如何发送Ctrl-C键控制字符或终端挂断消息，子进程？ [英] How to send Ctrl-C control character or terminal hangup message to child process?

问题描述

我有一个运行在伪终端的一个子进程。父进程不以root身份运行，但孩子的过程呢，通过su或sudo的。因为这个原因，不可能将信号发送到子进程，迫使它退出。我想通过这些手段之一，迫使它退出：

I have a child process which runs in a pseudo terminal. The parent process does not run as root, but the child process does, through su or sudo. Because of this it is not possible to send a signal to the child process to force it to exit. I want to force it to exit by one of these means:

• 模拟一个按Ctrl-C。


• 模拟一个终端挂机。

我该怎么做其中任一？我已经有一个pty主FD，我已经试过这样的事情：

How do I do either of these? I already have a pty master fd, and I've tried something like this:

write(master, &termios.c_cc[VINTR], 1)

但它不会做任何事情。

but it doesn't do anything.

推荐答案

我最终与下述溶液中去：

I eventually went with the following solution:

分叉，而不是立即exec'ing须藤之后，我执行exec（）的辅助子进程来代替，这反过来叉和高管须藤并呼吁waitpid函数就可以了。所以这个过程的层次结构是这样的：

After forking, instead of exec'ing sudo immediately, I exec() a helper child process instead, which in turn forks and execs sudo and calls waitpid on it. So the process hierarchy looks like this:

original process          <---- runs as user
  |
  +-- helper process      <---- runs as user, session leader,
         |                      has own pty, in pty's foreground process group
         |
         +--- sudo        <---- runs as root

通过杀死助手的过程中，PTY没有一个前台进程了。这将导致OS发送SIGHUP到整个前台进程组，无论用户的，所以sudo的是SIGHUP'ed了。

By killing the helper process, the pty does not have a foreground process anymore. This will cause the OS to send SIGHUP to the entire foreground process group, regardless of the user, so sudo is SIGHUP'ed too.

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