1/* Run-time dynamic linker data structures for loaded ELF shared objects.
2 Copyright (C) 1995-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
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.
9
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.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#ifndef _LDSODEFS_H
20#define _LDSODEFS_H 1
21
22#include <features.h>
23
24#include <stdbool.h>
25#define __need_size_t
26#define __need_NULL
27#include <stddef.h>
28#include <string.h>
29#include <stdint.h>
30
31#include <elf.h>
32#include <dlfcn.h>
33#include <fpu_control.h>
34#include <sys/mman.h>
35#include <link.h>
36#include <dl-lookupcfg.h>
37#include <dl-sysdep.h>
38#include <dl-fixup-attribute.h>
39#include <libc-lock.h>
40#include <hp-timing.h>
41#include <tls.h>
42#include <list_t.h>
43
44__BEGIN_DECLS
45
46#define VERSYMIDX(sym) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (sym))
47#define VALIDX(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
48 + DT_EXTRANUM + DT_VALTAGIDX (tag))
49#define ADDRIDX(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
50 + DT_EXTRANUM + DT_VALNUM + DT_ADDRTAGIDX (tag))
51
52/* Type of GNU hash which the machine uses. */
53#ifndef ELF_MACHINE_GNU_HASH_ADDRIDX
54# define ELF_MACHINE_GNU_HASH_ADDRIDX ADDRIDX (DT_GNU_HASH)
55#endif
56
57/* Calculate the index of a symbol in GNU hash. */
58#ifndef ELF_MACHINE_HASH_SYMIDX
59# define ELF_MACHINE_HASH_SYMIDX(map, hasharr) \
60 ((hasharr) - (map)->l_gnu_chain_zero)
61#endif
62
63/* Setup MIPS xhash. Defined only for MIPS. */
64#ifndef ELF_MACHINE_XHASH_SETUP
65# define ELF_MACHINE_XHASH_SETUP(hash32, symbias, map) \
66 ((void) (hash32), (void) (symbias), (void) (map))
67#endif
68
69/* We use this macro to refer to ELF types independent of the native wordsize.
70 `ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'. */
71#define ELFW(type) _ElfW (ELF, __ELF_NATIVE_CLASS, type)
72
73/* Return true if dynamic section in the shared library L should be
74 relocated. */
75
76static inline bool
77dl_relocate_ld (const struct link_map *l)
78{
79 /* Don't relocate dynamic section if it is readonly */
80 return !(l->l_ld_readonly || DL_RO_DYN_SECTION);
81}
82
83/* All references to the value of l_info[DT_PLTGOT],
84 l_info[DT_STRTAB], l_info[DT_SYMTAB], l_info[DT_RELA],
85 l_info[DT_REL], l_info[DT_JMPREL], and l_info[VERSYMIDX (DT_VERSYM)]
86 have to be accessed via the D_PTR macro. The macro is needed since for
87 most architectures the entry is already relocated - but for some not
88 and we need to relocate at access time. */
89#define D_PTR(map, i) \
90 ((map)->i->d_un.d_ptr + (dl_relocate_ld (map) ? 0 : (map)->l_addr))
91
92/* Result of the lookup functions and how to retrieve the base address. */
93typedef struct link_map *lookup_t;
94#define LOOKUP_VALUE(map) map
95#define LOOKUP_VALUE_ADDRESS(map, set) ((set) || (map) ? (map)->l_addr : 0)
96
97/* Calculate the address of symbol REF using the base address from map MAP,
98 if non-NULL. Don't check for NULL map if MAP_SET is TRUE. */
99#define SYMBOL_ADDRESS(map, ref, map_set) \
100 ((ref) == NULL ? 0 \
101 : (__glibc_unlikely ((ref)->st_shndx == SHN_ABS) ? 0 \
102 : LOOKUP_VALUE_ADDRESS (map, map_set)) + (ref)->st_value)
103
104/* Type of a constructor function, in DT_INIT, DT_INIT_ARRAY,
105 DT_PREINIT_ARRAY. */
106typedef void (*dl_init_t) (int, char **, char **);
107
108/* Type of a constructor function, in DT_FINI, DT_FINI_ARRAY. */
109typedef void (*fini_t) (void);
110
111/* On some architectures a pointer to a function is not just a pointer
112 to the actual code of the function but rather an architecture
113 specific descriptor. */
114#ifndef ELF_FUNCTION_PTR_IS_SPECIAL
115# define DL_SYMBOL_ADDRESS(map, ref) \
116 (void *) SYMBOL_ADDRESS (map, ref, false)
117# define DL_LOOKUP_ADDRESS(addr) ((ElfW(Addr)) (addr))
118# define DL_CALL_DT_INIT(map, start, argc, argv, env) \
119 ((dl_init_t) (start)) (argc, argv, env)
120# define DL_CALL_DT_FINI(map, start) ((fini_t) (start)) ()
121#endif
122
123/* On some architectures dladdr can't use st_size of all symbols this way. */
124#define DL_ADDR_SYM_MATCH(L, SYM, MATCHSYM, ADDR) \
125 ((ADDR) >= (L)->l_addr + (SYM)->st_value \
126 && ((((SYM)->st_shndx == SHN_UNDEF || (SYM)->st_size == 0) \
127 && (ADDR) == (L)->l_addr + (SYM)->st_value) \
128 || (ADDR) < (L)->l_addr + (SYM)->st_value + (SYM)->st_size) \
129 && ((MATCHSYM) == NULL || (MATCHSYM)->st_value < (SYM)->st_value))
130
131/* According to the ELF gABI no STV_HIDDEN or STV_INTERNAL symbols are
132 expected to be present in dynamic symbol tables as they should have
133 been either removed or converted to STB_LOCAL binding by the static
134 linker. However some GNU binutils versions produce such symbols in
135 some cases. To prevent such symbols present in a buggy binary from
136 preempting global symbols we filter them out with this predicate. */
137static __always_inline bool
138dl_symbol_visibility_binds_local_p (const ElfW(Sym) *sym)
139{
140 return (ELFW(ST_VISIBILITY) (sym->st_other) == STV_HIDDEN
141 || ELFW(ST_VISIBILITY) (sym->st_other) == STV_INTERNAL);
142}
143
144/* Unmap a loaded object, called by _dl_close (). */
145#ifndef DL_UNMAP_IS_SPECIAL
146# define DL_UNMAP(map) _dl_unmap_segments (map)
147#endif
148
149/* Reloc type classes as returned by elf_machine_type_class().
150 ELF_RTYPE_CLASS_PLT means this reloc should not be satisfied by
151 some PLT symbol, ELF_RTYPE_CLASS_COPY means this reloc should not be
152 satisfied by any symbol in the executable. Some architectures do
153 not support copy relocations. In this case we define the macro to
154 zero so that the code for handling them gets automatically optimized
155 out. ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA means address of protected
156 data defined in the shared library may be external, i.e., due to copy
157 relocation. */
158#define ELF_RTYPE_CLASS_PLT 1
159#ifndef DL_NO_COPY_RELOCS
160# define ELF_RTYPE_CLASS_COPY 2
161#else
162# define ELF_RTYPE_CLASS_COPY 0
163#endif
164/* If DL_EXTERN_PROTECTED_DATA is defined, address of protected data
165 defined in the shared library may be external, i.e., due to copy
166 relocation. */
167#ifdef DL_EXTERN_PROTECTED_DATA
168# define ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA 4
169#else
170# define ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA 0
171#endif
172
173/* ELF uses the PF_x macros to specify the segment permissions, mmap
174 uses PROT_xxx. In most cases the three macros have the values 1, 2,
175 and 3 but not in a matching order. The following macros allows
176 converting from the PF_x values to PROT_xxx values. */
177#define PF_TO_PROT \
178 ((PROT_READ << (PF_R * 4)) \
179 | (PROT_WRITE << (PF_W * 4)) \
180 | (PROT_EXEC << (PF_X * 4)) \
181 | ((PROT_READ | PROT_WRITE) << ((PF_R | PF_W) * 4)) \
182 | ((PROT_READ | PROT_EXEC) << ((PF_R | PF_X) * 4)) \
183 | ((PROT_WRITE | PROT_EXEC) << (PF_W | PF_X) * 4) \
184 | ((PROT_READ | PROT_WRITE | PROT_EXEC) << ((PF_R | PF_W | PF_X) * 4)))
185
186/* The filename itself, or the main program name, if available. */
187#define DSO_FILENAME(name) ((name)[0] ? (name) \
188 : (rtld_progname ?: "<main program>"))
189
190#define RTLD_PROGNAME (rtld_progname ?: "<program name unknown>")
191
192/* For the version handling we need an array with only names and their
193 hash values. */
194struct r_found_version
195 {
196 const char *name;
197 ElfW(Word) hash;
198
199 int hidden;
200 const char *filename;
201 };
202
203/* We want to cache information about the searches for shared objects. */
204
205enum r_dir_status { unknown, nonexisting, existing };
206
207struct r_search_path_elem
208 {
209 /* This link is only used in the `all_dirs' member of `r_search_path'. */
210 struct r_search_path_elem *next;
211
212 /* Strings saying where the definition came from. */
213 const char *what;
214 const char *where;
215
216 /* Basename for this search path element. The string must end with
217 a slash character. */
218 const char *dirname;
219 size_t dirnamelen;
220
221 enum r_dir_status status[0];
222 };
223
224struct r_strlenpair
225 {
226 const char *str;
227 size_t len;
228 };
229
230
231/* A data structure for a simple single linked list of strings. */
232struct libname_list
233 {
234 const char *name; /* Name requested (before search). */
235 struct libname_list *next; /* Link to next name for this object. */
236 int dont_free; /* Flag whether this element should be freed
237 if the object is not entirely unloaded. */
238 };
239
240
241/* Bit masks for the objects which valid callers can come from to
242 functions with restricted interface. */
243enum allowmask
244 {
245 allow_libc = 1,
246 allow_libdl = 2,
247 allow_libpthread = 4,
248 allow_ldso = 8
249 };
250
251
252/* DSO sort algorithm to use (check dl-sort-maps.c). */
253enum dso_sort_algorithm
254 {
255 dso_sort_algorithm_original,
256 dso_sort_algorithm_dfs
257 };
258
259struct audit_ifaces
260{
261 void (*activity) (uintptr_t *, unsigned int);
262 char *(*objsearch) (const char *, uintptr_t *, unsigned int);
263 unsigned int (*objopen) (struct link_map *, Lmid_t, uintptr_t *);
264 void (*preinit) (uintptr_t *);
265 union
266 {
267 uintptr_t (*symbind32) (Elf32_Sym *, unsigned int, uintptr_t *,
268 uintptr_t *, unsigned int *, const char *);
269 uintptr_t (*symbind64) (Elf64_Sym *, unsigned int, uintptr_t *,
270 uintptr_t *, unsigned int *, const char *);
271 };
272 union
273 {
274#ifdef ARCH_PLTENTER_MEMBERS
275 ARCH_PLTENTER_MEMBERS;
276#endif
277 };
278 union
279 {
280#ifdef ARCH_PLTEXIT_MEMBERS
281 ARCH_PLTEXIT_MEMBERS;
282#endif
283 };
284 unsigned int (*objclose) (uintptr_t *);
285
286 struct audit_ifaces *next;
287};
288
289
290/* Test whether given NAME matches any of the names of the given object. */
291extern int _dl_name_match_p (const char *__name, const struct link_map *__map)
292 attribute_hidden;
293
294/* Compute next higher prime number. */
295extern unsigned long int _dl_higher_prime_number (unsigned long int n)
296 attribute_hidden;
297
298/* A stripped down strtoul-like implementation. */
299uint64_t _dl_strtoul (const char *, char **) attribute_hidden;
300
301/* Function used as argument for `_dl_receive_error' function. The
302 arguments are the error code, error string, and the objname the
303 error occurred in. */
304typedef void (*receiver_fct) (int, const char *, const char *);
305
306/* Internal functions of the run-time dynamic linker.
307 These can be accessed if you link again the dynamic linker
308 as a shared library, as in `-lld' or `/lib/ld.so' explicitly;
309 but are not normally of interest to user programs.
310
311 The `-ldl' library functions in <dlfcn.h> provide a simple
312 user interface to run-time dynamic linking. */
313
314
315#ifndef SHARED
316# define EXTERN extern
317# define GL(name) _##name
318#else
319# define EXTERN
320# if IS_IN (rtld)
321# define GL(name) _rtld_local._##name
322# else
323# define GL(name) _rtld_global._##name
324# endif
325struct rtld_global
326{
327#endif
328 /* Don't change the order of the following elements. 'dl_loaded'
329 must remain the first element. Forever. */
330
331/* Non-shared code has no support for multiple namespaces. */
332#ifdef SHARED
333# define DL_NNS 16
334#else
335# define DL_NNS 1
336#endif
337 EXTERN struct link_namespaces
338 {
339 /* A pointer to the map for the main map. */
340 struct link_map *_ns_loaded;
341 /* Number of object in the _dl_loaded list. */
342 unsigned int _ns_nloaded;
343 /* Direct pointer to the searchlist of the main object. */
344 struct r_scope_elem *_ns_main_searchlist;
345 /* This is zero at program start to signal that the global scope map is
346 allocated by rtld. Later it keeps the size of the map. It might be
347 reset if in _dl_close if the last global object is removed. */
348 unsigned int _ns_global_scope_alloc;
349
350 /* During dlopen, this is the number of objects that still need to
351 be added to the global scope map. It has to be taken into
352 account when resizing the map, for future map additions after
353 recursive dlopen calls from ELF constructors. */
354 unsigned int _ns_global_scope_pending_adds;
355
356 /* Once libc.so has been loaded into the namespace, this points to
357 its link map. */
358 struct link_map *libc_map;
359
360 /* Search table for unique objects. */
361 struct unique_sym_table
362 {
363 __rtld_lock_define_recursive (, lock)
364 struct unique_sym
365 {
366 uint32_t hashval;
367 const char *name;
368 const ElfW(Sym) *sym;
369 const struct link_map *map;
370 } *entries;
371 size_t size;
372 size_t n_elements;
373 void (*free) (void *);
374 } _ns_unique_sym_table;
375 /* Keep track of changes to each namespace' list. */
376 struct r_debug_extended _ns_debug;
377 } _dl_ns[DL_NNS];
378 /* One higher than index of last used namespace. */
379 EXTERN size_t _dl_nns;
380
381 /* During the program run we must not modify the global data of
382 loaded shared object simultanously in two threads. Therefore we
383 protect `_dl_open' and `_dl_close' in dl-close.c.
384
385 This must be a recursive lock since the initializer function of
386 the loaded object might as well require a call to this function.
387 At this time it is not anymore a problem to modify the tables. */
388 __rtld_lock_define_recursive (EXTERN, _dl_load_lock)
389 /* This lock is used to keep __dl_iterate_phdr from inspecting the
390 list of loaded objects while an object is added to or removed
391 from that list. */
392 __rtld_lock_define_recursive (EXTERN, _dl_load_write_lock)
393 /* This lock protects global and module specific TLS related data.
394 E.g. it is held in dlopen and dlclose when GL(dl_tls_generation),
395 GL(dl_tls_max_dtv_idx) or GL(dl_tls_dtv_slotinfo_list) are
396 accessed and when TLS related relocations are processed for a
397 module. It was introduced to keep pthread_create accessing TLS
398 state that is being set up. */
399 __rtld_lock_define_recursive (EXTERN, _dl_load_tls_lock)
400
401 /* Incremented whenever something may have been added to dl_loaded. */
402 EXTERN unsigned long long _dl_load_adds;
403
404 /* The object to be initialized first. */
405 EXTERN struct link_map *_dl_initfirst;
406
407 /* Map of shared object to be profiled. */
408 EXTERN struct link_map *_dl_profile_map;
409
410 /* Counters for the number of relocations performed. */
411 EXTERN unsigned long int _dl_num_relocations;
412 EXTERN unsigned long int _dl_num_cache_relocations;
413
414 /* List of search directories. */
415 EXTERN struct r_search_path_elem *_dl_all_dirs;
416
417 /* Structure describing the dynamic linker itself. */
418 EXTERN struct link_map _dl_rtld_map;
419#ifdef SHARED
420 /* Used to store the audit information for the link map of the
421 dynamic loader. */
422 struct auditstate _dl_rtld_auditstate[DL_NNS];
423#endif
424
425#if !PTHREAD_IN_LIBC && defined SHARED \
426 && defined __rtld_lock_default_lock_recursive
427 EXTERN void (*_dl_rtld_lock_recursive) (void *);
428 EXTERN void (*_dl_rtld_unlock_recursive) (void *);
429#endif
430
431 /* Get architecture specific definitions. */
432#define PROCINFO_DECL
433#ifndef PROCINFO_CLASS
434# define PROCINFO_CLASS EXTERN
435#endif
436#include <dl-procruntime.c>
437
438#if !PTHREAD_IN_LIBC
439 /* If loading a shared object requires that we make the stack executable
440 when it was not, we do it by calling this function.
441 It returns an errno code or zero on success. */
442 EXTERN int (*_dl_make_stack_executable_hook) (void **);
443#endif
444
445 /* Prevailing state of the stack, PF_X indicating it's executable. */
446 EXTERN ElfW(Word) _dl_stack_flags;
447
448 /* Flag signalling whether there are gaps in the module ID allocation. */
449 EXTERN bool _dl_tls_dtv_gaps;
450 /* Highest dtv index currently needed. */
451 EXTERN size_t _dl_tls_max_dtv_idx;
452 /* Information about the dtv slots. */
453 EXTERN struct dtv_slotinfo_list
454 {
455 size_t len;
456 struct dtv_slotinfo_list *next;
457 struct dtv_slotinfo
458 {
459 size_t gen;
460 struct link_map *map;
461 } slotinfo[];
462 } *_dl_tls_dtv_slotinfo_list;
463 /* Number of modules in the static TLS block. */
464 EXTERN size_t _dl_tls_static_nelem;
465 /* Size actually allocated in the static TLS block. */
466 EXTERN size_t _dl_tls_static_used;
467 /* Remaining amount of static TLS that may be used for optimizing
468 dynamic TLS access (e.g. with TLSDESC). */
469 EXTERN size_t _dl_tls_static_optional;
470
471/* Number of additional entries in the slotinfo array of each slotinfo
472 list element. A large number makes it almost certain take we never
473 have to iterate beyond the first element in the slotinfo list. */
474#define TLS_SLOTINFO_SURPLUS (62)
475
476/* Number of additional slots in the dtv allocated. */
477#define DTV_SURPLUS (14)
478
479 /* Initial dtv of the main thread, not allocated with normal malloc. */
480 EXTERN void *_dl_initial_dtv;
481 /* Generation counter for the dtv. */
482 EXTERN size_t _dl_tls_generation;
483
484#if !PTHREAD_IN_LIBC
485 EXTERN void (*_dl_init_static_tls) (struct link_map *);
486#endif
487
488 /* Scopes to free after next THREAD_GSCOPE_WAIT (). */
489 EXTERN struct dl_scope_free_list
490 {
491 size_t count;
492 void *list[50];
493 } *_dl_scope_free_list;
494#if PTHREAD_IN_LIBC
495 /* List of active thread stacks, with memory managed by glibc. */
496 EXTERN list_t _dl_stack_used;
497
498 /* List of thread stacks that were allocated by the application. */
499 EXTERN list_t _dl_stack_user;
500
501 /* List of queued thread stacks. */
502 EXTERN list_t _dl_stack_cache;
503
504 /* Total size of all stacks in the cache (sum over stackblock_size). */
505 EXTERN size_t _dl_stack_cache_actsize;
506
507 /* We need to record what list operations we are going to do so
508 that, in case of an asynchronous interruption due to a fork()
509 call, we can correct for the work. */
510 EXTERN uintptr_t _dl_in_flight_stack;
511
512 /* Mutex protecting the stack lists. */
513 EXTERN int _dl_stack_cache_lock;
514#else
515 /* The total number of thread IDs currently in use, or on the list of
516 available thread IDs. */
517 EXTERN int _dl_pthread_num_threads;
518
519 /* Array of __pthread structures and its lock. */
520 EXTERN struct __pthread **_dl_pthread_threads;
521 __libc_rwlock_define (EXTERN, _dl_pthread_threads_lock)
522#endif
523#ifdef SHARED
524};
525# define __rtld_global_attribute__
526# if IS_IN (rtld)
527# ifdef HAVE_SDATA_SECTION
528# define __rtld_local_attribute__ \
529 __attribute__ ((visibility ("hidden"), section (".sdata")))
530# undef __rtld_global_attribute__
531# define __rtld_global_attribute__ __attribute__ ((section (".sdata")))
532# else
533# define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
534# endif
535extern struct rtld_global _rtld_local __rtld_local_attribute__;
536# undef __rtld_local_attribute__
537# endif
538extern struct rtld_global _rtld_global __rtld_global_attribute__;
539# undef __rtld_global_attribute__
540#endif
541
542#ifndef SHARED
543# define GLRO(name) _##name
544#else
545# if IS_IN (rtld)
546# define GLRO(name) _rtld_local_ro._##name
547# else
548# define GLRO(name) _rtld_global_ro._##name
549# endif
550struct rtld_global_ro
551{
552#endif
553
554 /* If nonzero the appropriate debug information is printed. */
555 EXTERN int _dl_debug_mask;
556#define DL_DEBUG_LIBS (1 << 0)
557#define DL_DEBUG_IMPCALLS (1 << 1)
558#define DL_DEBUG_BINDINGS (1 << 2)
559#define DL_DEBUG_SYMBOLS (1 << 3)
560#define DL_DEBUG_VERSIONS (1 << 4)
561#define DL_DEBUG_RELOC (1 << 5)
562#define DL_DEBUG_FILES (1 << 6)
563#define DL_DEBUG_STATISTICS (1 << 7)
564#define DL_DEBUG_UNUSED (1 << 8)
565#define DL_DEBUG_SCOPES (1 << 9)
566/* These two are used only internally. */
567#define DL_DEBUG_HELP (1 << 10)
568#define DL_DEBUG_PRELINK (1 << 11)
569
570 /* OS version. */
571 EXTERN unsigned int _dl_osversion;
572 /* Platform name. */
573 EXTERN const char *_dl_platform;
574 EXTERN size_t _dl_platformlen;
575
576 /* Cached value of `getpagesize ()'. */
577 EXTERN size_t _dl_pagesize;
578
579 /* Cached value of `sysconf (_SC_MINSIGSTKSZ)'. */
580 EXTERN size_t _dl_minsigstacksize;
581
582 /* Do we read from ld.so.cache? */
583 EXTERN int _dl_inhibit_cache;
584
585 /* Copy of the content of `_dl_main_searchlist' at startup time. */
586 EXTERN struct r_scope_elem _dl_initial_searchlist;
587
588 /* CLK_TCK as reported by the kernel. */
589 EXTERN int _dl_clktck;
590
591 /* If nonzero print warnings messages. */
592 EXTERN int _dl_verbose;
593
594 /* File descriptor to write debug messages to. */
595 EXTERN int _dl_debug_fd;
596
597 /* Do we do lazy relocations? */
598 EXTERN int _dl_lazy;
599
600 /* Nonzero if runtime lookups should not update the .got/.plt. */
601 EXTERN int _dl_bind_not;
602
603 /* Nonzero if references should be treated as weak during runtime
604 linking. */
605 EXTERN int _dl_dynamic_weak;
606
607 /* Default floating-point control word. */
608 EXTERN fpu_control_t _dl_fpu_control;
609
610 /* Expected cache ID. */
611 EXTERN int _dl_correct_cache_id;
612
613 /* Mask for hardware capabilities that are available. */
614 EXTERN uint64_t _dl_hwcap;
615
616#if !HAVE_TUNABLES
617 /* Mask for important hardware capabilities we honour. */
618 EXTERN uint64_t _dl_hwcap_mask;
619#endif
620
621#ifdef HAVE_AUX_VECTOR
622 /* Pointer to the auxv list supplied to the program at startup. */
623 EXTERN ElfW(auxv_t) *_dl_auxv;
624#endif
625
626 /* Get architecture specific definitions. */
627#include <dl-procinfo.c>
628
629 /* Names of shared object for which the RPATH should be ignored. */
630 EXTERN const char *_dl_inhibit_rpath;
631
632 /* Location of the binary. */
633 EXTERN const char *_dl_origin_path;
634
635 /* -1 if the dynamic linker should honor library load bias,
636 0 if not, -2 use the default (honor biases for normal
637 binaries, don't honor for PIEs). */
638 EXTERN ElfW(Addr) _dl_use_load_bias;
639
640 /* Size of the static TLS block. */
641 EXTERN size_t _dl_tls_static_size;
642
643 /* Alignment requirement of the static TLS block. */
644 EXTERN size_t _dl_tls_static_align;
645
646 /* Size of surplus space in the static TLS area for dynamically
647 loaded modules with IE-model TLS or for TLSDESC optimization.
648 See comments in elf/dl-tls.c where it is initialized. */
649 EXTERN size_t _dl_tls_static_surplus;
650
651 /* Name of the shared object to be profiled (if any). */
652 EXTERN const char *_dl_profile;
653 /* Filename of the output file. */
654 EXTERN const char *_dl_profile_output;
655 /* Name of the object we want to trace the prelinking. */
656 EXTERN const char *_dl_trace_prelink;
657 /* Map of shared object to be prelink traced. */
658 EXTERN struct link_map *_dl_trace_prelink_map;
659
660 /* All search directories defined at startup. This is assigned a
661 non-NULL pointer by the ld.so startup code (after initialization
662 to NULL), so this can also serve as an indicator whether a copy
663 of ld.so is initialized and active. See the rtld_active function
664 below. */
665 EXTERN struct r_search_path_elem *_dl_init_all_dirs;
666
667#ifdef NEED_DL_SYSINFO
668 /* Syscall handling improvements. This is very specific to x86. */
669 EXTERN uintptr_t _dl_sysinfo;
670#endif
671
672#ifdef NEED_DL_SYSINFO_DSO
673 /* The vsyscall page is a virtual DSO pre-mapped by the kernel.
674 This points to its ELF header. */
675 EXTERN const ElfW(Ehdr) *_dl_sysinfo_dso;
676
677 /* At startup time we set up the normal DSO data structure for it,
678 and this points to it. */
679 EXTERN struct link_map *_dl_sysinfo_map;
680
681# define PROCINFO_DECL
682# ifndef PROCINFO_CLASS
683# define PROCINFO_CLASS EXTERN
684# endif
685# include <dl-vdso-setup.c>
686#endif
687
688 /* Mask for more hardware capabilities that are available on some
689 platforms. */
690 EXTERN uint64_t _dl_hwcap2;
691
692 EXTERN enum dso_sort_algorithm _dl_dso_sort_algo;
693
694#ifdef SHARED
695 /* We add a function table to _rtld_global which is then used to
696 call the function instead of going through the PLT. The result
697 is that we can avoid exporting the functions and we do not jump
698 PLT relocations in libc.so. */
699 void (*_dl_debug_printf) (const char *, ...)
700 __attribute__ ((__format__ (__printf__, 1, 2)));
701 void (*_dl_mcount) (ElfW(Addr) frompc, ElfW(Addr) selfpc);
702 lookup_t (*_dl_lookup_symbol_x) (const char *, struct link_map *,
703 const ElfW(Sym) **, struct r_scope_elem *[],
704 const struct r_found_version *, int, int,
705 struct link_map *);
706 void *(*_dl_open) (const char *file, int mode, const void *caller_dlopen,
707 Lmid_t nsid, int argc, char *argv[], char *env[]);
708 void (*_dl_close) (void *map);
709 /* libdl in a secondary namespace (after dlopen) must use
710 _dl_catch_error from the main namespace, so it has to be
711 exported in some way. */
712 int (*_dl_catch_error) (const char **objname, const char **errstring,
713 bool *mallocedp, void (*operate) (void *),
714 void *args);
715 /* libdl in a secondary namespace must use free from the base
716 namespace. */
717 void (*_dl_error_free) (void *);
718 void *(*_dl_tls_get_addr_soft) (struct link_map *);
719
720 /* Called from __libc_shared to deallocate malloc'ed memory. */
721 void (*_dl_libc_freeres) (void);
722
723 /* Implementation of _dl_find_object. The public entry point is in
724 libc, and this is patched by __rtld_static_init to support static
725 dlopen. */
726 int (*_dl_find_object) (void *, struct dl_find_object *);
727
728#ifdef HAVE_DL_DISCOVER_OSVERSION
729 int (*_dl_discover_osversion) (void);
730#endif
731
732 /* Dynamic linker operations used after static dlopen. */
733 const struct dlfcn_hook *_dl_dlfcn_hook;
734
735 /* List of auditing interfaces. */
736 struct audit_ifaces *_dl_audit;
737 unsigned int _dl_naudit;
738};
739# define __rtld_global_attribute__
740# if IS_IN (rtld)
741# define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
742extern struct rtld_global_ro _rtld_local_ro
743 attribute_relro __rtld_local_attribute__;
744extern struct rtld_global_ro _rtld_global_ro
745 attribute_relro __rtld_global_attribute__;
746# undef __rtld_local_attribute__
747# else
748/* We cheat a bit here. We declare the variable as as const even
749 though it is at startup. */
750extern const struct rtld_global_ro _rtld_global_ro
751 attribute_relro __rtld_global_attribute__;
752# endif
753# undef __rtld_global_attribute__
754#endif
755#undef EXTERN
756
757#ifndef SHARED
758/* dl-support.c defines these and initializes them early on. */
759extern const ElfW(Phdr) *_dl_phdr;
760extern size_t _dl_phnum;
761#endif
762
763#if PTHREAD_IN_LIBC
764/* This function changes the permissions of all stacks (not just those
765 of the main stack). */
766int _dl_make_stacks_executable (void **stack_endp) attribute_hidden;
767#else
768/* This is the initial value of GL(dl_make_stack_executable_hook).
769 A threads library can change it. The ld.so implementation changes
770 the permissions of the main stack only. */
771extern int _dl_make_stack_executable (void **stack_endp);
772rtld_hidden_proto (_dl_make_stack_executable)
773#endif
774
775/* Variable pointing to the end of the stack (or close to it). This value
776 must be constant over the runtime of the application. Some programs
777 might use the variable which results in copy relocations on some
778 platforms. But this does not matter, ld.so can always use the local
779 copy. */
780extern void *__libc_stack_end
781#ifndef LIBC_STACK_END_NOT_RELRO
782 attribute_relro
783#endif
784 ;
785rtld_hidden_proto (__libc_stack_end)
786
787/* Parameters passed to the dynamic linker. */
788extern int _dl_argc attribute_hidden attribute_relro;
789extern char **_dl_argv
790#ifndef DL_ARGV_NOT_RELRO
791 attribute_relro
792#endif
793 ;
794rtld_hidden_proto (_dl_argv)
795#if IS_IN (rtld)
796extern unsigned int _dl_skip_args attribute_hidden
797# ifndef DL_ARGV_NOT_RELRO
798 attribute_relro
799# endif
800 ;
801extern unsigned int _dl_skip_args_internal attribute_hidden
802# ifndef DL_ARGV_NOT_RELRO
803 attribute_relro
804# endif
805 ;
806#endif
807#define rtld_progname _dl_argv[0]
808
809/* Flag set at startup and cleared when the last initializer has run. */
810extern int _dl_starting_up;
811weak_extern (_dl_starting_up)
812rtld_hidden_proto (_dl_starting_up)
813
814/* Random data provided by the kernel. */
815extern void *_dl_random attribute_hidden attribute_relro;
816
817/* Write message on the debug file descriptor. The parameters are
818 interpreted as for a `printf' call. All the lines start with a
819 tag showing the PID. */
820extern void _dl_debug_printf (const char *fmt, ...)
821 __attribute__ ((__format__ (__printf__, 1, 2))) attribute_hidden;
822
823/* Write message on the debug file descriptor. The parameters are
824 interpreted as for a `printf' call. All the lines buf the first
825 start with a tag showing the PID. */
826extern void _dl_debug_printf_c (const char *fmt, ...)
827 __attribute__ ((__format__ (__printf__, 1, 2))) attribute_hidden;
828
829
830/* Write a message on the specified descriptor FD. The parameters are
831 interpreted as for a `printf' call. */
832#if IS_IN (rtld) || !defined (SHARED)
833extern void _dl_dprintf (int fd, const char *fmt, ...)
834 __attribute__ ((__format__ (__printf__, 2, 3)))
835 attribute_hidden;
836#else
837__attribute__ ((always_inline, __format__ (__printf__, 2, 3)))
838static inline void
839_dl_dprintf (int fd, const char *fmt, ...)
840{
841 /* Use local declaration to avoid includign <stdio.h>. */
842 extern int __dprintf(int fd, const char *format, ...) attribute_hidden;
843 __dprintf (fd, fmt, __builtin_va_arg_pack ());
844}
845#endif
846
847/* Write LENGTH bytes at BUFFER to FD, like write. Returns the number
848 of bytes written on success, or a negative error constant on
849 failure. */
850ssize_t _dl_write (int fd, const void *buffer, size_t length)
851 attribute_hidden;
852
853/* Write a message on the specified descriptor standard output. The
854 parameters are interpreted as for a `printf' call. */
855void _dl_printf (const char *fmt, ...)
856 attribute_hidden __attribute__ ((__format__ (__printf__, 1, 2)));
857
858/* Write a message on the specified descriptor standard error. The
859 parameters are interpreted as for a `printf' call. */
860void _dl_error_printf (const char *fmt, ...)
861 attribute_hidden __attribute__ ((__format__ (__printf__, 1, 2)));
862
863/* Write a message on the specified descriptor standard error and exit
864 the program. The parameters are interpreted as for a `printf' call. */
865void _dl_fatal_printf (const char *fmt, ...)
866 __attribute__ ((__format__ (__printf__, 1, 2), __noreturn__));
867rtld_hidden_proto (_dl_fatal_printf)
868
869/* An exception raised by the _dl_signal_error function family and
870 caught by _dl_catch_error function family. Exceptions themselves
871 are copied as part of the raise operation, but the strings are
872 not. */
873struct dl_exception
874{
875 const char *objname;
876 const char *errstring;
877
878 /* This buffer typically stores both objname and errstring
879 above. */
880 char *message_buffer;
881};
882
883/* Creates a new exception. This calls malloc; if allocation fails,
884 dummy values are inserted. OBJECT is the name of the problematical
885 shared object, or null if its a general problem. ERRSTRING is a
886 string describing the specific problem. */
887void _dl_exception_create (struct dl_exception *, const char *object,
888 const char *errstring)
889 __attribute__ ((nonnull (1, 3)));
890rtld_hidden_proto (_dl_exception_create)
891
892/* Used internally to implement dlerror message freeing. See
893 include/dlfcn.h and dlfcn/dlerror.c. */
894void _dl_error_free (void *ptr) attribute_hidden;
895
896/* Like _dl_exception_create, but create errstring from a format
897 string FMT. Currently, only "%s" and "%%" are supported as format
898 directives. */
899void _dl_exception_create_format (struct dl_exception *, const char *objname,
900 const char *fmt, ...)
901 __attribute__ ((nonnull (1, 3), format (printf, 3, 4)));
902rtld_hidden_proto (_dl_exception_create_format)
903
904/* Deallocate the exception, freeing allocated buffers (if
905 possible). */
906void _dl_exception_free (struct dl_exception *)
907 __attribute__ ((nonnull (1)));
908rtld_hidden_proto (_dl_exception_free)
909
910/* This function is called by all the internal dynamic linker
911 functions when they encounter an error. ERRCODE is either an
912 `errno' code or zero; it specifies the return value of
913 _dl_catch_error. OCCASION is included in the error message if the
914 process is terminated immediately. */
915void _dl_signal_exception (int errcode, struct dl_exception *,
916 const char *occasion)
917 __attribute__ ((__noreturn__));
918libc_hidden_proto (_dl_signal_exception)
919
920/* Like _dl_signal_exception, but creates the exception first. */
921extern void _dl_signal_error (int errcode, const char *object,
922 const char *occasion, const char *errstring)
923 __attribute__ ((__noreturn__));
924libc_hidden_proto (_dl_signal_error)
925
926/* Like _dl_signal_exception, but may return when called in the
927 context of _dl_receive_error. This is only used during ld.so
928 bootstrap. In static and profiled builds, this is equivalent to
929 _dl_signal_exception. */
930#if IS_IN (rtld)
931extern void _dl_signal_cexception (int errcode, struct dl_exception *,
932 const char *occasion) attribute_hidden;
933#else
934__attribute__ ((always_inline))
935static inline void
936_dl_signal_cexception (int errcode, struct dl_exception *exception,
937 const char *occasion)
938{
939 _dl_signal_exception (errcode, exception, occasion);
940}
941#endif
942
943/* See _dl_signal_cexception above. */
944#if IS_IN (rtld)
945extern void _dl_signal_cerror (int errcode, const char *object,
946 const char *occasion, const char *errstring)
947 attribute_hidden;
948#else
949__attribute__ ((always_inline))
950static inline void
951_dl_signal_cerror (int errcode, const char *object,
952 const char *occasion, const char *errstring)
953{
954 _dl_signal_error (errcode, object, occasion, errstring);
955}
956#endif
957
958/* Call OPERATE, receiving errors from `dl_signal_cerror'. Unlike
959 `_dl_catch_error' the operation is resumed after the OPERATE
960 function returns.
961 ARGS is passed as argument to OPERATE. */
962extern void _dl_receive_error (receiver_fct fct, void (*operate) (void *),
963 void *args) attribute_hidden;
964
965/* Call OPERATE, catching errors from `_dl_signal_error' and related
966 functions. If there is no error, *ERRSTRING is set to null. If
967 there is an error, *ERRSTRING is set to a string constructed from
968 the strings passed to _dl_signal_error, and the error code passed
969 is the return value and *OBJNAME is set to the object name which
970 experienced the problems. ERRSTRING if nonzero points to a
971 malloc'ed string which the caller has to free after use. ARGS is
972 passed as argument to OPERATE. MALLOCEDP is set to true only if
973 the returned string is allocated using the libc's malloc. */
974extern int _dl_catch_error (const char **objname, const char **errstring,
975 bool *mallocedp, void (*operate) (void *),
976 void *args);
977libc_hidden_proto (_dl_catch_error)
978
979/* Used for initializing GLRO (_dl_catch_error). */
980extern __typeof__ (_dl_catch_error) _rtld_catch_error attribute_hidden;
981
982/* Call OPERATE (ARGS). If no error occurs, set *EXCEPTION to zero.
983 Otherwise, store a copy of the raised exception in *EXCEPTION,
984 which has to be freed by _dl_exception_free. As a special case, if
985 EXCEPTION is null, call OPERATE (ARGS) with exception handling
986 disabled (so that exceptions are fatal). */
987int _dl_catch_exception (struct dl_exception *exception,
988 void (*operate) (void *), void *args);
989libc_hidden_proto (_dl_catch_exception)
990
991/* Open the shared object NAME and map in its segments.
992 LOADER's DT_RPATH is used in searching for NAME.
993 If the object is already opened, returns its existing map. */
994extern struct link_map *_dl_map_object (struct link_map *loader,
995 const char *name,
996 int type, int trace_mode, int mode,
997 Lmid_t nsid) attribute_hidden;
998
999/* Call _dl_map_object on the dependencies of MAP, and set up
1000 MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously
1001 loaded objects that will be inserted into MAP->l_searchlist after MAP
1002 but before its dependencies. */
1003extern void _dl_map_object_deps (struct link_map *map,
1004 struct link_map **preloads,
1005 unsigned int npreloads, int trace_mode,
1006 int open_mode)
1007 attribute_hidden;
1008
1009/* Cache the locations of MAP's hash table. */
1010extern void _dl_setup_hash (struct link_map *map) attribute_hidden;
1011
1012
1013/* Collect the directories in the search path for LOADER's dependencies.
1014 The data structure is defined in <dlfcn.h>. If COUNTING is true,
1015 SI->dls_cnt and SI->dls_size are set; if false, those must be as set
1016 by a previous call with COUNTING set, and SI must point to SI->dls_size
1017 bytes to be used in filling in the result. */
1018extern void _dl_rtld_di_serinfo (struct link_map *loader,
1019 Dl_serinfo *si, bool counting);
1020
1021/* Process PT_GNU_PROPERTY program header PH in module L after
1022 PT_LOAD segments are mapped from file FD. */
1023void _dl_process_pt_gnu_property (struct link_map *l, int fd,
1024 const ElfW(Phdr) *ph);
1025
1026
1027/* Search loaded objects' symbol tables for a definition of the symbol
1028 referred to by UNDEF. *SYM is the symbol table entry containing the
1029 reference; it is replaced with the defining symbol, and the base load
1030 address of the defining object is returned. SYMBOL_SCOPE is a
1031 null-terminated list of object scopes to search; each object's
1032 l_searchlist (i.e. the segment of the dependency tree starting at that
1033 object) is searched in turn. REFERENCE_NAME should name the object
1034 containing the reference; it is used in error messages.
1035 TYPE_CLASS describes the type of symbol we are looking for. */
1036enum
1037 {
1038 /* If necessary add dependency between user and provider object. */
1039 DL_LOOKUP_ADD_DEPENDENCY = 1,
1040 /* Return most recent version instead of default version for
1041 unversioned lookup. */
1042 DL_LOOKUP_RETURN_NEWEST = 2,
1043 /* Set if dl_lookup* called with GSCOPE lock held. */
1044 DL_LOOKUP_GSCOPE_LOCK = 4,
1045 /* Set if dl_lookup is called for non-lazy relocation processing
1046 from _dl_relocate_object in elf/dl-reloc.c. */
1047 DL_LOOKUP_FOR_RELOCATE = 8,
1048 };
1049
1050/* Lookup versioned symbol. */
1051extern lookup_t _dl_lookup_symbol_x (const char *undef,
1052 struct link_map *undef_map,
1053 const ElfW(Sym) **sym,
1054 struct r_scope_elem *symbol_scope[],
1055 const struct r_found_version *version,
1056 int type_class, int flags,
1057 struct link_map *skip_map)
1058 attribute_hidden;
1059
1060
1061/* Restricted version of _dl_lookup_symbol_x. Searches MAP (and only
1062 MAP) for the symbol UNDEF_NAME, with GNU hash NEW_HASH (computed
1063 with dl_new_hash), symbol version VERSION, and symbol version hash
1064 VERSION_HASH (computed with _dl_elf_hash). Returns a pointer to
1065 the symbol table entry in MAP on success, or NULL on failure. MAP
1066 must have symbol versioning information, or otherwise the result is
1067 undefined. */
1068const ElfW(Sym) *_dl_lookup_direct (struct link_map *map,
1069 const char *undef_name,
1070 uint32_t new_hash,
1071 const char *version,
1072 uint32_t version_hash) attribute_hidden;
1073
1074/* Add the new link_map NEW to the end of the namespace list. */
1075extern void _dl_add_to_namespace_list (struct link_map *new, Lmid_t nsid)
1076 attribute_hidden;
1077
1078/* Allocate a `struct link_map' for a new object being loaded. */
1079extern struct link_map *_dl_new_object (char *realname, const char *libname,
1080 int type, struct link_map *loader,
1081 int mode, Lmid_t nsid)
1082 attribute_hidden;
1083
1084/* Relocate the given object (if it hasn't already been).
1085 SCOPE is passed to _dl_lookup_symbol in symbol lookups.
1086 If RTLD_LAZY is set in RELOC-MODE, don't relocate its PLT. */
1087extern void _dl_relocate_object (struct link_map *map,
1088 struct r_scope_elem *scope[],
1089 int reloc_mode, int consider_profiling)
1090 attribute_hidden;
1091
1092/* Protect PT_GNU_RELRO area. */
1093extern void _dl_protect_relro (struct link_map *map) attribute_hidden;
1094
1095/* Call _dl_signal_error with a message about an unhandled reloc type.
1096 TYPE is the result of ELFW(R_TYPE) (r_info), i.e. an R_<CPU>_* value.
1097 PLT is nonzero if this was a PLT reloc; it just affects the message. */
1098extern void _dl_reloc_bad_type (struct link_map *map,
1099 unsigned int type, int plt)
1100 attribute_hidden __attribute__ ((__noreturn__));
1101
1102/* Resolve conflicts if prelinking. */
1103extern void _dl_resolve_conflicts (struct link_map *l,
1104 ElfW(Rela) *conflict,
1105 ElfW(Rela) *conflictend)
1106 attribute_hidden;
1107
1108/* Check the version dependencies of all objects available through
1109 MAP. If VERBOSE print some more diagnostics. */
1110extern int _dl_check_all_versions (struct link_map *map, int verbose,
1111 int trace_mode) attribute_hidden;
1112
1113/* Check the version dependencies for MAP. If VERBOSE print some more
1114 diagnostics. */
1115extern int _dl_check_map_versions (struct link_map *map, int verbose,
1116 int trace_mode) attribute_hidden;
1117
1118/* Initialize the object in SCOPE by calling the constructors with
1119 ARGC, ARGV, and ENV as the parameters. */
1120extern void _dl_init (struct link_map *main_map, int argc, char **argv,
1121 char **env) attribute_hidden;
1122
1123/* Call the finalizer functions of all shared objects whose
1124 initializer functions have completed. */
1125extern void _dl_fini (void) attribute_hidden;
1126
1127/* Invoke the DT_FINI_ARRAY and DT_FINI destructors for MAP, which
1128 must be a struct link_map *. Can be used as an argument to
1129 _dl_catch_exception. */
1130void _dl_call_fini (void *map) attribute_hidden;
1131
1132/* Sort array MAPS according to dependencies of the contained objects.
1133 If FORCE_FIRST, MAPS[0] keeps its place even if the dependencies
1134 say otherwise. */
1135extern void _dl_sort_maps (struct link_map **maps, unsigned int nmaps,
1136 bool force_first, bool for_fini) attribute_hidden;
1137
1138/* The dynamic linker calls this function before and having changing
1139 any shared object mappings. The `r_state' member of `struct r_debug'
1140 says what change is taking place. This function's address is
1141 the value of the `r_brk' member. */
1142extern void _dl_debug_state (void);
1143rtld_hidden_proto (_dl_debug_state)
1144
1145/* Initialize `struct r_debug_extended' for the namespace NS. LDBASE
1146 is the run-time load address of the dynamic linker, to be put in the
1147 `r_ldbase' member. Return the address of the structure. */
1148extern struct r_debug *_dl_debug_initialize (ElfW(Addr) ldbase, Lmid_t ns)
1149 attribute_hidden;
1150
1151/* Update the `r_map' member and return the address of `struct r_debug'
1152 of the namespace NS. */
1153extern struct r_debug *_dl_debug_update (Lmid_t ns) attribute_hidden;
1154
1155/* Initialize the basic data structure for the search paths. SOURCE
1156 is either "LD_LIBRARY_PATH" or "--library-path".
1157 GLIBC_HWCAPS_PREPEND adds additional glibc-hwcaps subdirectories to
1158 search. GLIBC_HWCAPS_MASK is used to filter the built-in
1159 subdirectories if not NULL. */
1160extern void _dl_init_paths (const char *library_path, const char *source,
1161 const char *glibc_hwcaps_prepend,
1162 const char *glibc_hwcaps_mask)
1163 attribute_hidden;
1164
1165/* Gather the information needed to install the profiling tables and start
1166 the timers. */
1167extern void _dl_start_profile (void) attribute_hidden;
1168
1169/* The actual functions used to keep book on the calls. */
1170extern void _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc);
1171rtld_hidden_proto (_dl_mcount)
1172
1173/* This function is simply a wrapper around the _dl_mcount function
1174 which does not require a FROMPC parameter since this is the
1175 calling function. */
1176extern void _dl_mcount_wrapper (void *selfpc);
1177
1178/* Show the members of the auxiliary array passed up from the kernel. */
1179extern void _dl_show_auxv (void) attribute_hidden;
1180
1181/* Return all environment variables starting with `LD_', one after the
1182 other. */
1183extern char *_dl_next_ld_env_entry (char ***position) attribute_hidden;
1184
1185/* Return an array with the names of the important hardware
1186 capabilities. PREPEND is a colon-separated list of glibc-hwcaps
1187 directories to search first. MASK is a colon-separated list used
1188 to filter the built-in glibc-hwcaps subdirectories. The length of
1189 the array is written to *SZ, and the maximum of all strings length
1190 is written to *MAX_CAPSTRLEN. */
1191const struct r_strlenpair *_dl_important_hwcaps (const char *prepend,
1192 const char *mask,
1193 size_t *sz,
1194 size_t *max_capstrlen)
1195 attribute_hidden;
1196
1197/* Look up NAME in ld.so.cache and return the file name stored there,
1198 or null if none is found. Caller must free returned string. */
1199extern char *_dl_load_cache_lookup (const char *name) attribute_hidden;
1200
1201/* If the system does not support MAP_COPY we cannot leave the file open
1202 all the time since this would create problems when the file is replaced.
1203 Therefore we provide this function to close the file and open it again
1204 once needed. */
1205extern void _dl_unload_cache (void) attribute_hidden;
1206
1207/* System-dependent function to read a file's whole contents in the
1208 most convenient manner available. *SIZEP gets the size of the
1209 file. On error MAP_FAILED is returned. */
1210extern void *_dl_sysdep_read_whole_file (const char *file, size_t *sizep,
1211 int prot) attribute_hidden;
1212
1213/* System-specific function to do initial startup for the dynamic linker.
1214 After this, file access calls and getenv must work. This is responsible
1215 for setting __libc_enable_secure if we need to be secure (e.g. setuid),
1216 and for setting _dl_argc and _dl_argv, and then calling _dl_main. */
1217extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
1218 void (*dl_main) (const ElfW(Phdr) *phdr,
1219 ElfW(Word) phnum,
1220 ElfW(Addr) *user_entry,
1221 ElfW(auxv_t) *auxv))
1222 attribute_hidden;
1223
1224extern void _dl_sysdep_start_cleanup (void) attribute_hidden;
1225
1226
1227/* Determine next available module ID and set the L l_tls_modid. */
1228extern void _dl_assign_tls_modid (struct link_map *l) attribute_hidden;
1229
1230/* Count the modules with TLS segments. */
1231extern size_t _dl_count_modids (void) attribute_hidden;
1232
1233/* Calculate offset of the TLS blocks in the static TLS block. */
1234extern void _dl_determine_tlsoffset (void) attribute_hidden;
1235
1236/* Calculate the size of the static TLS surplus, when the given
1237 number of audit modules are loaded. */
1238void _dl_tls_static_surplus_init (size_t naudit) attribute_hidden;
1239
1240/* This function is called very early from dl_main to set up TLS and
1241 other thread-related data structures. */
1242void __tls_pre_init_tp (void) attribute_hidden;
1243
1244/* This function is called after processor-specific initialization of
1245 the TCB and thread pointer via TLS_INIT_TP, to complete very early
1246 initialization of the thread library. */
1247void __tls_init_tp (void) attribute_hidden;
1248
1249#ifndef SHARED
1250/* Set up the TCB for statically linked applications. This is called
1251 early during startup because we always use TLS (for errno and the
1252 stack protector, among other things). */
1253void __libc_setup_tls (void);
1254
1255# if ENABLE_STATIC_PIE
1256/* Relocate static executable with PIE. */
1257extern void _dl_relocate_static_pie (void) attribute_hidden;
1258
1259/* Get a pointer to _dl_main_map. */
1260extern struct link_map * _dl_get_dl_main_map (void)
1261 __attribute__ ((visibility ("hidden")));
1262# else
1263# define _dl_relocate_static_pie()
1264# endif
1265#endif
1266
1267/* Perform early memory allocation, avoding a TCB dependency.
1268 Terminate the process if allocation fails. May attempt to use
1269 brk. */
1270void *_dl_early_allocate (size_t size) attribute_hidden;
1271
1272/* Initialize the DSO sort algorithm to use. */
1273#if !HAVE_TUNABLES
1274static inline void
1275__always_inline
1276_dl_sort_maps_init (void)
1277{
1278 /* This is optimized out if tunables are not enabled. */
1279}
1280#else
1281extern void _dl_sort_maps_init (void) attribute_hidden;
1282#endif
1283
1284/* Initialization of libpthread for statically linked applications.
1285 If libpthread is not linked in, this is an empty function. */
1286void __pthread_initialize_minimal (void) weak_function;
1287
1288/* Allocate memory for static TLS block (unless MEM is nonzero) and dtv. */
1289extern void *_dl_allocate_tls (void *mem);
1290rtld_hidden_proto (_dl_allocate_tls)
1291
1292/* Get size and alignment requirements of the static TLS block. */
1293extern void _dl_get_tls_static_info (size_t *sizep, size_t *alignp);
1294
1295extern void _dl_allocate_static_tls (struct link_map *map) attribute_hidden;
1296
1297/* These are internal entry points to the two halves of _dl_allocate_tls,
1298 only used within rtld.c itself at startup time. */
1299extern void *_dl_allocate_tls_storage (void) attribute_hidden;
1300extern void *_dl_allocate_tls_init (void *, bool);
1301rtld_hidden_proto (_dl_allocate_tls_init)
1302
1303/* Deallocate memory allocated with _dl_allocate_tls. */
1304extern void _dl_deallocate_tls (void *tcb, bool dealloc_tcb);
1305rtld_hidden_proto (_dl_deallocate_tls)
1306
1307extern void _dl_nothread_init_static_tls (struct link_map *) attribute_hidden;
1308
1309/* Find origin of the executable. */
1310extern const char *_dl_get_origin (void) attribute_hidden;
1311
1312/* Count DSTs. */
1313extern size_t _dl_dst_count (const char *name) attribute_hidden;
1314
1315/* Substitute DST values. */
1316extern char *_dl_dst_substitute (struct link_map *l, const char *name,
1317 char *result) attribute_hidden;
1318
1319/* Open the shared object NAME, relocate it, and run its initializer if it
1320 hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If
1321 the object is already opened, returns its existing map. */
1322extern void *_dl_open (const char *name, int mode, const void *caller,
1323 Lmid_t nsid, int argc, char *argv[], char *env[])
1324 attribute_hidden;
1325
1326/* Free or queue for freeing scope OLD. If other threads might be
1327 in the middle of _dl_fixup, _dl_profile_fixup or dl*sym using the
1328 old scope, OLD can't be freed until no thread is using it. */
1329extern int _dl_scope_free (void *) attribute_hidden;
1330
1331
1332/* Add module to slot information data. If DO_ADD is false, only the
1333 required memory is allocated. Must be called with GL
1334 (dl_load_tls_lock) acquired. If the function has already been called
1335 for the link map L with !do_add, then this function will not raise
1336 an exception, otherwise it is possible that it encounters a memory
1337 allocation failure. */
1338extern void _dl_add_to_slotinfo (struct link_map *l, bool do_add)
1339 attribute_hidden;
1340
1341/* Update slot information data for at least the generation of the
1342 module with the given index. */
1343extern struct link_map *_dl_update_slotinfo (unsigned long int req_modid)
1344 attribute_hidden;
1345
1346/* Look up the module's TLS block as for __tls_get_addr,
1347 but never touch anything. Return null if it's not allocated yet. */
1348extern void *_dl_tls_get_addr_soft (struct link_map *l) attribute_hidden;
1349
1350extern int _dl_addr_inside_object (struct link_map *l, const ElfW(Addr) addr)
1351 attribute_hidden;
1352
1353/* Show show of an object. */
1354extern void _dl_show_scope (struct link_map *new, int from)
1355 attribute_hidden;
1356
1357extern struct link_map *_dl_find_dso_for_object (const ElfW(Addr) addr);
1358rtld_hidden_proto (_dl_find_dso_for_object)
1359
1360/* Initialization which is normally done by the dynamic linker. */
1361extern void _dl_non_dynamic_init (void)
1362 attribute_hidden;
1363
1364/* Used by static binaries to check the auxiliary vector. */
1365extern void _dl_aux_init (ElfW(auxv_t) *av)
1366 attribute_hidden;
1367
1368/* Initialize the static TLS space for the link map in all existing
1369 threads. */
1370#if PTHREAD_IN_LIBC
1371void _dl_init_static_tls (struct link_map *map) attribute_hidden;
1372#endif
1373static inline void
1374dl_init_static_tls (struct link_map *map)
1375{
1376#if PTHREAD_IN_LIBC
1377 /* The stack list is available to ld.so, so the initialization can
1378 be handled within ld.so directly. */
1379 _dl_init_static_tls (map);
1380#else
1381 GL (dl_init_static_tls) (map);
1382#endif
1383}
1384
1385#ifndef SHARED
1386/* Called before relocating ld.so during static dlopen. This can be
1387 used to partly initialize the dormant ld.so copy in the static
1388 dlopen namespace. */
1389void __rtld_static_init (struct link_map *map) attribute_hidden;
1390#endif
1391
1392/* Return true if the ld.so copy in this namespace is actually active
1393 and working. If false, the dl_open/dlfcn hooks have to be used to
1394 call into the outer dynamic linker (which happens after static
1395 dlopen). */
1396#ifdef SHARED
1397static inline bool
1398rtld_active (void)
1399{
1400 /* The default-initialized variable does not have a non-zero
1401 dl_init_all_dirs member, so this allows us to recognize an
1402 initialized and active ld.so copy. */
1403 return GLRO(dl_init_all_dirs) != NULL;
1404}
1405
1406static inline struct auditstate *
1407link_map_audit_state (struct link_map *l, size_t index)
1408{
1409 if (l == &GL (dl_rtld_map))
1410 /* The auditstate array is stored separately. */
1411 return &GL (dl_rtld_auditstate) [index];
1412 else
1413 {
1414 /* The auditstate array follows the link map in memory. */
1415 struct auditstate *base = (struct auditstate *) (l + 1);
1416 return &base[index];
1417 }
1418}
1419
1420/* Call the la_objsearch from the audit modules from the link map L. If
1421 ORIGNAME is non NULL, it is updated with the revious name prior calling
1422 la_objsearch. */
1423const char *_dl_audit_objsearch (const char *name, struct link_map *l,
1424 unsigned int code)
1425 attribute_hidden;
1426
1427/* Call the la_activity from the audit modules from the link map L and issues
1428 the ACTION argument. */
1429void _dl_audit_activity_map (struct link_map *l, int action)
1430 attribute_hidden;
1431
1432/* Call the la_activity from the audit modules from the link map from the
1433 namespace NSID and issues the ACTION argument. */
1434void _dl_audit_activity_nsid (Lmid_t nsid, int action)
1435 attribute_hidden;
1436
1437/* Call the la_objopen from the audit modules for the link_map L on the
1438 namespace identification NSID. */
1439void _dl_audit_objopen (struct link_map *l, Lmid_t nsid)
1440 attribute_hidden;
1441
1442/* Call the la_objclose from the audit modules for the link_map L. */
1443void _dl_audit_objclose (struct link_map *l)
1444 attribute_hidden;
1445
1446/* Call the la_preinit from the audit modules for the link_map L. */
1447void _dl_audit_preinit (struct link_map *l);
1448
1449/* Call the la_symbind{32,64} from the audit modules for the link_map L. If
1450 RELOC_RESULT is NULL it assumes the symbol to be bind-now and will set
1451 the flags with LA_SYMB_NOPLTENTER | LA_SYMB_NOPLTEXIT prior calling
1452 la_symbind{32,64}. */
1453void _dl_audit_symbind (struct link_map *l, struct reloc_result *reloc_result,
1454 const ElfW(Sym) *defsym, DL_FIXUP_VALUE_TYPE *value,
1455 lookup_t result)
1456 attribute_hidden;
1457/* Same as _dl_audit_symbind, but also sets LA_SYMB_DLSYM flag. */
1458void _dl_audit_symbind_alt (struct link_map *l, const ElfW(Sym) *ref,
1459 void **value, lookup_t result);
1460rtld_hidden_proto (_dl_audit_symbind_alt)
1461void _dl_audit_pltenter (struct link_map *l, struct reloc_result *reloc_result,
1462 DL_FIXUP_VALUE_TYPE *value, void *regs,
1463 long int *framesize)
1464 attribute_hidden;
1465void DL_ARCH_FIXUP_ATTRIBUTE _dl_audit_pltexit (struct link_map *l,
1466 ElfW(Word) reloc_arg,
1467 const void *inregs,
1468 void *outregs)
1469 attribute_hidden;
1470#endif /* SHARED */
1471
1472#if PTHREAD_IN_LIBC && defined SHARED
1473/* Recursive locking implementation for use within the dynamic loader.
1474 Used to define the __rtld_lock_lock_recursive and
1475 __rtld_lock_unlock_recursive via <libc-lock.h>. Initialized to a
1476 no-op dummy implementation early. Similar
1477 to GL (dl_rtld_lock_recursive) and GL (dl_rtld_unlock_recursive)
1478 in !PTHREAD_IN_LIBC builds. */
1479extern int (*___rtld_mutex_lock) (pthread_mutex_t *) attribute_hidden;
1480extern int (*___rtld_mutex_unlock) (pthread_mutex_t *lock) attribute_hidden;
1481
1482/* Called after libc has been loaded, but before RELRO is activated.
1483 Used to initialize the function pointers to the actual
1484 implementations. */
1485void __rtld_mutex_init (void) attribute_hidden;
1486#else /* !PTHREAD_IN_LIBC */
1487static inline void
1488__rtld_mutex_init (void)
1489{
1490 /* The initialization happens later (!PTHREAD_IN_LIBC) or is not
1491 needed at all (!SHARED). */
1492}
1493#endif /* !PTHREAD_IN_LIBC */
1494
1495/* Implementation of GL (dl_libc_freeres). */
1496void __rtld_libc_freeres (void) attribute_hidden;
1497
1498void __thread_gscope_wait (void) attribute_hidden;
1499# define THREAD_GSCOPE_WAIT() __thread_gscope_wait ()
1500
1501__END_DECLS
1502
1503#endif /* ldsodefs.h */
1504

source code of glibc/sysdeps/generic/ldsodefs.h