summaryrefslogtreecommitdiff
path: root/gmodule/gmodule-dl.c
blob: 035b2a9e742f3dc811aeeedfa40902423203b207 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
/* GMODULE - GLIB wrapper code for dynamic module loading
 * Copyright (C) 1998, 2000 Tim Janik
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/*
 * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
 * file for a list of people on the GLib Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GLib at ftp://ftp.gtk.org/pub/gtk/. 
 */

/* 
 * MT safe
 */
#include "config.h"

#include <dlfcn.h>

/* Perl includes <nlist.h> and <link.h> instead of <dlfcn.h> on some systmes? */


/* dlerror() is not implemented on all systems
 */
#ifndef	G_MODULE_HAVE_DLERROR
#  ifdef __NetBSD__
#    define dlerror()	g_strerror (errno)
#  else /* !__NetBSD__ */
/* could we rely on errno's state here? */
#    define dlerror()	"unknown dl-error"
#  endif /* !__NetBSD__ */
#endif	/* G_MODULE_HAVE_DLERROR */

/* some flags are missing on some systems, so we provide
 * harmless defaults.
 * The Perl sources say, RTLD_LAZY needs to be defined as (1),
 * at least for Solaris 1.
 *
 * Mandatory:
 * RTLD_LAZY   - resolve undefined symbols as code from the dynamic library
 *		 is executed.
 * RTLD_NOW    - resolve all undefined symbols before dlopen returns, and fail
 *		 if this cannot be done.
 * Optionally:
 * RTLD_GLOBAL - the external symbols defined in the library will be made
 *		 available to subsequently loaded libraries.
 */
#ifndef	RTLD_LAZY
#define	RTLD_LAZY	1
#endif	/* RTLD_LAZY */
#ifndef	RTLD_NOW
#define	RTLD_NOW	0
#endif	/* RTLD_NOW */
/* some systems (OSF1 V5.0) have broken RTLD_GLOBAL linkage */
#ifdef G_MODULE_BROKEN_RTLD_GLOBAL
#undef	RTLD_GLOBAL
#endif /* G_MODULE_BROKEN_RTLD_GLOBAL */
#ifndef	RTLD_GLOBAL
#define	RTLD_GLOBAL	0
#endif	/* RTLD_GLOBAL */


/* --- functions --- */
static gchar*
fetch_dlerror (gboolean replace_null)
{
  gchar *msg = dlerror ();

  /* make sure we always return an error message != NULL, if
   * expected to do so. */

  if (!msg && replace_null)
    return "unknown dl-error";

  return msg;
}

static gpointer
_g_module_open (const gchar *file_name,
		gboolean     bind_lazy,
		gboolean     bind_local)
{
  gpointer handle;
  
  handle = dlopen (file_name,
		   (bind_local ? 0 : RTLD_GLOBAL) | (bind_lazy ? RTLD_LAZY : RTLD_NOW));
  if (!handle)
    g_module_set_error (fetch_dlerror (TRUE));
  
  return handle;
}

static gpointer
_g_module_self (void)
{
  gpointer handle;
  
  /* to query symbols from the program itself, special link options
   * are required on some systems.
   */
  
  handle = dlopen (NULL, RTLD_GLOBAL | RTLD_LAZY);
  if (!handle)
    g_module_set_error (fetch_dlerror (TRUE));
  
  return handle;
}

static void
_g_module_close (gpointer handle,
		 gboolean is_unref)
{
  /* are there any systems out there that have dlopen()/dlclose()
   * without a reference count implementation?
   */
  is_unref |= 1;
  
  if (is_unref)
    {
      if (dlclose (handle) != 0)
	g_module_set_error (fetch_dlerror (TRUE));
    }
}

static gpointer
_g_module_symbol (gpointer     handle,
		  const gchar *symbol_name)
{
  gpointer p;
  gchar *msg;

  fetch_dlerror (FALSE);
  p = dlsym (handle, symbol_name);
  msg = fetch_dlerror (FALSE);
  if (msg)
    g_module_set_error (msg);
  
  return p;
}

static gchar*
_g_module_build_path (const gchar *directory,
		      const gchar *module_name)
{
  if (directory && *directory) {
    if (strncmp (module_name, "lib", 3) == 0)
      return g_strconcat (directory, "/", module_name, NULL);
    else
      return g_strconcat (directory, "/lib", module_name, "." G_MODULE_SUFFIX, NULL);
  } else if (strncmp (module_name, "lib", 3) == 0)
    return g_strdup (module_name);
  else
    return g_strconcat ("lib", module_name, "." G_MODULE_SUFFIX, NULL);
}