diff --git a/ap/libc/glibc/glibc-2.23/stdlib/tst-secure-getenv.c b/ap/libc/glibc/glibc-2.23/stdlib/tst-secure-getenv.c
new file mode 100644
index 0000000..58208db
--- /dev/null
+++ b/ap/libc/glibc/glibc-2.23/stdlib/tst-secure-getenv.c
@@ -0,0 +1,252 @@
+/* Copyright (C) 2012-2016 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
+   <http://www.gnu.org/licenses/>.  */
+
+/* Test that secure_getenv works by invoking the test as a SGID
+   program with a group ID from the supplementary group list.  This
+   test can fail spuriously if the user is not a member of a suitable
+   supplementary group.  */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+static char MAGIC_ARGUMENT[] = "run-actual-test";
+#define MAGIC_STATUS 19
+
+static const char *test_dir;
+
+/* Return a GID which is not our current GID, but is present in the
+   supplementary group list.  */
+static gid_t
+choose_gid (void)
+{
+  const int count = 64;
+  gid_t groups[count];
+  int ret = getgroups (count, groups);
+  if (ret < 0)
+    {
+      printf ("getgroups: %m\n");
+      exit (1);
+    }
+  gid_t current = getgid ();
+  for (int i = 0; i < ret; ++i)
+    {
+      if (groups[i] != current)
+	return groups[i];
+    }
+  return 0;
+}
+
+
+/* Copies the executable into a restricted directory, so that we can
+   safely make it SGID with the TARGET group ID.  Then runs the
+   executable.  */
+static int
+run_executable_sgid (gid_t target)
+{
+  char *dirname = 0;
+  char *execname = 0;
+  int infd = -1;
+  int outfd = -1;
+  int ret = -1;
+  if (asprintf (&dirname, "%s/secure-getenv.%jd",
+		test_dir, (intmax_t) getpid ()) < 0)
+    {
+      printf ("asprintf: %m\n");
+      goto err;
+    }
+  if (mkdir (dirname, 0700) < 0)
+    {
+      printf ("mkdir: %m\n");
+      goto err;
+    }
+  if (asprintf (&execname, "%s/bin", dirname) < 0)
+    {
+      printf ("asprintf: %m\n");
+      goto err;
+    }
+  infd = open ("/proc/self/exe", O_RDONLY);
+  if (infd < 0)
+    {
+      printf ("open (/proc/self/exe): %m\n");
+      goto err;
+    }
+  outfd = open (execname, O_WRONLY | O_CREAT | O_EXCL, 0700);
+  if (outfd < 0)
+    {
+      printf ("open (%s): %m\n", execname);
+      goto err;
+    }
+  char buf[4096];
+  for (;;)
+    {
+      ssize_t rdcount = read (infd, buf, sizeof (buf));
+      if (rdcount < 0)
+	{
+	  printf ("read: %m\n");
+	  goto err;
+	}
+      if (rdcount == 0)
+	break;
+      char *p = buf;
+      char *end = buf + rdcount;
+      while (p != end)
+	{
+	  ssize_t wrcount = write (outfd, buf, end - p);
+	  if (wrcount == 0)
+	    errno = ENOSPC;
+	  if (wrcount <= 0)
+	    {
+	      printf ("write: %m\n");
+	      goto err;
+	    }
+	  p += wrcount;
+	}
+    }
+  if (fchown (outfd, getuid (), target) < 0)
+    {
+      printf ("fchown (%s): %m\n", execname);
+      goto err;
+    }
+  if (fchmod (outfd, 02750) < 0)
+    {
+      printf ("fchmod (%s): %m\n", execname);
+      goto err;
+    }
+  if (close (outfd) < 0)
+    {
+      printf ("close (outfd): %m\n");
+      goto err;
+    }
+  if (close (infd) < 0)
+    {
+      printf ("close (infd): %m\n");
+      goto err;
+    }
+
+  int kid = fork ();
+  if (kid < 0)
+    {
+      printf ("fork: %m\n");
+      goto err;
+    }
+  if (kid == 0)
+    {
+      /* Child process.  */
+      char *args[] = { execname, MAGIC_ARGUMENT, NULL };
+      execve (execname, args, environ);
+      printf ("execve (%s): %m\n", execname);
+      _exit (1);
+    }
+  int status;
+  if (waitpid (kid, &status, 0) < 0)
+    {
+      printf ("waitpid: %m\n");
+      goto err;
+    }
+  if (!WIFEXITED (status) || WEXITSTATUS (status) != MAGIC_STATUS)
+    {
+      printf ("Unexpected exit status %d from child process\n",
+	      status);
+      goto err;
+    }
+  ret = 0;
+
+err:
+  if (outfd >= 0)
+    close (outfd);
+  if (infd >= 0)
+    close (infd);
+  if (execname)
+    {
+      unlink (execname);
+      free (execname);
+    }
+  if (dirname)
+    {
+      rmdir (dirname);
+      free (dirname);
+    }
+  return ret;
+}
+
+static int
+do_test (void)
+{
+  if (getenv ("PATH") == NULL)
+    {
+      printf ("PATH not set\n");
+      exit (1);
+    }
+  if (secure_getenv ("PATH") == NULL)
+    {
+      printf ("PATH not set according to secure_getenv\n");
+      exit (1);
+    }
+  if (strcmp (getenv ("PATH"), secure_getenv ("PATH")) != 0)
+    {
+      printf ("PATH mismatch (%s, %s)\n",
+	      getenv ("PATH"), secure_getenv ("PATH"));
+      exit (1);
+    }
+
+  gid_t target = choose_gid ();
+  if (target == 0)
+    {
+      fprintf (stderr,
+	       "Could not find a suitable GID for user %jd, skipping test\n",
+	       (intmax_t) getuid ());
+      exit (0);
+    }
+  return run_executable_sgid (target);
+}
+
+static void
+alternative_main (int argc, char **argv)
+{
+  if (argc == 2 && strcmp (argv[1], MAGIC_ARGUMENT) == 0)
+    {
+      if (getgid () == getegid ())
+	{
+	  /* This can happen if the file system is mounted nosuid.  */
+	  fprintf (stderr, "SGID failed: GID and EGID match (%jd)\n",
+		  (intmax_t) getgid ());
+	  exit (MAGIC_STATUS);
+	}
+      if (getenv ("PATH") == NULL)
+	{
+	  printf ("PATH variable not present\n");
+	  exit (3);
+	}
+      if (secure_getenv ("PATH") != NULL)
+	{
+	  printf ("PATH variable not filtered out\n");
+	  exit (4);
+	}
+      exit (MAGIC_STATUS);
+    }
+}
+
+#define PREPARE(argc, argv) alternative_main(argc, argv)
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"