Branch data     Line data    Source code

       1                 :            : /* Get symbol information and separate section index from symbol table
       2                 :            :    at the given index.
       3                 :            :    Copyright (C) 2000, 2001, 2002, 2005, 2009, 2014, 2015 Red Hat, Inc.
       4                 :            :    This file is part of elfutils.
       5                 :            :    Written by Ulrich Drepper <drepper@redhat.com>, 2000.
       6                 :            : 
       7                 :            :    This file is free software; you can redistribute it and/or modify
       8                 :            :    it under the terms of either
       9                 :            : 
      10                 :            :      * the GNU Lesser General Public License as published by the Free
      11                 :            :        Software Foundation; either version 3 of the License, or (at
      12                 :            :        your option) any later version
      13                 :            : 
      14                 :            :    or
      15                 :            : 
      16                 :            :      * the GNU General Public License as published by the Free
      17                 :            :        Software Foundation; either version 2 of the License, or (at
      18                 :            :        your option) any later version
      19                 :            : 
      20                 :            :    or both in parallel, as here.
      21                 :            : 
      22                 :            :    elfutils is distributed in the hope that it will be useful, but
      23                 :            :    WITHOUT ANY WARRANTY; without even the implied warranty of
      24                 :            :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      25                 :            :    General Public License for more details.
      26                 :            : 
      27                 :            :    You should have received copies of the GNU General Public License and
      28                 :            :    the GNU Lesser General Public License along with this program.  If
      29                 :            :    not, see <http://www.gnu.org/licenses/>.  */
      30                 :            : 
      31                 :            : #ifdef HAVE_CONFIG_H
      32                 :            : # include <config.h>
      33                 :            : #endif
      34                 :            : 
      35                 :            : #include <assert.h>
      36                 :            : #include <gelf.h>
      37                 :            : #include <string.h>
      38                 :            : 
      39                 :            : #include "libelfP.h"
      40                 :            : 
      41                 :            : 
      42                 :            : GElf_Sym *
      43                 :   17379117 : gelf_getsymshndx (Elf_Data *symdata, Elf_Data *shndxdata, int ndx,
      44                 :            :                   GElf_Sym *dst, Elf32_Word *dstshndx)
      45                 :            : {
      46                 :   17379117 :   Elf_Data_Scn *symdata_scn = (Elf_Data_Scn *) symdata;
      47                 :   17379117 :   Elf_Data_Scn *shndxdata_scn = (Elf_Data_Scn *) shndxdata;
      48                 :   17379117 :   GElf_Sym *result = NULL;
      49                 :   17379117 :   Elf32_Word shndx = 0;
      50                 :            : 
      51         [ -  + ]:   17379117 :   if (symdata == NULL)
      52                 :            :     return NULL;
      53                 :            : 
      54         [ +  - ]:   17379117 :   if (unlikely (symdata->d_type != ELF_T_SYM)
      55         [ +  + ]:   17379117 :       || (likely (shndxdata_scn != NULL)
      56         [ -  + ]:      88002 :           && unlikely (shndxdata->d_type != ELF_T_WORD)))
      57                 :            :     {
      58                 :          0 :       __libelf_seterrno (ELF_E_INVALID_HANDLE);
      59                 :          0 :       return NULL;
      60                 :            :     }
      61                 :            : 
      62                 :   17379117 :   rwlock_rdlock (symdata_scn->s->elf->lock);
      63                 :            : 
      64                 :            :   /* The user is not required to pass a data descriptor for an extended
      65                 :            :      section index table.  */
      66         [ +  + ]:   17379117 :   if (likely (shndxdata_scn != NULL))
      67                 :            :     {
      68         [ -  + ]:      88002 :       if (INVALID_NDX (ndx, Elf32_Word, &shndxdata_scn->d))
      69                 :            :         {
      70                 :          0 :           __libelf_seterrno (ELF_E_INVALID_INDEX);
      71                 :          0 :           goto out;
      72                 :            :         }
      73                 :            : 
      74                 :      88002 :       shndx = ((Elf32_Word *) shndxdata_scn->d.d_buf)[ndx];
      75                 :            :     }
      76                 :            : 
      77                 :            :   /* This is the one place where we have to take advantage of the fact
      78                 :            :      that an `Elf_Data' pointer is also a pointer to `Elf_Data_Scn'.
      79                 :            :      The interface is broken so that it requires this hack.  */
      80         [ +  + ]:   17379117 :   if (symdata_scn->s->elf->class == ELFCLASS32)
      81                 :            :     {
      82                 :     301491 :       Elf32_Sym *src;
      83                 :            : 
      84                 :            :       /* Here it gets a bit more complicated.  The format of the symbol
      85                 :            :          table entries has to be adopted.  The user better has provided
      86                 :            :          a buffer where we can store the information.  While copying the
      87                 :            :          data we are converting the format.  */
      88         [ -  + ]:     301491 :       if (INVALID_NDX (ndx, Elf32_Sym, symdata))
      89                 :            :         {
      90                 :          0 :           __libelf_seterrno (ELF_E_INVALID_INDEX);
      91                 :          0 :           goto out;
      92                 :            :         }
      93                 :            : 
      94                 :     301491 :       src = &((Elf32_Sym *) symdata->d_buf)[ndx];
      95                 :            : 
      96                 :            :       /* This might look like a simple copy operation but it's
      97                 :            :          not.  There are zero- and sign-extensions going on.  */
      98                 :            : #define COPY(name) \
      99                 :            :       dst->name = src->name
     100                 :     301491 :       COPY (st_name);
     101                 :            :       /* Please note that we can simply copy the `st_info' element since
     102                 :            :          the definitions of ELFxx_ST_BIND and ELFxx_ST_TYPE are the same
     103                 :            :          for the 64 bit variant.  */
     104                 :     301491 :       COPY (st_info);
     105                 :     301491 :       COPY (st_other);
     106                 :     301491 :       COPY (st_shndx);
     107                 :     301491 :       COPY (st_value);
     108                 :     301491 :       COPY (st_size);
     109                 :            :     }
     110                 :            :   else
     111                 :            :     {
     112                 :            :       /* If this is a 64 bit object it's easy.  */
     113                 :   17077626 :       assert (sizeof (GElf_Sym) == sizeof (Elf64_Sym));
     114                 :            : 
     115                 :            :       /* The data is already in the correct form.  Just make sure the
     116                 :            :          index is OK.  */
     117         [ -  + ]:   17077626 :       if (INVALID_NDX (ndx, GElf_Sym, symdata))
     118                 :            :         {
     119                 :          0 :           __libelf_seterrno (ELF_E_INVALID_INDEX);
     120                 :          0 :           goto out;
     121                 :            :         }
     122                 :            : 
     123                 :   17077626 :       *dst = ((GElf_Sym *) symdata->d_buf)[ndx];
     124                 :            :     }
     125                 :            : 
     126                 :            :   /* Now we can store the section index.  */
     127         [ +  - ]:   17379117 :   if (dstshndx != NULL)
     128                 :   17379117 :     *dstshndx = shndx;
     129                 :            : 
     130                 :            :   result = dst;
     131                 :            : 
     132                 :   17379117 :  out:
     133                 :   17379117 :   rwlock_unlock (symdata_scn->s->elf->lock);
     134                 :            : 
     135                 :   17379117 :   return result;
     136                 :            : }