/* Close a shared object opened by `_dl_open'.
- Copyright (C) 1996-2001, 2002 Free Software Foundation, Inc.
+ Copyright (C) 1996-2019 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library; if not, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
#include <assert.h>
#include <dlfcn.h>
+#include <errno.h>
#include <libintl.h>
+#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
-#include <bits/libc-lock.h>
+#include <unistd.h>
+#include <libc-lock.h>
#include <ldsodefs.h>
#include <sys/types.h>
#include <sys/mman.h>
+#include <sysdep-cancel.h>
+#include <tls.h>
+#include <stap-probe.h>
+
+#include <dl-unmap-segments.h>
/* Type of the constructor functions. */
typedef void (*fini_t) (void);
-#ifdef USE_TLS
+/* Special l_idx value used to indicate which objects remain loaded. */
+#define IDX_STILL_USED -1
+
+
/* Returns true we an non-empty was found. */
static bool
remove_slotinfo (size_t idx, struct dtv_slotinfo_list *listp, size_t disp,
/* The entry might still be in its unused state if we are closing an
object that wasn't fully set up. */
- if (__builtin_expect (old_map != NULL, 1))
+ if (__glibc_likely (old_map != NULL))
{
assert (old_map->l_tls_modid == idx);
return true;
}
- while (idx - disp > disp == 0 ? 1 + GL(dl_tls_static_nelem) : 0)
+ while (idx - disp > (disp == 0 ? 1 + GL(dl_tls_static_nelem) : 0))
{
--idx;
/* No non-entry in this list element. */
return false;
}
-#endif
void
-internal_function
-_dl_close (void *_map)
+_dl_close_worker (struct link_map *map, bool force)
{
- 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;
-#ifdef USE_TLS
- bool any_tls = false;
-#endif
-
- /* First see whether we can remove the object at all. */
- if (__builtin_expect (map->l_flags_1 & DF_1_NODELETE, 0)
- && map->l_init_called)
- /* Nope. Do nothing. */
- return;
+ /* One less direct use. */
+ --map->l_direct_opencount;
- if (__builtin_expect (map->l_opencount, 1) == 0)
- _dl_signal_error (0, map->l_name, NULL, N_("shared object not open"));
+ /* If _dl_close is called recursively (some destructor call dlclose),
+ just record that the parent _dl_close will need to do garbage collection
+ again and return. */
+ static enum { not_pending, pending, rerun } dl_close_state;
- /* Acquire the lock. */
- __libc_lock_lock_recursive (GL(dl_load_lock));
-
- /* Decrement the reference count. */
- if (map->l_opencount > 1 || map->l_type != lt_loaded)
+ if (map->l_direct_opencount > 0 || map->l_type != lt_loaded
+ || dl_close_state != not_pending)
{
- /* There are still references to this object. Do nothing more. */
- if (__builtin_expect (GL(dl_debug_mask) & DL_DEBUG_FILES, 0))
- _dl_debug_printf ("\nclosing file=%s; opencount == %u\n",
- map->l_name, map->l_opencount);
+ if (map->l_direct_opencount == 0 && map->l_type == lt_loaded)
+ dl_close_state = rerun;
- /* One decrement the object itself, not the dependencies. */
- --map->l_opencount;
+ /* There are still references to this object. Do nothing more. */
+ if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES))
+ _dl_debug_printf ("\nclosing file=%s; direct_opencount=%u\n",
+ map->l_name, map->l_direct_opencount);
- __libc_lock_unlock_recursive (GL(dl_load_lock));
return;
}
- list = map->l_initfini;
+ Lmid_t nsid = map->l_ns;
+ struct link_namespaces *ns = &GL(dl_ns)[nsid];
- /* Compute the new l_opencount values. */
- i = map->l_searchlist.r_nlist;
- if (__builtin_expect (i == 0, 0))
- /* This can happen if we handle relocation dependencies for an
- object which wasn't loaded directly. */
- for (i = 1; list[i] != NULL; ++i)
- ;
+ retry:
+ dl_close_state = pending;
- new_opencount = (unsigned int *) alloca (i * sizeof (unsigned int));
-
- for (i = 0; list[i] != NULL; ++i)
+ bool any_tls = false;
+ const unsigned int nloaded = ns->_ns_nloaded;
+ char used[nloaded];
+ char done[nloaded];
+ struct link_map *maps[nloaded];
+
+ /* Clear DF_1_NODELETE to force object deletion. We don't need to touch
+ l_tls_dtor_count because forced object deletion only happens when an
+ error occurs during object load. Destructor registration for TLS
+ non-POD objects should not have happened till then for this
+ object. */
+ if (force)
+ map->l_flags_1 &= ~DF_1_NODELETE;
+
+ /* Run over the list and assign indexes to the link maps and enter
+ them into the MAPS array. */
+ int idx = 0;
+ for (struct link_map *l = ns->_ns_loaded; l != NULL; l = l->l_next)
{
- list[i]->l_idx = i;
- new_opencount[i] = list[i]->l_opencount;
+ l->l_idx = idx;
+ maps[idx] = l;
+ ++idx;
+
}
- --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 (idx == nloaded);
+
+ /* Prepare the bitmaps. */
+ memset (used, '\0', sizeof (used));
+ memset (done, '\0', sizeof (done));
+
+ /* Keep track of the lowest index link map we have covered already. */
+ int done_index = -1;
+ while (++done_index < nloaded)
+ {
+ struct link_map *l = maps[done_index];
+
+ if (done[done_index])
+ /* Already handled. */
+ continue;
+
+ /* Check whether this object is still used. */
+ if (l->l_type == lt_loaded
+ && l->l_direct_opencount == 0
+ && (l->l_flags_1 & DF_1_NODELETE) == 0
+ /* See CONCURRENCY NOTES in cxa_thread_atexit_impl.c to know why
+ acquire is sufficient and correct. */
+ && atomic_load_acquire (&l->l_tls_dtor_count) == 0
+ && !used[done_index])
+ continue;
+
+ /* We need this object and we handle it now. */
+ done[done_index] = 1;
+ used[done_index] = 1;
+ /* Signal the object is still needed. */
+ l->l_idx = IDX_STILL_USED;
+
+ /* Mark all dependencies as used. */
+ if (l->l_initfini != NULL)
+ {
+ /* We are always the zeroth entry, and since we don't include
+ ourselves in the dependency analysis start at 1. */
+ struct link_map **lp = &l->l_initfini[1];
+ while (*lp != NULL)
{
- assert (dep_list[j]->l_idx < map->l_searchlist.r_nlist);
- --new_opencount[dep_list[j]->l_idx];
+ if ((*lp)->l_idx != IDX_STILL_USED)
+ {
+ assert ((*lp)->l_idx >= 0 && (*lp)->l_idx < nloaded);
+
+ if (!used[(*lp)->l_idx])
+ {
+ used[(*lp)->l_idx] = 1;
+ /* If we marked a new object as used, and we've
+ already processed it, then we need to go back
+ and process again from that point forward to
+ ensure we keep all of its dependencies also. */
+ if ((*lp)->l_idx - 1 < done_index)
+ done_index = (*lp)->l_idx - 1;
+ }
+ }
+
+ ++lp;
}
- }
- assert (new_opencount[0] == 0);
+ }
+ /* And the same for relocation dependencies. */
+ if (l->l_reldeps != NULL)
+ for (unsigned int j = 0; j < l->l_reldeps->act; ++j)
+ {
+ struct link_map *jmap = l->l_reldeps->list[j];
+
+ if (jmap->l_idx != IDX_STILL_USED)
+ {
+ assert (jmap->l_idx >= 0 && jmap->l_idx < nloaded);
+
+ if (!used[jmap->l_idx])
+ {
+ used[jmap->l_idx] = 1;
+ if (jmap->l_idx - 1 < done_index)
+ done_index = jmap->l_idx - 1;
+ }
+ }
+ }
+ }
+
+ /* Sort the entries. We can skip looking for the binary itself which is
+ at the front of the search list for the main namespace. */
+ _dl_sort_maps (maps + (nsid == LM_ID_BASE), nloaded - (nsid == LM_ID_BASE),
+ used + (nsid == LM_ID_BASE), true);
/* Call all termination functions at once. */
- for (i = 0; list[i] != NULL; ++i)
+#ifdef SHARED
+ bool do_audit = GLRO(dl_naudit) > 0 && !ns->_ns_loaded->l_auditing;
+#endif
+ bool unload_any = false;
+ bool scope_mem_left = false;
+ unsigned int unload_global = 0;
+ unsigned int first_loaded = ~0;
+ for (unsigned int i = 0; i < nloaded; ++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)
+ struct link_map *imap = maps[i];
+
+ /* All elements must be in the same namespace. */
+ assert (imap->l_ns == nsid);
+
+ if (!used[i])
{
- /* When debugging print a message first. */
- if (__builtin_expect (GL(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0))
- _dl_debug_printf ("\ncalling fini: %s\n\n", imap->l_name);
+ assert (imap->l_type == lt_loaded
+ && (imap->l_flags_1 & DF_1_NODELETE) == 0);
- /* Call its termination function. */
- if (imap->l_info[DT_FINI_ARRAY] != NULL)
+ /* Call its termination function. Do not do it for
+ half-cooked objects. */
+ if (imap->l_init_called)
{
- 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;
+ /* When debugging print a message first. */
+ if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS,
+ 0))
+ _dl_debug_printf ("\ncalling fini: %s [%lu]\n\n",
+ imap->l_name, nsid);
+
+ 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)));
+
+ while (sz-- > 0)
+ ((fini_t) array[sz]) ();
+ }
- 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)
+ DL_CALL_DT_FINI (imap, ((void *) imap->l_addr
+ + imap->l_info[DT_FINI]->d_un.d_ptr));
}
- /* 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)) ();
+#ifdef SHARED
+ /* Auditing checkpoint: we remove an object. */
+ if (__glibc_unlikely (do_audit))
+ {
+ struct audit_ifaces *afct = GLRO(dl_audit);
+ for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
+ {
+ if (afct->objclose != NULL)
+ /* Return value is ignored. */
+ (void) afct->objclose (&imap->l_audit[cnt].cookie);
+
+ afct = afct->next;
+ }
+ }
+#endif
+
+ /* This object must not be used anymore. */
+ imap->l_removed = 1;
+
+ /* We indeed have an object to remove. */
+ unload_any = true;
+
+ if (imap->l_global)
+ ++unload_global;
+
+ /* Remember where the first dynamically loaded object is. */
+ if (i < first_loaded)
+ first_loaded = i;
}
- else if (new_opencount[i] != 0 && imap->l_type == lt_loaded)
+ /* Else used[i]. */
+ else if (imap->l_type == lt_loaded)
{
- /* The object is still used. But the object we are unloading
- right now is responsible for loading it and therefore we
- have the search list of the current object in its scope.
- Remove it. */
- struct r_scope_elem **runp = imap->l_scope;
-
- while (*runp != NULL)
- if (*runp == &map->l_searchlist)
+ struct r_scope_elem *new_list = NULL;
+
+ if (imap->l_searchlist.r_list == NULL && imap->l_initfini != NULL)
+ {
+ /* The object is still used. But one of the objects we are
+ unloading right now is responsible for loading it. If
+ the current object does not have it's own scope yet we
+ have to create one. This has to be done before running
+ the finalizers.
+
+ To do this count the number of dependencies. */
+ unsigned int cnt;
+ for (cnt = 1; imap->l_initfini[cnt] != NULL; ++cnt)
+ ;
+
+ /* We simply reuse the l_initfini list. */
+ imap->l_searchlist.r_list = &imap->l_initfini[cnt + 1];
+ imap->l_searchlist.r_nlist = cnt;
+
+ new_list = &imap->l_searchlist;
+ }
+
+ /* Count the number of scopes which remain after the unload.
+ When we add the local search list count it. Always add
+ one for the terminating NULL pointer. */
+ size_t remain = (new_list != NULL) + 1;
+ bool removed_any = false;
+ for (size_t cnt = 0; imap->l_scope[cnt] != NULL; ++cnt)
+ /* This relies on l_scope[] entries being always set either
+ to its own l_symbolic_searchlist address, or some map's
+ l_searchlist address. */
+ if (imap->l_scope[cnt] != &imap->l_symbolic_searchlist)
{
- /* Copy all later elements. */
- while ((runp[0] = runp[1]) != NULL)
- ++runp;
- break;
+ struct link_map *tmap = (struct link_map *)
+ ((char *) imap->l_scope[cnt]
+ - offsetof (struct link_map, l_searchlist));
+ assert (tmap->l_ns == nsid);
+ if (tmap->l_idx == IDX_STILL_USED)
+ ++remain;
+ else
+ removed_any = true;
}
- else
- ++runp;
+ else
+ ++remain;
+
+ if (removed_any)
+ {
+ /* Always allocate a new array for the scope. This is
+ necessary since we must be able to determine the last
+ user of the current array. If possible use the link map's
+ memory. */
+ size_t new_size;
+ struct r_scope_elem **newp;
+
+#define SCOPE_ELEMS(imap) \
+ (sizeof (imap->l_scope_mem) / sizeof (imap->l_scope_mem[0]))
+
+ if (imap->l_scope != imap->l_scope_mem
+ && remain < SCOPE_ELEMS (imap))
+ {
+ new_size = SCOPE_ELEMS (imap);
+ newp = imap->l_scope_mem;
+ }
+ else
+ {
+ new_size = imap->l_scope_max;
+ newp = (struct r_scope_elem **)
+ malloc (new_size * sizeof (struct r_scope_elem *));
+ if (newp == NULL)
+ _dl_signal_error (ENOMEM, "dlclose", NULL,
+ N_("cannot create scope list"));
+ }
+
+ /* Copy over the remaining scope elements. */
+ remain = 0;
+ for (size_t cnt = 0; imap->l_scope[cnt] != NULL; ++cnt)
+ {
+ if (imap->l_scope[cnt] != &imap->l_symbolic_searchlist)
+ {
+ struct link_map *tmap = (struct link_map *)
+ ((char *) imap->l_scope[cnt]
+ - offsetof (struct link_map, l_searchlist));
+ if (tmap->l_idx != IDX_STILL_USED)
+ {
+ /* Remove the scope. Or replace with own map's
+ scope. */
+ if (new_list != NULL)
+ {
+ newp[remain++] = new_list;
+ new_list = NULL;
+ }
+ continue;
+ }
+ }
+
+ newp[remain++] = imap->l_scope[cnt];
+ }
+ newp[remain] = NULL;
+
+ struct r_scope_elem **old = imap->l_scope;
+
+ imap->l_scope = newp;
+
+ /* No user anymore, we can free it now. */
+ if (old != imap->l_scope_mem)
+ {
+ if (_dl_scope_free (old))
+ /* If _dl_scope_free used THREAD_GSCOPE_WAIT (),
+ no need to repeat it. */
+ scope_mem_left = false;
+ }
+ else
+ scope_mem_left = true;
+
+ imap->l_scope_max = new_size;
+ }
+ else if (new_list != NULL)
+ {
+ /* We didn't change the scope array, so reset the search
+ list. */
+ imap->l_searchlist.r_list = NULL;
+ imap->l_searchlist.r_nlist = 0;
+ }
+
+ /* The loader is gone, so mark the object as not having one.
+ Note: l_idx != IDX_STILL_USED -> object will be removed. */
+ if (imap->l_loader != NULL
+ && imap->l_loader->l_idx != IDX_STILL_USED)
+ imap->l_loader = NULL;
+
+ /* Remember where the first dynamically loaded object is. */
+ if (i < first_loaded)
+ first_loaded = i;
}
+ }
- /* 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);
+ /* If there are no objects to unload, do nothing further. */
+ if (!unload_any)
+ goto out;
+
+#ifdef SHARED
+ /* Auditing checkpoint: we will start deleting objects. */
+ if (__glibc_unlikely (do_audit))
+ {
+ struct link_map *head = ns->_ns_loaded;
+ struct audit_ifaces *afct = GLRO(dl_audit);
+ /* Do not call the functions for any auditing object. */
+ if (head->l_auditing == 0)
+ {
+ for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
+ {
+ if (afct->activity != NULL)
+ afct->activity (&head->l_audit[cnt].cookie, LA_ACT_DELETE);
+
+ afct = afct->next;
+ }
+ }
}
+#endif
/* Notify the debugger we are about to remove some loaded objects. */
- _r_debug.r_state = RT_DELETE;
+ struct r_debug *r = _dl_debug_initialize (0, nsid);
+ r->r_state = RT_DELETE;
_dl_debug_state ();
+ LIBC_PROBE (unmap_start, 2, nsid, r);
-#ifdef USE_TLS
- size_t tls_free_start, tls_free_end;
- tls_free_start = tls_free_end = GL(dl_tls_static_used);
-#endif
+ if (unload_global)
+ {
+ /* Some objects are in the global scope list. Remove them. */
+ struct r_scope_elem *ns_msl = ns->_ns_main_searchlist;
+ unsigned int i;
+ unsigned int j = 0;
+ unsigned int cnt = ns_msl->r_nlist;
+
+ while (cnt > 0 && ns_msl->r_list[cnt - 1]->l_removed)
+ --cnt;
+
+ if (cnt + unload_global == ns_msl->r_nlist)
+ /* Speed up removing most recently added objects. */
+ j = cnt;
+ else
+ for (i = 0; i < cnt; i++)
+ if (ns_msl->r_list[i]->l_removed == 0)
+ {
+ if (i != j)
+ ns_msl->r_list[j] = ns_msl->r_list[i];
+ j++;
+ }
+ ns_msl->r_nlist = j;
+ }
+
+ if (!RTLD_SINGLE_THREAD_P
+ && (unload_global
+ || scope_mem_left
+ || (GL(dl_scope_free_list) != NULL
+ && GL(dl_scope_free_list)->count)))
+ {
+ THREAD_GSCOPE_WAIT ();
+
+ /* Now we can free any queued old scopes. */
+ struct dl_scope_free_list *fsl = GL(dl_scope_free_list);
+ if (fsl != NULL)
+ while (fsl->count > 0)
+ free (fsl->list[--fsl->count]);
+ }
+
+ size_t tls_free_start;
+ size_t tls_free_end;
+ tls_free_start = tls_free_end = NO_TLS_OFFSET;
+
+ /* We modify the list of loaded objects. */
+ __rtld_lock_lock_recursive (GL(dl_load_write_lock));
/* Check each element of the search list to see if all references to
it are gone. */
- for (i = 0; list[i] != NULL; ++i)
+ for (unsigned int i = first_loaded; i < nloaded; ++i)
{
- struct link_map *imap = list[i];
- if (imap->l_opencount == 0 && imap->l_type == lt_loaded)
+ struct link_map *imap = maps[i];
+ if (!used[i])
{
- struct libname_list *lnp;
+ assert (imap->l_type == lt_loaded);
/* 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. */
- unsigned int cnt = GL(dl_main_searchlist)->r_nlist;
-
- do
- --cnt;
- while (GL(dl_main_searchlist)->r_list[cnt] != imap);
-
- /* The object was already correctly registered. */
- while (++cnt < GL(dl_main_searchlist)->r_nlist)
- GL(dl_main_searchlist)->r_list[cnt - 1]
- = GL(dl_main_searchlist)->r_list[cnt];
-
- --GL(dl_main_searchlist)->r_nlist;
- }
-#ifdef USE_TLS
/* Remove the object from the dtv slotinfo array if it uses TLS. */
- if (__builtin_expect (imap->l_tls_blocksize > 0, 0))
+ if (__glibc_unlikely (imap->l_tls_blocksize > 0))
{
any_tls = true;
- if (! remove_slotinfo (imap->l_tls_modid,
- GL(dl_tls_dtv_slotinfo_list), 0,
- imap->l_init_called))
+ if (GL(dl_tls_dtv_slotinfo_list) != NULL
+ && ! remove_slotinfo (imap->l_tls_modid,
+ GL(dl_tls_dtv_slotinfo_list), 0,
+ imap->l_init_called))
/* All dynamically loaded modules with TLS are unloaded. */
GL(dl_tls_max_dtv_idx) = GL(dl_tls_static_nelem);
- if (imap->l_tls_offset != 0)
+ if (imap->l_tls_offset != NO_TLS_OFFSET
+ && imap->l_tls_offset != FORCED_DYNAMIC_TLS_OFFSET)
{
/* Collect a contiguous chunk built from the objects in
this search list, going in either direction. When the
whole chunk is at the end of the used area then we can
reclaim it. */
- if (imap->l_tls_offset == tls_free_end)
- /* Extend the contiguous chunk being reclaimed. */
- tls_free_end += imap->l_tls_blocksize;
- else if (imap->l_tls_offset + imap->l_tls_blocksize
- == tls_free_start)
+#if TLS_TCB_AT_TP
+ if (tls_free_start == NO_TLS_OFFSET
+ || (size_t) imap->l_tls_offset == tls_free_start)
+ {
+ /* Extend the contiguous chunk being reclaimed. */
+ tls_free_start
+ = imap->l_tls_offset - imap->l_tls_blocksize;
+
+ if (tls_free_end == NO_TLS_OFFSET)
+ tls_free_end = imap->l_tls_offset;
+ }
+ else if (imap->l_tls_offset - imap->l_tls_blocksize
+ == tls_free_end)
/* Extend the chunk backwards. */
- tls_free_start = imap->l_tls_offset;
+ tls_free_end = imap->l_tls_offset;
else
{
/* This isn't contiguous with the last chunk freed.
- One of them will be leaked. */
+ One of them will be leaked unless we can free
+ one block right away. */
if (tls_free_end == GL(dl_tls_static_used))
- GL(dl_tls_static_used) = tls_free_start;
- tls_free_start = imap->l_tls_offset;
- tls_free_end = tls_free_start + imap->l_tls_blocksize;
+ {
+ GL(dl_tls_static_used) = tls_free_start;
+ tls_free_end = imap->l_tls_offset;
+ tls_free_start
+ = tls_free_end - imap->l_tls_blocksize;
+ }
+ else if ((size_t) imap->l_tls_offset
+ == GL(dl_tls_static_used))
+ GL(dl_tls_static_used)
+ = imap->l_tls_offset - imap->l_tls_blocksize;
+ else if (tls_free_end < (size_t) imap->l_tls_offset)
+ {
+ /* We pick the later block. It has a chance to
+ be freed. */
+ tls_free_end = imap->l_tls_offset;
+ tls_free_start
+ = tls_free_end - imap->l_tls_blocksize;
+ }
+ }
+#elif TLS_DTV_AT_TP
+ if (tls_free_start == NO_TLS_OFFSET)
+ {
+ tls_free_start = imap->l_tls_firstbyte_offset;
+ tls_free_end = (imap->l_tls_offset
+ + imap->l_tls_blocksize);
+ }
+ else if (imap->l_tls_firstbyte_offset == tls_free_end)
+ /* Extend the contiguous chunk being reclaimed. */
+ tls_free_end = imap->l_tls_offset + imap->l_tls_blocksize;
+ else if (imap->l_tls_offset + imap->l_tls_blocksize
+ == tls_free_start)
+ /* Extend the chunk backwards. */
+ tls_free_start = imap->l_tls_firstbyte_offset;
+ /* This isn't contiguous with the last chunk freed.
+ One of them will be leaked unless we can free
+ one block right away. */
+ else if (imap->l_tls_offset + imap->l_tls_blocksize
+ == GL(dl_tls_static_used))
+ GL(dl_tls_static_used) = imap->l_tls_firstbyte_offset;
+ else if (tls_free_end == GL(dl_tls_static_used))
+ {
+ GL(dl_tls_static_used) = tls_free_start;
+ tls_free_start = imap->l_tls_firstbyte_offset;
+ tls_free_end = imap->l_tls_offset + imap->l_tls_blocksize;
+ }
+ else if (tls_free_end < imap->l_tls_firstbyte_offset)
+ {
+ /* We pick the later block. It has a chance to
+ be freed. */
+ tls_free_start = imap->l_tls_firstbyte_offset;
+ tls_free_end = imap->l_tls_offset + imap->l_tls_blocksize;
}
+#else
+# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
+#endif
}
}
-#endif
+
+ /* Reset unique symbols if forced. */
+ if (force)
+ {
+ struct unique_sym_table *tab = &ns->_ns_unique_sym_table;
+ __rtld_lock_lock_recursive (tab->lock);
+ struct unique_sym *entries = tab->entries;
+ if (entries != NULL)
+ {
+ size_t idx, size = tab->size;
+ for (idx = 0; idx < size; ++idx)
+ {
+ /* Clear unique symbol entries that belong to this
+ object. */
+ if (entries[idx].name != NULL
+ && entries[idx].map == imap)
+ {
+ entries[idx].name = NULL;
+ entries[idx].hashval = 0;
+ tab->n_elements--;
+ }
+ }
+ }
+ __rtld_lock_unlock_recursive (tab->lock);
+ }
/* We can unmap all the maps at once. We determined the
start address and length when we loaded the object and
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. */
+#if DL_NNS == 1
+ /* The assert in the (imap->l_prev == NULL) case gives
+ the compiler license to warn that NS points outside
+ the dl_ns array bounds in that case (as nsid != LM_ID_BASE
+ is tantamount to nsid >= DL_NNS). That should be impossible
+ in this configuration, so just assert about it instead. */
+ assert (nsid == LM_ID_BASE);
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;
+ if (imap->l_prev == NULL)
+ {
+ assert (nsid != LM_ID_BASE);
+ ns->_ns_loaded = imap->l_next;
+
+ /* Update the pointer to the head of the list
+ we leave for debuggers to examine. */
+ r->r_map = (void *) ns->_ns_loaded;
+ }
else
- GL(dl_loaded) = imap->l_next;
#endif
- --GL(dl_nloaded);
- if (imap->l_next)
+ imap->l_prev->l_next = imap->l_next;
+
+ --ns->_ns_nloaded;
+ if (imap->l_next != NULL)
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 (imap->l_versions);
+ if (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 = imap->l_reldeps;
- newrel->nrellist = imap->l_reldepsact;
- newrel->next = reldeps;
+ free (imap->l_reldeps);
- reldeps = newrel;
- }
+ /* Print debugging message. */
+ if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES))
+ _dl_debug_printf ("\nfile=%s [%lu]; destroying link map\n",
+ imap->l_name, imap->l_ns);
/* This name always is allocated. */
free (imap->l_name);
/* Remove the list with all the names of the shared object. */
- lnp = imap->l_libname;
+
+ struct libname_list *lnp = imap->l_libname;
do
{
struct libname_list *this = lnp;
while (lnp != NULL);
/* Remove the searchlists. */
- if (imap != map)
- free (imap->l_initfini);
+ free (imap->l_initfini);
/* Remove the scope array if we allocated it. */
if (imap->l_scope != imap->l_scope_mem)
}
}
-#ifdef USE_TLS
+ __rtld_lock_unlock_recursive (GL(dl_load_write_lock));
+
/* If we removed any object which uses TLS bump the generation counter. */
if (any_tls)
{
- if (__builtin_expect (++GL(dl_tls_generation) == 0, 0))
- __libc_fatal (_("TLS generation counter wrapped! Please send report with the 'glibcbug' script."));
+ if (__glibc_unlikely (++GL(dl_tls_generation) == 0))
+ _dl_fatal_printf ("TLS generation counter wrapped! Please report as described in "REPORT_BUGS_TO".\n");
if (tls_free_end == GL(dl_tls_static_used))
GL(dl_tls_static_used) = tls_free_start;
}
-#endif
- /* 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))
+#ifdef SHARED
+ /* Auditing checkpoint: we have deleted all objects. */
+ if (__glibc_unlikely (do_audit))
{
- while (reldeps->nrellist-- > 0)
- _dl_close (reldeps->rellist[reldeps->nrellist]);
-
- free (reldeps->rellist);
+ struct link_map *head = ns->_ns_loaded;
+ /* Do not call the functions for any auditing object. */
+ if (head->l_auditing == 0)
+ {
+ struct audit_ifaces *afct = GLRO(dl_audit);
+ for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
+ {
+ if (afct->activity != NULL)
+ afct->activity (&head->l_audit[cnt].cookie, LA_ACT_CONSISTENT);
- reldeps = reldeps->next;
+ afct = afct->next;
+ }
+ }
}
+#endif
- free (list);
-
- /* Release the lock. */
- __libc_lock_unlock_recursive (GL(dl_load_lock));
-}
-libc_hidden_def (_dl_close)
-
-
-#ifdef USE_TLS
-static bool
-free_slotinfo (struct dtv_slotinfo_list *elemp)
-{
- size_t cnt;
-
- if (elemp == NULL)
- /* Nothing here, all is removed (or there never was anything). */
- return true;
-
- if (!free_slotinfo (elemp->next))
- /* We cannot free the entry. */
- return false;
-
- /* The least we could do is remove next element (if there was any). */
- elemp->next = NULL;
+ if (__builtin_expect (ns->_ns_loaded == NULL, 0)
+ && nsid == GL(dl_nns) - 1)
+ do
+ --GL(dl_nns);
+ while (GL(dl_ns)[GL(dl_nns) - 1]._ns_loaded == NULL);
- for (cnt = 0; cnt < elemp->len; ++cnt)
- if (elemp->slotinfo[cnt].map != NULL)
- /* Still used. */
- return false;
+ /* Notify the debugger those objects are finalized and gone. */
+ r->r_state = RT_CONSISTENT;
+ _dl_debug_state ();
+ LIBC_PROBE (unmap_complete, 2, nsid, r);
- /* We can remove the list element. */
- free (elemp);
+ /* Recheck if we need to retry, release the lock. */
+ out:
+ if (dl_close_state == rerun)
+ goto retry;
- return true;
+ dl_close_state = not_pending;
}
-#endif
-libc_freeres_fn (free_mem)
+void
+_dl_close (void *_map)
{
- if (__builtin_expect (GL(dl_global_scope_alloc), 0) != 0
- && GL(dl_main_searchlist)->r_nlist == GL(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 = GL(dl_main_searchlist)->r_list;
+ struct link_map *map = _map;
- /* Put the old map in. */
- GL(dl_main_searchlist)->r_list = GL(dl_initial_searchlist).r_list;
- /* Signal that the original map is used. */
- GL(dl_global_scope_alloc) = 0;
+ /* We must take the lock to examine the contents of map and avoid
+ concurrent dlopens. */
+ __rtld_lock_lock_recursive (GL(dl_load_lock));
- /* Now free the old map. */
- free (old);
+ /* At this point we are guaranteed nobody else is touching the list of
+ loaded maps, but a concurrent dlclose might have freed our map
+ before we took the lock. There is no way to detect this (see below)
+ so we proceed assuming this isn't the case. First see whether we
+ can remove the object at all. */
+ if (__glibc_unlikely (map->l_flags_1 & DF_1_NODELETE))
+ {
+ /* Nope. Do nothing. */
+ __rtld_lock_unlock_recursive (GL(dl_load_lock));
+ return;
}
-#ifdef USE_TLS
- /* Free the memory allocated for the dtv slotinfo array. We can do
- this only if all modules which used this memory are unloaded.
- Also, the first element of the list does not have to be
- deallocated. It was allocated in the dynamic linker (i.e., with
- a different malloc). */
- if (free_slotinfo (GL(dl_tls_dtv_slotinfo_list)->next))
- GL(dl_tls_dtv_slotinfo_list)->next = NULL;
-#endif
+ /* At present this is an unreliable check except in the case where the
+ caller has recursively called dlclose and we are sure the link map
+ has not been freed. In a non-recursive dlclose the map itself
+ might have been freed and this access is potentially a data race
+ with whatever other use this memory might have now, or worse we
+ might silently corrupt memory if it looks enough like a link map.
+ POSIX has language in dlclose that appears to guarantee that this
+ should be a detectable case and given that dlclose should be threadsafe
+ we need this to be a reliable detection.
+ This is bug 20990. */
+ if (__builtin_expect (map->l_direct_opencount, 1) == 0)
+ {
+ __rtld_lock_unlock_recursive (GL(dl_load_lock));
+ _dl_signal_error (0, map->l_name, NULL, N_("shared object not open"));
+ }
+
+ _dl_close_worker (map, false);
+
+ __rtld_lock_unlock_recursive (GL(dl_load_lock));
}
projects / thirdparty / glibc.git / blobdiff