Update.

[thirdparty/glibc.git] / elf / dl-close.c

/* Close a shared object opened by `_dl_open'.
   Copyright (C) 1996-2002, 2003, 2004 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <assert.h>
#include <dlfcn.h>
#include <libintl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <bits/libc-lock.h>
#include <ldsodefs.h>
#include <sys/types.h>
#include <sys/mman.h>


/* Type of the constructor functions.  */
typedef void (*fini_t) (void);


#ifdef USE_TLS
/* Returns true we an non-empty was found.  */
static bool
remove_slotinfo (size_t idx, struct dtv_slotinfo_list *listp, size_t disp,
                 bool should_be_there)
{
  if (idx - disp >= listp->len)
    {
      if (listp->next == NULL)
        {
          /* The index is not actually valid in the slotinfo list,
             because this object was closed before it was fully set
             up due to some error.  */
          assert (! should_be_there);
        }
      else
        {
          if (remove_slotinfo (idx, listp->next, disp + listp->len,
                               should_be_there))
            return true;

          /* No non-empty entry.  Search from the end of this element's
             slotinfo array.  */
          idx = disp + listp->len;
        }
    }
  else
    {
      struct link_map *old_map = listp->slotinfo[idx - disp].map;

      /* The entry might still be in its unused state if we are closing an
         object that wasn't fully set up.  */
      if (__builtin_expect (old_map != NULL, 1))
        {
          assert (old_map->l_tls_modid == idx);

          /* Mark the entry as unused. */
          listp->slotinfo[idx - disp].gen = GL(dl_tls_generation) + 1;
          listp->slotinfo[idx - disp].map = NULL;
        }

      /* If this is not the last currently used entry no need to look
         further.  */
      if (idx != GL(dl_tls_max_dtv_idx))
        return true;
    }

  while (idx - disp > (disp == 0 ? 1 + GL(dl_tls_static_nelem) : 0))
    {
      --idx;

      if (listp->slotinfo[idx - disp].map != NULL)
        {
          /* Found a new last used index.  */
          GL(dl_tls_max_dtv_idx) = idx;
          return true;
        }
    }

  /* No non-entry in this list element.  */
  return false;
}
#endif


void
internal_function
_dl_close (void *_map)
{
  struct reldep_list
  {
    struct link_map **rellist;
    unsigned int nrellist;
    unsigned int nhandled;
    struct reldep_list *next;
    bool handled[0];
  } *reldeps = NULL;
  struct link_map **list;
  struct link_map *map = _map;
  unsigned int i;
  unsigned int *new_opencount;
#ifdef USE_TLS
  bool any_tls = false;
#endif

  /* First see whether we can remove the object at all.  */
  if (__builtin_expect (map->l_flags_1 & DF_1_NODELETE, 0)
      && map->l_init_called)
    /* Nope.  Do nothing.  */
    return;

  if (__builtin_expect (map->l_opencount, 1) == 0)
    _dl_signal_error (0, map->l_name, NULL, N_("shared object not open"));

  /* Acquire the lock.  */
  __rtld_lock_lock_recursive (GL(dl_load_lock));

  /* Decrement the reference count.  */
  if (map->l_opencount > 1 || map->l_type != lt_loaded)
    {
      /* There are still references to this object.  Do nothing more.  */
      if (__builtin_expect (GL(dl_debug_mask) & DL_DEBUG_FILES, 0))
        _dl_debug_printf ("\nclosing file=%s; opencount == %u\n",
                          map->l_name, map->l_opencount);

      /* Decrement the object's reference counter, not the dependencies'.  */
      --map->l_opencount;

      __rtld_lock_unlock_recursive (GL(dl_load_lock));
      return;
    }

  list = map->l_initfini;

  /* Compute the new l_opencount values.  */
  i = map->l_searchlist.r_nlist;
  if (__builtin_expect (i == 0, 0))
    /* This can happen if we handle relocation dependencies for an
       object which wasn't loaded directly.  */
    for (i = 1; list[i] != NULL; ++i)
      ;

  unsigned int nopencount = i;
  new_opencount = (unsigned int *) alloca (i * sizeof (unsigned int));

  for (i = 0; list[i] != NULL; ++i)
    {
      list[i]->l_idx = i;
      new_opencount[i] = list[i]->l_opencount;
    }
  --new_opencount[0];
  for (i = 1; list[i] != NULL; ++i)
    if ((list[i]->l_flags_1 & DF_1_NODELETE) == 0
        /* Decrement counter.  */
        && --new_opencount[i] == 0)
      {
        void mark_removed (struct link_map *remmap)
          {
            /* Test whether this object was also loaded directly.  */
            if (remmap->l_searchlist.r_list != NULL)
              {
                /* In this case we have to decrement all the dependencies of
                   this object.  They are all in MAP's dependency list.  */
                unsigned int j;
                struct link_map **dep_list = remmap->l_searchlist.r_list;

                for (j = 1; j < remmap->l_searchlist.r_nlist; ++j)
                  if (! (dep_list[j]->l_flags_1 & DF_1_NODELETE)
                      || ! dep_list[j]->l_init_called)
                {
                  assert (dep_list[j]->l_idx < map->l_searchlist.r_nlist);
                  if (--new_opencount[dep_list[j]->l_idx] == 0)
                    {
                      assert (dep_list[j]->l_type == lt_loaded);
                      mark_removed (dep_list[j]);
                    }
                }
              }

            if (remmap->l_reldeps != NULL)
              {
                unsigned int j;
                for (j = 0; j < remmap->l_reldepsact; ++j)
                  {
                    /* Find out whether this object is in our list.  */
                    if (remmap->l_reldeps[j]->l_idx < nopencount
                        && (list[remmap->l_reldeps[j]->l_idx]
                            == remmap->l_reldeps[j]))
                      /* Yes, it is.  */
                      if (--new_opencount[remmap->l_reldeps[j]->l_idx] == 0)
                        {
                          /* This one is now gone, too.  */
                          assert (remmap->l_reldeps[j]->l_type == lt_loaded);
                          mark_removed (remmap->l_reldeps[j]);
                        }
                  }
              }
          }

        mark_removed (list[i]);
      }
  assert (new_opencount[0] == 0);

  /* Call all termination functions at once.  */
  for (i = 0; list[i] != NULL; ++i)
    {
      struct link_map *imap = list[i];
      if (new_opencount[i] == 0 && imap->l_type == lt_loaded
          && (imap->l_flags_1 & DF_1_NODELETE) == 0)
        {
          /* When debugging print a message first.  */
          if (__builtin_expect (GL(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0))
            _dl_debug_printf ("\ncalling fini: %s\n\n", imap->l_name);

          /* Call its termination function.  Do not do it for
             half-cooked objects.  */
          if (imap->l_init_called)
            {
              if (imap->l_info[DT_FINI_ARRAY] != NULL)
                {
                  ElfW(Addr) *array =
                    (ElfW(Addr) *) (imap->l_addr
                                    + imap->l_info[DT_FINI_ARRAY]->d_un.d_ptr);
                  unsigned int sz = (imap->l_info[DT_FINI_ARRAYSZ]->d_un.d_val
                                     / sizeof (ElfW(Addr)));

                  while (sz-- > 0)
                    ((fini_t) array[sz]) ();
                }

              /* Next try the old-style destructor.  */
              if (imap->l_info[DT_FINI] != NULL)
                (*(void (*) (void)) DL_DT_FINI_ADDRESS
                 (imap, ((void *) imap->l_addr
                         + imap->l_info[DT_FINI]->d_un.d_ptr))) ();
            }

          /* This object must not be used anymore.  We must remove the
             reference from the scope.  */
          unsigned int j;
          struct link_map **searchlist = map->l_searchlist.r_list;
          unsigned int nsearchlist = map->l_searchlist.r_nlist;

#ifndef NDEBUG
          bool found = false;
#endif
          for (j = 0; j < nsearchlist; ++j)
            if (imap == searchlist[j])
              {
                /* This is the object to remove.  Copy all the
                   following ones.  */
                while (++j < nsearchlist)
                  searchlist[j - 1] = searchlist[j];

                searchlist[j - 1] = NULL;

                --map->l_searchlist.r_nlist;

#ifndef NDEBUG
                found = true;
#endif
                break;
              }
          assert (found);
        }
      else if (new_opencount[i] != 0 && imap->l_type == lt_loaded
               && imap->l_searchlist.r_list == NULL
               && imap->l_initfini != NULL)
        {
          /* The object is still used.  But the object we are
             unloading right now is responsible for loading it.  If
             the current object does not have it's own scope yet we
             have to create one.  This has to be done before running
             the finalizers.

             To do this count the number of dependencies.  */
          unsigned int cnt;
          for (cnt = 1; imap->l_initfini[cnt] != NULL; ++cnt)
            if (imap->l_initfini[cnt]->l_idx >= i
                && imap->l_initfini[cnt]->l_idx < nopencount)
              ++new_opencount[imap->l_initfini[cnt]->l_idx];
            else
              ++imap->l_initfini[cnt]->l_opencount;

          /* We simply reuse the l_initfini list.  */
          imap->l_searchlist.r_list = &imap->l_initfini[cnt + 1];
          imap->l_searchlist.r_nlist = cnt;

          for (cnt = 0; imap->l_scope[cnt] != NULL; ++cnt)
            if (imap->l_scope[cnt] == &map->l_searchlist)
              {
                imap->l_scope[cnt] = &imap->l_searchlist;
                break;
              }
        }

      /* Store the new l_opencount value.  */
      imap->l_opencount = new_opencount[i];

      /* Just a sanity check.  */
      assert (imap->l_type == lt_loaded || imap->l_opencount > 0);
    }

  /* Notify the debugger we are about to remove some loaded objects.  */
  _r_debug.r_state = RT_DELETE;
  _dl_debug_state ();

#ifdef USE_TLS
  size_t tls_free_start;
  size_t tls_free_end;
  tls_free_start = tls_free_end = NO_TLS_OFFSET;
#endif

  /* Check each element of the search list to see if all references to
     it are gone.  */
  for (i = 0; list[i] != NULL; ++i)
    {
      struct link_map *imap = list[i];
      if (imap->l_opencount == 0 && imap->l_type == lt_loaded)
        {
          struct libname_list *lnp;

          /* That was the last reference, and this was a dlopen-loaded
             object.  We can unmap it.  */
          if (__builtin_expect (imap->l_global, 0))
            {
              /* This object is in the global scope list.  Remove it.  */
              unsigned int cnt = GL(dl_main_searchlist)->r_nlist;

              do
                --cnt;
              while (GL(dl_main_searchlist)->r_list[cnt] != imap);

              /* The object was already correctly registered.  */
              while (++cnt < GL(dl_main_searchlist)->r_nlist)
                GL(dl_main_searchlist)->r_list[cnt - 1]
                  = GL(dl_main_searchlist)->r_list[cnt];

              --GL(dl_main_searchlist)->r_nlist;
            }

#ifdef USE_TLS
          /* Remove the object from the dtv slotinfo array if it uses TLS.  */
          if (__builtin_expect (imap->l_tls_blocksize > 0, 0))
            {
              any_tls = true;

              if (! remove_slotinfo (imap->l_tls_modid,
                                     GL(dl_tls_dtv_slotinfo_list), 0,
                                     imap->l_init_called))
                /* All dynamically loaded modules with TLS are unloaded.  */
                GL(dl_tls_max_dtv_idx) = GL(dl_tls_static_nelem);

              if (imap->l_tls_offset != NO_TLS_OFFSET)
                {
                  /* Collect a contiguous chunk built from the objects in
                     this search list, going in either direction.  When the
                     whole chunk is at the end of the used area then we can
                     reclaim it.  */
# if TLS_TCB_AT_TP
                  if (tls_free_start == NO_TLS_OFFSET
                      || (size_t) imap->l_tls_offset == tls_free_start)
                    {
                      /* Extend the contiguous chunk being reclaimed.  */
                      tls_free_start
                        = imap->l_tls_offset - imap->l_tls_blocksize;

                      if (tls_free_end == NO_TLS_OFFSET)
                        tls_free_end = imap->l_tls_offset;
                    }
                  else if (imap->l_tls_offset - imap->l_tls_blocksize
                           == tls_free_end)
                    /* Extend the chunk backwards.  */
                    tls_free_end = imap->l_tls_offset;
                  else
                    {
                      /* This isn't contiguous with the last chunk freed.
                         One of them will be leaked unless we can free
                         one block right away.  */
                      if (tls_free_end == GL(dl_tls_static_used))
                        {
                          GL(dl_tls_static_used) = tls_free_start;
                          tls_free_end = imap->l_tls_offset;
                          tls_free_start
                            = tls_free_end - imap->l_tls_blocksize;
                        }
                      else if ((size_t) imap->l_tls_offset
                               == GL(dl_tls_static_used))
                        GL(dl_tls_static_used)
                          = imap->l_tls_offset - imap->l_tls_blocksize;
                      else if (tls_free_end < (size_t) imap->l_tls_offset)
                        {
                          /* We pick the later block.  It has a chance to
                             be freed.  */
                          tls_free_end = imap->l_tls_offset;
                          tls_free_start
                            = tls_free_end - imap->l_tls_blocksize;
                        }
                    }
# elif TLS_DTV_AT_TP
                  if ((size_t) imap->l_tls_offset == tls_free_end)
                    /* Extend the contiguous chunk being reclaimed.  */
                    tls_free_end -= imap->l_tls_blocksize;
                  else if (imap->l_tls_offset + imap->l_tls_blocksize
                           == tls_free_start)
                    /* Extend the chunk backwards.  */
                    tls_free_start = imap->l_tls_offset;
                  else
                    {
                      /* This isn't contiguous with the last chunk freed.
                         One of them will be leaked.  */
                      if (tls_free_end == GL(dl_tls_static_used))
                        GL(dl_tls_static_used) = tls_free_start;
                      tls_free_start = imap->l_tls_offset;
                      tls_free_end = tls_free_start + imap->l_tls_blocksize;
                    }
# else
#  error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
# endif
                }
            }
#endif

          /* We can unmap all the maps at once.  We determined the
             start address and length when we loaded the object and
             the `munmap' call does the rest.  */
          DL_UNMAP (imap);

          /* Finally, unlink the data structure and free it.  */
#ifdef SHARED
          /* We will unlink the first object only if this is a statically
             linked program.  */
          assert (imap->l_prev != NULL);
          imap->l_prev->l_next = imap->l_next;
#else
          if (imap->l_prev != NULL)
            imap->l_prev->l_next = imap->l_next;
          else
            GL(dl_loaded) = imap->l_next;
#endif
          --GL(dl_nloaded);
          if (imap->l_next)
            imap->l_next->l_prev = imap->l_prev;

          free (imap->l_versions);
          if (imap->l_origin != (char *) -1)
            free ((char *) imap->l_origin);

          /* If the object has relocation dependencies save this
             information for latter.  */
          if (__builtin_expect (imap->l_reldeps != NULL, 0))
            {
              struct reldep_list *newrel;

              newrel = (struct reldep_list *) alloca (sizeof (*reldeps)
                                                      + (imap->l_reldepsact
                                                         * sizeof (bool)));
              newrel->rellist = imap->l_reldeps;
              newrel->nrellist = imap->l_reldepsact;
              newrel->next = reldeps;

              newrel->nhandled = imap->l_reldepsact;
              unsigned int j;
              for (j = 0; j < imap->l_reldepsact; ++j)
                {
                  /* Find out whether this object is in our list.  */
                  if (imap->l_reldeps[j]->l_idx < nopencount
                      && list[imap->l_reldeps[j]->l_idx] == imap->l_reldeps[j])
                    /* Yes, it is.  */
                    newrel->handled[j] = true;
                  else
                    newrel->handled[j] = false;
                }

              reldeps = newrel;
            }

          /* This name always is allocated.  */
          free (imap->l_name);
          /* Remove the list with all the names of the shared object.  */
          lnp = imap->l_libname;
          do
            {
              struct libname_list *this = lnp;
              lnp = lnp->next;
              if (!this->dont_free)
                free (this);
            }
          while (lnp != NULL);

          /* Remove the searchlists.  */
          if (imap != map)
            free (imap->l_initfini);

          /* Remove the scope array if we allocated it.  */
          if (imap->l_scope != imap->l_scope_mem)
            free (imap->l_scope);

          if (imap->l_phdr_allocated)
            free ((void *) imap->l_phdr);

          if (imap->l_rpath_dirs.dirs != (void *) -1)
            free (imap->l_rpath_dirs.dirs);
          if (imap->l_runpath_dirs.dirs != (void *) -1)
            free (imap->l_runpath_dirs.dirs);

          free (imap);
        }
    }

#ifdef USE_TLS
  /* If we removed any object which uses TLS bump the generation counter.  */
  if (any_tls)
    {
      if (__builtin_expect (++GL(dl_tls_generation) == 0, 0))
        __libc_fatal (_("TLS generation counter wrapped!  Please send report with the 'glibcbug' script."));

      if (tls_free_end == GL(dl_tls_static_used))
        GL(dl_tls_static_used) = tls_free_start;
    }
#endif

  /* Notify the debugger those objects are finalized and gone.  */
  _r_debug.r_state = RT_CONSISTENT;
  _dl_debug_state ();

  /* Now we can perhaps also remove the modules for which we had
     dependencies because of symbol lookup.  */
  while (__builtin_expect (reldeps != NULL, 0))
    {
      while (reldeps->nrellist-- > 0)
        /* Some of the relocation dependencies might be on the
           dependency list of the object we are closing right now.
           They were already handled.  Do not close them again.  */
        if (reldeps->nrellist < reldeps->nhandled
            && ! reldeps->handled[reldeps->nrellist])
          _dl_close (reldeps->rellist[reldeps->nrellist]);

      free (reldeps->rellist);

      reldeps = reldeps->next;
    }

  free (list);

  /* Release the lock.  */
  __rtld_lock_unlock_recursive (GL(dl_load_lock));
}
libc_hidden_def (_dl_close)


#ifdef USE_TLS
static bool
free_slotinfo (struct dtv_slotinfo_list **elemp)
{
  size_t cnt;

  if (*elemp == NULL)
    /* Nothing here, all is removed (or there never was anything).  */
    return true;

  if (!free_slotinfo (&(*elemp)->next))
    /* We cannot free the entry.  */
    return false;

  /* That cleared our next pointer for us.  */

  for (cnt = 0; cnt < (*elemp)->len; ++cnt)
    if ((*elemp)->slotinfo[cnt].map != NULL)
      /* Still used.  */
      return false;

  /* We can remove the list element.  */
  free (*elemp);
  *elemp = NULL;

  return true;
}
#endif


libc_freeres_fn (free_mem)
{
  if (__builtin_expect (GL(dl_global_scope_alloc), 0) != 0
      && GL(dl_main_searchlist)->r_nlist == GL(dl_initial_searchlist).r_nlist)
    {
      /* All object dynamically loaded by the program are unloaded.  Free
         the memory allocated for the global scope variable.  */
      struct link_map **old = GL(dl_main_searchlist)->r_list;

      /* Put the old map in.  */
      GL(dl_main_searchlist)->r_list = GL(dl_initial_searchlist).r_list;
      /* Signal that the original map is used.  */
      GL(dl_global_scope_alloc) = 0;

      /* Now free the old map.  */
      free (old);
    }

#ifdef USE_TLS
  if (USE___THREAD || GL(dl_tls_dtv_slotinfo_list) != NULL)
    {
      /* Free the memory allocated for the dtv slotinfo array.  We can do
         this only if all modules which used this memory are unloaded.  */
# ifdef SHARED
      if (GL(dl_initial_dtv) == NULL)
        /* There was no initial TLS setup, it was set up later when
           it used the normal malloc.  */
        free_slotinfo (&GL(dl_tls_dtv_slotinfo_list));
# endif
      /* The first element of the list does not have to be deallocated.
         It was allocated in the dynamic linker (i.e., with a different
         malloc), and in the static library it's in .bss space.  */
      free_slotinfo (&GL(dl_tls_dtv_slotinfo_list)->next);
    }
#endif
}