Sanity check ShPk mods, ban incompatible ones

Author: Exter-N

Penumbra/Interop/Processing/ShpkPathPreProcessor.cs

@@ -0,0 +1,85 @@
+using FFXIVClientStructs.FFXIV.Client.System.Resource;
+using Penumbra.Api.Enums;
+using Penumbra.Collections;
+using Penumbra.GameData.Files;
+using Penumbra.GameData.Files.Utility;
+using Penumbra.Interop.Hooks.ResourceLoading;
+using Penumbra.String;
+using Penumbra.String.Classes;
+using Penumbra.UI;
+
+namespace Penumbra.Interop.Processing;
+
+/// <summary>
+/// Path pre-processor for shader packages that reverts redirects to known invalid files, as bad ShPks can crash the game.
+/// </summary>
+public sealed class ShpkPathPreProcessor(ResourceManagerService resourceManager, ChatWarningService chatWarningService) : IPathPreProcessor
+{
+    public ResourceType Type
+        => ResourceType.Shpk;
+
+    public unsafe FullPath? PreProcess(ResolveData resolveData, CiByteString path, Utf8GamePath originalGamePath, bool nonDefault, FullPath? resolved)
+    {
+        chatWarningService.CleanLastFileWarnings(false);
+
+        if (!resolved.HasValue)
+            return null;
+
+        // Skip the sanity check for game files. We are not considering the case where the user has modified game file: it's at their own risk.
+        var resolvedPath = resolved.Value;
+        if (!resolvedPath.IsRooted)
+            return resolvedPath;
+
+        // If the ShPk is already loaded, it means that it already passed the sanity check.
+        var existingResource = resourceManager.FindResource(ResourceCategory.Shader, ResourceType.Shpk, unchecked((uint)resolvedPath.InternalName.Crc32));
+        if (existingResource != null)
+            return resolvedPath;
+
+        var checkResult = SanityCheck(resolvedPath.FullName);
+        if (checkResult == SanityCheckResult.Success)
+            return resolvedPath;
+
+        Penumbra.Log.Warning($"Refusing to honor file redirection because of failed sanity check (result: {checkResult}). Original path: {originalGamePath} Redirected path: {resolvedPath}");
+        chatWarningService.PrintFileWarning(resolvedPath.FullName, originalGamePath, WarningMessageComplement(checkResult));
+
+        return null;
+    }
+
+    private static SanityCheckResult SanityCheck(string path)
+    {
+        try
+        {
+            using var file = MmioMemoryManager.CreateFromFile(path);
+            var bytes = file.GetSpan();
+
+            return ShpkFile.FastIsLegacy(bytes)
+                ? SanityCheckResult.Legacy
+                : SanityCheckResult.Success;
+        }
+        catch (FileNotFoundException)
+        {
+            return SanityCheckResult.NotFound;
+        }
+        catch (IOException)
+        {
+            return SanityCheckResult.IoError;
+        }
+    }
+
+    private static string WarningMessageComplement(SanityCheckResult result)
+        => result switch
+        {
+            SanityCheckResult.IoError  => "cannot read the modded file.",
+            SanityCheckResult.NotFound => "the modded file does not exist.",
+            SanityCheckResult.Legacy   => "this mod is not compatible with Dawntrail. Get an updated version, if possible, or disable it.",
+            _                          => string.Empty,
+        };
+
+    private enum SanityCheckResult
+    {
+        Success,
+        IoError,
+        NotFound,
+        Legacy,
+    }
+}

Penumbra/Mods/Manager/ModManager.cs

@@ -350,4 +350,22 @@ private void ScanMods()
             Penumbra.Log.Error($"Could not scan for mods:\n{ex}");
         }
     }
+
+    public bool TryIdentifyPath(string path, [NotNullWhen(true)] out Mod? mod, [NotNullWhen(true)] out string? relativePath)
+    {
+        var relPath = Path.GetRelativePath(BasePath.FullName, path);
+        if (relPath != "." && (relPath.StartsWith('.') || Path.IsPathRooted(relPath)))
+        {
+            mod          = null;
+            relativePath = null;
+            return false;
+        }
+
+        var modDirectorySeparator = relPath.IndexOfAny([Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar]);
+
+        var modDirectory = modDirectorySeparator < 0 ? relPath : relPath[..modDirectorySeparator];
+        relativePath = modDirectorySeparator < 0 ? string.Empty : relPath[(modDirectorySeparator + 1)..];
+
+        return TryGetMod(modDirectory, "\0", out mod);
+    }
 }

Penumbra/UI/ChatWarningService.cs

@@ -0,0 +1,56 @@
+using Dalamud.Plugin.Services;
+using OtterGui.Services;
+using Penumbra.Mods.Manager;
+using Penumbra.String.Classes;
+
+namespace Penumbra.UI;
+
+public sealed class ChatWarningService(IChatGui chatGui, IClientState clientState, ModManager modManager) : IUiService
+{
+    private readonly Dictionary<string, (DateTime, string)> _lastFileWarnings = [];
+    private          int                                    _lastFileWarningsCleanCounter;
+
+    private const           int      LastFileWarningsCleanCycle = 100;
+    private static readonly TimeSpan LastFileWarningsMaxAge     = new(1, 0, 0);
+
+    public void CleanLastFileWarnings(bool force)
+    {
+        if (!force)
+        {
+            _lastFileWarningsCleanCounter = (_lastFileWarningsCleanCounter + 1) % LastFileWarningsCleanCycle;
+            if (_lastFileWarningsCleanCounter != 0)
+                return;
+        }
+
+        var expiredDate = DateTime.Now - LastFileWarningsMaxAge;
+        var toRemove = new HashSet<string>();
+        foreach (var (key, value) in _lastFileWarnings)
+        {
+            if (value.Item1 <= expiredDate)
+                toRemove.Add(key);
+        }
+        foreach (var key in toRemove)
+            _lastFileWarnings.Remove(key);
+    }
+
+    public void PrintFileWarning(string fullPath, Utf8GamePath originalGamePath, string messageComplement)
+    {
+        CleanLastFileWarnings(true);
+
+        // Don't warn twice for the same file within a certain time interval unless the reason changed.
+        if (_lastFileWarnings.TryGetValue(fullPath, out var lastWarning) && lastWarning.Item2 == messageComplement)
+            return;
+
+        // Don't warn for files managed by other plugins, or files we aren't sure about.
+        if (!modManager.TryIdentifyPath(fullPath, out var mod, out _))
+            return;
+
+        // Don't warn if there's no local player (as an approximation of no chat), so as not to trigger the cooldown.
+        if (clientState.LocalPlayer == null)
+            return;
+
+        // The wording is an allusion to tar's "Cowardly refusing to create an empty archive"
+        chatGui.PrintError($"Cowardly refusing to load replacement for {originalGamePath.Filename().ToString().ToLowerInvariant()} by {mod.Name}{(messageComplement.Length > 0 ? ": " : ".")}{messageComplement}", "Penumbra");
+        _lastFileWarnings[fullPath] = (DateTime.Now, messageComplement);
+    }
+}