| #!/usr/bin/python |
| # Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| |
| # Virtual Me2Me implementation. This script runs and manages the processes |
| # required for a Virtual Me2Me desktop, which are: X server, X desktop |
| # session, and Host process. |
| # This script is intended to run continuously as a background daemon |
| # process, running under an ordinary (non-root) user account. |
| |
| import atexit |
| import errno |
| import fcntl |
| import getpass |
| import grp |
| import hashlib |
| import json |
| import logging |
| import optparse |
| import os |
| import pipes |
| import platform |
| import psutil |
| import platform |
| import signal |
| import socket |
| import subprocess |
| import sys |
| import tempfile |
| import time |
| import uuid |
| |
| LOG_FILE_ENV_VAR = "CHROME_REMOTE_DESKTOP_LOG_FILE" |
| |
| # This script has a sensible default for the initial and maximum desktop size, |
| # which can be overridden either on the command-line, or via a comma-separated |
| # list of sizes in this environment variable. |
| DEFAULT_SIZES_ENV_VAR = "CHROME_REMOTE_DESKTOP_DEFAULT_DESKTOP_SIZES" |
| |
| # By default, provide a maximum size that is large enough to support clients |
| # with large or multiple monitors. This is a comma-separated list of |
| # resolutions that will be made available if the X server supports RANDR. These |
| # defaults can be overridden in ~/.profile. |
| DEFAULT_SIZES = "1600x1200,3840x2560" |
| |
| # If RANDR is not available, use a smaller default size. Only a single |
| # resolution is supported in this case. |
| DEFAULT_SIZE_NO_RANDR = "1600x1200" |
| |
| SCRIPT_PATH = sys.path[0] |
| |
| IS_INSTALLED = (os.path.basename(sys.argv[0]) != 'linux_me2me_host.py') |
| |
| if IS_INSTALLED: |
| HOST_BINARY_NAME = "chrome-remote-desktop-host" |
| else: |
| HOST_BINARY_NAME = "remoting_me2me_host" |
| |
| CHROME_REMOTING_GROUP_NAME = "chrome-remote-desktop" |
| |
| HOME_DIR = os.environ["HOME"] |
| CONFIG_DIR = os.path.join(HOME_DIR, ".config/chrome-remote-desktop") |
| SESSION_FILE_PATH = os.path.join(HOME_DIR, ".chrome-remote-desktop-session") |
| SYSTEM_SESSION_FILE_PATH = "/etc/chrome-remote-desktop-session" |
| |
| X_LOCK_FILE_TEMPLATE = "/tmp/.X%d-lock" |
| FIRST_X_DISPLAY_NUMBER = 20 |
| |
| # Amount of time to wait between relaunching processes. |
| SHORT_BACKOFF_TIME = 5 |
| LONG_BACKOFF_TIME = 60 |
| |
| # How long a process must run in order not to be counted against the restart |
| # thresholds. |
| MINIMUM_PROCESS_LIFETIME = 60 |
| |
| # Thresholds for switching from fast- to slow-restart and for giving up |
| # trying to restart entirely. |
| SHORT_BACKOFF_THRESHOLD = 5 |
| MAX_LAUNCH_FAILURES = SHORT_BACKOFF_THRESHOLD + 10 |
| |
| # Globals needed by the atexit cleanup() handler. |
| g_desktops = [] |
| g_host_hash = hashlib.md5(socket.gethostname()).hexdigest() |
| |
| |
| def is_supported_platform(): |
| # Always assume that the system is supported if the config directory or |
| # session file exist. |
| if (os.path.isdir(CONFIG_DIR) or os.path.isfile(SESSION_FILE_PATH) or |
| os.path.isfile(SYSTEM_SESSION_FILE_PATH)): |
| return True |
| |
| # The host has been tested only on Ubuntu. |
| distribution = platform.linux_distribution() |
| return (distribution[0]).lower() == 'ubuntu' |
| |
| |
| def get_randr_supporting_x_server(): |
| """Returns a path to an X server that supports the RANDR extension, if this |
| is found on the system. Otherwise returns None.""" |
| try: |
| xvfb = "/usr/bin/Xvfb-randr" |
| if not os.path.exists(xvfb): |
| xvfb = locate_executable("Xvfb-randr") |
| return xvfb |
| except Exception: |
| return None |
| |
| |
| class Config: |
| def __init__(self, path): |
| self.path = path |
| self.data = {} |
| self.changed = False |
| |
| def load(self): |
| """Loads the config from file. |
| |
| Raises: |
| IOError: Error reading data |
| ValueError: Error parsing JSON |
| """ |
| settings_file = open(self.path, 'r') |
| self.data = json.load(settings_file) |
| self.changed = False |
| settings_file.close() |
| |
| def save(self): |
| """Saves the config to file. |
| |
| Raises: |
| IOError: Error writing data |
| TypeError: Error serialising JSON |
| """ |
| if not self.changed: |
| return |
| old_umask = os.umask(0066) |
| try: |
| settings_file = open(self.path, 'w') |
| settings_file.write(json.dumps(self.data, indent=2)) |
| settings_file.close() |
| self.changed = False |
| finally: |
| os.umask(old_umask) |
| |
| def save_and_log_errors(self): |
| """Calls self.save(), trapping and logging any errors.""" |
| try: |
| self.save() |
| except (IOError, TypeError) as e: |
| logging.error("Failed to save config: " + str(e)) |
| |
| def get(self, key): |
| return self.data.get(key) |
| |
| def __getitem__(self, key): |
| return self.data[key] |
| |
| def __setitem__(self, key, value): |
| self.data[key] = value |
| self.changed = True |
| |
| def clear(self): |
| self.data = {} |
| self.changed = True |
| |
| |
| class Authentication: |
| """Manage authentication tokens for Chromoting/xmpp""" |
| |
| def __init__(self): |
| self.login = None |
| self.oauth_refresh_token = None |
| |
| def copy_from(self, config): |
| """Loads the config and returns false if the config is invalid.""" |
| try: |
| self.login = config["xmpp_login"] |
| self.oauth_refresh_token = config["oauth_refresh_token"] |
| except KeyError: |
| return False |
| return True |
| |
| def copy_to(self, config): |
| config["xmpp_login"] = self.login |
| config["oauth_refresh_token"] = self.oauth_refresh_token |
| |
| |
| class Host: |
| """This manages the configuration for a host.""" |
| |
| def __init__(self): |
| self.host_id = str(uuid.uuid1()) |
| self.host_name = socket.gethostname() |
| self.host_secret_hash = None |
| self.private_key = None |
| |
| def copy_from(self, config): |
| try: |
| self.host_id = config["host_id"] |
| self.host_name = config["host_name"] |
| self.host_secret_hash = config.get("host_secret_hash") |
| self.private_key = config["private_key"] |
| except KeyError: |
| return False |
| return True |
| |
| def copy_to(self, config): |
| config["host_id"] = self.host_id |
| config["host_name"] = self.host_name |
| config["host_secret_hash"] = self.host_secret_hash |
| config["private_key"] = self.private_key |
| |
| |
| class Desktop: |
| """Manage a single virtual desktop""" |
| |
| def __init__(self, sizes): |
| self.x_proc = None |
| self.session_proc = None |
| self.host_proc = None |
| self.child_env = None |
| self.sizes = sizes |
| self.pulseaudio_pipe = None |
| self.server_supports_exact_resize = False |
| self.host_ready = False |
| self.ssh_auth_sockname = None |
| g_desktops.append(self) |
| |
| @staticmethod |
| def get_unused_display_number(): |
| """Return a candidate display number for which there is currently no |
| X Server lock file""" |
| display = FIRST_X_DISPLAY_NUMBER |
| while os.path.exists(X_LOCK_FILE_TEMPLATE % display): |
| display += 1 |
| return display |
| |
| def _init_child_env(self): |
| # Create clean environment for new session, so it is cleanly separated from |
| # the user's console X session. |
| self.child_env = {} |
| |
| for key in [ |
| "HOME", |
| "LANG", |
| "LOGNAME", |
| "PATH", |
| "SHELL", |
| "USER", |
| "USERNAME", |
| LOG_FILE_ENV_VAR]: |
| if os.environ.has_key(key): |
| self.child_env[key] = os.environ[key] |
| |
| # Ensure that the software-rendering GL drivers are loaded by the desktop |
| # session, instead of any hardware GL drivers installed on the system. |
| self.child_env["LD_LIBRARY_PATH"] = ( |
| "/usr/lib/%(arch)s-linux-gnu/mesa:" |
| "/usr/lib/%(arch)s-linux-gnu/dri:" |
| "/usr/lib/%(arch)s-linux-gnu/gallium-pipe" % |
| { "arch": platform.machine() }) |
| |
| # Read from /etc/environment if it exists, as it is a standard place to |
| # store system-wide environment settings. During a normal login, this would |
| # typically be done by the pam_env PAM module, depending on the local PAM |
| # configuration. |
| env_filename = "/etc/environment" |
| try: |
| with open(env_filename, "r") as env_file: |
| for line in env_file: |
| line = line.rstrip("\n") |
| # Split at the first "=", leaving any further instances in the value. |
| key_value_pair = line.split("=", 1) |
| if len(key_value_pair) == 2: |
| key, value = tuple(key_value_pair) |
| # The file stores key=value assignments, but the value may be |
| # quoted, so strip leading & trailing quotes from it. |
| value = value.strip("'\"") |
| self.child_env[key] = value |
| except IOError: |
| logging.info("Failed to read %s, skipping." % env_filename) |
| |
| def _setup_pulseaudio(self): |
| self.pulseaudio_pipe = None |
| |
| # pulseaudio uses UNIX sockets for communication. Length of UNIX socket |
| # name is limited to 108 characters, so audio will not work properly if |
| # the path is too long. To workaround this problem we use only first 10 |
| # symbols of the host hash. |
| pulse_path = os.path.join(CONFIG_DIR, |
| "pulseaudio#%s" % g_host_hash[0:10]) |
| if len(pulse_path) + len("/native") >= 108: |
| logging.error("Audio will not be enabled because pulseaudio UNIX " + |
| "socket path is too long.") |
| return False |
| |
| sink_name = "chrome_remote_desktop_session" |
| pipe_name = os.path.join(pulse_path, "fifo_output") |
| |
| try: |
| if not os.path.exists(pulse_path): |
| os.mkdir(pulse_path) |
| except IOError, e: |
| logging.error("Failed to create pulseaudio pipe: " + str(e)) |
| return False |
| |
| try: |
| pulse_config = open(os.path.join(pulse_path, "daemon.conf"), "w") |
| pulse_config.write("default-sample-format = s16le\n") |
| pulse_config.write("default-sample-rate = 48000\n") |
| pulse_config.write("default-sample-channels = 2\n") |
| pulse_config.close() |
| |
| pulse_script = open(os.path.join(pulse_path, "default.pa"), "w") |
| pulse_script.write("load-module module-native-protocol-unix\n") |
| pulse_script.write( |
| ("load-module module-pipe-sink sink_name=%s file=\"%s\" " + |
| "rate=48000 channels=2 format=s16le\n") % |
| (sink_name, pipe_name)) |
| pulse_script.close() |
| except IOError, e: |
| logging.error("Failed to write pulseaudio config: " + str(e)) |
| return False |
| |
| self.child_env["PULSE_CONFIG_PATH"] = pulse_path |
| self.child_env["PULSE_RUNTIME_PATH"] = pulse_path |
| self.child_env["PULSE_STATE_PATH"] = pulse_path |
| self.child_env["PULSE_SINK"] = sink_name |
| self.pulseaudio_pipe = pipe_name |
| |
| return True |
| |
| def _setup_gnubby(self): |
| self.ssh_auth_sockname = ("/tmp/chromoting.%s.ssh_auth_sock" % |
| os.environ["USER"]) |
| |
| def _launch_x_server(self, extra_x_args): |
| x_auth_file = os.path.expanduser("~/.Xauthority") |
| self.child_env["XAUTHORITY"] = x_auth_file |
| devnull = open(os.devnull, "rw") |
| display = self.get_unused_display_number() |
| |
| # Run "xauth add" with |child_env| so that it modifies the same XAUTHORITY |
| # file which will be used for the X session. |
| ret_code = subprocess.call("xauth add :%d . `mcookie`" % display, |
| env=self.child_env, shell=True) |
| if ret_code != 0: |
| raise Exception("xauth failed with code %d" % ret_code) |
| |
| max_width = max([width for width, height in self.sizes]) |
| max_height = max([height for width, height in self.sizes]) |
| |
| xvfb = get_randr_supporting_x_server() |
| if xvfb: |
| self.server_supports_exact_resize = True |
| else: |
| xvfb = "Xvfb" |
| self.server_supports_exact_resize = False |
| |
| # Disable the Composite extension iff the X session is the default |
| # Unity-2D, since it uses Metacity which fails to generate DAMAGE |
| # notifications correctly. See crbug.com/166468. |
| x_session = choose_x_session() |
| if (len(x_session) == 2 and |
| x_session[1] == "/usr/bin/gnome-session --session=ubuntu-2d"): |
| extra_x_args.extend(["-extension", "Composite"]) |
| |
| logging.info("Starting %s on display :%d" % (xvfb, display)) |
| screen_option = "%dx%dx24" % (max_width, max_height) |
| self.x_proc = subprocess.Popen( |
| [xvfb, ":%d" % display, |
| "-auth", x_auth_file, |
| "-nolisten", "tcp", |
| "-noreset", |
| "-screen", "0", screen_option |
| ] + extra_x_args) |
| if not self.x_proc.pid: |
| raise Exception("Could not start Xvfb.") |
| |
| self.child_env["DISPLAY"] = ":%d" % display |
| self.child_env["CHROME_REMOTE_DESKTOP_SESSION"] = "1" |
| |
| # Use a separate profile for any instances of Chrome that are started in |
| # the virtual session. Chrome doesn't support sharing a profile between |
| # multiple DISPLAYs, but Chrome Sync allows for a reasonable compromise. |
| chrome_profile = os.path.join(CONFIG_DIR, "chrome-profile") |
| self.child_env["CHROME_USER_DATA_DIR"] = chrome_profile |
| |
| # Set SSH_AUTH_SOCK to the file name to listen on. |
| if self.ssh_auth_sockname: |
| self.child_env["SSH_AUTH_SOCK"] = self.ssh_auth_sockname |
| |
| # Wait for X to be active. |
| for _test in range(5): |
| proc = subprocess.Popen("xdpyinfo", env=self.child_env, stdout=devnull) |
| _pid, retcode = os.waitpid(proc.pid, 0) |
| if retcode == 0: |
| break |
| time.sleep(0.5) |
| if retcode != 0: |
| raise Exception("Could not connect to Xvfb.") |
| else: |
| logging.info("Xvfb is active.") |
| |
| # The remoting host expects the server to use "evdev" keycodes, but Xvfb |
| # starts configured to use the "base" ruleset, resulting in XKB configuring |
| # for "xfree86" keycodes, and screwing up some keys. See crbug.com/119013. |
| # Reconfigure the X server to use "evdev" keymap rules. The X server must |
| # be started with -noreset otherwise it'll reset as soon as the command |
| # completes, since there are no other X clients running yet. |
| proc = subprocess.Popen("setxkbmap -rules evdev", env=self.child_env, |
| shell=True) |
| _pid, retcode = os.waitpid(proc.pid, 0) |
| if retcode != 0: |
| logging.error("Failed to set XKB to 'evdev'") |
| |
| # Register the screen sizes if the X server's RANDR extension supports it. |
| # Errors here are non-fatal; the X server will continue to run with the |
| # dimensions from the "-screen" option. |
| for width, height in self.sizes: |
| label = "%dx%d" % (width, height) |
| args = ["xrandr", "--newmode", label, "0", str(width), "0", "0", "0", |
| str(height), "0", "0", "0"] |
| subprocess.call(args, env=self.child_env, stdout=devnull, stderr=devnull) |
| args = ["xrandr", "--addmode", "screen", label] |
| subprocess.call(args, env=self.child_env, stdout=devnull, stderr=devnull) |
| |
| # Set the initial mode to the first size specified, otherwise the X server |
| # would default to (max_width, max_height), which might not even be in the |
| # list. |
| label = "%dx%d" % self.sizes[0] |
| args = ["xrandr", "-s", label] |
| subprocess.call(args, env=self.child_env, stdout=devnull, stderr=devnull) |
| |
| # Set the physical size of the display so that the initial mode is running |
| # at approximately 96 DPI, since some desktops require the DPI to be set to |
| # something realistic. |
| args = ["xrandr", "--dpi", "96"] |
| subprocess.call(args, env=self.child_env, stdout=devnull, stderr=devnull) |
| |
| devnull.close() |
| |
| def _launch_x_session(self): |
| # Start desktop session. |
| # The /dev/null input redirection is necessary to prevent the X session |
| # reading from stdin. If this code runs as a shell background job in a |
| # terminal, any reading from stdin causes the job to be suspended. |
| # Daemonization would solve this problem by separating the process from the |
| # controlling terminal. |
| xsession_command = choose_x_session() |
| if xsession_command is None: |
| raise Exception("Unable to choose suitable X session command.") |
| |
| logging.info("Launching X session: %s" % xsession_command) |
| self.session_proc = subprocess.Popen(xsession_command, |
| stdin=open(os.devnull, "r"), |
| cwd=HOME_DIR, |
| env=self.child_env) |
| if not self.session_proc.pid: |
| raise Exception("Could not start X session") |
| |
| def launch_session(self, x_args): |
| self._init_child_env() |
| self._setup_pulseaudio() |
| self._setup_gnubby() |
| self._launch_x_server(x_args) |
| self._launch_x_session() |
| |
| def launch_host(self, host_config): |
| # Start remoting host |
| args = [locate_executable(HOST_BINARY_NAME), "--host-config=-"] |
| if self.pulseaudio_pipe: |
| args.append("--audio-pipe-name=%s" % self.pulseaudio_pipe) |
| if self.server_supports_exact_resize: |
| args.append("--server-supports-exact-resize") |
| if self.ssh_auth_sockname: |
| args.append("--ssh-auth-sockname=%s" % self.ssh_auth_sockname) |
| |
| # Have the host process use SIGUSR1 to signal a successful start. |
| def sigusr1_handler(signum, frame): |
| _ = signum, frame |
| logging.info("Host ready to receive connections.") |
| self.host_ready = True |
| if (ParentProcessLogger.instance() and |
| False not in [desktop.host_ready for desktop in g_desktops]): |
| ParentProcessLogger.instance().release_parent() |
| |
| signal.signal(signal.SIGUSR1, sigusr1_handler) |
| args.append("--signal-parent") |
| |
| self.host_proc = subprocess.Popen(args, env=self.child_env, |
| stdin=subprocess.PIPE) |
| logging.info(args) |
| if not self.host_proc.pid: |
| raise Exception("Could not start Chrome Remote Desktop host") |
| self.host_proc.stdin.write(json.dumps(host_config.data)) |
| self.host_proc.stdin.close() |
| |
| |
| def get_daemon_proc(): |
| """Checks if there is already an instance of this script running, and returns |
| a psutil.Process instance for it. |
| |
| Returns: |
| A Process instance for the existing daemon process, or None if the daemon |
| is not running. |
| """ |
| |
| uid = os.getuid() |
| this_pid = os.getpid() |
| |
| # Support new & old psutil API. This is the right way to check, according to |
| # http://grodola.blogspot.com/2014/01/psutil-20-porting.html |
| if psutil.version_info >= (2, 0): |
| psget = lambda x: x() |
| else: |
| psget = lambda x: x |
| |
| for process in psutil.process_iter(): |
| # Skip any processes that raise an exception, as processes may terminate |
| # during iteration over the list. |
| try: |
| # Skip other users' processes. |
| if psget(process.uids).real != uid: |
| continue |
| |
| # Skip the process for this instance. |
| if process.pid == this_pid: |
| continue |
| |
| # |cmdline| will be [python-interpreter, script-file, other arguments...] |
| cmdline = psget(process.cmdline) |
| if len(cmdline) < 2: |
| continue |
| if cmdline[0] == sys.executable and cmdline[1] == sys.argv[0]: |
| return process |
| except (psutil.NoSuchProcess, psutil.AccessDenied): |
| continue |
| |
| return None |
| |
| |
| def choose_x_session(): |
| """Chooses the most appropriate X session command for this system. |
| |
| Returns: |
| A string containing the command to run, or a list of strings containing |
| the executable program and its arguments, which is suitable for passing as |
| the first parameter of subprocess.Popen(). If a suitable session cannot |
| be found, returns None. |
| """ |
| XSESSION_FILES = [ |
| SESSION_FILE_PATH, |
| SYSTEM_SESSION_FILE_PATH ] |
| for startup_file in XSESSION_FILES: |
| startup_file = os.path.expanduser(startup_file) |
| if os.path.exists(startup_file): |
| if os.access(startup_file, os.X_OK): |
| # "/bin/sh -c" is smart about how to execute the session script and |
| # works in cases where plain exec() fails (for example, if the file is |
| # marked executable, but is a plain script with no shebang line). |
| return ["/bin/sh", "-c", pipes.quote(startup_file)] |
| else: |
| # If this is a system-wide session script, it should be run using the |
| # system shell, ignoring any login shell that might be set for the |
| # current user. |
| return ["/bin/sh", startup_file] |
| |
| # Choose a session wrapper script to run the session. On some systems, |
| # /etc/X11/Xsession fails to load the user's .profile, so look for an |
| # alternative wrapper that is more likely to match the script that the |
| # system actually uses for console desktop sessions. |
| SESSION_WRAPPERS = [ |
| "/usr/sbin/lightdm-session", |
| "/etc/gdm/Xsession", |
| "/etc/X11/Xsession" ] |
| for session_wrapper in SESSION_WRAPPERS: |
| if os.path.exists(session_wrapper): |
| if os.path.exists("/usr/bin/unity-2d-panel"): |
| # On Ubuntu 12.04, the default session relies on 3D-accelerated |
| # hardware. Trying to run this with a virtual X display produces |
| # weird results on some systems (for example, upside-down and |
| # corrupt displays). So if the ubuntu-2d session is available, |
| # choose it explicitly. |
| return [session_wrapper, "/usr/bin/gnome-session --session=ubuntu-2d"] |
| else: |
| # Use the session wrapper by itself, and let the system choose a |
| # session. |
| return [session_wrapper] |
| return None |
| |
| |
| def locate_executable(exe_name): |
| if IS_INSTALLED: |
| # If the script is running from its installed location, search the host |
| # binary only in the same directory. |
| paths_to_try = [ SCRIPT_PATH ] |
| else: |
| paths_to_try = map(lambda p: os.path.join(SCRIPT_PATH, p), |
| [".", "../../../out/Debug", "../../../out/Release" ]) |
| for path in paths_to_try: |
| exe_path = os.path.join(path, exe_name) |
| if os.path.exists(exe_path): |
| return exe_path |
| |
| raise Exception("Could not locate executable '%s'" % exe_name) |
| |
| |
| class ParentProcessLogger(object): |
| """Redirects logs to the parent process, until the host is ready or quits. |
| |
| This class creates a pipe to allow logging from the daemon process to be |
| copied to the parent process. The daemon process adds a log-handler that |
| directs logging output to the pipe. The parent process reads from this pipe |
| until and writes the content to stderr. When the pipe is no longer needed |
| (for example, the host signals successful launch or permanent failure), the |
| daemon removes the log-handler and closes the pipe, causing the the parent |
| process to reach end-of-file while reading the pipe and exit. |
| |
| The (singleton) logger should be instantiated before forking. The parent |
| process should call wait_for_logs() before exiting. The (grand-)child process |
| should call start_logging() when it starts, and then use logging.* to issue |
| log statements, as usual. When the child has either succesfully started the |
| host or terminated, it must call release_parent() to allow the parent to exit. |
| """ |
| |
| __instance = None |
| |
| def __init__(self): |
| """Constructor. Must be called before forking.""" |
| read_pipe, write_pipe = os.pipe() |
| # Ensure write_pipe is closed on exec, otherwise it will be kept open by |
| # child processes (X, host), preventing the read pipe from EOF'ing. |
| old_flags = fcntl.fcntl(write_pipe, fcntl.F_GETFD) |
| fcntl.fcntl(write_pipe, fcntl.F_SETFD, old_flags | fcntl.FD_CLOEXEC) |
| self._read_file = os.fdopen(read_pipe, 'r') |
| self._write_file = os.fdopen(write_pipe, 'a') |
| self._logging_handler = None |
| ParentProcessLogger.__instance = self |
| |
| def start_logging(self): |
| """Installs a logging handler that sends log entries to a pipe. |
| |
| Must be called by the child process. |
| """ |
| self._read_file.close() |
| self._logging_handler = logging.StreamHandler(self._write_file) |
| logging.getLogger().addHandler(self._logging_handler) |
| |
| def release_parent(self): |
| """Uninstalls logging handler and closes the pipe, releasing the parent. |
| |
| Must be called by the child process. |
| """ |
| if self._logging_handler: |
| logging.getLogger().removeHandler(self._logging_handler) |
| self._logging_handler = None |
| if not self._write_file.closed: |
| self._write_file.close() |
| |
| def wait_for_logs(self): |
| """Waits and prints log lines from the daemon until the pipe is closed. |
| |
| Must be called by the parent process. |
| """ |
| # If Ctrl-C is pressed, inform the user that the daemon is still running. |
| # This signal will cause the read loop below to stop with an EINTR IOError. |
| def sigint_handler(signum, frame): |
| _ = signum, frame |
| print >> sys.stderr, ("Interrupted. The daemon is still running in the " |
| "background.") |
| |
| signal.signal(signal.SIGINT, sigint_handler) |
| |
| # Install a fallback timeout to release the parent process, in case the |
| # daemon never responds (e.g. host crash-looping, daemon killed). |
| # This signal will cause the read loop below to stop with an EINTR IOError. |
| def sigalrm_handler(signum, frame): |
| _ = signum, frame |
| print >> sys.stderr, ("No response from daemon. It may have crashed, or " |
| "may still be running in the background.") |
| |
| signal.signal(signal.SIGALRM, sigalrm_handler) |
| signal.alarm(30) |
| |
| self._write_file.close() |
| |
| # Print lines as they're logged to the pipe until EOF is reached or readline |
| # is interrupted by one of the signal handlers above. |
| try: |
| for line in iter(self._read_file.readline, ''): |
| sys.stderr.write(line) |
| except IOError as e: |
| if e.errno != errno.EINTR: |
| raise |
| print >> sys.stderr, "Log file: %s" % os.environ[LOG_FILE_ENV_VAR] |
| |
| @staticmethod |
| def instance(): |
| """Returns the singleton instance, if it exists.""" |
| return ParentProcessLogger.__instance |
| |
| |
| def daemonize(): |
| """Background this process and detach from controlling terminal, redirecting |
| stdout/stderr to a log file.""" |
| |
| # TODO(lambroslambrou): Having stdout/stderr redirected to a log file is not |
| # ideal - it could create a filesystem DoS if the daemon or a child process |
| # were to write excessive amounts to stdout/stderr. Ideally, stdout/stderr |
| # should be redirected to a pipe or socket, and a process at the other end |
| # should consume the data and write it to a logging facility which can do |
| # data-capping or log-rotation. The 'logger' command-line utility could be |
| # used for this, but it might cause too much syslog spam. |
| |
| # Create new (temporary) file-descriptors before forking, so any errors get |
| # reported to the main process and set the correct exit-code. |
| # The mode is provided, since Python otherwise sets a default mode of 0777, |
| # which would result in the new file having permissions of 0777 & ~umask, |
| # possibly leaving the executable bits set. |
| if not os.environ.has_key(LOG_FILE_ENV_VAR): |
| log_file_prefix = "chrome_remote_desktop_%s_" % time.strftime( |
| '%Y%m%d_%H%M%S', time.localtime(time.time())) |
| log_file = tempfile.NamedTemporaryFile(prefix=log_file_prefix, delete=False) |
| os.environ[LOG_FILE_ENV_VAR] = log_file.name |
| log_fd = log_file.file.fileno() |
| else: |
| log_fd = os.open(os.environ[LOG_FILE_ENV_VAR], |
| os.O_WRONLY | os.O_CREAT | os.O_APPEND, 0600) |
| |
| devnull_fd = os.open(os.devnull, os.O_RDONLY) |
| |
| parent_logger = ParentProcessLogger() |
| |
| pid = os.fork() |
| |
| if pid == 0: |
| # Child process |
| os.setsid() |
| |
| # The second fork ensures that the daemon isn't a session leader, so that |
| # it doesn't acquire a controlling terminal. |
| pid = os.fork() |
| |
| if pid == 0: |
| # Grandchild process |
| pass |
| else: |
| # Child process |
| os._exit(0) # pylint: disable=W0212 |
| else: |
| # Parent process |
| parent_logger.wait_for_logs() |
| os._exit(0) # pylint: disable=W0212 |
| |
| logging.info("Daemon process started in the background, logging to '%s'" % |
| os.environ[LOG_FILE_ENV_VAR]) |
| |
| os.chdir(HOME_DIR) |
| |
| parent_logger.start_logging() |
| |
| # Copy the file-descriptors to create new stdin, stdout and stderr. Note |
| # that dup2(oldfd, newfd) closes newfd first, so this will close the current |
| # stdin, stdout and stderr, detaching from the terminal. |
| os.dup2(devnull_fd, sys.stdin.fileno()) |
| os.dup2(log_fd, sys.stdout.fileno()) |
| os.dup2(log_fd, sys.stderr.fileno()) |
| |
| # Close the temporary file-descriptors. |
| os.close(devnull_fd) |
| os.close(log_fd) |
| |
| |
| def cleanup(): |
| logging.info("Cleanup.") |
| |
| global g_desktops |
| for desktop in g_desktops: |
| for proc, name in [(desktop.x_proc, "Xvfb"), |
| (desktop.session_proc, "session"), |
| (desktop.host_proc, "host")]: |
| if proc is not None: |
| logging.info("Terminating " + name) |
| try: |
| psutil_proc = psutil.Process(proc.pid) |
| psutil_proc.terminate() |
| |
| # Use a short timeout, to avoid delaying service shutdown if the |
| # process refuses to die for some reason. |
| psutil_proc.wait(timeout=10) |
| except psutil.TimeoutExpired: |
| logging.error("Timed out - sending SIGKILL") |
| psutil_proc.kill() |
| except psutil.Error: |
| logging.error("Error terminating process") |
| |
| g_desktops = [] |
| if ParentProcessLogger.instance(): |
| ParentProcessLogger.instance().release_parent() |
| |
| class SignalHandler: |
| """Reload the config file on SIGHUP. Since we pass the configuration to the |
| host processes via stdin, they can't reload it, so terminate them. They will |
| be relaunched automatically with the new config.""" |
| |
| def __init__(self, host_config): |
| self.host_config = host_config |
| |
| def __call__(self, signum, _stackframe): |
| if signum == signal.SIGHUP: |
| logging.info("SIGHUP caught, restarting host.") |
| try: |
| self.host_config.load() |
| except (IOError, ValueError) as e: |
| logging.error("Failed to load config: " + str(e)) |
| for desktop in g_desktops: |
| if desktop.host_proc: |
| desktop.host_proc.send_signal(signal.SIGTERM) |
| else: |
| # Exit cleanly so the atexit handler, cleanup(), gets called. |
| raise SystemExit |
| |
| |
| class RelaunchInhibitor: |
| """Helper class for inhibiting launch of a child process before a timeout has |
| elapsed. |
| |
| A managed process can be in one of these states: |
| running, not inhibited (running == True) |
| stopped and inhibited (running == False and is_inhibited() == True) |
| stopped but not inhibited (running == False and is_inhibited() == False) |
| |
| Attributes: |
| label: Name of the tracked process. Only used for logging. |
| running: Whether the process is currently running. |
| earliest_relaunch_time: Time before which the process should not be |
| relaunched, or 0 if there is no limit. |
| failures: The number of times that the process ran for less than a |
| specified timeout, and had to be inhibited. This count is reset to 0 |
| whenever the process has run for longer than the timeout. |
| """ |
| |
| def __init__(self, label): |
| self.label = label |
| self.running = False |
| self.earliest_relaunch_time = 0 |
| self.earliest_successful_termination = 0 |
| self.failures = 0 |
| |
| def is_inhibited(self): |
| return (not self.running) and (time.time() < self.earliest_relaunch_time) |
| |
| def record_started(self, minimum_lifetime, relaunch_delay): |
| """Record that the process was launched, and set the inhibit time to |
| |timeout| seconds in the future.""" |
| self.earliest_relaunch_time = time.time() + relaunch_delay |
| self.earliest_successful_termination = time.time() + minimum_lifetime |
| self.running = True |
| |
| def record_stopped(self): |
| """Record that the process was stopped, and adjust the failure count |
| depending on whether the process ran long enough.""" |
| self.running = False |
| if time.time() < self.earliest_successful_termination: |
| self.failures += 1 |
| else: |
| self.failures = 0 |
| logging.info("Failure count for '%s' is now %d", self.label, self.failures) |
| |
| |
| def relaunch_self(): |
| cleanup() |
| os.execvp(sys.argv[0], sys.argv) |
| |
| |
| def waitpid_with_timeout(pid, deadline): |
| """Wrapper around os.waitpid() which waits until either a child process dies |
| or the deadline elapses. |
| |
| Args: |
| pid: Process ID to wait for, or -1 to wait for any child process. |
| deadline: Waiting stops when time.time() exceeds this value. |
| |
| Returns: |
| (pid, status): Same as for os.waitpid(), except that |pid| is 0 if no child |
| changed state within the timeout. |
| |
| Raises: |
| Same as for os.waitpid(). |
| """ |
| while time.time() < deadline: |
| pid, status = os.waitpid(pid, os.WNOHANG) |
| if pid != 0: |
| return (pid, status) |
| time.sleep(1) |
| return (0, 0) |
| |
| |
| def waitpid_handle_exceptions(pid, deadline): |
| """Wrapper around os.waitpid()/waitpid_with_timeout(), which waits until |
| either a child process exits or the deadline elapses, and retries if certain |
| exceptions occur. |
| |
| Args: |
| pid: Process ID to wait for, or -1 to wait for any child process. |
| deadline: If non-zero, waiting stops when time.time() exceeds this value. |
| If zero, waiting stops when a child process exits. |
| |
| Returns: |
| (pid, status): Same as for waitpid_with_timeout(). |pid| is non-zero if and |
| only if a child exited during the wait. |
| |
| Raises: |
| Same as for os.waitpid(), except: |
| OSError with errno==EINTR causes the wait to be retried (this can happen, |
| for example, if this parent process receives SIGHUP). |
| OSError with errno==ECHILD means there are no child processes, and so |
| this function sleeps until |deadline|. If |deadline| is zero, this is an |
| error and the OSError exception is raised in this case. |
| """ |
| while True: |
| try: |
| if deadline == 0: |
| pid_result, status = os.waitpid(pid, 0) |
| else: |
| pid_result, status = waitpid_with_timeout(pid, deadline) |
| return (pid_result, status) |
| except OSError, e: |
| if e.errno == errno.EINTR: |
| continue |
| elif e.errno == errno.ECHILD: |
| now = time.time() |
| if deadline == 0: |
| # No time-limit and no child processes. This is treated as an error |
| # (see docstring). |
| raise |
| elif deadline > now: |
| time.sleep(deadline - now) |
| return (0, 0) |
| else: |
| # Anything else is an unexpected error. |
| raise |
| |
| |
| def main(): |
| EPILOG = """This script is not intended for use by end-users. To configure |
| Chrome Remote Desktop, please install the app from the Chrome |
| Web Store: https://chrome.google.com/remotedesktop""" |
| parser = optparse.OptionParser( |
| usage="Usage: %prog [options] [ -- [ X server options ] ]", |
| epilog=EPILOG) |
| parser.add_option("-s", "--size", dest="size", action="append", |
| help="Dimensions of virtual desktop. This can be specified " |
| "multiple times to make multiple screen resolutions " |
| "available (if the Xvfb server supports this).") |
| parser.add_option("-f", "--foreground", dest="foreground", default=False, |
| action="store_true", |
| help="Don't run as a background daemon.") |
| parser.add_option("", "--start", dest="start", default=False, |
| action="store_true", |
| help="Start the host.") |
| parser.add_option("-k", "--stop", dest="stop", default=False, |
| action="store_true", |
| help="Stop the daemon currently running.") |
| parser.add_option("", "--get-status", dest="get_status", default=False, |
| action="store_true", |
| help="Prints host status") |
| parser.add_option("", "--check-running", dest="check_running", default=False, |
| action="store_true", |
| help="Return 0 if the daemon is running, or 1 otherwise.") |
| parser.add_option("", "--config", dest="config", action="store", |
| help="Use the specified configuration file.") |
| parser.add_option("", "--reload", dest="reload", default=False, |
| action="store_true", |
| help="Signal currently running host to reload the config.") |
| parser.add_option("", "--add-user", dest="add_user", default=False, |
| action="store_true", |
| help="Add current user to the chrome-remote-desktop group.") |
| parser.add_option("", "--host-version", dest="host_version", default=False, |
| action="store_true", |
| help="Prints version of the host.") |
| (options, args) = parser.parse_args() |
| |
| # Determine the filename of the host configuration and PID files. |
| if not options.config: |
| options.config = os.path.join(CONFIG_DIR, "host#%s.json" % g_host_hash) |
| |
| # Check for a modal command-line option (start, stop, etc.) |
| |
| if options.get_status: |
| proc = get_daemon_proc() |
| if proc is not None: |
| print "STARTED" |
| elif is_supported_platform(): |
| print "STOPPED" |
| else: |
| print "NOT_IMPLEMENTED" |
| return 0 |
| |
| # TODO(sergeyu): Remove --check-running once NPAPI plugin and NM host are |
| # updated to always use get-status flag instead. |
| if options.check_running: |
| proc = get_daemon_proc() |
| return 1 if proc is None else 0 |
| |
| if options.stop: |
| proc = get_daemon_proc() |
| if proc is None: |
| print "The daemon is not currently running" |
| else: |
| print "Killing process %s" % proc.pid |
| proc.terminate() |
| try: |
| proc.wait(timeout=30) |
| except psutil.TimeoutExpired: |
| print "Timed out trying to kill daemon process" |
| return 1 |
| return 0 |
| |
| if options.reload: |
| proc = get_daemon_proc() |
| if proc is None: |
| return 1 |
| proc.send_signal(signal.SIGHUP) |
| return 0 |
| |
| if options.add_user: |
| user = getpass.getuser() |
| try: |
| if user in grp.getgrnam(CHROME_REMOTING_GROUP_NAME).gr_mem: |
| logging.info("User '%s' is already a member of '%s'." % |
| (user, CHROME_REMOTING_GROUP_NAME)) |
| return 0 |
| except KeyError: |
| logging.info("Group '%s' not found." % CHROME_REMOTING_GROUP_NAME) |
| |
| if os.getenv("DISPLAY"): |
| sudo_command = "gksudo --description \"Chrome Remote Desktop\"" |
| else: |
| sudo_command = "sudo" |
| command = ("sudo -k && exec %(sudo)s -- sh -c " |
| "\"groupadd -f %(group)s && gpasswd --add %(user)s %(group)s\"" % |
| { 'group': CHROME_REMOTING_GROUP_NAME, |
| 'user': user, |
| 'sudo': sudo_command }) |
| os.execv("/bin/sh", ["/bin/sh", "-c", command]) |
| return 1 |
| |
| if options.host_version: |
| # TODO(sergeyu): Also check RPM package version once we add RPM package. |
| return os.system(locate_executable(HOST_BINARY_NAME) + " --version") >> 8 |
| |
| if not options.start: |
| # If no modal command-line options specified, print an error and exit. |
| print >> sys.stderr, EPILOG |
| return 1 |
| |
| # If a RANDR-supporting Xvfb is not available, limit the default size to |
| # something more sensible. |
| if get_randr_supporting_x_server(): |
| default_sizes = DEFAULT_SIZES |
| else: |
| default_sizes = DEFAULT_SIZE_NO_RANDR |
| |
| # Collate the list of sizes that XRANDR should support. |
| if not options.size: |
| if os.environ.has_key(DEFAULT_SIZES_ENV_VAR): |
| default_sizes = os.environ[DEFAULT_SIZES_ENV_VAR] |
| options.size = default_sizes.split(",") |
| |
| sizes = [] |
| for size in options.size: |
| size_components = size.split("x") |
| if len(size_components) != 2: |
| parser.error("Incorrect size format '%s', should be WIDTHxHEIGHT" % size) |
| |
| try: |
| width = int(size_components[0]) |
| height = int(size_components[1]) |
| |
| # Enforce minimum desktop size, as a sanity-check. The limit of 100 will |
| # detect typos of 2 instead of 3 digits. |
| if width < 100 or height < 100: |
| raise ValueError |
| except ValueError: |
| parser.error("Width and height should be 100 pixels or greater") |
| |
| sizes.append((width, height)) |
| |
| # Register an exit handler to clean up session process and the PID file. |
| atexit.register(cleanup) |
| |
| # Load the initial host configuration. |
| host_config = Config(options.config) |
| try: |
| host_config.load() |
| except (IOError, ValueError) as e: |
| print >> sys.stderr, "Failed to load config: " + str(e) |
| return 1 |
| |
| # Register handler to re-load the configuration in response to signals. |
| for s in [signal.SIGHUP, signal.SIGINT, signal.SIGTERM]: |
| signal.signal(s, SignalHandler(host_config)) |
| |
| # Verify that the initial host configuration has the necessary fields. |
| auth = Authentication() |
| auth_config_valid = auth.copy_from(host_config) |
| host = Host() |
| host_config_valid = host.copy_from(host_config) |
| if not host_config_valid or not auth_config_valid: |
| logging.error("Failed to load host configuration.") |
| return 1 |
| |
| # Determine whether a desktop is already active for the specified host |
| # host configuration. |
| proc = get_daemon_proc() |
| if proc is not None: |
| # Debian policy requires that services should "start" cleanly and return 0 |
| # if they are already running. |
| print "Service already running." |
| return 0 |
| |
| # Detach a separate "daemon" process to run the session, unless specifically |
| # requested to run in the foreground. |
| if not options.foreground: |
| daemonize() |
| |
| logging.info("Using host_id: " + host.host_id) |
| |
| desktop = Desktop(sizes) |
| |
| # Keep track of the number of consecutive failures of any child process to |
| # run for longer than a set period of time. The script will exit after a |
| # threshold is exceeded. |
| # There is no point in tracking the X session process separately, since it is |
| # launched at (roughly) the same time as the X server, and the termination of |
| # one of these triggers the termination of the other. |
| x_server_inhibitor = RelaunchInhibitor("X server") |
| host_inhibitor = RelaunchInhibitor("host") |
| all_inhibitors = [x_server_inhibitor, host_inhibitor] |
| |
| # Don't allow relaunching the script on the first loop iteration. |
| allow_relaunch_self = False |
| |
| while True: |
| # Set the backoff interval and exit if a process failed too many times. |
| backoff_time = SHORT_BACKOFF_TIME |
| for inhibitor in all_inhibitors: |
| if inhibitor.failures >= MAX_LAUNCH_FAILURES: |
| logging.error("Too many launch failures of '%s', exiting." |
| % inhibitor.label) |
| return 1 |
| elif inhibitor.failures >= SHORT_BACKOFF_THRESHOLD: |
| backoff_time = LONG_BACKOFF_TIME |
| |
| relaunch_times = [] |
| |
| # If the session process or X server stops running (e.g. because the user |
| # logged out), kill the other. This will trigger the next conditional block |
| # as soon as os.waitpid() reaps its exit-code. |
| if desktop.session_proc is None and desktop.x_proc is not None: |
| logging.info("Terminating X server") |
| desktop.x_proc.terminate() |
| elif desktop.x_proc is None and desktop.session_proc is not None: |
| logging.info("Terminating X session") |
| desktop.session_proc.terminate() |
| elif desktop.x_proc is None and desktop.session_proc is None: |
| # Both processes have terminated. |
| if (allow_relaunch_self and x_server_inhibitor.failures == 0 and |
| host_inhibitor.failures == 0): |
| # Since the user's desktop is already gone at this point, there's no |
| # state to lose and now is a good time to pick up any updates to this |
| # script that might have been installed. |
| logging.info("Relaunching self") |
| relaunch_self() |
| else: |
| # If there is a non-zero |failures| count, restarting the whole script |
| # would lose this information, so just launch the session as normal. |
| if x_server_inhibitor.is_inhibited(): |
| logging.info("Waiting before launching X server") |
| relaunch_times.append(x_server_inhibitor.earliest_relaunch_time) |
| else: |
| logging.info("Launching X server and X session.") |
| desktop.launch_session(args) |
| x_server_inhibitor.record_started(MINIMUM_PROCESS_LIFETIME, |
| backoff_time) |
| allow_relaunch_self = True |
| |
| if desktop.host_proc is None: |
| if host_inhibitor.is_inhibited(): |
| logging.info("Waiting before launching host process") |
| relaunch_times.append(host_inhibitor.earliest_relaunch_time) |
| else: |
| logging.info("Launching host process") |
| desktop.launch_host(host_config) |
| host_inhibitor.record_started(MINIMUM_PROCESS_LIFETIME, |
| backoff_time) |
| |
| deadline = min(relaunch_times) if relaunch_times else 0 |
| pid, status = waitpid_handle_exceptions(-1, deadline) |
| if pid == 0: |
| continue |
| |
| logging.info("wait() returned (%s,%s)" % (pid, status)) |
| |
| # When a process has terminated, and we've reaped its exit-code, any Popen |
| # instance for that process is no longer valid. Reset any affected instance |
| # to None. |
| if desktop.x_proc is not None and pid == desktop.x_proc.pid: |
| logging.info("X server process terminated") |
| desktop.x_proc = None |
| x_server_inhibitor.record_stopped() |
| |
| if desktop.session_proc is not None and pid == desktop.session_proc.pid: |
| logging.info("Session process terminated") |
| desktop.session_proc = None |
| |
| if desktop.host_proc is not None and pid == desktop.host_proc.pid: |
| logging.info("Host process terminated") |
| desktop.host_proc = None |
| desktop.host_ready = False |
| host_inhibitor.record_stopped() |
| |
| # These exit-codes must match the ones used by the host. |
| # See remoting/host/host_error_codes.h. |
| # Delete the host or auth configuration depending on the returned error |
| # code, so the next time this script is run, a new configuration |
| # will be created and registered. |
| if os.WIFEXITED(status): |
| if os.WEXITSTATUS(status) == 100: |
| logging.info("Host configuration is invalid - exiting.") |
| return 0 |
| elif os.WEXITSTATUS(status) == 101: |
| logging.info("Host ID has been deleted - exiting.") |
| host_config.clear() |
| host_config.save_and_log_errors() |
| return 0 |
| elif os.WEXITSTATUS(status) == 102: |
| logging.info("OAuth credentials are invalid - exiting.") |
| return 0 |
| elif os.WEXITSTATUS(status) == 103: |
| logging.info("Host domain is blocked by policy - exiting.") |
| return 0 |
| # Nothing to do for Mac-only status 104 (login screen unsupported) |
| elif os.WEXITSTATUS(status) == 105: |
| logging.info("Username is blocked by policy - exiting.") |
| return 0 |
| else: |
| logging.info("Host exited with status %s." % os.WEXITSTATUS(status)) |
| elif os.WIFSIGNALED(status): |
| logging.info("Host terminated by signal %s." % os.WTERMSIG(status)) |
| |
| |
| if __name__ == "__main__": |
| logging.basicConfig(level=logging.DEBUG, |
| format="%(asctime)s:%(levelname)s:%(message)s") |
| sys.exit(main()) |
