1 /* Run-time dynamic linker data structures for loaded ELF shared objects.
2 Copyright (C) 1995-2006, 2007, 2008, 2009 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>
41 #include <kernel-features.h>
45 /* We use this macro to refer to ELF types independent of the native wordsize.
46 `ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'. */
47 #define ELFW(type) _ElfW (ELF, __ELF_NATIVE_CLASS, type)
49 /* All references to the value of l_info[DT_PLTGOT],
50 l_info[DT_STRTAB], l_info[DT_SYMTAB], l_info[DT_RELA],
51 l_info[DT_REL], l_info[DT_JMPREL], and l_info[VERSYMIDX (DT_VERSYM)]
52 have to be accessed via the D_PTR macro. The macro is needed since for
53 most architectures the entry is already relocated - but for some not
54 and we need to relocate at access time. */
55 #ifdef DL_RO_DYN_SECTION
56 # define D_PTR(map, i) ((map)->i->d_un.d_ptr + (map)->l_addr)
58 # define D_PTR(map, i) (map)->i->d_un.d_ptr
61 /* Result of the lookup functions and how to retrieve the base address. */
62 typedef struct link_map
*lookup_t
;
63 #define LOOKUP_VALUE(map) map
64 #define LOOKUP_VALUE_ADDRESS(map) ((map) ? (map)->l_addr : 0)
66 /* On some architectures a pointer to a function is not just a pointer
67 to the actual code of the function but rather an architecture
68 specific descriptor. */
69 #ifndef ELF_FUNCTION_PTR_IS_SPECIAL
70 # define DL_SYMBOL_ADDRESS(map, ref) \
71 (void *) (LOOKUP_VALUE_ADDRESS (map) + ref->st_value)
72 # define DL_LOOKUP_ADDRESS(addr) ((ElfW(Addr)) (addr))
73 # define DL_DT_INIT_ADDRESS(map, start) (start)
74 # define DL_DT_FINI_ADDRESS(map, start) (start)
77 /* On some architectures dladdr can't use st_size of all symbols this way. */
78 #define DL_ADDR_SYM_MATCH(L, SYM, MATCHSYM, ADDR) \
79 ((ADDR) >= (L)->l_addr + (SYM)->st_value \
80 && ((((SYM)->st_shndx == SHN_UNDEF || (SYM)->st_size == 0) \
81 && (ADDR) == (L)->l_addr + (SYM)->st_value) \
82 || (ADDR) < (L)->l_addr + (SYM)->st_value + (SYM)->st_size) \
83 && ((MATCHSYM) == NULL || (MATCHSYM)->st_value < (SYM)->st_value))
85 /* Unmap a loaded object, called by _dl_close (). */
86 #ifndef DL_UNMAP_IS_SPECIAL
87 # define DL_UNMAP(map) \
88 __munmap ((void *) (map)->l_map_start, \
89 (map)->l_map_end - (map)->l_map_start)
92 /* By default we do not need special support to initialize DSOs loaded
93 by statically linked binaries. */
94 #ifndef DL_STATIC_INIT
95 # define DL_STATIC_INIT(map)
98 /* Reloc type classes as returned by elf_machine_type_class().
99 ELF_RTYPE_CLASS_PLT means this reloc should not be satisfied by
100 some PLT symbol, ELF_RTYPE_CLASS_COPY means this reloc should not be
101 satisfied by any symbol in the executable. Some architectures do
102 not support copy relocations. In this case we define the macro to
103 zero so that the code for handling them gets automatically optimized
105 #define ELF_RTYPE_CLASS_PLT 1
106 #ifndef DL_NO_COPY_RELOCS
107 # define ELF_RTYPE_CLASS_COPY 2
109 # define ELF_RTYPE_CLASS_COPY 0
112 /* ELF uses the PF_x macros to specify the segment permissions, mmap
113 uses PROT_xxx. In most cases the three macros have the values 1, 2,
114 and 3 but not in a matching order. The following macros allows
115 converting from the PF_x values to PROT_xxx values. */
117 ((PROT_READ << (PF_R * 4)) \
118 | (PROT_WRITE << (PF_W * 4)) \
119 | (PROT_EXEC << (PF_X * 4)) \
120 | ((PROT_READ | PROT_WRITE) << ((PF_R | PF_W) * 4)) \
121 | ((PROT_READ | PROT_EXEC) << ((PF_R | PF_X) * 4)) \
122 | ((PROT_WRITE | PROT_EXEC) << (PF_W | PF_X) * 4) \
123 | ((PROT_READ | PROT_WRITE | PROT_EXEC) << ((PF_R | PF_W | PF_X) * 4)))
126 /* For the version handling we need an array with only names and their
128 struct r_found_version
134 const char *filename
;
137 /* We want to cache information about the searches for shared objects. */
139 enum r_dir_status
{ unknown
, nonexisting
, existing
};
141 struct r_search_path_elem
143 /* This link is only used in the `all_dirs' member of `r_search_path'. */
144 struct r_search_path_elem
*next
;
146 /* Strings saying where the definition came from. */
150 /* Basename for this search path element. The string must end with
151 a slash character. */
155 enum r_dir_status status
[0];
165 /* A data structure for a simple single linked list of strings. */
168 const char *name
; /* Name requested (before search). */
169 struct libname_list
*next
; /* Link to next name for this object. */
170 int dont_free
; /* Flag whether this element should be freed
171 if the object is not entirely unloaded. */
175 /* Bit masks for the objects which valid callers can come from to
176 functions with restricted interface. */
181 allow_libpthread
= 4,
186 /* Type for list of auditing interfaces. */
188 struct La_i86_retval
;
189 struct La_x86_64_regs
;
190 struct La_x86_64_retval
;
191 struct La_ppc32_regs
;
192 struct La_ppc32_retval
;
193 struct La_ppc64_regs
;
194 struct La_ppc64_retval
;
197 struct La_alpha_regs
;
198 struct La_alpha_retval
;
199 struct La_s390_32_regs
;
200 struct La_s390_32_retval
;
201 struct La_s390_64_regs
;
202 struct La_s390_64_retval
;
204 struct La_ia64_retval
;
205 struct La_sparc32_regs
;
206 struct La_sparc32_retval
;
207 struct La_sparc64_regs
;
208 struct La_sparc64_retval
;
212 void (*activity
) (uintptr_t *, unsigned int);
213 char *(*objsearch
) (const char *, uintptr_t *, unsigned int);
214 unsigned int (*objopen
) (struct link_map
*, Lmid_t
, uintptr_t *);
215 void (*preinit
) (uintptr_t *);
218 uintptr_t (*symbind32
) (Elf32_Sym
*, unsigned int, uintptr_t *,
219 uintptr_t *, unsigned int *, const char *);
220 uintptr_t (*symbind64
) (Elf64_Sym
*, unsigned int, uintptr_t *,
221 uintptr_t *, unsigned int *, const char *);
225 Elf32_Addr (*i86_gnu_pltenter
) (Elf32_Sym
*, unsigned int, uintptr_t *,
226 uintptr_t *, struct La_i86_regs
*,
227 unsigned int *, const char *name
,
228 long int *framesizep
);
229 Elf64_Addr (*x86_64_gnu_pltenter
) (Elf64_Sym
*, unsigned int, uintptr_t *,
230 uintptr_t *, struct La_x86_64_regs
*,
231 unsigned int *, const char *name
,
232 long int *framesizep
);
233 Elf32_Addr (*ppc32_gnu_pltenter
) (Elf32_Sym
*, unsigned int, uintptr_t *,
234 uintptr_t *, struct La_ppc32_regs
*,
235 unsigned int *, const char *name
,
236 long int *framesizep
);
237 Elf64_Addr (*ppc64_gnu_pltenter
) (Elf64_Sym
*, unsigned int, uintptr_t *,
238 uintptr_t *, struct La_ppc64_regs
*,
239 unsigned int *, const char *name
,
240 long int *framesizep
);
241 uintptr_t (*sh_gnu_pltenter
) (Elf32_Sym
*, unsigned int, uintptr_t *,
242 uintptr_t *, const struct La_sh_regs
*,
243 unsigned int *, const char *name
,
244 long int *framesizep
);
245 Elf64_Addr (*alpha_gnu_pltenter
) (Elf64_Sym
*, unsigned int, uintptr_t *,
246 uintptr_t *, struct La_alpha_regs
*,
247 unsigned int *, const char *name
,
248 long int *framesizep
);
249 Elf32_Addr (*s390_32_gnu_pltenter
) (Elf32_Sym
*, unsigned int, uintptr_t *,
250 uintptr_t *, struct La_s390_32_regs
*,
251 unsigned int *, const char *name
,
252 long int *framesizep
);
253 Elf64_Addr (*s390_64_gnu_pltenter
) (Elf64_Sym
*, unsigned int, uintptr_t *,
254 uintptr_t *, struct La_s390_64_regs
*,
255 unsigned int *, const char *name
,
256 long int *framesizep
);
257 Elf64_Addr (*ia64_gnu_pltenter
) (Elf64_Sym
*, unsigned int, uintptr_t *,
258 uintptr_t *, struct La_ia64_regs
*,
259 unsigned int *, const char *name
,
260 long int *framesizep
);
261 Elf32_Addr (*sparc32_gnu_pltenter
) (Elf32_Sym
*, unsigned int,
262 uintptr_t *, uintptr_t *,
263 const struct La_sparc32_regs
*,
264 unsigned int *, const char *name
,
265 long int *framesizep
);
266 Elf64_Addr (*sparc64_gnu_pltenter
) (Elf64_Sym
*, unsigned int,
267 uintptr_t *, uintptr_t *,
268 const struct La_sparc64_regs
*,
269 unsigned int *, const char *name
,
270 long int *framesizep
);
271 #ifdef ARCH_PLTENTER_MEMBERS
272 ARCH_PLTENTER_MEMBERS
;
277 unsigned int (*i86_gnu_pltexit
) (Elf32_Sym
*, unsigned int, uintptr_t *,
278 uintptr_t *, const struct La_i86_regs
*,
279 struct La_i86_retval
*, const char *);
280 unsigned int (*x86_64_gnu_pltexit
) (Elf64_Sym
*, unsigned int, uintptr_t *,
282 const struct La_x86_64_regs
*,
283 struct La_x86_64_retval
*,
285 unsigned int (*ppc32_gnu_pltexit
) (Elf32_Sym
*, unsigned int, uintptr_t *,
287 const struct La_ppc32_regs
*,
288 struct La_ppc32_retval
*, const char *);
289 unsigned int (*ppc64_gnu_pltexit
) (Elf64_Sym
*, unsigned int, uintptr_t *,
291 const struct La_ppc64_regs
*,
292 struct La_ppc64_retval
*, const char *);
293 unsigned int (*sh_gnu_pltexit
) (Elf32_Sym
*, unsigned int, uintptr_t *,
294 uintptr_t *, const struct La_sh_regs
*,
295 struct La_sh_retval
*, const char *);
296 unsigned int (*alpha_gnu_pltexit
) (Elf64_Sym
*, unsigned int, uintptr_t *,
298 const struct La_alpha_regs
*,
299 struct La_alpha_retval
*, const char *);
300 unsigned int (*s390_32_gnu_pltexit
) (Elf32_Sym
*, unsigned int,
301 uintptr_t *, uintptr_t *,
302 const struct La_s390_32_regs
*,
303 struct La_s390_32_retval
*,
305 unsigned int (*s390_64_gnu_pltexit
) (Elf64_Sym
*, unsigned int,
306 uintptr_t *, uintptr_t *,
307 const struct La_s390_64_regs
*,
308 struct La_s390_64_retval
*,
310 unsigned int (*ia64_gnu_pltexit
) (Elf64_Sym
*, unsigned int, uintptr_t *,
312 const struct La_ia64_regs
*,
313 struct La_ia64_retval
*, const char *);
314 unsigned int (*sparc32_gnu_pltexit
) (Elf32_Sym
*, unsigned int,
315 uintptr_t *, uintptr_t *,
316 const struct La_sparc32_regs
*,
317 struct La_sparc32_retval
*,
319 unsigned int (*sparc64_gnu_pltexit
) (Elf64_Sym
*, unsigned int,
320 uintptr_t *, uintptr_t *,
321 const struct La_sparc32_regs
*,
322 struct La_sparc32_retval
*,
324 #ifdef ARCH_PLTEXIT_MEMBERS
325 ARCH_PLTEXIT_MEMBERS
;
328 unsigned int (*objclose
) (uintptr_t *);
330 struct audit_ifaces
*next
;
334 /* Test whether given NAME matches any of the names of the given object. */
335 extern int _dl_name_match_p (const char *__name
, const struct link_map
*__map
)
338 /* Function used as argument for `_dl_receive_error' function. The
339 arguments are the error code, error string, and the objname the
340 error occurred in. */
341 typedef void (*receiver_fct
) (int, const char *, const char *);
343 /* Internal functions of the run-time dynamic linker.
344 These can be accessed if you link again the dynamic linker
345 as a shared library, as in `-lld' or `/lib/ld.so' explicitly;
346 but are not normally of interest to user programs.
348 The `-ldl' library functions in <dlfcn.h> provide a simple
349 user interface to run-time dynamic linking. */
353 # define EXTERN extern
354 # define GL(name) _##name
358 # define GL(name) _rtld_local._##name
360 # define GL(name) _rtld_global._##name
365 /* Don't change the order of the following elements. 'dl_loaded'
366 must remain the first element. Forever. */
368 /* Non-shared code has no support for multiple namespaces. */
374 EXTERN
struct link_namespaces
376 /* A pointer to the map for the main map. */
377 struct link_map
*_ns_loaded
;
378 /* Number of object in the _dl_loaded list. */
379 unsigned int _ns_nloaded
;
380 /* Direct pointer to the searchlist of the main object. */
381 struct r_scope_elem
*_ns_main_searchlist
;
382 /* This is zero at program start to signal that the global scope map is
383 allocated by rtld. Later it keeps the size of the map. It might be
384 reset if in _dl_close if the last global object is removed. */
385 size_t _ns_global_scope_alloc
;
386 /* Keep track of changes to each namespace' list. */
387 struct r_debug _ns_debug
;
389 /* One higher than index of last used namespace. */
390 EXTERN
size_t _dl_nns
;
392 /* During the program run we must not modify the global data of
393 loaded shared object simultanously in two threads. Therefore we
394 protect `_dl_open' and `_dl_close' in dl-close.c.
396 This must be a recursive lock since the initializer function of
397 the loaded object might as well require a call to this function.
398 At this time it is not anymore a problem to modify the tables. */
399 __rtld_lock_define_recursive (EXTERN
, _dl_load_lock
)
401 /* Incremented whenever something may have been added to dl_loaded. */
402 EXTERN
unsigned long long _dl_load_adds
;
404 /* The object to be initialized first. */
405 EXTERN
struct link_map
*_dl_initfirst
;
407 #if HP_TIMING_AVAIL || HP_SMALL_TIMING_AVAIL
408 /* Start time on CPU clock. */
409 EXTERN hp_timing_t _dl_cpuclock_offset
;
412 /* Map of shared object to be profiled. */
413 EXTERN
struct link_map
*_dl_profile_map
;
415 /* Counters for the number of relocations performed. */
416 EXTERN
unsigned long int _dl_num_relocations
;
417 EXTERN
unsigned long int _dl_num_cache_relocations
;
419 /* List of search directories. */
420 EXTERN
struct r_search_path_elem
*_dl_all_dirs
;
422 #ifdef _LIBC_REENTRANT
423 EXTERN
void **(*_dl_error_catch_tsd
) (void) __attribute__ ((const));
426 /* Structure describing the dynamic linker itself. We need to
427 reserve memory for the data the audit libraries need. */
428 EXTERN
struct link_map _dl_rtld_map
;
430 struct auditstate audit_data
[DL_NNS
];
433 #if defined SHARED && defined _LIBC_REENTRANT \
434 && defined __rtld_lock_default_lock_recursive
435 EXTERN
void (*_dl_rtld_lock_recursive
) (void *);
436 EXTERN
void (*_dl_rtld_unlock_recursive
) (void *);
439 /* If loading a shared object requires that we make the stack executable
440 when it was not, we do it by calling this function.
441 It returns an errno code or zero on success. */
442 EXTERN
int (*_dl_make_stack_executable_hook
) (void **) internal_function
;
444 /* Prevailing state of the stack, PF_X indicating it's executable. */
445 EXTERN
ElfW(Word
) _dl_stack_flags
;
447 /* Flag signalling whether there are gaps in the module ID allocation. */
448 EXTERN
bool _dl_tls_dtv_gaps
;
449 /* Highest dtv index currently needed. */
450 EXTERN
size_t _dl_tls_max_dtv_idx
;
451 /* Information about the dtv slots. */
452 EXTERN
struct dtv_slotinfo_list
455 struct dtv_slotinfo_list
*next
;
459 struct link_map
*map
;
461 } *_dl_tls_dtv_slotinfo_list
;
462 /* Number of modules in the static TLS block. */
463 EXTERN
size_t _dl_tls_static_nelem
;
464 /* Size of the static TLS block. */
465 EXTERN
size_t _dl_tls_static_size
;
466 /* Size actually allocated in the static TLS block. */
467 EXTERN
size_t _dl_tls_static_used
;
468 /* Alignment requirement of the static TLS block. */
469 EXTERN
size_t _dl_tls_static_align
;
471 /* Number of additional entries in the slotinfo array of each slotinfo
472 list element. A large number makes it almost certain take we never
473 have to iterate beyond the first element in the slotinfo list. */
474 #define TLS_SLOTINFO_SURPLUS (62)
476 /* Number of additional slots in the dtv allocated. */
477 #define DTV_SURPLUS (14)
479 /* Initial dtv of the main thread, not allocated with normal malloc. */
480 EXTERN
void *_dl_initial_dtv
;
481 /* Generation counter for the dtv. */
482 EXTERN
size_t _dl_tls_generation
;
484 EXTERN
void (*_dl_init_static_tls
) (struct link_map
*);
486 EXTERN
void (*_dl_wait_lookup_done
) (void);
488 /* Scopes to free after next THREAD_GSCOPE_WAIT (). */
489 EXTERN
struct dl_scope_free_list
493 } *_dl_scope_free_list
;
496 # define __rtld_global_attribute__
498 # ifdef HAVE_SDATA_SECTION
499 # define __rtld_local_attribute__ \
500 __attribute__ ((visibility ("hidden"), section (".sdata")))
501 # undef __rtld_global_attribute__
502 # define __rtld_global_attribute__ __attribute__ ((section (".sdata")))
504 # define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
506 extern struct rtld_global _rtld_local __rtld_local_attribute__
;
507 # undef __rtld_local_attribute__
509 extern struct rtld_global _rtld_global __rtld_global_attribute__
;
510 # undef __rtld_global_attribute__
514 # define GLRO(name) _##name
517 # define GLRO(name) _rtld_local_ro._##name
519 # define GLRO(name) _rtld_global_ro._##name
521 struct rtld_global_ro
525 /* If nonzero the appropriate debug information is printed. */
526 EXTERN
int _dl_debug_mask
;
527 #define DL_DEBUG_LIBS (1 << 0)
528 #define DL_DEBUG_IMPCALLS (1 << 1)
529 #define DL_DEBUG_BINDINGS (1 << 2)
530 #define DL_DEBUG_SYMBOLS (1 << 3)
531 #define DL_DEBUG_VERSIONS (1 << 4)
532 #define DL_DEBUG_RELOC (1 << 5)
533 #define DL_DEBUG_FILES (1 << 6)
534 #define DL_DEBUG_STATISTICS (1 << 7)
535 #define DL_DEBUG_UNUSED (1 << 8)
536 /* These two are used only internally. */
537 #define DL_DEBUG_HELP (1 << 9)
538 #define DL_DEBUG_PRELINK (1 << 10)
541 EXTERN
unsigned int _dl_osversion
;
543 EXTERN
const char *_dl_platform
;
544 EXTERN
size_t _dl_platformlen
;
546 /* Cached value of `getpagesize ()'. */
547 EXTERN
size_t _dl_pagesize
;
549 /* Copy of the content of `_dl_main_searchlist' at startup time. */
550 EXTERN
struct r_scope_elem _dl_initial_searchlist
;
552 /* CLK_TCK as reported by the kernel. */
553 EXTERN
int _dl_clktck
;
555 /* If nonzero print warnings messages. */
556 EXTERN
int _dl_verbose
;
558 /* File descriptor to write debug messages to. */
559 EXTERN
int _dl_debug_fd
;
561 /* Do we do lazy relocations? */
564 /* Nonzero if runtime lookups should not update the .got/.plt. */
565 EXTERN
int _dl_bind_not
;
567 /* Nonzero if references should be treated as weak during runtime
569 EXTERN
int _dl_dynamic_weak
;
571 /* Default floating-point control word. */
572 EXTERN fpu_control_t _dl_fpu_control
;
574 /* Expected cache ID. */
575 EXTERN
int _dl_correct_cache_id
;
577 /* Mask for hardware capabilities that are available. */
578 EXTERN
uint64_t _dl_hwcap
;
580 /* Mask for important hardware capabilities we honour. */
581 EXTERN
uint64_t _dl_hwcap_mask
;
583 /* Get architecture specific definitions. */
584 #define PROCINFO_DECL
585 #ifndef PROCINFO_CLASS
586 # define PROCINFO_CLASS EXTERN
588 #include <dl-procinfo.c>
590 /* Names of shared object for which the RPATH should be ignored. */
591 EXTERN
const char *_dl_inhibit_rpath
;
593 /* Location of the binary. */
594 EXTERN
const char *_dl_origin_path
;
596 /* -1 if the dynamic linker should honor library load bias,
597 0 if not, -2 use the default (honor biases for normal
598 binaries, don't honor for PIEs). */
599 EXTERN
ElfW(Addr
) _dl_use_load_bias
;
601 /* Name of the shared object to be profiled (if any). */
602 EXTERN
const char *_dl_profile
;
603 /* Filename of the output file. */
604 EXTERN
const char *_dl_profile_output
;
605 /* Name of the object we want to trace the prelinking. */
606 EXTERN
const char *_dl_trace_prelink
;
607 /* Map of shared object to be prelink traced. */
608 EXTERN
struct link_map
*_dl_trace_prelink_map
;
610 /* All search directories defined at startup. */
611 EXTERN
struct r_search_path_elem
*_dl_init_all_dirs
;
613 #if HP_TIMING_AVAIL || HP_SMALL_TIMING_AVAIL
614 /* Overhead of a high-precision timing measurement. */
615 EXTERN hp_timing_t _dl_hp_timing_overhead
;
618 #ifdef NEED_DL_SYSINFO
619 /* Syscall handling improvements. This is very specific to x86. */
620 EXTERN
uintptr_t _dl_sysinfo
;
623 #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
624 /* The vsyscall page is a virtual DSO pre-mapped by the kernel.
625 This points to its ELF header. */
626 EXTERN
const ElfW(Ehdr
) *_dl_sysinfo_dso
;
628 /* At startup time we set up the normal DSO data structure for it,
629 and this points to it. */
630 EXTERN
struct link_map
*_dl_sysinfo_map
;
634 /* We add a function table to _rtld_global which is then used to
635 call the function instead of going through the PLT. The result
636 is that we can avoid exporting the functions and we do not jump
637 PLT relocations in libc.so. */
638 void (*_dl_debug_printf
) (const char *, ...)
639 __attribute__ ((__format__ (__printf__
, 1, 2)));
640 int (internal_function
*_dl_catch_error
) (const char **, const char **,
641 bool *, void (*) (void *), void *);
642 void (internal_function
*_dl_signal_error
) (int, const char *, const char *,
644 void (*_dl_mcount
) (ElfW(Addr
) frompc
, ElfW(Addr
) selfpc
);
645 lookup_t (internal_function
*_dl_lookup_symbol_x
) (const char *,
648 struct r_scope_elem
*[],
649 const struct r_found_version
*,
652 int (*_dl_check_caller
) (const void *, enum allowmask
);
653 void *(*_dl_open
) (const char *file
, int mode
, const void *caller_dlopen
,
654 Lmid_t nsid
, int argc
, char *argv
[], char *env
[]);
655 void (*_dl_close
) (void *map
);
656 void *(*_dl_tls_get_addr_soft
) (struct link_map
*);
657 #ifdef HAVE_DL_DISCOVER_OSVERSION
658 int (*_dl_discover_osversion
) (void);
661 /* List of auditing interfaces. */
662 struct audit_ifaces
*_dl_audit
;
663 unsigned int _dl_naudit
;
665 /* 0 if internal pointer values should not be guarded, 1 if they should. */
666 EXTERN
int _dl_pointer_guard
;
668 # define __rtld_global_attribute__
670 # define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
671 extern struct rtld_global_ro _rtld_local_ro
672 attribute_relro __rtld_local_attribute__
;
673 extern struct rtld_global_ro _rtld_global_ro
674 attribute_relro __rtld_global_attribute__
;
675 # undef __rtld_local_attribute__
677 /* We cheat a bit here. We declare the variable as as const even
678 though it is at startup. */
679 extern const struct rtld_global_ro _rtld_global_ro
680 attribute_relro __rtld_global_attribute__
;
682 # undef __rtld_global_attribute__
687 /* This is the initial value of GL(dl_error_catch_tsd).
688 A non-TLS libpthread will change it. */
689 extern void **_dl_initial_error_catch_tsd (void) __attribute__ ((const))
693 /* This is the initial value of GL(dl_make_stack_executable_hook).
694 A threads library can change it. */
695 extern int _dl_make_stack_executable (void **stack_endp
) internal_function
;
696 rtld_hidden_proto (_dl_make_stack_executable
)
698 /* Variable pointing to the end of the stack (or close to it). This value
699 must be constant over the runtime of the application. Some programs
700 might use the variable which results in copy relocations on some
701 platforms. But this does not matter, ld.so can always use the local
703 extern void *__libc_stack_end attribute_relro
;
704 rtld_hidden_proto (__libc_stack_end
)
706 /* Parameters passed to the dynamic linker. */
707 extern int _dl_argc attribute_hidden attribute_relro
;
708 extern char **_dl_argv
709 #ifndef DL_ARGV_NOT_RELRO
714 extern char **_dl_argv_internal attribute_hidden
715 # ifndef DL_ARGV_NOT_RELRO
719 # define rtld_progname (INTUSE(_dl_argv)[0])
721 # define rtld_progname _dl_argv[0]
724 /* Flag set at startup and cleared when the last initializer has run. */
725 extern int _dl_starting_up
;
726 weak_extern (_dl_starting_up
)
728 extern int _dl_starting_up_internal attribute_hidden
;
731 /* Random data provided by the kernel. */
732 extern void *_dl_random attribute_hidden
;
734 /* OS-dependent function to open the zero-fill device. */
735 extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */
738 /* Write message on the debug file descriptor. The parameters are
739 interpreted as for a `printf' call. All the lines start with a
740 tag showing the PID. */
741 extern void _dl_debug_printf (const char *fmt
, ...)
742 __attribute__ ((__format__ (__printf__
, 1, 2))) attribute_hidden
;
744 /* Write message on the debug file descriptor. The parameters are
745 interpreted as for a `printf' call. All the lines buf the first
746 start with a tag showing the PID. */
747 extern void _dl_debug_printf_c (const char *fmt
, ...)
748 __attribute__ ((__format__ (__printf__
, 1, 2)));
751 /* Write a message on the specified descriptor FD. The parameters are
752 interpreted as for a `printf' call. */
753 extern void _dl_dprintf (int fd
, const char *fmt
, ...)
754 __attribute__ ((__format__ (__printf__
, 2, 3)))
757 /* Write a message on the specified descriptor standard output. The
758 parameters are interpreted as for a `printf' call. */
759 #define _dl_printf(fmt, args...) \
760 _dl_dprintf (STDOUT_FILENO, fmt, ##args)
762 /* Write a message on the specified descriptor standard error. The
763 parameters are interpreted as for a `printf' call. */
764 #define _dl_error_printf(fmt, args...) \
765 _dl_dprintf (STDERR_FILENO, fmt, ##args)
767 /* Write a message on the specified descriptor standard error and exit
768 the program. The parameters are interpreted as for a `printf' call. */
769 #define _dl_fatal_printf(fmt, args...) \
772 _dl_dprintf (STDERR_FILENO, fmt, ##args); \
778 /* This function is called by all the internal dynamic linker functions
779 when they encounter an error. ERRCODE is either an `errno' code or
780 zero; OBJECT is the name of the problematical shared object, or null if
781 it is a general problem; ERRSTRING is a string describing the specific
783 extern void _dl_signal_error (int errcode
, const char *object
,
784 const char *occurred
, const char *errstring
)
785 internal_function
__attribute__ ((__noreturn__
)) attribute_hidden
;
787 /* Like _dl_signal_error, but may return when called in the context of
788 _dl_receive_error. */
789 extern void _dl_signal_cerror (int errcode
, const char *object
,
790 const char *occation
, const char *errstring
)
793 /* Call OPERATE, receiving errors from `dl_signal_cerror'. Unlike
794 `_dl_catch_error' the operation is resumed after the OPERATE
796 ARGS is passed as argument to OPERATE. */
797 extern void _dl_receive_error (receiver_fct fct
, void (*operate
) (void *),
802 /* Open the shared object NAME and map in its segments.
803 LOADER's DT_RPATH is used in searching for NAME.
804 If the object is already opened, returns its existing map.
805 For preloaded shared objects PRELOADED is set to a non-zero
806 value to allow additional security checks. */
807 extern struct link_map
*_dl_map_object (struct link_map
*loader
,
808 const char *name
, int preloaded
,
809 int type
, int trace_mode
, int mode
,
811 internal_function attribute_hidden
;
813 /* Call _dl_map_object on the dependencies of MAP, and set up
814 MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously
815 loaded objects that will be inserted into MAP->l_searchlist after MAP
816 but before its dependencies. */
817 extern void _dl_map_object_deps (struct link_map
*map
,
818 struct link_map
**preloads
,
819 unsigned int npreloads
, int trace_mode
,
821 internal_function attribute_hidden
;
823 /* Cache the locations of MAP's hash table. */
824 extern void _dl_setup_hash (struct link_map
*map
)
825 internal_function attribute_hidden
;
828 /* Collect the directories in the search path for LOADER's dependencies.
829 The data structure is defined in <dlfcn.h>. If COUNTING is true,
830 SI->dls_cnt and SI->dls_size are set; if false, those must be as set
831 by a previous call with COUNTING set, and SI must point to SI->dls_size
832 bytes to be used in filling in the result. */
833 extern void _dl_rtld_di_serinfo (struct link_map
*loader
,
834 Dl_serinfo
*si
, bool counting
)
838 /* Search loaded objects' symbol tables for a definition of the symbol
839 referred to by UNDEF. *SYM is the symbol table entry containing the
840 reference; it is replaced with the defining symbol, and the base load
841 address of the defining object is returned. SYMBOL_SCOPE is a
842 null-terminated list of object scopes to search; each object's
843 l_searchlist (i.e. the segment of the dependency tree starting at that
844 object) is searched in turn. REFERENCE_NAME should name the object
845 containing the reference; it is used in error messages.
846 TYPE_CLASS describes the type of symbol we are looking for. */
849 /* If necessary add dependency between user and provider object. */
850 DL_LOOKUP_ADD_DEPENDENCY
= 1,
851 /* Return most recent version instead of default version for
852 unversioned lookup. */
853 DL_LOOKUP_RETURN_NEWEST
= 2,
854 /* Set if dl_lookup* called with GSCOPE lock held. */
855 DL_LOOKUP_GSCOPE_LOCK
= 4,
858 /* Lookup versioned symbol. */
859 extern lookup_t
_dl_lookup_symbol_x (const char *undef
,
860 struct link_map
*undef_map
,
861 const ElfW(Sym
) **sym
,
862 struct r_scope_elem
*symbol_scope
[],
863 const struct r_found_version
*version
,
864 int type_class
, int flags
,
865 struct link_map
*skip_map
)
866 internal_function attribute_hidden
;
869 /* Look up symbol NAME in MAP's scope and return its run-time address. */
870 extern ElfW(Addr
) _dl_symbol_value (struct link_map
*map
, const char *name
)
873 /* Allocate a `struct link_map' for a new object being loaded,
874 and enter it into the _dl_main_map list. */
875 extern struct link_map
*_dl_new_object (char *realname
, const char *libname
,
876 int type
, struct link_map
*loader
,
877 int mode
, Lmid_t nsid
)
878 internal_function attribute_hidden
;
880 /* Relocate the given object (if it hasn't already been).
881 SCOPE is passed to _dl_lookup_symbol in symbol lookups.
882 If RTLD_LAZY is set in RELOC-MODE, don't relocate its PLT. */
883 extern void _dl_relocate_object (struct link_map
*map
,
884 struct r_scope_elem
*scope
[],
885 int reloc_mode
, int consider_profiling
)
888 /* Protect PT_GNU_RELRO area. */
889 extern void _dl_protect_relro (struct link_map
*map
)
890 internal_function attribute_hidden
;
892 /* Call _dl_signal_error with a message about an unhandled reloc type.
893 TYPE is the result of ELFW(R_TYPE) (r_info), i.e. an R_<CPU>_* value.
894 PLT is nonzero if this was a PLT reloc; it just affects the message. */
895 extern void _dl_reloc_bad_type (struct link_map
*map
,
896 unsigned int type
, int plt
)
897 internal_function
__attribute__ ((__noreturn__
));
899 /* Resolve conflicts if prelinking. */
900 extern void _dl_resolve_conflicts (struct link_map
*l
,
901 ElfW(Rela
) *conflict
,
902 ElfW(Rela
) *conflictend
);
904 /* Check the version dependencies of all objects available through
905 MAP. If VERBOSE print some more diagnostics. */
906 extern int _dl_check_all_versions (struct link_map
*map
, int verbose
,
910 /* Check the version dependencies for MAP. If VERBOSE print some more
912 extern int _dl_check_map_versions (struct link_map
*map
, int verbose
,
916 /* Initialize the object in SCOPE by calling the constructors with
917 ARGC, ARGV, and ENV as the parameters. */
918 extern void _dl_init (struct link_map
*main_map
, int argc
, char **argv
,
919 char **env
) internal_function attribute_hidden
;
921 /* Call the finalizer functions of all shared objects whose
922 initializer functions have completed. */
923 extern void _dl_fini (void) internal_function
;
925 /* Sort array MAPS according to dependencies of the contained objects. */
926 extern void _dl_sort_fini (struct link_map
*l
, struct link_map
**maps
,
927 size_t nmaps
, char *used
, Lmid_t ns
)
930 /* The dynamic linker calls this function before and having changing
931 any shared object mappings. The `r_state' member of `struct r_debug'
932 says what change is taking place. This function's address is
933 the value of the `r_brk' member. */
934 extern void _dl_debug_state (void);
935 rtld_hidden_proto (_dl_debug_state
)
937 /* Initialize `struct r_debug' if it has not already been done. The
938 argument is the run-time load address of the dynamic linker, to be put
939 in the `r_ldbase' member. Returns the address of the structure. */
940 extern struct r_debug
*_dl_debug_initialize (ElfW(Addr
) ldbase
, Lmid_t ns
)
943 /* Initialize the basic data structure for the search paths. */
944 extern void _dl_init_paths (const char *library_path
) internal_function
;
946 /* Gather the information needed to install the profiling tables and start
948 extern void _dl_start_profile (void) internal_function attribute_hidden
;
950 /* The actual functions used to keep book on the calls. */
951 extern void _dl_mcount (ElfW(Addr
) frompc
, ElfW(Addr
) selfpc
);
952 extern void _dl_mcount_internal (ElfW(Addr
) frompc
, ElfW(Addr
) selfpc
)
955 /* This function is simply a wrapper around the _dl_mcount function
956 which does not require a FROMPC parameter since this is the
958 extern void _dl_mcount_wrapper (void *selfpc
);
960 /* Show the members of the auxiliary array passed up from the kernel. */
961 extern void _dl_show_auxv (void) internal_function
;
963 /* Return all environment variables starting with `LD_', one after the
965 extern char *_dl_next_ld_env_entry (char ***position
) internal_function
;
967 /* Return an array with the names of the important hardware capabilities. */
968 extern const struct r_strlenpair
*_dl_important_hwcaps (const char *platform
,
971 size_t *max_capstrlen
)
974 /* Look up NAME in ld.so.cache and return the file name stored there,
975 or null if none is found. */
976 extern const char *_dl_load_cache_lookup (const char *name
)
979 /* If the system does not support MAP_COPY we cannot leave the file open
980 all the time since this would create problems when the file is replaced.
981 Therefore we provide this function to close the file and open it again
983 extern void _dl_unload_cache (void) attribute_hidden
;
985 /* System-dependent function to read a file's whole contents in the
986 most convenient manner available. *SIZEP gets the size of the
987 file. On error MAP_FAILED is returned. */
988 extern void *_dl_sysdep_read_whole_file (const char *file
, size_t *sizep
,
990 internal_function attribute_hidden
;
992 /* System-specific function to do initial startup for the dynamic linker.
993 After this, file access calls and getenv must work. This is responsible
994 for setting __libc_enable_secure if we need to be secure (e.g. setuid),
995 and for setting _dl_argc and _dl_argv, and then calling _dl_main. */
996 extern ElfW(Addr
) _dl_sysdep_start (void **start_argptr
,
997 void (*dl_main
) (const ElfW(Phdr
) *phdr
,
999 ElfW(Addr
) *user_entry
))
1002 extern void _dl_sysdep_start_cleanup (void)
1003 internal_function attribute_hidden
;
1006 /* Determine next available module ID. */
1007 extern size_t _dl_next_tls_modid (void) internal_function attribute_hidden
;
1009 /* Calculate offset of the TLS blocks in the static TLS block. */
1010 extern void _dl_determine_tlsoffset (void) internal_function attribute_hidden
;
1012 /* Set up the data structures for TLS, when they were not set up at startup.
1013 Returns nonzero on malloc failure.
1014 This is called from _dl_map_object_from_fd or by libpthread. */
1015 extern int _dl_tls_setup (void) internal_function
;
1016 rtld_hidden_proto (_dl_tls_setup
)
1018 /* Allocate memory for static TLS block (unless MEM is nonzero) and dtv. */
1019 extern void *_dl_allocate_tls (void *mem
) internal_function
;
1020 rtld_hidden_proto (_dl_allocate_tls
)
1022 /* Get size and alignment requirements of the static TLS block. */
1023 extern void _dl_get_tls_static_info (size_t *sizep
, size_t *alignp
)
1026 extern void _dl_allocate_static_tls (struct link_map
*map
)
1027 internal_function attribute_hidden
;
1029 /* These are internal entry points to the two halves of _dl_allocate_tls,
1030 only used within rtld.c itself at startup time. */
1031 extern void *_dl_allocate_tls_storage (void)
1032 internal_function attribute_hidden
;
1033 extern void *_dl_allocate_tls_init (void *) internal_function
;
1034 rtld_hidden_proto (_dl_allocate_tls_init
)
1036 /* Deallocate memory allocated with _dl_allocate_tls. */
1037 extern void _dl_deallocate_tls (void *tcb
, bool dealloc_tcb
) internal_function
;
1038 rtld_hidden_proto (_dl_deallocate_tls
)
1040 extern void _dl_nothread_init_static_tls (struct link_map
*) attribute_hidden
;
1042 /* Find origin of the executable. */
1043 extern const char *_dl_get_origin (void) attribute_hidden
;
1046 extern size_t _dl_dst_count (const char *name
, int is_path
) attribute_hidden
;
1048 /* Substitute DST values. */
1049 extern char *_dl_dst_substitute (struct link_map
*l
, const char *name
,
1050 char *result
, int is_path
) attribute_hidden
;
1052 /* Check validity of the caller. */
1053 extern int _dl_check_caller (const void *caller
, enum allowmask mask
)
1056 /* Open the shared object NAME, relocate it, and run its initializer if it
1057 hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If
1058 the object is already opened, returns its existing map. */
1059 extern void *_dl_open (const char *name
, int mode
, const void *caller
,
1060 Lmid_t nsid
, int argc
, char *argv
[], char *env
[])
1063 /* Free or queue for freeing scope OLD. If other threads might be
1064 in the middle of _dl_fixup, _dl_profile_fixup or dl*sym using the
1065 old scope, OLD can't be freed until no thread is using it. */
1066 extern int _dl_scope_free (void *) attribute_hidden
;
1068 /* Add module to slot information data. */
1069 extern void _dl_add_to_slotinfo (struct link_map
*l
) attribute_hidden
;
1071 /* Update slot information data for at least the generation of the
1072 module with the given index. */
1073 extern struct link_map
*_dl_update_slotinfo (unsigned long int req_modid
);
1075 /* Look up the module's TLS block as for __tls_get_addr,
1076 but never touch anything. Return null if it's not allocated yet. */
1077 extern void *_dl_tls_get_addr_soft (struct link_map
*l
) attribute_hidden
;
1079 extern int _dl_addr_inside_object (struct link_map
*l
, const ElfW(Addr
) addr
)
1080 internal_function attribute_hidden
;
1084 #endif /* ldsodefs.h */