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191 lines
5.8 KiB
C
191 lines
5.8 KiB
C
/* Call the termination functions of loaded shared objects.
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Copyright (C) 1995,96,1998-2002,2004 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <alloca.h>
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#include <assert.h>
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#include <string.h>
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#include <ldsodefs.h>
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/* Type of the constructor functions. */
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typedef void (*fini_t) (void);
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void
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internal_function
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_dl_fini (void)
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{
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/* Lots of fun ahead. We have to call the destructors for all still
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loaded objects. The problem is that the ELF specification now
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demands that dependencies between the modules are taken into account.
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I.e., the destructor for a module is called before the ones for any
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of its dependencies.
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To make things more complicated, we cannot simply use the reverse
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order of the constructors. Since the user might have loaded objects
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using `dlopen' there are possibly several other modules with its
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dependencies to be taken into account. Therefore we have to start
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determining the order of the modules once again from the beginning. */
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unsigned int i;
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unsigned int nloaded;
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struct link_map *l;
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struct link_map **maps;
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/* Protect against concurrent loads and unloads. */
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__rtld_lock_lock_recursive (GL(dl_load_lock));
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nloaded = GL(dl_nloaded);
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/* XXX Could it be (in static binaries) that there is no object loaded? */
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assert (nloaded > 0);
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/* Now we can allocate an array to hold all the pointers and copy
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the pointers in. */
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maps = (struct link_map **) alloca (nloaded * sizeof (struct link_map *));
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for (l = GL(dl_loaded), i = 0; l != NULL; l = l->l_next)
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{
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assert (i < nloaded);
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maps[i++] = l;
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/* Bump l_opencount of all objects so that they are not dlclose()ed
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from underneath us. */
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++l->l_opencount;
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}
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assert (i == nloaded);
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/* Now we have to do the sorting. */
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for (l = GL(dl_loaded)->l_next; l != NULL; l = l->l_next)
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{
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unsigned int j;
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unsigned int k;
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/* Find the place in the 'maps' array. */
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for (j = 1; maps[j] != l; ++j)
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;
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/* Find all object for which the current one is a dependency and
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move the found object (if necessary) in front. */
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for (k = j + 1; k < nloaded; ++k)
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{
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struct link_map **runp = maps[k]->l_initfini;
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if (runp != NULL)
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{
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while (*runp != NULL)
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if (*runp == l)
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{
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struct link_map *here = maps[k];
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/* Move it now. */
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memmove (&maps[j] + 1,
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&maps[j],
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(k - j) * sizeof (struct link_map *));
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maps[j++] = here;
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break;
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}
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else
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++runp;
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}
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if (__builtin_expect (maps[k]->l_reldeps != NULL, 0))
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{
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unsigned int m = maps[k]->l_reldepsact;
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struct link_map **relmaps = maps[k]->l_reldeps;
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while (m-- > 0)
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{
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if (relmaps[m] == l)
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{
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struct link_map *here = maps[k];
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/* Move it now. */
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memmove (&maps[j] + 1,
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&maps[j],
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(k - j) * sizeof (struct link_map *));
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maps[j] = here;
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break;
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}
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}
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}
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}
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}
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/* We do not rely on the linked list of loaded object anymore from
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this point on. We have our own list here (maps). The various
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members of this list cannot vanish since the open count is too
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high and will be decremented in this loop. So we release the
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lock so that some code which might be called from a destructor
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can directly or indirectly access the lock. */
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__rtld_lock_unlock_recursive (GL(dl_load_lock));
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/* 'maps' now contains the objects in the right order. Now call the
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destructors. We have to process this array from the front. */
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for (i = 0; i < nloaded; ++i)
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{
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l = maps[i];
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if (l->l_init_called)
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{
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/* Make sure nothing happens if we are called twice. */
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l->l_init_called = 0;
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/* Don't call the destructors for objects we are not supposed to. */
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if (l->l_name[0] == '\0' && l->l_type == lt_executable)
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continue;
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/* Is there a destructor function? */
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if (l->l_info[DT_FINI_ARRAY] == NULL && l->l_info[DT_FINI] == NULL)
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continue;
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/* When debugging print a message first. */
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if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0))
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_dl_debug_printf ("\ncalling fini: %s\n\n",
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l->l_name[0] ? l->l_name : rtld_progname);
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/* First see whether an array is given. */
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if (l->l_info[DT_FINI_ARRAY] != NULL)
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{
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ElfW(Addr) *array =
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(ElfW(Addr) *) (l->l_addr
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+ l->l_info[DT_FINI_ARRAY]->d_un.d_ptr);
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unsigned int i = (l->l_info[DT_FINI_ARRAYSZ]->d_un.d_val
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/ sizeof (ElfW(Addr)));
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while (i-- > 0)
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((fini_t) array[i]) ();
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}
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/* Next try the old-style destructor. */
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if (l->l_info[DT_FINI] != NULL)
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((fini_t) DL_DT_FINI_ADDRESS (l, l->l_addr + l->l_info[DT_FINI]->d_un.d_ptr)) ();
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}
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/* Correct the previous increment. */
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--l->l_opencount;
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}
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if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_STATISTICS, 0))
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_dl_debug_printf ("\nruntime linker statistics:\n"
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" final number of relocations: %lu\n"
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"final number of relocations from cache: %lu\n",
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GL(dl_num_relocations),
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GL(dl_num_cache_relocations));
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}
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