Remove handling of KeyboardInterrupt exception (#1843)

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

src/python/bcc/__init__.py

@@ -1041,7 +1041,6 @@ class BPF(object):
         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
@@ -1063,8 +1062,6 @@ class BPF(object):
             sym_end = line.find(b":")
             msg = line[sym_end + 2:]
             return (task, int(pid), int(cpu), flags, float(ts), msg)
-        except KeyboardInterrupt:
-            exit()
 
     def trace_readline(self, nonblocking=False):
         """trace_readline(nonblocking=False)
@@ -1080,8 +1077,6 @@ class BPF(object):
             line = trace.readline(1024).rstrip()
         except IOError:
             pass
-        except KeyboardInterrupt:
-            exit()
         return line
 
     def trace_print(self, fmt=None):
@@ -1093,7 +1088,6 @@ class BPF(object):
         example: trace_print(fmt="pid {1}, msg = {5}")
         """
 
-        try:
         while True:
             if fmt:
                 fields = self.trace_fields(nonblocking=False)
@@ -1103,8 +1097,6 @@ class BPF(object):
                 line = self.trace_readline(nonblocking=False)
             print(line)
             sys.stdout.flush()
-        except KeyboardInterrupt:
-            exit()
 
     @staticmethod
     def _sym_cache(pid):
@@ -1194,13 +1186,10 @@ class BPF(object):
         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()
 
     def kprobe_poll(self, timeout = -1):
         """kprobe_poll(self)