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 9GNU Libltdl is free software; you can redistribute it and/or 10modify it under the terms of the GNU Lesser General Public 11License as published by the Free Software Foundation; either 12version 2 of the License, or (at your option) any later version. 13 14As a special exception to the GNU Lesser General Public License, 15if you distribute this file as part of a program or library that 16is built using GNU Libtool, you may include this file under the 17same distribution terms that you use for the rest of that program. 18 19GNU Libltdl is distributed in the hope that it will be useful, 20but WITHOUT ANY WARRANTY; without even the implied warranty of 21MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 22GNU Lesser General Public License for more details. 23 24You should have received a copy of the GNU Lesser General Public 25License along with GNU Libltdl; see the file COPYING.LIB. If not, a 26copy can be downloaded from http://www.gnu.org/licenses/lgpl.html, 27or obtained by writing to the Free Software Foundation, Inc., 2851 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 37static 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: */ 41static 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. */ 47static void * 48loader_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. */ 61int 62lt_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 101static void * 102loader_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 109void 110lt_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. */ 130lt_dlloader 131lt_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. */ 139const lt_dlvtable * 140lt_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. */ 152lt_dlvtable * 153lt_dlloader_remove (const 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_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 *) 202 slist_unbox ((SList *) slist_remove (&loaders, loader_callback, (void *) name)); 203} 204 205 206const lt_dlvtable * 207lt_dlloader_find (const char *name) 208{ 209 return lt_dlloader_get (slist_find (loaders, loader_callback, (void *) name)); 210} 211