1/* Run-time dynamic linker data structures for loaded ELF shared objects.
2 Copyright (C) 1995-2019 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 <http://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 <libc-lock.h>
39#include <hp-timing.h>
40#include <tls.h>
41
42__BEGIN_DECLS
43
44#define VERSYMIDX(sym) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (sym))
45#define VALIDX(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
46 + DT_EXTRANUM + DT_VALTAGIDX (tag))
47#define ADDRIDX(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
48 + DT_EXTRANUM + DT_VALNUM + DT_ADDRTAGIDX (tag))
49
50/* We use this macro to refer to ELF types independent of the native wordsize.
51 `ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'. */
52#define ELFW(type) _ElfW (ELF, __ELF_NATIVE_CLASS, type)
53
54/* All references to the value of l_info[DT_PLTGOT],
55 l_info[DT_STRTAB], l_info[DT_SYMTAB], l_info[DT_RELA],
56 l_info[DT_REL], l_info[DT_JMPREL], and l_info[VERSYMIDX (DT_VERSYM)]
57 have to be accessed via the D_PTR macro. The macro is needed since for
58 most architectures the entry is already relocated - but for some not
59 and we need to relocate at access time. */
60#ifdef DL_RO_DYN_SECTION
61# define D_PTR(map, i) ((map)->i->d_un.d_ptr + (map)->l_addr)
62#else
63# define D_PTR(map, i) (map)->i->d_un.d_ptr
64#endif
65
66/* Result of the lookup functions and how to retrieve the base address. */
67typedef struct link_map *lookup_t;
68#define LOOKUP_VALUE(map) map
69#define LOOKUP_VALUE_ADDRESS(map, set) ((set) || (map) ? (map)->l_addr : 0)
70
71/* Calculate the address of symbol REF using the base address from map MAP,
72 if non-NULL. Don't check for NULL map if MAP_SET is TRUE. */
73#define SYMBOL_ADDRESS(map, ref, map_set) \
74 ((ref) == NULL ? 0 \
75 : (__glibc_unlikely ((ref)->st_shndx == SHN_ABS) ? 0 \
76 : LOOKUP_VALUE_ADDRESS (map, map_set)) + (ref)->st_value)
77
78/* On some architectures a pointer to a function is not just a pointer
79 to the actual code of the function but rather an architecture
80 specific descriptor. */
81#ifndef ELF_FUNCTION_PTR_IS_SPECIAL
82# define DL_SYMBOL_ADDRESS(map, ref) \
83 (void *) SYMBOL_ADDRESS (map, ref, false)
84# define DL_LOOKUP_ADDRESS(addr) ((ElfW(Addr)) (addr))
85# define DL_CALL_DT_INIT(map, start, argc, argv, env) \
86 ((init_t) (start)) (argc, argv, env)
87# define DL_CALL_DT_FINI(map, start) ((fini_t) (start)) ()
88#endif
89
90/* On some architectures dladdr can't use st_size of all symbols this way. */
91#define DL_ADDR_SYM_MATCH(L, SYM, MATCHSYM, ADDR) \
92 ((ADDR) >= (L)->l_addr + (SYM)->st_value \
93 && ((((SYM)->st_shndx == SHN_UNDEF || (SYM)->st_size == 0) \
94 && (ADDR) == (L)->l_addr + (SYM)->st_value) \
95 || (ADDR) < (L)->l_addr + (SYM)->st_value + (SYM)->st_size) \
96 && ((MATCHSYM) == NULL || (MATCHSYM)->st_value < (SYM)->st_value))
97
98/* According to the ELF gABI no STV_HIDDEN or STV_INTERNAL symbols are
99 expected to be present in dynamic symbol tables as they should have
100 been either removed or converted to STB_LOCAL binding by the static
101 linker. However some GNU binutils versions produce such symbols in
102 some cases. To prevent such symbols present in a buggy binary from
103 preempting global symbols we filter them out with this predicate. */
104static __always_inline bool
105dl_symbol_visibility_binds_local_p (const ElfW(Sym) *sym)
106{
107 return (ELFW(ST_VISIBILITY) (sym->st_other) == STV_HIDDEN
108 || ELFW(ST_VISIBILITY) (sym->st_other) == STV_INTERNAL);
109}
110
111/* Unmap a loaded object, called by _dl_close (). */
112#ifndef DL_UNMAP_IS_SPECIAL
113# define DL_UNMAP(map) _dl_unmap_segments (map)
114#endif
115
116/* By default we do not need special support to initialize DSOs loaded
117 by statically linked binaries. */
118#ifndef DL_STATIC_INIT
119# define DL_STATIC_INIT(map)
120#endif
121
122/* Reloc type classes as returned by elf_machine_type_class().
123 ELF_RTYPE_CLASS_PLT means this reloc should not be satisfied by
124 some PLT symbol, ELF_RTYPE_CLASS_COPY means this reloc should not be
125 satisfied by any symbol in the executable. Some architectures do
126 not support copy relocations. In this case we define the macro to
127 zero so that the code for handling them gets automatically optimized
128 out. ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA means address of protected
129 data defined in the shared library may be external, i.e., due to copy
130 relocation. */
131#define ELF_RTYPE_CLASS_PLT 1
132#ifndef DL_NO_COPY_RELOCS
133# define ELF_RTYPE_CLASS_COPY 2
134#else
135# define ELF_RTYPE_CLASS_COPY 0
136#endif
137/* If DL_EXTERN_PROTECTED_DATA is defined, address of protected data
138 defined in the shared library may be external, i.e., due to copy
139 relocation. */
140#ifdef DL_EXTERN_PROTECTED_DATA
141# define ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA 4
142#else
143# define ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA 0
144#endif
145
146/* ELF uses the PF_x macros to specify the segment permissions, mmap
147 uses PROT_xxx. In most cases the three macros have the values 1, 2,
148 and 3 but not in a matching order. The following macros allows
149 converting from the PF_x values to PROT_xxx values. */
150#define PF_TO_PROT \
151 ((PROT_READ << (PF_R * 4)) \
152 | (PROT_WRITE << (PF_W * 4)) \
153 | (PROT_EXEC << (PF_X * 4)) \
154 | ((PROT_READ | PROT_WRITE) << ((PF_R | PF_W) * 4)) \
155 | ((PROT_READ | PROT_EXEC) << ((PF_R | PF_X) * 4)) \
156 | ((PROT_WRITE | PROT_EXEC) << (PF_W | PF_X) * 4) \
157 | ((PROT_READ | PROT_WRITE | PROT_EXEC) << ((PF_R | PF_W | PF_X) * 4)))
158
159/* The filename itself, or the main program name, if available. */
160#define DSO_FILENAME(name) ((name)[0] ? (name) \
161 : (rtld_progname ?: "<main program>"))
162
163#define RTLD_PROGNAME (rtld_progname ?: "<program name unknown>")
164
165/* For the version handling we need an array with only names and their
166 hash values. */
167struct r_found_version
168 {
169 const char *name;
170 ElfW(Word) hash;
171
172 int hidden;
173 const char *filename;
174 };
175
176/* We want to cache information about the searches for shared objects. */
177
178enum r_dir_status { unknown, nonexisting, existing };
179
180struct r_search_path_elem
181 {
182 /* This link is only used in the `all_dirs' member of `r_search_path'. */
183 struct r_search_path_elem *next;
184
185 /* Strings saying where the definition came from. */
186 const char *what;
187 const char *where;
188
189 /* Basename for this search path element. The string must end with
190 a slash character. */
191 const char *dirname;
192 size_t dirnamelen;
193
194 enum r_dir_status status[0];
195 };
196
197struct r_strlenpair
198 {
199 const char *str;
200 size_t len;
201 };
202
203
204/* A data structure for a simple single linked list of strings. */
205struct libname_list
206 {
207 const char *name; /* Name requested (before search). */
208 struct libname_list *next; /* Link to next name for this object. */
209 int dont_free; /* Flag whether this element should be freed
210 if the object is not entirely unloaded. */
211 };
212
213
214/* Bit masks for the objects which valid callers can come from to
215 functions with restricted interface. */
216enum allowmask
217 {
218 allow_libc = 1,
219 allow_libdl = 2,
220 allow_libpthread = 4,
221 allow_ldso = 8
222 };
223
224
225struct audit_ifaces
226{
227 void (*activity) (uintptr_t *, unsigned int);
228 char *(*objsearch) (const char *, uintptr_t *, unsigned int);
229 unsigned int (*objopen) (struct link_map *, Lmid_t, uintptr_t *);
230 void (*preinit) (uintptr_t *);
231 union
232 {
233 uintptr_t (*symbind32) (Elf32_Sym *, unsigned int, uintptr_t *,
234 uintptr_t *, unsigned int *, const char *);
235 uintptr_t (*symbind64) (Elf64_Sym *, unsigned int, uintptr_t *,
236 uintptr_t *, unsigned int *, const char *);
237 };
238 union
239 {
240#ifdef ARCH_PLTENTER_MEMBERS
241 ARCH_PLTENTER_MEMBERS;
242#endif
243 };
244 union
245 {
246#ifdef ARCH_PLTEXIT_MEMBERS
247 ARCH_PLTEXIT_MEMBERS;
248#endif
249 };
250 unsigned int (*objclose) (uintptr_t *);
251
252 struct audit_ifaces *next;
253};
254
255
256/* Test whether given NAME matches any of the names of the given object. */
257extern int _dl_name_match_p (const char *__name, const struct link_map *__map)
258 attribute_hidden;
259
260/* Compute next higher prime number. */
261extern unsigned long int _dl_higher_prime_number (unsigned long int n)
262 attribute_hidden;
263
264/* A stripped down strtoul-like implementation. */
265uint64_t _dl_strtoul (const char *, char **) attribute_hidden;
266
267/* Function used as argument for `_dl_receive_error' function. The
268 arguments are the error code, error string, and the objname the
269 error occurred in. */
270typedef void (*receiver_fct) (int, const char *, const char *);
271
272/* Internal functions of the run-time dynamic linker.
273 These can be accessed if you link again the dynamic linker
274 as a shared library, as in `-lld' or `/lib/ld.so' explicitly;
275 but are not normally of interest to user programs.
276
277 The `-ldl' library functions in <dlfcn.h> provide a simple
278 user interface to run-time dynamic linking. */
279
280
281#ifndef SHARED
282# define EXTERN extern
283# define GL(name) _##name
284#else
285# define EXTERN
286# if IS_IN (rtld)
287# define GL(name) _rtld_local._##name
288# else
289# define GL(name) _rtld_global._##name
290# endif
291struct rtld_global
292{
293#endif
294 /* Don't change the order of the following elements. 'dl_loaded'
295 must remain the first element. Forever. */
296
297/* Non-shared code has no support for multiple namespaces. */
298#ifdef SHARED
299# define DL_NNS 16
300#else
301# define DL_NNS 1
302#endif
303 EXTERN struct link_namespaces
304 {
305 /* A pointer to the map for the main map. */
306 struct link_map *_ns_loaded;
307 /* Number of object in the _dl_loaded list. */
308 unsigned int _ns_nloaded;
309 /* Direct pointer to the searchlist of the main object. */
310 struct r_scope_elem *_ns_main_searchlist;
311 /* This is zero at program start to signal that the global scope map is
312 allocated by rtld. Later it keeps the size of the map. It might be
313 reset if in _dl_close if the last global object is removed. */
314 size_t _ns_global_scope_alloc;
315 /* Search table for unique objects. */
316 struct unique_sym_table
317 {
318 __rtld_lock_define_recursive (, lock)
319 struct unique_sym
320 {
321 uint32_t hashval;
322 const char *name;
323 const ElfW(Sym) *sym;
324 const struct link_map *map;
325 } *entries;
326 size_t size;
327 size_t n_elements;
328 void (*free) (void *);
329 } _ns_unique_sym_table;
330 /* Keep track of changes to each namespace' list. */
331 struct r_debug _ns_debug;
332 } _dl_ns[DL_NNS];
333 /* One higher than index of last used namespace. */
334 EXTERN size_t _dl_nns;
335
336 /* During the program run we must not modify the global data of
337 loaded shared object simultanously in two threads. Therefore we
338 protect `_dl_open' and `_dl_close' in dl-close.c.
339
340 This must be a recursive lock since the initializer function of
341 the loaded object might as well require a call to this function.
342 At this time it is not anymore a problem to modify the tables. */
343 __rtld_lock_define_recursive (EXTERN, _dl_load_lock)
344 /* This lock is used to keep __dl_iterate_phdr from inspecting the
345 list of loaded objects while an object is added to or removed
346 from that list. */
347 __rtld_lock_define_recursive (EXTERN, _dl_load_write_lock)
348
349 /* Incremented whenever something may have been added to dl_loaded. */
350 EXTERN unsigned long long _dl_load_adds;
351
352 /* The object to be initialized first. */
353 EXTERN struct link_map *_dl_initfirst;
354
355#if HP_SMALL_TIMING_AVAIL
356 /* Start time on CPU clock. */
357 EXTERN hp_timing_t _dl_cpuclock_offset;
358#endif
359
360 /* Map of shared object to be profiled. */
361 EXTERN struct link_map *_dl_profile_map;
362
363 /* Counters for the number of relocations performed. */
364 EXTERN unsigned long int _dl_num_relocations;
365 EXTERN unsigned long int _dl_num_cache_relocations;
366
367 /* List of search directories. */
368 EXTERN struct r_search_path_elem *_dl_all_dirs;
369
370 /* Structure describing the dynamic linker itself. We need to
371 reserve memory for the data the audit libraries need. */
372 EXTERN struct link_map _dl_rtld_map;
373#ifdef SHARED
374 struct auditstate audit_data[DL_NNS];
375#endif
376
377#if defined SHARED && defined _LIBC_REENTRANT \
378 && defined __rtld_lock_default_lock_recursive
379 EXTERN void (*_dl_rtld_lock_recursive) (void *);
380 EXTERN void (*_dl_rtld_unlock_recursive) (void *);
381#endif
382
383 /* Get architecture specific definitions. */
384#define PROCINFO_DECL
385#ifndef PROCINFO_CLASS
386# define PROCINFO_CLASS EXTERN
387#endif
388#include <dl-procruntime.c>
389
390 /* If loading a shared object requires that we make the stack executable
391 when it was not, we do it by calling this function.
392 It returns an errno code or zero on success. */
393 EXTERN int (*_dl_make_stack_executable_hook) (void **);
394
395 /* Prevailing state of the stack, PF_X indicating it's executable. */
396 EXTERN ElfW(Word) _dl_stack_flags;
397
398 /* Flag signalling whether there are gaps in the module ID allocation. */
399 EXTERN bool _dl_tls_dtv_gaps;
400 /* Highest dtv index currently needed. */
401 EXTERN size_t _dl_tls_max_dtv_idx;
402 /* Information about the dtv slots. */
403 EXTERN struct dtv_slotinfo_list
404 {
405 size_t len;
406 struct dtv_slotinfo_list *next;
407 struct dtv_slotinfo
408 {
409 size_t gen;
410 struct link_map *map;
411 } slotinfo[0];
412 } *_dl_tls_dtv_slotinfo_list;
413 /* Number of modules in the static TLS block. */
414 EXTERN size_t _dl_tls_static_nelem;
415 /* Size of the static TLS block. */
416 EXTERN size_t _dl_tls_static_size;
417 /* Size actually allocated in the static TLS block. */
418 EXTERN size_t _dl_tls_static_used;
419 /* Alignment requirement of the static TLS block. */
420 EXTERN size_t _dl_tls_static_align;
421
422/* Number of additional entries in the slotinfo array of each slotinfo
423 list element. A large number makes it almost certain take we never
424 have to iterate beyond the first element in the slotinfo list. */
425#define TLS_SLOTINFO_SURPLUS (62)
426
427/* Number of additional slots in the dtv allocated. */
428#define DTV_SURPLUS (14)
429
430 /* Initial dtv of the main thread, not allocated with normal malloc. */
431 EXTERN void *_dl_initial_dtv;
432 /* Generation counter for the dtv. */
433 EXTERN size_t _dl_tls_generation;
434
435 EXTERN void (*_dl_init_static_tls) (struct link_map *);
436
437 EXTERN void (*_dl_wait_lookup_done) (void);
438
439 /* Scopes to free after next THREAD_GSCOPE_WAIT (). */
440 EXTERN struct dl_scope_free_list
441 {
442 size_t count;
443 void *list[50];
444 } *_dl_scope_free_list;
445#if !THREAD_GSCOPE_IN_TCB
446 EXTERN int _dl_thread_gscope_count;
447#endif
448#ifdef SHARED
449};
450# define __rtld_global_attribute__
451# if IS_IN (rtld)
452# ifdef HAVE_SDATA_SECTION
453# define __rtld_local_attribute__ \
454 __attribute__ ((visibility ("hidden"), section (".sdata")))
455# undef __rtld_global_attribute__
456# define __rtld_global_attribute__ __attribute__ ((section (".sdata")))
457# else
458# define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
459# endif
460extern struct rtld_global _rtld_local __rtld_local_attribute__;
461# undef __rtld_local_attribute__
462# endif
463extern struct rtld_global _rtld_global __rtld_global_attribute__;
464# undef __rtld_global_attribute__
465#endif
466
467#ifndef SHARED
468# define GLRO(name) _##name
469#else
470# if IS_IN (rtld)
471# define GLRO(name) _rtld_local_ro._##name
472# else
473# define GLRO(name) _rtld_global_ro._##name
474# endif
475struct rtld_global_ro
476{
477#endif
478
479 /* If nonzero the appropriate debug information is printed. */
480 EXTERN int _dl_debug_mask;
481#define DL_DEBUG_LIBS (1 << 0)
482#define DL_DEBUG_IMPCALLS (1 << 1)
483#define DL_DEBUG_BINDINGS (1 << 2)
484#define DL_DEBUG_SYMBOLS (1 << 3)
485#define DL_DEBUG_VERSIONS (1 << 4)
486#define DL_DEBUG_RELOC (1 << 5)
487#define DL_DEBUG_FILES (1 << 6)
488#define DL_DEBUG_STATISTICS (1 << 7)
489#define DL_DEBUG_UNUSED (1 << 8)
490#define DL_DEBUG_SCOPES (1 << 9)
491/* These two are used only internally. */
492#define DL_DEBUG_HELP (1 << 10)
493#define DL_DEBUG_PRELINK (1 << 11)
494
495 /* OS version. */
496 EXTERN unsigned int _dl_osversion;
497 /* Platform name. */
498 EXTERN const char *_dl_platform;
499 EXTERN size_t _dl_platformlen;
500
501 /* Cached value of `getpagesize ()'. */
502 EXTERN size_t _dl_pagesize;
503
504 /* Do we read from ld.so.cache? */
505 EXTERN int _dl_inhibit_cache;
506
507 /* Copy of the content of `_dl_main_searchlist' at startup time. */
508 EXTERN struct r_scope_elem _dl_initial_searchlist;
509
510 /* CLK_TCK as reported by the kernel. */
511 EXTERN int _dl_clktck;
512
513 /* If nonzero print warnings messages. */
514 EXTERN int _dl_verbose;
515
516 /* File descriptor to write debug messages to. */
517 EXTERN int _dl_debug_fd;
518
519 /* Do we do lazy relocations? */
520 EXTERN int _dl_lazy;
521
522 /* Nonzero if runtime lookups should not update the .got/.plt. */
523 EXTERN int _dl_bind_not;
524
525 /* Nonzero if references should be treated as weak during runtime
526 linking. */
527 EXTERN int _dl_dynamic_weak;
528
529 /* Default floating-point control word. */
530 EXTERN fpu_control_t _dl_fpu_control;
531
532 /* Expected cache ID. */
533 EXTERN int _dl_correct_cache_id;
534
535 /* Mask for hardware capabilities that are available. */
536 EXTERN uint64_t _dl_hwcap;
537
538#if !HAVE_TUNABLES
539 /* Mask for important hardware capabilities we honour. */
540 EXTERN uint64_t _dl_hwcap_mask;
541#endif
542
543#ifdef HAVE_AUX_VECTOR
544 /* Pointer to the auxv list supplied to the program at startup. */
545 EXTERN ElfW(auxv_t) *_dl_auxv;
546#endif
547
548 /* Get architecture specific definitions. */
549#include <dl-procinfo.c>
550
551 /* Names of shared object for which the RPATH should be ignored. */
552 EXTERN const char *_dl_inhibit_rpath;
553
554 /* Location of the binary. */
555 EXTERN const char *_dl_origin_path;
556
557 /* -1 if the dynamic linker should honor library load bias,
558 0 if not, -2 use the default (honor biases for normal
559 binaries, don't honor for PIEs). */
560 EXTERN ElfW(Addr) _dl_use_load_bias;
561
562 /* Name of the shared object to be profiled (if any). */
563 EXTERN const char *_dl_profile;
564 /* Filename of the output file. */
565 EXTERN const char *_dl_profile_output;
566 /* Name of the object we want to trace the prelinking. */
567 EXTERN const char *_dl_trace_prelink;
568 /* Map of shared object to be prelink traced. */
569 EXTERN struct link_map *_dl_trace_prelink_map;
570
571 /* All search directories defined at startup. This is assigned a
572 non-NULL pointer by the ld.so startup code (after initialization
573 to NULL), so this can also serve as an indicator whether a copy
574 of ld.so is initialized and active. See the rtld_active function
575 below. */
576 EXTERN struct r_search_path_elem *_dl_init_all_dirs;
577
578#ifdef NEED_DL_SYSINFO
579 /* Syscall handling improvements. This is very specific to x86. */
580 EXTERN uintptr_t _dl_sysinfo;
581#endif
582
583#ifdef NEED_DL_SYSINFO_DSO
584 /* The vsyscall page is a virtual DSO pre-mapped by the kernel.
585 This points to its ELF header. */
586 EXTERN const ElfW(Ehdr) *_dl_sysinfo_dso;
587
588 /* At startup time we set up the normal DSO data structure for it,
589 and this points to it. */
590 EXTERN struct link_map *_dl_sysinfo_map;
591#endif
592
593 /* Mask for more hardware capabilities that are available on some
594 platforms. */
595 EXTERN uint64_t _dl_hwcap2;
596
597#ifdef SHARED
598 /* We add a function table to _rtld_global which is then used to
599 call the function instead of going through the PLT. The result
600 is that we can avoid exporting the functions and we do not jump
601 PLT relocations in libc.so. */
602 void (*_dl_debug_printf) (const char *, ...)
603 __attribute__ ((__format__ (__printf__, 1, 2)));
604 void (*_dl_mcount) (ElfW(Addr) frompc, ElfW(Addr) selfpc);
605 lookup_t (*_dl_lookup_symbol_x) (const char *, struct link_map *,
606 const ElfW(Sym) **, struct r_scope_elem *[],
607 const struct r_found_version *, int, int,
608 struct link_map *);
609 void *(*_dl_open) (const char *file, int mode, const void *caller_dlopen,
610 Lmid_t nsid, int argc, char *argv[], char *env[]);
611 void (*_dl_close) (void *map);
612 void *(*_dl_tls_get_addr_soft) (struct link_map *);
613#ifdef HAVE_DL_DISCOVER_OSVERSION
614 int (*_dl_discover_osversion) (void);
615#endif
616
617 /* List of auditing interfaces. */
618 struct audit_ifaces *_dl_audit;
619 unsigned int _dl_naudit;
620};
621# define __rtld_global_attribute__
622# if IS_IN (rtld)
623# define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
624extern struct rtld_global_ro _rtld_local_ro
625 attribute_relro __rtld_local_attribute__;
626extern struct rtld_global_ro _rtld_global_ro
627 attribute_relro __rtld_global_attribute__;
628# undef __rtld_local_attribute__
629# else
630/* We cheat a bit here. We declare the variable as as const even
631 though it is at startup. */
632extern const struct rtld_global_ro _rtld_global_ro
633 attribute_relro __rtld_global_attribute__;
634# endif
635# undef __rtld_global_attribute__
636#endif
637#undef EXTERN
638
639#ifndef SHARED
640/* dl-support.c defines these and initializes them early on. */
641extern const ElfW(Phdr) *_dl_phdr;
642extern size_t _dl_phnum;
643#endif
644
645/* This is the initial value of GL(dl_make_stack_executable_hook).
646 A threads library can change it. */
647extern int _dl_make_stack_executable (void **stack_endp);
648rtld_hidden_proto (_dl_make_stack_executable)
649
650/* Variable pointing to the end of the stack (or close to it). This value
651 must be constant over the runtime of the application. Some programs
652 might use the variable which results in copy relocations on some
653 platforms. But this does not matter, ld.so can always use the local
654 copy. */
655extern void *__libc_stack_end
656#ifndef LIBC_STACK_END_NOT_RELRO
657 attribute_relro
658#endif
659 ;
660rtld_hidden_proto (__libc_stack_end)
661
662/* Parameters passed to the dynamic linker. */
663extern int _dl_argc attribute_hidden attribute_relro;
664extern char **_dl_argv
665#ifndef DL_ARGV_NOT_RELRO
666 attribute_relro
667#endif
668 ;
669rtld_hidden_proto (_dl_argv)
670#if IS_IN (rtld)
671extern unsigned int _dl_skip_args attribute_hidden
672# ifndef DL_ARGV_NOT_RELRO
673 attribute_relro
674# endif
675 ;
676extern unsigned int _dl_skip_args_internal attribute_hidden
677# ifndef DL_ARGV_NOT_RELRO
678 attribute_relro
679# endif
680 ;
681#endif
682#define rtld_progname _dl_argv[0]
683
684/* Flag set at startup and cleared when the last initializer has run. */
685extern int _dl_starting_up;
686weak_extern (_dl_starting_up)
687rtld_hidden_proto (_dl_starting_up)
688
689/* Random data provided by the kernel. */
690extern void *_dl_random attribute_hidden attribute_relro;
691
692/* OS-dependent function to open the zero-fill device. */
693extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */
694
695
696/* Write message on the debug file descriptor. The parameters are
697 interpreted as for a `printf' call. All the lines start with a
698 tag showing the PID. */
699extern void _dl_debug_printf (const char *fmt, ...)
700 __attribute__ ((__format__ (__printf__, 1, 2))) attribute_hidden;
701
702/* Write message on the debug file descriptor. The parameters are
703 interpreted as for a `printf' call. All the lines buf the first
704 start with a tag showing the PID. */
705extern void _dl_debug_printf_c (const char *fmt, ...)
706 __attribute__ ((__format__ (__printf__, 1, 2))) attribute_hidden;
707
708
709/* Write a message on the specified descriptor FD. The parameters are
710 interpreted as for a `printf' call. */
711#if IS_IN (rtld) || !defined (SHARED)
712extern void _dl_dprintf (int fd, const char *fmt, ...)
713 __attribute__ ((__format__ (__printf__, 2, 3)))
714 attribute_hidden;
715#else
716__attribute__ ((always_inline, __format__ (__printf__, 2, 3)))
717static inline void
718_dl_dprintf (int fd, const char *fmt, ...)
719{
720 /* Use local declaration to avoid includign <stdio.h>. */
721 extern int __dprintf(int fd, const char *format, ...) attribute_hidden;
722 __dprintf (fd, fmt, __builtin_va_arg_pack ());
723}
724#endif
725
726/* Write a message on the specified descriptor standard output. The
727 parameters are interpreted as for a `printf' call. */
728#define _dl_printf(fmt, args...) \
729 _dl_dprintf (STDOUT_FILENO, fmt, ##args)
730
731/* Write a message on the specified descriptor standard error. The
732 parameters are interpreted as for a `printf' call. */
733#define _dl_error_printf(fmt, args...) \
734 _dl_dprintf (STDERR_FILENO, fmt, ##args)
735
736/* Write a message on the specified descriptor standard error and exit
737 the program. The parameters are interpreted as for a `printf' call. */
738#define _dl_fatal_printf(fmt, args...) \
739 do \
740 { \
741 _dl_dprintf (STDERR_FILENO, fmt, ##args); \
742 _exit (127); \
743 } \
744 while (1)
745
746
747/* An exception raised by the _dl_signal_error function family and
748 caught by _dl_catch_error function family. Exceptions themselves
749 are copied as part of the raise operation, but the strings are
750 not. */
751struct dl_exception
752{
753 const char *objname;
754 const char *errstring;
755
756 /* This buffer typically stores both objname and errstring
757 above. */
758 char *message_buffer;
759};
760
761/* Creates a new exception. This calls malloc; if allocation fails,
762 dummy values are inserted. OBJECT is the name of the problematical
763 shared object, or null if its a general problem. ERRSTRING is a
764 string describing the specific problem. */
765void _dl_exception_create (struct dl_exception *, const char *object,
766 const char *errstring)
767 __attribute__ ((nonnull (1, 3)));
768rtld_hidden_proto (_dl_exception_create)
769
770/* Like _dl_exception_create, but create errstring from a format
771 string FMT. Currently, only "%s" and "%%" are supported as format
772 directives. */
773void _dl_exception_create_format (struct dl_exception *, const char *objname,
774 const char *fmt, ...)
775 __attribute__ ((nonnull (1, 3), format (printf, 3, 4)));
776rtld_hidden_proto (_dl_exception_create_format)
777
778/* Deallocate the exception, freeing allocated buffers (if
779 possible). */
780void _dl_exception_free (struct dl_exception *)
781 __attribute__ ((nonnull (1)));
782rtld_hidden_proto (_dl_exception_free)
783
784/* This function is called by all the internal dynamic linker
785 functions when they encounter an error. ERRCODE is either an
786 `errno' code or zero; it specifies the return value of
787 _dl_catch_error. OCCASION is included in the error message if the
788 process is terminated immediately. */
789void _dl_signal_exception (int errcode, struct dl_exception *,
790 const char *occasion)
791 __attribute__ ((__noreturn__));
792libc_hidden_proto (_dl_signal_exception)
793
794/* Like _dl_signal_exception, but creates the exception first. */
795extern void _dl_signal_error (int errcode, const char *object,
796 const char *occasion, const char *errstring)
797 __attribute__ ((__noreturn__));
798libc_hidden_proto (_dl_signal_error)
799
800/* Like _dl_signal_exception, but may return when called in the
801 context of _dl_receive_error. This is only used during ld.so
802 bootstrap. In static and profiled builds, this is equivalent to
803 _dl_signal_exception. */
804#if IS_IN (rtld)
805extern void _dl_signal_cexception (int errcode, struct dl_exception *,
806 const char *occasion) attribute_hidden;
807#else
808__attribute__ ((always_inline))
809static inline void
810_dl_signal_cexception (int errcode, struct dl_exception *exception,
811 const char *occasion)
812{
813 _dl_signal_exception (errcode, exception, occasion);
814}
815#endif
816
817/* See _dl_signal_cexception above. */
818#if IS_IN (rtld)
819extern void _dl_signal_cerror (int errcode, const char *object,
820 const char *occasion, const char *errstring)
821 attribute_hidden;
822#else
823__attribute__ ((always_inline))
824static inline void
825_dl_signal_cerror (int errcode, const char *object,
826 const char *occasion, const char *errstring)
827{
828 _dl_signal_error (errcode, object, occasion, errstring);
829}
830#endif
831
832/* Call OPERATE, receiving errors from `dl_signal_cerror'. Unlike
833 `_dl_catch_error' the operation is resumed after the OPERATE
834 function returns.
835 ARGS is passed as argument to OPERATE. */
836extern void _dl_receive_error (receiver_fct fct, void (*operate) (void *),
837 void *args) attribute_hidden;
838
839/* Call OPERATE, catching errors from `_dl_signal_error' and related
840 functions. If there is no error, *ERRSTRING is set to null. If
841 there is an error, *ERRSTRING is set to a string constructed from
842 the strings passed to _dl_signal_error, and the error code passed
843 is the return value and *OBJNAME is set to the object name which
844 experienced the problems. ERRSTRING if nonzero points to a
845 malloc'ed string which the caller has to free after use. ARGS is
846 passed as argument to OPERATE. MALLOCEDP is set to true only if
847 the returned string is allocated using the libc's malloc. */
848extern int _dl_catch_error (const char **objname, const char **errstring,
849 bool *mallocedp, void (*operate) (void *),
850 void *args);
851libc_hidden_proto (_dl_catch_error)
852
853/* Call OPERATE (ARGS). If no error occurs, set *EXCEPTION to zero.
854 Otherwise, store a copy of the raised exception in *EXCEPTION,
855 which has to be freed by _dl_exception_free. */
856int _dl_catch_exception (struct dl_exception *exception,
857 void (*operate) (void *), void *args);
858libc_hidden_proto (_dl_catch_exception)
859
860/* Open the shared object NAME and map in its segments.
861 LOADER's DT_RPATH is used in searching for NAME.
862 If the object is already opened, returns its existing map. */
863extern struct link_map *_dl_map_object (struct link_map *loader,
864 const char *name,
865 int type, int trace_mode, int mode,
866 Lmid_t nsid) attribute_hidden;
867
868/* Call _dl_map_object on the dependencies of MAP, and set up
869 MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously
870 loaded objects that will be inserted into MAP->l_searchlist after MAP
871 but before its dependencies. */
872extern void _dl_map_object_deps (struct link_map *map,
873 struct link_map **preloads,
874 unsigned int npreloads, int trace_mode,
875 int open_mode)
876 attribute_hidden;
877
878/* Cache the locations of MAP's hash table. */
879extern void _dl_setup_hash (struct link_map *map) attribute_hidden;
880
881
882/* Collect the directories in the search path for LOADER's dependencies.
883 The data structure is defined in <dlfcn.h>. If COUNTING is true,
884 SI->dls_cnt and SI->dls_size are set; if false, those must be as set
885 by a previous call with COUNTING set, and SI must point to SI->dls_size
886 bytes to be used in filling in the result. */
887extern void _dl_rtld_di_serinfo (struct link_map *loader,
888 Dl_serinfo *si, bool counting);
889
890
891/* Search loaded objects' symbol tables for a definition of the symbol
892 referred to by UNDEF. *SYM is the symbol table entry containing the
893 reference; it is replaced with the defining symbol, and the base load
894 address of the defining object is returned. SYMBOL_SCOPE is a
895 null-terminated list of object scopes to search; each object's
896 l_searchlist (i.e. the segment of the dependency tree starting at that
897 object) is searched in turn. REFERENCE_NAME should name the object
898 containing the reference; it is used in error messages.
899 TYPE_CLASS describes the type of symbol we are looking for. */
900enum
901 {
902 /* If necessary add dependency between user and provider object. */
903 DL_LOOKUP_ADD_DEPENDENCY = 1,
904 /* Return most recent version instead of default version for
905 unversioned lookup. */
906 DL_LOOKUP_RETURN_NEWEST = 2,
907 /* Set if dl_lookup* called with GSCOPE lock held. */
908 DL_LOOKUP_GSCOPE_LOCK = 4,
909 };
910
911/* Lookup versioned symbol. */
912extern lookup_t _dl_lookup_symbol_x (const char *undef,
913 struct link_map *undef_map,
914 const ElfW(Sym) **sym,
915 struct r_scope_elem *symbol_scope[],
916 const struct r_found_version *version,
917 int type_class, int flags,
918 struct link_map *skip_map)
919 attribute_hidden;
920
921
922/* Add the new link_map NEW to the end of the namespace list. */
923extern void _dl_add_to_namespace_list (struct link_map *new, Lmid_t nsid)
924 attribute_hidden;
925
926/* Allocate a `struct link_map' for a new object being loaded. */
927extern struct link_map *_dl_new_object (char *realname, const char *libname,
928 int type, struct link_map *loader,
929 int mode, Lmid_t nsid)
930 attribute_hidden;
931
932/* Relocate the given object (if it hasn't already been).
933 SCOPE is passed to _dl_lookup_symbol in symbol lookups.
934 If RTLD_LAZY is set in RELOC-MODE, don't relocate its PLT. */
935extern void _dl_relocate_object (struct link_map *map,
936 struct r_scope_elem *scope[],
937 int reloc_mode, int consider_profiling)
938 attribute_hidden;
939
940/* Protect PT_GNU_RELRO area. */
941extern void _dl_protect_relro (struct link_map *map) attribute_hidden;
942
943/* Call _dl_signal_error with a message about an unhandled reloc type.
944 TYPE is the result of ELFW(R_TYPE) (r_info), i.e. an R_<CPU>_* value.
945 PLT is nonzero if this was a PLT reloc; it just affects the message. */
946extern void _dl_reloc_bad_type (struct link_map *map,
947 unsigned int type, int plt)
948 attribute_hidden __attribute__ ((__noreturn__));
949
950/* Resolve conflicts if prelinking. */
951extern void _dl_resolve_conflicts (struct link_map *l,
952 ElfW(Rela) *conflict,
953 ElfW(Rela) *conflictend)
954 attribute_hidden;
955
956/* Check the version dependencies of all objects available through
957 MAP. If VERBOSE print some more diagnostics. */
958extern int _dl_check_all_versions (struct link_map *map, int verbose,
959 int trace_mode) attribute_hidden;
960
961/* Check the version dependencies for MAP. If VERBOSE print some more
962 diagnostics. */
963extern int _dl_check_map_versions (struct link_map *map, int verbose,
964 int trace_mode) attribute_hidden;
965
966/* Initialize the object in SCOPE by calling the constructors with
967 ARGC, ARGV, and ENV as the parameters. */
968extern void _dl_init (struct link_map *main_map, int argc, char **argv,
969 char **env) attribute_hidden;
970
971/* Call the finalizer functions of all shared objects whose
972 initializer functions have completed. */
973extern void _dl_fini (void) attribute_hidden;
974
975/* Sort array MAPS according to dependencies of the contained objects. */
976extern void _dl_sort_maps (struct link_map **maps, unsigned int nmaps,
977 char *used, bool for_fini) attribute_hidden;
978
979/* The dynamic linker calls this function before and having changing
980 any shared object mappings. The `r_state' member of `struct r_debug'
981 says what change is taking place. This function's address is
982 the value of the `r_brk' member. */
983extern void _dl_debug_state (void);
984rtld_hidden_proto (_dl_debug_state)
985
986/* Initialize `struct r_debug' if it has not already been done. The
987 argument is the run-time load address of the dynamic linker, to be put
988 in the `r_ldbase' member. Returns the address of the structure. */
989extern struct r_debug *_dl_debug_initialize (ElfW(Addr) ldbase, Lmid_t ns)
990 attribute_hidden;
991
992/* Initialize the basic data structure for the search paths. */
993extern void _dl_init_paths (const char *library_path) attribute_hidden;
994
995/* Gather the information needed to install the profiling tables and start
996 the timers. */
997extern void _dl_start_profile (void) attribute_hidden;
998
999/* The actual functions used to keep book on the calls. */
1000extern void _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc);
1001rtld_hidden_proto (_dl_mcount)
1002
1003/* This function is simply a wrapper around the _dl_mcount function
1004 which does not require a FROMPC parameter since this is the
1005 calling function. */
1006extern void _dl_mcount_wrapper (void *selfpc);
1007
1008/* Show the members of the auxiliary array passed up from the kernel. */
1009extern void _dl_show_auxv (void) attribute_hidden;
1010
1011/* Return all environment variables starting with `LD_', one after the
1012 other. */
1013extern char *_dl_next_ld_env_entry (char ***position) attribute_hidden;
1014
1015/* Return an array with the names of the important hardware capabilities. */
1016extern const struct r_strlenpair *_dl_important_hwcaps (const char *platform,
1017 size_t paltform_len,
1018 size_t *sz,
1019 size_t *max_capstrlen)
1020 attribute_hidden;
1021
1022/* Look up NAME in ld.so.cache and return the file name stored there,
1023 or null if none is found. Caller must free returned string. */
1024extern char *_dl_load_cache_lookup (const char *name) attribute_hidden;
1025
1026/* If the system does not support MAP_COPY we cannot leave the file open
1027 all the time since this would create problems when the file is replaced.
1028 Therefore we provide this function to close the file and open it again
1029 once needed. */
1030extern void _dl_unload_cache (void) attribute_hidden;
1031
1032/* System-dependent function to read a file's whole contents in the
1033 most convenient manner available. *SIZEP gets the size of the
1034 file. On error MAP_FAILED is returned. */
1035extern void *_dl_sysdep_read_whole_file (const char *file, size_t *sizep,
1036 int prot) attribute_hidden;
1037
1038/* System-specific function to do initial startup for the dynamic linker.
1039 After this, file access calls and getenv must work. This is responsible
1040 for setting __libc_enable_secure if we need to be secure (e.g. setuid),
1041 and for setting _dl_argc and _dl_argv, and then calling _dl_main. */
1042extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
1043 void (*dl_main) (const ElfW(Phdr) *phdr,
1044 ElfW(Word) phnum,
1045 ElfW(Addr) *user_entry,
1046 ElfW(auxv_t) *auxv))
1047 attribute_hidden;
1048
1049extern void _dl_sysdep_start_cleanup (void) attribute_hidden;
1050
1051
1052/* Determine next available module ID. */
1053extern size_t _dl_next_tls_modid (void) attribute_hidden;
1054
1055/* Count the modules with TLS segments. */
1056extern size_t _dl_count_modids (void) attribute_hidden;
1057
1058/* Calculate offset of the TLS blocks in the static TLS block. */
1059extern void _dl_determine_tlsoffset (void) attribute_hidden;
1060
1061#ifndef SHARED
1062/* Set up the TCB for statically linked applications. This is called
1063 early during startup because we always use TLS (for errno and the
1064 stack protector, among other things). */
1065void __libc_setup_tls (void);
1066
1067# if ENABLE_STATIC_PIE
1068/* Relocate static executable with PIE. */
1069extern void _dl_relocate_static_pie (void) attribute_hidden;
1070
1071/* Get a pointer to _dl_main_map. */
1072extern struct link_map * _dl_get_dl_main_map (void)
1073 __attribute__ ((visibility ("hidden")));
1074# else
1075# define _dl_relocate_static_pie()
1076# endif
1077#endif
1078
1079/* Initialization of libpthread for statically linked applications.
1080 If libpthread is not linked in, this is an empty function. */
1081void __pthread_initialize_minimal (void) weak_function;
1082
1083/* Allocate memory for static TLS block (unless MEM is nonzero) and dtv. */
1084extern void *_dl_allocate_tls (void *mem);
1085rtld_hidden_proto (_dl_allocate_tls)
1086
1087/* Get size and alignment requirements of the static TLS block. */
1088extern void _dl_get_tls_static_info (size_t *sizep, size_t *alignp);
1089
1090extern void _dl_allocate_static_tls (struct link_map *map) attribute_hidden;
1091
1092/* These are internal entry points to the two halves of _dl_allocate_tls,
1093 only used within rtld.c itself at startup time. */
1094extern void *_dl_allocate_tls_storage (void) attribute_hidden;
1095extern void *_dl_allocate_tls_init (void *);
1096rtld_hidden_proto (_dl_allocate_tls_init)
1097
1098/* Deallocate memory allocated with _dl_allocate_tls. */
1099extern void _dl_deallocate_tls (void *tcb, bool dealloc_tcb);
1100rtld_hidden_proto (_dl_deallocate_tls)
1101
1102extern void _dl_nothread_init_static_tls (struct link_map *) attribute_hidden;
1103
1104/* Find origin of the executable. */
1105extern const char *_dl_get_origin (void) attribute_hidden;
1106
1107/* Count DSTs. */
1108extern size_t _dl_dst_count (const char *name) attribute_hidden;
1109
1110/* Substitute DST values. */
1111extern char *_dl_dst_substitute (struct link_map *l, const char *name,
1112 char *result) attribute_hidden;
1113
1114/* Open the shared object NAME, relocate it, and run its initializer if it
1115 hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If
1116 the object is already opened, returns its existing map. */
1117extern void *_dl_open (const char *name, int mode, const void *caller,
1118 Lmid_t nsid, int argc, char *argv[], char *env[])
1119 attribute_hidden;
1120
1121/* Free or queue for freeing scope OLD. If other threads might be
1122 in the middle of _dl_fixup, _dl_profile_fixup or dl*sym using the
1123 old scope, OLD can't be freed until no thread is using it. */
1124extern int _dl_scope_free (void *) attribute_hidden;
1125
1126/* Add module to slot information data. */
1127extern void _dl_add_to_slotinfo (struct link_map *l) attribute_hidden;
1128
1129/* Update slot information data for at least the generation of the
1130 module with the given index. */
1131extern struct link_map *_dl_update_slotinfo (unsigned long int req_modid)
1132 attribute_hidden;
1133
1134/* Look up the module's TLS block as for __tls_get_addr,
1135 but never touch anything. Return null if it's not allocated yet. */
1136extern void *_dl_tls_get_addr_soft (struct link_map *l) attribute_hidden;
1137
1138extern int _dl_addr_inside_object (struct link_map *l, const ElfW(Addr) addr)
1139 attribute_hidden;
1140
1141/* Show show of an object. */
1142extern void _dl_show_scope (struct link_map *new, int from)
1143 attribute_hidden;
1144
1145extern struct link_map *_dl_find_dso_for_object (const ElfW(Addr) addr);
1146rtld_hidden_proto (_dl_find_dso_for_object)
1147
1148/* Initialization which is normally done by the dynamic linker. */
1149extern void _dl_non_dynamic_init (void)
1150 attribute_hidden;
1151
1152/* Used by static binaries to check the auxiliary vector. */
1153extern void _dl_aux_init (ElfW(auxv_t) *av)
1154 attribute_hidden;
1155
1156/* Return true if the ld.so copy in this namespace is actually active
1157 and working. If false, the dl_open/dlfcn hooks have to be used to
1158 call into the outer dynamic linker (which happens after static
1159 dlopen). */
1160#ifdef SHARED
1161static inline bool
1162rtld_active (void)
1163{
1164 /* The default-initialized variable does not have a non-zero
1165 dl_init_all_dirs member, so this allows us to recognize an
1166 initialized and active ld.so copy. */
1167 return GLRO(dl_init_all_dirs) != NULL;
1168}
1169#endif
1170
1171__END_DECLS
1172
1173#endif /* ldsodefs.h */
1174