1 /* Run-time dynamic linker data structures for loaded ELF shared objects.
2 Copyright (C) 1995-2014 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, see
17 <http://www.gnu.org/licenses/>. */
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 #define VERSYMIDX(sym) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (sym))
46 #define VALIDX(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
47 + DT_EXTRANUM + DT_VALTAGIDX (tag))
48 #define ADDRIDX(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
49 + DT_EXTRANUM + DT_VALNUM + DT_ADDRTAGIDX (tag))
51 /* We use this macro to refer to ELF types independent of the native wordsize.
52 `ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'. */
53 #define ELFW(type) _ElfW (ELF, __ELF_NATIVE_CLASS, type)
55 /* All references to the value of l_info[DT_PLTGOT],
56 l_info[DT_STRTAB], l_info[DT_SYMTAB], l_info[DT_RELA],
57 l_info[DT_REL], l_info[DT_JMPREL], and l_info[VERSYMIDX (DT_VERSYM)]
58 have to be accessed via the D_PTR macro. The macro is needed since for
59 most architectures the entry is already relocated - but for some not
60 and we need to relocate at access time. */
61 #ifdef DL_RO_DYN_SECTION
62 # define D_PTR(map, i) ((map)->i->d_un.d_ptr + (map)->l_addr)
64 # define D_PTR(map, i) (map)->i->d_un.d_ptr
67 /* Result of the lookup functions and how to retrieve the base address. */
68 typedef struct link_map
*lookup_t
;
69 #define LOOKUP_VALUE(map) map
70 #define LOOKUP_VALUE_ADDRESS(map) ((map) ? (map)->l_addr : 0)
72 /* On some architectures a pointer to a function is not just a pointer
73 to the actual code of the function but rather an architecture
74 specific descriptor. */
75 #ifndef ELF_FUNCTION_PTR_IS_SPECIAL
76 # define DL_SYMBOL_ADDRESS(map, ref) \
77 (void *) (LOOKUP_VALUE_ADDRESS (map) + ref->st_value)
78 # define DL_LOOKUP_ADDRESS(addr) ((ElfW(Addr)) (addr))
79 # define DL_CALL_DT_INIT(map, start, argc, argv, env) \
80 ((init_t) (start)) (argc, argv, env)
81 # define DL_CALL_DT_FINI(map, start) ((fini_t) (start)) ()
84 /* On some architectures dladdr can't use st_size of all symbols this way. */
85 #define DL_ADDR_SYM_MATCH(L, SYM, MATCHSYM, ADDR) \
86 ((ADDR) >= (L)->l_addr + (SYM)->st_value \
87 && ((((SYM)->st_shndx == SHN_UNDEF || (SYM)->st_size == 0) \
88 && (ADDR) == (L)->l_addr + (SYM)->st_value) \
89 || (ADDR) < (L)->l_addr + (SYM)->st_value + (SYM)->st_size) \
90 && ((MATCHSYM) == NULL || (MATCHSYM)->st_value < (SYM)->st_value))
92 /* Unmap a loaded object, called by _dl_close (). */
93 #ifndef DL_UNMAP_IS_SPECIAL
94 # define DL_UNMAP(map) \
95 __munmap ((void *) (map)->l_map_start, \
96 (map)->l_map_end - (map)->l_map_start)
99 /* By default we do not need special support to initialize DSOs loaded
100 by statically linked binaries. */
101 #ifndef DL_STATIC_INIT
102 # define DL_STATIC_INIT(map)
105 /* Reloc type classes as returned by elf_machine_type_class().
106 ELF_RTYPE_CLASS_PLT means this reloc should not be satisfied by
107 some PLT symbol, ELF_RTYPE_CLASS_COPY means this reloc should not be
108 satisfied by any symbol in the executable. Some architectures do
109 not support copy relocations. In this case we define the macro to
110 zero so that the code for handling them gets automatically optimized
112 #define ELF_RTYPE_CLASS_PLT 1
113 #ifndef DL_NO_COPY_RELOCS
114 # define ELF_RTYPE_CLASS_COPY 2
116 # define ELF_RTYPE_CLASS_COPY 0
119 /* ELF uses the PF_x macros to specify the segment permissions, mmap
120 uses PROT_xxx. In most cases the three macros have the values 1, 2,
121 and 3 but not in a matching order. The following macros allows
122 converting from the PF_x values to PROT_xxx values. */
124 ((PROT_READ << (PF_R * 4)) \
125 | (PROT_WRITE << (PF_W * 4)) \
126 | (PROT_EXEC << (PF_X * 4)) \
127 | ((PROT_READ | PROT_WRITE) << ((PF_R | PF_W) * 4)) \
128 | ((PROT_READ | PROT_EXEC) << ((PF_R | PF_X) * 4)) \
129 | ((PROT_WRITE | PROT_EXEC) << (PF_W | PF_X) * 4) \
130 | ((PROT_READ | PROT_WRITE | PROT_EXEC) << ((PF_R | PF_W | PF_X) * 4)))
132 /* The filename itself, or the main program name, if available. */
133 #define DSO_FILENAME(name) ((name)[0] ? (name) \
134 : (rtld_progname ?: "<main program>"))
136 #define RTLD_PROGNAME (rtld_progname ?: "<program name unknown>")
138 /* For the version handling we need an array with only names and their
140 struct r_found_version
146 const char *filename
;
149 /* We want to cache information about the searches for shared objects. */
151 enum r_dir_status
{ unknown
, nonexisting
, existing
};
153 struct r_search_path_elem
155 /* This link is only used in the `all_dirs' member of `r_search_path'. */
156 struct r_search_path_elem
*next
;
158 /* Strings saying where the definition came from. */
162 /* Basename for this search path element. The string must end with
163 a slash character. */
167 enum r_dir_status status
[0];
177 /* A data structure for a simple single linked list of strings. */
180 const char *name
; /* Name requested (before search). */
181 struct libname_list
*next
; /* Link to next name for this object. */
182 int dont_free
; /* Flag whether this element should be freed
183 if the object is not entirely unloaded. */
187 /* Bit masks for the objects which valid callers can come from to
188 functions with restricted interface. */
193 allow_libpthread
= 4,
200 void (*activity
) (uintptr_t *, unsigned int);
201 char *(*objsearch
) (const char *, uintptr_t *, unsigned int);
202 unsigned int (*objopen
) (struct link_map
*, Lmid_t
, uintptr_t *);
203 void (*preinit
) (uintptr_t *);
206 uintptr_t (*symbind32
) (Elf32_Sym
*, unsigned int, uintptr_t *,
207 uintptr_t *, unsigned int *, const char *);
208 uintptr_t (*symbind64
) (Elf64_Sym
*, unsigned int, uintptr_t *,
209 uintptr_t *, unsigned int *, const char *);
213 #ifdef ARCH_PLTENTER_MEMBERS
214 ARCH_PLTENTER_MEMBERS
;
219 #ifdef ARCH_PLTEXIT_MEMBERS
220 ARCH_PLTEXIT_MEMBERS
;
223 unsigned int (*objclose
) (uintptr_t *);
225 struct audit_ifaces
*next
;
229 /* Test whether given NAME matches any of the names of the given object. */
230 extern int _dl_name_match_p (const char *__name
, const struct link_map
*__map
)
233 /* Compute next higher prime number. */
234 extern unsigned long int _dl_higher_prime_number (unsigned long int n
)
237 /* Function used as argument for `_dl_receive_error' function. The
238 arguments are the error code, error string, and the objname the
239 error occurred in. */
240 typedef void (*receiver_fct
) (int, const char *, const char *);
242 /* Internal functions of the run-time dynamic linker.
243 These can be accessed if you link again the dynamic linker
244 as a shared library, as in `-lld' or `/lib/ld.so' explicitly;
245 but are not normally of interest to user programs.
247 The `-ldl' library functions in <dlfcn.h> provide a simple
248 user interface to run-time dynamic linking. */
252 # define EXTERN extern
253 # define GL(name) _##name
257 # define GL(name) _rtld_local._##name
259 # define GL(name) _rtld_global._##name
264 /* Don't change the order of the following elements. 'dl_loaded'
265 must remain the first element. Forever. */
267 /* Non-shared code has no support for multiple namespaces. */
273 EXTERN
struct link_namespaces
275 /* A pointer to the map for the main map. */
276 struct link_map
*_ns_loaded
;
277 /* Number of object in the _dl_loaded list. */
278 unsigned int _ns_nloaded
;
279 /* Direct pointer to the searchlist of the main object. */
280 struct r_scope_elem
*_ns_main_searchlist
;
281 /* This is zero at program start to signal that the global scope map is
282 allocated by rtld. Later it keeps the size of the map. It might be
283 reset if in _dl_close if the last global object is removed. */
284 size_t _ns_global_scope_alloc
;
285 /* Search table for unique objects. */
286 struct unique_sym_table
288 __rtld_lock_define_recursive (, lock
)
293 const ElfW(Sym
) *sym
;
294 const struct link_map
*map
;
298 void (*free
) (void *);
299 } _ns_unique_sym_table
;
300 /* Keep track of changes to each namespace' list. */
301 struct r_debug _ns_debug
;
303 /* One higher than index of last used namespace. */
304 EXTERN
size_t _dl_nns
;
306 /* During the program run we must not modify the global data of
307 loaded shared object simultanously in two threads. Therefore we
308 protect `_dl_open' and `_dl_close' in dl-close.c.
310 This must be a recursive lock since the initializer function of
311 the loaded object might as well require a call to this function.
312 At this time it is not anymore a problem to modify the tables. */
313 __rtld_lock_define_recursive (EXTERN
, _dl_load_lock
)
314 /* This lock is used to keep __dl_iterate_phdr from inspecting the
315 list of loaded objects while an object is added to or removed
317 __rtld_lock_define_recursive (EXTERN
, _dl_load_write_lock
)
319 /* Incremented whenever something may have been added to dl_loaded. */
320 EXTERN
unsigned long long _dl_load_adds
;
322 /* The object to be initialized first. */
323 EXTERN
struct link_map
*_dl_initfirst
;
325 #if HP_TIMING_AVAIL || HP_SMALL_TIMING_AVAIL
326 /* Start time on CPU clock. */
327 EXTERN hp_timing_t _dl_cpuclock_offset
;
330 /* Map of shared object to be profiled. */
331 EXTERN
struct link_map
*_dl_profile_map
;
333 /* Counters for the number of relocations performed. */
334 EXTERN
unsigned long int _dl_num_relocations
;
335 EXTERN
unsigned long int _dl_num_cache_relocations
;
337 /* List of search directories. */
338 EXTERN
struct r_search_path_elem
*_dl_all_dirs
;
340 #ifdef _LIBC_REENTRANT
341 EXTERN
void **(*_dl_error_catch_tsd
) (void) __attribute__ ((const));
344 /* Structure describing the dynamic linker itself. We need to
345 reserve memory for the data the audit libraries need. */
346 EXTERN
struct link_map _dl_rtld_map
;
348 struct auditstate audit_data
[DL_NNS
];
351 #if defined SHARED && defined _LIBC_REENTRANT \
352 && defined __rtld_lock_default_lock_recursive
353 EXTERN
void (*_dl_rtld_lock_recursive
) (void *);
354 EXTERN
void (*_dl_rtld_unlock_recursive
) (void *);
357 /* If loading a shared object requires that we make the stack executable
358 when it was not, we do it by calling this function.
359 It returns an errno code or zero on success. */
360 EXTERN
int (*_dl_make_stack_executable_hook
) (void **) internal_function
;
362 /* Prevailing state of the stack, PF_X indicating it's executable. */
363 EXTERN
ElfW(Word
) _dl_stack_flags
;
365 /* Flag signalling whether there are gaps in the module ID allocation. */
366 EXTERN
bool _dl_tls_dtv_gaps
;
367 /* Highest dtv index currently needed. */
368 EXTERN
size_t _dl_tls_max_dtv_idx
;
369 /* Information about the dtv slots. */
370 EXTERN
struct dtv_slotinfo_list
373 struct dtv_slotinfo_list
*next
;
377 struct link_map
*map
;
379 } *_dl_tls_dtv_slotinfo_list
;
380 /* Number of modules in the static TLS block. */
381 EXTERN
size_t _dl_tls_static_nelem
;
382 /* Size of the static TLS block. */
383 EXTERN
size_t _dl_tls_static_size
;
384 /* Size actually allocated in the static TLS block. */
385 EXTERN
size_t _dl_tls_static_used
;
386 /* Alignment requirement of the static TLS block. */
387 EXTERN
size_t _dl_tls_static_align
;
389 /* Number of additional entries in the slotinfo array of each slotinfo
390 list element. A large number makes it almost certain take we never
391 have to iterate beyond the first element in the slotinfo list. */
392 #define TLS_SLOTINFO_SURPLUS (62)
394 /* Number of additional slots in the dtv allocated. */
395 #define DTV_SURPLUS (14)
397 /* Initial dtv of the main thread, not allocated with normal malloc. */
398 EXTERN
void *_dl_initial_dtv
;
399 /* Generation counter for the dtv. */
400 EXTERN
size_t _dl_tls_generation
;
402 EXTERN
void (*_dl_init_static_tls
) (struct link_map
*);
404 EXTERN
void (*_dl_wait_lookup_done
) (void);
406 /* Scopes to free after next THREAD_GSCOPE_WAIT (). */
407 EXTERN
struct dl_scope_free_list
411 } *_dl_scope_free_list
;
414 # define __rtld_global_attribute__
416 # ifdef HAVE_SDATA_SECTION
417 # define __rtld_local_attribute__ \
418 __attribute__ ((visibility ("hidden"), section (".sdata")))
419 # undef __rtld_global_attribute__
420 # define __rtld_global_attribute__ __attribute__ ((section (".sdata")))
422 # define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
424 extern struct rtld_global _rtld_local __rtld_local_attribute__
;
425 # undef __rtld_local_attribute__
427 extern struct rtld_global _rtld_global __rtld_global_attribute__
;
428 # undef __rtld_global_attribute__
432 # define GLRO(name) _##name
435 # define GLRO(name) _rtld_local_ro._##name
437 # define GLRO(name) _rtld_global_ro._##name
439 struct rtld_global_ro
443 /* If nonzero the appropriate debug information is printed. */
444 EXTERN
int _dl_debug_mask
;
445 #define DL_DEBUG_LIBS (1 << 0)
446 #define DL_DEBUG_IMPCALLS (1 << 1)
447 #define DL_DEBUG_BINDINGS (1 << 2)
448 #define DL_DEBUG_SYMBOLS (1 << 3)
449 #define DL_DEBUG_VERSIONS (1 << 4)
450 #define DL_DEBUG_RELOC (1 << 5)
451 #define DL_DEBUG_FILES (1 << 6)
452 #define DL_DEBUG_STATISTICS (1 << 7)
453 #define DL_DEBUG_UNUSED (1 << 8)
454 #define DL_DEBUG_SCOPES (1 << 9)
455 /* These two are used only internally. */
456 #define DL_DEBUG_HELP (1 << 10)
457 #define DL_DEBUG_PRELINK (1 << 11)
460 EXTERN
unsigned int _dl_osversion
;
462 EXTERN
const char *_dl_platform
;
463 EXTERN
size_t _dl_platformlen
;
465 /* Cached value of `getpagesize ()'. */
466 EXTERN
size_t _dl_pagesize
;
468 /* Do we read from ld.so.cache? */
469 EXTERN
int _dl_inhibit_cache
;
471 /* Copy of the content of `_dl_main_searchlist' at startup time. */
472 EXTERN
struct r_scope_elem _dl_initial_searchlist
;
474 /* CLK_TCK as reported by the kernel. */
475 EXTERN
int _dl_clktck
;
477 /* If nonzero print warnings messages. */
478 EXTERN
int _dl_verbose
;
480 /* File descriptor to write debug messages to. */
481 EXTERN
int _dl_debug_fd
;
483 /* Do we do lazy relocations? */
486 /* Nonzero if runtime lookups should not update the .got/.plt. */
487 EXTERN
int _dl_bind_not
;
489 /* Nonzero if references should be treated as weak during runtime
491 EXTERN
int _dl_dynamic_weak
;
493 /* Default floating-point control word. */
494 EXTERN fpu_control_t _dl_fpu_control
;
496 /* Expected cache ID. */
497 EXTERN
int _dl_correct_cache_id
;
499 /* Mask for hardware capabilities that are available. */
500 EXTERN
uint64_t _dl_hwcap
;
502 /* Mask for important hardware capabilities we honour. */
503 EXTERN
uint64_t _dl_hwcap_mask
;
505 /* Pointer to the auxv list supplied to the program at startup. */
506 EXTERN
ElfW(auxv_t
) *_dl_auxv
;
508 /* Get architecture specific definitions. */
509 #define PROCINFO_DECL
510 #ifndef PROCINFO_CLASS
511 # define PROCINFO_CLASS EXTERN
513 #include <dl-procinfo.c>
515 /* Names of shared object for which the RPATH should be ignored. */
516 EXTERN
const char *_dl_inhibit_rpath
;
518 /* Location of the binary. */
519 EXTERN
const char *_dl_origin_path
;
521 /* -1 if the dynamic linker should honor library load bias,
522 0 if not, -2 use the default (honor biases for normal
523 binaries, don't honor for PIEs). */
524 EXTERN
ElfW(Addr
) _dl_use_load_bias
;
526 /* Name of the shared object to be profiled (if any). */
527 EXTERN
const char *_dl_profile
;
528 /* Filename of the output file. */
529 EXTERN
const char *_dl_profile_output
;
530 /* Name of the object we want to trace the prelinking. */
531 EXTERN
const char *_dl_trace_prelink
;
532 /* Map of shared object to be prelink traced. */
533 EXTERN
struct link_map
*_dl_trace_prelink_map
;
535 /* All search directories defined at startup. */
536 EXTERN
struct r_search_path_elem
*_dl_init_all_dirs
;
538 #if HP_TIMING_AVAIL || HP_SMALL_TIMING_AVAIL
539 /* Overhead of a high-precision timing measurement. */
540 EXTERN hp_timing_t _dl_hp_timing_overhead
;
543 #ifdef NEED_DL_SYSINFO
544 /* Syscall handling improvements. This is very specific to x86. */
545 EXTERN
uintptr_t _dl_sysinfo
;
548 #ifdef NEED_DL_SYSINFO_DSO
549 /* The vsyscall page is a virtual DSO pre-mapped by the kernel.
550 This points to its ELF header. */
551 EXTERN
const ElfW(Ehdr
) *_dl_sysinfo_dso
;
553 /* At startup time we set up the normal DSO data structure for it,
554 and this points to it. */
555 EXTERN
struct link_map
*_dl_sysinfo_map
;
558 /* Mask for more hardware capabilities that are available on some
560 EXTERN
uint64_t _dl_hwcap2
;
563 /* We add a function table to _rtld_global which is then used to
564 call the function instead of going through the PLT. The result
565 is that we can avoid exporting the functions and we do not jump
566 PLT relocations in libc.so. */
567 void (*_dl_debug_printf
) (const char *, ...)
568 __attribute__ ((__format__ (__printf__
, 1, 2)));
569 int (internal_function
*_dl_catch_error
) (const char **, const char **,
570 bool *, void (*) (void *), void *);
571 void (internal_function
*_dl_signal_error
) (int, const char *, const char *,
573 void (*_dl_mcount
) (ElfW(Addr
) frompc
, ElfW(Addr
) selfpc
);
574 lookup_t (internal_function
*_dl_lookup_symbol_x
) (const char *,
577 struct r_scope_elem
*[],
578 const struct r_found_version
*,
581 int (*_dl_check_caller
) (const void *, enum allowmask
);
582 void *(*_dl_open
) (const char *file
, int mode
, const void *caller_dlopen
,
583 Lmid_t nsid
, int argc
, char *argv
[], char *env
[]);
584 void (*_dl_close
) (void *map
);
585 void *(*_dl_tls_get_addr_soft
) (struct link_map
*);
586 #ifdef HAVE_DL_DISCOVER_OSVERSION
587 int (*_dl_discover_osversion
) (void);
590 /* List of auditing interfaces. */
591 struct audit_ifaces
*_dl_audit
;
592 unsigned int _dl_naudit
;
594 /* 0 if internal pointer values should not be guarded, 1 if they should. */
595 EXTERN
int _dl_pointer_guard
;
597 # define __rtld_global_attribute__
599 # define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
600 extern struct rtld_global_ro _rtld_local_ro
601 attribute_relro __rtld_local_attribute__
;
602 extern struct rtld_global_ro _rtld_global_ro
603 attribute_relro __rtld_global_attribute__
;
604 # undef __rtld_local_attribute__
606 /* We cheat a bit here. We declare the variable as as const even
607 though it is at startup. */
608 extern const struct rtld_global_ro _rtld_global_ro
609 attribute_relro __rtld_global_attribute__
;
611 # undef __rtld_global_attribute__
616 /* dl-support.c defines these and initializes them early on. */
617 extern const ElfW(Phdr
) *_dl_phdr
;
618 extern size_t _dl_phnum
;
622 /* This is the initial value of GL(dl_error_catch_tsd).
623 A non-TLS libpthread will change it. */
624 extern void **_dl_initial_error_catch_tsd (void) __attribute__ ((const))
628 /* This is the initial value of GL(dl_make_stack_executable_hook).
629 A threads library can change it. */
630 extern int _dl_make_stack_executable (void **stack_endp
) internal_function
;
631 rtld_hidden_proto (_dl_make_stack_executable
)
633 /* Variable pointing to the end of the stack (or close to it). This value
634 must be constant over the runtime of the application. Some programs
635 might use the variable which results in copy relocations on some
636 platforms. But this does not matter, ld.so can always use the local
638 extern void *__libc_stack_end
639 #ifndef LIBC_STACK_END_NOT_RELRO
643 rtld_hidden_proto (__libc_stack_end
)
645 /* Parameters passed to the dynamic linker. */
646 extern int _dl_argc attribute_hidden attribute_relro
;
647 extern char **_dl_argv
648 #ifndef DL_ARGV_NOT_RELRO
653 extern unsigned int _dl_skip_args attribute_hidden
654 # ifndef DL_ARGV_NOT_RELRO
658 extern unsigned int _dl_skip_args_internal attribute_hidden
659 # ifndef DL_ARGV_NOT_RELRO
663 extern char **_dl_argv_internal attribute_hidden
664 # ifndef DL_ARGV_NOT_RELRO
668 # define rtld_progname (INTUSE(_dl_argv)[0])
670 # define rtld_progname _dl_argv[0]
673 /* Flag set at startup and cleared when the last initializer has run. */
674 extern int _dl_starting_up
;
675 weak_extern (_dl_starting_up
)
677 extern int _dl_starting_up_internal attribute_hidden
;
680 /* Random data provided by the kernel. */
681 extern void *_dl_random attribute_hidden attribute_relro
;
683 /* OS-dependent function to open the zero-fill device. */
684 extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */
687 /* Write message on the debug file descriptor. The parameters are
688 interpreted as for a `printf' call. All the lines start with a
689 tag showing the PID. */
690 extern void _dl_debug_printf (const char *fmt
, ...)
691 __attribute__ ((__format__ (__printf__
, 1, 2))) attribute_hidden
;
693 /* Write message on the debug file descriptor. The parameters are
694 interpreted as for a `printf' call. All the lines buf the first
695 start with a tag showing the PID. */
696 extern void _dl_debug_printf_c (const char *fmt
, ...)
697 __attribute__ ((__format__ (__printf__
, 1, 2)));
700 /* Write a message on the specified descriptor FD. The parameters are
701 interpreted as for a `printf' call. */
702 extern void _dl_dprintf (int fd
, const char *fmt
, ...)
703 __attribute__ ((__format__ (__printf__
, 2, 3)))
706 /* Write a message on the specified descriptor standard output. The
707 parameters are interpreted as for a `printf' call. */
708 #define _dl_printf(fmt, args...) \
709 _dl_dprintf (STDOUT_FILENO, fmt, ##args)
711 /* Write a message on the specified descriptor standard error. The
712 parameters are interpreted as for a `printf' call. */
713 #define _dl_error_printf(fmt, args...) \
714 _dl_dprintf (STDERR_FILENO, fmt, ##args)
716 /* Write a message on the specified descriptor standard error and exit
717 the program. The parameters are interpreted as for a `printf' call. */
718 #define _dl_fatal_printf(fmt, args...) \
721 _dl_dprintf (STDERR_FILENO, fmt, ##args); \
727 /* This function is called by all the internal dynamic linker functions
728 when they encounter an error. ERRCODE is either an `errno' code or
729 zero; OBJECT is the name of the problematical shared object, or null if
730 it is a general problem; ERRSTRING is a string describing the specific
732 extern void _dl_signal_error (int errcode
, const char *object
,
733 const char *occurred
, const char *errstring
)
734 internal_function
__attribute__ ((__noreturn__
)) attribute_hidden
;
736 /* Like _dl_signal_error, but may return when called in the context of
737 _dl_receive_error. */
738 extern void _dl_signal_cerror (int errcode
, const char *object
,
739 const char *occation
, const char *errstring
)
742 /* Call OPERATE, receiving errors from `dl_signal_cerror'. Unlike
743 `_dl_catch_error' the operation is resumed after the OPERATE
745 ARGS is passed as argument to OPERATE. */
746 extern void _dl_receive_error (receiver_fct fct
, void (*operate
) (void *),
751 /* Open the shared object NAME and map in its segments.
752 LOADER's DT_RPATH is used in searching for NAME.
753 If the object is already opened, returns its existing map. */
754 extern struct link_map
*_dl_map_object (struct link_map
*loader
,
756 int type
, int trace_mode
, int mode
,
758 internal_function attribute_hidden
;
760 /* Call _dl_map_object on the dependencies of MAP, and set up
761 MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously
762 loaded objects that will be inserted into MAP->l_searchlist after MAP
763 but before its dependencies. */
764 extern void _dl_map_object_deps (struct link_map
*map
,
765 struct link_map
**preloads
,
766 unsigned int npreloads
, int trace_mode
,
768 internal_function attribute_hidden
;
770 /* Cache the locations of MAP's hash table. */
771 extern void _dl_setup_hash (struct link_map
*map
)
772 internal_function attribute_hidden
;
775 /* Collect the directories in the search path for LOADER's dependencies.
776 The data structure is defined in <dlfcn.h>. If COUNTING is true,
777 SI->dls_cnt and SI->dls_size are set; if false, those must be as set
778 by a previous call with COUNTING set, and SI must point to SI->dls_size
779 bytes to be used in filling in the result. */
780 extern void _dl_rtld_di_serinfo (struct link_map
*loader
,
781 Dl_serinfo
*si
, bool counting
)
785 /* Search loaded objects' symbol tables for a definition of the symbol
786 referred to by UNDEF. *SYM is the symbol table entry containing the
787 reference; it is replaced with the defining symbol, and the base load
788 address of the defining object is returned. SYMBOL_SCOPE is a
789 null-terminated list of object scopes to search; each object's
790 l_searchlist (i.e. the segment of the dependency tree starting at that
791 object) is searched in turn. REFERENCE_NAME should name the object
792 containing the reference; it is used in error messages.
793 TYPE_CLASS describes the type of symbol we are looking for. */
796 /* If necessary add dependency between user and provider object. */
797 DL_LOOKUP_ADD_DEPENDENCY
= 1,
798 /* Return most recent version instead of default version for
799 unversioned lookup. */
800 DL_LOOKUP_RETURN_NEWEST
= 2,
801 /* Set if dl_lookup* called with GSCOPE lock held. */
802 DL_LOOKUP_GSCOPE_LOCK
= 4,
805 /* Lookup versioned symbol. */
806 extern lookup_t
_dl_lookup_symbol_x (const char *undef
,
807 struct link_map
*undef_map
,
808 const ElfW(Sym
) **sym
,
809 struct r_scope_elem
*symbol_scope
[],
810 const struct r_found_version
*version
,
811 int type_class
, int flags
,
812 struct link_map
*skip_map
)
813 internal_function attribute_hidden
;
816 /* Look up symbol NAME in MAP's scope and return its run-time address. */
817 extern ElfW(Addr
) _dl_symbol_value (struct link_map
*map
, const char *name
)
820 /* Add the new link_map NEW to the end of the namespace list. */
821 extern void _dl_add_to_namespace_list (struct link_map
*new, Lmid_t nsid
)
822 internal_function attribute_hidden
;
824 /* Allocate a `struct link_map' for a new object being loaded. */
825 extern struct link_map
*_dl_new_object (char *realname
, const char *libname
,
826 int type
, struct link_map
*loader
,
827 int mode
, Lmid_t nsid
)
828 internal_function attribute_hidden
;
830 /* Relocate the given object (if it hasn't already been).
831 SCOPE is passed to _dl_lookup_symbol in symbol lookups.
832 If RTLD_LAZY is set in RELOC-MODE, don't relocate its PLT. */
833 extern void _dl_relocate_object (struct link_map
*map
,
834 struct r_scope_elem
*scope
[],
835 int reloc_mode
, int consider_profiling
)
838 /* Protect PT_GNU_RELRO area. */
839 extern void _dl_protect_relro (struct link_map
*map
)
840 internal_function attribute_hidden
;
842 /* Call _dl_signal_error with a message about an unhandled reloc type.
843 TYPE is the result of ELFW(R_TYPE) (r_info), i.e. an R_<CPU>_* value.
844 PLT is nonzero if this was a PLT reloc; it just affects the message. */
845 extern void _dl_reloc_bad_type (struct link_map
*map
,
846 unsigned int type
, int plt
)
847 internal_function
__attribute__ ((__noreturn__
));
849 /* Resolve conflicts if prelinking. */
850 extern void _dl_resolve_conflicts (struct link_map
*l
,
851 ElfW(Rela
) *conflict
,
852 ElfW(Rela
) *conflictend
);
854 /* Check the version dependencies of all objects available through
855 MAP. If VERBOSE print some more diagnostics. */
856 extern int _dl_check_all_versions (struct link_map
*map
, int verbose
,
860 /* Check the version dependencies for MAP. If VERBOSE print some more
862 extern int _dl_check_map_versions (struct link_map
*map
, int verbose
,
866 /* Initialize the object in SCOPE by calling the constructors with
867 ARGC, ARGV, and ENV as the parameters. */
868 extern void _dl_init (struct link_map
*main_map
, int argc
, char **argv
,
869 char **env
) internal_function attribute_hidden
;
871 /* Call the finalizer functions of all shared objects whose
872 initializer functions have completed. */
873 extern void _dl_fini (void) internal_function
;
875 /* Sort array MAPS according to dependencies of the contained objects. */
876 extern void _dl_sort_fini (struct link_map
**maps
, size_t nmaps
, char *used
,
880 /* The dynamic linker calls this function before and having changing
881 any shared object mappings. The `r_state' member of `struct r_debug'
882 says what change is taking place. This function's address is
883 the value of the `r_brk' member. */
884 extern void _dl_debug_state (void);
885 rtld_hidden_proto (_dl_debug_state
)
887 /* Initialize `struct r_debug' if it has not already been done. The
888 argument is the run-time load address of the dynamic linker, to be put
889 in the `r_ldbase' member. Returns the address of the structure. */
890 extern struct r_debug
*_dl_debug_initialize (ElfW(Addr
) ldbase
, Lmid_t ns
)
893 /* Initialize the basic data structure for the search paths. */
894 extern void _dl_init_paths (const char *library_path
) internal_function
;
896 /* Gather the information needed to install the profiling tables and start
898 extern void _dl_start_profile (void) internal_function attribute_hidden
;
900 /* The actual functions used to keep book on the calls. */
901 extern void _dl_mcount (ElfW(Addr
) frompc
, ElfW(Addr
) selfpc
);
902 extern void _dl_mcount_internal (ElfW(Addr
) frompc
, ElfW(Addr
) selfpc
)
905 /* This function is simply a wrapper around the _dl_mcount function
906 which does not require a FROMPC parameter since this is the
908 extern void _dl_mcount_wrapper (void *selfpc
);
910 /* Show the members of the auxiliary array passed up from the kernel. */
911 extern void _dl_show_auxv (void) internal_function
;
913 /* Return all environment variables starting with `LD_', one after the
915 extern char *_dl_next_ld_env_entry (char ***position
) internal_function
;
917 /* Return an array with the names of the important hardware capabilities. */
918 extern const struct r_strlenpair
*_dl_important_hwcaps (const char *platform
,
921 size_t *max_capstrlen
)
924 /* Look up NAME in ld.so.cache and return the file name stored there,
925 or null if none is found. */
926 extern const char *_dl_load_cache_lookup (const char *name
)
929 /* If the system does not support MAP_COPY we cannot leave the file open
930 all the time since this would create problems when the file is replaced.
931 Therefore we provide this function to close the file and open it again
933 extern void _dl_unload_cache (void) attribute_hidden
;
935 /* System-dependent function to read a file's whole contents in the
936 most convenient manner available. *SIZEP gets the size of the
937 file. On error MAP_FAILED is returned. */
938 extern void *_dl_sysdep_read_whole_file (const char *file
, size_t *sizep
,
940 internal_function attribute_hidden
;
942 /* System-specific function to do initial startup for the dynamic linker.
943 After this, file access calls and getenv must work. This is responsible
944 for setting __libc_enable_secure if we need to be secure (e.g. setuid),
945 and for setting _dl_argc and _dl_argv, and then calling _dl_main. */
946 extern ElfW(Addr
) _dl_sysdep_start (void **start_argptr
,
947 void (*dl_main
) (const ElfW(Phdr
) *phdr
,
949 ElfW(Addr
) *user_entry
,
953 extern void _dl_sysdep_start_cleanup (void)
954 internal_function attribute_hidden
;
957 /* Determine next available module ID. */
958 extern size_t _dl_next_tls_modid (void) internal_function attribute_hidden
;
960 /* Calculate offset of the TLS blocks in the static TLS block. */
961 extern void _dl_determine_tlsoffset (void) internal_function attribute_hidden
;
963 /* Set up the data structures for TLS, when they were not set up at startup.
964 Returns nonzero on malloc failure.
965 This is called from _dl_map_object_from_fd or by libpthread. */
966 extern int _dl_tls_setup (void) internal_function
;
967 rtld_hidden_proto (_dl_tls_setup
)
969 /* Allocate memory for static TLS block (unless MEM is nonzero) and dtv. */
970 extern void *_dl_allocate_tls (void *mem
) internal_function
;
971 rtld_hidden_proto (_dl_allocate_tls
)
973 /* Get size and alignment requirements of the static TLS block. */
974 extern void _dl_get_tls_static_info (size_t *sizep
, size_t *alignp
)
977 extern void _dl_allocate_static_tls (struct link_map
*map
)
978 internal_function attribute_hidden
;
980 /* These are internal entry points to the two halves of _dl_allocate_tls,
981 only used within rtld.c itself at startup time. */
982 extern void *_dl_allocate_tls_storage (void)
983 internal_function attribute_hidden
;
984 extern void *_dl_allocate_tls_init (void *) internal_function
;
985 rtld_hidden_proto (_dl_allocate_tls_init
)
987 /* Deallocate memory allocated with _dl_allocate_tls. */
988 extern void _dl_deallocate_tls (void *tcb
, bool dealloc_tcb
) internal_function
;
989 rtld_hidden_proto (_dl_deallocate_tls
)
991 extern void _dl_nothread_init_static_tls (struct link_map
*) attribute_hidden
;
993 /* Find origin of the executable. */
994 extern const char *_dl_get_origin (void) attribute_hidden
;
997 extern size_t _dl_dst_count (const char *name
, int is_path
) attribute_hidden
;
999 /* Substitute DST values. */
1000 extern char *_dl_dst_substitute (struct link_map
*l
, const char *name
,
1001 char *result
, int is_path
) attribute_hidden
;
1003 /* Check validity of the caller. */
1004 extern int _dl_check_caller (const void *caller
, enum allowmask mask
)
1007 /* Open the shared object NAME, relocate it, and run its initializer if it
1008 hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If
1009 the object is already opened, returns its existing map. */
1010 extern void *_dl_open (const char *name
, int mode
, const void *caller
,
1011 Lmid_t nsid
, int argc
, char *argv
[], char *env
[])
1014 /* Free or queue for freeing scope OLD. If other threads might be
1015 in the middle of _dl_fixup, _dl_profile_fixup or dl*sym using the
1016 old scope, OLD can't be freed until no thread is using it. */
1017 extern int _dl_scope_free (void *) attribute_hidden
;
1019 /* Add module to slot information data. */
1020 extern void _dl_add_to_slotinfo (struct link_map
*l
) attribute_hidden
;
1022 /* Update slot information data for at least the generation of the
1023 module with the given index. */
1024 extern struct link_map
*_dl_update_slotinfo (unsigned long int req_modid
);
1026 /* Look up the module's TLS block as for __tls_get_addr,
1027 but never touch anything. Return null if it's not allocated yet. */
1028 extern void *_dl_tls_get_addr_soft (struct link_map
*l
) attribute_hidden
;
1030 extern int _dl_addr_inside_object (struct link_map
*l
, const ElfW(Addr
) addr
)
1031 internal_function attribute_hidden
;
1033 /* Show show of an object. */
1034 extern void _dl_show_scope (struct link_map
*new, int from
);
1036 extern struct link_map
*_dl_find_dso_for_object (const ElfW(Addr
) addr
)
1038 rtld_hidden_proto (_dl_find_dso_for_object
)
1040 /* Initialization which is normally done by the dynamic linker. */
1041 extern void _dl_non_dynamic_init (void) internal_function
;
1043 /* Used by static binaries to check the auxiliary vector. */
1044 extern void _dl_aux_init (ElfW(auxv_t
) *av
) internal_function
;
1049 #endif /* ldsodefs.h */