1 /* Run-time dynamic linker data structures for loaded ELF shared objects.
2 Copyright (C) 1995-2019 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 <https://www.gnu.org/licenses/>. */
33 #include <fpu_control.h>
36 #include <dl-lookupcfg.h>
37 #include <dl-sysdep.h>
38 #include <libc-lock.h>
39 #include <hp-timing.h>
44 #define VERSYMIDX(sym) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (sym))
45 #define VALIDX(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
46 + DT_EXTRANUM + DT_VALTAGIDX (tag))
47 #define ADDRIDX(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
48 + DT_EXTRANUM + DT_VALNUM + DT_ADDRTAGIDX (tag))
50 /* Type of GNU hash which the machine uses. */
51 #ifndef ELF_MACHINE_GNU_HASH_ADDRIDX
52 # define ELF_MACHINE_GNU_HASH_ADDRIDX ADDRIDX (DT_GNU_HASH)
55 /* Calculate the index of a symbol in GNU hash. */
56 #ifndef ELF_MACHINE_HASH_SYMIDX
57 # define ELF_MACHINE_HASH_SYMIDX(map, hasharr) \
58 ((hasharr) - (map)->l_gnu_chain_zero)
61 /* Setup MIPS xhash. Defined only for MIPS. */
62 #ifndef ELF_MACHINE_XHASH_SETUP
63 # define ELF_MACHINE_XHASH_SETUP(hash32, symbias, map) \
64 ((void) (hash32), (void) (symbias), (void) (map))
67 /* We use this macro to refer to ELF types independent of the native wordsize.
68 `ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'. */
69 #define ELFW(type) _ElfW (ELF, __ELF_NATIVE_CLASS, type)
71 /* All references to the value of l_info[DT_PLTGOT],
72 l_info[DT_STRTAB], l_info[DT_SYMTAB], l_info[DT_RELA],
73 l_info[DT_REL], l_info[DT_JMPREL], and l_info[VERSYMIDX (DT_VERSYM)]
74 have to be accessed via the D_PTR macro. The macro is needed since for
75 most architectures the entry is already relocated - but for some not
76 and we need to relocate at access time. */
77 #ifdef DL_RO_DYN_SECTION
78 # define D_PTR(map, i) ((map)->i->d_un.d_ptr + (map)->l_addr)
80 # define D_PTR(map, i) (map)->i->d_un.d_ptr
83 /* Result of the lookup functions and how to retrieve the base address. */
84 typedef struct link_map
*lookup_t
;
85 #define LOOKUP_VALUE(map) map
86 #define LOOKUP_VALUE_ADDRESS(map, set) ((set) || (map) ? (map)->l_addr : 0)
88 /* Calculate the address of symbol REF using the base address from map MAP,
89 if non-NULL. Don't check for NULL map if MAP_SET is TRUE. */
90 #define SYMBOL_ADDRESS(map, ref, map_set) \
92 : (__glibc_unlikely ((ref)->st_shndx == SHN_ABS) ? 0 \
93 : LOOKUP_VALUE_ADDRESS (map, map_set)) + (ref)->st_value)
95 /* On some architectures a pointer to a function is not just a pointer
96 to the actual code of the function but rather an architecture
97 specific descriptor. */
98 #ifndef ELF_FUNCTION_PTR_IS_SPECIAL
99 # define DL_SYMBOL_ADDRESS(map, ref) \
100 (void *) SYMBOL_ADDRESS (map, ref, false)
101 # define DL_LOOKUP_ADDRESS(addr) ((ElfW(Addr)) (addr))
102 # define DL_CALL_DT_INIT(map, start, argc, argv, env) \
103 ((init_t) (start)) (argc, argv, env)
104 # define DL_CALL_DT_FINI(map, start) ((fini_t) (start)) ()
107 /* On some architectures dladdr can't use st_size of all symbols this way. */
108 #define DL_ADDR_SYM_MATCH(L, SYM, MATCHSYM, ADDR) \
109 ((ADDR) >= (L)->l_addr + (SYM)->st_value \
110 && ((((SYM)->st_shndx == SHN_UNDEF || (SYM)->st_size == 0) \
111 && (ADDR) == (L)->l_addr + (SYM)->st_value) \
112 || (ADDR) < (L)->l_addr + (SYM)->st_value + (SYM)->st_size) \
113 && ((MATCHSYM) == NULL || (MATCHSYM)->st_value < (SYM)->st_value))
115 /* According to the ELF gABI no STV_HIDDEN or STV_INTERNAL symbols are
116 expected to be present in dynamic symbol tables as they should have
117 been either removed or converted to STB_LOCAL binding by the static
118 linker. However some GNU binutils versions produce such symbols in
119 some cases. To prevent such symbols present in a buggy binary from
120 preempting global symbols we filter them out with this predicate. */
121 static __always_inline
bool
122 dl_symbol_visibility_binds_local_p (const ElfW(Sym
) *sym
)
124 return (ELFW(ST_VISIBILITY
) (sym
->st_other
) == STV_HIDDEN
125 || ELFW(ST_VISIBILITY
) (sym
->st_other
) == STV_INTERNAL
);
128 /* Unmap a loaded object, called by _dl_close (). */
129 #ifndef DL_UNMAP_IS_SPECIAL
130 # define DL_UNMAP(map) _dl_unmap_segments (map)
133 /* By default we do not need special support to initialize DSOs loaded
134 by statically linked binaries. */
135 #ifndef DL_STATIC_INIT
136 # define DL_STATIC_INIT(map)
139 /* Reloc type classes as returned by elf_machine_type_class().
140 ELF_RTYPE_CLASS_PLT means this reloc should not be satisfied by
141 some PLT symbol, ELF_RTYPE_CLASS_COPY means this reloc should not be
142 satisfied by any symbol in the executable. Some architectures do
143 not support copy relocations. In this case we define the macro to
144 zero so that the code for handling them gets automatically optimized
145 out. ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA means address of protected
146 data defined in the shared library may be external, i.e., due to copy
148 #define ELF_RTYPE_CLASS_PLT 1
149 #ifndef DL_NO_COPY_RELOCS
150 # define ELF_RTYPE_CLASS_COPY 2
152 # define ELF_RTYPE_CLASS_COPY 0
154 /* If DL_EXTERN_PROTECTED_DATA is defined, address of protected data
155 defined in the shared library may be external, i.e., due to copy
157 #ifdef DL_EXTERN_PROTECTED_DATA
158 # define ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA 4
160 # define ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA 0
163 /* ELF uses the PF_x macros to specify the segment permissions, mmap
164 uses PROT_xxx. In most cases the three macros have the values 1, 2,
165 and 3 but not in a matching order. The following macros allows
166 converting from the PF_x values to PROT_xxx values. */
168 ((PROT_READ << (PF_R * 4)) \
169 | (PROT_WRITE << (PF_W * 4)) \
170 | (PROT_EXEC << (PF_X * 4)) \
171 | ((PROT_READ | PROT_WRITE) << ((PF_R | PF_W) * 4)) \
172 | ((PROT_READ | PROT_EXEC) << ((PF_R | PF_X) * 4)) \
173 | ((PROT_WRITE | PROT_EXEC) << (PF_W | PF_X) * 4) \
174 | ((PROT_READ | PROT_WRITE | PROT_EXEC) << ((PF_R | PF_W | PF_X) * 4)))
176 /* The filename itself, or the main program name, if available. */
177 #define DSO_FILENAME(name) ((name)[0] ? (name) \
178 : (rtld_progname ?: "<main program>"))
180 #define RTLD_PROGNAME (rtld_progname ?: "<program name unknown>")
182 /* For the version handling we need an array with only names and their
184 struct r_found_version
190 const char *filename
;
193 /* We want to cache information about the searches for shared objects. */
195 enum r_dir_status
{ unknown
, nonexisting
, existing
};
197 struct r_search_path_elem
199 /* This link is only used in the `all_dirs' member of `r_search_path'. */
200 struct r_search_path_elem
*next
;
202 /* Strings saying where the definition came from. */
206 /* Basename for this search path element. The string must end with
207 a slash character. */
211 enum r_dir_status status
[0];
221 /* A data structure for a simple single linked list of strings. */
224 const char *name
; /* Name requested (before search). */
225 struct libname_list
*next
; /* Link to next name for this object. */
226 int dont_free
; /* Flag whether this element should be freed
227 if the object is not entirely unloaded. */
231 /* Bit masks for the objects which valid callers can come from to
232 functions with restricted interface. */
237 allow_libpthread
= 4,
244 void (*activity
) (uintptr_t *, unsigned int);
245 char *(*objsearch
) (const char *, uintptr_t *, unsigned int);
246 unsigned int (*objopen
) (struct link_map
*, Lmid_t
, uintptr_t *);
247 void (*preinit
) (uintptr_t *);
250 uintptr_t (*symbind32
) (Elf32_Sym
*, unsigned int, uintptr_t *,
251 uintptr_t *, unsigned int *, const char *);
252 uintptr_t (*symbind64
) (Elf64_Sym
*, unsigned int, uintptr_t *,
253 uintptr_t *, unsigned int *, const char *);
257 #ifdef ARCH_PLTENTER_MEMBERS
258 ARCH_PLTENTER_MEMBERS
;
263 #ifdef ARCH_PLTEXIT_MEMBERS
264 ARCH_PLTEXIT_MEMBERS
;
267 unsigned int (*objclose
) (uintptr_t *);
269 struct audit_ifaces
*next
;
273 /* Test whether given NAME matches any of the names of the given object. */
274 extern int _dl_name_match_p (const char *__name
, const struct link_map
*__map
)
277 /* Compute next higher prime number. */
278 extern unsigned long int _dl_higher_prime_number (unsigned long int n
)
281 /* A stripped down strtoul-like implementation. */
282 uint64_t _dl_strtoul (const char *, char **) attribute_hidden
;
284 /* Function used as argument for `_dl_receive_error' function. The
285 arguments are the error code, error string, and the objname the
286 error occurred in. */
287 typedef void (*receiver_fct
) (int, const char *, const char *);
289 /* Internal functions of the run-time dynamic linker.
290 These can be accessed if you link again the dynamic linker
291 as a shared library, as in `-lld' or `/lib/ld.so' explicitly;
292 but are not normally of interest to user programs.
294 The `-ldl' library functions in <dlfcn.h> provide a simple
295 user interface to run-time dynamic linking. */
299 # define EXTERN extern
300 # define GL(name) _##name
304 # define GL(name) _rtld_local._##name
306 # define GL(name) _rtld_global._##name
311 /* Don't change the order of the following elements. 'dl_loaded'
312 must remain the first element. Forever. */
314 /* Non-shared code has no support for multiple namespaces. */
320 EXTERN
struct link_namespaces
322 /* A pointer to the map for the main map. */
323 struct link_map
*_ns_loaded
;
324 /* Number of object in the _dl_loaded list. */
325 unsigned int _ns_nloaded
;
326 /* Direct pointer to the searchlist of the main object. */
327 struct r_scope_elem
*_ns_main_searchlist
;
328 /* This is zero at program start to signal that the global scope map is
329 allocated by rtld. Later it keeps the size of the map. It might be
330 reset if in _dl_close if the last global object is removed. */
331 size_t _ns_global_scope_alloc
;
332 /* Search table for unique objects. */
333 struct unique_sym_table
335 __rtld_lock_define_recursive (, lock
)
340 const ElfW(Sym
) *sym
;
341 const struct link_map
*map
;
345 void (*free
) (void *);
346 } _ns_unique_sym_table
;
347 /* Keep track of changes to each namespace' list. */
348 struct r_debug _ns_debug
;
350 /* One higher than index of last used namespace. */
351 EXTERN
size_t _dl_nns
;
353 /* During the program run we must not modify the global data of
354 loaded shared object simultanously in two threads. Therefore we
355 protect `_dl_open' and `_dl_close' in dl-close.c.
357 This must be a recursive lock since the initializer function of
358 the loaded object might as well require a call to this function.
359 At this time it is not anymore a problem to modify the tables. */
360 __rtld_lock_define_recursive (EXTERN
, _dl_load_lock
)
361 /* This lock is used to keep __dl_iterate_phdr from inspecting the
362 list of loaded objects while an object is added to or removed
364 __rtld_lock_define_recursive (EXTERN
, _dl_load_write_lock
)
366 /* Incremented whenever something may have been added to dl_loaded. */
367 EXTERN
unsigned long long _dl_load_adds
;
369 /* The object to be initialized first. */
370 EXTERN
struct link_map
*_dl_initfirst
;
372 /* Map of shared object to be profiled. */
373 EXTERN
struct link_map
*_dl_profile_map
;
375 /* Counters for the number of relocations performed. */
376 EXTERN
unsigned long int _dl_num_relocations
;
377 EXTERN
unsigned long int _dl_num_cache_relocations
;
379 /* List of search directories. */
380 EXTERN
struct r_search_path_elem
*_dl_all_dirs
;
382 /* Structure describing the dynamic linker itself. We need to
383 reserve memory for the data the audit libraries need. */
384 EXTERN
struct link_map _dl_rtld_map
;
386 struct auditstate audit_data
[DL_NNS
];
389 #if defined SHARED && defined _LIBC_REENTRANT \
390 && defined __rtld_lock_default_lock_recursive
391 EXTERN
void (*_dl_rtld_lock_recursive
) (void *);
392 EXTERN
void (*_dl_rtld_unlock_recursive
) (void *);
395 /* Get architecture specific definitions. */
396 #define PROCINFO_DECL
397 #ifndef PROCINFO_CLASS
398 # define PROCINFO_CLASS EXTERN
400 #include <dl-procruntime.c>
402 /* If loading a shared object requires that we make the stack executable
403 when it was not, we do it by calling this function.
404 It returns an errno code or zero on success. */
405 EXTERN
int (*_dl_make_stack_executable_hook
) (void **);
407 /* Prevailing state of the stack, PF_X indicating it's executable. */
408 EXTERN
ElfW(Word
) _dl_stack_flags
;
410 /* Flag signalling whether there are gaps in the module ID allocation. */
411 EXTERN
bool _dl_tls_dtv_gaps
;
412 /* Highest dtv index currently needed. */
413 EXTERN
size_t _dl_tls_max_dtv_idx
;
414 /* Information about the dtv slots. */
415 EXTERN
struct dtv_slotinfo_list
418 struct dtv_slotinfo_list
*next
;
422 struct link_map
*map
;
424 } *_dl_tls_dtv_slotinfo_list
;
425 /* Number of modules in the static TLS block. */
426 EXTERN
size_t _dl_tls_static_nelem
;
427 /* Size of the static TLS block. */
428 EXTERN
size_t _dl_tls_static_size
;
429 /* Size actually allocated in the static TLS block. */
430 EXTERN
size_t _dl_tls_static_used
;
431 /* Alignment requirement of the static TLS block. */
432 EXTERN
size_t _dl_tls_static_align
;
434 /* Number of additional entries in the slotinfo array of each slotinfo
435 list element. A large number makes it almost certain take we never
436 have to iterate beyond the first element in the slotinfo list. */
437 #define TLS_SLOTINFO_SURPLUS (62)
439 /* Number of additional slots in the dtv allocated. */
440 #define DTV_SURPLUS (14)
442 /* Initial dtv of the main thread, not allocated with normal malloc. */
443 EXTERN
void *_dl_initial_dtv
;
444 /* Generation counter for the dtv. */
445 EXTERN
size_t _dl_tls_generation
;
447 EXTERN
void (*_dl_init_static_tls
) (struct link_map
*);
449 EXTERN
void (*_dl_wait_lookup_done
) (void);
451 /* Scopes to free after next THREAD_GSCOPE_WAIT (). */
452 EXTERN
struct dl_scope_free_list
456 } *_dl_scope_free_list
;
457 #if !THREAD_GSCOPE_IN_TCB
458 EXTERN
int _dl_thread_gscope_count
;
462 # define __rtld_global_attribute__
464 # ifdef HAVE_SDATA_SECTION
465 # define __rtld_local_attribute__ \
466 __attribute__ ((visibility ("hidden"), section (".sdata")))
467 # undef __rtld_global_attribute__
468 # define __rtld_global_attribute__ __attribute__ ((section (".sdata")))
470 # define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
472 extern struct rtld_global _rtld_local __rtld_local_attribute__
;
473 # undef __rtld_local_attribute__
475 extern struct rtld_global _rtld_global __rtld_global_attribute__
;
476 # undef __rtld_global_attribute__
480 # define GLRO(name) _##name
483 # define GLRO(name) _rtld_local_ro._##name
485 # define GLRO(name) _rtld_global_ro._##name
487 struct rtld_global_ro
491 /* If nonzero the appropriate debug information is printed. */
492 EXTERN
int _dl_debug_mask
;
493 #define DL_DEBUG_LIBS (1 << 0)
494 #define DL_DEBUG_IMPCALLS (1 << 1)
495 #define DL_DEBUG_BINDINGS (1 << 2)
496 #define DL_DEBUG_SYMBOLS (1 << 3)
497 #define DL_DEBUG_VERSIONS (1 << 4)
498 #define DL_DEBUG_RELOC (1 << 5)
499 #define DL_DEBUG_FILES (1 << 6)
500 #define DL_DEBUG_STATISTICS (1 << 7)
501 #define DL_DEBUG_UNUSED (1 << 8)
502 #define DL_DEBUG_SCOPES (1 << 9)
503 /* These two are used only internally. */
504 #define DL_DEBUG_HELP (1 << 10)
505 #define DL_DEBUG_PRELINK (1 << 11)
508 EXTERN
unsigned int _dl_osversion
;
510 EXTERN
const char *_dl_platform
;
511 EXTERN
size_t _dl_platformlen
;
513 /* Cached value of `getpagesize ()'. */
514 EXTERN
size_t _dl_pagesize
;
516 /* Do we read from ld.so.cache? */
517 EXTERN
int _dl_inhibit_cache
;
519 /* Copy of the content of `_dl_main_searchlist' at startup time. */
520 EXTERN
struct r_scope_elem _dl_initial_searchlist
;
522 /* CLK_TCK as reported by the kernel. */
523 EXTERN
int _dl_clktck
;
525 /* If nonzero print warnings messages. */
526 EXTERN
int _dl_verbose
;
528 /* File descriptor to write debug messages to. */
529 EXTERN
int _dl_debug_fd
;
531 /* Do we do lazy relocations? */
534 /* Nonzero if runtime lookups should not update the .got/.plt. */
535 EXTERN
int _dl_bind_not
;
537 /* Nonzero if references should be treated as weak during runtime
539 EXTERN
int _dl_dynamic_weak
;
541 /* Default floating-point control word. */
542 EXTERN fpu_control_t _dl_fpu_control
;
544 /* Expected cache ID. */
545 EXTERN
int _dl_correct_cache_id
;
547 /* Mask for hardware capabilities that are available. */
548 EXTERN
uint64_t _dl_hwcap
;
551 /* Mask for important hardware capabilities we honour. */
552 EXTERN
uint64_t _dl_hwcap_mask
;
555 #ifdef HAVE_AUX_VECTOR
556 /* Pointer to the auxv list supplied to the program at startup. */
557 EXTERN
ElfW(auxv_t
) *_dl_auxv
;
560 /* Get architecture specific definitions. */
561 #include <dl-procinfo.c>
563 /* Names of shared object for which the RPATH should be ignored. */
564 EXTERN
const char *_dl_inhibit_rpath
;
566 /* Location of the binary. */
567 EXTERN
const char *_dl_origin_path
;
569 /* -1 if the dynamic linker should honor library load bias,
570 0 if not, -2 use the default (honor biases for normal
571 binaries, don't honor for PIEs). */
572 EXTERN
ElfW(Addr
) _dl_use_load_bias
;
574 /* Name of the shared object to be profiled (if any). */
575 EXTERN
const char *_dl_profile
;
576 /* Filename of the output file. */
577 EXTERN
const char *_dl_profile_output
;
578 /* Name of the object we want to trace the prelinking. */
579 EXTERN
const char *_dl_trace_prelink
;
580 /* Map of shared object to be prelink traced. */
581 EXTERN
struct link_map
*_dl_trace_prelink_map
;
583 /* All search directories defined at startup. This is assigned a
584 non-NULL pointer by the ld.so startup code (after initialization
585 to NULL), so this can also serve as an indicator whether a copy
586 of ld.so is initialized and active. See the rtld_active function
588 EXTERN
struct r_search_path_elem
*_dl_init_all_dirs
;
590 #ifdef NEED_DL_SYSINFO
591 /* Syscall handling improvements. This is very specific to x86. */
592 EXTERN
uintptr_t _dl_sysinfo
;
595 #ifdef NEED_DL_SYSINFO_DSO
596 /* The vsyscall page is a virtual DSO pre-mapped by the kernel.
597 This points to its ELF header. */
598 EXTERN
const ElfW(Ehdr
) *_dl_sysinfo_dso
;
600 /* At startup time we set up the normal DSO data structure for it,
601 and this points to it. */
602 EXTERN
struct link_map
*_dl_sysinfo_map
;
605 /* Mask for more hardware capabilities that are available on some
607 EXTERN
uint64_t _dl_hwcap2
;
610 /* We add a function table to _rtld_global which is then used to
611 call the function instead of going through the PLT. The result
612 is that we can avoid exporting the functions and we do not jump
613 PLT relocations in libc.so. */
614 void (*_dl_debug_printf
) (const char *, ...)
615 __attribute__ ((__format__ (__printf__
, 1, 2)));
616 void (*_dl_mcount
) (ElfW(Addr
) frompc
, ElfW(Addr
) selfpc
);
617 lookup_t (*_dl_lookup_symbol_x
) (const char *, struct link_map
*,
618 const ElfW(Sym
) **, struct r_scope_elem
*[],
619 const struct r_found_version
*, int, int,
621 void *(*_dl_open
) (const char *file
, int mode
, const void *caller_dlopen
,
622 Lmid_t nsid
, int argc
, char *argv
[], char *env
[]);
623 void (*_dl_close
) (void *map
);
624 void *(*_dl_tls_get_addr_soft
) (struct link_map
*);
625 #ifdef HAVE_DL_DISCOVER_OSVERSION
626 int (*_dl_discover_osversion
) (void);
629 /* List of auditing interfaces. */
630 struct audit_ifaces
*_dl_audit
;
631 unsigned int _dl_naudit
;
633 # define __rtld_global_attribute__
635 # define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
636 extern struct rtld_global_ro _rtld_local_ro
637 attribute_relro __rtld_local_attribute__
;
638 extern struct rtld_global_ro _rtld_global_ro
639 attribute_relro __rtld_global_attribute__
;
640 # undef __rtld_local_attribute__
642 /* We cheat a bit here. We declare the variable as as const even
643 though it is at startup. */
644 extern const struct rtld_global_ro _rtld_global_ro
645 attribute_relro __rtld_global_attribute__
;
647 # undef __rtld_global_attribute__
652 /* dl-support.c defines these and initializes them early on. */
653 extern const ElfW(Phdr
) *_dl_phdr
;
654 extern size_t _dl_phnum
;
657 /* This is the initial value of GL(dl_make_stack_executable_hook).
658 A threads library can change it. */
659 extern int _dl_make_stack_executable (void **stack_endp
);
660 rtld_hidden_proto (_dl_make_stack_executable
)
662 /* Variable pointing to the end of the stack (or close to it). This value
663 must be constant over the runtime of the application. Some programs
664 might use the variable which results in copy relocations on some
665 platforms. But this does not matter, ld.so can always use the local
667 extern void *__libc_stack_end
668 #ifndef LIBC_STACK_END_NOT_RELRO
672 rtld_hidden_proto (__libc_stack_end
)
674 /* Parameters passed to the dynamic linker. */
675 extern int _dl_argc attribute_hidden attribute_relro
;
676 extern char **_dl_argv
677 #ifndef DL_ARGV_NOT_RELRO
681 rtld_hidden_proto (_dl_argv
)
683 extern unsigned int _dl_skip_args attribute_hidden
684 # ifndef DL_ARGV_NOT_RELRO
688 extern unsigned int _dl_skip_args_internal attribute_hidden
689 # ifndef DL_ARGV_NOT_RELRO
694 #define rtld_progname _dl_argv[0]
696 /* Flag set at startup and cleared when the last initializer has run. */
697 extern int _dl_starting_up
;
698 weak_extern (_dl_starting_up
)
699 rtld_hidden_proto (_dl_starting_up
)
701 /* Random data provided by the kernel. */
702 extern void *_dl_random attribute_hidden attribute_relro
;
704 /* Write message on the debug file descriptor. The parameters are
705 interpreted as for a `printf' call. All the lines start with a
706 tag showing the PID. */
707 extern void _dl_debug_printf (const char *fmt
, ...)
708 __attribute__ ((__format__ (__printf__
, 1, 2))) attribute_hidden
;
710 /* Write message on the debug file descriptor. The parameters are
711 interpreted as for a `printf' call. All the lines buf the first
712 start with a tag showing the PID. */
713 extern void _dl_debug_printf_c (const char *fmt
, ...)
714 __attribute__ ((__format__ (__printf__
, 1, 2))) attribute_hidden
;
717 /* Write a message on the specified descriptor FD. The parameters are
718 interpreted as for a `printf' call. */
719 #if IS_IN (rtld) || !defined (SHARED)
720 extern void _dl_dprintf (int fd
, const char *fmt
, ...)
721 __attribute__ ((__format__ (__printf__
, 2, 3)))
724 __attribute__ ((always_inline
, __format__ (__printf__
, 2, 3)))
726 _dl_dprintf (int fd
, const char *fmt
, ...)
728 /* Use local declaration to avoid includign <stdio.h>. */
729 extern int __dprintf(int fd
, const char *format
, ...) attribute_hidden
;
730 __dprintf (fd
, fmt
, __builtin_va_arg_pack ());
734 /* Write a message on the specified descriptor standard output. The
735 parameters are interpreted as for a `printf' call. */
736 #define _dl_printf(fmt, args...) \
737 _dl_dprintf (STDOUT_FILENO, fmt, ##args)
739 /* Write a message on the specified descriptor standard error. The
740 parameters are interpreted as for a `printf' call. */
741 #define _dl_error_printf(fmt, args...) \
742 _dl_dprintf (STDERR_FILENO, fmt, ##args)
744 /* Write a message on the specified descriptor standard error and exit
745 the program. The parameters are interpreted as for a `printf' call. */
746 #define _dl_fatal_printf(fmt, args...) \
749 _dl_dprintf (STDERR_FILENO, fmt, ##args); \
755 /* An exception raised by the _dl_signal_error function family and
756 caught by _dl_catch_error function family. Exceptions themselves
757 are copied as part of the raise operation, but the strings are
762 const char *errstring
;
764 /* This buffer typically stores both objname and errstring
766 char *message_buffer
;
769 /* Creates a new exception. This calls malloc; if allocation fails,
770 dummy values are inserted. OBJECT is the name of the problematical
771 shared object, or null if its a general problem. ERRSTRING is a
772 string describing the specific problem. */
773 void _dl_exception_create (struct dl_exception
*, const char *object
,
774 const char *errstring
)
775 __attribute__ ((nonnull (1, 3)));
776 rtld_hidden_proto (_dl_exception_create
)
778 /* Like _dl_exception_create, but create errstring from a format
779 string FMT. Currently, only "%s" and "%%" are supported as format
781 void _dl_exception_create_format (struct dl_exception
*, const char *objname
,
782 const char *fmt
, ...)
783 __attribute__ ((nonnull (1, 3), format (printf
, 3, 4)));
784 rtld_hidden_proto (_dl_exception_create_format
)
786 /* Deallocate the exception, freeing allocated buffers (if
788 void _dl_exception_free (struct dl_exception
*)
789 __attribute__ ((nonnull (1)));
790 rtld_hidden_proto (_dl_exception_free
)
792 /* This function is called by all the internal dynamic linker
793 functions when they encounter an error. ERRCODE is either an
794 `errno' code or zero; it specifies the return value of
795 _dl_catch_error. OCCASION is included in the error message if the
796 process is terminated immediately. */
797 void _dl_signal_exception (int errcode
, struct dl_exception
*,
798 const char *occasion
)
799 __attribute__ ((__noreturn__
));
800 libc_hidden_proto (_dl_signal_exception
)
802 /* Like _dl_signal_exception, but creates the exception first. */
803 extern void _dl_signal_error (int errcode
, const char *object
,
804 const char *occasion
, const char *errstring
)
805 __attribute__ ((__noreturn__
));
806 libc_hidden_proto (_dl_signal_error
)
808 /* Like _dl_signal_exception, but may return when called in the
809 context of _dl_receive_error. This is only used during ld.so
810 bootstrap. In static and profiled builds, this is equivalent to
811 _dl_signal_exception. */
813 extern void _dl_signal_cexception (int errcode
, struct dl_exception
*,
814 const char *occasion
) attribute_hidden
;
816 __attribute__ ((always_inline
))
818 _dl_signal_cexception (int errcode
, struct dl_exception
*exception
,
819 const char *occasion
)
821 _dl_signal_exception (errcode
, exception
, occasion
);
825 /* See _dl_signal_cexception above. */
827 extern void _dl_signal_cerror (int errcode
, const char *object
,
828 const char *occasion
, const char *errstring
)
831 __attribute__ ((always_inline
))
833 _dl_signal_cerror (int errcode
, const char *object
,
834 const char *occasion
, const char *errstring
)
836 _dl_signal_error (errcode
, object
, occasion
, errstring
);
840 /* Call OPERATE, receiving errors from `dl_signal_cerror'. Unlike
841 `_dl_catch_error' the operation is resumed after the OPERATE
843 ARGS is passed as argument to OPERATE. */
844 extern void _dl_receive_error (receiver_fct fct
, void (*operate
) (void *),
845 void *args
) attribute_hidden
;
847 /* Call OPERATE, catching errors from `_dl_signal_error' and related
848 functions. If there is no error, *ERRSTRING is set to null. If
849 there is an error, *ERRSTRING is set to a string constructed from
850 the strings passed to _dl_signal_error, and the error code passed
851 is the return value and *OBJNAME is set to the object name which
852 experienced the problems. ERRSTRING if nonzero points to a
853 malloc'ed string which the caller has to free after use. ARGS is
854 passed as argument to OPERATE. MALLOCEDP is set to true only if
855 the returned string is allocated using the libc's malloc. */
856 extern int _dl_catch_error (const char **objname
, const char **errstring
,
857 bool *mallocedp
, void (*operate
) (void *),
859 libc_hidden_proto (_dl_catch_error
)
861 /* Call OPERATE (ARGS). If no error occurs, set *EXCEPTION to zero.
862 Otherwise, store a copy of the raised exception in *EXCEPTION,
863 which has to be freed by _dl_exception_free. */
864 int _dl_catch_exception (struct dl_exception
*exception
,
865 void (*operate
) (void *), void *args
);
866 libc_hidden_proto (_dl_catch_exception
)
868 /* Open the shared object NAME and map in its segments.
869 LOADER's DT_RPATH is used in searching for NAME.
870 If the object is already opened, returns its existing map. */
871 extern struct link_map
*_dl_map_object (struct link_map
*loader
,
873 int type
, int trace_mode
, int mode
,
874 Lmid_t nsid
) attribute_hidden
;
876 /* Call _dl_map_object on the dependencies of MAP, and set up
877 MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously
878 loaded objects that will be inserted into MAP->l_searchlist after MAP
879 but before its dependencies. */
880 extern void _dl_map_object_deps (struct link_map
*map
,
881 struct link_map
**preloads
,
882 unsigned int npreloads
, int trace_mode
,
886 /* Cache the locations of MAP's hash table. */
887 extern void _dl_setup_hash (struct link_map
*map
) attribute_hidden
;
890 /* Collect the directories in the search path for LOADER's dependencies.
891 The data structure is defined in <dlfcn.h>. If COUNTING is true,
892 SI->dls_cnt and SI->dls_size are set; if false, those must be as set
893 by a previous call with COUNTING set, and SI must point to SI->dls_size
894 bytes to be used in filling in the result. */
895 extern void _dl_rtld_di_serinfo (struct link_map
*loader
,
896 Dl_serinfo
*si
, bool counting
);
899 /* Search loaded objects' symbol tables for a definition of the symbol
900 referred to by UNDEF. *SYM is the symbol table entry containing the
901 reference; it is replaced with the defining symbol, and the base load
902 address of the defining object is returned. SYMBOL_SCOPE is a
903 null-terminated list of object scopes to search; each object's
904 l_searchlist (i.e. the segment of the dependency tree starting at that
905 object) is searched in turn. REFERENCE_NAME should name the object
906 containing the reference; it is used in error messages.
907 TYPE_CLASS describes the type of symbol we are looking for. */
910 /* If necessary add dependency between user and provider object. */
911 DL_LOOKUP_ADD_DEPENDENCY
= 1,
912 /* Return most recent version instead of default version for
913 unversioned lookup. */
914 DL_LOOKUP_RETURN_NEWEST
= 2,
915 /* Set if dl_lookup* called with GSCOPE lock held. */
916 DL_LOOKUP_GSCOPE_LOCK
= 4,
919 /* Lookup versioned symbol. */
920 extern lookup_t
_dl_lookup_symbol_x (const char *undef
,
921 struct link_map
*undef_map
,
922 const ElfW(Sym
) **sym
,
923 struct r_scope_elem
*symbol_scope
[],
924 const struct r_found_version
*version
,
925 int type_class
, int flags
,
926 struct link_map
*skip_map
)
930 /* Add the new link_map NEW to the end of the namespace list. */
931 extern void _dl_add_to_namespace_list (struct link_map
*new, Lmid_t nsid
)
934 /* Allocate a `struct link_map' for a new object being loaded. */
935 extern struct link_map
*_dl_new_object (char *realname
, const char *libname
,
936 int type
, struct link_map
*loader
,
937 int mode
, Lmid_t nsid
)
940 /* Relocate the given object (if it hasn't already been).
941 SCOPE is passed to _dl_lookup_symbol in symbol lookups.
942 If RTLD_LAZY is set in RELOC-MODE, don't relocate its PLT. */
943 extern void _dl_relocate_object (struct link_map
*map
,
944 struct r_scope_elem
*scope
[],
945 int reloc_mode
, int consider_profiling
)
948 /* Protect PT_GNU_RELRO area. */
949 extern void _dl_protect_relro (struct link_map
*map
) attribute_hidden
;
951 /* Call _dl_signal_error with a message about an unhandled reloc type.
952 TYPE is the result of ELFW(R_TYPE) (r_info), i.e. an R_<CPU>_* value.
953 PLT is nonzero if this was a PLT reloc; it just affects the message. */
954 extern void _dl_reloc_bad_type (struct link_map
*map
,
955 unsigned int type
, int plt
)
956 attribute_hidden
__attribute__ ((__noreturn__
));
958 /* Resolve conflicts if prelinking. */
959 extern void _dl_resolve_conflicts (struct link_map
*l
,
960 ElfW(Rela
) *conflict
,
961 ElfW(Rela
) *conflictend
)
964 /* Check the version dependencies of all objects available through
965 MAP. If VERBOSE print some more diagnostics. */
966 extern int _dl_check_all_versions (struct link_map
*map
, int verbose
,
967 int trace_mode
) attribute_hidden
;
969 /* Check the version dependencies for MAP. If VERBOSE print some more
971 extern int _dl_check_map_versions (struct link_map
*map
, int verbose
,
972 int trace_mode
) attribute_hidden
;
974 /* Initialize the object in SCOPE by calling the constructors with
975 ARGC, ARGV, and ENV as the parameters. */
976 extern void _dl_init (struct link_map
*main_map
, int argc
, char **argv
,
977 char **env
) attribute_hidden
;
979 /* Call the finalizer functions of all shared objects whose
980 initializer functions have completed. */
981 extern void _dl_fini (void) attribute_hidden
;
983 /* Sort array MAPS according to dependencies of the contained objects. */
984 extern void _dl_sort_maps (struct link_map
**maps
, unsigned int nmaps
,
985 char *used
, bool for_fini
) attribute_hidden
;
987 /* The dynamic linker calls this function before and having changing
988 any shared object mappings. The `r_state' member of `struct r_debug'
989 says what change is taking place. This function's address is
990 the value of the `r_brk' member. */
991 extern void _dl_debug_state (void);
992 rtld_hidden_proto (_dl_debug_state
)
994 /* Initialize `struct r_debug' if it has not already been done. The
995 argument is the run-time load address of the dynamic linker, to be put
996 in the `r_ldbase' member. Returns the address of the structure. */
997 extern struct r_debug
*_dl_debug_initialize (ElfW(Addr
) ldbase
, Lmid_t ns
)
1000 /* Initialize the basic data structure for the search paths. */
1001 extern void _dl_init_paths (const char *library_path
) attribute_hidden
;
1003 /* Gather the information needed to install the profiling tables and start
1005 extern void _dl_start_profile (void) attribute_hidden
;
1007 /* The actual functions used to keep book on the calls. */
1008 extern void _dl_mcount (ElfW(Addr
) frompc
, ElfW(Addr
) selfpc
);
1009 rtld_hidden_proto (_dl_mcount
)
1011 /* This function is simply a wrapper around the _dl_mcount function
1012 which does not require a FROMPC parameter since this is the
1013 calling function. */
1014 extern void _dl_mcount_wrapper (void *selfpc
);
1016 /* Show the members of the auxiliary array passed up from the kernel. */
1017 extern void _dl_show_auxv (void) attribute_hidden
;
1019 /* Return all environment variables starting with `LD_', one after the
1021 extern char *_dl_next_ld_env_entry (char ***position
) attribute_hidden
;
1023 /* Return an array with the names of the important hardware capabilities. */
1024 extern const struct r_strlenpair
*_dl_important_hwcaps (const char *platform
,
1025 size_t paltform_len
,
1027 size_t *max_capstrlen
)
1030 /* Look up NAME in ld.so.cache and return the file name stored there,
1031 or null if none is found. Caller must free returned string. */
1032 extern char *_dl_load_cache_lookup (const char *name
) attribute_hidden
;
1034 /* If the system does not support MAP_COPY we cannot leave the file open
1035 all the time since this would create problems when the file is replaced.
1036 Therefore we provide this function to close the file and open it again
1038 extern void _dl_unload_cache (void) attribute_hidden
;
1040 /* System-dependent function to read a file's whole contents in the
1041 most convenient manner available. *SIZEP gets the size of the
1042 file. On error MAP_FAILED is returned. */
1043 extern void *_dl_sysdep_read_whole_file (const char *file
, size_t *sizep
,
1044 int prot
) attribute_hidden
;
1046 /* System-specific function to do initial startup for the dynamic linker.
1047 After this, file access calls and getenv must work. This is responsible
1048 for setting __libc_enable_secure if we need to be secure (e.g. setuid),
1049 and for setting _dl_argc and _dl_argv, and then calling _dl_main. */
1050 extern ElfW(Addr
) _dl_sysdep_start (void **start_argptr
,
1051 void (*dl_main
) (const ElfW(Phdr
) *phdr
,
1053 ElfW(Addr
) *user_entry
,
1054 ElfW(auxv_t
) *auxv
))
1057 extern void _dl_sysdep_start_cleanup (void) attribute_hidden
;
1060 /* Determine next available module ID. */
1061 extern size_t _dl_next_tls_modid (void) attribute_hidden
;
1063 /* Count the modules with TLS segments. */
1064 extern size_t _dl_count_modids (void) attribute_hidden
;
1066 /* Calculate offset of the TLS blocks in the static TLS block. */
1067 extern void _dl_determine_tlsoffset (void) attribute_hidden
;
1070 /* Set up the TCB for statically linked applications. This is called
1071 early during startup because we always use TLS (for errno and the
1072 stack protector, among other things). */
1073 void __libc_setup_tls (void);
1075 # if ENABLE_STATIC_PIE
1076 /* Relocate static executable with PIE. */
1077 extern void _dl_relocate_static_pie (void) attribute_hidden
;
1079 /* Get a pointer to _dl_main_map. */
1080 extern struct link_map
* _dl_get_dl_main_map (void)
1081 __attribute__ ((visibility ("hidden")));
1083 # define _dl_relocate_static_pie()
1087 /* Initialization of libpthread for statically linked applications.
1088 If libpthread is not linked in, this is an empty function. */
1089 void __pthread_initialize_minimal (void) weak_function
;
1091 /* Allocate memory for static TLS block (unless MEM is nonzero) and dtv. */
1092 extern void *_dl_allocate_tls (void *mem
);
1093 rtld_hidden_proto (_dl_allocate_tls
)
1095 /* Get size and alignment requirements of the static TLS block. */
1096 extern void _dl_get_tls_static_info (size_t *sizep
, size_t *alignp
);
1098 extern void _dl_allocate_static_tls (struct link_map
*map
) attribute_hidden
;
1100 /* These are internal entry points to the two halves of _dl_allocate_tls,
1101 only used within rtld.c itself at startup time. */
1102 extern void *_dl_allocate_tls_storage (void) attribute_hidden
;
1103 extern void *_dl_allocate_tls_init (void *);
1104 rtld_hidden_proto (_dl_allocate_tls_init
)
1106 /* Deallocate memory allocated with _dl_allocate_tls. */
1107 extern void _dl_deallocate_tls (void *tcb
, bool dealloc_tcb
);
1108 rtld_hidden_proto (_dl_deallocate_tls
)
1110 extern void _dl_nothread_init_static_tls (struct link_map
*) attribute_hidden
;
1112 /* Find origin of the executable. */
1113 extern const char *_dl_get_origin (void) attribute_hidden
;
1116 extern size_t _dl_dst_count (const char *name
) attribute_hidden
;
1118 /* Substitute DST values. */
1119 extern char *_dl_dst_substitute (struct link_map
*l
, const char *name
,
1120 char *result
) attribute_hidden
;
1122 /* Open the shared object NAME, relocate it, and run its initializer if it
1123 hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If
1124 the object is already opened, returns its existing map. */
1125 extern void *_dl_open (const char *name
, int mode
, const void *caller
,
1126 Lmid_t nsid
, int argc
, char *argv
[], char *env
[])
1129 /* Free or queue for freeing scope OLD. If other threads might be
1130 in the middle of _dl_fixup, _dl_profile_fixup or dl*sym using the
1131 old scope, OLD can't be freed until no thread is using it. */
1132 extern int _dl_scope_free (void *) attribute_hidden
;
1134 /* Add module to slot information data. */
1135 extern void _dl_add_to_slotinfo (struct link_map
*l
) attribute_hidden
;
1137 /* Update slot information data for at least the generation of the
1138 module with the given index. */
1139 extern struct link_map
*_dl_update_slotinfo (unsigned long int req_modid
)
1142 /* Look up the module's TLS block as for __tls_get_addr,
1143 but never touch anything. Return null if it's not allocated yet. */
1144 extern void *_dl_tls_get_addr_soft (struct link_map
*l
) attribute_hidden
;
1146 extern int _dl_addr_inside_object (struct link_map
*l
, const ElfW(Addr
) addr
)
1149 /* Show show of an object. */
1150 extern void _dl_show_scope (struct link_map
*new, int from
)
1153 extern struct link_map
*_dl_find_dso_for_object (const ElfW(Addr
) addr
);
1154 rtld_hidden_proto (_dl_find_dso_for_object
)
1156 /* Initialization which is normally done by the dynamic linker. */
1157 extern void _dl_non_dynamic_init (void)
1160 /* Used by static binaries to check the auxiliary vector. */
1161 extern void _dl_aux_init (ElfW(auxv_t
) *av
)
1164 /* Return true if the ld.so copy in this namespace is actually active
1165 and working. If false, the dl_open/dlfcn hooks have to be used to
1166 call into the outer dynamic linker (which happens after static
1172 /* The default-initialized variable does not have a non-zero
1173 dl_init_all_dirs member, so this allows us to recognize an
1174 initialized and active ld.so copy. */
1175 return GLRO(dl_init_all_dirs
) != NULL
;
1178 static inline struct auditstate
*
1179 link_map_audit_state (struct link_map
*l
, size_t index
)
1181 return &l
->l_audit
[index
];
1187 #endif /* ldsodefs.h */