* devices.in (dev_storage): Map /dev/zero and /dev/full to \Device\Null.

	* devices.cc: Regenerate.
	* dtable.h (struct dtable): Make fhandler_base friend, rather
	than fhandler_disk_file.
	* fhandler.cc (fhandler_base::open_with_arch): Create unique id.
	(fhandler_base::cleanup): Call del_my_locks.
	(fhandler_base::fcntl): Handle F_GETLK, F_SETLK and F_SETLKW.
	* fhandler.h (fhandler_base::get_dev): Return real device number.
	(fhandler_base::set_unique_id): New inline method.
	(fhandler_disk_file::lock): Drop declaration.
	(fhandler_disk_file::get_dev): New method, return pc.fs_serial_number.
	(fhandler_dev_zero::open): Drop declaration.
	* fhandler_disk_file.cc (fhandler_disk_file::close): Move
	del_my_locks call to fhandler_base::open_with_arch.
	(fhandler_disk_file::fcntl): Move handling of locking commands to
	fhandler_base::fcntl.
	(fhandler_base::open_fs): Drop call to NtAllocateLocallyUniqueId.
	* fhandler_zero.cc (fhandler_dev_zero::open): Remove so that default
	fhandler_base::open is used to open \Device\Null.
	* flock.cc (fixup_lockf_after_exec): Finding a single fhandler is
	enough here.
	(fhandler_base::lock): Replace fhandler_disk_file::lock.  Refuse to lock
	nohandle devices.  Handle read/write test using POSIX flags.  Explain
	why.  Never fail on SEEK_CUR or SEEK_END, rather assume position 0,
	just as Linux.
	* net.cc (fdsock): Create unique id.

1 files changed, 19 insertions, 0 deletions

diff --git a/winsup/cygwin/fhandler.cc b/winsup/cygwin/fhandler.cc
index 2c41f31ae..6e4539c72 100644
--- a/winsup/cygwin/fhandler.cc
+++ b/winsup/cygwin/fhandler.cc
@@ -498,6 +498,12 @@ fhandler_base::open_with_arch (int flags, mode_t mode)
     }
 
   close_on_exec (flags & O_CLOEXEC);
+  /* A unique ID is necessary to recognize fhandler entries which are
+     duplicated by dup(2) or fork(2).  This is used in BSD flock calls
+     to identify the descriptor.  Skip nohandle fhandlers since advisory
+     locking is unusable for those anyway. */
+  if (!nohandle ())
+    set_unique_id ();
   return res;
 }
 
@@ -1112,6 +1118,10 @@ fhandler_base::close_with_arch ()
 void
 fhandler_base::cleanup ()
 {
+  /* Delete all POSIX locks on the file.  Delete all flock locks on the
+     file if this is the last reference to this file. */
+  if (unique_id)
+    del_my_locks (on_close);
 }
 
 int
@@ -1366,6 +1376,15 @@ int fhandler_base::fcntl (int cmd, intptr_t arg)
       }
       res = 0;
       break;
+    case F_GETLK:
+    case F_SETLK:
+    case F_SETLKW:
+	{
+	  struct flock *fl = (struct flock *) arg;
+	  fl->l_type &= F_RDLCK | F_WRLCK | F_UNLCK;
+	  res = mandatory_locking () ? mand_lock (cmd, fl) : lock (cmd, fl);
+	}
+      break;
     default:
       set_errno (EINVAL);
       res = -1;