无法使用 termios.TIOCSTI 伪造终端输入

Question

大部分code samples I've seen are trying to read from stdin without local echo. To do this they modify the "local modes" flag to remove the setting to "Echo input characters". I thought I could just modify the "input modes" flag to TIOCSTI which is for "Insert the given byte in the input queue.". However, even though I run the script as root, it has no effect. anything I write to the fd seems to go to the terminal output, rather than the terminal input. Basically what I want to do is this exact thing，但纯python。

"""
termfake.py

Usage: sudo python termfake.py /dev/ttys002

Get the tty device path of a different local termimal by running `tty`
in that terminal.
"""

import sys
import termios

fd = open(sys.argv[1], 'w')
fdno = fd.fileno()

# Returns [iflag, oflag, cflag, lflag, ispeed, ospeed, cc]
tatters = termios.tcgetattr(fdno)
print('original', tatters)
tatters[0] = termios.TIOCSTI
print('TIOCSTI', termios.TIOCSTI)

# Set iflag
termios.tcsetattr(fdno, termios.TCSANOW, tatters)

# Verify setting change
with open('/dev/ttys002', 'w') as fd2:
    print('modified', termios.tcgetattr(fd2.fileno()))

fd.write('This is test\n')
fd.close()

Answer 1

TIOCSTI 是一个 ioctl（记录在 tty_ioctl(4) 中），不是终端设置，所以你不能使用 tcsetattr() -- 你需要输入假的每个字符输入 ioctl() 代替。以前从来不需要从 Python 执行 ioctl，但以下似乎适用于不同终端中的运行和 ls（指定为参数，例如 /dev/pts/13) 那是运行 Bash:

import fcntl
import sys
import termios

with open(sys.argv[1], 'w') as fd:
    for c in "ls\n":
        fcntl.ioctl(fd, termios.TIOCSTI, c)

顺便说一下，

TIOCSTI 需要 root 权限（或 CAP_SYS_ADMIN 更具体，但实际上通常是相同的）——参见 capabilities(7).

Answer 2

我从@Ulfalizer 那里得到了答案并将其扩展为一个完整且可用的应用程序。

import sys
import fcntl
import termios
import argparse

parser = argparse.ArgumentParser()
parser.add_argument('tty', type=argparse.FileType('w'),
                    help='full tty path as given by the tty command')
group = parser.add_mutually_exclusive_group()
group.add_argument('-n', action='store_true',
                   help='prevent sending a trailing newline character')
group.add_argument('--stdin', action='store_true',
                   help='read input from stdin')
group = parser.add_argument_group()
group.add_argument('cmd', nargs='?',
                    help='command to run (required if not using --stdin)')
group.add_argument('args', nargs='*',
                    help='arguments to command')
args = parser.parse_known_args()

if args.stdin:
    data = sys.stdin.read()
else:
    data = ' '.join([args.cmd] + args.args)

for c in data:
    fcntl.ioctl(args.tty, termios.TIOCSTI, c)
if not args.n and data[-1][-1] != '\n':
    fcntl.ioctl(args.tty, termios.TIOCSTI, '\n')

以下是您的使用方法：

1 号航站楼： 做...

$ tty > /tmp/t1

2 号航站楼： 做...

$ sudo python termfake.py $(cat /tmp/t1) date +%s

1 号航站楼： 观察...

$ tty > /tmp/t1
$ date +%s
1487276400

无法使用 termios.TIOCSTI 伪造终端输入

Unable to fake terminal input with termios.TIOCSTI

python

linux

terminal