/usr/lib/ruby/vendor_ruby/lockfile.rb is in ruby-lockfile 2.1.3-1.
This file is owned by root:root, with mode 0o644.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 | unless(defined?($__lockfile__) or defined?(Lockfile))
require 'socket'
require 'timeout'
require 'fileutils'
class Lockfile
VERSION = '2.1.3'
def Lockfile.version() Lockfile::VERSION end
def version() Lockfile::VERSION end
def Lockfile.description
'a ruby library for creating perfect and NFS safe lockfiles'
end
class LockError < StandardError; end
class StolenLockError < LockError; end
class StackingLockError < LockError; end
class StatLockError < LockError; end
class MaxTriesLockError < LockError; end
class TimeoutLockError < LockError; end
class NFSLockError < LockError; end
class UnLockError < LockError; end
class SleepCycle < Array
attr_reader :min
attr_reader :max
attr_reader :range
attr_reader :inc
def initialize(min, max, inc)
@min, @max, @inc = Float(min), Float(max), Float(inc)
@range = @max - @min
raise RangeError, "max(#{ @max }) <= min(#{ @min })" if @max <= @min
raise RangeError, "inc(#{ @inc }) > range(#{ @range })" if @inc > @range
raise RangeError, "inc(#{ @inc }) <= 0" if @inc <= 0
raise RangeError, "range(#{ @range }) <= 0" if @range <= 0
s = @min
push(s) and s += @inc while(s <= @max)
self[-1] = @max if self[-1] < @max
reset
end
def next
ret = self[@idx]
@idx = ((@idx + 1) % self.size)
ret
end
def reset
@idx = 0
end
end
HOSTNAME = Socket.gethostname
DEFAULT_RETRIES = nil # maximum number of attempts
DEFAULT_TIMEOUT = nil # the longest we will try
DEFAULT_MAX_AGE = 3600 # lockfiles older than this are stale
DEFAULT_SLEEP_INC = 2 # sleep cycle is this much longer each time
DEFAULT_MIN_SLEEP = 2 # shortest sleep time
DEFAULT_MAX_SLEEP = 32 # longest sleep time
DEFAULT_SUSPEND = 1800 # iff we steal a lock wait this long before we go on
DEFAULT_REFRESH = 8 # how often we touch/validate the lock
DEFAULT_DONT_CLEAN = false # iff we leave lock files lying around
DEFAULT_POLL_RETRIES = 16 # this many polls makes one 'try'
DEFAULT_POLL_MAX_SLEEP = 0.08 # the longest we'll sleep between polls
DEFAULT_DONT_SWEEP = false # if we cleanup after other process on our host
DEFAULT_DONT_USE_LOCK_ID = false # if we dump lock info into lockfile
DEFAULT_DEBUG = ENV['LOCKFILE_DEBUG'] || false
class << Lockfile
attr_accessor :retries
attr_accessor :max_age
attr_accessor :sleep_inc
attr_accessor :min_sleep
attr_accessor :max_sleep
attr_accessor :suspend
attr_accessor :timeout
attr_accessor :refresh
attr_accessor :debug
attr_accessor :dont_clean
attr_accessor :poll_retries
attr_accessor :poll_max_sleep
attr_accessor :dont_sweep
attr_accessor :dont_use_lock_id
def init
@retries = DEFAULT_RETRIES
@max_age = DEFAULT_MAX_AGE
@sleep_inc = DEFAULT_SLEEP_INC
@min_sleep = DEFAULT_MIN_SLEEP
@max_sleep = DEFAULT_MAX_SLEEP
@suspend = DEFAULT_SUSPEND
@timeout = DEFAULT_TIMEOUT
@refresh = DEFAULT_REFRESH
@dont_clean = DEFAULT_DONT_CLEAN
@poll_retries = DEFAULT_POLL_RETRIES
@poll_max_sleep = DEFAULT_POLL_MAX_SLEEP
@dont_sweep = DEFAULT_DONT_SWEEP
@dont_use_lock_id = DEFAULT_DONT_USE_LOCK_ID
@debug = DEFAULT_DEBUG
STDOUT.sync = true if @debug
STDERR.sync = true if @debug
end
end
Lockfile.init
attr_reader :klass
attr_reader :path
attr_reader :opts
attr_reader :locked
attr_reader :thief
attr_reader :refresher
attr_reader :dirname
attr_reader :basename
attr_reader :clean
attr_reader :retries
attr_reader :max_age
attr_reader :sleep_inc
attr_reader :min_sleep
attr_reader :max_sleep
attr_reader :suspend
attr_reader :refresh
attr_reader :timeout
attr_reader :dont_clean
attr_reader :poll_retries
attr_reader :poll_max_sleep
attr_reader :dont_sweep
attr_reader :dont_use_lock_id
attr_accessor :debug
alias thief? thief
alias locked? locked
alias debug? debug
def Lockfile.create(path, *a, &b)
opts = {
'retries' => 0,
'min_sleep' => 0,
'max_sleep' => 1,
'sleep_inc' => 1,
'max_age' => nil,
'suspend' => 0,
'refresh' => nil,
'timeout' => nil,
'poll_retries' => 0,
'dont_clean' => true,
'dont_sweep' => false,
'dont_use_lock_id' => true,
}
begin
new(path, opts).lock
rescue LockError
raise Errno::EEXIST, path
end
open(path, *a, &b)
end
def initialize(path, opts = {}, &block)
@klass = self.class
@path = path
@opts = opts
@retries = getopt 'retries' , @klass.retries
@max_age = getopt 'max_age' , @klass.max_age
@sleep_inc = getopt 'sleep_inc' , @klass.sleep_inc
@min_sleep = getopt 'min_sleep' , @klass.min_sleep
@max_sleep = getopt 'max_sleep' , @klass.max_sleep
@suspend = getopt 'suspend' , @klass.suspend
@timeout = getopt 'timeout' , @klass.timeout
@refresh = getopt 'refresh' , @klass.refresh
@dont_clean = getopt 'dont_clean' , @klass.dont_clean
@poll_retries = getopt 'poll_retries' , @klass.poll_retries
@poll_max_sleep = getopt 'poll_max_sleep' , @klass.poll_max_sleep
@dont_sweep = getopt 'dont_sweep' , @klass.dont_sweep
@dont_use_lock_id = getopt 'dont_use_lock_id' , @klass.dont_use_lock_id
@debug = getopt 'debug' , @klass.debug
@sleep_cycle = SleepCycle.new @min_sleep, @max_sleep, @sleep_inc
@clean = @dont_clean ? nil : lambda{ File.unlink @path rescue nil }
@dirname = File.dirname @path
@basename = File.basename @path
@thief = false
@locked = false
@refrsher = nil
lock(&block) if block
end
##
# Executes the given block after acquiring the lock and
# ensures that the lock is relinquished afterwards.
#
def synchronize
raise ArgumentError, 'block must be given' unless block_given?
begin
lock
yield
ensure
unlock
end
end
def lock
raise StackingLockError, "<#{ @path }> is locked!" if @locked
sweep unless @dont_sweep
ret = nil
attempt do
begin
@sleep_cycle.reset
create_tmplock do |f|
begin
Timeout.timeout(@timeout) do
tmp_path = f.path
tmp_stat = f.lstat
n_retries = 0
trace{ "attempting to lock <#{ @path }>..." }
begin
i = 0
begin
trace{ "polling attempt <#{ i }>..." }
begin
File.link tmp_path, @path
rescue Errno::ENOENT
try_again!
end
lock_stat = File.lstat @path
raise StatLockError, "stat's do not agree" unless
tmp_stat.rdev == lock_stat.rdev and tmp_stat.ino == lock_stat.ino
trace{ "aquired lock <#{ @path }>" }
@locked = true
rescue => e
i += 1
unless i >= @poll_retries
t = [rand(@poll_max_sleep), @poll_max_sleep].min
trace{ "poll sleep <#{ t }>..." }
sleep t
retry
end
raise
end
rescue => e
n_retries += 1
trace{ "n_retries <#{ n_retries }>" }
case validlock?
when true
raise MaxTriesLockError, "surpased retries <#{ @retries }>" if
@retries and n_retries >= @retries
trace{ "found valid lock" }
sleeptime = @sleep_cycle.next
trace{ "sleep <#{ sleeptime }>..." }
sleep sleeptime
when false
trace{ "found invalid lock and removing" }
begin
File.unlink @path
@thief = true
warn "<#{ @path }> stolen by <#{ Process.pid }> at <#{ timestamp }>"
trace{ "i am a thief!" }
rescue Errno::ENOENT
end
trace{ "suspending <#{ @suspend }>" }
sleep @suspend
when nil
raise MaxTriesLockError, "surpased retries <#{ @retries }>" if
@retries and n_retries >= @retries
end
retry
end # begin
end # timeout
rescue Timeout::Error
raise TimeoutLockError, "surpassed timeout <#{ @timeout }>"
end # begin
end # create_tmplock
if block_given?
stolen = false
@refresher = (@refresh ? new_refresher : nil)
begin
begin
ret = yield @path
rescue StolenLockError
stolen = true
raise
end
ensure
begin
@refresher.kill if @refresher and @refresher.status
@refresher = nil
ensure
unlock unless stolen
end
end
else
@refresher = (@refresh ? new_refresher : nil)
ObjectSpace.define_finalizer self, @clean if @clean
ret = self
end
rescue Errno::ESTALE, Errno::EIO => e
raise(NFSLockError, errmsg(e))
end
end
return ret
end
def sweep
begin
glob = File.join(@dirname, ".*lck")
paths = Dir[glob]
paths.each do |path|
begin
basename = File.basename path
pat = %r/^\s*\.([^_]+)_([^_]+)/o
if pat.match(basename)
host, pid = $1, $2
else
next
end
host.gsub!(%r/^\.+|\.+$/,'')
quad = host.split %r/\./
host = quad.first
pat = %r/^\s*#{ host }/i
if pat.match(HOSTNAME) and %r/^\s*\d+\s*$/.match(pid)
unless alive?(pid)
trace{ "process <#{ pid }> on <#{ host }> is no longer alive" }
trace{ "sweeping <#{ path }>" }
FileUtils.rm_f path
else
trace{ "process <#{ pid }> on <#{ host }> is still alive" }
trace{ "ignoring <#{ path }>" }
end
else
trace{ "ignoring <#{ path }> generated by <#{ host }>" }
end
rescue
next
end
end
rescue => e
warn(errmsg(e))
end
end
def alive? pid
pid = Integer("#{ pid }")
begin
Process.kill 0, pid
true
rescue Errno::ESRCH
false
end
end
def unlock
raise UnLockError, "<#{ @path }> is not locked!" unless @locked
@refresher.kill if @refresher and @refresher.status
@refresher = nil
begin
File.unlink @path
rescue Errno::ENOENT
raise StolenLockError, @path
ensure
@thief = false
@locked = false
ObjectSpace.undefine_finalizer self if @clean
end
end
def new_refresher
Thread.new(Thread.current, @path, @refresh, @dont_use_lock_id) do |thread, path, refresh, dont_use_lock_id|
loop do
begin
touch path
trace{"touched <#{ path }> @ <#{ Time.now.to_f }>"}
unless dont_use_lock_id
loaded = load_lock_id(IO.read(path))
trace{"loaded <\n#{ loaded.inspect }\n>"}
raise unless loaded == @lock_id
end
sleep refresh
rescue Exception => e
trace{errmsg e}
thread.raise StolenLockError
Thread.exit
end
end
end
end
def validlock?
if @max_age
uncache @path rescue nil
begin
return((Time.now - File.stat(@path).mtime) < @max_age)
rescue Errno::ENOENT
return nil
end
else
exist = File.exist?(@path)
return(exist ? true : nil)
end
end
def uncache file
refresh = nil
begin
is_a_file = File === file
path = (is_a_file ? file.path : file.to_s)
stat = (is_a_file ? file.stat : File.stat(file.to_s))
refresh = tmpnam(File.dirname(path))
File.link path, refresh
File.chmod stat.mode, path
File.utime stat.atime, stat.mtime, path
ensure
begin
File.unlink refresh if refresh
rescue Errno::ENOENT
end
end
end
def create_tmplock
tmplock = tmpnam @dirname
begin
create(tmplock) do |f|
unless dont_use_lock_id
@lock_id = gen_lock_id
dumped = dump_lock_id
trace{"lock_id <\n#{ @lock_id.inspect }\n>"}
f.write dumped
f.flush
end
yield f
end
ensure
begin; File.unlink tmplock; rescue Errno::ENOENT; end if tmplock
end
end
def gen_lock_id
Hash[
'host' => "#{ HOSTNAME }",
'pid' => "#{ Process.pid }",
'ppid' => "#{ Process.ppid }",
'time' => timestamp,
]
end
def timestamp
time = Time.now
usec = time.usec.to_s
usec << '0' while usec.size < 6
"#{ time.strftime('%Y-%m-%d %H:%M:%S') }.#{ usec }"
end
def dump_lock_id(lock_id = @lock_id)
"host: %s\npid: %s\nppid: %s\ntime: %s\n" %
lock_id.values_at('host','pid','ppid','time')
end
def load_lock_id(buf)
lock_id = {}
kv = %r/([^:]+):(.*)/o
buf.each_line do |line|
m = kv.match line
k, v = m[1], m[2]
next unless m and k and v
lock_id[k.strip] = v.strip
end
lock_id
end
def tmpnam(dir, seed = File.basename($0))
pid = Process.pid
time = Time.now
sec = time.to_i
usec = time.usec
"%s%s.%s_%d_%s_%d_%d_%d.lck" %
[dir, File::SEPARATOR, HOSTNAME, pid, seed, sec, usec, rand(sec)]
end
def create(path)
umask = nil
f = nil
begin
umask = File.umask 022
f = open path, File::WRONLY|File::CREAT|File::EXCL, 0644
ensure
File.umask umask if umask
end
return(block_given? ? begin; yield f; ensure; f.close; end : f)
end
def touch(path)
FileUtils.touch path
end
def getopt(key, default = nil)
[ key, key.to_s, key.to_s.intern ].each do |k|
return @opts[k] if @opts.has_key?(k)
end
return default
end
def to_str
@path
end
alias to_s to_str
def trace(s = nil)
STDERR.puts((s ? s : yield)) if @debug
end
def errmsg(e)
"%s (%s)\n%s\n" % [e.class, e.message, e.backtrace.join("\n")]
end
def attempt
ret = nil
loop{ break unless catch('attempt'){ ret = yield } == 'try_again' }
ret
end
def try_again!
throw 'attempt', 'try_again'
end
alias again! try_again!
def give_up!
throw 'attempt', 'give_up'
end
end
def Lockfile(path, *a, &b)
Lockfile.new(path, *a, &b)
end
$__lockfile__ = __FILE__
end
|