1 /* Load the dependencies of a mapped object.
2 Copyright (C) 1996, 1997, 1998, 1999 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 Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 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 Library General Public License for more details.
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If not,
17 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA. */
26 #include <sys/param.h>
27 #include <elf/ldsodefs.h>
31 /* Whether an shared object references one or more auxiliary objects
32 is signaled by the AUXTAG entry in l_info. */
33 #define AUXTAG (DT_NUM + DT_PROCNUM + DT_VERSIONTAGNUM \
34 + DT_EXTRATAGIDX (DT_AUXILIARY))
35 /* Whether an shared object references one or more auxiliary objects
36 is signaled by the AUXTAG entry in l_info. */
37 #define FILTERTAG (DT_NUM + DT_PROCNUM + DT_VERSIONTAGNUM \
38 + DT_EXTRATAGIDX (DT_FILTER))
40 /* This is zero at program start to signal that the global scope map is
41 allocated by rtld. Later it keeps the size of the map. It might be
42 reset if in _dl_close if the last global object is removed. */
43 size_t _dl_global_scope_alloc
;
45 extern size_t _dl_platformlen
;
47 /* When loading auxiliary objects we must ignore errors. It's ok if
48 an object is missing. */
51 /* The arguments to openaux. */
57 /* The return value of openaux. */
64 struct openaux_args
*args
= (struct openaux_args
*) a
;
66 args
->aux
= _dl_map_object (args
->map
, args
->name
, 0,
67 (args
->map
->l_type
== lt_executable
68 ? lt_library
: args
->map
->l_type
),
74 /* We use a very special kind of list to track the two kinds paths
75 through the list of loaded shared objects. We have to
77 - produce a flat list with unique members of all involved objects
79 - produce a flat list of all shared objects.
83 int done
; /* Nonzero if this map was processed. */
84 struct link_map
*map
; /* The data. */
86 struct list
*unique
; /* Elements for normal list. */
87 struct list
*dup
; /* Elements in complete list. */
91 /* Macro to expand DST. It is an macro since we use `alloca'. */
92 #define expand_dst(l, str, fatal) \
94 const char *__str = (str); \
95 const char *__result = __str; \
96 size_t __cnt = DL_DST_COUNT(__str, 0); \
102 /* DST must not appear in SUID/SGID programs. */ \
103 if (__libc_enable_secure) \
104 _dl_signal_error (0, __str, \
105 "DST not allowed in SUID/SGID programs"); \
107 __newp = (char *) alloca (DL_DST_REQUIRED (l, __str, strlen (__str), \
110 __result = DL_DST_SUBSTITUTE (l, __str, __newp, 0); \
112 if (*__result == '\0') \
114 /* The replacement for the DST is not known. We can't \
117 _dl_signal_error (0, __str, \
118 "empty dynamics string token substitution"); \
121 /* This is for DT_AUXILIARY. */ \
122 if (_dl_debug_libs) \
123 _dl_debug_message (1, "cannot load auxiliary `", __str, \
124 "' because of empty dynamic string" \
125 " token substitution\n", NULL); \
136 _dl_map_object_deps (struct link_map
*map
,
137 struct link_map
**preloads
, unsigned int npreloads
,
138 int trace_mode
, int global_scope
)
140 struct list known
[1 + npreloads
+ 1];
141 struct list
*runp
, *utail
, *dtail
;
142 unsigned int nlist
, nduplist
, i
;
143 unsigned int to_add
= 0;
145 inline void preload (struct link_map
*map
)
147 known
[nlist
].done
= 0;
148 known
[nlist
].map
= map
;
150 known
[nlist
].unique
= &known
[nlist
+ 1];
151 known
[nlist
].dup
= &known
[nlist
+ 1];
154 /* We use `l_reserved' as a mark bit to detect objects we have
155 already put in the search list and avoid adding duplicate
156 elements later in the list. */
160 /* No loaded object so far. */
163 /* First load MAP itself. */
166 /* Add the preloaded items after MAP but before any of its dependencies. */
167 for (i
= 0; i
< npreloads
; ++i
)
168 preload (preloads
[i
]);
170 /* Terminate the lists. */
171 known
[nlist
- 1].unique
= NULL
;
172 known
[nlist
- 1].dup
= NULL
;
174 /* Pointer to last unique object. */
175 utail
= &known
[nlist
- 1];
176 /* Pointer to last loaded object. */
177 dtail
= &known
[nlist
- 1];
179 /* Until now we have the same number of libraries in the normal and
180 the list with duplicates. */
183 /* Process each element of the search list, loading each of its
184 auxiliary objects and immediate dependencies. Auxiliary objects
185 will be added in the list before the object itself and
186 dependencies will be appended to the list as we step through it.
187 This produces a flat, ordered list that represents a
188 breadth-first search of the dependency tree.
190 The whole process is complicated by the fact that we better
191 should use alloca for the temporary list elements. But using
192 alloca means we cannot use recursive function calls. */
193 for (runp
= known
; runp
; )
195 struct link_map
*l
= runp
->map
;
197 if (l
->l_info
[DT_NEEDED
] || l
->l_info
[AUXTAG
] || l
->l_info
[FILTERTAG
])
199 const char *strtab
= (const void *) l
->l_info
[DT_STRTAB
]->d_un
.d_ptr
;
200 struct openaux_args args
;
204 /* Mark map as processed. */
207 args
.strtab
= strtab
;
209 args
.trace_mode
= trace_mode
;
212 for (d
= l
->l_ld
; d
->d_tag
!= DT_NULL
; ++d
)
213 if (__builtin_expect (d
->d_tag
, DT_NEEDED
) == DT_NEEDED
)
215 /* Map in the needed object. */
216 struct link_map
*dep
;
217 /* Allocate new entry. */
222 /* Recognize DSTs. */
223 name
= expand_dst (l
, strtab
+ d
->d_un
.d_val
, 0);
225 dep
= _dl_map_object (l
, name
, 0,
226 l
->l_type
== lt_executable
? lt_library
:
227 l
->l_type
, trace_mode
);
229 /* Add it in any case to the duplicate list. */
230 newp
= alloca (sizeof (struct list
));
238 /* This object is already in the search list we are
239 building. Don't add a duplicate pointer.
240 Release the reference just added by
245 /* Append DEP to the unique list. */
248 utail
->unique
= newp
;
251 /* Set the mark bit that says it's already in the list. */
255 else if (d
->d_tag
== DT_AUXILIARY
|| d
->d_tag
== DT_FILTER
)
262 /* Recognize DSTs. */
263 name
= expand_dst (l
, strtab
+ d
->d_un
.d_val
,
264 d
->d_tag
== DT_AUXILIARY
);
266 if (d
->d_tag
== DT_AUXILIARY
)
268 /* Store the tag in the argument structure. */
271 /* Say that we are about to load an auxiliary library. */
273 _dl_debug_message (1, "load auxiliary object=",
274 name
, " requested by file=",
276 ? l
->l_name
: _dl_argv
[0],
279 /* We must be prepared that the addressed shared
280 object is not available. */
281 if (_dl_catch_error (&errstring
, openaux
, &args
))
283 /* We are not interested in the error message. */
284 assert (errstring
!= NULL
);
287 /* Simply ignore this error and continue the work. */
293 /* Say that we are about to load an auxiliary library. */
295 _dl_debug_message (1, "load filtered object=", name
,
296 " requested by file=",
298 ? l
->l_name
: _dl_argv
[0],
301 /* For filter objects the dependency must be available. */
302 args
.aux
= _dl_map_object (l
, name
, 0,
303 (l
->l_type
== lt_executable
304 ? lt_library
: l
->l_type
),
308 /* The auxiliary object is actually available.
309 Incorporate the map in all the lists. */
311 /* Allocate new entry. This always has to be done. */
312 newp
= alloca (sizeof (struct list
));
314 /* We want to insert the new map before the current one,
315 but we have no back links. So we copy the contents of
316 the current entry over. Note that ORIG and NEWP now
317 have switched their meanings. */
318 orig
->dup
= memcpy (newp
, orig
, sizeof (*newp
));
320 /* Initialize new entry. */
322 orig
->map
= args
.aux
;
324 /* We must handle two situations here: the map is new,
325 so we must add it in all three lists. If the map
326 is already known, we have two further possibilities:
327 - if the object is before the current map in the
328 search list, we do nothing. It is already found
330 - if the object is after the current one, we must
331 move it just before the current map to make sure
332 the symbols are found early enough
334 if (args
.aux
->l_reserved
)
336 /* The object is already somewhere in the list.
340 /* This object is already in the search list we
341 are building. Don't add a duplicate pointer.
342 Release the reference just added by
344 --args
.aux
->l_opencount
;
346 for (late
= newp
; late
->unique
; late
= late
->unique
)
347 if (late
->unique
->map
== args
.aux
)
352 /* The object is somewhere behind the current
353 position in the search path. We have to
354 move it to this earlier position. */
357 /* Now remove the later entry from the unique list
358 and adjust the tail pointer. */
359 if (utail
== late
->unique
)
361 late
->unique
= late
->unique
->unique
;
363 /* We must move the object earlier in the chain. */
364 if (args
.aux
->l_prev
)
365 args
.aux
->l_prev
->l_next
= args
.aux
->l_next
;
366 if (args
.aux
->l_next
)
367 args
.aux
->l_next
->l_prev
= args
.aux
->l_prev
;
369 args
.aux
->l_prev
= newp
->map
->l_prev
;
370 newp
->map
->l_prev
= args
.aux
;
371 if (args
.aux
->l_prev
!= NULL
)
372 args
.aux
->l_prev
->l_next
= args
.aux
;
373 args
.aux
->l_next
= newp
->map
;
377 /* The object must be somewhere earlier in the
378 list. That's good, we only have to insert
379 an entry for the duplicate list. */
380 orig
->unique
= NULL
; /* Never used. */
382 /* Now we have a problem. The element
383 pointing to ORIG in the unique list must
384 point to NEWP now. This is the only place
385 where we need this backreference and this
386 situation is really not that frequent. So
387 we don't use a double-linked list but
388 instead search for the preceding element. */
390 while (late
->unique
!= orig
)
397 /* This is easy. We just add the symbol right here. */
400 /* Set the mark bit that says it's already in the list. */
401 args
.aux
->l_reserved
= 1;
403 /* The only problem is that in the double linked
404 list of all objects we don't have this new
405 object at the correct place. Correct this here. */
406 if (args
.aux
->l_prev
)
407 args
.aux
->l_prev
->l_next
= args
.aux
->l_next
;
408 if (args
.aux
->l_next
)
409 args
.aux
->l_next
->l_prev
= args
.aux
->l_prev
;
411 args
.aux
->l_prev
= newp
->map
->l_prev
;
412 newp
->map
->l_prev
= args
.aux
;
413 if (args
.aux
->l_prev
!= NULL
)
414 args
.aux
->l_prev
->l_next
= args
.aux
;
415 args
.aux
->l_next
= newp
->map
;
418 /* Move the tail pointers if necessary. */
424 /* Move on the insert point. */
427 /* We always add an entry to the duplicate list. */
432 /* Mark as processed. */
435 /* If we have no auxiliary objects just go on to the next map. */
439 while (runp
!= NULL
&& runp
->done
);
442 /* Store the search list we built in the object. It will be used for
443 searches in the scope of this object. */
444 map
->l_searchlist
.r_list
= malloc (nlist
* sizeof (struct link_map
*));
445 if (map
->l_searchlist
.r_list
== NULL
)
446 _dl_signal_error (ENOMEM
, map
->l_name
,
447 "cannot allocate symbol search list");
448 map
->l_searchlist
.r_nlist
= nlist
;
450 for (nlist
= 0, runp
= known
; runp
; runp
= runp
->unique
)
452 if (trace_mode
&& runp
->map
->l_opencount
== 0)
453 /* This can happen when we trace the loading. */
454 --map
->l_searchlist
.r_nlist
;
456 map
->l_searchlist
.r_list
[nlist
++] = runp
->map
;
458 /* Now clear all the mark bits we set in the objects on the search list
459 to avoid duplicates, so the next call starts fresh. */
460 runp
->map
->l_reserved
= 0;
463 map
->l_searchlist
.r_nduplist
= nduplist
;
464 if (nlist
== nduplist
)
465 map
->l_searchlist
.r_duplist
= map
->l_searchlist
.r_list
;
470 map
->l_searchlist
.r_duplist
= malloc (nduplist
471 * sizeof (struct link_map
*));
472 if (map
->l_searchlist
.r_duplist
== NULL
)
473 _dl_signal_error (ENOMEM
, map
->l_name
,
474 "cannot allocate symbol search list");
476 for (cnt
= 0, runp
= known
; runp
; runp
= runp
->dup
)
477 if (trace_mode
&& runp
->map
->l_opencount
== 0)
478 /* This can happen when we trace the loading. */
479 --map
->l_searchlist
.r_nduplist
;
481 map
->l_searchlist
.r_duplist
[cnt
++] = runp
->map
;
484 /* Now that all this succeeded put the objects in the global scope if
485 this is necessary. We put the original object and all the dependencies
486 in the global scope. If an object is already loaded and not in the
487 global scope we promote it. */
491 struct link_map
**new_global
;
493 /* Count the objects we have to put in the global scope. */
494 for (cnt
= 0; cnt
< nlist
; ++cnt
)
495 if (map
->l_searchlist
.r_list
[cnt
]->l_global
== 0)
498 /* The symbols of the new objects and its dependencies are to be
499 introduced into the global scope that will be used to resolve
500 references from other dynamically-loaded objects.
502 The global scope is the searchlist in the main link map. We
503 extend this list if necessary. There is one problem though:
504 since this structure was allocated very early (before the libc
505 is loaded) the memory it uses is allocated by the malloc()-stub
506 in the ld.so. When we come here these functions are not used
507 anymore. Instead the malloc() implementation of the libc is
508 used. But this means the block from the main map cannot be used
509 in an realloc() call. Therefore we allocate a completely new
510 array the first time we have to add something to the locale scope. */
512 if (_dl_global_scope_alloc
== 0)
514 /* This is the first dynamic object given global scope. */
515 _dl_global_scope_alloc
= _dl_main_searchlist
->r_nlist
+ to_add
+ 8;
516 new_global
= (struct link_map
**)
517 malloc (_dl_global_scope_alloc
* sizeof (struct link_map
*));
518 if (new_global
== NULL
)
520 _dl_global_scope_alloc
= 0;
522 _dl_signal_error (ENOMEM
, map
->l_libname
->name
,
523 "cannot extend global scope");
527 /* Copy over the old entries. */
528 memcpy (new_global
, _dl_main_searchlist
->r_list
,
529 (_dl_main_searchlist
->r_nlist
* sizeof (struct link_map
*)));
531 _dl_main_searchlist
->r_list
= new_global
;
533 else if (_dl_main_searchlist
->r_nlist
+ to_add
> _dl_global_scope_alloc
)
535 /* We have to extend the existing array of link maps in the
537 new_global
= (struct link_map
**)
538 realloc (_dl_main_searchlist
->r_list
,
539 ((_dl_global_scope_alloc
+ to_add
+ 8)
540 * sizeof (struct link_map
*)));
541 if (new_global
== NULL
)
544 _dl_global_scope_alloc
+= to_add
+ 8;
545 _dl_main_searchlist
->r_list
= new_global
;
548 /* Now add the new entries. */
550 for (cnt
= 0; cnt
< nlist
; ++cnt
)
551 if (map
->l_searchlist
.r_list
[cnt
]->l_global
== 0)
553 _dl_main_searchlist
->r_list
[_dl_main_searchlist
->r_nlist
+ to_add
]
554 = map
->l_searchlist
.r_list
[cnt
];
558 /* XXX Do we have to add something to r_dupsearchlist??? --drepper */