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/* Close a shared object opened by `_dl_open'.
Copyright (C) 1996, 1997, 1998 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 <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 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 > 0 || map->l_type != lt_loaded)
{
/* There are still references to this object. Do nothing more. */
__libc_lock_unlock (_dl_load_lock);
return;
}
/* Notify the debugger we are about to remove some loaded objects. */
_r_debug.r_state = RT_DELETE;
_dl_debug_state ();
list = map->l_searchlist;
/* 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 = 1; i < map->l_nsearchlist; ++i)
--list[i]->l_opencount;
/* Clear the search list so it doesn't get freed while we are still
using it. We have cached it in LIST and will free it when
finished. */
map->l_searchlist = NULL;
/* Check each element of the search list to see if all references to
it are gone. */
for (i = 0; i < map->l_nsearchlist; ++i)
{
struct link_map *imap = list[i];
if (imap->l_opencount == 0 && imap->l_type == lt_loaded)
{
/* That was the last reference, and this was a dlopen-loaded
object. We can unmap it. */
const ElfW(Phdr) *ph;
const ElfW(Phdr) *first, *last;
ElfW(Addr) mapstart, mapend;
if (imap->l_info[DT_FINI])
/* Call its termination function. */
(*(void (*) (void)) ((void *) imap->l_addr +
imap->l_info[DT_FINI]->d_un.d_ptr)) ();
if (imap->l_global)
{
/* This object is in the global scope list. Remove it. */
struct link_map **tail = _dl_global_scope_end;
do
--tail;
while (*tail != imap);
while (tail < _dl_global_scope_end)
{
tail[0] = tail[1];
++tail;
}
--_dl_global_scope_end;
}
/* We can unmap all the maps at once. We just have to determine
the length and the `munmap' call does the rest. */
first = last = NULL;
for (ph = imap->l_phdr; ph < imap->l_phdr + imap->l_phnum; ++ph)
if (ph->p_type == PT_LOAD)
{
if (first == NULL)
first = ph;
last = ph;
}
/* Now we have all the information we need for the unmapping.
See the method used in `_dl_map_object_from_fd'. */
mapstart = first->p_vaddr & ~(first->p_align - 1);
mapend = last->p_vaddr + last->p_memsz;
__munmap ((caddr_t) (imap->l_addr + mapstart), mapend - mapstart);
/* Finally, unlink the data structure and free it. */
if (imap->l_prev)
imap->l_prev->l_next = imap->l_next;
if (imap->l_next)
imap->l_next->l_prev = imap->l_prev;
if (imap->l_searchlist)
free (imap->l_searchlist);
free (imap);
}
}
free (list);
/* 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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