linux: Add a getauxval test [BZ #23293]

This is for bug 23293 and it relies on the glibc test system running
tests via explicit ld.so invokation by default.

Reviewed-by: Florian Weimer <fweimer@redhat.com>

---
v4:
- New patch.

2 files changed, 75 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index ca953804d0..89cb005c7d 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -126,6 +126,7 @@ tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
   tst-prctl \
   tst-scm_rights \
   tst-epoll \
+  tst-getauxval \
   # tests
 
 # For +depfiles in Makerules.
diff --git a/sysdeps/unix/sysv/linux/tst-getauxval.c b/sysdeps/unix/sysv/linux/tst-getauxval.c
new file mode 100644
index 0000000000..c4b6195743
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-getauxval.c
@@ -0,0 +1,74 @@
+/* Basic test for getauxval.
+   Copyright (C) 2022 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 <unistd.h>
+#include <stdio.h>
+#include <support/check.h>
+#include <sys/auxv.h>
+
+static int missing;
+static int mismatch;
+
+static void
+check_nonzero (unsigned long t, const char *s)
+{
+  unsigned long v = getauxval (t);
+  printf ("%s: %lu (0x%lx)\n", s, v, v);
+  if (v == 0)
+    missing++;
+}
+
+static void
+check_eq (unsigned long t, const char *s, unsigned long want)
+{
+  unsigned long v = getauxval (t);
+  printf ("%s: %lu want: %lu\n", s, v, want);
+  if (v != want)
+    mismatch++;
+}
+
+#define NZ(x) check_nonzero (x, #x)
+#define EQ(x, want) check_eq (x, #x, want)
+
+static int
+do_test (void)
+{
+  /* These auxv entries should be non-zero on Linux.  */
+  NZ (AT_PHDR);
+  NZ (AT_PHENT);
+  NZ (AT_PHNUM);
+  NZ (AT_PAGESZ);
+  NZ (AT_ENTRY);
+  NZ (AT_CLKTCK);
+  NZ (AT_RANDOM);
+  NZ (AT_EXECFN);
+  if (missing)
+    FAIL_EXIT1 ("Found %d missing auxv entries.\n", missing);
+
+  /* Check against syscalls.  */
+  EQ (AT_UID, getuid ());
+  EQ (AT_EUID, geteuid ());
+  EQ (AT_GID, getgid ());
+  EQ (AT_EGID, getegid ());
+  if (mismatch)
+    FAIL_EXIT1 ("Found %d mismatching auxv entries.\n", mismatch);
+
+  return 0;
+}
+
+#include <support/test-driver.c>