On 20.11.2013 18:38, Dmitry Samersoff wrote:
Roger,
As soon as we close a socket nobody can guarantee that the port is free.
Moreover, port returned by getFreePort()[1] remains not accessible for
some time - it depends to system setup, take a look to discussions
around SO_REUSEPORT for Linux or SO_REUSEADDR and SO_LINGER for BSD.
So from stability point of view it's better to just return random number
between 49152 and 65535.
Well, this doesn't seem to improve the odds by much. When there are more
tests run in parallel, all of them requiring a free port, nothing
prevents the random function to return the same port to all of them.
Also, two subsequent requests can return the same port and cause
problems with timing when a port used by a previous test is not fully
ready to be assigned to a different socket. And as Dmitry pointed out
unless one can keep hold of the allocated socket and use it later there
is no guarantee that a port which was tested unallocated will remain
unallocated also for the next few milliseconds.
The only fail proof solution would be a port allocating service provided
by the harness. Until then we can only (hopefully) decrease the chance
of intermittent failures due to a port being in use.
-JB-
-Dmitry
[1]
141 public static int getFreePort() throws InterruptedException,
IOException {
142 int port = -1;
143
144 while (port <= 0) {
145 Thread.sleep(100);
146
147 ServerSocket serverSocket = null;
148 try {
149 serverSocket = new ServerSocket(0);
150 port = serverSocket.getLocalPort();
151 } finally {
152 serverSocket.close();
153 }
154 }
155
156 return port;
157 }
158
On 2013-11-20 19:40, roger riggs wrote:
Hi,
fyi, The jdk.testlibrary.Utils.getFreePort() method will Open an free
Socket, close it and return
the port number.
And as Alan recommended, use (0) when possible to have the system assign
the port #.
Roger
On 11/20/2013 8:04 AM, Dmitry Samersoff wrote:
Taras,
*The only* correct way to take really free port is:
1. Chose random number between 49152 and 65535
2. Open socket
if socket fails - repeat step 1
if socket OK - return *socket*
If you can't keep the socket open (e.g. you have to pass port number as
property value) you shouldn't do any pre-check as it has no value - as
as soon as you close socket someone can take the port.
So just choose a random number within the range above and let networking
code opening socket to handle port conflict.
-Dmitry
On 2013-11-20 15:54, taras ledkov wrote:
Hi Everyone,
I am working on bug https://bugs.openjdk.java.net/browse/JDK-7195249.
There are two webrevs:
Webrev for jdk part:
http://cr.openjdk.java.net/~anazarov/7195249/jdk/webrev.00/
Webrev for hs part:
http://cr.openjdk.java.net/~anazarov/7195249/hs/webrev.00/
Please take a look at some notes:
- After discussing with Yekaterina Kantserova & Jaroslav Bachorik some
shell tests have been converted to java based tests
- PasswordFilePermissionTest & SSLConfigFilePermissionTest tests looked
very similar, so a common parent class was created for them:
AbstractFilePermissionTest
- What was called RmiRegistrySslTest.java I've renamed to
RmiRegistrySslTestApp.java. The java code to replace old shell script
RmiRegistrySslTest.sh is called RmiRegistrySslTest.java, hence the huge
diff.
- The new RmiRegistrySslTest.java has some lines similar to the
AbstractFilePermissionTest.java, I nevertheless decided to not
complicate the code further and leave it as is. Please let me know if
this is somehow not acceptable
- com/oracle/java/testlibrary/Utils.java that is added to hotspot
repository is taken from this patch:
http://cr.openjdk.java.net/~ykantser/8023138/webrev.00/test/lib/testlibrary/jdk/testlibrary/Utils.java.sdiff.html
- These tests will need additional changes when test library process
tools will support command line options inheritance
(http://mail.openjdk.java.net/pipermail/serviceability-dev/2013-November/013235.html)
