Revision 29da446a
| b/daemons/import-export | ||
|---|---|---|
| 399 | 399 |
return GetBashCommand(buf.getvalue()) |
| 400 | 400 |
|
| 401 | 401 |
|
| 402 |
def ProcessChildIO(child, socat_stderr_read, status_file, child_logger, |
|
| 402 |
def ProcessChildIO(child, socat_stderr_read_fd, status_file, child_logger,
|
|
| 403 | 403 |
signal_notify, signal_handler): |
| 404 | 404 |
"""Handles the child processes' output. |
| 405 | 405 |
|
| 406 | 406 |
""" |
| 407 |
poller = select.poll() |
|
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assert not (signal_handler.signum - set([signal.SIGTERM, signal.SIGINT])), \ |
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"Other signals are not handled in this function" |
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| 409 |
|
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# Buffer size 0 is important, otherwise .read() with a specified length |
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# might buffer data while poll(2) won't mark its file descriptor as |
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| 412 |
# readable again. |
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socat_stderr_read = os.fdopen(socat_stderr_read_fd, "r", 0) |
|
| 408 | 414 |
|
| 409 | 415 |
script_stderr_lines = utils.LineSplitter(ProcessOutput, status_file, |
| 410 | 416 |
child_logger, False) |
| ... | ... | |
| 418 | 424 |
signal_notify.fileno(): (signal_notify, None), |
| 419 | 425 |
} |
| 420 | 426 |
|
| 427 |
poller = select.poll() |
|
| 421 | 428 |
for fd in fdmap: |
| 422 | 429 |
utils.SetNonblockFlag(fd, True) |
| 423 | 430 |
poller.register(fd, select.POLLIN) |
| ... | ... | |
| 599 | 606 |
# Pipe to receive socat's stderr output |
| 600 | 607 |
(socat_stderr_read_fd, socat_stderr_write_fd) = os.pipe() |
| 601 | 608 |
|
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# Pipe to notify on signals |
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(signal_notify_read_fd, signal_notify_write_fd) = os.pipe() |
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| 604 |
|
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# Configure signal module's notifier |
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try: |
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# This is only supported in Python 2.5 and above (some distributions |
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# backported it to Python 2.4) |
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set_wakeup_fd_fn = signal.set_wakeup_fd |
|
| 610 |
except AttributeError: |
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pass |
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else: |
|
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set_wakeup_fd_fn(signal_notify_write_fd) |
|
| 614 |
|
|
| 615 |
# Buffer size 0 is important, otherwise .read() with a specified length |
|
| 616 |
# might buffer data while poll(2) won't mark its file descriptor as |
|
| 617 |
# readable again. |
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| 618 |
socat_stderr_read = os.fdopen(socat_stderr_read_fd, "r", 0) |
|
| 619 |
signal_notify_read = os.fdopen(signal_notify_read_fd, "r", 0) |
|
| 620 |
|
|
| 621 | 609 |
# Get child process command |
| 622 | 610 |
cmd = GetCommand(mode, socat_stderr_write_fd) |
| 623 | 611 |
|
| ... | ... | |
| 626 | 614 |
# Start child process |
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child = ChildProcess(cmd, [socat_stderr_write_fd]) |
| 628 | 616 |
try: |
| 629 |
# Forward signals to child process |
|
| 630 | 617 |
def _ForwardSignal(signum, _): |
| 631 |
# Wake up poll(2) |
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os.write(signal_notify_write_fd, "\0") |
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"""Forwards signals to child process. |
|
| 633 | 619 |
|
| 634 |
# Send signal to child
|
|
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"""
|
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| 635 | 621 |
child.Kill(signum) |
| 636 | 622 |
|
| 637 |
# TODO: There is a race condition between starting the child and |
|
| 638 |
# handling the signals here. While there might be a way to work around |
|
| 639 |
# it by registering the handlers before starting the child and |
|
| 640 |
# deferring sent signals until the child is available, doing so can be |
|
| 641 |
# complicated. |
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signal_handler = utils.SignalHandler([signal.SIGTERM, signal.SIGINT], |
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handler_fn=_ForwardSignal) |
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signal_wakeup = utils.SignalWakeupFd() |
|
| 644 | 624 |
try: |
| 645 |
# Close child's side |
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utils.RetryOnSignal(os.close, socat_stderr_write_fd) |
|
| 647 |
|
|
| 648 |
if ProcessChildIO(child, socat_stderr_read, status_file, child_logger, |
|
| 649 |
signal_notify_read, signal_handler): |
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| 650 |
# The child closed all its file descriptors and there was no signal |
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# TODO: Implement timeout instead of waiting indefinitely |
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utils.RetryOnSignal(child.wait) |
|
| 625 |
# TODO: There is a race condition between starting the child and |
|
| 626 |
# handling the signals here. While there might be a way to work around |
|
| 627 |
# it by registering the handlers before starting the child and |
|
| 628 |
# deferring sent signals until the child is available, doing so can be |
|
| 629 |
# complicated. |
|
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signal_handler = utils.SignalHandler([signal.SIGTERM, signal.SIGINT], |
|
| 631 |
handler_fn=_ForwardSignal, |
|
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wakeup=signal_wakeup) |
|
| 633 |
try: |
|
| 634 |
# Close child's side |
|
| 635 |
utils.RetryOnSignal(os.close, socat_stderr_write_fd) |
|
| 636 |
|
|
| 637 |
if ProcessChildIO(child, socat_stderr_read_fd, status_file, |
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| 638 |
child_logger, signal_wakeup, |
|
| 639 |
signal_handler): |
|
| 640 |
# The child closed all its file descriptors and there was no |
|
| 641 |
# signal |
|
| 642 |
# TODO: Implement timeout instead of waiting indefinitely |
|
| 643 |
utils.RetryOnSignal(child.wait) |
|
| 644 |
finally: |
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signal_handler.Reset() |
|
| 653 | 646 |
finally: |
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signal_handler.Reset()
|
|
| 647 |
signal_wakeup.Reset()
|
|
| 655 | 648 |
finally: |
| 656 | 649 |
child.ForceQuit() |
| 657 | 650 |
|
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