Line data    Source code

       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         296 : elfw2(LIBELFBITS,offscn) (Elf *elf, ElfW2(LIBELFBITS,Off) offset)
      47             : {
      48         296 :   if (elf == NULL)
      49             :     return NULL;
      50             : 
      51         296 :   if (unlikely (elf->kind != ELF_K_ELF))
      52             :     {
      53           0 :       __libelf_seterrno (ELF_E_INVALID_HANDLE);
      54           0 :       return NULL;
      55             :     }
      56             : 
      57         296 :   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         296 :   if (runp->cnt > 0
      62         296 :       && unlikely (runp->data[0].shdr.ELFW(e,LIBELFBITS) == NULL)
      63           1 :       && unlikely (elfw2(LIBELFBITS,getshdr) (&runp->data[0]) == NULL))
      64             :     return NULL;
      65             : 
      66             :   rwlock_rdlock (elf->lock);
      67             : 
      68         296 :   Elf_Scn *result = NULL;
      69             : 
      70             :   /* Find the section in the list.  */
      71             :   while (1)
      72             :     {
      73        6299 :       for (unsigned int i = 0; i < runp->cnt; ++i)
      74        6299 :         if (runp->data[i].shdr.ELFW(e,LIBELFBITS)->sh_offset == offset)
      75             :           {
      76         301 :             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         301 :             if (runp->data[i].shdr.ELFW(e,LIBELFBITS)->sh_size != 0
      82         301 :                 && runp->data[i].shdr.ELFW(e,LIBELFBITS)->sh_type != SHT_NOBITS)
      83             :               goto out;
      84             :           }
      85             : 
      86           0 :       runp = runp->next;
      87           0 :       if (runp == NULL)
      88             :         {
      89           0 :           __libelf_seterrno (ELF_E_INVALID_OFFSET);
      90           0 :           break;
      91             :         }
      92             :     }
      93             : 
      94         296 :  out:
      95             :   rwlock_unlock (elf->lock);
      96             : 
      97             :   return result;
      98             : }
      99             : INTDEF(elfw2(LIBELFBITS,offscn))