Line data    Source code

       1             : /* Get attributes of the DIE.
       2             :    Copyright (C) 2004, 2005, 2008, 2009, 2014, 2017 Red Hat, Inc.
       3             :    This file is part of elfutils.
       4             :    Written by Ulrich Drepper <drepper@redhat.com>, 2004.
       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 "libdwP.h"
      35             : 
      36             : 
      37             : ptrdiff_t
      38     1256423 : dwarf_getattrs (Dwarf_Die *die, int (*callback) (Dwarf_Attribute *, void *),
      39             :                 void *arg, ptrdiff_t offset)
      40             : {
      41     1256423 :   if (die == NULL)
      42             :     return -1l;
      43             : 
      44     1256423 :   if (unlikely (offset == 1))
      45             :     return 1;
      46             : 
      47     1256423 :   const unsigned char *die_addr = NULL;
      48             : 
      49             :   /* Find the abbreviation entry.  */
      50     1256423 :   Dwarf_Abbrev *abbrevp = __libdw_dieabbrev (die, &die_addr);
      51             : 
      52     1256423 :   if (unlikely (abbrevp == DWARF_END_ABBREV))
      53             :     {
      54           0 :       __libdw_seterrno (DWARF_E_INVALID_DWARF);
      55           0 :       return -1l;
      56             :     }
      57             : 
      58             :   /* This is where the attributes start.  */
      59     1256423 :   const unsigned char *attrp = abbrevp->attrp;
      60     1256423 :   const unsigned char *const offset_attrp = abbrevp->attrp + offset;
      61             : 
      62             :   /* Go over the list of attributes.  */
      63             :   while (1)
      64     4348984 :     {
      65             :       /* Get attribute name and form.  Dwarf_Abbrev was checked when
      66             :          created, so we can read unchecked.  */
      67             :       Dwarf_Attribute attr;
      68     5605407 :       const unsigned char *remembered_attrp = attrp;
      69             : 
      70     5605407 :       get_uleb128_unchecked (attr.code, attrp);
      71     5605407 :       get_uleb128_unchecked (attr.form, attrp);
      72             : 
      73             :       /* We can stop if we found the attribute with value zero.  */
      74     5605407 :       if (attr.code == 0 && attr.form == 0)
      75             :         /* Do not return 0 here - there would be no way to
      76             :            distinguish this value from the attribute at offset 0.
      77             :            Instead we return +1 which would never be a valid
      78             :            offset of an attribute.  */
      79     1256423 :         return 1l;
      80             : 
      81             :       /* If we are not to OFFSET_ATTRP yet, we just have to skip
      82             :          the values of the intervening attributes.  */
      83     4348984 :       if (remembered_attrp >= offset_attrp)
      84             :         {
      85             :           /* Fill in the rest.  */
      86     4348984 :           if (attr.form == DW_FORM_implicit_const)
      87         105 :             attr.valp = (unsigned char *) attrp;
      88             :           else
      89     4348879 :             attr.valp = (unsigned char *) die_addr;
      90     4348984 :           attr.cu = die->cu;
      91             : 
      92             :           /* Now call the callback function.  */
      93     4348984 :           if (callback (&attr, arg) != DWARF_CB_OK)
      94             :             /* Return the offset of the start of the attribute, so that
      95             :                dwarf_getattrs() can be restarted from this point if the
      96             :                caller so desires.  */
      97           0 :             return remembered_attrp - abbrevp->attrp;
      98             :         }
      99             : 
     100             :       /* Skip over the rest of this attribute (if there is any).  */
     101     4348984 :       if (attr.form != 0)
     102             :         {
     103     4348984 :           size_t len = __libdw_form_val_len (die->cu, attr.form, die_addr);
     104     4348984 :           if (unlikely (len == (size_t) -1l))
     105             :             /* Something wrong with the file.  */
     106             :             return -1l;
     107             : 
     108             :           // __libdw_form_val_len will have done a bounds check.
     109     4348984 :           die_addr += len;
     110             : 
     111     4348984 :           if (attr.form == DW_FORM_implicit_const)
     112             :             {
     113             :               int64_t attr_value __attribute__((__unused__));
     114         105 :               get_sleb128_unchecked (attr_value, attrp);
     115             :             }
     116             :         }
     117             :     }
     118             :   /* NOTREACHED */
     119             : }