1 /* Load a shared object at runtime, relocate it, and run its initializer.
2 Copyright (C) 1996-2004, 2005, 2006, 2007 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
28 #include <sys/mman.h> /* Check whether MAP_COPY is defined. */
29 #include <sys/param.h>
30 #include <bits/libc-lock.h>
34 #include <sysdep-cancel.h>
40 extern ElfW(Addr
) _dl_sysdep_start (void **start_argptr
,
41 void (*dl_main
) (const ElfW(Phdr
) *phdr
,
43 ElfW(Addr
) *user_entry
));
44 weak_extern (BP_SYM (_dl_sysdep_start
))
46 extern int __libc_multiple_libcs
; /* Defined in init-first.c. */
48 /* Undefine the following for debugging. */
49 /* #define SCOPE_DEBUG 1 */
51 static void show_scope (struct link_map
*new);
54 /* We must be carefull not to leave us in an inconsistent state. Thus we
55 catch any error and re-raise it after cleaning up. */
61 /* This is the caller of the dlopen() function. */
62 const void *caller_dlopen
;
63 /* This is the caller if _dl_open(). */
64 const void *caller_dl_open
;
68 /* Original parameters to the program and the current environment. */
76 add_to_global (struct link_map
*new)
78 struct link_map
**new_global
;
79 unsigned int to_add
= 0;
82 /* Count the objects we have to put in the global scope. */
83 for (cnt
= 0; cnt
< new->l_searchlist
.r_nlist
; ++cnt
)
84 if (new->l_searchlist
.r_list
[cnt
]->l_global
== 0)
87 /* The symbols of the new objects and its dependencies are to be
88 introduced into the global scope that will be used to resolve
89 references from other dynamically-loaded objects.
91 The global scope is the searchlist in the main link map. We
92 extend this list if necessary. There is one problem though:
93 since this structure was allocated very early (before the libc
94 is loaded) the memory it uses is allocated by the malloc()-stub
95 in the ld.so. When we come here these functions are not used
96 anymore. Instead the malloc() implementation of the libc is
97 used. But this means the block from the main map cannot be used
98 in an realloc() call. Therefore we allocate a completely new
99 array the first time we have to add something to the locale scope. */
101 struct link_namespaces
*ns
= &GL(dl_ns
)[new->l_ns
];
102 if (ns
->_ns_global_scope_alloc
== 0)
104 /* This is the first dynamic object given global scope. */
105 ns
->_ns_global_scope_alloc
106 = ns
->_ns_main_searchlist
->r_nlist
+ to_add
+ 8;
107 new_global
= (struct link_map
**)
108 malloc (ns
->_ns_global_scope_alloc
* sizeof (struct link_map
*));
109 if (new_global
== NULL
)
111 ns
->_ns_global_scope_alloc
= 0;
113 _dl_signal_error (ENOMEM
, new->l_libname
->name
, NULL
,
114 N_("cannot extend global scope"));
118 /* Copy over the old entries. */
119 ns
->_ns_main_searchlist
->r_list
120 = memcpy (new_global
, ns
->_ns_main_searchlist
->r_list
,
121 (ns
->_ns_main_searchlist
->r_nlist
122 * sizeof (struct link_map
*)));
124 else if (ns
->_ns_main_searchlist
->r_nlist
+ to_add
125 > ns
->_ns_global_scope_alloc
)
127 /* We have to extend the existing array of link maps in the
129 struct link_map
**old_global
130 = GL(dl_ns
)[new->l_ns
]._ns_main_searchlist
->r_list
;
131 size_t new_nalloc
= ((ns
->_ns_global_scope_alloc
+ to_add
) * 2);
133 new_global
= (struct link_map
**)
134 malloc (new_nalloc
* sizeof (struct link_map
*));
135 if (new_global
== NULL
)
138 memcpy (new_global
, old_global
,
139 ns
->_ns_global_scope_alloc
* sizeof (struct link_map
*));
141 ns
->_ns_global_scope_alloc
= new_nalloc
;
142 ns
->_ns_main_searchlist
->r_list
= new_global
;
144 if (!RTLD_SINGLE_THREAD_P
)
145 THREAD_GSCOPE_WAIT ();
150 /* Now add the new entries. */
151 unsigned int new_nlist
= ns
->_ns_main_searchlist
->r_nlist
;
152 for (cnt
= 0; cnt
< new->l_searchlist
.r_nlist
; ++cnt
)
154 struct link_map
*map
= new->l_searchlist
.r_list
[cnt
];
156 if (map
->l_global
== 0)
159 ns
->_ns_main_searchlist
->r_list
[new_nlist
++] = map
;
162 atomic_write_barrier ();
163 ns
->_ns_main_searchlist
->r_nlist
= new_nlist
;
169 _dl_scope_free (struct r_scope_elem
**old
)
171 struct dl_scope_free_list
*fsl
;
172 #define DL_SCOPE_FREE_LIST_SIZE (sizeof (fsl->list) / sizeof (fsl->list[0]))
174 if (RTLD_SINGLE_THREAD_P
)
176 else if ((fsl
= GL(dl_scope_free_list
)) == NULL
)
178 GL(dl_scope_free_list
) = fsl
= malloc (sizeof (*fsl
));
181 THREAD_GSCOPE_WAIT ();
191 else if (fsl
->count
< DL_SCOPE_FREE_LIST_SIZE
)
192 fsl
->list
[fsl
->count
++] = old
;
195 THREAD_GSCOPE_WAIT ();
196 while (fsl
->count
> 0)
197 free (fsl
->list
[--fsl
->count
]);
204 dl_open_worker (void *a
)
206 struct dl_open_args
*args
= a
;
207 const char *file
= args
->file
;
208 int mode
= args
->mode
;
209 struct link_map
*new;
213 bool any_tls
= false;
215 struct link_map
*call_map
= NULL
;
217 /* Check whether _dl_open() has been called from a valid DSO. */
218 if (__check_caller (args
->caller_dl_open
,
219 allow_libc
|allow_libdl
|allow_ldso
) != 0)
220 _dl_signal_error (0, "dlopen", NULL
, N_("invalid caller"));
222 /* Determine the caller's map if necessary. This is needed in case
223 we have a DST, when we don't know the namespace ID we have to put
224 the new object in, or when the file name has no path in which
225 case we need to look along the RUNPATH/RPATH of the caller. */
226 const char *dst
= strchr (file
, '$');
227 if (dst
!= NULL
|| args
->nsid
== __LM_ID_CALLER
228 || strchr (file
, '/') == NULL
)
230 const void *caller_dlopen
= args
->caller_dlopen
;
232 /* We have to find out from which object the caller is calling.
233 By default we assume this is the main application. */
234 call_map
= GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
;
237 for (Lmid_t ns
= 0; ns
< DL_NNS
; ++ns
)
238 for (l
= GL(dl_ns
)[ns
]._ns_loaded
; l
!= NULL
; l
= l
->l_next
)
239 if (caller_dlopen
>= (const void *) l
->l_map_start
240 && caller_dlopen
< (const void *) l
->l_map_end
242 || _dl_addr_inside_object (l
, (ElfW(Addr
)) caller_dlopen
)))
244 assert (ns
== l
->l_ns
);
250 if (args
->nsid
== __LM_ID_CALLER
)
253 /* In statically linked apps there might be no loaded object. */
254 if (call_map
== NULL
)
255 args
->nsid
= LM_ID_BASE
;
258 args
->nsid
= call_map
->l_ns
;
262 assert (_dl_debug_initialize (0, args
->nsid
)->r_state
== RT_CONSISTENT
);
264 /* Maybe we have to expand a DST. */
265 if (__builtin_expect (dst
!= NULL
, 0))
267 size_t len
= strlen (file
);
271 /* Determine how much space we need. We have to allocate the
273 required
= DL_DST_REQUIRED (call_map
, file
, len
, _dl_dst_count (dst
, 0));
275 /* Get space for the new file name. */
276 new_file
= (char *) alloca (required
+ 1);
278 /* Generate the new file name. */
279 _dl_dst_substitute (call_map
, file
, new_file
, 0);
281 /* If the substitution failed don't try to load. */
282 if (*new_file
== '\0')
283 _dl_signal_error (0, "dlopen", NULL
,
284 N_("empty dynamic string token substitution"));
286 /* Now we have a new file name. */
289 /* It does not matter whether call_map is set even if we
290 computed it only because of the DST. Since the path contains
291 a slash the value is not used. See dl-load.c. */
294 /* Load the named object. */
295 args
->map
= new = _dl_map_object (call_map
, file
, 0, lt_loaded
, 0,
296 mode
| __RTLD_CALLMAP
, args
->nsid
);
298 /* If the pointer returned is NULL this means the RTLD_NOLOAD flag is
299 set and the object is not already loaded. */
302 assert (mode
& RTLD_NOLOAD
);
306 if (__builtin_expect (mode
& __RTLD_SPROF
, 0))
307 /* This happens only if we load a DSO for 'sprof'. */
310 /* This object is directly loaded. */
311 ++new->l_direct_opencount
;
313 /* It was already open. */
314 if (__builtin_expect (new->l_searchlist
.r_list
!= NULL
, 0))
316 /* Let the user know about the opencount. */
317 if (__builtin_expect (GLRO(dl_debug_mask
) & DL_DEBUG_FILES
, 0))
318 _dl_debug_printf ("opening file=%s [%lu]; direct_opencount=%u\n\n",
319 new->l_name
, new->l_ns
, new->l_direct_opencount
);
321 /* If the user requested the object to be in the global namespace
322 but it is not so far, add it now. */
323 if ((mode
& RTLD_GLOBAL
) && new->l_global
== 0)
324 (void) add_to_global (new);
326 assert (_dl_debug_initialize (0, args
->nsid
)->r_state
== RT_CONSISTENT
);
331 /* Load that object's dependencies. */
332 _dl_map_object_deps (new, NULL
, 0, 0,
333 mode
& (__RTLD_DLOPEN
| RTLD_DEEPBIND
| __RTLD_AUDIT
));
335 /* So far, so good. Now check the versions. */
336 for (i
= 0; i
< new->l_searchlist
.r_nlist
; ++i
)
337 if (new->l_searchlist
.r_list
[i
]->l_real
->l_versions
== NULL
)
338 (void) _dl_check_map_versions (new->l_searchlist
.r_list
[i
]->l_real
,
346 /* Auditing checkpoint: we have added all objects. */
347 if (__builtin_expect (GLRO(dl_naudit
) > 0, 0))
349 struct link_map
*head
= GL(dl_ns
)[new->l_ns
]._ns_loaded
;
350 /* Do not call the functions for any auditing object. */
351 if (head
->l_auditing
== 0)
353 struct audit_ifaces
*afct
= GLRO(dl_audit
);
354 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
356 if (afct
->activity
!= NULL
)
357 afct
->activity (&head
->l_audit
[cnt
].cookie
, LA_ACT_CONSISTENT
);
365 /* Notify the debugger all new objects are now ready to go. */
366 struct r_debug
*r
= _dl_debug_initialize (0, args
->nsid
);
367 r
->r_state
= RT_CONSISTENT
;
370 /* Only do lazy relocation if `LD_BIND_NOW' is not set. */
371 lazy
= (mode
& RTLD_BINDING_MASK
) == RTLD_LAZY
&& GLRO(dl_lazy
);
373 /* Relocate the objects loaded. We do this in reverse order so that copy
374 relocs of earlier objects overwrite the data written by later objects. */
376 struct link_map
*l
= new;
381 if (! l
->l_real
->l_relocated
)
384 if (__builtin_expect (GLRO(dl_profile
) != NULL
, 0))
386 /* If this here is the shared object which we want to profile
387 make sure the profile is started. We can find out whether
388 this is necessary or not by observing the `_dl_profile_map'
389 variable. If was NULL but is not NULL afterwars we must
390 start the profiling. */
391 struct link_map
*old_profile_map
= GL(dl_profile_map
);
393 _dl_relocate_object (l
, l
->l_scope
, 1, 1);
395 if (old_profile_map
== NULL
&& GL(dl_profile_map
) != NULL
)
397 /* We must prepare the profiling. */
398 _dl_start_profile ();
400 /* Prevent unloading the object. */
401 GL(dl_profile_map
)->l_flags_1
|= DF_1_NODELETE
;
406 _dl_relocate_object (l
, l
->l_scope
, lazy
, 0);
414 /* If the file is not loaded now as a dependency, add the search
415 list of the newly loaded object to the scope. */
416 for (i
= 0; i
< new->l_searchlist
.r_nlist
; ++i
)
418 struct link_map
*imap
= new->l_searchlist
.r_list
[i
];
420 /* If the initializer has been called already, the object has
421 not been loaded here and now. */
422 if (imap
->l_init_called
&& imap
->l_type
== lt_loaded
)
424 struct r_scope_elem
**runp
= imap
->l_scope
;
427 while (*runp
!= NULL
)
429 if (*runp
== &new->l_searchlist
)
436 /* Avoid duplicates. */
439 if (__builtin_expect (cnt
+ 1 >= imap
->l_scope_max
, 0))
441 /* The 'r_scope' array is too small. Allocate a new one
444 struct r_scope_elem
**newp
;
446 #define SCOPE_ELEMS(imap) \
447 (sizeof (imap->l_scope_mem) / sizeof (imap->l_scope_mem[0]))
449 if (imap
->l_scope
!= imap
->l_scope_mem
450 && imap
->l_scope_max
< SCOPE_ELEMS (imap
))
452 new_size
= SCOPE_ELEMS (imap
);
453 newp
= imap
->l_scope_mem
;
457 new_size
= imap
->l_scope_max
* 2;
458 newp
= (struct r_scope_elem
**)
459 malloc (new_size
* sizeof (struct r_scope_elem
*));
461 _dl_signal_error (ENOMEM
, "dlopen", NULL
,
462 N_("cannot create scope list"));
465 memcpy (newp
, imap
->l_scope
, cnt
* sizeof (imap
->l_scope
[0]));
466 struct r_scope_elem
**old
= imap
->l_scope
;
468 imap
->l_scope
= newp
;
470 if (old
!= imap
->l_scope_mem
)
471 _dl_scope_free (old
);
473 imap
->l_scope_max
= new_size
;
476 /* First terminate the extended list. Otherwise a thread
477 might use the new last element and then use the garbage
479 imap
->l_scope
[cnt
+ 1] = NULL
;
480 atomic_write_barrier ();
481 imap
->l_scope
[cnt
] = &new->l_searchlist
;
484 /* Only add TLS memory if this object is loaded now and
485 therefore is not yet initialized. */
486 else if (! imap
->l_init_called
487 /* Only if the module defines thread local data. */
488 && __builtin_expect (imap
->l_tls_blocksize
> 0, 0))
490 /* Now that we know the object is loaded successfully add
491 modules containing TLS data to the slot info table. We
492 might have to increase its size. */
493 _dl_add_to_slotinfo (imap
);
495 if (imap
->l_need_tls_init
)
497 imap
->l_need_tls_init
= 0;
499 /* Update the slot information data for at least the
500 generation of the DSO we are allocating data for. */
501 _dl_update_slotinfo (imap
->l_tls_modid
);
504 GL(dl_init_static_tls
) (imap
);
505 assert (imap
->l_need_tls_init
== 0);
508 /* We have to bump the generation counter. */
515 /* Bump the generation number if necessary. */
516 if (any_tls
&& __builtin_expect (++GL(dl_tls_generation
) == 0, 0))
517 _dl_fatal_printf (N_("\
518 TLS generation counter wrapped! Please report this."));
521 /* Run the initializer functions of new objects. */
522 _dl_init (new, args
->argc
, args
->argv
, args
->env
);
524 /* Now we can make the new map available in the global scope. */
525 if (mode
& RTLD_GLOBAL
)
526 /* Move the object in the global namespace. */
527 if (add_to_global (new) != 0)
531 /* Mark the object as not deletable if the RTLD_NODELETE flags was
533 if (__builtin_expect (mode
& RTLD_NODELETE
, 0))
534 new->l_flags_1
|= DF_1_NODELETE
;
537 /* We must be the static _dl_open in libc.a. A static program that
538 has loaded a dynamic object now has competition. */
539 __libc_multiple_libcs
= 1;
542 /* Let the user know about the opencount. */
543 if (__builtin_expect (GLRO(dl_debug_mask
) & DL_DEBUG_FILES
, 0))
544 _dl_debug_printf ("opening file=%s [%lu]; direct_opencount=%u\n\n",
545 new->l_name
, new->l_ns
, new->l_direct_opencount
);
550 _dl_open (const char *file
, int mode
, const void *caller_dlopen
, Lmid_t nsid
,
551 int argc
, char *argv
[], char *env
[])
553 if ((mode
& RTLD_BINDING_MASK
) == 0)
554 /* One of the flags must be set. */
555 _dl_signal_error (EINVAL
, file
, NULL
, N_("invalid mode for dlopen()"));
557 /* Make sure we are alone. */
558 __rtld_lock_lock_recursive (GL(dl_load_lock
));
560 if (nsid
== LM_ID_NEWLM
)
562 /* Find a new namespace. */
563 for (nsid
= 1; nsid
< DL_NNS
; ++nsid
)
564 if (GL(dl_ns
)[nsid
]._ns_loaded
== NULL
)
569 /* No more namespace available. */
570 __rtld_lock_unlock_recursive (GL(dl_load_lock
));
572 _dl_signal_error (EINVAL
, file
, NULL
, N_("\
573 no more namespaces available for dlmopen()"));
576 _dl_debug_initialize (0, nsid
)->r_state
= RT_CONSISTENT
;
578 /* Never allow loading a DSO in a namespace which is empty. Such
579 direct placements is only causing problems. Also don't allow
580 loading into a namespace used for auditing. */
581 else if (nsid
!= LM_ID_BASE
&& nsid
!= __LM_ID_CALLER
582 && (GL(dl_ns
)[nsid
]._ns_nloaded
== 0
583 || GL(dl_ns
)[nsid
]._ns_loaded
->l_auditing
))
584 _dl_signal_error (EINVAL
, file
, NULL
,
585 N_("invalid target namespace in dlmopen()"));
587 struct dl_open_args args
;
590 args
.caller_dlopen
= caller_dlopen
;
591 args
.caller_dl_open
= RETURN_ADDRESS (0);
599 const char *errstring
;
601 int errcode
= _dl_catch_error (&objname
, &errstring
, &malloced
,
602 dl_open_worker
, &args
);
605 /* We must munmap() the cache file. */
609 /* See if an error occurred during loading. */
610 if (__builtin_expect (errstring
!= NULL
, 0))
612 /* Remove the object from memory. It may be in an inconsistent
613 state if relocation failed, for example. */
617 /* Maybe some of the modules which were loaded use TLS.
618 Since it will be removed in the following _dl_close call
619 we have to mark the dtv array as having gaps to fill the
620 holes. This is a pessimistic assumption which won't hurt
621 if not true. There is no need to do this when we are
622 loading the auditing DSOs since TLS has not yet been set
624 if ((mode
& __RTLD_AUDIT
) == 0)
625 GL(dl_tls_dtv_gaps
) = true;
628 _dl_close_worker (args
.map
);
631 assert (_dl_debug_initialize (0, args
.nsid
)->r_state
== RT_CONSISTENT
);
633 /* Release the lock. */
634 __rtld_lock_unlock_recursive (GL(dl_load_lock
));
636 /* Make a local copy of the error string so that we can release the
637 memory allocated for it. */
638 size_t len_errstring
= strlen (errstring
) + 1;
639 char *local_errstring
;
640 if (objname
== errstring
+ len_errstring
)
642 size_t total_len
= len_errstring
+ strlen (objname
) + 1;
643 local_errstring
= alloca (total_len
);
644 memcpy (local_errstring
, errstring
, total_len
);
645 objname
= local_errstring
+ len_errstring
;
649 local_errstring
= alloca (len_errstring
);
650 memcpy (local_errstring
, errstring
, len_errstring
);
654 free ((char *) errstring
);
656 /* Reraise the error. */
657 _dl_signal_error (errcode
, objname
, NULL
, local_errstring
);
660 assert (_dl_debug_initialize (0, args
.nsid
)->r_state
== RT_CONSISTENT
);
662 /* Release the lock. */
663 __rtld_lock_unlock_recursive (GL(dl_load_lock
));
666 DL_STATIC_INIT (args
.map
);
677 show_scope (struct link_map
*new)
681 for (scope_cnt
= 0; new->l_scope
[scope_cnt
] != NULL
; ++scope_cnt
)
686 numbuf
[0] = '0' + scope_cnt
;
688 _dl_printf ("scope %s:", numbuf
);
690 for (cnt
= 0; cnt
< new->l_scope
[scope_cnt
]->r_nlist
; ++cnt
)
691 if (*new->l_scope
[scope_cnt
]->r_list
[cnt
]->l_name
)
692 _dl_printf (" %s", new->l_scope
[scope_cnt
]->r_list
[cnt
]->l_name
);
694 _dl_printf (" <main>");
702 /* Return non-zero if ADDR lies within one of L's segments. */
705 _dl_addr_inside_object (struct link_map
*l
, const ElfW(Addr
) addr
)
708 const ElfW(Addr
) reladdr
= addr
- l
->l_addr
;
711 if (l
->l_phdr
[n
].p_type
== PT_LOAD
712 && reladdr
- l
->l_phdr
[n
].p_vaddr
>= 0
713 && reladdr
- l
->l_phdr
[n
].p_vaddr
< l
->l_phdr
[n
].p_memsz
)