Python code coverage for Lib/pty.py

#	count	content
1	n/a	"""Pseudo terminal utilities."""
2	n/a
3	n/a	# Bugs: No signal handling. Doesn't set slave termios and window size.
4	n/a	# Only tested on Linux.
5	n/a	# See: W. Richard Stevens. 1992. Advanced Programming in the
6	n/a	# UNIX Environment. Chapter 19.
7	n/a	# Author: Steen Lumholt -- with additions by Guido.
8	n/a
9	n/a	from select import select
10	n/a	import os
11	n/a	import tty
12	n/a
13	n/a	__all__ = ["openpty","fork","spawn"]
14	n/a
15	n/a	STDIN_FILENO = 0
16	n/a	STDOUT_FILENO = 1
17	n/a	STDERR_FILENO = 2
18	n/a
19	n/a	CHILD = 0
20	n/a
21	n/a	def openpty():
22	n/a	"""openpty() -> (master_fd, slave_fd)
23	n/a	Open a pty master/slave pair, using os.openpty() if possible."""
24	n/a
25	n/a	try:
26	n/a	return os.openpty()
27	n/a	except (AttributeError, OSError):
28	n/a	pass
29	n/a	master_fd, slave_name = _open_terminal()
30	n/a	slave_fd = slave_open(slave_name)
31	n/a	return master_fd, slave_fd
32	n/a
33	n/a	def master_open():
34	n/a	"""master_open() -> (master_fd, slave_name)
35	n/a	Open a pty master and return the fd, and the filename of the slave end.
36	n/a	Deprecated, use openpty() instead."""
37	n/a
38	n/a	try:
39	n/a	master_fd, slave_fd = os.openpty()
40	n/a	except (AttributeError, OSError):
41	n/a	pass
42	n/a	else:
43	n/a	slave_name = os.ttyname(slave_fd)
44	n/a	os.close(slave_fd)
45	n/a	return master_fd, slave_name
46	n/a
47	n/a	return _open_terminal()
48	n/a
49	n/a	def _open_terminal():
50	n/a	"""Open pty master and return (master_fd, tty_name)."""
51	n/a	for x in 'pqrstuvwxyzPQRST':
52	n/a	for y in '0123456789abcdef':
53	n/a	pty_name = '/dev/pty' + x + y
54	n/a	try:
55	n/a	fd = os.open(pty_name, os.O_RDWR)
56	n/a	except OSError:
57	n/a	continue
58	n/a	return (fd, '/dev/tty' + x + y)
59	n/a	raise OSError('out of pty devices')
60	n/a
61	n/a	def slave_open(tty_name):
62	n/a	"""slave_open(tty_name) -> slave_fd
63	n/a	Open the pty slave and acquire the controlling terminal, returning
64	n/a	opened filedescriptor.
65	n/a	Deprecated, use openpty() instead."""
66	n/a
67	n/a	result = os.open(tty_name, os.O_RDWR)
68	n/a	try:
69	n/a	from fcntl import ioctl, I_PUSH
70	n/a	except ImportError:
71	n/a	return result
72	n/a	try:
73	n/a	ioctl(result, I_PUSH, "ptem")
74	n/a	ioctl(result, I_PUSH, "ldterm")
75	n/a	except OSError:
76	n/a	pass
77	n/a	return result
78	n/a
79	n/a	def fork():
80	n/a	"""fork() -> (pid, master_fd)
81	n/a	Fork and make the child a session leader with a controlling terminal."""
82	n/a
83	n/a	try:
84	n/a	pid, fd = os.forkpty()
85	n/a	except (AttributeError, OSError):
86	n/a	pass
87	n/a	else:
88	n/a	if pid == CHILD:
89	n/a	try:
90	n/a	os.setsid()
91	n/a	except OSError:
92	n/a	# os.forkpty() already set us session leader
93	n/a	pass
94	n/a	return pid, fd
95	n/a
96	n/a	master_fd, slave_fd = openpty()
97	n/a	pid = os.fork()
98	n/a	if pid == CHILD:
99	n/a	# Establish a new session.
100	n/a	os.setsid()
101	n/a	os.close(master_fd)
102	n/a
103	n/a	# Slave becomes stdin/stdout/stderr of child.
104	n/a	os.dup2(slave_fd, STDIN_FILENO)
105	n/a	os.dup2(slave_fd, STDOUT_FILENO)
106	n/a	os.dup2(slave_fd, STDERR_FILENO)
107	n/a	if (slave_fd > STDERR_FILENO):
108	n/a	os.close (slave_fd)
109	n/a
110	n/a	# Explicitly open the tty to make it become a controlling tty.
111	n/a	tmp_fd = os.open(os.ttyname(STDOUT_FILENO), os.O_RDWR)
112	n/a	os.close(tmp_fd)
113	n/a	else:
114	n/a	os.close(slave_fd)
115	n/a
116	n/a	# Parent and child process.
117	n/a	return pid, master_fd
118	n/a
119	n/a	def _writen(fd, data):
120	n/a	"""Write all the data to a descriptor."""
121	n/a	while data:
122	n/a	n = os.write(fd, data)
123	n/a	data = data[n:]
124	n/a
125	n/a	def _read(fd):
126	n/a	"""Default read function."""
127	n/a	return os.read(fd, 1024)
128	n/a
129	n/a	def _copy(master_fd, master_read=_read, stdin_read=_read):
130	n/a	"""Parent copy loop.
131	n/a	Copies
132	n/a	pty master -> standard output (master_read)
133	n/a	standard input -> pty master (stdin_read)"""
134	n/a	fds = [master_fd, STDIN_FILENO]
135	n/a	while True:
136	n/a	rfds, wfds, xfds = select(fds, [], [])
137	n/a	if master_fd in rfds:
138	n/a	data = master_read(master_fd)
139	n/a	if not data: # Reached EOF.
140	n/a	fds.remove(master_fd)
141	n/a	else:
142	n/a	os.write(STDOUT_FILENO, data)
143	n/a	if STDIN_FILENO in rfds:
144	n/a	data = stdin_read(STDIN_FILENO)
145	n/a	if not data:
146	n/a	fds.remove(STDIN_FILENO)
147	n/a	else:
148	n/a	_writen(master_fd, data)
149	n/a
150	n/a	def spawn(argv, master_read=_read, stdin_read=_read):
151	n/a	"""Create a spawned process."""
152	n/a	if type(argv) == type(''):
153	n/a	argv = (argv,)
154	n/a	pid, master_fd = fork()
155	n/a	if pid == CHILD:
156	n/a	os.execlp(argv[0], *argv)
157	n/a	try:
158	n/a	mode = tty.tcgetattr(STDIN_FILENO)
159	n/a	tty.setraw(STDIN_FILENO)
160	n/a	restore = 1
161	n/a	except tty.error: # This is the same as termios.error
162	n/a	restore = 0
163	n/a	try:
164	n/a	_copy(master_fd, master_read, stdin_read)
165	n/a	except OSError:
166	n/a	if restore:
167	n/a	tty.tcsetattr(STDIN_FILENO, tty.TCSAFLUSH, mode)
168	n/a
169	n/a	os.close(master_fd)
170	n/a	return os.waitpid(pid, 0)[1]