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       1                 :            : /* Get information from dynamic table at the given index.
       2                 :            :    Copyright (C) 2000, 2001, 2002, 2005, 2009, 2014, 2015 Red Hat, Inc.
       3                 :            :    This file is part of elfutils.
       4                 :            :    Written by Ulrich Drepper <drepper@redhat.com>, 2000.
       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 <assert.h>
      35                 :            : #include <gelf.h>
      36                 :            : #include <string.h>
      37                 :            : 
      38                 :            : #include "libelfP.h"
      39                 :            : 
      40                 :            : 
      41                 :            : GElf_Dyn *
      42                 :      18116 : gelf_getdyn (Elf_Data *data, int ndx, GElf_Dyn *dst)
      43                 :            : {
      44                 :      18116 :   Elf_Data_Scn *data_scn = (Elf_Data_Scn *) data;
      45                 :      18116 :   GElf_Dyn *result = NULL;
      46                 :      18116 :   Elf *elf;
      47                 :            : 
      48         [ -  + ]:      18116 :   if (data_scn == NULL)
      49                 :            :     return NULL;
      50                 :            : 
      51         [ -  + ]:      18116 :   if (unlikely (data_scn->d.d_type != ELF_T_DYN))
      52                 :            :     {
      53                 :          0 :       __libelf_seterrno (ELF_E_INVALID_HANDLE);
      54                 :          0 :       return NULL;
      55                 :            :     }
      56                 :            : 
      57                 :      18116 :   elf = data_scn->s->elf;
      58                 :            : 
      59                 :      18116 :   rwlock_rdlock (elf->lock);
      60                 :            : 
      61                 :            :   /* This is the one place where we have to take advantage of the fact
      62                 :            :      that an `Elf_Data' pointer is also a pointer to `Elf_Data_Scn'.
      63                 :            :      The interface is broken so that it requires this hack.  */
      64         [ +  + ]:      18116 :   if (elf->class == ELFCLASS32)
      65                 :            :     {
      66                 :       4578 :       Elf32_Dyn *src;
      67                 :            : 
      68                 :            :       /* Here it gets a bit more complicated.  The format of the symbol
      69                 :            :          table entries has to be adopted.  The user better has provided
      70                 :            :          a buffer where we can store the information.  While copying the
      71                 :            :          data we are converting the format.  */
      72         [ +  + ]:       4578 :       if (INVALID_NDX (ndx, Elf32_Dyn, &data_scn->d))
      73                 :            :         {
      74                 :         24 :           __libelf_seterrno (ELF_E_INVALID_INDEX);
      75                 :         24 :           goto out;
      76                 :            :         }
      77                 :            : 
      78                 :       4554 :       src = &((Elf32_Dyn *) data_scn->d.d_buf)[ndx];
      79                 :            : 
      80                 :            :       /* This might look like a simple copy operation but it's
      81                 :            :          not.  There are zero- and sign-extensions going on.  */
      82                 :       4554 :       dst->d_tag = src->d_tag;
      83                 :            :       /* It OK to copy `d_val' since `d_ptr' has the same size.  */
      84                 :       4554 :       dst->d_un.d_val = src->d_un.d_val;
      85                 :            :     }
      86                 :            :   else
      87                 :            :     {
      88                 :            :       /* If this is a 64 bit object it's easy.  */
      89                 :      13538 :       assert (sizeof (GElf_Dyn) == sizeof (Elf64_Dyn));
      90                 :            : 
      91                 :            :       /* The data is already in the correct form.  Just make sure the
      92                 :            :          index is OK.  */
      93         [ +  + ]:      13538 :       if (INVALID_NDX (ndx, GElf_Dyn, &data_scn->d))
      94                 :            :         {
      95                 :         28 :           __libelf_seterrno (ELF_E_INVALID_INDEX);
      96                 :         28 :           goto out;
      97                 :            :         }
      98                 :            : 
      99                 :      13510 :       *dst = ((GElf_Dyn *) data_scn->d.d_buf)[ndx];
     100                 :            :     }
     101                 :            : 
     102                 :            :   result = dst;
     103                 :            : 
     104                 :            :  out:
     105                 :            :   rwlock_unlock (elf->lock);
     106                 :            : 
     107                 :            :   return result;
     108                 :            : }