'''
Implements access to the NVMe target configfs hierarchy
Copyright (c) 2011-2013 by Datera, Inc.
Copyright (c) 2011-2014 by Red Hat, Inc.
Copyright (c) 2016 by HGST, a Western Digital Company.
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 os
import stat
import uuid
import json
from glob import iglob as glob
DEFAULT_SAVE_FILE = '/etc/nvmet/config.json'
class CFSError(Exception):
'''
Generic slib error.
'''
pass
class CFSNotFound(CFSError):
'''
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
class CFSNode(object):
configfs_dir = '/sys/kernel/config/nvmet'
def __init__(self):
self._path = self.configfs_dir
self._enable = None
self.attr_groups = []
def __eq__(self, other):
return self._path == other._path
def __ne__(self, other):
return self._path != other._path
def _get_path(self):
return self._path
def _create_in_cfs(self, mode):
'''
Creates the configFS node if it does not already exist, depending on
the mode.
any -> makes sure it exists, also works if the node already does exist
lookup -> make sure it does NOT exist
create -> create the node which must not exist beforehand
'''
if mode not in ['any', 'lookup', 'create']:
raise CFSError("Invalid mode: %s" % mode)
if self.exists and mode == 'create':
raise CFSError("This %s already exists in configFS" %
self.__class__.__name__)
elif not self.exists and mode == 'lookup':
raise CFSNotFound("No such %s in configfs: %s" %
(self.__class__.__name__, self.path))
if not self.exists:
try:
os.mkdir(self.path)
except:
raise CFSError("Could not create %s in configFS" %
self.__class__.__name__)
self.get_enable()
def _exists(self):
return os.path.isdir(self.path)
def _check_self(self):
if not self.exists:
raise CFSNotFound("This %s does not exist in configFS" %
self.__class__.__name__)
def list_attrs(self, group, writable=None):
'''
@param group: The attribute group
@param writable: If None (default), returns all attributes, if True,
returns read-write attributes, if False, returns just the read-only
attributes.
@type writable: bool or None
@return: A list of existing attribute names as strings.
'''
self._check_self()
names = [os.path.basename(name).split('_', 1)[1]
for name in glob("%s/%s_*" % (self._path, group))
if os.path.isfile(name)]
if writable is True:
names = [name for name in names
if self._attr_is_writable(group, name)]
elif writable is False:
names = [name for name in names
if not self._attr_is_writable(group, name)]
names.sort()
return names
def _attr_is_writable(self, group, name):
s = os.stat("%s/%s_%s" % (self._path, group, name))
return s[stat.ST_MODE] & stat.S_IWUSR
def set_attr(self, group, attribute, value):
'''
Sets the value of a named attribute.
The attribute must exist in configFS.
@param group: The attribute group
@param attribute: The attribute's name.
@param value: The attribute's value.
@type value: string
'''
self._check_self()
path = "%s/%s_%s" % (self.path, str(group), str(attribute))
if not os.path.isfile(path):
raise CFSError("Cannot find attribute: %s" % path)
if self._enable:
raise CFSError("Cannot set attribute while %s is enabled" %
self.__class__.__name__)
try:
with open(path, 'w') as file_fd:
file_fd.write(str(value))
except Exception as e:
raise CFSError("Cannot set attribute %s: %s" % (path, e))
def get_attr(self, group, attribute):
'''
Gets the value of a named attribute.
@param group: The attribute group
@param attribute: The attribute's name.
@return: The named attribute's value, as a string.
'''
self._check_self()
path = "%s/%s_%s" % (self.path, str(group), str(attribute))
if not os.path.isfile(path):
raise CFSError("Cannot find attribute: %s" % path)
with open(path, 'r') as file_fd:
return file_fd.read().strip()
def get_enable(self):
self._check_self()
path = "%s/enable" % self.path
if not os.path.isfile(path):
return None
with open(path, 'r') as file_fd:
self._enable = int(file_fd.read().strip())
return self._enable
def set_enable(self, value):
self._check_self()
path = "%s/enable" % self.path
if not os.path.isfile(path) or self._enable is None:
raise CFSError("Cannot enable %s" % self.path)
try:
with open(path, 'w') as file_fd:
file_fd.write(str(value))
except Exception as e:
raise CFSError("Cannot enable %s: %s (%s)" %
(self.path, e, value))
self._enable = value
def delete(self):
'''
If the underlying configFS object does not exist, this method does
nothing. If the underlying configFS object exists, this method attempts
to delete it.
'''
if self.exists:
os.rmdir(self.path)
path = property(_get_path,
doc="Get the configFS object path.")
exists = property(_exists,
doc="Is True as long as the underlying configFS object exists. "
+ "If the underlying configFS objects gets deleted "
+ "either by calling the delete() method, or by any "
+ "other means, it will be False.")
def dump(self):
d = {}
for group in self.attr_groups:
a = {}
for i in self.list_attrs(group, writable=True):
a[str(i)] = self.get_attr(group, i)
d[str(group)] = a
if self._enable is not None:
d['enable'] = self._enable
return d
def _setup_attrs(self, attr_dict, err_func):
for group in self.attr_groups:
for name, value in attr_dict.get(group, {}).iteritems():
try:
self.set_attr(group, name, value)
except CFSError as e:
err_func(str(e))
enable = attr_dict.get('enable')
if enable is not None:
self.set_enable(enable)
class Root(CFSNode):
def __init__(self):
super(Root, self).__init__()
if not os.path.isdir(self.configfs_dir):
self._modprobe('nvmet')
if not os.path.isdir(self.configfs_dir):
raise CFSError("%s does not exist. Giving up." %
self.configfs_dir)
self._path = self.configfs_dir
self._create_in_cfs('lookup')
def _modprobe(self, modname):
try:
from kmodpy import kmod
try:
kmod.Kmod().modprobe(modname, quiet=True)
except kmod.KmodError:
pass
except ImportError:
pass
def _list_subsystems(self):
self._check_self()
for d in os.listdir("%s/subsystems/" % self._path):
yield Subsystem(d, 'lookup')
subsystems = property(_list_subsystems,
doc="Get the list of Subsystems.")
def _list_ports(self):
self._check_self()
for d in os.listdir("%s/ports/" % self._path):
yield Port(d, 'lookup')
ports = property(_list_ports,
doc="Get the list of Ports.")
def _list_hosts(self):
self._check_self()
for h in os.listdir("%s/hosts/" % self._path):
yield Host(h, 'lookup')
hosts = property(_list_hosts,
doc="Get the list of Hosts.")
def save_to_file(self, savefile=None):
'''
Write the configuration in json format to a file.
'''
if savefile:
savefile = os.path.expanduser(savefile)
else:
savefile = DEFAULT_SAVE_FILE
savefile_abspath = os.path.abspath(savefile)
savefile_dir = os.path.dirname(savefile_abspath)
if not os.path.exists(savefile_dir):
os.makedirs(savefile_dir)
with open(savefile + ".temp", "w+") as f:
os.fchmod(f.fileno(), stat.S_IRUSR | stat.S_IWUSR)
f.write(json.dumps(self.dump(), sort_keys=True, indent=2))
f.write("\n")
f.flush()
os.fsync(f.fileno())
f.close()
os.rename(savefile + ".temp", savefile)
def clear_existing(self):
'''
Remove entire current configuration.
'''
for p in self.ports:
p.delete()
for s in self.subsystems:
s.delete()
for h in self.hosts:
h.delete()
def restore(self, config, clear_existing=False, abort_on_error=False):
'''
Takes a dict generated by dump() and reconfigures the target to match.
Returns list of non-fatal errors that were encountered.
Will refuse to restore over an existing configuration unless
clear_existing is True.
'''
if clear_existing:
self.clear_existing()
else:
if any(self.subsystems):
raise CFSError("subsystems present, not restoring")
errors = []
if abort_on_error:
def err_func(err_str):
raise CFSError(err_str)
else:
def err_func(err_str):
errors.append(err_str + ", skipped")
# Create the hosts first because the subsystems reference them
for index, t in enumerate(config.get('hosts', [])):
if 'nqn' not in t:
err_func("'nqn' not defined in host %d" % index)
continue
Host.setup(t, err_func)
for index, t in enumerate(config.get('subsystems', [])):
if 'nqn' not in t:
err_func("'nqn' not defined in subsystem %d" % index)
continue
Subsystem.setup(t, err_func)
for index, t in enumerate(config.get('ports', [])):
if 'portid' not in t:
err_func("'portid' not defined in port %d" % index)
continue
Port.setup(self, t, err_func)
return errors
def restore_from_file(self, savefile=None, clear_existing=True,
abort_on_error=False):
'''
Restore the configuration from a file in json format.
Returns a list of non-fatal errors. If abort_on_error is set,
it will raise the exception instead of continuing.
'''
if savefile:
savefile = os.path.expanduser(savefile)
else:
savefile = DEFAULT_SAVE_FILE
with open(savefile, "r") as f:
config = json.loads(f.read())
return self.restore(config, clear_existing=clear_existing,
abort_on_error=abort_on_error)
def dump(self):
d = super(Root, self).dump()
d['subsystems'] = [s.dump() for s in self.subsystems]
d['ports'] = [p.dump() for p in self.ports]
d['hosts'] = [h.dump() for h in self.hosts]
return d
class Subsystem(CFSNode):
'''
This is an interface to a NVMe Subsystem in configFS.
A Subsystem is identified by its NQN.
'''
def __repr__(self):
return "<Subsystem %s>" % self.nqn
def __init__(self, nqn=None, mode='any'):
'''
@param nqn: The Subsystems' NQN.
If no NQN is specified, one will be generated.
@type nqn: string
@param mode:An optional string containing the object creation mode:
- I{'any'} means the configFS object will be either looked up
or created.
- I{'lookup'} means the object MUST already exist configFS.
- I{'create'} means the object must NOT already exist in configFS.
@type mode:string
@return: A Subsystem object.
'''
super(Subsystem, self).__init__()
if nqn is None:
if mode == 'lookup':
raise CFSError("Need NQN for lookup")
nqn = self._generate_nqn()
self.nqn = nqn
self.attr_groups = ['attr']
self._path = "%s/subsystems/%s" % (self.configfs_dir, nqn)
self._create_in_cfs(mode)
def _generate_nqn(self):
prefix = "nqn.2014-08.org.nvmexpress:NVMf:uuid"
name = str(uuid.uuid4())
return "%s:%s" % (prefix, name)
def delete(self):
'''
Recursively deletes a Subsystem object.
This will delete all attached Namespace objects and then the
Subsystem itself.
'''
self._check_self()
for ns in self.namespaces:
ns.delete()
for h in self.allowed_hosts:
self.remove_allowed_host(h)
super(Subsystem, self).delete()
def _list_namespaces(self):
self._check_self()
for d in os.listdir("%s/namespaces/" % self._path):
yield Namespace(self, int(d), 'lookup')
namespaces = property(_list_namespaces,
doc="Get the list of Namespaces for the Subsystem.")
def _list_allowed_hosts(self):
return [os.path.basename(name)
for name in os.listdir("%s/allowed_hosts/" % self._path)]
allowed_hosts = property(_list_allowed_hosts,
doc="Get the list of Allowed Hosts for the Subsystem.")
def add_allowed_host(self, nqn):
'''
Enable access for the host identified by I{nqn} to the Subsystem
'''
try:
os.symlink("%s/hosts/%s" % (self.configfs_dir, nqn),
"%s/allowed_hosts/%s" % (self._path, nqn))
except Exception as e:
raise CFSError("Could not symlink %s in configFS: %s" % (nqn, e))
def remove_allowed_host(self, nqn):
'''
Disable access for the host identified by I{nqn} to the Subsystem
'''
try:
os.unlink("%s/allowed_hosts/%s" % (self._path, nqn))
except Exception as e:
raise CFSError("Could not unlink %s in configFS: %s" % (nqn, e))
@classmethod
def setup(cls, t, err_func):
'''
Set up Subsystem objects based upon t dict, from saved config.
Guard against missing or bad dict items, but keep going.
Call 'err_func' for each error.
'''
if 'nqn' not in t:
err_func("'nqn' not defined for Subsystem")
return
try:
s = Subsystem(t['nqn'])
except CFSError as e:
err_func("Could not create Subsystem object: %s" % e)
return
for ns in t.get('namespaces', []):
Namespace.setup(s, ns, err_func)
for h in t.get('allowed_hosts', []):
s.add_allowed_host(h)
s._setup_attrs(t, err_func)
def dump(self):
d = super(Subsystem, self).dump()
d['nqn'] = self.nqn
d['namespaces'] = [ns.dump() for ns in self.namespaces]
d['allowed_hosts'] = self.allowed_hosts
return d
class Namespace(CFSNode):
'''
This is an interface to a NVMe Namespace in configFS.
A Namespace is identified by its parent Subsystem and Namespace ID.
'''
MAX_NSID = 8192
def __repr__(self):
return "<Namespace %d>" % self.nsid
def __init__(self, subsystem, nsid=None, mode='any'):
'''
@param subsystem: The parent Subsystem object
@param nsid: The Namespace identifier
If no nsid is specified, the next free one will be used.
@type nsid: int
@param mode:An optional string containing the object creation mode:
- I{'any'} means the configFS object will be either looked up
or created.
- I{'lookup'} means the object MUST already exist configFS.
- I{'create'} means the object must NOT already exist in configFS.
@type mode:string
@return: A Namespace object.
'''
super(Namespace, self).__init__()
if not isinstance(subsystem, Subsystem):
raise CFSError("Invalid parent class")
if nsid is None:
if mode == 'lookup':
raise CFSError("Need NSID for lookup")
nsids = [n.nsid for n in subsystem.namespaces]
for index in xrange(1, self.MAX_NSID + 1):
if index not in nsids:
nsid = index
break
if nsid is None:
raise CFSError("All NSIDs 1-%d in use" % self.MAX_NSID)
else:
nsid = int(nsid)
if nsid < 1 or nsid > self.MAX_NSID:
raise CFSError("NSID must be 1 to %d" % self.MAX_NSID)
self.attr_groups = ['device']
self._subsystem = subsystem
self._nsid = nsid
self._path = "%s/namespaces/%d" % (self.subsystem.path, self.nsid)
self._create_in_cfs(mode)
def _get_subsystem(self):
return self._subsystem
def _get_nsid(self):
return self._nsid
subsystem = property(_get_subsystem,
doc="Get the parent Subsystem object.")
nsid = property(_get_nsid, doc="Get the NSID as an int.")
@classmethod
def setup(cls, subsys, n, err_func):
'''
Set up a Namespace object based upon n dict, from saved config.
Guard against missing or bad dict items, but keep going.
Call 'err_func' for each error.
'''
if 'nsid' not in n:
err_func("'nsid' not defined for Namespace")
return
try:
ns = Namespace(subsys, n['nsid'])
except CFSError as e:
err_func("Could not create Namespace object: %s" % e)
return
ns._setup_attrs(n, err_func)
def dump(self):
d = super(Namespace, self).dump()
d['nsid'] = self.nsid
return d
class Port(CFSNode):
'''
This is an interface to a NVMe Port in configFS.
'''
MAX_PORTID = 8192
def __repr__(self):
return "<Port %d>" % self.portid
def __init__(self, portid, mode='any'):
super(Port, self).__init__()
self.attr_groups = ['addr']
self._portid = int(portid)
self._path = "%s/ports/%d" % (self.configfs_dir, self._portid)
self._create_in_cfs(mode)
def _get_portid(self):
return self._portid
portid = property(_get_portid, doc="Get the Port ID as an int.")
def _list_subsystems(self):
return [os.path.basename(name)
for name in os.listdir("%s/subsystems/" % self._path)]
subsystems = property(_list_subsystems,
doc="Get the list of Subsystem for this Port.")
def add_subsystem(self, nqn):
'''
Enable access to the Subsystem identified by I{nqn} through this Port.
'''
try:
os.symlink("%s/subsystems/%s" % (self.configfs_dir, nqn),
"%s/subsystems/%s" % (self._path, nqn))
except Exception as e:
raise CFSError("Could not symlink %s in configFS: %s" % (nqn, e))
def remove_subsystem(self, nqn):
'''
Disable access to the Subsystem identified by I{nqn} through this Port.
'''
try:
os.unlink("%s/subsystems/%s" % (self._path, nqn))
except Exception as e:
raise CFSError("Could not unlink %s in configFS: %s" % (nqn, e))
def delete(self):
'''
Recursively deletes a Port object.
'''
self._check_self()
for s in self.subsystems:
self.remove_subsystem(s)
for r in self.referrals:
r.delete()
super(Port, self).delete()
def _list_referrals(self):
self._check_self()
for d in os.listdir("%s/referrals/" % self._path):
yield Referral(self, d, 'lookup')
referrals = property(_list_referrals,
doc="Get the list of Referrals for this Port.")
@classmethod
def setup(cls, root, n, err_func):
'''
Set up a Namespace object based upon n dict, from saved config.
Guard against missing or bad dict items, but keep going.
Call 'err_func' for each error.
'''
if 'portid' not in n:
err_func("'portid' not defined for Port")
return
try:
port = Port(n['portid'])
except CFSError as e:
err_func("Could not create Port object: %s" % e)
return
port._setup_attrs(n, err_func)
for s in n.get('subsystems', []):
port.add_subsystem(s)
for r in n.get('referrals', []):
Referral.setup(port, r, err_func)
def dump(self):
d = super(Port, self).dump()
d['portid'] = self.portid
d['subsystems'] = self.subsystems
d['referrals'] = [r.dump() for r in self.referrals]
return d
class Referral(CFSNode):
'''
This is an interface to a NVMe Referral in configFS.
'''
def __repr__(self):
return "<Referral %d>" % self.name
def __init__(self, port, name, mode='any'):
super(Referral, self).__init__()
if not isinstance(port, Port):
raise CFSError("Invalid parent class")
self.attr_groups = ['addr']
self.port = port
self._name = name
self._path = "%s/referrals/%s" % (self.port.path, self._name)
self._create_in_cfs(mode)
def _get_name(self):
return self._name
name = property(_get_name, doc="Get the Referral name.")
@classmethod
def setup(cls, port, n, err_func):
'''
Set up a Referral based upon n dict, from saved config.
Guard against missing or bad dict items, but keep going.
Call 'err_func' for each error.
'''
if 'name' not in n:
err_func("'name' not defined for Referral")
return
try:
r = Referral(port, n['name'])
except CFSError as e:
err_func("Could not create Referral object: %s" % e)
return
r._setup_attrs(n, err_func)
def dump(self):
d = super(Referral, self).dump()
d['name'] = self.name
return d
class Host(CFSNode):
'''
This is an interface to a NVMe Host in configFS.
A Host is identified by its NQN.
'''
def __repr__(self):
return "<Host %s>" % self.nqn
def __init__(self, nqn, mode='any'):
'''
@param nqn: The Hosts's NQN.
@type nqn: string
@param mode:An optional string containing the object creation mode:
- I{'any'} means the configFS object will be either looked up
or created.
- I{'lookup'} means the object MUST already exist configFS.
- I{'create'} means the object must NOT already exist in configFS.
@type mode:string
@return: A Host object.
'''
super(Host, self).__init__()
self.nqn = nqn
self._path = "%s/hosts/%s" % (self.configfs_dir, nqn)
self._create_in_cfs(mode)
@classmethod
def setup(cls, t, err_func):
'''
Set up Host objects based upon t dict, from saved config.
Guard against missing or bad dict items, but keep going.
Call 'err_func' for each error.
'''
if 'nqn' not in t:
err_func("'nqn' not defined for Host")
return
try:
h = Host(t['nqn'])
except CFSError as e:
err_func("Could not create Host object: %s" % e)
return
def dump(self):
d = super(Host, self).dump()
d['nqn'] = self.nqn
return d
def _test():
from doctest import testmod
testmod()
if __name__ == "__main__":
_test()