1 /* GMODULE - GLIB wrapper code for dynamic module loading
2 * Copyright (C) 1998, 2000 Tim Janik
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
18 */
19
20 /*
21 * Modified by the GLib Team and others 1997-2000. See the AUTHORS
22 * file for a list of people on the GLib Team. See the ChangeLog
23 * files for a list of changes. These files are distributed with
24 * GLib at ftp://ftp.gtk.org/pub/gtk/.
25 */
26
27 /*
28 * MT safe
29 */
30 #include "config.h"
31
32 #include <dlfcn.h>
33
34 /* Perl includes <nlist.h> and <link.h> instead of <dlfcn.h> on some systmes? */
35
36
37 /* dlerror() is not implemented on all systems
38 */
39 #ifndef G_MODULE_HAVE_DLERROR
40 # ifdef __NetBSD__
41 # define dlerror() g_strerror (errno)
42 # else /* !__NetBSD__ */
43 /* could we rely on errno's state here? */
44 # define dlerror() "unknown dl-error"
45 # endif /* !__NetBSD__ */
46 #endif /* G_MODULE_HAVE_DLERROR */
47
48 /* some flags are missing on some systems, so we provide
49 * harmless defaults.
50 * The Perl sources say, RTLD_LAZY needs to be defined as (1),
51 * at least for Solaris 1.
52 *
53 * Mandatory:
54 * RTLD_LAZY - resolve undefined symbols as code from the dynamic library
55 * is executed.
56 * RTLD_NOW - resolve all undefined symbols before dlopen returns, and fail
57 * if this cannot be done.
58 * Optionally:
59 * RTLD_GLOBAL - the external symbols defined in the library will be made
60 * available to subsequently loaded libraries.
61 */
62 #ifndef RTLD_LAZY
63 #define RTLD_LAZY 1
64 #endif /* RTLD_LAZY */
65 #ifndef RTLD_NOW
66 #define RTLD_NOW 0
67 #endif /* RTLD_NOW */
68 /* some systems (OSF1 V5.0) have broken RTLD_GLOBAL linkage */
69 #ifdef G_MODULE_BROKEN_RTLD_GLOBAL
70 #undef RTLD_GLOBAL
71 #endif /* G_MODULE_BROKEN_RTLD_GLOBAL */
72 #ifndef RTLD_GLOBAL
73 #define RTLD_GLOBAL 0
74 #endif /* RTLD_GLOBAL */
75
76
77 /* --- functions --- */
78 static gchar*
fetch_dlerror(gboolean replace_null)79 fetch_dlerror (gboolean replace_null)
80 {
81 gchar *msg = dlerror ();
82
83 /* make sure we always return an error message != NULL, if
84 * expected to do so. */
85
86 if (!msg && replace_null)
87 return "unknown dl-error";
88
89 return msg;
90 }
91
92 static gpointer
_g_module_open(const gchar * file_name,gboolean bind_lazy,gboolean bind_local)93 _g_module_open (const gchar *file_name,
94 gboolean bind_lazy,
95 gboolean bind_local)
96 {
97 gpointer handle;
98
99 handle = dlopen (file_name,
100 (bind_local ? 0 : RTLD_GLOBAL) | (bind_lazy ? RTLD_LAZY : RTLD_NOW));
101 if (!handle)
102 g_module_set_error (fetch_dlerror (TRUE));
103
104 return handle;
105 }
106
107 static gpointer
_g_module_self(void)108 _g_module_self (void)
109 {
110 gpointer handle;
111
112 /* to query symbols from the program itself, special link options
113 * are required on some systems.
114 */
115
116 handle = dlopen (NULL, RTLD_GLOBAL | RTLD_LAZY);
117 if (!handle)
118 g_module_set_error (fetch_dlerror (TRUE));
119
120 return handle;
121 }
122
123 static void
_g_module_close(gpointer handle,gboolean is_unref)124 _g_module_close (gpointer handle,
125 gboolean is_unref)
126 {
127 /* are there any systems out there that have dlopen()/dlclose()
128 * without a reference count implementation?
129 */
130 is_unref |= 1;
131
132 if (is_unref)
133 {
134 if (dlclose (handle) != 0)
135 g_module_set_error (fetch_dlerror (TRUE));
136 }
137 }
138
139 static gpointer
_g_module_symbol(gpointer handle,const gchar * symbol_name)140 _g_module_symbol (gpointer handle,
141 const gchar *symbol_name)
142 {
143 gpointer p;
144 gchar *msg;
145
146 fetch_dlerror (FALSE);
147 p = dlsym (handle, symbol_name);
148 msg = fetch_dlerror (FALSE);
149 if (msg)
150 g_module_set_error (msg);
151
152 return p;
153 }
154
155 static gchar*
_g_module_build_path(const gchar * directory,const gchar * module_name)156 _g_module_build_path (const gchar *directory,
157 const gchar *module_name)
158 {
159 if (directory && *directory) {
160 if (strncmp (module_name, "lib", 3) == 0)
161 return g_strconcat (directory, "/", module_name, NULL);
162 else
163 return g_strconcat (directory, "/lib", module_name, "." G_MODULE_SUFFIX, NULL);
164 } else if (strncmp (module_name, "lib", 3) == 0)
165 return g_strdup (module_name);
166 else
167 return g_strconcat ("lib", module_name, "." G_MODULE_SUFFIX, NULL);
168 }
169