete: %w", newPath, err)
+
+	// Copy and check the checksum while we are at it.
+	err = copyAndCheckSHA256Sum(currentPath, newPath, sha256sum, fileMode)
+	if err != nil {
+		return fmt.Errorf("move failed, copy+delete fallback failed: %w", err)
+	}
+
+	return nil
+}
+
+// recoverFromFailedUpgrade attempts to roll back any moved files by the upgrade process.
+func (u *Updater) recoverFromFailedUpgrade() error {
+	// Get list of files from purge dir.
+	files, err := os.ReadDir(u.cfg.PurgeDirectory)
+	if err != nil {
+		return err
+	}
+
+	// Move all files back to main dir.
+	for _, file := range files {
+		purgedFile := filepath.Join(u.cfg.PurgeDirectory, file.Name())
+		activeFile := filepath.Join(u.cfg.Directory, file.Name())
+		err := moveFile(purgedFile, activeFile, "", file.Type().Perm())
+		if err != nil {
+			// Only warn and continue to recover as many files as possible.
+			log.Warningf("updates: failed to roll back file %s: %w", file.Name(), err)
+		}
+	}
+
+	return nil
+}
+
+func (u *Updater) cleanupAfterUpgrade() error {
+	err := os.RemoveAll(u.cfg.PurgeDirectory)
+	if err != nil {
+		return fmt.Errorf("delete purge dir: %w", err)
+	}
+
+	err = os.RemoveAll(u.cfg.DownloadDirectory)
+	if err != nil {
+		return fmt.Errorf("delete download dir: %w", err)
+	}
+
+	return nil
+}
+
+func (u *Updater) deleteUnfinishedFiles(dir string) error {
+	entries, err := os.ReadDir(dir)
+	if err != nil {
+		return err
+	}
+
+	for _, e := range entries {
+		switch {
+		case e.IsDir():
+			// Continue.
+
+		case strings.HasSuffix(e.Name(), ".download"):
+			path := filepath.Join(dir, e.Name())
+			log.Warningf("updates: deleting unfinished download file: %s\n", path)
+			err := os.Remove(path)
+			if err != nil {
+				log.Errorf("updates: failed to delete unfinished download file %s: %s", path, err)
+			}
+
+		case strings.HasSuffix(e.Name(), ".copy"):
+			path := filepath.Join(dir, e.Name())
+			log.Warningf("updates: deleting unfinished copied file: %s\n", path)
+			err := os.Remove(path)
+			if err != nil {
+				log.Errorf("updates: failed to delete unfinished copied file %s: %s", path, err)
+			}
+		}
+	}
+
+	return nil
+}