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 #ifndef TLS_STATIC_EXTRA_SURPLUS
61 # define TLS_STATIC_EXTRA_SURPLUS 0
64 /* Result of the lookup functions and how to retrieve the base address. */
65 typedef struct link_map *lookup_t;
66 #define LOOKUP_VALUE(map) map
67 #define LOOKUP_VALUE_ADDRESS(map) ((map) ? (map)->l_addr : 0)
69 /* On some architectures a pointer to a function is not just a pointer
70 to the actual code of the function but rather an architecture
71 specific descriptor. */
72 #ifndef ELF_FUNCTION_PTR_IS_SPECIAL
73 # define DL_SYMBOL_ADDRESS(map, ref) \
74 (void *) (LOOKUP_VALUE_ADDRESS (map) + ref->st_value)
75 # define DL_LOOKUP_ADDRESS(addr) ((ElfW(Addr)) (addr))
76 # define DL_DT_INIT_ADDRESS(map, start) (start)
77 # define DL_DT_FINI_ADDRESS(map, start) (start)
80 /* On some architectures dladdr can't use st_size of all symbols this way. */
81 #define DL_ADDR_SYM_MATCH(L, SYM, MATCHSYM, ADDR) \
82 ((ADDR) >= (L)->l_addr + (SYM)->st_value \
83 && ((((SYM)->st_shndx == SHN_UNDEF || (SYM)->st_size == 0) \
84 && (ADDR) == (L)->l_addr + (SYM)->st_value) \
85 || (ADDR) < (L)->l_addr + (SYM)->st_value + (SYM)->st_size) \
86 && ((MATCHSYM) == NULL || (MATCHSYM)->st_value < (SYM)->st_value))
88 /* Unmap a loaded object, called by _dl_close (). */
89 #ifndef DL_UNMAP_IS_SPECIAL
90 # define DL_UNMAP(map) \
91 __munmap ((void *) (map)->l_map_start, \
92 (map)->l_map_end - (map)->l_map_start)
95 /* By default we do not need special support to initialize DSOs loaded
96 by statically linked binaries. */
97 #ifndef DL_STATIC_INIT
98 # define DL_STATIC_INIT(map)
101 /* Reloc type classes as returned by elf_machine_type_class().
102 ELF_RTYPE_CLASS_PLT means this reloc should not be satisfied by
103 some PLT symbol, ELF_RTYPE_CLASS_COPY means this reloc should not be
104 satisfied by any symbol in the executable. Some architectures do
105 not support copy relocations. In this case we define the macro to
106 zero so that the code for handling them gets automatically optimized
108 #define ELF_RTYPE_CLASS_PLT 1
109 #ifndef DL_NO_COPY_RELOCS
110 # define ELF_RTYPE_CLASS_COPY 2
112 # define ELF_RTYPE_CLASS_COPY 0
115 /* ELF uses the PF_x macros to specify the segment permissions, mmap
116 uses PROT_xxx. In most cases the three macros have the values 1, 2,
117 and 3 but not in a matching order. The following macros allows
118 converting from the PF_x values to PROT_xxx values. */
120 ((PROT_READ << (PF_R * 4)) \
121 | (PROT_WRITE << (PF_W * 4)) \
122 | (PROT_EXEC << (PF_X * 4)) \
123 | ((PROT_READ | PROT_WRITE) << ((PF_R | PF_W) * 4)) \
124 | ((PROT_READ | PROT_EXEC) << ((PF_R | PF_X) * 4)) \
125 | ((PROT_WRITE | PROT_EXEC) << (PF_W | PF_X) * 4) \
126 | ((PROT_READ | PROT_WRITE | PROT_EXEC) << ((PF_R | PF_W | PF_X) * 4)))
129 /* For the version handling we need an array with only names and their
131 struct r_found_version
137 const char *filename;
140 /* We want to cache information about the searches for shared objects. */
142 enum r_dir_status { unknown, nonexisting, existing };
144 struct r_search_path_elem
146 /* This link is only used in the `all_dirs' member of `r_search_path'. */
147 struct r_search_path_elem *next;
149 /* Strings saying where the definition came from. */
153 /* Basename for this search path element. The string must end with
154 a slash character. */
158 enum r_dir_status status[0];
168 /* A data structure for a simple single linked list of strings. */
171 const char *name; /* Name requested (before search). */
172 struct libname_list *next; /* Link to next name for this object. */
173 int dont_free; /* Flag whether this element should be freed
174 if the object is not entirely unloaded. */
178 /* Bit masks for the objects which valid callers can come from to
179 functions with restricted interface. */
184 allow_libpthread = 4,
189 /* Type for list of auditing interfaces. */
191 struct La_i86_retval;
192 struct La_x86_64_regs;
193 struct La_x86_64_retval;
194 struct La_ppc32_regs;
195 struct La_ppc32_retval;
196 struct La_ppc64_regs;
197 struct La_ppc64_retval;
200 struct La_alpha_regs;
201 struct La_alpha_retval;
202 struct La_s390_32_regs;
203 struct La_s390_32_retval;
204 struct La_s390_64_regs;
205 struct La_s390_64_retval;
207 struct La_ia64_retval;
208 struct La_sparc32_regs;
209 struct La_sparc32_retval;
210 struct La_sparc64_regs;
211 struct La_sparc64_retval;
215 void (*activity) (uintptr_t *, unsigned int);
216 char *(*objsearch) (const char *, uintptr_t *, unsigned int);
217 unsigned int (*objopen) (struct link_map *, Lmid_t, uintptr_t *);
218 void (*preinit) (uintptr_t *);
221 uintptr_t (*symbind32) (Elf32_Sym *, unsigned int, uintptr_t *,
222 uintptr_t *, unsigned int *, const char *);
223 uintptr_t (*symbind64) (Elf64_Sym *, unsigned int, uintptr_t *,
224 uintptr_t *, unsigned int *, const char *);
228 Elf32_Addr (*i86_gnu_pltenter) (Elf32_Sym *, unsigned int, uintptr_t *,
229 uintptr_t *, struct La_i86_regs *,
230 unsigned int *, const char *name,
231 long int *framesizep);
232 Elf64_Addr (*x86_64_gnu_pltenter) (Elf64_Sym *, unsigned int, uintptr_t *,
233 uintptr_t *, struct La_x86_64_regs *,
234 unsigned int *, const char *name,
235 long int *framesizep);
236 Elf32_Addr (*ppc32_gnu_pltenter) (Elf32_Sym *, unsigned int, uintptr_t *,
237 uintptr_t *, struct La_ppc32_regs *,
238 unsigned int *, const char *name,
239 long int *framesizep);
240 Elf64_Addr (*ppc64_gnu_pltenter) (Elf64_Sym *, unsigned int, uintptr_t *,
241 uintptr_t *, struct La_ppc64_regs *,
242 unsigned int *, const char *name,
243 long int *framesizep);
244 uintptr_t (*sh_gnu_pltenter) (Elf32_Sym *, unsigned int, uintptr_t *,
245 uintptr_t *, const struct La_sh_regs *,
246 unsigned int *, const char *name,
247 long int *framesizep);
248 Elf64_Addr (*alpha_gnu_pltenter) (Elf64_Sym *, unsigned int, uintptr_t *,
249 uintptr_t *, struct La_alpha_regs *,
250 unsigned int *, const char *name,
251 long int *framesizep);
252 Elf32_Addr (*s390_32_gnu_pltenter) (Elf32_Sym *, unsigned int, uintptr_t *,
253 uintptr_t *, struct La_s390_32_regs *,
254 unsigned int *, const char *name,
255 long int *framesizep);
256 Elf64_Addr (*s390_64_gnu_pltenter) (Elf64_Sym *, unsigned int, uintptr_t *,
257 uintptr_t *, struct La_s390_64_regs *,
258 unsigned int *, const char *name,
259 long int *framesizep);
260 Elf64_Addr (*ia64_gnu_pltenter) (Elf64_Sym *, unsigned int, uintptr_t *,
261 uintptr_t *, struct La_ia64_regs *,
262 unsigned int *, const char *name,
263 long int *framesizep);
264 Elf32_Addr (*sparc32_gnu_pltenter) (Elf32_Sym *, unsigned int,
265 uintptr_t *, uintptr_t *,
266 const struct La_sparc32_regs *,
267 unsigned int *, const char *name,
268 long int *framesizep);
269 Elf64_Addr (*sparc64_gnu_pltenter) (Elf64_Sym *, unsigned int,
270 uintptr_t *, uintptr_t *,
271 const struct La_sparc64_regs *,
272 unsigned int *, const char *name,
273 long int *framesizep);
274 #ifdef ARCH_PLTENTER_MEMBERS
275 ARCH_PLTENTER_MEMBERS;
280 unsigned int (*i86_gnu_pltexit) (Elf32_Sym *, unsigned int, uintptr_t *,
281 uintptr_t *, const struct La_i86_regs *,
282 struct La_i86_retval *, const char *);
283 unsigned int (*x86_64_gnu_pltexit) (Elf64_Sym *, unsigned int, uintptr_t *,
285 const struct La_x86_64_regs *,
286 struct La_x86_64_retval *,
288 unsigned int (*ppc32_gnu_pltexit) (Elf32_Sym *, unsigned int, uintptr_t *,
290 const struct La_ppc32_regs *,
291 struct La_ppc32_retval *, const char *);
292 unsigned int (*ppc64_gnu_pltexit) (Elf64_Sym *, unsigned int, uintptr_t *,
294 const struct La_ppc64_regs *,
295 struct La_ppc64_retval *, const char *);
296 unsigned int (*sh_gnu_pltexit) (Elf32_Sym *, unsigned int, uintptr_t *,
297 uintptr_t *, const struct La_sh_regs *,
298 struct La_sh_retval *, const char *);
299 unsigned int (*alpha_gnu_pltexit) (Elf64_Sym *, unsigned int, uintptr_t *,
301 const struct La_alpha_regs *,
302 struct La_alpha_retval *, const char *);
303 unsigned int (*s390_32_gnu_pltexit) (Elf32_Sym *, unsigned int,
304 uintptr_t *, uintptr_t *,
305 const struct La_s390_32_regs *,
306 struct La_s390_32_retval *,
308 unsigned int (*s390_64_gnu_pltexit) (Elf64_Sym *, unsigned int,
309 uintptr_t *, uintptr_t *,
310 const struct La_s390_64_regs *,
311 struct La_s390_64_retval *,
313 unsigned int (*ia64_gnu_pltexit) (Elf64_Sym *, unsigned int, uintptr_t *,
315 const struct La_ia64_regs *,
316 struct La_ia64_retval *, const char *);
317 unsigned int (*sparc32_gnu_pltexit) (Elf32_Sym *, unsigned int,
318 uintptr_t *, uintptr_t *,
319 const struct La_sparc32_regs *,
320 struct La_sparc32_retval *,
322 unsigned int (*sparc64_gnu_pltexit) (Elf64_Sym *, unsigned int,
323 uintptr_t *, uintptr_t *,
324 const struct La_sparc32_regs *,
325 struct La_sparc32_retval *,
327 #ifdef ARCH_PLTEXIT_MEMBERS
328 ARCH_PLTEXIT_MEMBERS;
331 unsigned int (*objclose) (uintptr_t *);
333 struct audit_ifaces *next;
337 /* Test whether given NAME matches any of the names of the given object. */
338 extern int _dl_name_match_p (const char *__name, const struct link_map *__map)
341 /* Function used as argument for `_dl_receive_error' function. The
342 arguments are the error code, error string, and the objname the
343 error occurred in. */
344 typedef void (*receiver_fct) (int, const char *, const char *);
346 /* Internal functions of the run-time dynamic linker.
347 These can be accessed if you link again the dynamic linker
348 as a shared library, as in `-lld' or `/lib/ld.so' explicitly;
349 but are not normally of interest to user programs.
351 The `-ldl' library functions in <dlfcn.h> provide a simple
352 user interface to run-time dynamic linking. */
356 # define EXTERN extern
357 # define GL(name) _##name
361 # define GL(name) _rtld_local._##name
363 # define GL(name) _rtld_global._##name
368 /* Don't change the order of the following elements. 'dl_loaded'
369 must remain the first element. Forever. */
371 /* Non-shared code has no support for multiple namespaces. */
377 EXTERN struct link_namespaces
379 /* A pointer to the map for the main map. */
380 struct link_map *_ns_loaded;
381 /* Number of object in the _dl_loaded list. */
382 unsigned int _ns_nloaded;
383 /* Direct pointer to the searchlist of the main object. */
384 struct r_scope_elem *_ns_main_searchlist;
385 /* This is zero at program start to signal that the global scope map is
386 allocated by rtld. Later it keeps the size of the map. It might be
387 reset if in _dl_close if the last global object is removed. */
388 size_t _ns_global_scope_alloc;
389 /* Keep track of changes to each namespace' list. */
390 struct r_debug _ns_debug;
393 /* During the program run we must not modify the global data of
394 loaded shared object simultanously in two threads. Therefore we
395 protect `_dl_open' and `_dl_close' in dl-close.c.
397 This must be a recursive lock since the initializer function of
398 the loaded object might as well require a call to this function.
399 At this time it is not anymore a problem to modify the tables. */
400 __rtld_lock_define_recursive (EXTERN, _dl_load_lock)
402 /* Incremented whenever something may have been added to dl_loaded. */
403 EXTERN unsigned long long _dl_load_adds;
406 /* File descriptor referring to the zero-fill device. */
407 EXTERN int _dl_zerofd;
410 /* The object to be initialized first. */
411 EXTERN struct link_map *_dl_initfirst;
413 #if HP_TIMING_AVAIL || HP_SMALL_TIMING_AVAIL
414 /* Start time on CPU clock. */
415 EXTERN hp_timing_t _dl_cpuclock_offset;
418 /* Map of shared object to be profiled. */
419 EXTERN struct link_map *_dl_profile_map;
421 /* Counters for the number of relocations performed. */
422 EXTERN unsigned long int _dl_num_relocations;
423 EXTERN unsigned long int _dl_num_cache_relocations;
425 /* List of search directories. */
426 EXTERN struct r_search_path_elem *_dl_all_dirs;
428 #ifdef _LIBC_REENTRANT
429 EXTERN void **(*_dl_error_catch_tsd) (void) __attribute__ ((const));
432 /* Structure describing the dynamic linker itself. We need to
433 reserve memory for the data the audit libraries need. */
434 EXTERN struct link_map _dl_rtld_map;
436 struct auditstate audit_data[DL_NNS];
439 #if defined SHARED && defined _LIBC_REENTRANT \
440 && defined __rtld_lock_default_lock_recursive
441 EXTERN void (*_dl_rtld_lock_recursive) (void *);
442 EXTERN void (*_dl_rtld_unlock_recursive) (void *);
445 /* If loading a shared object requires that we make the stack executable
446 when it was not, we do it by calling this function.
447 It returns an errno code or zero on success. */
448 EXTERN int (*_dl_make_stack_executable_hook) (void **) internal_function;
450 /* Prevailing state of the stack, PF_X indicating it's executable. */
451 EXTERN ElfW(Word) _dl_stack_flags;
453 /* Flag signalling whether there are gaps in the module ID allocation. */
454 EXTERN bool _dl_tls_dtv_gaps;
455 /* Highest dtv index currently needed. */
456 EXTERN size_t _dl_tls_max_dtv_idx;
457 /* Information about the dtv slots. */
458 EXTERN struct dtv_slotinfo_list
461 struct dtv_slotinfo_list *next;
465 struct link_map *map;
467 } *_dl_tls_dtv_slotinfo_list;
468 /* Number of modules in the static TLS block. */
469 EXTERN size_t _dl_tls_static_nelem;
470 /* Size of the static TLS block. */
471 EXTERN size_t _dl_tls_static_size;
472 /* Size actually allocated in the static TLS block. */
473 EXTERN size_t _dl_tls_static_used;
474 /* Alignment requirement of the static TLS block. */
475 EXTERN size_t _dl_tls_static_align;
477 /* Number of additional entries in the slotinfo array of each slotinfo
478 list element. A large number makes it almost certain take we never
479 have to iterate beyond the first element in the slotinfo list. */
480 #define TLS_SLOTINFO_SURPLUS (62)
482 /* Number of additional slots in the dtv allocated. */
483 #define DTV_SURPLUS (14)
485 /* Initial dtv of the main thread, not allocated with normal malloc. */
486 EXTERN void *_dl_initial_dtv;
487 /* Generation counter for the dtv. */
488 EXTERN size_t _dl_tls_generation;
490 EXTERN void (*_dl_init_static_tls) (struct link_map *);
492 EXTERN void (*_dl_wait_lookup_done) (void);
494 /* Scopes to free after next THREAD_GSCOPE_WAIT (). */
495 EXTERN struct dl_scope_free_list
499 } *_dl_scope_free_list;
502 # define __rtld_global_attribute__
504 # ifdef HAVE_SDATA_SECTION
505 # define __rtld_local_attribute__ \
506 __attribute__ ((visibility ("hidden"), section (".sdata")))
507 # undef __rtld_global_attribute__
508 # define __rtld_global_attribute__ __attribute__ ((section (".sdata")))
510 # define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
512 extern struct rtld_global _rtld_local __rtld_local_attribute__;
513 # undef __rtld_local_attribute__
515 extern struct rtld_global _rtld_global __rtld_global_attribute__;
516 # undef __rtld_global_attribute__
520 # define GLRO(name) _##name
523 # define GLRO(name) _rtld_local_ro._##name
525 # define GLRO(name) _rtld_global_ro._##name
527 struct rtld_global_ro
531 /* If nonzero the appropriate debug information is printed. */
532 EXTERN int _dl_debug_mask;
533 #define DL_DEBUG_LIBS (1 << 0)
534 #define DL_DEBUG_IMPCALLS (1 << 1)
535 #define DL_DEBUG_BINDINGS (1 << 2)
536 #define DL_DEBUG_SYMBOLS (1 << 3)
537 #define DL_DEBUG_VERSIONS (1 << 4)
538 #define DL_DEBUG_RELOC (1 << 5)
539 #define DL_DEBUG_FILES (1 << 6)
540 #define DL_DEBUG_STATISTICS (1 << 7)
541 #define DL_DEBUG_UNUSED (1 << 8)
542 /* These two are used only internally. */
543 #define DL_DEBUG_HELP (1 << 9)
544 #define DL_DEBUG_PRELINK (1 << 10)
547 EXTERN unsigned int _dl_osversion;
549 EXTERN const char *_dl_platform;
550 EXTERN size_t _dl_platformlen;
552 /* Cached value of `getpagesize ()'. */
553 EXTERN size_t _dl_pagesize;
555 /* Copy of the content of `_dl_main_searchlist' at startup time. */
556 EXTERN struct r_scope_elem _dl_initial_searchlist;
558 /* CLK_TCK as reported by the kernel. */
559 EXTERN int _dl_clktck;
561 /* If nonzero print warnings messages. */
562 EXTERN int _dl_verbose;
564 /* File descriptor to write debug messages to. */
565 EXTERN int _dl_debug_fd;
567 /* Do we do lazy relocations? */
570 /* Nonzero if runtime lookups should not update the .got/.plt. */
571 EXTERN int _dl_bind_not;
573 /* Nonzero if references should be treated as weak during runtime
575 EXTERN int _dl_dynamic_weak;
577 /* Default floating-point control word. */
578 EXTERN fpu_control_t _dl_fpu_control;
580 /* Expected cache ID. */
581 EXTERN int _dl_correct_cache_id;
583 /* Mask for hardware capabilities that are available. */
584 EXTERN uint64_t _dl_hwcap;
586 /* Mask for important hardware capabilities we honour. */
587 EXTERN uint64_t _dl_hwcap_mask;
589 /* Get architecture specific definitions. */
590 #define PROCINFO_DECL
591 #ifndef PROCINFO_CLASS
592 # define PROCINFO_CLASS EXTERN
594 #include <dl-procinfo.c>
596 /* Platform-specific definitions. */
597 #ifdef PLATFORM_RTLD_GLOBAL_RO_FIELDS
598 PLATFORM_RTLD_GLOBAL_RO_FIELDS
601 /* Names of shared object for which the RPATH should be ignored. */
602 EXTERN const char *_dl_inhibit_rpath;
604 /* Location of the binary. */
605 EXTERN const char *_dl_origin_path;
607 /* -1 if the dynamic linker should honor library load bias,
608 0 if not, -2 use the default (honor biases for normal
609 binaries, don't honor for PIEs). */
610 EXTERN ElfW(Addr) _dl_use_load_bias;
612 /* Name of the shared object to be profiled (if any). */
613 EXTERN const char *_dl_profile;
614 /* Filename of the output file. */
615 EXTERN const char *_dl_profile_output;
616 /* Name of the object we want to trace the prelinking. */
617 EXTERN const char *_dl_trace_prelink;
618 /* Map of shared object to be prelink traced. */
619 EXTERN struct link_map *_dl_trace_prelink_map;
621 /* All search directories defined at startup. */
622 EXTERN struct r_search_path_elem *_dl_init_all_dirs;
624 #if HP_TIMING_AVAIL || HP_SMALL_TIMING_AVAIL
625 /* Overhead of a high-precision timing measurement. */
626 EXTERN hp_timing_t _dl_hp_timing_overhead;
629 #ifdef NEED_DL_SYSINFO
630 /* Syscall handling improvements. This is very specific to x86. */
631 EXTERN uintptr_t _dl_sysinfo;
634 #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
635 /* The vsyscall page is a virtual DSO pre-mapped by the kernel.
636 This points to its ELF header. */
637 EXTERN const ElfW(Ehdr) *_dl_sysinfo_dso;
639 /* At startup time we set up the normal DSO data structure for it,
640 and this points to it. */
641 EXTERN struct link_map *_dl_sysinfo_map;
645 /* We add a function table to _rtld_global which is then used to
646 call the function instead of going through the PLT. The result
647 is that we can avoid exporting the functions and we do not jump
648 PLT relocations in libc.so. */
649 void (*_dl_debug_printf) (const char *, ...)
650 __attribute__ ((__format__ (__printf__, 1, 2)));
651 int (internal_function *_dl_catch_error) (const char **, const char **,
652 bool *, void (*) (void *), void *);
653 void (internal_function *_dl_signal_error) (int, const char *, const char *,
655 void (*_dl_mcount) (ElfW(Addr) frompc, ElfW(Addr) selfpc);
656 lookup_t (internal_function *_dl_lookup_symbol_x) (const char *,
659 struct r_scope_elem *[],
660 const struct r_found_version *,
663 int (*_dl_check_caller) (const void *, enum allowmask);
664 void *(*_dl_open) (const char *file, int mode, const void *caller_dlopen,
665 Lmid_t nsid, int argc, char *argv[], char *env[]);
666 void (*_dl_close) (void *map);
668 /* List of auditing interfaces. */
669 struct audit_ifaces *_dl_audit;
670 unsigned int _dl_naudit;
672 /* 0 if internal pointer values should not be guarded, 1 if they should. */
673 EXTERN int _dl_pointer_guard;
675 # define __rtld_global_attribute__
677 # define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
678 extern struct rtld_global_ro _rtld_local_ro
679 attribute_relro __rtld_local_attribute__;
680 extern struct rtld_global_ro _rtld_global_ro
681 attribute_relro __rtld_global_attribute__;
682 # undef __rtld_local_attribute__
684 /* We cheat a bit here. We declare the variable as as const even
685 though it is at startup. */
686 extern const struct rtld_global_ro _rtld_global_ro
687 attribute_relro __rtld_global_attribute__;
689 # undef __rtld_global_attribute__
694 /* This is the initial value of GL(dl_error_catch_tsd).
695 A non-TLS libpthread will change it. */
696 extern void **_dl_initial_error_catch_tsd (void) __attribute__ ((const))
700 /* This is the initial value of GL(dl_make_stack_executable_hook).
701 A threads library can change it. */
702 extern int _dl_make_stack_executable (void **stack_endp) internal_function;
703 rtld_hidden_proto (_dl_make_stack_executable)
705 /* Variable pointing to the end of the stack (or close to it). This value
706 must be constant over the runtime of the application. Some programs
707 might use the variable which results in copy relocations on some
708 platforms. But this does not matter, ld.so can always use the local
710 extern void *__libc_stack_end attribute_relro;
711 rtld_hidden_proto (__libc_stack_end)
713 /* Parameters passed to the dynamic linker. */
714 extern int _dl_argc attribute_hidden attribute_relro;
715 extern char **_dl_argv
716 #ifndef DL_ARGV_NOT_RELRO
721 extern char **_dl_argv_internal attribute_hidden
722 # ifndef DL_ARGV_NOT_RELRO
726 # define rtld_progname (INTUSE(_dl_argv)[0])
728 # define rtld_progname _dl_argv[0]
731 /* Flag set at startup and cleared when the last initializer has run. */
732 extern int _dl_starting_up;
733 weak_extern (_dl_starting_up)
735 extern int _dl_starting_up_internal attribute_hidden;
738 /* OS-dependent function to open the zero-fill device. */
739 extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */
742 /* Write message on the debug file descriptor. The parameters are
743 interpreted as for a `printf' call. All the lines start with a
744 tag showing the PID. */
745 extern void _dl_debug_printf (const char *fmt, ...)
746 __attribute__ ((__format__ (__printf__, 1, 2))) attribute_hidden;
748 /* Write message on the debug file descriptor. The parameters are
749 interpreted as for a `printf' call. All the lines buf the first
750 start with a tag showing the PID. */
751 extern void _dl_debug_printf_c (const char *fmt, ...)
752 __attribute__ ((__format__ (__printf__, 1, 2)));
755 /* Write a message on the specified descriptor FD. The parameters are
756 interpreted as for a `printf' call. */
757 extern void _dl_dprintf (int fd, const char *fmt, ...)
758 __attribute__ ((__format__ (__printf__, 2, 3)))
761 /* Write a message on the specified descriptor standard output. The
762 parameters are interpreted as for a `printf' call. */
763 #define _dl_printf(fmt, args...) \
764 _dl_dprintf (STDOUT_FILENO, fmt, ##args)
766 /* Write a message on the specified descriptor standard error. The
767 parameters are interpreted as for a `printf' call. */
768 #define _dl_error_printf(fmt, args...) \
769 _dl_dprintf (STDERR_FILENO, fmt, ##args)
771 /* Write a message on the specified descriptor standard error and exit
772 the program. The parameters are interpreted as for a `printf' call. */
773 #define _dl_fatal_printf(fmt, args...) \
776 _dl_dprintf (STDERR_FILENO, fmt, ##args); \
782 /* This function is called by all the internal dynamic linker functions
783 when they encounter an error. ERRCODE is either an `errno' code or
784 zero; OBJECT is the name of the problematical shared object, or null if
785 it is a general problem; ERRSTRING is a string describing the specific
787 extern void _dl_signal_error (int errcode, const char *object,
788 const char *occurred, const char *errstring)
789 internal_function __attribute__ ((__noreturn__)) attribute_hidden;
791 /* Like _dl_signal_error, but may return when called in the context of
792 _dl_receive_error. */
793 extern void _dl_signal_cerror (int errcode, const char *object,
794 const char *occation, const char *errstring)
797 /* Call OPERATE, receiving errors from `dl_signal_cerror'. Unlike
798 `_dl_catch_error' the operation is resumed after the OPERATE
800 ARGS is passed as argument to OPERATE. */
801 extern void _dl_receive_error (receiver_fct fct, void (*operate) (void *),
806 /* Open the shared object NAME and map in its segments.
807 LOADER's DT_RPATH is used in searching for NAME.
808 If the object is already opened, returns its existing map.
809 For preloaded shared objects PRELOADED is set to a non-zero
810 value to allow additional security checks. */
811 extern struct link_map *_dl_map_object (struct link_map *loader,
812 const char *name, int preloaded,
813 int type, int trace_mode, int mode,
815 internal_function attribute_hidden;
817 /* Call _dl_map_object on the dependencies of MAP, and set up
818 MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously
819 loaded objects that will be inserted into MAP->l_searchlist after MAP
820 but before its dependencies. */
821 extern void _dl_map_object_deps (struct link_map *map,
822 struct link_map **preloads,
823 unsigned int npreloads, int trace_mode,
825 internal_function attribute_hidden;
827 /* Cache the locations of MAP's hash table. */
828 extern void _dl_setup_hash (struct link_map *map)
829 internal_function attribute_hidden;
832 /* Collect the directories in the search path for LOADER's dependencies.
833 The data structure is defined in <dlfcn.h>. If COUNTING is true,
834 SI->dls_cnt and SI->dls_size are set; if false, those must be as set
835 by a previous call with COUNTING set, and SI must point to SI->dls_size
836 bytes to be used in filling in the result. */
837 extern void _dl_rtld_di_serinfo (struct link_map *loader,
838 Dl_serinfo *si, bool counting)
842 /* Search loaded objects' symbol tables for a definition of the symbol
843 referred to by UNDEF. *SYM is the symbol table entry containing the
844 reference; it is replaced with the defining symbol, and the base load
845 address of the defining object is returned. SYMBOL_SCOPE is a
846 null-terminated list of object scopes to search; each object's
847 l_searchlist (i.e. the segment of the dependency tree starting at that
848 object) is searched in turn. REFERENCE_NAME should name the object
849 containing the reference; it is used in error messages.
850 TYPE_CLASS describes the type of symbol we are looking for. */
853 /* If necessary add dependency between user and provider object. */
854 DL_LOOKUP_ADD_DEPENDENCY = 1,
855 /* Return most recent version instead of default version for
856 unversioned lookup. */
857 DL_LOOKUP_RETURN_NEWEST = 2,
858 /* Set if dl_lookup* called with GSCOPE lock held. */
859 DL_LOOKUP_GSCOPE_LOCK = 4,
862 /* Lookup versioned symbol. */
863 extern lookup_t _dl_lookup_symbol_x (const char *undef,
864 struct link_map *undef_map,
865 const ElfW(Sym) **sym,
866 struct r_scope_elem *symbol_scope[],
867 const struct r_found_version *version,
868 int type_class, int flags,
869 struct link_map *skip_map)
870 internal_function attribute_hidden;
873 /* Look up symbol NAME in MAP's scope and return its run-time address. */
874 extern ElfW(Addr) _dl_symbol_value (struct link_map *map, const char *name)
877 /* Allocate a `struct link_map' for a new object being loaded,
878 and enter it into the _dl_main_map list. */
879 extern struct link_map *_dl_new_object (char *realname, const char *libname,
880 int type, struct link_map *loader,
881 int mode, Lmid_t nsid)
882 internal_function attribute_hidden;
884 /* Relocate the given object (if it hasn't already been).
885 SCOPE is passed to _dl_lookup_symbol in symbol lookups.
886 If LAZY is nonzero, don't relocate its PLT. */
887 extern void _dl_relocate_object (struct link_map *map,
888 struct r_scope_elem *scope[],
889 int lazy, int consider_profiling)
892 /* Protect PT_GNU_RELRO area. */
893 extern void _dl_protect_relro (struct link_map *map)
894 internal_function attribute_hidden;
896 /* Call _dl_signal_error with a message about an unhandled reloc type.
897 TYPE is the result of ELFW(R_TYPE) (r_info), i.e. an R_<CPU>_* value.
898 PLT is nonzero if this was a PLT reloc; it just affects the message. */
899 extern void _dl_reloc_bad_type (struct link_map *map,
900 unsigned int type, int plt)
901 internal_function __attribute__ ((__noreturn__));
903 /* Resolve conflicts if prelinking. */
904 extern void _dl_resolve_conflicts (struct link_map *l,
905 ElfW(Rela) *conflict,
906 ElfW(Rela) *conflictend);
908 /* Check the version dependencies of all objects available through
909 MAP. If VERBOSE print some more diagnostics. */
910 extern int _dl_check_all_versions (struct link_map *map, int verbose,
914 /* Check the version dependencies for MAP. If VERBOSE print some more
916 extern int _dl_check_map_versions (struct link_map *map, int verbose,
920 /* Initialize the object in SCOPE by calling the constructors with
921 ARGC, ARGV, and ENV as the parameters. */
922 extern void _dl_init (struct link_map *main_map, int argc, char **argv,
923 char **env) internal_function attribute_hidden;
925 /* Call the finalizer functions of all shared objects whose
926 initializer functions have completed. */
927 extern void _dl_fini (void) internal_function;
929 /* Sort array MAPS according to dependencies of the contained objects. */
930 extern void _dl_sort_fini (struct link_map *l, struct link_map **maps,
931 size_t nmaps, char *used, Lmid_t ns)
934 /* The dynamic linker calls this function before and having changing
935 any shared object mappings. The `r_state' member of `struct r_debug'
936 says what change is taking place. This function's address is
937 the value of the `r_brk' member. */
938 extern void _dl_debug_state (void);
939 rtld_hidden_proto (_dl_debug_state)
941 /* Initialize `struct r_debug' if it has not already been done. The
942 argument is the run-time load address of the dynamic linker, to be put
943 in the `r_ldbase' member. Returns the address of the structure. */
944 extern struct r_debug *_dl_debug_initialize (ElfW(Addr) ldbase, Lmid_t ns)
947 /* Initialize the basic data structure for the search paths. */
948 extern void _dl_init_paths (const char *library_path) internal_function;
950 /* Gather the information needed to install the profiling tables and start
952 extern void _dl_start_profile (void) internal_function attribute_hidden;
954 /* The actual functions used to keep book on the calls. */
955 extern void _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc);
956 extern void _dl_mcount_internal (ElfW(Addr) frompc, ElfW(Addr) selfpc)
959 /* This function is simply a wrapper around the _dl_mcount function
960 which does not require a FROMPC parameter since this is the
962 extern void _dl_mcount_wrapper (void *selfpc);
964 /* Show the members of the auxiliary array passed up from the kernel. */
965 extern void _dl_show_auxv (void) internal_function;
967 /* Return all environment variables starting with `LD_', one after the
969 extern char *_dl_next_ld_env_entry (char ***position) internal_function;
971 /* Return an array with the names of the important hardware capabilities. */
972 extern const struct r_strlenpair *_dl_important_hwcaps (const char *platform,
975 size_t *max_capstrlen)
978 /* Look up NAME in ld.so.cache and return the file name stored there,
979 or null if none is found. */
980 extern const char *_dl_load_cache_lookup (const char *name)
983 /* If the system does not support MAP_COPY we cannot leave the file open
984 all the time since this would create problems when the file is replaced.
985 Therefore we provide this function to close the file and open it again
987 extern void _dl_unload_cache (void) attribute_hidden;
989 /* System-dependent function to read a file's whole contents in the
990 most convenient manner available. *SIZEP gets the size of the
991 file. On error MAP_FAILED is returned. */
992 extern void *_dl_sysdep_read_whole_file (const char *file, size_t *sizep,
994 internal_function attribute_hidden;
996 /* System-specific function to do initial startup for the dynamic linker.
997 After this, file access calls and getenv must work. This is responsible
998 for setting __libc_enable_secure if we need to be secure (e.g. setuid),
999 and for setting _dl_argc and _dl_argv, and then calling _dl_main. */
1000 extern ElfW(Addr) _dl_sysdep_start (void **start_argptr,
1001 void (*dl_main) (const ElfW(Phdr) *phdr,
1003 ElfW(Addr) *user_entry))
1006 extern void _dl_sysdep_start_cleanup (void)
1007 internal_function attribute_hidden;
1010 /* Determine next available module ID. */
1011 extern size_t _dl_next_tls_modid (void) internal_function attribute_hidden;
1013 /* Calculate offset of the TLS blocks in the static TLS block. */
1014 extern void _dl_determine_tlsoffset (void) internal_function attribute_hidden;
1016 /* Set up the data structures for TLS, when they were not set up at startup.
1017 Returns nonzero on malloc failure.
1018 This is called from _dl_map_object_from_fd or by libpthread. */
1019 extern int _dl_tls_setup (void) internal_function;
1020 rtld_hidden_proto (_dl_tls_setup)
1022 /* Allocate memory for static TLS block (unless MEM is nonzero) and dtv. */
1023 extern void *_dl_allocate_tls (void *mem) internal_function;
1024 rtld_hidden_proto (_dl_allocate_tls)
1026 /* Get size and alignment requirements of the static TLS block. */
1027 extern void _dl_get_tls_static_info (size_t *sizep, size_t *alignp)
1030 extern void _dl_allocate_static_tls (struct link_map *map)
1031 internal_function attribute_hidden;
1033 /* These are internal entry points to the two halves of _dl_allocate_tls,
1034 only used within rtld.c itself at startup time. */
1035 extern void *_dl_allocate_tls_storage (void)
1036 internal_function attribute_hidden;
1037 extern void *_dl_allocate_tls_init (void *) internal_function;
1038 rtld_hidden_proto (_dl_allocate_tls_init)
1040 /* Deallocate memory allocated with _dl_allocate_tls. */
1041 extern void _dl_deallocate_tls (void *tcb, bool dealloc_tcb) internal_function;
1042 rtld_hidden_proto (_dl_deallocate_tls)
1044 extern void _dl_nothread_init_static_tls (struct link_map *) attribute_hidden;
1046 /* Find origin of the executable. */
1047 extern const char *_dl_get_origin (void) attribute_hidden;
1050 extern size_t _dl_dst_count (const char *name, int is_path) attribute_hidden;
1052 /* Substitute DST values. */
1053 extern char *_dl_dst_substitute (struct link_map *l, const char *name,
1054 char *result, int is_path) attribute_hidden;
1056 /* Check validity of the caller. */
1057 extern int _dl_check_caller (const void *caller, enum allowmask mask)
1060 /* Open the shared object NAME, relocate it, and run its initializer if it
1061 hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If
1062 the object is already opened, returns its existing map. */
1063 extern void *_dl_open (const char *name, int mode, const void *caller,
1064 Lmid_t nsid, int argc, char *argv[], char *env[])
1067 /* Free or queue for freeing scope OLD. If other threads might be
1068 in the middle of _dl_fixup, _dl_profile_fixup or dl*sym using the
1069 old scope, OLD can't be freed until no thread is using it. */
1070 extern int _dl_scope_free (void *) attribute_hidden;
1072 /* Add module to slot information data. */
1073 extern void _dl_add_to_slotinfo (struct link_map *l) attribute_hidden;
1075 /* Update slot information data for at least the generation of the
1076 module with the given index. */
1077 extern struct link_map *_dl_update_slotinfo (unsigned long int req_modid);
1079 /* Look up the module's TLS block as for __tls_get_addr,
1080 but never touch anything. Return null if it's not allocated yet. */
1081 extern void *_dl_tls_get_addr_soft (struct link_map *l) internal_function;
1083 extern int _dl_addr_inside_object (struct link_map *l, const ElfW(Addr) addr)
1084 internal_function attribute_hidden;
1088 #endif /* ldsodefs.h */