glibc/elf/dl-close.c
Ulrich Drepper 7e036a0134 Update.
2000-10-25  Ulrich Drepper  <drepper@redhat.com>

	* elf/dl-close.c (_dl_close): Optimize a bit by optimizing out the
	nsearchlist variable.
2000-10-25 07:06:03 +00:00

308 lines
8.9 KiB
C

/* Close a shared object opened by `_dl_open'.
Copyright (C) 1996, 1997, 1998, 1999, 2000 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 <libintl.h>
#include <stdlib.h>
#include <string.h>
#include <bits/libc-lock.h>
#include <ldsodefs.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <stdio-common/_itoa.h>
/* Type of the constructor functions. */
typedef void (*fini_t) (void);
/* 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)
void
internal_function
_dl_close (void *_map)
{
struct reldep_list
{
struct link_map **rellist;
unsigned int nrellist;
struct reldep_list *next;
} *reldeps = NULL;
struct link_map **list;
struct link_map *map = _map;
unsigned int i;
unsigned int *new_opencount;
/* First see whether we can remove the object at all. */
if (map->l_flags_1 & DF_1_NODELETE)
/* Nope. Do nothing. */
return;
if (__builtin_expect (map->l_opencount, 1) == 0)
_dl_signal_error (0, map->l_name, N_("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. */
if (__builtin_expect (_dl_debug_files, 0))
{
char buf[20];
buf[sizeof buf - 1] = '\0';
_dl_debug_message (1, "\nclosing file=", map->l_name,
"; opencount == ",
_itoa_word (map->l_opencount,
buf + sizeof buf - 1, 10, 0),
"\n", NULL);
}
/* One decrement the object itself, not the dependencies. */
--map->l_opencount;
__libc_lock_unlock (_dl_load_lock);
return;
}
list = map->l_initfini;
/* Compute the new l_opencount values. */
new_opencount = (unsigned int *) alloca (map->l_searchlist.r_nlist
* 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)
/* Decrement counter. */
&& --new_opencount[i] == 0
/* Test whether this object was also loaded directly. */
&& list[i]->l_searchlist.r_list != NULL)
{
/* In this case we have the decrement all the dependencies of
this object. They are all in MAP's dependency list. */
unsigned int j;
struct link_map **dep_list = list[i]->l_searchlist.r_list;
for (j = 1; j < list[i]->l_searchlist.r_nlist; ++j)
if (! (dep_list[j]->l_flags_1 & DF_1_NODELETE))
{
assert (dep_list[j]->l_idx < map->l_searchlist.r_nlist);
--new_opencount[dep_list[j]->l_idx];
}
}
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_info[DT_FINI] || imap->l_info[DT_FINI_ARRAY])
&& ! (imap->l_flags_1 & DF_1_NODELETE)
/* Skip any half-cooked objects that were never initialized. */
&& imap->l_init_called)
{
/* When debugging print a message first. */
if (__builtin_expect (_dl_debug_impcalls, 0))
_dl_debug_message (1, "\ncalling fini: ", imap->l_name,
"\n\n", NULL);
/* Call its termination function. */
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)));
unsigned int cnt;
for (cnt = 0; cnt < sz; ++cnt)
((fini_t) (imap->l_addr + array[cnt])) ();
}
/* Next try the old-style destructor. */
if (imap->l_info[DT_FINI] != NULL)
(*(void (*) (void)) ((void *) imap->l_addr
+ imap->l_info[DT_FINI]->d_un.d_ptr)) ();
}
/* 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 ();
/* 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. */
int cnt = _dl_main_searchlist->r_nlist;
do
--cnt;
while (_dl_main_searchlist->r_list[cnt] != imap);
/* 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;
}
/* 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
_dl_loaded = imap->l_next;
#endif
--_dl_nloaded;
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);
/* 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));
newrel->rellist = map->l_reldeps;
newrel->nrellist = map->l_reldepsact;
newrel->next = reldeps;
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;
free (this);
}
while (lnp != NULL);
/* Remove the searchlists. */
if (imap != map)
free (imap->l_initfini);
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);
}
}
/* 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)
_dl_close (reldeps->rellist[reldeps->nrellist]);
free (reldeps->rellist);
reldeps = reldeps->next;
}
free (list);
/* Release the lock. */
__libc_lock_unlock (_dl_load_lock);
}
static void
free_mem (void)
{
if (__builtin_expect (_dl_global_scope_alloc, 0) != 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);
}
}
text_set_element (__libc_subfreeres, free_mem);