1 /* Run-time dynamic linker data structures for loaded ELF shared objects.
2 Copyright (C) 1995-2018 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 <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 /* We use this macro to refer to ELF types independent of the native wordsize.
51 `ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'. */
52 #define ELFW(type) _ElfW (ELF, __ELF_NATIVE_CLASS, type)
54 /* All references to the value of l_info[DT_PLTGOT],
55 l_info[DT_STRTAB], l_info[DT_SYMTAB], l_info[DT_RELA],
56 l_info[DT_REL], l_info[DT_JMPREL], and l_info[VERSYMIDX (DT_VERSYM)]
57 have to be accessed via the D_PTR macro. The macro is needed since for
58 most architectures the entry is already relocated - but for some not
59 and we need to relocate at access time. */
60 #ifdef DL_RO_DYN_SECTION
61 # define D_PTR(map, i) ((map)->i->d_un.d_ptr + (map)->l_addr)
63 # define D_PTR(map, i) (map)->i->d_un.d_ptr
66 /* Result of the lookup functions and how to retrieve the base address. */
67 typedef struct link_map
*lookup_t
;
68 #define LOOKUP_VALUE(map) map
69 #define LOOKUP_VALUE_ADDRESS(map) ((map) ? (map)->l_addr : 0)
71 /* On some architectures a pointer to a function is not just a pointer
72 to the actual code of the function but rather an architecture
73 specific descriptor. */
74 #ifndef ELF_FUNCTION_PTR_IS_SPECIAL
75 # define DL_SYMBOL_ADDRESS(map, ref) \
76 (void *) (LOOKUP_VALUE_ADDRESS (map) + ref->st_value)
77 # define DL_LOOKUP_ADDRESS(addr) ((ElfW(Addr)) (addr))
78 # define DL_CALL_DT_INIT(map, start, argc, argv, env) \
79 ((init_t) (start)) (argc, argv, env)
80 # define DL_CALL_DT_FINI(map, start) ((fini_t) (start)) ()
83 /* On some architectures dladdr can't use st_size of all symbols this way. */
84 #define DL_ADDR_SYM_MATCH(L, SYM, MATCHSYM, ADDR) \
85 ((ADDR) >= (L)->l_addr + (SYM)->st_value \
86 && ((((SYM)->st_shndx == SHN_UNDEF || (SYM)->st_size == 0) \
87 && (ADDR) == (L)->l_addr + (SYM)->st_value) \
88 || (ADDR) < (L)->l_addr + (SYM)->st_value + (SYM)->st_size) \
89 && ((MATCHSYM) == NULL || (MATCHSYM)->st_value < (SYM)->st_value))
91 /* According to the ELF gABI no STV_HIDDEN or STV_INTERNAL symbols are
92 expected to be present in dynamic symbol tables as they should have
93 been either removed or converted to STB_LOCAL binding by the static
94 linker. However some GNU binutils versions produce such symbols in
95 some cases. To prevent such symbols present in a buggy binary from
96 preempting global symbols we filter them out with this predicate. */
97 static __always_inline
bool
98 dl_symbol_visibility_binds_local_p (const ElfW(Sym
) *sym
)
100 return (ELFW(ST_VISIBILITY
) (sym
->st_other
) == STV_HIDDEN
101 || ELFW(ST_VISIBILITY
) (sym
->st_other
) == STV_INTERNAL
);
104 /* Unmap a loaded object, called by _dl_close (). */
105 #ifndef DL_UNMAP_IS_SPECIAL
106 # define DL_UNMAP(map) _dl_unmap_segments (map)
109 /* By default we do not need special support to initialize DSOs loaded
110 by statically linked binaries. */
111 #ifndef DL_STATIC_INIT
112 # define DL_STATIC_INIT(map)
115 /* Reloc type classes as returned by elf_machine_type_class().
116 ELF_RTYPE_CLASS_PLT means this reloc should not be satisfied by
117 some PLT symbol, ELF_RTYPE_CLASS_COPY means this reloc should not be
118 satisfied by any symbol in the executable. Some architectures do
119 not support copy relocations. In this case we define the macro to
120 zero so that the code for handling them gets automatically optimized
121 out. ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA means address of protected
122 data defined in the shared library may be external, i.e., due to copy
124 #define ELF_RTYPE_CLASS_PLT 1
125 #ifndef DL_NO_COPY_RELOCS
126 # define ELF_RTYPE_CLASS_COPY 2
128 # define ELF_RTYPE_CLASS_COPY 0
130 /* If DL_EXTERN_PROTECTED_DATA is defined, address of protected data
131 defined in the shared library may be external, i.e., due to copy
133 #ifdef DL_EXTERN_PROTECTED_DATA
134 # define ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA 4
136 # define ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA 0
139 /* ELF uses the PF_x macros to specify the segment permissions, mmap
140 uses PROT_xxx. In most cases the three macros have the values 1, 2,
141 and 3 but not in a matching order. The following macros allows
142 converting from the PF_x values to PROT_xxx values. */
144 ((PROT_READ << (PF_R * 4)) \
145 | (PROT_WRITE << (PF_W * 4)) \
146 | (PROT_EXEC << (PF_X * 4)) \
147 | ((PROT_READ | PROT_WRITE) << ((PF_R | PF_W) * 4)) \
148 | ((PROT_READ | PROT_EXEC) << ((PF_R | PF_X) * 4)) \
149 | ((PROT_WRITE | PROT_EXEC) << (PF_W | PF_X) * 4) \
150 | ((PROT_READ | PROT_WRITE | PROT_EXEC) << ((PF_R | PF_W | PF_X) * 4)))
152 /* The filename itself, or the main program name, if available. */
153 #define DSO_FILENAME(name) ((name)[0] ? (name) \
154 : (rtld_progname ?: "<main program>"))
156 #define RTLD_PROGNAME (rtld_progname ?: "<program name unknown>")
158 /* For the version handling we need an array with only names and their
160 struct r_found_version
166 const char *filename
;
169 /* We want to cache information about the searches for shared objects. */
171 enum r_dir_status
{ unknown
, nonexisting
, existing
};
173 struct r_search_path_elem
175 /* This link is only used in the `all_dirs' member of `r_search_path'. */
176 struct r_search_path_elem
*next
;
178 /* Strings saying where the definition came from. */
182 /* Basename for this search path element. The string must end with
183 a slash character. */
187 enum r_dir_status status
[0];
197 /* A data structure for a simple single linked list of strings. */
200 const char *name
; /* Name requested (before search). */
201 struct libname_list
*next
; /* Link to next name for this object. */
202 int dont_free
; /* Flag whether this element should be freed
203 if the object is not entirely unloaded. */
207 /* Bit masks for the objects which valid callers can come from to
208 functions with restricted interface. */
213 allow_libpthread
= 4,
220 void (*activity
) (uintptr_t *, unsigned int);
221 char *(*objsearch
) (const char *, uintptr_t *, unsigned int);
222 unsigned int (*objopen
) (struct link_map
*, Lmid_t
, uintptr_t *);
223 void (*preinit
) (uintptr_t *);
226 uintptr_t (*symbind32
) (Elf32_Sym
*, unsigned int, uintptr_t *,
227 uintptr_t *, unsigned int *, const char *);
228 uintptr_t (*symbind64
) (Elf64_Sym
*, unsigned int, uintptr_t *,
229 uintptr_t *, unsigned int *, const char *);
233 #ifdef ARCH_PLTENTER_MEMBERS
234 ARCH_PLTENTER_MEMBERS
;
239 #ifdef ARCH_PLTEXIT_MEMBERS
240 ARCH_PLTEXIT_MEMBERS
;
243 unsigned int (*objclose
) (uintptr_t *);
245 struct audit_ifaces
*next
;
249 /* Test whether given NAME matches any of the names of the given object. */
250 extern int _dl_name_match_p (const char *__name
, const struct link_map
*__map
)
253 /* Compute next higher prime number. */
254 extern unsigned long int _dl_higher_prime_number (unsigned long int n
)
257 /* A stripped down strtoul-like implementation. */
258 uint64_t _dl_strtoul (const char *, char **) attribute_hidden
;
260 /* Function used as argument for `_dl_receive_error' function. The
261 arguments are the error code, error string, and the objname the
262 error occurred in. */
263 typedef void (*receiver_fct
) (int, const char *, const char *);
265 /* Internal functions of the run-time dynamic linker.
266 These can be accessed if you link again the dynamic linker
267 as a shared library, as in `-lld' or `/lib/ld.so' explicitly;
268 but are not normally of interest to user programs.
270 The `-ldl' library functions in <dlfcn.h> provide a simple
271 user interface to run-time dynamic linking. */
275 # define EXTERN extern
276 # define GL(name) _##name
280 # define GL(name) _rtld_local._##name
282 # define GL(name) _rtld_global._##name
287 /* Don't change the order of the following elements. 'dl_loaded'
288 must remain the first element. Forever. */
290 /* Non-shared code has no support for multiple namespaces. */
296 EXTERN
struct link_namespaces
298 /* A pointer to the map for the main map. */
299 struct link_map
*_ns_loaded
;
300 /* Number of object in the _dl_loaded list. */
301 unsigned int _ns_nloaded
;
302 /* Direct pointer to the searchlist of the main object. */
303 struct r_scope_elem
*_ns_main_searchlist
;
304 /* This is zero at program start to signal that the global scope map is
305 allocated by rtld. Later it keeps the size of the map. It might be
306 reset if in _dl_close if the last global object is removed. */
307 size_t _ns_global_scope_alloc
;
308 /* Search table for unique objects. */
309 struct unique_sym_table
311 __rtld_lock_define_recursive (, lock
)
316 const ElfW(Sym
) *sym
;
317 const struct link_map
*map
;
321 void (*free
) (void *);
322 } _ns_unique_sym_table
;
323 /* Keep track of changes to each namespace' list. */
324 struct r_debug _ns_debug
;
326 /* One higher than index of last used namespace. */
327 EXTERN
size_t _dl_nns
;
329 /* During the program run we must not modify the global data of
330 loaded shared object simultanously in two threads. Therefore we
331 protect `_dl_open' and `_dl_close' in dl-close.c.
333 This must be a recursive lock since the initializer function of
334 the loaded object might as well require a call to this function.
335 At this time it is not anymore a problem to modify the tables. */
336 __rtld_lock_define_recursive (EXTERN
, _dl_load_lock
)
337 /* This lock is used to keep __dl_iterate_phdr from inspecting the
338 list of loaded objects while an object is added to or removed
340 __rtld_lock_define_recursive (EXTERN
, _dl_load_write_lock
)
342 /* Incremented whenever something may have been added to dl_loaded. */
343 EXTERN
unsigned long long _dl_load_adds
;
345 /* The object to be initialized first. */
346 EXTERN
struct link_map
*_dl_initfirst
;
348 #if HP_SMALL_TIMING_AVAIL
349 /* Start time on CPU clock. */
350 EXTERN hp_timing_t _dl_cpuclock_offset
;
353 /* Map of shared object to be profiled. */
354 EXTERN
struct link_map
*_dl_profile_map
;
356 /* Counters for the number of relocations performed. */
357 EXTERN
unsigned long int _dl_num_relocations
;
358 EXTERN
unsigned long int _dl_num_cache_relocations
;
360 /* List of search directories. */
361 EXTERN
struct r_search_path_elem
*_dl_all_dirs
;
363 /* Structure describing the dynamic linker itself. We need to
364 reserve memory for the data the audit libraries need. */
365 EXTERN
struct link_map _dl_rtld_map
;
367 struct auditstate audit_data
[DL_NNS
];
370 #if defined SHARED && defined _LIBC_REENTRANT \
371 && defined __rtld_lock_default_lock_recursive
372 EXTERN
void (*_dl_rtld_lock_recursive
) (void *);
373 EXTERN
void (*_dl_rtld_unlock_recursive
) (void *);
376 /* Get architecture specific definitions. */
377 #define PROCINFO_DECL
378 #ifndef PROCINFO_CLASS
379 # define PROCINFO_CLASS EXTERN
381 #include <dl-procruntime.c>
383 /* If loading a shared object requires that we make the stack executable
384 when it was not, we do it by calling this function.
385 It returns an errno code or zero on success. */
386 EXTERN
int (*_dl_make_stack_executable_hook
) (void **);
388 /* Prevailing state of the stack, PF_X indicating it's executable. */
389 EXTERN
ElfW(Word
) _dl_stack_flags
;
391 /* Flag signalling whether there are gaps in the module ID allocation. */
392 EXTERN
bool _dl_tls_dtv_gaps
;
393 /* Highest dtv index currently needed. */
394 EXTERN
size_t _dl_tls_max_dtv_idx
;
395 /* Information about the dtv slots. */
396 EXTERN
struct dtv_slotinfo_list
399 struct dtv_slotinfo_list
*next
;
403 struct link_map
*map
;
405 } *_dl_tls_dtv_slotinfo_list
;
406 /* Number of modules in the static TLS block. */
407 EXTERN
size_t _dl_tls_static_nelem
;
408 /* Size of the static TLS block. */
409 EXTERN
size_t _dl_tls_static_size
;
410 /* Size actually allocated in the static TLS block. */
411 EXTERN
size_t _dl_tls_static_used
;
412 /* Alignment requirement of the static TLS block. */
413 EXTERN
size_t _dl_tls_static_align
;
415 /* Number of additional entries in the slotinfo array of each slotinfo
416 list element. A large number makes it almost certain take we never
417 have to iterate beyond the first element in the slotinfo list. */
418 #define TLS_SLOTINFO_SURPLUS (62)
420 /* Number of additional slots in the dtv allocated. */
421 #define DTV_SURPLUS (14)
423 /* Initial dtv of the main thread, not allocated with normal malloc. */
424 EXTERN
void *_dl_initial_dtv
;
425 /* Generation counter for the dtv. */
426 EXTERN
size_t _dl_tls_generation
;
428 EXTERN
void (*_dl_init_static_tls
) (struct link_map
*);
430 EXTERN
void (*_dl_wait_lookup_done
) (void);
432 /* Scopes to free after next THREAD_GSCOPE_WAIT (). */
433 EXTERN
struct dl_scope_free_list
437 } *_dl_scope_free_list
;
440 # define __rtld_global_attribute__
442 # ifdef HAVE_SDATA_SECTION
443 # define __rtld_local_attribute__ \
444 __attribute__ ((visibility ("hidden"), section (".sdata")))
445 # undef __rtld_global_attribute__
446 # define __rtld_global_attribute__ __attribute__ ((section (".sdata")))
448 # define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
450 extern struct rtld_global _rtld_local __rtld_local_attribute__
;
451 # undef __rtld_local_attribute__
453 extern struct rtld_global _rtld_global __rtld_global_attribute__
;
454 # undef __rtld_global_attribute__
458 # define GLRO(name) _##name
461 # define GLRO(name) _rtld_local_ro._##name
463 # define GLRO(name) _rtld_global_ro._##name
465 struct rtld_global_ro
469 /* If nonzero the appropriate debug information is printed. */
470 EXTERN
int _dl_debug_mask
;
471 #define DL_DEBUG_LIBS (1 << 0)
472 #define DL_DEBUG_IMPCALLS (1 << 1)
473 #define DL_DEBUG_BINDINGS (1 << 2)
474 #define DL_DEBUG_SYMBOLS (1 << 3)
475 #define DL_DEBUG_VERSIONS (1 << 4)
476 #define DL_DEBUG_RELOC (1 << 5)
477 #define DL_DEBUG_FILES (1 << 6)
478 #define DL_DEBUG_STATISTICS (1 << 7)
479 #define DL_DEBUG_UNUSED (1 << 8)
480 #define DL_DEBUG_SCOPES (1 << 9)
481 /* These two are used only internally. */
482 #define DL_DEBUG_HELP (1 << 10)
483 #define DL_DEBUG_PRELINK (1 << 11)
486 EXTERN
unsigned int _dl_osversion
;
488 EXTERN
const char *_dl_platform
;
489 EXTERN
size_t _dl_platformlen
;
491 /* Cached value of `getpagesize ()'. */
492 EXTERN
size_t _dl_pagesize
;
494 /* Do we read from ld.so.cache? */
495 EXTERN
int _dl_inhibit_cache
;
497 /* Copy of the content of `_dl_main_searchlist' at startup time. */
498 EXTERN
struct r_scope_elem _dl_initial_searchlist
;
500 /* CLK_TCK as reported by the kernel. */
501 EXTERN
int _dl_clktck
;
503 /* If nonzero print warnings messages. */
504 EXTERN
int _dl_verbose
;
506 /* File descriptor to write debug messages to. */
507 EXTERN
int _dl_debug_fd
;
509 /* Do we do lazy relocations? */
512 /* Nonzero if runtime lookups should not update the .got/.plt. */
513 EXTERN
int _dl_bind_not
;
515 /* Nonzero if references should be treated as weak during runtime
517 EXTERN
int _dl_dynamic_weak
;
519 /* Default floating-point control word. */
520 EXTERN fpu_control_t _dl_fpu_control
;
522 /* Expected cache ID. */
523 EXTERN
int _dl_correct_cache_id
;
525 /* Mask for hardware capabilities that are available. */
526 EXTERN
uint64_t _dl_hwcap
;
529 /* Mask for important hardware capabilities we honour. */
530 EXTERN
uint64_t _dl_hwcap_mask
;
533 #ifdef HAVE_AUX_VECTOR
534 /* Pointer to the auxv list supplied to the program at startup. */
535 EXTERN
ElfW(auxv_t
) *_dl_auxv
;
538 /* Get architecture specific definitions. */
539 #include <dl-procinfo.c>
541 /* Names of shared object for which the RPATH should be ignored. */
542 EXTERN
const char *_dl_inhibit_rpath
;
544 /* Location of the binary. */
545 EXTERN
const char *_dl_origin_path
;
547 /* -1 if the dynamic linker should honor library load bias,
548 0 if not, -2 use the default (honor biases for normal
549 binaries, don't honor for PIEs). */
550 EXTERN
ElfW(Addr
) _dl_use_load_bias
;
552 /* Name of the shared object to be profiled (if any). */
553 EXTERN
const char *_dl_profile
;
554 /* Filename of the output file. */
555 EXTERN
const char *_dl_profile_output
;
556 /* Name of the object we want to trace the prelinking. */
557 EXTERN
const char *_dl_trace_prelink
;
558 /* Map of shared object to be prelink traced. */
559 EXTERN
struct link_map
*_dl_trace_prelink_map
;
561 /* All search directories defined at startup. This is assigned a
562 non-NULL pointer by the ld.so startup code (after initialization
563 to NULL), so this can also serve as an indicator whether a copy
564 of ld.so is initialized and active. See the rtld_active function
566 EXTERN
struct r_search_path_elem
*_dl_init_all_dirs
;
568 #ifdef NEED_DL_SYSINFO
569 /* Syscall handling improvements. This is very specific to x86. */
570 EXTERN
uintptr_t _dl_sysinfo
;
573 #ifdef NEED_DL_SYSINFO_DSO
574 /* The vsyscall page is a virtual DSO pre-mapped by the kernel.
575 This points to its ELF header. */
576 EXTERN
const ElfW(Ehdr
) *_dl_sysinfo_dso
;
578 /* At startup time we set up the normal DSO data structure for it,
579 and this points to it. */
580 EXTERN
struct link_map
*_dl_sysinfo_map
;
583 /* Mask for more hardware capabilities that are available on some
585 EXTERN
uint64_t _dl_hwcap2
;
588 /* We add a function table to _rtld_global which is then used to
589 call the function instead of going through the PLT. The result
590 is that we can avoid exporting the functions and we do not jump
591 PLT relocations in libc.so. */
592 void (*_dl_debug_printf
) (const char *, ...)
593 __attribute__ ((__format__ (__printf__
, 1, 2)));
594 void (*_dl_mcount
) (ElfW(Addr
) frompc
, ElfW(Addr
) selfpc
);
595 lookup_t (*_dl_lookup_symbol_x
) (const char *, struct link_map
*,
596 const ElfW(Sym
) **, struct r_scope_elem
*[],
597 const struct r_found_version
*, int, int,
599 int (*_dl_check_caller
) (const void *, enum allowmask
);
600 void *(*_dl_open
) (const char *file
, int mode
, const void *caller_dlopen
,
601 Lmid_t nsid
, int argc
, char *argv
[], char *env
[]);
602 void (*_dl_close
) (void *map
);
603 void *(*_dl_tls_get_addr_soft
) (struct link_map
*);
604 #ifdef HAVE_DL_DISCOVER_OSVERSION
605 int (*_dl_discover_osversion
) (void);
608 /* List of auditing interfaces. */
609 struct audit_ifaces
*_dl_audit
;
610 unsigned int _dl_naudit
;
612 # define __rtld_global_attribute__
614 # define __rtld_local_attribute__ __attribute__ ((visibility ("hidden")))
615 extern struct rtld_global_ro _rtld_local_ro
616 attribute_relro __rtld_local_attribute__
;
617 extern struct rtld_global_ro _rtld_global_ro
618 attribute_relro __rtld_global_attribute__
;
619 # undef __rtld_local_attribute__
621 /* We cheat a bit here. We declare the variable as as const even
622 though it is at startup. */
623 extern const struct rtld_global_ro _rtld_global_ro
624 attribute_relro __rtld_global_attribute__
;
626 # undef __rtld_global_attribute__
631 /* dl-support.c defines these and initializes them early on. */
632 extern const ElfW(Phdr
) *_dl_phdr
;
633 extern size_t _dl_phnum
;
636 /* This is the initial value of GL(dl_make_stack_executable_hook).
637 A threads library can change it. */
638 extern int _dl_make_stack_executable (void **stack_endp
);
639 rtld_hidden_proto (_dl_make_stack_executable
)
641 /* Variable pointing to the end of the stack (or close to it). This value
642 must be constant over the runtime of the application. Some programs
643 might use the variable which results in copy relocations on some
644 platforms. But this does not matter, ld.so can always use the local
646 extern void *__libc_stack_end
647 #ifndef LIBC_STACK_END_NOT_RELRO
651 rtld_hidden_proto (__libc_stack_end
)
653 /* Parameters passed to the dynamic linker. */
654 extern int _dl_argc attribute_hidden attribute_relro
;
655 extern char **_dl_argv
656 #ifndef DL_ARGV_NOT_RELRO
660 rtld_hidden_proto (_dl_argv
)
662 extern unsigned int _dl_skip_args attribute_hidden
663 # ifndef DL_ARGV_NOT_RELRO
667 extern unsigned int _dl_skip_args_internal attribute_hidden
668 # ifndef DL_ARGV_NOT_RELRO
673 #define rtld_progname _dl_argv[0]
675 /* Flag set at startup and cleared when the last initializer has run. */
676 extern int _dl_starting_up
;
677 weak_extern (_dl_starting_up
)
678 rtld_hidden_proto (_dl_starting_up
)
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))) attribute_hidden
;
700 /* Write a message on the specified descriptor FD. The parameters are
701 interpreted as for a `printf' call. */
702 #if IS_IN (rtld) || !defined (SHARED)
703 extern void _dl_dprintf (int fd
, const char *fmt
, ...)
704 __attribute__ ((__format__ (__printf__
, 2, 3)))
707 __attribute__ ((always_inline
, __format__ (__printf__
, 2, 3)))
709 _dl_dprintf (int fd
, const char *fmt
, ...)
711 /* Use local declaration to avoid includign <stdio.h>. */
712 extern int __dprintf(int fd
, const char *format
, ...) attribute_hidden
;
713 __dprintf (fd
, fmt
, __builtin_va_arg_pack ());
717 /* Write a message on the specified descriptor standard output. The
718 parameters are interpreted as for a `printf' call. */
719 #define _dl_printf(fmt, args...) \
720 _dl_dprintf (STDOUT_FILENO, fmt, ##args)
722 /* Write a message on the specified descriptor standard error. The
723 parameters are interpreted as for a `printf' call. */
724 #define _dl_error_printf(fmt, args...) \
725 _dl_dprintf (STDERR_FILENO, fmt, ##args)
727 /* Write a message on the specified descriptor standard error and exit
728 the program. The parameters are interpreted as for a `printf' call. */
729 #define _dl_fatal_printf(fmt, args...) \
732 _dl_dprintf (STDERR_FILENO, fmt, ##args); \
738 /* An exception raised by the _dl_signal_error function family and
739 caught by _dl_catch_error function family. Exceptions themselves
740 are copied as part of the raise operation, but the strings are
745 const char *errstring
;
747 /* This buffer typically stores both objname and errstring
749 char *message_buffer
;
752 /* Creates a new exception. This calls malloc; if allocation fails,
753 dummy values are inserted. OBJECT is the name of the problematical
754 shared object, or null if its a general problem. ERRSTRING is a
755 string describing the specific problem. */
756 void _dl_exception_create (struct dl_exception
*, const char *object
,
757 const char *errstring
)
758 __attribute__ ((nonnull (1, 3)));
759 rtld_hidden_proto (_dl_exception_create
)
761 /* Like _dl_exception_create, but create errstring from a format
762 string FMT. Currently, only "%s" and "%%" are supported as format
764 void _dl_exception_create_format (struct dl_exception
*, const char *objname
,
765 const char *fmt
, ...)
766 __attribute__ ((nonnull (1, 3), format (printf
, 3, 4)));
767 rtld_hidden_proto (_dl_exception_create_format
)
769 /* Deallocate the exception, freeing allocated buffers (if
771 void _dl_exception_free (struct dl_exception
*)
772 __attribute__ ((nonnull (1)));
773 rtld_hidden_proto (_dl_exception_free
)
775 /* This function is called by all the internal dynamic linker
776 functions when they encounter an error. ERRCODE is either an
777 `errno' code or zero; it specifies the return value of
778 _dl_catch_error. OCCASION is included in the error message if the
779 process is terminated immediately. */
780 void _dl_signal_exception (int errcode
, struct dl_exception
*,
781 const char *occasion
)
782 __attribute__ ((__noreturn__
));
783 libc_hidden_proto (_dl_signal_exception
)
785 /* Like _dl_signal_exception, but creates the exception first. */
786 extern void _dl_signal_error (int errcode
, const char *object
,
787 const char *occasion
, const char *errstring
)
788 __attribute__ ((__noreturn__
));
789 libc_hidden_proto (_dl_signal_error
)
791 /* Like _dl_signal_exception, but may return when called in the
792 context of _dl_receive_error. This is only used during ld.so
793 bootstrap. In static and profiled builds, this is equivalent to
794 _dl_signal_exception. */
796 extern void _dl_signal_cexception (int errcode
, struct dl_exception
*,
797 const char *occasion
) attribute_hidden
;
799 __attribute__ ((always_inline
))
801 _dl_signal_cexception (int errcode
, struct dl_exception
*exception
,
802 const char *occasion
)
804 _dl_signal_exception (errcode
, exception
, occasion
);
808 /* See _dl_signal_cexception above. */
810 extern void _dl_signal_cerror (int errcode
, const char *object
,
811 const char *occasion
, const char *errstring
)
814 __attribute__ ((always_inline
))
816 _dl_signal_cerror (int errcode
, const char *object
,
817 const char *occasion
, const char *errstring
)
819 _dl_signal_error (errcode
, object
, occasion
, errstring
);
823 /* Call OPERATE, receiving errors from `dl_signal_cerror'. Unlike
824 `_dl_catch_error' the operation is resumed after the OPERATE
826 ARGS is passed as argument to OPERATE. */
827 extern void _dl_receive_error (receiver_fct fct
, void (*operate
) (void *),
828 void *args
) attribute_hidden
;
830 /* Call OPERATE, catching errors from `_dl_signal_error' and related
831 functions. If there is no error, *ERRSTRING is set to null. If
832 there is an error, *ERRSTRING is set to a string constructed from
833 the strings passed to _dl_signal_error, and the error code passed
834 is the return value and *OBJNAME is set to the object name which
835 experienced the problems. ERRSTRING if nonzero points to a
836 malloc'ed string which the caller has to free after use. ARGS is
837 passed as argument to OPERATE. MALLOCEDP is set to true only if
838 the returned string is allocated using the libc's malloc. */
839 extern int _dl_catch_error (const char **objname
, const char **errstring
,
840 bool *mallocedp
, void (*operate
) (void *),
842 libc_hidden_proto (_dl_catch_error
)
844 /* Call OPERATE (ARGS). If no error occurs, set *EXCEPTION to zero.
845 Otherwise, store a copy of the raised exception in *EXCEPTION,
846 which has to be freed by _dl_exception_free. */
847 int _dl_catch_exception (struct dl_exception
*exception
,
848 void (*operate
) (void *), void *args
);
849 libc_hidden_proto (_dl_catch_exception
)
851 /* Open the shared object NAME and map in its segments.
852 LOADER's DT_RPATH is used in searching for NAME.
853 If the object is already opened, returns its existing map. */
854 extern struct link_map
*_dl_map_object (struct link_map
*loader
,
856 int type
, int trace_mode
, int mode
,
857 Lmid_t nsid
) attribute_hidden
;
859 /* Call _dl_map_object on the dependencies of MAP, and set up
860 MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously
861 loaded objects that will be inserted into MAP->l_searchlist after MAP
862 but before its dependencies. */
863 extern void _dl_map_object_deps (struct link_map
*map
,
864 struct link_map
**preloads
,
865 unsigned int npreloads
, int trace_mode
,
869 /* Cache the locations of MAP's hash table. */
870 extern void _dl_setup_hash (struct link_map
*map
) attribute_hidden
;
873 /* Collect the directories in the search path for LOADER's dependencies.
874 The data structure is defined in <dlfcn.h>. If COUNTING is true,
875 SI->dls_cnt and SI->dls_size are set; if false, those must be as set
876 by a previous call with COUNTING set, and SI must point to SI->dls_size
877 bytes to be used in filling in the result. */
878 extern void _dl_rtld_di_serinfo (struct link_map
*loader
,
879 Dl_serinfo
*si
, bool counting
);
882 /* Search loaded objects' symbol tables for a definition of the symbol
883 referred to by UNDEF. *SYM is the symbol table entry containing the
884 reference; it is replaced with the defining symbol, and the base load
885 address of the defining object is returned. SYMBOL_SCOPE is a
886 null-terminated list of object scopes to search; each object's
887 l_searchlist (i.e. the segment of the dependency tree starting at that
888 object) is searched in turn. REFERENCE_NAME should name the object
889 containing the reference; it is used in error messages.
890 TYPE_CLASS describes the type of symbol we are looking for. */
893 /* If necessary add dependency between user and provider object. */
894 DL_LOOKUP_ADD_DEPENDENCY
= 1,
895 /* Return most recent version instead of default version for
896 unversioned lookup. */
897 DL_LOOKUP_RETURN_NEWEST
= 2,
898 /* Set if dl_lookup* called with GSCOPE lock held. */
899 DL_LOOKUP_GSCOPE_LOCK
= 4,
902 /* Lookup versioned symbol. */
903 extern lookup_t
_dl_lookup_symbol_x (const char *undef
,
904 struct link_map
*undef_map
,
905 const ElfW(Sym
) **sym
,
906 struct r_scope_elem
*symbol_scope
[],
907 const struct r_found_version
*version
,
908 int type_class
, int flags
,
909 struct link_map
*skip_map
)
913 /* Add the new link_map NEW to the end of the namespace list. */
914 extern void _dl_add_to_namespace_list (struct link_map
*new, Lmid_t nsid
)
917 /* Allocate a `struct link_map' for a new object being loaded. */
918 extern struct link_map
*_dl_new_object (char *realname
, const char *libname
,
919 int type
, struct link_map
*loader
,
920 int mode
, Lmid_t nsid
)
923 /* Relocate the given object (if it hasn't already been).
924 SCOPE is passed to _dl_lookup_symbol in symbol lookups.
925 If RTLD_LAZY is set in RELOC-MODE, don't relocate its PLT. */
926 extern void _dl_relocate_object (struct link_map
*map
,
927 struct r_scope_elem
*scope
[],
928 int reloc_mode
, int consider_profiling
)
931 /* Protect PT_GNU_RELRO area. */
932 extern void _dl_protect_relro (struct link_map
*map
) attribute_hidden
;
934 /* Call _dl_signal_error with a message about an unhandled reloc type.
935 TYPE is the result of ELFW(R_TYPE) (r_info), i.e. an R_<CPU>_* value.
936 PLT is nonzero if this was a PLT reloc; it just affects the message. */
937 extern void _dl_reloc_bad_type (struct link_map
*map
,
938 unsigned int type
, int plt
)
939 attribute_hidden
__attribute__ ((__noreturn__
));
941 /* Resolve conflicts if prelinking. */
942 extern void _dl_resolve_conflicts (struct link_map
*l
,
943 ElfW(Rela
) *conflict
,
944 ElfW(Rela
) *conflictend
)
947 /* Check the version dependencies of all objects available through
948 MAP. If VERBOSE print some more diagnostics. */
949 extern int _dl_check_all_versions (struct link_map
*map
, int verbose
,
950 int trace_mode
) attribute_hidden
;
952 /* Check the version dependencies for MAP. If VERBOSE print some more
954 extern int _dl_check_map_versions (struct link_map
*map
, int verbose
,
955 int trace_mode
) attribute_hidden
;
957 /* Initialize the object in SCOPE by calling the constructors with
958 ARGC, ARGV, and ENV as the parameters. */
959 extern void _dl_init (struct link_map
*main_map
, int argc
, char **argv
,
960 char **env
) attribute_hidden
;
962 /* Call the finalizer functions of all shared objects whose
963 initializer functions have completed. */
964 extern void _dl_fini (void) attribute_hidden
;
966 /* Sort array MAPS according to dependencies of the contained objects. */
967 extern void _dl_sort_maps (struct link_map
**maps
, unsigned int nmaps
,
968 char *used
, bool for_fini
) attribute_hidden
;
970 /* The dynamic linker calls this function before and having changing
971 any shared object mappings. The `r_state' member of `struct r_debug'
972 says what change is taking place. This function's address is
973 the value of the `r_brk' member. */
974 extern void _dl_debug_state (void);
975 rtld_hidden_proto (_dl_debug_state
)
977 /* Initialize `struct r_debug' if it has not already been done. The
978 argument is the run-time load address of the dynamic linker, to be put
979 in the `r_ldbase' member. Returns the address of the structure. */
980 extern struct r_debug
*_dl_debug_initialize (ElfW(Addr
) ldbase
, Lmid_t ns
)
983 /* Initialize the basic data structure for the search paths. */
984 extern void _dl_init_paths (const char *library_path
) attribute_hidden
;
986 /* Gather the information needed to install the profiling tables and start
988 extern void _dl_start_profile (void) attribute_hidden
;
990 /* The actual functions used to keep book on the calls. */
991 extern void _dl_mcount (ElfW(Addr
) frompc
, ElfW(Addr
) selfpc
);
992 rtld_hidden_proto (_dl_mcount
)
994 /* This function is simply a wrapper around the _dl_mcount function
995 which does not require a FROMPC parameter since this is the
997 extern void _dl_mcount_wrapper (void *selfpc
);
999 /* Show the members of the auxiliary array passed up from the kernel. */
1000 extern void _dl_show_auxv (void) attribute_hidden
;
1002 /* Return all environment variables starting with `LD_', one after the
1004 extern char *_dl_next_ld_env_entry (char ***position
) attribute_hidden
;
1006 /* Return an array with the names of the important hardware capabilities. */
1007 extern const struct r_strlenpair
*_dl_important_hwcaps (const char *platform
,
1008 size_t paltform_len
,
1010 size_t *max_capstrlen
)
1013 /* Look up NAME in ld.so.cache and return the file name stored there,
1014 or null if none is found. Caller must free returned string. */
1015 extern char *_dl_load_cache_lookup (const char *name
) attribute_hidden
;
1017 /* If the system does not support MAP_COPY we cannot leave the file open
1018 all the time since this would create problems when the file is replaced.
1019 Therefore we provide this function to close the file and open it again
1021 extern void _dl_unload_cache (void) attribute_hidden
;
1023 /* System-dependent function to read a file's whole contents in the
1024 most convenient manner available. *SIZEP gets the size of the
1025 file. On error MAP_FAILED is returned. */
1026 extern void *_dl_sysdep_read_whole_file (const char *file
, size_t *sizep
,
1027 int prot
) attribute_hidden
;
1029 /* System-specific function to do initial startup for the dynamic linker.
1030 After this, file access calls and getenv must work. This is responsible
1031 for setting __libc_enable_secure if we need to be secure (e.g. setuid),
1032 and for setting _dl_argc and _dl_argv, and then calling _dl_main. */
1033 extern ElfW(Addr
) _dl_sysdep_start (void **start_argptr
,
1034 void (*dl_main
) (const ElfW(Phdr
) *phdr
,
1036 ElfW(Addr
) *user_entry
,
1037 ElfW(auxv_t
) *auxv
))
1040 extern void _dl_sysdep_start_cleanup (void) attribute_hidden
;
1043 /* Determine next available module ID. */
1044 extern size_t _dl_next_tls_modid (void) attribute_hidden
;
1046 /* Count the modules with TLS segments. */
1047 extern size_t _dl_count_modids (void) attribute_hidden
;
1049 /* Calculate offset of the TLS blocks in the static TLS block. */
1050 extern void _dl_determine_tlsoffset (void) attribute_hidden
;
1053 /* Set up the TCB for statically linked applications. This is called
1054 early during startup because we always use TLS (for errno and the
1055 stack protector, among other things). */
1056 void __libc_setup_tls (void);
1058 # if ENABLE_STATIC_PIE
1059 /* Relocate static executable with PIE. */
1060 extern void _dl_relocate_static_pie (void) attribute_hidden
;
1062 /* Get a pointer to _dl_main_map. */
1063 extern struct link_map
* _dl_get_dl_main_map (void)
1064 __attribute__ ((visibility ("hidden")));
1066 # define _dl_relocate_static_pie()
1069 /* Initialization of libpthread for statically linked applications.
1070 If libpthread is not linked in, this is an empty function. */
1071 void __pthread_initialize_minimal (void) weak_function
;
1074 /* Allocate memory for static TLS block (unless MEM is nonzero) and dtv. */
1075 extern void *_dl_allocate_tls (void *mem
);
1076 rtld_hidden_proto (_dl_allocate_tls
)
1078 /* Get size and alignment requirements of the static TLS block. */
1079 extern void _dl_get_tls_static_info (size_t *sizep
, size_t *alignp
);
1081 extern void _dl_allocate_static_tls (struct link_map
*map
) attribute_hidden
;
1083 /* These are internal entry points to the two halves of _dl_allocate_tls,
1084 only used within rtld.c itself at startup time. */
1085 extern void *_dl_allocate_tls_storage (void) attribute_hidden
;
1086 extern void *_dl_allocate_tls_init (void *);
1087 rtld_hidden_proto (_dl_allocate_tls_init
)
1089 /* Deallocate memory allocated with _dl_allocate_tls. */
1090 extern void _dl_deallocate_tls (void *tcb
, bool dealloc_tcb
);
1091 rtld_hidden_proto (_dl_deallocate_tls
)
1093 extern void _dl_nothread_init_static_tls (struct link_map
*) attribute_hidden
;
1095 /* Find origin of the executable. */
1096 extern const char *_dl_get_origin (void) attribute_hidden
;
1099 extern size_t _dl_dst_count (const char *name
) attribute_hidden
;
1101 /* Substitute DST values. */
1102 extern char *_dl_dst_substitute (struct link_map
*l
, const char *name
,
1103 char *result
) attribute_hidden
;
1105 /* Check validity of the caller. */
1106 extern int _dl_check_caller (const void *caller
, enum allowmask mask
)
1109 /* Open the shared object NAME, relocate it, and run its initializer if it
1110 hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If
1111 the object is already opened, returns its existing map. */
1112 extern void *_dl_open (const char *name
, int mode
, const void *caller
,
1113 Lmid_t nsid
, int argc
, char *argv
[], char *env
[])
1116 /* Free or queue for freeing scope OLD. If other threads might be
1117 in the middle of _dl_fixup, _dl_profile_fixup or dl*sym using the
1118 old scope, OLD can't be freed until no thread is using it. */
1119 extern int _dl_scope_free (void *) attribute_hidden
;
1121 /* Add module to slot information data. */
1122 extern void _dl_add_to_slotinfo (struct link_map
*l
) attribute_hidden
;
1124 /* Update slot information data for at least the generation of the
1125 module with the given index. */
1126 extern struct link_map
*_dl_update_slotinfo (unsigned long int req_modid
)
1129 /* Look up the module's TLS block as for __tls_get_addr,
1130 but never touch anything. Return null if it's not allocated yet. */
1131 extern void *_dl_tls_get_addr_soft (struct link_map
*l
) attribute_hidden
;
1133 extern int _dl_addr_inside_object (struct link_map
*l
, const ElfW(Addr
) addr
)
1136 /* Show show of an object. */
1137 extern void _dl_show_scope (struct link_map
*new, int from
)
1140 extern struct link_map
*_dl_find_dso_for_object (const ElfW(Addr
) addr
);
1141 rtld_hidden_proto (_dl_find_dso_for_object
)
1143 /* Initialization which is normally done by the dynamic linker. */
1144 extern void _dl_non_dynamic_init (void)
1147 /* Used by static binaries to check the auxiliary vector. */
1148 extern void _dl_aux_init (ElfW(auxv_t
) *av
)
1151 /* Return true if the ld.so copy in this namespace is actually active
1152 and working. If false, the dl_open/dlfcn hooks have to be used to
1153 call into the outer dynamic linker (which happens after static
1159 /* The default-initialized variable does not have a non-zero
1160 dl_init_all_dirs member, so this allows us to recognize an
1161 initialized and active ld.so copy. */
1162 return GLRO(dl_init_all_dirs
) != NULL
;
1168 #endif /* ldsodefs.h */