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Sep 12, 1994
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Sep 12, 1994
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100644
187 lines (157 sloc)
5.09 KB
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# Bugs: No signal handling. Doesn't set slave termios and window size.
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# See: W. Richard Stevens. 1992. Advanced Programming in the
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# UNIX Environment. Chapter 19.
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# Author: Steen Lumholt -- with additions by Guido.
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from select import select
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import tty
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# names imported directly for test mocking purposes
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from os import close, waitpid
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from tty import setraw, tcgetattr, tcsetattr
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__all__ = ["openpty", "fork", "spawn"]
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STDIN_FILENO = 0
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STDOUT_FILENO = 1
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STDERR_FILENO = 2
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CHILD = 0
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"""openpty() -> (master_fd, slave_fd)
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Open a pty master/slave pair, using os.openpty() if possible."""
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try:
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return os.openpty()
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except (AttributeError, OSError):
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pass
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master_fd, slave_name = _open_terminal()
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slave_fd = slave_open(slave_name)
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return master_fd, slave_fd
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def master_open():
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"""master_open() -> (master_fd, slave_name)
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Open a pty master and return the fd, and the filename of the slave end.
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Deprecated, use openpty() instead."""
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try:
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master_fd, slave_fd = os.openpty()
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except (AttributeError, OSError):
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pass
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else:
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slave_name = os.ttyname(slave_fd)
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os.close(slave_fd)
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return master_fd, slave_name
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for x in 'pqrstuvwxyzPQRST':
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for y in '0123456789abcdef':
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pty_name = '/dev/pty' + x + y
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try:
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def slave_open(tty_name):
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"""slave_open(tty_name) -> slave_fd
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Open the pty slave and acquire the controlling terminal, returning
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opened filedescriptor.
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Deprecated, use openpty() instead."""
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def fork():
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"""fork() -> (pid, master_fd)
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Fork and make the child a session leader with a controlling terminal."""
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try:
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pid, fd = os.forkpty()
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except (AttributeError, OSError):
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pass
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else:
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if pid == CHILD:
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try:
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os.setsid()
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except OSError:
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# os.forkpty() already set us session leader
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pass
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return pid, fd
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master_fd, slave_fd = openpty()
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pid = os.fork()
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if pid == CHILD:
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# Establish a new session.
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os.setsid()
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os.close(master_fd)
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# Slave becomes stdin/stdout/stderr of child.
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os.dup2(slave_fd, STDIN_FILENO)
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os.dup2(slave_fd, STDOUT_FILENO)
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os.dup2(slave_fd, STDERR_FILENO)
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# Explicitly open the tty to make it become a controlling tty.
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tmp_fd = os.open(os.ttyname(STDOUT_FILENO), os.O_RDWR)
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os.close(tmp_fd)
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"""Parent copy loop.
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Copies
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pty master -> standard output (master_read)
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standard input -> pty master (stdin_read)"""
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# Some OSes signal EOF by returning an empty byte string,
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# some throw OSErrors.
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try:
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data = master_read(master_fd)
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except OSError:
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data = b""
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return # Assume the child process has exited and is
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# unreachable, so we clean up.
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