core-admin-client/qubesadmin/tools/qvm_run.py
Marek Marczykowski-Górecki 50bd9f5fab
tools/qvm-run: fix handling small data blocks
When data block is smaller than 4096 (and no EOF is reached), python's
io.read() will call read(2) again to get more data. This may deadlock if
the other end of connection will write anything only after receiveing
data (which is the case for qubes.Filecopy).
Disable this buffering by using syscall wrappers directly. To not affect
performance that much, increase buffer size to 64k.

Fixes QubesOS/qubes-issues#2948
2017-08-02 02:43:03 +02:00

211 lines
7.6 KiB
Python

# -*- encoding: utf8 -*-
#
# The Qubes OS Project, http://www.qubes-os.org
#
# Copyright (C) 2017 Marek Marczykowski-Górecki
# <marmarek@invisiblethingslab.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with this program; if not, see <http://www.gnu.org/licenses/>.
''' qvm-run tool'''
import os
import sys
import subprocess
import multiprocessing
import qubesadmin.tools
import qubesadmin.exc
parser = qubesadmin.tools.QubesArgumentParser(vmname_nargs='+')
parser.add_argument('--user', '-u', metavar='USER',
help='run command in a qube as USER (available only from dom0)')
parser.add_argument('--autostart', '--auto', '-a',
action='store_true', default=True,
help='option ignored, this is default')
parser.add_argument('--no-autostart', '--no-auto', '-n',
action='store_false',
help='do not autostart qube')
parser.add_argument('--pass-io', '-p',
action='store_true', dest='passio', default=False,
help='pass stdio from remote program')
parser.add_argument('--localcmd', metavar='COMMAND',
help='with --pass-io, pass stdio to the given program')
parser.add_argument('--gui',
action='store_true', default=True,
help='run the command with GUI (default on)')
parser.add_argument('--no-gui', '--nogui',
action='store_false', dest='gui',
help='run the command without GUI')
parser.add_argument('--colour-output', '--color-output', metavar='COLOUR',
action='store', dest='color_output', default=None,
help='mark the qube output with given ANSI colour (ie. "31" for red)')
parser.add_argument('--colour-stderr', '--color-stderr', metavar='COLOUR',
action='store', dest='color_stderr', default=None,
help='mark the qube stderr with given ANSI colour (ie. "31" for red)')
parser.add_argument('--no-colour-output', '--no-color-output',
action='store_false', dest='color_output',
help='disable colouring the stdio')
parser.add_argument('--no-colour-stderr', '--no-color-stderr',
action='store_false', dest='color_stderr',
help='disable colouring the stderr')
parser.add_argument('--filter-escape-chars',
action='store_true', dest='filter_esc',
default=os.isatty(sys.stdout.fileno()),
help='filter terminal escape sequences (default if output is terminal)')
parser.add_argument('--no-filter-escape-chars',
action='store_false', dest='filter_esc',
help='do not filter terminal escape sequences; DANGEROUS when output is a'
' terminal emulator')
parser.add_argument('--service',
action='store_true', dest='service',
help='run a qrexec service (named by COMMAND) instead of shell command')
parser.add_argument('cmd', metavar='COMMAND',
help='command to run')
def copy_stdin(stream):
'''Copy stdin to *stream*'''
# multiprocessing.Process have sys.stdin connected to /dev/null
os.set_blocking(0, True)
for data in iter(lambda: os.read(0, 65536), b''):
if data is None:
break
stream.write(data)
stream.flush()
stream.close()
def main(args=None, app=None):
'''Main function of qvm-run tool'''
args = parser.parse_args(args, app=app)
if args.color_output is None and args.filter_esc:
args.color_output = '31'
if args.color_output is None and os.isatty(sys.stderr.fileno()):
args.color_stderr = 31
if len(args.domains) > 1 and args.passio and not args.localcmd:
parser.error('--passio cannot be used when more than 1 qube is chosen '
'and no --localcmd is used')
if args.localcmd and not args.passio:
parser.error('--localcmd have no effect without --pass-io')
if args.color_output and not args.filter_esc:
parser.error('--color-output must be used with --filter-escape-chars')
retcode = 0
run_kwargs = {}
if not args.passio:
run_kwargs['stdout'] = subprocess.DEVNULL
run_kwargs['stderr'] = subprocess.DEVNULL
else:
# connect process output to stdout/err directly if --pass-io is given
run_kwargs['stdout'] = None
run_kwargs['stderr'] = None
if isinstance(args.app, qubesadmin.app.QubesLocal) and \
not args.passio and not args.localcmd and args.service:
# wait=False works only in dom0; but it's still useful, to save on
# simultaneous vchan connections
run_kwargs['wait'] = False
verbose = args.verbose - args.quiet
if args.passio:
verbose -= 1
if args.color_output:
sys.stdout.write('\033[0;{}m'.format(args.color_output))
sys.stdout.flush()
if args.color_stderr:
sys.stderr.write('\033[0;{}m'.format(args.color_stderr))
sys.stderr.flush()
copy_proc = None
try:
procs = []
for vm in args.domains:
if not args.autostart and not vm.is_running():
continue
try:
if verbose > 0:
if args.color_output:
print('\033[0mRunning \'{}\' on {}\033[0;{}m'.format(
args.cmd, vm.name, args.color_output),
file=sys.stderr)
else:
print('Running \'{}\' on {}'.format(args.cmd, vm.name),
file=sys.stderr)
if args.gui:
wait_session = vm.run_service('qubes.WaitForSession',
stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
wait_session.communicate(vm.default_user.encode())
if args.service:
proc = vm.run_service(args.cmd,
user=args.user,
localcmd=args.localcmd,
filter_esc=args.filter_esc,
**run_kwargs)
else:
proc = vm.run_service('qubes.VMShell',
user=args.user,
localcmd=args.localcmd,
filter_esc=args.filter_esc,
**run_kwargs)
proc.stdin.write(vm.prepare_input_for_vmshell(args.cmd))
proc.stdin.flush()
if args.passio and not args.localcmd:
copy_proc = multiprocessing.Process(target=copy_stdin,
args=(proc.stdin,))
copy_proc.start()
# keep the copying process running
proc.stdin.close()
procs.append(proc)
except qubesadmin.exc.QubesException as e:
if args.color_output:
sys.stdout.write('\033[0m')
sys.stdout.flush()
vm.log.error(str(e))
return -1
for proc in procs:
retcode = max(retcode, proc.wait())
finally:
if args.color_output:
sys.stdout.write('\033[0m')
sys.stdout.flush()
if args.color_stderr:
sys.stderr.write('\033[0m')
sys.stderr.flush()
if copy_proc is not None:
copy_proc.terminate()
return retcode
if __name__ == '__main__':
sys.exit(main())