1 files changed, 82 insertions, 0 deletions
diff --git a/libdiskfs/io-restrict-auth.c b/libdiskfs/io-restrict-auth.c
new file mode 100644
index 00000000..0a3a5021
--- /dev/null
+++ b/libdiskfs/io-restrict-auth.c
@@ -0,0 +1,82 @@
+/* 
+   Copyright (C) 1994, 1995, 1996 Free Software Foundation
+
+   This program 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.
+
+   This program 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., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+#include "priv.h"
+#include "io_S.h"
+
+/* Tell if the array LIST (of size N) contains a member equal to QUERY. */
+static inline int
+listmember (int *list, int query, int n)
+{
+  int i;
+  for (i = 0; i < n; i++)
+    if (list[i] == query)
+      return 1;
+  return 0;
+}
+
+/* Implement io_restrict_auth as described in <hurd/io.defs>. */
+kern_return_t
+diskfs_S_io_restrict_auth (struct protid *cred,
+			   mach_port_t *newport,
+			   mach_msg_type_name_t *newportpoly,
+			   uid_t *uids,
+			   u_int nuids,
+			   gid_t *gids,
+			   u_int ngids)
+{
+  error_t err;
+  struct idvec *uvec, *gvec;
+  struct protid *newpi;
+  int i;
+  
+  if (!cred)
+    return EOPNOTSUPP;
+
+  uvec = make_idvec ();
+  gvec = make_idvec ();
+  
+  if (idvec_contains (cred->user->uids, 0))
+    {
+      /* CRED has root access, and so may use any ids.  */
+      idvec_set_ids (uvec, uids, nuids);
+      idvec_set_ids (gvec, gids, ngids);
+    }
+  else
+    {
+      /* Otherwise, use any of the requested ids that CRED already has.  */
+      for (i = 0; i < cred->user->uids->num; i++)
+	if (listmember (uids, cred->user->uids->ids[i], nuids))
+	  idvec_add (uvec, cred->user->uids->ids[i]);
+      for (i = 0; i < cred->user->gids->num; i++)
+	if (listmember (gids, cred->user->gids->ids[i], ngids))
+	  idvec_add (gvec, cred->user->gids->ids[i]);
+    }
+
+  mutex_lock (&cred->po->np->lock);
+  err = diskfs_create_protid (cred->po, iohelp_create_iouser (uvec, gvec),
+			      &newpi);
+  if (! err)
+    {
+      *newport = ports_get_right (newpi);
+      *newportpoly = MACH_MSG_TYPE_MAKE_SEND;
+      ports_port_deref (newpi);
+    }
+  mutex_unlock (&cred->po->np->lock);
+
+  return err;
+}