libdw/dwarf_begin.c

/* 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)