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_cntl.c b/libelf/elf_cntl.c
new file mode 100644
index 0000000..fd68178
--- /dev/null
+++ b/libelf/elf_cntl.c
@@ -0,0 +1,81 @@
+/* Control an ELF file desrciptor.
+   Copyright (C) 1998, 1999, 2000, 2002, 2015 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/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <unistd.h>
+
+#include "libelfP.h"
+
+
+int
+elf_cntl (Elf *elf, Elf_Cmd cmd)
+{
+  int result = 0;
+
+  if (elf == NULL)
+    return -1;
+
+  if (elf->fildes == -1)
+    {
+      __libelf_seterrno (ELF_E_INVALID_HANDLE);
+      return -1;
+    }
+
+  rwlock_wrlock (elf->lock);
+
+  switch (cmd)
+    {
+    case ELF_C_FDREAD:
+      /* If not all of the file is in the memory read it now.  */
+      if (elf->map_address == NULL && __libelf_readall (elf) == NULL)
+	{
+	  /* We were not able to read everything.  */
+	  result = -1;
+	  break;
+	}
+      FALLTHROUGH;
+
+    case ELF_C_FDDONE:
+      /* Mark the file descriptor as not usable.  */
+      elf->fildes = -1;
+      break;
+
+    default:
+      __libelf_seterrno (ELF_E_INVALID_CMD);
+      result = -1;
+      break;
+    }
+
+  rwlock_unlock (elf->lock);
+
+  return result;
+}