Source Code for Module sparked.hardware.hal

  1  # Copyright (c) 2010 Arjan Scherpenisse 
  2  # See LICENSE for details. 
  3   
  4  """ 
  5  Hardware monitoring classes based on linux' HAL system. 
  6  """ 
  7   
  8  import os 
  9  import dbus 
 10  import glob 
 11   
 12  from twisted.application import service 
 13  from twisted.internet import reactor 
 14   
 15   
 16  DBUS_INTERFACE = "org.freedesktop.DBus" 
 17  HAL_INTERFACE = 'org.freedesktop.Hal' 
 18  HAL_DEVICE_INTERFACE = 'org.freedesktop.Hal.Device' 
 19  HAL_MANAGER_INTERFACE = 'org.freedesktop.Hal.Manager' 
 20  HAL_MANAGER_UDI = '/org/freedesktop/Hal/Manager' 
 21   
 22  # The following properties get automatically read upon device insertion. 
 23  # See http://people.freedesktop.org/~dkukawka/hal-spec-git/hal-spec.html 
 24  # 
 25  HAL_SUBSYSTEM_PROPERTIES = { 
 26      'serial': ['originating_device', 'device', 'port', 'type'], 
 27      'video4linux': ['device', 'version'], 
 28      'input': ['device'] 
 29      } 
 30   
 31   
 32 -class HardwareMonitor (service.Service): 
 33      """ 
 34      A generic hardware monitor class based on HAL. Listens for device add/remove filtered on a specific subsystem. 
 35   
 36      @ivar subsystem: The HAL subsystem type to monitor. E.g. serial, video4linux, ... 
 37      @ivar deviceInfo: dict which will be filled with device information. Key is the HAL UDI (Unique Device Identifier). 
 38      @ivar uniquePath: If set, point to a directory where the symlinks to the unique devices will be made, e.g. /dev/serial/by-id/ 
 39      @ivar events: If set, point to a L{sparked.events.EventDispatcher} to dispatch <subsystem>-{added,removed} events to. 
 40      """ 
 41   
 42      subsystem = None 
 43      deviceInfo = None 
 44      uniquePath = None 
 45      events = None 
 46   
 47   
 48 -    def startService(self): 
 49          self.deviceInfo = {} 
 50          self.bus = dbus.SystemBus() 
 51          self.bus.add_signal_receiver(self._halDeviceAdded, 
 52                                  dbus_interface=HAL_MANAGER_INTERFACE, 
 53                                  signal_name='DeviceAdded') 
 54          self.bus.add_signal_receiver(self._halDeviceRemoved, 
 55                                  dbus_interface=HAL_MANAGER_INTERFACE, 
 56                                  signal_name='DeviceRemoved') 
 57   
 58          self.manager = self._getHalInterface(HAL_MANAGER_UDI, HAL_MANAGER_INTERFACE) 
 59   
 60          for udi in self.manager.FindDeviceByCapability(self.subsystem): 
 61              reactor.callLater(0, self._halDeviceAdded, udi) 
 62   
 63   
 64 -    def stopService(self): 
 65          udis = self.deviceInfo.keys() 
 66          for udi in udis: 
 67              self._halDeviceRemoved(udi) 
 68   
 69   
 70 -    def _getHalInterface(self, udi, interface=HAL_DEVICE_INTERFACE): 
 71          obj = self.bus.get_object(HAL_INTERFACE, udi) 
 72          return dbus.Interface(obj, interface) 
 73   
 74   
 75 -    def _halDeviceAdded(self, udi): 
 76          udi = str(udi) 
 77          if not self.manager.DeviceExists(udi): 
 78              # device has been removed 
 79              return 
 80          device = self._getHalInterface(udi) 
 81   
 82          if not device.QueryCapability(self.subsystem): 
 83              # wrong device 
 84              return 
 85   
 86          self.deviceInfo[udi] = {"udi": udi} 
 87   
 88          if self.subsystem in HAL_SUBSYSTEM_PROPERTIES: 
 89              for k in HAL_SUBSYSTEM_PROPERTIES[self.subsystem]: 
 90                  self.deviceInfo[udi][k] = str(device.GetProperty(self.subsystem+'.'+k)) 
 91   
 92          if "device" in self.deviceInfo[udi] and self.uniquePath: 
 93              by_id = [p for p in glob.glob(os.path.join(self.uniquePath, "*")) 
 94                       if os.path.realpath(p) == self.deviceInfo[udi]["device"]] 
 95              if by_id: 
 96                  self.deviceInfo[udi]["unique_path"] = by_id[0] 
 97   
 98          if self.events: 
 99              self.events.dispatch("%s-added" % self.subsystem, info=self.deviceInfo[udi]) 
100   
101          self.deviceAdded(self.deviceInfo[udi]) 
102          return device 
103   
104   
105 -    def _halDeviceRemoved(self, udi): 
106          udi = str(udi) 
107          if udi not in self.deviceInfo: 
108              return 
109   
110          if self.events: 
111              self.events.dispatch("%s-removed" % self.subsystem, info=self.deviceInfo[udi]) 
112   
113          self.deviceRemoved(self.deviceInfo[udi]) 
114          del self.deviceInfo[udi] 
115   
116   
117 -    def deviceAdded(self, info): 
118          """ 
119          This method will be called when a device has been added. If 
120          you subclass this class, this method can be overruled to do 
121          application-specific stuff. 
122          """ 
123   
124   
125 -    def deviceRemoved(self, info): 
126          """ 
127          This method will be called when a device has been removed. If 
128          you subclass this class, this method can be overruled to do 
129          application-specific stuff. 
130          """ 
131