1 /* loader-dlopen.c -- dynamic linking with dlopen/dlsym
3 Copyright (C) 1998, 1999, 2000, 2004, 2006,
4 2007, 2008 Free Software Foundation, Inc.
5 Written by Thomas Tanner, 1998
7 NOTE: The canonical source of this file is maintained with the
8 GNU Libtool package. Report bugs to bug-libtool@gnu.org.
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.
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.
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.
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.
32 #include "lt__private.h"
33 #include "lt_dlloader.h"
35 /* Use the preprocessor to rename non-static symbols to avoid namespace
36 collisions when the loader code is statically linked into libltdl.
37 Use the "<module_name>_LTX_" prefix so that the symbol addresses can
38 be fetched from the preloaded symbol list by lt_dlsym(): */
39 #define get_vtable dlopen_LTX_get_vtable
42 LT_SCOPE lt_dlvtable
*get_vtable (lt_user_data loader_data
);
46 /* Boilerplate code to set up the vtable for hooking this loader into
47 libltdl's loader list: */
48 static int vl_exit (lt_user_data loader_data
);
49 static lt_module
vm_open (lt_user_data loader_data
, const char *filename
,
51 static int vm_close (lt_user_data loader_data
, lt_module module
);
52 static void * vm_sym (lt_user_data loader_data
, lt_module module
,
53 const char *symbolname
);
55 static lt_dlvtable
*vtable
= 0;
57 /* Return the vtable for this loader, only the name and sym_prefix
58 attributes (plus the virtual function implementations, obviously)
59 change between loaders. */
61 get_vtable (lt_user_data loader_data
)
65 vtable
= (lt_dlvtable
*) lt__zalloc (sizeof *vtable
);
68 if (vtable
&& !vtable
->name
)
70 vtable
->name
= "lt_dlopen";
71 #if defined(DLSYM_USCORE)
72 vtable
->sym_prefix
= "_";
74 vtable
->module_open
= vm_open
;
75 vtable
->module_close
= vm_close
;
76 vtable
->find_sym
= vm_sym
;
77 vtable
->dlloader_exit
= vl_exit
;
78 vtable
->dlloader_data
= loader_data
;
79 vtable
->priority
= LT_DLLOADER_PREPEND
;
82 if (vtable
&& (vtable
->dlloader_data
!= loader_data
))
84 LT__SETERROR (INIT_LOADER
);
93 /* --- IMPLEMENTATION --- */
96 #if defined(HAVE_DLFCN_H)
100 #if defined(HAVE_SYS_DL_H)
105 /* We may have to define LT_LAZY_OR_NOW in the command line if we
106 find out it does not work in some platform. */
107 #if !defined(LT_LAZY_OR_NOW)
108 # if defined(RTLD_LAZY)
109 # define LT_LAZY_OR_NOW RTLD_LAZY
111 # if defined(DL_LAZY)
112 # define LT_LAZY_OR_NOW DL_LAZY
114 # endif /* !RTLD_LAZY */
116 #if !defined(LT_LAZY_OR_NOW)
117 # if defined(RTLD_NOW)
118 # define LT_LAZY_OR_NOW RTLD_NOW
121 # define LT_LAZY_OR_NOW DL_NOW
123 # endif /* !RTLD_NOW */
125 #if !defined(LT_LAZY_OR_NOW)
126 # define LT_LAZY_OR_NOW 0
127 #endif /* !LT_LAZY_OR_NOW */
129 /* We only support local and global symbols from modules for loaders
130 that provide such a thing, otherwise the system default is used. */
131 #if !defined(RTLD_GLOBAL)
132 # if defined(DL_GLOBAL)
133 # define RTLD_GLOBAL DL_GLOBAL
135 #endif /* !RTLD_GLOBAL */
136 #if !defined(RTLD_LOCAL)
137 # if defined(DL_LOCAL)
138 # define RTLD_LOCAL DL_LOCAL
140 #endif /* !RTLD_LOCAL */
142 #if defined(HAVE_DLERROR)
143 # define DLERROR(arg) dlerror ()
145 # define DLERROR(arg) LT__STRERROR (arg)
148 #define DL__SETERROR(errorcode) \
149 LT__SETERRORSTR (DLERROR (errorcode))
152 /* A function called through the vtable when this loader is no
153 longer needed by the application. */
155 vl_exit (lt_user_data LT__UNUSED loader_data
)
162 /* A function called through the vtable to open a module with this
163 loader. Returns an opaque representation of the newly opened
164 module for processing with this loader's other vtable functions. */
166 vm_open (lt_user_data LT__UNUSED loader_data
, const char *filename
,
169 int module_flags
= LT_LAZY_OR_NOW
;
175 /* If there is some means of asking for global symbol resolution,
177 if (advise
->is_symglobal
)
178 module_flags
|= RTLD_GLOBAL
;
180 /* Otherwise, reset that bit so the caller can tell it wasn't
182 advise
->is_symglobal
= 0;
185 /* And similarly for local only symbol resolution. */
187 if (advise
->is_symlocal
)
188 module_flags
|= RTLD_LOCAL
;
190 advise
->is_symlocal
= 0;
194 module
= dlopen (filename
, module_flags
);
198 DL__SETERROR (CANNOT_OPEN
);
205 /* A function called through the vtable when a particular module
206 should be unloaded. */
208 vm_close (lt_user_data LT__UNUSED loader_data
, lt_module module
)
212 if (dlclose (module
) != 0)
214 DL__SETERROR (CANNOT_CLOSE
);
222 /* A function called through the vtable to get the address of
223 a symbol loaded from a particular module. */
225 vm_sym (lt_user_data LT__UNUSED loader_data
, lt_module module
, const char *name
)
227 void *address
= dlsym (module
, name
);
231 DL__SETERROR (SYMBOL_NOT_FOUND
);