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 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
        elif udev_device_get_name(dev) == _devices.devicePathToName(devspec):
            ret = dev
            break
        else:
            for link in dev["symlinks"]:
                if devspec == "/dev/" + link:
                    ret = dev
                    break

    del _devices
    if ret:
        return udev_device_get_name(ret)

def udev_resolve_glob(glob):
    import fnmatch
    ret = []

    if not glob:
        return ret

    for dev in udev_get_block_devices():
        name = udev_device_get_name(dev)

        if fnmatch.fnmatch(name, glob):
            ret.append(name)
        else:
            for link in dev["symlinks"]:
                if fnmatch.fnmatch("/dev/" + link, glob):
                    ret.append(name)

    return ret

def udev_get_block_devices():
    udev_settle()
    entries = []
    for path in udev_enumerate_block_devices():
        entry = udev_get_block_device(path)
        if entry:
            if entry["name"].startswith("md"):
                # mdraid is really braindead, when a device is stopped
                # it is no longer usefull in anyway (and we should not
                # probe it) yet it still sticks around, see bug rh523387
                state = None
                state_file = "/sys/%s/md/array_state" % entry["sysfs_path"]
                if os.access(state_file, os.R_OK):
                    state = open(state_file).read().strip()
                if state == "clear":
                    continue
            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

    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 None
    else:
        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. """
    # isw raid set *members* have MD_METADATA set, but are not arrays!
    return info.has_key("MD_METADATA") and \
           info.get("ID_FS_TYPE") != "isw_raid_member"

def udev_device_is_cciss(info):
    """ Return True if the device is a CCISS device. """
    return udev_device_get_name(info).startswith("cciss")

def udev_device_is_dasd(info):
    """ Return True if the device is a dasd device. """
    devname = info.get("DEVNAME")
    if devname:
        return devname.startswith("dasd")
    else:
        return False

def udev_device_is_zfcp(info):
    """ Return True if the device is a zfcp device. """
    if info.get("DEVTYPE") != "disk":
        return False

    subsystem = "/sys" + info.get("sysfs_path")

    while True:
        topdir = os.path.realpath(os.path.dirname(subsystem))
        driver = "%s/driver" % (topdir,)

        if os.path.islink(driver):
            subsystemname = os.path.basename(os.readlink(subsystem))
            drivername = os.path.basename(os.readlink(driver))

            if subsystemname == 'ccw' and drivername == 'zfcp':
                return True

        newsubsystem = os.path.dirname(topdir)

        if newsubsystem == topdir:
            break

        subsystem = newsubsystem + "/subsystem"

    return False

def udev_device_get_zfcp_attribute(info, attr=None):
    """ Return the value of the specified attribute of the zfcp device. """
    if not attr:
        log.debug("udev_device_get_zfcp_attribute() called with attr=None")
        return None

    attribute = "/sys%s/device/%s" % (info.get("sysfs_path"), attr,)
    attribute = os.path.realpath(attribute)

    if not os.path.isfile(attribute):
        log.warning("%s is not a valid zfcp attribute" % (attribute,))
        return None

    return open(attribute, "r").read().strip()

def udev_device_get_dasd_bus_id(info):
    """ Return the CCW bus ID of the dasd device. """
    return info.get("sysfs_path").split("/")[-3]

def udev_device_get_dasd_flag(info, flag=None):
    """ Return the specified flag for the dasd device. """
    if flag is None:
        return None

    path = "/sys" + info.get("sysfs_path") + "/device/" + flag
    if not os.path.isfile(path):
        return None

    return open(path, 'r').read().strip()

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. """
    if udev_device_is_cdrom(info):
        return False
    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_serial(udev_info):
    """ Get the serial number/UUID from the device as reported by udev. """
    return udev_info.get("ID_SERIAL_SHORT", udev_info.get("ID_SERIAL"))

def udev_device_get_wwid(udev_info):
    """ The WWID of a device is typically just its serial number, but with
        colons in the name to make it more readable. """
    serial = udev_device_get_serial(udev_info)

    if serial and len(serial) == 32:
        retval = ""
        for i in range(0, 16):
            retval += serial[i*2:i*2+2] + ":"

        return retval[0:-1]

    return ""

def udev_device_get_vendor(udev_info):
    """ Get the vendor of the device as reported by udev. """
    return udev_info.get("ID_VENDOR_FROM_DATABASE", udev_info.get("ID_VENDOR"))

def udev_device_get_model(udev_info):
    """ Get the model of the device as reported by udev. """
    return udev_info.get("ID_MODEL_FROM_DATABASE", udev_info.get("ID_MODEL"))

def udev_device_get_bus(udev_info):
    """ Get the bus a device is connected to the system by. """
    return udev_info.get("ID_BUS", "").upper()

def udev_device_get_path(info):
    return info["ID_PATH"]

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.get("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_md_container(info):
    return info.get("MD_CONTAINER")

def udev_device_get_md_name(info):
    return info.get("MD_DEVNAME")

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_get_lv_attr(info):
    attr = info['LVM2_LV_ATTR']
    if not attr:
        attr = []
    elif not isinstance(attr, list):
        attr = [attr]
    return attr

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

def udev_device_is_multipath_partition(info, devicetree):
    """ Return True if the device is a partition of a multipath device. """
    if not udev_device_is_dm(info):
        return False
    if not info["DM_NAME"].startswith("mpath"):
        return False
    diskname = udev_device_get_dmraid_partition_disk(info)
    if diskname is None:
        return False

    # this is sort of a lame check, but basically, if diskname gave us "mpath0"
    # and we start with "mpath" but we're not "mpath0", then we must be
    # "mpath0" plus some non-numeric crap.
    if diskname != info["DM_NAME"]:
        return True

    return False

def udev_device_get_multipath_partition_disk(info):
    """ Return True if the device is a partition of a multipath device. """
    # XXX PJFIX This whole function is crap.
    if not udev_device_is_dm(info):
        return False
    if not info["DM_NAME"].startswith("mpath"):
        return False
    diskname = udev_device_get_dmraid_partition_disk(info)
    return diskname

def udev_device_is_multipath_member(info):
    """ Return True if the device is part of a multipath. """
    return info.get("ID_FS_TYPE") == "multipath_member"

def udev_device_get_multipath_name(info):
    """ Return the name of the multipath that the device is a member of. """
    if udev_device_is_multipath_member(info):
        return info['ID_MPATH_NAME']
    return None

# 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 = udev_device_get_path(info).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 = udev_device_get_path(info).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 = udev_device_get_path(info).split("-")

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

def udev_device_get_iscsi_port(info):
    path_components = udev_device_get_path(info).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 = udev_device_get_path(info).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 = udev_device_get_path(info).split("-")

    return path_components[1]

def udev_device_get_fcoe_identifier(info):
    path_components = udev_device_get_path(info).split("-")

    return path_components[3]