Squashed 'third_party/elfutils/' content from commit 555e15e

Change-Id: I61cde98949e47e5c8c09c33260de17f30921be79
git-subtree-dir: third_party/elfutils
git-subtree-split: 555e15ebe8bf1eb33d00747173cfc80cc65648a4
diff --git a/libelf/elf_getscn.c b/libelf/elf_getscn.c
new file mode 100644
index 0000000..9f7213b
--- /dev/null
+++ b/libelf/elf_getscn.c
@@ -0,0 +1,87 @@
+/* Get section at specific index.
+   Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2015 Red Hat, Inc.
+   This file is part of elfutils.
+   Contributed by Ulrich Drepper <drepper@redhat.com>, 1998.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of either
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at
+       your option) any later version
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at
+       your option) any later version
+
+   or both in parallel, as here.
+
+   elfutils 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
+   General Public License for more details.
+
+   You should have received copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdlib.h>
+
+#include "libelfP.h"
+
+
+Elf_Scn *
+elf_getscn (Elf *elf, size_t idx)
+{
+  if (elf == NULL)
+    return NULL;
+
+  if (unlikely (elf->kind != ELF_K_ELF))
+    {
+      __libelf_seterrno (ELF_E_INVALID_HANDLE);
+      return NULL;
+    }
+
+  rwlock_rdlock (elf->lock);
+
+  Elf_Scn *result = NULL;
+
+  /* Find the section in the list.  */
+  Elf_ScnList *runp = (elf->class == ELFCLASS32
+		       || (offsetof (struct Elf, state.elf32.scns)
+			   == offsetof (struct Elf, state.elf64.scns))
+		       ? &elf->state.elf32.scns : &elf->state.elf64.scns);
+  while (1)
+    {
+      if (idx < runp->max)
+	{
+	  if (idx < runp->cnt)
+	    result = &runp->data[idx];
+	  else
+	    __libelf_seterrno (ELF_E_INVALID_INDEX);
+	  break;
+	}
+
+      idx -= runp->max;
+
+      runp = runp->next;
+      if (runp == NULL)
+	{
+	  __libelf_seterrno (ELF_E_INVALID_INDEX);
+	  break;
+	}
+    }
+
+  rwlock_unlock (elf->lock);
+
+  return result;
+}
+INTDEF(elf_getscn)