address pr comment

libbeat/processors/cache/file_store.go

@@ -26,6 +26,7 @@ import (
 	"io/fs"
 	"os"
 	"path/filepath"
+	"strings"
 	"sync"
 	"time"
 
@@ -224,7 +225,7 @@ func (c *fileStore) writeState(final bool) {
 		}
 		return
 	}
-	f, err := os.CreateTemp(filepath.Dir(c.path), "")
+	f, err := os.CreateTemp(filepath.Dir(c.path), cleanFilename(c.id)+"-*.tmp")
 	if err != nil {
 		c.log.Errorw("failed to open file to write state", "error", err)
 		return
@@ -270,3 +271,24 @@ func (c *fileStore) writeState(final bool) {
 		}
 	}
 }
+
+// cleanFilename replaces illegal printable characters (and space or dot) in
+// filenames, with underscore.
+func cleanFilename(s string) string {
+	return pathCleaner.Replace(s)
+}
+
+var pathCleaner = strings.NewReplacer(
+	"/", "_",
+	"<", "_",
+	">", "_",
+	":", "_",
+	`"`, "_",
+	"/", "_",
+	`\`, "_",
+	"|", "_",
+	"?", "_",
+	"*", "_",
+	".", "_",
+	" ", "_",
+)