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resolv.rb: close socket

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* lib/resolv.rb (UnconnectedUDP#lazy_initialize): store new
  sockets before binding, so the sockets get closed when the
  requester is closing.

* lib/resolv.rb (ConnectedUDP#lazy_initialize): ditto.

* lib/resolv.rb (UnconnectedUDP#close): synchronize to get rid of
  race condition.

* lib/resolv.rb (ConnectedUDP#close): ditto.

[ruby-core:85901] [Bug #14571]

From: quixoten (Devin Christensen) <quixoten@gmail.com>

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62671 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
nobu 2018-03-06 02:48:17 +00:00
parent 4b747c2890
commit e6c0a8f19e
2 changed files with 88 additions and 33 deletions
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102
lib/resolv.rb
View File

@ -732,35 +732,47 @@ class Resolv
def initialize(*nameserver_port)
super()
@nameserver_port = nameserver_port
@socks_hash = {}
@socks = []
nameserver_port.each {|host, port|
if host.index(':')
bind_host = "::"
af = Socket::AF_INET6
else
bind_host = "0.0.0.0"
af = Socket::AF_INET
end
next if @socks_hash[bind_host]
begin
sock = UDPSocket.new(af)
rescue Errno::EAFNOSUPPORT
next # The kernel doesn't support the address family.
end
sock.do_not_reverse_lookup = true
DNS.bind_random_port(sock, bind_host)
@socks << sock
@socks_hash[bind_host] = sock
@initialized = false
@mutex = Thread::Mutex.new
end
def lazy_initialize
@mutex.synchronize {
next if @initialized
@initialized = true
@socks_hash = {}
@socks = []
@nameserver_port.each {|host, port|
if host.index(':')
bind_host = "::"
af = Socket::AF_INET6
else
bind_host = "0.0.0.0"
af = Socket::AF_INET
end
next if @socks_hash[bind_host]
begin
sock = UDPSocket.new(af)
rescue Errno::EAFNOSUPPORT
next # The kernel doesn't support the address family.
end
@socks << sock
@socks_hash[bind_host] = sock
sock.do_not_reverse_lookup = true
DNS.bind_random_port(sock, bind_host)
}
}
self
end
def recv_reply(readable_socks)
lazy_initialize
reply, from = readable_socks[0].recvfrom(UDPSize)
return reply, [from[3],from[1]]
end
def sender(msg, data, host, port=Port)
lazy_initialize
sock = @socks_hash[host.index(':') ? "::" : "0.0.0.0"]
return nil if !sock
service = [host, port]
@ -772,9 +784,14 @@ class Resolv
end
def close
super
@senders.each_key {|service, id|
DNS.free_request_id(service[0], service[1], id)
@mutex.synchronize {
if @initialized
super
@senders.each_key {|service, id|
DNS.free_request_id(service[0], service[1], id)
}
@initialized = false
end
}
end
@ -798,20 +815,32 @@ class Resolv
super()
@host = host
@port = port
is_ipv6 = host.index(':')
sock = UDPSocket.new(is_ipv6 ? Socket::AF_INET6 : Socket::AF_INET)
@socks = [sock]
sock.do_not_reverse_lookup = true
DNS.bind_random_port(sock, is_ipv6 ? "::" : "0.0.0.0")
sock.connect(host, port)
@mutex = Thread::Mutex.new
@initialized = false
end
def lazy_initialize
@mutex.synchronize {
next if @initialized
@initialized = true
is_ipv6 = @host.index(':')
sock = UDPSocket.new(is_ipv6 ? Socket::AF_INET6 : Socket::AF_INET)
@socks = [sock]
sock.do_not_reverse_lookup = true
DNS.bind_random_port(sock, is_ipv6 ? "::" : "0.0.0.0")
sock.connect(@host, @port)
}
self
end
def recv_reply(readable_socks)
lazy_initialize
reply = readable_socks[0].recv(UDPSize)
return reply, nil
end
def sender(msg, data, host=@host, port=@port)
lazy_initialize
unless host == @host && port == @port
raise RequestError.new("host/port don't match: #{host}:#{port}")
end
@ -822,10 +851,15 @@ class Resolv
end
def close
super
@senders.each_key {|from, id|
DNS.free_request_id(@host, @port, id)
}
@mutex.synchronize do
if @initialized
super
@senders.each_key {|from, id|
DNS.free_request_id(@host, @port, id)
}
@initialized = false
end
end
end
class Sender < Requester::Sender # :nodoc:
@ -839,6 +873,7 @@ class Resolv
class MDNSOneShot < UnconnectedUDP # :nodoc:
def sender(msg, data, host, port=Port)
lazy_initialize
id = DNS.allocate_request_id(host, port)
request = msg.encode
request[0,2] = [id].pack('n')
@ -848,6 +883,7 @@ class Resolv
end
def sender_for(addr, msg)
lazy_initialize
@senders[msg.id]
end
end

19
test/resolv/test_dns.rb
View File

@ -3,6 +3,7 @@ require 'test/unit'
require 'resolv'
require 'socket'
require 'tempfile'
require 'minitest/mock'
class TestResolvDNS < Test::Unit::TestCase
def setup
@ -246,4 +247,22 @@ class TestResolvDNS < Test::Unit::TestCase
}
assert_operator(2**14, :<, m.to_s.length)
end
def assert_no_fd_leak
socket = assert_throw(self) do |tag|
Resolv::DNS.stub(:bind_random_port, ->(s, *) {throw(tag, s)}) do
yield.getname("8.8.8.8")
end
end
assert_predicate(socket, :closed?, "file descriptor leaked")
end
def test_no_fd_leak_connected
assert_no_fd_leak {Resolv::DNS.new(nameserver_port: [['127.0.0.1', 53]])}
end
def test_no_fd_leak_unconnected
assert_no_fd_leak {Resolv::DNS.new}
end
end