autopkgtest 3.6jessie1 / usr / bin / adt-virt-lxc

#!/usr/bin/python3
#
# adt-virt-lxc is part of autopkgtest
# autopkgtest is a tool for testing Debian binary packages
#
# autopkgtest is Copyright (C) 2006-2014 Canonical Ltd.
#
# adt-virt-lxc was derived from adt-virt-schroot and modified to suit LXC by
# Robie Basak <robie.basak@canonical.com>.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#
# See the file CREDITS for a full list of credits information (often
# installed as /usr/share/doc/autopkgtest/CREDITS).

import sys
import os
import string
import random
import subprocess
import time
import tempfile
import shutil
import argparse

try:
    our_base = os.environ['AUTOPKGTEST_BASE'] + '/lib'
except KeyError:
    our_base = '/usr/share/autopkgtest/python'
sys.path.insert(1, our_base)

import VirtSubproc
import adtlog


capabilities = ['revert', 'revert-full-system', 'root-on-testbed',
                'isolation-container']

args = None
lxc_container_name = None
normal_user = None
shared_dir = None


def parse_args():
    global args

    parser = argparse.ArgumentParser(fromfile_prefix_chars='@')

    parser.add_argument('-d', '--debug', action='store_true',
                        help='Enable debugging output')
    parser.add_argument('--eatmydata', action='store_true',
                        help='Use eatmydata inside the container to improve performance')
    parser.add_argument('-e', '--ephemeral', action='store_true',
                        help='Use ephemeral overlays instead of cloning (much '
                        'faster, but might cause errors in some corner cases)')
    parser.add_argument('-s', '--sudo', action='store_true',
                        help='Run lxc-* commands with sudo; use if you run '
                        'adt-run as normal user')
    parser.add_argument('template', help='LXC container name that will be '
                        'used as a template')
    args = parser.parse_args()
    if args.debug:
        adtlog.verbosity = 2


def sudoify(command):
    '''Prepend sudo to command with the --sudo option'''

    if args.sudo:
        return ['sudo'] + command
    else:
        return command


def check_for_eatmydata(container, template_name):
    with open('/dev/null', 'wb') as null:
        result = VirtSubproc.execute_timeout(
            None, 10, sudoify(['lxc-attach', '--name', container, '--', 'sh', '-c',
                               'type eatmydata']),
            close_fds=True, stdout=null, stderr=null)
    if result:
        raise RuntimeError(
            ('Container %s does not contain eatmydata, which is required '
             'for the --eatmydata option.' % repr(template_name))
        )


def get_available_lxc_container_name():
    '''Return an LXC container name that isn't already taken.

    There is a race condition between returning this name and creation of
    the container. Ideally lxc-start-ephemeral would generate a name in a
    race free way and return the name used in machine-readable way, so that
    this function would not be necessary. See LP: #1197754.
    '''
    while True:
        # generate random container name
        rnd = [random.choice(string.ascii_lowercase) for i in range(6)]
        candidate = 'adt-virt-lxc-' + ''.join(rnd)

        containers = VirtSubproc.check_exec(sudoify(['lxc-ls']), outp=True,
                                            timeout=10)
        if candidate not in containers:
            return candidate


def wait_booted(lxc_name):
    '''Wait until the container has sufficiently booted to interact with it

    Do this by checking that the runlevel is someting numeric, i. e. not
    "unknown" or "S".
    '''
    timeout = 60
    while timeout > 0:
        timeout -= 1
        time.sleep(1)
        (rc, out, _) = VirtSubproc.execute_timeout(
            None, 10, sudoify(['lxc-attach', '--name', lxc_name, 'runlevel']),
            stdout=subprocess.PIPE)
        if rc != 0:
            adtlog.debug('wait_booted: lxc-attach failed, retrying...')
            continue
        out = out.strip()
        if out.split()[-1].isdigit():
            return

        adtlog.debug('wait_booted: runlevel "%s", retrying...' % out)

    VirtSubproc.bomb('timed out waiting for container %s to start; '
                     'last runlevel "%s"' % (lxc_name, out))


def determine_normal_user(lxc_name):
    '''Check for a normal user to run tests as.'''

    global capabilities, normal_user

    # get the first UID >= 500
    cmd = ['lxc-attach', '--name', lxc_name, '--', 'sh', '-c',
           'getent passwd | sort -t: -nk3 | '
           "awk -F: '{if ($3 >= 500) { print $1; exit } }'"]
    out = VirtSubproc.execute_timeout(None, 10, sudoify(cmd),
                                      stdout=subprocess.PIPE)[1].strip()
    if out:
        normal_user = out
        capabilities.append('suggested-normal-user=' + normal_user)
        adtlog.debug('determine_normal_user: got user "%s"' % normal_user)
    else:
        adtlog.debug('determine_normal_user: no uid >= 500 available')


def hook_open():
    global args, lxc_container_name, shared_dir

    lxc_container_name = get_available_lxc_container_name()
    adtlog.debug('using container name %s' % lxc_container_name)
    if shared_dir is None:
        shared_dir = tempfile.mkdtemp(prefix='adt-virt-lxc.shared.')
    else:
        # don't change the name between resets, to provide stable downtmp paths
        os.makedirs(shared_dir)
    os.chmod(shared_dir, 0o755)
    if args.ephemeral:
        VirtSubproc.check_exec(sudoify(
            ['lxc-start-ephemeral', '--name', lxc_container_name,
             '--keep-data', '--daemon', '--bdir', shared_dir,
             '--orig', args.template]), outp=True)
        # work around https://launchpad.net/bugs/1367730
        VirtSubproc.check_exec(sudoify([
            'lxc-attach', '--name', lxc_container_name, '--', 'chmod', 'go+rx', '/']),
            timeout=30)
    else:
        VirtSubproc.check_exec(sudoify(
            ['lxc-clone', '--new', lxc_container_name, '--orig', args.template]), outp=True)
        VirtSubproc.check_exec(sudoify(
            ['lxc-start', '--name', lxc_container_name, '--daemon',
             '--define', 'lxc.mount.entry=%s %s none bind,create=dir 0 0' % (shared_dir, shared_dir[1:])]))
    try:
        adtlog.debug('waiting for lxc guest start')
        wait_booted(lxc_container_name)
        adtlog.debug('lxc guest started')
        determine_normal_user(lxc_container_name)
        # provide a minimal and clean environment in the container
        VirtSubproc.auxverb = [
            'lxc-attach', '--name', lxc_container_name, '--',
            'env', '-i', 'sh', '-ac',
            '[ -r /etc/environment ] && . /etc/environment 2>/dev/null || true; '
            '[ -r /etc/default/locale ] && . /etc/default/locale 2>/dev/null || true; '
            '[ -r /etc/profile ] && . /etc/profile 2>/dev/null || true; '
            'exec "$@"', '--'
        ]
        if args.sudo:
            VirtSubproc.auxverb = ['sudo', '--preserve-env'] + VirtSubproc.auxverb
        if args.eatmydata:
            check_for_eatmydata(lxc_container_name, args.template)
            VirtSubproc.auxverb.extend(['eatmydata', '--'])
    except:
        # Clean up on failure
        VirtSubproc.check_exec(sudoify(['lxc-stop', '--name', lxc_container_name]))
        VirtSubproc.check_exec(sudoify(['lxc-destroy', '--name', lxc_container_name]))
        raise


def hook_downtmp(path):
    global capabilities, shared_dir

    if shared_dir:
        d = os.path.join(shared_dir, 'downtmp')
        # these permissions are ugly, but otherwise we can't clean up files
        # written by the testbed when running as user
        VirtSubproc.check_exec(['mkdir', '-m', '777', d], downp=True)
        capabilities.append('downtmp-host=' + d)
    else:
        d = VirtSubproc.downtmp_mktemp(path)
    return d


def hook_revert():
    hook_cleanup()
    hook_open()


def hook_cleanup():
    global capabilities, shared_dir

    VirtSubproc.downtmp_remove()
    capabilities = [c for c in capabilities if not c.startswith('downtmp-host')]
    if shared_dir:
        shutil.rmtree(shared_dir)

    VirtSubproc.check_exec(sudoify(['lxc-stop', '--name', lxc_container_name]))
    VirtSubproc.check_exec(sudoify(['lxc-destroy', '--name', lxc_container_name]))


def hook_forked_inchild():
    pass


def hook_capabilities():
    return capabilities


parse_args()
VirtSubproc.main()