home *** CD-ROM | disk | FTP | other *** search
- # 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)
-