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/* lt_dlloader.c -- dynamic library loader interface |
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|
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Copyright (C) 2004, 2007-2008, 2011-2015 Free Software Foundation, |
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Inc. |
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Written by Gary V. Vaughan, 2004 |
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|
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NOTE: The canonical source of this file is maintained with the |
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GNU Libtool package. Report bugs to bug-libtool@gnu.org. |
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|
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GNU Libltdl 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 of the License, or (at your option) any later version. |
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|
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As a special exception to the GNU Lesser General Public License, |
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if you distribute this file as part of a program or library that |
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is built using GNU Libtool, you may include this file under the |
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same distribution terms that you use for the rest of that program. |
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|
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GNU Libltdl 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 |
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GNU Lesser General Public License for more details. |
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|
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You should have received a copy of the GNU Lesser General Public |
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License along with GNU Libltdl; see the file COPYING.LIB. If not, a |
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copy can be downloaded from http://www.gnu.org/licenses/lgpl.html, |
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or obtained by writing to the Free Software Foundation, Inc., |
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
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*/ |
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|
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#include "lt__private.h" |
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#include "lt_dlloader.h" |
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|
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#define RETURN_SUCCESS 0 |
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#define RETURN_FAILURE 1 |
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|
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static void * loader_callback (SList *item, void *userdata); |
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|
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/* A list of all the dlloaders we know about, each stored as a boxed |
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SList item: */ |
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static SList *loaders = 0; |
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|
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|
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/* Return NULL, unless the loader in this ITEM has a matching name, |
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in which case we return the matching item so that its address is |
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passed back out (for possible freeing) by slist_remove. */ |
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static void * |
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loader_callback (SList *item, void *userdata) |
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{ |
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const lt_dlvtable *vtable = (const lt_dlvtable *) item->userdata; |
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const char * name = (const char *) userdata; |
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|
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assert (vtable); |
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|
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return STREQ (vtable->name, name) ? (void *) item : NULL; |
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} |
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|
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|
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/* Hook VTABLE into our global LOADERS list according to its own |
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PRIORITY field value. */ |
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int |
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lt_dlloader_add (const lt_dlvtable *vtable) |
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{ |
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SList *item; |
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|
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if ((vtable == 0) /* diagnose invalid vtable fields */ |
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|| (vtable->module_open == 0) |
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|| (vtable->module_close == 0) |
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|| (vtable->find_sym == 0) |
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|| ((vtable->priority != LT_DLLOADER_PREPEND) && |
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(vtable->priority != LT_DLLOADER_APPEND))) |
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{ |
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LT__SETERROR (INVALID_LOADER); |
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return RETURN_FAILURE; |
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} |
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|
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item = slist_box (vtable); |
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if (!item) |
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{ |
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(*lt__alloc_die) (); |
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|
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/* Let the caller know something went wrong if lt__alloc_die |
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doesn't abort. */ |
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return RETURN_FAILURE; |
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} |
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|
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if (vtable->priority == LT_DLLOADER_PREPEND) |
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{ |
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loaders = slist_cons (item, loaders); |
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} |
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else |
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{ |
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assert (vtable->priority == LT_DLLOADER_APPEND); |
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loaders = slist_concat (loaders, item); |
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} |
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|
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return RETURN_SUCCESS; |
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} |
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|
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#ifdef LT_DEBUG_LOADERS |
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static void * |
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loader_dump_callback (SList *item, void *userdata) |
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{ |
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const lt_dlvtable *vtable = (const lt_dlvtable *) item->userdata; |
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fprintf (stderr, ", %s", (vtable && vtable->name) ? vtable->name : "(null)"); |
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return 0; |
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} |
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|
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void |
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lt_dlloader_dump (void) |
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{ |
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fprintf (stderr, "loaders: "); |
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if (!loaders) |
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{ |
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fprintf (stderr, "(empty)"); |
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} |
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else |
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{ |
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const lt_dlvtable *head = (const lt_dlvtable *) loaders->userdata; |
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fprintf (stderr, "%s", (head && head->name) ? head->name : "(null)"); |
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if (slist_tail (loaders)) |
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slist_foreach (slist_tail (loaders), loader_dump_callback, NULL); |
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} |
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fprintf (stderr, "\n"); |
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} |
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#endif |
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|
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/* An iterator for the global loader list: if LOADER is NULL, then |
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return the first element, otherwise the following element. */ |
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lt_dlloader |
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lt_dlloader_next (lt_dlloader loader) |
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{ |
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SList *item = (SList *) loader; |
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return (lt_dlloader) (item ? item->next : loaders); |
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} |
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|
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|
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/* Non-destructive unboxing of a loader. */ |
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const lt_dlvtable * |
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lt_dlloader_get (lt_dlloader loader) |
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{ |
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return (const lt_dlvtable *) (loader ? ((SList *) loader)->userdata : NULL); |
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} |
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|
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|
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/* Return the contents of the first item in the global loader list |
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with a matching NAME after removing it from that list. If there |
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was no match, return NULL; if there is an error, return NULL and |
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set an error for lt_dlerror; do not set an error if only resident |
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modules need this loader; in either case, the loader list is not |
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changed if NULL is returned. */ |
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lt_dlvtable * |
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lt_dlloader_remove (const char *name) |
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{ |
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const lt_dlvtable * vtable = lt_dlloader_find (name); |
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static const char id_string[] = "lt_dlloader_remove"; |
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lt_dlinterface_id iface; |
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lt_dlhandle handle = 0; |
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int in_use = 0; |
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int in_use_by_resident = 0; |
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|
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if (!vtable) |
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{ |
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LT__SETERROR (INVALID_LOADER); |
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return 0; |
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} |
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|
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/* Fail if there are any open modules that use this loader. */ |
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iface = lt_dlinterface_register (id_string, NULL); |
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while ((handle = lt_dlhandle_iterate (iface, handle))) |
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{ |
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lt_dlhandle cur = handle; |
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if (cur->vtable == vtable) |
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{ |
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in_use = 1; |
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if (lt_dlisresident (handle)) |
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in_use_by_resident = 1; |
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} |
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} |
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lt_dlinterface_free (iface); |
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if (in_use) |
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{ |
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if (!in_use_by_resident) |
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LT__SETERROR (REMOVE_LOADER); |
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return 0; |
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} |
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|
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/* Call the loader finalisation function. */ |
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if (vtable && vtable->dlloader_exit) |
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{ |
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if ((*vtable->dlloader_exit) (vtable->dlloader_data) != 0) |
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{ |
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/* If there is an exit function, and it returns non-zero |
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then it must set an error, and we will not remove it |
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from the list. */ |
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return 0; |
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} |
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} |
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|
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/* If we got this far, remove the loader from our global list. */ |
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return (lt_dlvtable *) |
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slist_unbox ((SList *) slist_remove (&loaders, loader_callback, (void *) name)); |
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} |
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|
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|
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const lt_dlvtable * |
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lt_dlloader_find (const char *name) |
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{ |
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return lt_dlloader_get (slist_find (loaders, loader_callback, (void *) name)); |
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} |