RFR [9] 8058216: NetworkInterface.getHardwareAddress can return zero length byte array when run with preferIPv4Stack

[Michael McMahon]

Looks fine to me

Michael

On 12/09/14 10:05, Chris Hegarty wrote:
>
> On 11/09/14 14:42, Chris Hegarty wrote:
>> A small issue was found when running JCK tests on modern Windows 
>> platforms, that have IPv6 enabled, but forced to run with the IPv4 
>> Stack, -Djava.net.preferIPv4Stack=true. 
>> NetworkInterface.getHardwareAddress() can return a zero length byte 
>> array, where is should, and is specified to, return null.
>>
>> The solution is to only create the byte array if the physical address 
>> is known. Running an existing regression test with 
>> -Djava.net.preferIPv4Stack=true covers this issue.
>
> As was pointed out to me off list, the test should include this bug Id 
> too. It is now added, and some more context around the diffs, for 
> easier review.
>
> ---
> diff --git a/src/java.base/windows/native/libnet/NetworkInterface.c 
> b/src/java.base/windows/native/libnet/NetworkInterface.c
> --- a/src/java.base/windows/native/libnet/NetworkInterface.c
> +++ b/src/java.base/windows/native/libnet/NetworkInterface.c
> @@ -975,39 +975,41 @@
>  JNIEXPORT jbyteArray JNICALL Java_java_net_NetworkInterface_getMacAddr0
>      (JNIEnv *env, jclass class, jbyteArray addrArray, jstring name, 
> jint index) {
>    jbyteArray ret = NULL;
>    int len;
>    MIB_IFROW *ifRowP;
>
>    // Retained for now to support IPv4 only stack, 
> java.net.preferIPv4Stack
>    if (ipv6_available()) {
>      return Java_java_net_NetworkInterface_getMacAddr0_XP(env, class, 
> name, index);
>    } else {
>      ifRowP = getIF(index);
>      if (ifRowP != NULL) {
>        switch(ifRowP->dwType) {
>        case MIB_IF_TYPE_ETHERNET:
>        case MIB_IF_TYPE_TOKENRING:
>        case MIB_IF_TYPE_FDDI:
>        case IF_TYPE_IEEE80211:
>          len = ifRowP->dwPhysAddrLen;
> -        ret = (*env)->NewByteArray(env, len);
> -        if (!IS_NULL(ret)) {
> -          (*env)->SetByteArrayRegion(env, ret, 0, len, (jbyte *) 
> ifRowP->bPhysAddr);
> +        if (len > 0) {
> +            ret = (*env)->NewByteArray(env, len);
> +            if (!IS_NULL(ret)) {
> +              (*env)->SetByteArrayRegion(env, ret, 0, len, (jbyte *) 
> ifRowP->bPhysAddr);
> +            }
>          }
>          break;
>        }
>        free(ifRowP);
>      }
>      return ret;
>    }
>  }
>
> $ hg diff test/java/net/NetworkInterface/Test.javadiff --git 
> a/test/java/net/NetworkInterface/Test.java 
> b/test/java/net/NetworkInterface/Test.java
> --- a/test/java/net/NetworkInterface/Test.java
> +++ b/test/java/net/NetworkInterface/Test.java
> @@ -22,7 +22,9 @@
>   */
>
>  /* @test
> - * @bug 4405354 6594296
> + * @bug 4405354 6594296 8058216
> + * @run main Test
> + * @run main/othervm -Djava.net.preferIPv4Stack=true Test
>   * @summary Basic tests for NetworkInterface
>   */
>  import java.net.NetworkInterface;
>
> -Chris.