3 files changed, 38 insertions, 1 deletions
diff --git a/login/Makefile b/login/Makefile
index 13b155d344..0a151aab6a 100644
--- a/login/Makefile
+++ b/login/Makefile
@@ -44,7 +44,9 @@ subdir-dirs = programs
 vpath %.c programs
 
 tests := tst-utmp tst-utmpx tst-grantpt tst-ptsname tst-getlogin tst-updwtmpx \
-  tst-pututxline-lockfail tst-pututxline-cache
+  tst-pututxline-lockfail tst-pututxline-cache tst-utmp-size tst-utmp-size-64
+
+CFLAGS-tst-utmp-size-64.c += -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64
 
 # Empty compatibility library for old binaries.
 extra-libs      := libutil
diff --git a/login/tst-utmp-size-64.c b/login/tst-utmp-size-64.c
new file mode 100644
index 0000000000..7a581a4c12
--- /dev/null
+++ b/login/tst-utmp-size-64.c
@@ -0,0 +1,2 @@
+/* The on-disk layout must not change in time64 mode.  */
+#include "tst-utmp-size.c"
diff --git a/login/tst-utmp-size.c b/login/tst-utmp-size.c
new file mode 100644
index 0000000000..1b7f7ff042
--- /dev/null
+++ b/login/tst-utmp-size.c
@@ -0,0 +1,33 @@
+/* Check expected sizes of struct utmp, struct utmpx, struct lastlog.
+   Copyright (C) 2024 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <utmp.h>
+#include <utmpx.h>
+#include <utmp-size.h>
+
+static int
+do_test (void)
+{
+  _Static_assert (sizeof (struct utmp) == UTMP_SIZE, "struct utmp size");
+  _Static_assert (sizeof (struct utmpx) == UTMP_SIZE, "struct utmpx size");
+  _Static_assert (sizeof (struct lastlog) == LASTLOG_SIZE,
+                  "struct lastlog size");
+  return 0;
+}
+
+#include <support/test-driver.c>