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Mini Shell
Mini Shell
import fnmatch
import logging
import os
import select
import subprocess
import tempfile
import time
from threading import Lock
from pyvirtualdisplay import xauth
from pyvirtualdisplay.util import get_helptext, platform_is_osx
log = logging.getLogger(__name__)
# try:
# import fcntl
# except ImportError:
# fcntl = None
_mutex = Lock()
_mutex_popen = Lock()
_MIN_DISPLAY_NR = 1000
_USED_DISPLAY_NR_LIST = []
_X_START_TIMEOUT = 10
_X_START_TIME_STEP = 0.1
_X_START_WAIT = 0.1
class XStartTimeoutError(Exception):
pass
class XStartError(Exception):
pass
def _lock_files():
tmpdir = "/tmp"
try:
ls = os.listdir(tmpdir)
except FileNotFoundError:
log.warning("missing /tmp")
return []
pattern = ".X*-lock"
names = fnmatch.filter(ls, pattern)
ls = [os.path.join(tmpdir, child) for child in names]
ls = [p for p in ls if os.path.isfile(p)]
return ls
def _search_for_display():
# search for free display
ls = list(map(lambda x: int(x.split("X")[1].split("-")[0]), _lock_files()))
if len(ls):
display = max(_MIN_DISPLAY_NR, max(ls) + 3)
else:
display = _MIN_DISPLAY_NR
return display
class AbstractDisplay(object):
"""
Common parent for X servers (Xvfb,Xephyr,Xvnc)
"""
def __init__(self, program, use_xauth, retries, extra_args, manage_global_env):
self._extra_args = extra_args
self._retries = retries
self._program = program
self.stdout = None
self.stderr = None
self.old_display_var = None
self._subproc = None
self.display = None
self._is_started = False
self._manage_global_env = manage_global_env
self._reset_global_env = False
self._pipe_wfd = None
self._retries_current = 0
helptext = get_helptext(program)
self._has_displayfd = "-displayfd" in helptext
if not self._has_displayfd:
log.debug("-displayfd flag is missing.")
PYVIRTUALDISPLAY_DISPLAYFD = os.environ.get("PYVIRTUALDISPLAY_DISPLAYFD")
if PYVIRTUALDISPLAY_DISPLAYFD:
log.debug("PYVIRTUALDISPLAY_DISPLAYFD=%s", PYVIRTUALDISPLAY_DISPLAYFD)
# '0'->false, '1'->true
self._has_displayfd = bool(int(PYVIRTUALDISPLAY_DISPLAYFD))
else:
# TODO: macos: displayfd is available on XQuartz-2.7.11 but it doesn't work, always 0 is returned
if platform_is_osx():
self._has_displayfd = False
self._check_flags(helptext)
if use_xauth and not xauth.is_installed():
raise xauth.NotFoundError()
self._use_xauth = use_xauth
self._old_xauth = None
self._xauth_filename = None
def _check_flags(self, helptext):
pass
def _cmd(self):
raise NotImplementedError()
def _redirect_display(self, on):
"""
on:
* True -> set $DISPLAY to virtual screen
* False -> set $DISPLAY to original screen
:param on: bool
"""
d = self.new_display_var if on else self.old_display_var
if d is None:
log.debug("unset $DISPLAY")
try:
del os.environ["DISPLAY"]
except KeyError:
log.warning("$DISPLAY was already unset.")
else:
log.debug("set $DISPLAY=%s", d)
os.environ["DISPLAY"] = d
def _env(self):
env = os.environ.copy()
env["DISPLAY"] = self.new_display_var
return env
def start(self):
"""
start display
:rtype: self
"""
if self._is_started:
raise XStartError(self, "Display was started twice.")
self._is_started = True
if self._has_displayfd:
self._start1_has_displayfd()
else:
i = 0
while True:
self._retries_current = i + 1
try:
self._start1()
break
except XStartError:
log.warning("start failed %s", i + 1)
time.sleep(0.05)
i += 1
if i >= self._retries:
raise XStartError(
"No success after %s retries. Last stderr: %s"
% (self._retries, self.stderr)
)
if self._manage_global_env:
self._redirect_display(True)
self._reset_global_env = True
def _popen(self, use_pass_fds):
with _mutex_popen:
if use_pass_fds:
self._subproc = subprocess.Popen(
self._command,
pass_fds=[self._pipe_wfd],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
shell=False,
)
else:
self._subproc = subprocess.Popen(
self._command,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
shell=False,
)
def _start1_has_displayfd(self):
# stdout doesn't work on osx -> create own pipe
rfd, self._pipe_wfd = os.pipe()
self._command = self._cmd() + self._extra_args
log.debug("command: %s", self._command)
self._popen(use_pass_fds=True)
self.display = int(self._wait_for_pipe_text(rfd))
os.close(rfd)
os.close(self._pipe_wfd)
self.new_display_var = ":%s" % int(self.display)
if self._use_xauth:
self._setup_xauth()
# https://github.com/ponty/PyVirtualDisplay/issues/2
# https://github.com/ponty/PyVirtualDisplay/issues/14
self.old_display_var = os.environ.get("DISPLAY", None)
def _start1(self):
with _mutex:
self.display = _search_for_display()
while self.display in _USED_DISPLAY_NR_LIST:
self.display += 1
self.new_display_var = ":%s" % int(self.display)
_USED_DISPLAY_NR_LIST.append(self.display)
self._command = self._cmd() + self._extra_args
log.debug("command: %s", self._command)
self._popen(use_pass_fds=False)
self.new_display_var = ":%s" % int(self.display)
if self._use_xauth:
self._setup_xauth()
# https://github.com/ponty/PyVirtualDisplay/issues/2
# https://github.com/ponty/PyVirtualDisplay/issues/14
self.old_display_var = os.environ.get("DISPLAY", None)
# wait until X server is active
start_time = time.time()
d = self.new_display_var
ok = False
time.sleep(0.05) # give time for early exit
while True:
if not self.is_alive():
break
try:
xdpyinfo = subprocess.Popen(
["xdpyinfo"],
env=self._env(),
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
shell=False,
)
_, _ = xdpyinfo.communicate()
exit_code = xdpyinfo.returncode
except FileNotFoundError:
log.warning(
"xdpyinfo was not found, X start can not be checked! Please install xdpyinfo!"
)
time.sleep(_X_START_WAIT) # old method
ok = True
break
# try:
# xdpyinfo = EasyProcess(["xdpyinfo"], env=self._env())
# xdpyinfo.enable_stdout_log = False
# xdpyinfo.enable_stderr_log = False
# exit_code = xdpyinfo.call().return_code
# except EasyProcessError:
# log.warning(
# "xdpyinfo was not found, X start can not be checked! Please install xdpyinfo!"
# )
# time.sleep(_X_START_WAIT) # old method
# ok = True
# break
if exit_code != 0:
pass
else:
log.info('Successfully started X with display "%s".', d)
ok = True
break
if time.time() - start_time >= _X_START_TIMEOUT:
break
time.sleep(_X_START_TIME_STEP)
if not self.is_alive():
log.warning("process exited early. stderr:%s", self.stderr)
msg = "Failed to start process: %s"
raise XStartError(msg % self)
if not ok:
msg = 'Failed to start X on display "%s" (xdpyinfo check failed, stderr:[%s]).'
raise XStartTimeoutError(msg % (d, xdpyinfo.stderr))
def _wait_for_pipe_text(self, rfd):
s = ""
start_time = time.time()
while True:
(rfd_changed_ls, _, _) = select.select([rfd], [], [], 0.1)
if not self.is_alive():
raise XStartError(
"%s program closed. command: %s stderr: %s"
% (self._program, self._command, self.stderr)
)
if rfd in rfd_changed_ls:
c = os.read(rfd, 1)
if c == b"\n":
break
s += c.decode("ascii")
# this timeout is for "eternal" hang. see #62
if time.time() - start_time >= 600: # = 10 minutes
raise XStartTimeoutError(
"No reply from program %s. command:%s"
% (
self._program,
self._command,
)
)
return s
def stop(self):
"""
stop display
:rtype: self
"""
if not self._is_started:
raise XStartError("stop() is called before start().")
if self._reset_global_env:
self._redirect_display(False)
if self.is_alive():
try:
self._subproc.kill()
except OSError as oserror:
log.debug("exception in terminate:%s", oserror)
self._subproc.wait()
self._read_stdout_stderr()
if self._use_xauth:
self._clear_xauth()
return self
def _read_stdout_stderr(self):
if self.stdout is None:
(self.stdout, self.stderr) = self._subproc.communicate()
log.debug("stdout=%s", self.stdout)
log.debug("stderr=%s", self.stderr)
def _setup_xauth(self):
"""
Set up the Xauthority file and the XAUTHORITY environment variable.
"""
handle, filename = tempfile.mkstemp(
prefix="PyVirtualDisplay.", suffix=".Xauthority"
)
self._xauth_filename = filename
os.close(handle)
# Save old environment
self._old_xauth = {}
self._old_xauth["AUTHFILE"] = os.getenv("AUTHFILE")
self._old_xauth["XAUTHORITY"] = os.getenv("XAUTHORITY")
os.environ["AUTHFILE"] = os.environ["XAUTHORITY"] = filename
cookie = xauth.generate_mcookie()
xauth.call("add", self.new_display_var, ".", cookie)
def _clear_xauth(self):
"""
Clear the Xauthority file and restore the environment variables.
"""
os.remove(self._xauth_filename)
for varname in ["AUTHFILE", "XAUTHORITY"]:
if self._old_xauth[varname] is None:
del os.environ[varname]
else:
os.environ[varname] = self._old_xauth[varname]
self._old_xauth = None
def __enter__(self):
"""used by the :keyword:`with` statement"""
self.start()
return self
def __exit__(self, *exc_info):
"""used by the :keyword:`with` statement"""
self.stop()
def is_alive(self):
if not self._subproc:
return False
# return self.return_code is None
rc = self._subproc.poll()
if rc is not None:
# proc exited
self._read_stdout_stderr()
return rc is None
# @property
# def return_code(self):
# if not self._subproc:
# return None
# rc = self._subproc.poll()
# if rc is not None:
# # proc exited
# self._read_stdout_stderr()
# return rc
@property
def pid(self):
"""
PID (:attr:`subprocess.Popen.pid`)
:rtype: int
"""
if self._subproc:
return self._subproc.pid
Zerion Mini Shell 1.0