* fhandler.cc (fhandler_base::open): Never create files with WRITE_DAC

	access.  Explain why.
	* fhandler_disk_file.cc (fhandler_base::fstat_helper): Improve debug
	output.

1 files changed, 7 insertions, 12 deletions

diff --git a/winsup/cygwin/fhandler.cc b/winsup/cygwin/fhandler.cc
index d41a37347..b72e03d60 100644
--- a/winsup/cygwin/fhandler.cc
+++ b/winsup/cygwin/fhandler.cc
@@ -613,20 +613,15 @@ fhandler_base::open (int flags, mode_t mode)
 	    /* If mode has no write bits set, and ACLs are not used, we set
 	       the DOS R/O attribute. */
 	    file_attributes |= FILE_ATTRIBUTE_READONLY;
-	  else if (!exists () && has_acls () && !isremote ())
-	    /* If we are about to create the file and the filesystem supports
-	       ACLs, we will overwrite the DACL after the call to NtCreateFile.
-	       This requires a handle with additional WRITE_DAC access,
-	       otherwise set_file_sd has to open the file again.
-	       FIXME: On remote NTFS shares open sometimes fails because even
-	       the creator of the file doesn't have the right to change the
-	       DACL.  I don't know what setting that is or howq to recognize
-	       such a share, so for now we don't request WRITE_DAC on remote
-	       drives. */
-	    access |= WRITE_DAC;
-
 	  /* The file attributes are needed for later use in, e.g. fchmod. */
 	  pc.file_attributes (file_attributes);
+	  /* Never set the WRITE_DAC flag here.  Calls to fstat may return
+	     wrong st_ctime information after calls to fchmod, fchown, etc
+	     because Windows only gurantees to update the metadata when
+	     the handle is closed or flushed.  However, flushing the file
+	     on every fstat to enforce POSIXy stat behaviour is exceessivly
+	     slow, compared to open/close the file when changing the file's
+	     security descriptor. */
 	}
     }