diskutil.py

# SPDX-License-Identifier: GPL-2.0-only

import re, sys
import os.path
import errno
import constants
import fcntl
import glob
import util
import netutil
from util import dev_null
import xcp.logger as logger
from disktools import *
import time
from snackutil import ButtonChoiceWindowEx

use_mpath = False
CDROM_GET_CAPABILITY = 0x5331
IBFT_BLOCK_VALID_FLAG = 1 << 0

def mpath_cli_is_working():
    regex = re.compile("switchgroup")
    try:
        (rc,stdout) = util.runCmd2(["multipathd","-k"], with_stdout=True, inputtext="help")
        m=regex.search(stdout)
        return bool(m)
    except:
        return False

def wait_for_multipathd():
    for i in range(0,120):
        if mpath_cli_is_working():
            return
        time.sleep(1)
    msg = "Unable to contact Multipathd daemon"
    logger.log(msg)
    raise Exception(msg)

def mpath_part_scan(force=False):
    global use_mpath

    if not force and not use_mpath:
        return 0
    ret = createMpathPartnodes()
    if ret == 0:
         util.runCmd2(util.udevsettleCmd())
    return ret

def mpath_enable():
    global use_mpath
    assert 0 == util.runCmd2(['modprobe','dm-multipath'])

    if not os.path.exists('/etc/multipath.conf') and os.path.exists('/etc/multipath.conf.disabled'):
        os.rename('/etc/multipath.conf.disabled', '/etc/multipath.conf')

    # launch manually to make possible to wait initialization
    util.runCmd2(["/sbin/multipath", "-v0", "-B"])
    time.sleep(1)
    util.runCmd2(util.udevsettleCmd())

    # This creates maps for all disks at start of day (because -e is ommitted)
    assert 0 == util.runCmd2('multipathd -d > /var/log/multipathd 2>&1 &')
    wait_for_multipathd()
    # CA-48440: Cope with lost udev events
    util.runCmd2(["multipathd","-k"], inputtext="reconfigure")

    # Tell DM to create partition nodes for newly created mpath devices
    assert 0 == mpath_part_scan(True)
    logger.log("created multipath device(s)");
    use_mpath = True

def mpath_disable():
    destroyMpathPartnodes()
    util.runCmd2(['killall','multipathd'])
    util.runCmd2(['/sbin/multipath','-F'])
    use_mpath = False

# hd* -> (ide has majors 3, 22, 33, 34, 56, 57, 88, 89, 90, 91, each major has
# two disks, with minors 0... and 64...)
ide_majors = [ 3, 22, 33, 34, 56, 57, 88, 89, 90, 91 ]
disk_nodes  = [ (x, 0) for x in ide_majors ]
disk_nodes += [ (x, 64) for x in ide_majors ]

# sd* -> (sd-mod has majors 8, 65 ... 71, 128 ... 135: each device has eight minors, each
# major has sixteen disks).
# Extended minors are used for disk 257 and above and the major number wraps back to 8
# thus disk 257 is major 8 minor 256, disk 258 is
disk_nodes += [ (8, x * 16) for x in range(16) ]
disk_nodes += [ (65, x * 16) for x in range(16) ]
disk_nodes += [ (66, x * 16) for x in range(16) ]
disk_nodes += [ (67, x * 16) for x in range(16) ]
disk_nodes += [ (68, x * 16) for x in range(16) ]
disk_nodes += [ (69, x * 16) for x in range(16) ]
disk_nodes += [ (70, x * 16) for x in range(16) ]
disk_nodes += [ (71, x * 16) for x in range(16) ]
disk_nodes += [ (128, x * 16) for x in range(16) ]
disk_nodes += [ (129, x * 16) for x in range(16) ]
disk_nodes += [ (130, x * 16) for x in range(16) ]
disk_nodes += [ (131, x * 16) for x in range(16) ]
disk_nodes += [ (132, x * 16) for x in range(16) ]
disk_nodes += [ (133, x * 16) for x in range(16) ]
disk_nodes += [ (134, x * 16) for x in range(16) ]
disk_nodes += [ (135, x * 16) for x in range(16) ]

# xvd* -> (blkfront has major 202: each device has 15 minors)
disk_nodes += [ (202, x * 16) for x in range(16) ]

# /dev/cciss : c[0-7]d[0-15]: Compaq Next Generation Drive Array
# /dev/ida   : c[0-7]d[0-15]: Compaq Intelligent Drive Array
for major in list(range(72, 80)) + list(range(104, 112)):
    disk_nodes += [ (major, x * 16) for x in range(16) ]

# /dev/rd    : c[0-7]d[0-31]: Mylex DAC960 PCI RAID controller
for major in range(48, 56):
    disk_nodes += [ (major, x * 8) for x in range(32) ]

# /dev/mmcblk: mmcblk has major 179, each device usually (per kernel) has 7 minors
disk_nodes += [ (179, x * 8) for x in range(32) ]

def getDiskList():
    # read the partition tables:
    parts = open("/proc/partitions")
    partlines = [re.sub(" +", " ", x).strip() for x in parts.readlines()]
    parts.close()

    # parse it:
    disks = []
    for l in partlines:
        try:
            (major, minor, size, name) = l.split(" ")
            (major, minor, size) = (int(major), int(minor) % 256, int(size))
            if hasDeviceMapperHolder("/dev/" + name.replace("!","/")):
                # skip device that cannot be used
                continue
            if isDeviceMapperNode("/dev/" + name.replace("!","/")):
                # dm-* devices get added later as mapper/* devices
                continue
            if (major, minor) in disk_nodes:
                if major == 202 and isRemovable("/dev/" + name): # Ignore PV CDROM devices
                    continue
                disks.append(name.replace("!", "/"))
            # Handle LOCAL/EXPERIMENTAL and Block Extended Major devices
            if 240 <= major <= 254 or major == 259:
                rc, out = util.runCmd2(['/bin/lsblk', '-d', '-n', '-o', 'TYPE', "/dev/" + name.replace("!","/")],
                                       with_stdout=True)
                if rc == 0 and out.strip() not in ['part', 'md']:
                    disks.append(name.replace("!", "/"))

        except:
            # it wasn't an actual entry, maybe the headers or something:
            continue
    # Add multipath nodes to list
    disks.extend([node.replace('/dev/','') for node in getMpathNodes()])
    # Add md RAID nodes to list
    disks.extend([node.replace('/dev/','') for node in getMdNodes()])

    return disks

def getPartitionList():
    disks = getDiskList()
    rv  = []
    for disk in disks:
        rv.extend(partitionsOnDisk(disk))
    return rv

def partitionsOnDisk(disk):
    if disk.startswith('/dev/'):
        disk = disk[5:]
    if isDeviceMapperNode('/dev/' + disk):
        name = disk.split('/',1)[1]
        partitions = [s for s in os.listdir('/dev/mapper/') if re.match(name + r'p?\d+$', s)]
        partitions = ["mapper/%s" % s for s in partitions]
    else:
        name = disk.replace("/", "!")
        partitions = [s for s in os.listdir('/sys/block/%s' % name) if s.startswith(name)]
        partitions = [n.replace("!","/") for n in partitions]

    return partitions

def getQualifiedDiskList():
    return [getQualifiedDeviceName(x) for x in getDiskList()]

def getQualifiedPartitionList():
    return [getQualifiedDeviceName(x) for x in getPartitionList()]

def getRemovableDeviceList():
    devs = os.listdir('/sys/block')
    removable_devs = []
    for d in devs:
        if isRemovable(d):
            removable_devs.append(d.replace("!", "/"))

    return removable_devs

def removable(device):
    if device.startswith('/dev/'):
        device = device[5:]

    # CA-25624 - udev maps sr* to scd*
    if device.startswith('scd'):
        device = 'sr'+device[3:]

    return device in getRemovableDeviceList()

def getQualifiedDeviceName(disk):
    return "/dev/%s" % disk

# Given a partition (e.g. /dev/sda1), get the id symlink:
def idFromPartition(partition):
    symlink = None
    v, out = util.runCmd2(util.udevinfoCmd() + ['-q', 'symlink', '-n', partition], with_stdout=True)
    prefixes = ['disk/by-id/edd', 'disk/by-id/dm-name-', 'disk/by-id/dm-uuid-', 'disk/by-id/lvm-pv-uuid-', 'disk/by-id/cciss-']
    if v == 0:
        for link in out.split():
            if link.startswith('disk/by-id') and not True in [link.startswith(x) for x in prefixes]:
                symlink = '/dev/'+link
                break
    return symlink

# Given a id symlink (e.g. /dev/disk/by-id/scsi-...), get the device
def partitionFromId(symlink):
    return os.path.realpath(symlink)

def __readOneLineFile__(filename):
    try:
        f = open(filename)
        value = f.readline()
        f.close()
        return value
    except Exception as e:
        raise e

def getDiskDeviceVendor(dev):

    # For Multipath nodes return info about 1st slave
    if not dev.startswith("/dev/"):
        dev = '/dev/' + dev
    if isDeviceMapperNode(dev):
        return getDiskDeviceVendor(getDeviceSlaves(dev)[0])
    if is_raid(dev):
        vendors = set(map(getDiskDeviceVendor, getDeviceSlaves(dev)))
        return '/'.join(vendors)

    if dev.startswith("/dev/"):
        dev = re.match("/dev/(.*)", dev).group(1)
    dev = dev.replace("/", "!")
    if os.path.exists("/sys/block/%s/device/vendor" % dev):
        return __readOneLineFile__("/sys/block/%s/device/vendor" % dev).strip(' \n')
    else:
        return ""

def getDiskDeviceModel(dev):

    # For Multipath nodes return info about 1st slave
    if not dev.startswith("/dev/"):
        dev = '/dev/' + dev
    if isDeviceMapperNode(dev):
        return getDiskDeviceModel(getDeviceSlaves(dev)[0])
    if is_raid(dev):
        models = set(map(getDiskDeviceModel, getDeviceSlaves(dev)))
        return '/'.join(models)

    if dev.startswith("/dev/"):
        dev = re.match("/dev/(.*)", dev).group(1)
    dev = dev.replace("/", "!")
    if os.path.exists("/sys/block/%s/device/model" % dev):
        return __readOneLineFile__("/sys/block/%s/device/model" % dev).strip('  \n')
    else:
        return ""

def getDiskDeviceSize(dev):

    # For Multipath nodes return info about 1st slave
    if not dev.startswith("/dev/"):
        dev = '/dev/' + dev
    if isDeviceMapperNode(dev):
        return getDiskDeviceSize(getDeviceSlaves(dev)[0])

    if dev.startswith("/dev/"):
        dev = re.match("/dev/(.*)", dev).group(1)
    dev = dev.replace("/", "!")
    if os.path.exists("/sys/block/%s/device/block/size" % dev):
        return int(__readOneLineFile__("/sys/block/%s/device/block/size" % dev))
    elif os.path.exists("/sys/block/%s/size" % dev):
        return int(__readOneLineFile__("/sys/block/%s/size" % dev))

def getDiskBlockSize(dev):
    if not dev.startswith("/dev/"):
        dev = '/dev/' + dev
    if isDeviceMapperNode(dev):
        return getDiskBlockSize(getDeviceSlaves(dev)[0])
    if dev.startswith("/dev/"):
        dev = re.match("/dev/(.*)", dev).group(1)
    dev = dev.replace("/", "!")
    return int(__readOneLineFile__("/sys/block/%s/queue/logical_block_size"
                                   % dev))

def getDiskSerialNumber(dev):
    # For Multipath nodes return info about 1st slave
    if not dev.startswith("/dev/"):
        dev = '/dev/' + dev
    if isDeviceMapperNode(dev):
        return getDiskSerialNumber(getDeviceSlaves(dev)[0])
    if is_raid(dev):
        serials = set(map(getDiskSerialNumber, getDeviceSlaves(dev)))
        return '/'.join(serials)

    rc, out = util.runCmd2(['/bin/sdparm', '-q', '-i', '-p', 'sn', dev], with_stdout=True)
    if rc == 0:
        lines = out.split('\n')
        if len(lines) >= 2:
            return lines[1].strip()
    return ""

def isRemovable(path):

    if path.startswith('/dev/mapper') or path.startswith('/dev/dm-') or path.startswith('dm-'):
        return False

    if path.startswith("/dev/"):
        dev = re.match("/dev/(.*)", path).group(1)
    else:
        dev = path

    dev = dev.replace("/", "!")

    if dev.startswith("xvd"):
        is_cdrom = False
        f = None
        try:
            f = open(path, 'r')
            if fcntl.ioctl(f, CDROM_GET_CAPABILITY) == 0:
                is_cdrom = True
        except: # Any exception implies this is not a CDROM
            pass

        if f is not None:
            f.close()

        if is_cdrom:
            return True

    if os.path.exists("/sys/block/%s/removable" % dev):
        return int(__readOneLineFile__("/sys/block/%s/removable" % dev)) == 1
    else:
        return False

def isLargeBlockDisk(dev):
    """
    Determines whether a disk's logical block size is larger than 512 bytes
    (e.g. 4KB) with the consequence that "lvm" and "ext" SR types will not
    be able to make use of it.
    """
    return getDiskBlockSize(dev) > 512

def blockSizeToGBSize(blocks):
    return (int(blocks) * 512) // (1024 * 1024 * 1024)

def blockSizeToMBSize(blocks):
    return (int(blocks) * 512) // (1024 * 1024)

def blockSizeToBytes(blocks):
    return int(blocks) * 512

def bytesToHuman(num_bytes):
    kb = num_bytes // 1024
    mb = kb // 1024
    gb = mb // 1024

    if gb > 0:
        return "%d GB" % gb
    if mb > 0:
        return "%d MB" % mb
    if kb > 0:
        return "%d KB" % kb
    return "%d bytes" % num_bytes

def getHumanDiskSize(blocks):
    return bytesToHuman(blockSizeToBytes(blocks))

def getExtendedDiskInfo(disk, inMb=0):
    return (getDiskDeviceVendor(disk), getDiskDeviceModel(disk),
            inMb and (getDiskDeviceSize(disk)//2048) or getDiskDeviceSize(disk))


def readExtPartitionLabel(partition):
    """Read the ext partition label."""
    rc, out = util.runCmd2(['/sbin/e2label', partition], with_stdout=True)
    if rc == 0:
        label = out.strip()
    else:
        raise Exception("%s is not ext partition" % partition)
    return label

def getMdDeviceName(disk):
    rv, out = util.runCmd2(['mdadm', '--detail', '--export', disk],
                           with_stdout=True)
    for line in out.split("\n"):
        line = line.strip().split('=', 1)
        if line[0] == 'MD_DEVNAME':
            return line[1]

    return disk

def getHumanDiskName(disk):

    # For Multipath nodes return info about 1st slave
    if not disk.startswith("/dev/"):
        disk = '/dev/' + disk
    if isDeviceMapperNode(disk):
        return getHumanDiskName(getDeviceSlaves(disk)[0])
    if is_raid(disk):
        name = getMdDeviceName(disk)
        # mdadm may append an _ followed by a number (e.g. d0_0) to prevent
        # name collisions. Strip it if necessary.
        name = re.match("([^_]*)(_\d+)?$", name).group(1)
        return 'RAID: %s(%s)' % (name, ','.join(dev[5:] for dev in getDeviceSlaves(disk)))

    if disk.startswith('/dev/disk/by-id/'):
        return disk[16:]
    if disk.startswith('/dev/'):
        return disk[5:]
    return disk

def getHumanDiskLabel(disk, short=False):
    (vendor, model, size) = getExtendedDiskInfo(disk)
    template = "{device} - {size} [{vendor} {model}]" if not short else "{device} - {size}"
    return template.format(device=getHumanDiskName(disk), size=getHumanDiskSize(size),
                           vendor=vendor, model=model)

# given a list of disks, work out which ones are part of volume
# groups that will cause a problem if we install XE to those disks:
def findProblematicVGs(disks):
    real_disks = [os.path.realpath(d) for d in disks]

    # which disks are the volume groups on?
    vgdiskmap = {}
    tool = LVMTool()
    for pv in tool.pvs:
        if pv['vg_name'] not in vgdiskmap: vgdiskmap[pv['vg_name']] = []
        try:
            device = diskDevice(pv['pv_name'])
        except:
            # CA-35020: whole disk
            device = pv['pv_name']
        vgdiskmap[pv['vg_name']].append(device)

    # for each VG, map the disk list to a boolean list saying whether that
    # disk is in the set we're installing to:
    vgusedmap = {}
    for vg in vgdiskmap:
        vgusedmap[vg] = [disk in real_disks for disk in vgdiskmap[vg]]

    # now, a VG is problematic if it its vgusedmap entry contains a mixture
    # of True and False.  If it's entirely True or entirely False, that's OK:
    problems = []
    for vg in vgusedmap:
        p = False
        for x in vgusedmap[vg]:
            if x != vgusedmap[vg][0]:
                p = True
        if p:
            problems.append(vg)

    return problems

def log_available_disks():
    disks = getQualifiedDiskList()

    # make sure we have discovered at least one disk and
    # at least one network interface:
    if len(disks) == 0:
        logger.log("No disks found on this host.")
    else:
        # make sure that we have enough disk space:
        logger.log("Found disks: %s" % str(disks))
        diskSizes = [getDiskDeviceSize(x) for x in disks]
        diskSizesGB = [blockSizeToGBSize(x) for x in diskSizes]
        logger.log("Disk sizes: %s" % str(diskSizesGB))
        logger.log("Disk block sizes: %s" % [getDiskBlockSize(x)
                                             for x in disks])

        dom0disks = [x for x in diskSizesGB if constants.min_primary_disk_size <= x]
        if len(dom0disks) == 0:
            logger.log("Unable to find a suitable disk (with a size greater than %dGB) to install to." % constants.min_primary_disk_size)

class Disk:
    def __init__(self, device):
        self.device = device
        self.boot = (False, None)
        self.root = (None, None)
        self.state = (False, None)
        self.storage = (None, None)
        self.logs = (False, None)
        self.swap = (False, None)

INSTALL_RETAIL = 1
STORAGE_LVM = 1
STORAGE_OTHER = 2

def probeDisk(device):
    """Examines device and reports the apparent presence of a XenServer installation and/or related usage
    Returns a Disk object with XenServer partitions and state (boot, root, storage, logs, swap)

    Where:

        boot is a tuple of True or False and the partition device
        root is a tuple of None or INSTALL_RETAIL and the partition device
        state is a tuple of True or False and the partition device
        storage is a tuple of None, STORAGE_LVM or STORAGE_OTHER and the partition device
        logs is a tuple of True or False and the partition device
        swap is a tuple of True or False and the partition device
    """

    disk = Disk(device)
    possible_srs = []

    tool = PartitionTool(device)
    for num, part in tool.items():
        label = None
        part_device = tool._partitionDevice(num)

        if part['id'] == tool.ID_LINUX:
            try:
                label = readExtPartitionLabel(part_device)
            except:
                pass

        if part['id'] == tool.ID_LINUX:
            # probe for retail
            if label and label.startswith('root-'):
                disk.root = (INSTALL_RETAIL, part_device)
                disk.state = (True, part_device)
                if num + 2 in tool.partitions:
                    # George Retail and earlier didn't use the correct id for SRs
                    possible_srs = [num+2]
            elif label and label.startswith(constants.logsfs_label_prefix):
                disk.logs = (True, part_device)
        elif part['id'] == tool.ID_LINUX_LVM:
            if num not in possible_srs:
                possible_srs.append(num)
        elif part['id'] == tool.ID_LINUX_SWAP:
            disk.swap = (True, part_device)
        elif part['id'] == GPTPartitionTool.ID_EFI_BOOT or part['id'] == GPTPartitionTool.ID_BIOS_BOOT:
            disk.boot = (True, part_device)

    lv_tool = len(possible_srs) and LVMTool()
    for num in possible_srs:
        part_device = tool._partitionDevice(num)

        if lv_tool.isPartitionConfig(part_device):
            disk.state = (True, part_device)
        elif lv_tool.isPartitionSR(part_device):
            pv = lv_tool.deviceToPVOrNone(part_device)
            if pv is not None and pv['vg_name'].startswith(lv_tool.VG_OTHER_SR_PREFIX):
                disk.storage = (STORAGE_OTHER, part_device)
            else:
                disk.storage = (STORAGE_LVM, part_device)

    logger.log('Probe of %s found boot=%s root=%s disk.state=%s storage=%s logs=%s' %
                  (device, str(disk.boot), str(disk.root), str(disk.state), str(disk.storage), str(disk.logs)))

    return disk


# Keep track of iscsi disks we have logged into
iscsi_disks = []
# Keep track of NICs reserved for iSCSI boot
ibft_reserved_nics = set()


def get_initiator_name():
    """Return the iSCSI initiator name from the iBFT."""

    with open('%s/initiator/initiator-name' % constants.SYSFS_IBFT_DIR, 'r') as f:
        return f.read().strip()


def is_iscsi(device):
    """Return True if this is an iSCSI device."""

    # If this is a multipath device check whether the first slave is iSCSI
    if use_mpath:
        slaves = getDeviceSlaves(device)
        if slaves:
            device = slaves[0]

    major, minor = getMajMin(device)

    for d in iscsi_disks:
        try:
            if (major, minor) == getMajMin(d):
                return True
        except:
            pass

    return False


def configure_ibft_nic(target_ip, iface, ip, nm, gw):
    prefix = sum([bin(int(i)).count('1') for i in nm.split('.')])
    rv = util.runCmd2(['ip', 'addr', 'add', '%s/%s' % (ip, prefix), 'dev', iface])
    if rv:
        raise RuntimeError('Failed to initialize NIC for iSCSI')

    if netutil.network(ip, nm) == netutil.network(target_ip, nm):
        # Same subnet, don't use the gateway
        rv = util.runCmd2(['ip', 'route', 'add', target_ip, 'dev', iface])
    elif gw:
        rv = util.runCmd2(['ip', 'route', 'add', target_ip, 'dev', iface, 'via', gw])
    else:
        raise RuntimeError('A gateway is needed to initialize NIC for iSCSI')

    if rv:
        raise RuntimeError('Failed to initialize NIC for iSCSI')


# Set up the NICs according to the iBFT. It should be possible to use
# iscsistart -N to do this but that currently doesn't work with NICs which
# support offload (e.g. bnx2) even when offload is not being used.
def setup_ibft_nics():
    mac_map = {}
    netdevs = netutil.scanConfiguration()
    for name in netdevs:
        mac_map[netdevs[name].hwaddr] = name
    logger.log('NET: %s %s' % (repr(netdevs), repr(mac_map)))

    for t in glob.glob(os.path.join(constants.SYSFS_IBFT_DIR, 'target*')):
        with open(os.path.join(t, 'ip-addr'), 'r') as f:
            target_ip = f.read().strip()
        with open(os.path.join(t, 'nic-assoc'), 'r') as f:
            nic_assoc = f.read().strip()

        e = os.path.join(constants.SYSFS_IBFT_DIR, 'ethernet' + nic_assoc)
        with open(os.path.join(e, 'mac'), 'r') as f:
            mac = f.read().strip()
        with open(os.path.join(e, 'ip-addr'), 'r') as f:
            ip = f.read().strip()
        try:
            with open(os.path.join(e, 'gateway'), 'r') as f:
                gw = f.read().strip()
        except IOError as err:
            if err.errno == errno.ENOENT:
                gw = None
            else:
                raise
        with open(os.path.join(e, 'subnet-mask'), 'r') as f:
            nm = f.read().strip()
        with open(os.path.join(e, 'flags'), 'r') as f:
            flags = int(f.read().strip())
            if (flags & IBFT_BLOCK_VALID_FLAG) == 0:
                logger.log("Skipping %s not marked as valid" % (e,))
                continue

        if mac not in mac_map:
            raise RuntimeError('Found mac %s in iBFT but cannot find matching NIC' % mac)

        configure_ibft_nic(target_ip, mac_map[mac], ip, nm, gw)
        ibft_reserved_nics.add(mac_map[mac])


def dump_ibft():
    logger.log("Dump iBFT:")
    for path, dirs, files in os.walk('/sys/firmware/ibft'):
        for item in dirs:
            logger.log(os.path.join(path, item) + '/')
        for item in files:
            item =  os.path.join(path, item)
            with open(item, 'r') as f:
                data = f.read()
            logger.log('%s %s' % (item, repr(data)))
    logger.log("End of iBFT dump")


def write_iscsi_records(mounts, primary_disk):
    record = []
    node_name = node_address = node_port = None

    rv, out = util.runCmd2(['iscsistart', '-f'], with_stdout=True)
    if rv:
        raise Exception('Invalid iSCSI record')

    for line in out.split('\n'):
        line = line.strip()
        if not line:
            continue

        if line.startswith('node.name = '):
            node_name = line.split()[2]
        if line.startswith('node.conn[0].address = '):
            node_address = line.split()[2]
        if line.startswith('node.conn[0].port = '):
            node_port = line.split()[2]
        if line == '# END RECORD':
            if node_name is None or node_address is None or node_port is None:
                raise Exception('Invalid iSCSI record')

            # Ensure that the session does not get logged out during shutdown
            record.append('node.startup = onboot')
            # iscsistart hardcodes the target portal group tag to 1
            record.append('node.tpgt = 1')
            if isDeviceMapperNode(primary_disk):
                record.append('%s = %d\n' % ('node.session.timeo.replacement_timeout',
                                             constants.MPATH_ISCSI_TIMEOUT))
            record.append(line)

            path = os.path.join(mounts['root'], constants.ISCSI_NODES,
                                node_name, '%s,%s,1' % (node_address, node_port))
            os.makedirs(path)
            with open(os.path.join(path, 'default'), 'w') as f:
                f.write('\n'.join(record) + '\n')
            record = []
            node_name = node_address = node_port = None
            continue

        record.append(line)

    if record:
        raise Exception('Invalid iSCSI record')


def process_ibft(ui, interactive):
    """Process the iBFT.

    Bring up any disks that the iBFT says should be attached, and reserve the
    NICs that it says should be used for iSCSI.
    """

    util.runCmd2([ '/sbin/iscsiadm', '-k', '0'])
    rv = util.runCmd2(['iscsid'])
    if rv:
        raise RuntimeError('Failed to start iscsid')

    nics = set()
    targets = 0
    rv, out = util.runCmd2(['iscsistart', '-f'], with_stdout=True)
    if rv:
        logger.log("process_ibft: No valid iBFT found.")

        # Dump iBFT state for debugging
        dump_ibft()

        return
    for line in out.split('\n'):
        m = re.match('iface.net_ifacename = (.*)$', line.strip())
        if m:
            nics.add(m.group(1))
        m = re.match(r'node.conn\[\d+\].address = ', line.strip())
        if m:
            targets += 1

    # Do nothing if the iBFT contains no valid targets
    if targets == 0:
        logger.log("process_ibft: No valid target configs found in iBFT")
        return

    # If interactive, ask user if he wants to proceed
    if ui and interactive:
        msg = \
            "Found iSCSI Boot Firmware Table\n\nAttach to disks specified in iBFT?\n\n" \
            "This will reserve %s for iSCSI disk access.  Reserved NICs are not available " \
            "for use as the management interface or for use by virtual machines."  % " and ".join(sorted(nics))
        button = ButtonChoiceWindowEx(ui.screen, "Attach iSCSI disks" , msg, ['Yes', 'No'], width=60)
        if button == 'no':
            return

    setup_ibft_nics()

    # Attach disks
    rv = util.runCmd2(['iscsistart', '-b'])
    if rv:
        raise RuntimeError('Failed to attach iSCSI target disk(s)')

    util.runCmd2(util.udevsettleCmd())
    time.sleep(5)

    rv, out = util.runCmd2([ 'iscsiadm', '-m', 'session', '-P', '3' ],
                           with_stdout=True)
    if rv:
        raise RuntimeError('Failed to find attached disks')
    for line in out.split('\n'):
        m = re.match(r'\s*Attached scsi disk (\w+)\s+.*$', line)
        if m:
            iscsi_disks.append('/dev/' + m.group(1))

    logger.log('process_ibft: iSCSI Disks: %s' % (str(iscsi_disks),))
    logger.log('process_ibft: Reserved NICs: %s' % (str(list(ibft_reserved_nics)),))


def release_ibft_disks():
    if util.pidof('iscsid'):
        util.runCmd2([ '/sbin/iscsiadm', '-m', 'session', '-u'])
        util.runCmd2([ '/sbin/iscsiadm', '-k', '0'])
        iscsi_disks = []


def is_raid(disk):
    return disk in getMdNodes()


def dev_from_devpath(devpath):
    """Returns the dev number of the device as a tuple."""

    devno = os.stat(devpath).st_rdev
    return os.major(devno), os.minor(devno)


def dev_from_sysfs(path):
    """Returns the dev number as a tuple from a sysfs entry."""

    with open('%s/dev' % path, 'r') as f:
        return tuple(map(int, f.read().strip().split(':')))


# The logic for this function is based on sysfs_devno_to_wholedisk in
# util-linux. See that function for reasoning.
def parentdev_from_devpath(devpath):
    """Returns the dev number of the parent device, or None if there isn't
    one."""

    try:
        devno = os.stat(devpath).st_rdev
        major = os.major(devno)
        minor = os.minor(devno)
        syspath = '/sys/dev/block/%d:%d' % (major, minor)

        partitionpath = syspath + '/partition'
        if os.path.exists(partitionpath):
            linkpath = os.path.realpath(syspath)
            parent = os.path.dirname(linkpath)
            return dev_from_sysfs(parent)
        else:
            dm_uuidpath = syspath + '/dm/uuid'
            if os.path.exists(dm_uuidpath):
                with open(dm_uuidpath, 'r') as f:
                    dm_uuid = f.read().strip()
                if re.match('part[0-9+]-', dm_uuid):
                    parent = os.listdir(syspath + '/slaves')[0]
                    return dev_from_sysfs('%s/slaves/%s' % (syspath, parent))
    except Exception as e:
        logger.logException(e)

    # If there is no parent of the parent cannot be determined...
    return None

def fs_type_from_device(device):
    (rc, stdout) = util.runCmd2(['/bin/lsblk', '-n', '-o', 'FSTYPE', device], with_stdout=True)
    if rc == 0:
        return stdout.strip()

    msg = "Failed to identify filesystem type on %s" % device
    logger.log(msg)
    raise Exception(msg)