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      1 /* Append new section.
      2    Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
      3    This file is part of Red Hat elfutils.
      4    Written by Ulrich Drepper <drepper (at) redhat.com>, 1998.
      5 
      6    Red Hat elfutils is free software; you can redistribute it and/or modify
      7    it under the terms of the GNU General Public License as published by the
      8    Free Software Foundation; version 2 of the License.
      9 
     10    Red Hat elfutils is distributed in the hope that it will be useful, but
     11    WITHOUT ANY WARRANTY; without even the implied warranty of
     12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     13    General Public License for more details.
     14 
     15    You should have received a copy of the GNU General Public License along
     16    with Red Hat elfutils; if not, write to the Free Software Foundation,
     17    Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
     18 
     19    In addition, as a special exception, Red Hat, Inc. gives You the
     20    additional right to link the code of Red Hat elfutils with code licensed
     21    under any Open Source Initiative certified open source license
     22    (http://www.opensource.org/licenses/index.php) which requires the
     23    distribution of source code with any binary distribution and to
     24    distribute linked combinations of the two.  Non-GPL Code permitted under
     25    this exception must only link to the code of Red Hat elfutils through
     26    those well defined interfaces identified in the file named EXCEPTION
     27    found in the source code files (the "Approved Interfaces").  The files
     28    of Non-GPL Code may instantiate templates or use macros or inline
     29    functions from the Approved Interfaces without causing the resulting
     30    work to be covered by the GNU General Public License.  Only Red Hat,
     31    Inc. may make changes or additions to the list of Approved Interfaces.
     32    Red Hat's grant of this exception is conditioned upon your not adding
     33    any new exceptions.  If you wish to add a new Approved Interface or
     34    exception, please contact Red Hat.  You must obey the GNU General Public
     35    License in all respects for all of the Red Hat elfutils code and other
     36    code used in conjunction with Red Hat elfutils except the Non-GPL Code
     37    covered by this exception.  If you modify this file, you may extend this
     38    exception to your version of the file, but you are not obligated to do
     39    so.  If you do not wish to provide this exception without modification,
     40    you must delete this exception statement from your version and license
     41    this file solely under the GPL without exception.
     42 
     43    Red Hat elfutils is an included package of the Open Invention Network.
     44    An included package of the Open Invention Network is a package for which
     45    Open Invention Network licensees cross-license their patents.  No patent
     46    license is granted, either expressly or impliedly, by designation as an
     47    included package.  Should you wish to participate in the Open Invention
     48    Network licensing program, please visit www.openinventionnetwork.com
     49    <http://www.openinventionnetwork.com>.  */
     50 
     51 #ifdef HAVE_CONFIG_H
     52 # include <config.h>
     53 #endif
     54 
     55 #include <assert.h>
     56 #include <stdbool.h>
     57 #include <stddef.h>
     58 #include <stdlib.h>
     59 #include <string.h>
     60 
     61 #include "libelfP.h"
     62 
     63 
     64 Elf_Scn *
     65 elf_newscn (elf)
     66      Elf *elf;
     67 {
     68   Elf_Scn *result = NULL;
     69   bool first = false;
     70 
     71   if (elf == NULL)
     72     return NULL;
     73 
     74   /* We rely on the prefix of the `elf', `elf32', and `elf64' element
     75      being the same.  */
     76   assert (offsetof (Elf, state.elf.scns_last)
     77 	  == offsetof (Elf, state.elf32.scns_last));
     78   assert (offsetof (Elf, state.elf.scns_last)
     79 	  == offsetof (Elf, state.elf64.scns_last));
     80   assert (offsetof (Elf, state.elf32.scns)
     81 	  == offsetof (Elf, state.elf64.scns));
     82 
     83   rwlock_wrlock (elf->lock);
     84 
     85  again:
     86   if (elf->state.elf.scns_last->cnt < elf->state.elf.scns_last->max)
     87     {
     88       result = &elf->state.elf.scns_last->data[elf->state.elf.scns_last->cnt];
     89 
     90       if (++elf->state.elf.scns_last->cnt == 1
     91 	  && (elf->state.elf.scns_last
     92 	      == (elf->class == ELFCLASS32
     93 		  || (offsetof (Elf, state.elf32.scns)
     94 		      == offsetof (Elf, state.elf64.scns))
     95 		  ? &elf->state.elf32.scns : &elf->state.elf64.scns)))
     96 	/* This is zeroth section.  */
     97 	first = true;
     98       else
     99 	{
    100 	  assert (elf->state.elf.scns_last->cnt > 1);
    101 	  result->index = result[-1].index + 1;
    102 	}
    103     }
    104   else
    105     {
    106       /* We must allocate a new element.  */
    107       Elf_ScnList *newp;
    108 
    109       assert (elf->state.elf.scnincr > 0);
    110 
    111       newp = (Elf_ScnList *) calloc (sizeof (Elf_ScnList)
    112 				     + ((elf->state.elf.scnincr *= 2)
    113 					* sizeof (Elf_Scn)), 1);
    114       if (newp == NULL)
    115 	{
    116 	  __libelf_seterrno (ELF_E_NOMEM);
    117 	  goto out;
    118 	}
    119 
    120       result = &newp->data[0];
    121 
    122       /* One section used.  */
    123       ++newp->cnt;
    124 
    125       /* This is the number of sections we allocated.  */
    126       newp->max = elf->state.elf.scnincr;
    127 
    128       /* Remember the index for the first section in this block.  */
    129       newp->data[0].index
    130 	= 1 + elf->state.elf.scns_last->data[elf->state.elf.scns_last->max - 1].index;
    131 
    132       /* Enqueue the new list element.  */
    133       elf->state.elf.scns_last = elf->state.elf.scns_last->next = newp;
    134     }
    135 
    136   /* Create a section header for this section.  */
    137   if (elf->class == ELFCLASS32)
    138     {
    139       result->shdr.e32 = (Elf32_Shdr *) calloc (1, sizeof (Elf32_Shdr));
    140       if (result->shdr.e32 == NULL)
    141 	{
    142 	  __libelf_seterrno (ELF_E_NOMEM);
    143 	  goto out;
    144 	}
    145     }
    146   else
    147     {
    148       result->shdr.e64 = (Elf64_Shdr *) calloc (1, sizeof (Elf64_Shdr));
    149       if (result->shdr.e64 == NULL)
    150 	{
    151 	  __libelf_seterrno (ELF_E_NOMEM);
    152 	  goto out;
    153 	}
    154     }
    155 
    156   result->elf = elf;
    157   result->shdr_flags = ELF_F_DIRTY | ELF_F_MALLOCED;
    158   result->list = elf->state.elf.scns_last;
    159 
    160   /* Initialize the data part.  */
    161   result->data_read = 1;
    162   if (unlikely (first))
    163     {
    164       /* For the first section we mark the data as already available.  */
    165       //result->data_list_rear = &result->data_list;
    166       first = false;
    167       goto again;
    168     }
    169 
    170   result->flags |= ELF_F_DIRTY;
    171 
    172  out:
    173   rwlock_unlock (elf->lock);
    174 
    175   return result;
    176 }
    177