def __execute(self, stdout):
"""Executes the command."""
# Configure the standard I/O file descriptors
self.__configure_stdio(stdout)
# Fork the process -->
fork_lock = threading.Lock()
with fork_lock:
# Allocate all resources before fork() to guarantee that we will
# be able to control the process execution.
# Execution thread -->
poll = psys.poll.Poll()
try:
self.__communication_thread = threading.Thread(
target=self.__communication_thread_func,
args=(fork_lock, poll))
self.__communication_thread.daemon = True
self.__communication_thread.start()
except:
poll.close()
raise
# Execution thread <--
# Wait thread -->
try:
self.__termination_fd, termination_fd = os.pipe()
except Exception as e:
raise Error("Unable to create a pipe: {0}.", psys.e(e))
try:
self.__wait_thread = threading.Thread(
target=self.__wait_pid_thread,
args=[fork_lock, termination_fd])
self.__wait_thread.daemon = True
self.__wait_thread.start()
except BaseException as error:
try:
eintr_retry(os.close)(termination_fd)
except Exception as e:
LOG.error("Unable to close a pipe: %s.", psys.e(e))
raise error
# Wait thread <--
self.__pid = os.fork()
if self.__pid:
self.__state = _PROCESS_STATE_RUNNING
else:
self.__child()
def __execute(self, stdout):
"""Executes the command."""
# Configure the standard I/O file descriptors
self.__configure_stdio(stdout)
# Fork the process -->
fork_lock = threading.Lock()
with fork_lock:
# Allocate all resources before fork() to guarantee that we will
# be able to control the process execution.
# Execution thread -->
poll = psys.poll.Poll()
try:
self.__communication_thread = threading.Thread(
target=self.__communication_thread_func,
args=(fork_lock, poll))
self.__communication_thread.daemon = True
self.__communication_thread.start()
except:
poll.close()
raise
# Execution thread <--
# Wait thread -->
try:
self.__termination_fd, termination_fd = os.pipe()
except Exception as e:
raise Error("Unable to create a pipe: {0}.", psys.e(e))
try:
self.__wait_thread = threading.Thread(
target=self.__wait_pid_thread, args=[fork_lock, termination_fd])
self.__wait_thread.daemon = True
self.__wait_thread.start()
except BaseException as error:
try:
eintr_retry(os.close)(termination_fd)
except Exception as e:
LOG.error("Unable to close a pipe: %s.", psys.e(e))
raise error
# Wait thread <--
self.__pid = os.fork()
if self.__pid:
self.__state = _PROCESS_STATE_RUNNING
else:
self.__child()
def __communication_thread_func(self, fork_lock, poll):
"""A thread in which we communicate with the process."""
try:
# Wait for fork() process completion
with fork_lock:
pass
# Work only if we've successfully forked
if self.__pid is not None:
try:
self.__communicate(poll)
finally:
self.__close()
self.__state = _PROCESS_STATE_TERMINATED
except Exception as e:
LOG.exception("Execution thread crashed.")
if self.__pid is not None:
self.__error = e
finally:
poll.close()
def __communication_thread_func(self, fork_lock, poll):
"""A thread in which we communicate with the process."""
try:
# Wait for fork() process completion
with fork_lock:
pass
# Work only if we've successfully forked
if self.__pid is not None:
try:
self.__communicate(poll)
finally:
self.__close()
self.__state = _PROCESS_STATE_TERMINATED
except Exception as e:
LOG.exception("Execution thread crashed.")
if self.__pid is not None:
self.__error = e
finally:
poll.close()
