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Revision 5394 - (show annotations)
Tue Jan 20 14:03:09 2015 UTC (7 years, 10 months ago) by michael
File MIME type: text/x-chdr
File size: 6088 byte(s)
- libtool 2.4.5, automake 1.15

1 /* lt_dlloader.c -- dynamic library loader interface
2
3 Copyright (C) 2004, 2007-2008, 2011-2015 Free Software Foundation,
4 Inc.
5 Written by Gary V. Vaughan, 2004
6
7 NOTE: The canonical source of this file is maintained with the
8 GNU Libtool package. Report bugs to bug-libtool@gnu.org.
9
10 GNU Libltdl is free software; you can redistribute it and/or
11 modify it under the terms of the GNU Lesser General Public
12 License as published by the Free Software Foundation; either
13 version 2 of the License, or (at your option) any later version.
14
15 As a special exception to the GNU Lesser General Public License,
16 if you distribute this file as part of a program or library that
17 is built using GNU Libtool, you may include this file under the
18 same distribution terms that you use for the rest of that program.
19
20 GNU Libltdl is distributed in the hope that it will be useful,
21 but WITHOUT ANY WARRANTY; without even the implied warranty of
22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23 GNU Lesser General Public License for more details.
24
25 You should have received a copy of the GNU Lesser General Public
26 License along with GNU Libltdl; see the file COPYING.LIB. If not, a
27 copy can be downloaded from http://www.gnu.org/licenses/lgpl.html,
28 or obtained by writing to the Free Software Foundation, Inc.,
29 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
30 */
31
32 #include "lt__private.h"
33 #include "lt_dlloader.h"
34
35 #define RETURN_SUCCESS 0
36 #define RETURN_FAILURE 1
37
38 static void * loader_callback (SList *item, void *userdata);
39
40 /* A list of all the dlloaders we know about, each stored as a boxed
41 SList item: */
42 static SList *loaders = 0;
43
44
45 /* Return NULL, unless the loader in this ITEM has a matching name,
46 in which case we return the matching item so that its address is
47 passed back out (for possible freeing) by slist_remove. */
48 static void *
49 loader_callback (SList *item, void *userdata)
50 {
51 const lt_dlvtable *vtable = (const lt_dlvtable *) item->userdata;
52 const char * name = (const char *) userdata;
53
54 assert (vtable);
55
56 return STREQ (vtable->name, name) ? (void *) item : NULL;
57 }
58
59
60 /* Hook VTABLE into our global LOADERS list according to its own
61 PRIORITY field value. */
62 int
63 lt_dlloader_add (const lt_dlvtable *vtable)
64 {
65 SList *item;
66
67 if ((vtable == 0) /* diagnose invalid vtable fields */
68 || (vtable->module_open == 0)
69 || (vtable->module_close == 0)
70 || (vtable->find_sym == 0)
71 || ((vtable->priority != LT_DLLOADER_PREPEND) &&
72 (vtable->priority != LT_DLLOADER_APPEND)))
73 {
74 LT__SETERROR (INVALID_LOADER);
75 return RETURN_FAILURE;
76 }
77
78 item = slist_box (vtable);
79 if (!item)
80 {
81 (*lt__alloc_die) ();
82
83 /* Let the caller know something went wrong if lt__alloc_die
84 doesn't abort. */
85 return RETURN_FAILURE;
86 }
87
88 if (vtable->priority == LT_DLLOADER_PREPEND)
89 {
90 loaders = slist_cons (item, loaders);
91 }
92 else
93 {
94 assert (vtable->priority == LT_DLLOADER_APPEND);
95 loaders = slist_concat (loaders, item);
96 }
97
98 return RETURN_SUCCESS;
99 }
100
101 #ifdef LT_DEBUG_LOADERS
102 static void *
103 loader_dump_callback (SList *item, void *userdata)
104 {
105 const lt_dlvtable *vtable = (const lt_dlvtable *) item->userdata;
106 fprintf (stderr, ", %s", (vtable && vtable->name) ? vtable->name : "(null)");
107 return 0;
108 }
109
110 void
111 lt_dlloader_dump (void)
112 {
113 fprintf (stderr, "loaders: ");
114 if (!loaders)
115 {
116 fprintf (stderr, "(empty)");
117 }
118 else
119 {
120 const lt_dlvtable *head = (const lt_dlvtable *) loaders->userdata;
121 fprintf (stderr, "%s", (head && head->name) ? head->name : "(null)");
122 if (slist_tail (loaders))
123 slist_foreach (slist_tail (loaders), loader_dump_callback, NULL);
124 }
125 fprintf (stderr, "\n");
126 }
127 #endif
128
129 /* An iterator for the global loader list: if LOADER is NULL, then
130 return the first element, otherwise the following element. */
131 lt_dlloader
132 lt_dlloader_next (lt_dlloader loader)
133 {
134 SList *item = (SList *) loader;
135 return (lt_dlloader) (item ? item->next : loaders);
136 }
137
138
139 /* Non-destructive unboxing of a loader. */
140 const lt_dlvtable *
141 lt_dlloader_get (lt_dlloader loader)
142 {
143 return (const lt_dlvtable *) (loader ? ((SList *) loader)->userdata : NULL);
144 }
145
146
147 /* Return the contents of the first item in the global loader list
148 with a matching NAME after removing it from that list. If there
149 was no match, return NULL; if there is an error, return NULL and
150 set an error for lt_dlerror; do not set an error if only resident
151 modules need this loader; in either case, the loader list is not
152 changed if NULL is returned. */
153 lt_dlvtable *
154 lt_dlloader_remove (const char *name)
155 {
156 const lt_dlvtable * vtable = lt_dlloader_find (name);
157 static const char id_string[] = "lt_dlloader_remove";
158 lt_dlinterface_id iface;
159 lt_dlhandle handle = 0;
160 int in_use = 0;
161 int in_use_by_resident = 0;
162
163 if (!vtable)
164 {
165 LT__SETERROR (INVALID_LOADER);
166 return 0;
167 }
168
169 /* Fail if there are any open modules that use this loader. */
170 iface = lt_dlinterface_register (id_string, NULL);
171 while ((handle = lt_dlhandle_iterate (iface, handle)))
172 {
173 lt_dlhandle cur = handle;
174 if (cur->vtable == vtable)
175 {
176 in_use = 1;
177 if (lt_dlisresident (handle))
178 in_use_by_resident = 1;
179 }
180 }
181 lt_dlinterface_free (iface);
182 if (in_use)
183 {
184 if (!in_use_by_resident)
185 LT__SETERROR (REMOVE_LOADER);
186 return 0;
187 }
188
189 /* Call the loader finalisation function. */
190 if (vtable && vtable->dlloader_exit)
191 {
192 if ((*vtable->dlloader_exit) (vtable->dlloader_data) != 0)
193 {
194 /* If there is an exit function, and it returns non-zero
195 then it must set an error, and we will not remove it
196 from the list. */
197 return 0;
198 }
199 }
200
201 /* If we got this far, remove the loader from our global list. */
202 return (lt_dlvtable *)
203 slist_unbox ((SList *) slist_remove (&loaders, loader_callback, (void *) name));
204 }
205
206
207 const lt_dlvtable *
208 lt_dlloader_find (const char *name)
209 {
210 return lt_dlloader_get (slist_find (loaders, loader_callback, (void *) name));
211 }

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