1 /* Handle loading and unloading shared objects for internal libc purposes.
2 Copyright (C) 1999, 2000, 2001, 2002, 2004 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Zack Weinberg <zack@rabi.columbia.edu>, 1999.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
25 extern int __libc_argc attribute_hidden
;
26 extern char **__libc_argv attribute_hidden
;
28 extern char **__environ
;
30 /* The purpose of this file is to provide wrappers around the dynamic
31 linker error mechanism (similar to dlopen() et al in libdl) which
32 are usable from within libc. Generally we want to throw away the
33 string that dlerror() would return and just pass back a null pointer
34 for errors. This also lets the rest of libc not know about the error
37 Much of this code came from gconv_dl.c with slight modifications. */
41 dlerror_run (void (*operate
) (void *), void *args
)
44 const char *last_errstring
= NULL
;
47 (void) GLRO(dl_catch_error
) (&objname
, &last_errstring
, operate
, args
);
49 result
= last_errstring
!= NULL
;
50 if (result
&& last_errstring
!= _dl_out_of_memory
)
51 free ((char *) last_errstring
);
56 /* These functions are called by dlerror_run... */
60 /* Argument to do_dlopen. */
65 /* Return from do_dlopen. */
71 /* Arguments to do_dlsym. */
75 /* Return values of do_dlsym. */
83 struct do_dlopen_args
*args
= (struct do_dlopen_args
*) ptr
;
84 /* Open and relocate the shared object. */
85 args
->map
= GLRO(dl_open
) (args
->name
, args
->mode
, NULL
, __LM_ID_CALLER
,
86 __libc_argc
, __libc_argv
, __environ
);
92 struct do_dlsym_args
*args
= (struct do_dlsym_args
*) ptr
;
94 args
->loadbase
= GLRO(dl_lookup_symbol_x
) (args
->name
, args
->map
, &args
->ref
,
95 args
->map
->l_local_scope
, NULL
, 0,
96 DL_LOOKUP_RETURN_NEWEST
, NULL
);
100 do_dlclose (void *ptr
)
102 GLRO(dl_close
) ((struct link_map
*) ptr
);
105 /* This code is to support __libc_dlopen from __libc_dlopen'ed shared
106 libraries. We need to ensure the statically linked __libc_dlopen
107 etc. functions are used instead of the dynamically loaded. */
110 void *(*dlopen_mode
) (const char *name
, int mode
);
111 void *(*dlsym
) (void *map
, const char *name
);
112 int (*dlclose
) (void *map
);
116 extern struct dl_open_hook
*_dl_open_hook
;
117 libc_hidden_proto (_dl_open_hook
);
118 struct dl_open_hook
*_dl_open_hook
__attribute__ ((nocommon
));
119 libc_hidden_data_def (_dl_open_hook
);
122 do_dlsym_private (void *ptr
)
125 struct r_found_version vers
;
126 vers
.name
= "GLIBC_PRIVATE";
128 /* vers.hash = _dl_elf_hash (vers.name); */
129 vers
.hash
= 0x0963cf85;
130 vers
.filename
= NULL
;
132 struct do_dlsym_args
*args
= (struct do_dlsym_args
*) ptr
;
134 l
= GLRO(dl_lookup_symbol_x
) (args
->name
, args
->map
, &args
->ref
,
135 args
->map
->l_scope
, &vers
, 0, 0, NULL
);
139 static struct dl_open_hook _dl_open_hook
=
141 .dlopen_mode
= __libc_dlopen_mode
,
142 .dlsym
= __libc_dlsym
,
143 .dlclose
= __libc_dlclose
147 /* ... and these functions call dlerror_run. */
150 __libc_dlopen_mode (const char *name
, int mode
)
152 struct do_dlopen_args args
;
157 if (__builtin_expect (_dl_open_hook
!= NULL
, 0))
158 return _dl_open_hook
->dlopen_mode (name
, mode
);
159 return (dlerror_run (do_dlopen
, &args
) ? NULL
: (void *) args
.map
);
161 if (dlerror_run (do_dlopen
, &args
))
164 __libc_register_dl_open_hook (args
.map
);
165 __libc_register_dlfcn_hook (args
.map
);
166 return (void *) args
.map
;
169 libc_hidden_def (__libc_dlopen_mode
)
173 __libc_dlsym_private (struct link_map
*map
, const char *name
)
175 struct do_dlsym_args sargs
;
179 if (! dlerror_run (do_dlsym_private
, &sargs
))
180 return DL_SYMBOL_ADDRESS (sargs
.loadbase
, sargs
.ref
);
185 __libc_register_dl_open_hook (struct link_map
*map
)
187 struct dl_open_hook
**hook
;
189 hook
= (struct dl_open_hook
**) __libc_dlsym_private (map
, "_dl_open_hook");
191 *hook
= &_dl_open_hook
;
196 __libc_dlsym (void *map
, const char *name
)
198 struct do_dlsym_args args
;
203 if (__builtin_expect (_dl_open_hook
!= NULL
, 0))
204 return _dl_open_hook
->dlsym (map
, name
);
206 return (dlerror_run (do_dlsym
, &args
) ? NULL
207 : (void *) (DL_SYMBOL_ADDRESS (args
.loadbase
, args
.ref
)));
209 libc_hidden_def (__libc_dlsym
)
212 __libc_dlclose (void *map
)
215 if (__builtin_expect (_dl_open_hook
!= NULL
, 0))
216 return _dl_open_hook
->dlclose (map
);
218 return dlerror_run (do_dlclose
, map
);
220 libc_hidden_def (__libc_dlclose
)
223 libc_freeres_fn (free_mem
)
226 struct r_search_path_elem
*d
;
228 /* Remove all search directories. */
230 while (d
!= GLRO(dl_init_all_dirs
))
232 struct r_search_path_elem
*old
= d
;
237 /* Remove all additional names added to the objects. */
238 for (Lmid_t ns
= 0; ns
< DL_NNS
; ++ns
)
239 for (l
= GL(dl_ns
)[ns
]._ns_loaded
; l
!= NULL
; l
= l
->l_next
)
241 struct libname_list
*lnp
= l
->l_libname
->next
;
243 l
->l_libname
->next
= NULL
;
247 struct libname_list
*old
= lnp
;
249 if (! old
->dont_free
)