class ChildProcessManager(object):
"""
These objects create child processes and manage their
return values.
"""
def __init__(self):
"""
Initializes the manager's state
Args:
None
"""
self.__backgroundProcesses = GenericThreadSafeList()
self.__thread = BackgroundProcessesPollingThread(self.__backgroundProcesses)
self.__thread.start()
def waitForBackgroundChildrenToTerminate(self):
"""
Waits for all the child processes running in background to terminate.
Args:
None
Returns:
Nothing
"""
self.__thread.stop()
while not self.__thread.finish() :
sleep(0.1)
@staticmethod
def runCommandInForeground(cmd, ExceptionClass):
"""
Runs a command in foreground
Args:
cmd: a string with the command's name and its arguments
ExceptionClass: the exception that will be raised if something goes wrong
Returns:
The run command's output
Raises:
ExceptionClass: this exception will be raised if something goes
wrong when running the command.
"""
p = Popen(cmd, shell=True, stdin=PIPE, stdout=PIPE, stderr=STDOUT, close_fds=True)
code = p.wait()
if (code != 0 and ExceptionClass != None) :
raise ExceptionClass(p.stdout.read())
else :
return p.stdout.read()
def runCommandInBackground(self, cmd):
"""
Runs a command in background
Args:
cmd: a string with the command's name and its arguments
Returns:
the child process' PID
"""
p = Popen(cmd, shell=False, stdin=PIPE, stdout=PIPE, stderr=STDOUT, close_fds=True)
self.__backgroundProcesses.append(p)
return p.pid
@staticmethod
def terminateProcess(pid, ExceptionClass):
"""
Sends a SIGTERM signal to a process
Args:
pid: a process' PID
ExceptionClass: the exception that will be raised if something goes wrong
Returns :
Nothing
Raises:
ExceptionClass: this exception will be raised if something goes
wrong while killing the process.
"""
ChildProcessManager.runCommandInForeground(["kill -s TERM " + str(pid)], ExceptionClass)
@staticmethod
def runCommandInForegroundAsRoot(cmd, ExceptionClass):
"""
Runs a command in foreground and as the super-user.
Args:
cmd: a string with the command's name and its arguments
ExceptionClass: the exception that will be raised if something goes wrong
Returns:
The run command's output
Raises:
ExceptionClass: this exception will be raised if something goes
wrong when running the command.
"""
password = RootPasswordHandler().getRootsPassword()
header = "echo " + password + " | sudo -S "
return ChildProcessManager.runCommandInForeground(header + cmd, ExceptionClass)