python-lttngust/lttngust/cmd.py

   1 # -*- coding: utf-8 -*-
   2 #
   3 # SPDX-License-Identifier: LGPL-2.1-only
   4 #
   5 # Copyright (C) 2015 Philippe Proulx <pproulx@efficios.com>
   6 # Copyright (C) 2014 David Goulet <dgoulet@efficios.com>
   7 # Copyright (C) 2015 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   8
   9 from __future__ import unicode_literals
  10 import lttngust.debug as dbg
  11 import struct
  12
  13
  14 # server command header
  15 _server_cmd_header_struct = struct.Struct('>QII')
  16
  17
  18 # server command header size
  19 _SERVER_CMD_HEADER_SIZE = _server_cmd_header_struct.size
  20
  21
  22 # agent protocol symbol size
  23 _LTTNG_SYMBOL_NAME_LEN = 256
  24
  25
  26 class _ServerCmdHeader(object):
  27     def __init__(self, data_size, cmd_id, cmd_version):
  28         self.data_size = data_size
  29         self.cmd_id = cmd_id
  30         self.cmd_version = cmd_version
  31
  32
  33 def _server_cmd_header_from_data(data):
  34     try:
  35         data_size, cmd_id, cmd_version = _server_cmd_header_struct.unpack(data)
  36     except (Exception) as e:
  37         dbg._pdebug('cannot decode command header: {}'.format(e))
  38         return None
  39
  40     return _ServerCmdHeader(data_size, cmd_id, cmd_version)
  41
  42
  43 class _ServerCmd(object):
  44     def __init__(self, header):
  45         self.header = header
  46
  47     @classmethod
  48     def from_data(cls, header, data):
  49         raise NotImplementedError()
  50
  51
  52 class _ServerCmdList(_ServerCmd):
  53     @classmethod
  54     def from_data(cls, header, data):
  55         return cls(header)
  56
  57
  58 class _ServerCmdEnable(_ServerCmd):
  59     _NAME_OFFSET = 8
  60     _loglevel_struct = struct.Struct('>II')
  61     # filter expression size
  62     _filter_exp_len_struct = struct.Struct('>I')
  63
  64     def __init__(self, header, loglevel, loglevel_type, name, filter_exp):
  65         super(self.__class__, self).__init__(header)
  66         self.loglevel = loglevel
  67         self.loglevel_type = loglevel_type
  68         self.name = name
  69         self.filter_expression = filter_exp
  70         dbg._pdebug('server enable command {}'.format(self.__dict__))
  71
  72     @classmethod
  73     def from_data(cls, header, data):
  74         try:
  75             loglevel, loglevel_type = cls._loglevel_struct.unpack_from(data)
  76             name_start = cls._loglevel_struct.size
  77             name_end = name_start + _LTTNG_SYMBOL_NAME_LEN
  78             data_name = data[name_start:name_end]
  79             name = data_name.rstrip(b'\0').decode()
  80
  81             filter_exp_start = name_end + cls._filter_exp_len_struct.size
  82             filter_exp_len, = cls._filter_exp_len_struct.unpack_from(
  83                 data[name_end:filter_exp_start])
  84             filter_exp_end = filter_exp_start + filter_exp_len
  85
  86             filter_exp = data[filter_exp_start:filter_exp_end].rstrip(
  87                 b'\0').decode()
  88
  89             return cls(header, loglevel, loglevel_type, name, filter_exp)
  90         except (Exception) as e:
  91             dbg._pdebug('cannot decode enable command: {}'.format(e))
  92             return None
  93
  94
  95 class _ServerCmdDisable(_ServerCmd):
  96     def __init__(self, header, name):
  97         super(self.__class__, self).__init__(header)
  98         self.name = name
  99
 100     @classmethod
 101     def from_data(cls, header, data):
 102         try:
 103             name = data.rstrip(b'\0').decode()
 104
 105             return cls(header, name)
 106         except (Exception) as e:
 107             dbg._pdebug('cannot decode disable command: {}'.format(e))
 108             return None
 109
 110
 111 class _ServerCmdRegistrationDone(_ServerCmd):
 112     @classmethod
 113     def from_data(cls, header, data):
 114         return cls(header)
 115
 116
 117 _SERVER_CMD_ID_TO_SERVER_CMD = {
 118     1: _ServerCmdList,
 119     2: _ServerCmdEnable,
 120     3: _ServerCmdDisable,
 121     4: _ServerCmdRegistrationDone,
 122 }
 123
 124
 125 def _server_cmd_from_data(header, data):
 126     if header.cmd_id not in _SERVER_CMD_ID_TO_SERVER_CMD:
 127         return None
 128
 129     return _SERVER_CMD_ID_TO_SERVER_CMD[header.cmd_id].from_data(header, data)
 130
 131
 132 _CLIENT_CMD_REPLY_STATUS_SUCCESS = 1
 133 _CLIENT_CMD_REPLY_STATUS_INVALID_CMD = 2
 134
 135
 136 class _ClientCmdReplyHeader(object):
 137     _payload_struct = struct.Struct('>I')
 138
 139     def __init__(self, status_code=_CLIENT_CMD_REPLY_STATUS_SUCCESS):
 140         self.status_code = status_code
 141
 142     def get_data(self):
 143         return self._payload_struct.pack(self.status_code)
 144
 145
 146 class _ClientCmdReplyEnable(_ClientCmdReplyHeader):
 147     pass
 148
 149
 150 class _ClientCmdReplyDisable(_ClientCmdReplyHeader):
 151     pass
 152
 153
 154 class _ClientCmdReplyList(_ClientCmdReplyHeader):
 155     _nb_events_struct = struct.Struct('>I')
 156     _data_size_struct = struct.Struct('>I')
 157
 158     def __init__(self, names, status_code=_CLIENT_CMD_REPLY_STATUS_SUCCESS):
 159         super(self.__class__, self).__init__(status_code)
 160         self.names = names
 161
 162     def get_data(self):
 163         upper_data = super(self.__class__, self).get_data()
 164         nb_events_data = self._nb_events_struct.pack(len(self.names))
 165         names_data = bytes()
 166
 167         for name in self.names:
 168             names_data += name.encode() + b'\0'
 169
 170         data_size_data = self._data_size_struct.pack(len(names_data))
 171
 172         return upper_data + data_size_data + nb_events_data + names_data
 173
 174
 175 class _ClientRegisterCmd(object):
 176     _payload_struct = struct.Struct('>IIII')
 177
 178     def __init__(self, domain, pid, major, minor):
 179         self.domain = domain
 180         self.pid = pid
 181         self.major = major
 182         self.minor = minor
 183
 184     def get_data(self):
 185         return self._payload_struct.pack(self.domain, self.pid, self.major,
 186                                          self.minor)