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glibc/elf/dl-close.c
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/* 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) && map->l_init_called) | |
/* 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) || ! list[i]->l_init_called) | |
/* 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) | |
|| ! dep_list[j]->l_init_called) | |
{ | |
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) || ! imap->l_init_called) | |
/* 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)) DL_DT_FINI_ADDRESS | |
(imap, (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); |