Fix bytes - strings confusion in trace tool

tools/trace.py

@@ -13,7 +13,7 @@
 from __future__ import print_function
 from bcc import BPF, USDT, StrcmpRewrite
 from functools import partial
-from time import sleep, strftime
+from time import strftime
 import time
 import argparse
 import re
@@ -74,7 +74,12 @@ def __init__(self, probe, string_size, kernel_stack, user_stack,
  self.probe_name = re.sub(r'[^A-Za-z0-9_]', '_',
  self.probe_name)
  self.cgroup_map_name = cgroup_map_name
- self.name = name
+ if name is None:
+ # An empty bytestring is always contained in the command
+ # name so this will always succeed.
+ self.name = b''
+ else:
+ self.name = name.encode('ascii')
  self.msg_filter = msg_filter
  # compiler can generate proper codes for function
  # signatures with "syscall__" prefix
@@ -275,7 +280,7 @@ def _parse_action(self, action):
  "$pid": "(unsigned)(bpf_get_current_pid_tgid() & 0xffffffff)",
  "$tgid": "(unsigned)(bpf_get_current_pid_tgid() >> 32)",
  "$cpu": "bpf_get_smp_processor_id()",
- "$task" : "((struct task_struct *)bpf_get_current_task())"
+ "$task": "((struct task_struct *)bpf_get_current_task())"
  }
 
  def _rewrite_expr(self, expr):
@@ -372,7 +377,7 @@ def _generate_data_decl(self):
  self.stacks_name = "%s_stacks" % self.probe_name
  stack_type = "BPF_STACK_TRACE" if self.build_id_enabled is False \
  else "BPF_STACK_TRACE_BUILDID"
- stack_table = "%s(%s, 1024);" % (stack_type,self.stacks_name) \
+ stack_table = "%s(%s, 1024);" % (stack_type, self.stacks_name) \
  if (self.kernel_stack or self.user_stack) else ""
  data_fields = ""
  for i, field_type in enumerate(self.types):
@@ -596,12 +601,12 @@ 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
- if self.name and bytes(self.name) not in event.comm:
+ if self.name not in event.comm:
  return
  values = map(lambda i: getattr(event, "v%d" % i),
  range(0, len(self.values)))
  msg = self._format_message(bpf, event.tgid, values)
- if self.msg_filter and bytes(self.msg_filter) not in msg:
+ if self.msg_filter and self.msg_filter not in msg:
  return
  if Probe.print_time:
  time = strftime("%H:%M:%S") if Probe.use_localtime else \
@@ -762,17 +767,17 @@ def __init__(self):
  help="print time column")
  parser.add_argument("-C", "--print_cpu", action="store_true",
  help="print CPU id")
- parser.add_argument("-c", "--cgroup-path", type=str, \
- metavar="CGROUP_PATH", dest="cgroup_path", \
+ parser.add_argument("-c", "--cgroup-path", type=str,
+ metavar="CGROUP_PATH", dest="cgroup_path",
  help="cgroup path")
  parser.add_argument("-n", "--name", type=str,
  help="only print process names containing this name")
  parser.add_argument("-f", "--msg-filter", type=str, dest="msg_filter",
  help="only print the msg of event containing this string")
  parser.add_argument("-B", "--bin_cmp", action="store_true",
  help="allow to use STRCMP with binary values")
- parser.add_argument('-s', "--sym_file_list", type=str, \
- metavar="SYM_FILE_LIST", dest="sym_file_list", \
+ parser.add_argument('-s', "--sym_file_list", type=str,
+ metavar="SYM_FILE_LIST", dest="sym_file_list",
  help="coma separated list of symbol files to use \
  for symbol resolution")
  parser.add_argument("-K", "--kernel-stack",
@@ -868,9 +873,9 @@ def _main_loop(self):
  # Print header
  if self.args.timestamp or self.args.time:
  col_fmt = "%-17s " if self.args.unix_timestamp else "%-8s "
- print(col_fmt % "TIME", end="");
+ print(col_fmt % "TIME", end="")
  if self.args.print_cpu:
- print("%-3s " % "CPU", end="");
+ print("%-3s " % "CPU", end="")
  print("%-7s %-7s %-15s %-16s %s" %
  ("PID", "TID", "COMM", "FUNC",
  "-" if not all_probes_trivial else ""))