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authornkozlovskiy <nmk@ydb.tech>2023-09-29 12:24:06 +0300
committernkozlovskiy <nmk@ydb.tech>2023-09-29 12:41:34 +0300
commite0e3e1717e3d33762ce61950504f9637a6e669ed (patch)
treebca3ff6939b10ed60c3d5c12439963a1146b9711 /contrib/tools/python3/src/Lib/pty.py
parent38f2c5852db84c7b4d83adfcb009eb61541d1ccd (diff)
downloadydb-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.py217
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diff --git a/contrib/tools/python3/src/Lib/pty.py b/contrib/tools/python3/src/Lib/pty.py
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+++ b/contrib/tools/python3/src/Lib/pty.py
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+"""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]