1 /* loader-dyld.c -- dynamic linking on darwin and OS X
3 Copyright (C) 1998, 1999, 2000, 2004, 2006,
4 2007, 2008 Free Software Foundation, Inc.
5 Written by Peter O'Gorman, 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 dyld_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_init (lt_user_data loader_data
);
49 static int vl_exit (lt_user_data loader_data
);
50 static lt_module
vm_open (lt_user_data loader_data
, const char *filename
,
52 static int vm_close (lt_user_data loader_data
, lt_module module
);
53 static void * vm_sym (lt_user_data loader_data
, lt_module module
,
54 const char *symbolname
);
56 static lt_dlvtable
*vtable
= 0;
58 /* Return the vtable for this loader, only the name and sym_prefix
59 attributes (plus the virtual function implementations, obviously)
60 change between loaders. */
62 get_vtable (lt_user_data loader_data
)
66 vtable
= lt__zalloc (sizeof *vtable
);
69 if (vtable
&& !vtable
->name
)
71 vtable
->name
= "lt_dyld";
72 vtable
->sym_prefix
= "_";
73 vtable
->dlloader_init
= vl_init
;
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_APPEND
;
82 if (vtable
&& (vtable
->dlloader_data
!= loader_data
))
84 LT__SETERROR (INIT_LOADER
);
93 /* --- IMPLEMENTATION --- */
96 #if defined(HAVE_MACH_O_DYLD_H)
97 # if !defined(__APPLE_CC__) && !defined(__MWERKS__) && !defined(__private_extern__)
98 /* Is this correct? Does it still function properly? */
99 # define __private_extern__ extern
101 # include <mach-o/dyld.h>
104 #include <mach-o/getsect.h>
106 /* We have to put some stuff here that isn't in older dyld.h files */
107 #if !defined(ENUM_DYLD_BOOL)
108 # define ENUM_DYLD_BOOL
116 #if !defined(LC_REQ_DYLD)
117 # define LC_REQ_DYLD 0x80000000
119 #if !defined(LC_LOAD_WEAK_DYLIB)
120 # define LC_LOAD_WEAK_DYLIB (0x18 | LC_REQ_DYLD)
123 #if !defined(NSADDIMAGE_OPTION_NONE)
124 # define NSADDIMAGE_OPTION_NONE 0x0
126 #if !defined(NSADDIMAGE_OPTION_RETURN_ON_ERROR)
127 # define NSADDIMAGE_OPTION_RETURN_ON_ERROR 0x1
129 #if !defined(NSADDIMAGE_OPTION_WITH_SEARCHING)
130 # define NSADDIMAGE_OPTION_WITH_SEARCHING 0x2
132 #if !defined(NSADDIMAGE_OPTION_RETURN_ONLY_IF_LOADED)
133 # define NSADDIMAGE_OPTION_RETURN_ONLY_IF_LOADED 0x4
135 #if !defined(NSADDIMAGE_OPTION_MATCH_FILENAME_BY_INSTALLNAME)
136 # define NSADDIMAGE_OPTION_MATCH_FILENAME_BY_INSTALLNAME 0x8
139 #if !defined(NSLOOKUPSYMBOLINIMAGE_OPTION_BIND)
140 # define NSLOOKUPSYMBOLINIMAGE_OPTION_BIND 0x0
142 #if !defined(NSLOOKUPSYMBOLINIMAGE_OPTION_BIND_NOW)
143 # define NSLOOKUPSYMBOLINIMAGE_OPTION_BIND_NOW 0x1
145 #if !defined(NSLOOKUPSYMBOLINIMAGE_OPTION_BIND_FULLY)
146 # define NSLOOKUPSYMBOLINIMAGE_OPTION_BIND_FULLY 0x2
148 #if !defined(NSLOOKUPSYMBOLINIMAGE_OPTION_RETURN_ON_ERROR)
149 # define NSLOOKUPSYMBOLINIMAGE_OPTION_RETURN_ON_ERROR 0x4
152 #define LT__SYMLOOKUP_OPTS (NSLOOKUPSYMBOLINIMAGE_OPTION_BIND_NOW \
153 | NSLOOKUPSYMBOLINIMAGE_OPTION_RETURN_ON_ERROR)
155 #if defined(__BIG_ENDIAN__)
156 # define LT__MAGIC MH_MAGIC
158 # define LT__MAGIC MH_CIGAM
161 #define DYLD__SETMYERROR(errmsg) LT__SETERRORSTR (dylderror (errmsg))
162 #define DYLD__SETERROR(errcode) DYLD__SETMYERROR (LT__STRERROR (errcode))
164 typedef struct mach_header mach_header
;
165 typedef struct dylib_command dylib_command
;
167 static const char *dylderror (const char *errmsg
);
168 static const mach_header
*lt__nsmodule_get_header (NSModule module
);
169 static const char *lt__header_get_instnam (const mach_header
*mh
);
170 static const mach_header
*lt__match_loadedlib (const char *name
);
171 static NSSymbol
lt__linkedlib_symbol (const char *symname
, const mach_header
*mh
);
173 static const mach_header
*(*lt__addimage
) (const char *image_name
,
174 unsigned long options
) = 0;
175 static NSSymbol (*lt__image_symbol
) (const mach_header
*image
,
176 const char *symbolName
,
177 unsigned long options
) = 0;
178 static enum DYLD_BOOL (*lt__image_symbol_p
) (const mach_header
*image
,
179 const char *symbolName
) = 0;
180 static enum DYLD_BOOL (*lt__module_export
) (NSModule module
) = 0;
182 static int dyld_cannot_close
= 0;
185 /* A function called through the vtable when this loader is no
186 longer needed by the application. */
188 vl_exit (lt_user_data LT__UNUSED loader_data
)
194 /* A function called through the vtable to initialise this loader. */
196 vl_init (lt_user_data loader_data
)
200 if (! dyld_cannot_close
)
202 if (!_dyld_present ())
208 (void) _dyld_func_lookup ("__dyld_NSAddImage",
209 (unsigned long*) <__addimage
);
210 (void) _dyld_func_lookup ("__dyld_NSLookupSymbolInImage",
211 (unsigned long*)<__image_symbol
);
212 (void) _dyld_func_lookup ("__dyld_NSIsSymbolNameDefinedInImage",
213 (unsigned long*) <__image_symbol_p
);
214 (void) _dyld_func_lookup ("__dyld_NSMakePrivateModulePublic",
215 (unsigned long*) <__module_export
);
216 dyld_cannot_close
= lt_dladderror ("can't close a dylib");
224 /* A function called through the vtable to open a module with this
225 loader. Returns an opaque representation of the newly opened
226 module for processing with this loader's other vtable functions. */
228 vm_open (lt_user_data loader_data
, const char *filename
,
229 lt_dladvise LT__UNUSED advise
)
231 lt_module module
= 0;
232 NSObjectFileImage ofi
= 0;
236 return (lt_module
) -1;
239 switch (NSCreateObjectFileImageFromFile (filename
, &ofi
))
241 case NSObjectFileImageSuccess
:
242 module
= NSLinkModule (ofi
, filename
, NSLINKMODULE_OPTION_RETURN_ON_ERROR
243 | NSLINKMODULE_OPTION_PRIVATE
244 | NSLINKMODULE_OPTION_BINDNOW
);
245 NSDestroyObjectFileImage (ofi
);
249 lt__module_export (module
);
253 case NSObjectFileImageInappropriateFile
:
254 if (lt__image_symbol_p
&& lt__image_symbol
)
256 module
= (lt_module
) lt__addimage(filename
,
257 NSADDIMAGE_OPTION_RETURN_ON_ERROR
);
261 case NSObjectFileImageFailure
:
262 case NSObjectFileImageArch
:
263 case NSObjectFileImageFormat
:
264 case NSObjectFileImageAccess
:
271 DYLD__SETERROR (CANNOT_OPEN
);
278 /* A function called through the vtable when a particular module
279 should be unloaded. */
281 vm_close (lt_user_data loader_data
, lt_module module
)
285 if (module
!= (lt_module
) -1)
287 const mach_header
*mh
= (const mach_header
*) module
;
289 if (mh
->magic
== LT__MAGIC
)
291 lt_dlseterror (dyld_cannot_close
);
296 /* Currently, if a module contains c++ static destructors and it
297 is unloaded, we get a segfault in atexit(), due to compiler and
298 dynamic loader differences of opinion, this works around that. */
299 if ((const struct section
*) NULL
!=
300 getsectbynamefromheader (lt__nsmodule_get_header (module
),
301 "__DATA", "__mod_term_func"))
303 flags
|= NSUNLINKMODULE_OPTION_KEEP_MEMORY_MAPPED
;
306 flags
|= NSUNLINKMODULE_OPTION_RESET_LAZY_REFERENCES
;
308 if (!NSUnLinkModule (module
, flags
))
310 DYLD__SETERROR (CANNOT_CLOSE
);
319 /* A function called through the vtable to get the address of
320 a symbol loaded from a particular module. */
322 vm_sym (lt_user_data loader_data
, lt_module module
, const char *name
)
325 const mach_header
*mh
= (const mach_header
*) module
;
326 char saveError
[256] = "Symbol not found";
328 if (module
== (lt_module
) -1)
330 void *address
, *unused
;
331 _dyld_lookup_and_bind (name
, (unsigned long*) &address
, &unused
);
335 if (mh
->magic
== LT__MAGIC
)
337 if (lt__image_symbol_p
&& lt__image_symbol
)
339 if (lt__image_symbol_p (mh
, name
))
341 nssym
= lt__image_symbol (mh
, name
, LT__SYMLOOKUP_OPTS
);
348 nssym
= NSLookupSymbolInModule (module
, name
);
353 strncpy (saveError
, dylderror (LT__STRERROR (SYMBOL_NOT_FOUND
)), 255);
357 mh
= (mach_header
*)lt__nsmodule_get_header (module
);
359 nssym
= lt__linkedlib_symbol (name
, mh
);
364 LT__SETERRORSTR (saveError
);
367 return nssym
? NSAddressOfSymbol (nssym
) : 0;
373 /* --- HELPER FUNCTIONS --- */
376 /* Return the dyld error string, or the passed in error string if none. */
378 dylderror (const char *errmsg
)
380 NSLinkEditErrors ler
;
385 NSLinkEditError (&ler
, &lerno
, &file
, &errstr
);
387 if (! (errstr
&& *errstr
))
395 /* There should probably be an apple dyld api for this. */
396 static const mach_header
*
397 lt__nsmodule_get_header (NSModule module
)
399 int i
= _dyld_image_count();
400 const char *modname
= NSNameOfModule (module
);
401 const mach_header
*mh
= 0;
409 if (strneq (_dyld_get_image_name (i
), modname
))
411 mh
= _dyld_get_image_header (i
);
419 /* NSAddImage is also used to get the loaded image, but it only works if
420 the lib is installed, for uninstalled libs we need to check the
421 install_names against each other. Note that this is still broken if
422 DYLD_IMAGE_SUFFIX is set and a different lib was loaded as a result. */
424 lt__header_get_instnam (const mach_header
*mh
)
426 unsigned long offset
= sizeof(mach_header
);
427 const char* result
= 0;
430 for (j
= 0; j
< mh
->ncmds
; j
++)
432 struct load_command
*lc
;
434 lc
= (struct load_command
*) (((unsigned long) mh
) + offset
);
435 if (LC_ID_DYLIB
== lc
->cmd
)
437 result
=(char*)(((dylib_command
*) lc
)->dylib
.name
.offset
+
440 offset
+= lc
->cmdsize
;
446 static const mach_header
*
447 lt__match_loadedlib (const char *name
)
449 const mach_header
*mh
= 0;
450 int i
= _dyld_image_count();
457 id
= lt__header_get_instnam (_dyld_get_image_header (i
));
458 if (id
&& strneq (id
, name
))
460 mh
= _dyld_get_image_header (i
);
468 /* Safe to assume our mh is good. */
470 lt__linkedlib_symbol (const char *symname
, const mach_header
*mh
)
474 if (lt__image_symbol
&& NSIsSymbolNameDefined (symname
))
476 unsigned long offset
= sizeof(mach_header
);
477 struct load_command
*lc
;
480 for (j
= 0; j
< mh
->ncmds
; j
++)
482 lc
= (struct load_command
*) (((unsigned long) mh
) + offset
);
483 if ((LC_LOAD_DYLIB
== lc
->cmd
) || (LC_LOAD_WEAK_DYLIB
== lc
->cmd
))
485 unsigned long base
= ((dylib_command
*) lc
)->dylib
.name
.offset
;
486 char *name
= (char *) (base
+ (unsigned long) lc
);
487 const mach_header
*mh1
= lt__match_loadedlib (name
);
491 /* Maybe NSAddImage can find it */
492 mh1
= lt__addimage (name
,
493 NSADDIMAGE_OPTION_RETURN_ONLY_IF_LOADED
494 | NSADDIMAGE_OPTION_WITH_SEARCHING
495 | NSADDIMAGE_OPTION_RETURN_ON_ERROR
);
500 symbol
= lt__image_symbol (mh1
, symname
, LT__SYMLOOKUP_OPTS
);
506 offset
+= lc
->cmdsize
;