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1import os, time, socket, shutil, glob, logging, tempfile, re
2import shlex
3import subprocess
4
5from autotest_lib.client.bin.result_tools import runner as result_tools_runner
6from autotest_lib.client.common_lib import error
7from autotest_lib.client.common_lib.cros.network import ping_runner
8from autotest_lib.client.common_lib.global_config import global_config
9from autotest_lib.server import utils, autotest
10from autotest_lib.server.hosts import host_info
11from autotest_lib.server.hosts import remote
12from autotest_lib.server.hosts import rpc_server_tracker
13from autotest_lib.server.hosts import ssh_multiplex
14
15# pylint: disable=C0111
16
17get_value = global_config.get_config_value
18enable_master_ssh = get_value('AUTOSERV', 'enable_master_ssh', type=bool,
19                              default=False)
20
21# Number of seconds to use the cached up status.
22_DEFAULT_UP_STATUS_EXPIRATION_SECONDS = 300
23_DEFAULT_SSH_PORT = 22
24
25# Number of seconds to wait for the host to shut down in wait_down().
26_DEFAULT_WAIT_DOWN_TIME_SECONDS = 120
27
28# Timeout in seconds for a single call of get_boot_id() in wait_down().
29_DEFAULT_MAX_PING_TIMEOUT = 10
30
31class AbstractSSHHost(remote.RemoteHost):
32    """
33    This class represents a generic implementation of most of the
34    framework necessary for controlling a host via ssh. It implements
35    almost all of the abstract Host methods, except for the core
36    Host.run method.
37    """
38    VERSION_PREFIX = ''
39
40    def _initialize(self, hostname, user="root", port=_DEFAULT_SSH_PORT,
41                    password="", is_client_install_supported=True,
42                    afe_host=None, host_info_store=None, connection_pool=None,
43                    *args, **dargs):
44        super(AbstractSSHHost, self)._initialize(hostname=hostname,
45                                                 *args, **dargs)
46        """
47        @param hostname: The hostname of the host.
48        @param user: The username to use when ssh'ing into the host.
49        @param password: The password to use when ssh'ing into the host.
50        @param port: The port to use for ssh.
51        @param is_client_install_supported: Boolean to indicate if we can
52                install autotest on the host.
53        @param afe_host: The host object attained from the AFE (get_hosts).
54        @param host_info_store: Optional host_info.CachingHostInfoStore object
55                to obtain / update host information.
56        @param connection_pool: ssh_multiplex.ConnectionPool instance to share
57                the master ssh connection across control scripts.
58        """
59        # IP address is retrieved only on demand. Otherwise the host
60        # initialization will fail for host is not online.
61        self._ip = None
62        self.user = user
63        self.port = port
64        self.password = password
65        self._is_client_install_supported = is_client_install_supported
66        self._use_rsync = None
67        self.known_hosts_file = tempfile.mkstemp()[1]
68        self._rpc_server_tracker = rpc_server_tracker.RpcServerTracker(self);
69
70        """
71        Master SSH connection background job, socket temp directory and socket
72        control path option. If master-SSH is enabled, these fields will be
73        initialized by start_master_ssh when a new SSH connection is initiated.
74        """
75        self._connection_pool = connection_pool
76        if connection_pool:
77            self._master_ssh = connection_pool.get(hostname, user, port)
78        else:
79            self._master_ssh = ssh_multiplex.MasterSsh(hostname, user, port)
80
81        self._afe_host = afe_host or utils.EmptyAFEHost()
82        self.host_info_store = (host_info_store or
83                                host_info.InMemoryHostInfoStore())
84
85        # The cached status of whether the DUT responded to ping.
86        self._cached_up_status = None
87        # The timestamp when the value of _cached_up_status is set.
88        self._cached_up_status_updated = None
89
90
91    @property
92    def ip(self):
93        """@return IP address of the host.
94        """
95        if not self._ip:
96            self._ip = socket.getaddrinfo(self.hostname, None)[0][4][0]
97        return self._ip
98
99
100    @property
101    def is_client_install_supported(self):
102        """"
103        Returns True if the host supports autotest client installs, False
104        otherwise.
105        """
106        return self._is_client_install_supported
107
108
109    @property
110    def rpc_server_tracker(self):
111        """"
112        @return The RPC server tracker associated with this host.
113        """
114        return self._rpc_server_tracker
115
116
117    @property
118    def is_default_port(self):
119      """Returns True if its port is default SSH port."""
120      return self.port == _DEFAULT_SSH_PORT
121
122    @property
123    def host_port(self):
124        """Returns hostname if port is default. Otherwise, hostname:port.
125        """
126        if self.is_default_port:
127            return self.hostname
128        else:
129            return '%s:%d' % (self.hostname, self.port)
130
131
132    # Though it doesn't use self here, it is not declared as staticmethod
133    # because its subclass may use self to access member variables.
134    def make_ssh_command(self, user="root", port=_DEFAULT_SSH_PORT, opts='',
135                         hosts_file='/dev/null', connect_timeout=30,
136                         alive_interval=300, alive_count_max=3,
137                         connection_attempts=1):
138        ssh_options = " ".join([
139            opts,
140            self.make_ssh_options(
141                hosts_file=hosts_file, connect_timeout=connect_timeout,
142                alive_interval=alive_interval, alive_count_max=alive_count_max,
143                connection_attempts=connection_attempts)])
144        return "/usr/bin/ssh -a -x %s -l %s -p %d" % (ssh_options, user, port)
145
146
147    @staticmethod
148    def make_ssh_options(hosts_file='/dev/null', connect_timeout=30,
149                         alive_interval=300, alive_count_max=3,
150                         connection_attempts=1):
151        """Composes SSH -o options."""
152        assert isinstance(connect_timeout, (int, long))
153        assert connect_timeout > 0 # can't disable the timeout
154
155        options = [("StrictHostKeyChecking", "no"),
156                   ("UserKnownHostsFile", hosts_file),
157                   ("BatchMode", "yes"),
158                   ("ConnectTimeout", str(connect_timeout)),
159                   ("ServerAliveInterval", str(alive_interval)),
160                   ("ServerAliveCountMax", str(alive_count_max)),
161                   ("ConnectionAttempts", str(connection_attempts))]
162        return " ".join("-o %s=%s" % kv for kv in options)
163
164
165    def use_rsync(self):
166        if self._use_rsync is not None:
167            return self._use_rsync
168
169        # Check if rsync is available on the remote host. If it's not,
170        # don't try to use it for any future file transfers.
171        self._use_rsync = self.check_rsync()
172        if not self._use_rsync:
173            logging.warning("rsync not available on remote host %s -- disabled",
174                            self.host_port)
175        return self._use_rsync
176
177
178    def check_rsync(self):
179        """
180        Check if rsync is available on the remote host.
181        """
182        try:
183            self.run("rsync --version", stdout_tee=None, stderr_tee=None)
184        except error.AutoservRunError:
185            return False
186        return True
187
188
189    def _encode_remote_paths(self, paths, escape=True, use_scp=False):
190        """
191        Given a list of file paths, encodes it as a single remote path, in
192        the style used by rsync and scp.
193        escape: add \\ to protect special characters.
194        use_scp: encode for scp if true, rsync if false.
195        """
196        if escape:
197            paths = [utils.scp_remote_escape(path) for path in paths]
198
199        remote = self.hostname
200
201        # rsync and scp require IPv6 brackets, even when there isn't any
202        # trailing port number (ssh doesn't support IPv6 brackets).
203        # In the Python >= 3.3 future, 'import ipaddress' will parse addresses.
204        if re.search(r':.*:', remote):
205            remote = '[%s]' % remote
206
207        if use_scp:
208            return '%s@%s:"%s"' % (self.user, remote, " ".join(paths))
209        else:
210            return '%s@%s:%s' % (
211                    self.user, remote,
212                    " :".join('"%s"' % p for p in paths))
213
214    def _encode_local_paths(self, paths, escape=True):
215        """
216        Given a list of file paths, encodes it as a single local path.
217        escape: add \\ to protect special characters.
218        """
219        if escape:
220            paths = [utils.sh_escape(path) for path in paths]
221
222        return " ".join('"%s"' % p for p in paths)
223
224
225    def rsync_options(self, delete_dest=False, preserve_symlinks=False,
226                      safe_symlinks=False, excludes=None):
227        """Obtains rsync options for the remote."""
228        ssh_cmd = self.make_ssh_command(user=self.user, port=self.port,
229                                        opts=self._master_ssh.ssh_option,
230                                        hosts_file=self.known_hosts_file)
231        if delete_dest:
232            delete_flag = "--delete"
233        else:
234            delete_flag = ""
235        if safe_symlinks:
236            symlink_flag = "-l --safe-links"
237        elif preserve_symlinks:
238            symlink_flag = "-l"
239        else:
240            symlink_flag = "-L"
241        exclude_args = ''
242        if excludes:
243            exclude_args = ' '.join(
244                    ["--exclude '%s'" % exclude for exclude in excludes])
245        return "%s %s --timeout=1800 --rsh='%s' -az --no-o --no-g %s" % (
246            symlink_flag, delete_flag, ssh_cmd, exclude_args)
247
248
249    def _make_rsync_cmd(self, sources, dest, delete_dest,
250                        preserve_symlinks, safe_symlinks, excludes=None):
251        """
252        Given a string of source paths and a destination path, produces the
253        appropriate rsync command for copying them. Remote paths must be
254        pre-encoded.
255        """
256        rsync_options = self.rsync_options(
257            delete_dest=delete_dest, preserve_symlinks=preserve_symlinks,
258            safe_symlinks=safe_symlinks, excludes=excludes)
259        return 'rsync %s %s "%s"' % (rsync_options, sources, dest)
260
261
262    def _make_ssh_cmd(self, cmd):
263        """
264        Create a base ssh command string for the host which can be used
265        to run commands directly on the machine
266        """
267        base_cmd = self.make_ssh_command(user=self.user, port=self.port,
268                                         opts=self._master_ssh.ssh_option,
269                                         hosts_file=self.known_hosts_file)
270
271        return '%s %s "%s"' % (base_cmd, self.hostname, utils.sh_escape(cmd))
272
273    def _make_scp_cmd(self, sources, dest):
274        """
275        Given a string of source paths and a destination path, produces the
276        appropriate scp command for encoding it. Remote paths must be
277        pre-encoded.
278        """
279        command = ("scp -rq %s -o StrictHostKeyChecking=no "
280                   "-o UserKnownHostsFile=%s -P %d %s '%s'")
281        return command % (self._master_ssh.ssh_option, self.known_hosts_file,
282                          self.port, sources, dest)
283
284
285    def _make_rsync_compatible_globs(self, path, is_local):
286        """
287        Given an rsync-style path, returns a list of globbed paths
288        that will hopefully provide equivalent behaviour for scp. Does not
289        support the full range of rsync pattern matching behaviour, only that
290        exposed in the get/send_file interface (trailing slashes).
291
292        The is_local param is flag indicating if the paths should be
293        interpreted as local or remote paths.
294        """
295
296        # non-trailing slash paths should just work
297        if len(path) == 0 or path[-1] != "/":
298            return [path]
299
300        # make a function to test if a pattern matches any files
301        if is_local:
302            def glob_matches_files(path, pattern):
303                return len(glob.glob(path + pattern)) > 0
304        else:
305            def glob_matches_files(path, pattern):
306                result = self.run("ls \"%s\"%s" % (utils.sh_escape(path),
307                                                   pattern),
308                                  stdout_tee=None, ignore_status=True)
309                return result.exit_status == 0
310
311        # take a set of globs that cover all files, and see which are needed
312        patterns = ["*", ".[!.]*"]
313        patterns = [p for p in patterns if glob_matches_files(path, p)]
314
315        # convert them into a set of paths suitable for the commandline
316        if is_local:
317            return ["\"%s\"%s" % (utils.sh_escape(path), pattern)
318                    for pattern in patterns]
319        else:
320            return [utils.scp_remote_escape(path) + pattern
321                    for pattern in patterns]
322
323
324    def _make_rsync_compatible_source(self, source, is_local):
325        """
326        Applies the same logic as _make_rsync_compatible_globs, but
327        applies it to an entire list of sources, producing a new list of
328        sources, properly quoted.
329        """
330        return sum((self._make_rsync_compatible_globs(path, is_local)
331                    for path in source), [])
332
333
334    def _set_umask_perms(self, dest):
335        """
336        Given a destination file/dir (recursively) set the permissions on
337        all the files and directories to the max allowed by running umask.
338        """
339
340        # now this looks strange but I haven't found a way in Python to _just_
341        # get the umask, apparently the only option is to try to set it
342        umask = os.umask(0)
343        os.umask(umask)
344
345        max_privs = 0777 & ~umask
346
347        def set_file_privs(filename):
348            """Sets mode of |filename|.  Assumes |filename| exists."""
349            file_stat = os.stat(filename)
350
351            file_privs = max_privs
352            # if the original file permissions do not have at least one
353            # executable bit then do not set it anywhere
354            if not file_stat.st_mode & 0111:
355                file_privs &= ~0111
356
357            os.chmod(filename, file_privs)
358
359        # try a bottom-up walk so changes on directory permissions won't cut
360        # our access to the files/directories inside it
361        for root, dirs, files in os.walk(dest, topdown=False):
362            # when setting the privileges we emulate the chmod "X" behaviour
363            # that sets to execute only if it is a directory or any of the
364            # owner/group/other already has execute right
365            for dirname in dirs:
366                os.chmod(os.path.join(root, dirname), max_privs)
367
368            # Filter out broken symlinks as we go.
369            for filename in filter(os.path.exists, files):
370                set_file_privs(os.path.join(root, filename))
371
372
373        # now set privs for the dest itself
374        if os.path.isdir(dest):
375            os.chmod(dest, max_privs)
376        else:
377            set_file_privs(dest)
378
379
380    def get_file(self, source, dest, delete_dest=False, preserve_perm=True,
381                 preserve_symlinks=False, retry=True, safe_symlinks=False):
382        """
383        Copy files from the remote host to a local path.
384
385        Directories will be copied recursively.
386        If a source component is a directory with a trailing slash,
387        the content of the directory will be copied, otherwise, the
388        directory itself and its content will be copied. This
389        behavior is similar to that of the program 'rsync'.
390
391        Args:
392                source: either
393                        1) a single file or directory, as a string
394                        2) a list of one or more (possibly mixed)
395                                files or directories
396                dest: a file or a directory (if source contains a
397                        directory or more than one element, you must
398                        supply a directory dest)
399                delete_dest: if this is true, the command will also clear
400                             out any old files at dest that are not in the
401                             source
402                preserve_perm: tells get_file() to try to preserve the sources
403                               permissions on files and dirs
404                preserve_symlinks: try to preserve symlinks instead of
405                                   transforming them into files/dirs on copy
406                safe_symlinks: same as preserve_symlinks, but discard links
407                               that may point outside the copied tree
408        Raises:
409                AutoservRunError: the scp command failed
410        """
411        logging.debug('get_file. source: %s, dest: %s, delete_dest: %s,'
412                      'preserve_perm: %s, preserve_symlinks:%s', source, dest,
413                      delete_dest, preserve_perm, preserve_symlinks)
414
415        # Start a master SSH connection if necessary.
416        self.start_master_ssh()
417
418        if isinstance(source, basestring):
419            source = [source]
420        dest = os.path.abspath(dest)
421
422        # If rsync is disabled or fails, try scp.
423        try_scp = True
424        if self.use_rsync():
425            logging.debug('Using Rsync.')
426            try:
427                remote_source = self._encode_remote_paths(source)
428                local_dest = utils.sh_escape(dest)
429                rsync = self._make_rsync_cmd(remote_source, local_dest,
430                                             delete_dest, preserve_symlinks,
431                                             safe_symlinks)
432                utils.run(rsync)
433                try_scp = False
434            except error.CmdError, e:
435                # retry on rsync exit values which may be caused by transient
436                # network problems:
437                #
438                # rc 10: Error in socket I/O
439                # rc 12: Error in rsync protocol data stream
440                # rc 23: Partial transfer due to error
441                # rc 255: Ssh error
442                #
443                # Note that rc 23 includes dangling symlinks.  In this case
444                # retrying is useless, but not very damaging since rsync checks
445                # for those before starting the transfer (scp does not).
446                status = e.result_obj.exit_status
447                if status in [10, 12, 23, 255] and retry:
448                    logging.warning('rsync status %d, retrying', status)
449                    self.get_file(source, dest, delete_dest, preserve_perm,
450                                  preserve_symlinks, retry=False)
451                    # The nested get_file() does all that's needed.
452                    return
453                else:
454                    logging.warning("trying scp, rsync failed: %s (%d)",
455                                     e, status)
456
457        if try_scp:
458            logging.debug('Trying scp.')
459            # scp has no equivalent to --delete, just drop the entire dest dir
460            if delete_dest and os.path.isdir(dest):
461                shutil.rmtree(dest)
462                os.mkdir(dest)
463
464            remote_source = self._make_rsync_compatible_source(source, False)
465            if remote_source:
466                # _make_rsync_compatible_source() already did the escaping
467                remote_source = self._encode_remote_paths(
468                        remote_source, escape=False, use_scp=True)
469                local_dest = utils.sh_escape(dest)
470                scp = self._make_scp_cmd(remote_source, local_dest)
471                try:
472                    utils.run(scp)
473                except error.CmdError, e:
474                    logging.debug('scp failed: %s', e)
475                    raise error.AutoservRunError(e.args[0], e.args[1])
476
477        if not preserve_perm:
478            # we have no way to tell scp to not try to preserve the
479            # permissions so set them after copy instead.
480            # for rsync we could use "--no-p --chmod=ugo=rwX" but those
481            # options are only in very recent rsync versions
482            self._set_umask_perms(dest)
483
484
485    def send_file(self, source, dest, delete_dest=False,
486                  preserve_symlinks=False, excludes=None):
487        """
488        Copy files from a local path to the remote host.
489
490        Directories will be copied recursively.
491        If a source component is a directory with a trailing slash,
492        the content of the directory will be copied, otherwise, the
493        directory itself and its content will be copied. This
494        behavior is similar to that of the program 'rsync'.
495
496        Args:
497                source: either
498                        1) a single file or directory, as a string
499                        2) a list of one or more (possibly mixed)
500                                files or directories
501                dest: a file or a directory (if source contains a
502                        directory or more than one element, you must
503                        supply a directory dest)
504                delete_dest: if this is true, the command will also clear
505                             out any old files at dest that are not in the
506                             source
507                preserve_symlinks: controls if symlinks on the source will be
508                    copied as such on the destination or transformed into the
509                    referenced file/directory
510                excludes: A list of file pattern that matches files not to be
511                          sent. `send_file` will fail if exclude is set, since
512                          local copy does not support --exclude, e.g., when
513                          using scp to copy file.
514
515        Raises:
516                AutoservRunError: the scp command failed
517        """
518        logging.debug('send_file. source: %s, dest: %s, delete_dest: %s,'
519                      'preserve_symlinks:%s', source, dest,
520                      delete_dest, preserve_symlinks)
521        # Start a master SSH connection if necessary.
522        self.start_master_ssh()
523
524        if isinstance(source, basestring):
525            source = [source]
526
527        local_sources = self._encode_local_paths(source)
528        if not local_sources:
529            raise error.TestError('source |%s| yielded an empty string' % (
530                source))
531        if local_sources.find('\x00') != -1:
532            raise error.TestError('one or more sources include NUL char')
533
534        # If rsync is disabled or fails, try scp.
535        try_scp = True
536        if self.use_rsync():
537            logging.debug('Using Rsync.')
538            remote_dest = self._encode_remote_paths([dest])
539            try:
540                rsync = self._make_rsync_cmd(local_sources, remote_dest,
541                                             delete_dest, preserve_symlinks,
542                                             False, excludes=excludes)
543                utils.run(rsync)
544                try_scp = False
545            except error.CmdError, e:
546                logging.warning("trying scp, rsync failed: %s", e)
547
548        if try_scp:
549            logging.debug('Trying scp.')
550            if excludes:
551                raise error.AutotestHostRunError(
552                        '--exclude is not supported in scp, try to use rsync. '
553                        'excludes: %s' % ','.join(excludes), None)
554            # scp has no equivalent to --delete, just drop the entire dest dir
555            if delete_dest:
556                is_dir = self.run("ls -d %s/" % dest,
557                                  ignore_status=True).exit_status == 0
558                if is_dir:
559                    cmd = "rm -rf %s && mkdir %s"
560                    cmd %= (dest, dest)
561                    self.run(cmd)
562
563            remote_dest = self._encode_remote_paths([dest], use_scp=True)
564            local_sources = self._make_rsync_compatible_source(source, True)
565            if local_sources:
566                sources = self._encode_local_paths(local_sources, escape=False)
567                scp = self._make_scp_cmd(sources, remote_dest)
568                try:
569                    utils.run(scp)
570                except error.CmdError, e:
571                    logging.debug('scp failed: %s', e)
572                    raise error.AutoservRunError(e.args[0], e.args[1])
573            else:
574                logging.debug('skipping scp for empty source list')
575
576
577    def verify_ssh_user_access(self):
578        """Verify ssh access to this host.
579
580        @returns False if ssh_ping fails due to Permissions error, True
581                 otherwise.
582        """
583        try:
584            self.ssh_ping()
585        except (error.AutoservSshPermissionDeniedError,
586                error.AutoservSshPingHostError):
587            return False
588        return True
589
590
591    def ssh_ping(self, timeout=60, connect_timeout=None, base_cmd='true'):
592        """
593        Pings remote host via ssh.
594
595        @param timeout: Time in seconds before giving up.
596                        Defaults to 60 seconds.
597        @param base_cmd: The base command to run with the ssh ping.
598                         Defaults to true.
599        @raise AutoservSSHTimeout: If the ssh ping times out.
600        @raise AutoservSshPermissionDeniedError: If ssh ping fails due to
601                                                 permissions.
602        @raise AutoservSshPingHostError: For other AutoservRunErrors.
603        """
604        ctimeout = min(timeout, connect_timeout or timeout)
605        try:
606            self.run(base_cmd, timeout=timeout, connect_timeout=ctimeout,
607                     ssh_failure_retry_ok=True)
608        except error.AutoservSSHTimeout:
609            msg = "Host (ssh) verify timed out (timeout = %d)" % timeout
610            raise error.AutoservSSHTimeout(msg)
611        except error.AutoservSshPermissionDeniedError:
612            #let AutoservSshPermissionDeniedError be visible to the callers
613            raise
614        except error.AutoservRunError, e:
615            # convert the generic AutoservRunError into something more
616            # specific for this context
617            raise error.AutoservSshPingHostError(e.description + '\n' +
618                                                 repr(e.result_obj))
619
620
621    def is_up(self, timeout=60, connect_timeout=None, base_cmd='true'):
622        """
623        Check if the remote host is up by ssh-ing and running a base command.
624
625        @param timeout: timeout in seconds.
626        @param base_cmd: a base command to run with ssh. The default is 'true'.
627        @returns True if the remote host is up before the timeout expires,
628                 False otherwise.
629        """
630        try:
631            self.ssh_ping(timeout=timeout,
632                          connect_timeout=connect_timeout,
633                          base_cmd=base_cmd)
634        except error.AutoservError:
635            return False
636        else:
637            return True
638
639
640    def is_up_fast(self):
641        """Return True if the host can be pinged."""
642        ping_config = ping_runner.PingConfig(
643                self.hostname, count=3, ignore_result=True, ignore_status=True)
644        return ping_runner.PingRunner().ping(ping_config).received > 0
645
646
647    def wait_up(self, timeout=None):
648        """
649        Wait until the remote host is up or the timeout expires.
650
651        In fact, it will wait until an ssh connection to the remote
652        host can be established, and getty is running.
653
654        @param timeout time limit in seconds before returning even
655            if the host is not up.
656
657        @returns True if the host was found to be up before the timeout expires,
658                 False otherwise
659        """
660        if timeout:
661            current_time = int(time.time())
662            end_time = current_time + timeout
663
664        autoserv_error_logged = False
665        while not timeout or current_time < end_time:
666            if self.is_up(timeout=end_time - current_time,
667                          connect_timeout=20):
668                try:
669                    if self.are_wait_up_processes_up():
670                        logging.debug('Host %s is now up', self.host_port)
671                        return True
672                except error.AutoservError as e:
673                    if not autoserv_error_logged:
674                        logging.debug('Ignoring failure to reach %s: %s %s',
675                                      self.host_port, e,
676                                      '(and further similar failures)')
677                        autoserv_error_logged = True
678            time.sleep(1)
679            current_time = int(time.time())
680
681        logging.debug('Host %s is still down after waiting %d seconds',
682                      self.host_port, int(timeout + time.time() - end_time))
683        return False
684
685
686    def wait_down(self, timeout=_DEFAULT_WAIT_DOWN_TIME_SECONDS,
687                  warning_timer=None, old_boot_id=None,
688                  max_ping_timeout=_DEFAULT_MAX_PING_TIMEOUT):
689        """
690        Wait until the remote host is down or the timeout expires.
691
692        If old_boot_id is provided, waits until either the machine is
693        unpingable or self.get_boot_id() returns a value different from
694        old_boot_id. If the boot_id value has changed then the function
695        returns True under the assumption that the machine has shut down
696        and has now already come back up.
697
698        If old_boot_id is None then until the machine becomes unreachable the
699        method assumes the machine has not yet shut down.
700
701        @param timeout Time limit in seconds before returning even if the host
702            is still up.
703        @param warning_timer Time limit in seconds that will generate a warning
704            if the host is not down yet. Can be None for no warning.
705        @param old_boot_id A string containing the result of self.get_boot_id()
706            prior to the host being told to shut down. Can be None if this is
707            not available.
708        @param max_ping_timeout Maximum timeout in seconds for each
709            self.get_boot_id() call. If this timeout is hit, it is assumed that
710            the host went down and became unreachable.
711
712        @returns True if the host was found to be down (max_ping_timeout timeout
713            expired or boot_id changed if provided) and False if timeout
714            expired.
715        """
716        #TODO: there is currently no way to distinguish between knowing
717        #TODO: boot_id was unsupported and not knowing the boot_id.
718        current_time = int(time.time())
719        end_time = current_time + timeout
720
721        if warning_timer:
722            warn_time = current_time + warning_timer
723
724        if old_boot_id is not None:
725            logging.debug('Host %s pre-shutdown boot_id is %s',
726                          self.host_port, old_boot_id)
727
728        # Impose semi real-time deadline constraints, since some clients
729        # (eg: watchdog timer tests) expect strict checking of time elapsed.
730        # Each iteration of this loop is treated as though it atomically
731        # completes within current_time, this is needed because if we used
732        # inline time.time() calls instead then the following could happen:
733        #
734        # while time.time() < end_time:                     [23 < 30]
735        #    some code.                                     [takes 10 secs]
736        #    try:
737        #        new_boot_id = self.get_boot_id(timeout=end_time - time.time())
738        #                                                   [30 - 33]
739        # The last step will lead to a return True, when in fact the machine
740        # went down at 32 seconds (>30). Hence we need to pass get_boot_id
741        # the same time that allowed us into that iteration of the loop.
742        while current_time < end_time:
743            ping_timeout = min(end_time - current_time, max_ping_timeout)
744            try:
745                new_boot_id = self.get_boot_id(timeout=ping_timeout)
746            except error.AutoservError:
747                logging.debug('Host %s is now unreachable over ssh, is down',
748                              self.host_port)
749                return True
750            else:
751                # if the machine is up but the boot_id value has changed from
752                # old boot id, then we can assume the machine has gone down
753                # and then already come back up
754                if old_boot_id is not None and old_boot_id != new_boot_id:
755                    logging.debug('Host %s now has boot_id %s and so must '
756                                  'have rebooted', self.host_port, new_boot_id)
757                    return True
758
759            if warning_timer and current_time > warn_time:
760                self.record("INFO", None, "shutdown",
761                            "Shutdown took longer than %ds" % warning_timer)
762                # Print the warning only once.
763                warning_timer = None
764                # If a machine is stuck switching runlevels
765                # This may cause the machine to reboot.
766                self.run('kill -HUP 1', ignore_status=True)
767
768            time.sleep(1)
769            current_time = int(time.time())
770
771        return False
772
773
774    # tunable constants for the verify & repair code
775    AUTOTEST_GB_DISKSPACE_REQUIRED = get_value("SERVER",
776                                               "gb_diskspace_required",
777                                               type=float,
778                                               default=20.0)
779
780
781    def verify_connectivity(self):
782        super(AbstractSSHHost, self).verify_connectivity()
783
784        logging.info('Pinging host ' + self.host_port)
785        self.ssh_ping()
786        logging.info("Host (ssh) %s is alive", self.host_port)
787
788        if self.is_shutting_down():
789            raise error.AutoservHostIsShuttingDownError("Host is shutting down")
790
791
792    def verify_software(self):
793        super(AbstractSSHHost, self).verify_software()
794        try:
795            self.check_diskspace(autotest.Autotest.get_install_dir(self),
796                                 self.AUTOTEST_GB_DISKSPACE_REQUIRED)
797        except error.AutoservDiskFullHostError:
798            # only want to raise if it's a space issue
799            raise
800        except (error.AutoservHostError, autotest.AutodirNotFoundError):
801            logging.exception('autodir space check exception, this is probably '
802                             'safe to ignore\n')
803
804
805    def close(self):
806        super(AbstractSSHHost, self).close()
807        self.rpc_server_tracker.disconnect_all()
808        if not self._connection_pool:
809            self._master_ssh.close()
810        if os.path.exists(self.known_hosts_file):
811            os.remove(self.known_hosts_file)
812
813
814    def restart_master_ssh(self):
815        """
816        Stop and restart the ssh master connection.  This is meant as a last
817        resort when ssh commands fail and we don't understand why.
818        """
819        logging.debug('Restarting master ssh connection')
820        self._master_ssh.close()
821        self._master_ssh.maybe_start(timeout=30)
822
823
824
825    def start_master_ssh(self, timeout=5):
826        """
827        Called whenever a slave SSH connection needs to be initiated (e.g., by
828        run, rsync, scp). If master SSH support is enabled and a master SSH
829        connection is not active already, start a new one in the background.
830        Also, cleanup any zombie master SSH connections (e.g., dead due to
831        reboot).
832
833        timeout: timeout in seconds (default 5) to wait for master ssh
834                 connection to be established. If timeout is reached, a
835                 warning message is logged, but no other action is taken.
836        """
837        if not enable_master_ssh:
838            return
839        self._master_ssh.maybe_start(timeout=timeout)
840
841
842    def clear_known_hosts(self):
843        """Clears out the temporary ssh known_hosts file.
844
845        This is useful if the test SSHes to the machine, then reinstalls it,
846        then SSHes to it again.  It can be called after the reinstall to
847        reduce the spam in the logs.
848        """
849        logging.info("Clearing known hosts for host '%s', file '%s'.",
850                     self.host_port, self.known_hosts_file)
851        # Clear out the file by opening it for writing and then closing.
852        fh = open(self.known_hosts_file, "w")
853        fh.close()
854
855
856    def collect_logs(self, remote_src_dir, local_dest_dir, ignore_errors=True):
857        """Copy log directories from a host to a local directory.
858
859        @param remote_src_dir: A destination directory on the host.
860        @param local_dest_dir: A path to a local destination directory.
861            If it doesn't exist it will be created.
862        @param ignore_errors: If True, ignore exceptions.
863
864        @raises OSError: If there were problems creating the local_dest_dir and
865            ignore_errors is False.
866        @raises AutoservRunError, AutotestRunError: If something goes wrong
867            while copying the directories and ignore_errors is False.
868        """
869        if not self.check_cached_up_status():
870            logging.warning('Host %s did not answer to ping, skip collecting '
871                            'logs.', self.host_port)
872            return
873
874        locally_created_dest = False
875        if (not os.path.exists(local_dest_dir)
876                or not os.path.isdir(local_dest_dir)):
877            try:
878                os.makedirs(local_dest_dir)
879                locally_created_dest = True
880            except OSError as e:
881                logging.warning('Unable to collect logs from host '
882                                '%s: %s', self.host_port, e)
883                if not ignore_errors:
884                    raise
885                return
886
887        # Build test result directory summary
888        try:
889            result_tools_runner.run_on_client(self, remote_src_dir)
890        except (error.AutotestRunError, error.AutoservRunError,
891                error.AutoservSSHTimeout) as e:
892            logging.exception(
893                    'Non-critical failure: Failed to collect and throttle '
894                    'results at %s from host %s', remote_src_dir,
895                    self.host_port)
896
897        try:
898            self.get_file(remote_src_dir, local_dest_dir, safe_symlinks=True)
899        except (error.AutotestRunError, error.AutoservRunError,
900                error.AutoservSSHTimeout) as e:
901            logging.warning('Collection of %s to local dir %s from host %s '
902                            'failed: %s', remote_src_dir, local_dest_dir,
903                            self.host_port, e)
904            if locally_created_dest:
905                shutil.rmtree(local_dest_dir, ignore_errors=ignore_errors)
906            if not ignore_errors:
907                raise
908
909        # Clean up directory summary file on the client side.
910        try:
911            result_tools_runner.run_on_client(self, remote_src_dir,
912                                              cleanup_only=True)
913        except (error.AutotestRunError, error.AutoservRunError,
914                error.AutoservSSHTimeout) as e:
915            logging.exception(
916                    'Non-critical failure: Failed to cleanup result summary '
917                    'files at %s in host %s', remote_src_dir, self.hostname)
918
919
920    def create_ssh_tunnel(self, port, local_port):
921        """Create an ssh tunnel from local_port to port.
922
923        This is used to forward a port securely through a tunnel process from
924        the server to the DUT for RPC server connection.
925
926        @param port: remote port on the host.
927        @param local_port: local forwarding port.
928
929        @return: the tunnel process.
930        """
931        tunnel_options = '-n -N -q -L %d:localhost:%d' % (local_port, port)
932        ssh_cmd = self.make_ssh_command(opts=tunnel_options, port=self.port)
933        tunnel_cmd = '%s %s' % (ssh_cmd, self.hostname)
934        logging.debug('Full tunnel command: %s', tunnel_cmd)
935        # Exec the ssh process directly here rather than using a shell.
936        # Using a shell leaves a dangling ssh process, because we deliver
937        # signals to the shell wrapping ssh, not the ssh process itself.
938        args = shlex.split(tunnel_cmd)
939        tunnel_proc = subprocess.Popen(args, close_fds=True)
940        logging.debug('Started ssh tunnel, local = %d'
941                      ' remote = %d, pid = %d',
942                      local_port, port, tunnel_proc.pid)
943        return tunnel_proc
944
945
946    def disconnect_ssh_tunnel(self, tunnel_proc, port):
947        """
948        Disconnects a previously forwarded port from the server to the DUT for
949        RPC server connection.
950
951        @param tunnel_proc: a tunnel process returned from |create_ssh_tunnel|.
952        @param port: remote port on the DUT, used in ADBHost.
953
954        """
955        if tunnel_proc.poll() is None:
956            tunnel_proc.terminate()
957            logging.debug('Terminated tunnel, pid %d', tunnel_proc.pid)
958        else:
959            logging.debug('Tunnel pid %d terminated early, status %d',
960                          tunnel_proc.pid, tunnel_proc.returncode)
961
962
963    def get_os_type(self):
964        """Returns the host OS descriptor (to be implemented in subclasses).
965
966        @return A string describing the OS type.
967        """
968        raise NotImplementedError
969
970
971    def check_cached_up_status(
972            self, expiration_seconds=_DEFAULT_UP_STATUS_EXPIRATION_SECONDS):
973        """Check if the DUT responded to ping in the past `expiration_seconds`.
974
975        @param expiration_seconds: The number of seconds to keep the cached
976                status of whether the DUT responded to ping.
977        @return: True if the DUT has responded to ping during the past
978                 `expiration_seconds`.
979        """
980        # Refresh the up status if any of following conditions is true:
981        # * cached status is never set
982        # * cached status is False, so the method can check if the host is up
983        #   again.
984        # * If the cached status is older than `expiration_seconds`
985        expire_time = time.time() - expiration_seconds
986        if (self._cached_up_status_updated is None or
987                not self._cached_up_status or
988                self._cached_up_status_updated < expire_time):
989            self._cached_up_status = self.is_up_fast()
990            self._cached_up_status_updated = time.time()
991        return self._cached_up_status
992