[3/6] ntdll: Make NtWriteFile handle special offset -2 same way as -1.

[Dmitry Timoshkov]

---
 dlls/ntdll/file.c | 45 +++++++++++++++++++++++++++------------------
 1 file changed, 27 insertions(+), 18 deletions(-)

diff --git a/dlls/ntdll/file.c b/dlls/ntdll/file.c
index 9d5b02a..68700a3 100644
--- a/dlls/ntdll/file.c
+++ b/dlls/ntdll/file.c
@@ -961,36 +961,45 @@ NTSTATUS WINAPI NtWriteFile(HANDLE hFile, HANDLE hEvent,
 
     if (type == FD_TYPE_FILE)
     {
+        LARGE_INTEGER off;
+
         if (!(options & (FILE_SYNCHRONOUS_IO_ALERT | FILE_SYNCHRONOUS_IO_NONALERT)) && !offset)
         {
             status = STATUS_INVALID_PARAMETER;
             goto done;
         }
 
-        if (offset && offset->QuadPart == (LONGLONG)-1 /* FILE_WRITE_TO_END_OF_FILE */)
-            offset->QuadPart = lseek( unix_handle, 0, SEEK_END );
+        if (offset)
+        {
+            if (offset->QuadPart == (LONGLONG)-1 /* FILE_WRITE_TO_END_OF_FILE */)
+                offset->QuadPart = lseek( unix_handle, 0, SEEK_END );
+            else if (offset->QuadPart == (LONGLONG)-2 /* FILE_USE_FILE_POINTER_POSITION */)
+                offset->QuadPart = lseek( unix_handle, 0, SEEK_CUR );
+        }
+        else
+        {
+            off.QuadPart = lseek( unix_handle, 0, SEEK_CUR );
+            offset = &off;
+        }
 
-        if (offset && offset->QuadPart != (LONGLONG)-2 /* FILE_USE_FILE_POINTER_POSITION */)
+        /* async I/O doesn't make sense on regular files */
+        while ((result = pwrite( unix_handle, buffer, length, offset->QuadPart )) == -1)
         {
-            /* async I/O doesn't make sense on regular files */
-            while ((result = pwrite( unix_handle, buffer, length, offset->QuadPart )) == -1)
+            if (errno != EINTR)
             {
-                if (errno != EINTR)
-                {
-                    if (errno == EFAULT) status = STATUS_INVALID_USER_BUFFER;
-                    else status = FILE_GetNtStatus();
-                    goto done;
-                }
+                if (errno == EFAULT) status = STATUS_INVALID_USER_BUFFER;
+                else status = FILE_GetNtStatus();
+                goto done;
             }
+        }
 
-            if (options & (FILE_SYNCHRONOUS_IO_ALERT | FILE_SYNCHRONOUS_IO_NONALERT))
-                /* update file pointer position */
-                lseek( unix_handle, offset->QuadPart + result, SEEK_SET );
+        if (options & (FILE_SYNCHRONOUS_IO_ALERT | FILE_SYNCHRONOUS_IO_NONALERT))
+            /* update file pointer position */
+            lseek( unix_handle, offset->QuadPart + result, SEEK_SET );
 
-            total = result;
-            status = STATUS_SUCCESS;
-            goto done;
-        }
+        total = result;
+        status = STATUS_SUCCESS;
+        goto done;
     }
 
     for (;;)
-- 
1.8.3.4