#!/usr/bin/python2
#
# The Qubes OS Project, http://www.qubes-os.org
#
# Copyright (C) 2010  Joanna Rutkowska <joanna@invisiblethingslab.com>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
#
#

from qubes.qubes import QubesVmCollection
from qubes.qubes import QubesException
from qubes.backup import backup_prepare, backup_do
from qubes.qubesutils import size_to_human
from optparse import OptionParser
import os
import sys
import getpass

def print_progress(progress):
    print >> sys.stderr, "\r-> Backing up files: {0}%...".format (progress),

def main():
    usage = "usage: %prog [options] <backup-dir-path> [vms-to-be-included ...]"
    parser = OptionParser (usage)

    parser.add_option ("-x", "--exclude", action="append",
                       dest="exclude_list", default=[],
                       help="Exclude the specified VM from backup (may be "
                            "repeated)")
    parser.add_option ("--force-root", action="store_true", dest="force_root", default=False,
                       help="Force to run, even with root privileges")
    parser.add_option ("-d", "--dest-vm", action="store", dest="appvm",
                       help="The AppVM to send backups to (implies -e)")
    parser.add_option ("-e", "--encrypt", action="store_true", dest="encrypt", default=False,
                       help="Encrypts the backup")
    parser.add_option ("-E", "--enc-algo", action="store",
                       dest="crypto_algorithm", default=None,
                       help="Specify non-default encryption algorithm. For "
                            "list of supported algos execute 'openssl "
                            "list-cipher-algorithms' (implies -e)")
    parser.add_option ("-H", "--hmac-algo", action="store",
                       dest="hmac_algorithm", default=None,
                       help="Specify non-default hmac algorithm. For list of "
                            "supported algos execute 'openssl "
                            "list-message-digest-algorithms'")
    parser.add_option ("-z", "--compress", action="store_true", dest="compress", default=False,
                       help="Compress the backup")

    (options, args) = parser.parse_args ()

    if (len (args) < 1):
        print >> sys.stderr, "You must specify the target backup directory (e.g. /mnt/backup)"
        print >> sys.stderr, "qvm-backup will create a subdirectory there for each individual backup."
        exit (0)

    base_backup_dir = args[0]

    if os.geteuid() == 0:
        if not options.force_root:
            print >> sys.stderr, "*** Running this tool as root is strongly discouraged, this will lead you in permissions problems."
            print >> sys.stderr, "Retry as unprivileged user."
            print >> sys.stderr, "... or use --force-root to continue anyway."
            exit(1)

    # Only for locking
    qvm_collection = QubesVmCollection()
    qvm_collection.lock_db_for_reading()
    qvm_collection.load()

    vms = None
    if (len (args) > 1):
        vms = [qvm_collection.get_vm_by_name(vmname) for vmname in args[1:]]

    if options.appvm:
        print >>sys.stderr, ("WARNING: VM {} excluded because it's used to "
                            "store the backup.").format(options.appvm)
        options.exclude_list.append(options.appvm)

    if options.appvm or options.crypto_algorithm:
        options.encrypt = True
    files_to_backup = None
    try:
        files_to_backup = backup_prepare(
                vms_list=vms,
                exclude_list=options.exclude_list,
                hide_vm_names=options.encrypt)
    except QubesException as e:
        print >>sys.stderr, "ERROR: %s" % str(e)
        exit(1)

    total_backup_sz = reduce(lambda size, file: size+file["size"],
            files_to_backup, 0)

    if not options.appvm:
        appvm = None

        stat = os.statvfs(base_backup_dir)
        backup_fs_free_sz = stat.f_bsize * stat.f_bavail
        print
        if (total_backup_sz > backup_fs_free_sz):
            print >>sys.stderr, "ERROR: Not enough space available on the backup filesystem!"
            exit(1)

        print "-> Available space: {0}".format(size_to_human(backup_fs_free_sz))
    else:
        appvm = qvm_collection.get_vm_by_name(options.appvm)
        if appvm is None:
            print >>sys.stderr, "ERROR: VM {0} does not exist".format(options.appvm)
            exit(1)

        stat = os.statvfs('/var/tmp')
        backup_fs_free_sz = stat.f_bsize * stat.f_bavail
        print
        if (backup_fs_free_sz < 1000000000):
            print >>sys.stderr, "ERROR: Not enough space available " \
                "on the local filesystem (needs 1GB for temporary files)!"
            exit(1)

        if not appvm.is_running():
            appvm.start(verbose=True)

    prompt = raw_input ("Do you want to proceed? [y/N] ")
    if not (prompt == "y" or prompt == "Y"):
        exit (0)

    passphrase = getpass.getpass("Please enter the pass phrase that will be used to encrypt/verify the backup: ")
    passphrase2 = getpass.getpass("Enter again for verification: ")
    if passphrase != passphrase2:
        print >>sys.stderr, "ERROR: Password mismatch"
        exit(1)

    kwargs = {}
    if options.hmac_algorithm:
        kwargs['hmac_algorithm'] = options.hmac_algorithm
    if options.crypto_algorithm:
        kwargs['crypto_algorithm'] = options.crypto_algorithm

    try:
        backup_do(base_backup_dir, files_to_backup, passphrase,
                progress_callback=print_progress,
                encrypted=options.encrypt,
                compressed=options.compress,
                appvm=appvm, **kwargs)
    except QubesException as e:
        print >>sys.stderr, "ERROR: %s" % str(e)
        exit(1)

    print
    print "-> Backup completed."

    qvm_collection.unlock_db()
main()