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       1                 :            : /* Get section at specific index.
       2                 :            :    Copyright (C) 2005, 2008, 2015 Red Hat, Inc.
       3                 :            :    This file is part of elfutils.
       4                 :            :    Contributed by Ulrich Drepper <drepper@redhat.com>, 2005.
       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 <stddef.h>
      36                 :            : #include <stdlib.h>
      37                 :            : 
      38                 :            : #include "libelfP.h"
      39                 :            : 
      40                 :            : #ifndef LIBELFBITS
      41                 :            : # define LIBELFBITS 32
      42                 :            : #endif
      43                 :            : 
      44                 :            : 
      45                 :            : Elf_Scn *
      46                 :       1178 : elfw2(LIBELFBITS,offscn) (Elf *elf, ElfW2(LIBELFBITS,Off) offset)
      47                 :            : {
      48         [ -  + ]:       1178 :   if (elf == NULL)
      49                 :            :     return NULL;
      50                 :            : 
      51         [ -  + ]:       1178 :   if (unlikely (elf->kind != ELF_K_ELF))
      52                 :            :     {
      53                 :          0 :       __libelf_seterrno (ELF_E_INVALID_HANDLE);
      54                 :          0 :       return NULL;
      55                 :            :     }
      56                 :            : 
      57                 :       1178 :   Elf_ScnList *runp = &elf->state.ELFW(elf,LIBELFBITS).scns;
      58                 :            : 
      59                 :            :   /* If we have not looked at section headers before,
      60                 :            :      we might need to read them in first.  */
      61         [ +  - ]:       1178 :   if (runp->cnt > 0
      62         [ +  + ]:       1178 :       && unlikely (runp->data[0].shdr.ELFW(e,LIBELFBITS) == NULL)
      63         [ -  + ]:          2 :       && unlikely (elfw2(LIBELFBITS,getshdr) (&runp->data[0]) == NULL))
      64                 :            :     return NULL;
      65                 :            : 
      66                 :       1178 :   rwlock_rdlock (elf->lock);
      67                 :            : 
      68                 :       1178 :   Elf_Scn *result = NULL;
      69                 :            : 
      70                 :            :   /* Find the section in the list.  */
      71                 :       1178 :   while (1)
      72                 :            :     {
      73         [ +  + ]:      23224 :       for (unsigned int i = 0; i < runp->cnt; ++i)
      74         [ +  + ]:      23164 :         if (runp->data[i].shdr.ELFW(e,LIBELFBITS)->sh_offset == offset)
      75                 :            :           {
      76                 :       1220 :             result = &runp->data[i];
      77                 :            : 
      78                 :            :             /* If this section is empty, the following one has the same
      79                 :            :                sh_offset.  We presume the caller is looking for a nonempty
      80                 :            :                section, so keep looking if this one is empty.  */
      81         [ +  - ]:       1220 :             if (runp->data[i].shdr.ELFW(e,LIBELFBITS)->sh_size != 0
      82         [ +  + ]:       1220 :                 && runp->data[i].shdr.ELFW(e,LIBELFBITS)->sh_type != SHT_NOBITS)
      83                 :       1118 :               goto out;
      84                 :            :           }
      85                 :            : 
      86                 :         60 :       runp = runp->next;
      87         [ -  + ]:         60 :       if (runp == NULL)
      88                 :            :         {
      89                 :         60 :           __libelf_seterrno (ELF_E_INVALID_OFFSET);
      90                 :         60 :           break;
      91                 :            :         }
      92                 :            :     }
      93                 :            : 
      94                 :            :  out:
      95                 :            :   rwlock_unlock (elf->lock);
      96                 :            : 
      97                 :            :   return result;
      98                 :            : }
      99                 :            : INTDEF(elfw2(LIBELFBITS,offscn))