From: Tanaka Akira <akr@...>
Date: 2010-06-27T13:24:44+09:00
Subject: [ruby-core:30915] Re: [Bug #3484] IO.copy_stream w/sendfile fails on 	large files under 32-bit

2010/6/26 Eric Wong <redmine@ruby-lang.org>:
>
> When IO.copy_stream uses sendfile() under 32-bit Linux, it fails for
> large files (>2G) because a single sendfile() is limited to the maximum value
> of ssize_t (LONG_MAX).  Attached is a short patch that breaks up large sendfile()
> calls and reuses the existing retry logic.

Thank you for the fix.

A script to reproduce the problem (for the record):

% cat z.rb
require 'socket'

s = Addrinfo.tcp("127.0.0.1", 0).listen

len = 4*1024*1024*1024

th = Thread.new {
  t, _ = s.accept
  buf = ""
  n = 0
  while t.read(65536, buf)
    n += buf.length
  end
  if n == len
    p :success
  else
    p [:failure, len, n]
  end
}

u = s.connect_address.connect

open("/tmp/bigtmp", "w") {|f|
  f.seek len-1
  f.print "a"
}

IO.copy_stream("/tmp/bigtmp", u)

u.close

th.join

% ./ruby -v z.rb
ruby 1.9.3dev (2010-06-27 trunk 28448) [i686-linux]
[:failure, 4294967296, 0]
-- 
Tanaka Akira