From: scottk@rimu.ig.utexas.edu (Scott Kempf)
Subject: patch for open(), fixes tar overwrite bug
2 Jan 1997 11:24:56 -0800
Sender: daemon@cygnus.com
Approved: cygnus.gnu-win32@cygnus.com
Distribution: cygnus
Message-ID: <199701021632.KAA12004.cygnus.gnu-win32@rimu.ig.utexas.edu>
Original-To: gnu-win32@cygnus.com
Original-Sender: owner-gnu-win32@cygnus.com

I started looking for this bug with tar's failure to overwrite files.  It
turns out the open() didn't work well for some unusual flag combinations.
The following patch fixes tar (which uses both O_TRUNC and O_APPEND)
and appears to conform to my man pages for open().

				Scott

*** cdksrc/src/winsup/fhandler.cc.orig	Mon Dec 30 17:04:41 1996
--- cdksrc/src/winsup/fhandler.cc	Mon Dec 30 17:18:01 1996
***************
*** 318,333 ****
        access_ = GENERIC_READ | GENERIC_WRITE;
      }
  
!   /* FIXME: O_EXCL handling?  */
! 
!   if (flags & O_CREAT)
!     creation_distribution = CREATE_ALWAYS;
    else
!     creation_distribution = OPEN_EXISTING;
  
    if (flags & O_APPEND) 
      {
-       creation_distribution = OPEN_ALWAYS;
        append_p_ = 1;
      }
  
--- 318,353 ----
        access_ = GENERIC_READ | GENERIC_WRITE;
      }
  
!   if ((flags & O_TRUNC) && ((flags & O_ACCMODE) != O_RDONLY))
!     {
!       if (flags & O_CREAT)
!         {
! 	  creation_distribution = CREATE_ALWAYS;
!         }
!       else
!         {
! 	  creation_distribution = TRUNCATE_EXISTING;
!         }
!     }
    else
!     {
!       if (flags & O_CREAT)
!         {
! 	  creation_distribution = OPEN_ALWAYS;
!         }
!       else
!         {
! 	  creation_distribution = OPEN_EXISTING;
!         }
!     }
! 
!   if ((flags & O_EXCL) && (flags & O_CREAT))
!     {
!       creation_distribution = CREATE_NEW;
!     }
  
    if (flags & O_APPEND) 
      {
        append_p_ = 1;
      }
  
----------------------------------
Scott Kempf (scottk@ig.utexas.edu)
Running gnu-win32 beta 17.1
under Windows 95.
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