1 /* Run-time dynamic linker data structures for loaded ELF shared objects.
2 Copyright (C) 1995-2009, 2010, 2011 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 /* Compute next higher prime number. */
339 extern unsigned long int _dl_higher_prime_number (unsigned long int n
)
342 /* Function used as argument for `_dl_receive_error' function. The
343 arguments are the error code, error string, and the objname the
344 error occurred in. */
345 typedef void (*receiver_fct
) (int, const char *, const char *);
347 /* Internal functions of the run-time dynamic linker.
348 These can be accessed if you link again the dynamic linker
349 as a shared library, as in `-lld' or `/lib/ld.so' explicitly;
350 but are not normally of interest to user programs.
352 The `-ldl' library functions in <dlfcn.h> provide a simple
353 user interface to run-time dynamic linking. */
357 # define EXTERN extern
358 # define GL(name) _##name
362 # define GL(name) _rtld_local._##name
364 # define GL(name) _rtld_global._##name
369 /* Don't change the order of the following elements. 'dl_loaded'
370 must remain the first element. Forever. */
372 /* Non-shared code has no support for multiple namespaces. */
378 EXTERN
struct link_namespaces
380 /* A pointer to the map for the main map. */
381 struct link_map
*_ns_loaded
;
382 /* Number of object in the _dl_loaded list. */
383 unsigned int _ns_nloaded
;
384 /* Direct pointer to the searchlist of the main object. */
385 struct r_scope_elem
*_ns_main_searchlist
;
386 /* This is zero at program start to signal that the global scope map is
387 allocated by rtld. Later it keeps the size of the map. It might be
388 reset if in _dl_close if the last global object is removed. */
389 size_t _ns_global_scope_alloc
;
390 /* Search table for unique objects. */
391 struct unique_sym_table
393 __rtld_lock_recursive_t lock
;
398 const ElfW(Sym
) *sym
;
399 const struct link_map
*map
;
403 void (*free
) (void *);
404 } _ns_unique_sym_table
;
405 /* Keep track of changes to each namespace' list. */
406 struct r_debug _ns_debug
;
408 /* One higher than index of last used namespace. */
409 EXTERN
size_t _dl_nns
;
411 /* During the program run we must not modify the global data of
412 loaded shared object simultanously in two threads. Therefore we
413 protect `_dl_open' and `_dl_close' in dl-close.c.
415 This must be a recursive lock since the initializer function of
416 the loaded object might as well require a call to this function.
417 At this time it is not anymore a problem to modify the tables. */
418 __rtld_lock_define_recursive (EXTERN
, _dl_load_lock
)
419 /* This lock is used to keep __dl_iterate_phdr from inspecting the
420 list of loaded objects while an object is added to or removed
422 __rtld_lock_define_recursive (EXTERN
, _dl_load_write_lock
)
424 /* Incremented whenever something may have been added to dl_loaded. */
425 EXTERN
unsigned long long _dl_load_adds
;
427 /* The object to be initialized first. */
428 EXTERN
struct link_map
*_dl_initfirst
;
430 #if HP_TIMING_AVAIL || HP_SMALL_TIMING_AVAIL
431 /* Start time on CPU clock. */
432 EXTERN hp_timing_t _dl_cpuclock_offset
;
435 /* Map of shared object to be profiled. */
436 EXTERN
struct link_map
*_dl_profile_map
;
438 /* Counters for the number of relocations performed. */
439 EXTERN
unsigned long int _dl_num_relocations
;
440 EXTERN
unsigned long int _dl_num_cache_relocations
;
442 /* List of search directories. */
443 EXTERN
struct r_search_path_elem
*_dl_all_dirs
;
445 #ifdef _LIBC_REENTRANT
446 EXTERN
void **(*_dl_error_catch_tsd
) (void) __attribute__ ((const));
449 /* Structure describing the dynamic linker itself. We need to
450 reserve memory for the data the audit libraries need. */
451 EXTERN
struct link_map _dl_rtld_map
;
453 struct auditstate audit_data
[DL_NNS
];
456 #if defined SHARED && defined _LIBC_REENTRANT \
457 && defined __rtld_lock_default_lock_recursive
458 EXTERN
void (*_dl_rtld_lock_recursive
) (void *);
459 EXTERN
void (*_dl_rtld_unlock_recursive
) (void *);
462 /* If loading a shared object requires that we make the stack executable
463 when it was not, we do it by calling this function.
464 It returns an errno code or zero on success. */
465 EXTERN
int (*_dl_make_stack_executable_hook
) (void **) internal_function
;
467 /* Prevailing state of the stack, PF_X indicating it's executable. */
468 EXTERN
ElfW(Word
) _dl_stack_flags
;
470 /* Flag signalling whether there are gaps in the module ID allocation. */
471 EXTERN
bool _dl_tls_dtv_gaps
;
472 /* Highest dtv index currently needed. */
473 EXTERN
size_t _dl_tls_max_dtv_idx
;
474 /* Information about the dtv slots. */
475 EXTERN
struct dtv_slotinfo_list
478 struct dtv_slotinfo_list
*next
;
482 struct link_map
*map
;
484 } *_dl_tls_dtv_slotinfo_list
;
485 /* Number of modules in the static TLS block. */
486 EXTERN
size_t _dl_tls_static_nelem
;
487 /* Size of the static TLS block. */
488 EXTERN
size_t _dl_tls_static_size
;
489 /* Size actually allocated in the static TLS block. */
490 EXTERN
size_t _dl_tls_static_used
;
491 /* Alignment requirement of the static TLS block. */
492 EXTERN
size_t _dl_tls_static_align
;
494 /* Number of additional entries in the slotinfo array of each slotinfo
495 list element. A large number makes it almost certain take we never
496 have to iterate beyond the first element in the slotinfo list. */
497 #define TLS_SLOTINFO_SURPLUS (62)
499 /* Number of additional slots in the dtv allocated. */
500 #define DTV_SURPLUS (14)
502 /* Initial dtv of the main thread, not allocated with normal malloc. */
503 EXTERN
void *_dl_initial_dtv
;
504 /* Generation counter for the dtv. */
505 EXTERN
size_t _dl_tls_generation
;
507 EXTERN
void (*_dl_init_static_tls
) (struct link_map
*);
509 EXTERN
void (*_dl_wait_lookup_done
) (void);
511 /* Scopes to free after next THREAD_GSCOPE_WAIT (). */
512 EXTERN
struct dl_scope_free_list
516 } *_dl_scope_free_list
;
519 # define __rtld_global_attribute__
521 # ifdef HAVE_SDATA_SECTION
522 # define __rtld_local_attribute__ \
523 __attribute__ ((visibility ("hidden"), section (".sdata")))
524 # undef __rtld_global_attribute__
525 # define __rtld_global_attribute__ __attribute__ ((section (".sdata")))
527 # define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
529 extern struct rtld_global _rtld_local __rtld_local_attribute__
;
530 # undef __rtld_local_attribute__
532 extern struct rtld_global _rtld_global __rtld_global_attribute__
;
533 # undef __rtld_global_attribute__
537 # define GLRO(name) _##name
540 # define GLRO(name) _rtld_local_ro._##name
542 # define GLRO(name) _rtld_global_ro._##name
544 struct rtld_global_ro
548 /* If nonzero the appropriate debug information is printed. */
549 EXTERN
int _dl_debug_mask
;
550 #define DL_DEBUG_LIBS (1 << 0)
551 #define DL_DEBUG_IMPCALLS (1 << 1)
552 #define DL_DEBUG_BINDINGS (1 << 2)
553 #define DL_DEBUG_SYMBOLS (1 << 3)
554 #define DL_DEBUG_VERSIONS (1 << 4)
555 #define DL_DEBUG_RELOC (1 << 5)
556 #define DL_DEBUG_FILES (1 << 6)
557 #define DL_DEBUG_STATISTICS (1 << 7)
558 #define DL_DEBUG_UNUSED (1 << 8)
559 #define DL_DEBUG_SCOPES (1 << 9)
560 /* These two are used only internally. */
561 #define DL_DEBUG_HELP (1 << 10)
562 #define DL_DEBUG_PRELINK (1 << 11)
565 EXTERN
unsigned int _dl_osversion
;
567 EXTERN
const char *_dl_platform
;
568 EXTERN
size_t _dl_platformlen
;
570 /* Cached value of `getpagesize ()'. */
571 EXTERN
size_t _dl_pagesize
;
573 /* Copy of the content of `_dl_main_searchlist' at startup time. */
574 EXTERN
struct r_scope_elem _dl_initial_searchlist
;
576 /* CLK_TCK as reported by the kernel. */
577 EXTERN
int _dl_clktck
;
579 /* If nonzero print warnings messages. */
580 EXTERN
int _dl_verbose
;
582 /* File descriptor to write debug messages to. */
583 EXTERN
int _dl_debug_fd
;
585 /* Do we do lazy relocations? */
588 /* Nonzero if runtime lookups should not update the .got/.plt. */
589 EXTERN
int _dl_bind_not
;
591 /* Nonzero if references should be treated as weak during runtime
593 EXTERN
int _dl_dynamic_weak
;
595 /* Default floating-point control word. */
596 EXTERN fpu_control_t _dl_fpu_control
;
598 /* Expected cache ID. */
599 EXTERN
int _dl_correct_cache_id
;
601 /* Mask for hardware capabilities that are available. */
602 EXTERN
uint64_t _dl_hwcap
;
604 /* Mask for important hardware capabilities we honour. */
605 EXTERN
uint64_t _dl_hwcap_mask
;
607 /* Get architecture specific definitions. */
608 #define PROCINFO_DECL
609 #ifndef PROCINFO_CLASS
610 # define PROCINFO_CLASS EXTERN
612 #include <dl-procinfo.c>
614 /* Names of shared object for which the RPATH should be ignored. */
615 EXTERN
const char *_dl_inhibit_rpath
;
617 /* Location of the binary. */
618 EXTERN
const char *_dl_origin_path
;
620 /* -1 if the dynamic linker should honor library load bias,
621 0 if not, -2 use the default (honor biases for normal
622 binaries, don't honor for PIEs). */
623 EXTERN
ElfW(Addr
) _dl_use_load_bias
;
625 /* Name of the shared object to be profiled (if any). */
626 EXTERN
const char *_dl_profile
;
627 /* Filename of the output file. */
628 EXTERN
const char *_dl_profile_output
;
629 /* Name of the object we want to trace the prelinking. */
630 EXTERN
const char *_dl_trace_prelink
;
631 /* Map of shared object to be prelink traced. */
632 EXTERN
struct link_map
*_dl_trace_prelink_map
;
634 /* All search directories defined at startup. */
635 EXTERN
struct r_search_path_elem
*_dl_init_all_dirs
;
637 #if HP_TIMING_AVAIL || HP_SMALL_TIMING_AVAIL
638 /* Overhead of a high-precision timing measurement. */
639 EXTERN hp_timing_t _dl_hp_timing_overhead
;
642 #ifdef NEED_DL_SYSINFO
643 /* Syscall handling improvements. This is very specific to x86. */
644 EXTERN
uintptr_t _dl_sysinfo
;
647 #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
648 /* The vsyscall page is a virtual DSO pre-mapped by the kernel.
649 This points to its ELF header. */
650 EXTERN
const ElfW(Ehdr
) *_dl_sysinfo_dso
;
652 /* At startup time we set up the normal DSO data structure for it,
653 and this points to it. */
654 EXTERN
struct link_map
*_dl_sysinfo_map
;
658 /* We add a function table to _rtld_global which is then used to
659 call the function instead of going through the PLT. The result
660 is that we can avoid exporting the functions and we do not jump
661 PLT relocations in libc.so. */
662 void (*_dl_debug_printf
) (const char *, ...)
663 __attribute__ ((__format__ (__printf__
, 1, 2)));
664 int (internal_function
*_dl_catch_error
) (const char **, const char **,
665 bool *, void (*) (void *), void *);
666 void (internal_function
*_dl_signal_error
) (int, const char *, const char *,
668 void (*_dl_mcount
) (ElfW(Addr
) frompc
, ElfW(Addr
) selfpc
);
669 lookup_t (internal_function
*_dl_lookup_symbol_x
) (const char *,
672 struct r_scope_elem
*[],
673 const struct r_found_version
*,
676 int (*_dl_check_caller
) (const void *, enum allowmask
);
677 void *(*_dl_open
) (const char *file
, int mode
, const void *caller_dlopen
,
678 Lmid_t nsid
, int argc
, char *argv
[], char *env
[]);
679 void (*_dl_close
) (void *map
);
680 void *(*_dl_tls_get_addr_soft
) (struct link_map
*);
681 #ifdef HAVE_DL_DISCOVER_OSVERSION
682 int (*_dl_discover_osversion
) (void);
685 /* List of auditing interfaces. */
686 struct audit_ifaces
*_dl_audit
;
687 unsigned int _dl_naudit
;
689 /* 0 if internal pointer values should not be guarded, 1 if they should. */
690 EXTERN
int _dl_pointer_guard
;
692 # define __rtld_global_attribute__
694 # define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
695 extern struct rtld_global_ro _rtld_local_ro
696 attribute_relro __rtld_local_attribute__
;
697 extern struct rtld_global_ro _rtld_global_ro
698 attribute_relro __rtld_global_attribute__
;
699 # undef __rtld_local_attribute__
701 /* We cheat a bit here. We declare the variable as as const even
702 though it is at startup. */
703 extern const struct rtld_global_ro _rtld_global_ro
704 attribute_relro __rtld_global_attribute__
;
706 # undef __rtld_global_attribute__
711 /* This is the initial value of GL(dl_error_catch_tsd).
712 A non-TLS libpthread will change it. */
713 extern void **_dl_initial_error_catch_tsd (void) __attribute__ ((const))
717 /* This is the initial value of GL(dl_make_stack_executable_hook).
718 A threads library can change it. */
719 extern int _dl_make_stack_executable (void **stack_endp
) internal_function
;
720 rtld_hidden_proto (_dl_make_stack_executable
)
722 /* Variable pointing to the end of the stack (or close to it). This value
723 must be constant over the runtime of the application. Some programs
724 might use the variable which results in copy relocations on some
725 platforms. But this does not matter, ld.so can always use the local
727 extern void *__libc_stack_end attribute_relro
;
728 rtld_hidden_proto (__libc_stack_end
)
730 /* Parameters passed to the dynamic linker. */
731 extern int _dl_argc attribute_hidden attribute_relro
;
732 extern char **_dl_argv
733 #ifndef DL_ARGV_NOT_RELRO
738 extern char **_dl_argv_internal attribute_hidden
739 # ifndef DL_ARGV_NOT_RELRO
743 # define rtld_progname (INTUSE(_dl_argv)[0])
745 # define rtld_progname _dl_argv[0]
748 /* Flag set at startup and cleared when the last initializer has run. */
749 extern int _dl_starting_up
;
750 weak_extern (_dl_starting_up
)
752 extern int _dl_starting_up_internal attribute_hidden
;
755 /* Random data provided by the kernel. */
756 extern void *_dl_random attribute_hidden attribute_relro
;
758 /* OS-dependent function to open the zero-fill device. */
759 extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */
762 /* Write message on the debug file descriptor. The parameters are
763 interpreted as for a `printf' call. All the lines start with a
764 tag showing the PID. */
765 extern void _dl_debug_printf (const char *fmt
, ...)
766 __attribute__ ((__format__ (__printf__
, 1, 2))) attribute_hidden
;
768 /* Write message on the debug file descriptor. The parameters are
769 interpreted as for a `printf' call. All the lines buf the first
770 start with a tag showing the PID. */
771 extern void _dl_debug_printf_c (const char *fmt
, ...)
772 __attribute__ ((__format__ (__printf__
, 1, 2)));
775 /* Write a message on the specified descriptor FD. The parameters are
776 interpreted as for a `printf' call. */
777 extern void _dl_dprintf (int fd
, const char *fmt
, ...)
778 __attribute__ ((__format__ (__printf__
, 2, 3)))
781 /* Write a message on the specified descriptor standard output. The
782 parameters are interpreted as for a `printf' call. */
783 #define _dl_printf(fmt, args...) \
784 _dl_dprintf (STDOUT_FILENO, fmt, ##args)
786 /* Write a message on the specified descriptor standard error. The
787 parameters are interpreted as for a `printf' call. */
788 #define _dl_error_printf(fmt, args...) \
789 _dl_dprintf (STDERR_FILENO, fmt, ##args)
791 /* Write a message on the specified descriptor standard error and exit
792 the program. The parameters are interpreted as for a `printf' call. */
793 #define _dl_fatal_printf(fmt, args...) \
796 _dl_dprintf (STDERR_FILENO, fmt, ##args); \
802 /* This function is called by all the internal dynamic linker functions
803 when they encounter an error. ERRCODE is either an `errno' code or
804 zero; OBJECT is the name of the problematical shared object, or null if
805 it is a general problem; ERRSTRING is a string describing the specific
807 extern void _dl_signal_error (int errcode
, const char *object
,
808 const char *occurred
, const char *errstring
)
809 internal_function
__attribute__ ((__noreturn__
)) attribute_hidden
;
811 /* Like _dl_signal_error, but may return when called in the context of
812 _dl_receive_error. */
813 extern void _dl_signal_cerror (int errcode
, const char *object
,
814 const char *occation
, const char *errstring
)
817 /* Call OPERATE, receiving errors from `dl_signal_cerror'. Unlike
818 `_dl_catch_error' the operation is resumed after the OPERATE
820 ARGS is passed as argument to OPERATE. */
821 extern void _dl_receive_error (receiver_fct fct
, void (*operate
) (void *),
826 /* Open the shared object NAME and map in its segments.
827 LOADER's DT_RPATH is used in searching for NAME.
828 If the object is already opened, returns its existing map. */
829 extern struct link_map
*_dl_map_object (struct link_map
*loader
,
831 int type
, int trace_mode
, int mode
,
833 internal_function attribute_hidden
;
835 /* Call _dl_map_object on the dependencies of MAP, and set up
836 MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously
837 loaded objects that will be inserted into MAP->l_searchlist after MAP
838 but before its dependencies. */
839 extern void _dl_map_object_deps (struct link_map
*map
,
840 struct link_map
**preloads
,
841 unsigned int npreloads
, int trace_mode
,
843 internal_function attribute_hidden
;
845 /* Cache the locations of MAP's hash table. */
846 extern void _dl_setup_hash (struct link_map
*map
)
847 internal_function attribute_hidden
;
850 /* Collect the directories in the search path for LOADER's dependencies.
851 The data structure is defined in <dlfcn.h>. If COUNTING is true,
852 SI->dls_cnt and SI->dls_size are set; if false, those must be as set
853 by a previous call with COUNTING set, and SI must point to SI->dls_size
854 bytes to be used in filling in the result. */
855 extern void _dl_rtld_di_serinfo (struct link_map
*loader
,
856 Dl_serinfo
*si
, bool counting
)
860 /* Search loaded objects' symbol tables for a definition of the symbol
861 referred to by UNDEF. *SYM is the symbol table entry containing the
862 reference; it is replaced with the defining symbol, and the base load
863 address of the defining object is returned. SYMBOL_SCOPE is a
864 null-terminated list of object scopes to search; each object's
865 l_searchlist (i.e. the segment of the dependency tree starting at that
866 object) is searched in turn. REFERENCE_NAME should name the object
867 containing the reference; it is used in error messages.
868 TYPE_CLASS describes the type of symbol we are looking for. */
871 /* If necessary add dependency between user and provider object. */
872 DL_LOOKUP_ADD_DEPENDENCY
= 1,
873 /* Return most recent version instead of default version for
874 unversioned lookup. */
875 DL_LOOKUP_RETURN_NEWEST
= 2,
876 /* Set if dl_lookup* called with GSCOPE lock held. */
877 DL_LOOKUP_GSCOPE_LOCK
= 4,
880 /* Lookup versioned symbol. */
881 extern lookup_t
_dl_lookup_symbol_x (const char *undef
,
882 struct link_map
*undef_map
,
883 const ElfW(Sym
) **sym
,
884 struct r_scope_elem
*symbol_scope
[],
885 const struct r_found_version
*version
,
886 int type_class
, int flags
,
887 struct link_map
*skip_map
)
888 internal_function attribute_hidden
;
891 /* Look up symbol NAME in MAP's scope and return its run-time address. */
892 extern ElfW(Addr
) _dl_symbol_value (struct link_map
*map
, const char *name
)
895 /* Add the new link_map NEW to the end of the namespace list. */
896 extern void _dl_add_to_namespace_list (struct link_map
*new, Lmid_t nsid
)
897 internal_function attribute_hidden
;
899 /* Allocate a `struct link_map' for a new object being loaded. */
900 extern struct link_map
*_dl_new_object (char *realname
, const char *libname
,
901 int type
, struct link_map
*loader
,
902 int mode
, Lmid_t nsid
)
903 internal_function attribute_hidden
;
905 /* Relocate the given object (if it hasn't already been).
906 SCOPE is passed to _dl_lookup_symbol in symbol lookups.
907 If RTLD_LAZY is set in RELOC-MODE, don't relocate its PLT. */
908 extern void _dl_relocate_object (struct link_map
*map
,
909 struct r_scope_elem
*scope
[],
910 int reloc_mode
, int consider_profiling
)
913 /* Protect PT_GNU_RELRO area. */
914 extern void _dl_protect_relro (struct link_map
*map
)
915 internal_function attribute_hidden
;
917 /* Call _dl_signal_error with a message about an unhandled reloc type.
918 TYPE is the result of ELFW(R_TYPE) (r_info), i.e. an R_<CPU>_* value.
919 PLT is nonzero if this was a PLT reloc; it just affects the message. */
920 extern void _dl_reloc_bad_type (struct link_map
*map
,
921 unsigned int type
, int plt
)
922 internal_function
__attribute__ ((__noreturn__
));
924 /* Resolve conflicts if prelinking. */
925 extern void _dl_resolve_conflicts (struct link_map
*l
,
926 ElfW(Rela
) *conflict
,
927 ElfW(Rela
) *conflictend
);
929 /* Check the version dependencies of all objects available through
930 MAP. If VERBOSE print some more diagnostics. */
931 extern int _dl_check_all_versions (struct link_map
*map
, int verbose
,
935 /* Check the version dependencies for MAP. If VERBOSE print some more
937 extern int _dl_check_map_versions (struct link_map
*map
, int verbose
,
941 /* Initialize the object in SCOPE by calling the constructors with
942 ARGC, ARGV, and ENV as the parameters. */
943 extern void _dl_init (struct link_map
*main_map
, int argc
, char **argv
,
944 char **env
) internal_function attribute_hidden
;
946 /* Call the finalizer functions of all shared objects whose
947 initializer functions have completed. */
948 extern void _dl_fini (void) internal_function
;
950 /* Sort array MAPS according to dependencies of the contained objects. */
951 extern void _dl_sort_fini (struct link_map
**maps
, size_t nmaps
, char *used
,
955 /* The dynamic linker calls this function before and having changing
956 any shared object mappings. The `r_state' member of `struct r_debug'
957 says what change is taking place. This function's address is
958 the value of the `r_brk' member. */
959 extern void _dl_debug_state (void);
960 rtld_hidden_proto (_dl_debug_state
)
962 /* Initialize `struct r_debug' if it has not already been done. The
963 argument is the run-time load address of the dynamic linker, to be put
964 in the `r_ldbase' member. Returns the address of the structure. */
965 extern struct r_debug
*_dl_debug_initialize (ElfW(Addr
) ldbase
, Lmid_t ns
)
968 /* Initialize the basic data structure for the search paths. */
969 extern void _dl_init_paths (const char *library_path
) internal_function
;
971 /* Gather the information needed to install the profiling tables and start
973 extern void _dl_start_profile (void) internal_function attribute_hidden
;
975 /* The actual functions used to keep book on the calls. */
976 extern void _dl_mcount (ElfW(Addr
) frompc
, ElfW(Addr
) selfpc
);
977 extern void _dl_mcount_internal (ElfW(Addr
) frompc
, ElfW(Addr
) selfpc
)
980 /* This function is simply a wrapper around the _dl_mcount function
981 which does not require a FROMPC parameter since this is the
983 extern void _dl_mcount_wrapper (void *selfpc
);
985 /* Show the members of the auxiliary array passed up from the kernel. */
986 extern void _dl_show_auxv (void) internal_function
;
988 /* Return all environment variables starting with `LD_', one after the
990 extern char *_dl_next_ld_env_entry (char ***position
) internal_function
;
992 /* Return an array with the names of the important hardware capabilities. */
993 extern const struct r_strlenpair
*_dl_important_hwcaps (const char *platform
,
996 size_t *max_capstrlen
)
999 /* Look up NAME in ld.so.cache and return the file name stored there,
1000 or null if none is found. */
1001 extern const char *_dl_load_cache_lookup (const char *name
)
1004 /* If the system does not support MAP_COPY we cannot leave the file open
1005 all the time since this would create problems when the file is replaced.
1006 Therefore we provide this function to close the file and open it again
1008 extern void _dl_unload_cache (void) attribute_hidden
;
1010 /* System-dependent function to read a file's whole contents in the
1011 most convenient manner available. *SIZEP gets the size of the
1012 file. On error MAP_FAILED is returned. */
1013 extern void *_dl_sysdep_read_whole_file (const char *file
, size_t *sizep
,
1015 internal_function attribute_hidden
;
1017 /* System-specific function to do initial startup for the dynamic linker.
1018 After this, file access calls and getenv must work. This is responsible
1019 for setting __libc_enable_secure if we need to be secure (e.g. setuid),
1020 and for setting _dl_argc and _dl_argv, and then calling _dl_main. */
1021 extern ElfW(Addr
) _dl_sysdep_start (void **start_argptr
,
1022 void (*dl_main
) (const ElfW(Phdr
) *phdr
,
1024 ElfW(Addr
) *user_entry
,
1025 ElfW(auxv_t
) *auxv
))
1028 extern void _dl_sysdep_start_cleanup (void)
1029 internal_function attribute_hidden
;
1032 /* Determine next available module ID. */
1033 extern size_t _dl_next_tls_modid (void) internal_function attribute_hidden
;
1035 /* Calculate offset of the TLS blocks in the static TLS block. */
1036 extern void _dl_determine_tlsoffset (void) internal_function attribute_hidden
;
1038 /* Set up the data structures for TLS, when they were not set up at startup.
1039 Returns nonzero on malloc failure.
1040 This is called from _dl_map_object_from_fd or by libpthread. */
1041 extern int _dl_tls_setup (void) internal_function
;
1042 rtld_hidden_proto (_dl_tls_setup
)
1044 /* Allocate memory for static TLS block (unless MEM is nonzero) and dtv. */
1045 extern void *_dl_allocate_tls (void *mem
) internal_function
;
1046 rtld_hidden_proto (_dl_allocate_tls
)
1048 /* Get size and alignment requirements of the static TLS block. */
1049 extern void _dl_get_tls_static_info (size_t *sizep
, size_t *alignp
)
1052 extern void _dl_allocate_static_tls (struct link_map
*map
)
1053 internal_function attribute_hidden
;
1055 /* These are internal entry points to the two halves of _dl_allocate_tls,
1056 only used within rtld.c itself at startup time. */
1057 extern void *_dl_allocate_tls_storage (void)
1058 internal_function attribute_hidden
;
1059 extern void *_dl_allocate_tls_init (void *) internal_function
;
1060 rtld_hidden_proto (_dl_allocate_tls_init
)
1062 /* Deallocate memory allocated with _dl_allocate_tls. */
1063 extern void _dl_deallocate_tls (void *tcb
, bool dealloc_tcb
) internal_function
;
1064 rtld_hidden_proto (_dl_deallocate_tls
)
1066 extern void _dl_nothread_init_static_tls (struct link_map
*) attribute_hidden
;
1068 /* Find origin of the executable. */
1069 extern const char *_dl_get_origin (void) attribute_hidden
;
1072 extern size_t _dl_dst_count (const char *name
, int is_path
) attribute_hidden
;
1074 /* Substitute DST values. */
1075 extern char *_dl_dst_substitute (struct link_map
*l
, const char *name
,
1076 char *result
, int is_path
) attribute_hidden
;
1078 /* Check validity of the caller. */
1079 extern int _dl_check_caller (const void *caller
, enum allowmask mask
)
1082 /* Open the shared object NAME, relocate it, and run its initializer if it
1083 hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If
1084 the object is already opened, returns its existing map. */
1085 extern void *_dl_open (const char *name
, int mode
, const void *caller
,
1086 Lmid_t nsid
, int argc
, char *argv
[], char *env
[])
1089 /* Free or queue for freeing scope OLD. If other threads might be
1090 in the middle of _dl_fixup, _dl_profile_fixup or dl*sym using the
1091 old scope, OLD can't be freed until no thread is using it. */
1092 extern int _dl_scope_free (void *) attribute_hidden
;
1094 /* Add module to slot information data. */
1095 extern void _dl_add_to_slotinfo (struct link_map
*l
) attribute_hidden
;
1097 /* Update slot information data for at least the generation of the
1098 module with the given index. */
1099 extern struct link_map
*_dl_update_slotinfo (unsigned long int req_modid
);
1101 /* Look up the module's TLS block as for __tls_get_addr,
1102 but never touch anything. Return null if it's not allocated yet. */
1103 extern void *_dl_tls_get_addr_soft (struct link_map
*l
) attribute_hidden
;
1105 extern int _dl_addr_inside_object (struct link_map
*l
, const ElfW(Addr
) addr
)
1106 internal_function attribute_hidden
;
1108 /* Show show of an object. */
1109 extern void _dl_show_scope (struct link_map
*new, int from
);
1113 #endif /* ldsodefs.h */