tools/trace: Remove explicit ctype cast

tools/trace.py

@@ -321,44 +321,6 @@ def _rewrite_expr(self, expr):
  expr = expr.replace(alias, replacement)
  return expr
 
- p_type = {"u": ct.c_uint, "d": ct.c_int, "lu": ct.c_ulong,
- "ld": ct.c_long,
- "llu": ct.c_ulonglong, "lld": ct.c_longlong,
- "hu": ct.c_ushort, "hd": ct.c_short,
- "x": ct.c_uint, "lx": ct.c_ulong, "llx": ct.c_ulonglong,
- "c": ct.c_ubyte,
- "K": ct.c_ulonglong, "U": ct.c_ulonglong}
-
- def _generate_python_field_decl(self, idx, fields):
- field_type = self.types[idx]
- if field_type == "s":
- ptype = ct.c_char * self.string_size
- else:
- ptype = Probe.p_type[field_type]
- fields.append(("v%d" % idx, ptype))
-
- def _generate_python_data_decl(self):
- self.python_struct_name = "%s_%d_Data" % \
- (self._display_function(), self.probe_num)
- fields = []
- if self.time_field:
- fields.append(("timestamp_ns", ct.c_ulonglong))
- if self.print_cpu:
- fields.append(("cpu", ct.c_int))
- fields.extend([
- ("tgid", ct.c_uint),
- ("pid", ct.c_uint),
- ("comm", ct.c_char * 16) # TASK_COMM_LEN
- ])
- for i in range(0, len(self.types)):
- self._generate_python_field_decl(i, fields)
- if self.kernel_stack:
- fields.append(("kernel_stack_id", ct.c_int))
- if self.user_stack:
- fields.append(("user_stack_id", ct.c_int))
- return type(self.python_struct_name, (ct.Structure,),
- dict(_fields_=fields))
-
  c_type = {"u": "unsigned int", "d": "int",
  "lu": "unsigned long", "ld": "long",
  "llu": "unsigned long long", "lld": "long long",
@@ -629,9 +591,7 @@ def print_aggregate_events(self):
  print("%s-->COUNT %d\n\n" % (k, v), end="")
 
  def print_event(self, bpf, cpu, data, size):
- # Cast as the generated structure type and display
- # according to the format string in the probe.
- event = ct.cast(data, ct.POINTER(self.python_struct)).contents
+ event = bpf[self.events_name].event(data)
  if self.name not in event.comm:
  return
  values = list(map(lambda i: getattr(event, "v%d" % i),
@@ -682,7 +642,6 @@ def attach(self, bpf, verbose):
  self._attach_k(bpf)
  else:
  self._attach_u(bpf)
- self.python_struct = self._generate_python_data_decl()
  callback = partial(self.print_event, bpf)
  bpf[self.events_name].open_perf_buffer(callback,
  page_cnt=self.page_cnt)