将 ^C 发送到 Windows 上的 Python 子进程对象

I have a test harness (written in Python) that needs to shut down the program under test (written in C) by sending it ^C. On Unix,

proc.send_signal(signal.SIGINT)

工作完美。在 Windows 上，这会引发错误（“不支持信号 2”或类似的错误）。我在 Windows 上使用 Python 2.7，所以我觉得我应该可以这样做

proc.send_signal(signal.CTRL_C_EVENT)

但这根本没有任何作用。我需要做什么？这是创建子流程的代码：

# Windows needs an extra argument passed to subprocess.Popen,
# but the constant isn't defined on Unix.
try: kwargs['creationflags'] = subprocess.CREATE_NEW_PROCESS_GROUP
except AttributeError: pass
proc = subprocess.Popen(argv,
                        stdin=open(os.path.devnull, "r"),
                        stdout=subprocess.PIPE,
                        stderr=subprocess.PIPE,
                        **kwargs)

有一个解决方案是使用包装器（如 Vinay 提供的链接中所述），该包装器在 Windows 的新控制台窗口中启动start命令。

包装器的代码：

#wrapper.py
import subprocess, time, signal, sys, os

def signal_handler(signal, frame):
  time.sleep(1)
  print 'Ctrl+C received in wrapper.py'

signal.signal(signal.SIGINT, signal_handler)
print "wrapper.py started"
subprocess.Popen("python demo.py")
time.sleep(3) #Replace with your IPC code here, which waits on a fire CTRL-C request
os.kill(signal.CTRL_C_EVENT, 0)

捕获 CTRL-C 的程序代码：

#demo.py

import signal, sys, time

def signal_handler(signal, frame):
  print 'Ctrl+C received in demo.py'
  time.sleep(1)
  sys.exit(0)

signal.signal(signal.SIGINT, signal_handler)
print 'demo.py started'
#signal.pause() # does not work under Windows
while(True):
  time.sleep(1)

启动包装器，例如：

PythonPrompt> import subprocess
PythonPrompt> subprocess.Popen("start python wrapper.py", shell=True)

您需要添加一些 IPC 代码，以允许您控制包装器触发 os.kill(signal.CTRL_C_EVENT, 0) 命令。我在我的应用程序中使用了套接字来实现此目的。

解释：

预先信息

• send_signal(CTRL_C_EVENT)不起作用，因为CTRL_C_EVENT只为os.kill. [REF1] http://docs.python.org/library/signal.html#signal.CTRL_C_EVENT
• os.kill(CTRL_C_EVENT)向当前cmd窗口中运行的所有进程发送信号[REF2] http://msdn.microsoft.com/en-us/library/windows/desktop/ms683155%28v=vs.85%29.aspx
• Popen(..., creationflags=CREATE_NEW_PROCESS_GROUP)不起作用，因为CTRL_C_EVENT对于进程组将被忽略。[REF2] http://msdn.microsoft.com/en-us/library/windows/desktop/ms683155%28v=vs.85%29.aspx这是Python文档中的一个错误[REF3] http://docs.python.org/library/subprocess.html#subprocess.Popen.send_signal

实施的解决方案

1. 让你的程序使用 Windows shell 命令在不同的 cmd 窗口中运行start.
2. 在控制应用程序和应获取 CTRL-C 信号的应用程序之间添加 CTRL-C 请求包装器。包装器将在与应获取 CTRL-C 信号的应用程序相同的 cmd 窗口中运行。
3. 包装器将自行关闭，并且程序将通过向 cmd 窗口中的所有进程发送 CTRL_C_EVENT 来获取 CTRL-C 信号。
4. 控制程序应该能够请求包装器发送 CTRL-C 信号。这可以通过 IPC 方式实现，例如插座。

有用的帖子是：

我必须删除链接前面的 http，因为我是新用户，不允许发布两个以上的链接。

• http://social.msdn.microsoft.com/Forums/en-US/windowsgeneraldevelopmentissues/thread/dc9586ab-1ee8-41aa-a775-cf4828ac1239/#6589714f-12a7-447e-b214-27372f31ca11 http://social.msdn.microsoft.com/Forums/en-US/windowsgeneraldevelopmentissues/thread/dc9586ab-1ee8-41aa-a775-cf4828ac1239/#6589714f-12a7-447e-b214-27372f31ca11
• 我可以向 Windows 上的应用程序发送 ctrl-C (SIGINT) 吗？ https://stackoverflow.com/questions/813086/can-i-send-a-ctrl-c-sigint-to-an-application-on-windows/2445728#2445728
• 向python的子进程发送SIGINT https://stackoverflow.com/questions/1095549/sending-sigint-to-a-subprocess-of-python
• http://bugs.python.org/issue9524 http://bugs.python.org/issue9524
• http://ss64.com/nt/start.html http://ss64.com/nt/start.html
• http://objectmix.com/python/387639-sending-cntrl-c.html#post1443948 http://objectmix.com/python/387639-sending-cntrl-c.html#post1443948

更新：基于 IPC 的 CTRL-C 包装器

在这里你可以找到一个自写的 python 模块，提供 CTRL-C 包装，包括基于套接字的 IPC。 语法与 subprocess 模块非常相似。

Usage:

>>> import winctrlc
>>> p1 = winctrlc.Popen("python demo.py")
>>> p2 = winctrlc.Popen("python demo.py")
>>> p3 = winctrlc.Popen("python demo.py")
>>> p2.send_ctrl_c()
>>> p1.send_ctrl_c()
>>> p3.send_ctrl_c()

Code

import socket
import subprocess
import time
import random
import signal, os, sys


class Popen:
  _port = random.randint(10000, 50000)
  _connection = ''

  def _start_ctrl_c_wrapper(self, cmd):
    cmd_str = "start \"\" python winctrlc.py "+"\""+cmd+"\""+" "+str(self._port)
    subprocess.Popen(cmd_str, shell=True)

  def _create_connection(self):
    self._connection = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    self._connection.connect(('localhost', self._port))

  def send_ctrl_c(self):
    self._connection.send(Wrapper.TERMINATION_REQ)
    self._connection.close()

  def __init__(self, cmd):
    self._start_ctrl_c_wrapper(cmd)
    self._create_connection()


class Wrapper:
  TERMINATION_REQ = "Terminate with CTRL-C"

  def _create_connection(self, port):
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.bind(('localhost', port))
    s.listen(1)
    conn, addr = s.accept()
    return conn

  def _wait_on_ctrl_c_request(self, conn):
    while True:
      data = conn.recv(1024)
      if data == self.TERMINATION_REQ:
        ctrl_c_received = True
        break
      else:
        ctrl_c_received = False
    return ctrl_c_received

  def _cleanup_and_fire_ctrl_c(self, conn):
    conn.close()
    os.kill(signal.CTRL_C_EVENT, 0)

  def _signal_handler(self, signal, frame):
    time.sleep(1)
    sys.exit(0)

  def __init__(self, cmd, port):
    signal.signal(signal.SIGINT, self._signal_handler)
    subprocess.Popen(cmd)
    conn = self._create_connection(port)
    ctrl_c_req_received = self._wait_on_ctrl_c_request(conn)
    if ctrl_c_req_received:
      self._cleanup_and_fire_ctrl_c(conn)
    else:
      sys.exit(0)


if __name__ == "__main__":
  command_string = sys.argv[1]
  port_no = int(sys.argv[2])
  Wrapper(command_string, port_no)