1/* Run-time dynamic linker data structures for loaded ELF shared objects.
2 Copyright (C) 1995-2017 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/* A stripped down strtoul-like implementation. */
258uint64_t internal_function _dl_strtoul (const char *, char **)
259 internal_function attribute_hidden;
260
261/* Function used as argument for `_dl_receive_error' function. The
262 arguments are the error code, error string, and the objname the
263 error occurred in. */
264typedef void (*receiver_fct) (int, const char *, const char *);
265
266/* Internal functions of the run-time dynamic linker.
267 These can be accessed if you link again the dynamic linker
268 as a shared library, as in `-lld' or `/lib/ld.so' explicitly;
269 but are not normally of interest to user programs.
270
271 The `-ldl' library functions in <dlfcn.h> provide a simple
272 user interface to run-time dynamic linking. */
273
274
275#ifndef SHARED
276# define EXTERN extern
277# define GL(name) _##name
278#else
279# define EXTERN
280# if IS_IN (rtld)
281# define GL(name) _rtld_local._##name
282# else
283# define GL(name) _rtld_global._##name
284# endif
285struct rtld_global
286{
287#endif
288 /* Don't change the order of the following elements. 'dl_loaded'
289 must remain the first element. Forever. */
290
291/* Non-shared code has no support for multiple namespaces. */
292#ifdef SHARED
293# define DL_NNS 16
294#else
295# define DL_NNS 1
296#endif
297 EXTERN struct link_namespaces
298 {
299 /* A pointer to the map for the main map. */
300 struct link_map *_ns_loaded;
301 /* Number of object in the _dl_loaded list. */
302 unsigned int _ns_nloaded;
303 /* Direct pointer to the searchlist of the main object. */
304 struct r_scope_elem *_ns_main_searchlist;
305 /* This is zero at program start to signal that the global scope map is
306 allocated by rtld. Later it keeps the size of the map. It might be
307 reset if in _dl_close if the last global object is removed. */
308 size_t _ns_global_scope_alloc;
309 /* Search table for unique objects. */
310 struct unique_sym_table
311 {
312 __rtld_lock_define_recursive (, lock)
313 struct unique_sym
314 {
315 uint32_t hashval;
316 const char *name;
317 const ElfW(Sym) *sym;
318 const struct link_map *map;
319 } *entries;
320 size_t size;
321 size_t n_elements;
322 void (*free) (void *);
323 } _ns_unique_sym_table;
324 /* Keep track of changes to each namespace' list. */
325 struct r_debug _ns_debug;
326 } _dl_ns[DL_NNS];
327 /* One higher than index of last used namespace. */
328 EXTERN size_t _dl_nns;
329
330 /* During the program run we must not modify the global data of
331 loaded shared object simultanously in two threads. Therefore we
332 protect `_dl_open' and `_dl_close' in dl-close.c.
333
334 This must be a recursive lock since the initializer function of
335 the loaded object might as well require a call to this function.
336 At this time it is not anymore a problem to modify the tables. */
337 __rtld_lock_define_recursive (EXTERN, _dl_load_lock)
338 /* This lock is used to keep __dl_iterate_phdr from inspecting the
339 list of loaded objects while an object is added to or removed
340 from that list. */
341 __rtld_lock_define_recursive (EXTERN, _dl_load_write_lock)
342
343 /* Incremented whenever something may have been added to dl_loaded. */
344 EXTERN unsigned long long _dl_load_adds;
345
346 /* The object to be initialized first. */
347 EXTERN struct link_map *_dl_initfirst;
348
349#if HP_SMALL_TIMING_AVAIL
350 /* Start time on CPU clock. */
351 EXTERN hp_timing_t _dl_cpuclock_offset;
352#endif
353
354 /* Map of shared object to be profiled. */
355 EXTERN struct link_map *_dl_profile_map;
356
357 /* Counters for the number of relocations performed. */
358 EXTERN unsigned long int _dl_num_relocations;
359 EXTERN unsigned long int _dl_num_cache_relocations;
360
361 /* List of search directories. */
362 EXTERN struct r_search_path_elem *_dl_all_dirs;
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#if !HAVE_TUNABLES
523 /* Mask for important hardware capabilities we honour. */
524 EXTERN uint64_t _dl_hwcap_mask;
525#endif
526
527#ifdef HAVE_AUX_VECTOR
528 /* Pointer to the auxv list supplied to the program at startup. */
529 EXTERN ElfW(auxv_t) *_dl_auxv;
530#endif
531
532 /* Get architecture specific definitions. */
533#define PROCINFO_DECL
534#ifndef PROCINFO_CLASS
535# define PROCINFO_CLASS EXTERN
536#endif
537#include <dl-procinfo.c>
538
539 /* Names of shared object for which the RPATH should be ignored. */
540 EXTERN const char *_dl_inhibit_rpath;
541
542 /* Location of the binary. */
543 EXTERN const char *_dl_origin_path;
544
545 /* -1 if the dynamic linker should honor library load bias,
546 0 if not, -2 use the default (honor biases for normal
547 binaries, don't honor for PIEs). */
548 EXTERN ElfW(Addr) _dl_use_load_bias;
549
550 /* Name of the shared object to be profiled (if any). */
551 EXTERN const char *_dl_profile;
552 /* Filename of the output file. */
553 EXTERN const char *_dl_profile_output;
554 /* Name of the object we want to trace the prelinking. */
555 EXTERN const char *_dl_trace_prelink;
556 /* Map of shared object to be prelink traced. */
557 EXTERN struct link_map *_dl_trace_prelink_map;
558
559 /* All search directories defined at startup. */
560 EXTERN struct r_search_path_elem *_dl_init_all_dirs;
561
562#ifdef NEED_DL_SYSINFO
563 /* Syscall handling improvements. This is very specific to x86. */
564 EXTERN uintptr_t _dl_sysinfo;
565#endif
566
567#ifdef NEED_DL_SYSINFO_DSO
568 /* The vsyscall page is a virtual DSO pre-mapped by the kernel.
569 This points to its ELF header. */
570 EXTERN const ElfW(Ehdr) *_dl_sysinfo_dso;
571
572 /* At startup time we set up the normal DSO data structure for it,
573 and this points to it. */
574 EXTERN struct link_map *_dl_sysinfo_map;
575#endif
576
577 /* Mask for more hardware capabilities that are available on some
578 platforms. */
579 EXTERN uint64_t _dl_hwcap2;
580
581#ifdef SHARED
582 /* We add a function table to _rtld_global which is then used to
583 call the function instead of going through the PLT. The result
584 is that we can avoid exporting the functions and we do not jump
585 PLT relocations in libc.so. */
586 void (*_dl_debug_printf) (const char *, ...)
587 __attribute__ ((__format__ (__printf__, 1, 2)));
588 void (*_dl_mcount) (ElfW(Addr) frompc, ElfW(Addr) selfpc);
589 lookup_t (internal_function *_dl_lookup_symbol_x) (const char *,
590 struct link_map *,
591 const ElfW(Sym) **,
592 struct r_scope_elem *[],
593 const struct r_found_version *,
594 int, int,
595 struct link_map *);
596 int (*_dl_check_caller) (const void *, enum allowmask);
597 void *(*_dl_open) (const char *file, int mode, const void *caller_dlopen,
598 Lmid_t nsid, int argc, char *argv[], char *env[]);
599 void (*_dl_close) (void *map);
600 void *(*_dl_tls_get_addr_soft) (struct link_map *);
601#ifdef HAVE_DL_DISCOVER_OSVERSION
602 int (*_dl_discover_osversion) (void);
603#endif
604
605 /* List of auditing interfaces. */
606 struct audit_ifaces *_dl_audit;
607 unsigned int _dl_naudit;
608};
609# define __rtld_global_attribute__
610# if IS_IN (rtld)
611# define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
612extern struct rtld_global_ro _rtld_local_ro
613 attribute_relro __rtld_local_attribute__;
614extern struct rtld_global_ro _rtld_global_ro
615 attribute_relro __rtld_global_attribute__;
616# undef __rtld_local_attribute__
617# else
618/* We cheat a bit here. We declare the variable as as const even
619 though it is at startup. */
620extern const struct rtld_global_ro _rtld_global_ro
621 attribute_relro __rtld_global_attribute__;
622# endif
623# undef __rtld_global_attribute__
624#endif
625#undef EXTERN
626
627#ifndef SHARED
628/* dl-support.c defines these and initializes them early on. */
629extern const ElfW(Phdr) *_dl_phdr;
630extern size_t _dl_phnum;
631#endif
632
633/* This is the initial value of GL(dl_make_stack_executable_hook).
634 A threads library can change it. */
635extern int _dl_make_stack_executable (void **stack_endp) internal_function;
636rtld_hidden_proto (_dl_make_stack_executable)
637
638/* Variable pointing to the end of the stack (or close to it). This value
639 must be constant over the runtime of the application. Some programs
640 might use the variable which results in copy relocations on some
641 platforms. But this does not matter, ld.so can always use the local
642 copy. */
643extern void *__libc_stack_end
644#ifndef LIBC_STACK_END_NOT_RELRO
645 attribute_relro
646#endif
647 ;
648rtld_hidden_proto (__libc_stack_end)
649
650/* Parameters passed to the dynamic linker. */
651extern int _dl_argc attribute_hidden attribute_relro;
652extern char **_dl_argv
653#ifndef DL_ARGV_NOT_RELRO
654 attribute_relro
655#endif
656 ;
657rtld_hidden_proto (_dl_argv)
658#if IS_IN (rtld)
659extern unsigned int _dl_skip_args attribute_hidden
660# ifndef DL_ARGV_NOT_RELRO
661 attribute_relro
662# endif
663 ;
664extern unsigned int _dl_skip_args_internal attribute_hidden
665# ifndef DL_ARGV_NOT_RELRO
666 attribute_relro
667# endif
668 ;
669#endif
670#define rtld_progname _dl_argv[0]
671
672/* Flag set at startup and cleared when the last initializer has run. */
673extern int _dl_starting_up;
674weak_extern (_dl_starting_up)
675rtld_hidden_proto (_dl_starting_up)
676
677/* Random data provided by the kernel. */
678extern void *_dl_random attribute_hidden attribute_relro;
679
680/* OS-dependent function to open the zero-fill device. */
681extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */
682
683
684/* Write message on the debug file descriptor. The parameters are
685 interpreted as for a `printf' call. All the lines start with a
686 tag showing the PID. */
687extern void _dl_debug_printf (const char *fmt, ...)
688 __attribute__ ((__format__ (__printf__, 1, 2))) attribute_hidden;
689
690/* Write message on the debug file descriptor. The parameters are
691 interpreted as for a `printf' call. All the lines buf the first
692 start with a tag showing the PID. */
693extern void _dl_debug_printf_c (const char *fmt, ...)
694 __attribute__ ((__format__ (__printf__, 1, 2))) attribute_hidden;
695
696
697/* Write a message on the specified descriptor FD. The parameters are
698 interpreted as for a `printf' call. */
699#if IS_IN (rtld) || !defined (SHARED)
700extern void _dl_dprintf (int fd, const char *fmt, ...)
701 __attribute__ ((__format__ (__printf__, 2, 3)))
702 attribute_hidden;
703#else
704__attribute__ ((always_inline, __format__ (__printf__, 2, 3)))
705static inline void
706_dl_dprintf (int fd, const char *fmt, ...)
707{
708 /* Use local declaration to avoid includign <stdio.h>. */
709 extern int __dprintf(int fd, const char *format, ...) attribute_hidden;
710 __dprintf (fd, fmt, __builtin_va_arg_pack ());
711}
712#endif
713
714/* Write a message on the specified descriptor standard output. The
715 parameters are interpreted as for a `printf' call. */
716#define _dl_printf(fmt, args...) \
717 _dl_dprintf (STDOUT_FILENO, fmt, ##args)
718
719/* Write a message on the specified descriptor standard error. The
720 parameters are interpreted as for a `printf' call. */
721#define _dl_error_printf(fmt, args...) \
722 _dl_dprintf (STDERR_FILENO, fmt, ##args)
723
724/* Write a message on the specified descriptor standard error and exit
725 the program. The parameters are interpreted as for a `printf' call. */
726#define _dl_fatal_printf(fmt, args...) \
727 do \
728 { \
729 _dl_dprintf (STDERR_FILENO, fmt, ##args); \
730 _exit (127); \
731 } \
732 while (1)
733
734
735/* This function is called by all the internal dynamic linker functions
736 when they encounter an error. ERRCODE is either an `errno' code or
737 zero; OBJECT is the name of the problematical shared object, or null if
738 it is a general problem; ERRSTRING is a string describing the specific
739 problem. */
740extern void _dl_signal_error (int errcode, const char *object,
741 const char *occurred, const char *errstring)
742 internal_function __attribute__ ((__noreturn__));
743libc_hidden_proto (_dl_signal_error)
744
745/* Like _dl_signal_error, but may return when called in the context of
746 _dl_receive_error. This is only used during ld.so bootstrap. In
747 static and profiled builds, this is equivalent to
748 _dl_signal_error. */
749#if IS_IN (rtld)
750extern void _dl_signal_cerror (int errcode, const char *object,
751 const char *occation, const char *errstring)
752 internal_function attribute_hidden;
753#else
754__attribute__ ((always_inline))
755static inline void
756_dl_signal_cerror (int errcode, const char *object,
757 const char *occation, const char *errstring)
758{
759 _dl_signal_error (errcode, object, occation, errstring);
760}
761#endif
762
763/* Call OPERATE, receiving errors from `dl_signal_cerror'. Unlike
764 `_dl_catch_error' the operation is resumed after the OPERATE
765 function returns.
766 ARGS is passed as argument to OPERATE. */
767extern void _dl_receive_error (receiver_fct fct, void (*operate) (void *),
768 void *args)
769 internal_function attribute_hidden;
770
771/* Call OPERATE, catching errors from `dl_signal_error'. If there is no
772 error, *ERRSTRING is set to null. If there is an error, *ERRSTRING is
773 set to a string constructed from the strings passed to _dl_signal_error,
774 and the error code passed is the return value and *OBJNAME is set to
775 the object name which experienced the problems. ERRSTRING if nonzero
776 points to a malloc'ed string which the caller has to free after use.
777 ARGS is passed as argument to OPERATE. MALLOCEDP is set to true only
778 if the returned string is allocated using the libc's malloc. */
779extern int _dl_catch_error (const char **objname, const char **errstring,
780 bool *mallocedp, void (*operate) (void *),
781 void *args)
782 internal_function;
783libc_hidden_proto (_dl_catch_error)
784
785/* Open the shared object NAME and map in its segments.
786 LOADER's DT_RPATH is used in searching for NAME.
787 If the object is already opened, returns its existing map. */
788extern struct link_map *_dl_map_object (struct link_map *loader,
789 const char *name,
790 int type, int trace_mode, int mode,
791 Lmid_t nsid)
792 internal_function attribute_hidden;
793
794/* Call _dl_map_object on the dependencies of MAP, and set up
795 MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously
796 loaded objects that will be inserted into MAP->l_searchlist after MAP
797 but before its dependencies. */
798extern void _dl_map_object_deps (struct link_map *map,
799 struct link_map **preloads,
800 unsigned int npreloads, int trace_mode,
801 int open_mode)
802 internal_function attribute_hidden;
803
804/* Cache the locations of MAP's hash table. */
805extern void _dl_setup_hash (struct link_map *map)
806 internal_function attribute_hidden;
807
808
809/* Collect the directories in the search path for LOADER's dependencies.
810 The data structure is defined in <dlfcn.h>. If COUNTING is true,
811 SI->dls_cnt and SI->dls_size are set; if false, those must be as set
812 by a previous call with COUNTING set, and SI must point to SI->dls_size
813 bytes to be used in filling in the result. */
814extern void _dl_rtld_di_serinfo (struct link_map *loader,
815 Dl_serinfo *si, bool counting)
816 internal_function;
817
818
819/* Search loaded objects' symbol tables for a definition of the symbol
820 referred to by UNDEF. *SYM is the symbol table entry containing the
821 reference; it is replaced with the defining symbol, and the base load
822 address of the defining object is returned. SYMBOL_SCOPE is a
823 null-terminated list of object scopes to search; each object's
824 l_searchlist (i.e. the segment of the dependency tree starting at that
825 object) is searched in turn. REFERENCE_NAME should name the object
826 containing the reference; it is used in error messages.
827 TYPE_CLASS describes the type of symbol we are looking for. */
828enum
829 {
830 /* If necessary add dependency between user and provider object. */
831 DL_LOOKUP_ADD_DEPENDENCY = 1,
832 /* Return most recent version instead of default version for
833 unversioned lookup. */
834 DL_LOOKUP_RETURN_NEWEST = 2,
835 /* Set if dl_lookup* called with GSCOPE lock held. */
836 DL_LOOKUP_GSCOPE_LOCK = 4,
837 };
838
839/* Lookup versioned symbol. */
840extern lookup_t _dl_lookup_symbol_x (const char *undef,
841 struct link_map *undef_map,
842 const ElfW(Sym) **sym,
843 struct r_scope_elem *symbol_scope[],
844 const struct r_found_version *version,
845 int type_class, int flags,
846 struct link_map *skip_map)
847 internal_function attribute_hidden;
848
849
850/* Look up symbol NAME in MAP's scope and return its run-time address. */
851extern ElfW(Addr) _dl_symbol_value (struct link_map *map, const char *name)
852 internal_function;
853
854/* Add the new link_map NEW to the end of the namespace list. */
855extern void _dl_add_to_namespace_list (struct link_map *new, Lmid_t nsid)
856 internal_function attribute_hidden;
857
858/* Allocate a `struct link_map' for a new object being loaded. */
859extern struct link_map *_dl_new_object (char *realname, const char *libname,
860 int type, struct link_map *loader,
861 int mode, Lmid_t nsid)
862 internal_function attribute_hidden;
863
864/* Relocate the given object (if it hasn't already been).
865 SCOPE is passed to _dl_lookup_symbol in symbol lookups.
866 If RTLD_LAZY is set in RELOC-MODE, don't relocate its PLT. */
867extern void _dl_relocate_object (struct link_map *map,
868 struct r_scope_elem *scope[],
869 int reloc_mode, int consider_profiling)
870 attribute_hidden;
871
872/* Protect PT_GNU_RELRO area. */
873extern void _dl_protect_relro (struct link_map *map)
874 internal_function attribute_hidden;
875
876/* Call _dl_signal_error with a message about an unhandled reloc type.
877 TYPE is the result of ELFW(R_TYPE) (r_info), i.e. an R_<CPU>_* value.
878 PLT is nonzero if this was a PLT reloc; it just affects the message. */
879extern void _dl_reloc_bad_type (struct link_map *map,
880 unsigned int type, int plt)
881 internal_function attribute_hidden __attribute__ ((__noreturn__));
882
883/* Resolve conflicts if prelinking. */
884extern void _dl_resolve_conflicts (struct link_map *l,
885 ElfW(Rela) *conflict,
886 ElfW(Rela) *conflictend)
887 attribute_hidden;
888
889/* Check the version dependencies of all objects available through
890 MAP. If VERBOSE print some more diagnostics. */
891extern int _dl_check_all_versions (struct link_map *map, int verbose,
892 int trace_mode)
893 internal_function attribute_hidden;
894
895/* Check the version dependencies for MAP. If VERBOSE print some more
896 diagnostics. */
897extern int _dl_check_map_versions (struct link_map *map, int verbose,
898 int trace_mode)
899 internal_function attribute_hidden;
900
901/* Initialize the object in SCOPE by calling the constructors with
902 ARGC, ARGV, and ENV as the parameters. */
903extern void _dl_init (struct link_map *main_map, int argc, char **argv,
904 char **env) internal_function attribute_hidden;
905
906/* Call the finalizer functions of all shared objects whose
907 initializer functions have completed. */
908extern void _dl_fini (void) internal_function;
909
910/* Sort array MAPS according to dependencies of the contained objects. */
911extern void _dl_sort_fini (struct link_map **maps, size_t nmaps, char *used,
912 Lmid_t ns)
913 internal_function attribute_hidden;
914
915/* The dynamic linker calls this function before and having changing
916 any shared object mappings. The `r_state' member of `struct r_debug'
917 says what change is taking place. This function's address is
918 the value of the `r_brk' member. */
919extern void _dl_debug_state (void);
920rtld_hidden_proto (_dl_debug_state)
921
922/* Initialize `struct r_debug' if it has not already been done. The
923 argument is the run-time load address of the dynamic linker, to be put
924 in the `r_ldbase' member. Returns the address of the structure. */
925extern struct r_debug *_dl_debug_initialize (ElfW(Addr) ldbase, Lmid_t ns)
926 internal_function attribute_hidden;
927
928/* Initialize the basic data structure for the search paths. */
929extern void _dl_init_paths (const char *library_path)
930 internal_function attribute_hidden;
931
932/* Gather the information needed to install the profiling tables and start
933 the timers. */
934extern void _dl_start_profile (void) internal_function attribute_hidden;
935
936/* The actual functions used to keep book on the calls. */
937extern void _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc);
938rtld_hidden_proto (_dl_mcount)
939
940/* This function is simply a wrapper around the _dl_mcount function
941 which does not require a FROMPC parameter since this is the
942 calling function. */
943extern void _dl_mcount_wrapper (void *selfpc);
944
945/* Show the members of the auxiliary array passed up from the kernel. */
946extern void _dl_show_auxv (void)
947 internal_function attribute_hidden;
948
949/* Return all environment variables starting with `LD_', one after the
950 other. */
951extern char *_dl_next_ld_env_entry (char ***position)
952 internal_function attribute_hidden;
953
954/* Return an array with the names of the important hardware capabilities. */
955extern const struct r_strlenpair *_dl_important_hwcaps (const char *platform,
956 size_t paltform_len,
957 size_t *sz,
958 size_t *max_capstrlen)
959 internal_function attribute_hidden;
960
961/* Look up NAME in ld.so.cache and return the file name stored there,
962 or null if none is found. Caller must free returned string. */
963extern char *_dl_load_cache_lookup (const char *name)
964 internal_function attribute_hidden;
965
966/* If the system does not support MAP_COPY we cannot leave the file open
967 all the time since this would create problems when the file is replaced.
968 Therefore we provide this function to close the file and open it again
969 once needed. */
970extern void _dl_unload_cache (void) attribute_hidden;
971
972/* System-dependent function to read a file's whole contents in the
973 most convenient manner available. *SIZEP gets the size of the
974 file. On error MAP_FAILED is returned. */
975extern void *_dl_sysdep_read_whole_file (const char *file, size_t *sizep,
976 int prot)
977 internal_function attribute_hidden;
978
979/* System-specific function to do initial startup for the dynamic linker.
980 After this, file access calls and getenv must work. This is responsible
981 for setting __libc_enable_secure if we need to be secure (e.g. setuid),
982 and for setting _dl_argc and _dl_argv, and then calling _dl_main. */
983extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
984 void (*dl_main) (const ElfW(Phdr) *phdr,
985 ElfW(Word) phnum,
986 ElfW(Addr) *user_entry,
987 ElfW(auxv_t) *auxv))
988 attribute_hidden;
989
990extern void _dl_sysdep_start_cleanup (void)
991 internal_function attribute_hidden;
992
993
994/* Determine next available module ID. */
995extern size_t _dl_next_tls_modid (void) internal_function attribute_hidden;
996
997/* Count the modules with TLS segments. */
998extern size_t _dl_count_modids (void) internal_function attribute_hidden;
999
1000/* Calculate offset of the TLS blocks in the static TLS block. */
1001extern void _dl_determine_tlsoffset (void) internal_function attribute_hidden;
1002
1003#ifndef SHARED
1004/* Set up the TCB for statically linked applications. This is called
1005 early during startup because we always use TLS (for errno and the
1006 stack protector, among other things). */
1007void __libc_setup_tls (void);
1008
1009/* Initialization of libpthread for statically linked applications.
1010 If libpthread is not linked in, this is an empty function. */
1011void __pthread_initialize_minimal (void) weak_function;
1012#endif
1013
1014/* Allocate memory for static TLS block (unless MEM is nonzero) and dtv. */
1015extern void *_dl_allocate_tls (void *mem) internal_function;
1016rtld_hidden_proto (_dl_allocate_tls)
1017
1018/* Get size and alignment requirements of the static TLS block. */
1019extern void _dl_get_tls_static_info (size_t *sizep, size_t *alignp)
1020 internal_function;
1021
1022extern void _dl_allocate_static_tls (struct link_map *map)
1023 internal_function attribute_hidden;
1024
1025/* These are internal entry points to the two halves of _dl_allocate_tls,
1026 only used within rtld.c itself at startup time. */
1027extern void *_dl_allocate_tls_storage (void)
1028 internal_function attribute_hidden;
1029extern void *_dl_allocate_tls_init (void *) internal_function;
1030rtld_hidden_proto (_dl_allocate_tls_init)
1031
1032/* Deallocate memory allocated with _dl_allocate_tls. */
1033extern void _dl_deallocate_tls (void *tcb, bool dealloc_tcb) internal_function;
1034rtld_hidden_proto (_dl_deallocate_tls)
1035
1036extern void _dl_nothread_init_static_tls (struct link_map *) attribute_hidden;
1037
1038/* Find origin of the executable. */
1039extern const char *_dl_get_origin (void) attribute_hidden;
1040
1041/* Count DSTs. */
1042extern size_t _dl_dst_count (const char *name, int is_path) attribute_hidden;
1043
1044/* Substitute DST values. */
1045extern char *_dl_dst_substitute (struct link_map *l, const char *name,
1046 char *result, int is_path) attribute_hidden;
1047
1048/* Check validity of the caller. */
1049extern int _dl_check_caller (const void *caller, enum allowmask mask)
1050 attribute_hidden;
1051
1052/* Open the shared object NAME, relocate it, and run its initializer if it
1053 hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If
1054 the object is already opened, returns its existing map. */
1055extern void *_dl_open (const char *name, int mode, const void *caller,
1056 Lmid_t nsid, int argc, char *argv[], char *env[])
1057 attribute_hidden;
1058
1059/* Free or queue for freeing scope OLD. If other threads might be
1060 in the middle of _dl_fixup, _dl_profile_fixup or dl*sym using the
1061 old scope, OLD can't be freed until no thread is using it. */
1062extern int _dl_scope_free (void *) attribute_hidden;
1063
1064/* Add module to slot information data. */
1065extern void _dl_add_to_slotinfo (struct link_map *l) attribute_hidden;
1066
1067/* Update slot information data for at least the generation of the
1068 module with the given index. */
1069extern struct link_map *_dl_update_slotinfo (unsigned long int req_modid)
1070 attribute_hidden;
1071
1072/* Look up the module's TLS block as for __tls_get_addr,
1073 but never touch anything. Return null if it's not allocated yet. */
1074extern void *_dl_tls_get_addr_soft (struct link_map *l) attribute_hidden;
1075
1076extern int _dl_addr_inside_object (struct link_map *l, const ElfW(Addr) addr)
1077 internal_function attribute_hidden;
1078
1079/* Show show of an object. */
1080extern void _dl_show_scope (struct link_map *new, int from)
1081 attribute_hidden;
1082
1083extern struct link_map *_dl_find_dso_for_object (const ElfW(Addr) addr)
1084 internal_function;
1085rtld_hidden_proto (_dl_find_dso_for_object)
1086
1087/* Initialization which is normally done by the dynamic linker. */
1088extern void _dl_non_dynamic_init (void) internal_function;
1089
1090/* Used by static binaries to check the auxiliary vector. */
1091extern void _dl_aux_init (ElfW(auxv_t) *av) internal_function;
1092
1093
1094__END_DECLS
1095
1096#endif /* ldsodefs.h */
1097