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_process_win32_controller.py
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/ IPython / utils / _process_win32_controller.py
"""Windows-specific implementation of process utilities with direct WinAPI.
This file is meant to be used by process.py
"""
#-----------------------------------------------------------------------------
# Copyright (C) 2010-2011 The IPython Development Team
#
# Distributed under the terms of the BSD License. The full license is in
# the file COPYING, distributed as part of this software.
#-----------------------------------------------------------------------------
# stdlib
import os, sys, threading
import ctypes, msvcrt
# Win32 API types needed for the API calls
from ctypes import POINTER
from ctypes.wintypes import HANDLE, HLOCAL, LPVOID, WORD, DWORD, BOOL, \
ULONG, LPCWSTR
LPDWORD = POINTER(DWORD)
LPHANDLE = POINTER(HANDLE)
ULONG_PTR = POINTER(ULONG)
class SECURITY_ATTRIBUTES(ctypes.Structure):
_fields_ = [("nLength", DWORD),
("lpSecurityDescriptor", LPVOID),
("bInheritHandle", BOOL)]
LPSECURITY_ATTRIBUTES = POINTER(SECURITY_ATTRIBUTES)
class STARTUPINFO(ctypes.Structure):
_fields_ = [("cb", DWORD),
("lpReserved", LPCWSTR),
("lpDesktop", LPCWSTR),
("lpTitle", LPCWSTR),
("dwX", DWORD),
("dwY", DWORD),
("dwXSize", DWORD),
("dwYSize", DWORD),
("dwXCountChars", DWORD),
("dwYCountChars", DWORD),
("dwFillAttribute", DWORD),
("dwFlags", DWORD),
("wShowWindow", WORD),
("cbReserved2", WORD),
("lpReserved2", LPVOID),
("hStdInput", HANDLE),
("hStdOutput", HANDLE),
("hStdError", HANDLE)]
LPSTARTUPINFO = POINTER(STARTUPINFO)
class PROCESS_INFORMATION(ctypes.Structure):
_fields_ = [("hProcess", HANDLE),
("hThread", HANDLE),
("dwProcessId", DWORD),
("dwThreadId", DWORD)]
LPPROCESS_INFORMATION = POINTER(PROCESS_INFORMATION)
# Win32 API constants needed
ERROR_HANDLE_EOF = 38
ERROR_BROKEN_PIPE = 109
ERROR_NO_DATA = 232
HANDLE_FLAG_INHERIT = 0x0001
STARTF_USESTDHANDLES = 0x0100
CREATE_SUSPENDED = 0x0004
CREATE_NEW_CONSOLE = 0x0010
CREATE_NO_WINDOW = 0x08000000
STILL_ACTIVE = 259
WAIT_TIMEOUT = 0x0102
WAIT_FAILED = 0xFFFFFFFF
INFINITE = 0xFFFFFFFF
DUPLICATE_SAME_ACCESS = 0x00000002
ENABLE_ECHO_INPUT = 0x0004
ENABLE_LINE_INPUT = 0x0002
ENABLE_PROCESSED_INPUT = 0x0001
# Win32 API functions needed
GetLastError = ctypes.windll.kernel32.GetLastError
GetLastError.argtypes = []
GetLastError.restype = DWORD
CreateFile = ctypes.windll.kernel32.CreateFileW
CreateFile.argtypes = [LPCWSTR, DWORD, DWORD, LPVOID, DWORD, DWORD, HANDLE]
CreateFile.restype = HANDLE
CreatePipe = ctypes.windll.kernel32.CreatePipe
CreatePipe.argtypes = [POINTER(HANDLE), POINTER(HANDLE),
LPSECURITY_ATTRIBUTES, DWORD]
CreatePipe.restype = BOOL
CreateProcess = ctypes.windll.kernel32.CreateProcessW
CreateProcess.argtypes = [LPCWSTR, LPCWSTR, LPSECURITY_ATTRIBUTES,
LPSECURITY_ATTRIBUTES, BOOL, DWORD, LPVOID, LPCWSTR, LPSTARTUPINFO,
LPPROCESS_INFORMATION]
CreateProcess.restype = BOOL
GetExitCodeProcess = ctypes.windll.kernel32.GetExitCodeProcess
GetExitCodeProcess.argtypes = [HANDLE, LPDWORD]
GetExitCodeProcess.restype = BOOL
GetCurrentProcess = ctypes.windll.kernel32.GetCurrentProcess
GetCurrentProcess.argtypes = []
GetCurrentProcess.restype = HANDLE
ResumeThread = ctypes.windll.kernel32.ResumeThread
ResumeThread.argtypes = [HANDLE]
ResumeThread.restype = DWORD
ReadFile = ctypes.windll.kernel32.ReadFile
ReadFile.argtypes = [HANDLE, LPVOID, DWORD, LPDWORD, LPVOID]
ReadFile.restype = BOOL
WriteFile = ctypes.windll.kernel32.WriteFile
WriteFile.argtypes = [HANDLE, LPVOID, DWORD, LPDWORD, LPVOID]
WriteFile.restype = BOOL
GetConsoleMode = ctypes.windll.kernel32.GetConsoleMode
GetConsoleMode.argtypes = [HANDLE, LPDWORD]
GetConsoleMode.restype = BOOL
SetConsoleMode = ctypes.windll.kernel32.SetConsoleMode
SetConsoleMode.argtypes = [HANDLE, DWORD]
SetConsoleMode.restype = BOOL
FlushConsoleInputBuffer = ctypes.windll.kernel32.FlushConsoleInputBuffer
FlushConsoleInputBuffer.argtypes = [HANDLE]
FlushConsoleInputBuffer.restype = BOOL
WaitForSingleObject = ctypes.windll.kernel32.WaitForSingleObject
WaitForSingleObject.argtypes = [HANDLE, DWORD]
WaitForSingleObject.restype = DWORD
DuplicateHandle = ctypes.windll.kernel32.DuplicateHandle
DuplicateHandle.argtypes = [HANDLE, HANDLE, HANDLE, LPHANDLE,
DWORD, BOOL, DWORD]
DuplicateHandle.restype = BOOL
SetHandleInformation = ctypes.windll.kernel32.SetHandleInformation
SetHandleInformation.argtypes = [HANDLE, DWORD, DWORD]
SetHandleInformation.restype = BOOL
CloseHandle = ctypes.windll.kernel32.CloseHandle
CloseHandle.argtypes = [HANDLE]
CloseHandle.restype = BOOL
CommandLineToArgvW = ctypes.windll.shell32.CommandLineToArgvW
CommandLineToArgvW.argtypes = [LPCWSTR, POINTER(ctypes.c_int)]
CommandLineToArgvW.restype = POINTER(LPCWSTR)
LocalFree = ctypes.windll.kernel32.LocalFree
LocalFree.argtypes = [HLOCAL]
LocalFree.restype = HLOCAL
class AvoidUNCPath(object):
"""A context manager to protect command execution from UNC paths.
In the Win32 API, commands can't be invoked with the cwd being a UNC path.
This context manager temporarily changes directory to the 'C:' drive on
entering, and restores the original working directory on exit.
The context manager returns the starting working directory *if* it made a
change and None otherwise, so that users can apply the necessary adjustment
to their system calls in the event of a change.
Examples
--------
::
cmd = 'dir'
with AvoidUNCPath() as path:
if path is not None:
cmd = '"pushd %s &&"%s' % (path, cmd)
os.system(cmd)
"""
def __enter__(self):
self.path = os.getcwd()
self.is_unc_path = self.path.startswith(r"\\")
if self.is_unc_path:
# change to c drive (as cmd.exe cannot handle UNC addresses)
os.chdir("C:")
return self.path
else:
# We return None to signal that there was no change in the working
# directory
return None
def __exit__(self, exc_type, exc_value, traceback):
if self.is_unc_path:
os.chdir(self.path)
class Win32ShellCommandController(object):
"""Runs a shell command in a 'with' context.
This implementation is Win32-specific.
Example:
# Runs the command interactively with default console stdin/stdout
with ShellCommandController('python -i') as scc:
scc.run()
# Runs the command using the provided functions for stdin/stdout
def my_stdout_func(s):
# print or save the string 's'
write_to_stdout(s)
def my_stdin_func():
# If input is available, return it as a string.
if input_available():
return get_input()
# If no input available, return None after a short delay to
# keep from blocking.
else:
time.sleep(0.01)
return None
with ShellCommandController('python -i') as scc:
scc.run(my_stdout_func, my_stdin_func)
"""
def __init__(self, cmd, mergeout = True):
"""Initializes the shell command controller.
The cmd is the program to execute, and mergeout is
whether to blend stdout and stderr into one output
in stdout. Merging them together in this fashion more
reliably keeps stdout and stderr in the correct order
especially for interactive shell usage.
"""
self.cmd = cmd
self.mergeout = mergeout
def __enter__(self):
cmd = self.cmd
mergeout = self.mergeout
self.hstdout, self.hstdin, self.hstderr = None, None, None
self.piProcInfo = None
try:
p_hstdout, c_hstdout, p_hstderr, \
c_hstderr, p_hstdin, c_hstdin = [None]*6
# SECURITY_ATTRIBUTES with inherit handle set to True
saAttr = SECURITY_ATTRIBUTES()
saAttr.nLength = ctypes.sizeof(saAttr)
saAttr.bInheritHandle = True
saAttr.lpSecurityDescriptor = None
def create_pipe(uninherit):
"""Creates a Windows pipe, which consists of two handles.
The 'uninherit' parameter controls which handle is not
inherited by the child process.
"""
handles = HANDLE(), HANDLE()
if not CreatePipe(ctypes.byref(handles[0]),
ctypes.byref(handles[1]), ctypes.byref(saAttr), 0):
raise ctypes.WinError()
if not SetHandleInformation(handles[uninherit],
HANDLE_FLAG_INHERIT, 0):
raise ctypes.WinError()
return handles[0].value, handles[1].value
p_hstdout, c_hstdout = create_pipe(uninherit=0)
# 'mergeout' signals that stdout and stderr should be merged.
# We do that by using one pipe for both of them.
if mergeout:
c_hstderr = HANDLE()
if not DuplicateHandle(GetCurrentProcess(), c_hstdout,
GetCurrentProcess(), ctypes.byref(c_hstderr),
0, True, DUPLICATE_SAME_ACCESS):
raise ctypes.WinError()
else:
p_hstderr, c_hstderr = create_pipe(uninherit=0)
c_hstdin, p_hstdin = create_pipe(uninherit=1)
# Create the process object
piProcInfo = PROCESS_INFORMATION()
siStartInfo = STARTUPINFO()
siStartInfo.cb = ctypes.sizeof(siStartInfo)
siStartInfo.hStdInput = c_hstdin
siStartInfo.hStdOutput = c_hstdout
siStartInfo.hStdError = c_hstderr
siStartInfo.dwFlags = STARTF_USESTDHANDLES
dwCreationFlags = CREATE_SUSPENDED | CREATE_NO_WINDOW # | CREATE_NEW_CONSOLE
if not CreateProcess(None,
u"cmd.exe /c " + cmd,
None, None, True, dwCreationFlags,
None, None, ctypes.byref(siStartInfo),
ctypes.byref(piProcInfo)):
raise ctypes.WinError()
# Close this process's versions of the child handles
CloseHandle(c_hstdin)
c_hstdin = None
CloseHandle(c_hstdout)
c_hstdout = None
if c_hstderr is not None:
CloseHandle(c_hstderr)
c_hstderr = None
# Transfer ownership of the parent handles to the object
self.hstdin = p_hstdin
p_hstdin = None
self.hstdout = p_hstdout
p_hstdout = None
if not mergeout:
self.hstderr = p_hstderr
p_hstderr = None
self.piProcInfo = piProcInfo
finally:
if p_hstdin:
CloseHandle(p_hstdin)
if c_hstdin:
CloseHandle(c_hstdin)
if p_hstdout:
CloseHandle(p_hstdout)
if c_hstdout:
CloseHandle(c_hstdout)
if p_hstderr:
CloseHandle(p_hstderr)
if c_hstderr:
CloseHandle(c_hstderr)
return self
def _stdin_thread(self, handle, hprocess, func, stdout_func):
exitCode = DWORD()
bytesWritten = DWORD(0)
while True:
#print("stdin thread loop start")
# Get the input string (may be bytes or unicode)
data = func()
# None signals to poll whether the process has exited
if data is None:
#print("checking for process completion")
if not GetExitCodeProcess(hprocess, ctypes.byref(exitCode)):
raise ctypes.WinError()
if exitCode.value != STILL_ACTIVE:
return
# TESTING: Does zero-sized writefile help?
if not WriteFile(handle, "", 0,
ctypes.byref(bytesWritten), None):
raise ctypes.WinError()
continue
#print("\nGot str %s\n" % repr(data), file=sys.stderr)
# Encode the string to the console encoding
if isinstance(data, unicode): #FIXME: Python3
data = data.encode('utf_8')
# What we have now must be a string of bytes
if not isinstance(data, str): #FIXME: Python3
raise RuntimeError("internal stdin function string error")
# An empty string signals EOF
if len(data) == 0:
return
# In a windows console, sometimes the input is echoed,
# but sometimes not. How do we determine when to do this?
stdout_func(data)
# WriteFile may not accept all the data at once.
# Loop until everything is processed
while len(data) != 0:
#print("Calling writefile")
if not WriteFile(handle, data, len(data),
ctypes.byref(bytesWritten), None):
# This occurs at exit
if GetLastError() == ERROR_NO_DATA:
return
raise ctypes.WinError()
#print("Called writefile")
data = data[bytesWritten.value:]
def _stdout_thread(self, handle, func):
# Allocate the output buffer
data = ctypes.create_string_buffer(4096)
while True:
bytesRead = DWORD(0)
if not ReadFile(handle, data, 4096,
ctypes.byref(bytesRead), None):
le = GetLastError()
if le == ERROR_BROKEN_PIPE:
return
else:
raise ctypes.WinError()
# FIXME: Python3
s = data.value[0:bytesRead.value]
#print("\nv: %s" % repr(s), file=sys.stderr)
func(s.decode('utf_8', 'replace'))
def run(self, stdout_func = None, stdin_func = None, stderr_func = None):
"""Runs the process, using the provided functions for I/O.
The function stdin_func should return strings whenever a
character or characters become available.
The functions stdout_func and stderr_func are called whenever
something is printed to stdout or stderr, respectively.
These functions are called from different threads (but not
concurrently, because of the GIL).
"""
if stdout_func is None and stdin_func is None and stderr_func is None:
return self._run_stdio()
if stderr_func is not None and self.mergeout:
raise RuntimeError("Shell command was initiated with "
"merged stdin/stdout, but a separate stderr_func "
"was provided to the run() method")
# Create a thread for each input/output handle
stdin_thread = None
threads = []
if stdin_func:
stdin_thread = threading.Thread(target=self._stdin_thread,
args=(self.hstdin, self.piProcInfo.hProcess,
stdin_func, stdout_func))
threads.append(threading.Thread(target=self._stdout_thread,
args=(self.hstdout, stdout_func)))
if not self.mergeout:
if stderr_func is None:
stderr_func = stdout_func
threads.append(threading.Thread(target=self._stdout_thread,
args=(self.hstderr, stderr_func)))
# Start the I/O threads and the process
if ResumeThread(self.piProcInfo.hThread) == 0xFFFFFFFF:
raise ctypes.WinError()
if stdin_thread is not None:
stdin_thread.start()
for thread in threads:
thread.start()
# Wait for the process to complete
if WaitForSingleObject(self.piProcInfo.hProcess, INFINITE) == \
WAIT_FAILED:
raise ctypes.WinError()
# Wait for the I/O threads to complete
for thread in threads:
thread.join()
# Wait for the stdin thread to complete
if stdin_thread is not None:
stdin_thread.join()
def _stdin_raw_nonblock(self):
"""Use the raw Win32 handle of sys.stdin to do non-blocking reads"""
# WARNING: This is experimental, and produces inconsistent results.
# It's possible for the handle not to be appropriate for use
# with WaitForSingleObject, among other things.
handle = msvcrt.get_osfhandle(sys.stdin.fileno())
result = WaitForSingleObject(handle, 100)
if result == WAIT_FAILED:
raise ctypes.WinError()
elif result == WAIT_TIMEOUT:
print(".", end='')
return None
else:
data = ctypes.create_string_buffer(256)
bytesRead = DWORD(0)
print('?', end='')
if not ReadFile(handle, data, 256,
ctypes.byref(bytesRead), None):
raise ctypes.WinError()
# This ensures the non-blocking works with an actual console
# Not checking the error, so the processing will still work with
# other handle types
FlushConsoleInputBuffer(handle)
data = data.value
data = data.replace('\r\n', '\n')
data = data.replace('\r', '\n')
print(repr(data) + " ", end='')
return data
def _stdin_raw_block(self):
"""Use a blocking stdin read"""
# The big problem with the blocking read is that it doesn't
# exit when it's supposed to in all contexts. An extra
# key-press may be required to trigger the exit.
try:
data = sys.stdin.read(1)
data = data.replace('\r', '\n')
return data
except WindowsError as we:
if we.winerror == ERROR_NO_DATA:
# This error occurs when the pipe is closed
return None
else:
# Otherwise let the error propagate
raise we
def _stdout_raw(self, s):
"""Writes the string to stdout"""
print(s, end='', file=sys.stdout)
sys.stdout.flush()
def _stderr_raw(self, s):
"""Writes the string to stdout"""
print(s, end='', file=sys.stderr)
sys.stderr.flush()
def _run_stdio(self):
"""Runs the process using the system standard I/O.
IMPORTANT: stdin needs to be asynchronous, so the Python
sys.stdin object is not used. Instead,
msvcrt.kbhit/getwch are used asynchronously.
"""
# Disable Line and Echo mode
#lpMode = DWORD()
#handle = msvcrt.get_osfhandle(sys.stdin.fileno())
#if GetConsoleMode(handle, ctypes.byref(lpMode)):
# set_console_mode = True
# if not SetConsoleMode(handle, lpMode.value &
# ~(ENABLE_ECHO_INPUT | ENABLE_LINE_INPUT | ENABLE_PROCESSED_INPUT)):
# raise ctypes.WinError()
if self.mergeout:
return self.run(stdout_func = self._stdout_raw,
stdin_func = self._stdin_raw_block)
else:
return self.run(stdout_func = self._stdout_raw,
stdin_func = self._stdin_raw_block,
stderr_func = self._stderr_raw)
# Restore the previous console mode
#if set_console_mode:
# if not SetConsoleMode(handle, lpMode.value):
# raise ctypes.WinError()
def __exit__(self, exc_type, exc_value, traceback):
if self.hstdin:
CloseHandle(self.hstdin)
self.hstdin = None
if self.hstdout:
CloseHandle(self.hstdout)
self.hstdout = None
if self.hstderr:
CloseHandle(self.hstderr)
self.hstderr = None
if self.piProcInfo is not None:
CloseHandle(self.piProcInfo.hProcess)
CloseHandle(self.piProcInfo.hThread)
self.piProcInfo = None
def system(cmd):
"""Win32 version of os.system() that works with network shares.
Note that this implementation returns None, as meant for use in IPython.
Parameters
----------
cmd : str
A command to be executed in the system shell.
Returns
-------
None : we explicitly do NOT return the subprocess status code, as this
utility is meant to be used extensively in IPython, where any return value
would trigger :func:`sys.displayhook` calls.
"""
with AvoidUNCPath() as path:
if path is not None:
cmd = '"pushd %s &&"%s' % (path, cmd)
with Win32ShellCommandController(cmd) as scc:
scc.run()
if __name__ == "__main__":
print("Test starting!")
#system("cmd")
system("python -i")
print("Test finished!")