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fix(worker): narrow AlarmAckWriter ArgumentException interop filter

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Resolve the operator user, password and comment before the interop try
blocks, and match ArgumentException as an MXAccess failure only when it
carries E_INVALIDARG and is not ArgumentNullException or
ArgumentOutOfRangeException. A programming error inside the try blocks
now propagates instead of being reported as an authentication or write
failure.

Fixes #164

Claude-Session: https://claude.ai/code/session_016J6isfcgqy4SB2RK3ZvFvT
This commit is contained in:
Joseph Doherty
2026-10-20 07:09:02 -04:00
parent 3e988ede88
commit 219611c821
3 changed files with 105 additions and 7 deletions
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src/ZB.MOM.WW.MxGateway.Worker/MxAccess/AlarmAckWriter.cs
+30 -6
View File
@@ -34,6 +34,9 @@ public sealed class AlarmAckWriter : IAlarmAckWriter
/// </summary>
public const int DefaultMaxCachedItems = 256;
/// <summary>E_INVALIDARG, which the interop raises as ArgumentException.</summary>
private const int EInvalidArg = unchecked((int)0x80070057);
private readonly IMxAccessComObjectFactory? factory;
private readonly MxAccessWriteCompletionCache completionCache;
private readonly Action pumpStep;
@@ -104,12 +107,20 @@ public sealed class AlarmAckWriter : IAlarmAckWriter
if (string.IsNullOrWhiteSpace(itemAddress)) throw new ArgumentException("Ack item address is required.", nameof(itemAddress));
if (ackOperator is null) throw new ArgumentNullException(nameof(ackOperator));
// Resolve every argument before the interop try blocks: their catch
// filters accept E_INVALIDARG ArgumentExceptions as MXAccess failures, so
// an argument error raised by this code must fail before reaching them.
if (ackOperator.UserName is null) throw new ArgumentException("Operator user name is required.", nameof(ackOperator));
string verifyUser = ackOperator.VerifyUser;
string password = ackOperator.Password ?? string.Empty;
string commentValue = comment ?? string.Empty;
IMxAccessServer mx = EnsureRegistered();
int userId;
try
{
userId = mx.AuthenticateUser(serverHandle, ackOperator.VerifyUser, ackOperator.Password ?? string.Empty);
userId = mx.AuthenticateUser(serverHandle, verifyUser, password);
}
catch (Exception ex) when (IsInteropFailure(ex))
{
@@ -130,7 +141,7 @@ public sealed class AlarmAckWriter : IAlarmAckWriter
return AlarmAckResult.Create(
AlarmAckOutcome.AuthenticationFailed,
ex.HResult,
$"Operator authentication failed for '{ackOperator.VerifyUser}' (HRESULT 0x{ex.HResult:X8}).");
$"Operator authentication failed for '{verifyUser}' (HRESULT 0x{ex.HResult:X8}).");
}
if (userId == 0)
@@ -138,7 +149,7 @@ public sealed class AlarmAckWriter : IAlarmAckWriter
return AlarmAckResult.Create(
AlarmAckOutcome.AuthenticationFailed,
-1,
$"Operator authentication failed for '{ackOperator.VerifyUser}' (no user id returned).");
$"Operator authentication failed for '{verifyUser}' (no user id returned).");
}
ulong baselineVersion = 0;
@@ -177,7 +188,7 @@ public sealed class AlarmAckWriter : IAlarmAckWriter
pumpStep();
step = "Write";
baselineVersion = completionCache.CurrentVersion(serverHandle, itemHandle);
mx.Write(serverHandle, itemHandle, comment ?? string.Empty, userId);
mx.Write(serverHandle, itemHandle, commentValue, userId);
}
catch (Exception ex) when (IsInteropFailure(ex))
{
@@ -249,10 +260,23 @@ public sealed class AlarmAckWriter : IAlarmAckWriter
/// ArgumentException, E_ACCESSDENIED to UnauthorizedAccessException) and
/// the rest to COMException. Each carries the HRESULT in Exception.HResult.
/// </summary>
/// <remarks>
/// The ArgumentException arm exists because a wrong password or unknown
/// user makes <c>AuthenticateUser</c> throw ArgumentException with
/// E_INVALIDARG (0x80070057), observed live on windev on 2026-10-19. It
/// is narrowed to that HRESULT, and excludes ArgumentNullException and
/// ArgumentOutOfRangeException, so a programming error inside the try
/// blocks propagates as a bug instead of being reported as an MXAccess
/// authentication or write failure. The interop never raises those two
/// subtypes for a COM HRESULT.
/// </remarks>
private static bool IsInteropFailure(Exception ex) =>
ex is ExternalException
|| ex is ArgumentException
|| ex is UnauthorizedAccessException;
|| ex is UnauthorizedAccessException
|| (ex is ArgumentException
&& ex is not ArgumentNullException
&& ex is not ArgumentOutOfRangeException
&& ex.HResult == EInvalidArg);
private static bool IsServerGone(int hresult) =>
hresult == unchecked((int)0x80010108) // RPC_E_DISCONNECTED