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Java Native Access Platform
/* Copyright (c) 2018 Daniel Widdis, All Rights Reserved
*
* The contents of this file is dual-licensed under 2
* alternative Open Source/Free licenses: LGPL 2.1 or later and
* Apache License 2.0. (starting with JNA version 4.0.0).
*
* You can freely decide which license you want to apply to
* the project.
*
* You may obtain a copy of the LGPL License at:
*
* http://www.gnu.org/licenses/licenses.html
*
* A copy is also included in the downloadable source code package
* containing JNA, in file "LGPL2.1".
*
* You may obtain a copy of the Apache License at:
*
* http://www.apache.org/licenses/
*
* A copy is also included in the downloadable source code package
* containing JNA, in file "AL2.0".
*/
package com.sun.jna.platform.win32;
import java.util.ArrayList;
import java.util.List;
import com.sun.jna.Memory;
import com.sun.jna.Native;
import com.sun.jna.platform.win32.WinDef.DWORD;
import com.sun.jna.platform.win32.WinDef.DWORDByReference;
import java.util.Collections;
/**
* Pdh utility API.
*
* @author widdis[at]gmail[dot]com
*/
public abstract class PdhUtil {
private static final int CHAR_TO_BYTES = Boolean.getBoolean("w32.ascii") ? 1 : Native.WCHAR_SIZE;
// This REG_MULTI_SZ value in HKLM provides English counters regardless of
// the current locale setting
private static final String ENGLISH_COUNTER_KEY = "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Perflib\\009";
private static final String ENGLISH_COUNTER_VALUE = "Counter";
/**
* Utility method to call Pdh's PdhLookupPerfNameByIndex that allocates the
* required memory for the szNameBuffer parameter based on the type mapping
* used, calls to PdhLookupPerfNameByIndex, and returns the received string.
*
* @param szMachineName
* Null-terminated string that specifies the name of the computer
* where the specified performance object or counter is located.
* The computer name can be specified by the DNS name or the IP
* address. If NULL, the function uses the local computer.
* @param dwNameIndex
* Index of the performance object or counter.
* @return Returns the name of the performance object or counter.
*/
public static String PdhLookupPerfNameByIndex(String szMachineName, int dwNameIndex) {
// Call once to get required buffer size
DWORDByReference pcchNameBufferSize = new DWORDByReference(new DWORD(0));
int result = Pdh.INSTANCE.PdhLookupPerfNameByIndex(szMachineName, dwNameIndex, null, pcchNameBufferSize);
if(result != WinError.ERROR_SUCCESS && result != Pdh.PDH_MORE_DATA) {
throw new PdhException(result);
}
// Can't allocate 0 memory
if (pcchNameBufferSize.getValue().intValue() < 1) {
return "";
}
// Allocate buffer and call again
Memory mem = new Memory(pcchNameBufferSize.getValue().intValue() * CHAR_TO_BYTES);
result = Pdh.INSTANCE.PdhLookupPerfNameByIndex(szMachineName, dwNameIndex, mem, pcchNameBufferSize);
if(result != WinError.ERROR_SUCCESS) {
throw new PdhException(result);
}
// Convert buffer to Java String
if (CHAR_TO_BYTES == 1) {
return mem.getString(0);
} else {
return mem.getWideString(0);
}
}
/**
* Utility method similar to Pdh's PdhLookupPerfIndexByName that returns the
* counter index corresponding to the specified counter name in English.
* Uses the registry on the local machine to find the index in the English
* locale, regardless of the current language setting on the machine.
*
* @param szNameBuffer
* The English name of the performance counter
* @return The counter's index if it exists, or 0 otherwise.
*/
public static int PdhLookupPerfIndexByEnglishName(String szNameBuffer) {
// Look up list of english names and ids
String[] counters = Advapi32Util.registryGetStringArray(WinReg.HKEY_LOCAL_MACHINE, ENGLISH_COUNTER_KEY,
ENGLISH_COUNTER_VALUE);
// Array contains alternating index/name pairs
// {"1", "1847", "2", "System", "4", "Memory", ... }
// Get position of name in the array (odd index), return parsed value of
// previous even index
for (int i = 1; i < counters.length; i += 2) {
if (counters[i].equals(szNameBuffer)) {
try {
return Integer.parseInt(counters[i - 1]);
} catch (NumberFormatException e) {
// Unexpected but handle anyway
return 0;
}
}
}
// Didn't find the String
return 0;
}
/**
* Utility method to call Pdh's PdhEnumObjectItems that allocates the
* required memory for the lists parameters based on the type mapping used,
* calls to PdhEnumObjectItems, and returns the received lists of strings.
*
* @param szDataSource
* String that specifies the name of the log file used to
* enumerate the counter and instance names. If NULL, the
* function uses the computer specified in the szMachineName
* parameter to enumerate the names.
* @param szMachineName
* String that specifies the name of the computer that contains
* the counter and instance names that you want to enumerate.
* Include the leading slashes in the computer name, for example,
* \\computername. If the szDataSource parameter is NULL, you can
* set szMachineName to NULL to specify the local computer.
* @param szObjectName
* String that specifies the name of the object whose counter and
* instance names you want to enumerate.
* @param dwDetailLevel
* Detail level of the performance items to return. All items
* that are of the specified detail level or less will be
* returned.
* @return Returns a List of Strings of the counters for the object.
*/
public static PdhEnumObjectItems PdhEnumObjectItems(String szDataSource, String szMachineName, String szObjectName,
int dwDetailLevel) {
List counters = new ArrayList();
List instances = new ArrayList();
// Call once to get string lengths
DWORDByReference pcchCounterListLength = new DWORDByReference(new DWORD(0));
DWORDByReference pcchInstanceListLength = new DWORDByReference(new DWORD(0));
int result = Pdh.INSTANCE.PdhEnumObjectItems(szDataSource, szMachineName, szObjectName, null, pcchCounterListLength, null,
pcchInstanceListLength, dwDetailLevel, 0);
if(result != WinError.ERROR_SUCCESS && result != Pdh.PDH_MORE_DATA) {
throw new PdhException(result);
}
Memory mszCounterList = null;
Memory mszInstanceList = null;
if (pcchCounterListLength.getValue().intValue() > 0) {
mszCounterList = new Memory(pcchCounterListLength.getValue().intValue() * CHAR_TO_BYTES);
}
if (pcchInstanceListLength.getValue().intValue() > 0) {
mszInstanceList = new Memory(pcchInstanceListLength.getValue().intValue() * CHAR_TO_BYTES);
}
result = Pdh.INSTANCE.PdhEnumObjectItems(szDataSource, szMachineName, szObjectName, mszCounterList,
pcchCounterListLength, mszInstanceList, pcchInstanceListLength, dwDetailLevel, 0);
if(result != WinError.ERROR_SUCCESS) {
throw new PdhException(result);
}
// Fetch counters
if (mszCounterList != null) {
int offset = 0;
while (offset < mszCounterList.size()) {
String s = null;
if (CHAR_TO_BYTES == 1) {
s = mszCounterList.getString(offset);
} else {
s = mszCounterList.getWideString(offset);
}
// list ends with double null
if (s.isEmpty()) {
break;
}
counters.add(s);
// Increment for string + null terminator
offset += (s.length() + 1) * CHAR_TO_BYTES;
}
}
if(mszInstanceList != null) {
int offset = 0;
while (offset < mszInstanceList.size()) {
String s = null;
if (CHAR_TO_BYTES == 1) {
s = mszInstanceList.getString(offset);
} else {
s = mszInstanceList.getWideString(offset);
}
// list ends with double null
if (s.isEmpty()) {
break;
}
instances.add(s);
// Increment for string + null terminator
offset += (s.length() + 1) * CHAR_TO_BYTES;
}
}
return new PdhEnumObjectItems(counters, instances);
}
/**
* Holder Object for PdhEnumObjectsItems. The embedded lists are modifiable
* lists and can be accessed through the {@link #getCounters()} and
* {@link #getInstances()} accessors.
*/
public static class PdhEnumObjectItems {
private final List counters;
private final List instances;
public PdhEnumObjectItems(List counters, List instances) {
this.counters = copyAndEmptyListForNullList(counters);
this.instances = copyAndEmptyListForNullList(instances);
}
/**
* @return the embedded counters list, all calls to this function receive
* the same list and thus share modifications
*/
public List getCounters() {
return counters;
}
/**
* @return the embedded instances list, all calls to this function receive
* the same list and thus share modifications
*/
public List getInstances() {
return instances;
}
private List copyAndEmptyListForNullList (List inputList) {
if(inputList == null) {
return new ArrayList();
} else {
return new ArrayList(inputList);
}
}
@Override
public String toString() {
return "PdhEnumObjectItems{" + "counters=" + counters + ", instances=" + instances + '}';
}
}
public static final class PdhException extends RuntimeException {
private final int errorCode;
public PdhException(int errorCode) {
super(String.format("Pdh call failed with error code 0x%08X", errorCode));
this.errorCode = errorCode;
}
public int getErrorCode() {
return errorCode;
}
}
}