# Copyright (C) 2009-2010 Canonical Ltd.

# Copyright (C) 2012 Hewlett-Packard Development Company, L.P.

#

# Author: Scott Moser <scott.moser@canonical.com>

# Author: Juerg Haefliger <juerg.haefliger@hp.com>

#

# This file is part of cloud-init. See LICENSE file for license information.

"""

Mounts

------

**Summary:** configure mount points and swap files

This module can add or remove mountpoints from ``/etc/fstab`` as well as

configure swap. The ``mounts`` config key takes a list of fstab entries to add.

Each entry is specified as a list of ``[ fs_spec, fs_file, fs_vfstype,

fs_mntops, fs-freq, fs_passno ]``. For more information on these options,

consult the manual for ``/etc/fstab``. When specifying the ``fs_spec``, if the

device name starts with one of ``xvd``, ``sd``, ``hd``, or ``vd``, the leading

``/dev`` may be omitted.

In order to remove a previously listed mount, an entry can be added to the

mounts list containing ``fs_spec`` for the device to be removed but no

mountpoint (i.e. ``[ sda1 ]`` or ``[ sda1, null ]``).

The ``mount_default_fields`` config key allows default options to be specified

for the values in a ``mounts`` entry that are not specified, aside from the

``fs_spec`` and the ``fs_file``. If specified, this must be a list containing 6

values. It defaults to::

    mount_default_fields: [none, none, "auto", "defaults,nobootwait", "0", "2"]

On a systemd booted system that default is the mostly equivalent::

    mount_default_fields: [none, none, "auto",

       "defaults,nofail,x-systemd.requires=cloud-init.service", "0", "2"]

Note that `nobootwait` is an upstart specific boot option that somewhat

equates to the more standard `nofail`.

Swap files can be configured by setting the path to the swap file to create

with ``filename``, the size of the swap file with ``size`` maximum size of

the swap file if using an ``size: auto`` with ``maxsize``. By default no

swap file is created.

**Internal name:** ``cc_mounts``

**Module frequency:** per instance

**Supported distros:** all

**Config keys**::

    mounts:

        - [ /dev/ephemeral0, /mnt, auto, "defaults,noexec" ]

        - [ sdc, /opt/data ]

        - [ xvdh, /opt/data, "auto", "defaults,nofail", "0", "0" ]

    mount_default_fields: [None, None, "auto", "defaults,nofail", "0", "2"]

    swap:

        filename: <file>

        size: <"auto"/size in bytes>

        maxsize: <size in bytes>

"""

from string import whitespace

import logging

import os

import re

from cloudinit import type_utils

from cloudinit import subp

from cloudinit import util

# Shortname matches 'sda', 'sda1', 'xvda', 'hda', 'sdb', xvdb, vda, vdd1, sr0

DEVICE_NAME_FILTER = r"^([x]{0,1}[shv]d[a-z][0-9]*|sr[0-9]+)$"

DEVICE_NAME_RE = re.compile(DEVICE_NAME_FILTER)

# Name matches 'server:/path'

NETWORK_NAME_FILTER = r"^.+:.*"

NETWORK_NAME_RE = re.compile(NETWORK_NAME_FILTER)

WS = re.compile("[%s]+" % (whitespace))

FSTAB_PATH = "/etc/fstab"

MNT_COMMENT = "comment=cloudconfig"

LOG = logging.getLogger(__name__)

def is_meta_device_name(name):

    # return true if this is a metadata service name

    if name in ["ami", "root", "swap"]:

        return True

    # names 'ephemeral0' or 'ephemeral1'

    # 'ebs[0-9]' appears when '--block-device-mapping sdf=snap-d4d90bbc'

    for enumname in ("ephemeral", "ebs"):

        if name.startswith(enumname) and name.find(":") == -1:

            return True

    return False

def is_network_device(name):

    # return true if this is a network device

    if NETWORK_NAME_RE.match(name):

        return True

    return False

def _get_nth_partition_for_device(device_path, partition_number):

    potential_suffixes = [str(partition_number), 'p%s' % (partition_number,),

                          '-part%s' % (partition_number,)]

    for suffix in potential_suffixes:

        potential_partition_device = '%s%s' % (device_path, suffix)

        if os.path.exists(potential_partition_device):

            return potential_partition_device

    return None

def _is_block_device(device_path, partition_path=None):

    device_name = os.path.realpath(device_path).split('/')[-1]

    sys_path = os.path.join('/sys/block/', device_name)

    if partition_path is not None:

        sys_path = os.path.join(

            sys_path, os.path.realpath(partition_path).split('/')[-1])

    return os.path.exists(sys_path)

def sanitize_devname(startname, transformer, log):

    log.debug("Attempting to determine the real name of %s", startname)

    # workaround, allow user to specify 'ephemeral'

    # rather than more ec2 correct 'ephemeral0'

    devname = startname

    if devname == "ephemeral":

        devname = "ephemeral0"

        log.debug("Adjusted mount option from ephemeral to ephemeral0")

    if is_network_device(startname):

        return startname

    device_path, partition_number = util.expand_dotted_devname(devname)

    if is_meta_device_name(device_path):

        orig = device_path

        device_path = transformer(device_path)

        if not device_path:

            return None

        if not device_path.startswith("/"):

            device_path = "/dev/%s" % (device_path,)

        log.debug("Mapped metadata name %s to %s", orig, device_path)

    else:

        if DEVICE_NAME_RE.match(startname):

            device_path = "/dev/%s" % (device_path,)

    partition_path = None

    if partition_number is None:

        partition_path = _get_nth_partition_for_device(device_path, 1)

    else:

        partition_path = _get_nth_partition_for_device(device_path,

                                                       partition_number)

        if partition_path is None:

            return None

    if _is_block_device(device_path, partition_path):

        if partition_path is not None:

            return partition_path

        return device_path

    return None

def suggested_swapsize(memsize=None, maxsize=None, fsys=None):

    # make a suggestion on the size of swap for this system.

    if memsize is None:

        memsize = util.read_meminfo()['total']

    GB = 2 ** 30

    sugg_max = 8 * GB

    info = {'avail': 'na', 'max_in': maxsize, 'mem': memsize}

    if fsys is None and maxsize is None:

        # set max to 8GB default if no filesystem given

        maxsize = sugg_max

    elif fsys:

        statvfs = os.statvfs(fsys)

        avail = statvfs.f_frsize * statvfs.f_bfree

        info['avail'] = avail

        if maxsize is None:

            # set to 25% of filesystem space

            maxsize = min(int(avail / 4), sugg_max)

        elif maxsize > ((avail * .9)):

            # set to 90% of available disk space

            maxsize = int(avail * .9)

    elif maxsize is None:

        maxsize = sugg_max

    info['max'] = maxsize

    formulas = [

        # < 1G: swap = double memory

        (1 * GB, lambda x: x * 2),

        # < 2G: swap = 2G

        (2 * GB, lambda x: 2 * GB),

        # < 4G: swap = memory

        (4 * GB, lambda x: x),

        # < 16G: 4G

        (16 * GB, lambda x: 4 * GB),

        # < 64G: 1/2 M up to max

        (64 * GB, lambda x: x / 2),

    ]

    size = None

    for top, func in formulas:

        if memsize <= top:

            size = min(func(memsize), maxsize)

            # if less than 1/2 memory and not much, return 0

            if size < (memsize / 2) and size < 4 * GB:

                size = 0

                break

            break

    if size is not None:

        size = maxsize

    info['size'] = size

    MB = 2 ** 20

    pinfo = {}

    for k, v in info.items():

        if isinstance(v, int):

            pinfo[k] = "%s MB" % (v / MB)

        else:

            pinfo[k] = v

    LOG.debug("suggest %s swap for %s memory with '%s'"

              " disk given max=%s [max=%s]'", pinfo['size'], pinfo['mem'],

              pinfo['avail'], pinfo['max_in'], pinfo['max'])

    return size

def create_swapfile(fname: str, size: str) -> None:

    """Size is in MiB."""

    errmsg = "Failed to create swapfile '%s' of size %sMB via %s: %s"

    def create_swap(fname, size, method):

        LOG.debug("Creating swapfile in '%s' on fstype '%s' using '%s'",

                  fname, fstype, method)

        if method == "fallocate":

            cmd = ['fallocate', '-l', '%sM' % size, fname]

        elif method == "dd":

            cmd = ['dd', 'if=/dev/zero', 'of=%s' % fname, 'bs=1M',

                   'count=%s' % size]

        try:

            subp.subp(cmd, capture=True)

        except subp.ProcessExecutionError as e:

            LOG.warning(errmsg, fname, size, method, e)

            util.del_file(fname)

    swap_dir = os.path.dirname(fname)

    util.ensure_dir(swap_dir)

    fstype = util.get_mount_info(swap_dir)[1]

    if (fstype == "xfs" and

            util.kernel_version() < (4, 18)) or fstype == "btrfs":

        create_swap(fname, size, "dd")

    else:

        try:

            create_swap(fname, size, "fallocate")

        except subp.ProcessExecutionError as e:

            LOG.warning(errmsg, fname, size, "dd", e)

            LOG.warning("Will attempt with dd.")

            create_swap(fname, size, "dd")

    if os.path.exists(fname):

        util.chmod(fname, 0o600)

    try:

        subp.subp(['mkswap', fname])

    except subp.ProcessExecutionError:

        util.del_file(fname)

        raise

def setup_swapfile(fname, size=None, maxsize=None):

    """

    fname: full path string of filename to setup

    size: the size to create. set to "auto" for recommended

    maxsize: the maximum size

    """

    swap_dir = os.path.dirname(fname)

    if str(size).lower() == "auto":

        try:

            memsize = util.read_meminfo()['total']

        except IOError:

            LOG.debug("Not creating swap: failed to read meminfo")

            return

        util.ensure_dir(swap_dir)

        size = suggested_swapsize(fsys=swap_dir, maxsize=maxsize,

                                  memsize=memsize)

    mibsize = str(int(size / (2 ** 20)))

    if not size:

        LOG.debug("Not creating swap: suggested size was 0")

        return

    util.log_time(LOG.debug, msg="Setting up swap file", func=create_swapfile,

                  args=[fname, mibsize])

    return fname

def handle_swapcfg(swapcfg):

    """handle the swap config, calling setup_swap if necessary.

       return None or (filename, size)

    """

    if not isinstance(swapcfg, dict):

        LOG.warning("input for swap config was not a dict.")

        return None

    fname = swapcfg.get('filename', '/swap.img')

    size = swapcfg.get('size', 0)

    maxsize = swapcfg.get('maxsize', None)

    if not (size and fname):

        LOG.debug("no need to setup swap")

        return

    if os.path.exists(fname):

        if not os.path.exists("/proc/swaps"):

            LOG.debug("swap file %s exists, but no /proc/swaps exists, "

                      "being safe", fname)

            return fname

        try:

            for line in util.load_file("/proc/swaps").splitlines():

                if line.startswith(fname + " "):

                    LOG.debug("swap file %s already in use", fname)

                    return fname

            LOG.debug("swap file %s exists, but not in /proc/swaps", fname)

        except Exception:

            LOG.warning("swap file %s exists. Error reading /proc/swaps",

                        fname)

            return fname

    try:

        if isinstance(size, str) and size != "auto":

            size = util.human2bytes(size)

        if isinstance(maxsize, str):

            maxsize = util.human2bytes(maxsize)

        return setup_swapfile(fname=fname, size=size, maxsize=maxsize)

    except Exception as e:

        LOG.warning("failed to setup swap: %s", e)

    return None

def handle(_name, cfg, cloud, log, _args):

    # fs_spec, fs_file, fs_vfstype, fs_mntops, fs-freq, fs_passno

    def_mnt_opts = "defaults,nobootwait"

    uses_systemd = cloud.distro.uses_systemd()

    if uses_systemd:

        def_mnt_opts = "defaults,nofail,x-systemd.requires=cloud-init.service"

    defvals = [None, None, "auto", def_mnt_opts, "0", "2"]

    defvals = cfg.get("mount_default_fields", defvals)

    # these are our default set of mounts

    defmnts = [["ephemeral0", "/mnt", "auto", defvals[3], "0", "2"],

               ["swap", "none", "swap", "sw", "0", "0"]]

    cfgmnt = []

    if "mounts" in cfg:

        cfgmnt = cfg["mounts"]

    LOG.debug("mounts configuration is %s", cfgmnt)

    fstab_lines = []

    fstab_devs = {}

    fstab_removed = []

    if os.path.exists(FSTAB_PATH):

        for line in util.load_file(FSTAB_PATH).splitlines():

            if MNT_COMMENT in line:

                fstab_removed.append(line)

                continue

            try:

                toks = WS.split(line)

            except Exception:

                pass

            fstab_devs[toks[0]] = line

            fstab_lines.append(line)

    for i in range(len(cfgmnt)):

        # skip something that wasn't a list

        if not isinstance(cfgmnt[i], list):

            log.warning("Mount option %s not a list, got a %s instead",

                        (i + 1), type_utils.obj_name(cfgmnt[i]))

            continue

        start = str(cfgmnt[i][0])

        sanitized = sanitize_devname(start, cloud.device_name_to_device, log)

        if sanitized != start:

            log.debug("changed %s => %s" % (start, sanitized))

        if sanitized is None:

            log.debug("Ignoring nonexistent named mount %s", start)

            continue

        elif sanitized in fstab_devs:

            log.info("Device %s already defined in fstab: %s",

                     sanitized, fstab_devs[sanitized])

            continue

        cfgmnt[i][0] = sanitized

        # in case the user did not quote a field (likely fs-freq, fs_passno)

        # but do not convert None to 'None' (LP: #898365)

        for j in range(len(cfgmnt[i])):

            if cfgmnt[i][j] is None:

                continue

            else:

                cfgmnt[i][j] = str(cfgmnt[i][j])

    for i in range(len(cfgmnt)):

        # fill in values with defaults from defvals above

        for j in range(len(defvals)):

            if len(cfgmnt[i]) <= j:

                cfgmnt[i].append(defvals[j])

            elif cfgmnt[i][j] is None:

                cfgmnt[i][j] = defvals[j]

        # if the second entry in the list is 'None' this

        # clears all previous entries of that same 'fs_spec'

        # (fs_spec is the first field in /etc/fstab, ie, that device)

        if cfgmnt[i][1] is None:

            for j in range(i):

                if cfgmnt[j][0] == cfgmnt[i][0]:

                    cfgmnt[j][1] = None

    # for each of the "default" mounts, add them only if no other

    # entry has the same device name

    for defmnt in defmnts:

        start = defmnt[0]

        sanitized = sanitize_devname(start, cloud.device_name_to_device, log)

        if sanitized != start:

            log.debug("changed default device %s => %s" % (start, sanitized))

        if sanitized is None:

            log.debug("Ignoring nonexistent default named mount %s", start)

            continue

        elif sanitized in fstab_devs:

            log.debug("Device %s already defined in fstab: %s",

                      sanitized, fstab_devs[sanitized])

            continue

        defmnt[0] = sanitized

        cfgmnt_has = False

        for cfgm in cfgmnt:

            if cfgm[0] == defmnt[0]:

                cfgmnt_has = True

                break

        if cfgmnt_has:

            log.debug(("Not including %s, already"

                       " previously included"), start)

            continue

        cfgmnt.append(defmnt)

    # now, each entry in the cfgmnt list has all fstab values

    # if the second field is None (not the string, the value) we skip it

    actlist = []

    for x in cfgmnt:

        if x[1] is None:

            log.debug("Skipping nonexistent device named %s", x[0])

        else:

            actlist.append(x)

    swapret = handle_swapcfg(cfg.get('swap', {}))

    if swapret:

        actlist.append([swapret, "none", "swap", "sw", "0", "0"])

    if len(actlist) == 0:

        log.debug("No modifications to fstab needed")

        return

    cc_lines = []

    needswap = False

    need_mount_all = False

    dirs = []

    for line in actlist:

        # write 'comment' in the fs_mntops, entry,  claiming this

        line[3] = "%s,%s" % (line[3], MNT_COMMENT)

        if line[2] == "swap":

            needswap = True

        if line[1].startswith("/"):

            dirs.append(line[1])

        cc_lines.append('\t'.join(line))

    mount_points = [v['mountpoint'] for k, v in util.mounts().items()

                    if 'mountpoint' in v]

    for d in dirs:

        try:

            util.ensure_dir(d)

        except Exception:

            util.logexc(log, "Failed to make '%s' config-mount", d)

        # dirs is list of directories on which a volume should be mounted.

        # If any of them does not already show up in the list of current

        # mount points, we will definitely need to do mount -a.

        if not need_mount_all and d not in mount_points:

            need_mount_all = True

    sadds = [WS.sub(" ", n) for n in cc_lines]

    sdrops = [WS.sub(" ", n) for n in fstab_removed]

    sops = (["- " + drop for drop in sdrops if drop not in sadds] +

            ["+ " + add for add in sadds if add not in sdrops])

    fstab_lines.extend(cc_lines)

    contents = "%s\n" % ('\n'.join(fstab_lines))

    util.write_file(FSTAB_PATH, contents)

    activate_cmds = []

    if needswap:

        activate_cmds.append(["swapon", "-a"])

    if len(sops) == 0:

        log.debug("No changes to /etc/fstab made.")

    else:

        log.debug("Changes to fstab: %s", sops)

        need_mount_all = True

    if need_mount_all:

        activate_cmds.append(["mount", "-a"])

        if uses_systemd:

            activate_cmds.append(["systemctl", "daemon-reload"])

    fmt = "Activating swap and mounts with: %s"

    for cmd in activate_cmds:

        fmt = "Activate mounts: %s:" + ' '.join(cmd)

        try:

            subp.subp(cmd)

            log.debug(fmt, "PASS")

        except subp.ProcessExecutionError:

            log.warning(fmt, "FAIL")

            util.logexc(log, fmt, "FAIL")

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