Blame libelf/gelf_update_symshndx.c

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/* Update symbol information and section index in symbol table at the
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   given index.
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   Copyright (C) 2000, 2001, 2002, 2005, 2009, 2014, 2015 Red Hat, Inc.
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   This file is part of elfutils.
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   Written by Ulrich Drepper <drepper@redhat.com>, 2000.
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   This file is free software; you can redistribute it and/or modify
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   it under the terms of either
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     * the GNU Lesser General Public License as published by the Free
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       Software Foundation; either version 3 of the License, or (at
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       your option) any later version
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   or
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     * the GNU General Public License as published by the Free
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       Software Foundation; either version 2 of the License, or (at
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       your option) any later version
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   or both in parallel, as here.
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   elfutils is distributed in the hope that it will be useful, but
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   WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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   General Public License for more details.
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   You should have received copies of the GNU General Public License and
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   the GNU Lesser General Public License along with this program.  If
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   not, see <http://www.gnu.org/licenses/>.  */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <gelf.h>
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#include <stdlib.h>
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#include <string.h>
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#include "libelfP.h"
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int
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gelf_update_symshndx (Elf_Data *symdata, Elf_Data *shndxdata, int ndx,
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		      GElf_Sym *src, Elf32_Word srcshndx)
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{
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  Elf_Data_Scn *symdata_scn = (Elf_Data_Scn *) symdata;
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  Elf_Data_Scn *shndxdata_scn = (Elf_Data_Scn *) shndxdata;
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  Elf_Scn *scn;
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  Elf32_Word *shndx = NULL;
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  int result = 0;
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  if (symdata == NULL)
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    return 0;
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  if (unlikely (symdata_scn->d.d_type != ELF_T_SYM))
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    {
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      /* The type of the data better should match.  */
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      __libelf_seterrno (ELF_E_DATA_MISMATCH);
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      return 0;
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    }
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  scn = symdata_scn->s;
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  /* We simply have to believe the user that the two sections belong to
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     the same ELF file.  */
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  rwlock_wrlock (scn->elf->lock);
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  /* The user is not required to pass a data descriptor for an extended
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     section index table.  */
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  if (shndxdata_scn != NULL)
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    {
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      if (unlikely ((ndx + 1) * sizeof (Elf32_Word) > shndxdata_scn->d.d_size))
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	{
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	  __libelf_seterrno (ELF_E_INVALID_INDEX);
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	  goto out;
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	}
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      shndx = &((Elf32_Word *) shndxdata_scn->d.d_buf)[ndx];
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    }
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  /* But if s/he does not the extended sectio index must be zero.  */
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  else if (unlikely (srcshndx != 0))
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    {
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      __libelf_seterrno (ELF_E_INVALID_INDEX);
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      goto out;
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    }
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  if (scn->elf->class == ELFCLASS32)
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    {
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      Elf32_Sym *sym;
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      /* There is the possibility that the values in the input are
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	 too large.  */
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      if (unlikely (src->st_value > 0xffffffffull)
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	  || unlikely (src->st_size > 0xffffffffull))
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	{
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	  __libelf_seterrno (ELF_E_INVALID_DATA);
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	  goto out;
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	}
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      /* Check whether we have to resize the data buffer.  */
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      if (INVALID_NDX (ndx, Elf32_Sym, &symdata_scn->d))
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	{
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	  __libelf_seterrno (ELF_E_INVALID_INDEX);
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	  goto out;
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	}
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      sym = &((Elf32_Sym *) symdata_scn->d.d_buf)[ndx];
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#define COPY(name) \
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      sym->name = src->name
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      COPY (st_name);
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      COPY (st_value);
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      COPY (st_size);
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      /* Please note that we can simply copy the `st_info' element since
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	 the definitions of ELFxx_ST_BIND and ELFxx_ST_TYPE are the same
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	 for the 64 bit variant.  */
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      COPY (st_info);
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      COPY (st_other);
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      COPY (st_shndx);
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    }
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  else
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    {
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      /* Check whether we have to resize the data buffer.  */
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      if (INVALID_NDX (ndx, Elf64_Sym, &symdata_scn->d))
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	{
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	  __libelf_seterrno (ELF_E_INVALID_INDEX);
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	  goto out;
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	}
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      ((Elf64_Sym *) symdata_scn->d.d_buf)[ndx] = *src;
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    }
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  /* Now we can store the section index.  */
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  if (shndx != NULL)
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    *shndx = srcshndx;
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  result = 1;
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  /* Mark the section as modified.  */
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  scn->flags |= ELF_F_DIRTY;
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 out:
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  rwlock_unlock (scn->elf->lock);
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  return result;
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}