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1 """Windows-specific implementation of process utilities.
1 """Windows-specific implementation of process utilities.
2
2
3 This file is only meant to be imported by process.py, not by end-users.
3 This file is only meant to be imported by process.py, not by end-users.
4 """
4 """
5
5 import ctypes
6 import ctypes
6 import os
7 import os
7 import subprocess
8 import subprocess
8 import sys
9 import sys
9 import time
10 import time
10 from ctypes import POINTER, c_int
11 from ctypes import POINTER, c_int
11 from ctypes.wintypes import HLOCAL, LPCWSTR
12 from ctypes.wintypes import HLOCAL, LPCWSTR
12 from subprocess import STDOUT
13 from subprocess import STDOUT
13 from threading import Thread
14 from threading import Thread
14 from types import TracebackType
15 from types import TracebackType
15 from typing import List, Optional
16 from typing import List, Optional
16
17
17 from . import py3compat
18 from . import py3compat
18 from ._process_common import arg_split as py_arg_split
19 from ._process_common import arg_split as py_arg_split
19
20
20 from ._process_common import process_handler, read_no_interrupt
21 from ._process_common import process_handler, read_no_interrupt
21 from .encoding import DEFAULT_ENCODING
22 from .encoding import DEFAULT_ENCODING
22
23
23
24
24
25 class AvoidUNCPath:
25 class AvoidUNCPath:
26 """A context manager to protect command execution from UNC paths.
26 """A context manager to protect command execution from UNC paths.
27
27
28 In the Win32 API, commands can't be invoked with the cwd being a UNC path.
28 In the Win32 API, commands can't be invoked with the cwd being a UNC path.
29 This context manager temporarily changes directory to the 'C:' drive on
29 This context manager temporarily changes directory to the 'C:' drive on
30 entering, and restores the original working directory on exit.
30 entering, and restores the original working directory on exit.
31
31
32 The context manager returns the starting working directory *if* it made a
32 The context manager returns the starting working directory *if* it made a
33 change and None otherwise, so that users can apply the necessary adjustment
33 change and None otherwise, so that users can apply the necessary adjustment
34 to their system calls in the event of a change.
34 to their system calls in the event of a change.
35
35
36 Examples
36 Examples
37 --------
37 --------
38 ::
38 ::
39 cmd = 'dir'
39 cmd = 'dir'
40 with AvoidUNCPath() as path:
40 with AvoidUNCPath() as path:
41 if path is not None:
41 if path is not None:
42 cmd = '"pushd %s &&"%s' % (path, cmd)
42 cmd = '"pushd %s &&"%s' % (path, cmd)
43 os.system(cmd)
43 os.system(cmd)
44 """
44 """
45
45
46 def __enter__(self) -> Optional[str]:
46 def __enter__(self) -> Optional[str]:
47 self.path = os.getcwd()
47 self.path = os.getcwd()
48 self.is_unc_path = self.path.startswith(r"\\")
48 self.is_unc_path = self.path.startswith(r"\\")
49 if self.is_unc_path:
49 if self.is_unc_path:
50 # change to c drive (as cmd.exe cannot handle UNC addresses)
50 # change to c drive (as cmd.exe cannot handle UNC addresses)
51 os.chdir("C:")
51 os.chdir("C:")
52 return self.path
52 return self.path
53 else:
53 else:
54 # We return None to signal that there was no change in the working
54 # We return None to signal that there was no change in the working
55 # directory
55 # directory
56 return None
56 return None
57
57
58 def __exit__(
58 def __exit__(
59 self,
59 self,
60 exc_type: Optional[type[BaseException]],
60 exc_type: Optional[type[BaseException]],
61 exc_value: Optional[BaseException],
61 exc_value: Optional[BaseException],
62 traceback: TracebackType,
62 traceback: TracebackType,
63 ) -> None:
63 ) -> None:
64 if self.is_unc_path:
64 if self.is_unc_path:
65 os.chdir(self.path)
65 os.chdir(self.path)
66
66
67
67
68 def _system_body(p: subprocess.Popen) -> int:
68 def _system_body(p: subprocess.Popen) -> int:
69 """Callback for _system."""
69 """Callback for _system."""
70 enc = DEFAULT_ENCODING
70 enc = DEFAULT_ENCODING
71
71
72 # Dec 2024: in both of these functions, I'm not sure why we .splitlines()
72 # Dec 2024: in both of these functions, I'm not sure why we .splitlines()
73 # the bytes and then decode each line individually instead of just decoding
73 # the bytes and then decode each line individually instead of just decoding
74 # the whole thing at once.
74 # the whole thing at once.
75 def stdout_read() -> None:
75 def stdout_read() -> None:
76 try:
76 try:
77 assert p.stdout is not None
77 assert p.stdout is not None
78 for byte_line in read_no_interrupt(p.stdout).splitlines():
78 for byte_line in read_no_interrupt(p.stdout).splitlines():
79 line = byte_line.decode(enc, "replace")
79 line = byte_line.decode(enc, "replace")
80 print(line, file=sys.stdout)
80 print(line, file=sys.stdout)
81 except Exception as e:
81 except Exception as e:
82 print(f"Error reading stdout: {e}", file=sys.stderr)
82 print(f"Error reading stdout: {e}", file=sys.stderr)
83
83
84 def stderr_read() -> None:
84 def stderr_read() -> None:
85 try:
85 try:
86 assert p.stderr is not None
86 assert p.stderr is not None
87 for byte_line in read_no_interrupt(p.stderr).splitlines():
87 for byte_line in read_no_interrupt(p.stderr).splitlines():
88 line = byte_line.decode(enc, "replace")
88 line = byte_line.decode(enc, "replace")
89 print(line, file=sys.stderr)
89 print(line, file=sys.stderr)
90 except Exception as e:
90 except Exception as e:
91 print(f"Error reading stderr: {e}", file=sys.stderr)
91 print(f"Error reading stderr: {e}", file=sys.stderr)
92
92
93 stdout_thread = Thread(target=stdout_read)
93 stdout_thread = Thread(target=stdout_read)
94 stderr_thread = Thread(target=stderr_read)
94 stderr_thread = Thread(target=stderr_read)
95
95
96 stdout_thread.start()
96 stdout_thread.start()
97 stderr_thread.start()
97 stderr_thread.start()
98
98
99 # Wait to finish for returncode. Unfortunately, Python has a bug where
99 # Wait to finish for returncode. Unfortunately, Python has a bug where
100 # wait() isn't interruptible (https://bugs.python.org/issue28168) so poll in
100 # wait() isn't interruptible (https://bugs.python.org/issue28168) so poll in
101 # a loop instead of just doing `return p.wait()`
101 # a loop instead of just doing `return p.wait()`
102 while True:
102 while True:
103 result = p.poll()
103 result = p.poll()
104 if result is None:
104 if result is None:
105 time.sleep(0.01)
105 time.sleep(0.01)
106 else:
106 else:
107 break
107 break
108
108
109 # Join the threads to ensure they complete before returning
109 # Join the threads to ensure they complete before returning
110 stdout_thread.join()
110 stdout_thread.join()
111 stderr_thread.join()
111 stderr_thread.join()
112
112
113 return result
113 return result
114
114
115
115
116 def system(cmd: str) -> Optional[int]:
116 def system(cmd: str) -> Optional[int]:
117 """Win32 version of os.system() that works with network shares.
117 """Win32 version of os.system() that works with network shares.
118
118
119 Note that this implementation returns None, as meant for use in IPython.
119 Note that this implementation returns None, as meant for use in IPython.
120
120
121 Parameters
121 Parameters
122 ----------
122 ----------
123 cmd : str or list
123 cmd : str or list
124 A command to be executed in the system shell.
124 A command to be executed in the system shell.
125
125
126 Returns
126 Returns
127 -------
127 -------
128 int : child process' exit code.
128 int : child process' exit code.
129 """
129 """
130 # The controller provides interactivity with both
130 # The controller provides interactivity with both
131 # stdin and stdout
131 # stdin and stdout
132 # import _process_win32_controller
132 # import _process_win32_controller
133 # _process_win32_controller.system(cmd)
133 # _process_win32_controller.system(cmd)
134
134
135 with AvoidUNCPath() as path:
135 with AvoidUNCPath() as path:
136 if path is not None:
136 if path is not None:
137 cmd = '"pushd %s &&"%s' % (path, cmd)
137 cmd = '"pushd %s &&"%s' % (path, cmd)
138 return process_handler(cmd, _system_body)
138 return process_handler(cmd, _system_body)
139
139
140
140
141 def getoutput(cmd: str) -> str:
141 def getoutput(cmd: str) -> str:
142 """Return standard output of executing cmd in a shell.
142 """Return standard output of executing cmd in a shell.
143
143
144 Accepts the same arguments as os.system().
144 Accepts the same arguments as os.system().
145
145
146 Parameters
146 Parameters
147 ----------
147 ----------
148 cmd : str or list
148 cmd : str or list
149 A command to be executed in the system shell.
149 A command to be executed in the system shell.
150
150
151 Returns
151 Returns
152 -------
152 -------
153 stdout : str
153 stdout : str
154 """
154 """
155
155
156 with AvoidUNCPath() as path:
156 with AvoidUNCPath() as path:
157 if path is not None:
157 if path is not None:
158 cmd = '"pushd %s &&"%s' % (path, cmd)
158 cmd = '"pushd %s &&"%s' % (path, cmd)
159 out = process_handler(cmd, lambda p: p.communicate()[0], STDOUT)
159 out = process_handler(cmd, lambda p: p.communicate()[0], STDOUT)
160
160
161 if out is None:
161 if out is None:
162 out = b""
162 out = b""
163 return py3compat.decode(out)
163 return py3compat.decode(out)
164
164
165
165
166 try:
166 try:
167 windll = ctypes.windll # type: ignore [attr-defined]
167 windll = ctypes.windll # type: ignore [attr-defined]
168 CommandLineToArgvW = windll.shell32.CommandLineToArgvW
168 CommandLineToArgvW = windll.shell32.CommandLineToArgvW
169 CommandLineToArgvW.arg_types = [LPCWSTR, POINTER(c_int)]
169 CommandLineToArgvW.arg_types = [LPCWSTR, POINTER(c_int)]
170 CommandLineToArgvW.restype = POINTER(LPCWSTR)
170 CommandLineToArgvW.restype = POINTER(LPCWSTR)
171 LocalFree = windll.kernel32.LocalFree
171 LocalFree = windll.kernel32.LocalFree
172 LocalFree.res_type = HLOCAL
172 LocalFree.res_type = HLOCAL
173 LocalFree.arg_types = [HLOCAL]
173 LocalFree.arg_types = [HLOCAL]
174
174
175 def arg_split(
175 def arg_split(
176 commandline: str, posix: bool = False, strict: bool = True
176 commandline: str, posix: bool = False, strict: bool = True
177 ) -> List[str]:
177 ) -> List[str]:
178 """Split a command line's arguments in a shell-like manner.
178 """Split a command line's arguments in a shell-like manner.
179
179
180 This is a special version for windows that use a ctypes call to CommandLineToArgvW
180 This is a special version for windows that use a ctypes call to CommandLineToArgvW
181 to do the argv splitting. The posix parameter is ignored.
181 to do the argv splitting. The posix parameter is ignored.
182
182
183 If strict=False, process_common.arg_split(...strict=False) is used instead.
183 If strict=False, process_common.arg_split(...strict=False) is used instead.
184 """
184 """
185 # CommandLineToArgvW returns path to executable if called with empty string.
185 # CommandLineToArgvW returns path to executable if called with empty string.
186 if commandline.strip() == "":
186 if commandline.strip() == "":
187 return []
187 return []
188 if not strict:
188 if not strict:
189 # not really a cl-arg, fallback on _process_common
189 # not really a cl-arg, fallback on _process_common
190 return py_arg_split(commandline, posix=posix, strict=strict)
190 return py_arg_split(commandline, posix=posix, strict=strict)
191 argvn = c_int()
191 argvn = c_int()
192 result_pointer = CommandLineToArgvW(commandline.lstrip(), ctypes.byref(argvn))
192 result_pointer = CommandLineToArgvW(commandline.lstrip(), ctypes.byref(argvn))
193 result_array_type = LPCWSTR * argvn.value
193 result_array_type = LPCWSTR * argvn.value
194 result = [
194 result = [
195 arg
195 arg
196 for arg in result_array_type.from_address(
196 for arg in result_array_type.from_address(
197 ctypes.addressof(result_pointer.contents)
197 ctypes.addressof(result_pointer.contents)
198 )
198 )
199 if arg is not None
199 if arg is not None
200 ]
200 ]
201 # for side effects
201 # for side effects
202 _ = LocalFree(result_pointer)
202 _ = LocalFree(result_pointer)
203 return result
203 return result
204 except AttributeError:
204 except AttributeError:
205 arg_split = py_arg_split
205 arg_split = py_arg_split
206
206
207
207
208 def check_pid(pid: int) -> bool:
208 def check_pid(pid: int) -> bool:
209 # OpenProcess returns 0 if no such process (of ours) exists
209 # OpenProcess returns 0 if no such process (of ours) exists
210 # positive int otherwise
210 # positive int otherwise
211 return bool(windll.kernel32.OpenProcess(1, 0, pid))
211 return bool(windll.kernel32.OpenProcess(1, 0, pid))
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