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Diffstat (limited to 'elf/dl-close.c')
-rw-r--r--elf/dl-close.c154
1 files changed, 118 insertions, 36 deletions
diff --git a/elf/dl-close.c b/elf/dl-close.c
index 6a2ad976a7..bfcceea4bc 100644
--- a/elf/dl-close.c
+++ b/elf/dl-close.c
@@ -19,6 +19,7 @@
#include <assert.h>
#include <dlfcn.h>
+#include <errno.h>
#include <libintl.h>
#include <stddef.h>
#include <stdio.h>
@@ -29,12 +30,17 @@
#include <ldsodefs.h>
#include <sys/types.h>
#include <sys/mman.h>
+#include <sysdep-cancel.h>
/* Type of the constructor functions. */
typedef void (*fini_t) (void);
+/* Special l_idx value used to indicate which objects remain loaded. */
+#define IDX_STILL_USED -1
+
+
#ifdef USE_TLS
/* Returns true we an non-empty was found. */
static bool
@@ -188,7 +194,7 @@ _dl_close (void *_map)
done[done_index] = 1;
used[done_index] = 1;
/* Signal the object is still needed. */
- l->l_idx = -1;
+ l->l_idx = IDX_STILL_USED;
/* Mark all dependencies as used. */
if (l->l_initfini != NULL)
@@ -196,7 +202,7 @@ _dl_close (void *_map)
struct link_map **lp = &l->l_initfini[1];
while (*lp != NULL)
{
- if ((*lp)->l_idx != -1)
+ if ((*lp)->l_idx != IDX_STILL_USED)
{
assert ((*lp)->l_idx >= 0 && (*lp)->l_idx < nloaded);
@@ -217,7 +223,7 @@ _dl_close (void *_map)
{
struct link_map *jmap = l->l_reldeps[j];
- if (jmap->l_idx != -1)
+ if (jmap->l_idx != IDX_STILL_USED)
{
assert (jmap->l_idx >= 0 && jmap->l_idx < nloaded);
@@ -310,8 +316,9 @@ _dl_close (void *_map)
/* Else used[i]. */
else if (imap->l_type == lt_loaded)
{
- if (imap->l_searchlist.r_list == NULL
- && imap->l_initfini != NULL)
+ 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
@@ -328,44 +335,119 @@ _dl_close (void *_map)
imap->l_searchlist.r_list = &imap->l_initfini[cnt + 1];
imap->l_searchlist.r_nlist = cnt;
- for (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)
- {
- struct link_map *tmap;
-
- tmap = (struct link_map *) ((char *) imap->l_scope[cnt]
- - offsetof (struct link_map,
- l_searchlist));
- assert (tmap->l_ns == ns);
- if (tmap->l_idx != -1)
- {
- imap->l_scope[cnt] = &imap->l_searchlist;
- break;
- }
- }
+ new_list = &imap->l_searchlist;
}
- else
+
+ /* 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_scoperec->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_scoperec->scope[cnt] != &imap->l_symbolic_searchlist)
+ {
+ struct link_map *tmap = (struct link_map *)
+ ((char *) imap->l_scoperec->scope[cnt]
+ - offsetof (struct link_map, l_searchlist));
+ assert (tmap->l_ns == ns);
+ if (tmap->l_idx == IDX_STILL_USED)
+ ++remain;
+ else
+ removed_any = true;
+ }
+ else
+ ++remain;
+
+ if (removed_any)
{
- unsigned int cnt = 0;
- while (imap->l_scope[cnt] != NULL)
+ /* 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_scoperec *newp;
+ if (imap->l_scoperec != &imap->l_scoperec_mem
+ && remain < NINIT_SCOPE_ELEMS (imap)
+ && imap->l_scoperec_mem.nusers == 0)
+ {
+ new_size = NINIT_SCOPE_ELEMS (imap);
+ newp = &imap->l_scoperec_mem;
+ }
+ else
+ {
+ new_size = imap->l_scope_max;
+ newp = (struct r_scoperec *)
+ malloc (sizeof (struct r_scoperec)
+ + new_size * sizeof (struct r_scope_elem *));
+ if (newp == NULL)
+ _dl_signal_error (ENOMEM, "dlclose", NULL,
+ N_("cannot create scope list"));
+ }
+
+ newp->nusers = 0;
+ newp->remove_after_use = false;
+ newp->notify = false;
+
+ /* Copy over the remaining scope elements. */
+ remain = 0;
+ for (size_t cnt = 0; imap->l_scoperec->scope[cnt] != NULL; ++cnt)
+ {
+ if (imap->l_scoperec->scope[cnt]
+ != &imap->l_symbolic_searchlist)
+ {
+ struct link_map *tmap = (struct link_map *)
+ ((char *) imap->l_scoperec->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->scope[remain++] = new_list;
+ new_list = NULL;
+ }
+ continue;
+ }
+ }
+
+ newp->scope[remain++] = imap->l_scoperec->scope[cnt];
+ }
+ newp->scope[remain] = NULL;
+
+ struct r_scoperec *old = imap->l_scoperec;
+
+ if (SINGLE_THREAD_P)
+ imap->l_scoperec = newp;
+ else
{
- if (imap->l_scope[cnt] == &map->l_searchlist)
+ __rtld_mrlock_change (imap->l_scoperec_lock);
+ imap->l_scoperec = newp;
+ __rtld_mrlock_done (imap->l_scoperec_lock);
+
+ if (atomic_increment_val (&old->nusers) != 1)
{
- while ((imap->l_scope[cnt] = imap->l_scope[cnt + 1])
- != NULL)
- ++cnt;
- break;
+ old->remove_after_use = true;
+ old->notify = true;
+ if (atomic_decrement_val (&old->nusers) != 0)
+ __rtld_waitzero (old->nusers);
}
- ++cnt;
}
+
+ /* No user anymore, we can free it now. */
+ if (old != &imap->l_scoperec_mem)
+ free (old);
+
+ imap->l_scope_max = new_size;
}
/* The loader is gone, so mark the object as not having one.
- Note: l_idx != -1 -> object will be removed. */
- if (imap->l_loader != NULL && imap->l_loader->l_idx != -1)
+ 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. */
@@ -570,8 +652,8 @@ _dl_close (void *_map)
free (imap->l_initfini);
/* Remove the scope array if we allocated it. */
- if (imap->l_scope != imap->l_scope_mem)
- free (imap->l_scope);
+ if (imap->l_scoperec != &imap->l_scoperec_mem)
+ free (imap->l_scoperec);
if (imap->l_phdr_allocated)
free ((void *) imap->l_phdr);
generated by cgit v1.2.3 (git 2.39.1) at 2024-04-28 08:34:23 +0000