#!/usr/bin/env python
#
# $Id$
# 
# Copyright (C) 2014  Dragon Research Labs ("DRL")
# Portions copyright (C) 2013  Internet Systems Consortium ("ISC")
# 
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notices and this permission notice appear in all copies.
# 
# THE SOFTWARE IS PROVIDED "AS IS" AND DRL AND ISC DISCLAIM ALL
# WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL DRL OR
# ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
# DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA
# OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
# TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
# PERFORMANCE OF THIS SOFTWARE.

"""
Cron job for rcynic and rtr-origin in stock configuration.

Locking code here works like FreeBSD's lockf(1) utility given -k and
-t 0 options, which is both the sanest and simplest combination for
our purposes.  In theory this is portable to any Unix-like system.
"""

import os
import sys
import pwd
import fcntl
import errno
import argparse
import rpki.autoconf

def run(*cmd, **kwargs):
  chroot_this = kwargs.pop("chroot_this", False)
  cwd = kwargs.pop("cwd", None)
  pid = os.fork()
  if pid == 0:
    if chroot_this:
      os.chdir(rpki.autoconf.RCYNIC_DIR)
    elif cwd is not None:
      os.chdir(cwd)
    if we_are_root:
      os.initgroups(pw.pw_name, pw.pw_gid)
    if chroot_this:
      os.chroot(rpki.autoconf.RCYNIC_DIR)
    if we_are_root:
      os.setgid(pw.pw_gid)
      os.setuid(pw.pw_uid)
    os.closerange(3, os.sysconf("SC_OPEN_MAX"))
    os.execvp(cmd[0], cmd)
    os._exit(1)
  else:
    status = os.waitpid(pid, 0)[1]
    if status == 0:
      return
    elif os.WIFSIGNALED(status):
      sys.exit("Process %s exited with signal %s" % (" ".join(cmd), os.WTERMSIG(status)))
    elif os.WIFEXITED(status):
      sys.exit("Program %s exited with status %s" % (" ".join(cmd), os.WEXITSTATUS(status)))
    else:
      sys.exit("Program %s exited for unknown reason %s" % (" ".join(cmd), status))

parser = argparse.ArgumentParser(description = __doc__)
parser.add_argument("--chroot", action = "store_true", help = "run chrooted")
args = parser.parse_args()

we_are_root = os.getuid() == 0

if args.chroot and not we_are_root:
  sys.exit("Only root can --chroot")

try:
  pw = pwd.getpwnam(rpki.autoconf.RCYNIC_USER)
except KeyError:
  sys.exit("Could not find passwd entry for user %s" % rpki.autoconf.RCYNIC_USER)

try:
  lock = os.open(os.path.join(rpki.autoconf.RCYNIC_DIR, "data/lock"),
                 os.O_RDONLY | os.O_CREAT | os.O_NONBLOCK, 0666)
  fcntl.flock(lock, fcntl.LOCK_EX | fcntl.LOCK_NB)
  if we_are_root:
    os.fchown(lock, pw.pw_uid, pw.pw_gid)
except (IOError, OSError), e:
  if e.errno == errno.EAGAIN:
    sys.exit(0)                         # Another instance of this script is already running, exit silently
  else:
    sys.exit("Error %r opening lock %r" % (e.strerror, os.path.join(rpki.autoconf.RCYNIC_DIR, "data/lock")))

if args.chroot:
  run("/bin/rcynic", "-c", "/etc/rcynic.conf", chroot_this = True)
else:
  run(os.path.join(rpki.autoconf.bindir, "rcynic"), "-c", os.path.join(rpki.autoconf.sysconfdir, "rcynic.conf"))

run(os.path.join(rpki.autoconf.bindir, "rtr-origin"),
    "--cronjob", 
    os.path.join(rpki.autoconf.RCYNIC_DIR, "data/authenticated"),
    cwd = os.path.join(rpki.autoconf.RCYNIC_DIR, "rpki-rtr"))

prog = os.path.join(rpki.autoconf.libexecdir, "rpkigui-rcynic")
if os.path.exists(prog):
  run(prog)

if rpki.autoconf.RCYNIC_HTML_DIR and os.path.exists(os.path.dirname(rpki.autoconf.RCYNIC_HTML_DIR)):
  run(os.path.join(rpki.autoconf.bindir, "rcynic-html"),
      os.path.join(rpki.autoconf.RCYNIC_DIR, "data/rcynic.xml"),
      rpki.autoconf.RCYNIC_HTML_DIR)