LCOV - code coverage report
Current view: top level - libdw - dwarf_child.c (source / functions) Hit Total Coverage
Test: elfutils-0.175 Lines: 47 50 94.0 %
Date: 2018-11-16 13:02:39 Functions: 2 2 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /* Return child of current DIE.
       2             :    Copyright (C) 2003-2011, 2014, 2017 Red Hat, Inc.
       3             :    This file is part of elfutils.
       4             :    Written by Ulrich Drepper <drepper@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 "libdwP.h"
      35             : #include <string.h>
      36             : 
      37             : /* Some arbitrary value not conflicting with any existing code.  */
      38             : #define INVALID 0xffffe444
      39             : 
      40             : 
      41             : unsigned char *
      42             : internal_function
      43    42448396 : __libdw_find_attr (Dwarf_Die *die, unsigned int search_name,
      44             :                    unsigned int *codep, unsigned int *formp)
      45             : {
      46             :   const unsigned char *readp;
      47             : 
      48             :   /* Find the abbreviation entry.  */
      49    42448396 :   Dwarf_Abbrev *abbrevp = __libdw_dieabbrev (die, &readp);
      50    42448396 :   if (unlikely (abbrevp == DWARF_END_ABBREV))
      51             :     {
      52        4415 :       __libdw_seterrno (DWARF_E_INVALID_DWARF);
      53        4415 :       return NULL;
      54             :     }
      55             : 
      56             :   /* Search the name attribute.  Attribute has been checked when
      57             :      Dwarf_Abbrev was created, we can read unchecked.  */
      58    42443981 :   const unsigned char *attrp = abbrevp->attrp;
      59             :   while (1)
      60             :     {
      61             :       /* Get attribute name and form.  */
      62             :       unsigned int attr_name;
      63   170841552 :       get_uleb128_unchecked (attr_name, attrp);
      64             : 
      65             :       unsigned int attr_form;
      66   170841552 :       get_uleb128_unchecked (attr_form, attrp);
      67             : 
      68             :       /* We can stop if we found the attribute with value zero.  */
      69   170841552 :       if (attr_name == 0 && attr_form == 0)
      70             :         break;
      71             : 
      72             :       /* Is this the name attribute?  */
      73   135505313 :       if (attr_name == search_name && search_name != INVALID)
      74             :         {
      75     7107742 :           if (codep != NULL)
      76     7107742 :             *codep = attr_name;
      77     7107742 :           if (formp != NULL)
      78     7107742 :             *formp = attr_form;
      79             : 
      80             :           /* Normally the attribute data comes from the DIE/info,
      81             :              except for implicit_form, where it comes from the abbrev.  */
      82     7107742 :           if (attr_form == DW_FORM_implicit_const)
      83           0 :             return (unsigned char *) attrp;
      84             :           else
      85     7107742 :             return (unsigned char *) readp;
      86             :         }
      87             : 
      88             :       /* Skip over the rest of this attribute (if there is any).  */
      89   128397571 :       if (attr_form != 0)
      90             :         {
      91   128397571 :           size_t len = __libdw_form_val_len (die->cu, attr_form, readp);
      92   128397571 :           if (unlikely (len == (size_t) -1l))
      93             :             {
      94           0 :               readp = NULL;
      95           0 :               break;
      96             :             }
      97             : 
      98             :           // __libdw_form_val_len will have done a bounds check.
      99   128397571 :           readp += len;
     100             : 
     101             :           // If the value is in the abbrev data, skip it.
     102   128397571 :           if (attr_form == DW_FORM_implicit_const)
     103             :             {
     104             :               int64_t attr_value __attribute__((__unused__));
     105         913 :               get_sleb128_unchecked (attr_value, attrp);
     106             :             }
     107             :         }
     108             :     }
     109             : 
     110             :   // XXX Do we need other values?
     111    35336239 :   if (codep != NULL)
     112    30959239 :     *codep = INVALID;
     113    35336239 :   if (formp != NULL)
     114    30959239 :     *formp = INVALID;
     115             : 
     116    35336239 :   return (unsigned char *) readp;
     117             : }
     118             : 
     119             : 
     120             : int
     121     5460536 : dwarf_child (Dwarf_Die *die, Dwarf_Die *result)
     122             : {
     123             :   /* Ignore previous errors.  */
     124     5460536 :   if (die == NULL)
     125             :     return -1;
     126             : 
     127             :   /* Find the abbreviation entry.  */
     128     5460536 :   Dwarf_Abbrev *abbrevp = __libdw_dieabbrev (die, NULL);
     129     5460536 :   if (unlikely (abbrevp == DWARF_END_ABBREV))
     130             :     {
     131         883 :       __libdw_seterrno (DWARF_E_INVALID_DWARF);
     132         883 :       return -1;
     133             :     }
     134             : 
     135             :   /* If there are no children, do not search.  */
     136     5459653 :   if (! abbrevp->has_children)
     137             :     return 1;
     138             : 
     139             :   /* Skip past the last attribute.  */
     140     4377000 :   void *addr = __libdw_find_attr (die, INVALID, NULL, NULL);
     141             : 
     142     4377000 :   if (addr == NULL)
     143             :     return -1;
     144             : 
     145             :   /* RESULT can be the same as DIE.  So preserve what we need.  */
     146     4377000 :   struct Dwarf_CU *cu = die->cu;
     147             : 
     148             :   /* It's kosher (just suboptimal) to have a null entry first thing (7.5.3).
     149             :      So if this starts with ULEB128 of 0 (even with silly encoding of 0),
     150             :      it is a kosher null entry and we do not really have any children.  */
     151     4377000 :   const unsigned char *code = addr;
     152     4377000 :   const unsigned char *endp = cu->endp;
     153             :   while (1)
     154             :     {
     155     4377004 :       if (unlikely (code >= endp)) /* Truncated section.  */
     156             :         return 1;
     157     4377002 :       if (unlikely (*code == 0x80))
     158           2 :         ++code;
     159             :       else
     160             :         break;
     161             :     }
     162     4377000 :   if (unlikely (*code == '\0'))
     163             :     return 1;
     164             : 
     165             :   /* Clear the entire DIE structure.  This signals we have not yet
     166             :      determined any of the information.  */
     167     4377000 :   memset (result, '\0', sizeof (Dwarf_Die));
     168             : 
     169             :   /* We have the address.  */
     170     4377000 :   result->addr = addr;
     171             : 
     172             :   /* Same CU as the parent.  */
     173     4377000 :   result->cu = cu;
     174             : 
     175     4377000 :   return 0;
     176             : }
     177             : INTDEF(dwarf_child)

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