# frozen_string_literal: false
#
# utils.rb -- Miscellaneous utilities
#
# Author: IPR -- Internet Programming with Ruby -- writers
# Copyright (c) 2001 TAKAHASHI Masayoshi, GOTOU Yuuzou
# Copyright (c) 2002 Internet Programming with Ruby writers. All rights
# reserved.
#
# $IPR: utils.rb,v 1.10 2003/02/16 22:22:54 gotoyuzo Exp $
require 'socket'
require 'io/nonblock'
require 'etc'
module WEBrick
module Utils
##
# Sets IO operations on +io+ to be non-blocking
def set_non_blocking(io)
io.nonblock = true if io.respond_to?(:nonblock=)
end
module_function :set_non_blocking
##
# Sets the close on exec flag for +io+
def set_close_on_exec(io)
io.close_on_exec = true if io.respond_to?(:close_on_exec=)
end
module_function :set_close_on_exec
##
# Changes the process's uid and gid to the ones of +user+
def su(user)
if pw = Etc.getpwnam(user)
Process::initgroups(user, pw.gid)
Process::Sys::setgid(pw.gid)
Process::Sys::setuid(pw.uid)
else
warn("WEBrick::Utils::su doesn't work on this platform", uplevel: 1)
end
end
module_function :su
##
# The server hostname
def getservername
host = Socket::gethostname
begin
Socket::gethostbyname(host)[0]
rescue
host
end
end
module_function :getservername
##
# Creates TCP server sockets bound to +address+:+port+ and returns them.
#
# It will create IPV4 and IPV6 sockets on all interfaces.
def create_listeners(address, port)
unless port
raise ArgumentError, "must specify port"
end
sockets = Socket.tcp_server_sockets(address, port)
sockets = sockets.map {|s|
s.autoclose = false
ts = TCPServer.for_fd(s.fileno)
s.close
ts
}
return sockets
end
module_function :create_listeners
##
# Characters used to generate random strings
RAND_CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
"0123456789" +
"abcdefghijklmnopqrstuvwxyz"
##
# Generates a random string of length +len+
def random_string(len)
rand_max = RAND_CHARS.bytesize
ret = ""
len.times{ ret << RAND_CHARS[rand(rand_max)] }
ret
end
module_function :random_string
###########
require "timeout"
require "singleton"
##
# Class used to manage timeout handlers across multiple threads.
#
# Timeout handlers should be managed by using the class methods which are
# synchronized.
#
# id = TimeoutHandler.register(10, Timeout::Error)
# begin
# sleep 20
# puts 'foo'
# ensure
# TimeoutHandler.cancel(id)
# end
#
# will raise Timeout::Error
#
# id = TimeoutHandler.register(10, Timeout::Error)
# begin
# sleep 5
# puts 'foo'
# ensure
# TimeoutHandler.cancel(id)
# end
#
# will print 'foo'
#
class TimeoutHandler
include Singleton
##
# Mutex used to synchronize access across threads
TimeoutMutex = Thread::Mutex.new # :nodoc:
##
# Registers a new timeout handler
#
# +time+:: Timeout in seconds
# +exception+:: Exception to raise when timeout elapsed
def TimeoutHandler.register(seconds, exception)
at = Process.clock_gettime(Process::CLOCK_MONOTONIC) + seconds
instance.register(Thread.current, at, exception)
end
##
# Cancels the timeout handler +id+
def TimeoutHandler.cancel(id)
instance.cancel(Thread.current, id)
end
def self.terminate
instance.terminate
end
##
# Creates a new TimeoutHandler. You should use ::register and ::cancel
# instead of creating the timeout handler directly.
def initialize
TimeoutMutex.synchronize{
@timeout_info = Hash.new
}
@queue = Thread::Queue.new
@watcher = nil
end
# :nodoc:
private \
def watch
to_interrupt = []
while true
now = Process.clock_gettime(Process::CLOCK_MONOTONIC)
wakeup = nil
to_interrupt.clear
TimeoutMutex.synchronize{
@timeout_info.each {|thread, ary|
next unless ary
ary.each{|info|
time, exception = *info
if time < now
to_interrupt.push [thread, info.object_id, exception]
elsif !wakeup || time < wakeup
wakeup = time
end
}
}
}
to_interrupt.each {|arg| interrupt(*arg)}
if !wakeup
@queue.pop
elsif (wakeup -= now) > 0
begin
(th = Thread.start {@queue.pop}).join(wakeup)
ensure
th&.kill&.join
end
end
@queue.clear
end
end
# :nodoc:
private \
def watcher
(w = @watcher)&.alive? and return w # usual case
TimeoutMutex.synchronize{
(w = @watcher)&.alive? and next w # pathological check
@watcher = Thread.start(&method(:watch))
}
end
##
# Interrupts the timeout handler +id+ and raises +exception+
def interrupt(thread, id, exception)
if cancel(thread, id) && thread.alive?
thread.raise(exception, "execution timeout")
end
end
##
# Registers a new timeout handler
#
# +time+:: Timeout in seconds
# +exception+:: Exception to raise when timeout elapsed
def register(thread, time, exception)
info = nil
TimeoutMutex.synchronize{
(@timeout_info[thread] ||= []) << (info = [time, exception])
}
@queue.push nil
watcher
return info.object_id
end
##
# Cancels the timeout handler +id+
def cancel(thread, id)
TimeoutMutex.synchronize{
if ary = @timeout_info[thread]
ary.delete_if{|info| info.object_id == id }
if ary.empty?
@timeout_info.delete(thread)
end
return true
end
return false
}
end
##
def terminate
TimeoutMutex.synchronize{
@timeout_info.clear
@watcher&.kill&.join
}
end
end
##
# Executes the passed block and raises +exception+ if execution takes more
# than +seconds+.
#
# If +seconds+ is zero or nil, simply executes the block
def timeout(seconds, exception=Timeout::Error)
return yield if seconds.nil? or seconds.zero?
# raise ThreadError, "timeout within critical session" if Thread.critical
id = TimeoutHandler.register(seconds, exception)
begin
yield(seconds)
ensure
TimeoutHandler.cancel(id)
end
end
module_function :timeout
end
end