diff options
Diffstat (limited to 'elf/dl-close.c')
| -rw-r--r-- | elf/dl-close.c | 148 |
1 files changed, 112 insertions, 36 deletions
diff --git a/elf/dl-close.c b/elf/dl-close.c index 6a2ad976a7..2e7c506a3d 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> @@ -35,6 +36,10 @@ 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 +193,7 @@ _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 +201,7 @@ _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 +222,7 @@ _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 +315,9 @@ _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 +334,114 @@ _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_scope[cnt] == &map->l_searchlist) + if (imap->l_scoperec->scope[cnt] + != &imap->l_symbolic_searchlist) { - while ((imap->l_scope[cnt] = imap->l_scope[cnt + 1]) - != NULL) - ++cnt; - break; + 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; + } } - ++cnt; + + newp->scope[remain++] = imap->l_scoperec->scope[cnt]; } + newp->scope[remain] = NULL; + + struct r_scoperec *old = imap->l_scoperec; + + __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) + { + old->remove_after_use = true; + old->notify = true; + if (atomic_decrement_val (&old->nusers) != 0) + __rtld_waitzero (old->nusers); + } + + /* 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 +646,8 @@ _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); |