This file is indexed.

/usr/sbin/fence_mpath is in fence-agents 4.0.22-2.

This file is owned by root:root, with mode 0o755.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
#!/usr/bin/python -tt

import sys
import stat
import re
import os
import logging
import atexit
sys.path.append("/usr/share/fence")
from fencing import fail_usage, run_command, atexit_handler, check_input, process_input, show_docs
from fencing import fence_action, all_opt, run_delay

#BEGIN_VERSION_GENERATION
RELEASE_VERSION="4.0.22"
BUILD_DATE="(built Sat, 06 Feb 2016 12:34:18 +0100)"
REDHAT_COPYRIGHT="Copyright (C) Red Hat, Inc. 2004-2010 All rights reserved."
#END_VERSION_GENERATION

def get_status(conn, options):
	del conn
	status = "off"
	for dev in options["devices"]:
		is_block_device(dev)
		if options["--key"] in get_registration_keys(options, dev):
			status = "on"
		else:
			logging.debug("No registration for key "\
				+ options["--key"] + " on device " + dev + "\n")

	if options["--action"] == "monitor":
		dev_read(options)

	return status


def set_status(conn, options):
	del conn
	count = 0
	if options["--action"] == "on":
		for dev in options["devices"]:
			is_block_device(dev)

			register_dev(options, dev)
			if options["--key"] not in get_registration_keys(options, dev):
				count += 1
				logging.debug("Failed to register key "\
					+ options["--key"] + "on device " + dev + "\n")
				continue
			dev_write(options, dev)

			if get_reservation_key(options, dev) is None \
			and not reserve_dev(options, dev) \
			and get_reservation_key(options, dev) is None:
				count += 1
				logging.debug("Failed to create reservation (key="\
					+ options["--key"] + ", device=" + dev + ")\n")

	else:
		dev_keys = dev_read(options)

		for dev in options["devices"]:
			is_block_device(dev)

			if options["--key"] in get_registration_keys(options, dev):
				preempt_abort(options, dev_keys[dev], dev)

		for dev in options["devices"]:
			if options["--key"] in get_registration_keys(options, dev):
				count += 1
				logging.debug("Failed to remove key "\
					+ options["--key"] + " on device " + dev + "\n")
				continue

			if not get_reservation_key(options, dev):
				count += 1
				logging.debug("No reservation exists on device " + dev + "\n")
	if count:
		logging.error("Failed to verify " + str(count) + " device(s)")
		sys.exit(1)


#run command, returns dict, ret["err"] = exit code; ret["out"] = output
def run_cmd(options, cmd):
	ret = {}

	if options.has_key("--use-sudo"):
		prefix = options["--sudo-path"] + " "
	else:
		prefix = ""

	(ret["err"], ret["out"], _) = run_command(options, prefix + cmd)
	ret["out"] = "".join([i for i in ret["out"] if i is not None])
	return ret


# check if device exist and is block device
def is_block_device(dev):
	if not os.path.exists(dev):
		fail_usage("Failed: device \"" + dev + "\" does not exist")
	if not stat.S_ISBLK(os.stat(dev).st_mode):
		fail_usage("Failed: device \"" + dev + "\" is not a block device")

# cancel registration
def preempt_abort(options, host, dev):
	cmd = options["--mpathpersist-path"] + " -o --preempt-abort --prout-type=5 --param-rk=" + host +" --param-sark=" + options["--key"] +"-d " + dev
	return not bool(run_cmd(options, cmd)["err"])

def register_dev(options, dev):
	cmd = options["--mpathpersist-path"] + " -o --register --param-sark=" + options["--key"] + " -d " + dev
	#cmd return code != 0 but registration can be successful
	return not bool(run_cmd(options, cmd)["err"])

def reserve_dev(options, dev):
	cmd = options["--mpathpersist-path"] + " -o --reserv --prout-type=5 --param-rk=" + options["--key"] + " -d " + dev
	return not bool(run_cmd(options, cmd)["err"])

def get_reservation_key(options, dev):
	cmd = options["--mpathpersist-path"] + " -i -r -d " + dev
	out = run_cmd(options, cmd)
	if out["err"]:
		fail_usage("Cannot get reservation key")
	match = re.search(r"\s+key\s*=\s*0x(\S+)\s+", out["out"], re.IGNORECASE)
	return match.group(1) if match else None

def get_registration_keys(options, dev):
	keys = []
	cmd = options["--mpathpersist-path"] + " -i -k -d " + dev
	out = run_cmd(options, cmd)
	if out["err"]:
		fail_usage("Cannot get registration keys")
	for line in out["out"].split("\n"):
		match = re.search(r"\s+0x(\S+)\s*", line)
		if match:
			keys.append(match.group(1))
	return keys

def dev_write(options, dev):
	file_path = options["--store-path"] + "/mpath.devices"

	if not os.path.isdir(options["--store-path"]):
		os.makedirs(options["--store-path"])

	try:
		store_fh = open(file_path, "a+")
	except IOError:
		fail_usage("Failed: Cannot open file \""+ file_path + "\"")
	out = store_fh.read()
	if not re.search(r"^" + dev + r"\s+", out):
		store_fh.write(dev + "\t" + options["--key"] + "\n")
	store_fh.close()

def dev_read(options):
	dev_key = {}
	file_path = options["--store-path"] + "/mpath.devices"
	try:
		store_fh = open(file_path, "r")
	except IOError:
		fail_usage("Failed: Cannot open file \"" + file_path + "\"")
	# get not empty lines from file
	for (device, key) in [line.strip().split() for line in store_fh if line.strip()]:
		dev_key[device] = key
	store_fh.close()
	return dev_key

def define_new_opts():
	all_opt["devices"] = {
		"getopt" : "d:",
		"longopt" : "devices",
		"help" : "-d, --devices=[devices]        List of devices to use for current operation",
		"required" : "1",
		"shortdesc" : "List of devices to use for current operation. Devices can \
be comma-separated list of device-mapper multipath devices (eg. /dev/dm-3). \
Each device must support SCSI-3 persistent reservations.",
		"order": 1
	}
	all_opt["key"] = {
		"getopt" : "k:",
		"longopt" : "key",
		"help" : "-k, --key=[key]                Key to use for the current operation",
		"required" : "1",
		"shortdesc" : "Key to use for the current operation. This key should be \
unique to a node and have to be written in /etc/multipath.conf. For the \"on\" action, the key specifies the key use to \
register the local node. For the \"off\" action, this key specifies the key to \
be removed from the device(s).",
		"order": 1
	}
	all_opt["mpathpersist_path"] = {
		"getopt" : ":",
		"longopt" : "mpathpersist-path",
		"help" : "--mpathpersist-path=[path]     Path to mpathpersist binary",
		"required" : "0",
		"shortdesc" : "Path to mpathpersist binary",
		"default" : "/usr/sbin/mpathpersist",
		"order": 200
	}
	all_opt["store_path"] = {
		"getopt" : ":",
		"longopt" : "store-path",
		"help" : "--store-path=[path]            Path to directory containing cached keys",
		"required" : "0",
		"shortdesc" : "Path to directory where fence agent can store information",
		"default" : "/var/run/cluster",
		"order": 200
	}

def main():
	atexit.register(atexit_handler)

	device_opt = ["no_login", "no_password", "devices", "key", "sudo", \
	        "fabric_fencing", "on_target", "store_path", "mpathpersist_path", "force_on"]

	define_new_opts()

	options = check_input(device_opt, process_input(device_opt), other_conditions=True)

	docs = {}
	docs["shortdesc"] = "Fence agent for multipath persistent reservation"
	docs["longdesc"] = "fence_mpath is an I/O fencing agent that uses SCSI-3 \
persistent reservations to control access multipath devices. Underlying \
devices must support SCSI-3 persistent reservations (SPC-3 or greater) as \
well as the \"preempt-and-abort\" subcommand.\nThe fence_mpath agent works by \
having an unique key for each pair of node and device that has to be set also \
in /etc/multipath.conf. Once registered, a single node will become the reservation holder \
by creating a \"write exclusive, registrants only\" reservation on the \
device(s). The result is that only registered nodes may write to the \
device(s). When a node failure occurs, the fence_mpath agent will remove the \
key belonging to the failed node from the device(s). The failed node will no \
longer be able to write to the device(s). A manual reboot is required."
	docs["vendorurl"] = "https://www.sourceware.org/dm/"
	show_docs(options, docs)

	run_delay(options)

	# Input control BEGIN
	if not "--key" in options:
		fail_usage("Failed: key is required")

	if options["--action"] == "validate-all":
		sys.exit(0)

	options["devices"] = options["--devices"].split(",")

	if not options["devices"]:
		fail_usage("Failed: No devices found")
	# Input control END

	result = fence_action(None, options, set_status, get_status)
	sys.exit(result)

if __name__ == "__main__":
	main()