/usr/lib/python2.7/dist-packages/rtslib/utils.py is in python-rtslib-fb 2.1.45-4.
This file is owned by root:root, with mode 0o644.
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Provides various utility functions.
This file is part of RTSLib.
Copyright (c) 2011-2013 by Datera, Inc
Licensed under the Apache License, Version 2.0 (the "License"); you may
not use this file except in compliance with the License. You may obtain
a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
License for the specific language governing permissions and limitations
under the License.
'''
import re
import os
import stat
import uuid
import socket
import subprocess
from contextlib import contextmanager
class RTSLibError(Exception):
'''
Generic rtslib error.
'''
pass
class RTSLibBrokenLink(RTSLibError):
'''
Broken link in configfs, i.e. missing LUN storage object.
'''
pass
class RTSLibNotInCFS(RTSLibError):
'''
The underlying configfs object does not exist. Happens when
calling methods of an object that is instantiated but have
been deleted from congifs, or when trying to lookup an
object that does not exist.
'''
pass
def fwrite(path, string):
'''
This function writes a string to a file, and takes care of
opening it and closing it. If the file does not exist, it
will be created.
>>> from rtslib.utils import *
>>> fwrite("/tmp/test", "hello")
>>> fread("/tmp/test")
'hello'
@param path: The file to write to.
@type path: string
@param string: The string to write to the file.
@type string: string
'''
with open(path, 'w') as file_fd:
file_fd.write(str(string))
def fread(path):
'''
This function reads the contents of a file.
It takes care of opening and closing it.
>>> from rtslib.utils import *
>>> fwrite("/tmp/test", "hello")
>>> fread("/tmp/test")
'hello'
>>> fread("/tmp/notexistingfile") # doctest: +ELLIPSIS
Traceback (most recent call last):
...
IOError: [Errno 2] No such file or directory: '/tmp/notexistingfile'
@param path: The path to the file to read from.
@type path: string
@return: A string containing the file's contents.
'''
with open(path, 'r') as file_fd:
return file_fd.read().strip()
def is_dev_in_use(path):
'''
This function will check if the device or file referenced by path is
already mounted or used as a storage object backend. It works by trying to
open the path with O_EXCL flag, which will fail if someone else already
did. Note that the file is closed before the function returns, so this
does not guaranteed the device will still be available after the check.
@param path: path to the file of device to check
@type path: string
@return: A boolean, True is we cannot get exclusive descriptor on the path,
False if we can.
'''
path = os.path.realpath(str(path))
try:
file_fd = os.open(path, os.O_EXCL|os.O_NDELAY)
except OSError:
return True
else:
os.close(file_fd)
return False
def get_blockdev_size(path):
'''
Returns the size in logical blocks of a disk-type block device.
'''
name = os.path.basename(os.path.realpath(path))
# size is in 512-byte sectors, we want to return number of logical blocks
def get_size(path, is_partition=False):
sect_size = int(fread("%s/size" % path))
if is_partition:
path = os.path.split(path)[0]
logical_block_size = int(fread("%s/queue/logical_block_size" % path))
return sect_size / (logical_block_size / 512)
try:
return get_size("/sys/block/%s" % name)
except IOError:
# Maybe it's a partition?
m = re.search(r'^([a-z0-9_-]+)(\d+)$', name)
if m:
# If disk name ends with a digit, Linux sticks a 'p' between it and
# the partition number in the blockdev name.
disk = m.groups()[0]
if disk[-1] == 'p' and disk[-2].isdigit():
disk = disk[:-1]
return get_size("/sys/block/%s/%s" % (disk, m.group()), True)
else:
raise
get_block_size = get_blockdev_size
def get_blockdev_type(path):
'''
This function returns a block device's type.
Example: 0 is TYPE_DISK
If no match is found, None is returned.
>>> from rtslib.utils import *
>>> get_blockdev_type("/dev/sda")
0
>>> get_blockdev_type("/dev/sr0")
5
>>> get_blockdev_type("/dev/scd0")
5
>>> get_blockdev_type("/dev/nodevicehere") is None
True
@param path: path to the block device
@type path: string
@return: An int for the block device type, or None if not a block device.
'''
dev = os.path.realpath(path)
# is dev a block device?
try:
mode = os.stat(dev)
except OSError:
return None
if not stat.S_ISBLK(mode[stat.ST_MODE]):
return None
# assume disk if device/type is missing
disk_type = 0
with ignored(IOError):
disk_type = int(fread("/sys/block/%s/device/type" % os.path.basename(dev)))
return disk_type
get_block_type = get_blockdev_type
def convert_scsi_path_to_hctl(path):
'''
This function returns the SCSI ID in H:C:T:L form for the block
device being mapped to the udev path specified.
If no match is found, None is returned.
>>> import rtslib.utils as utils
>>> utils.convert_scsi_path_to_hctl('/dev/scd0')
(2, 0, 0, 0)
>>> utils.convert_scsi_path_to_hctl('/dev/sr0')
(2, 0, 0, 0)
>>> utils.convert_scsi_path_to_hctl('/dev/sda')
(3, 0, 0, 0)
>>> utils.convert_scsi_path_to_hctl('/dev/sda1')
>>> utils.convert_scsi_path_to_hctl('/dev/sdb')
(3, 0, 1, 0)
>>> utils.convert_scsi_path_to_hctl('/dev/sdc')
(3, 0, 2, 0)
@param path: The udev path to the SCSI block device.
@type path: string
@return: An (host, controller, target, lun) tuple of integer
values representing the SCSI ID of the device, or None if no
match is found.
'''
devname = os.path.basename(os.path.realpath(path))
try:
hctl = os.listdir("/sys/block/%s/device/scsi_device"
% devname)[0].split(':')
except:
return None
return [int(data) for data in hctl]
def convert_scsi_hctl_to_path(host, controller, target, lun):
'''
This function returns a udev path pointing to the block device being
mapped to the SCSI device that has the provided H:C:T:L.
>>> import rtslib.utils as utils
>>> utils.convert_scsi_hctl_to_path(0,0,0,0)
''
>>> utils.convert_scsi_hctl_to_path(2,0,0,0) # doctest: +ELLIPSIS
'/dev/s...0'
>>> utils.convert_scsi_hctl_to_path(3,0,2,0)
'/dev/sdc'
@param host: The SCSI host id.
@type host: int
@param controller: The SCSI controller id.
@type controller: int
@param target: The SCSI target id.
@type target: int
@param lun: The SCSI Logical Unit Number.
@type lun: int
@return: A string for the canonical path to the device, or empty string.
'''
try:
host = int(host)
controller = int(controller)
target = int(target)
lun = int(lun)
except ValueError:
raise RTSLibError(
"The host, controller, target and lun parameter must be integers.")
for devname in os.listdir("/sys/block"):
path = "/dev/%s" % devname
hctl = [host, controller, target, lun]
if convert_scsi_path_to_hctl(path) == hctl:
return os.path.realpath(path)
return ''
def generate_wwn(wwn_type):
'''
Generates a random WWN of the specified type:
- unit_serial: T10 WWN Unit Serial.
- iqn: iSCSI IQN
- naa: SAS NAA address
@param wwn_type: The WWN address type.
@type wwn_type: str
@returns: A string containing the WWN.
'''
wwn_type = wwn_type.lower()
if wwn_type == 'free':
return str(uuid.uuid4())
if wwn_type == 'unit_serial':
return str(uuid.uuid4())
elif wwn_type == 'iqn':
localname = socket.gethostname().split(".")[0]
localarch = os.uname()[4].replace("_", "")
prefix = "iqn.2003-01.org.linux-iscsi.%s.%s" % (localname, localarch)
prefix = prefix.strip().lower()
serial = "sn.%s" % str(uuid.uuid4())[24:]
return "%s:%s" % (prefix, serial)
elif wwn_type == 'naa':
# see http://standards.ieee.org/develop/regauth/tut/fibre.pdf
# 5 = IEEE registered
# 001405 = OpenIB OUI (they let us use it I guess?)
# rest = random
return "naa.5001405" + uuid.uuid4().get_hex()[-9:]
elif wwn_type == 'eui':
return "eui.001405" + uuid.uuid4().get_hex()[-10:]
else:
raise ValueError("Unknown WWN type: %s." % wwn_type)
def colonize(str):
'''
helper function to add colons every 2 chars
'''
return ":".join(str[i:i+2] for i in range(0, len(str), 2))
def _cleanse_wwn(wwn_type, wwn):
'''
Some wwns may have alternate text representations. Adjust to our
preferred representation.
'''
wwn = str(wwn.strip()).lower()
if wwn_type in ('naa', 'eui', 'ib'):
if wwn.startswith("0x"):
wwn = wwn[2:]
wwn = wwn.replace("-", "")
wwn = wwn.replace(":", "")
if not (wwn.startswith("naa.") or wwn.startswith("eui.") or \
wwn.startswith("ib.")):
wwn = wwn_type + "." + wwn
return wwn
def normalize_wwn(wwn_types, wwn):
'''
Take a WWN as given by the user and convert it to a standard text
representation. If possible_wwns is not None, verify that
the given WWN is on that list.
Returns (normalized_wwn, wwn_type), or exception if invalid wwn.
'''
wwn_test = {
'free': lambda wwn: True,
'iqn': lambda wwn: \
re.match("iqn\.[0-9]{4}-[0-1][0-9]\..*\..*", wwn) \
and not re.search(' ', wwn) \
and not re.search('_', wwn),
'naa': lambda wwn: re.match("naa\.[125][0-9a-fA-F]{15}$", wwn),
'eui': lambda wwn: re.match("eui\.[0-9a-f]{16}$", wwn),
'ib': lambda wwn: re.match("ib\.[0-9a-f]{32}$", wwn),
'unit_serial': lambda wwn: \
re.match("[0-9A-Fa-f]{8}(-[0-9A-Fa-f]{4}){3}-[0-9A-Fa-f]{12}$", wwn),
}
for wwn_type in wwn_types:
clean_wwn = _cleanse_wwn(wwn_type, wwn)
found_type = wwn_test[wwn_type](clean_wwn)
if found_type:
break
else:
raise RTSLibError("WWN not valid as: %s" % ", ".join(wwn_types))
return (clean_wwn, wwn_type)
def list_loaded_kernel_modules():
'''
List all currently loaded kernel modules
'''
return [line.split(" ")[0] for line in
fread("/proc/modules").split('\n') if line]
def modprobe(module):
'''
Load the specified kernel module if needed.
@param module: The name of the kernel module to be loaded.
@type module: str
'''
if module in list_loaded_kernel_modules():
return
try:
import kmod
kmod.Kmod().modprobe(module)
except ImportError:
process = subprocess.Popen(("modprobe", module),
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
(stdoutdata, stderrdata) = process.communicate()
if process.returncode != 0:
raise RTSLibError(stderrdata)
def mount_configfs():
if not os.path.ismount("/sys/kernel/config"):
cmdline = "mount -t configfs none /sys/kernel/config"
process = subprocess.Popen(cmdline.split(),
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
(stdoutdata, stderrdata) = process.communicate()
if process.returncode != 0:
raise RTSLibError("Cannot mount configfs.")
def dict_remove(d, items):
for item in items:
if item in d:
del d[item]
@contextmanager
def ignored(*exceptions):
try:
yield
except exceptions:
pass
#
# These two functions are meant to be used with functools.partial and
# properties.
#
# 'ignore=True' will silently return None if the attribute is not present.
# This is good for attributes only present in some kernel versions.
#
# All curried arguments should be keyword args.
#
# These should only be used for attributes that follow the convention of
# "NULL" having a special sentinel value, such as auth attributes, and
# that return a string.
#
def _get_auth_attr(self, attribute, ignore=False):
self._check_self()
path = "%s/%s" % (self.path, attribute)
try:
value = fread(path)
except:
if not ignore:
raise
return None
if value == "NULL":
return ''
else:
return value
# Auth params take the string "NULL" to unset the attribute
def _set_auth_attr(self, value, attribute, ignore=False):
self._check_self()
path = "%s/%s" % (self.path, attribute)
value = value.strip()
if value == "NULL":
raise ValueError("'NULL' is not a permitted value")
if value == '':
value = "NULL"
try:
fwrite(path, "%s" % value)
except:
if not ignore:
raise
def set_attributes(obj, attr_dict):
for name, value in attr_dict.iteritems():
# Setting some attributes may return an error, before kernel 3.3
with ignored(RTSLibError):
obj.set_attribute(name, value)
def set_parameters(obj, param_dict):
for name, value in param_dict.iteritems():
# Setting some parameters may return an error, before kernel 3.3
with ignored(RTSLibError):
obj.set_parameter(name, value)
def _test():
'''Run the doctests'''
import doctest
doctest.testmod()
if __name__ == "__main__":
_test()
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