"""Pseudo terminal utilities."""

[0] Fix | Delete

[1] Fix | Delete

# Bugs: No signal handling. Doesn't set slave termios and window size.

[2] Fix | Delete

# Only tested on Linux.

[3] Fix | Delete

# See: W. Richard Stevens. 1992. Advanced Programming in the

[4] Fix | Delete

# UNIX Environment. Chapter 19.

[5] Fix | Delete

# Author: Steen Lumholt -- with additions by Guido.

[6] Fix | Delete

[7] Fix | Delete

from select import select

[8] Fix | Delete

import os

[9] Fix | Delete

import tty

[10] Fix | Delete

[11] Fix | Delete

__all__ = ["openpty","fork","spawn"]

[12] Fix | Delete

[13] Fix | Delete

STDIN_FILENO = 0

[14] Fix | Delete

STDOUT_FILENO = 1

[15] Fix | Delete

STDERR_FILENO = 2

[16] Fix | Delete

[17] Fix | Delete

CHILD = 0

[18] Fix | Delete

[19] Fix | Delete

def openpty():

[20] Fix | Delete

"""openpty() -> (master_fd, slave_fd)

[21] Fix | Delete

Open a pty master/slave pair, using os.openpty() if possible."""

[22] Fix | Delete

[23] Fix | Delete

try:

[24] Fix | Delete

return os.openpty()

[25] Fix | Delete

except (AttributeError, OSError):

[26] Fix | Delete

pass

[27] Fix | Delete

master_fd, slave_name = _open_terminal()

[28] Fix | Delete

slave_fd = slave_open(slave_name)

[29] Fix | Delete

return master_fd, slave_fd

[30] Fix | Delete

[31] Fix | Delete

def master_open():

[32] Fix | Delete

"""master_open() -> (master_fd, slave_name)

[33] Fix | Delete

Open a pty master and return the fd, and the filename of the slave end.

[34] Fix | Delete

Deprecated, use openpty() instead."""

[35] Fix | Delete

[36] Fix | Delete

try:

[37] Fix | Delete

master_fd, slave_fd = os.openpty()

[38] Fix | Delete

except (AttributeError, OSError):

[39] Fix | Delete

pass

[40] Fix | Delete

else:

[41] Fix | Delete

slave_name = os.ttyname(slave_fd)

[42] Fix | Delete

os.close(slave_fd)

[43] Fix | Delete

return master_fd, slave_name

[44] Fix | Delete

[45] Fix | Delete

return _open_terminal()

[46] Fix | Delete

[47] Fix | Delete

def _open_terminal():

[48] Fix | Delete

"""Open pty master and return (master_fd, tty_name)."""

[49] Fix | Delete

for x in 'pqrstuvwxyzPQRST':

[50] Fix | Delete

for y in '0123456789abcdef':

[51] Fix | Delete

pty_name = '/dev/pty' + x + y

[52] Fix | Delete

try:

[53] Fix | Delete

fd = os.open(pty_name, os.O_RDWR)

[54] Fix | Delete

except OSError:

[55] Fix | Delete

continue

[56] Fix | Delete

return (fd, '/dev/tty' + x + y)

[57] Fix | Delete

raise OSError('out of pty devices')

[58] Fix | Delete

[59] Fix | Delete

def slave_open(tty_name):

[60] Fix | Delete

"""slave_open(tty_name) -> slave_fd

[61] Fix | Delete

Open the pty slave and acquire the controlling terminal, returning

[62] Fix | Delete

opened filedescriptor.

[63] Fix | Delete

Deprecated, use openpty() instead."""

[64] Fix | Delete

[65] Fix | Delete

result = os.open(tty_name, os.O_RDWR)

[66] Fix | Delete

try:

[67] Fix | Delete

from fcntl import ioctl, I_PUSH

[68] Fix | Delete

except ImportError:

[69] Fix | Delete

return result

[70] Fix | Delete

try:

[71] Fix | Delete

ioctl(result, I_PUSH, "ptem")

[72] Fix | Delete

ioctl(result, I_PUSH, "ldterm")

[73] Fix | Delete

except OSError:

[74] Fix | Delete

pass

[75] Fix | Delete

return result

[76] Fix | Delete

[77] Fix | Delete

def fork():

[78] Fix | Delete

"""fork() -> (pid, master_fd)

[79] Fix | Delete

Fork and make the child a session leader with a controlling terminal."""

[80] Fix | Delete

[81] Fix | Delete

try:

[82] Fix | Delete

pid, fd = os.forkpty()

[83] Fix | Delete

except (AttributeError, OSError):

[84] Fix | Delete

pass

[85] Fix | Delete

else:

[86] Fix | Delete

if pid == CHILD:

[87] Fix | Delete

try:

[88] Fix | Delete

os.setsid()

[89] Fix | Delete

except OSError:

[90] Fix | Delete

# os.forkpty() already set us session leader

[91] Fix | Delete

pass

[92] Fix | Delete

return pid, fd

[93] Fix | Delete

[94] Fix | Delete

master_fd, slave_fd = openpty()

[95] Fix | Delete

pid = os.fork()

[96] Fix | Delete

if pid == CHILD:

[97] Fix | Delete

# Establish a new session.

[98] Fix | Delete

os.setsid()

[99] Fix | Delete

os.close(master_fd)

[100] Fix | Delete

[101] Fix | Delete

# Slave becomes stdin/stdout/stderr of child.

[102] Fix | Delete

os.dup2(slave_fd, STDIN_FILENO)

[103] Fix | Delete

os.dup2(slave_fd, STDOUT_FILENO)

[104] Fix | Delete

os.dup2(slave_fd, STDERR_FILENO)

[105] Fix | Delete

if (slave_fd > STDERR_FILENO):

[106] Fix | Delete

os.close (slave_fd)

[107] Fix | Delete

[108] Fix | Delete

# Explicitly open the tty to make it become a controlling tty.

[109] Fix | Delete

tmp_fd = os.open(os.ttyname(STDOUT_FILENO), os.O_RDWR)

[110] Fix | Delete

os.close(tmp_fd)

[111] Fix | Delete

else:

[112] Fix | Delete

os.close(slave_fd)

[113] Fix | Delete

[114] Fix | Delete

# Parent and child process.

[115] Fix | Delete

return pid, master_fd

[116] Fix | Delete

[117] Fix | Delete

def _writen(fd, data):

[118] Fix | Delete

"""Write all the data to a descriptor."""

[119] Fix | Delete

while data:

[120] Fix | Delete

n = os.write(fd, data)

[121] Fix | Delete

data = data[n:]

[122] Fix | Delete

[123] Fix | Delete

def _read(fd):

[124] Fix | Delete

"""Default read function."""

[125] Fix | Delete

return os.read(fd, 1024)

[126] Fix | Delete

[127] Fix | Delete

def _copy(master_fd, master_read=_read, stdin_read=_read):

[128] Fix | Delete

"""Parent copy loop.

[129] Fix | Delete

Copies

[130] Fix | Delete

pty master -> standard output (master_read)

[131] Fix | Delete

standard input -> pty master (stdin_read)"""

[132] Fix | Delete

fds = [master_fd, STDIN_FILENO]

[133] Fix | Delete

while True:

[134] Fix | Delete

rfds, wfds, xfds = select(fds, [], [])

[135] Fix | Delete

if master_fd in rfds:

[136] Fix | Delete

data = master_read(master_fd)

[137] Fix | Delete

if not data: # Reached EOF.

[138] Fix | Delete

fds.remove(master_fd)

[139] Fix | Delete

else:

[140] Fix | Delete

os.write(STDOUT_FILENO, data)

[141] Fix | Delete

if STDIN_FILENO in rfds:

[142] Fix | Delete

data = stdin_read(STDIN_FILENO)

[143] Fix | Delete

if not data:

[144] Fix | Delete

fds.remove(STDIN_FILENO)

[145] Fix | Delete

else:

[146] Fix | Delete

_writen(master_fd, data)

[147] Fix | Delete

[148] Fix | Delete

def spawn(argv, master_read=_read, stdin_read=_read):

[149] Fix | Delete

"""Create a spawned process."""

[150] Fix | Delete

if type(argv) == type(''):

[151] Fix | Delete

argv = (argv,)

[152] Fix | Delete

pid, master_fd = fork()

[153] Fix | Delete

if pid == CHILD:

[154] Fix | Delete

os.execlp(argv[0], *argv)

[155] Fix | Delete

try:

[156] Fix | Delete

mode = tty.tcgetattr(STDIN_FILENO)

[157] Fix | Delete

tty.setraw(STDIN_FILENO)

[158] Fix | Delete

restore = 1

[159] Fix | Delete

except tty.error: # This is the same as termios.error

[160] Fix | Delete

restore = 0

[161] Fix | Delete

try:

[162] Fix | Delete

_copy(master_fd, master_read, stdin_read)

[163] Fix | Delete

except OSError:

[164] Fix | Delete

if restore:

[165] Fix | Delete

tty.tcsetattr(STDIN_FILENO, tty.TCSAFLUSH, mode)

[166] Fix | Delete

[167] Fix | Delete

os.close(master_fd)

[168] Fix | Delete

return os.waitpid(pid, 0)[1]

[169] Fix | Delete

[170] Fix | Delete