1/* Run-time dynamic linker data structures for loaded ELF shared objects.
2 Copyright (C) 1995-2018 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 attribute_hidden;
252
253/* Compute next higher prime number. */
254extern unsigned long int _dl_higher_prime_number (unsigned long int n)
255 attribute_hidden;
256
257/* A stripped down strtoul-like implementation. */
258uint64_t _dl_strtoul (const char *, char **) attribute_hidden;
259
260/* Function used as argument for `_dl_receive_error' function. The
261 arguments are the error code, error string, and the objname the
262 error occurred in. */
263typedef void (*receiver_fct) (int, const char *, const char *);
264
265/* Internal functions of the run-time dynamic linker.
266 These can be accessed if you link again the dynamic linker
267 as a shared library, as in `-lld' or `/lib/ld.so' explicitly;
268 but are not normally of interest to user programs.
269
270 The `-ldl' library functions in <dlfcn.h> provide a simple
271 user interface to run-time dynamic linking. */
272
273
274#ifndef SHARED
275# define EXTERN extern
276# define GL(name) _##name
277#else
278# define EXTERN
279# if IS_IN (rtld)
280# define GL(name) _rtld_local._##name
281# else
282# define GL(name) _rtld_global._##name
283# endif
284struct rtld_global
285{
286#endif
287 /* Don't change the order of the following elements. 'dl_loaded'
288 must remain the first element. Forever. */
289
290/* Non-shared code has no support for multiple namespaces. */
291#ifdef SHARED
292# define DL_NNS 16
293#else
294# define DL_NNS 1
295#endif
296 EXTERN struct link_namespaces
297 {
298 /* A pointer to the map for the main map. */
299 struct link_map *_ns_loaded;
300 /* Number of object in the _dl_loaded list. */
301 unsigned int _ns_nloaded;
302 /* Direct pointer to the searchlist of the main object. */
303 struct r_scope_elem *_ns_main_searchlist;
304 /* This is zero at program start to signal that the global scope map is
305 allocated by rtld. Later it keeps the size of the map. It might be
306 reset if in _dl_close if the last global object is removed. */
307 size_t _ns_global_scope_alloc;
308 /* Search table for unique objects. */
309 struct unique_sym_table
310 {
311 __rtld_lock_define_recursive (, lock)
312 struct unique_sym
313 {
314 uint32_t hashval;
315 const char *name;
316 const ElfW(Sym) *sym;
317 const struct link_map *map;
318 } *entries;
319 size_t size;
320 size_t n_elements;
321 void (*free) (void *);
322 } _ns_unique_sym_table;
323 /* Keep track of changes to each namespace' list. */
324 struct r_debug _ns_debug;
325 } _dl_ns[DL_NNS];
326 /* One higher than index of last used namespace. */
327 EXTERN size_t _dl_nns;
328
329 /* During the program run we must not modify the global data of
330 loaded shared object simultanously in two threads. Therefore we
331 protect `_dl_open' and `_dl_close' in dl-close.c.
332
333 This must be a recursive lock since the initializer function of
334 the loaded object might as well require a call to this function.
335 At this time it is not anymore a problem to modify the tables. */
336 __rtld_lock_define_recursive (EXTERN, _dl_load_lock)
337 /* This lock is used to keep __dl_iterate_phdr from inspecting the
338 list of loaded objects while an object is added to or removed
339 from that list. */
340 __rtld_lock_define_recursive (EXTERN, _dl_load_write_lock)
341
342 /* Incremented whenever something may have been added to dl_loaded. */
343 EXTERN unsigned long long _dl_load_adds;
344
345 /* The object to be initialized first. */
346 EXTERN struct link_map *_dl_initfirst;
347
348#if HP_SMALL_TIMING_AVAIL
349 /* Start time on CPU clock. */
350 EXTERN hp_timing_t _dl_cpuclock_offset;
351#endif
352
353 /* Map of shared object to be profiled. */
354 EXTERN struct link_map *_dl_profile_map;
355
356 /* Counters for the number of relocations performed. */
357 EXTERN unsigned long int _dl_num_relocations;
358 EXTERN unsigned long int _dl_num_cache_relocations;
359
360 /* List of search directories. */
361 EXTERN struct r_search_path_elem *_dl_all_dirs;
362
363 /* Structure describing the dynamic linker itself. We need to
364 reserve memory for the data the audit libraries need. */
365 EXTERN struct link_map _dl_rtld_map;
366#ifdef SHARED
367 struct auditstate audit_data[DL_NNS];
368#endif
369
370#if defined SHARED && defined _LIBC_REENTRANT \
371 && defined __rtld_lock_default_lock_recursive
372 EXTERN void (*_dl_rtld_lock_recursive) (void *);
373 EXTERN void (*_dl_rtld_unlock_recursive) (void *);
374#endif
375
376 /* Get architecture specific definitions. */
377#define PROCINFO_DECL
378#ifndef PROCINFO_CLASS
379# define PROCINFO_CLASS EXTERN
380#endif
381#include <dl-procruntime.c>
382
383 /* If loading a shared object requires that we make the stack executable
384 when it was not, we do it by calling this function.
385 It returns an errno code or zero on success. */
386 EXTERN int (*_dl_make_stack_executable_hook) (void **);
387
388 /* Prevailing state of the stack, PF_X indicating it's executable. */
389 EXTERN ElfW(Word) _dl_stack_flags;
390
391 /* Flag signalling whether there are gaps in the module ID allocation. */
392 EXTERN bool _dl_tls_dtv_gaps;
393 /* Highest dtv index currently needed. */
394 EXTERN size_t _dl_tls_max_dtv_idx;
395 /* Information about the dtv slots. */
396 EXTERN struct dtv_slotinfo_list
397 {
398 size_t len;
399 struct dtv_slotinfo_list *next;
400 struct dtv_slotinfo
401 {
402 size_t gen;
403 struct link_map *map;
404 } slotinfo[0];
405 } *_dl_tls_dtv_slotinfo_list;
406 /* Number of modules in the static TLS block. */
407 EXTERN size_t _dl_tls_static_nelem;
408 /* Size of the static TLS block. */
409 EXTERN size_t _dl_tls_static_size;
410 /* Size actually allocated in the static TLS block. */
411 EXTERN size_t _dl_tls_static_used;
412 /* Alignment requirement of the static TLS block. */
413 EXTERN size_t _dl_tls_static_align;
414
415/* Number of additional entries in the slotinfo array of each slotinfo
416 list element. A large number makes it almost certain take we never
417 have to iterate beyond the first element in the slotinfo list. */
418#define TLS_SLOTINFO_SURPLUS (62)
419
420/* Number of additional slots in the dtv allocated. */
421#define DTV_SURPLUS (14)
422
423 /* Initial dtv of the main thread, not allocated with normal malloc. */
424 EXTERN void *_dl_initial_dtv;
425 /* Generation counter for the dtv. */
426 EXTERN size_t _dl_tls_generation;
427
428 EXTERN void (*_dl_init_static_tls) (struct link_map *);
429
430 EXTERN void (*_dl_wait_lookup_done) (void);
431
432 /* Scopes to free after next THREAD_GSCOPE_WAIT (). */
433 EXTERN struct dl_scope_free_list
434 {
435 size_t count;
436 void *list[50];
437 } *_dl_scope_free_list;
438#ifdef SHARED
439};
440# define __rtld_global_attribute__
441# if IS_IN (rtld)
442# ifdef HAVE_SDATA_SECTION
443# define __rtld_local_attribute__ \
444 __attribute__ ((visibility ("hidden"), section (".sdata")))
445# undef __rtld_global_attribute__
446# define __rtld_global_attribute__ __attribute__ ((section (".sdata")))
447# else
448# define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
449# endif
450extern struct rtld_global _rtld_local __rtld_local_attribute__;
451# undef __rtld_local_attribute__
452# endif
453extern struct rtld_global _rtld_global __rtld_global_attribute__;
454# undef __rtld_global_attribute__
455#endif
456
457#ifndef SHARED
458# define GLRO(name) _##name
459#else
460# if IS_IN (rtld)
461# define GLRO(name) _rtld_local_ro._##name
462# else
463# define GLRO(name) _rtld_global_ro._##name
464# endif
465struct rtld_global_ro
466{
467#endif
468
469 /* If nonzero the appropriate debug information is printed. */
470 EXTERN int _dl_debug_mask;
471#define DL_DEBUG_LIBS (1 << 0)
472#define DL_DEBUG_IMPCALLS (1 << 1)
473#define DL_DEBUG_BINDINGS (1 << 2)
474#define DL_DEBUG_SYMBOLS (1 << 3)
475#define DL_DEBUG_VERSIONS (1 << 4)
476#define DL_DEBUG_RELOC (1 << 5)
477#define DL_DEBUG_FILES (1 << 6)
478#define DL_DEBUG_STATISTICS (1 << 7)
479#define DL_DEBUG_UNUSED (1 << 8)
480#define DL_DEBUG_SCOPES (1 << 9)
481/* These two are used only internally. */
482#define DL_DEBUG_HELP (1 << 10)
483#define DL_DEBUG_PRELINK (1 << 11)
484
485 /* OS version. */
486 EXTERN unsigned int _dl_osversion;
487 /* Platform name. */
488 EXTERN const char *_dl_platform;
489 EXTERN size_t _dl_platformlen;
490
491 /* Cached value of `getpagesize ()'. */
492 EXTERN size_t _dl_pagesize;
493
494 /* Do we read from ld.so.cache? */
495 EXTERN int _dl_inhibit_cache;
496
497 /* Copy of the content of `_dl_main_searchlist' at startup time. */
498 EXTERN struct r_scope_elem _dl_initial_searchlist;
499
500 /* CLK_TCK as reported by the kernel. */
501 EXTERN int _dl_clktck;
502
503 /* If nonzero print warnings messages. */
504 EXTERN int _dl_verbose;
505
506 /* File descriptor to write debug messages to. */
507 EXTERN int _dl_debug_fd;
508
509 /* Do we do lazy relocations? */
510 EXTERN int _dl_lazy;
511
512 /* Nonzero if runtime lookups should not update the .got/.plt. */
513 EXTERN int _dl_bind_not;
514
515 /* Nonzero if references should be treated as weak during runtime
516 linking. */
517 EXTERN int _dl_dynamic_weak;
518
519 /* Default floating-point control word. */
520 EXTERN fpu_control_t _dl_fpu_control;
521
522 /* Expected cache ID. */
523 EXTERN int _dl_correct_cache_id;
524
525 /* Mask for hardware capabilities that are available. */
526 EXTERN uint64_t _dl_hwcap;
527
528#if !HAVE_TUNABLES
529 /* Mask for important hardware capabilities we honour. */
530 EXTERN uint64_t _dl_hwcap_mask;
531#endif
532
533#ifdef HAVE_AUX_VECTOR
534 /* Pointer to the auxv list supplied to the program at startup. */
535 EXTERN ElfW(auxv_t) *_dl_auxv;
536#endif
537
538 /* Get architecture specific definitions. */
539#include <dl-procinfo.c>
540
541 /* Names of shared object for which the RPATH should be ignored. */
542 EXTERN const char *_dl_inhibit_rpath;
543
544 /* Location of the binary. */
545 EXTERN const char *_dl_origin_path;
546
547 /* -1 if the dynamic linker should honor library load bias,
548 0 if not, -2 use the default (honor biases for normal
549 binaries, don't honor for PIEs). */
550 EXTERN ElfW(Addr) _dl_use_load_bias;
551
552 /* Name of the shared object to be profiled (if any). */
553 EXTERN const char *_dl_profile;
554 /* Filename of the output file. */
555 EXTERN const char *_dl_profile_output;
556 /* Name of the object we want to trace the prelinking. */
557 EXTERN const char *_dl_trace_prelink;
558 /* Map of shared object to be prelink traced. */
559 EXTERN struct link_map *_dl_trace_prelink_map;
560
561 /* All search directories defined at startup. This is assigned a
562 non-NULL pointer by the ld.so startup code (after initialization
563 to NULL), so this can also serve as an indicator whether a copy
564 of ld.so is initialized and active. See the rtld_active function
565 below. */
566 EXTERN struct r_search_path_elem *_dl_init_all_dirs;
567
568#ifdef NEED_DL_SYSINFO
569 /* Syscall handling improvements. This is very specific to x86. */
570 EXTERN uintptr_t _dl_sysinfo;
571#endif
572
573#ifdef NEED_DL_SYSINFO_DSO
574 /* The vsyscall page is a virtual DSO pre-mapped by the kernel.
575 This points to its ELF header. */
576 EXTERN const ElfW(Ehdr) *_dl_sysinfo_dso;
577
578 /* At startup time we set up the normal DSO data structure for it,
579 and this points to it. */
580 EXTERN struct link_map *_dl_sysinfo_map;
581#endif
582
583 /* Mask for more hardware capabilities that are available on some
584 platforms. */
585 EXTERN uint64_t _dl_hwcap2;
586
587#ifdef SHARED
588 /* We add a function table to _rtld_global which is then used to
589 call the function instead of going through the PLT. The result
590 is that we can avoid exporting the functions and we do not jump
591 PLT relocations in libc.so. */
592 void (*_dl_debug_printf) (const char *, ...)
593 __attribute__ ((__format__ (__printf__, 1, 2)));
594 void (*_dl_mcount) (ElfW(Addr) frompc, ElfW(Addr) selfpc);
595 lookup_t (*_dl_lookup_symbol_x) (const char *, struct link_map *,
596 const ElfW(Sym) **, struct r_scope_elem *[],
597 const struct r_found_version *, int, int,
598 struct link_map *);
599 int (*_dl_check_caller) (const void *, enum allowmask);
600 void *(*_dl_open) (const char *file, int mode, const void *caller_dlopen,
601 Lmid_t nsid, int argc, char *argv[], char *env[]);
602 void (*_dl_close) (void *map);
603 void *(*_dl_tls_get_addr_soft) (struct link_map *);
604#ifdef HAVE_DL_DISCOVER_OSVERSION
605 int (*_dl_discover_osversion) (void);
606#endif
607
608 /* List of auditing interfaces. */
609 struct audit_ifaces *_dl_audit;
610 unsigned int _dl_naudit;
611};
612# define __rtld_global_attribute__
613# if IS_IN (rtld)
614# define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
615extern struct rtld_global_ro _rtld_local_ro
616 attribute_relro __rtld_local_attribute__;
617extern struct rtld_global_ro _rtld_global_ro
618 attribute_relro __rtld_global_attribute__;
619# undef __rtld_local_attribute__
620# else
621/* We cheat a bit here. We declare the variable as as const even
622 though it is at startup. */
623extern const struct rtld_global_ro _rtld_global_ro
624 attribute_relro __rtld_global_attribute__;
625# endif
626# undef __rtld_global_attribute__
627#endif
628#undef EXTERN
629
630#ifndef SHARED
631/* dl-support.c defines these and initializes them early on. */
632extern const ElfW(Phdr) *_dl_phdr;
633extern size_t _dl_phnum;
634#endif
635
636/* This is the initial value of GL(dl_make_stack_executable_hook).
637 A threads library can change it. */
638extern int _dl_make_stack_executable (void **stack_endp);
639rtld_hidden_proto (_dl_make_stack_executable)
640
641/* Variable pointing to the end of the stack (or close to it). This value
642 must be constant over the runtime of the application. Some programs
643 might use the variable which results in copy relocations on some
644 platforms. But this does not matter, ld.so can always use the local
645 copy. */
646extern void *__libc_stack_end
647#ifndef LIBC_STACK_END_NOT_RELRO
648 attribute_relro
649#endif
650 ;
651rtld_hidden_proto (__libc_stack_end)
652
653/* Parameters passed to the dynamic linker. */
654extern int _dl_argc attribute_hidden attribute_relro;
655extern char **_dl_argv
656#ifndef DL_ARGV_NOT_RELRO
657 attribute_relro
658#endif
659 ;
660rtld_hidden_proto (_dl_argv)
661#if IS_IN (rtld)
662extern unsigned int _dl_skip_args attribute_hidden
663# ifndef DL_ARGV_NOT_RELRO
664 attribute_relro
665# endif
666 ;
667extern unsigned int _dl_skip_args_internal attribute_hidden
668# ifndef DL_ARGV_NOT_RELRO
669 attribute_relro
670# endif
671 ;
672#endif
673#define rtld_progname _dl_argv[0]
674
675/* Flag set at startup and cleared when the last initializer has run. */
676extern int _dl_starting_up;
677weak_extern (_dl_starting_up)
678rtld_hidden_proto (_dl_starting_up)
679
680/* Random data provided by the kernel. */
681extern void *_dl_random attribute_hidden attribute_relro;
682
683/* OS-dependent function to open the zero-fill device. */
684extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */
685
686
687/* Write message on the debug file descriptor. The parameters are
688 interpreted as for a `printf' call. All the lines start with a
689 tag showing the PID. */
690extern void _dl_debug_printf (const char *fmt, ...)
691 __attribute__ ((__format__ (__printf__, 1, 2))) attribute_hidden;
692
693/* Write message on the debug file descriptor. The parameters are
694 interpreted as for a `printf' call. All the lines buf the first
695 start with a tag showing the PID. */
696extern void _dl_debug_printf_c (const char *fmt, ...)
697 __attribute__ ((__format__ (__printf__, 1, 2))) attribute_hidden;
698
699
700/* Write a message on the specified descriptor FD. The parameters are
701 interpreted as for a `printf' call. */
702#if IS_IN (rtld) || !defined (SHARED)
703extern void _dl_dprintf (int fd, const char *fmt, ...)
704 __attribute__ ((__format__ (__printf__, 2, 3)))
705 attribute_hidden;
706#else
707__attribute__ ((always_inline, __format__ (__printf__, 2, 3)))
708static inline void
709_dl_dprintf (int fd, const char *fmt, ...)
710{
711 /* Use local declaration to avoid includign <stdio.h>. */
712 extern int __dprintf(int fd, const char *format, ...) attribute_hidden;
713 __dprintf (fd, fmt, __builtin_va_arg_pack ());
714}
715#endif
716
717/* Write a message on the specified descriptor standard output. The
718 parameters are interpreted as for a `printf' call. */
719#define _dl_printf(fmt, args...) \
720 _dl_dprintf (STDOUT_FILENO, fmt, ##args)
721
722/* Write a message on the specified descriptor standard error. The
723 parameters are interpreted as for a `printf' call. */
724#define _dl_error_printf(fmt, args...) \
725 _dl_dprintf (STDERR_FILENO, fmt, ##args)
726
727/* Write a message on the specified descriptor standard error and exit
728 the program. The parameters are interpreted as for a `printf' call. */
729#define _dl_fatal_printf(fmt, args...) \
730 do \
731 { \
732 _dl_dprintf (STDERR_FILENO, fmt, ##args); \
733 _exit (127); \
734 } \
735 while (1)
736
737
738/* An exception raised by the _dl_signal_error function family and
739 caught by _dl_catch_error function family. Exceptions themselves
740 are copied as part of the raise operation, but the strings are
741 not. */
742struct dl_exception
743{
744 const char *objname;
745 const char *errstring;
746
747 /* This buffer typically stores both objname and errstring
748 above. */
749 char *message_buffer;
750};
751
752/* Creates a new exception. This calls malloc; if allocation fails,
753 dummy values are inserted. OBJECT is the name of the problematical
754 shared object, or null if its a general problem. ERRSTRING is a
755 string describing the specific problem. */
756void _dl_exception_create (struct dl_exception *, const char *object,
757 const char *errstring)
758 __attribute__ ((nonnull (1, 3)));
759rtld_hidden_proto (_dl_exception_create)
760
761/* Like _dl_exception_create, but create errstring from a format
762 string FMT. Currently, only "%s" and "%%" are supported as format
763 directives. */
764void _dl_exception_create_format (struct dl_exception *, const char *objname,
765 const char *fmt, ...)
766 __attribute__ ((nonnull (1, 3), format (printf, 3, 4)));
767rtld_hidden_proto (_dl_exception_create_format)
768
769/* Deallocate the exception, freeing allocated buffers (if
770 possible). */
771void _dl_exception_free (struct dl_exception *)
772 __attribute__ ((nonnull (1)));
773rtld_hidden_proto (_dl_exception_free)
774
775/* This function is called by all the internal dynamic linker
776 functions when they encounter an error. ERRCODE is either an
777 `errno' code or zero; it specifies the return value of
778 _dl_catch_error. OCCASION is included in the error message if the
779 process is terminated immediately. */
780void _dl_signal_exception (int errcode, struct dl_exception *,
781 const char *occasion)
782 __attribute__ ((__noreturn__));
783libc_hidden_proto (_dl_signal_exception)
784
785/* Like _dl_signal_exception, but creates the exception first. */
786extern void _dl_signal_error (int errcode, const char *object,
787 const char *occasion, const char *errstring)
788 __attribute__ ((__noreturn__));
789libc_hidden_proto (_dl_signal_error)
790
791/* Like _dl_signal_exception, but may return when called in the
792 context of _dl_receive_error. This is only used during ld.so
793 bootstrap. In static and profiled builds, this is equivalent to
794 _dl_signal_exception. */
795#if IS_IN (rtld)
796extern void _dl_signal_cexception (int errcode, struct dl_exception *,
797 const char *occasion) attribute_hidden;
798#else
799__attribute__ ((always_inline))
800static inline void
801_dl_signal_cexception (int errcode, struct dl_exception *exception,
802 const char *occasion)
803{
804 _dl_signal_exception (errcode, exception, occasion);
805}
806#endif
807
808/* See _dl_signal_cexception above. */
809#if IS_IN (rtld)
810extern void _dl_signal_cerror (int errcode, const char *object,
811 const char *occasion, const char *errstring)
812 attribute_hidden;
813#else
814__attribute__ ((always_inline))
815static inline void
816_dl_signal_cerror (int errcode, const char *object,
817 const char *occasion, const char *errstring)
818{
819 _dl_signal_error (errcode, object, occasion, errstring);
820}
821#endif
822
823/* Call OPERATE, receiving errors from `dl_signal_cerror'. Unlike
824 `_dl_catch_error' the operation is resumed after the OPERATE
825 function returns.
826 ARGS is passed as argument to OPERATE. */
827extern void _dl_receive_error (receiver_fct fct, void (*operate) (void *),
828 void *args) attribute_hidden;
829
830/* Call OPERATE, catching errors from `_dl_signal_error' and related
831 functions. If there is no error, *ERRSTRING is set to null. If
832 there is an error, *ERRSTRING is set to a string constructed from
833 the strings passed to _dl_signal_error, and the error code passed
834 is the return value and *OBJNAME is set to the object name which
835 experienced the problems. ERRSTRING if nonzero points to a
836 malloc'ed string which the caller has to free after use. ARGS is
837 passed as argument to OPERATE. MALLOCEDP is set to true only if
838 the returned string is allocated using the libc's malloc. */
839extern int _dl_catch_error (const char **objname, const char **errstring,
840 bool *mallocedp, void (*operate) (void *),
841 void *args);
842libc_hidden_proto (_dl_catch_error)
843
844/* Call OPERATE (ARGS). If no error occurs, set *EXCEPTION to zero.
845 Otherwise, store a copy of the raised exception in *EXCEPTION,
846 which has to be freed by _dl_exception_free. */
847int _dl_catch_exception (struct dl_exception *exception,
848 void (*operate) (void *), void *args);
849libc_hidden_proto (_dl_catch_exception)
850
851/* Open the shared object NAME and map in its segments.
852 LOADER's DT_RPATH is used in searching for NAME.
853 If the object is already opened, returns its existing map. */
854extern struct link_map *_dl_map_object (struct link_map *loader,
855 const char *name,
856 int type, int trace_mode, int mode,
857 Lmid_t nsid) attribute_hidden;
858
859/* Call _dl_map_object on the dependencies of MAP, and set up
860 MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously
861 loaded objects that will be inserted into MAP->l_searchlist after MAP
862 but before its dependencies. */
863extern void _dl_map_object_deps (struct link_map *map,
864 struct link_map **preloads,
865 unsigned int npreloads, int trace_mode,
866 int open_mode)
867 attribute_hidden;
868
869/* Cache the locations of MAP's hash table. */
870extern void _dl_setup_hash (struct link_map *map) attribute_hidden;
871
872
873/* Collect the directories in the search path for LOADER's dependencies.
874 The data structure is defined in <dlfcn.h>. If COUNTING is true,
875 SI->dls_cnt and SI->dls_size are set; if false, those must be as set
876 by a previous call with COUNTING set, and SI must point to SI->dls_size
877 bytes to be used in filling in the result. */
878extern void _dl_rtld_di_serinfo (struct link_map *loader,
879 Dl_serinfo *si, bool counting);
880
881
882/* Search loaded objects' symbol tables for a definition of the symbol
883 referred to by UNDEF. *SYM is the symbol table entry containing the
884 reference; it is replaced with the defining symbol, and the base load
885 address of the defining object is returned. SYMBOL_SCOPE is a
886 null-terminated list of object scopes to search; each object's
887 l_searchlist (i.e. the segment of the dependency tree starting at that
888 object) is searched in turn. REFERENCE_NAME should name the object
889 containing the reference; it is used in error messages.
890 TYPE_CLASS describes the type of symbol we are looking for. */
891enum
892 {
893 /* If necessary add dependency between user and provider object. */
894 DL_LOOKUP_ADD_DEPENDENCY = 1,
895 /* Return most recent version instead of default version for
896 unversioned lookup. */
897 DL_LOOKUP_RETURN_NEWEST = 2,
898 /* Set if dl_lookup* called with GSCOPE lock held. */
899 DL_LOOKUP_GSCOPE_LOCK = 4,
900 };
901
902/* Lookup versioned symbol. */
903extern lookup_t _dl_lookup_symbol_x (const char *undef,
904 struct link_map *undef_map,
905 const ElfW(Sym) **sym,
906 struct r_scope_elem *symbol_scope[],
907 const struct r_found_version *version,
908 int type_class, int flags,
909 struct link_map *skip_map)
910 attribute_hidden;
911
912
913/* Add the new link_map NEW to the end of the namespace list. */
914extern void _dl_add_to_namespace_list (struct link_map *new, Lmid_t nsid)
915 attribute_hidden;
916
917/* Allocate a `struct link_map' for a new object being loaded. */
918extern struct link_map *_dl_new_object (char *realname, const char *libname,
919 int type, struct link_map *loader,
920 int mode, Lmid_t nsid)
921 attribute_hidden;
922
923/* Relocate the given object (if it hasn't already been).
924 SCOPE is passed to _dl_lookup_symbol in symbol lookups.
925 If RTLD_LAZY is set in RELOC-MODE, don't relocate its PLT. */
926extern void _dl_relocate_object (struct link_map *map,
927 struct r_scope_elem *scope[],
928 int reloc_mode, int consider_profiling)
929 attribute_hidden;
930
931/* Protect PT_GNU_RELRO area. */
932extern void _dl_protect_relro (struct link_map *map) attribute_hidden;
933
934/* Call _dl_signal_error with a message about an unhandled reloc type.
935 TYPE is the result of ELFW(R_TYPE) (r_info), i.e. an R_<CPU>_* value.
936 PLT is nonzero if this was a PLT reloc; it just affects the message. */
937extern void _dl_reloc_bad_type (struct link_map *map,
938 unsigned int type, int plt)
939 attribute_hidden __attribute__ ((__noreturn__));
940
941/* Resolve conflicts if prelinking. */
942extern void _dl_resolve_conflicts (struct link_map *l,
943 ElfW(Rela) *conflict,
944 ElfW(Rela) *conflictend)
945 attribute_hidden;
946
947/* Check the version dependencies of all objects available through
948 MAP. If VERBOSE print some more diagnostics. */
949extern int _dl_check_all_versions (struct link_map *map, int verbose,
950 int trace_mode) attribute_hidden;
951
952/* Check the version dependencies for MAP. If VERBOSE print some more
953 diagnostics. */
954extern int _dl_check_map_versions (struct link_map *map, int verbose,
955 int trace_mode) attribute_hidden;
956
957/* Initialize the object in SCOPE by calling the constructors with
958 ARGC, ARGV, and ENV as the parameters. */
959extern void _dl_init (struct link_map *main_map, int argc, char **argv,
960 char **env) attribute_hidden;
961
962/* Call the finalizer functions of all shared objects whose
963 initializer functions have completed. */
964extern void _dl_fini (void) attribute_hidden;
965
966/* Sort array MAPS according to dependencies of the contained objects. */
967extern void _dl_sort_maps (struct link_map **maps, unsigned int nmaps,
968 char *used, bool for_fini) attribute_hidden;
969
970/* The dynamic linker calls this function before and having changing
971 any shared object mappings. The `r_state' member of `struct r_debug'
972 says what change is taking place. This function's address is
973 the value of the `r_brk' member. */
974extern void _dl_debug_state (void);
975rtld_hidden_proto (_dl_debug_state)
976
977/* Initialize `struct r_debug' if it has not already been done. The
978 argument is the run-time load address of the dynamic linker, to be put
979 in the `r_ldbase' member. Returns the address of the structure. */
980extern struct r_debug *_dl_debug_initialize (ElfW(Addr) ldbase, Lmid_t ns)
981 attribute_hidden;
982
983/* Initialize the basic data structure for the search paths. */
984extern void _dl_init_paths (const char *library_path) attribute_hidden;
985
986/* Gather the information needed to install the profiling tables and start
987 the timers. */
988extern void _dl_start_profile (void) attribute_hidden;
989
990/* The actual functions used to keep book on the calls. */
991extern void _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc);
992rtld_hidden_proto (_dl_mcount)
993
994/* This function is simply a wrapper around the _dl_mcount function
995 which does not require a FROMPC parameter since this is the
996 calling function. */
997extern void _dl_mcount_wrapper (void *selfpc);
998
999/* Show the members of the auxiliary array passed up from the kernel. */
1000extern void _dl_show_auxv (void) attribute_hidden;
1001
1002/* Return all environment variables starting with `LD_', one after the
1003 other. */
1004extern char *_dl_next_ld_env_entry (char ***position) attribute_hidden;
1005
1006/* Return an array with the names of the important hardware capabilities. */
1007extern const struct r_strlenpair *_dl_important_hwcaps (const char *platform,
1008 size_t paltform_len,
1009 size_t *sz,
1010 size_t *max_capstrlen)
1011 attribute_hidden;
1012
1013/* Look up NAME in ld.so.cache and return the file name stored there,
1014 or null if none is found. Caller must free returned string. */
1015extern char *_dl_load_cache_lookup (const char *name) attribute_hidden;
1016
1017/* If the system does not support MAP_COPY we cannot leave the file open
1018 all the time since this would create problems when the file is replaced.
1019 Therefore we provide this function to close the file and open it again
1020 once needed. */
1021extern void _dl_unload_cache (void) attribute_hidden;
1022
1023/* System-dependent function to read a file's whole contents in the
1024 most convenient manner available. *SIZEP gets the size of the
1025 file. On error MAP_FAILED is returned. */
1026extern void *_dl_sysdep_read_whole_file (const char *file, size_t *sizep,
1027 int prot) attribute_hidden;
1028
1029/* System-specific function to do initial startup for the dynamic linker.
1030 After this, file access calls and getenv must work. This is responsible
1031 for setting __libc_enable_secure if we need to be secure (e.g. setuid),
1032 and for setting _dl_argc and _dl_argv, and then calling _dl_main. */
1033extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
1034 void (*dl_main) (const ElfW(Phdr) *phdr,
1035 ElfW(Word) phnum,
1036 ElfW(Addr) *user_entry,
1037 ElfW(auxv_t) *auxv))
1038 attribute_hidden;
1039
1040extern void _dl_sysdep_start_cleanup (void) attribute_hidden;
1041
1042
1043/* Determine next available module ID. */
1044extern size_t _dl_next_tls_modid (void) attribute_hidden;
1045
1046/* Count the modules with TLS segments. */
1047extern size_t _dl_count_modids (void) attribute_hidden;
1048
1049/* Calculate offset of the TLS blocks in the static TLS block. */
1050extern void _dl_determine_tlsoffset (void) attribute_hidden;
1051
1052#ifndef SHARED
1053/* Set up the TCB for statically linked applications. This is called
1054 early during startup because we always use TLS (for errno and the
1055 stack protector, among other things). */
1056void __libc_setup_tls (void);
1057
1058# if ENABLE_STATIC_PIE
1059/* Relocate static executable with PIE. */
1060extern void _dl_relocate_static_pie (void) attribute_hidden;
1061
1062/* Get a pointer to _dl_main_map. */
1063extern struct link_map * _dl_get_dl_main_map (void)
1064 __attribute__ ((visibility ("hidden")));
1065# else
1066# define _dl_relocate_static_pie()
1067# endif
1068
1069/* Initialization of libpthread for statically linked applications.
1070 If libpthread is not linked in, this is an empty function. */
1071void __pthread_initialize_minimal (void) weak_function;
1072#endif
1073
1074/* Allocate memory for static TLS block (unless MEM is nonzero) and dtv. */
1075extern void *_dl_allocate_tls (void *mem);
1076rtld_hidden_proto (_dl_allocate_tls)
1077
1078/* Get size and alignment requirements of the static TLS block. */
1079extern void _dl_get_tls_static_info (size_t *sizep, size_t *alignp);
1080
1081extern void _dl_allocate_static_tls (struct link_map *map) attribute_hidden;
1082
1083/* These are internal entry points to the two halves of _dl_allocate_tls,
1084 only used within rtld.c itself at startup time. */
1085extern void *_dl_allocate_tls_storage (void) attribute_hidden;
1086extern void *_dl_allocate_tls_init (void *);
1087rtld_hidden_proto (_dl_allocate_tls_init)
1088
1089/* Deallocate memory allocated with _dl_allocate_tls. */
1090extern void _dl_deallocate_tls (void *tcb, bool dealloc_tcb);
1091rtld_hidden_proto (_dl_deallocate_tls)
1092
1093extern void _dl_nothread_init_static_tls (struct link_map *) attribute_hidden;
1094
1095/* Find origin of the executable. */
1096extern const char *_dl_get_origin (void) attribute_hidden;
1097
1098/* Count DSTs. */
1099extern size_t _dl_dst_count (const char *name) attribute_hidden;
1100
1101/* Substitute DST values. */
1102extern char *_dl_dst_substitute (struct link_map *l, const char *name,
1103 char *result) attribute_hidden;
1104
1105/* Check validity of the caller. */
1106extern int _dl_check_caller (const void *caller, enum allowmask mask)
1107 attribute_hidden;
1108
1109/* Open the shared object NAME, relocate it, and run its initializer if it
1110 hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If
1111 the object is already opened, returns its existing map. */
1112extern void *_dl_open (const char *name, int mode, const void *caller,
1113 Lmid_t nsid, int argc, char *argv[], char *env[])
1114 attribute_hidden;
1115
1116/* Free or queue for freeing scope OLD. If other threads might be
1117 in the middle of _dl_fixup, _dl_profile_fixup or dl*sym using the
1118 old scope, OLD can't be freed until no thread is using it. */
1119extern int _dl_scope_free (void *) attribute_hidden;
1120
1121/* Add module to slot information data. */
1122extern void _dl_add_to_slotinfo (struct link_map *l) attribute_hidden;
1123
1124/* Update slot information data for at least the generation of the
1125 module with the given index. */
1126extern struct link_map *_dl_update_slotinfo (unsigned long int req_modid)
1127 attribute_hidden;
1128
1129/* Look up the module's TLS block as for __tls_get_addr,
1130 but never touch anything. Return null if it's not allocated yet. */
1131extern void *_dl_tls_get_addr_soft (struct link_map *l) attribute_hidden;
1132
1133extern int _dl_addr_inside_object (struct link_map *l, const ElfW(Addr) addr)
1134 attribute_hidden;
1135
1136/* Show show of an object. */
1137extern void _dl_show_scope (struct link_map *new, int from)
1138 attribute_hidden;
1139
1140extern struct link_map *_dl_find_dso_for_object (const ElfW(Addr) addr);
1141rtld_hidden_proto (_dl_find_dso_for_object)
1142
1143/* Initialization which is normally done by the dynamic linker. */
1144extern void _dl_non_dynamic_init (void)
1145 attribute_hidden;
1146
1147/* Used by static binaries to check the auxiliary vector. */
1148extern void _dl_aux_init (ElfW(auxv_t) *av)
1149 attribute_hidden;
1150
1151/* Return true if the ld.so copy in this namespace is actually active
1152 and working. If false, the dl_open/dlfcn hooks have to be used to
1153 call into the outer dynamic linker (which happens after static
1154 dlopen). */
1155#ifdef SHARED
1156static inline bool
1157rtld_active (void)
1158{
1159 /* The default-initialized variable does not have a non-zero
1160 dl_init_all_dirs member, so this allows us to recognize an
1161 initialized and active ld.so copy. */
1162 return GLRO(dl_init_all_dirs) != NULL;
1163}
1164#endif
1165
1166__END_DECLS
1167
1168#endif /* ldsodefs.h */
1169