JRuby raises SystemCallError instead of Errno::EMSGSIZE

[dwbutler]

Environment

jruby -v
jruby 9.0.5.0 (2.2.3) 2016-01-26 7bee00d Java HotSpot(TM) 64-Bit Server VM 25.74-b02 on 1.8.0_74-b02 +jit [darwin-x86_64]

uname -a
Darwin Davids-MacBook-Pro-6.local 16.4.0 Darwin Kernel Version 16.4.0: Thu Dec 22 22:53:21 PST 2016; root:xnu-3789.41.3~3/RELEASE_X86_64 x86_64

Summary

JRuby raises SystemCallError instead of Errno:: EMSGSIZE when writing too large of a message to a UDP socket. See dwbutler/logstash-logger#128.

Setup

$ nc -l 5228

Ruby script (run from irb):

require 'socket'
socket = UDPSocket.new
socket.connect('127.0.0.1', 5228)
socket.write "1"*100_000

Expected Behavior

MRI 2.4.1:

Errno::EMSGSIZE: Message too long
	from (irb):4:in `write'

Actual Behavior

JRuby 9.0.5.0:

SystemCallError: Unknown error - No message available
	from org/jruby/RubyIO.java:1437:in `write'
	from org/jruby/RubyIO.java:1408:in `write'

[etehtsea]

I think I can fix this.

[kares]

and all is well ... thanks to @etehtsea

[omarmarquez]

Is this the same bug?
`$ ruby -v
jruby 9.1.16.0 (2.3.3) 2018-02-21 8f3f95a Java HotSpot(TM) 64-Bit Server VM 25.92-b14 on 1.8.0_92-b14 +jit [linux-x86_64]

$ ruby rcv.rb
SocketError: No message available
block in rcv.rb at rcv.rb:16
loop at org/jruby/RubyKernel.java:1316

at rcv.rb:15

$ cat rcv.rb
#!/usr/bin/env ruby
require 'socket'
require 'ipaddr'
BIND_ADDR = "0.0.0.0"
MULTICAST_ADDR = "239.203.120.1"
PORT = 10000

sock = UDPSocket.new
ip = IPAddr.new(MULTICAST_ADDR).hton + IPAddr.new(BIND_ADDR).hton
sock.setsockopt(Socket::IPPROTO_IP, Socket::IP_ADD_MEMBERSHIP, ip)
sock.setsockopt(Socket::SOL_SOCKET, Socket::SO_REUSEADDR, 1)
sock.bind(BIND_ADDR, PORT)
loop do
msg, info = sock.recvfrom(1024)
puts "MSG: #{msg} from #{info[2]} (#{info[3]})/#{info[1]} len #{msg.size}"
end`