Convert SAFEARRAYByReference to something else

crazy ghost pseudo555

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Dec 26, 2024, 7:30:15 AM12/26/24

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Hello everyone,

I'm playing with JNA, to do some requests on Win32_NetworkAdapterConfiguration class.

I manage to get some results, but few properties are "null" when same call using vbscript returns proper values.

The properties i'm interested here are : IPAddress, IPSubne & DefaultIPGateway.
Using jna, they all are null, because their variant type is 8200 (which is VT_ARRAY & VT_BSTR) and WbemcliUtil.enumerateProperties() falls in the default case (around line 355 for the 5.5.0 version).

Using debuger, i find out the object is a SAFEARRAY.ByReference

As it's a safearray, i try to get each element using getElement() method.

It fails again, this time because the VarType (which is 116) is not handled.

Anyone has a idea how to get the proper value for thoses properties ?

Matthias Bläsing

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Dec 26, 2024, 1:35:32 PM12/26/24

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Hi

please provide a _minimal runnable_ sample of what you tried.

Greetings

Matthias

Am Donnerstag, dem 26.12.2024 um 04:30 -0800 schrieb crazy ghost
pseudo555:

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crazy ghost pseudo555

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Dec 27, 2024, 5:40:19 AM12/27/24

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Hello,

Originally, I based my code over oshi-core implementation.

public enum NetworkAdapterConfigurationProperty {
InterfaceIndex,
IPAddress;
}

/* package for test */ Void wmiCmd2() {
final WmiQueryHandler instance = WmiQueryHandler.createInstance(); // src: https://github.com/oshi/oshi/blob/master/oshi-core/src/main/java/oshi/util/platform/windows/WmiQueryHandler.java
if (instance != null) {
final WmiQuery<NetworkAdapterConfigurationProperty> nacConfQuery = new WmiQuery<>( "Win32_NetworkAdapterConfiguration" , NetworkAdapterConfigurationProperty.class);
final WmiResult<NetworkAdapterConfigurationProperty> nacConfRes = instance.queryWMI(nacConfQuery);
for (int i = 0; i < nacConfRes.getResultCount(); i++) {
final Object key = nacConfRes.getValue(NetworkAdapterConfigurationProperty.InterfaceIndex, i);
Object ip = nacConfRes.getValue(NetworkAdapterConfigurationProperty.IPAddress, i);
if (ip == null) {
System.err.println("CIMTYPE is : " + nacConfRes.getCIMType(NetworkAdapterConfigurationProperty.IPAddress));
System.err.println(" VtType is : " + nacConfRes.getVtType(NetworkAdapterConfigurationProperty.IPAddress));
} else if (ip instanceof SAFEARRAY) {
final SAFEARRAY arr = (SAFEARRAY) ip;
if (arr != null) {
System.err.println("dim: " + arr.getDimensionCount());
System.err.println("elm : " + arr.getElemsize());
System.err.println("vt : " + arr.getVarType());
System.err.println("from " + arr.getLBound(0) + " to " + arr.getUBound(0));
for (int ii = arr.getLBound(0); ii <= arr.getUBound(0); ii++) {
System.out.println("\t" + arr.getElement(ii));
}
}
} else {
System.err.println(" IP : " + ip.getClass());
}
System.err.println("+++++++++++++++++++++++");
}
}
return null;
}

Which provide this result :

Deal with Key #20
CIMTYPE is : 8200
VtType is : 8200
+++++++++++++++++++++++
Deal with Key #8
CIMTYPE is : 8200
VtType is : 8200
+++++++++++++++++++++++
Deal with Key #5
CIMTYPE is : 8200
VtType is : 8200
+++++++++++++++++++++++

So i edit WbemcliUtil WmiResult<T> enumerateProperties(IEnumWbemClassObject enumerator, Class<T> propertyEnum, int timeout) to add the following case:
case 8200:
values.add(vtType, cimType, property, pVal.getValue());
break;

doing so, the output changed, as ip is no longer null, but a SAFEARRAY:

Deal with Key #20
CIMTYPE is : 8200
VtType is : 8200
+++++++++++++++++++++++
Deal with Key #8
dim: 1
elm : 4
vt : 8
from 0 to 3
Exception in thread "main" com.sun.jna.platform.win32.COM.COMException: Paramètre incorrect.(HRESULT: 80070057)
at com.sun.jna.platform.win32.COM.COMUtils.checkRC(COMUtils.java:117)
at com.sun.jna.platform.win32.OaIdl$SAFEARRAY.getElement(OaIdl.java:821)
at fr.def.iss.ssiutils.network.adapters.WindowsNetworkAdapterConfTest.wmiCmd2(WindowsNetworkAdapterConfTest.java:135)
at fr.def.iss.ssiutils.network.adapters.WindowsNetworkAdapterConfTest.main(WindowsNetworkAdapterConfTest.java:34)

So I gave up there.

Doing some research, i found out this reported issue was almost what i'm looking for: https://github.com/java-native-access/jna/issues/1083

I adapt the code to use the expected "Win32_NetworkAdapterConfiguration" instead.

Which game me this code:

private static void pouet() throws Exception {
Ole32.INSTANCE.CoInitializeEx(null, Ole32.COINIT_MULTITHREADED);
// Connect to the server
Wbemcli.IWbemServices svc = WbemcliUtil.connectServer("ROOT\\CIMV2");
// Send query
try {
Wbemcli.IEnumWbemClassObject enumerator = svc.ExecQuery("WQL", "SELECT InterfaceIndex, IPAddress FROM Win32_NetworkAdapterConfiguration",
Wbemcli.WBEM_FLAG_FORWARD_ONLY | Wbemcli.WBEM_FLAG_RETURN_IMMEDIATELY, null);
try {
IWbemClassObject[] result;
VARIANT.ByReference pVal = new VARIANT.ByReference();
IntByReference pType = new IntByReference();
IntByReference plFlavor = new IntByReference();
while(true) {
result = enumerator.Next(0, 1);
if(result.length == 0) {
break;
}
COMUtils.checkRC(result[0].Get("InterfaceIndex", 0, pVal, pType, plFlavor));
System.out.println("---------" + pVal.getValue() + "-------------");
OleAuto.INSTANCE.VariantClear(pVal);
COMUtils.checkRC(result[0].Get("IPAddress", 0, pVal, pType, plFlavor));
SAFEARRAY safeArray = (SAFEARRAY) pVal.getValue();
if(safeArray != null) {
for(int i = safeArray.getLBound(0); i<=safeArray.getUBound(0); i++) {
System.out.println("\t" + safeArray.getElement(i));
}
}
OleAuto.INSTANCE.VariantClear(pVal);
result[0].Release();
}
} finally {
// Cleanup
enumerator.Release();
}
} finally {
// Cleanup
svc.Release();
}
}

Which doesn't work well either. By that I mean running it produces no result at all.
So i add some syserr / catchblock here and there :

private static void pouet() throws Exception {
Ole32.INSTANCE.CoInitializeEx(null, Ole32.COINIT_MULTITHREADED);
// Connect to the server
Wbemcli.IWbemServices svc = WbemcliUtil.connectServer("ROOT\\CIMV2");
// Send query
try {
Wbemcli.IEnumWbemClassObject enumerator = svc.ExecQuery("WQL", "SELECT InterfaceIndex, IPAddress, IPSubnet FROM Win32_NetworkAdapterConfiguration",
Wbemcli.WBEM_FLAG_FORWARD_ONLY | Wbemcli.WBEM_FLAG_RETURN_IMMEDIATELY, null);
try {
IWbemClassObject[] result;
VARIANT.ByReference pVal = new VARIANT.ByReference();
IntByReference pType = new IntByReference();
IntByReference plFlavor = new IntByReference();
while(true) {
result = enumerator.Next(0, 1);
if(result.length == 0) {
System.err.println("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! break");
break;
}
COMUtils.checkRC(result[0].Get("InterfaceIndex", 0, pVal, pType, plFlavor));
System.out.println("---------" + pVal.getValue() + "-------------");
OleAuto.INSTANCE.VariantClear(pVal);
COMUtils.checkRC(result[0].Get("IPAddress", 0, pVal, pType, plFlavor));
SAFEARRAY safeArray = (SAFEARRAY) pVal.getValue();
if(safeArray != null) {
for(int i = safeArray.getLBound(0); i<=safeArray.getUBound(0); i++) {
System.out.println("\t" + safeArray.getElement(i));
}
}
OleAuto.INSTANCE.VariantClear(pVal);
result[0].Release();
}
} catch (Throwable e) {
e.printStackTrace();
} finally {
// Cleanup
enumerator.Release();
System.err.println("finaly2");
}
} catch (Throwable e1) {
e1.printStackTrace();
} finally {
// Cleanup
svc.Release();
System.err.println("finaly1");
}
}

And still using debugger (a breakpoint on the "Wbemcli.IEnumWbemClassObject enumerator" the going line per line), i get some answers :

---------20-------------
---------8-------------
192.168.1.39
fe80::a150:9e1:f91d:3ea0
2001:861:3840:1c90:dd15:c68:82f2:a947
2001:861:3840:1c90:50e5:9470:5c72:93ad
java.lang.Error: Invalid memory access
at com.sun.jna.Native.getShort(Native Method)
at com.sun.jna.Pointer.getShort(Pointer.java:568)
at com.sun.jna.Pointer.getValue(Pointer.java:378)
at com.sun.jna.Structure.readField(Structure.java:732)
at com.sun.jna.Structure.read(Structure.java:591)
at com.sun.jna.platform.win32.OaIdl$SAFEARRAY.read(OaIdl.java:586)
at com.sun.jna.Structure.autoRead(Structure.java:2203)
at com.sun.jna.Structure.conditionalAutoRead(Structure.java:561)
at com.sun.jna.Structure.updateStructureByReference(Structure.java:690)
at com.sun.jna.Pointer.getValue(Pointer.java:367)
at com.sun.jna.Structure.readField(Structure.java:732)
at com.sun.jna.Union.readField(Union.java:223)
at com.sun.jna.Structure.read(Structure.java:591)
at com.sun.jna.Pointer.getValue(Pointer.java:370)
at com.sun.jna.Structure.readField(Structure.java:732)
at com.sun.jna.Structure.read(Structure.java:591)
at com.sun.jna.Pointer.getValue(Pointer.java:370)
at com.sun.jna.Structure.readField(Structure.java:732)
at com.sun.jna.Union.readField(Union.java:223)
at com.sun.jna.Structure.read(Structure.java:591)
at com.sun.jna.Structure.autoRead(Structure.java:2203)
at com.sun.jna.Function.invoke(Function.java:381)
at com.sun.jna.Function.invoke(Function.java:315)
at com.sun.jna.Function.invoke(Function.java:306)
at com.sun.jna.platform.win32.COM.COMInvoker._invokeNativeObject(COMInvoker.java:48)
at com.sun.jna.platform.win32.COM.Wbemcli$IWbemClassObject.Get(Wbemcli.java:120)
at com.sun.jna.platform.win32.COM.Wbemcli$IWbemClassObject.Get(Wbemcli.java:126)
at fr.def.iss.ssiutils.network.adapters.WindowsNetworkAdapterConfTest.pouet(WindowsNetworkAdapterConfTest.java:60)
at fr.def.iss.ssiutils.network.adapters.WindowsNetworkAdapterConfTest.main(WindowsNetworkAdapterConfTest.java:31)

Note:

* IPAddress values displayed are the expected one (none for 20, four different results for interfaceIndex 8).

* exception occured when going to the next result (interfaceIndex 5 in my case)

If i comment this block :

COMUtils.checkRC(result[0].Get("IPAddress", 0, pVal, pType, plFlavor));
SAFEARRAY safeArray = (SAFEARRAY) pVal.getValue();
if(safeArray != null) {
for(int i = safeArray.getLBound(0); i<=safeArray.getUBound(0); i++) {
System.out.println("\t" + safeArray.getElement(i));
}
}
OleAuto.INSTANCE.VariantClear(pVal);

The error doesn't appear (still using breakpoint, otherwise no result):

---------20-------------
---------8-------------
---------5-------------
---------13-------------
[...]

I manage to solve the java.lang.Error: Invalid memory access by moving

IWbemClassObject[] result;
VARIANT.ByReference pVal = new VARIANT.ByReference();
IntByReference pType = new IntByReference();
IntByReference plFlavor = new IntByReference();

Inside the while loop.

To sum up :

* I still don't get why the "running way" doesn't work. Why should i have to use a breakpoint on "Wbemcli.IEnumWbemClassObject enumerator" then go step by step ?

* I don't understand why oshi-core implementation doesn't work, as the minimal case provided for issue #1083 "works".

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Message has been deleted

Daniel B. Widdis

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Dec 27, 2024, 1:39:57 PM12/27/24

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Why are you clearing pVal before reading it?

OleAuto.INSTANCE.VariantClear(pVal);
COMUtils.checkRC(result[0].Get("IPAddress", 0, pVal, pType, plFlavor));
SAFEARRAY safeArray = (SAFEARRAY) pVal.getValue();

To view this discussion visit https://groups.google.com/d/msgid/jna-users/CABRSi9oiWpz4yUW_oQ10NWd4QVKKx3rw83tN7UddLmkWPrM1HQ%40mail.gmail.com.

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Dan Widdis

crazy ghost pseudo555

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Dec 30, 2024, 5:59:24 AM12/30/24

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I don't ?

For me the following code:

COMUtils.checkRC(result[0].Get("InterfaceIndex", 0, pVal, pType, plFlavor));
System.out.println("---------" + pVal.getValue() + "-------------");
OleAuto.INSTANCE.VariantClear(pVal);
COMUtils.checkRC(result[0].Get("IPAddress", 0, pVal, pType, plFlavor));
SAFEARRAY safeArray = (SAFEARRAY) pVal.getValue();
if(safeArray != null) {
for(int i = safeArray.getLBound(0); i<=safeArray.getUBound(0); i++) {
System.out.println("\t" + safeArray.getElement(i));
}
}
OleAuto.INSTANCE.VariantClear(pVal);
result[0].Release();

can be splitted that way :

COMUtils.checkRC(result[0].Get("InterfaceIndex", 0, pVal, pType, plFlavor));
System.out.println("---------" + pVal.getValue() + "-------------");
OleAuto.INSTANCE.VariantClear(pVal);

COMUtils.checkRC(result[0].Get("IPAddress", 0, pVal, pType, plFlavor));
SAFEARRAY safeArray = (SAFEARRAY) pVal.getValue();
if(safeArray != null) {
for(int i = safeArray.getLBound(0); i<=safeArray.getUBound(0); i++) {
System.out.println("\t" + safeArray.getElement(i));
}
}
OleAuto.INSTANCE.VariantClear(pVal);

result[0].Release();

So, for me, the first call to VariantClear clears the InterfaceIndex, not the IPAddress part.

And the error occured when going to next iterator value (i mean first result = enumerator.Next(0, 1); is complete, it's the next time this is called that the issue occured.

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Daniel B. Widdis

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Dec 30, 2024, 12:11:31 PM12/30/24

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My apologies. Probably lack of coffee.

As the author of the oshi-core code, I fully admit it may have a bug; I did my best to port example C source from MS docs.

To view this discussion visit https://groups.google.com/d/msgid/jna-users/CABRSi9r0BpB76ZoCU7JC4F%3DcLbf%2BubBOq9n1cmA1apebieRx-g%40mail.gmail.com.

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Dan Widdis

crazy ghost pseudo555

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Dec 30, 2024, 1:19:57 PM12/30/24

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No worries, I could have missed something as well ;)

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crazy ghost pseudo555

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Dec 30, 2024, 3:46:43 PM12/30/24

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I think, i find out why the running way doesn't work.

It's due to 0 as timeout in this line: result = enumerator.Next(-0 1);

Changing 0 by -1 make it work as expected.

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