#!/usr/pkg/bin/python3.13
#
# autopkgtest-virt-ssh is part of autopkgtest
# autopkgtest is a tool for testing Debian binary packages
#
# autopkgtest is Copyright (C) 2006-2015 Canonical Ltd.
#
# Authors:
#    Jean-Baptiste Lallement <jean-baptiste.lallement@canonical.com>
#    Martin Pitt <martin.pitt@ubuntu.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 argparse
import tempfile
import shutil
import shlex
import time
import subprocess
import socket

sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__)))))
sys.path.insert(0, os.path.join(os.path.dirname(os.path.dirname(
    os.path.abspath(__file__))), 'lib'))

from reprotest.lib import VirtSubproc
from reprotest.lib import adtlog

capabilities = []
args = None
workdir = None
sshcmd = None
sshconfig = {'identity': None,
             'login': None,
             'password': None,
             'port': None,
             'options': None,
             'hostname': None,
             'capabilities': None,
             'extraopts': None}
# Note: Running in jenkins might require -tt
sshopts = '-q -o BatchMode=yes -o UserKnownHostsFile=/dev/null '\
          '-o StrictHostKeyChecking=no -o CheckHostIP=no '\
          '-o ControlMaster=auto -o ControlPersist=60 '\
          '-o ControlPath=%s/ssh_control-%%r@%%h:%%p'


# Tests or builds sometimes leak background processes which might still be
# connected to ssh's stdout/err; we need to kill these after the main program
# (build or test script) finishes, otherwise we get eternal hangs as ssh waits
# until nothing is connected to its tty any more. So we run this in ssh,
# wrapping the actual command.
# We also want to avoid exiting with 255 as that's ssh's exit code if something
# with the connection failed; so we translate that to 253.
terminal_kill_wrapper = '''#!/bin/bash
set -u
PPPID=$(cut -f4 -d' ' /proc/$PPID/stat)
%s
"$@"; RC=$?
set -e
myout=$(readlink /proc/$$/fd/1)
myerr=$(readlink /proc/$$/fd/2)
myout="${myout/[/\\\\[}"; myout="${myout/]/\\\\]}"
myerr="${myerr/[/\\\\[}"; myerr="${myerr/]/\\\\]}"

# determine processes which have myout or myerr open
PS=$(ls -l /proc/[0-9]*/fd/* 2>/dev/null | sed -nr '\#('"$myout"'|'"$myerr"')# { s#^.*/proc/([0-9]+)/.*$#\\1#; p}'|sort -u)

KILL=""
for pid in $PS; do
    [ $pid -ne $$ ] && [ $pid -ne $PPID ] && [ $pid -ne $PPPID ] || continue
    [ -r /proc/$pid/comm ] && [ "$(< /proc/$pid/comm)" != sshd ] || continue
    #echo "XXXautopkgtest-ssh-wrapper($$ $PPID $PPPID $myout $myerr): killing $pid (`cat /proc/$pid/cmdline`)" >&2
    KILL="$KILL $pid"
done

[ -z "$KILL" ] || kill -9 $KILL || true
[ $RC != 255 ] || RC=253
exit $RC
'''


cleanup_paths = []  # paths on the device which we created


def parse_args():
    global args, capabilities

    parser = argparse.ArgumentParser()

    parser.add_argument('-d', '--debug', action='store_true',
                        help='Enable debugging output')
    parser.add_argument('-H', '--hostname',
                        help='hostname with optional user: [user@]hostname')
    parser.add_argument('-i', '--identity',
                        help='Selects a file from which the identity '
                        '(private key) for public key authentication is '
                        'read')
    parser.add_argument('-l', '--login',
                        help='Specifies the user to log in as on the '
                        'remote machine.')
    parser.add_argument('-P', '--password',
                        help='Specifies the sudo password on the remote host.'
                        ' It can be the password in clear text or a file '
                        'containing the password.')
    parser.add_argument('-p', '--port', type=str,
                        help='ssh port to use to connect to the host')
    parser.add_argument('-o', '--options',
                        help='Passed verbatim to ssh; see man ssh_config')
    parser.add_argument('-r', '--reboot', action='store_true',
                        help='Indicate that testbed supports reboot')
    parser.add_argument('--capability', action='append',
                        help='Indicate that testbed supports given capability.'
                        ' Can be specified multiple times. Never use this on '
                        'precious testbeds!')
    parser.add_argument('-s', '--setup-script',
                        help='Setup script to prepare testbed and ssh connection')
    parser.add_argument('--timeout-ssh', metavar='SECS', type=int, default=300,
                        help='Timeout for waiting for the ssh connection, in '
                        'seconds (default: %(default)s)')
    parser.add_argument('scriptargs', nargs=argparse.REMAINDER,
                        help='Additional arguments to pass to the setup '
                        'script for configuration')

    args = parser.parse_args()
    if args.debug:
        adtlog.verbosity = 2
    adtlog.debug(str(args))

    # shortcut for shipped scripts
    if args.setup_script and not os.path.exists(args.setup_script):
        shipped_script = os.path.join('/usr/share/autopkgtest/ssh-setup',
                                      args.setup_script)
        if os.path.exists(shipped_script):
            args.setup_script = shipped_script

    # turn --password file path into the actual password
    if args.password and os.path.exists(args.password):
        with open(args.password) as f:
            args.password = f.read().strip()

    if args.reboot:
        capabilities.append('reboot')

    if args.capability:
        capabilities += args.capability


def execute_setup_script(command, fail_ok=False, print_stderr=True):
    '''Run the --setup-script, if given.

    Arguments passed after -- to the main program are passed verbatim to the
    setup script.  The output of the script must be of the form key=value and
    is parsed to populate sshconfig. Command line options always override the
    values from the setup script.

    :param command: Command to execute. The command must match a function in
                    the ssh script
    :param fail_ok: If True, failures will not cause bombing
    :return: A tuple (return code, stdout, stderr). stdout and stderr may be
             None, for example if the script fails and fail_ok is True.
    '''
    global sshconfig, args
    out = None
    err = None

    if args.setup_script:
        fpath = args.setup_script
        if not os.path.isfile(fpath):
            VirtSubproc.bomb('File not found: %s' % fpath)
        elif not os.access(fpath, os.X_OK):
            VirtSubproc.bomb('File is not executable: %s' % fpath)

        if args.scriptargs and args.scriptargs[0] == '--':
            del args.scriptargs[0]
        cmd = [args.setup_script, command] + args.scriptargs
        if args.login:
            cmd += ['-l', args.login]
        if sshconfig.get('extraopts'):
            cmd += sshconfig['extraopts'].split(' ')

        adtlog.debug('Executing setup script: %s' % ' '.join(cmd))
        (status, out, err) = VirtSubproc.execute_timeout(
            None,
            1800,
            cmd,
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE)
        if print_stderr:
            # Keep outputting the error on stderr as well as capturing it
            sys.stderr.write(err)
        if status != 0:
            err = 'setup script failed with code %i: %s' % (status,
                                                            ' '.join(cmd))
            if fail_ok:
                adtlog.debug(err)
                return (status, out, err)
            else:
                execute_setup_script('debug-failure', fail_ok=True)
                VirtSubproc.bomb(err)

        if command in ['open', 'revert']:
            for k, v in dict([s.split('=', 1) for s in out.splitlines()
                              if s and '=' in s]).items():
                sshconfig[k] = v
            adtlog.debug('got sshconfig from script %s: %s' % (command, sshconfig))

    # Command line arguments take priority
    for param in sshconfig:
        a = getattr(args, param, None)
        if a is not None:
            sshconfig[param] = a

    return (0, out, err)


def host_setup(command):
    '''Prepare remote host for ssh connection and return its configuration

    When a --setup-script is passed, execute it and return its configuration.
    The configuration of the remote side can be overloaded by options on the
    command line.

    command should either be "open" or "revert".

    Sets the global sshcmd accordingly.
    '''
    global workdir, sshcmd

    try:
        if workdir is None:
            workdir = tempfile.mkdtemp(prefix='autopkgtest-virt-ssh.')
            os.chmod(workdir, 0o755)
        execute_setup_script(command)
        build_sshcmd()
        wait_for_ssh(sshcmd, timeout=args.timeout_ssh)
        build_auxverb()
    except:
        # Clean up on failure
        hook_cleanup()
        raise
    adtlog.debug('host set up for %s; ssh command: %s' % (command, sshcmd))


def build_sshcmd():
    '''Generate sshcmd from sshconfig'''

    global sshconfig, sshcmd, capabilities, workdir

    sshcmd = ['ssh'] + (sshopts % workdir).split()
    for param in sshconfig:
        if not sshconfig[param]:
            continue

        if param == 'identity':
            sshcmd += ['-i', sshconfig[param]]
        elif param == 'login':
            sshcmd += ['-l', sshconfig[param]]
            if sshconfig[param] != 'root':
                capabilities.append('suggested-normal-user=' + sshconfig[param])
        elif param == 'port':
            sshcmd += ['-p', sshconfig[param]]
        elif param == 'options':
            sshcmd += sshconfig[param].split()
        elif param == 'hostname':
            sshcmd += [sshconfig[param]]
        elif param == 'capabilities':
            capabilities += sshconfig[param].replace(',', ' ').split()
            # Remove duplicates
            capabilities = list(set(capabilities))
        elif param == 'password':
            if not args.password:
                args.password = sshconfig[param]  # forward to can_sudo
        elif param == 'extraopts':
            # Do nothing but don't print a warning. It will be passed back as
            # is to the ssh setup script
            pass
        else:
            adtlog.warning('Ignoring invalid parameter: %s' % param)


def wait_for_ssh(ssh_cmd, timeout=300):
    '''Wait until testbed responds to ssh'''

    cmd = ssh_cmd + ['/bin/true']
    start = time.time()
    elapsed = 0
    delay = 3

    while elapsed < timeout:
        try:
            rc = VirtSubproc.execute_timeout(None, 30, cmd)[0]
            if rc == 0:
                adtlog.debug('ssh connection established.')
                break
        except VirtSubproc.Timeout:
            pass
        adtlog.warning('ssh connection failed. Retrying in %d seconds...'
                       % delay)
        time.sleep(delay)
        elapsed = time.time() - start
    else:
        execute_setup_script('debug-failure', fail_ok=True)
        VirtSubproc.bomb('Timed out on waiting for ssh connection')


def build_auxverb():
    '''Generate auxverb from sshconfig'''

    global sshconfig, sshcmd, capabilities, workdir

    if sshconfig['login'] != 'root':
        (sudocmd, askpass) = can_sudo(sshcmd)
    else:
        (sudocmd, askpass) = (None, None)
    if sudocmd:
        if 'root-on-testbed' not in capabilities:
            capabilities.append('root-on-testbed')
    else:
        if 'root-on-testbed' in capabilities:
            capabilities.remove('root-on-testbed')

    extra_cmd = ''
    if askpass:
        extra_cmd += 'export SUDO_ASKPASS=%s\n' % askpass

    # create remote wrapper
    rc = VirtSubproc.execute_timeout(
        terminal_kill_wrapper % extra_cmd, 30, sshcmd +
        ['rm -f /tmp/autopkgtest-run-wrapper; set -C; cat > /tmp/autopkgtest-run-wrapper; chmod 755 /tmp/autopkgtest-run-wrapper'],
        stdin=subprocess.PIPE)[0]
    if rc != 0:
        VirtSubproc.bomb('Failed to create /tmp/autopkgtest-run-wrapper')

    # create local auxverb script
    auxverb = os.path.join(workdir, 'runcmd')
    with open(auxverb, 'w') as f:
        f.write('''#!/bin/bash
exec %s -- %s /tmp/autopkgtest-run-wrapper $(printf '%%q ' "${@%% }")
''' % (" ".join(sshcmd), sudocmd or ''))
    os.chmod(auxverb, 0o755)
    VirtSubproc.auxverb = [auxverb]


def can_sudo(ssh_cmd):
    '''Determine if the user can sudo

    :param ssh_cmd: ssh command to connect to the host
    :returns: (sudo_command, askpass_path); (None, None) if user cannot sudo
    '''
    global cleanup_paths

    sudocmd = None

    # if we have a password, use that
    if args.password:
        cmd = 'F=`mktemp --tmpdir sudo_askpass.XXXX`;' \
              '/bin/echo -e "#!/bin/sh\necho \'%s\'" > $F;' \
              'chmod u+x $F; sync; echo $F' % args.password
        askpass = VirtSubproc.check_exec(
            ssh_cmd + ['/bin/sh', '-ec', shlex.quote(cmd)],
            outp=True, timeout=30).strip()
        adtlog.debug('created SUDO_ASKPASS from specified password')
        cleanup_paths.append(askpass)

        sudocmd = 'SUDO_ASKPASS=%s sudo -A' % askpass
        cmd = ssh_cmd + ['--'] + sudocmd.split() + ['/bin/true']
        (rc, _, err) = VirtSubproc.execute_timeout(None, 30, cmd,
                                                   stderr=subprocess.PIPE)
        if rc == 0:
            if err:
                VirtSubproc.bomb('sudo failed with stderr: "%s"' % err)
            adtlog.debug('can_sudo: askpass works')
            return (sudocmd, askpass)
        else:
            adtlog.warning('specified sudo password fails, no root available')
            pass

    # otherwise, test if we can do it without password (NOPASSWD sudo option)
    sudocmd = "sudo -n"
    cmd = ssh_cmd + ['--'] + sudocmd.split() + ['/bin/true']
    (rc, _, err) = VirtSubproc.execute_timeout(None, 30, cmd,
                                               stderr=subprocess.PIPE)
    if rc == 0:
        if err:
            VirtSubproc.bomb('sudo failed with stderr: "%s"' % err)
        adtlog.debug('can_sudo: sudo without password works')
        return (sudocmd, None)
    else:
        adtlog.debug('can_sudo: sudo without password does not work')

    return (None, None)


def hook_debug_fail():
    # Don't print stderr; if we're being called for the hook, we assume the
    # caller is going to do that.
    (status, out, err) = execute_setup_script('debug-failure',
                                              fail_ok=True,
                                              print_stderr=False)
    return err


def hook_open():
    host_setup('open')


def hook_downtmp(path):
    return VirtSubproc.downtmp_mktemp(path)


def hook_revert():
    host_setup('revert')


def wait_port_down(host, port, timeout):
    '''Wait until host:port stops responding'''

    VirtSubproc.timeout_start(timeout)
    while True:
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        try:
            res = s.connect_ex((host, port))
            adtlog.debug('wait_port_down() connect: %s' % os.strerror(res))
            if res != 0:
                break
            # connect might succeed with port forwarding (e. g. QEMU)
            try:
                r = s.recv(1, socket.MSG_WAITALL)
                adtlog.debug('wait_port_down() recv: "%s"' % str(r))
                if not r:
                    break
            except OSError:
                break
            time.sleep(0.1)
        finally:
            s.close()
    VirtSubproc.timeout_stop()


def hook_wait_reboot():
    global sshcmd

    if args.setup_script:
        (rc, _, _) = execute_setup_script('wait-reboot', fail_ok=True)
    else:
        # if we don't have a setup script, use the fallback below
        rc = 1

    if rc != 0:
        adtlog.debug('setup script wait-reboot failed, waiting for ssh to go down...')
        VirtSubproc.execute_timeout(None, 10, sshcmd + ['-O', 'exit'])
        # wait for ssh/the machine to go down; we can't just call ssh sleep
        # for this, this often hangs when sshd is being shut down
        if sshconfig['port'] is not None:
            port = int(sshconfig['port'])
        else:
            port = 22
        try:
            wait_port_down(sshconfig['hostname'], port, 300)
        except VirtSubproc.Timeout:
            execute_setup_script('debug-failure', fail_ok=True)
            VirtSubproc.bomb('timed out waiting for testbed to reboot')

    build_sshcmd()
    wait_for_ssh(sshcmd, timeout=args.timeout_ssh)
    build_auxverb()


def hook_cleanup():
    global capabilities, workdir, cleanup_paths, sshcmd

    try:
        VirtSubproc.downtmp_remove()
        if cleanup_paths:
            VirtSubproc.check_exec(['rm', '-rf'] + cleanup_paths, downp=True,
                                   timeout=VirtSubproc.copy_timeout)
    except VirtSubproc.Timeout:
        adtlog.error('Removing temporary files on testbed timed out')
        # still do the remaining cleanup

    execute_setup_script('cleanup')

    capabilities = [c for c in capabilities if not c.startswith('downtmp-host')]

    # terminate ssh connection muxer; it inherits our stderr (which causes an
    # eternal hang of tee processes), and we are going to remove the socket dir
    # anyway
    if sshcmd:
        VirtSubproc.execute_timeout(None, 10, sshcmd + ['-O', 'exit'])

    if workdir:
        shutil.rmtree(workdir, ignore_errors=True)
        workdir = None


def hook_capabilities():
    return capabilities


parse_args()
VirtSubproc.main()
