1 files changed, 106 insertions, 0 deletions
diff --git a/Lib/pty.py b/Lib/pty.py
new file mode 100644
index 0000000..53a4b2d
--- /dev/null
+++ b/Lib/pty.py
@@ -0,0 +1,106 @@
+# pty.py -- Pseudo terminal utilities.
+
+# Bugs: No signal handling.  Doesn't set slave termios and window size.
+#	Only tested on Linux.
+# See:  W. Richard Stevens. 1992.  Advanced Programming in the 
+#	UNIX Environment.  Chapter 19.
+# Author: Steen Lumholt -- with additions by Guido.
+
+from select import select
+import os, sys, FCNTL
+import tty
+
+STDIN_FILENO = 0
+STDOUT_FILENO = 1
+STDERR_FILENO = 2
+
+CHILD = 0
+
+# Open pty master.  Returns (master_fd, tty_name).  SGI and Linux/BSD version.
+def master_open():
+	try:
+		import sgi
+	except ImportError:
+		pass
+	else:
+		try:
+		    tty_name, master_fd = sgi._getpty(FCNTL.O_RDWR, 0666, 0)
+		except IOError, msg:
+			raise os.error, msg
+		return master_fd, tty_name
+	for x in 'pqrstuvwxyzPQRST':
+		for y in '0123456789abcdef':
+			pty_name = '/dev/pty' + x + y
+			try:
+				fd = os.open(pty_name, FCNTL.O_RDWR)
+			except os.error:
+				continue
+			return (fd, '/dev/tty' + x + y)
+	raise os.error, 'out of pty devices'
+
+# Open the pty slave.  Acquire the controlling terminal.
+# Returns file descriptor.  Linux version.  (Should be universal? --Guido)
+def slave_open(tty_name):
+	return os.open(tty_name, FCNTL.O_RDWR)
+
+# Fork and make the child a session leader with a controlling terminal.
+# Returns (pid, master_fd)
+def fork():
+	master_fd, tty_name = master_open() 
+	pid = os.fork()
+	if pid == CHILD:
+		# Establish a new session.
+		os.setsid()
+
+		# Acquire controlling terminal.
+		slave_fd = slave_open(tty_name)
+		os.close(master_fd)
+
+		# 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):
+			os.close (slave_fd)
+
+	# Parent and child process.
+	return pid, master_fd
+
+# Write all the data to a descriptor.
+def writen(fd, data):
+	while data != '':
+		n = os.write(fd, data)
+		data = data[n:]
+
+# Default read function.
+def read(fd):
+	return os.read(fd, 1024)
+
+# Parent copy loop.
+# Copies  
+# 	pty master -> standard output	(master_read)
+# 	standard input -> pty master	(stdin_read)
+def copy(master_fd, master_read=read, stdin_read=read):
+	while 1:
+		rfds, wfds, xfds = select(
+			[master_fd, STDIN_FILENO], [], [])
+		if master_fd in rfds:
+			data = master_read(master_fd)
+			os.write(STDOUT_FILENO, data)
+		if STDIN_FILENO in rfds:
+			data = stdin_read(STDIN_FILENO)
+			writen(master_fd, data)
+
+# Create a spawned process.
+def spawn(argv, master_read=read, stdin_read=read):
+	if type(argv) == type(''):
+		argv = (argv,)
+	pid, master_fd = fork()
+	if pid == CHILD:
+		apply(os.execlp, (argv[0],) + argv)
+	mode = tty.tcgetattr(STDIN_FILENO)
+	tty.setraw(STDIN_FILENO)
+	try:
+		copy(master_fd, master_read, stdin_read)
+	except:
+		tty.tcsetattr(STDIN_FILENO, tty.TCSAFLUSH, mode)