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8d138742 CE |
1 | /* loader-dlopen.c -- dynamic linking with dlopen/dlsym |
2 | ||
3 | Copyright (C) 1998, 1999, 2000, 2004, 2006, | |
4 | 2007, 2008 Free Software Foundation, Inc. | |
5 | Written by Thomas Tanner, 1998 | |
6 | ||
7 | NOTE: The canonical source of this file is maintained with the | |
8 | GNU Libtool package. Report bugs to bug-libtool@gnu.org. | |
9 | ||
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. | |
14 | ||
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. | |
19 | ||
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. | |
24 | ||
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. | |
30 | */ | |
31 | ||
32 | #include "lt__private.h" | |
33 | #include "lt_dlloader.h" | |
34 | ||
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 | |
40 | ||
41 | LT_BEGIN_C_DECLS | |
42 | LT_SCOPE lt_dlvtable *get_vtable (lt_user_data loader_data); | |
43 | LT_END_C_DECLS | |
44 | ||
45 | ||
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, | |
50 | lt_dladvise advise); | |
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); | |
54 | ||
55 | static lt_dlvtable *vtable = 0; | |
56 | ||
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. */ | |
60 | lt_dlvtable * | |
61 | get_vtable (lt_user_data loader_data) | |
62 | { | |
63 | if (!vtable) | |
64 | { | |
65 | vtable = (lt_dlvtable *) lt__zalloc (sizeof *vtable); | |
66 | } | |
67 | ||
68 | if (vtable && !vtable->name) | |
69 | { | |
70 | vtable->name = "lt_dlopen"; | |
71 | #if defined(DLSYM_USCORE) | |
72 | vtable->sym_prefix = "_"; | |
73 | #endif | |
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; | |
80 | } | |
81 | ||
82 | if (vtable && (vtable->dlloader_data != loader_data)) | |
83 | { | |
84 | LT__SETERROR (INIT_LOADER); | |
85 | return 0; | |
86 | } | |
87 | ||
88 | return vtable; | |
89 | } | |
90 | ||
91 | ||
92 | ||
93 | /* --- IMPLEMENTATION --- */ | |
94 | ||
95 | ||
96 | #if defined(HAVE_DLFCN_H) | |
97 | # include <dlfcn.h> | |
98 | #endif | |
99 | ||
100 | #if defined(HAVE_SYS_DL_H) | |
101 | # include <sys/dl.h> | |
102 | #endif | |
103 | ||
104 | ||
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 | |
110 | # else | |
111 | # if defined(DL_LAZY) | |
112 | # define LT_LAZY_OR_NOW DL_LAZY | |
113 | # endif | |
114 | # endif /* !RTLD_LAZY */ | |
115 | #endif | |
116 | #if !defined(LT_LAZY_OR_NOW) | |
117 | # if defined(RTLD_NOW) | |
118 | # define LT_LAZY_OR_NOW RTLD_NOW | |
119 | # else | |
120 | # if defined(DL_NOW) | |
121 | # define LT_LAZY_OR_NOW DL_NOW | |
122 | # endif | |
123 | # endif /* !RTLD_NOW */ | |
124 | #endif | |
125 | #if !defined(LT_LAZY_OR_NOW) | |
126 | # define LT_LAZY_OR_NOW 0 | |
127 | #endif /* !LT_LAZY_OR_NOW */ | |
128 | ||
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 | |
134 | # endif | |
135 | #endif /* !RTLD_GLOBAL */ | |
136 | #if !defined(RTLD_LOCAL) | |
137 | # if defined(DL_LOCAL) | |
138 | # define RTLD_LOCAL DL_LOCAL | |
139 | # endif | |
140 | #endif /* !RTLD_LOCAL */ | |
141 | ||
142 | #if defined(HAVE_DLERROR) | |
143 | # define DLERROR(arg) dlerror () | |
144 | #else | |
145 | # define DLERROR(arg) LT__STRERROR (arg) | |
146 | #endif | |
147 | ||
148 | #define DL__SETERROR(errorcode) \ | |
149 | LT__SETERRORSTR (DLERROR (errorcode)) | |
150 | ||
151 | ||
152 | /* A function called through the vtable when this loader is no | |
153 | longer needed by the application. */ | |
154 | static int | |
155 | vl_exit (lt_user_data LT__UNUSED loader_data) | |
156 | { | |
157 | vtable = NULL; | |
158 | return 0; | |
159 | } | |
160 | ||
161 | ||
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. */ | |
165 | static lt_module | |
166 | vm_open (lt_user_data LT__UNUSED loader_data, const char *filename, | |
167 | lt_dladvise advise) | |
168 | { | |
169 | int module_flags = LT_LAZY_OR_NOW; | |
170 | lt_module module; | |
171 | ||
172 | if (advise) | |
173 | { | |
174 | #ifdef RTLD_GLOBAL | |
175 | /* If there is some means of asking for global symbol resolution, | |
176 | do so. */ | |
177 | if (advise->is_symglobal) | |
178 | module_flags |= RTLD_GLOBAL; | |
179 | #else | |
180 | /* Otherwise, reset that bit so the caller can tell it wasn't | |
181 | acted on. */ | |
182 | advise->is_symglobal = 0; | |
183 | #endif | |
184 | ||
185 | /* And similarly for local only symbol resolution. */ | |
186 | #ifdef RTLD_LOCAL | |
187 | if (advise->is_symlocal) | |
188 | module_flags |= RTLD_LOCAL; | |
189 | #else | |
190 | advise->is_symlocal = 0; | |
191 | #endif | |
192 | } | |
193 | ||
194 | module = dlopen (filename, module_flags); | |
195 | ||
196 | if (!module) | |
197 | { | |
198 | DL__SETERROR (CANNOT_OPEN); | |
199 | } | |
200 | ||
201 | return module; | |
202 | } | |
203 | ||
204 | ||
205 | /* A function called through the vtable when a particular module | |
206 | should be unloaded. */ | |
207 | static int | |
208 | vm_close (lt_user_data LT__UNUSED loader_data, lt_module module) | |
209 | { | |
210 | int errors = 0; | |
211 | ||
212 | if (dlclose (module) != 0) | |
213 | { | |
214 | DL__SETERROR (CANNOT_CLOSE); | |
215 | ++errors; | |
216 | } | |
217 | ||
218 | return errors; | |
219 | } | |
220 | ||
221 | ||
222 | /* A function called through the vtable to get the address of | |
223 | a symbol loaded from a particular module. */ | |
224 | static void * | |
225 | vm_sym (lt_user_data LT__UNUSED loader_data, lt_module module, const char *name) | |
226 | { | |
227 | void *address = dlsym (module, name); | |
228 | ||
229 | if (!address) | |
230 | { | |
231 | DL__SETERROR (SYMBOL_NOT_FOUND); | |
232 | } | |
233 | ||
234 | return address; | |
235 | } |