Line data    Source code

       1             : /* Get symbol information from symbol table at the given index.
       2             :    Copyright (C) 1999, 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>, 1999.
       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_Sym *
      42       59639 : gelf_getsym (Elf_Data *data, int ndx, GElf_Sym *dst)
      43             : {
      44       59639 :   Elf_Data_Scn *data_scn = (Elf_Data_Scn *) data;
      45       59639 :   GElf_Sym *result = NULL;
      46             : 
      47       59639 :   if (data == NULL)
      48             :     return NULL;
      49             : 
      50       59639 :   if (unlikely (data->d_type != ELF_T_SYM))
      51             :     {
      52           0 :       __libelf_seterrno (ELF_E_INVALID_HANDLE);
      53           0 :       return NULL;
      54             :     }
      55             : 
      56       59639 :   rwlock_rdlock (data_scn->s->elf->lock);
      57             : 
      58             :   /* This is the one place where we have to take advantage of the fact
      59             :      that an `Elf_Data' pointer is also a pointer to `Elf_Data_Scn'.
      60             :      The interface is broken so that it requires this hack.  */
      61       59639 :   if (data_scn->s->elf->class == ELFCLASS32)
      62             :     {
      63             :       Elf32_Sym *src;
      64             : 
      65             :       /* Here it gets a bit more complicated.  The format of the symbol
      66             :          table entries has to be adopted.  The user better has provided
      67             :          a buffer where we can store the information.  While copying the
      68             :          data we are converting the format.  */
      69       31358 :       if (INVALID_NDX (ndx, Elf32_Sym, data))
      70             :         {
      71           0 :           __libelf_seterrno (ELF_E_INVALID_INDEX);
      72           0 :           goto out;
      73             :         }
      74             : 
      75       31358 :       src = &((Elf32_Sym *) data->d_buf)[ndx];
      76             : 
      77             :       /* This might look like a simple copy operation but it's
      78             :          not.  There are zero- and sign-extensions going on.  */
      79             : #define COPY(name) \
      80             :       dst->name = src->name
      81       31358 :       COPY (st_name);
      82             :       /* Please note that we can simply copy the `st_info' element since
      83             :          the definitions of ELFxx_ST_BIND and ELFxx_ST_TYPE are the same
      84             :          for the 64 bit variant.  */
      85       31358 :       COPY (st_info);
      86       31358 :       COPY (st_other);
      87       31358 :       COPY (st_shndx);
      88       31358 :       COPY (st_value);
      89       31358 :       COPY (st_size);
      90             :     }
      91             :   else
      92             :     {
      93             :       /* If this is a 64 bit object it's easy.  */
      94             :       assert (sizeof (GElf_Sym) == sizeof (Elf64_Sym));
      95             : 
      96             :       /* The data is already in the correct form.  Just make sure the
      97             :          index is OK.  */
      98       28281 :       if (INVALID_NDX (ndx, GElf_Sym, data))
      99             :         {
     100           0 :           __libelf_seterrno (ELF_E_INVALID_INDEX);
     101           0 :           goto out;
     102             :         }
     103             : 
     104       28281 :       *dst = ((GElf_Sym *) data->d_buf)[ndx];
     105             :     }
     106             : 
     107             :   result = dst;
     108             : 
     109             :  out:
     110             :   rwlock_unlock (data_scn->s->elf->lock);
     111             : 
     112       59639 :   return result;
     113             : }
     114             : INTDEF(gelf_getsym)