py3 probe registration compatibility fixes

* rework `_get_kprobe_functions` to avoid unclosed blacklist warning
* rework `cleanup` to avoid changing size of dict while iterating
* make handling return of `bpf_function_name` work in py2 and py3

src/python/bcc/__init__.py

@@ -334,11 +334,12 @@ def attach_raw_socket(fn, dev):
  fn.sock = sock
 
  def _get_kprobe_functions(self, event_re):
- blacklist = set([line.rstrip().split()[1] for line in
- open("%s/../kprobes/blacklist" % TRACEFS)])
+ with open("%s/../kprobes/blacklist" % TRACEFS) as blacklist_file:
+ blacklist = set([line.rstrip().split()[1] for line in
+ blacklist_file])
  fns = []
- with open("%s/available_filter_functions" % TRACEFS) as f:
- for line in f:
+ with open("%s/available_filter_functions" % TRACEFS) as avail_file:
+ for line in avail_file:
  fn = line.rstrip().split()[0]
  if re.match(event_re, fn) and fn not in blacklist:
  fns.append(fn)
@@ -604,7 +605,7 @@ def detach_uretprobe(self, name="", sym="", addr=None):
 
  def _trace_autoload(self):
  for i in range(0, lib.bpf_num_functions(self.module)):
- func_name = lib.bpf_function_name(self.module, i)
+ func_name = str(lib.bpf_function_name(self.module, i).decode())
  if func_name.startswith("kprobe__"):
  fn = self.load_func(func_name, BPF.KPROBE)
  self.attach_kprobe(event=fn.name[8:], fn_name=fn.name)
@@ -768,14 +769,14 @@ def kprobe_poll(self, timeout = -1):
  exit()
 
  def cleanup(self):
- for k, v in self.open_kprobes.items():
+ for k, v in list(self.open_kprobes.items()):
  lib.perf_reader_free(v)
  # non-string keys here include the perf_events reader
  if isinstance(k, str):
  desc = "-:kprobes/%s" % k
  lib.bpf_detach_kprobe(desc.encode("ascii"))
  self._del_kprobe(k)
- for k, v in self.open_uprobes.items():
+ for k, v in list(self.open_uprobes.items()):
  lib.perf_reader_free(v)
  desc = "-:uprobes/%s" % k
  lib.bpf_detach_uprobe(desc.encode("ascii"))