| /* Call the termination functions of loaded shared objects. |
| Copyright (C) 1995-2016 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 Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 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 |
| 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, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <assert.h> |
| #include <string.h> |
| #include <ldsodefs.h> |
| |
| |
| /* Type of the constructor functions. */ |
| typedef void (*fini_t) (void); |
| |
| |
| void |
| internal_function |
| _dl_sort_fini (struct link_map **maps, size_t nmaps, char *used, Lmid_t ns) |
| { |
| /* A list of one element need not be sorted. */ |
| if (nmaps == 1) |
| return; |
| |
| /* We can skip looking for the binary itself which is at the front |
| of the search list for the main namespace. */ |
| unsigned int i = ns == LM_ID_BASE; |
| uint16_t seen[nmaps]; |
| memset (seen, 0, nmaps * sizeof (seen[0])); |
| while (1) |
| { |
| /* Keep track of which object we looked at this round. */ |
| ++seen[i]; |
| struct link_map *thisp = maps[i]; |
| |
| /* Do not handle ld.so in secondary namespaces and object which |
| are not removed. */ |
| if (thisp != thisp->l_real || thisp->l_idx == -1) |
| goto skip; |
| |
| /* Find the last object in the list for which the current one is |
| a dependency and move the current object behind the object |
| with the dependency. */ |
| unsigned int k = nmaps - 1; |
| while (k > i) |
| { |
| struct link_map **runp = maps[k]->l_initfini; |
| if (runp != NULL) |
| /* Look through the dependencies of the object. */ |
| while (*runp != NULL) |
| if (__glibc_unlikely (*runp++ == thisp)) |
| { |
| move: |
| /* Move the current object to the back past the last |
| object with it as the dependency. */ |
| memmove (&maps[i], &maps[i + 1], |
| (k - i) * sizeof (maps[0])); |
| maps[k] = thisp; |
| |
| if (used != NULL) |
| { |
| char here_used = used[i]; |
| memmove (&used[i], &used[i + 1], |
| (k - i) * sizeof (used[0])); |
| used[k] = here_used; |
| } |
| |
| if (seen[i + 1] > nmaps - i) |
| { |
| ++i; |
| goto next_clear; |
| } |
| |
| uint16_t this_seen = seen[i]; |
| memmove (&seen[i], &seen[i + 1], (k - i) * sizeof (seen[0])); |
| seen[k] = this_seen; |
| |
| goto next; |
| } |
| |
| if (__glibc_unlikely (maps[k]->l_reldeps != NULL)) |
| { |
| unsigned int m = maps[k]->l_reldeps->act; |
| struct link_map **relmaps = &maps[k]->l_reldeps->list[0]; |
| |
| /* Look through the relocation dependencies of the object. */ |
| while (m-- > 0) |
| if (__glibc_unlikely (relmaps[m] == thisp)) |
| { |
| /* If a cycle exists with a link time dependency, |
| preserve the latter. */ |
| struct link_map **runp = thisp->l_initfini; |
| if (runp != NULL) |
| while (*runp != NULL) |
| if (__glibc_unlikely (*runp++ == maps[k])) |
| goto ignore; |
| goto move; |
| } |
| ignore:; |
| } |
| |
| --k; |
| } |
| |
| skip: |
| if (++i == nmaps) |
| break; |
| next_clear: |
| memset (&seen[i], 0, (nmaps - i) * sizeof (seen[0])); |
| |
| next:; |
| } |
| } |
| |
| |
| void |
| internal_function |
| _dl_fini (void) |
| { |
| /* Lots of fun ahead. We have to call the destructors for all still |
| loaded objects, in all namespaces. The problem is that the ELF |
| specification now demands that dependencies between the modules |
| are taken into account. I.e., the destructor for a module is |
| called before the ones for any of its dependencies. |
| |
| To make things more complicated, we cannot simply use the reverse |
| order of the constructors. Since the user might have loaded objects |
| using `dlopen' there are possibly several other modules with its |
| dependencies to be taken into account. Therefore we have to start |
| determining the order of the modules once again from the beginning. */ |
| |
| /* We run the destructors of the main namespaces last. As for the |
| other namespaces, we pick run the destructors in them in reverse |
| order of the namespace ID. */ |
| #ifdef SHARED |
| int do_audit = 0; |
| again: |
| #endif |
| for (Lmid_t ns = GL(dl_nns) - 1; ns >= 0; --ns) |
| { |
| /* Protect against concurrent loads and unloads. */ |
| __rtld_lock_lock_recursive (GL(dl_load_lock)); |
| |
| unsigned int nloaded = GL(dl_ns)[ns]._ns_nloaded; |
| /* No need to do anything for empty namespaces or those used for |
| auditing DSOs. */ |
| if (nloaded == 0 |
| #ifdef SHARED |
| || GL(dl_ns)[ns]._ns_loaded->l_auditing != do_audit |
| #endif |
| ) |
| __rtld_lock_unlock_recursive (GL(dl_load_lock)); |
| else |
| { |
| /* Now we can allocate an array to hold all the pointers and |
| copy the pointers in. */ |
| struct link_map *maps[nloaded]; |
| |
| unsigned int i; |
| struct link_map *l; |
| assert (nloaded != 0 || GL(dl_ns)[ns]._ns_loaded == NULL); |
| for (l = GL(dl_ns)[ns]._ns_loaded, i = 0; l != NULL; l = l->l_next) |
| /* Do not handle ld.so in secondary namespaces. */ |
| if (l == l->l_real) |
| { |
| assert (i < nloaded); |
| |
| maps[i] = l; |
| l->l_idx = i; |
| ++i; |
| |
| /* Bump l_direct_opencount of all objects so that they |
| are not dlclose()ed from underneath us. */ |
| ++l->l_direct_opencount; |
| } |
| assert (ns != LM_ID_BASE || i == nloaded); |
| assert (ns == LM_ID_BASE || i == nloaded || i == nloaded - 1); |
| unsigned int nmaps = i; |
| |
| /* Now we have to do the sorting. */ |
| _dl_sort_fini (maps, nmaps, NULL, ns); |
| |
| /* We do not rely on the linked list of loaded object anymore |
| from this point on. We have our own list here (maps). The |
| various members of this list cannot vanish since the open |
| count is too high and will be decremented in this loop. So |
| we release the lock so that some code which might be called |
| from a destructor can directly or indirectly access the |
| lock. */ |
| __rtld_lock_unlock_recursive (GL(dl_load_lock)); |
| |
| /* 'maps' now contains the objects in the right order. Now |
| call the destructors. We have to process this array from |
| the front. */ |
| for (i = 0; i < nmaps; ++i) |
| { |
| struct link_map *l = maps[i]; |
| |
| if (l->l_init_called) |
| { |
| /* Make sure nothing happens if we are called twice. */ |
| l->l_init_called = 0; |
| |
| /* Is there a destructor function? */ |
| if (l->l_info[DT_FINI_ARRAY] != NULL |
| || l->l_info[DT_FINI] != NULL) |
| { |
| /* 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", |
| DSO_FILENAME (l->l_name), |
| ns); |
| |
| /* First see whether an array is given. */ |
| if (l->l_info[DT_FINI_ARRAY] != NULL) |
| { |
| ElfW(Addr) *array = |
| (ElfW(Addr) *) (l->l_addr |
| + l->l_info[DT_FINI_ARRAY]->d_un.d_ptr); |
| unsigned int i = (l->l_info[DT_FINI_ARRAYSZ]->d_un.d_val |
| / sizeof (ElfW(Addr))); |
| while (i-- > 0) |
| ((fini_t) array[i]) (); |
| } |
| |
| /* Next try the old-style destructor. */ |
| if (l->l_info[DT_FINI] != NULL) |
| DL_CALL_DT_FINI |
| (l, l->l_addr + l->l_info[DT_FINI]->d_un.d_ptr); |
| } |
| |
| #ifdef SHARED |
| /* Auditing checkpoint: another object closed. */ |
| if (!do_audit && __builtin_expect (GLRO(dl_naudit) > 0, 0)) |
| { |
| 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 (&l->l_audit[cnt].cookie); |
| |
| afct = afct->next; |
| } |
| } |
| #endif |
| } |
| |
| /* Correct the previous increment. */ |
| --l->l_direct_opencount; |
| } |
| } |
| } |
| |
| #ifdef SHARED |
| if (! do_audit && GLRO(dl_naudit) > 0) |
| { |
| do_audit = 1; |
| goto again; |
| } |
| |
| if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_STATISTICS)) |
| _dl_debug_printf ("\nruntime linker statistics:\n" |
| " final number of relocations: %lu\n" |
| "final number of relocations from cache: %lu\n", |
| GL(dl_num_relocations), |
| GL(dl_num_cache_relocations)); |
| #endif |
| } |