add BPF.tracepoint_exists()

src/python/bcc/__init__.py

@@ -644,6 +644,11 @@ class BPF(object):
                         results.append(tp)
         return results
 
+    @staticmethod
+    def tracepoint_exists(category, event):
+        evt_dir = os.path.join(TRACEFS, "events", category, event)
+        return os.path.isdir(evt_dir)
+
     def attach_tracepoint(self, tp="", tp_re="", fn_name=""):
         """attach_tracepoint(tp="", tp_re="", fn_name="")
 

tools/tcplife.py

@@ -28,9 +28,6 @@ from socket import inet_ntop, ntohs, AF_INET, AF_INET6
 from struct import pack
 import ctypes as ct
 from time import strftime
-import os
-
-TRACEFS = "/sys/kernel/debug/tracing"
 
 # arguments
 examples = """examples:
@@ -355,7 +352,7 @@ TRACEPOINT_PROBE(tcp, tcp_set_state)
 }
 """
 
-if (os.path.exists(TRACEFS + "/events/tcp/tcp_set_state")):
+if (BPF.tracepoint_exists("tcp", "tcp_set_state")):
     bpf_text += bpf_text_tracepoint
 else:
     bpf_text += bpf_text_kprobe