[PATCH v14 0/1] MR10192: kernelbase: Handle \\?\ prefix in GetLongPathNameW

[Vishnunithyasoundhar S (＠svishnunithyasoundhar)]

The current implementation of GetLongPathNameW triggers a FIXME and

returns the original path when it encounters a UNC prefix. While

true network UNC paths remain unimplemented, this change allows

extended-length local paths (starting with \\?\) to be resolved by

stripping the prefix and processing the underlying local path.

This fixes issues where applications (such as xalia) passing

absolute paths with the extended-length prefix would fail to

receive a normalized or resolved long path.


```
881.036:00d4:00d8:fixme:file:GetLongPathNameW UNC pathname L"\\\\?\\Z:\\home\\vishnunithyasoundhars\\.steam\\debian-installation\\compatibilitytools.d\\debug_build\\files\\share\\wine/../xalia/xalia.exe"
```

Tested: 

After change with added debug log

```
22272.558:00d4:00d8:fixme:file:GetLongPathNameW DEBUG: Success! Returning path: L"Z:\\home\\vishnunithyasoundhars\\.steam\\debian-installation\\compatibilitytools.d\\debug_build\\files\\share\\wine/../xalia/xalia.exe" (Length: 125)
```

Signed-off-by: Vishnunithyasoundhar S [e-mail]

--
  v14: fix: extended-file-name support
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10192

[PATCH v14 1/1] fix: extended-file-name support

[Vishnunithyasoundhar S]

From: Vishnunithyasoundhar S <[e-mail]>

Signed-off-by: Vishnunithyasoundhar S <[e-mail]>
---
 dlls/kernel32/tests/path.c | 11 ++++++-----
 dlls/kernelbase/file.c     |  8 ++++++++
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/dlls/kernel32/tests/path.c b/dlls/kernel32/tests/path.c
index aa1833504d8..41481893867 100644
--- a/dlls/kernel32/tests/path.c
+++ b/dlls/kernel32/tests/path.c
@@ -360,7 +360,7 @@ static void test_InitPathA(CHAR *newdir, CHAR *curDrive, CHAR *otherDrive)
      lstrcmpiA(newdir+lstrlenA(tmppath),tmpstr1)==0,
      "GetTempFileNameA returned '%s' which doesn't match '%s' or '%s'. id=%x\n",
      newdir,tmpstr,tmpstr1,id);
-  ok(DeleteFileA(newdir),"Couldn't delete the temporary file we just created\n");     
+  ok(DeleteFileA(newdir),"Couldn't delete the temporary file we just created\n");
 
   id=GetTempFileNameA(tmppath,NULL,0,newdir);
   sprintf(tmpstr,"%.4x.tmp",id & 0xffff);
@@ -1164,12 +1164,13 @@ static void test_GetLongPathNameA(void)
     ok(length >= strlen(tempfile) + 1, "Wrong length\n");
     ok(temppath[0] == 0, "Buffer should not have been touched\n");
 
-    /* Some UNC syntax tests */
+    /* Extended file path syntax test */
 
     memset(temppath, 0, MAX_PATH);
     memset(temppath2, 0, MAX_PATH);
     lstrcpyA(temppath2, "\\\\?\\");
     lstrcatA(temppath2, tempfile);
+    trace("DEBUG: Path: %s - Length: %d\n", temppath2, (int)strlen(temppath2));
     explength = length + 4;
 
     SetLastError(0xdeadbeef);
@@ -1256,12 +1257,12 @@ static void test_GetLongPathNameW(void)
     static const WCHAR backslash[] = { '\\', 0};
     static const WCHAR letterX[] = { 'X', 0};
 
-    SetLastError(0xdeadbeef); 
+    SetLastError(0xdeadbeef);
     length = GetLongPathNameW(NULL,NULL,0);
     ok(0==length,"GetLongPathNameW returned %ld but expected 0\n",length);
     ok(GetLastError()==ERROR_INVALID_PARAMETER,"GetLastError returned %ld but expected ERROR_INVALID_PARAMETER\n",GetLastError());
 
-    SetLastError(0xdeadbeef); 
+    SetLastError(0xdeadbeef);
     empty[0]=0;
     length = GetLongPathNameW(empty,NULL,0);
     ok(0==length,"GetLongPathNameW returned %ld but expected 0\n",length);
@@ -1322,7 +1323,7 @@ static void test_GetLongPathNameW(void)
     ok(GetLastError() == ERROR_PATH_NOT_FOUND, "Expected ERROR_PATH_NOT_FOUND, got %ld\n", GetLastError());
     }
     /* With prefix */
-    expanded = 4 + (GetLongPathNameW(tempdir, NULL, 0) - 1) + lstrlenW(name) + 1 + lstrlenW(name) + 1;
+    expanded = (GetLongPathNameW(tempdir, NULL, 0) - 1) + lstrlenW(name) + 1 + lstrlenW(name) + 1;
     SetLastError(0xdeadbeef);
     length = GetLongPathNameW(shortpath, NULL, 0);
     ok(length == expanded, "Expected %ld, got %ld\n", expanded, length);
diff --git a/dlls/kernelbase/file.c b/dlls/kernelbase/file.c
index c206e2f9cc2..c9e46ab6f5b 100644
--- a/dlls/kernelbase/file.c
+++ b/dlls/kernelbase/file.c
@@ -2117,6 +2117,14 @@ DWORD WINAPI DECLSPEC_HOTPATCH GetLongPathNameW( LPCWSTR shortpath, LPWSTR longp
         return 0;
     }
 
+    /* Handle \\?\ prefix (Extended Length Path) */
+    if (shortpath[0] == '\\' && shortpath[1] == '\\' && shortpath[2] == '?' &&
+        shortpath[3] == '\\')
+    {
+      if (iswalpha(shortpath[4]) && shortpath[5] == ':' && shortpath[6] == '\\')
+        return GetLongPathNameW(shortpath + 4, longpath, longlen);
+    }
+
     if (shortpath[0] == '\\' && shortpath[1] == '\\')
     {
         FIXME( "UNC pathname %s\n", debugstr_w(shortpath) );
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/10192