1/* Run-time dynamic linker data structures for loaded ELF shared objects.
2 Copyright (C) 1995-2016 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) ((map) ? (map)->l_addr : 0)
70
71/* On some architectures a pointer to a function is not just a pointer
72 to the actual code of the function but rather an architecture
73 specific descriptor. */
74#ifndef ELF_FUNCTION_PTR_IS_SPECIAL
75# define DL_SYMBOL_ADDRESS(map, ref) \
76 (void *) (LOOKUP_VALUE_ADDRESS (map) + ref->st_value)
77# define DL_LOOKUP_ADDRESS(addr) ((ElfW(Addr)) (addr))
78# define DL_CALL_DT_INIT(map, start, argc, argv, env) \
79 ((init_t) (start)) (argc, argv, env)
80# define DL_CALL_DT_FINI(map, start) ((fini_t) (start)) ()
81#endif
82
83/* On some architectures dladdr can't use st_size of all symbols this way. */
84#define DL_ADDR_SYM_MATCH(L, SYM, MATCHSYM, ADDR) \
85 ((ADDR) >= (L)->l_addr + (SYM)->st_value \
86 && ((((SYM)->st_shndx == SHN_UNDEF || (SYM)->st_size == 0) \
87 && (ADDR) == (L)->l_addr + (SYM)->st_value) \
88 || (ADDR) < (L)->l_addr + (SYM)->st_value + (SYM)->st_size) \
89 && ((MATCHSYM) == NULL || (MATCHSYM)->st_value < (SYM)->st_value))
90
91/* According to the ELF gABI no STV_HIDDEN or STV_INTERNAL symbols are
92 expected to be present in dynamic symbol tables as they should have
93 been either removed or converted to STB_LOCAL binding by the static
94 linker. However some GNU binutils versions produce such symbols in
95 some cases. To prevent such symbols present in a buggy binary from
96 preempting global symbols we filter them out with this predicate. */
97static __always_inline bool
98dl_symbol_visibility_binds_local_p (const ElfW(Sym) *sym)
99{
100 return (ELFW(ST_VISIBILITY) (sym->st_other) == STV_HIDDEN
101 || ELFW(ST_VISIBILITY) (sym->st_other) == STV_INTERNAL);
102}
103
104/* Unmap a loaded object, called by _dl_close (). */
105#ifndef DL_UNMAP_IS_SPECIAL
106# define DL_UNMAP(map) _dl_unmap_segments (map)
107#endif
108
109/* By default we do not need special support to initialize DSOs loaded
110 by statically linked binaries. */
111#ifndef DL_STATIC_INIT
112# define DL_STATIC_INIT(map)
113#endif
114
115/* Reloc type classes as returned by elf_machine_type_class().
116 ELF_RTYPE_CLASS_PLT means this reloc should not be satisfied by
117 some PLT symbol, ELF_RTYPE_CLASS_COPY means this reloc should not be
118 satisfied by any symbol in the executable. Some architectures do
119 not support copy relocations. In this case we define the macro to
120 zero so that the code for handling them gets automatically optimized
121 out. ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA means address of protected
122 data defined in the shared library may be external, i.e., due to copy
123 relocation. */
124#define ELF_RTYPE_CLASS_PLT 1
125#ifndef DL_NO_COPY_RELOCS
126# define ELF_RTYPE_CLASS_COPY 2
127#else
128# define ELF_RTYPE_CLASS_COPY 0
129#endif
130/* If DL_EXTERN_PROTECTED_DATA is defined, address of protected data
131 defined in the shared library may be external, i.e., due to copy
132 relocation. */
133#ifdef DL_EXTERN_PROTECTED_DATA
134# define ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA 4
135#else
136# define ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA 0
137#endif
138
139/* ELF uses the PF_x macros to specify the segment permissions, mmap
140 uses PROT_xxx. In most cases the three macros have the values 1, 2,
141 and 3 but not in a matching order. The following macros allows
142 converting from the PF_x values to PROT_xxx values. */
143#define PF_TO_PROT \
144 ((PROT_READ << (PF_R * 4)) \
145 | (PROT_WRITE << (PF_W * 4)) \
146 | (PROT_EXEC << (PF_X * 4)) \
147 | ((PROT_READ | PROT_WRITE) << ((PF_R | PF_W) * 4)) \
148 | ((PROT_READ | PROT_EXEC) << ((PF_R | PF_X) * 4)) \
149 | ((PROT_WRITE | PROT_EXEC) << (PF_W | PF_X) * 4) \
150 | ((PROT_READ | PROT_WRITE | PROT_EXEC) << ((PF_R | PF_W | PF_X) * 4)))
151
152/* The filename itself, or the main program name, if available. */
153#define DSO_FILENAME(name) ((name)[0] ? (name) \
154 : (rtld_progname ?: "<main program>"))
155
156#define RTLD_PROGNAME (rtld_progname ?: "<program name unknown>")
157
158/* For the version handling we need an array with only names and their
159 hash values. */
160struct r_found_version
161 {
162 const char *name;
163 ElfW(Word) hash;
164
165 int hidden;
166 const char *filename;
167 };
168
169/* We want to cache information about the searches for shared objects. */
170
171enum r_dir_status { unknown, nonexisting, existing };
172
173struct r_search_path_elem
174 {
175 /* This link is only used in the `all_dirs' member of `r_search_path'. */
176 struct r_search_path_elem *next;
177
178 /* Strings saying where the definition came from. */
179 const char *what;
180 const char *where;
181
182 /* Basename for this search path element. The string must end with
183 a slash character. */
184 const char *dirname;
185 size_t dirnamelen;
186
187 enum r_dir_status status[0];
188 };
189
190struct r_strlenpair
191 {
192 const char *str;
193 size_t len;
194 };
195
196
197/* A data structure for a simple single linked list of strings. */
198struct libname_list
199 {
200 const char *name; /* Name requested (before search). */
201 struct libname_list *next; /* Link to next name for this object. */
202 int dont_free; /* Flag whether this element should be freed
203 if the object is not entirely unloaded. */
204 };
205
206
207/* Bit masks for the objects which valid callers can come from to
208 functions with restricted interface. */
209enum allowmask
210 {
211 allow_libc = 1,
212 allow_libdl = 2,
213 allow_libpthread = 4,
214 allow_ldso = 8
215 };
216
217
218struct audit_ifaces
219{
220 void (*activity) (uintptr_t *, unsigned int);
221 char *(*objsearch) (const char *, uintptr_t *, unsigned int);
222 unsigned int (*objopen) (struct link_map *, Lmid_t, uintptr_t *);
223 void (*preinit) (uintptr_t *);
224 union
225 {
226 uintptr_t (*symbind32) (Elf32_Sym *, unsigned int, uintptr_t *,
227 uintptr_t *, unsigned int *, const char *);
228 uintptr_t (*symbind64) (Elf64_Sym *, unsigned int, uintptr_t *,
229 uintptr_t *, unsigned int *, const char *);
230 };
231 union
232 {
233#ifdef ARCH_PLTENTER_MEMBERS
234 ARCH_PLTENTER_MEMBERS;
235#endif
236 };
237 union
238 {
239#ifdef ARCH_PLTEXIT_MEMBERS
240 ARCH_PLTEXIT_MEMBERS;
241#endif
242 };
243 unsigned int (*objclose) (uintptr_t *);
244
245 struct audit_ifaces *next;
246};
247
248
249/* Test whether given NAME matches any of the names of the given object. */
250extern int _dl_name_match_p (const char *__name, const struct link_map *__map)
251 internal_function attribute_hidden;
252
253/* Compute next higher prime number. */
254extern unsigned long int _dl_higher_prime_number (unsigned long int n)
255 internal_function attribute_hidden;
256
257/* Function used as argument for `_dl_receive_error' function. The
258 arguments are the error code, error string, and the objname the
259 error occurred in. */
260typedef void (*receiver_fct) (int, const char *, const char *);
261
262/* Internal functions of the run-time dynamic linker.
263 These can be accessed if you link again the dynamic linker
264 as a shared library, as in `-lld' or `/lib/ld.so' explicitly;
265 but are not normally of interest to user programs.
266
267 The `-ldl' library functions in <dlfcn.h> provide a simple
268 user interface to run-time dynamic linking. */
269
270
271#ifndef SHARED
272# define EXTERN extern
273# define GL(name) _##name
274#else
275# define EXTERN
276# if IS_IN (rtld)
277# define GL(name) _rtld_local._##name
278# else
279# define GL(name) _rtld_global._##name
280# endif
281struct rtld_global
282{
283#endif
284 /* Don't change the order of the following elements. 'dl_loaded'
285 must remain the first element. Forever. */
286
287/* Non-shared code has no support for multiple namespaces. */
288#ifdef SHARED
289# define DL_NNS 16
290#else
291# define DL_NNS 1
292#endif
293 EXTERN struct link_namespaces
294 {
295 /* A pointer to the map for the main map. */
296 struct link_map *_ns_loaded;
297 /* Number of object in the _dl_loaded list. */
298 unsigned int _ns_nloaded;
299 /* Direct pointer to the searchlist of the main object. */
300 struct r_scope_elem *_ns_main_searchlist;
301 /* This is zero at program start to signal that the global scope map is
302 allocated by rtld. Later it keeps the size of the map. It might be
303 reset if in _dl_close if the last global object is removed. */
304 size_t _ns_global_scope_alloc;
305 /* Search table for unique objects. */
306 struct unique_sym_table
307 {
308 __rtld_lock_define_recursive (, lock)
309 struct unique_sym
310 {
311 uint32_t hashval;
312 const char *name;
313 const ElfW(Sym) *sym;
314 const struct link_map *map;
315 } *entries;
316 size_t size;
317 size_t n_elements;
318 void (*free) (void *);
319 } _ns_unique_sym_table;
320 /* Keep track of changes to each namespace' list. */
321 struct r_debug _ns_debug;
322 } _dl_ns[DL_NNS];
323 /* One higher than index of last used namespace. */
324 EXTERN size_t _dl_nns;
325
326 /* During the program run we must not modify the global data of
327 loaded shared object simultanously in two threads. Therefore we
328 protect `_dl_open' and `_dl_close' in dl-close.c.
329
330 This must be a recursive lock since the initializer function of
331 the loaded object might as well require a call to this function.
332 At this time it is not anymore a problem to modify the tables. */
333 __rtld_lock_define_recursive (EXTERN, _dl_load_lock)
334 /* This lock is used to keep __dl_iterate_phdr from inspecting the
335 list of loaded objects while an object is added to or removed
336 from that list. */
337 __rtld_lock_define_recursive (EXTERN, _dl_load_write_lock)
338
339 /* Incremented whenever something may have been added to dl_loaded. */
340 EXTERN unsigned long long _dl_load_adds;
341
342 /* The object to be initialized first. */
343 EXTERN struct link_map *_dl_initfirst;
344
345#if HP_SMALL_TIMING_AVAIL
346 /* Start time on CPU clock. */
347 EXTERN hp_timing_t _dl_cpuclock_offset;
348#endif
349
350 /* Map of shared object to be profiled. */
351 EXTERN struct link_map *_dl_profile_map;
352
353 /* Counters for the number of relocations performed. */
354 EXTERN unsigned long int _dl_num_relocations;
355 EXTERN unsigned long int _dl_num_cache_relocations;
356
357 /* List of search directories. */
358 EXTERN struct r_search_path_elem *_dl_all_dirs;
359
360#ifdef _LIBC_REENTRANT
361 EXTERN void **(*_dl_error_catch_tsd) (void) __attribute__ ((const));
362#endif
363
364 /* Structure describing the dynamic linker itself. We need to
365 reserve memory for the data the audit libraries need. */
366 EXTERN struct link_map _dl_rtld_map;
367#ifdef SHARED
368 struct auditstate audit_data[DL_NNS];
369#endif
370
371#if defined SHARED && defined _LIBC_REENTRANT \
372 && defined __rtld_lock_default_lock_recursive
373 EXTERN void (*_dl_rtld_lock_recursive) (void *);
374 EXTERN void (*_dl_rtld_unlock_recursive) (void *);
375#endif
376
377 /* If loading a shared object requires that we make the stack executable
378 when it was not, we do it by calling this function.
379 It returns an errno code or zero on success. */
380 EXTERN int (*_dl_make_stack_executable_hook) (void **) internal_function;
381
382 /* Prevailing state of the stack, PF_X indicating it's executable. */
383 EXTERN ElfW(Word) _dl_stack_flags;
384
385 /* Flag signalling whether there are gaps in the module ID allocation. */
386 EXTERN bool _dl_tls_dtv_gaps;
387 /* Highest dtv index currently needed. */
388 EXTERN size_t _dl_tls_max_dtv_idx;
389 /* Information about the dtv slots. */
390 EXTERN struct dtv_slotinfo_list
391 {
392 size_t len;
393 struct dtv_slotinfo_list *next;
394 struct dtv_slotinfo
395 {
396 size_t gen;
397 struct link_map *map;
398 } slotinfo[0];
399 } *_dl_tls_dtv_slotinfo_list;
400 /* Number of modules in the static TLS block. */
401 EXTERN size_t _dl_tls_static_nelem;
402 /* Size of the static TLS block. */
403 EXTERN size_t _dl_tls_static_size;
404 /* Size actually allocated in the static TLS block. */
405 EXTERN size_t _dl_tls_static_used;
406 /* Alignment requirement of the static TLS block. */
407 EXTERN size_t _dl_tls_static_align;
408
409/* Number of additional entries in the slotinfo array of each slotinfo
410 list element. A large number makes it almost certain take we never
411 have to iterate beyond the first element in the slotinfo list. */
412#define TLS_SLOTINFO_SURPLUS (62)
413
414/* Number of additional slots in the dtv allocated. */
415#define DTV_SURPLUS (14)
416
417 /* Initial dtv of the main thread, not allocated with normal malloc. */
418 EXTERN void *_dl_initial_dtv;
419 /* Generation counter for the dtv. */
420 EXTERN size_t _dl_tls_generation;
421
422 EXTERN void (*_dl_init_static_tls) (struct link_map *);
423
424 EXTERN void (*_dl_wait_lookup_done) (void);
425
426 /* Scopes to free after next THREAD_GSCOPE_WAIT (). */
427 EXTERN struct dl_scope_free_list
428 {
429 size_t count;
430 void *list[50];
431 } *_dl_scope_free_list;
432#ifdef SHARED
433};
434# define __rtld_global_attribute__
435# if IS_IN (rtld)
436# ifdef HAVE_SDATA_SECTION
437# define __rtld_local_attribute__ \
438 __attribute__ ((visibility ("hidden"), section (".sdata")))
439# undef __rtld_global_attribute__
440# define __rtld_global_attribute__ __attribute__ ((section (".sdata")))
441# else
442# define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
443# endif
444extern struct rtld_global _rtld_local __rtld_local_attribute__;
445# undef __rtld_local_attribute__
446# endif
447extern struct rtld_global _rtld_global __rtld_global_attribute__;
448# undef __rtld_global_attribute__
449#endif
450
451#ifndef SHARED
452# define GLRO(name) _##name
453#else
454# if IS_IN (rtld)
455# define GLRO(name) _rtld_local_ro._##name
456# else
457# define GLRO(name) _rtld_global_ro._##name
458# endif
459struct rtld_global_ro
460{
461#endif
462
463 /* If nonzero the appropriate debug information is printed. */
464 EXTERN int _dl_debug_mask;
465#define DL_DEBUG_LIBS (1 << 0)
466#define DL_DEBUG_IMPCALLS (1 << 1)
467#define DL_DEBUG_BINDINGS (1 << 2)
468#define DL_DEBUG_SYMBOLS (1 << 3)
469#define DL_DEBUG_VERSIONS (1 << 4)
470#define DL_DEBUG_RELOC (1 << 5)
471#define DL_DEBUG_FILES (1 << 6)
472#define DL_DEBUG_STATISTICS (1 << 7)
473#define DL_DEBUG_UNUSED (1 << 8)
474#define DL_DEBUG_SCOPES (1 << 9)
475/* These two are used only internally. */
476#define DL_DEBUG_HELP (1 << 10)
477#define DL_DEBUG_PRELINK (1 << 11)
478
479 /* OS version. */
480 EXTERN unsigned int _dl_osversion;
481 /* Platform name. */
482 EXTERN const char *_dl_platform;
483 EXTERN size_t _dl_platformlen;
484
485 /* Cached value of `getpagesize ()'. */
486 EXTERN size_t _dl_pagesize;
487
488 /* Do we read from ld.so.cache? */
489 EXTERN int _dl_inhibit_cache;
490
491 /* Copy of the content of `_dl_main_searchlist' at startup time. */
492 EXTERN struct r_scope_elem _dl_initial_searchlist;
493
494 /* CLK_TCK as reported by the kernel. */
495 EXTERN int _dl_clktck;
496
497 /* If nonzero print warnings messages. */
498 EXTERN int _dl_verbose;
499
500 /* File descriptor to write debug messages to. */
501 EXTERN int _dl_debug_fd;
502
503 /* Do we do lazy relocations? */
504 EXTERN int _dl_lazy;
505
506 /* Nonzero if runtime lookups should not update the .got/.plt. */
507 EXTERN int _dl_bind_not;
508
509 /* Nonzero if references should be treated as weak during runtime
510 linking. */
511 EXTERN int _dl_dynamic_weak;
512
513 /* Default floating-point control word. */
514 EXTERN fpu_control_t _dl_fpu_control;
515
516 /* Expected cache ID. */
517 EXTERN int _dl_correct_cache_id;
518
519 /* Mask for hardware capabilities that are available. */
520 EXTERN uint64_t _dl_hwcap;
521
522 /* Mask for important hardware capabilities we honour. */
523 EXTERN uint64_t _dl_hwcap_mask;
524
525#ifdef HAVE_AUX_VECTOR
526 /* Pointer to the auxv list supplied to the program at startup. */
527 EXTERN ElfW(auxv_t) *_dl_auxv;
528#endif
529
530 /* Get architecture specific definitions. */
531#define PROCINFO_DECL
532#ifndef PROCINFO_CLASS
533# define PROCINFO_CLASS EXTERN
534#endif
535#include <dl-procinfo.c>
536
537 /* Names of shared object for which the RPATH should be ignored. */
538 EXTERN const char *_dl_inhibit_rpath;
539
540 /* Location of the binary. */
541 EXTERN const char *_dl_origin_path;
542
543 /* -1 if the dynamic linker should honor library load bias,
544 0 if not, -2 use the default (honor biases for normal
545 binaries, don't honor for PIEs). */
546 EXTERN ElfW(Addr) _dl_use_load_bias;
547
548 /* Name of the shared object to be profiled (if any). */
549 EXTERN const char *_dl_profile;
550 /* Filename of the output file. */
551 EXTERN const char *_dl_profile_output;
552 /* Name of the object we want to trace the prelinking. */
553 EXTERN const char *_dl_trace_prelink;
554 /* Map of shared object to be prelink traced. */
555 EXTERN struct link_map *_dl_trace_prelink_map;
556
557 /* All search directories defined at startup. */
558 EXTERN struct r_search_path_elem *_dl_init_all_dirs;
559
560#ifdef NEED_DL_SYSINFO
561 /* Syscall handling improvements. This is very specific to x86. */
562 EXTERN uintptr_t _dl_sysinfo;
563#endif
564
565#ifdef NEED_DL_SYSINFO_DSO
566 /* The vsyscall page is a virtual DSO pre-mapped by the kernel.
567 This points to its ELF header. */
568 EXTERN const ElfW(Ehdr) *_dl_sysinfo_dso;
569
570 /* At startup time we set up the normal DSO data structure for it,
571 and this points to it. */
572 EXTERN struct link_map *_dl_sysinfo_map;
573#endif
574
575 /* Mask for more hardware capabilities that are available on some
576 platforms. */
577 EXTERN uint64_t _dl_hwcap2;
578
579#ifdef SHARED
580 /* We add a function table to _rtld_global which is then used to
581 call the function instead of going through the PLT. The result
582 is that we can avoid exporting the functions and we do not jump
583 PLT relocations in libc.so. */
584 void (*_dl_debug_printf) (const char *, ...)
585 __attribute__ ((__format__ (__printf__, 1, 2)));
586 int (internal_function *_dl_catch_error) (const char **, const char **,
587 bool *, void (*) (void *), void *);
588 void (internal_function *_dl_signal_error) (int, const char *, const char *,
589 const char *);
590 void (*_dl_mcount) (ElfW(Addr) frompc, ElfW(Addr) selfpc);
591 lookup_t (internal_function *_dl_lookup_symbol_x) (const char *,
592 struct link_map *,
593 const ElfW(Sym) **,
594 struct r_scope_elem *[],
595 const struct r_found_version *,
596 int, int,
597 struct link_map *);
598 int (*_dl_check_caller) (const void *, enum allowmask);
599 void *(*_dl_open) (const char *file, int mode, const void *caller_dlopen,
600 Lmid_t nsid, int argc, char *argv[], char *env[]);
601 void (*_dl_close) (void *map);
602 void *(*_dl_tls_get_addr_soft) (struct link_map *);
603#ifdef HAVE_DL_DISCOVER_OSVERSION
604 int (*_dl_discover_osversion) (void);
605#endif
606
607 /* List of auditing interfaces. */
608 struct audit_ifaces *_dl_audit;
609 unsigned int _dl_naudit;
610};
611# define __rtld_global_attribute__
612# if IS_IN (rtld)
613# define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
614extern struct rtld_global_ro _rtld_local_ro
615 attribute_relro __rtld_local_attribute__;
616extern struct rtld_global_ro _rtld_global_ro
617 attribute_relro __rtld_global_attribute__;
618# undef __rtld_local_attribute__
619# else
620/* We cheat a bit here. We declare the variable as as const even
621 though it is at startup. */
622extern const struct rtld_global_ro _rtld_global_ro
623 attribute_relro __rtld_global_attribute__;
624# endif
625# undef __rtld_global_attribute__
626#endif
627#undef EXTERN
628
629#ifndef SHARED
630/* dl-support.c defines these and initializes them early on. */
631extern const ElfW(Phdr) *_dl_phdr;
632extern size_t _dl_phnum;
633#endif
634
635#if IS_IN (rtld)
636/* This is the initial value of GL(dl_error_catch_tsd).
637 A non-TLS libpthread will change it. */
638extern void **_dl_initial_error_catch_tsd (void) __attribute__ ((const))
639 attribute_hidden;
640#endif
641
642/* This is the initial value of GL(dl_make_stack_executable_hook).
643 A threads library can change it. */
644extern int _dl_make_stack_executable (void **stack_endp) internal_function;
645rtld_hidden_proto (_dl_make_stack_executable)
646
647/* Variable pointing to the end of the stack (or close to it). This value
648 must be constant over the runtime of the application. Some programs
649 might use the variable which results in copy relocations on some
650 platforms. But this does not matter, ld.so can always use the local
651 copy. */
652extern void *__libc_stack_end
653#ifndef LIBC_STACK_END_NOT_RELRO
654 attribute_relro
655#endif
656 ;
657rtld_hidden_proto (__libc_stack_end)
658
659/* Parameters passed to the dynamic linker. */
660extern int _dl_argc attribute_hidden attribute_relro;
661extern char **_dl_argv
662#ifndef DL_ARGV_NOT_RELRO
663 attribute_relro
664#endif
665 ;
666rtld_hidden_proto (_dl_argv)
667#if IS_IN (rtld)
668extern unsigned int _dl_skip_args attribute_hidden
669# ifndef DL_ARGV_NOT_RELRO
670 attribute_relro
671# endif
672 ;
673extern unsigned int _dl_skip_args_internal attribute_hidden
674# ifndef DL_ARGV_NOT_RELRO
675 attribute_relro
676# endif
677 ;
678#endif
679#define rtld_progname _dl_argv[0]
680
681/* Flag set at startup and cleared when the last initializer has run. */
682extern int _dl_starting_up;
683weak_extern (_dl_starting_up)
684rtld_hidden_proto (_dl_starting_up)
685
686/* Random data provided by the kernel. */
687extern void *_dl_random attribute_hidden attribute_relro;
688
689/* OS-dependent function to open the zero-fill device. */
690extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */
691
692
693/* Write message on the debug file descriptor. The parameters are
694 interpreted as for a `printf' call. All the lines start with a
695 tag showing the PID. */
696extern void _dl_debug_printf (const char *fmt, ...)
697 __attribute__ ((__format__ (__printf__, 1, 2))) attribute_hidden;
698
699/* Write message on the debug file descriptor. The parameters are
700 interpreted as for a `printf' call. All the lines buf the first
701 start with a tag showing the PID. */
702extern void _dl_debug_printf_c (const char *fmt, ...)
703 __attribute__ ((__format__ (__printf__, 1, 2))) attribute_hidden;
704
705
706/* Write a message on the specified descriptor FD. The parameters are
707 interpreted as for a `printf' call. */
708extern void _dl_dprintf (int fd, const char *fmt, ...)
709 __attribute__ ((__format__ (__printf__, 2, 3)))
710 attribute_hidden;
711
712/* Write a message on the specified descriptor standard output. The
713 parameters are interpreted as for a `printf' call. */
714#define _dl_printf(fmt, args...) \
715 _dl_dprintf (STDOUT_FILENO, fmt, ##args)
716
717/* Write a message on the specified descriptor standard error. The
718 parameters are interpreted as for a `printf' call. */
719#define _dl_error_printf(fmt, args...) \
720 _dl_dprintf (STDERR_FILENO, fmt, ##args)
721
722/* Write a message on the specified descriptor standard error and exit
723 the program. The parameters are interpreted as for a `printf' call. */
724#define _dl_fatal_printf(fmt, args...) \
725 do \
726 { \
727 _dl_dprintf (STDERR_FILENO, fmt, ##args); \
728 _exit (127); \
729 } \
730 while (1)
731
732
733/* This function is called by all the internal dynamic linker functions
734 when they encounter an error. ERRCODE is either an `errno' code or
735 zero; OBJECT is the name of the problematical shared object, or null if
736 it is a general problem; ERRSTRING is a string describing the specific
737 problem. */
738extern void _dl_signal_error (int errcode, const char *object,
739 const char *occurred, const char *errstring)
740 internal_function __attribute__ ((__noreturn__)) attribute_hidden;
741
742/* Like _dl_signal_error, but may return when called in the context of
743 _dl_receive_error. */
744extern void _dl_signal_cerror (int errcode, const char *object,
745 const char *occation, const char *errstring)
746 internal_function attribute_hidden;
747
748/* Call OPERATE, receiving errors from `dl_signal_cerror'. Unlike
749 `_dl_catch_error' the operation is resumed after the OPERATE
750 function returns.
751 ARGS is passed as argument to OPERATE. */
752extern void _dl_receive_error (receiver_fct fct, void (*operate) (void *),
753 void *args)
754 internal_function attribute_hidden;
755
756/* Call OPERATE, catching errors from `dl_signal_error'. If there is no
757 error, *ERRSTRING is set to null. If there is an error, *ERRSTRING is
758 set to a string constructed from the strings passed to _dl_signal_error,
759 and the error code passed is the return value and *OBJNAME is set to
760 the object name which experienced the problems. ERRSTRING if nonzero
761 points to a malloc'ed string which the caller has to free after use.
762 ARGS is passed as argument to OPERATE. MALLOCEDP is set to true only
763 if the returned string is allocated using the libc's malloc. */
764extern int _dl_catch_error (const char **objname, const char **errstring,
765 bool *mallocedp, void (*operate) (void *),
766 void *args)
767 internal_function attribute_hidden;
768
769/* Open the shared object NAME and map in its segments.
770 LOADER's DT_RPATH is used in searching for NAME.
771 If the object is already opened, returns its existing map. */
772extern struct link_map *_dl_map_object (struct link_map *loader,
773 const char *name,
774 int type, int trace_mode, int mode,
775 Lmid_t nsid)
776 internal_function attribute_hidden;
777
778/* Call _dl_map_object on the dependencies of MAP, and set up
779 MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously
780 loaded objects that will be inserted into MAP->l_searchlist after MAP
781 but before its dependencies. */
782extern void _dl_map_object_deps (struct link_map *map,
783 struct link_map **preloads,
784 unsigned int npreloads, int trace_mode,
785 int open_mode)
786 internal_function attribute_hidden;
787
788/* Cache the locations of MAP's hash table. */
789extern void _dl_setup_hash (struct link_map *map)
790 internal_function attribute_hidden;
791
792
793/* Collect the directories in the search path for LOADER's dependencies.
794 The data structure is defined in <dlfcn.h>. If COUNTING is true,
795 SI->dls_cnt and SI->dls_size are set; if false, those must be as set
796 by a previous call with COUNTING set, and SI must point to SI->dls_size
797 bytes to be used in filling in the result. */
798extern void _dl_rtld_di_serinfo (struct link_map *loader,
799 Dl_serinfo *si, bool counting)
800 internal_function;
801
802
803/* Search loaded objects' symbol tables for a definition of the symbol
804 referred to by UNDEF. *SYM is the symbol table entry containing the
805 reference; it is replaced with the defining symbol, and the base load
806 address of the defining object is returned. SYMBOL_SCOPE is a
807 null-terminated list of object scopes to search; each object's
808 l_searchlist (i.e. the segment of the dependency tree starting at that
809 object) is searched in turn. REFERENCE_NAME should name the object
810 containing the reference; it is used in error messages.
811 TYPE_CLASS describes the type of symbol we are looking for. */
812enum
813 {
814 /* If necessary add dependency between user and provider object. */
815 DL_LOOKUP_ADD_DEPENDENCY = 1,
816 /* Return most recent version instead of default version for
817 unversioned lookup. */
818 DL_LOOKUP_RETURN_NEWEST = 2,
819 /* Set if dl_lookup* called with GSCOPE lock held. */
820 DL_LOOKUP_GSCOPE_LOCK = 4,
821 };
822
823/* Lookup versioned symbol. */
824extern lookup_t _dl_lookup_symbol_x (const char *undef,
825 struct link_map *undef_map,
826 const ElfW(Sym) **sym,
827 struct r_scope_elem *symbol_scope[],
828 const struct r_found_version *version,
829 int type_class, int flags,
830 struct link_map *skip_map)
831 internal_function attribute_hidden;
832
833
834/* Look up symbol NAME in MAP's scope and return its run-time address. */
835extern ElfW(Addr) _dl_symbol_value (struct link_map *map, const char *name)
836 internal_function;
837
838/* Add the new link_map NEW to the end of the namespace list. */
839extern void _dl_add_to_namespace_list (struct link_map *new, Lmid_t nsid)
840 internal_function attribute_hidden;
841
842/* Allocate a `struct link_map' for a new object being loaded. */
843extern struct link_map *_dl_new_object (char *realname, const char *libname,
844 int type, struct link_map *loader,
845 int mode, Lmid_t nsid)
846 internal_function attribute_hidden;
847
848/* Relocate the given object (if it hasn't already been).
849 SCOPE is passed to _dl_lookup_symbol in symbol lookups.
850 If RTLD_LAZY is set in RELOC-MODE, don't relocate its PLT. */
851extern void _dl_relocate_object (struct link_map *map,
852 struct r_scope_elem *scope[],
853 int reloc_mode, int consider_profiling)
854 attribute_hidden;
855
856/* Protect PT_GNU_RELRO area. */
857extern void _dl_protect_relro (struct link_map *map)
858 internal_function attribute_hidden;
859
860/* Call _dl_signal_error with a message about an unhandled reloc type.
861 TYPE is the result of ELFW(R_TYPE) (r_info), i.e. an R_<CPU>_* value.
862 PLT is nonzero if this was a PLT reloc; it just affects the message. */
863extern void _dl_reloc_bad_type (struct link_map *map,
864 unsigned int type, int plt)
865 internal_function attribute_hidden __attribute__ ((__noreturn__));
866
867/* Resolve conflicts if prelinking. */
868extern void _dl_resolve_conflicts (struct link_map *l,
869 ElfW(Rela) *conflict,
870 ElfW(Rela) *conflictend)
871 attribute_hidden;
872
873/* Check the version dependencies of all objects available through
874 MAP. If VERBOSE print some more diagnostics. */
875extern int _dl_check_all_versions (struct link_map *map, int verbose,
876 int trace_mode)
877 internal_function attribute_hidden;
878
879/* Check the version dependencies for MAP. If VERBOSE print some more
880 diagnostics. */
881extern int _dl_check_map_versions (struct link_map *map, int verbose,
882 int trace_mode)
883 internal_function attribute_hidden;
884
885/* Initialize the object in SCOPE by calling the constructors with
886 ARGC, ARGV, and ENV as the parameters. */
887extern void _dl_init (struct link_map *main_map, int argc, char **argv,
888 char **env) internal_function attribute_hidden;
889
890/* Call the finalizer functions of all shared objects whose
891 initializer functions have completed. */
892extern void _dl_fini (void) internal_function;
893
894/* Sort array MAPS according to dependencies of the contained objects. */
895extern void _dl_sort_fini (struct link_map **maps, size_t nmaps, char *used,
896 Lmid_t ns)
897 internal_function attribute_hidden;
898
899/* The dynamic linker calls this function before and having changing
900 any shared object mappings. The `r_state' member of `struct r_debug'
901 says what change is taking place. This function's address is
902 the value of the `r_brk' member. */
903extern void _dl_debug_state (void);
904rtld_hidden_proto (_dl_debug_state)
905
906/* Initialize `struct r_debug' if it has not already been done. The
907 argument is the run-time load address of the dynamic linker, to be put
908 in the `r_ldbase' member. Returns the address of the structure. */
909extern struct r_debug *_dl_debug_initialize (ElfW(Addr) ldbase, Lmid_t ns)
910 internal_function attribute_hidden;
911
912/* Initialize the basic data structure for the search paths. */
913extern void _dl_init_paths (const char *library_path)
914 internal_function attribute_hidden;
915
916/* Gather the information needed to install the profiling tables and start
917 the timers. */
918extern void _dl_start_profile (void) internal_function attribute_hidden;
919
920/* The actual functions used to keep book on the calls. */
921extern void _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc);
922rtld_hidden_proto (_dl_mcount)
923
924/* This function is simply a wrapper around the _dl_mcount function
925 which does not require a FROMPC parameter since this is the
926 calling function. */
927extern void _dl_mcount_wrapper (void *selfpc);
928
929/* Show the members of the auxiliary array passed up from the kernel. */
930extern void _dl_show_auxv (void)
931 internal_function attribute_hidden;
932
933/* Return all environment variables starting with `LD_', one after the
934 other. */
935extern char *_dl_next_ld_env_entry (char ***position)
936 internal_function attribute_hidden;
937
938/* Return an array with the names of the important hardware capabilities. */
939extern const struct r_strlenpair *_dl_important_hwcaps (const char *platform,
940 size_t paltform_len,
941 size_t *sz,
942 size_t *max_capstrlen)
943 internal_function attribute_hidden;
944
945/* Look up NAME in ld.so.cache and return the file name stored there,
946 or null if none is found. Caller must free returned string. */
947extern char *_dl_load_cache_lookup (const char *name)
948 internal_function attribute_hidden;
949
950/* If the system does not support MAP_COPY we cannot leave the file open
951 all the time since this would create problems when the file is replaced.
952 Therefore we provide this function to close the file and open it again
953 once needed. */
954extern void _dl_unload_cache (void) attribute_hidden;
955
956/* System-dependent function to read a file's whole contents in the
957 most convenient manner available. *SIZEP gets the size of the
958 file. On error MAP_FAILED is returned. */
959extern void *_dl_sysdep_read_whole_file (const char *file, size_t *sizep,
960 int prot)
961 internal_function attribute_hidden;
962
963/* System-specific function to do initial startup for the dynamic linker.
964 After this, file access calls and getenv must work. This is responsible
965 for setting __libc_enable_secure if we need to be secure (e.g. setuid),
966 and for setting _dl_argc and _dl_argv, and then calling _dl_main. */
967extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
968 void (*dl_main) (const ElfW(Phdr) *phdr,
969 ElfW(Word) phnum,
970 ElfW(Addr) *user_entry,
971 ElfW(auxv_t) *auxv))
972 attribute_hidden;
973
974extern void _dl_sysdep_start_cleanup (void)
975 internal_function attribute_hidden;
976
977
978/* Determine next available module ID. */
979extern size_t _dl_next_tls_modid (void) internal_function attribute_hidden;
980
981/* Count the modules with TLS segments. */
982extern size_t _dl_count_modids (void) internal_function attribute_hidden;
983
984/* Calculate offset of the TLS blocks in the static TLS block. */
985extern void _dl_determine_tlsoffset (void) internal_function attribute_hidden;
986
987/* Set up the data structures for TLS, when they were not set up at startup.
988 Returns nonzero on malloc failure.
989 This is called from _dl_map_object_from_fd or by libpthread. */
990extern int _dl_tls_setup (void) internal_function;
991rtld_hidden_proto (_dl_tls_setup)
992
993/* Allocate memory for static TLS block (unless MEM is nonzero) and dtv. */
994extern void *_dl_allocate_tls (void *mem) internal_function;
995rtld_hidden_proto (_dl_allocate_tls)
996
997/* Get size and alignment requirements of the static TLS block. */
998extern void _dl_get_tls_static_info (size_t *sizep, size_t *alignp)
999 internal_function;
1000
1001extern void _dl_allocate_static_tls (struct link_map *map)
1002 internal_function attribute_hidden;
1003
1004/* These are internal entry points to the two halves of _dl_allocate_tls,
1005 only used within rtld.c itself at startup time. */
1006extern void *_dl_allocate_tls_storage (void)
1007 internal_function attribute_hidden;
1008extern void *_dl_allocate_tls_init (void *) internal_function;
1009rtld_hidden_proto (_dl_allocate_tls_init)
1010
1011/* Deallocate memory allocated with _dl_allocate_tls. */
1012extern void _dl_deallocate_tls (void *tcb, bool dealloc_tcb) internal_function;
1013rtld_hidden_proto (_dl_deallocate_tls)
1014
1015extern void _dl_nothread_init_static_tls (struct link_map *) attribute_hidden;
1016
1017/* Find origin of the executable. */
1018extern const char *_dl_get_origin (void) attribute_hidden;
1019
1020/* Count DSTs. */
1021extern size_t _dl_dst_count (const char *name, int is_path) attribute_hidden;
1022
1023/* Substitute DST values. */
1024extern char *_dl_dst_substitute (struct link_map *l, const char *name,
1025 char *result, int is_path) attribute_hidden;
1026
1027/* Check validity of the caller. */
1028extern int _dl_check_caller (const void *caller, enum allowmask mask)
1029 attribute_hidden;
1030
1031/* Open the shared object NAME, relocate it, and run its initializer if it
1032 hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If
1033 the object is already opened, returns its existing map. */
1034extern void *_dl_open (const char *name, int mode, const void *caller,
1035 Lmid_t nsid, int argc, char *argv[], char *env[])
1036 attribute_hidden;
1037
1038/* Free or queue for freeing scope OLD. If other threads might be
1039 in the middle of _dl_fixup, _dl_profile_fixup or dl*sym using the
1040 old scope, OLD can't be freed until no thread is using it. */
1041extern int _dl_scope_free (void *) attribute_hidden;
1042
1043/* Add module to slot information data. */
1044extern void _dl_add_to_slotinfo (struct link_map *l) attribute_hidden;
1045
1046/* Update slot information data for at least the generation of the
1047 module with the given index. */
1048extern struct link_map *_dl_update_slotinfo (unsigned long int req_modid)
1049 attribute_hidden;
1050
1051/* Look up the module's TLS block as for __tls_get_addr,
1052 but never touch anything. Return null if it's not allocated yet. */
1053extern void *_dl_tls_get_addr_soft (struct link_map *l) attribute_hidden;
1054
1055extern int _dl_addr_inside_object (struct link_map *l, const ElfW(Addr) addr)
1056 internal_function attribute_hidden;
1057
1058/* Show show of an object. */
1059extern void _dl_show_scope (struct link_map *new, int from)
1060 attribute_hidden;
1061
1062extern struct link_map *_dl_find_dso_for_object (const ElfW(Addr) addr)
1063 internal_function;
1064rtld_hidden_proto (_dl_find_dso_for_object)
1065
1066/* Initialization which is normally done by the dynamic linker. */
1067extern void _dl_non_dynamic_init (void) internal_function;
1068
1069/* Used by static binaries to check the auxiliary vector. */
1070extern void _dl_aux_init (ElfW(auxv_t) *av) internal_function;
1071
1072
1073__END_DECLS
1074
1075#endif /* ldsodefs.h */
1076