RFR 8156709: Cannot call setSeed on NativePRNG on Mac if EGD is /dev/urandom

[Wang Weijun]

Hi All

Please review the fix at

  http://cr.openjdk.java.net/~weijun/8156709/webrev.00/

On *nix, we open EGD and write into it when setSeed() is called. We were aware of the device not openable and have been ignoring it (Note we still write to a mix random). Now it seems on a Mac is can be opened for write but not writable.

See this jshell output, the exception is thrown on write().

-> new FileOutputStream("/dev/urandom").write(12)
|  java.io.IOException thrown: Operation not permitted
|        at FileOutputStream.write (Native Method)
|        at FileOutputStream.write (FileOutputStream.java:291)
|        at (#17:1)

Thanks
Max