Attempt once to create a hard link to containers before verifying the…

…m, instead of copying
nirbar · Oct 30, 2024 · 7a7ff66 · 7a7ff66
1 parent ccb6cb3
commit 7a7ff66
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Showing 2 changed files with 40 additions and 4 deletions.
diff --git a/src/burn/engine/apply.cpp b/src/burn/engine/apply.cpp
@@ -169,7 +169,8 @@ static HRESULT CopyPayload(
     __in BURN_CACHE_PROGRESS_CONTEXT* pProgress,
     __in HANDLE hSourceFile,
     __in_z LPCWSTR wzSourcePath,
-    __in_z LPCWSTR wzDestinationPath
+    __in_z LPCWSTR wzDestinationPath,
+    __in BOOL fAllowHardLink
     );
 static HRESULT DownloadPayload(
     __in BURN_CACHE_PROGRESS_CONTEXT* pProgress,
@@ -1489,7 +1490,7 @@ static HRESULT LayoutBundle(
             }
             else
             {
-                hr = CopyPayload(&progress, pContext->hSourceEngineFile, sczBundlePath, wzUnverifiedPath);
+                hr = CopyPayload(&progress, pContext->hSourceEngineFile, sczBundlePath, wzUnverifiedPath, FALSE);
                 // Error handling happens after sending complete message to BA.
 
                 // If succeeded, send 100% complete here to make sure progress was sent to the BA.
@@ -1624,6 +1625,7 @@ static HRESULT AcquireContainerOrPayload(
     DWORD64 qwFileSize = 0;
     BOOL fMinimumFileSize = FALSE;
     BOOL fEqual = FALSE;
+    BOOL fAllowHardLink = pContainer && !*pfRetry; // Not allowing hard links on payloads to ensure it isn't modified after verification. We don't mind hard links on containers because the extracted files will not be suspectible to modifications
 
     if (pContainer)
     {
@@ -1776,7 +1778,7 @@ static HRESULT AcquireContainerOrPayload(
 
         if (!fPathEqual)
         {
-            hr = CopyPayload(pProgress, INVALID_HANDLE_VALUE, pContext->rgSearchPaths[dwChosenSearchPath], wzDestinationPath);
+            hr = CopyPayload(pProgress, INVALID_HANDLE_VALUE, pContext->rgSearchPaths[dwChosenSearchPath], wzDestinationPath, fAllowHardLink);
             ExitOnFailure(hr, "Failed to copy payload: %ls", wzPayloadId);
 
             // Store the source path so it can be used as the LastUsedFolder if it passes verification.
@@ -1979,7 +1981,8 @@ static HRESULT CopyPayload(
     __in BURN_CACHE_PROGRESS_CONTEXT* pProgress,
     __in HANDLE hSourceFile,
     __in_z LPCWSTR wzSourcePath,
-    __in_z LPCWSTR wzDestinationPath
+    __in_z LPCWSTR wzDestinationPath,
+    __in BOOL fAllowHardLink
     )
 {
     HRESULT hr = S_OK;
@@ -1994,6 +1997,25 @@ static HRESULT CopyPayload(
     hr = PreparePayloadDestinationPath(wzDestinationPath);
     ExitOnFailure(hr, "Failed to prepare payload destination path: %ls", wzDestinationPath);
 
+    // Hard links are sufficient because the payload will be verified before copying to the final destination
+    if (fAllowHardLink)
+    {
+        if (::CreateHardLinkW(wzDestinationPath, wzSourcePath, NULL))
+        {
+            LARGE_INTEGER liSourceSize = { };
+            LARGE_INTEGER liZero = { };
+
+            FileSize(wzSourcePath, &liSourceSize.QuadPart);
+            CacheProgressRoutine(liSourceSize, liSourceSize, liZero, liZero, 0, CALLBACK_CHUNK_FINISHED, INVALID_HANDLE_VALUE, INVALID_HANDLE_VALUE, pProgress);
+            LogId(REPORT_STANDARD, MSG_PAYLOAD_HARD_LINK, wzSourcePath, wzDestinationPath);
+            ExitFunction();
+        }
+        else
+        {
+            LogId(REPORT_WARNING, MSG_PAYLOAD_HARD_LINK_FAILED, wzSourcePath, ::GetLastError());
+        }
+    }
+
     if (INVALID_HANDLE_VALUE == hSourceFile)
     {
         hSourceOpenedFile = ::CreateFileW(wzSourcePath, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL);

diff --git a/src/burn/engine/engine.mc b/src/burn/engine/engine.mc
@@ -1310,3 +1310,17 @@ SymbolicName=MSG_UX_PAYLOAD_MISSING
 Language=English
 UX payload deletion was detected, Id: '%1!ls!', path: '%2!ls!', action: %3!ls!.
 .
+
+MessageId=705
+Severity=Success
+SymbolicName=MSG_PAYLOAD_HARD_LINK
+Language=English
+Created a hard link from '%1!ls!' to '%2!ls!'.
+.
+
+MessageId=706
+Severity=Warning
+SymbolicName=MSG_PAYLOAD_HARD_LINK_FAILED
+Language=English
+Creating a hard link to '%1!ls!' failed with error code %2!u!. Resorting to plain copy.
+.