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/* 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 /* Structure describing the dynamic linker itself. We need to
361 reserve memory for the data the audit libraries need. */
362 EXTERN struct link_map _dl_rtld_map;
363#ifdef SHARED
364 struct auditstate audit_data[DL_NNS];
365#endif
366
367#if defined SHARED && defined _LIBC_REENTRANT \
368 && defined __rtld_lock_default_lock_recursive
369 EXTERN void (*_dl_rtld_lock_recursive) (void *);
370 EXTERN void (*_dl_rtld_unlock_recursive) (void *);
371#endif
372
373 /* If loading a shared object requires that we make the stack executable
374 when it was not, we do it by calling this function.
375 It returns an errno code or zero on success. */
376 EXTERN int (*_dl_make_stack_executable_hook) (void **) internal_function;
377
378 /* Prevailing state of the stack, PF_X indicating it's executable. */
379 EXTERN ElfW(Word) _dl_stack_flags;
380
381 /* Flag signalling whether there are gaps in the module ID allocation. */
382 EXTERN bool _dl_tls_dtv_gaps;
383 /* Highest dtv index currently needed. */
384 EXTERN size_t _dl_tls_max_dtv_idx;
385 /* Information about the dtv slots. */
386 EXTERN struct dtv_slotinfo_list
387 {
388 size_t len;
389 struct dtv_slotinfo_list *next;
390 struct dtv_slotinfo
391 {
392 size_t gen;
393 struct link_map *map;
394 } slotinfo[0];
395 } *_dl_tls_dtv_slotinfo_list;
396 /* Number of modules in the static TLS block. */
397 EXTERN size_t _dl_tls_static_nelem;
398 /* Size of the static TLS block. */
399 EXTERN size_t _dl_tls_static_size;
400 /* Size actually allocated in the static TLS block. */
401 EXTERN size_t _dl_tls_static_used;
402 /* Alignment requirement of the static TLS block. */
403 EXTERN size_t _dl_tls_static_align;
404
405/* Number of additional entries in the slotinfo array of each slotinfo
406 list element. A large number makes it almost certain take we never
407 have to iterate beyond the first element in the slotinfo list. */
408#define TLS_SLOTINFO_SURPLUS (62)
409
410/* Number of additional slots in the dtv allocated. */
411#define DTV_SURPLUS (14)
412
413 /* Initial dtv of the main thread, not allocated with normal malloc. */
414 EXTERN void *_dl_initial_dtv;
415 /* Generation counter for the dtv. */
416 EXTERN size_t _dl_tls_generation;
417
418 EXTERN void (*_dl_init_static_tls) (struct link_map *);
419
420 EXTERN void (*_dl_wait_lookup_done) (void);
421
422 /* Scopes to free after next THREAD_GSCOPE_WAIT (). */
423 EXTERN struct dl_scope_free_list
424 {
425 size_t count;
426 void *list[50];
427 } *_dl_scope_free_list;
428#ifdef SHARED
429};
430# define __rtld_global_attribute__
431# if IS_IN (rtld)
432# ifdef HAVE_SDATA_SECTION
433# define __rtld_local_attribute__ \
434 __attribute__ ((visibility ("hidden"), section (".sdata")))
435# undef __rtld_global_attribute__
436# define __rtld_global_attribute__ __attribute__ ((section (".sdata")))
437# else
438# define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
439# endif
440extern struct rtld_global _rtld_local __rtld_local_attribute__;
441# undef __rtld_local_attribute__
442# endif
443extern struct rtld_global _rtld_global __rtld_global_attribute__;
444# undef __rtld_global_attribute__
445#endif
446
447#ifndef SHARED
448# define GLRO(name) _##name
449#else
450# if IS_IN (rtld)
451# define GLRO(name) _rtld_local_ro._##name
452# else
453# define GLRO(name) _rtld_global_ro._##name
454# endif
455struct rtld_global_ro
456{
457#endif
458
459 /* If nonzero the appropriate debug information is printed. */
460 EXTERN int _dl_debug_mask;
461#define DL_DEBUG_LIBS (1 << 0)
462#define DL_DEBUG_IMPCALLS (1 << 1)
463#define DL_DEBUG_BINDINGS (1 << 2)
464#define DL_DEBUG_SYMBOLS (1 << 3)
465#define DL_DEBUG_VERSIONS (1 << 4)
466#define DL_DEBUG_RELOC (1 << 5)
467#define DL_DEBUG_FILES (1 << 6)
468#define DL_DEBUG_STATISTICS (1 << 7)
469#define DL_DEBUG_UNUSED (1 << 8)
470#define DL_DEBUG_SCOPES (1 << 9)
471/* These two are used only internally. */
472#define DL_DEBUG_HELP (1 << 10)
473#define DL_DEBUG_PRELINK (1 << 11)
474
475 /* OS version. */
476 EXTERN unsigned int _dl_osversion;
477 /* Platform name. */
478 EXTERN const char *_dl_platform;
479 EXTERN size_t _dl_platformlen;
480
481 /* Cached value of `getpagesize ()'. */
482 EXTERN size_t _dl_pagesize;
483
484 /* Do we read from ld.so.cache? */
485 EXTERN int _dl_inhibit_cache;
486
487 /* Copy of the content of `_dl_main_searchlist' at startup time. */
488 EXTERN struct r_scope_elem _dl_initial_searchlist;
489
490 /* CLK_TCK as reported by the kernel. */
491 EXTERN int _dl_clktck;
492
493 /* If nonzero print warnings messages. */
494 EXTERN int _dl_verbose;
495
496 /* File descriptor to write debug messages to. */
497 EXTERN int _dl_debug_fd;
498
499 /* Do we do lazy relocations? */
500 EXTERN int _dl_lazy;
501
502 /* Nonzero if runtime lookups should not update the .got/.plt. */
503 EXTERN int _dl_bind_not;
504
505 /* Nonzero if references should be treated as weak during runtime
506 linking. */
507 EXTERN int _dl_dynamic_weak;
508
509 /* Default floating-point control word. */
510 EXTERN fpu_control_t _dl_fpu_control;
511
512 /* Expected cache ID. */
513 EXTERN int _dl_correct_cache_id;
514
515 /* Mask for hardware capabilities that are available. */
516 EXTERN uint64_t _dl_hwcap;
517
518 /* Mask for important hardware capabilities we honour. */
519 EXTERN uint64_t _dl_hwcap_mask;
520
521#ifdef HAVE_AUX_VECTOR
522 /* Pointer to the auxv list supplied to the program at startup. */
523 EXTERN ElfW(auxv_t) *_dl_auxv;
524#endif
525
526 /* Get architecture specific definitions. */
527#define PROCINFO_DECL
528#ifndef PROCINFO_CLASS
529# define PROCINFO_CLASS EXTERN
530#endif
531#include <dl-procinfo.c>
532
533 /* Names of shared object for which the RPATH should be ignored. */
534 EXTERN const char *_dl_inhibit_rpath;
535
536 /* Location of the binary. */
537 EXTERN const char *_dl_origin_path;
538
539 /* -1 if the dynamic linker should honor library load bias,
540 0 if not, -2 use the default (honor biases for normal
541 binaries, don't honor for PIEs). */
542 EXTERN ElfW(Addr) _dl_use_load_bias;
543
544 /* Name of the shared object to be profiled (if any). */
545 EXTERN const char *_dl_profile;
546 /* Filename of the output file. */
547 EXTERN const char *_dl_profile_output;
548 /* Name of the object we want to trace the prelinking. */
549 EXTERN const char *_dl_trace_prelink;
550 /* Map of shared object to be prelink traced. */
551 EXTERN struct link_map *_dl_trace_prelink_map;
552
553 /* All search directories defined at startup. */
554 EXTERN struct r_search_path_elem *_dl_init_all_dirs;
555
556#ifdef NEED_DL_SYSINFO
557 /* Syscall handling improvements. This is very specific to x86. */
558 EXTERN uintptr_t _dl_sysinfo;
559#endif
560
561#ifdef NEED_DL_SYSINFO_DSO
562 /* The vsyscall page is a virtual DSO pre-mapped by the kernel.
563 This points to its ELF header. */
564 EXTERN const ElfW(Ehdr) *_dl_sysinfo_dso;
565
566 /* At startup time we set up the normal DSO data structure for it,
567 and this points to it. */
568 EXTERN struct link_map *_dl_sysinfo_map;
569#endif
570
571 /* Mask for more hardware capabilities that are available on some
572 platforms. */
573 EXTERN uint64_t _dl_hwcap2;
574
575#ifdef SHARED
576 /* We add a function table to _rtld_global which is then used to
577 call the function instead of going through the PLT. The result
578 is that we can avoid exporting the functions and we do not jump
579 PLT relocations in libc.so. */
580 void (*_dl_debug_printf) (const char *, ...)
581 __attribute__ ((__format__ (__printf__, 1, 2)));
582 void (*_dl_mcount) (ElfW(Addr) frompc, ElfW(Addr) selfpc);
583 lookup_t (internal_function *_dl_lookup_symbol_x) (const char *,
584 struct link_map *,
585 const ElfW(Sym) **,
586 struct r_scope_elem *[],
587 const struct r_found_version *,
588 int, int,
589 struct link_map *);
590 int (*_dl_check_caller) (const void *, enum allowmask);
591 void *(*_dl_open) (const char *file, int mode, const void *caller_dlopen,
592 Lmid_t nsid, int argc, char *argv[], char *env[]);
593 void (*_dl_close) (void *map);
594 void *(*_dl_tls_get_addr_soft) (struct link_map *);
595#ifdef HAVE_DL_DISCOVER_OSVERSION
596 int (*_dl_discover_osversion) (void);
597#endif
598
599 /* List of auditing interfaces. */
600 struct audit_ifaces *_dl_audit;
601 unsigned int _dl_naudit;
602};
603# define __rtld_global_attribute__
604# if IS_IN (rtld)
605# define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
606extern struct rtld_global_ro _rtld_local_ro
607 attribute_relro __rtld_local_attribute__;
608extern struct rtld_global_ro _rtld_global_ro
609 attribute_relro __rtld_global_attribute__;
610# undef __rtld_local_attribute__
611# else
612/* We cheat a bit here. We declare the variable as as const even
613 though it is at startup. */
614extern const struct rtld_global_ro _rtld_global_ro
615 attribute_relro __rtld_global_attribute__;
616# endif
617# undef __rtld_global_attribute__
618#endif
619#undef EXTERN
620
621#ifndef SHARED
622/* dl-support.c defines these and initializes them early on. */
623extern const ElfW(Phdr) *_dl_phdr;
624extern size_t _dl_phnum;
625#endif
626
627/* This is the initial value of GL(dl_make_stack_executable_hook).
628 A threads library can change it. */
629extern int _dl_make_stack_executable (void **stack_endp) internal_function;
630rtld_hidden_proto (_dl_make_stack_executable)
631
632/* Variable pointing to the end of the stack (or close to it). This value
633 must be constant over the runtime of the application. Some programs
634 might use the variable which results in copy relocations on some
635 platforms. But this does not matter, ld.so can always use the local
636 copy. */
637extern void *__libc_stack_end
638#ifndef LIBC_STACK_END_NOT_RELRO
639 attribute_relro
640#endif
641 ;
642rtld_hidden_proto (__libc_stack_end)
643
644/* Parameters passed to the dynamic linker. */
645extern int _dl_argc attribute_hidden attribute_relro;
646extern char **_dl_argv
647#ifndef DL_ARGV_NOT_RELRO
648 attribute_relro
649#endif
650 ;
651rtld_hidden_proto (_dl_argv)
652#if IS_IN (rtld)
653extern unsigned int _dl_skip_args attribute_hidden
654# ifndef DL_ARGV_NOT_RELRO
655 attribute_relro
656# endif
657 ;
658extern unsigned int _dl_skip_args_internal attribute_hidden
659# ifndef DL_ARGV_NOT_RELRO
660 attribute_relro
661# endif
662 ;
663#endif
664#define rtld_progname _dl_argv[0]
665
666/* Flag set at startup and cleared when the last initializer has run. */
667extern int _dl_starting_up;
668weak_extern (_dl_starting_up)
669rtld_hidden_proto (_dl_starting_up)
670
671/* Random data provided by the kernel. */
672extern void *_dl_random attribute_hidden attribute_relro;
673
674/* OS-dependent function to open the zero-fill device. */
675extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */
676
677
678/* Write message on the debug file descriptor. The parameters are
679 interpreted as for a `printf' call. All the lines start with a
680 tag showing the PID. */
681extern void _dl_debug_printf (const char *fmt, ...)
682 __attribute__ ((__format__ (__printf__, 1, 2))) attribute_hidden;
683
684/* Write message on the debug file descriptor. The parameters are
685 interpreted as for a `printf' call. All the lines buf the first
686 start with a tag showing the PID. */
687extern void _dl_debug_printf_c (const char *fmt, ...)
688 __attribute__ ((__format__ (__printf__, 1, 2))) attribute_hidden;
689
690
691/* Write a message on the specified descriptor FD. The parameters are
692 interpreted as for a `printf' call. */
693#if IS_IN (rtld) || !defined (SHARED)
694extern void _dl_dprintf (int fd, const char *fmt, ...)
695 __attribute__ ((__format__ (__printf__, 2, 3)))
696 attribute_hidden;
697#else
698__attribute__ ((always_inline, __format__ (__printf__, 2, 3)))
699static inline void
700_dl_dprintf (int fd, const char *fmt, ...)
701{
702 /* Use local declaration to avoid includign <stdio.h>. */
703 extern int __dprintf(int fd, const char *format, ...) attribute_hidden;
704 __dprintf (fd, fmt, __builtin_va_arg_pack ());
705}
706#endif
707
708/* Write a message on the specified descriptor standard output. The
709 parameters are interpreted as for a `printf' call. */
710#define _dl_printf(fmt, args...) \
711 _dl_dprintf (STDOUT_FILENO, fmt, ##args)
712
713/* Write a message on the specified descriptor standard error. The
714 parameters are interpreted as for a `printf' call. */
715#define _dl_error_printf(fmt, args...) \
716 _dl_dprintf (STDERR_FILENO, fmt, ##args)
717
718/* Write a message on the specified descriptor standard error and exit
719 the program. The parameters are interpreted as for a `printf' call. */
720#define _dl_fatal_printf(fmt, args...) \
721 do \
722 { \
723 _dl_dprintf (STDERR_FILENO, fmt, ##args); \
724 _exit (127); \
725 } \
726 while (1)
727
728
729/* This function is called by all the internal dynamic linker functions
730 when they encounter an error. ERRCODE is either an `errno' code or
731 zero; OBJECT is the name of the problematical shared object, or null if
732 it is a general problem; ERRSTRING is a string describing the specific
733 problem. */
734extern void _dl_signal_error (int errcode, const char *object,
735 const char *occurred, const char *errstring)
736 internal_function __attribute__ ((__noreturn__));
737libc_hidden_proto (_dl_signal_error)
738
739/* Like _dl_signal_error, but may return when called in the context of
740 _dl_receive_error. This is only used during ld.so bootstrap. In
741 static and profiled builds, this is equivalent to
742 _dl_signal_error. */
743#if IS_IN (rtld)
744extern void _dl_signal_cerror (int errcode, const char *object,
745 const char *occation, const char *errstring)
746 internal_function attribute_hidden;
747#else
748__attribute__ ((always_inline))
749static inline void
750_dl_signal_cerror (int errcode, const char *object,
751 const char *occation, const char *errstring)
752{
753 _dl_signal_error (errcode, object, occation, errstring);
754}
755#endif
756
757/* Call OPERATE, receiving errors from `dl_signal_cerror'. Unlike
758 `_dl_catch_error' the operation is resumed after the OPERATE
759 function returns.
760 ARGS is passed as argument to OPERATE. */
761extern void _dl_receive_error (receiver_fct fct, void (*operate) (void *),
762 void *args)
763 internal_function attribute_hidden;
764
765/* Call OPERATE, catching errors from `dl_signal_error'. If there is no
766 error, *ERRSTRING is set to null. If there is an error, *ERRSTRING is
767 set to a string constructed from the strings passed to _dl_signal_error,
768 and the error code passed is the return value and *OBJNAME is set to
769 the object name which experienced the problems. ERRSTRING if nonzero
770 points to a malloc'ed string which the caller has to free after use.
771 ARGS is passed as argument to OPERATE. MALLOCEDP is set to true only
772 if the returned string is allocated using the libc's malloc. */
773extern int _dl_catch_error (const char **objname, const char **errstring,
774 bool *mallocedp, void (*operate) (void *),
775 void *args)
776 internal_function;
777libc_hidden_proto (_dl_catch_error)
778
779/* Open the shared object NAME and map in its segments.
780 LOADER's DT_RPATH is used in searching for NAME.
781 If the object is already opened, returns its existing map. */
782extern struct link_map *_dl_map_object (struct link_map *loader,
783 const char *name,
784 int type, int trace_mode, int mode,
785 Lmid_t nsid)
786 internal_function attribute_hidden;
787
788/* Call _dl_map_object on the dependencies of MAP, and set up
789 MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously
790 loaded objects that will be inserted into MAP->l_searchlist after MAP
791 but before its dependencies. */
792extern void _dl_map_object_deps (struct link_map *map,
793 struct link_map **preloads,
794 unsigned int npreloads, int trace_mode,
795 int open_mode)
796 internal_function attribute_hidden;
797
798/* Cache the locations of MAP's hash table. */
799extern void _dl_setup_hash (struct link_map *map)
800 internal_function attribute_hidden;
801
802
803/* Collect the directories in the search path for LOADER's dependencies.
804 The data structure is defined in <dlfcn.h>. If COUNTING is true,
805 SI->dls_cnt and SI->dls_size are set; if false, those must be as set
806 by a previous call with COUNTING set, and SI must point to SI->dls_size
807 bytes to be used in filling in the result. */
808extern void _dl_rtld_di_serinfo (struct link_map *loader,
809 Dl_serinfo *si, bool counting)
810 internal_function;
811
812
813/* Search loaded objects' symbol tables for a definition of the symbol
814 referred to by UNDEF. *SYM is the symbol table entry containing the
815 reference; it is replaced with the defining symbol, and the base load
816 address of the defining object is returned. SYMBOL_SCOPE is a
817 null-terminated list of object scopes to search; each object's
818 l_searchlist (i.e. the segment of the dependency tree starting at that
819 object) is searched in turn. REFERENCE_NAME should name the object
820 containing the reference; it is used in error messages.
821 TYPE_CLASS describes the type of symbol we are looking for. */
822enum
823 {
824 /* If necessary add dependency between user and provider object. */
825 DL_LOOKUP_ADD_DEPENDENCY = 1,
826 /* Return most recent version instead of default version for
827 unversioned lookup. */
828 DL_LOOKUP_RETURN_NEWEST = 2,
829 /* Set if dl_lookup* called with GSCOPE lock held. */
830 DL_LOOKUP_GSCOPE_LOCK = 4,
831 };
832
833/* Lookup versioned symbol. */
834extern lookup_t _dl_lookup_symbol_x (const char *undef,
835 struct link_map *undef_map,
836 const ElfW(Sym) **sym,
837 struct r_scope_elem *symbol_scope[],
838 const struct r_found_version *version,
839 int type_class, int flags,
840 struct link_map *skip_map)
841 internal_function attribute_hidden;
842
843
844/* Look up symbol NAME in MAP's scope and return its run-time address. */
845extern ElfW(Addr) _dl_symbol_value (struct link_map *map, const char *name)
846 internal_function;
847
848/* Add the new link_map NEW to the end of the namespace list. */
849extern void _dl_add_to_namespace_list (struct link_map *new, Lmid_t nsid)
850 internal_function attribute_hidden;
851
852/* Allocate a `struct link_map' for a new object being loaded. */
853extern struct link_map *_dl_new_object (char *realname, const char *libname,
854 int type, struct link_map *loader,
855 int mode, Lmid_t nsid)
856 internal_function attribute_hidden;
857
858/* Relocate the given object (if it hasn't already been).
859 SCOPE is passed to _dl_lookup_symbol in symbol lookups.
860 If RTLD_LAZY is set in RELOC-MODE, don't relocate its PLT. */
861extern void _dl_relocate_object (struct link_map *map,
862 struct r_scope_elem *scope[],
863 int reloc_mode, int consider_profiling)
864 attribute_hidden;
865
866/* Protect PT_GNU_RELRO area. */
867extern void _dl_protect_relro (struct link_map *map)
868 internal_function attribute_hidden;
869
870/* Call _dl_signal_error with a message about an unhandled reloc type.
871 TYPE is the result of ELFW(R_TYPE) (r_info), i.e. an R_<CPU>_* value.
872 PLT is nonzero if this was a PLT reloc; it just affects the message. */
873extern void _dl_reloc_bad_type (struct link_map *map,
874 unsigned int type, int plt)
875 internal_function attribute_hidden __attribute__ ((__noreturn__));
876
877/* Resolve conflicts if prelinking. */
878extern void _dl_resolve_conflicts (struct link_map *l,
879 ElfW(Rela) *conflict,
880 ElfW(Rela) *conflictend)
881 attribute_hidden;
882
883/* Check the version dependencies of all objects available through
884 MAP. If VERBOSE print some more diagnostics. */
885extern int _dl_check_all_versions (struct link_map *map, int verbose,
886 int trace_mode)
887 internal_function attribute_hidden;
888
889/* Check the version dependencies for MAP. If VERBOSE print some more
890 diagnostics. */
891extern int _dl_check_map_versions (struct link_map *map, int verbose,
892 int trace_mode)
893 internal_function attribute_hidden;
894
895/* Initialize the object in SCOPE by calling the constructors with
896 ARGC, ARGV, and ENV as the parameters. */
897extern void _dl_init (struct link_map *main_map, int argc, char **argv,
898 char **env) internal_function attribute_hidden;
899
900/* Call the finalizer functions of all shared objects whose
901 initializer functions have completed. */
902extern void _dl_fini (void) internal_function;
903
904/* Sort array MAPS according to dependencies of the contained objects. */
905extern void _dl_sort_fini (struct link_map **maps, size_t nmaps, char *used,
906 Lmid_t ns)
907 internal_function attribute_hidden;
908
909/* The dynamic linker calls this function before and having changing
910 any shared object mappings. The `r_state' member of `struct r_debug'
911 says what change is taking place. This function's address is
912 the value of the `r_brk' member. */
913extern void _dl_debug_state (void);
914rtld_hidden_proto (_dl_debug_state)
915
916/* Initialize `struct r_debug' if it has not already been done. The
917 argument is the run-time load address of the dynamic linker, to be put
918 in the `r_ldbase' member. Returns the address of the structure. */
919extern struct r_debug *_dl_debug_initialize (ElfW(Addr) ldbase, Lmid_t ns)
920 internal_function attribute_hidden;
921
922/* Initialize the basic data structure for the search paths. */
923extern void _dl_init_paths (const char *library_path)
924 internal_function attribute_hidden;
925
926/* Gather the information needed to install the profiling tables and start
927 the timers. */
928extern void _dl_start_profile (void) internal_function attribute_hidden;
929
930/* The actual functions used to keep book on the calls. */
931extern void _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc);
932rtld_hidden_proto (_dl_mcount)
933
934/* This function is simply a wrapper around the _dl_mcount function
935 which does not require a FROMPC parameter since this is the
936 calling function. */
937extern void _dl_mcount_wrapper (void *selfpc);
938
939/* Show the members of the auxiliary array passed up from the kernel. */
940extern void _dl_show_auxv (void)
941 internal_function attribute_hidden;
942
943/* Return all environment variables starting with `LD_', one after the
944 other. */
945extern char *_dl_next_ld_env_entry (char ***position)
946 internal_function attribute_hidden;
947
948/* Return an array with the names of the important hardware capabilities. */
949extern const struct r_strlenpair *_dl_important_hwcaps (const char *platform,
950 size_t paltform_len,
951 size_t *sz,
952 size_t *max_capstrlen)
953 internal_function attribute_hidden;
954
955/* Look up NAME in ld.so.cache and return the file name stored there,
956 or null if none is found. Caller must free returned string. */
957extern char *_dl_load_cache_lookup (const char *name)
958 internal_function attribute_hidden;
959
960/* If the system does not support MAP_COPY we cannot leave the file open
961 all the time since this would create problems when the file is replaced.
962 Therefore we provide this function to close the file and open it again
963 once needed. */
964extern void _dl_unload_cache (void) attribute_hidden;
965
966/* System-dependent function to read a file's whole contents in the
967 most convenient manner available. *SIZEP gets the size of the
968 file. On error MAP_FAILED is returned. */
969extern void *_dl_sysdep_read_whole_file (const char *file, size_t *sizep,
970 int prot)
971 internal_function attribute_hidden;
972
973/* System-specific function to do initial startup for the dynamic linker.
974 After this, file access calls and getenv must work. This is responsible
975 for setting __libc_enable_secure if we need to be secure (e.g. setuid),
976 and for setting _dl_argc and _dl_argv, and then calling _dl_main. */
977extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
978 void (*dl_main) (const ElfW(Phdr) *phdr,
979 ElfW(Word) phnum,
980 ElfW(Addr) *user_entry,
981 ElfW(auxv_t) *auxv))
982 attribute_hidden;
983
984extern void _dl_sysdep_start_cleanup (void)
985 internal_function attribute_hidden;
986
987
988/* Determine next available module ID. */
989extern size_t _dl_next_tls_modid (void) internal_function attribute_hidden;
990
991/* Count the modules with TLS segments. */
992extern size_t _dl_count_modids (void) internal_function attribute_hidden;
993
994/* Calculate offset of the TLS blocks in the static TLS block. */
995extern void _dl_determine_tlsoffset (void) internal_function attribute_hidden;
996
997#ifndef SHARED
998/* Set up the TCB for statically linked applications. This is called
999 early during startup because we always use TLS (for errno and the
1000 stack protector, among other things). */
1001void __libc_setup_tls (void);
1002
1003/* Initialization of libpthread for statically linked applications.
1004 If libpthread is not linked in, this is an empty function. */
1005void __pthread_initialize_minimal (void) weak_function;
1006#endif
1007
1008/* Allocate memory for static TLS block (unless MEM is nonzero) and dtv. */
1009extern void *_dl_allocate_tls (void *mem) internal_function;
1010rtld_hidden_proto (_dl_allocate_tls)
1011
1012/* Get size and alignment requirements of the static TLS block. */
1013extern void _dl_get_tls_static_info (size_t *sizep, size_t *alignp)
1014 internal_function;
1015
1016extern void _dl_allocate_static_tls (struct link_map *map)
1017 internal_function attribute_hidden;
1018
1019/* These are internal entry points to the two halves of _dl_allocate_tls,
1020 only used within rtld.c itself at startup time. */
1021extern void *_dl_allocate_tls_storage (void)
1022 internal_function attribute_hidden;
1023extern void *_dl_allocate_tls_init (void *) internal_function;
1024rtld_hidden_proto (_dl_allocate_tls_init)
1025
1026/* Deallocate memory allocated with _dl_allocate_tls. */
1027extern void _dl_deallocate_tls (void *tcb, bool dealloc_tcb) internal_function;
1028rtld_hidden_proto (_dl_deallocate_tls)
1029
1030extern void _dl_nothread_init_static_tls (struct link_map *) attribute_hidden;
1031
1032/* Find origin of the executable. */
1033extern const char *_dl_get_origin (void) attribute_hidden;
1034
1035/* Count DSTs. */
1036extern size_t _dl_dst_count (const char *name, int is_path) attribute_hidden;
1037
1038/* Substitute DST values. */
1039extern char *_dl_dst_substitute (struct link_map *l, const char *name,
1040 char *result, int is_path) attribute_hidden;
1041
1042/* Check validity of the caller. */
1043extern int _dl_check_caller (const void *caller, enum allowmask mask)
1044 attribute_hidden;
1045
1046/* Open the shared object NAME, relocate it, and run its initializer if it
1047 hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If
1048 the object is already opened, returns its existing map. */
1049extern void *_dl_open (const char *name, int mode, const void *caller,
1050 Lmid_t nsid, int argc, char *argv[], char *env[])
1051 attribute_hidden;
1052
1053/* Free or queue for freeing scope OLD. If other threads might be
1054 in the middle of _dl_fixup, _dl_profile_fixup or dl*sym using the
1055 old scope, OLD can't be freed until no thread is using it. */
1056extern int _dl_scope_free (void *) attribute_hidden;
1057
1058/* Add module to slot information data. */
1059extern void _dl_add_to_slotinfo (struct link_map *l) attribute_hidden;
1060
1061/* Update slot information data for at least the generation of the
1062 module with the given index. */
1063extern struct link_map *_dl_update_slotinfo (unsigned long int req_modid)
1064 attribute_hidden;
1065
1066/* Look up the module's TLS block as for __tls_get_addr,
1067 but never touch anything. Return null if it's not allocated yet. */
1068extern void *_dl_tls_get_addr_soft (struct link_map *l) attribute_hidden;
1069
1070extern int _dl_addr_inside_object (struct link_map *l, const ElfW(Addr) addr)
1071 internal_function attribute_hidden;
1072
1073/* Show show of an object. */
1074extern void _dl_show_scope (struct link_map *new, int from)
1075 attribute_hidden;
1076
1077extern struct link_map *_dl_find_dso_for_object (const ElfW(Addr) addr)
1078 internal_function;
1079rtld_hidden_proto (_dl_find_dso_for_object)
1080
1081/* Initialization which is normally done by the dynamic linker. */
1082extern void _dl_non_dynamic_init (void) internal_function;
1083
1084/* Used by static binaries to check the auxiliary vector. */
1085extern void _dl_aux_init (ElfW(auxv_t) *av) internal_function;
1086
1087
1088__END_DECLS
1089
1090#endif /* ldsodefs.h */
1091