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#!/usr/bin/env python2.7
# Copyright (C) 2017 Amazon.com, Inc. or its affiliates.
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License").
# You may not use this file except in compliance with the License.
# A copy of the License is located at
#
# http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file 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.
"""
Usage:
Read EBS device information and provide information about
the volume.
"""
import argparse
from ctypes import *
from fcntl import ioctl
import sys
NVME_ADMIN_IDENTIFY = 0x06
NVME_IOCTL_ADMIN_CMD = 0xC0484E41
AMZN_NVME_VID = 0x1D0F
AMZN_NVME_EBS_MN = "Amazon Elastic Block Store"
class nvme_admin_command (Structure ):
_pack_ = 1
_fields_ = [("opcode" , c_uint8 ), # op code
("flags" , c_uint8 ), # fused operation
("cid" , c_uint16 ), # command id
("nsid" , c_uint32 ), # namespace id
("reserved0" , c_uint64 ),
("mptr" , c_uint64 ), # metadata pointer
("addr" , c_uint64 ), # data pointer
("mlen" , c_uint32 ), # metadata length
("alen" , c_uint32 ), # data length
("cdw10" , c_uint32 ),
("cdw11" , c_uint32 ),
("cdw12" , c_uint32 ),
("cdw13" , c_uint32 ),
("cdw14" , c_uint32 ),
("cdw15" , c_uint32 ),
("reserved1" , c_uint64 )]
class nvme_identify_controller_amzn_vs (Structure ):
_pack_ = 1
_fields_ = [("bdev" , c_char * 32 ), # block device name
("reserved0" , c_char * (1024 - 32 ))]
class nvme_identify_controller_psd (Structure ):
_pack_ = 1
_fields_ = [("mp" , c_uint16 ), # maximum power
("reserved0" , c_uint16 ),
("enlat" , c_uint32 ), # entry latency
("exlat" , c_uint32 ), # exit latency
("rrt" , c_uint8 ), # relative read throughput
("rrl" , c_uint8 ), # relative read latency
("rwt" , c_uint8 ), # relative write throughput
("rwl" , c_uint8 ), # relative write latency
("reserved1" , c_char * 16 )]
class nvme_identify_controller (Structure ):
_pack_ = 1
_fields_ = [("vid" , c_uint16 ), # PCI Vendor ID
("ssvid" , c_uint16 ), # PCI Subsystem Vendor ID
("sn" , c_char * 20 ), # Serial Number
("mn" , c_char * 40 ), # Module Number
("fr" , c_char * 8 ), # Firmware Revision
("rab" , c_uint8 ), # Recommend Arbitration Burst
("ieee" , c_uint8 * 3 ), # IEEE OUI Identifier
("mic" , c_uint8 ), # Multi-Interface Capabilities
("mdts" , c_uint8 ), # Maximum Data Transfer Size
("reserved0" , c_uint8 * (256 - 78 )),
("oacs" , c_uint16 ), # Optional Admin Command Support
("acl" , c_uint8 ), # Abort Command Limit
("aerl" , c_uint8 ), # Asynchronous Event Request Limit
("frmw" , c_uint8 ), # Firmware Updates
("lpa" , c_uint8 ), # Log Page Attributes
("elpe" , c_uint8 ), # Error Log Page Entries
("npss" , c_uint8 ), # Number of Power States Support
("avscc" , c_uint8 ), # Admin Vendor Specific Command Configuration
("reserved1" , c_uint8 * (512 - 265 )),
("sqes" , c_uint8 ), # Submission Queue Entry Size
("cqes" , c_uint8 ), # Completion Queue Entry Size
("reserved2" , c_uint16 ),
("nn" , c_uint32 ), # Number of Namespaces
("oncs" , c_uint16 ), # Optional NVM Command Support
("fuses" , c_uint16 ), # Fused Operation Support
("fna" , c_uint8 ), # Format NVM Attributes
("vwc" , c_uint8 ), # Volatile Write Cache
("awun" , c_uint16 ), # Atomic Write Unit Normal
("awupf" , c_uint16 ), # Atomic Write Unit Power Fail
("nvscc" , c_uint8 ), # NVM Vendor Specific Command Configuration
("reserved3" , c_uint8 * (704 - 531 )),
("reserved4" , c_uint8 * (2048 - 704 )),
("psd" , nvme_identify_controller_psd * 32 ), # Power State Descriptor
("vs" , nvme_identify_controller_amzn_vs )] # Vendor Specific
class ebs_nvme_device :
def __init__ (self , device ):
self .device = device
self .ctrl_identify ()
def _nvme_ioctl (self , id_response , id_len ):
admin_cmd = nvme_admin_command (opcode = NVME_ADMIN_IDENTIFY ,
addr = id_response ,
alen = id_len ,
cdw10 = 1 )
with open (self .device , "rw" ) as nvme :
ioctl (nvme , NVME_IOCTL_ADMIN_CMD , admin_cmd )
def ctrl_identify (self ):
self .id_ctrl = nvme_identify_controller ()
self ._nvme_ioctl (addressof (self .id_ctrl ), sizeof (self .id_ctrl ))
if self .id_ctrl .vid != AMZN_NVME_VID or self .id_ctrl .mn .strip () != AMZN_NVME_EBS_MN :
raise TypeError ("[ERROR] Not an EBS device: '{0}'" .format (self .device ))
def get_volume_id (self ):
vol = self .id_ctrl .sn
if vol .startswith ("vol" ) and vol [3 ] != "-" :
vol = "vol-" + vol [3 :]
return vol
def get_block_device (self , stripped = False ):
dev = self .id_ctrl .vs .bdev
if stripped and dev .startswith ("/dev/" ):
dev = dev [5 :]
return dev
if __name__ == "__main__" :
parser = argparse .ArgumentParser (description = "Reads EBS information from NVMe devices." )
parser .add_argument ("device" , nargs = 1 , help = "Device to query" )
display = parser .add_argument_group ("Display Options" )
display .add_argument ("-v" , "--volume" , action = "store_true" ,
help = "Return volume-id" )
display .add_argument ("-b" , "--block-dev" , action = "store_true" ,
help = "Return block device mapping" )
display .add_argument ("-u" , "--udev" , action = "store_true" ,
help = "Output data in format suitable for udev rules" )
if len (sys .argv ) < 2 :
parser .print_help ()
sys .exit (1 )
args = parser .parse_args ()
get_all = not (args .udev or args .volume or args .block_dev )
try :
dev = ebs_nvme_device (args .device [0 ])
except (IOError , TypeError ) as err :
print >> sys .stderr , err
sys .exit (1 )
if get_all or args .volume :
print "Volume ID: {0}" .format (dev .get_volume_id ())
if get_all or args .block_dev or args .udev :
print dev .get_block_device (args .udev )
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