1 /* Run-time dynamic linker data structures for loaded ELF shared objects.
2 Copyright (C) 1995-2006, 2007 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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.
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.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
33 #include <fpu_control.h>
36 #include <dl-lookupcfg.h>
37 #include <dl-sysdep.h>
38 #include <bits/libc-lock.h>
39 #include <hp-timing.h>
44 /* We use this macro to refer to ELF types independent of the native wordsize.
45 `ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'. */
46 #define ELFW(type) _ElfW (ELF, __ELF_NATIVE_CLASS, type)
48 /* All references to the value of l_info[DT_PLTGOT],
49 l_info[DT_STRTAB], l_info[DT_SYMTAB], l_info[DT_RELA],
50 l_info[DT_REL], l_info[DT_JMPREL], and l_info[VERSYMIDX (DT_VERSYM)]
51 have to be accessed via the D_PTR macro. The macro is needed since for
52 most architectures the entry is already relocated - but for some not
53 and we need to relocate at access time. */
54 #ifdef DL_RO_DYN_SECTION
55 # define D_PTR(map, i) ((map)->i->d_un.d_ptr + (map)->l_addr)
57 # define D_PTR(map, i) (map)->i->d_un.d_ptr
60 /* Result of the lookup functions and how to retrieve the base address. */
61 typedef struct link_map
*lookup_t
;
62 #define LOOKUP_VALUE(map) map
63 #define LOOKUP_VALUE_ADDRESS(map) ((map) ? (map)->l_addr : 0)
65 /* On some architectures a pointer to a function is not just a pointer
66 to the actual code of the function but rather an architecture
67 specific descriptor. */
68 #ifndef ELF_FUNCTION_PTR_IS_SPECIAL
69 # define DL_SYMBOL_ADDRESS(map, ref) \
70 (void *) (LOOKUP_VALUE_ADDRESS (map) + ref->st_value)
71 # define DL_LOOKUP_ADDRESS(addr) ((ElfW(Addr)) (addr))
72 # define DL_DT_INIT_ADDRESS(map, start) (start)
73 # define DL_DT_FINI_ADDRESS(map, start) (start)
76 /* On some architectures dladdr can't use st_size of all symbols this way. */
77 #define DL_ADDR_SYM_MATCH(L, SYM, MATCHSYM, ADDR) \
78 ((ADDR) >= (L)->l_addr + (SYM)->st_value \
79 && ((((SYM)->st_shndx == SHN_UNDEF || (SYM)->st_size == 0) \
80 && (ADDR) == (L)->l_addr + (SYM)->st_value) \
81 || (ADDR) < (L)->l_addr + (SYM)->st_value + (SYM)->st_size) \
82 && ((MATCHSYM) == NULL || (MATCHSYM)->st_value < (SYM)->st_value))
84 /* Unmap a loaded object, called by _dl_close (). */
85 #ifndef DL_UNMAP_IS_SPECIAL
86 # define DL_UNMAP(map) \
87 __munmap ((void *) (map)->l_map_start, \
88 (map)->l_map_end - (map)->l_map_start)
91 /* By default we do not need special support to initialize DSOs loaded
92 by statically linked binaries. */
93 #ifndef DL_STATIC_INIT
94 # define DL_STATIC_INIT(map)
97 /* Reloc type classes as returned by elf_machine_type_class().
98 ELF_RTYPE_CLASS_PLT means this reloc should not be satisfied by
99 some PLT symbol, ELF_RTYPE_CLASS_COPY means this reloc should not be
100 satisfied by any symbol in the executable. Some architectures do
101 not support copy relocations. In this case we define the macro to
102 zero so that the code for handling them gets automatically optimized
104 #define ELF_RTYPE_CLASS_PLT 1
105 #ifndef DL_NO_COPY_RELOCS
106 # define ELF_RTYPE_CLASS_COPY 2
108 # define ELF_RTYPE_CLASS_COPY 0
111 /* ELF uses the PF_x macros to specify the segment permissions, mmap
112 uses PROT_xxx. In most cases the three macros have the values 1, 2,
113 and 3 but not in a matching order. The following macros allows
114 converting from the PF_x values to PROT_xxx values. */
116 ((PROT_READ << (PF_R * 4)) \
117 | (PROT_WRITE << (PF_W * 4)) \
118 | (PROT_EXEC << (PF_X * 4)) \
119 | ((PROT_READ | PROT_WRITE) << ((PF_R | PF_W) * 4)) \
120 | ((PROT_READ | PROT_EXEC) << ((PF_R | PF_X) * 4)) \
121 | ((PROT_WRITE | PROT_EXEC) << (PF_W | PF_X) * 4) \
122 | ((PROT_READ | PROT_WRITE | PROT_EXEC) << ((PF_R | PF_W | PF_X) * 4)))
125 /* For the version handling we need an array with only names and their
127 struct r_found_version
133 const char *filename
;
136 /* We want to cache information about the searches for shared objects. */
138 enum r_dir_status
{ unknown
, nonexisting
, existing
};
140 struct r_search_path_elem
142 /* This link is only used in the `all_dirs' member of `r_search_path'. */
143 struct r_search_path_elem
*next
;
145 /* Strings saying where the definition came from. */
149 /* Basename for this search path element. The string must end with
150 a slash character. */
154 enum r_dir_status status
[0];
164 /* A data structure for a simple single linked list of strings. */
167 const char *name
; /* Name requested (before search). */
168 struct libname_list
*next
; /* Link to next name for this object. */
169 int dont_free
; /* Flag whether this element should be freed
170 if the object is not entirely unloaded. */
174 /* Bit masks for the objects which valid callers can come from to
175 functions with restricted interface. */
180 allow_libpthread
= 4,
185 /* Type for list of auditing interfaces. */
187 struct La_i86_retval
;
188 struct La_x86_64_regs
;
189 struct La_x86_64_retval
;
190 struct La_ppc32_regs
;
191 struct La_ppc32_retval
;
192 struct La_ppc64_regs
;
193 struct La_ppc64_retval
;
196 struct La_alpha_regs
;
197 struct La_alpha_retval
;
198 struct La_s390_32_regs
;
199 struct La_s390_32_retval
;
200 struct La_s390_64_regs
;
201 struct La_s390_64_retval
;
203 struct La_ia64_retval
;
204 struct La_sparc32_regs
;
205 struct La_sparc32_retval
;
206 struct La_sparc64_regs
;
207 struct La_sparc64_retval
;
211 void (*activity
) (uintptr_t *, unsigned int);
212 char *(*objsearch
) (const char *, uintptr_t *, unsigned int);
213 unsigned int (*objopen
) (struct link_map
*, Lmid_t
, uintptr_t *);
214 void (*preinit
) (uintptr_t *);
217 uintptr_t (*symbind32
) (Elf32_Sym
*, unsigned int, uintptr_t *,
218 uintptr_t *, unsigned int *, const char *);
219 uintptr_t (*symbind64
) (Elf64_Sym
*, unsigned int, uintptr_t *,
220 uintptr_t *, unsigned int *, const char *);
224 Elf32_Addr (*i86_gnu_pltenter
) (Elf32_Sym
*, unsigned int, uintptr_t *,
225 uintptr_t *, struct La_i86_regs
*,
226 unsigned int *, const char *name
,
227 long int *framesizep
);
228 Elf64_Addr (*x86_64_gnu_pltenter
) (Elf64_Sym
*, unsigned int, uintptr_t *,
229 uintptr_t *, struct La_x86_64_regs
*,
230 unsigned int *, const char *name
,
231 long int *framesizep
);
232 Elf32_Addr (*ppc32_gnu_pltenter
) (Elf32_Sym
*, unsigned int, uintptr_t *,
233 uintptr_t *, struct La_ppc32_regs
*,
234 unsigned int *, const char *name
,
235 long int *framesizep
);
236 Elf64_Addr (*ppc64_gnu_pltenter
) (Elf64_Sym
*, unsigned int, uintptr_t *,
237 uintptr_t *, struct La_ppc64_regs
*,
238 unsigned int *, const char *name
,
239 long int *framesizep
);
240 uintptr_t (*sh_gnu_pltenter
) (Elf32_Sym
*, unsigned int, uintptr_t *,
241 uintptr_t *, const struct La_sh_regs
*,
242 unsigned int *, const char *name
,
243 long int *framesizep
);
244 Elf64_Addr (*alpha_gnu_pltenter
) (Elf64_Sym
*, unsigned int, uintptr_t *,
245 uintptr_t *, struct La_alpha_regs
*,
246 unsigned int *, const char *name
,
247 long int *framesizep
);
248 Elf32_Addr (*s390_32_gnu_pltenter
) (Elf32_Sym
*, unsigned int, uintptr_t *,
249 uintptr_t *, struct La_s390_32_regs
*,
250 unsigned int *, const char *name
,
251 long int *framesizep
);
252 Elf64_Addr (*s390_64_gnu_pltenter
) (Elf64_Sym
*, unsigned int, uintptr_t *,
253 uintptr_t *, struct La_s390_64_regs
*,
254 unsigned int *, const char *name
,
255 long int *framesizep
);
256 Elf64_Addr (*ia64_gnu_pltenter
) (Elf64_Sym
*, unsigned int, uintptr_t *,
257 uintptr_t *, struct La_ia64_regs
*,
258 unsigned int *, const char *name
,
259 long int *framesizep
);
260 Elf32_Addr (*sparc32_gnu_pltenter
) (Elf32_Sym
*, unsigned int,
261 uintptr_t *, uintptr_t *,
262 const struct La_sparc32_regs
*,
263 unsigned int *, const char *name
,
264 long int *framesizep
);
265 Elf64_Addr (*sparc64_gnu_pltenter
) (Elf64_Sym
*, unsigned int,
266 uintptr_t *, uintptr_t *,
267 const struct La_sparc64_regs
*,
268 unsigned int *, const char *name
,
269 long int *framesizep
);
270 #ifdef ARCH_PLTENTER_MEMBERS
271 ARCH_PLTENTER_MEMBERS
;
276 unsigned int (*i86_gnu_pltexit
) (Elf32_Sym
*, unsigned int, uintptr_t *,
277 uintptr_t *, const struct La_i86_regs
*,
278 struct La_i86_retval
*, const char *);
279 unsigned int (*x86_64_gnu_pltexit
) (Elf64_Sym
*, unsigned int, uintptr_t *,
281 const struct La_x86_64_regs
*,
282 struct La_x86_64_retval
*,
284 unsigned int (*ppc32_gnu_pltexit
) (Elf32_Sym
*, unsigned int, uintptr_t *,
286 const struct La_ppc32_regs
*,
287 struct La_ppc32_retval
*, const char *);
288 unsigned int (*ppc64_gnu_pltexit
) (Elf64_Sym
*, unsigned int, uintptr_t *,
290 const struct La_ppc64_regs
*,
291 struct La_ppc64_retval
*, const char *);
292 unsigned int (*sh_gnu_pltexit
) (Elf32_Sym
*, unsigned int, uintptr_t *,
293 uintptr_t *, const struct La_sh_regs
*,
294 struct La_sh_retval
*, const char *);
295 unsigned int (*alpha_gnu_pltexit
) (Elf64_Sym
*, unsigned int, uintptr_t *,
297 const struct La_alpha_regs
*,
298 struct La_alpha_retval
*, const char *);
299 unsigned int (*s390_32_gnu_pltexit
) (Elf32_Sym
*, unsigned int,
300 uintptr_t *, uintptr_t *,
301 const struct La_s390_32_regs
*,
302 struct La_s390_32_retval
*,
304 unsigned int (*s390_64_gnu_pltexit
) (Elf64_Sym
*, unsigned int,
305 uintptr_t *, uintptr_t *,
306 const struct La_s390_64_regs
*,
307 struct La_s390_64_retval
*,
309 unsigned int (*ia64_gnu_pltexit
) (Elf64_Sym
*, unsigned int, uintptr_t *,
311 const struct La_ia64_regs
*,
312 struct La_ia64_retval
*, const char *);
313 unsigned int (*sparc32_gnu_pltexit
) (Elf32_Sym
*, unsigned int,
314 uintptr_t *, uintptr_t *,
315 const struct La_sparc32_regs
*,
316 struct La_sparc32_retval
*,
318 unsigned int (*sparc64_gnu_pltexit
) (Elf64_Sym
*, unsigned int,
319 uintptr_t *, uintptr_t *,
320 const struct La_sparc32_regs
*,
321 struct La_sparc32_retval
*,
323 #ifdef ARCH_PLTEXIT_MEMBERS
324 ARCH_PLTEXIT_MEMBERS
;
327 unsigned int (*objclose
) (uintptr_t *);
329 struct audit_ifaces
*next
;
333 /* Test whether given NAME matches any of the names of the given object. */
334 extern int _dl_name_match_p (const char *__name
, const struct link_map
*__map
)
337 /* Function used as argument for `_dl_receive_error' function. The
338 arguments are the error code, error string, and the objname the
339 error occurred in. */
340 typedef void (*receiver_fct
) (int, const char *, const char *);
342 /* Internal functions of the run-time dynamic linker.
343 These can be accessed if you link again the dynamic linker
344 as a shared library, as in `-lld' or `/lib/ld.so' explicitly;
345 but are not normally of interest to user programs.
347 The `-ldl' library functions in <dlfcn.h> provide a simple
348 user interface to run-time dynamic linking. */
352 # define EXTERN extern
353 # define GL(name) _##name
357 # define GL(name) _rtld_local._##name
359 # define GL(name) _rtld_global._##name
364 /* Don't change the order of the following elements. 'dl_loaded'
365 must remain the first element. Forever. */
367 /* Non-shared code has no support for multiple namespaces. */
373 EXTERN
struct link_namespaces
375 /* A pointer to the map for the main map. */
376 struct link_map
*_ns_loaded
;
377 /* Number of object in the _dl_loaded list. */
378 unsigned int _ns_nloaded
;
379 /* Direct pointer to the searchlist of the main object. */
380 struct r_scope_elem
*_ns_main_searchlist
;
381 /* This is zero at program start to signal that the global scope map is
382 allocated by rtld. Later it keeps the size of the map. It might be
383 reset if in _dl_close if the last global object is removed. */
384 size_t _ns_global_scope_alloc
;
385 /* Keep track of changes to each namespace' list. */
386 struct r_debug _ns_debug
;
389 /* During the program run we must not modify the global data of
390 loaded shared object simultanously in two threads. Therefore we
391 protect `_dl_open' and `_dl_close' in dl-close.c.
393 This must be a recursive lock since the initializer function of
394 the loaded object might as well require a call to this function.
395 At this time it is not anymore a problem to modify the tables. */
396 __rtld_lock_define_recursive (EXTERN
, _dl_load_lock
)
398 /* Incremented whenever something may have been added to dl_loaded. */
399 EXTERN
unsigned long long _dl_load_adds
;
402 /* File descriptor referring to the zero-fill device. */
403 EXTERN
int _dl_zerofd
;
406 /* The object to be initialized first. */
407 EXTERN
struct link_map
*_dl_initfirst
;
409 #if HP_TIMING_AVAIL || HP_SMALL_TIMING_AVAIL
410 /* Start time on CPU clock. */
411 EXTERN hp_timing_t _dl_cpuclock_offset
;
414 /* Map of shared object to be profiled. */
415 EXTERN
struct link_map
*_dl_profile_map
;
417 /* Counters for the number of relocations performed. */
418 EXTERN
unsigned long int _dl_num_relocations
;
419 EXTERN
unsigned long int _dl_num_cache_relocations
;
421 /* List of search directories. */
422 EXTERN
struct r_search_path_elem
*_dl_all_dirs
;
424 #ifdef _LIBC_REENTRANT
425 EXTERN
void **(*_dl_error_catch_tsd
) (void) __attribute__ ((const));
428 /* Structure describing the dynamic linker itself. We need to
429 reserve memory for the data the audit libraries need. */
430 EXTERN
struct link_map _dl_rtld_map
;
432 struct auditstate audit_data
[DL_NNS
];
435 #if defined SHARED && defined _LIBC_REENTRANT \
436 && defined __rtld_lock_default_lock_recursive
437 EXTERN
void (*_dl_rtld_lock_recursive
) (void *);
438 EXTERN
void (*_dl_rtld_unlock_recursive
) (void *);
441 /* If loading a shared object requires that we make the stack executable
442 when it was not, we do it by calling this function.
443 It returns an errno code or zero on success. */
444 EXTERN
int (*_dl_make_stack_executable_hook
) (void **) internal_function
;
446 /* Prevailing state of the stack, PF_X indicating it's executable. */
447 EXTERN
ElfW(Word
) _dl_stack_flags
;
449 /* Keep the conditional TLS members at the end so the layout of the
450 structure used by !USE_TLS code matches the prefix of the layout in
451 the USE_TLS rtld. Note that `struct link_map' is conditionally
452 defined as well, so _dl_rtld_map needs to be last before this. */
454 /* Flag signalling whether there are gaps in the module ID allocation. */
455 EXTERN
bool _dl_tls_dtv_gaps
;
456 /* Highest dtv index currently needed. */
457 EXTERN
size_t _dl_tls_max_dtv_idx
;
458 /* Information about the dtv slots. */
459 EXTERN
struct dtv_slotinfo_list
462 struct dtv_slotinfo_list
*next
;
466 struct link_map
*map
;
468 } *_dl_tls_dtv_slotinfo_list
;
469 /* Number of modules in the static TLS block. */
470 EXTERN
size_t _dl_tls_static_nelem
;
471 /* Size of the static TLS block. */
472 EXTERN
size_t _dl_tls_static_size
;
473 /* Size actually allocated in the static TLS block. */
474 EXTERN
size_t _dl_tls_static_used
;
475 /* Alignment requirement of the static TLS block. */
476 EXTERN
size_t _dl_tls_static_align
;
478 /* Number of additional entries in the slotinfo array of each slotinfo
479 list element. A large number makes it almost certain take we never
480 have to iterate beyond the first element in the slotinfo list. */
481 # define TLS_SLOTINFO_SURPLUS (62)
483 /* Number of additional slots in the dtv allocated. */
484 # define DTV_SURPLUS (14)
486 /* Initial dtv of the main thread, not allocated with normal malloc. */
487 EXTERN
void *_dl_initial_dtv
;
488 /* Generation counter for the dtv. */
489 EXTERN
size_t _dl_tls_generation
;
491 EXTERN
void (*_dl_init_static_tls
) (struct link_map
*);
494 EXTERN
void (*_dl_wait_lookup_done
) (void);
496 /* Scopes to free after next THREAD_GSCOPE_WAIT (). */
497 EXTERN
struct dl_scope_free_list
500 struct r_scope_elem
**list
[50];
501 } *_dl_scope_free_list
;
504 # define __rtld_global_attribute__
506 # ifdef HAVE_VISIBILITY_ATTRIBUTE
507 # ifdef HAVE_SDATA_SECTION
508 # define __rtld_local_attribute__ \
509 __attribute__ ((visibility ("hidden"), section (".sdata")))
510 # undef __rtld_global_attribute__
511 # define __rtld_global_attribute__ __attribute__ ((section (".sdata")))
513 # define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
516 # define __rtld_local_attribute__
518 extern struct rtld_global _rtld_local __rtld_local_attribute__
;
519 # undef __rtld_local_attribute__
521 extern struct rtld_global _rtld_global __rtld_global_attribute__
;
522 # undef __rtld_global_attribute__
526 # define GLRO(name) _##name
529 # define GLRO(name) _rtld_local_ro._##name
531 # define GLRO(name) _rtld_global_ro._##name
533 struct rtld_global_ro
537 /* If nonzero the appropriate debug information is printed. */
538 EXTERN
int _dl_debug_mask
;
539 #define DL_DEBUG_LIBS (1 << 0)
540 #define DL_DEBUG_IMPCALLS (1 << 1)
541 #define DL_DEBUG_BINDINGS (1 << 2)
542 #define DL_DEBUG_SYMBOLS (1 << 3)
543 #define DL_DEBUG_VERSIONS (1 << 4)
544 #define DL_DEBUG_RELOC (1 << 5)
545 #define DL_DEBUG_FILES (1 << 6)
546 #define DL_DEBUG_STATISTICS (1 << 7)
547 #define DL_DEBUG_UNUSED (1 << 8)
548 /* These two are used only internally. */
549 #define DL_DEBUG_HELP (1 << 9)
550 #define DL_DEBUG_PRELINK (1 << 10)
553 EXTERN
unsigned int _dl_osversion
;
555 EXTERN
const char *_dl_platform
;
556 EXTERN
size_t _dl_platformlen
;
558 /* Cached value of `getpagesize ()'. */
559 EXTERN
size_t _dl_pagesize
;
561 /* Copy of the content of `_dl_main_searchlist' at startup time. */
562 EXTERN
struct r_scope_elem _dl_initial_searchlist
;
564 /* CLK_TCK as reported by the kernel. */
565 EXTERN
int _dl_clktck
;
567 /* If nonzero print warnings messages. */
568 EXTERN
int _dl_verbose
;
570 /* File descriptor to write debug messages to. */
571 EXTERN
int _dl_debug_fd
;
573 /* Do we do lazy relocations? */
576 /* Nonzero if runtime lookups should not update the .got/.plt. */
577 EXTERN
int _dl_bind_not
;
579 /* Nonzero if references should be treated as weak during runtime
581 EXTERN
int _dl_dynamic_weak
;
583 /* Default floating-point control word. */
584 EXTERN fpu_control_t _dl_fpu_control
;
586 /* Expected cache ID. */
587 EXTERN
int _dl_correct_cache_id
;
589 /* Mask for hardware capabilities that are available. */
590 EXTERN
uint64_t _dl_hwcap
;
592 /* Mask for important hardware capabilities we honour. */
593 EXTERN
uint64_t _dl_hwcap_mask
;
595 /* Get architecture specific definitions. */
596 #define PROCINFO_DECL
597 #ifndef PROCINFO_CLASS
598 # define PROCINFO_CLASS EXTERN
600 #include <dl-procinfo.c>
602 /* Names of shared object for which the RPATH should be ignored. */
603 EXTERN
const char *_dl_inhibit_rpath
;
605 /* Location of the binary. */
606 EXTERN
const char *_dl_origin_path
;
608 /* -1 if the dynamic linker should honor library load bias,
609 0 if not, -2 use the default (honor biases for normal
610 binaries, don't honor for PIEs). */
611 EXTERN
ElfW(Addr
) _dl_use_load_bias
;
613 /* Name of the shared object to be profiled (if any). */
614 EXTERN
const char *_dl_profile
;
615 /* Filename of the output file. */
616 EXTERN
const char *_dl_profile_output
;
617 /* Name of the object we want to trace the prelinking. */
618 EXTERN
const char *_dl_trace_prelink
;
619 /* Map of shared object to be prelink traced. */
620 EXTERN
struct link_map
*_dl_trace_prelink_map
;
622 /* All search directories defined at startup. */
623 EXTERN
struct r_search_path_elem
*_dl_init_all_dirs
;
625 #if HP_TIMING_AVAIL || HP_SMALL_TIMING_AVAIL
626 /* Overhead of a high-precision timing measurement. */
627 EXTERN hp_timing_t _dl_hp_timing_overhead
;
630 #ifdef NEED_DL_SYSINFO
631 /* Syscall handling improvements. This is very specific to x86. */
632 EXTERN
uintptr_t _dl_sysinfo
;
635 #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
636 /* The vsyscall page is a virtual DSO pre-mapped by the kernel.
637 This points to its ELF header. */
638 EXTERN
const ElfW(Ehdr
) *_dl_sysinfo_dso
;
640 /* At startup time we set up the normal DSO data structure for it,
641 and this points to it. */
642 EXTERN
struct link_map
*_dl_sysinfo_map
;
646 /* We add a function table to _rtld_global which is then used to
647 call the function instead of going through the PLT. The result
648 is that we can avoid exporting the functions and we do not jump
649 PLT relocations in libc.so. */
650 void (*_dl_debug_printf
) (const char *, ...)
651 __attribute__ ((__format__ (__printf__
, 1, 2)));
652 int (internal_function
*_dl_catch_error
) (const char **, const char **,
653 bool *, void (*) (void *), void *);
654 void (internal_function
*_dl_signal_error
) (int, const char *, const char *,
656 void (*_dl_mcount
) (ElfW(Addr
) frompc
, ElfW(Addr
) selfpc
);
657 lookup_t (internal_function
*_dl_lookup_symbol_x
) (const char *,
660 struct r_scope_elem
*[],
661 const struct r_found_version
*,
664 int (*_dl_check_caller
) (const void *, enum allowmask
);
665 void *(*_dl_open
) (const char *file
, int mode
, const void *caller_dlopen
,
666 Lmid_t nsid
, int argc
, char *argv
[], char *env
[]);
667 void (*_dl_close
) (void *map
);
669 /* List of auditing interfaces. */
670 struct audit_ifaces
*_dl_audit
;
671 unsigned int _dl_naudit
;
673 /* 0 if internal pointer values should not be guarded, 1 if they should. */
674 EXTERN
int _dl_pointer_guard
;
676 # define __rtld_global_attribute__
678 # ifdef HAVE_VISIBILITY_ATTRIBUTE
679 # define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
681 # define __rtld_local_attribute__
683 extern struct rtld_global_ro _rtld_local_ro
684 attribute_relro __rtld_local_attribute__
;
685 extern struct rtld_global_ro _rtld_global_ro
686 attribute_relro __rtld_global_attribute__
;
687 # undef __rtld_local_attribute__
689 /* We cheat a bit here. We declare the variable as as const even
690 though it is at startup. */
691 extern const struct rtld_global_ro _rtld_global_ro
692 attribute_relro __rtld_global_attribute__
;
694 # undef __rtld_global_attribute__
699 /* This is the initial value of GL(dl_error_catch_tsd).
700 A non-TLS libpthread will change it. */
701 extern void **_dl_initial_error_catch_tsd (void) __attribute__ ((const))
705 /* This is the initial value of GL(dl_make_stack_executable_hook).
706 A threads library can change it. */
707 extern int _dl_make_stack_executable (void **stack_endp
) internal_function
;
708 rtld_hidden_proto (_dl_make_stack_executable
)
710 /* Variable pointing to the end of the stack (or close to it). This value
711 must be constant over the runtime of the application. Some programs
712 might use the variable which results in copy relocations on some
713 platforms. But this does not matter, ld.so can always use the local
715 extern void *__libc_stack_end attribute_relro
;
716 rtld_hidden_proto (__libc_stack_end
)
718 /* Parameters passed to the dynamic linker. */
719 extern int _dl_argc attribute_hidden attribute_relro
;
720 extern char **_dl_argv
721 #ifndef DL_ARGV_NOT_RELRO
726 extern char **_dl_argv_internal attribute_hidden
727 # ifndef DL_ARGV_NOT_RELRO
731 # define rtld_progname (INTUSE(_dl_argv)[0])
733 # define rtld_progname _dl_argv[0]
736 /* Flag set at startup and cleared when the last initializer has run. */
737 extern int _dl_starting_up
;
738 weak_extern (_dl_starting_up
)
740 extern int _dl_starting_up_internal attribute_hidden
;
743 /* OS-dependent function to open the zero-fill device. */
744 extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */
747 /* Write message on the debug file descriptor. The parameters are
748 interpreted as for a `printf' call. All the lines start with a
749 tag showing the PID. */
750 extern void _dl_debug_printf (const char *fmt
, ...)
751 __attribute__ ((__format__ (__printf__
, 1, 2))) attribute_hidden
;
753 /* Write message on the debug file descriptor. The parameters are
754 interpreted as for a `printf' call. All the lines buf the first
755 start with a tag showing the PID. */
756 extern void _dl_debug_printf_c (const char *fmt
, ...)
757 __attribute__ ((__format__ (__printf__
, 1, 2)));
760 /* Write a message on the specified descriptor FD. The parameters are
761 interpreted as for a `printf' call. */
762 extern void _dl_dprintf (int fd
, const char *fmt
, ...)
763 __attribute__ ((__format__ (__printf__
, 2, 3)))
766 /* Write a message on the specified descriptor standard output. The
767 parameters are interpreted as for a `printf' call. */
768 #define _dl_printf(fmt, args...) \
769 _dl_dprintf (STDOUT_FILENO, fmt, ##args)
771 /* Write a message on the specified descriptor standard error. The
772 parameters are interpreted as for a `printf' call. */
773 #define _dl_error_printf(fmt, args...) \
774 _dl_dprintf (STDERR_FILENO, fmt, ##args)
776 /* Write a message on the specified descriptor standard error and exit
777 the program. The parameters are interpreted as for a `printf' call. */
778 #define _dl_fatal_printf(fmt, args...) \
781 _dl_dprintf (STDERR_FILENO, fmt, ##args); \
787 /* This function is called by all the internal dynamic linker functions
788 when they encounter an error. ERRCODE is either an `errno' code or
789 zero; OBJECT is the name of the problematical shared object, or null if
790 it is a general problem; ERRSTRING is a string describing the specific
792 extern void _dl_signal_error (int errcode
, const char *object
,
793 const char *occurred
, const char *errstring
)
794 internal_function
__attribute__ ((__noreturn__
)) attribute_hidden
;
796 /* Like _dl_signal_error, but may return when called in the context of
797 _dl_receive_error. */
798 extern void _dl_signal_cerror (int errcode
, const char *object
,
799 const char *occation
, const char *errstring
)
802 /* Call OPERATE, receiving errors from `dl_signal_cerror'. Unlike
803 `_dl_catch_error' the operation is resumed after the OPERATE
805 ARGS is passed as argument to OPERATE. */
806 extern void _dl_receive_error (receiver_fct fct
, void (*operate
) (void *),
811 /* Open the shared object NAME and map in its segments.
812 LOADER's DT_RPATH is used in searching for NAME.
813 If the object is already opened, returns its existing map.
814 For preloaded shared objects PRELOADED is set to a non-zero
815 value to allow additional security checks. */
816 extern struct link_map
*_dl_map_object (struct link_map
*loader
,
817 const char *name
, int preloaded
,
818 int type
, int trace_mode
, int mode
,
820 internal_function attribute_hidden
;
822 /* Call _dl_map_object on the dependencies of MAP, and set up
823 MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously
824 loaded objects that will be inserted into MAP->l_searchlist after MAP
825 but before its dependencies. */
826 extern void _dl_map_object_deps (struct link_map
*map
,
827 struct link_map
**preloads
,
828 unsigned int npreloads
, int trace_mode
,
830 internal_function attribute_hidden
;
832 /* Cache the locations of MAP's hash table. */
833 extern void _dl_setup_hash (struct link_map
*map
)
834 internal_function attribute_hidden
;
837 /* Collect the directories in the search path for LOADER's dependencies.
838 The data structure is defined in <dlfcn.h>. If COUNTING is true,
839 SI->dls_cnt and SI->dls_size are set; if false, those must be as set
840 by a previous call with COUNTING set, and SI must point to SI->dls_size
841 bytes to be used in filling in the result. */
842 extern void _dl_rtld_di_serinfo (struct link_map
*loader
,
843 Dl_serinfo
*si
, bool counting
)
847 /* Search loaded objects' symbol tables for a definition of the symbol
848 referred to by UNDEF. *SYM is the symbol table entry containing the
849 reference; it is replaced with the defining symbol, and the base load
850 address of the defining object is returned. SYMBOL_SCOPE is a
851 null-terminated list of object scopes to search; each object's
852 l_searchlist (i.e. the segment of the dependency tree starting at that
853 object) is searched in turn. REFERENCE_NAME should name the object
854 containing the reference; it is used in error messages.
855 TYPE_CLASS describes the type of symbol we are looking for. */
858 /* If necessary add dependency between user and provider object. */
859 DL_LOOKUP_ADD_DEPENDENCY
= 1,
860 /* Return most recent version instead of default version for
861 unversioned lookup. */
862 DL_LOOKUP_RETURN_NEWEST
= 2
865 /* Lookup versioned symbol. */
866 extern lookup_t
_dl_lookup_symbol_x (const char *undef
,
867 struct link_map
*undef_map
,
868 const ElfW(Sym
) **sym
,
869 struct r_scope_elem
*symbol_scope
[],
870 const struct r_found_version
*version
,
871 int type_class
, int explicit,
872 struct link_map
*skip_map
)
873 internal_function attribute_hidden
;
876 /* Look up symbol NAME in MAP's scope and return its run-time address. */
877 extern ElfW(Addr
) _dl_symbol_value (struct link_map
*map
, const char *name
)
880 /* Allocate a `struct link_map' for a new object being loaded,
881 and enter it into the _dl_main_map list. */
882 extern struct link_map
*_dl_new_object (char *realname
, const char *libname
,
883 int type
, struct link_map
*loader
,
884 int mode
, Lmid_t nsid
)
885 internal_function attribute_hidden
;
887 /* Relocate the given object (if it hasn't already been).
888 SCOPE is passed to _dl_lookup_symbol in symbol lookups.
889 If LAZY is nonzero, don't relocate its PLT. */
890 extern void _dl_relocate_object (struct link_map
*map
,
891 struct r_scope_elem
*scope
[],
892 int lazy
, int consider_profiling
)
895 /* Protect PT_GNU_RELRO area. */
896 extern void _dl_protect_relro (struct link_map
*map
)
897 internal_function attribute_hidden
;
899 /* Call _dl_signal_error with a message about an unhandled reloc type.
900 TYPE is the result of ELFW(R_TYPE) (r_info), i.e. an R_<CPU>_* value.
901 PLT is nonzero if this was a PLT reloc; it just affects the message. */
902 extern void _dl_reloc_bad_type (struct link_map
*map
,
903 unsigned int type
, int plt
)
904 internal_function
__attribute__ ((__noreturn__
));
906 /* Resolve conflicts if prelinking. */
907 extern void _dl_resolve_conflicts (struct link_map
*l
,
908 ElfW(Rela
) *conflict
,
909 ElfW(Rela
) *conflictend
);
911 /* Check the version dependencies of all objects available through
912 MAP. If VERBOSE print some more diagnostics. */
913 extern int _dl_check_all_versions (struct link_map
*map
, int verbose
,
917 /* Check the version dependencies for MAP. If VERBOSE print some more
919 extern int _dl_check_map_versions (struct link_map
*map
, int verbose
,
923 /* Initialize the object in SCOPE by calling the constructors with
924 ARGC, ARGV, and ENV as the parameters. */
925 extern void _dl_init (struct link_map
*main_map
, int argc
, char **argv
,
926 char **env
) internal_function attribute_hidden
;
928 /* Call the finalizer functions of all shared objects whose
929 initializer functions have completed. */
930 extern void _dl_fini (void) internal_function
;
932 /* Sort array MAPS according to dependencies of the contained objects. */
933 extern void _dl_sort_fini (struct link_map
*l
, struct link_map
**maps
,
934 size_t nmaps
, char *used
, Lmid_t ns
)
937 /* The dynamic linker calls this function before and having changing
938 any shared object mappings. The `r_state' member of `struct r_debug'
939 says what change is taking place. This function's address is
940 the value of the `r_brk' member. */
941 extern void _dl_debug_state (void);
942 rtld_hidden_proto (_dl_debug_state
)
944 /* Initialize `struct r_debug' if it has not already been done. The
945 argument is the run-time load address of the dynamic linker, to be put
946 in the `r_ldbase' member. Returns the address of the structure. */
947 extern struct r_debug
*_dl_debug_initialize (ElfW(Addr
) ldbase
, Lmid_t ns
)
950 /* Initialize the basic data structure for the search paths. */
951 extern void _dl_init_paths (const char *library_path
) internal_function
;
953 /* Gather the information needed to install the profiling tables and start
955 extern void _dl_start_profile (void) internal_function attribute_hidden
;
957 /* The actual functions used to keep book on the calls. */
958 extern void _dl_mcount (ElfW(Addr
) frompc
, ElfW(Addr
) selfpc
);
959 extern void _dl_mcount_internal (ElfW(Addr
) frompc
, ElfW(Addr
) selfpc
)
962 /* This function is simply a wrapper around the _dl_mcount function
963 which does not require a FROMPC parameter since this is the
965 extern void _dl_mcount_wrapper (void *selfpc
);
967 /* Show the members of the auxiliary array passed up from the kernel. */
968 extern void _dl_show_auxv (void) internal_function
;
970 /* Return all environment variables starting with `LD_', one after the
972 extern char *_dl_next_ld_env_entry (char ***position
) internal_function
;
974 /* Return an array with the names of the important hardware capabilities. */
975 extern const struct r_strlenpair
*_dl_important_hwcaps (const char *platform
,
978 size_t *max_capstrlen
)
981 /* Look up NAME in ld.so.cache and return the file name stored there,
982 or null if none is found. */
983 extern const char *_dl_load_cache_lookup (const char *name
)
986 /* If the system does not support MAP_COPY we cannot leave the file open
987 all the time since this would create problems when the file is replaced.
988 Therefore we provide this function to close the file and open it again
990 extern void _dl_unload_cache (void) attribute_hidden
;
992 /* System-dependent function to read a file's whole contents in the
993 most convenient manner available. *SIZEP gets the size of the
994 file. On error MAP_FAILED is returned. */
995 extern void *_dl_sysdep_read_whole_file (const char *file
, size_t *sizep
,
997 internal_function attribute_hidden
;
999 /* System-specific function to do initial startup for the dynamic linker.
1000 After this, file access calls and getenv must work. This is responsible
1001 for setting __libc_enable_secure if we need to be secure (e.g. setuid),
1002 and for setting _dl_argc and _dl_argv, and then calling _dl_main. */
1003 extern ElfW(Addr
) _dl_sysdep_start (void **start_argptr
,
1004 void (*dl_main
) (const ElfW(Phdr
) *phdr
,
1006 ElfW(Addr
) *user_entry
))
1009 extern void _dl_sysdep_start_cleanup (void)
1010 internal_function attribute_hidden
;
1013 /* Determine next available module ID. */
1014 extern size_t _dl_next_tls_modid (void) internal_function attribute_hidden
;
1016 /* Calculate offset of the TLS blocks in the static TLS block. */
1017 extern void _dl_determine_tlsoffset (void) internal_function attribute_hidden
;
1019 /* Set up the data structures for TLS, when they were not set up at startup.
1020 Returns nonzero on malloc failure.
1021 This is called from _dl_map_object_from_fd or by libpthread. */
1022 extern int _dl_tls_setup (void) internal_function
;
1023 rtld_hidden_proto (_dl_tls_setup
)
1025 /* Allocate memory for static TLS block (unless MEM is nonzero) and dtv. */
1026 extern void *_dl_allocate_tls (void *mem
) internal_function
;
1027 rtld_hidden_proto (_dl_allocate_tls
)
1029 /* Get size and alignment requirements of the static TLS block. */
1030 extern void _dl_get_tls_static_info (size_t *sizep
, size_t *alignp
)
1033 extern void _dl_allocate_static_tls (struct link_map
*map
)
1034 internal_function attribute_hidden
;
1036 /* These are internal entry points to the two halves of _dl_allocate_tls,
1037 only used within rtld.c itself at startup time. */
1038 extern void *_dl_allocate_tls_storage (void)
1039 internal_function attribute_hidden
;
1040 extern void *_dl_allocate_tls_init (void *) internal_function
;
1041 rtld_hidden_proto (_dl_allocate_tls_init
)
1043 /* Deallocate memory allocated with _dl_allocate_tls. */
1044 extern void _dl_deallocate_tls (void *tcb
, bool dealloc_tcb
) internal_function
;
1045 rtld_hidden_proto (_dl_deallocate_tls
)
1048 extern void _dl_nothread_init_static_tls (struct link_map
*) attribute_hidden
;
1051 /* Find origin of the executable. */
1052 extern const char *_dl_get_origin (void) attribute_hidden
;
1055 extern size_t _dl_dst_count (const char *name
, int is_path
) attribute_hidden
;
1057 /* Substitute DST values. */
1058 extern char *_dl_dst_substitute (struct link_map
*l
, const char *name
,
1059 char *result
, int is_path
) attribute_hidden
;
1061 /* Check validity of the caller. */
1062 extern int _dl_check_caller (const void *caller
, enum allowmask mask
)
1065 /* Open the shared object NAME, relocate it, and run its initializer if it
1066 hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If
1067 the object is already opened, returns its existing map. */
1068 extern void *_dl_open (const char *name
, int mode
, const void *caller
,
1069 Lmid_t nsid
, int argc
, char *argv
[], char *env
[])
1072 /* Free or queue for freeing scope OLD. If other threads might be
1073 in the middle of _dl_fixup, _dl_profile_fixup or dl*sym using the
1074 old scope, OLD can't be freed until no thread is using it. */
1075 extern int _dl_scope_free (struct r_scope_elem
**old
) attribute_hidden
;
1077 /* Add module to slot information data. */
1078 extern void _dl_add_to_slotinfo (struct link_map
*l
) attribute_hidden
;
1080 /* Update slot information data for at least the generation of the
1081 module with the given index. */
1082 extern struct link_map
*_dl_update_slotinfo (unsigned long int req_modid
);
1084 /* Look up the module's TLS block as for __tls_get_addr,
1085 but never touch anything. Return null if it's not allocated yet. */
1086 extern void *_dl_tls_get_addr_soft (struct link_map
*l
) internal_function
;
1088 extern int _dl_addr_inside_object (struct link_map
*l
, const ElfW(Addr
) addr
)
1089 internal_function attribute_hidden
;
1093 #endif /* ldsodefs.h */