/[svn]/ircd-hybrid-7.2/libltdl/lt_dlloader.c
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Contents of /ircd-hybrid-7.2/libltdl/lt_dlloader.c

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Revision 945 - (show annotations)
Mon Jul 20 15:48:27 2009 UTC (10 years, 1 month ago) by michael
File MIME type: text/x-chdr
File size: 6046 byte(s)
- fixed some configure mess and imported latest libtool sources

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
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_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, 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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