Remove 'grp' and merge into 'nss' and 'posix'

The majority of grp routines are entry points for nss functionality.
This commit removes the 'grp' subdirectory and moves all nss-relevant
functionality and all tests to 'nss', and the 'setgroups' stub into
'posix' (alongside the 'getgroups' stub).  References to grp/ are
accordingly changed.  In addition, compat-initgroups.c, a fallback
implementation of initgroups is renamed to initgroups-fallback.c so that
the build system does not confuse it for nss_compat/compat-initgroups.c.

Build time improves very slightly; e.g. down from an average of 45.5s to
44.5s on an 8-thread mobile x86_64 CPU.
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 56 insertions, 0 deletions

diff --git a/nss/tst-initgroups1.c b/nss/tst-initgroups1.c
new file mode 100644
index 0000000000..3f1238875e
--- /dev/null
+++ b/nss/tst-initgroups1.c
@@ -0,0 +1,56 @@
+/* Test that initgroups works.
+   Copyright (C) 2020-2023 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 <nss.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <errno.h>
+#include <unistd.h>
+#include <grp.h>
+
+#include <support/support.h>
+#include <support/check.h>
+
+/* Test that initgroups includes secondary groups.
+   https://bugzilla.redhat.com/show_bug.cgi?id=1906066  */
+
+/* This version uses the wrapper around the groups module.  */
+
+#define EXPECTED_N_GROUPS 4
+static gid_t expected_groups[] =
+  { 20, 30, 50, 51 };
+
+static int
+do_test (void)
+{
+  gid_t mygroups [50];
+  int i, n;
+
+  n = 50;
+  getgrouplist ("dj", 20, mygroups, &n);
+
+  TEST_COMPARE (n, EXPECTED_N_GROUPS);
+  for (i=0; i<n; i++)
+    TEST_COMPARE (mygroups[i], expected_groups[i]);
+
+  return 0;
+}
+
+#include <support/test-driver.c>