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      1 /* Update symbol information and section index in symbol table at the
      2    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 (at) 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 <gelf.h>
     36 #include <stdlib.h>
     37 #include <string.h>
     38 
     39 #include "libelfP.h"
     40 
     41 
     42 int
     43 gelf_update_symshndx (Elf_Data *symdata, Elf_Data *shndxdata, int ndx,
     44 		      GElf_Sym *src, Elf32_Word srcshndx)
     45 {
     46   Elf_Data_Scn *symdata_scn = (Elf_Data_Scn *) symdata;
     47   Elf_Data_Scn *shndxdata_scn = (Elf_Data_Scn *) shndxdata;
     48   Elf_Scn *scn;
     49   Elf32_Word *shndx = NULL;
     50   int result = 0;
     51 
     52   if (symdata == NULL)
     53     return 0;
     54 
     55   if (unlikely (symdata_scn->d.d_type != ELF_T_SYM))
     56     {
     57       /* The type of the data better should match.  */
     58       __libelf_seterrno (ELF_E_DATA_MISMATCH);
     59       return 0;
     60     }
     61 
     62   scn = symdata_scn->s;
     63   /* We simply have to believe the user that the two sections belong to
     64      the same ELF file.  */
     65   rwlock_wrlock (scn->elf->lock);
     66 
     67   /* The user is not required to pass a data descriptor for an extended
     68      section index table.  */
     69   if (shndxdata_scn != NULL)
     70     {
     71       if (unlikely ((ndx + 1) * sizeof (Elf32_Word) > shndxdata_scn->d.d_size))
     72 	{
     73 	  __libelf_seterrno (ELF_E_INVALID_INDEX);
     74 	  goto out;
     75 	}
     76 
     77       shndx = &((Elf32_Word *) shndxdata_scn->d.d_buf)[ndx];
     78     }
     79   /* But if s/he does not the extended sectio index must be zero.  */
     80   else if (unlikely (srcshndx != 0))
     81     {
     82       __libelf_seterrno (ELF_E_INVALID_INDEX);
     83       goto out;
     84     }
     85 
     86   if (scn->elf->class == ELFCLASS32)
     87     {
     88       Elf32_Sym *sym;
     89 
     90       /* There is the possibility that the values in the input are
     91 	 too large.  */
     92       if (unlikely (src->st_value > 0xffffffffull)
     93 	  || unlikely (src->st_size > 0xffffffffull))
     94 	{
     95 	  __libelf_seterrno (ELF_E_INVALID_DATA);
     96 	  goto out;
     97 	}
     98 
     99       /* Check whether we have to resize the data buffer.  */
    100       if (INVALID_NDX (ndx, Elf32_Sym, &symdata_scn->d))
    101 	{
    102 	  __libelf_seterrno (ELF_E_INVALID_INDEX);
    103 	  goto out;
    104 	}
    105 
    106       sym = &((Elf32_Sym *) symdata_scn->d.d_buf)[ndx];
    107 
    108 #define COPY(name) \
    109       sym->name = src->name
    110       COPY (st_name);
    111       COPY (st_value);
    112       COPY (st_size);
    113       /* Please note that we can simply copy the `st_info' element since
    114 	 the definitions of ELFxx_ST_BIND and ELFxx_ST_TYPE are the same
    115 	 for the 64 bit variant.  */
    116       COPY (st_info);
    117       COPY (st_other);
    118       COPY (st_shndx);
    119     }
    120   else
    121     {
    122       /* Check whether we have to resize the data buffer.  */
    123       if (INVALID_NDX (ndx, Elf64_Sym, &symdata_scn->d))
    124 	{
    125 	  __libelf_seterrno (ELF_E_INVALID_INDEX);
    126 	  goto out;
    127 	}
    128 
    129       ((Elf64_Sym *) symdata_scn->d.d_buf)[ndx] = *src;
    130     }
    131 
    132   /* Now we can store the section index.  */
    133   if (shndx != NULL)
    134     *shndx = srcshndx;
    135 
    136   result = 1;
    137 
    138   /* Mark the section as modified.  */
    139   scn->flags |= ELF_F_DIRTY;
    140 
    141  out:
    142   rwlock_unlock (scn->elf->lock);
    143 
    144   return result;
    145 }
    146