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author | nkozlovskiy <nmk@ydb.tech> | 2023-09-29 12:24:06 +0300 |
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committer | nkozlovskiy <nmk@ydb.tech> | 2023-09-29 12:41:34 +0300 |
commit | e0e3e1717e3d33762ce61950504f9637a6e669ed (patch) | |
tree | bca3ff6939b10ed60c3d5c12439963a1146b9711 /contrib/tools/python3/src/Lib/pty.py | |
parent | 38f2c5852db84c7b4d83adfcb009eb61541d1ccd (diff) | |
download | ydb-e0e3e1717e3d33762ce61950504f9637a6e669ed.tar.gz |
add ydb deps
Diffstat (limited to 'contrib/tools/python3/src/Lib/pty.py')
-rw-r--r-- | contrib/tools/python3/src/Lib/pty.py | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/contrib/tools/python3/src/Lib/pty.py b/contrib/tools/python3/src/Lib/pty.py new file mode 100644 index 0000000000..fefb63abfb --- /dev/null +++ b/contrib/tools/python3/src/Lib/pty.py @@ -0,0 +1,217 @@ +"""Pseudo terminal utilities.""" + +# Bugs: No signal handling. Doesn't set slave termios and window size. +# Only tested on Linux, FreeBSD, and macOS. +# 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 +import sys +import tty + +# names imported directly for test mocking purposes +from os import close, waitpid +from tty import setraw, tcgetattr, tcsetattr + +__all__ = ["openpty", "fork", "spawn"] + +STDIN_FILENO = 0 +STDOUT_FILENO = 1 +STDERR_FILENO = 2 + +CHILD = 0 + +def openpty(): + """openpty() -> (master_fd, slave_fd) + Open a pty master/slave pair, using os.openpty() if possible.""" + + try: + return os.openpty() + except (AttributeError, OSError): + pass + master_fd, slave_name = _open_terminal() + slave_fd = slave_open(slave_name) + return master_fd, slave_fd + +def master_open(): + """master_open() -> (master_fd, slave_name) + Open a pty master and return the fd, and the filename of the slave end. + Deprecated, use openpty() instead.""" + + try: + master_fd, slave_fd = os.openpty() + except (AttributeError, OSError): + pass + else: + slave_name = os.ttyname(slave_fd) + os.close(slave_fd) + return master_fd, slave_name + + return _open_terminal() + +def _open_terminal(): + """Open pty master and 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, os.O_RDWR) + except OSError: + continue + return (fd, '/dev/tty' + x + y) + raise OSError('out of pty devices') + +def slave_open(tty_name): + """slave_open(tty_name) -> slave_fd + Open the pty slave and acquire the controlling terminal, returning + opened filedescriptor. + Deprecated, use openpty() instead.""" + + result = os.open(tty_name, os.O_RDWR) + try: + from fcntl import ioctl, I_PUSH + except ImportError: + return result + try: + ioctl(result, I_PUSH, "ptem") + ioctl(result, I_PUSH, "ldterm") + except OSError: + pass + return result + +def fork(): + """fork() -> (pid, master_fd) + Fork and make the child a session leader with a controlling terminal.""" + + try: + pid, fd = os.forkpty() + except (AttributeError, OSError): + pass + else: + if pid == CHILD: + try: + os.setsid() + except OSError: + # os.forkpty() already set us session leader + pass + return pid, fd + + master_fd, slave_fd = openpty() + pid = os.fork() + if pid == CHILD: + # Establish a new session. + os.setsid() + 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) + + # Explicitly open the tty to make it become a controlling tty. + tmp_fd = os.open(os.ttyname(STDOUT_FILENO), os.O_RDWR) + os.close(tmp_fd) + else: + os.close(slave_fd) + + # Parent and child process. + return pid, master_fd + +def _read(fd): + """Default read function.""" + return os.read(fd, 1024) + +def _copy(master_fd, master_read=_read, stdin_read=_read): + """Parent copy loop. + Copies + pty master -> standard output (master_read) + standard input -> pty master (stdin_read)""" + if os.get_blocking(master_fd): + # If we write more than tty/ndisc is willing to buffer, we may block + # indefinitely. So we set master_fd to non-blocking temporarily during + # the copy operation. + os.set_blocking(master_fd, False) + try: + _copy(master_fd, master_read=master_read, stdin_read=stdin_read) + finally: + # restore blocking mode for backwards compatibility + os.set_blocking(master_fd, True) + return + high_waterlevel = 4096 + stdin_avail = master_fd != STDIN_FILENO + stdout_avail = master_fd != STDOUT_FILENO + i_buf = b'' + o_buf = b'' + while 1: + rfds = [] + wfds = [] + if stdin_avail and len(i_buf) < high_waterlevel: + rfds.append(STDIN_FILENO) + if stdout_avail and len(o_buf) < high_waterlevel: + rfds.append(master_fd) + if stdout_avail and len(o_buf) > 0: + wfds.append(STDOUT_FILENO) + if len(i_buf) > 0: + wfds.append(master_fd) + + rfds, wfds, _xfds = select(rfds, wfds, []) + + if STDOUT_FILENO in wfds: + try: + n = os.write(STDOUT_FILENO, o_buf) + o_buf = o_buf[n:] + except OSError: + stdout_avail = False + + if master_fd in rfds: + # Some OSes signal EOF by returning an empty byte string, + # some throw OSErrors. + try: + data = master_read(master_fd) + except OSError: + data = b"" + if not data: # Reached EOF. + return # Assume the child process has exited and is + # unreachable, so we clean up. + o_buf += data + + if master_fd in wfds: + n = os.write(master_fd, i_buf) + i_buf = i_buf[n:] + + if stdin_avail and STDIN_FILENO in rfds: + data = stdin_read(STDIN_FILENO) + if not data: + stdin_avail = False + else: + i_buf += data + +def spawn(argv, master_read=_read, stdin_read=_read): + """Create a spawned process.""" + if type(argv) == type(''): + argv = (argv,) + sys.audit('pty.spawn', argv) + + pid, master_fd = fork() + if pid == CHILD: + os.execlp(argv[0], *argv) + + try: + mode = tcgetattr(STDIN_FILENO) + setraw(STDIN_FILENO) + restore = True + except tty.error: # This is the same as termios.error + restore = False + + try: + _copy(master_fd, master_read, stdin_read) + finally: + if restore: + tcsetattr(STDIN_FILENO, tty.TCSAFLUSH, mode) + + close(master_fd) + return waitpid(pid, 0)[1] |