"""Pseudo terminal utilities."""
# Bugs: No signal handling. Doesn't set slave termios and window size.
# See: W. Richard Stevens. 1992. Advanced Programming in the
# UNIX Environment. Chapter 19.
# Author: Steen Lumholt -- with additions by Guido.
from select
import select
__all__
= ["openpty","fork","spawn"]
"""openpty() -> (master_fd, slave_fd)
Open a pty master/slave pair, using os.openpty() if possible."""
except (AttributeError, OSError):
master_fd
, slave_name
= _open_terminal()
slave_fd
= slave_open(slave_name
)
return master_fd
, slave_fd
"""master_open() -> (master_fd, slave_name)
Open a pty master and return the fd, and the filename of the slave end.
Deprecated, use openpty() instead."""
master_fd
, slave_fd
= os
.openpty()
except (AttributeError, OSError):
slave_name
= os
.ttyname(slave_fd
)
return master_fd
, slave_name
"""Open pty master and return (master_fd, tty_name).
SGI and generic BSD version, for when openpty() fails."""
tty_name
, master_fd
= sgi
._getpty
(os
.O_RDWR
, 0666, 0)
return master_fd
, tty_name
for x
in 'pqrstuvwxyzPQRST':
for y
in '0123456789abcdef':
pty_name
= '/dev/pty' + x
+ y
fd
= os
.open(pty_name
, os
.O_RDWR
)
return (fd
, '/dev/tty' + x
+ y
)
raise os
.error
, 'out of pty devices'
def slave_open(tty_name
):
"""slave_open(tty_name) -> slave_fd
Open the pty slave and acquire the controlling terminal, returning
Deprecated, use openpty() instead."""
result
= os
.open(tty_name
, os
.O_RDWR
)
from fcntl
import ioctl
, I_PUSH
ioctl(result
, I_PUSH
, "ptem")
ioctl(result
, I_PUSH
, "ldterm")
"""fork() -> (pid, master_fd)
Fork and make the child a session leader with a controlling terminal."""
except (AttributeError, OSError):
# os.forkpty() already set us session leader
master_fd
, slave_fd
= openpty()
# Establish a new session.
# Slave becomes stdin/stdout/stderr of child.
os
.dup2(slave_fd
, STDIN_FILENO
)
os
.dup2(slave_fd
, STDOUT_FILENO
)
os
.dup2(slave_fd
, STDERR_FILENO
)
if (slave_fd
> STDERR_FILENO
):
# Parent and child process.
"""Write all the data to a descriptor."""
"""Default read function."""
def _copy(master_fd
, master_read
=_read
, stdin_read
=_read
):
pty master -> standard output (master_read)
standard input -> pty master (stdin_read)"""
rfds
, wfds
, xfds
= select(
[master_fd
, STDIN_FILENO
], [], [])
data
= master_read(master_fd
)
os
.write(STDOUT_FILENO
, data
)
data
= stdin_read(STDIN_FILENO
)
def spawn(argv
, master_read
=_read
, stdin_read
=_read
):
"""Create a spawned process."""
if type(argv
) == type(''):
os
.execlp(argv
[0], *argv
)
mode
= tty
.tcgetattr(STDIN_FILENO
)
except tty
.error
: # This is the same as termios.error
_copy(master_fd
, master_read
, stdin_read
)
except (IOError, OSError):
tty
.tcsetattr(STDIN_FILENO
, tty
.TCSAFLUSH
, mode
)