Annotation of gforth/libltdl/lt_dlloader.c, revision 1.1
1.1 ! anton 1: /* lt_dlloader.c -- dynamic library loader interface
! 2:
! 3: Copyright (C) 2004, 2007 Free Software Foundation, Inc.
! 4: Written by Gary V. Vaughan, 2004
! 5:
! 6: NOTE: The canonical source of this file is maintained with the
! 7: GNU Libtool package. Report bugs to bug-libtool@gnu.org.
! 8:
! 9: GNU Libltdl is free software; you can redistribute it and/or
! 10: modify it under the terms of the GNU Lesser General Public
! 11: License as published by the Free Software Foundation; either
! 12: version 2 of the License, or (at your option) any later version.
! 13:
! 14: As a special exception to the GNU Lesser General Public License,
! 15: if you distribute this file as part of a program or library that
! 16: is built using GNU Libtool, you may include this file under the
! 17: same distribution terms that you use for the rest of that program.
! 18:
! 19: GNU Libltdl is distributed in the hope that it will be useful,
! 20: but WITHOUT ANY WARRANTY; without even the implied warranty of
! 21: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
! 22: GNU Lesser General Public License for more details.
! 23:
! 24: You should have received a copy of the GNU Lesser General Public
! 25: License along with GNU Libltdl; see the file COPYING.LIB. If not, a
! 26: copy can be downloaded from http://www.gnu.org/licenses/lgpl.html,
! 27: or obtained by writing to the Free Software Foundation, Inc.,
! 28: 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
! 29: */
! 30:
! 31: #include "lt__private.h"
! 32: #include "lt_dlloader.h"
! 33:
! 34: #define RETURN_SUCCESS 0
! 35: #define RETURN_FAILURE 1
! 36:
! 37: static void * loader_callback (SList *item, void *userdata);
! 38:
! 39: /* A list of all the dlloaders we know about, each stored as a boxed
! 40: SList item: */
! 41: static SList *loaders = 0;
! 42:
! 43:
! 44: /* Return NULL, unless the loader in this ITEM has a matching name,
! 45: in which case we return the matching item so that its address is
! 46: passed back out (for possible freeing) by slist_remove. */
! 47: static void *
! 48: loader_callback (SList *item, void *userdata)
! 49: {
! 50: const lt_dlvtable *vtable = (const lt_dlvtable *) item->userdata;
! 51: const char * name = (const char *) userdata;
! 52:
! 53: assert (vtable);
! 54:
! 55: return streq (vtable->name, name) ? (void *) item : NULL;
! 56: }
! 57:
! 58:
! 59: /* Hook VTABLE into our global LOADERS list according to its own
! 60: PRIORITY field value. */
! 61: int
! 62: lt_dlloader_add (const lt_dlvtable *vtable)
! 63: {
! 64: SList *item;
! 65:
! 66: if ((vtable == 0) /* diagnose invalid vtable fields */
! 67: || (vtable->module_open == 0)
! 68: || (vtable->module_close == 0)
! 69: || (vtable->find_sym == 0)
! 70: || ((vtable->priority != LT_DLLOADER_PREPEND) &&
! 71: (vtable->priority != LT_DLLOADER_APPEND)))
! 72: {
! 73: LT__SETERROR (INVALID_LOADER);
! 74: return RETURN_FAILURE;
! 75: }
! 76:
! 77: item = slist_box (vtable);
! 78: if (!item)
! 79: {
! 80: (*lt__alloc_die) ();
! 81:
! 82: /* Let the caller know something went wrong if lt__alloc_die
! 83: doesn't abort. */
! 84: return RETURN_FAILURE;
! 85: }
! 86:
! 87: if (vtable->priority == LT_DLLOADER_PREPEND)
! 88: {
! 89: loaders = slist_cons (item, loaders);
! 90: }
! 91: else
! 92: {
! 93: assert (vtable->priority == LT_DLLOADER_APPEND);
! 94: loaders = slist_concat (loaders, item);
! 95: }
! 96:
! 97: return RETURN_SUCCESS;
! 98: }
! 99:
! 100: #ifdef LT_DEBUG_LOADERS
! 101: static void *
! 102: loader_dump_callback (SList *item, void *userdata)
! 103: {
! 104: const lt_dlvtable *vtable = (const lt_dlvtable *) item->userdata;
! 105: fprintf (stderr, ", %s", (vtable && vtable->name) ? vtable->name : "(null)");
! 106: return 0;
! 107: }
! 108:
! 109: void
! 110: lt_dlloader_dump (void)
! 111: {
! 112: fprintf (stderr, "loaders: ");
! 113: if (!loaders)
! 114: {
! 115: fprintf (stderr, "(empty)");
! 116: }
! 117: else
! 118: {
! 119: const lt_dlvtable *head = (const lt_dlvtable *) loaders->userdata;
! 120: fprintf (stderr, "%s", (head && head->name) ? head->name : "(null)");
! 121: if (slist_tail (loaders))
! 122: slist_foreach (slist_tail (loaders), loader_dump_callback, NULL);
! 123: }
! 124: fprintf (stderr, "\n");
! 125: }
! 126: #endif
! 127:
! 128: /* An iterator for the global loader list: if LOADER is NULL, then
! 129: return the first element, otherwise the following element. */
! 130: lt_dlloader
! 131: lt_dlloader_next (lt_dlloader loader)
! 132: {
! 133: SList *item = (SList *) loader;
! 134: return (lt_dlloader) (item ? item->next : loaders);
! 135: }
! 136:
! 137:
! 138: /* Non-destructive unboxing of a loader. */
! 139: const lt_dlvtable *
! 140: lt_dlloader_get (lt_dlloader loader)
! 141: {
! 142: return (const lt_dlvtable *) (loader ? ((SList *) loader)->userdata : NULL);
! 143: }
! 144:
! 145:
! 146: /* Return the contents of the first item in the global loader list
! 147: with a matching NAME after removing it from that list. If there
! 148: was no match, return NULL; if there is an error, return NULL and
! 149: set an error for lt_dlerror; do not set an error if only resident
! 150: modules need this loader; in either case, the loader list is not
! 151: changed if NULL is returned. */
! 152: lt_dlvtable *
! 153: lt_dlloader_remove (char *name)
! 154: {
! 155: const lt_dlvtable * vtable = lt_dlloader_find (name);
! 156: static const char id_string[] = "lt_dlloader_remove";
! 157: lt_dlinterface_id iface;
! 158: lt_dlhandle handle = 0;
! 159: int in_use = 0;
! 160: int in_use_by_resident = 0;
! 161:
! 162: if (!vtable)
! 163: {
! 164: LT__SETERROR (INVALID_LOADER);
! 165: return 0;
! 166: }
! 167:
! 168: /* Fail if there are any open modules which use this loader. */
! 169: iface = lt_dlinterface_register (id_string, NULL);
! 170: while ((handle = lt_dlhandle_iterate (iface, handle)))
! 171: {
! 172: lt__handle *cur = (lt__handle *) handle;
! 173: if (cur->vtable == vtable)
! 174: {
! 175: in_use = 1;
! 176: if (lt_dlisresident (handle))
! 177: in_use_by_resident = 1;
! 178: }
! 179: }
! 180: lt_dlinterface_free (iface);
! 181: if (in_use)
! 182: {
! 183: if (!in_use_by_resident)
! 184: LT__SETERROR (REMOVE_LOADER);
! 185: return 0;
! 186: }
! 187:
! 188: /* Call the loader finalisation function. */
! 189: if (vtable && vtable->dlloader_exit)
! 190: {
! 191: if ((*vtable->dlloader_exit) (vtable->dlloader_data) != 0)
! 192: {
! 193: /* If there is an exit function, and it returns non-zero
! 194: then it must set an error, and we will not remove it
! 195: from the list. */
! 196: return 0;
! 197: }
! 198: }
! 199:
! 200: /* If we got this far, remove the loader from our global list. */
! 201: return (lt_dlvtable *)
! 202: slist_unbox ((SList *) slist_remove (&loaders, loader_callback, name));
! 203: }
! 204:
! 205:
! 206: const lt_dlvtable *
! 207: lt_dlloader_find (char *name)
! 208: {
! 209: return lt_dlloader_get (slist_find (loaders, loader_callback, name));
! 210: }
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