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/* Close a shared object opened by `_dl_open'.
Copyright (C) 1996, 1997, 1998, 1999 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. 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 <stdlib.h>
#include <string.h>
#include <bits/libc-lock.h>
#include <elf/ldsodefs.h>
#include <sys/types.h>
#include <sys/mman.h>
/* During the program run we must not modify the global data of
loaded shared object simultanously in two threads. Therefore we
protect `dlopen' and `dlclose' in dlclose.c. */
__libc_lock_define (extern, _dl_load_lock)
#define LOSE(s) _dl_signal_error (0, map->l_name, s)
void
internal_function
_dl_close (struct link_map *map)
{
struct link_map **list;
unsigned nsearchlist;
unsigned int i;
if (map->l_opencount == 0)
LOSE ("shared object not open");
/* Acquire the lock. */
__libc_lock_lock (_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. */
--map->l_opencount;
__libc_lock_unlock (_dl_load_lock);
return;
}
list = map->l_searchlist.r_list;
nsearchlist = map->l_searchlist.r_nlist;
/* Call all termination functions at once. */
for (i = 0; i < nsearchlist; ++i)
{
struct link_map *imap = list[i];
if (imap->l_opencount == 1 && imap->l_type == lt_loaded
&& imap->l_info[DT_FINI]
/* Skip any half-cooked objects that were never initialized. */
&& imap->l_init_called)
{
/* When debugging print a message first. */
if (_dl_debug_impcalls)
_dl_debug_message (1, "\ncalling fini: ", imap->l_name,
"\n\n", NULL);
/* Call its termination function. */
(*(void (*) (void)) ((void *) imap->l_addr
+ imap->l_info[DT_FINI]->d_un.d_ptr)) ();
}
}
/* Notify the debugger we are about to remove some loaded objects. */
_r_debug.r_state = RT_DELETE;
_dl_debug_state ();
/* The search list contains a counted reference to each object it
points to, the 0th elt being MAP itself. Decrement the reference
counts on all the objects MAP depends on. */
for (i = 0; i < nsearchlist; ++i)
--list[i]->l_opencount;
/* Check each element of the search list to see if all references to
it are gone. */
for (i = 0; i < nsearchlist; ++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 (imap->l_global)
{
/* This object is in the global scope list. Remove it. */
unsigned int cnt = _dl_main_searchlist->r_nlist;
do
if (cnt-- == 0)
break;
while (_dl_main_searchlist->r_list[cnt] != imap);
if (cnt >= 0)
{
/* The object was already correctly registered. */
while (++cnt < _dl_main_searchlist->r_nlist)
_dl_main_searchlist->r_list[cnt - 1]
= _dl_main_searchlist->r_list[cnt];
--_dl_main_searchlist->r_nlist;
}
else
{
/* This can happen if loading was interrupted by something
like a missing symbol in the newly loaded objects. In
this case the object is already marked as global but
`r_nlist' does not count it in. The pointer is in the
`r_list' array so we keep searching in the other
direction. */
cnt = _dl_main_searchlist->r_nlist;
while (_dl_main_searchlist->r_list[cnt] != imap)
{
++cnt;
/* Note that if _dl_global_scope_alloc is zero we
should never come here in the first place. */
assert (cnt < _dl_global_scope_alloc);
}
}
}
/* 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. */
__munmap ((void *) imap->l_map_start,
imap->l_map_end - imap->l_map_start);
/* Finally, unlink the data structure and free it. */
#ifdef PIC
/* 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
_dl_loaded = imap->l_next;
#endif
if (imap->l_next)
imap->l_next->l_prev = imap->l_prev;
if (imap->l_versions != NULL)
free (imap->l_versions);
if (imap->l_origin != NULL && imap->l_origin != (char *) -1)
free ((char *) imap->l_origin);
/* 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;
free (this);
}
while (lnp != NULL);
/* Remove the searchlists. */
if (imap->l_searchlist.r_duplist != imap->l_searchlist.r_list)
{
/* If a r_list exists there always also is a r_duplist. */
assert (imap->l_searchlist.r_list != NULL);
free (imap->l_searchlist.r_duplist);
}
if (imap != map && imap->l_searchlist.r_list != NULL)
free (imap->l_searchlist.r_list);
free (imap);
}
}
free (list);
if (_dl_global_scope_alloc != 0
&& _dl_main_searchlist->r_nlist == _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 = _dl_main_searchlist->r_list;
/* Put the old map in. */
_dl_main_searchlist->r_list = _dl_initial_searchlist.r_list;
/* Signal that the original map is used. */
_dl_global_scope_alloc = 0;
/* Now free the old map. */
free (old);
}
/* Notify the debugger those objects are finalized and gone. */
_r_debug.r_state = RT_CONSISTENT;
_dl_debug_state ();
/* Release the lock. */
__libc_lock_unlock (_dl_load_lock);
}
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