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git.ipfire.org Git - thirdparty/glibc.git/blob - elf/dl-deps.c
1 /* Load the dependencies of a mapped object.
2 Copyright (C) 1996, 1997, 1998, 1999, 2000 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. */
27 #include <sys/param.h>
32 /* Whether an shared object references one or more auxiliary objects
33 is signaled by the AUXTAG entry in l_info. */
34 #define AUXTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
35 + DT_EXTRATAGIDX (DT_AUXILIARY))
36 /* Whether an shared object references one or more auxiliary objects
37 is signaled by the AUXTAG entry in l_info. */
38 #define FILTERTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
39 + DT_EXTRATAGIDX (DT_FILTER))
41 /* This is zero at program start to signal that the global scope map is
42 allocated by rtld. Later it keeps the size of the map. It might be
43 reset if in _dl_close if the last global object is removed. */
44 size_t _dl_global_scope_alloc
;
46 extern size_t _dl_platformlen
;
48 /* When loading auxiliary objects we must ignore errors. It's ok if
49 an object is missing. */
52 /* The arguments to openaux. */
58 /* The return value of openaux. */
65 struct openaux_args
*args
= (struct openaux_args
*) a
;
67 args
->aux
= _dl_map_object (args
->map
, args
->name
, 0,
68 (args
->map
->l_type
== lt_executable
69 ? lt_library
: args
->map
->l_type
),
75 /* We use a very special kind of list to track the two kinds paths
76 through the list of loaded shared objects. We have to
78 - produce a flat list with unique members of all involved objects
80 - produce a flat list of all shared objects.
84 int done
; /* Nonzero if this map was processed. */
85 struct link_map
*map
; /* The data. */
87 struct list
*unique
; /* Elements for normal list. */
88 struct list
*dup
; /* Elements in complete list. */
92 /* Macro to expand DST. It is an macro since we use `alloca'. */
93 #define expand_dst(l, str, fatal) \
95 const char *__str = (str); \
96 const char *__result = __str; \
97 size_t __cnt = DL_DST_COUNT(__str, 0); \
103 /* DST must not appear in SUID/SGID programs. */ \
104 if (__libc_enable_secure) \
105 _dl_signal_error (0, __str, \
106 N_("DST not allowed in SUID/SGID programs")); \
108 __newp = (char *) alloca (DL_DST_REQUIRED (l, __str, strlen (__str), \
111 __result = DL_DST_SUBSTITUTE (l, __str, __newp, 0); \
113 if (*__result == '\0') \
115 /* The replacement for the DST is not known. We can't \
118 _dl_signal_error (0, __str, N_("\
119 empty dynamics string token substitution")); \
122 /* This is for DT_AUXILIARY. */ \
123 if (__builtin_expect (_dl_debug_libs, 0)) \
124 _dl_debug_message (1, "cannot load auxiliary `", __str, \
125 "' because of empty dynamic string" \
126 " token substitution\n", NULL); \
137 _dl_map_object_deps (struct link_map
*map
,
138 struct link_map
**preloads
, unsigned int npreloads
,
141 struct list known
[1 + npreloads
+ 1];
142 struct list
*runp
, *utail
, *dtail
;
143 unsigned int nlist
, nduplist
, i
;
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
;
196 struct link_map
**needed
= NULL
;
197 unsigned int nneeded
= 0;
199 /* Unless otherwise stated, this object is handled. */
202 /* Allocate a temporary record to contain the references to the
203 dependencies of this object. */
204 if (l
->l_searchlist
.r_list
== NULL
&& l
!= map
&& l
->l_ldnum
> 0)
205 needed
= (struct link_map
**) alloca (l
->l_ldnum
206 * sizeof (struct link_map
*));
208 if (l
->l_info
[DT_NEEDED
] || l
->l_info
[AUXTAG
] || l
->l_info
[FILTERTAG
])
210 const char *strtab
= (const void *) D_PTR (l
, l_info
[DT_STRTAB
]);
211 struct openaux_args args
;
215 args
.strtab
= strtab
;
217 args
.trace_mode
= trace_mode
;
220 for (d
= l
->l_ld
; d
->d_tag
!= DT_NULL
; ++d
)
221 if (__builtin_expect (d
->d_tag
, DT_NEEDED
) == DT_NEEDED
)
223 /* Map in the needed object. */
224 struct link_map
*dep
;
225 /* Allocate new entry. */
230 /* Recognize DSTs. */
231 name
= expand_dst (l
, strtab
+ d
->d_un
.d_val
, 0);
233 dep
= _dl_map_object (l
, name
, 0,
234 l
->l_type
== lt_executable
? lt_library
:
235 l
->l_type
, trace_mode
);
237 /* Add it in any case to the duplicate list. */
238 newp
= alloca (sizeof (struct list
));
246 /* This object is already in the search list we are
247 building. Don't add a duplicate pointer.
248 Release the reference just added by
253 /* Append DEP to the unique list. */
256 utail
->unique
= newp
;
259 /* Set the mark bit that says it's already in the list. */
263 /* Remember this dependency. */
265 needed
[nneeded
++] = dep
;
267 else if (d
->d_tag
== DT_AUXILIARY
|| d
->d_tag
== DT_FILTER
)
270 const char *errstring
;
275 /* Recognize DSTs. */
276 name
= expand_dst (l
, strtab
+ d
->d_un
.d_val
,
277 d
->d_tag
== DT_AUXILIARY
);
279 if (d
->d_tag
== DT_AUXILIARY
)
281 /* Store the tag in the argument structure. */
284 /* Say that we are about to load an auxiliary library. */
285 if (__builtin_expect (_dl_debug_libs
, 0))
286 _dl_debug_message (1, "load auxiliary object=",
287 name
, " requested by file=",
289 ? l
->l_name
: _dl_argv
[0],
292 /* We must be prepared that the addressed shared
293 object is not available. */
294 if (_dl_catch_error (&objname
, &errstring
, openaux
, &args
))
296 /* We are not interested in the error message. */
297 assert (errstring
!= NULL
);
298 free ((char *) errstring
);
300 /* Simply ignore this error and continue the work. */
306 /* Say that we are about to load an auxiliary library. */
307 if (__builtin_expect (_dl_debug_libs
, 0))
308 _dl_debug_message (1, "load filtered object=", name
,
309 " requested by file=",
311 ? l
->l_name
: _dl_argv
[0],
314 /* For filter objects the dependency must be available. */
315 args
.aux
= _dl_map_object (l
, name
, 0,
316 (l
->l_type
== lt_executable
317 ? lt_library
: l
->l_type
),
321 /* The auxiliary object is actually available.
322 Incorporate the map in all the lists. */
324 /* Allocate new entry. This always has to be done. */
325 newp
= alloca (sizeof (struct list
));
327 /* We want to insert the new map before the current one,
328 but we have no back links. So we copy the contents of
329 the current entry over. Note that ORIG and NEWP now
330 have switched their meanings. */
331 orig
->dup
= memcpy (newp
, orig
, sizeof (*newp
));
333 /* Initialize new entry. */
335 orig
->map
= args
.aux
;
337 /* Remember this dependency. */
339 needed
[nneeded
++] = args
.aux
;
341 /* We must handle two situations here: the map is new,
342 so we must add it in all three lists. If the map
343 is already known, we have two further possibilities:
344 - if the object is before the current map in the
345 search list, we do nothing. It is already found
347 - if the object is after the current one, we must
348 move it just before the current map to make sure
349 the symbols are found early enough
351 if (args
.aux
->l_reserved
)
353 /* The object is already somewhere in the list.
357 /* This object is already in the search list we
358 are building. Don't add a duplicate pointer.
359 Release the reference just added by
361 --args
.aux
->l_opencount
;
363 for (late
= newp
; late
->unique
; late
= late
->unique
)
364 if (late
->unique
->map
== args
.aux
)
369 /* The object is somewhere behind the current
370 position in the search path. We have to
371 move it to this earlier position. */
374 /* Now remove the later entry from the unique list
375 and adjust the tail pointer. */
376 if (utail
== late
->unique
)
378 late
->unique
= late
->unique
->unique
;
380 /* We must move the object earlier in the chain. */
381 if (args
.aux
->l_prev
)
382 args
.aux
->l_prev
->l_next
= args
.aux
->l_next
;
383 if (args
.aux
->l_next
)
384 args
.aux
->l_next
->l_prev
= args
.aux
->l_prev
;
386 args
.aux
->l_prev
= newp
->map
->l_prev
;
387 newp
->map
->l_prev
= args
.aux
;
388 if (args
.aux
->l_prev
!= NULL
)
389 args
.aux
->l_prev
->l_next
= args
.aux
;
390 args
.aux
->l_next
= newp
->map
;
394 /* The object must be somewhere earlier in the
395 list. That's good, we only have to insert
396 an entry for the duplicate list. */
397 orig
->unique
= NULL
; /* Never used. */
399 /* Now we have a problem. The element
400 pointing to ORIG in the unique list must
401 point to NEWP now. This is the only place
402 where we need this backreference and this
403 situation is really not that frequent. So
404 we don't use a double-linked list but
405 instead search for the preceding element. */
407 while (late
->unique
!= orig
)
414 /* This is easy. We just add the symbol right here. */
417 /* Set the mark bit that says it's already in the list. */
418 args
.aux
->l_reserved
= 1;
420 /* The only problem is that in the double linked
421 list of all objects we don't have this new
422 object at the correct place. Correct this here. */
423 if (args
.aux
->l_prev
)
424 args
.aux
->l_prev
->l_next
= args
.aux
->l_next
;
425 if (args
.aux
->l_next
)
426 args
.aux
->l_next
->l_prev
= args
.aux
->l_prev
;
428 args
.aux
->l_prev
= newp
->map
->l_prev
;
429 newp
->map
->l_prev
= args
.aux
;
430 if (args
.aux
->l_prev
!= NULL
)
431 args
.aux
->l_prev
->l_next
= args
.aux
;
432 args
.aux
->l_next
= newp
->map
;
435 /* Move the tail pointers if necessary. */
441 /* Move on the insert point. */
444 /* We always add an entry to the duplicate list. */
449 /* Terminate the list of dependencies and store the array address. */
452 needed
[nneeded
++] = NULL
;
454 l
->l_initfini
= malloc (nneeded
* sizeof needed
[0]);
455 if (l
->l_initfini
== NULL
)
456 _dl_signal_error (ENOMEM
, map
->l_name
,
457 N_("cannot allocate dependency list"));
458 memcpy (l
->l_initfini
, needed
, nneeded
* sizeof needed
[0]);
461 /* If we have no auxiliary objects just go on to the next map. */
465 while (runp
!= NULL
&& runp
->done
);
468 /* Store the search list we built in the object. It will be used for
469 searches in the scope of this object. */
470 map
->l_searchlist
.r_list
= malloc ((2 * nlist
+ 1
471 + (nlist
== nduplist
? 0 : nduplist
))
472 * sizeof (struct link_map
*));
473 if (map
->l_searchlist
.r_list
== NULL
)
474 _dl_signal_error (ENOMEM
, map
->l_name
,
475 N_("cannot allocate symbol search list"));
476 map
->l_searchlist
.r_nlist
= nlist
;
478 for (nlist
= 0, runp
= known
; runp
; runp
= runp
->unique
)
480 if (trace_mode
&& runp
->map
->l_opencount
== 0)
481 /* This can happen when we trace the loading. */
482 --map
->l_searchlist
.r_nlist
;
484 map
->l_searchlist
.r_list
[nlist
++] = runp
->map
;
486 /* Now clear all the mark bits we set in the objects on the search list
487 to avoid duplicates, so the next call starts fresh. */
488 runp
->map
->l_reserved
= 0;
491 map
->l_searchlist
.r_nduplist
= nduplist
;
492 if (nlist
== nduplist
)
493 map
->l_searchlist
.r_duplist
= map
->l_searchlist
.r_list
;
498 map
->l_searchlist
.r_duplist
= map
->l_searchlist
.r_list
+ nlist
;
500 for (cnt
= 0, runp
= known
; runp
; runp
= runp
->dup
)
501 if (trace_mode
&& runp
->map
->l_opencount
== 0)
502 /* This can happen when we trace the loading. */
503 --map
->l_searchlist
.r_nduplist
;
505 map
->l_searchlist
.r_duplist
[cnt
++] = runp
->map
;
508 /* Now determine the order in which the initialization has to happen. */
510 (struct link_map
**) memcpy (map
->l_searchlist
.r_duplist
+ nduplist
,
511 map
->l_searchlist
.r_list
,
512 nlist
* sizeof (struct link_map
*));
513 /* We can skip looking for the binary itself which is at the front
514 of the search list. Look through the list backward so that circular
515 dependencies are not changing the order. */
516 for (i
= 1; i
< nlist
; ++i
)
518 struct link_map
*l
= map
->l_searchlist
.r_list
[i
];
522 /* Find the place in the initfini list where the map is currently
524 for (j
= 1; map
->l_initfini
[j
] != l
; ++j
)
527 /* Find all object for which the current one is a dependency and
528 move the found object (if necessary) in front. */
529 for (k
= j
+ 1; k
< nlist
; ++k
)
531 struct link_map
**runp
;
533 runp
= map
->l_initfini
[k
]->l_initfini
;
536 while (*runp
!= NULL
)
539 struct link_map
*here
= map
->l_initfini
[k
];
542 memmove (&map
->l_initfini
[j
] + 1,
544 (k
- j
) * sizeof (struct link_map
*));
545 map
->l_initfini
[j
] = here
;
554 /* Terminate the list of dependencies. */
555 map
->l_initfini
[nlist
] = NULL
;