Use ptyprocess with hcitool subprocess (#71)

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## Changelog
 
 ### [Unreleased]
+* Fix hcitool subprocess closing
 
 ## [0.12.0] - 2019-02-15
 * Changed RuuviTagReactive's time-value from local to UTC 

ruuvitag_sensor/ble_communication.py

@@ -66,29 +66,14 @@ def start(bt_device=''):
         DEVNULL = subprocess.DEVNULL if sys.version_info >= (3, 3) else open(os.devnull, 'wb')
 
         subprocess.call('sudo hciconfig %s reset' % bt_device, shell=True, stdout=DEVNULL)
-        hcitool = subprocess.Popen(['sudo', '-n', 'hcitool', 'lescan', '--duplicates'], stdout=DEVNULL)
+        hcitool = ptyprocess.PtyProcess.spawn(['sudo', '-n', 'hcitool', 'lescan', '--duplicates'])
         hcidump = ptyprocess.PtyProcess.spawn(['sudo', '-n', 'hcidump', '--raw'])
         return (hcitool, hcidump)
 
     @staticmethod
     def stop(hcitool, hcidump):
-        # import psutil here so as long as all implementations are in the same file, all will work
-        import psutil
-
         log.info('Stop receiving broadcasts')
-
-        def kill_child_processes(parent_pid):
-            try:
-                parent = psutil.Process(parent_pid)
-            except psutil.NoSuchProcess:
-                return
-
-            for process in parent.children(recursive=True):
-                subprocess.call(['sudo', '-n', 'kill', '-s', 'SIGINT', str(process.pid)])
-
-        kill_child_processes(hcitool.pid)
-        subprocess.call(['sudo', '-n', 'kill', '-s', 'SIGINT', str(hcitool.pid)])
-        kill_child_processes(hcidump.pid)
+        hcitool.close()
         hcidump.close()
 
     @staticmethod