1 files changed, 39 insertions, 0 deletions
diff --git a/libfshelp/perms-isowner.c b/libfshelp/perms-isowner.c
new file mode 100644
index 00000000..d1975993
--- /dev/null
+++ b/libfshelp/perms-isowner.c
@@ -0,0 +1,39 @@
+/* 
+   Copyright (C) 1999 Free Software Foundation, Inc.
+   Written by Thomas Bushnell, BSG.
+
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   The GNU Hurd is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA. */
+
+#include "fshelp.h"
+
+/* Check to see whether USER should be considered the owner of the
+   file identified by ST.  If so, return zero; otherwise return an
+   appropriate error code. */
+error_t
+fshelp_isowner (struct stat *st, struct iouser *user)
+{
+  /* Permitted if the user has the owner UID, the superuser UID, or if
+     the user is in the group of the file and has the group ID as
+     their user ID.  */
+  if (idvec_contains (user->uids, st->st_uid)
+      || idvec_contains (user->uids, 0)
+      || (idvec_contains (user->gids, st->st_gid)
+	  && idvec_contains (user->uids, st->st_gid)))
+    return 0;
+  else
+    return EPERM;
+}