1 files changed, 67 insertions, 0 deletions
diff --git a/sysdeps/mach/hurd/setegid.c b/sysdeps/mach/hurd/setegid.c
new file mode 100644
index 0000000000..8ca4abee06
--- /dev/null
+++ b/sysdeps/mach/hurd/setegid.c
@@ -0,0 +1,67 @@
+/* Copyright (C) 1993, 1994 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <ansidecl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <hurd.h>
+#include <sys/types.h>
+#include <hurd/id.h>
+#include <string.h>
+
+/* Set the effective user ID of the calling process to GID.  */
+int
+DEFUN(setegid, (gid), gid_t gid)
+{
+  auth_t newauth;
+  error_t err;
+
+  HURD_CRITICAL_BEGIN;
+  __mutex_lock (&_hurd_id.lock);
+  err = _hurd_check_ids ();
+
+  if (!err)
+    {
+      /* Make a new auth handle which has EGID as the first element in the
+         list of effective gids.  */
+
+      size_t ngen = _hurd_id.gen.ngids < 1 ? 1 : _hurd_id.gen.ngids;
+      gid_t newgen[ngen];
+
+      newgen[0] = gid;
+      memcpy (&newgen[1], _hurd_id.gen.gids, (ngen - 1) * sizeof (gid_t));
+
+      err = __USEPORT (AUTH, __auth_makeauth
+		       (port, NULL, MACH_MSG_TYPE_COPY_SEND, 0,
+			_hurd_id.gen.uids, _hurd_id.gen.nuids,
+			_hurd_id.aux.uids, _hurd_id.aux.nuids,
+			newgen, ngen,
+			_hurd_id.aux.gids, _hurd_id.aux.ngids,
+			&newauth));
+    }
+  __mutex_unlock (&_hurd_id.lock);
+  HURD_CRITICAL_END;
+
+  if (err)
+    return __hurd_fail (err);
+
+  /* Install the new handle and reauthenticate everything.  */
+  err = __setauth (newauth);
+  __mach_port_deallocate (__mach_task_self (), newauth);
+  return err;
+}