[PATCH 0/1] MR7688: Setupapi: Don't add backslash on absolute dirid

[Anders Kjersem (＠anders)]

The absolute dirid (-1) is an empty string and should not have a backslash appended to separate it from the filename; DestinationDirs with `-1` and a file spec like `c:\foo.bin` must remain as `c:\foo.bin` after `build_filepathsW`, it must not become `\c:\foo.bin`. This also fixes a undefined access to `buffer[-1]` when src2 is an empty string!

[PATCH 1/1] Don't add backslash on empty folder

[Anders Kjersem]

From: Anders Kjersem

---
 dlls/setupapi/queue.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dlls/setupapi/queue.c b/dlls/setupapi/queue.c
index 1c43808bc5f..144d128a52d 100644
--- a/dlls/setupapi/queue.c
+++ b/dlls/setupapi/queue.c
@@ -131,7 +131,7 @@ static void concat_W( WCHAR *buffer, const WCHAR *src1, const WCHAR *src2, const
     {
         lstrcpyW( buffer, src2 );
         buffer += lstrlenW(buffer );
-        if (buffer[-1] != '\') *buffer++ = '\';
+        if (*src2 && buffer[-1] != '\') *buffer++ = '\';
         *buffer = 0;
         if (src3) while (*src3 == '\') src3++;
     }