x86/CET: Add tests with legacy shared objects

diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
index e9b2d0b35d..92a53bb763 100644
--- a/sysdeps/x86/Makefile
+++ b/sysdeps/x86/Makefile
@@ -17,6 +17,43 @@  endif
 ifeq ($(enable-cet),yes)
 ifeq ($(subdir),elf)
 sysdep-dl-routines += dl-cet
+
+tests += tst-legacy-1 tst-legacy-2 tst-legacy-2a tst-legacy-3 \
+	 tst-legacy-4
+ifneq (no,$(have-tunables))
+tests += tst-legacy-4a tst-legacy-4b tst-legacy-4c
+endif
+modules-names += tst-legacy-mod-1 tst-legacy-mod-2 tst-legacy-mod-4
+
+CFLAGS-tst-legacy-2.c += -fcf-protection=branch
+CFLAGS-tst-legacy-2a.c += -fcf-protection
+CFLAGS-tst-legacy-mod-1.c += -fcf-protection=none
+CFLAGS-tst-legacy-mod-2.c += -fcf-protection=none
+CFLAGS-tst-legacy-3.c += -fcf-protection=none
+CFLAGS-tst-legacy-4.c += -fcf-protection=branch
+CFLAGS-tst-legacy-4a.c += -fcf-protection
+CFLAGS-tst-legacy-4b.c += -fcf-protection
+CFLAGS-tst-legacy-mod-4.c += -fcf-protection=none
+
+$(objpfx)tst-legacy-1: $(objpfx)tst-legacy-mod-1.so \
+		       $(objpfx)tst-legacy-mod-2.so
+$(objpfx)tst-legacy-2: $(objpfx)tst-legacy-mod-2.so $(libdl)
+$(objpfx)tst-legacy-2.out: $(objpfx)tst-legacy-mod-1.so
+$(objpfx)tst-legacy-2a: $(objpfx)tst-legacy-mod-2.so $(libdl)
+$(objpfx)tst-legacy-2a.out: $(objpfx)tst-legacy-mod-1.so
+$(objpfx)tst-legacy-4: $(libdl)
+$(objpfx)tst-legacy-4.out: $(objpfx)tst-legacy-mod-4.so
+ifneq (no,$(have-tunables))
+$(objpfx)tst-legacy-4a: $(libdl)
+$(objpfx)tst-legacy-4a.out: $(objpfx)tst-legacy-mod-4.so
+tst-legacy-4a-ENV = GLIBC_TUNABLES=glibc.tune.x86_shstk=permissive
+$(objpfx)tst-legacy-4b: $(libdl)
+$(objpfx)tst-legacy-4b.out: $(objpfx)tst-legacy-mod-4.so
+tst-legacy-4b-ENV = GLIBC_TUNABLES=glibc.tune.x86_shstk=on
+$(objpfx)tst-legacy-4c: $(libdl)
+$(objpfx)tst-legacy-4c.out: $(objpfx)tst-legacy-mod-4.so
+tst-legacy-4c-ENV = GLIBC_TUNABLES=glibc.tune.x86_shstk=off
+endif
 endif
 
 # Add -fcf-protection to CFLAGS when CET is enabled.
diff --git a/sysdeps/x86/tst-legacy-1.c b/sysdeps/x86/tst-legacy-1.c
new file mode 100644
index 0000000000..861c09a26e
--- /dev/null
+++ b/sysdeps/x86/tst-legacy-1.c
@@ -0,0 +1,44 @@ 
+/* Check compatibility of CET-enabled executable linked with legacy
+   shared object.
+   Copyright (C) 2018 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/>.  */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+extern int in_dso_1 (void);
+extern int in_dso_2 (void);
+
+static int
+do_test (void)
+{
+  if (in_dso_1 () != 0x1234678)
+    {
+      puts ("in_dso_1 () != 0x1234678");
+      exit (1);
+    }
+
+  if (in_dso_2 () != 0xbadbeef)
+    {
+      puts ("in_dso_2 () != 0xbadbeef");
+      exit (1);
+    }
+
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/sysdeps/x86/tst-legacy-2.c b/sysdeps/x86/tst-legacy-2.c
new file mode 100644
index 0000000000..2e6b9c4078
--- /dev/null
+++ b/sysdeps/x86/tst-legacy-2.c
@@ -0,0 +1,64 @@ 
+/* Check compatibility of CET-enabled executable with dlopened legacy
+   shared object.
+   Copyright (C) 2018 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/>.  */
+
+#include <dlfcn.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+extern int in_dso_2 (void);
+
+static int
+do_test (void)
+{
+  static const char modname[] = "tst-legacy-mod-1.so";
+  int (*fp) (void);
+  void *h;
+
+  h = dlopen (modname, RTLD_LAZY);
+  if (h == NULL)
+    {
+      printf ("cannot open '%s': %s\n", modname, dlerror ());
+      exit (1);
+    }
+
+  fp = dlsym (h, "in_dso_1");
+  if (fp == NULL)
+    {
+      printf ("cannot get symbol 'in_dso': %s\n", dlerror ());
+      exit (1);
+    }
+
+  if (fp () != 0x1234678)
+    {
+      puts ("in_dso_1 () != 0x1234678");
+      exit (1);
+    }
+
+  if (in_dso_2 () != 0xbadbeef)
+    {
+      puts ("in_dso_2 () != 0xbadbeef");
+      exit (1);
+    }
+
+  dlclose (h);
+
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/sysdeps/x86/tst-legacy-2a.c b/sysdeps/x86/tst-legacy-2a.c
new file mode 100644
index 0000000000..1f4405a661
--- /dev/null
+++ b/sysdeps/x86/tst-legacy-2a.c
@@ -0,0 +1 @@ 
+#include "tst-legacy-2.c"
diff --git a/sysdeps/x86/tst-legacy-3.c b/sysdeps/x86/tst-legacy-3.c
new file mode 100644
index 0000000000..7bf0e656b1
--- /dev/null
+++ b/sysdeps/x86/tst-legacy-3.c
@@ -0,0 +1,88 @@ 
+/* Check compatibility of CET-enabled executable with dlopened legacy
+   shared object.  Copied from gcc.target/i386/pr81128.c in GCC testsuite.
+   Copyright (C) 2018 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/>.  */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+int resolver_fn = 0;
+int resolved_fn = 0;
+
+static inline void
+do_it_right_at_runtime_A (void)
+{
+  resolved_fn++;
+}
+
+static inline void
+do_it_right_at_runtime_B (void)
+{
+  resolved_fn++;
+}
+
+static inline void do_it_right_at_runtime (void);
+
+void do_it_right_at_runtime (void)
+  __attribute__ ((ifunc ("resolve_do_it_right_at_runtime")));
+
+static void (*resolve_do_it_right_at_runtime (void)) (void)
+{
+  srand (time (NULL));
+  int r = rand ();
+  resolver_fn++;
+
+  /* Use intermediate variable to get a warning for non-matching
+   * prototype. */
+  typeof(do_it_right_at_runtime) *func;
+  if (r & 1)
+    func = do_it_right_at_runtime_A;
+  else
+    func = do_it_right_at_runtime_B;
+
+  return (void *) func;
+}
+
+int
+test (void)
+{
+  const unsigned int ITERS = 10;
+
+  for (int i = ITERS; i > 0; i--)
+    {
+      do_it_right_at_runtime ();
+    }
+
+  if (resolver_fn != 1)
+    __builtin_abort ();
+
+  if (resolved_fn != 10)
+    __builtin_abort ();
+
+  return 0;
+}
+
+#ifndef TEST_MODULE
+static int
+do_test (void)
+{
+  return test ();
+}
+
+#include <support/test-driver.c>
+#endif
diff --git a/sysdeps/x86/tst-legacy-4.c b/sysdeps/x86/tst-legacy-4.c
new file mode 100644
index 0000000000..50f53aa1f9
--- /dev/null
+++ b/sysdeps/x86/tst-legacy-4.c
@@ -0,0 +1,56 @@ 
+/* Check compatibility of CET-enabled executable with dlopened legacy
+   shared object.
+   Copyright (C) 2018 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/>.  */
+
+#include <dlfcn.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+static int
+do_test (void)
+{
+  static const char modname[] = "tst-legacy-mod-4.so";
+  int (*fp) (void);
+  void *h;
+
+  h = dlopen (modname, RTLD_LAZY);
+  if (h == NULL)
+    {
+      printf ("cannot open '%s': %s\n", modname, dlerror ());
+      exit (1);
+    }
+
+  fp = dlsym (h, "test");
+  if (fp == NULL)
+    {
+      printf ("cannot get symbol 'test': %s\n", dlerror ());
+      exit (1);
+    }
+
+  if (fp () != 0)
+    {
+      puts ("test () != 0");
+      exit (1);
+    }
+
+  dlclose (h);
+
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/sysdeps/x86/tst-legacy-4a.c b/sysdeps/x86/tst-legacy-4a.c
new file mode 100644
index 0000000000..0aee4f1161
--- /dev/null
+++ b/sysdeps/x86/tst-legacy-4a.c
@@ -0,0 +1 @@ 
+#include "tst-legacy-4.c"
diff --git a/sysdeps/x86/tst-legacy-4b.c b/sysdeps/x86/tst-legacy-4b.c
new file mode 100644
index 0000000000..0aee4f1161
--- /dev/null
+++ b/sysdeps/x86/tst-legacy-4b.c
@@ -0,0 +1 @@ 
+#include "tst-legacy-4.c"
diff --git a/sysdeps/x86/tst-legacy-4c.c b/sysdeps/x86/tst-legacy-4c.c
new file mode 100644
index 0000000000..0aee4f1161
--- /dev/null
+++ b/sysdeps/x86/tst-legacy-4c.c
@@ -0,0 +1 @@ 
+#include "tst-legacy-4.c"
diff --git a/sysdeps/x86/tst-legacy-mod-1.c b/sysdeps/x86/tst-legacy-mod-1.c
new file mode 100644
index 0000000000..09762bce13
--- /dev/null
+++ b/sysdeps/x86/tst-legacy-mod-1.c
@@ -0,0 +1,24 @@ 
+/* Check compatibility of CET-enabled executable with legacy shared
+   object.
+   Copyright (C) 2018 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/>.  */
+
+int
+in_dso_1 (void)
+{
+  return 0x1234678;
+}
diff --git a/sysdeps/x86/tst-legacy-mod-2.c b/sysdeps/x86/tst-legacy-mod-2.c
new file mode 100644
index 0000000000..1c8de443f6
--- /dev/null
+++ b/sysdeps/x86/tst-legacy-mod-2.c
@@ -0,0 +1,24 @@ 
+/* Check compatibility of CET-enabled executable with legacy shared
+   object.
+   Copyright (C) 2018 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/>.  */
+
+int
+in_dso_2 (void)
+{
+  return 0xbadbeef;
+}
diff --git a/sysdeps/x86/tst-legacy-mod-4.c b/sysdeps/x86/tst-legacy-mod-4.c
new file mode 100644
index 0000000000..d808623676
--- /dev/null
+++ b/sysdeps/x86/tst-legacy-mod-4.c
@@ -0,0 +1,2 @@ 
+#define TEST_MODULE
+#include "tst-legacy-3.c"