/[svn]/ircd-hybrid-7.2/libltdl/loaders/dlopen.c
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Annotation of /ircd-hybrid-7.2/libltdl/loaders/dlopen.c

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Revision 945 - (hide annotations)
Mon Jul 20 15:48:27 2009 UTC (10 years, 11 months ago) by michael
File MIME type: text/x-chdr
File size: 6369 byte(s)
- fixed some configure mess and imported latest libtool sources

1 michael 945 /* 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     }

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