* lib/resolv.rb (Resolv::DNS): retry IO.select for premature wakeup.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@33584 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,7 @@
+Mon Oct 31 21:02:43 2011  Tanaka Akira  <akr@fsij.org>
+
+	* lib/resolv.rb (Resolv::DNS): retry IO.select for premature wakeup.
+
 Mon Oct 31 20:14:22 2011  Tanaka Akira  <akr@fsij.org>
 
 	* io.c (fd_set_cloexec): clear CLOEXEC flag for standard file

lib/resolv.rb

@@ -657,16 +657,19 @@ class Resolv
       end
 
       def request(sender, tout)
-        timelimit = Time.now + tout
+        start = Time.now
+        timelimit = start + tout
         sender.send
         while true
-          now = Time.now
-          timeout = timelimit - now
+          before_select = Time.now
+          timeout = timelimit - before_select
           if timeout <= 0
             raise ResolvTimeout
           end
           select_result = IO.select(@socks, nil, nil, timeout)
           if !select_result
+            after_select = Time.now
+            next if after_select < timelimit
             raise ResolvTimeout
           end
           begin

test/resolv/test_dns.rb

@@ -114,7 +114,8 @@ class TestResolvDNS < Test::Unit::TestCase
         start = Time.now
         dns.getresources("foo.example.org", Resolv::DNS::Resource::IN::A)
       }
-      diff = Time.now - start
+      t2 = Time.now
+      diff = t2 - start
       assert rv.empty?, "unexpected: #{rv.inspect} (expected empty)"
       assert_operator 0.1, :<=, diff
 
@@ -123,7 +124,8 @@ class TestResolvDNS < Test::Unit::TestCase
         start = Time.now
         dns.getresources("foo.example.org", Resolv::DNS::Resource::IN::A)
       }
-      diff = Time.now - start
+      t2 = Time.now
+      diff = t2 - start
       assert rv.empty?, "unexpected: #{rv.inspect} (expected empty)"
       assert_operator 0.3, :<=, diff
     }