Fix missing metadata in Linux core dumps.

Issue #dotnet#56

Both Windows and Linux minidumps don't save all the assemblies' metadata which can cause
stack traces to display !Unknown. On Windows most debuggers like Windbg and VS can load
the module from file for this kind of dumps. On Linux lldb/SOS doesn't load the native
modules and really doesn't know anything about the managed assemblies.

Add metadata callback to datatarget and it's implementation in SOS.NETCore.

src/SOS/SOS.Hosting/LLDBServicesWrapper.cs

@@ -77,6 +77,17 @@ private delegate bool GetLocalVariableNameDelegate(
             int localIndex,
             out IntPtr localVarName);
 
+        private delegate int GetMetadataLocatorDelegate(
+            [MarshalAs(UnmanagedType.LPWStr)] string imagePath,
+            uint imageTimestamp,
+            uint imageSize,
+            [MarshalAs(UnmanagedType.LPArray, SizeConst = 16)] byte[] mvid,
+            uint mdRva,
+            uint flags,
+            uint bufferSize,
+            IntPtr buffer,
+            out uint dataSize);
+
         #endregion
 
         /// <summary>
@@ -94,6 +105,7 @@ struct SOSNetCoreCallbacks
             public ResolveSequencePointDelegate ResolveSequencePointDelegate;
             public GetLineByILOffsetDelegate GetLineByILOffsetDelegate;
             public GetLocalVariableNameDelegate GetLocalVariableNameDelegate;
+            public GetMetadataLocatorDelegate GetMetadataLocatorDelegate;
         }
 
         static SOSNetCoreCallbacks s_callbacks = new SOSNetCoreCallbacks {
@@ -105,7 +117,8 @@ struct SOSNetCoreCallbacks
             DisposeDelegate  = SymbolReader.Dispose,
             ResolveSequencePointDelegate = SymbolReader.ResolveSequencePoint,
             GetLineByILOffsetDelegate = SymbolReader.GetLineByILOffset,
-            GetLocalVariableNameDelegate  = SymbolReader.GetLocalVariableName,
+            GetLocalVariableNameDelegate = SymbolReader.GetLocalVariableName,
+            GetMetadataLocatorDelegate = MetadataHelper.GetMetadataLocator
         };
 
         static readonly string s_coreclrModuleName = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? "coreclr" : "libcoreclr.so";

src/SOS/Strike/datatarget.cpp

@@ -37,6 +37,12 @@ DataTarget::QueryInterface(
         AddRef();
         return S_OK;
     }
+    else if (InterfaceId == IID_ICLRMetadataLocator)
+    {
+        *Interface = (ICLRMetadataLocator*)this;
+        AddRef();
+        return S_OK;
+    }
     else
     {
         *Interface = NULL;
@@ -250,6 +256,8 @@ DataTarget::Request(
     return E_NOTIMPL;
 }
 
+// ICorDebugDataTarget4
+
 HRESULT STDMETHODCALLTYPE 
 DataTarget::VirtualUnwind(
     /* [in] */ DWORD threadId,
@@ -266,3 +274,27 @@ DataTarget::VirtualUnwind(
     return E_NOTIMPL;
 #endif
 }
+
+// ICLRMetadataLocator
+
+HRESULT STDMETHODCALLTYPE
+DataTarget::GetMetadata(
+    /* [in] */ LPCWSTR imagePath,
+    /* [in] */ ULONG32 imageTimestamp,
+    /* [in] */ ULONG32 imageSize,
+    /* [in] */ GUID* mvid,
+    /* [in] */ ULONG32 mdRva,
+    /* [in] */ ULONG32 flags,
+    /* [in] */ ULONG32 bufferSize,
+    /* [out, size_is(bufferSize), length_is(*dataSize)] */
+    BYTE* buffer,
+    /* [out] */ ULONG32* dataSize)
+{
+    if (g_SOSNetCoreCallbacks.GetMetadataLocatorDelegate == nullptr)
+    {
+        return E_FAIL;
+    }
+    return g_SOSNetCoreCallbacks.GetMetadataLocatorDelegate(imagePath, imageTimestamp, imageSize, mvid, mdRva, flags, bufferSize, buffer, dataSize);
+}
+
+

src/SOS/Strike/datatarget.h

@@ -2,7 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-class DataTarget : public ICLRDataTarget, ICorDebugDataTarget4
+class DataTarget : public ICLRDataTarget, ICorDebugDataTarget4, ICLRMetadataLocator
 {
 private:
     LONG m_ref;                         // Reference count.
@@ -87,4 +87,18 @@ class DataTarget : public ICLRDataTarget, ICorDebugDataTarget4
         /* [in] */ DWORD threadId,
         /* [in] */ ULONG32 contextSize,
         /* [in, out, size_is(contextSize)] */ PBYTE context);
+
+    // ICLRMetadataLocator
+
+    virtual HRESULT STDMETHODCALLTYPE GetMetadata(
+        /* [in] */ LPCWSTR imagePath,
+        /* [in] */ ULONG32 imageTimestamp,
+        /* [in] */ ULONG32 imageSize,
+        /* [in] */ GUID* mvid,
+        /* [in] */ ULONG32 mdRva,
+        /* [in] */ ULONG32 flags,
+        /* [in] */ ULONG32 bufferSize,
+        /* [out, size_is(bufferSize), length_is(*dataSize)] */
+        BYTE* buffer,
+        /* [out] */ ULONG32* dataSize);
 };

src/SOS/Strike/hostcoreclr.cpp

@@ -66,7 +66,7 @@ static void AddFilesFromDirectoryToTpaList(const char* directory, std::string& t
     std::set<std::string> addedAssemblies;
 
     // Don't add this file to the list because we don't want to the one from the hosting runtime
-    addedAssemblies.insert(SymbolReaderDllName);
+    addedAssemblies.insert(SOSManagedDllName);
 
     // Walk the directory for each extension separately so that we first get files with .ni.dll extension,
     // then files with .dll extension, etc.
@@ -679,15 +679,16 @@ HRESULT InitializeHosting()
         return Status;
     }
 
-    IfFailRet(createDelegate(hostHandle, domainId, SymbolReaderDllName, SymbolReaderClassName, "InitializeSymbolStore", (void **)&g_SOSNetCoreCallbacks.InitializeSymbolStoreDelegate));
-    IfFailRet(createDelegate(hostHandle, domainId, SymbolReaderDllName, SymbolReaderClassName, "DisplaySymbolStore", (void **)&g_SOSNetCoreCallbacks.DisplaySymbolStoreDelegate));
-    IfFailRet(createDelegate(hostHandle, domainId, SymbolReaderDllName, SymbolReaderClassName, "DisableSymbolStore", (void **)&g_SOSNetCoreCallbacks.DisableSymbolStoreDelegate));
-    IfFailRet(createDelegate(hostHandle, domainId, SymbolReaderDllName, SymbolReaderClassName, "LoadNativeSymbols", (void **)&g_SOSNetCoreCallbacks.LoadNativeSymbolsDelegate));
-    IfFailRet(createDelegate(hostHandle, domainId, SymbolReaderDllName, SymbolReaderClassName, "LoadSymbolsForModule", (void **)&g_SOSNetCoreCallbacks.LoadSymbolsForModuleDelegate));
-    IfFailRet(createDelegate(hostHandle, domainId, SymbolReaderDllName, SymbolReaderClassName, "Dispose", (void **)&g_SOSNetCoreCallbacks.DisposeDelegate));
-    IfFailRet(createDelegate(hostHandle, domainId, SymbolReaderDllName, SymbolReaderClassName, "ResolveSequencePoint", (void **)&g_SOSNetCoreCallbacks.ResolveSequencePointDelegate));
-    IfFailRet(createDelegate(hostHandle, domainId, SymbolReaderDllName, SymbolReaderClassName, "GetLocalVariableName", (void **)&g_SOSNetCoreCallbacks.GetLocalVariableNameDelegate));
-    IfFailRet(createDelegate(hostHandle, domainId, SymbolReaderDllName, SymbolReaderClassName, "GetLineByILOffset", (void **)&g_SOSNetCoreCallbacks.GetLineByILOffsetDelegate));
+    IfFailRet(createDelegate(hostHandle, domainId, SOSManagedDllName, SymbolReaderClassName, "InitializeSymbolStore", (void **)&g_SOSNetCoreCallbacks.InitializeSymbolStoreDelegate));
+    IfFailRet(createDelegate(hostHandle, domainId, SOSManagedDllName, SymbolReaderClassName, "DisplaySymbolStore", (void **)&g_SOSNetCoreCallbacks.DisplaySymbolStoreDelegate));
+    IfFailRet(createDelegate(hostHandle, domainId, SOSManagedDllName, SymbolReaderClassName, "DisableSymbolStore", (void **)&g_SOSNetCoreCallbacks.DisableSymbolStoreDelegate));
+    IfFailRet(createDelegate(hostHandle, domainId, SOSManagedDllName, SymbolReaderClassName, "LoadNativeSymbols", (void **)&g_SOSNetCoreCallbacks.LoadNativeSymbolsDelegate));
+    IfFailRet(createDelegate(hostHandle, domainId, SOSManagedDllName, SymbolReaderClassName, "LoadSymbolsForModule", (void **)&g_SOSNetCoreCallbacks.LoadSymbolsForModuleDelegate));
+    IfFailRet(createDelegate(hostHandle, domainId, SOSManagedDllName, SymbolReaderClassName, "Dispose", (void **)&g_SOSNetCoreCallbacks.DisposeDelegate));
+    IfFailRet(createDelegate(hostHandle, domainId, SOSManagedDllName, SymbolReaderClassName, "ResolveSequencePoint", (void **)&g_SOSNetCoreCallbacks.ResolveSequencePointDelegate));
+    IfFailRet(createDelegate(hostHandle, domainId, SOSManagedDllName, SymbolReaderClassName, "GetLocalVariableName", (void **)&g_SOSNetCoreCallbacks.GetLocalVariableNameDelegate));
+    IfFailRet(createDelegate(hostHandle, domainId, SOSManagedDllName, SymbolReaderClassName, "GetLineByILOffset", (void **)&g_SOSNetCoreCallbacks.GetLineByILOffsetDelegate));
+    IfFailRet(createDelegate(hostHandle, domainId, SOSManagedDllName, MetadataHelperClassName, "GetMetadataLocator", (void **)&g_SOSNetCoreCallbacks.GetMetadataLocatorDelegate));
 
     g_hostingInitialized = true;
     return Status;

src/SOS/Strike/hostcoreclr.h

@@ -12,8 +12,9 @@
 
 #include <soshostservices.h>
 
-static const char *SymbolReaderDllName = "SOS.NETCore";
+static const char *SOSManagedDllName = "SOS.NETCore";
 static const char *SymbolReaderClassName = "SOS.SymbolReader";
+static const char *MetadataHelperClassName = "SOS.MetadataHelper";
 
 extern HMODULE g_hInstance;
 extern LPCSTR g_hostRuntimeDirectory;

src/SOS/Strike/soshostservices.h

@@ -34,7 +34,19 @@ typedef  BOOL (*ResolveSequencePointDelegate)(PVOID, const char*, unsigned int,
 typedef  BOOL (*GetLocalVariableNameDelegate)(PVOID, int, int, BSTR*);
 typedef  BOOL (*GetLineByILOffsetDelegate)(PVOID, mdMethodDef, ULONG64, ULONG *, BSTR*);
 
-#define SOSNetCoreCallbacksVersion 1
+typedef  BOOL (*GetMetadataLocatorDelegate)(
+    LPCWSTR imagePath,
+    unsigned int imageTimestamp,
+    unsigned int imageSize,
+    GUID* mvid,
+    unsigned int mdRva,
+    unsigned int flags,
+    unsigned int bufferSize,
+    PVOID buffer,
+    unsigned int* dataSize
+);
+
+#define SOSNetCoreCallbacksVersion 2
 
 struct SOSNetCoreCallbacks
 {
@@ -47,6 +59,7 @@ struct SOSNetCoreCallbacks
     ResolveSequencePointDelegate ResolveSequencePointDelegate;
     GetLineByILOffsetDelegate GetLineByILOffsetDelegate;
     GetLocalVariableNameDelegate GetLocalVariableNameDelegate;
+    GetMetadataLocatorDelegate GetMetadataLocatorDelegate;
 };
 
 MIDL_INTERFACE("D13608FB-AD14-4B49-990A-80284F934C41")