path: root/storage/udev.py

# udev.py
# Python module for querying the udev database for device information.
#
# Copyright (C) 2009  Red Hat, Inc.
#
# This copyrighted material is made available to anyone wishing to use,
# modify, copy, or redistribute it subject to the terms and conditions of
# the GNU General Public License v.2, or (at your option) any later version.
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY expressed or implied, including the implied warranties 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.  Any Red Hat trademarks that are incorporated in the
# source code or documentation are not subject to the GNU General Public
# License and may only be used or replicated with the express permission of
# Red Hat, Inc.
#
# Red Hat Author(s): Dave Lehman <dlehman@redhat.com>
#

import os
import stat

import iutil
from errors import *
from baseudev import *

import logging
log = logging.getLogger("storage")

def udev_resolve_devspec(devspec):
    if not devspec:
        return None

    import devices as _devices
    ret = None
    for dev in udev_get_block_devices():
        if devspec.startswith("LABEL="):
            if udev_device_get_label(dev) == devspec[6:]:
                ret = dev
                break
        elif devspec.startswith("UUID="):
            if udev_device_get_uuid(dev) == devspec[5:]:
                ret = dev
                break
        else:
            if udev_device_get_name(dev) == _devices.devicePathToName(devspec):
                ret = dev
                break

    del _devices
    if ret:
        return udev_device_get_name(dev)

def udev_get_block_devices():
    udev_settle(timeout=30)
    entries = []
    for path in udev_enumerate_block_devices():
        entry = udev_get_block_device(path)
        if entry:
            entries.append(entry)
    return entries

def __is_blacklisted_blockdev(dev_name):
    """Is this a blockdev we never want for an install?"""
    if dev_name.startswith("loop") or dev_name.startswith("ram") or dev_name.startswith("fd"):
        return True
    # FIXME: the backing dev for the live image can't be used as an
    # install target.  note that this is a little bit of a hack 
    # since we're assuming that /dev/live will exist
    if os.path.exists("/dev/live") and \
            stat.S_ISBLK(os.stat("/dev/live")[stat.ST_MODE]):
        livetarget = os.path.realpath("/dev/live")
        if livetarget.startswith("/dev"):
            livetarget = livetarget[5:]
        if livetarget.startswith(dev_name):
            log.info("%s looks to be the live device; ignoring" % (dev_name,))
            return True

    if os.path.exists("/sys/class/block/%s/device/model" %(dev_name,)):
        model = open("/sys/class/block/%s/device/model" %(dev_name,)).read()
        for bad in ("IBM *STMF KERNEL", "SCEI Flash-5", "DGC LUNZ"):
            if model.find(bad) != -1:
                log.info("ignoring %s with model %s" %(dev_name, model))
                return True

    return False

def udev_enumerate_block_devices():
    import os.path

    return filter(lambda d: not __is_blacklisted_blockdev(os.path.basename(d)),
                  udev_enumerate_devices(deviceClass="block"))

def udev_get_block_device(sysfs_path):
    dev = udev_get_device(sysfs_path)
    if not dev or not dev.has_key("name"):
        return {"name": None, "symlinks": []}
    else:
        return dev

def udev_parse_block_entry(buf):
    dev = udev_parse_entry(buf)

    for (key, value) in dev.iteritems():
        if value.count(" "):
            # eg: DEVLINKS
            dev.update({key: value.split()})

    return dev


# These are functions for retrieving specific pieces of information from
# udev database entries.
def udev_device_get_name(udev_info):
    """ Return the best name for a device based on the udev db data. """
    return udev_info.get("DM_NAME", udev_info["name"])

def udev_device_get_format(udev_info):
    """ Return a device's format type as reported by udev. """
    return udev_info.get("ID_FS_TYPE")

def udev_device_get_uuid(udev_info):
    """ Get the UUID from the device's format as reported by udev. """
    md_uuid = udev_info.get("MD_UUID")
    uuid = udev_info.get("ID_FS_UUID")
    # we don't want to return the array's uuid as a member's uuid
    if uuid and not md_uuid == uuid:
        return udev_info.get("ID_FS_UUID")

def udev_device_get_label(udev_info):
    """ Get the label from the device's format as reported by udev. """
    return udev_info.get("ID_FS_LABEL")

def udev_device_is_dm(info):
    """ Return True if the device is a device-mapper device. """
    return info.has_key("DM_NAME")

def udev_device_is_md(info):
    """ Return True if the device is a mdraid array device. """
    return info.has_key("MD_DEVNAME") and \
           info.has_key("MD_METADATA")

def udev_device_is_cdrom(info):
    """ Return True if the device is an optical drive. """
    # FIXME: how can we differentiate USB drives from CD-ROM drives?
    #         -- USB drives also generate a sdX device.
    return info.get("ID_CDROM") == "1"

def udev_device_is_disk(info):
    """ Return True is the device is a disk. """
    has_range = os.path.exists("/sys/%s/range" % info['sysfs_path'])
    return info.get("DEVTYPE") == "disk" or has_range

def udev_device_is_partition(info):
    has_start = os.path.exists("/sys/%s/start" % info['sysfs_path'])
    return info.get("DEVTYPE") == "partition" or has_start

def udev_device_get_sysfs_path(info):
    return info['sysfs_path']

def udev_device_get_major(info):
    return int(info["MAJOR"])

def udev_device_get_minor(info):
    return int(info["MINOR"])

def udev_device_get_md_level(info):
    return info["MD_LEVEL"]

def udev_device_get_md_devices(info):
    return int(info["MD_DEVICES"])

def udev_device_get_md_uuid(info):
    return info["MD_UUID"]

def udev_device_get_vg_name(info):
    return info['LVM2_VG_NAME']

def udev_device_get_vg_uuid(info):
    return info['LVM2_VG_UUID']

def udev_device_get_vg_size(info):
    # lvm's decmial precision is not configurable, so we tell it to use
    # KB and convert to MB here
    return float(info['LVM2_VG_SIZE']) / 1024

def udev_device_get_vg_free(info):
    # lvm's decmial precision is not configurable, so we tell it to use
    # KB and convert to MB here
    return float(info['LVM2_VG_FREE']) / 1024

def udev_device_get_vg_extent_size(info):
    # lvm's decmial precision is not configurable, so we tell it to use
    # KB and convert to MB here
    return float(info['LVM2_VG_EXTENT_SIZE']) / 1024

def udev_device_get_vg_extent_count(info):
    return int(info['LVM2_VG_EXTENT_COUNT'])

def udev_device_get_vg_free_extents(info):
    return int(info['LVM2_VG_FREE_COUNT'])

def udev_device_get_vg_pv_count(info):
    return int(info['LVM2_PV_COUNT'])

def udev_device_get_pv_pe_start(info):
    # lvm's decmial precision is not configurable, so we tell it to use
    # KB and convert to MB here
    return float(info['LVM2_PE_START']) / 1024

def udev_device_get_lv_names(info):
    names = info['LVM2_LV_NAME']
    if not names:
        names = []
    elif not isinstance(names, list):
        names = [names]
    return names

def udev_device_get_lv_uuids(info):
    uuids = info['LVM2_LV_UUID']
    if not uuids:
        uuids = []
    elif not isinstance(uuids, list):
        uuids = [uuids]
    return uuids

def udev_device_get_lv_sizes(info):
    # lvm's decmial precision is not configurable, so we tell it to use
    # KB and convert to MB here
    sizes = info['LVM2_LV_SIZE']
    if not sizes:
        sizes = []
    elif not isinstance(sizes, list):
        sizes = [sizes]

    return [float(s) / 1024 for s in sizes]

def udev_device_is_biosraid(info):
    # Note that this function does *not* identify raid sets.
    # Tests to see if device is parto of a dmraid set.
    # dmraid and mdraid have the same ID_FS_USAGE string, ID_FS_TYPE has a
    # string that describes the type of dmraid (isw_raid_member...),  I don't
    # want to maintain a list and mdraid's ID_FS_TYPE='linux_raid_member', so
    # dmraid will be everything that is raid and not linux_raid_member
    from formats.dmraid import DMRaidMember
    from formats.mdraid import MDRaidMember
    if info.has_key("ID_FS_TYPE") and \
            (info["ID_FS_TYPE"] in DMRaidMember._udevTypes or \
             info["ID_FS_TYPE"] in MDRaidMember._udevTypes) and \
            info["ID_FS_TYPE"] != "linux_raid_member":
        return True

    return False

def udev_device_get_dmraid_partition_disk(info):
    try:
        p_index = info["DM_NAME"].rindex("p")
    except (KeyError, AttributeError, ValueError):
        return None

    if not info["DM_NAME"][p_index+1:].isdigit():
        return None

    return info["DM_NAME"][:p_index]

def udev_device_is_dmraid_partition(info, devicetree):
    diskname = udev_device_get_dmraid_partition_disk(info)
    dmraid_devices = devicetree.getDevicesByType("dm-raid array")

    for device in dmraid_devices:
        if diskname == device.name:
            return True

    return False

# iscsi disks have ID_PATH in the form of:
# ip-${iscsi_address}:${iscsi_port}-iscsi-${iscsi_tgtname}-lun-${lun}
def udev_device_is_iscsi(info):
    try:
        path_components = info["ID_PATH"].split("-")

        if info["ID_BUS"] == "scsi" and len(path_components) >= 6 and \
           path_components[0] == "ip" and path_components[2] == "iscsi":
            return True
    except KeyError:
        pass

    return False

def udev_device_get_iscsi_name(info):
    path_components = info["ID_PATH"].split("-")

    # Tricky, the name itself contains atleast 1 - char
    return "-".join(path_components[3:len(path_components)-2])

def udev_device_get_iscsi_address(info):
    path_components = info["ID_PATH"].split("-")

    return path_components[1].split(":")[0]

def udev_device_get_iscsi_port(info):
    path_components = info["ID_PATH"].split("-")

    return path_components[1].split(":")[1]

# fcoe disks have ID_PATH in the form of:
# pci-eth#-fc-${id}
# fcoe parts look like this:
# pci-eth#-fc-${id}-part#
def udev_device_is_fcoe(info):
    try:
        path_components = info["ID_PATH"].split("-")

        if info["ID_BUS"] == "scsi" and len(path_components) >= 4 and \
           path_components[0] == "pci" and path_components[2] == "fc" and \
           path_components[1][0:3] == "eth":
            return True
    except LookupError:
        pass

    return False

def udev_device_get_fcoe_nic(info):
    path_components = info["ID_PATH"].split("-")

    return path_components[1]

def udev_device_get_fcoe_identifier(info):
    path_components = info["ID_PATH"].split("-")

    return path_components[3]