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

Change-Id: I61cde98949e47e5c8c09c33260de17f30921be79
git-subtree-dir: third_party/elfutils
git-subtree-split: 555e15ebe8bf1eb33d00747173cfc80cc65648a4
diff --git a/libdw/dwarf_begin.c b/libdw/dwarf_begin.c
new file mode 100644
index 0000000..19d16e5
--- /dev/null
+++ b/libdw/dwarf_begin.c
@@ -0,0 +1,99 @@
+/* Create descriptor from file descriptor for processing file.
+   Copyright (C) 2002, 2003, 2004, 2005 Red Hat, Inc.
+   This file is part of elfutils.
+   Written by Ulrich Drepper <drepper@redhat.com>, 2002.
+
+   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 <errno.h>
+#include <stddef.h>
+#include <sys/stat.h>
+
+#include <libdwP.h>
+
+
+Dwarf *
+dwarf_begin (int fd, Dwarf_Cmd cmd)
+{
+  Elf *elf;
+  Elf_Cmd elfcmd;
+  Dwarf *result = NULL;
+
+  switch (cmd)
+    {
+    case DWARF_C_READ:
+      elfcmd = ELF_C_READ_MMAP;
+      break;
+    case DWARF_C_WRITE:
+      elfcmd = ELF_C_WRITE;
+      break;
+    case DWARF_C_RDWR:
+      elfcmd = ELF_C_RDWR;
+      break;
+    default:
+      /* No valid mode.  */
+      __libdw_seterrno (DWARF_E_INVALID_CMD);
+      return NULL;
+    }
+
+  /* We have to call `elf_version' here since the user might have not
+     done it or initialized libelf with a different version.  This
+     would break libdwarf since we are using the ELF data structures
+     in a certain way.  */
+  elf_version (EV_CURRENT);
+
+  /* Get an ELF descriptor.  */
+  elf = elf_begin (fd, elfcmd, NULL);
+  if (elf == NULL)
+    {
+      /* Test why the `elf_begin" call failed.  */
+      struct stat st;
+
+      if (fstat (fd, &st) == 0 && ! S_ISREG (st.st_mode))
+	__libdw_seterrno (DWARF_E_NO_REGFILE);
+      else if (errno == EBADF)
+	__libdw_seterrno (DWARF_E_INVALID_FILE);
+      else
+	__libdw_seterrno (DWARF_E_IO_ERROR);
+    }
+  else
+    {
+      /* Do the real work now that we have an ELF descriptor.  */
+      result = INTUSE(dwarf_begin_elf) (elf, cmd, NULL);
+
+      /* If this failed, free the resources.  */
+      if (result == NULL)
+	elf_end (elf);
+      else
+	result->free_elf = true;
+    }
+
+  return result;
+}
+INTDEF(dwarf_begin)