Remove handling of KeyboardInterrupt exception (iovisor#1843)

KeyboardInterrupt exception is not handled anymore. It will be
propagated and handled by the caller.

src/python/bcc/__init__.py

@@ -1041,30 +1041,27 @@ def trace_fields(self, nonblocking=False):
  fields (task, pid, cpu, flags, timestamp, msg) or None if no
  line was read (nonblocking=True)
  """
- try:
- while True:
- line = self.trace_readline(nonblocking)
- if not line and nonblocking: return (None,) * 6
- # don't print messages related to lost events
- if line.startswith(b"CPU:"): continue
- task = line[:16].lstrip()
- line = line[17:]
- ts_end = line.find(b":")
- pid, cpu, flags, ts = line[:ts_end].split()
- cpu = cpu[1:-1]
- # line[ts_end:] will have ": [sym_or_addr]: msgs"
- # For trace_pipe debug output, the addr typically
- # is invalid (e.g., 0x1). For kernel 4.12 or earlier,
- # if address is not able to match a kernel symbol,
- # nothing will be printed out. For kernel 4.13 and later,
- # however, the illegal address will be printed out.
- # Hence, both cases are handled here.
- line = line[ts_end + 1:]
- sym_end = line.find(b":")
- msg = line[sym_end + 2:]
- return (task, int(pid), int(cpu), flags, float(ts), msg)
- except KeyboardInterrupt:
- exit()
+ while True:
+ line = self.trace_readline(nonblocking)
+ if not line and nonblocking: return (None,) * 6
+ # don't print messages related to lost events
+ if line.startswith(b"CPU:"): continue
+ task = line[:16].lstrip()
+ line = line[17:]
+ ts_end = line.find(b":")
+ pid, cpu, flags, ts = line[:ts_end].split()
+ cpu = cpu[1:-1]
+ # line[ts_end:] will have ": [sym_or_addr]: msgs"
+ # For trace_pipe debug output, the addr typically
+ # is invalid (e.g., 0x1). For kernel 4.12 or earlier,
+ # if address is not able to match a kernel symbol,
+ # nothing will be printed out. For kernel 4.13 and later,
+ # however, the illegal address will be printed out.
+ # Hence, both cases are handled here.
+ line = line[ts_end + 1:]
+ sym_end = line.find(b":")
+ msg = line[sym_end + 2:]
+ return (task, int(pid), int(cpu), flags, float(ts), msg)
 
  def trace_readline(self, nonblocking=False):
  """trace_readline(nonblocking=False)
@@ -1080,8 +1077,6 @@ def trace_readline(self, nonblocking=False):
  line = trace.readline(1024).rstrip()
  except IOError:
  pass
- except KeyboardInterrupt:
- exit()
  return line
 
  def trace_print(self, fmt=None):
@@ -1093,18 +1088,15 @@ def trace_print(self, fmt=None):
  example: trace_print(fmt="pid {1}, msg = {5}")
  """
 
- try:
- while True:
- if fmt:
- fields = self.trace_fields(nonblocking=False)
- if not fields: continue
- line = fmt.format(*fields)
- else:
- line = self.trace_readline(nonblocking=False)
- print(line)
- sys.stdout.flush()
- except KeyboardInterrupt:
- exit()
+ while True:
+ if fmt:
+ fields = self.trace_fields(nonblocking=False)
+ if not fields: continue
+ line = fmt.format(*fields)
+ else:
+ line = self.trace_readline(nonblocking=False)
+ print(line)
+ sys.stdout.flush()
 
  @staticmethod
  def _sym_cache(pid):
@@ -1194,13 +1186,10 @@ def perf_buffer_poll(self, timeout = -1):
  Poll from all open perf ring buffers, calling the callback that was
  provided when calling open_perf_buffer for each entry.
  """
- try:
- readers = (ct.c_void_p * len(self.perf_buffers))()
- for i, v in enumerate(self.perf_buffers.values()):
- readers[i] = v
- lib.perf_reader_poll(len(readers), readers, timeout)
- except KeyboardInterrupt:
- exit()
+ readers = (ct.c_void_p * len(self.perf_buffers))()
+ for i, v in enumerate(self.perf_buffers.values()):
+ readers[i] = v
+ lib.perf_reader_poll(len(readers), readers, timeout)
 
  def kprobe_poll(self, timeout = -1):
  """kprobe_poll(self)