[newlib-cygwin] Cygwin: fstat_helper: always use handle in call to get_file_attribute

[Ken Brown <kbrown@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=76dca77f049271e2529c25de8a396e65dbce615d

commit 76dca77f049271e2529c25de8a396e65dbce615d
Author: Ken Brown <kbrown@cornell.edu>
Date:   Thu Jan 30 10:08:21 2020 -0500

    Cygwin: fstat_helper: always use handle in call to get_file_attribute
    
    When fhandler_base::fstat_helper is called, the handle h returned by
    get_stat_handle() should be pc.handle() and should be safe to use for
    getting the file information.  Previously, the call to
    get_file_attribute() for FIFOs set the first argument to NULL instead
    of h, thereby forcing the file to be opened for fetching the security
    descriptor in get_file_sd().

Diff:
---
 winsup/cygwin/fhandler_disk_file.cc | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/winsup/cygwin/fhandler_disk_file.cc b/winsup/cygwin/fhandler_disk_file.cc
index f362e31..bc5967e 100644
--- a/winsup/cygwin/fhandler_disk_file.cc
+++ b/winsup/cygwin/fhandler_disk_file.cc
@@ -394,12 +394,13 @@ fhandler_base::fstat_fs (struct stat *buf)
   return res;
 }
 
+/* Called by fstat_by_handle and fstat_by_name. */
 int __reg2
 fhandler_base::fstat_helper (struct stat *buf)
 {
   IO_STATUS_BLOCK st;
   FILE_COMPRESSION_INFORMATION fci;
-  HANDLE h = get_stat_handle ();
+  HANDLE h = get_stat_handle ();      /* Should always be pc.handle(). */
   PFILE_ALL_INFORMATION pfai = pc.fai ();
   ULONG attributes = pc.file_attributes ();
 
@@ -475,8 +476,8 @@ fhandler_base::fstat_helper (struct stat *buf)
   else if (pc.issocket ())
     buf->st_mode = S_IFSOCK;
 
-  if (!get_file_attribute (is_fs_special () && !pc.issocket () ? NULL : h, pc,
-			   &buf->st_mode, &buf->st_uid, &buf->st_gid))
+  if (!get_file_attribute (h, pc, &buf->st_mode, &buf->st_uid,
+			   &buf->st_gid))
     {
       /* If read-only attribute is set, modify ntsec return value */
       if (::has_attribute (attributes, FILE_ATTRIBUTE_READONLY)