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| Dir : //proc/self/root/opt/saltstack/salt/lib/python3.10/site-packages/salt/utils/vt.py |
"""
:codeauthor: Pedro Algarvio (pedro@algarvio.me)
salt.utils.vt
~~~~~~~~~~~~~
Virtual Terminal
This code has been heavily inspired by Python's subprocess code, the `non
blocking version of it`__, some minor online snippets about TTY handling
with python including `Python's own ``pty`` source code`__ and `Pexpect`__
which has already surpassed some of the pitfalls that some systems would
get us into.
.. __: http://code.activestate.com/recipes/440554/
.. __: https://github.com/python/cpython/blob/3.3/Lib/pty.py
.. __: https://github.com/pexpect/pexpect
"""
import errno
import functools
import logging
import os
import select
import signal
import subprocess
import sys
import time
import salt.utils.crypt
import salt.utils.data
import salt.utils.stringutils
from salt._logging import LOG_LEVELS
mswindows = sys.platform == "win32"
try:
# pylint: disable=F0401,W0611
import msvcrt
import win32api
import win32con
import win32process
from win32file import ReadFile, WriteFile
from win32pipe import PeekNamedPipe
# pylint: enable=F0401,W0611
except ImportError:
import fcntl
import pty
import struct
import termios
log = logging.getLogger(__name__)
class TerminalException(Exception):
"""
Terminal specific exception
"""
def setwinsize(child, rows=80, cols=80):
"""
This sets the terminal window size of the child tty. This will
cause a SIGWINCH signal to be sent to the child. This does not
change the physical window size. It changes the size reported to
TTY-aware applications like vi or curses -- applications that
respond to the SIGWINCH signal.
Thank you for the shortcut PEXPECT
"""
# pylint: disable=used-before-assignment
TIOCSWINSZ = getattr(termios, "TIOCSWINSZ", -2146929561)
if TIOCSWINSZ == 2148037735:
# Same bits, but with sign.
TIOCSWINSZ = -2146929561
# Note, assume ws_xpixel and ws_ypixel are zero.
packed = struct.pack(b"HHHH", rows, cols, 0, 0)
fcntl.ioctl(child, TIOCSWINSZ, packed)
def getwinsize(child):
"""
This returns the terminal window size of the child tty. The return
value is a tuple of (rows, cols).
Thank you for the shortcut PEXPECT
"""
TIOCGWINSZ = getattr(termios, "TIOCGWINSZ", 1074295912)
packed = struct.pack(b"HHHH", 0, 0, 0, 0)
ioctl = fcntl.ioctl(child, TIOCGWINSZ, packed)
return struct.unpack(b"HHHH", ioctl)[0:2]
class Terminal:
"""
I'm a virtual terminal
"""
def __init__(
self,
args=None,
executable=None,
shell=False,
cwd=None,
env=None,
preexec_fn=None,
# Terminal Size
rows=None,
cols=None,
# Logging options
log_stdin=None,
log_stdin_level="debug",
log_stdout=None,
log_stdout_level="debug",
log_stderr=None,
log_stderr_level="debug",
log_sanitize=None,
# sys.stdXYZ streaming options
stream_stdout=None,
stream_stderr=None,
# Used for tests
force_receive_encoding=__salt_system_encoding__,
):
if not args and not executable:
raise TerminalException(
'You need to pass at least one of "args", "executable" '
)
self.args = args
self.executable = executable
self.shell = shell
self.cwd = cwd
self.env = env
self.preexec_fn = preexec_fn
self.receive_encoding = force_receive_encoding
if rows is None and cols is None:
rows, cols = self.__detect_parent_terminal_size()
elif rows is not None and cols is None:
_, cols = self.__detect_parent_terminal_size()
elif rows is None and cols is not None:
rows, _ = self.__detect_parent_terminal_size()
self.rows = rows
self.cols = cols
self.pid = None
self.stdin = None
self.stdout = None
self.stderr = None
self.child_fd = None
self.child_fde = None
self.partial_data_stdout = b""
self.partial_data_stderr = b""
self.closed = True
self.flag_eof_stdout = False
self.flag_eof_stderr = False
self.terminated = True
self.exitstatus = None
self.signalstatus = None
# status returned by os.waitpid
self.status = None
if stream_stdout is True:
self.stream_stdout = sys.stdout
elif stream_stdout is False:
self.stream_stdout = None
elif stream_stdout is not None:
if (
not hasattr(stream_stdout, "write")
or not hasattr(stream_stdout, "flush")
or not hasattr(stream_stdout, "close")
):
raise TerminalException(
"'stream_stdout' needs to have at least 3 methods, "
"'write()', 'flush()' and 'close()'."
)
self.stream_stdout = stream_stdout
else:
raise TerminalException(
"Don't know how to handle '{}' as the VT's "
"'stream_stdout' parameter.".format(stream_stdout)
)
if stream_stderr is True:
self.stream_stderr = sys.stderr
elif stream_stderr is False:
self.stream_stderr = None
elif stream_stderr is not None:
if (
not hasattr(stream_stderr, "write")
or not hasattr(stream_stderr, "flush")
or not hasattr(stream_stderr, "close")
):
raise TerminalException(
"'stream_stderr' needs to have at least 3 methods, "
"'write()', 'flush()' and 'close()'."
)
self.stream_stderr = stream_stderr
else:
raise TerminalException(
"Don't know how to handle '{}' as the VT's "
"'stream_stderr' parameter.".format(stream_stderr)
)
try:
self._spawn()
except Exception as err: # pylint: disable=W0703
# A lot can go wrong, so that's why we're catching the most general
# exception type
log.warning(
"Failed to spawn the VT: %s", err, exc_info_on_loglevel=logging.DEBUG
)
raise TerminalException(f"Failed to spawn the VT. Error: {err}")
log.debug(
"Child Forked! PID: %s STDOUT_FD: %s STDERR_FD: %s",
self.pid,
self.child_fd,
self.child_fde,
)
if log_sanitize:
if not isinstance(log_sanitize, str):
raise RuntimeError("'log_sanitize' needs to be a str type")
self.log_sanitize = log_sanitize
else:
self.log_sanitize = None
terminal_command = " ".join(self.args)
if self.log_sanitize:
terminal_command = terminal_command.replace(self.log_sanitize, ("*" * 6))
if (
'decode("base64")' in terminal_command
or "base64.b64decode(" in terminal_command
):
log.debug("VT: Salt-SSH SHIM Terminal Command executed. Logged to TRACE")
log.trace("Terminal Command: %s", terminal_command)
else:
log.debug("Terminal Command: %s", terminal_command)
# Setup logging after spawned in order to have a pid value
self.stdin_logger_level = LOG_LEVELS.get(log_stdin_level, log_stdin_level)
if log_stdin is True:
self.stdin_logger = logging.getLogger(
f"{__name__}.{self.__class__.__name__}.PID-{self.pid}.STDIN"
)
elif log_stdin is not None:
if not isinstance(log_stdin, logging.Logger):
raise RuntimeError("'log_stdin' needs to subclass `logging.Logger`")
self.stdin_logger = log_stdin
else:
self.stdin_logger = None
self.stdout_logger_level = LOG_LEVELS.get(log_stdout_level, log_stdout_level)
if log_stdout is True:
self.stdout_logger = logging.getLogger(
"{}.{}.PID-{}.STDOUT".format(
__name__, self.__class__.__name__, self.pid
)
)
elif log_stdout is not None:
if not isinstance(log_stdout, logging.Logger):
raise RuntimeError("'log_stdout' needs to subclass `logging.Logger`")
self.stdout_logger = log_stdout
else:
self.stdout_logger = None
self.stderr_logger_level = LOG_LEVELS.get(log_stderr_level, log_stderr_level)
if log_stderr is True:
self.stderr_logger = logging.getLogger(
"{}.{}.PID-{}.STDERR".format(
__name__, self.__class__.__name__, self.pid
)
)
elif log_stderr is not None:
if not isinstance(log_stderr, logging.Logger):
raise RuntimeError("'log_stderr' needs to subclass `logging.Logger`")
self.stderr_logger = log_stderr
else:
self.stderr_logger = None
def send(self, data):
"""
Send data to the terminal. You are responsible to send any required
line feeds.
"""
return self._send(data)
def sendline(self, data, linesep=os.linesep):
"""
Send the provided data to the terminal appending a line feed.
"""
return self.send(f"{data}{linesep}")
def recv(self, maxsize=None):
"""
Receive data from the terminal as a (``stdout``, ``stderr``) tuple. If
any of those is ``None`` we can no longer communicate with the
terminal's child process.
"""
if maxsize is None:
maxsize = 1024
elif maxsize < 1:
maxsize = 1
return self._recv(maxsize)
def close(self, terminate=True, kill=False):
"""
Close the communication with the terminal's child.
If ``terminate`` is ``True`` then additionally try to terminate the
terminal, and if ``kill`` is also ``True``, kill the terminal if
terminating it was not enough.
"""
if not self.closed:
if self.child_fd is not None:
os.close(self.child_fd)
self.child_fd = None
if self.child_fde is not None:
os.close(self.child_fde)
self.child_fde = None
time.sleep(0.1)
if terminate:
if not self.terminate(kill):
raise TerminalException("Failed to terminate child process.")
self.closed = True
@property
def has_unread_data(self):
return self.flag_eof_stderr is False or self.flag_eof_stdout is False
def _translate_newlines(self, data):
if data is None or not data:
return
# PTY's always return \r\n as the line feeds
return data.replace("\r\n", os.linesep)
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, traceback):
self.close(terminate=True, kill=True)
# Wait for the process to terminate, to avoid zombies.
if self.isalive():
self.wait()
if mswindows:
def _execute(self):
raise NotImplementedError
def _spawn(self):
raise NotImplementedError
def _recv(self, maxsize):
raise NotImplementedError
def _send(self, data):
raise NotImplementedError
def send_signal(self, sig):
"""
Send a signal to the process
"""
# pylint: disable=E1101
if sig == signal.SIGTERM:
self.terminate()
elif sig == signal.CTRL_C_EVENT:
os.kill(self.pid, signal.CTRL_C_EVENT)
elif sig == signal.CTRL_BREAK_EVENT:
os.kill(self.pid, signal.CTRL_BREAK_EVENT)
else:
raise ValueError(f"Unsupported signal: {sig}")
# pylint: enable=E1101
def terminate(self, force=False):
"""
Terminates the process
"""
try:
win32api.TerminateProcess(self._handle, 1)
except OSError:
# ERROR_ACCESS_DENIED (winerror 5) is received when the
# process already died.
ecode = win32process.GetExitCodeProcess(self._handle)
if ecode == win32con.STILL_ACTIVE:
raise
self.exitstatus = ecode
kill = terminate
else:
def _spawn(self):
if not isinstance(self.args, str) and self.shell is True:
self.args = " ".join(self.args)
parent, child = pty.openpty() # pylint: disable=used-before-assignment
err_parent, err_child = os.pipe()
child_name = os.ttyname(child)
proc = subprocess.Popen( # pylint: disable=subprocess-popen-preexec-fn
self.args,
preexec_fn=functools.partial(
self._preexec, child_name, self.rows, self.cols, self.preexec_fn
),
shell=self.shell, # nosec
executable=self.executable,
cwd=self.cwd,
stdin=child,
stdout=child,
stderr=err_child,
env=self.env,
close_fds=True,
)
os.close(child)
os.close(err_child)
self.child_fd = parent
self.child_fde = err_parent
self.pid = proc.pid
self.proc = proc
self.closed = False
self.terminated = False
@staticmethod
def _preexec(child_name, rows=80, cols=80, preexec_fn=None):
# Disconnect from controlling tty. Harmless if not already
# connected
try:
tty_fd = os.open("/dev/tty", os.O_RDWR | os.O_NOCTTY)
if tty_fd >= 0:
os.close(tty_fd)
# which exception, shouldn't we catch explicitly .. ?
except Exception: # pylint: disable=broad-except
# Already disconnected. This happens if running inside cron
pass
try:
os.setsid()
except OSError:
pass
try:
tty_fd = os.open("/dev/tty", os.O_RDWR | os.O_NOCTTY)
if tty_fd >= 0:
os.close(tty_fd)
raise TerminalException(f"Could not open child pty, {child_name}")
# which exception, shouldn't we catch explicitly .. ?
except Exception: # pylint: disable=broad-except
# Good! We are disconnected from a controlling tty.
pass
tty_fd = os.open(child_name, os.O_RDWR)
setwinsize(tty_fd, rows, cols)
if tty_fd < 0:
raise TerminalException(f"Could not open child pty, {child_name}")
else:
os.close(tty_fd)
if os.name != "posix":
tty_fd = os.open("/dev/tty", os.O_WRONLY)
if tty_fd < 0:
raise TerminalException("Could not open controlling tty, /dev/tty")
else:
os.close(tty_fd)
salt.utils.crypt.reinit_crypto()
if preexec_fn is not None:
preexec_fn()
def _send(self, data):
if self.child_fd is None:
return None
if not select.select([], [self.child_fd], [], 0)[1]:
return 0
try:
if self.stdin_logger:
self.stdin_logger.log(self.stdin_logger_level, data)
written = os.write(self.child_fd, data.encode(__salt_system_encoding__))
except OSError as why:
if why.errno == errno.EPIPE: # broken pipe
os.close(self.child_fd)
self.child_fd = None
return
raise
return written
def _recv(self, maxsize):
rfds = []
if self.child_fd:
rfds.append(self.child_fd)
if self.child_fde:
rfds.append(self.child_fde)
if not self.isalive():
if not rfds:
self.close()
return None, None
rlist, _, _ = select.select(rfds, [], [], 0)
if not rlist:
self.flag_eof_stdout = self.flag_eof_stderr = True
log.debug("End of file(EOL). Brain-dead platform.")
if self.partial_data_stdout or self.partial_data_stderr:
# There is data that was received but for which
# decoding failed, attempt decoding again to generate
# relevant exception
self.close()
return (
salt.utils.stringutils.to_unicode(self.partial_data_stdout),
salt.utils.stringutils.to_unicode(self.partial_data_stderr),
)
self.close()
return None, None
stderr = ""
stdout = ""
if self.child_fd:
fd_flags = fcntl.fcntl(self.child_fd, fcntl.F_GETFL)
if self.child_fde:
fde_flags = fcntl.fcntl(self.child_fde, fcntl.F_GETFL)
if self.child_fd:
fcntl.fcntl(self.child_fd, fcntl.F_SETFL, fd_flags | os.O_NONBLOCK)
if self.child_fde:
fcntl.fcntl(self.child_fde, fcntl.F_SETFL, fde_flags | os.O_NONBLOCK)
rlist, _, _ = select.select(rfds, [], [], 0)
if not rlist:
if not self.isalive():
self.flag_eof_stdout = self.flag_eof_stderr = True
log.debug("End of file(EOL). Very slow platform.")
return None, None
def read_and_decode_fd(fd, maxsize, partial_data_attr=None):
bytes_read = getattr(self, partial_data_attr, b"")
# Only read one byte if we already have some existing data
# to try and complete a split multibyte character
bytes_read += os.read(fd, maxsize if not bytes_read else 1)
try:
decoded_data = self._translate_newlines(
salt.utils.stringutils.to_unicode(
bytes_read, self.receive_encoding
)
)
if partial_data_attr is not None:
setattr(self, partial_data_attr, b"")
return decoded_data, False
except UnicodeDecodeError as ex:
max_multibyte_character_length = 4
if ex.start > (
len(bytes_read) - max_multibyte_character_length
) and ex.end == len(bytes_read):
# We weren't able to decode the received data possibly
# because it is a multibyte character split across
# blocks. Save what data we have to try and decode
# later. If the error wasn't caused by a multibyte
# character being split then the error start position
# should remain the same each time we get here but the
# length of the bytes_read will increase so we will
# give up and raise an exception instead.
if partial_data_attr is not None:
setattr(self, partial_data_attr, bytes_read)
else:
# We haven't been given anywhere to store partial
# data so raise the exception instead
raise
# No decoded data to return, but indicate that there
# is buffered data
return "", True
else:
raise
if self.child_fde in rlist and not self.flag_eof_stderr:
try:
stderr, partial_data = read_and_decode_fd(
self.child_fde, maxsize, "partial_data_stderr"
)
if not stderr and not partial_data:
self.flag_eof_stderr = True
stderr = None
else:
if self.stream_stderr:
self.stream_stderr.write(stderr)
self.stream_stderr.flush()
if self.stderr_logger:
stripped = stderr.rstrip()
if self.log_sanitize:
stripped = stripped.replace(
self.log_sanitize, ("*" * 6)
)
if stripped.startswith(os.linesep):
stripped = stripped[len(os.linesep) :]
if stripped:
self.stderr_logger.log(
self.stderr_logger_level, stripped
)
except OSError:
os.close(self.child_fde)
self.child_fde = None
self.flag_eof_stderr = True
stderr = None
finally:
if self.child_fde is not None:
fcntl.fcntl(self.child_fde, fcntl.F_SETFL, fde_flags)
if self.child_fd in rlist and not self.flag_eof_stdout:
try:
stdout, partial_data = read_and_decode_fd(
self.child_fd, maxsize, "partial_data_stdout"
)
if not stdout and not partial_data:
self.flag_eof_stdout = True
stdout = None
else:
if self.stream_stdout:
self.stream_stdout.write(
salt.utils.stringutils.to_str(stdout)
)
self.stream_stdout.flush()
if self.stdout_logger:
stripped = stdout.rstrip()
if self.log_sanitize:
stripped = stripped.replace(
self.log_sanitize, ("*" * 6)
)
if stripped.startswith(os.linesep):
stripped = stripped[len(os.linesep) :]
if stripped:
self.stdout_logger.log(
self.stdout_logger_level, stripped
)
except OSError:
os.close(self.child_fd)
self.child_fd = None
self.flag_eof_stdout = True
stdout = None
finally:
if self.child_fd is not None:
fcntl.fcntl(self.child_fd, fcntl.F_SETFL, fd_flags)
# <---- Process STDOUT -------------------------------------------
return stdout, stderr
def __detect_parent_terminal_size(self):
try:
TIOCGWINSZ = getattr(termios, "TIOCGWINSZ", 1074295912)
packed = struct.pack(b"HHHH", 0, 0, 0, 0)
ioctl = fcntl.ioctl(sys.stdin.fileno(), TIOCGWINSZ, packed)
return struct.unpack(b"HHHH", ioctl)[0:2]
except OSError:
# Return a default value of 24x80
return 24, 80
# <---- Internal API -------------------------------------------------
# ----- Public API -------------------------------------------------->
def getwinsize(self):
"""
This returns the terminal window size of the child tty. The return
value is a tuple of (rows, cols).
Thank you for the shortcut PEXPECT
"""
if self.child_fd is None:
raise TerminalException(
"Can't check the size of the terminal since we're not "
"connected to the child process."
)
return getwinsize(self.child_fd)
def setwinsize(self, child, rows=80, cols=80):
setwinsize(self.child_fd, rows, cols)
def isalive(
self,
_waitpid=os.waitpid,
_wnohang=os.WNOHANG,
_wifexited=os.WIFEXITED,
_wexitstatus=os.WEXITSTATUS,
_wifsignaled=os.WIFSIGNALED,
_wifstopped=os.WIFSTOPPED,
_wtermsig=os.WTERMSIG,
_os_error=os.error,
_errno_echild=errno.ECHILD,
_terminal_exception=TerminalException,
):
"""
This tests if the child process is running or not. This is
non-blocking. If the child was terminated then this will read the
exitstatus or signalstatus of the child. This returns True if the
child process appears to be running or False if not. It can take
literally SECONDS for Solaris to return the right status.
"""
if self.terminated:
return False
if self.has_unread_data is False:
# This is for Linux, which requires the blocking form
# of waitpid to get status of a defunct process.
# This is super-lame. The flag_eof_* would have been set
# in recv(), so this should be safe.
waitpid_options = 0
else:
waitpid_options = _wnohang
try:
pid, status = _waitpid(self.pid, waitpid_options)
except ChildProcessError:
# check if process is really dead or if it is just pretending and we should exit normally through the gift center
polled = self.proc.poll()
if polled is None:
return True
# process must have returned on it's own process the return code
pid = self.pid
status = polled
except _os_error:
err = sys.exc_info()[1]
# No child processes
if err.errno == _errno_echild:
raise _terminal_exception(
'isalive() encountered condition where "terminated" '
"is 0, but there was no child process. Did someone "
"else call waitpid() on our process?"
)
else:
raise
# I have to do this twice for Solaris.
# I can't even believe that I figured this out...
# If waitpid() returns 0 it means that no child process
# wishes to report, and the value of status is undefined.
if pid == 0:
try:
### os.WNOHANG # Solaris!
pid, status = _waitpid(self.pid, waitpid_options)
except _os_error as exc:
# This should never happen...
if exc.errno == _errno_echild:
raise _terminal_exception(
"isalive() encountered condition that should "
"never happen. There was no child process. Did "
"someone else call waitpid() on our process?"
)
else:
raise
# If pid is still 0 after two calls to waitpid() then the
# process really is alive. This seems to work on all platforms,
# except for Irix which seems to require a blocking call on
# waitpid or select, so I let recv take care of this situation
# (unfortunately, this requires waiting through the timeout).
if pid == 0:
return True
if pid == 0:
return True
if _wifexited(status):
self.status = status
self.exitstatus = _wexitstatus(status)
self.signalstatus = None
self.terminated = True
elif _wifsignaled(status):
self.status = status
self.exitstatus = None
self.signalstatus = _wtermsig(status)
self.terminated = True
elif _wifstopped(status):
raise _terminal_exception(
"isalive() encountered condition where child process is "
"stopped. This is not supported. Is some other process "
"attempting job control with our child pid?"
)
return False
def terminate(self, force=False):
"""
This forces a child process to terminate. It starts nicely with
SIGHUP and SIGINT. If "force" is True then moves onto SIGKILL. This
returns True if the child was terminated. This returns False if the
child could not be terminated.
"""
if not self.closed:
self.close(terminate=False)
if not self.isalive():
return True
try:
self.send_signal(signal.SIGHUP)
time.sleep(0.1)
if not self.isalive():
return True
self.send_signal(signal.SIGCONT)
time.sleep(0.1)
if not self.isalive():
return True
self.send_signal(signal.SIGINT)
time.sleep(0.1)
if not self.isalive():
return True
if force:
self.send_signal(signal.SIGKILL)
time.sleep(0.1)
if not self.isalive():
return True
else:
return False
return False
except OSError:
# I think there are kernel timing issues that sometimes cause
# this to happen. I think isalive() reports True, but the
# process is dead to the kernel.
# Make one last attempt to see if the kernel is up to date.
time.sleep(0.1)
if not self.isalive():
return True
else:
return False
def wait(self):
"""
This waits until the child exits internally consuming any remaining
output from the child, thus, no blocking forever because the child
has unread data.
"""
if self.isalive():
while self.isalive():
stdout, stderr = self.recv()
if stdout is None:
break
if stderr is None:
break
else:
raise TerminalException("Cannot wait for dead child process.")
return self.exitstatus
def send_signal(self, sig):
"""
Send a signal to the process
"""
os.kill(self.pid, sig)
def kill(self):
"""
Kill the process with SIGKILL
"""
self.send_signal(signal.SIGKILL)