lib/bup/ssh.py

   1 """SSH connection.
   2 Connect to a remote host via SSH and execute a command on the host.
   3 """
   4
   5 from __future__ import absolute_import, print_function
   6 import sys, os, re, subprocess
   7
   8 from bup import helpers, path
   9 from bup.compat import environ
  10
  11 def connect(rhost, port, subcmd, stderr=None):
  12     """Connect to 'rhost' and execute the bup subcommand 'subcmd' on it."""
  13     assert not re.search(br'[^\w-]', subcmd)
  14     if rhost is None or rhost == b'-':
  15         argv = [path.exe(), subcmd]
  16     else:
  17         buglvl = helpers.atoi(environ.get(b'BUP_DEBUG'))
  18         force_tty = helpers.atoi(environ.get(b'BUP_FORCE_TTY'))
  19         tty_width = helpers.atoi(environ.get(b'BUP_TTY_WIDTH'))
  20         cmd = b"""
  21                    sh -c 'BUP_DEBUG=%d BUP_FORCE_TTY=%d BUP_TTY_WIDTH=%d bup %s'
  22                """ % (buglvl, force_tty, tty_width, subcmd)
  23         argv = [b'ssh']
  24         if port:
  25             argv.extend((b'-p', port))
  26         argv.extend((rhost, b'--', cmd.strip()))
  27         #helpers.log('argv is: %r\n' % argv)
  28     if sys.version_info[0] < 3:
  29         return subprocess.Popen(argv,
  30                                 stdin=subprocess.PIPE, stdout=subprocess.PIPE,
  31                                 stderr=stderr,
  32                                 preexec_fn=lambda: os.setsid())
  33     else:
  34         return subprocess.Popen(argv,
  35                                 stdin=subprocess.PIPE, stdout=subprocess.PIPE,
  36                                 stderr=stderr,
  37                                 start_new_session=True)