Add logrotate conflict detection

client/internal/debug/debug.go

@@ -1043,7 +1043,8 @@ func (g *BundleGenerator) addRotatedLogFiles(logDir string) {
 		return
 	}
 
-	pattern := filepath.Join(logDir, "client-*.log.gz")
+	// This regex will match both logs rotated by us and logrotate on linux
+	pattern := filepath.Join(logDir, "client*.log*.gz")
 	files, err := filepath.Glob(pattern)
 	if err != nil {
 		log.Warnf("failed to glob rotated logs: %v", err)

util/log.go

@@ -59,7 +59,18 @@ func InitLogger(logger *log.Logger, logLevel string, logs ...string) error {
 		case "":
 			logger.Warnf("empty log path received: %#v", logPath)
 		default:
-			writers = append(writers, newRotatedOutput(logPath))
+			conflict, configPath := FindFirstLogrotateConflict()
+			if conflict {
+				logger.Warnf("logrotation conflict detected in: %#v, rotation is disabled", configPath)
+				file, err := openOrCreateFile(logPath)
+				if err != nil {
+					logger.Errorf("Failed opening log file: %s", err)
+					return err
+				}
+				writers = append(writers, file)
+			} else {
+				writers = append(writers, newRotatedOutput(logPath))
+			}
 		}
 	}
 

util/logrotate_linux.go

@@ -0,0 +1,89 @@
+//go:build linux
+
+package util
+
+import (
+	"bufio"
+	"errors"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+
+	log "github.com/sirupsen/logrus"
+)
+
+const (
+	defaultLogrotateConfPath = "/etc/logrotate.conf"
+	defaultLogrotateConfDir  = "/etc/logrotate.d"
+	netbirdString            = "netbird"
+)
+
+// FindLogrotateConflicts scans the standard logrotate locations for
+// indications of conflict with netbird. It returns true and the config file
+// path if a conflict was found.
+func FindFirstLogrotateConflict() (bool, string) {
+	for _, f := range listLogrotateConfigs() {
+		present, err := scanLogrotateFile(f, netbirdString)
+		if err != nil {
+			if !errors.Is(err, fs.ErrNotExist) {
+				log.Debugf("scan %s: %v", f, err)
+			}
+			continue
+		}
+		if present {
+			return present, f
+		}
+	}
+	return false, ""
+}
+
+// listLogrotateConfigs returns all config files for logrotate.
+func listLogrotateConfigs() []string {
+	files := []string{defaultLogrotateConfPath}
+	entries, err := os.ReadDir(defaultLogrotateConfDir)
+	if err != nil {
+		return files
+	}
+	for _, e := range entries {
+		if e.IsDir() {
+			continue
+		}
+		files = append(files, filepath.Join(defaultLogrotateConfDir, e.Name()))
+	}
+	return files
+}
+
+// scanLogrotateFile reads a config and reports if a non-comment line
+// contains the given substring.
+func scanLogrotateFile(path string, substring string) (bool, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return false, err
+	}
+	defer func() {
+		if err := f.Close(); err != nil {
+			log.Debugf("close %s: %v", path, err)
+		}
+	}()
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := strings.TrimSpace(stripLogrotateComment(scanner.Text()))
+		if line == "" {
+			continue
+		}
+		if strings.Contains(line, substring) {
+			return true, nil
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		return false, err
+	}
+	return false, nil
+}
+
+func stripLogrotateComment(line string) string {
+	before, _, _ := strings.Cut(line, "#")
+	return before
+}

util/logrotate_nonlinux.go

@@ -0,0 +1,11 @@
+//go:build !linux
+
+package util
+
+// FindLogrotateConflicts scans the standard logrotate locations and returns
+// true and the first config file that contains a non-comment line indicating
+// it's configured for netbird.
+// Will always return false for non-linux device.
+func FindFirstLogrotateConflict() (bool, string) {
+	return false, ""
+}