elf: Add _dl_audit_objopen

It consolidates the code required to call la_objopen audit callback.

Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.

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

elf/dl-audit.c

@@ -0,0 +1,39 @@
+/* Audit common functions.
+   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 <ldsodefs.h>
+
+void
+_dl_audit_objopen (struct link_map *l, Lmid_t nsid)
+{
+  if (__glibc_likely (GLRO(dl_naudit) == 0))
+    return;
+
+  struct audit_ifaces *afct = GLRO(dl_audit);
+  for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
+    {
+      if (afct->objopen != NULL)
+	{
+	  struct auditstate *state = link_map_audit_state (l, cnt);
+	  state->bindflags = afct->objopen (l, nsid, &state->cookie);
+	  l->l_audit_any_plt |= state->bindflags != 0;
+	}
+
+      afct = afct->next;
+   }
+}