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/* lt_dlloader.c -- dynamic library loader interface
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Copyright (C) 2004, 2007, 2008 Free Software Foundation, Inc.
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Written by Gary V. Vaughan, 2004
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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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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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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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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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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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#include "lt__private.h"
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#include "lt_dlloader.h"
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#define RETURN_SUCCESS 0
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#define RETURN_FAILURE 1
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static void * loader_callback (SList *item, void *userdata);
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/* A list of all the dlloaders we know about, each stored as a boxed
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static SList *loaders = 0;
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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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loader_callback (SList *item, void *userdata)
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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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return streq (vtable->name, name) ? (void *) item : NULL;
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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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lt_dlloader_add (const lt_dlvtable *vtable)
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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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LT__SETERROR (INVALID_LOADER);
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return RETURN_FAILURE;
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item = slist_box (vtable);
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/* Let the caller know something went wrong if lt__alloc_die
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return RETURN_FAILURE;
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if (vtable->priority == LT_DLLOADER_PREPEND)
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loaders = slist_cons (item, loaders);
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assert (vtable->priority == LT_DLLOADER_APPEND);
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loaders = slist_concat (loaders, item);
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return RETURN_SUCCESS;
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#ifdef LT_DEBUG_LOADERS
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loader_dump_callback (SList *item, void *userdata)
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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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lt_dlloader_dump (void)
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fprintf (stderr, "loaders: ");
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fprintf (stderr, "(empty)");
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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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fprintf (stderr, "\n");
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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_next (lt_dlloader loader)
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SList *item = (SList *) loader;
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return (lt_dlloader) (item ? item->next : loaders);
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/* Non-destructive unboxing of a loader. */
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lt_dlloader_get (lt_dlloader loader)
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return (const lt_dlvtable *) (loader ? ((SList *) loader)->userdata : NULL);
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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_dlloader_remove (const char *name)
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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_by_resident = 0;
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LT__SETERROR (INVALID_LOADER);
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/* Fail if there are any open modules which 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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lt_dlhandle cur = handle;
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if (cur->vtable == vtable)
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if (lt_dlisresident (handle))
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in_use_by_resident = 1;
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lt_dlinterface_free (iface);
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if (!in_use_by_resident)
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LT__SETERROR (REMOVE_LOADER);
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/* Call the loader finalisation function. */
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if (vtable && vtable->dlloader_exit)
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if ((*vtable->dlloader_exit) (vtable->dlloader_data) != 0)
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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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/* 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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lt_dlloader_find (const char *name)
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return lt_dlloader_get (slist_find (loaders, loader_callback, (void *) name));
added
removed
libltdl/lt_dlloader.c
