112 lines
3.6 KiB
Python
112 lines
3.6 KiB
Python
"""Exported method Container.attach()."""
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import fcntl
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import os
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import select
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import signal
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import socket
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import struct
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import sys
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import termios
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import tty
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CONMON_BUFSZ = 8192
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class Mixin:
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"""Publish attach() for inclusion in Container class."""
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def attach(self, eot=4, stdin=None, stdout=None):
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"""Attach to container's PID1 stdin and stdout.
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stderr is ignored.
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"""
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if stdin is None:
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stdin = sys.stdin.fileno()
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if stdout is None:
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stdout = sys.stdout.fileno()
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with self._client() as podman:
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attach = podman.GetAttachSockets(self._id)
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# This is the UDS where all the IO goes
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io_socket = attach['sockets']['io_socket']
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assert len(io_socket) <= 107,\
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'Path length for sockets too long. {} > 107'.format(
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len(io_socket)
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)
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# This is the control socket where resizing events are sent to conmon
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ctl_socket = attach['sockets']['control_socket']
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def resize_handler(signum, frame):
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"""Send the new window size to conmon.
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The method arguments are not used.
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"""
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packed = fcntl.ioctl(stdout, termios.TIOCGWINSZ,
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struct.pack('HHHH', 0, 0, 0, 0))
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rows, cols, _, _ = struct.unpack('HHHH', packed)
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with open(ctl_socket, 'w') as skt:
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# send conmon window resize message
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skt.write('1 {} {}\n'.format(rows, cols))
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def log_handler(signum, frame):
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"""Send command to reopen log to conmon.
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The method arguments are not used.
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"""
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with open(ctl_socket, 'w') as skt:
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# send conmon reopen log message
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skt.write('2\n')
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try:
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# save off the old settings for terminal
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original_attr = termios.tcgetattr(stdout)
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tty.setraw(stdin)
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# initialize containers window size
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resize_handler(None, sys._getframe(0))
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# catch any resizing events and send the resize info
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# to the control fifo "socket"
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signal.signal(signal.SIGWINCH, resize_handler)
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except termios.error:
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original_attr = None
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try:
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# Prepare socket for communicating with conmon/container
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with socket.socket(socket.AF_UNIX, socket.SOCK_SEQPACKET) as skt:
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skt.connect(io_socket)
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skt.sendall(b'\n')
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sources = [skt, stdin]
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while sources:
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readable, _, _ = select.select(sources, [], [])
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for r in readable:
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if r is skt:
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data = r.recv(CONMON_BUFSZ)
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if not data:
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sources.remove(skt)
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# Remove source marker when writing
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os.write(stdout, data[1:])
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elif r is stdin:
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data = os.read(stdin, CONMON_BUFSZ)
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if not data:
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sources.remove(stdin)
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skt.sendall(data)
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if eot in data:
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sources.clear()
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break
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else:
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raise ValueError('Unknown source in select')
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finally:
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if original_attr:
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termios.tcsetattr(stdout, termios.TCSADRAIN, original_attr)
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signal.signal(signal.SIGWINCH, signal.SIG_DFL)
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