1 /* Close a shared object opened by `_dl_open'.
2 Copyright (C) 1996-2007, 2009, 2010 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
29 #include <bits/libc-lock.h>
31 #include <sys/types.h>
33 #include <sysdep-cancel.h>
37 /* Type of the constructor functions. */
38 typedef void (*fini_t
) (void);
41 /* Special l_idx value used to indicate which objects remain loaded. */
42 #define IDX_STILL_USED -1
45 /* Returns true we an non-empty was found. */
47 remove_slotinfo (size_t idx
, struct dtv_slotinfo_list
*listp
, size_t disp
,
50 if (idx
- disp
>= listp
->len
)
52 if (listp
->next
== NULL
)
54 /* The index is not actually valid in the slotinfo list,
55 because this object was closed before it was fully set
56 up due to some error. */
57 assert (! should_be_there
);
61 if (remove_slotinfo (idx
, listp
->next
, disp
+ listp
->len
,
65 /* No non-empty entry. Search from the end of this element's
67 idx
= disp
+ listp
->len
;
72 struct link_map
*old_map
= listp
->slotinfo
[idx
- disp
].map
;
74 /* The entry might still be in its unused state if we are closing an
75 object that wasn't fully set up. */
76 if (__builtin_expect (old_map
!= NULL
, 1))
78 assert (old_map
->l_tls_modid
== idx
);
80 /* Mark the entry as unused. */
81 listp
->slotinfo
[idx
- disp
].gen
= GL(dl_tls_generation
) + 1;
82 listp
->slotinfo
[idx
- disp
].map
= NULL
;
85 /* If this is not the last currently used entry no need to look
87 if (idx
!= GL(dl_tls_max_dtv_idx
))
91 while (idx
- disp
> (disp
== 0 ? 1 + GL(dl_tls_static_nelem
) : 0))
95 if (listp
->slotinfo
[idx
- disp
].map
!= NULL
)
97 /* Found a new last used index. */
98 GL(dl_tls_max_dtv_idx
) = idx
;
103 /* No non-entry in this list element. */
109 _dl_close_worker (struct link_map
*map
)
111 /* One less direct use. */
112 --map
->l_direct_opencount
;
114 /* If _dl_close is called recursively (some destructor call dlclose),
115 just record that the parent _dl_close will need to do garbage collection
117 static enum { not_pending
, pending
, rerun
} dl_close_state
;
119 if (map
->l_direct_opencount
> 0 || map
->l_type
!= lt_loaded
120 || dl_close_state
!= not_pending
)
122 if (map
->l_direct_opencount
== 0 && map
->l_type
== lt_loaded
)
123 dl_close_state
= rerun
;
125 /* There are still references to this object. Do nothing more. */
126 if (__builtin_expect (GLRO(dl_debug_mask
) & DL_DEBUG_FILES
, 0))
127 _dl_debug_printf ("\nclosing file=%s; direct_opencount=%u\n",
128 map
->l_name
, map
->l_direct_opencount
);
133 Lmid_t nsid
= map
->l_ns
;
134 struct link_namespaces
*ns
= &GL(dl_ns
)[nsid
];
137 dl_close_state
= pending
;
139 bool any_tls
= false;
140 const unsigned int nloaded
= ns
->_ns_nloaded
;
143 struct link_map
*maps
[nloaded
];
145 /* Run over the list and assign indexes to the link maps and enter
146 them into the MAPS array. */
148 for (struct link_map
*l
= ns
->_ns_loaded
; l
!= NULL
; l
= l
->l_next
)
154 assert (idx
== nloaded
);
156 /* Prepare the bitmaps. */
157 memset (used
, '\0', sizeof (used
));
158 memset (done
, '\0', sizeof (done
));
160 /* Keep track of the lowest index link map we have covered already. */
162 while (++done_index
< nloaded
)
164 struct link_map
*l
= maps
[done_index
];
166 if (done
[done_index
])
167 /* Already handled. */
170 /* Check whether this object is still used. */
171 if (l
->l_type
== lt_loaded
172 && l
->l_direct_opencount
== 0
173 && (l
->l_flags_1
& DF_1_NODELETE
) == 0
174 && !used
[done_index
])
177 /* We need this object and we handle it now. */
178 done
[done_index
] = 1;
179 used
[done_index
] = 1;
180 /* Signal the object is still needed. */
181 l
->l_idx
= IDX_STILL_USED
;
183 /* Mark all dependencies as used. */
184 if (l
->l_initfini
!= NULL
)
186 struct link_map
**lp
= &l
->l_initfini
[1];
189 if ((*lp
)->l_idx
!= IDX_STILL_USED
)
191 assert ((*lp
)->l_idx
>= 0 && (*lp
)->l_idx
< nloaded
);
193 if (!used
[(*lp
)->l_idx
])
195 used
[(*lp
)->l_idx
] = 1;
196 if ((*lp
)->l_idx
- 1 < done_index
)
197 done_index
= (*lp
)->l_idx
- 1;
204 /* And the same for relocation dependencies. */
205 if (l
->l_reldeps
!= NULL
)
206 for (unsigned int j
= 0; j
< l
->l_reldeps
->act
; ++j
)
208 struct link_map
*jmap
= l
->l_reldeps
->list
[j
];
210 if (jmap
->l_idx
!= IDX_STILL_USED
)
212 assert (jmap
->l_idx
>= 0 && jmap
->l_idx
< nloaded
);
214 if (!used
[jmap
->l_idx
])
216 used
[jmap
->l_idx
] = 1;
217 if (jmap
->l_idx
- 1 < done_index
)
218 done_index
= jmap
->l_idx
- 1;
224 /* Sort the entries. */
225 _dl_sort_fini (ns
->_ns_loaded
, maps
, nloaded
, used
, nsid
);
227 /* Call all termination functions at once. */
229 bool do_audit
= GLRO(dl_naudit
) > 0 && !ns
->_ns_loaded
->l_auditing
;
231 bool unload_any
= false;
232 bool scope_mem_left
= false;
233 unsigned int unload_global
= 0;
234 unsigned int first_loaded
= ~0;
235 for (unsigned int i
= 0; i
< nloaded
; ++i
)
237 struct link_map
*imap
= maps
[i
];
239 /* All elements must be in the same namespace. */
240 assert (imap
->l_ns
== nsid
);
244 assert (imap
->l_type
== lt_loaded
245 && (imap
->l_flags_1
& DF_1_NODELETE
) == 0);
247 /* Call its termination function. Do not do it for
248 half-cooked objects. */
249 if (imap
->l_init_called
)
251 /* When debugging print a message first. */
252 if (__builtin_expect (GLRO(dl_debug_mask
) & DL_DEBUG_IMPCALLS
,
254 _dl_debug_printf ("\ncalling fini: %s [%lu]\n\n",
257 if (imap
->l_info
[DT_FINI_ARRAY
] != NULL
)
260 (ElfW(Addr
) *) (imap
->l_addr
261 + imap
->l_info
[DT_FINI_ARRAY
]->d_un
.d_ptr
);
262 unsigned int sz
= (imap
->l_info
[DT_FINI_ARRAYSZ
]->d_un
.d_val
263 / sizeof (ElfW(Addr
)));
266 ((fini_t
) array
[sz
]) ();
269 /* Next try the old-style destructor. */
270 if (imap
->l_info
[DT_FINI
] != NULL
)
271 (*(void (*) (void)) DL_DT_FINI_ADDRESS
272 (imap
, ((void *) imap
->l_addr
273 + imap
->l_info
[DT_FINI
]->d_un
.d_ptr
))) ();
277 /* Auditing checkpoint: we remove an object. */
278 if (__builtin_expect (do_audit
, 0))
280 struct audit_ifaces
*afct
= GLRO(dl_audit
);
281 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
283 if (afct
->objclose
!= NULL
)
284 /* Return value is ignored. */
285 (void) afct
->objclose (&imap
->l_audit
[cnt
].cookie
);
292 /* This object must not be used anymore. */
295 /* We indeed have an object to remove. */
301 /* Remember where the first dynamically loaded object is. */
302 if (i
< first_loaded
)
306 else if (imap
->l_type
== lt_loaded
)
308 struct r_scope_elem
*new_list
= NULL
;
310 if (imap
->l_searchlist
.r_list
== NULL
&& imap
->l_initfini
!= NULL
)
312 /* The object is still used. But one of the objects we are
313 unloading right now is responsible for loading it. If
314 the current object does not have it's own scope yet we
315 have to create one. This has to be done before running
318 To do this count the number of dependencies. */
320 for (cnt
= 1; imap
->l_initfini
[cnt
] != NULL
; ++cnt
)
323 /* We simply reuse the l_initfini list. */
324 imap
->l_searchlist
.r_list
= &imap
->l_initfini
[cnt
+ 1];
325 imap
->l_searchlist
.r_nlist
= cnt
;
327 new_list
= &imap
->l_searchlist
;
330 /* Count the number of scopes which remain after the unload.
331 When we add the local search list count it. Always add
332 one for the terminating NULL pointer. */
333 size_t remain
= (new_list
!= NULL
) + 1;
334 bool removed_any
= false;
335 for (size_t cnt
= 0; imap
->l_scope
[cnt
] != NULL
; ++cnt
)
336 /* This relies on l_scope[] entries being always set either
337 to its own l_symbolic_searchlist address, or some map's
338 l_searchlist address. */
339 if (imap
->l_scope
[cnt
] != &imap
->l_symbolic_searchlist
)
341 struct link_map
*tmap
= (struct link_map
*)
342 ((char *) imap
->l_scope
[cnt
]
343 - offsetof (struct link_map
, l_searchlist
));
344 assert (tmap
->l_ns
== nsid
);
345 if (tmap
->l_idx
== IDX_STILL_USED
)
355 /* Always allocate a new array for the scope. This is
356 necessary since we must be able to determine the last
357 user of the current array. If possible use the link map's
360 struct r_scope_elem
**newp
;
362 #define SCOPE_ELEMS(imap) \
363 (sizeof (imap->l_scope_mem) / sizeof (imap->l_scope_mem[0]))
365 if (imap
->l_scope
!= imap
->l_scope_mem
366 && remain
< SCOPE_ELEMS (imap
))
368 new_size
= SCOPE_ELEMS (imap
);
369 newp
= imap
->l_scope_mem
;
373 new_size
= imap
->l_scope_max
;
374 newp
= (struct r_scope_elem
**)
375 malloc (new_size
* sizeof (struct r_scope_elem
*));
377 _dl_signal_error (ENOMEM
, "dlclose", NULL
,
378 N_("cannot create scope list"));
381 /* Copy over the remaining scope elements. */
383 for (size_t cnt
= 0; imap
->l_scope
[cnt
] != NULL
; ++cnt
)
385 if (imap
->l_scope
[cnt
] != &imap
->l_symbolic_searchlist
)
387 struct link_map
*tmap
= (struct link_map
*)
388 ((char *) imap
->l_scope
[cnt
]
389 - offsetof (struct link_map
, l_searchlist
));
390 if (tmap
->l_idx
!= IDX_STILL_USED
)
392 /* Remove the scope. Or replace with own map's
394 if (new_list
!= NULL
)
396 newp
[remain
++] = new_list
;
403 newp
[remain
++] = imap
->l_scope
[cnt
];
407 struct r_scope_elem
**old
= imap
->l_scope
;
409 imap
->l_scope
= newp
;
411 /* No user anymore, we can free it now. */
412 if (old
!= imap
->l_scope_mem
)
414 if (_dl_scope_free (old
))
415 /* If _dl_scope_free used THREAD_GSCOPE_WAIT (),
416 no need to repeat it. */
417 scope_mem_left
= false;
420 scope_mem_left
= true;
422 imap
->l_scope_max
= new_size
;
425 /* The loader is gone, so mark the object as not having one.
426 Note: l_idx != IDX_STILL_USED -> object will be removed. */
427 if (imap
->l_loader
!= NULL
428 && imap
->l_loader
->l_idx
!= IDX_STILL_USED
)
429 imap
->l_loader
= NULL
;
431 /* Remember where the first dynamically loaded object is. */
432 if (i
< first_loaded
)
437 /* If there are no objects to unload, do nothing further. */
442 /* Auditing checkpoint: we will start deleting objects. */
443 if (__builtin_expect (do_audit
, 0))
445 struct link_map
*head
= ns
->_ns_loaded
;
446 struct audit_ifaces
*afct
= GLRO(dl_audit
);
447 /* Do not call the functions for any auditing object. */
448 if (head
->l_auditing
== 0)
450 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
452 if (afct
->activity
!= NULL
)
453 afct
->activity (&head
->l_audit
[cnt
].cookie
, LA_ACT_DELETE
);
461 /* Notify the debugger we are about to remove some loaded objects. */
462 struct r_debug
*r
= _dl_debug_initialize (0, nsid
);
463 r
->r_state
= RT_DELETE
;
468 /* Some objects are in the global scope list. Remove them. */
469 struct r_scope_elem
*ns_msl
= ns
->_ns_main_searchlist
;
472 unsigned int cnt
= ns_msl
->r_nlist
;
474 while (cnt
> 0 && ns_msl
->r_list
[cnt
- 1]->l_removed
)
477 if (cnt
+ unload_global
== ns_msl
->r_nlist
)
478 /* Speed up removing most recently added objects. */
481 for (i
= 0; i
< cnt
; i
++)
482 if (ns_msl
->r_list
[i
]->l_removed
== 0)
485 ns_msl
->r_list
[j
] = ns_msl
->r_list
[i
];
491 if (!RTLD_SINGLE_THREAD_P
494 || (GL(dl_scope_free_list
) != NULL
495 && GL(dl_scope_free_list
)->count
)))
497 THREAD_GSCOPE_WAIT ();
499 /* Now we can free any queued old scopes. */
500 struct dl_scope_free_list
*fsl
= GL(dl_scope_free_list
);
502 while (fsl
->count
> 0)
503 free (fsl
->list
[--fsl
->count
]);
506 size_t tls_free_start
;
508 tls_free_start
= tls_free_end
= NO_TLS_OFFSET
;
510 /* We modify the list of loaded objects. */
511 __rtld_lock_lock_recursive (GL(dl_load_write_lock
));
513 /* Check each element of the search list to see if all references to
515 for (unsigned int i
= first_loaded
; i
< nloaded
; ++i
)
517 struct link_map
*imap
= maps
[i
];
520 assert (imap
->l_type
== lt_loaded
);
522 /* That was the last reference, and this was a dlopen-loaded
523 object. We can unmap it. */
525 /* Remove the object from the dtv slotinfo array if it uses TLS. */
526 if (__builtin_expect (imap
->l_tls_blocksize
> 0, 0))
530 if (GL(dl_tls_dtv_slotinfo_list
) != NULL
531 && ! remove_slotinfo (imap
->l_tls_modid
,
532 GL(dl_tls_dtv_slotinfo_list
), 0,
533 imap
->l_init_called
))
534 /* All dynamically loaded modules with TLS are unloaded. */
535 GL(dl_tls_max_dtv_idx
) = GL(dl_tls_static_nelem
);
537 if (imap
->l_tls_offset
!= NO_TLS_OFFSET
538 && imap
->l_tls_offset
!= FORCED_DYNAMIC_TLS_OFFSET
)
540 /* Collect a contiguous chunk built from the objects in
541 this search list, going in either direction. When the
542 whole chunk is at the end of the used area then we can
545 if (tls_free_start
== NO_TLS_OFFSET
546 || (size_t) imap
->l_tls_offset
== tls_free_start
)
548 /* Extend the contiguous chunk being reclaimed. */
550 = imap
->l_tls_offset
- imap
->l_tls_blocksize
;
552 if (tls_free_end
== NO_TLS_OFFSET
)
553 tls_free_end
= imap
->l_tls_offset
;
555 else if (imap
->l_tls_offset
- imap
->l_tls_blocksize
557 /* Extend the chunk backwards. */
558 tls_free_end
= imap
->l_tls_offset
;
561 /* This isn't contiguous with the last chunk freed.
562 One of them will be leaked unless we can free
563 one block right away. */
564 if (tls_free_end
== GL(dl_tls_static_used
))
566 GL(dl_tls_static_used
) = tls_free_start
;
567 tls_free_end
= imap
->l_tls_offset
;
569 = tls_free_end
- imap
->l_tls_blocksize
;
571 else if ((size_t) imap
->l_tls_offset
572 == GL(dl_tls_static_used
))
573 GL(dl_tls_static_used
)
574 = imap
->l_tls_offset
- imap
->l_tls_blocksize
;
575 else if (tls_free_end
< (size_t) imap
->l_tls_offset
)
577 /* We pick the later block. It has a chance to
579 tls_free_end
= imap
->l_tls_offset
;
581 = tls_free_end
- imap
->l_tls_blocksize
;
585 if ((size_t) imap
->l_tls_offset
== tls_free_end
)
586 /* Extend the contiguous chunk being reclaimed. */
587 tls_free_end
-= imap
->l_tls_blocksize
;
588 else if (imap
->l_tls_offset
+ imap
->l_tls_blocksize
590 /* Extend the chunk backwards. */
591 tls_free_start
= imap
->l_tls_offset
;
594 /* This isn't contiguous with the last chunk freed.
595 One of them will be leaked. */
596 if (tls_free_end
== GL(dl_tls_static_used
))
597 GL(dl_tls_static_used
) = tls_free_start
;
598 tls_free_start
= imap
->l_tls_offset
;
599 tls_free_end
= tls_free_start
+ imap
->l_tls_blocksize
;
602 # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
607 /* We can unmap all the maps at once. We determined the
608 start address and length when we loaded the object and
609 the `munmap' call does the rest. */
612 /* Finally, unlink the data structure and free it. */
613 if (imap
->l_prev
!= NULL
)
614 imap
->l_prev
->l_next
= imap
->l_next
;
618 assert (nsid
!= LM_ID_BASE
);
620 ns
->_ns_loaded
= imap
->l_next
;
624 if (imap
->l_next
!= NULL
)
625 imap
->l_next
->l_prev
= imap
->l_prev
;
627 free (imap
->l_versions
);
628 if (imap
->l_origin
!= (char *) -1)
629 free ((char *) imap
->l_origin
);
631 free (imap
->l_reldeps
);
633 /* Print debugging message. */
634 if (__builtin_expect (GLRO(dl_debug_mask
) & DL_DEBUG_FILES
, 0))
635 _dl_debug_printf ("\nfile=%s [%lu]; destroying link map\n",
636 imap
->l_name
, imap
->l_ns
);
638 /* This name always is allocated. */
640 /* Remove the list with all the names of the shared object. */
642 struct libname_list
*lnp
= imap
->l_libname
;
645 struct libname_list
*this = lnp
;
647 if (!this->dont_free
)
652 /* Remove the searchlists. */
653 free (imap
->l_initfini
);
655 /* Remove the scope array if we allocated it. */
656 if (imap
->l_scope
!= imap
->l_scope_mem
)
657 free (imap
->l_scope
);
659 if (imap
->l_phdr_allocated
)
660 free ((void *) imap
->l_phdr
);
662 if (imap
->l_rpath_dirs
.dirs
!= (void *) -1)
663 free (imap
->l_rpath_dirs
.dirs
);
664 if (imap
->l_runpath_dirs
.dirs
!= (void *) -1)
665 free (imap
->l_runpath_dirs
.dirs
);
671 __rtld_lock_unlock_recursive (GL(dl_load_write_lock
));
673 /* If we removed any object which uses TLS bump the generation counter. */
676 if (__builtin_expect (++GL(dl_tls_generation
) == 0, 0))
677 _dl_fatal_printf ("TLS generation counter wrapped! Please report as described in <http://www.gnu.org/software/libc/bugs.html>.\n");
679 if (tls_free_end
== GL(dl_tls_static_used
))
680 GL(dl_tls_static_used
) = tls_free_start
;
684 /* Auditing checkpoint: we have deleted all objects. */
685 if (__builtin_expect (do_audit
, 0))
687 struct link_map
*head
= ns
->_ns_loaded
;
688 /* Do not call the functions for any auditing object. */
689 if (head
->l_auditing
== 0)
691 struct audit_ifaces
*afct
= GLRO(dl_audit
);
692 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
694 if (afct
->activity
!= NULL
)
695 afct
->activity (&head
->l_audit
[cnt
].cookie
, LA_ACT_CONSISTENT
);
703 if (__builtin_expect (ns
->_ns_loaded
== NULL
, 0)
704 && nsid
== GL(dl_nns
) - 1)
713 while (GL(dl_ns
)[GL(dl_nns
) - 1]._ns_loaded
== NULL
);
715 /* Notify the debugger those objects are finalized and gone. */
716 r
->r_state
= RT_CONSISTENT
;
719 /* Recheck if we need to retry, release the lock. */
721 if (dl_close_state
== rerun
)
724 dl_close_state
= not_pending
;
729 _dl_close (void *_map
)
731 struct link_map
*map
= _map
;
733 /* First see whether we can remove the object at all. */
734 if (__builtin_expect (map
->l_flags_1
& DF_1_NODELETE
, 0))
736 assert (map
->l_init_called
);
737 /* Nope. Do nothing. */
741 if (__builtin_expect (map
->l_direct_opencount
, 1) == 0)
742 GLRO(dl_signal_error
) (0, map
->l_name
, NULL
, N_("shared object not open"));
744 /* Acquire the lock. */
745 __rtld_lock_lock_recursive (GL(dl_load_lock
));
747 _dl_close_worker (map
);
749 __rtld_lock_unlock_recursive (GL(dl_load_lock
));