/* Free resources associated with Elf descriptor.

   Copyright (C) 1998,1999,2000,2001,2002,2004,2005,2007,2015,2016 Red Hat, Inc.

   Copyright (C) 2023 Mark J. Wielaard <mark@klomp.org>

   This file is part of elfutils.

   Written by Ulrich Drepper <drepper@redhat.com>, 1998.

   This file is free software; you can redistribute it and/or modify

   it under the terms of either

     * the GNU Lesser General Public License as published by the Free

       Software Foundation; either version 3 of the License, or (at

       your option) any later version

   or

     * the GNU General Public License as published by the Free

       Software Foundation; either version 2 of the License, or (at

       your option) any later version

   or both in parallel, as here.

   elfutils is distributed in the hope that it will be useful, but

   WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   General Public License for more details.

   You should have received copies of the GNU General Public License and

   the GNU Lesser General Public License along with this program.  If

   not, see <http://www.gnu.org/licenses/>.  */

#ifdef HAVE_CONFIG_H

# include <config.h>

#endif

#include <assert.h>

#include <search.h>

#include <stddef.h>

#include <stdlib.h>

#include "libelfP.h"

static void

free_chunk (void *n)

{

  Elf_Data_Chunk *rawchunk = (Elf_Data_Chunk *)n;

  if (rawchunk->dummy_scn.flags & ELF_F_MALLOCED)

    free (rawchunk->data.d.d_buf);

  free (rawchunk);

}

int

elf_end (Elf *elf)

{

  Elf *parent;

  if (elf == NULL)

    /* This is allowed and is a no-op.  */

    return 0;

  /* Make sure we are alone.  */

  rwlock_wrlock (elf->lock);

  if (elf->ref_count != 0 && --elf->ref_count != 0)

    {

      /* Not yet the last activation.  */

      int result = elf->ref_count;

      rwlock_unlock (elf->lock);

      return result;

    }

  if (elf->kind == ELF_K_AR)

    {

      /* We cannot remove the descriptor now since we still have some

   descriptors which depend on it.  But we can free the archive

   symbol table since this is only available via the archive ELF

   descriptor.  The long name table cannot be freed yet since

   the archive headers for the ELF files in the archive point

   into this array.  */

      if (elf->state.ar.ar_sym != (Elf_Arsym *) -1l)

  free (elf->state.ar.ar_sym);

      elf->state.ar.ar_sym = NULL;

      if (elf->state.ar.children != NULL)

  {

    rwlock_unlock(elf->lock);

    return 0;

  }

    }

  /* Remove this structure from the children list.  */

  parent = elf->parent;

  if (parent != NULL)

    {

      /* This is tricky.  Lock must be acquire from the father to

   the child but here we already have the child lock.  We

   solve this problem by giving free the child lock.  The

   state of REF_COUNT==0 is handled all over the library, so

   this should be ok.  */

      rwlock_unlock (elf->lock);

      rwlock_rdlock (parent->lock);

      rwlock_wrlock (elf->lock);

      if (parent->state.ar.children == elf)

  parent->state.ar.children = elf->next;

      else

  {

    struct Elf *child = parent->state.ar.children;

    while (child->next != elf)

      child = child->next;

    child->next = elf->next;

  }

      rwlock_unlock (parent->lock);

    }

  /* This was the last activation.  Free all resources.  */

  switch (elf->kind)

    {

    case ELF_K_AR:

      if (elf->state.ar.long_names != NULL)

  free (elf->state.ar.long_names);

      break;

    case ELF_K_ELF:

      {

  search_tree *rawchunk_tree

    = (elf->class == ELFCLASS32

       || (offsetof (struct Elf, state.elf32.rawchunk_tree)

     == offsetof (struct Elf, state.elf64.rawchunk_tree))

       ? &elf->state.elf32.rawchunk_tree

       : &elf->state.elf64.rawchunk_tree);

  eu_search_tree_fini (rawchunk_tree, free_chunk);

  Elf_ScnList *list = (elf->class == ELFCLASS32

           || (offsetof (struct Elf, state.elf32.scns)

         == offsetof (struct Elf, state.elf64.scns))

           ? &elf->state.elf32.scns

           : &elf->state.elf64.scns);

  do

    {

      /* Free all separately allocated section headers.  */

      size_t cnt = list->max;

      while (cnt-- > 0)

        {

    /* These pointers can be NULL; it's safe to use

       'free' since it will check for this.  */

    Elf_Scn *scn = &list->data[cnt];

    Elf_Data_List *runp;

    if ((scn->shdr_flags & ELF_F_MALLOCED) != 0)

      /* It doesn't matter which pointer.  */

      free (scn->shdr.e32);

    /* Free zdata if uncompressed, but not yet used as

       rawdata_base.  If it is already used it will be

       freed below.  */

    if (scn->zdata_base != scn->rawdata_base)

      {

        free (scn->zdata_base);

        scn->zdata_base = NULL;

      }

    /* If the file has the same byte order and the

       architecture doesn't require overly stringent

       alignment the raw data buffer is the same as the

       one used for presenting to the caller.  */

    if (scn->data_base != scn->rawdata_base)

      free (scn->data_base);

    /* The section data is allocated if we couldn't mmap

       the file.  Or if we had to decompress.  */

    if (elf->map_address == NULL

        || scn->rawdata_base == scn->zdata_base

        || (scn->flags & ELF_F_MALLOCED) != 0)

      free (scn->rawdata_base);

    /* Free the list of data buffers for the section.

       We don't free the buffers themselves since this

       is the users job.  */

    runp = scn->data_list.next;

    while (runp != NULL)

      {

        Elf_Data_List *oldp = runp;

        runp = runp->next;

        if ((oldp->flags & ELF_F_MALLOCED) != 0)

          free (oldp);

      }

        }

      /* Free the memory for the array.  */

      Elf_ScnList *oldp = list;

      list = list->next;

      assert (list == NULL || oldp->cnt == oldp->max);

      if (oldp != (elf->class == ELFCLASS32

       || (offsetof (struct Elf, state.elf32.scns)

           == offsetof (struct Elf, state.elf64.scns))

       ? &elf->state.elf32.scns

       : &elf->state.elf64.scns))

        free (oldp);

    }

  while (list != NULL);

      }

      /* Free the section header.  */

      if (elf->state.elf.shdr_malloced  != 0)

  free (elf->class == ELFCLASS32

        || (offsetof (struct Elf, state.elf32.shdr)

      == offsetof (struct Elf, state.elf64.shdr))

        ? (void *) elf->state.elf32.shdr

        : (void *) elf->state.elf64.shdr);

      /* Free the program header.  */

      if ((elf->state.elf.phdr_flags & ELF_F_MALLOCED) != 0)

  free (elf->class == ELFCLASS32

        || (offsetof (struct Elf, state.elf32.phdr)

      == offsetof (struct Elf, state.elf64.phdr))

        ? (void *) elf->state.elf32.phdr

        : (void *) elf->state.elf64.phdr);

      break;

    default:

      break;

    }

  if (elf->map_address != NULL && parent == NULL)

    {

      /* The file was read or mapped for this descriptor.  */

      if ((elf->flags & ELF_F_MALLOCED) != 0)

  free (elf->map_address);

      else if ((elf->flags & ELF_F_MMAPPED) != 0)

  munmap (elf->map_address, elf->maximum_size);

    }

  rwlock_unlock (elf->lock);

  rwlock_fini (elf->lock);

  /* Finally the descriptor itself.  */

  free (elf);

  return (parent != NULL && parent->ref_count == 0

    ? INTUSE(elf_end) (parent) : 0);

}

INTDEF(elf_end)