cristy | 3ed852e | 2009-09-05 21:47:34 +0000 | [diff] [blame] | 1 | /* lt_dlloader.c -- dynamic library loader interface |
| 2 | |
| 3 | Copyright (C) 2004, 2007, 2008 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 |
cristy | cee9711 | 2010-05-28 00:44:52 +0000 | [diff] [blame] | 25 | License along with GNU Libltdl; see the file COPYING.LIB. If not, a |
cristy | 3ed852e | 2009-09-05 21:47:34 +0000 | [diff] [blame] | 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 * |
cristy | 98dddb5 | 2010-11-04 00:30:15 +0000 | [diff] [blame] | 153 | lt_dlloader_remove (const char *name) |
cristy | 3ed852e | 2009-09-05 21:47:34 +0000 | [diff] [blame] | 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_dlhandle cur = 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 *) |
cristy | 98dddb5 | 2010-11-04 00:30:15 +0000 | [diff] [blame] | 202 | slist_unbox ((SList *) slist_remove (&loaders, loader_callback, (void *) name)); |
cristy | 3ed852e | 2009-09-05 21:47:34 +0000 | [diff] [blame] | 203 | } |
| 204 | |
| 205 | |
| 206 | const lt_dlvtable * |
cristy | 98dddb5 | 2010-11-04 00:30:15 +0000 | [diff] [blame] | 207 | lt_dlloader_find (const char *name) |
cristy | 3ed852e | 2009-09-05 21:47:34 +0000 | [diff] [blame] | 208 | { |
cristy | 98dddb5 | 2010-11-04 00:30:15 +0000 | [diff] [blame] | 209 | return lt_dlloader_get (slist_find (loaders, loader_callback, (void *) name)); |
cristy | 3ed852e | 2009-09-05 21:47:34 +0000 | [diff] [blame] | 210 | } |