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 <dl.h>
33
34
35 /* some flags are missing on some systems, so we provide
36 * harmless defaults.
37 *
38 * Mandatory:
39 * BIND_IMMEDIATE - Resolve symbol references when the library is loaded.
40 * BIND_DEFERRED - Delay code symbol resolution until actual reference.
41 *
42 * Optionally:
43 * BIND_FIRST - Place the library at the head of the symbol search order.
44 * BIND_NONFATAL - The default BIND_IMMEDIATE behavior is to treat all unsatisfied
45 * symbols as fatal. This flag allows binding of unsatisfied code
46 * symbols to be deferred until use.
47 * [Perl: For certain libraries, like DCE, deferred binding often
48 * causes run time problems. Adding BIND_NONFATAL to BIND_IMMEDIATE
49 * still allows unresolved references in situations like this.]
50 * BIND_NOSTART - Do not call the initializer for the shared library when the
51 * library is loaded, nor on a future call to shl_unload().
52 * BIND_VERBOSE - Print verbose messages concerning possible unsatisfied symbols.
53 *
54 * hp9000s700/hp9000s800:
55 * BIND_RESTRICTED - Restrict symbols visible by the library to those present at
56 * library load time.
57 * DYNAMIC_PATH - Allow the loader to dynamically search for the library specified
58 * by the path argument.
59 */
60 #ifndef DYNAMIC_PATH
61 #define DYNAMIC_PATH 0
62 #endif /* DYNAMIC_PATH */
63 #ifndef BIND_RESTRICTED
64 #define BIND_RESTRICTED 0
65 #endif /* BIND_RESTRICTED */
66
67 #define OPT_BIND_FLAGS (BIND_NONFATAL | BIND_VERBOSE)
68
69
70 /* --- functions --- */
71
72 /*
73 * shl_load() does not appear to support making symbols invisible to
74 * the global namespace. However, the default is to put the library
75 * last in the search order, which is approximately what we want,
76 * since it will cause symbols that conflict with existing symbols to
77 * be invisible. It is unclear if BIND_FIRST should be used when
78 * bind_local==0, since it may cause the loaded symbols to be used
79 * preferentially to the application's symbols, which is Almost
80 * Always Wrong. --ds
81 */
82 static gpointer
_g_module_open(const gchar * file_name,gboolean bind_lazy,gboolean bind_local)83 _g_module_open (const gchar *file_name,
84 gboolean bind_lazy,
85 gboolean bind_local)
86 {
87 shl_t shl_handle;
88
89 shl_handle = shl_load (file_name,
90 (bind_lazy ? BIND_DEFERRED : BIND_IMMEDIATE) | OPT_BIND_FLAGS, 0);
91 if (!shl_handle)
92 {
93 /* the hp-docs say we should better abort() if errno==ENOSYM ;( */
94 g_module_set_error (g_strerror (errno));
95 }
96
97 return (gpointer) shl_handle;
98 }
99
100 static gpointer
_g_module_self(void)101 _g_module_self (void)
102 {
103 shl_t shl_handle;
104
105 shl_handle = PROG_HANDLE;
106 if (!shl_handle)
107 g_module_set_error (g_strerror (errno));
108
109 return shl_handle;
110 }
111
112 static void
_g_module_close(gpointer handle,gboolean is_unref)113 _g_module_close (gpointer handle,
114 gboolean is_unref)
115 {
116 if (!is_unref)
117 {
118 if (shl_unload ((shl_t) handle) != 0)
119 g_module_set_error (g_strerror (errno));
120 }
121 }
122
123 static gpointer
_g_module_symbol(gpointer handle,const gchar * symbol_name)124 _g_module_symbol (gpointer handle,
125 const gchar *symbol_name)
126 {
127 gpointer p = NULL;
128
129 /* should we restrict lookups to TYPE_PROCEDURE?
130 */
131 if (handle == PROG_HANDLE)
132 {
133 /* PROG_HANDLE will only lookup symbols in the program itself, not honouring
134 * libraries. passing NULL as a handle will also try to lookup the symbol
135 * in currently loaded libraries. fix pointed out and supplied by:
136 * David Gero <dgero@nortelnetworks.com>
137 */
138 handle = NULL;
139 }
140 if (shl_findsym ((shl_t*) &handle, symbol_name, TYPE_UNDEFINED, &p) != 0 ||
141 handle == NULL || p == NULL)
142 {
143 /* the hp-docs say we should better abort() if errno==ENOSYM ;( */
144 g_module_set_error (g_strerror (errno));
145 }
146
147 return p;
148 }
149
150 static gchar*
_g_module_build_path(const gchar * directory,const gchar * module_name)151 _g_module_build_path (const gchar *directory,
152 const gchar *module_name)
153 {
154 if (directory && *directory)
155 if (strncmp (module_name, "lib", 3) == 0)
156 return g_strconcat (directory, "/", module_name, NULL);
157 else
158 return g_strconcat (directory, "/lib", module_name, ".sl", NULL);
159 else if (strncmp (module_name, "lib", 3) == 0)
160 return g_strdup (module_name);
161 else
162 return g_strconcat ("lib", module_name, ".sl", NULL);
163 }
164