Add static tests for __clone_internal

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

sysdeps/unix/sysv/linux/tst-align-clone-internal.c

@@ -0,0 +1,68 @@
+/* Verify that the clone child stack is properly aligned.
+   Copyright (C) 2021 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 <sched.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <tst-stack-align.h>
+#include <clone_internal.h>
+#include <support/xunistd.h>
+#include <support/check.h>
+
+static int
+f (void *arg)
+{
+  puts ("in f");
+
+  return TEST_STACK_ALIGN () ? 1 : 0;
+}
+
+static int
+do_test (void)
+{
+  puts ("in main");
+
+  if (TEST_STACK_ALIGN ())
+    FAIL_EXIT1 ("stack alignment failed");
+
+#ifdef __ia64__
+# define STACK_SIZE 256 * 1024
+#else
+# define STACK_SIZE 128 * 1024
+#endif
+  char st[STACK_SIZE] __attribute__ ((aligned));
+  struct clone_args clone_args =
+    {
+      .stack = (uintptr_t) st,
+      .stack_size = sizeof (st),
+    };
+  pid_t p = __clone_internal (&clone_args, f, 0);
+  TEST_VERIFY (p != -1);
+
+  int e;
+  xwaitpid (p, &e, __WCLONE);
+  TEST_VERIFY (WIFEXITED (e));
+  TEST_COMPARE (WEXITSTATUS (e), 0);
+  return 0;
+}
+
+#include <support/test-driver.c>