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      1 /* Return reference offset represented by attribute.
      2    Copyright (C) 2003-2010, 2014 Red Hat, Inc.
      3    This file is part of elfutils.
      4    Written by Ulrich Drepper <drepper (at) redhat.com>, 2003.
      5 
      6    This file is free software; you can redistribute it and/or modify
      7    it under the terms of either
      8 
      9      * the GNU Lesser General Public License as published by the Free
     10        Software Foundation; either version 3 of the License, or (at
     11        your option) any later version
     12 
     13    or
     14 
     15      * the GNU General Public License as published by the Free
     16        Software Foundation; either version 2 of the License, or (at
     17        your option) any later version
     18 
     19    or both in parallel, as here.
     20 
     21    elfutils is distributed in the hope that it will be useful, but
     22    WITHOUT ANY WARRANTY; without even the implied warranty of
     23    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     24    General Public License for more details.
     25 
     26    You should have received copies of the GNU General Public License and
     27    the GNU Lesser General Public License along with this program.  If
     28    not, see <http://www.gnu.org/licenses/>.  */
     29 
     30 #ifdef HAVE_CONFIG_H
     31 # include <config.h>
     32 #endif
     33 
     34 #include <dwarf.h>
     35 #include "libdwP.h"
     36 
     37 int
     38 internal_function
     39 __libdw_formref (Dwarf_Attribute *attr, Dwarf_Off *return_offset)
     40 {
     41   const unsigned char *datap = attr->valp;
     42   const unsigned char *endp = attr->cu->endp;
     43 
     44   if (attr->valp == NULL)
     45     {
     46       __libdw_seterrno (DWARF_E_INVALID_REFERENCE);
     47       return -1;
     48     }
     49 
     50   switch (attr->form)
     51     {
     52     case DW_FORM_ref1:
     53       if (datap + 1 > endp)
     54 	{
     55 	invalid:
     56 	  __libdw_seterrno (DWARF_E_INVALID_DWARF);
     57 	  return -1;
     58 	}
     59       *return_offset = *attr->valp;
     60       break;
     61 
     62     case DW_FORM_ref2:
     63       if (datap + 2 > endp)
     64 	goto invalid;
     65       *return_offset = read_2ubyte_unaligned (attr->cu->dbg, attr->valp);
     66       break;
     67 
     68     case DW_FORM_ref4:
     69       if (datap + 4 > endp)
     70 	goto invalid;
     71       *return_offset = read_4ubyte_unaligned (attr->cu->dbg, attr->valp);
     72       break;
     73 
     74     case DW_FORM_ref8:
     75       if (datap + 8 > endp)
     76 	goto invalid;
     77       *return_offset = read_8ubyte_unaligned (attr->cu->dbg, attr->valp);
     78       break;
     79 
     80     case DW_FORM_ref_udata:
     81       if (datap + 1 > endp)
     82 	goto invalid;
     83       get_uleb128 (*return_offset, datap, endp);
     84       break;
     85 
     86     case DW_FORM_ref_addr:
     87     case DW_FORM_ref_sig8:
     88     case DW_FORM_GNU_ref_alt:
     89       /* These aren't handled by dwarf_formref, only by dwarf_formref_die.  */
     90       __libdw_seterrno (DWARF_E_INVALID_REFERENCE);
     91       return -1;
     92 
     93     default:
     94       __libdw_seterrno (DWARF_E_NO_REFERENCE);
     95       return -1;
     96     }
     97 
     98   return 0;
     99 }
    100 
    101 /* This is the old public entry point.
    102    It is now deprecated in favor of dwarf_formref_die.  */
    103 int
    104 dwarf_formref (Dwarf_Attribute *attr, Dwarf_Off *return_offset)
    105 {
    106   if (attr == NULL)
    107     return -1;
    108 
    109   return __libdw_formref (attr, return_offset);
    110 }
    111