[PATCH 3/3] ntdll: The maximum length for a path is MAX_PATH.

[Jiajin Cui]

From: Jiajin Cui

see "https://learn.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-lim...".

Signed-off-by: Jiajin Cui 
---
 dlls/ntdll/path.c | 85 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)

diff --git a/dlls/ntdll/path.c b/dlls/ntdll/path.c
index 37ad4bbcea2..b844b19ba72 100644
--- a/dlls/ntdll/path.c
+++ b/dlls/ntdll/path.c
@@ -33,6 +33,11 @@ WINE_DEFAULT_DEBUG_CHANNEL(file);

#define IS_SEPARATOR(ch)  ((ch) == '\' || (ch) == '/')

+#define LONGPATH_INIT 0
+#define LONGPATH_ENABLE 1
+#define LONGPATH_DISABLE -1
+static DWORD longpathenable = LONGPATH_INIT;
+
 /***********************************************************************
  *             RtlDetermineDosPathNameType_U   (NTDLL.@)
  */
@@ -163,6 +168,79 @@ static BOOL is_valid_directory(LPCWSTR path)
     return TRUE;
 }

+static NTSTATUS query_dword_option( HANDLE hkey, LPCWSTR name, LONG *value )
+{
+    NTSTATUS status;
+    UNICODE_STRING str;
+    ULONG size;
+    WCHAR buffer[64];
+    KEY_VALUE_PARTIAL_INFORMATION *info = (KEY_VALUE_PARTIAL_INFORMATION *)buffer;
+
+    RtlInitUnicodeString( &str, name );
+
+    size = sizeof(buffer) - sizeof(WCHAR);
+    if ((status = NtQueryValueKey( hkey, &str, KeyValuePartialInformation, buffer, size, &size )))
+        return status;
+
+    if (info->Type != REG_DWORD)
+    {
+        buffer[size / sizeof(WCHAR)] = 0;
+        *value = wcstoul( (WCHAR *)info->Data, 0, 16 );
+    }
+    else memcpy( value, info->Data, sizeof(*value) );
+    return status;
+}
+
+static DWORD getLongPathsEnabled()
+{
+    OBJECT_ATTRIBUTES attr = { sizeof(attr) };
+    UNICODE_STRING name;
+    HANDLE mutex;
+    static HKEY hklm;
+
+    static WCHAR longpath_mutexW[] =
+        {'\','B','a','s','e','N','a','m','e','d','O','b','j','e','c','t','s',
+         '\','_','_','L','O','N','G','_','P','A','T','H','_','M','U','T','E','X','_','_'};
+
+    attr.Attributes = OBJ_OPENIF;
+    attr.ObjectName = &name;
+    name.Buffer = longpath_mutexW;
+    name.Length = name.MaximumLength = sizeof(longpath_mutexW);
+
+    if (NtCreateMutant( &mutex, MUTEX_ALL_ACCESS, &attr, FALSE ) < 0) return 0;
+    NtWaitForSingleObject( mutex, FALSE, NULL );
+
+    if(LONGPATH_INIT == longpathenable)
+    {
+        static const WCHAR filesystemW[] = {'\','R','e','g','i','s','t','r','y',
+            '\','M','a','c','h','i','n','e',
+            '\','S','y','s','t','e','m',
+            '\','C','u','r','r','e','n','t','C','o','n','t','r','o','l','S','e','t',
+            '\','C','o','n','t','r','o','l',
+            '\','F','i','l','e','S','y','s','t','e','m',0};
+        static const WCHAR longpathenableW[] = {'L','o','n','g','P','a','t','h','s','E','n','a','b','l','e','d',0};
+        OBJECT_ATTRIBUTES attr;
+        UNICODE_STRING nameW;
+        HANDLE key;
+
+        InitializeObjectAttributes( &attr, &nameW, 0, 0, NULL );
+        nameW.Buffer = filesystemW;
+        nameW.Length = sizeof(filesystemW);
+        nameW.MaximumLength = nameW.Length;
+        if (!NtOpenKey( &key, KEY_READ, &attr ))
+        {
+            query_dword_option( key, longpathenableW, &longpathenable );
+            NtClose( key );
+        }
+    }
+
+    if(LONGPATH_ENABLE != longpathenable) longpathenable = LONGPATH_DISABLE;
+
+    NtReleaseMutant( mutex, NULL );
+
+    return longpathenable;
+}
+
 /**************************************************************************
  *                 RtlDosPathNameToNtPathName_U_WithStatus    [NTDLL.@]
  *
@@ -196,6 +274,13 @@ NTSTATUS WINAPI RtlDosPathNameToNtPathName_U_WithStatus(const WCHAR *dos_path, U
     if (!dos_path || !*dos_path)
         return STATUS_OBJECT_NAME_INVALID;

+    if( LONGPATH_ENABLE != getLongPathsEnabled() 
+        && memcmp(dos_path, global_prefix, sizeof(global_prefix)) 
+        && wcslen(dos_path) > MAX_PATH )
+    {
+        return STATUS_OBJECT_NAME_INVALID;
+    }
+
     if (!memcmp(dos_path, global_prefix, sizeof(global_prefix)) ||
         (!memcmp(dos_path, global_prefix2, sizeof(global_prefix2)) && dos_path[4]) ||
         !wcsicmp( dos_path, L"\\.\CON" ))