Branch data     Line data    Source code

       1                 :            : /* Create new, empty section data.
       2                 :            :    Copyright (C) 1998, 1999, 2000, 2001, 2002, 2015 Red Hat, Inc.
       3                 :            :    This file is part of elfutils.
       4                 :            :    Contributed by Ulrich Drepper <drepper@redhat.com>, 1998.
       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 <stddef.h>
      35                 :            : #include <stdlib.h>
      36                 :            : 
      37                 :            : #include "libelfP.h"
      38                 :            : 
      39                 :            : 
      40                 :            : Elf_Data *
      41                 :    1652390 : elf_newdata (Elf_Scn *scn)
      42                 :            : {
      43                 :    1652390 :   Elf_Data_List *result = NULL;
      44                 :            : 
      45         [ -  + ]:    1652390 :   if (scn == NULL)
      46                 :            :     return NULL;
      47                 :            : 
      48         [ -  + ]:    1652390 :   if (unlikely (scn->index == 0))
      49                 :            :     {
      50                 :            :       /* It is not allowed to add something to the 0th section.  */
      51                 :          0 :       __libelf_seterrno (ELF_E_NOT_NUL_SECTION);
      52                 :          0 :       return NULL;
      53                 :            :     }
      54                 :            : 
      55                 :    1652390 :   if (scn->elf->class == ELFCLASS32
      56                 :            :       || (offsetof (struct Elf, state.elf32.ehdr)
      57                 :            :           == offsetof (struct Elf, state.elf64.ehdr))
      58         [ -  + ]:    1652390 :       ? scn->elf->state.elf32.ehdr == NULL
      59                 :            :       : scn->elf->state.elf64.ehdr == NULL)
      60                 :            :     {
      61                 :          0 :       __libelf_seterrno (ELF_E_WRONG_ORDER_EHDR);
      62                 :          0 :       return NULL;
      63                 :            :     }
      64                 :            : 
      65                 :    1652390 :   rwlock_wrlock (scn->elf->lock);
      66                 :            : 
      67                 :            :   /* data_read is set when data has been read from the ELF image or
      68                 :            :      when a new section has been created by elf_newscn.  If data has
      69                 :            :      been read from the ELF image, then rawdata_base will point to raw
      70                 :            :      data.  If data_read has been set by elf_newscn, then rawdata_base
      71                 :            :      will be NULL.  data_list_rear will be set by elf_getdata if the
      72                 :            :      data has been converted, or by this function, elf_newdata, when
      73                 :            :      new data has been added.
      74                 :            : 
      75                 :            :      Currently elf_getdata and elf_update rely on the fact that when
      76                 :            :      data_list_read is not NULL all they have to do is walk the data
      77                 :            :      list. They will ignore any (unread) raw data in that case.
      78                 :            : 
      79                 :            :      So we need to make sure the data list is setup if there is
      80                 :            :      already data available.  */
      81         [ +  + ]:    1652390 :   if (scn->data_read
      82         [ +  + ]:    1652385 :       && scn->rawdata_base != NULL
      83         [ +  + ]:         31 :       && scn->data_list_rear == NULL)
      84                 :          7 :     __libelf_set_data_list_rdlock (scn, 1);
      85                 :            : 
      86   [ +  +  +  + ]:    1652390 :   if (scn->data_read && scn->data_list_rear == NULL)
      87                 :            :     {
      88                 :            :       /* This means the section was created by the user and this is the
      89                 :            :          first data.  */
      90                 :    1652296 :       result = &scn->data_list;
      91                 :    1652296 :       result->flags = ELF_F_DIRTY;
      92                 :            :     }
      93                 :            :   else
      94                 :            :     {
      95                 :            :       /* It would be more efficient to create new data without
      96                 :            :          reading/converting the data from the file.  But then we
      97                 :            :          have to remember this.  Currently elf_getdata and
      98                 :            :          elf_update rely on the fact that they don't have to
      99                 :            :          load/convert any data if data_list_rear is set.  */
     100         [ +  + ]:         94 :       if (scn->data_read == 0)
     101                 :            :         {
     102         [ -  + ]:          5 :           if (__libelf_set_rawdata_wrlock (scn) != 0)
     103                 :            :             /* Something went wrong.  The error value is already set.  */
     104                 :          0 :             goto out;
     105                 :          5 :           __libelf_set_data_list_rdlock (scn, 1);
     106                 :            :         }
     107                 :            : 
     108                 :            :       /* Create a new, empty data descriptor.  */
     109                 :         94 :       result = calloc (1, sizeof (Elf_Data_List));
     110         [ -  + ]:         94 :       if (result == NULL)
     111                 :            :         {
     112                 :          0 :           __libelf_seterrno (ELF_E_NOMEM);
     113                 :          0 :           goto out;
     114                 :            :         }
     115                 :            : 
     116                 :         94 :       result->flags = ELF_F_DIRTY | ELF_F_MALLOCED;
     117                 :            :     }
     118                 :            : 
     119                 :            :   /* Set the predefined values.  */
     120                 :    1652390 :   result->data.d.d_version = EV_CURRENT;
     121                 :            : 
     122                 :    1652390 :   result->data.s = scn;
     123                 :            : 
     124                 :            :   /* Add to the end of the list.  */
     125         [ +  + ]:    1652390 :   if (scn->data_list_rear != NULL)
     126                 :         94 :     scn->data_list_rear->next = result;
     127                 :            : 
     128                 :    1652390 :   scn->data_list_rear = result;
     129                 :            : 
     130                 :    1652390 :  out:
     131                 :    1652390 :   rwlock_unlock (scn->elf->lock);
     132                 :            : 
     133                 :            :   /* Please note that the following is thread safe and is also defined
     134                 :            :      for RESULT == NULL since it still return NULL.  */
     135                 :    1652390 :   return &result->data.d;
     136                 :            : }