Guido van Rossum | 23cb2a8 | 1994-09-12 10:36:35 +0000 | [diff] [blame] | 1 | # pty.py -- Pseudo terminal utilities. |
| 2 | |
| 3 | # Bugs: No signal handling. Doesn't set slave termios and window size. |
| 4 | # Only tested on Linux. |
| 5 | # See: W. Richard Stevens. 1992. Advanced Programming in the |
| 6 | # UNIX Environment. Chapter 19. |
| 7 | # Author: Steen Lumholt -- with additions by Guido. |
| 8 | |
| 9 | from select import select |
| 10 | import os, sys, FCNTL |
| 11 | import tty |
| 12 | |
| 13 | STDIN_FILENO = 0 |
| 14 | STDOUT_FILENO = 1 |
| 15 | STDERR_FILENO = 2 |
| 16 | |
| 17 | CHILD = 0 |
| 18 | |
| 19 | # Open pty master. Returns (master_fd, tty_name). SGI and Linux/BSD version. |
| 20 | def master_open(): |
| 21 | try: |
| 22 | import sgi |
| 23 | except ImportError: |
| 24 | pass |
| 25 | else: |
| 26 | try: |
| 27 | tty_name, master_fd = sgi._getpty(FCNTL.O_RDWR, 0666, 0) |
| 28 | except IOError, msg: |
| 29 | raise os.error, msg |
| 30 | return master_fd, tty_name |
| 31 | for x in 'pqrstuvwxyzPQRST': |
| 32 | for y in '0123456789abcdef': |
| 33 | pty_name = '/dev/pty' + x + y |
| 34 | try: |
| 35 | fd = os.open(pty_name, FCNTL.O_RDWR) |
| 36 | except os.error: |
| 37 | continue |
| 38 | return (fd, '/dev/tty' + x + y) |
| 39 | raise os.error, 'out of pty devices' |
| 40 | |
| 41 | # Open the pty slave. Acquire the controlling terminal. |
| 42 | # Returns file descriptor. Linux version. (Should be universal? --Guido) |
| 43 | def slave_open(tty_name): |
| 44 | return os.open(tty_name, FCNTL.O_RDWR) |
| 45 | |
| 46 | # Fork and make the child a session leader with a controlling terminal. |
| 47 | # Returns (pid, master_fd) |
| 48 | def fork(): |
| 49 | master_fd, tty_name = master_open() |
| 50 | pid = os.fork() |
| 51 | if pid == CHILD: |
| 52 | # Establish a new session. |
| 53 | os.setsid() |
| 54 | |
| 55 | # Acquire controlling terminal. |
| 56 | slave_fd = slave_open(tty_name) |
| 57 | os.close(master_fd) |
| 58 | |
| 59 | # Slave becomes stdin/stdout/stderr of child. |
| 60 | os.dup2(slave_fd, STDIN_FILENO) |
| 61 | os.dup2(slave_fd, STDOUT_FILENO) |
| 62 | os.dup2(slave_fd, STDERR_FILENO) |
| 63 | if (slave_fd > STDERR_FILENO): |
| 64 | os.close (slave_fd) |
| 65 | |
| 66 | # Parent and child process. |
| 67 | return pid, master_fd |
| 68 | |
| 69 | # Write all the data to a descriptor. |
| 70 | def writen(fd, data): |
| 71 | while data != '': |
| 72 | n = os.write(fd, data) |
| 73 | data = data[n:] |
| 74 | |
| 75 | # Default read function. |
| 76 | def read(fd): |
| 77 | return os.read(fd, 1024) |
| 78 | |
| 79 | # Parent copy loop. |
| 80 | # Copies |
| 81 | # pty master -> standard output (master_read) |
| 82 | # standard input -> pty master (stdin_read) |
| 83 | def copy(master_fd, master_read=read, stdin_read=read): |
| 84 | while 1: |
| 85 | rfds, wfds, xfds = select( |
| 86 | [master_fd, STDIN_FILENO], [], []) |
| 87 | if master_fd in rfds: |
| 88 | data = master_read(master_fd) |
| 89 | os.write(STDOUT_FILENO, data) |
| 90 | if STDIN_FILENO in rfds: |
| 91 | data = stdin_read(STDIN_FILENO) |
| 92 | writen(master_fd, data) |
| 93 | |
| 94 | # Create a spawned process. |
| 95 | def spawn(argv, master_read=read, stdin_read=read): |
| 96 | if type(argv) == type(''): |
| 97 | argv = (argv,) |
| 98 | pid, master_fd = fork() |
| 99 | if pid == CHILD: |
| 100 | apply(os.execlp, (argv[0],) + argv) |
| 101 | mode = tty.tcgetattr(STDIN_FILENO) |
| 102 | tty.setraw(STDIN_FILENO) |
| 103 | try: |
| 104 | copy(master_fd, master_read, stdin_read) |
| 105 | except: |
| 106 | tty.tcsetattr(STDIN_FILENO, tty.TCSAFLUSH, mode) |