如何从外部流程将数据写入现有流程的STDIN? [英] How to write data to existing process's STDIN from external process?

问题描述

我正在寻找从外部流程将数据写入现有流程STDIN的方法，并且发现了类似的问题

I'm seeking for ways to write data to the existing process's STDIN from external processes, and found similar question How do you stream data into the STDIN of a program from different local/remote processes in Python? in stackoverlow.

@Michael在该线程中说，我们可以在如下所示的路径中获取现有进程的文件描述符，并允许在Linux上将数据写入它们.

In that thread, @Michael says that we can get file descriptors of existing process in path like below, and permitted to write data into them on Linux.

/proc/$PID/fd/

因此，我创建了一个下面列出的简单脚本，以测试将数据从外部进程写入脚本的STDIN(和TTY).

So, I've created a simple script listed below to test writing data to the script's STDIN (and TTY) from external process.

#!/usr/bin/env python

import os, sys

def get_ttyname():
    for f in sys.stdin, sys.stdout, sys.stderr:
        if f.isatty():
            return os.ttyname(f.fileno())
    return None

if __name__ == "__main__":
    print("Try commands below")

    print("$ echo 'foobar' > {0}".format(get_ttyname()))
    print("$ echo 'foobar' > /proc/{0}/fd/0".format(os.getpid()))

    print("read :: [" + sys.stdin.readline() + "]")

此测试脚本显示STDIN和TTY的路径，然后等待写入STDIN的路径.

This test script shows paths of STDIN and TTY and then, wait for one to write it's STDIN.

我启动了此脚本，并在下面收到了消息.

I launched this script and got messages below.

Try commands below
$ echo 'foobar' > /dev/pts/6
$ echo 'foobar' > /proc/3308/fd/0

因此，我从其他终端执行了命令echo 'foobar' > /dev/pts/6和echo 'foobar' > /proc/3308/fd/0.执行完这两个命令后，在正在运行测试脚本的终端上两次显示消息foobar，仅此而已. print("read :: [" + sys.stdin.readline() + "]")行未执行.

So, I executed the command echo 'foobar' > /dev/pts/6 and echo 'foobar' > /proc/3308/fd/0 from other terminal. After execution of both commands, message foobar is displayed twice on the terminal the test script is running on, but that's all. The line print("read :: [" + sys.stdin.readline() + "]") was not executed.

是否有任何方法可以将来自外部进程的数据写入现有进程的STDIN(或其他文件描述符)，即从其他进程中调用line print("read :: [" + sys.stdin.readline() + "]")的执行?

Are there any ways to write data from external processes to the existing process's STDIN (or other file descriptors), i.e. invoke execution of the lineprint("read :: [" + sys.stdin.readline() + "]") from other processes?

推荐答案

您的代码将不起作用.
/proc/pid/fd/0是/dev/pts/6文件的链接.

Your code will not work.
/proc/pid/fd/0 is a link to the /dev/pts/6 file.

$ echo'foobar'>/dev/pts/6
$ echo'foobar'>/proc/pid/fd/0

$ echo 'foobar' > /dev/pts/6
$ echo 'foobar' > /proc/pid/fd/0

由于两个命令均写入终端.此输入将转到终端，而不是进程.

Since both the commands write to the terminal. This input goes to terminal and not to the process.

如果stdin最初是管道，它将起作用.
例如，test.py是:

It will work if stdin intially is a pipe.
For example, test.py is :

#!/usr/bin/python

import os, sys
if __name__ == "__main__":
    print("Try commands below")
    print("$ echo 'foobar' > /proc/{0}/fd/0".format(os.getpid()))
    while True:
        print("read :: [" + sys.stdin.readline() + "]")
        pass

运行方式为:

$ (while [ 1 ]; do sleep 1; done) | python test.py

现在从另一个终端将内容写入/proc/pid/fd/0，它将到达test.py

Now from another terminal write something to /proc/pid/fd/0 and it will come to test.py

这篇关于如何从外部流程将数据写入现有流程的STDIN?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！