diff --git a/libelf/common.h b/libelf/common.h
new file mode 100644
index 0000000..744f1bb
--- /dev/null
+++ b/libelf/common.h
@@ -0,0 +1,163 @@
+/* Common definitions for handling files in memory or only on disk.
+   Copyright (C) 1998, 1999, 2000, 2002, 2005, 2008 Red Hat, Inc.
+   This file is part of elfutils.
+   Written 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/>.  */
+
+#ifndef _COMMON_H
+#define _COMMON_H       1
+
+#include <ar.h>
+#include <byteswap.h>
+#include <endian.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "libelfP.h"
+
+static inline Elf_Kind
+__attribute__ ((unused))
+determine_kind (void *buf, size_t len)
+{
+  /* First test for an archive.  */
+  if (len >= SARMAG && memcmp (buf, ARMAG, SARMAG) == 0)
+    return ELF_K_AR;
+
+  /* Next try ELF files.  */
+  if (len >= EI_NIDENT && memcmp (buf, ELFMAG, SELFMAG) == 0)
+    {
+      /* Could be an ELF file.  */
+      int eclass = (int) ((unsigned char *) buf)[EI_CLASS];
+      int data = (int) ((unsigned char *) buf)[EI_DATA];
+      int version = (int) ((unsigned char *) buf)[EI_VERSION];
+
+      if (eclass > ELFCLASSNONE && eclass < ELFCLASSNUM
+	  && data > ELFDATANONE && data < ELFDATANUM
+	  && version > EV_NONE && version < EV_NUM)
+	return ELF_K_ELF;
+    }
+
+  /* We do not know this file type.  */
+  return ELF_K_NONE;
+}
+
+
+/* Allocate an Elf descriptor and fill in the generic information.  */
+static inline Elf *
+__attribute__ ((unused))
+allocate_elf (int fildes, void *map_address, off_t offset, size_t maxsize,
+              Elf_Cmd cmd, Elf *parent, Elf_Kind kind, size_t extra)
+{
+  Elf *result = (Elf *) calloc (1, sizeof (Elf) + extra);
+  if (result == NULL)
+    __libelf_seterrno (ELF_E_NOMEM);
+  else
+    {
+      result->kind = kind;
+      result->ref_count = 1;
+      result->cmd = cmd;
+      result->fildes = fildes;
+      result->start_offset = offset;
+      result->maximum_size = maxsize;
+      result->map_address = map_address;
+      result->parent = parent;
+
+      rwlock_init (result->lock);
+    }
+
+  return result;
+}
+
+
+/* Acquire lock for the descriptor and all children.  */
+static void
+__attribute__ ((unused))
+libelf_acquire_all (Elf *elf)
+{
+  rwlock_wrlock (elf->lock);
+
+  if (elf->kind == ELF_K_AR)
+    {
+      Elf *child = elf->state.ar.children;
+
+      while (child != NULL)
+	{
+	  if (child->ref_count != 0)
+	    libelf_acquire_all (child);
+	  child = child->next;
+	}
+    }
+}
+
+/* Release own lock and those of the children.  */
+static void
+__attribute__ ((unused))
+libelf_release_all (Elf *elf)
+{
+  if (elf->kind == ELF_K_AR)
+    {
+      Elf *child = elf->state.ar.children;
+
+      while (child != NULL)
+	{
+	  if (child->ref_count != 0)
+	    libelf_release_all (child);
+	  child = child->next;
+	}
+    }
+
+  rwlock_unlock (elf->lock);
+}
+
+
+/* Macro to convert endianess in place.  It determines the function it
+   has to use itself.  */
+#define CONVERT(Var) \
+  (Var) = (sizeof (Var) == 1						      \
+	   ? (unsigned char) (Var)					      \
+	   : (sizeof (Var) == 2						      \
+	      ? bswap_16 (Var)						      \
+	      : (sizeof (Var) == 4					      \
+		 ? bswap_32 (Var)					      \
+		 : bswap_64 (Var))))
+
+#define CONVERT_TO(Dst, Var) \
+  (Dst) = (sizeof (Var) == 1						      \
+	   ? (unsigned char) (Var)					      \
+	   : (sizeof (Var) == 2						      \
+	      ? bswap_16 (Var)						      \
+	      : (sizeof (Var) == 4					      \
+		 ? bswap_32 (Var)					      \
+		 : bswap_64 (Var))))
+
+
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+# define MY_ELFDATA	ELFDATA2LSB
+#else
+# define MY_ELFDATA	ELFDATA2MSB
+#endif
+
+#endif	/* common.h */