Synnefo » snf-image-creator

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"""This module hosts OS-specific code for Linux"""

from image_creator.os_type.unix import Unix, sysprep

import re

import time

class Linux(Unix):

    """OS class for Linux"""

    def __init__(self, image, **kargs):

        super(Linux, self).__init__(image, **kargs)

        self._uuid = dict()

        self._persistent = re.compile('/dev/[hsv]d[a-z][1-9]*')

    @sysprep('Removing user accounts with id greater that 1000', enabled=False)

    def remove_user_accounts(self):

        """Remove all user accounts with id greater than 1000"""

        if 'USERS' not in self.meta:

            return

        # Remove users from /etc/passwd

        passwd = []

        removed_users = {}

        metadata_users = self.meta['USERS'].split()

        for line in self.image.g.cat('/etc/passwd').splitlines():

            fields = line.split(':')

            if int(fields[2]) > 1000:

                removed_users[fields[0]] = fields

                # remove it from the USERS metadata too

                if fields[0] in metadata_users:

                    metadata_users.remove(fields[0])

            else:

                passwd.append(':'.join(fields))

        self.meta['USERS'] = " ".join(metadata_users)

        # Delete the USERS metadata if empty

        if not len(self.meta['USERS']):

            del self.meta['USERS']

        self.image.g.write('/etc/passwd', '\n'.join(passwd) + '\n')

        # Remove the corresponding /etc/shadow entries

        shadow = []

        for line in self.image.g.cat('/etc/shadow').splitlines():

            fields = line.split(':')

            if fields[0] not in removed_users:

                shadow.append(':'.join(fields))

        self.image.g.write('/etc/shadow', "\n".join(shadow) + '\n')

        # Remove the corresponding /etc/group entries

        group = []

        for line in self.image.g.cat('/etc/group').splitlines():

            fields = line.split(':')

            # Remove groups tha have the same name as the removed users

            if fields[0] not in removed_users:

                group.append(':'.join(fields))

        self.image.g.write('/etc/group', '\n'.join(group) + '\n')

        # Remove home directories

        for home in [field[5] for field in removed_users.values()]:

            if self.image.g.is_dir(home) and home.startswith('/home/'):

                self.image.g.rm_rf(home)

    @sysprep('Cleaning up password & locking all user accounts')

    def cleanup_passwords(self):

        """Remove all passwords and lock all user accounts"""

        shadow = []

        for line in self.image.g.cat('/etc/shadow').splitlines():

            fields = line.split(':')

            if fields[1] not in ('*', '!'):

                fields[1] = '!'

            shadow.append(":".join(fields))

        self.image.g.write('/etc/shadow', "\n".join(shadow) + '\n')

    @sysprep('Fixing acpid powerdown action')

    def fix_acpid(self):

        """Replace acpid powerdown action scripts to immediately shutdown the

        system without checking if a GUI is running.

        """

        powerbtn_action = '#!/bin/sh\n\nPATH=/sbin:/bin:/usr/bin\n' \

                          'shutdown -h now "Power button pressed"\n'

        events_dir = '/etc/acpi/events'

        if not self.image.g.is_dir(events_dir):

            self.out.warn("No acpid event directory found")

            return

        event_exp = re.compile('event=(.+)', re.I)

        action_exp = re.compile('action=(.+)', re.I)

        for events_file in self.image.g.readdir(events_dir):

            if events_file['ftyp'] != 'r':

                continue

            fullpath = "%s/%s" % (events_dir, events_file['name'])

            event = ""

            action = ""

            for line in self.image.g.cat(fullpath).splitlines():

                match = event_exp.match(line)

                if match:

                    event = match.group(1)

                    continue

                match = action_exp.match(line)

                if match:

                    action = match.group(1)

                    continue

            if event.strip() in ("button[ /]power", "button/power.*"):

                if action:

                    if not self.image.g.is_file(action):

                        self.out.warn("Acpid action file: %s does not exist" %

                                      action)

                        return

                    self.image.g.copy_file_to_file(action,

                                             "%s.orig.snf-image-creator-%d" %

                                             (action, time.time()))

                    self.image.g.write(action, powerbtn_action)

                    return

                else:

                    self.out.warn("Acpid event file %s does not contain and "

                                  "action")

                    return

            elif event.strip() == ".*":

                self.out.warn("Found action `.*'. Don't know how to handle "

                              "this. Please edit `%s' image file manually to "

                              "make the system immediatelly shutdown when an "

                              "power button acpi event occures." %

                              action.strip().split()[0])

                return

        self.out.warn("No acpi power button event found!")

    @sysprep('Removing persistent network interface names')

    def remove_persistent_net_rules(self):

        """Remove udev rules that will keep network interface names persistent

        after hardware changes and reboots. Those rules will be created again

        the next time the image runs.

        """

        rule_file = '/etc/udev/rules.d/70-persistent-net.rules'

        if self.image.g.is_file(rule_file):

            self.image.g.rm(rule_file)

    @sysprep('Removing swap entry from fstab')

    def remove_swap_entry(self):

        """Remove swap entry from /etc/fstab. If swap is the last partition

        then the partition will be removed when shrinking is performed. If the

        swap partition is not the last partition in the disk or if you are not

        going to shrink the image you should probably disable this.

        """

        new_fstab = ""

        fstab = self.image.g.cat('/etc/fstab')

        for line in fstab.splitlines():

            entry = line.split('#')[0].strip().split()

            if len(entry) == 6 and entry[2] == 'swap':

                continue

            new_fstab += "%s\n" % line

        self.image.g.write('/etc/fstab', new_fstab)

    @sysprep('Replacing fstab & grub non-persistent device references')

    def use_persistent_block_device_names(self):

        """Scan fstab & grub configuration files and replace all non-persistent

        device references with UUIDs.

        """

        # convert all devices in fstab to persistent

        persistent_root = self._persistent_fstab()

        # convert all devices in grub1 to persistent

        self._persistent_grub1(persistent_root)

    def _persistent_grub1(self, new_root):

        """Replaces non-persistent device name occurencies with persistent

        ones in GRUB1 configuration files.

        """

        if self.image.g.is_file('/boot/grub/menu.lst'):

            grub1 = '/boot/grub/menu.lst'

        elif self.image.g.is_file('/etc/grub.conf'):

            grub1 = '/etc/grub.conf'

        else:

            return

        self.image.g.aug_init('/', 0)

        try:

            roots = self.image.g.aug_match(

                '/files%s/title[*]/kernel/root' % grub1)

            for root in roots:

                dev = self.image.g.aug_get(root)

                if not self._is_persistent(dev):

                    # This is not always correct. Grub may contain root entries

                    # for other systems, but we only support 1 OS per hard

                    # disk, so this shouldn't harm.

                    self.image.g.aug_set(root, new_root)

        finally:

            self.image.g.aug_save()

            self.image.g.aug_close()

    def _persistent_fstab(self):

        """Replaces non-persistent device name occurencies in /etc/fstab with

        persistent ones.

        """

        mpoints = self.image.g.mountpoints()

        if len(mpoints) == 0:

            pass  # TODO: error handling

        device_dict = dict([[mpoint, dev] for dev, mpoint in mpoints])

        root_dev = None

        new_fstab = ""

        fstab = self.image.g.cat('/etc/fstab')

        for line in fstab.splitlines():

            line, dev, mpoint = self._convert_fstab_line(line, device_dict)

            new_fstab += "%s\n" % line

            if mpoint == '/':

                root_dev = dev

        self.image.g.write('/etc/fstab', new_fstab)

        if root_dev is None:

            pass  # TODO: error handling

        return root_dev

    def _convert_fstab_line(self, line, devices):

        """Replace non-persistent device names in an fstab line to their UUID

        equivalent

        """

        orig = line

        line = line.split('#')[0].strip()

        if len(line) == 0:

            return orig, "", ""

        entry = line.split()

        if len(entry) != 6:

            self.out.warn("Detected abnormal entry in fstab")

            return orig, "", ""

        dev = entry[0]

        mpoint = entry[1]

        if not self._is_persistent(dev):

            if mpoint in devices:

                dev = "UUID=%s" % self._get_uuid(devices[mpoint])

                entry[0] = dev

            else:

                # comment out the entry

                entry[0] = "#%s" % dev

            return " ".join(entry), dev, mpoint

        return orig, dev, mpoint

    def _do_collect_metadata(self):

        """Collect metadata about the OS"""

        super(Linux, self)._do_collect_metadata()

        self.meta["USERS"] = " ".join(self._get_passworded_users())

        # Delete the USERS metadata if empty

        if not len(self.meta['USERS']):

            self.out.warn("No passworded users found!")

            del self.meta['USERS']

    def _get_passworded_users(self):

        """Returns a list of non-locked user accounts"""

        users = []

        regexp = re.compile(r'(\S+):((?:!\S+)|(?:[^!*]\S+)|):(?:\S*:){6}')

        for line in self.image.g.cat('/etc/shadow').splitlines():

            match = regexp.match(line)

            if not match:

                continue

            user, passwd = match.groups()

            if len(passwd) > 0 and passwd[0] == '!':

                self.out.warn("Ignoring locked %s account." % user)

            else:

                users.append(user)

        return users

    def _is_persistent(self, dev):

        """Checks if a device name is persistent."""

        return not self._persistent.match(dev)

    def _get_uuid(self, dev):

        """Returns the UUID corresponding to a device"""

        if dev in self._uuid:

            return self._uuid[dev]

        uuid = self.image.g.vfs_uuid(dev)

        assert len(uuid)

        self._uuid[dev] = uuid

        return uuid

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