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Add WTSEnumerateProcessesEx and WTS_PROCESS_INFO_EX to Wtsapi32 #981

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@dbwiddis dbwiddis commented Jul 1, 2018

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@FieldOrder({ "SessionId", "ProcessId", "pProcessName", "pUserSid", "NumberOfThreads", "HandleCount",
"PagefileUsage", "PeakPagefileUsage", "WorkingSetSize", "PeakWorkingSetSize", "UserTime", "KernelTime" })
class WTS_PROCESS_INFO_EX extends Structure {
public DWORD SessionId;
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Any reason not to define this as int? Same goes for other DWORDs introduced here.

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Same comment I just noted on another PR. I went back and forth a few times between int and DWORD. What sold me on the latter was reading a message thread about Windows Process IDs, and seeing a comment from a Microsoft Engineer that they actually had seen ProcessID values above Integer.MAX_VALUE. Is there a general policy we follow for JNA mappings? I understand primitives would be more efficient.

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Your argument is sound, see the other PR for my comment on it.

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I'm ok leaving it as is unless/until the JNA project decides to convert ALL the code. As-is, it's somewhat of a mixed bag (I've seen both styles in existing code) and users must generally be responsible. Might be a good subject to put in the Contributing document.

class WTS_PROCESS_INFO_EX extends Structure {
public DWORD SessionId;
public DWORD ProcessId;
public Pointer pProcessName; // Either LPSTR or LPWSTR
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This can be mapped as String, if you specify the correct type mapper - see Sspi#SecPkgInfo for a sample.

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Funny, I originally had (and still have) it as a String in my project, and it worked, but I didn't know the inner workings well enough to know if it handled the Unicode/ANSI conversions. I'll put it back!

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Not sure if you already found the "explanation". If not this is the short version: The default Windows function mapper maps to either the ASCII or the UNICODE version of a function (if they follow the windows conventions) based on the value of the w32.ascii system property. The same logic is then applied in com.sun.jna.win32.W32APITypeMapper.W32APITypeMapper(boolean). A string is on the fly converted to a WString and on the return way converted back to a string.

* the function fails, the return value is zero. To get extended
* error information, call the GetLastError function.
*/
boolean WTSFreeMemoryEx(int WTSTypeClass, Pointer pMemory, long NumberOfEntries);
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This should explode! NumberOfEntries is a ULONG and according to the MSDN that is 32 bit long and not 64bit:
https://docs.microsoft.com/en-us/windows/desktop/winprog/windows-data-types

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Good catch. Interestingly, this was one of my first JNA mappings a few years ago, and I obviously made some errors then, most that I've fixed. But it's been in my project's code and hasn't caused a (known) problem yet. Obviously needs fixing but may be a case where byte boundaries are saving my skin.

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I've been there and was burned by it - searching for something like this for a few hours sharpens sensitivity for this :-)

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