diff --git a/common/rdr/Exception.h b/common/rdr/Exception.h
index f533dcc..62f452b 100644
--- a/common/rdr/Exception.h
+++ b/common/rdr/Exception.h
@@ -43,15 +43,15 @@
   }; 
 
   struct TimedOut : public Exception {
-    TimedOut(const char* s="Timed out") : Exception(s) {}
+    TimedOut(const char* s="Timed out") : Exception("%s", s) {}
   };
  
   struct EndOfStream : public Exception {
-    EndOfStream(const char* s="End of stream") : Exception(s) {}
+    EndOfStream(const char* s="End of stream") : Exception("%s", s) {}
   };
 
   struct FrameException : public Exception {
-    FrameException(const char* s="Frame exception") : Exception(s) {}
+    FrameException(const char* s="Frame exception") : Exception("%s", s) {}
   };
 
 }
diff --git a/common/rdr/FileInStream.cxx b/common/rdr/FileInStream.cxx
index 18a9169..6d23aa2 100644
--- a/common/rdr/FileInStream.cxx
+++ b/common/rdr/FileInStream.cxx
@@ -72,7 +72,7 @@
     size_t n = fread((U8 *)end, b + sizeof(b) - end, 1, file);
     if (n < 1) {
       if (n < 0 || ferror(file))
-        throw Exception(strerror(errno));
+        throw SystemException("fread", errno);
       if (feof(file))
         throw EndOfStream();
       if (n == 0) { return 0; }
diff --git a/common/rdr/TLSException.cxx b/common/rdr/TLSException.cxx
index 3d39d79..bf8e97a 100644
--- a/common/rdr/TLSException.cxx
+++ b/common/rdr/TLSException.cxx
@@ -34,15 +34,8 @@
 
 #ifdef HAVE_GNUTLS
 TLSException::TLSException(const char* s, int err_)
-  : Exception(s), err(err_)
+  : Exception("%s: %s (%d)", s, gnutls_strerror(err), err), err(err_)
 {
-  strncat(str_, ": ", len-1-strlen(str_));
-  strncat(str_, gnutls_strerror(err), len-1-strlen(str_));
-  strncat(str_, " (", len-1-strlen(str_));
-  char buf[20];
-  sprintf(buf,"%d",err);
-  strncat(str_, buf, len-1-strlen(str_));
-  strncat(str_, ")", len-1-strlen(str_));
 }
 #endif /* HAVE_GNUTLS */