1 /* Run time dynamic linker.
2 Copyright (C) 1995-2017 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/>. */
27 #include <sys/param.h>
32 #include <fpu_control.h>
33 #include <hp-timing.h>
34 #include <libc-lock.h>
35 #include "dynamic-link.h"
36 #include <dl-librecon.h>
37 #include <unsecvars.h>
39 #include <dl-osinfo.h>
40 #include <dl-procinfo.h>
42 #include <stap-probe.h>
43 #include <stackinfo.h>
47 /* Avoid PLT use for our local calls at startup. */
48 extern __typeof (__mempcpy
) __mempcpy attribute_hidden
;
50 /* GCC has mental blocks about _exit. */
51 extern __typeof (_exit
) exit_internal
asm ("_exit") attribute_hidden
;
52 #define _exit exit_internal
54 /* Helper function to handle errors while resolving symbols. */
55 static void print_unresolved (int errcode
, const char *objname
,
56 const char *errsting
);
58 /* Helper function to handle errors when a version is missing. */
59 static void print_missing_version (int errcode
, const char *objname
,
60 const char *errsting
);
62 /* Print the various times we collected. */
63 static void print_statistics (hp_timing_t
*total_timep
);
65 /* Add audit objects. */
66 static void process_dl_audit (char *str
);
68 /* This is a list of all the modes the dynamic loader can be in. */
69 enum mode
{ normal
, list
, verify
, trace
};
71 /* Process all environments variables the dynamic linker must recognize.
72 Since all of them start with `LD_' we are a bit smarter while finding
74 static void process_envvars (enum mode
*modep
);
76 #ifdef DL_ARGV_NOT_RELRO
77 int _dl_argc attribute_hidden
;
78 char **_dl_argv
= NULL
;
79 /* Nonzero if we were run directly. */
80 unsigned int _dl_skip_args attribute_hidden
;
82 int _dl_argc attribute_relro attribute_hidden
;
83 char **_dl_argv attribute_relro
= NULL
;
84 unsigned int _dl_skip_args attribute_relro attribute_hidden
;
86 rtld_hidden_data_def (_dl_argv
)
88 #ifndef THREAD_SET_STACK_GUARD
89 /* Only exported for architectures that don't store the stack guard canary
90 in thread local area. */
91 uintptr_t __stack_chk_guard attribute_relro
;
94 /* Only exported for architectures that don't store the pointer guard
95 value in thread local area. */
96 uintptr_t __pointer_chk_guard_local
97 attribute_relro attribute_hidden
__attribute__ ((nocommon
));
98 #ifndef THREAD_SET_POINTER_GUARD
99 strong_alias (__pointer_chk_guard_local
, __pointer_chk_guard
)
103 /* List of auditing DSOs. */
104 static struct audit_list
107 struct audit_list
*next
;
110 #ifndef HAVE_INLINED_SYSCALLS
111 /* Set nonzero during loading and initialization of executable and
112 libraries, cleared before the executable's entry point runs. This
113 must not be initialized to nonzero, because the unused dynamic
114 linker loaded in for libc.so's "ld.so.1" dep will provide the
115 definition seen by libc.so's initializer; that value must be zero,
116 and will be since that dynamic linker's _dl_start and dl_main will
118 int _dl_starting_up
= 0;
119 rtld_hidden_def (_dl_starting_up
)
122 /* This is the structure which defines all variables global to ld.so
123 (except those which cannot be added for some reason). */
124 struct rtld_global _rtld_global
=
126 /* Generally the default presumption without further information is an
127 * executable stack but this is not true for all platforms. */
128 ._dl_stack_flags
= DEFAULT_STACK_PERMS
,
129 #ifdef _LIBC_REENTRANT
130 ._dl_load_lock
= _RTLD_LOCK_RECURSIVE_INITIALIZER
,
131 ._dl_load_write_lock
= _RTLD_LOCK_RECURSIVE_INITIALIZER
,
136 #ifdef _LIBC_REENTRANT
137 [LM_ID_BASE
] = { ._ns_unique_sym_table
138 = { .lock
= _RTLD_LOCK_RECURSIVE_INITIALIZER
} }
142 /* If we would use strong_alias here the compiler would see a
143 non-hidden definition. This would undo the effect of the previous
144 declaration. So spell out was strong_alias does plus add the
145 visibility attribute. */
146 extern struct rtld_global _rtld_local
147 __attribute__ ((alias ("_rtld_global"), visibility ("hidden")));
150 /* This variable is similar to _rtld_local, but all values are
151 read-only after relocation. */
152 struct rtld_global_ro _rtld_global_ro attribute_relro
=
154 /* Get architecture specific initializer. */
155 #include <dl-procinfo.c>
156 #ifdef NEED_DL_SYSINFO
157 ._dl_sysinfo
= DL_SYSINFO_DEFAULT
,
159 ._dl_debug_fd
= STDERR_FILENO
,
160 ._dl_use_load_bias
= -2,
161 ._dl_correct_cache_id
= _DL_CACHE_DEFAULT_ID
,
162 ._dl_hwcap_mask
= HWCAP_IMPORTANT
,
164 ._dl_fpu_control
= _FPU_DEFAULT
,
165 ._dl_pagesize
= EXEC_PAGESIZE
,
166 ._dl_inhibit_cache
= 0,
168 /* Function pointers. */
169 ._dl_debug_printf
= _dl_debug_printf
,
170 ._dl_mcount
= _dl_mcount
,
171 ._dl_lookup_symbol_x
= _dl_lookup_symbol_x
,
172 ._dl_check_caller
= _dl_check_caller
,
173 ._dl_open
= _dl_open
,
174 ._dl_close
= _dl_close
,
175 ._dl_tls_get_addr_soft
= _dl_tls_get_addr_soft
,
176 #ifdef HAVE_DL_DISCOVER_OSVERSION
177 ._dl_discover_osversion
= _dl_discover_osversion
180 /* If we would use strong_alias here the compiler would see a
181 non-hidden definition. This would undo the effect of the previous
182 declaration. So spell out was strong_alias does plus add the
183 visibility attribute. */
184 extern struct rtld_global_ro _rtld_local_ro
185 __attribute__ ((alias ("_rtld_global_ro"), visibility ("hidden")));
188 static void dl_main (const ElfW(Phdr
) *phdr
, ElfW(Word
) phnum
,
189 ElfW(Addr
) *user_entry
, ElfW(auxv_t
) *auxv
);
191 /* These two variables cannot be moved into .data.rel.ro. */
192 static struct libname_list _dl_rtld_libname
;
193 static struct libname_list _dl_rtld_libname2
;
195 /* Variable for statistics. */
196 #ifndef HP_TIMING_NONAVAIL
197 static hp_timing_t relocate_time
;
198 static hp_timing_t load_time attribute_relro
;
199 static hp_timing_t start_time attribute_relro
;
202 /* Additional definitions needed by TLS initialization. */
203 #ifdef TLS_INIT_HELPER
207 /* Helper function for syscall implementation. */
208 #ifdef DL_SYSINFO_IMPLEMENTATION
209 DL_SYSINFO_IMPLEMENTATION
212 /* Before ld.so is relocated we must not access variables which need
213 relocations. This means variables which are exported. Variables
214 declared as static are fine. If we can mark a variable hidden this
215 is fine, too. The latter is important here. We can avoid setting
216 up a temporary link map for ld.so if we can mark _rtld_global as
218 #ifdef PI_STATIC_AND_HIDDEN
219 # define DONT_USE_BOOTSTRAP_MAP 1
222 #ifdef DONT_USE_BOOTSTRAP_MAP
223 static ElfW(Addr
) _dl_start_final (void *arg
);
225 struct dl_start_final_info
228 #if !defined HP_TIMING_NONAVAIL && HP_TIMING_INLINE
229 hp_timing_t start_time
;
232 static ElfW(Addr
) _dl_start_final (void *arg
,
233 struct dl_start_final_info
*info
);
236 /* These defined magically in the linker script. */
237 extern char _begin
[] attribute_hidden
;
238 extern char _etext
[] attribute_hidden
;
239 extern char _end
[] attribute_hidden
;
245 # error "sysdeps/MACHINE/dl-machine.h fails to define RTLD_START"
248 /* This is the second half of _dl_start (below). It can be inlined safely
249 under DONT_USE_BOOTSTRAP_MAP, where it is careful not to make any GOT
250 references. When the tools don't permit us to avoid using a GOT entry
251 for _dl_rtld_global (no attribute_hidden support), we must make sure
252 this function is not inlined (see below). */
254 #ifdef DONT_USE_BOOTSTRAP_MAP
255 static inline ElfW(Addr
) __attribute__ ((always_inline
))
256 _dl_start_final (void *arg
)
258 static ElfW(Addr
) __attribute__ ((noinline
))
259 _dl_start_final (void *arg
, struct dl_start_final_info
*info
)
262 ElfW(Addr
) start_addr
;
264 if (HP_SMALL_TIMING_AVAIL
)
266 /* If it hasn't happen yet record the startup time. */
267 if (! HP_TIMING_INLINE
)
268 HP_TIMING_NOW (start_time
);
269 #if !defined DONT_USE_BOOTSTRAP_MAP && !defined HP_TIMING_NONAVAIL
271 start_time
= info
->start_time
;
275 /* Transfer data about ourselves to the permanent link_map structure. */
276 #ifndef DONT_USE_BOOTSTRAP_MAP
277 GL(dl_rtld_map
).l_addr
= info
->l
.l_addr
;
278 GL(dl_rtld_map
).l_ld
= info
->l
.l_ld
;
279 memcpy (GL(dl_rtld_map
).l_info
, info
->l
.l_info
,
280 sizeof GL(dl_rtld_map
).l_info
);
281 GL(dl_rtld_map
).l_mach
= info
->l
.l_mach
;
282 GL(dl_rtld_map
).l_relocated
= 1;
284 _dl_setup_hash (&GL(dl_rtld_map
));
285 GL(dl_rtld_map
).l_real
= &GL(dl_rtld_map
);
286 GL(dl_rtld_map
).l_map_start
= (ElfW(Addr
)) _begin
;
287 GL(dl_rtld_map
).l_map_end
= (ElfW(Addr
)) _end
;
288 GL(dl_rtld_map
).l_text_end
= (ElfW(Addr
)) _etext
;
289 /* Copy the TLS related data if necessary. */
290 #ifndef DONT_USE_BOOTSTRAP_MAP
291 # if NO_TLS_OFFSET != 0
292 GL(dl_rtld_map
).l_tls_offset
= NO_TLS_OFFSET
;
296 HP_TIMING_NOW (GL(dl_cpuclock_offset
));
298 /* Initialize the stack end variable. */
299 __libc_stack_end
= __builtin_frame_address (0);
301 /* Call the OS-dependent function to set up life so we can do things like
302 file access. It will call `dl_main' (below) to do all the real work
303 of the dynamic linker, and then unwind our frame and run the user
304 entry point on the same stack we entered on. */
305 start_addr
= _dl_sysdep_start (arg
, &dl_main
);
307 #ifndef HP_TIMING_NONAVAIL
308 hp_timing_t rtld_total_time
;
309 if (HP_SMALL_TIMING_AVAIL
)
311 hp_timing_t end_time
;
313 /* Get the current time. */
314 HP_TIMING_NOW (end_time
);
316 /* Compute the difference. */
317 HP_TIMING_DIFF (rtld_total_time
, start_time
, end_time
);
321 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_STATISTICS
))
323 #ifndef HP_TIMING_NONAVAIL
324 print_statistics (&rtld_total_time
);
326 print_statistics (NULL
);
333 static ElfW(Addr
) __attribute_used__ internal_function
334 _dl_start (void *arg
)
336 #ifdef DONT_USE_BOOTSTRAP_MAP
337 # define bootstrap_map GL(dl_rtld_map)
339 struct dl_start_final_info info
;
340 # define bootstrap_map info.l
343 /* This #define produces dynamic linking inline functions for
344 bootstrap relocation instead of general-purpose relocation.
345 Since ld.so must not have any undefined symbols the result
346 is trivial: always the map of ld.so itself. */
347 #define RTLD_BOOTSTRAP
348 #define RESOLVE_MAP(sym, version, flags) (&bootstrap_map)
349 #include "dynamic-link.h"
351 if (HP_TIMING_INLINE
&& HP_SMALL_TIMING_AVAIL
)
352 #ifdef DONT_USE_BOOTSTRAP_MAP
353 HP_TIMING_NOW (start_time
);
355 HP_TIMING_NOW (info
.start_time
);
358 /* Partly clean the `bootstrap_map' structure up. Don't use
359 `memset' since it might not be built in or inlined and we cannot
360 make function calls at this point. Use '__builtin_memset' if we
361 know it is available. We do not have to clear the memory if we
362 do not have to use the temporary bootstrap_map. Global variables
363 are initialized to zero by default. */
364 #ifndef DONT_USE_BOOTSTRAP_MAP
365 # ifdef HAVE_BUILTIN_MEMSET
366 __builtin_memset (bootstrap_map
.l_info
, '\0', sizeof (bootstrap_map
.l_info
));
369 cnt
< sizeof (bootstrap_map
.l_info
) / sizeof (bootstrap_map
.l_info
[0]);
371 bootstrap_map
.l_info
[cnt
] = 0;
375 /* Figure out the run-time load address of the dynamic linker itself. */
376 bootstrap_map
.l_addr
= elf_machine_load_address ();
378 /* Read our own dynamic section and fill in the info array. */
379 bootstrap_map
.l_ld
= (void *) bootstrap_map
.l_addr
+ elf_machine_dynamic ();
380 elf_get_dynamic_info (&bootstrap_map
, NULL
);
382 #if NO_TLS_OFFSET != 0
383 bootstrap_map
.l_tls_offset
= NO_TLS_OFFSET
;
386 #ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
387 ELF_MACHINE_BEFORE_RTLD_RELOC (bootstrap_map
.l_info
);
390 if (bootstrap_map
.l_addr
|| ! bootstrap_map
.l_info
[VALIDX(DT_GNU_PRELINKED
)])
392 /* Relocate ourselves so we can do normal function calls and
393 data access using the global offset table. */
395 ELF_DYNAMIC_RELOCATE (&bootstrap_map
, 0, 0, 0);
397 bootstrap_map
.l_relocated
= 1;
399 /* Please note that we don't allow profiling of this object and
400 therefore need not test whether we have to allocate the array
401 for the relocation results (as done in dl-reloc.c). */
403 /* Now life is sane; we can call functions and access global data.
404 Set up to use the operating system facilities, and find out from
405 the operating system's program loader where to find the program
406 header table in core. Put the rest of _dl_start into a separate
407 function, that way the compiler cannot put accesses to the GOT
408 before ELF_DYNAMIC_RELOCATE. */
410 #ifdef DONT_USE_BOOTSTRAP_MAP
411 ElfW(Addr
) entry
= _dl_start_final (arg
);
413 ElfW(Addr
) entry
= _dl_start_final (arg
, &info
);
416 #ifndef ELF_MACHINE_START_ADDRESS
417 # define ELF_MACHINE_START_ADDRESS(map, start) (start)
420 return ELF_MACHINE_START_ADDRESS (GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
, entry
);
426 /* Now life is peachy; we can do all normal operations.
427 On to the real work. */
429 /* Some helper functions. */
431 /* Arguments to relocate_doit. */
440 /* Argument to map_doit. */
442 struct link_map
*loader
;
444 /* Return value of map_doit. */
445 struct link_map
*map
;
451 struct link_map
*map
;
457 struct link_map
*map
;
461 /* Arguments to version_check_doit. */
462 struct version_check_args
469 relocate_doit (void *a
)
471 struct relocate_args
*args
= (struct relocate_args
*) a
;
473 _dl_relocate_object (args
->l
, args
->l
->l_scope
, args
->reloc_mode
, 0);
479 struct map_args
*args
= (struct map_args
*) a
;
480 int type
= (args
->mode
== __RTLD_OPENEXEC
) ? lt_executable
: lt_library
;
481 args
->map
= _dl_map_object (args
->loader
, args
->str
, type
, 0,
482 args
->mode
, LM_ID_BASE
);
486 dlmopen_doit (void *a
)
488 struct dlmopen_args
*args
= (struct dlmopen_args
*) a
;
489 args
->map
= _dl_open (args
->fname
,
490 (RTLD_LAZY
| __RTLD_DLOPEN
| __RTLD_AUDIT
492 dl_main
, LM_ID_NEWLM
, _dl_argc
, _dl_argv
,
497 lookup_doit (void *a
)
499 struct lookup_args
*args
= (struct lookup_args
*) a
;
500 const ElfW(Sym
) *ref
= NULL
;
502 lookup_t l
= _dl_lookup_symbol_x (args
->name
, args
->map
, &ref
,
503 args
->map
->l_local_scope
, NULL
, 0,
504 DL_LOOKUP_RETURN_NEWEST
, NULL
);
506 args
->result
= DL_SYMBOL_ADDRESS (l
, ref
);
510 version_check_doit (void *a
)
512 struct version_check_args
*args
= (struct version_check_args
*) a
;
513 if (_dl_check_all_versions (GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
, 1,
514 args
->dotrace
) && args
->doexit
)
515 /* We cannot start the application. Abort now. */
520 static inline struct link_map
*
521 find_needed (const char *name
)
523 struct r_scope_elem
*scope
= &GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
->l_searchlist
;
524 unsigned int n
= scope
->r_nlist
;
527 if (_dl_name_match_p (name
, scope
->r_list
[n
]))
528 return scope
->r_list
[n
];
530 /* Should never happen. */
535 match_version (const char *string
, struct link_map
*map
)
537 const char *strtab
= (const void *) D_PTR (map
, l_info
[DT_STRTAB
]);
540 #define VERDEFTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERDEF))
541 if (map
->l_info
[VERDEFTAG
] == NULL
)
542 /* The file has no symbol versioning. */
545 def
= (ElfW(Verdef
) *) ((char *) map
->l_addr
546 + map
->l_info
[VERDEFTAG
]->d_un
.d_ptr
);
549 ElfW(Verdaux
) *aux
= (ElfW(Verdaux
) *) ((char *) def
+ def
->vd_aux
);
551 /* Compare the version strings. */
552 if (strcmp (string
, strtab
+ aux
->vda_name
) == 0)
556 /* If no more definitions we failed to find what we want. */
557 if (def
->vd_next
== 0)
560 /* Next definition. */
561 def
= (ElfW(Verdef
) *) ((char *) def
+ def
->vd_next
);
567 static bool tls_init_tp_called
;
572 /* Number of elements in the static TLS block. */
573 GL(dl_tls_static_nelem
) = GL(dl_tls_max_dtv_idx
);
575 /* Do not do this twice. The audit interface might have required
576 the DTV interfaces to be set up early. */
577 if (GL(dl_initial_dtv
) != NULL
)
580 /* Allocate the array which contains the information about the
581 dtv slots. We allocate a few entries more than needed to
582 avoid the need for reallocation. */
583 size_t nelem
= GL(dl_tls_max_dtv_idx
) + 1 + TLS_SLOTINFO_SURPLUS
;
586 GL(dl_tls_dtv_slotinfo_list
) = (struct dtv_slotinfo_list
*)
587 calloc (sizeof (struct dtv_slotinfo_list
)
588 + nelem
* sizeof (struct dtv_slotinfo
), 1);
589 /* No need to check the return value. If memory allocation failed
590 the program would have been terminated. */
592 struct dtv_slotinfo
*slotinfo
= GL(dl_tls_dtv_slotinfo_list
)->slotinfo
;
593 GL(dl_tls_dtv_slotinfo_list
)->len
= nelem
;
594 GL(dl_tls_dtv_slotinfo_list
)->next
= NULL
;
596 /* Fill in the information from the loaded modules. No namespace
597 but the base one can be filled at this time. */
598 assert (GL(dl_ns
)[LM_ID_BASE
+ 1]._ns_loaded
== NULL
);
600 for (struct link_map
*l
= GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
; l
!= NULL
;
602 if (l
->l_tls_blocksize
!= 0)
604 /* This is a module with TLS data. Store the map reference.
605 The generation counter is zero. */
607 /* slotinfo[i].gen = 0; */
610 assert (i
== GL(dl_tls_max_dtv_idx
));
612 /* Compute the TLS offsets for the various blocks. */
613 _dl_determine_tlsoffset ();
615 /* Construct the static TLS block and the dtv for the initial
616 thread. For some platforms this will include allocating memory
617 for the thread descriptor. The memory for the TLS block will
618 never be freed. It should be allocated accordingly. The dtv
619 array can be changed if dynamic loading requires it. */
620 void *tcbp
= _dl_allocate_tls_storage ();
623 cannot allocate TLS data structures for initial thread");
625 /* Store for detection of the special case by __tls_get_addr
626 so it knows not to pass this dtv to the normal realloc. */
627 GL(dl_initial_dtv
) = GET_DTV (tcbp
);
629 /* And finally install it for the main thread. */
630 const char *lossage
= TLS_INIT_TP (tcbp
);
631 if (__glibc_unlikely (lossage
!= NULL
))
632 _dl_fatal_printf ("cannot set up thread-local storage: %s\n", lossage
);
633 tls_init_tp_called
= true;
639 do_preload (const char *fname
, struct link_map
*main_map
, const char *where
)
642 const char *err_str
= NULL
;
643 struct map_args args
;
647 args
.loader
= main_map
;
648 args
.mode
= __RTLD_SECURE
;
650 unsigned int old_nloaded
= GL(dl_ns
)[LM_ID_BASE
]._ns_nloaded
;
652 (void) _dl_catch_error (&objname
, &err_str
, &malloced
, map_doit
, &args
);
653 if (__glibc_unlikely (err_str
!= NULL
))
656 ERROR: ld.so: object '%s' from %s cannot be preloaded (%s): ignored.\n",
657 fname
, where
, err_str
);
658 /* No need to call free, this is still before
659 the libc's malloc is used. */
661 else if (GL(dl_ns
)[LM_ID_BASE
]._ns_nloaded
!= old_nloaded
)
662 /* It is no duplicate. */
665 /* Nothing loaded. */
669 #if defined SHARED && defined _LIBC_REENTRANT \
670 && defined __rtld_lock_default_lock_recursive
672 rtld_lock_default_lock_recursive (void *lock
)
674 __rtld_lock_default_lock_recursive (lock
);
678 rtld_lock_default_unlock_recursive (void *lock
)
680 __rtld_lock_default_unlock_recursive (lock
);
688 /* Set up the stack checker's canary. */
689 uintptr_t stack_chk_guard
= _dl_setup_stack_chk_guard (_dl_random
);
690 #ifdef THREAD_SET_STACK_GUARD
691 THREAD_SET_STACK_GUARD (stack_chk_guard
);
693 __stack_chk_guard
= stack_chk_guard
;
696 /* Set up the pointer guard as well, if necessary. */
697 uintptr_t pointer_chk_guard
698 = _dl_setup_pointer_guard (_dl_random
, stack_chk_guard
);
699 #ifdef THREAD_SET_POINTER_GUARD
700 THREAD_SET_POINTER_GUARD (pointer_chk_guard
);
702 __pointer_chk_guard_local
= pointer_chk_guard
;
704 /* We do not need the _dl_random value anymore. The less
705 information we leave behind, the better, so clear the
710 #include "setup-vdso.h"
712 /* The library search path. */
713 static const char *library_path attribute_relro
;
714 /* The list preloaded objects. */
715 static const char *preloadlist attribute_relro
;
716 /* Nonzero if information about versions has to be printed. */
717 static int version_info attribute_relro
;
720 dl_main (const ElfW(Phdr
) *phdr
,
722 ElfW(Addr
) *user_entry
,
725 const ElfW(Phdr
) *ph
;
727 struct link_map
*main_map
;
730 bool has_interp
= false;
732 bool prelinked
= false;
733 bool rtld_is_main
= false;
734 #ifndef HP_TIMING_NONAVAIL
741 GL(dl_init_static_tls
) = &_dl_nothread_init_static_tls
;
743 #if defined SHARED && defined _LIBC_REENTRANT \
744 && defined __rtld_lock_default_lock_recursive
745 GL(dl_rtld_lock_recursive
) = rtld_lock_default_lock_recursive
;
746 GL(dl_rtld_unlock_recursive
) = rtld_lock_default_unlock_recursive
;
749 /* The explicit initialization here is cheaper than processing the reloc
750 in the _rtld_local definition's initializer. */
751 GL(dl_make_stack_executable_hook
) = &_dl_make_stack_executable
;
753 /* Process the environment variable which control the behaviour. */
754 process_envvars (&mode
);
756 #ifndef HAVE_INLINED_SYSCALLS
757 /* Set up a flag which tells we are just starting. */
761 if (*user_entry
== (ElfW(Addr
)) ENTRY_POINT
)
763 /* Ho ho. We are not the program interpreter! We are the program
764 itself! This means someone ran ld.so as a command. Well, that
765 might be convenient to do sometimes. We support it by
766 interpreting the args like this:
768 ld.so PROGRAM ARGS...
770 The first argument is the name of a file containing an ELF
771 executable we will load and run with the following arguments.
772 To simplify life here, PROGRAM is searched for using the
773 normal rules for shared objects, rather than $PATH or anything
774 like that. We just load it and use its entry point; we don't
775 pay attention to its PT_INTERP command (we are the interpreter
776 ourselves). This is an easy way to test a new ld.so before
780 /* Note the place where the dynamic linker actually came from. */
781 GL(dl_rtld_map
).l_name
= rtld_progname
;
784 if (! strcmp (_dl_argv
[1], "--list"))
787 GLRO(dl_lazy
) = -1; /* This means do no dependency analysis. */
793 else if (! strcmp (_dl_argv
[1], "--verify"))
801 else if (! strcmp (_dl_argv
[1], "--inhibit-cache"))
803 GLRO(dl_inhibit_cache
) = 1;
808 else if (! strcmp (_dl_argv
[1], "--library-path")
811 library_path
= _dl_argv
[2];
817 else if (! strcmp (_dl_argv
[1], "--inhibit-rpath")
820 GLRO(dl_inhibit_rpath
) = _dl_argv
[2];
826 else if (! strcmp (_dl_argv
[1], "--audit") && _dl_argc
> 2)
828 process_dl_audit (_dl_argv
[2]);
837 /* If we have no further argument the program was called incorrectly.
838 Grant the user some education. */
841 Usage: ld.so [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\
842 You have invoked `ld.so', the helper program for shared library executables.\n\
843 This program usually lives in the file `/lib/ld.so', and special directives\n\
844 in executable files using ELF shared libraries tell the system's program\n\
845 loader to load the helper program from this file. This helper program loads\n\
846 the shared libraries needed by the program executable, prepares the program\n\
847 to run, and runs it. You may invoke this helper program directly from the\n\
848 command line to load and run an ELF executable file; this is like executing\n\
849 that file itself, but always uses this helper program from the file you\n\
850 specified, instead of the helper program file specified in the executable\n\
851 file you run. This is mostly of use for maintainers to test new versions\n\
852 of this helper program; chances are you did not intend to run this program.\n\
854 --list list all dependencies and how they are resolved\n\
855 --verify verify that given object really is a dynamically linked\n\
856 object we can handle\n\
857 --inhibit-cache Do not use " LD_SO_CACHE
"\n\
858 --library-path PATH use given PATH instead of content of the environment\n\
859 variable LD_LIBRARY_PATH\n\
860 --inhibit-rpath LIST ignore RUNPATH and RPATH information in object names\n\
862 --audit LIST use objects named in LIST as auditors\n");
868 /* The initialization of _dl_stack_flags done below assumes the
869 executable's PT_GNU_STACK may have been honored by the kernel, and
870 so a PT_GNU_STACK with PF_X set means the stack started out with
871 execute permission. However, this is not really true if the
872 dynamic linker is the executable the kernel loaded. For this
873 case, we must reinitialize _dl_stack_flags to match the dynamic
874 linker itself. If the dynamic linker was built with a
875 PT_GNU_STACK, then the kernel may have loaded us with a
876 nonexecutable stack that we will have to make executable when we
877 load the program below unless it has a PT_GNU_STACK indicating
878 nonexecutable stack is ok. */
880 for (ph
= phdr
; ph
< &phdr
[phnum
]; ++ph
)
881 if (ph
->p_type
== PT_GNU_STACK
)
883 GL(dl_stack_flags
) = ph
->p_flags
;
887 if (__builtin_expect (mode
, normal
) == verify
)
890 const char *err_str
= NULL
;
891 struct map_args args
;
894 args
.str
= rtld_progname
;
896 args
.mode
= __RTLD_OPENEXEC
;
897 (void) _dl_catch_error (&objname
, &err_str
, &malloced
, map_doit
,
899 if (__glibc_unlikely (err_str
!= NULL
))
900 /* We don't free the returned string, the programs stops
902 _exit (EXIT_FAILURE
);
906 HP_TIMING_NOW (start
);
907 _dl_map_object (NULL
, rtld_progname
, lt_executable
, 0,
908 __RTLD_OPENEXEC
, LM_ID_BASE
);
909 HP_TIMING_NOW (stop
);
911 HP_TIMING_DIFF (load_time
, start
, stop
);
914 /* Now the map for the main executable is available. */
915 main_map
= GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
;
917 if (__builtin_expect (mode
, normal
) == normal
918 && GL(dl_rtld_map
).l_info
[DT_SONAME
] != NULL
919 && main_map
->l_info
[DT_SONAME
] != NULL
920 && strcmp ((const char *) D_PTR (&GL(dl_rtld_map
), l_info
[DT_STRTAB
])
921 + GL(dl_rtld_map
).l_info
[DT_SONAME
]->d_un
.d_val
,
922 (const char *) D_PTR (main_map
, l_info
[DT_STRTAB
])
923 + main_map
->l_info
[DT_SONAME
]->d_un
.d_val
) == 0)
924 _dl_fatal_printf ("loader cannot load itself\n");
926 phdr
= main_map
->l_phdr
;
927 phnum
= main_map
->l_phnum
;
928 /* We overwrite here a pointer to a malloc()ed string. But since
929 the malloc() implementation used at this point is the dummy
930 implementations which has no real free() function it does not
931 makes sense to free the old string first. */
932 main_map
->l_name
= (char *) "";
933 *user_entry
= main_map
->l_entry
;
935 #ifdef HAVE_AUX_VECTOR
936 /* Adjust the on-stack auxiliary vector so that it looks like the
937 binary was executed directly. */
938 for (ElfW(auxv_t
) *av
= auxv
; av
->a_type
!= AT_NULL
; av
++)
942 av
->a_un
.a_val
= (uintptr_t) phdr
;
945 av
->a_un
.a_val
= phnum
;
948 av
->a_un
.a_val
= *user_entry
;
951 av
->a_un
.a_val
= (uintptr_t) _dl_argv
[0];
958 /* Create a link_map for the executable itself.
959 This will be what dlopen on "" returns. */
960 main_map
= _dl_new_object ((char *) "", "", lt_executable
, NULL
,
961 __RTLD_OPENEXEC
, LM_ID_BASE
);
962 assert (main_map
!= NULL
);
963 main_map
->l_phdr
= phdr
;
964 main_map
->l_phnum
= phnum
;
965 main_map
->l_entry
= *user_entry
;
967 /* Even though the link map is not yet fully initialized we can add
968 it to the map list since there are no possible users running yet. */
969 _dl_add_to_namespace_list (main_map
, LM_ID_BASE
);
970 assert (main_map
== GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
);
972 /* At this point we are in a bit of trouble. We would have to
973 fill in the values for l_dev and l_ino. But in general we
974 do not know where the file is. We also do not handle AT_EXECFD
975 even if it would be passed up.
977 We leave the values here defined to 0. This is normally no
978 problem as the program code itself is normally no shared
979 object and therefore cannot be loaded dynamically. Nothing
980 prevent the use of dynamic binaries and in these situations
981 we might get problems. We might not be able to find out
982 whether the object is already loaded. But since there is no
983 easy way out and because the dynamic binary must also not
984 have an SONAME we ignore this program for now. If it becomes
985 a problem we can force people using SONAMEs. */
987 /* We delay initializing the path structure until we got the dynamic
988 information for the program. */
991 main_map
->l_map_end
= 0;
992 main_map
->l_text_end
= 0;
993 /* Perhaps the executable has no PT_LOAD header entries at all. */
994 main_map
->l_map_start
= ~0;
995 /* And it was opened directly. */
996 ++main_map
->l_direct_opencount
;
998 /* Scan the program header table for the dynamic section. */
999 for (ph
= phdr
; ph
< &phdr
[phnum
]; ++ph
)
1003 /* Find out the load address. */
1004 main_map
->l_addr
= (ElfW(Addr
)) phdr
- ph
->p_vaddr
;
1007 /* This tells us where to find the dynamic section,
1008 which tells us everything we need to do. */
1009 main_map
->l_ld
= (void *) main_map
->l_addr
+ ph
->p_vaddr
;
1012 /* This "interpreter segment" was used by the program loader to
1013 find the program interpreter, which is this program itself, the
1014 dynamic linker. We note what name finds us, so that a future
1015 dlopen call or DT_NEEDED entry, for something that wants to link
1016 against the dynamic linker as a shared library, will know that
1017 the shared object is already loaded. */
1018 _dl_rtld_libname
.name
= ((const char *) main_map
->l_addr
1020 /* _dl_rtld_libname.next = NULL; Already zero. */
1021 GL(dl_rtld_map
).l_libname
= &_dl_rtld_libname
;
1023 /* Ordinarilly, we would get additional names for the loader from
1024 our DT_SONAME. This can't happen if we were actually linked as
1025 a static executable (detect this case when we have no DYNAMIC).
1026 If so, assume the filename component of the interpreter path to
1027 be our SONAME, and add it to our name list. */
1028 if (GL(dl_rtld_map
).l_ld
== NULL
)
1030 const char *p
= NULL
;
1031 const char *cp
= _dl_rtld_libname
.name
;
1033 /* Find the filename part of the path. */
1040 _dl_rtld_libname2
.name
= p
;
1041 /* _dl_rtld_libname2.next = NULL; Already zero. */
1042 _dl_rtld_libname
.next
= &_dl_rtld_libname2
;
1050 ElfW(Addr
) mapstart
;
1051 ElfW(Addr
) allocend
;
1053 /* Remember where the main program starts in memory. */
1054 mapstart
= (main_map
->l_addr
1055 + (ph
->p_vaddr
& ~(GLRO(dl_pagesize
) - 1)));
1056 if (main_map
->l_map_start
> mapstart
)
1057 main_map
->l_map_start
= mapstart
;
1059 /* Also where it ends. */
1060 allocend
= main_map
->l_addr
+ ph
->p_vaddr
+ ph
->p_memsz
;
1061 if (main_map
->l_map_end
< allocend
)
1062 main_map
->l_map_end
= allocend
;
1063 if ((ph
->p_flags
& PF_X
) && allocend
> main_map
->l_text_end
)
1064 main_map
->l_text_end
= allocend
;
1069 if (ph
->p_memsz
> 0)
1071 /* Note that in the case the dynamic linker we duplicate work
1072 here since we read the PT_TLS entry already in
1073 _dl_start_final. But the result is repeatable so do not
1074 check for this special but unimportant case. */
1075 main_map
->l_tls_blocksize
= ph
->p_memsz
;
1076 main_map
->l_tls_align
= ph
->p_align
;
1077 if (ph
->p_align
== 0)
1078 main_map
->l_tls_firstbyte_offset
= 0;
1080 main_map
->l_tls_firstbyte_offset
= (ph
->p_vaddr
1081 & (ph
->p_align
- 1));
1082 main_map
->l_tls_initimage_size
= ph
->p_filesz
;
1083 main_map
->l_tls_initimage
= (void *) ph
->p_vaddr
;
1085 /* This image gets the ID one. */
1086 GL(dl_tls_max_dtv_idx
) = main_map
->l_tls_modid
= 1;
1091 GL(dl_stack_flags
) = ph
->p_flags
;
1095 main_map
->l_relro_addr
= ph
->p_vaddr
;
1096 main_map
->l_relro_size
= ph
->p_memsz
;
1100 /* Adjust the address of the TLS initialization image in case
1101 the executable is actually an ET_DYN object. */
1102 if (main_map
->l_tls_initimage
!= NULL
)
1103 main_map
->l_tls_initimage
1104 = (char *) main_map
->l_tls_initimage
+ main_map
->l_addr
;
1105 if (! main_map
->l_map_end
)
1106 main_map
->l_map_end
= ~0;
1107 if (! main_map
->l_text_end
)
1108 main_map
->l_text_end
= ~0;
1109 if (! GL(dl_rtld_map
).l_libname
&& GL(dl_rtld_map
).l_name
)
1111 /* We were invoked directly, so the program might not have a
1113 _dl_rtld_libname
.name
= GL(dl_rtld_map
).l_name
;
1114 /* _dl_rtld_libname.next = NULL; Already zero. */
1115 GL(dl_rtld_map
).l_libname
= &_dl_rtld_libname
;
1118 assert (GL(dl_rtld_map
).l_libname
); /* How else did we get here? */
1120 /* If the current libname is different from the SONAME, add the
1122 if (GL(dl_rtld_map
).l_info
[DT_SONAME
] != NULL
1123 && strcmp (GL(dl_rtld_map
).l_libname
->name
,
1124 (const char *) D_PTR (&GL(dl_rtld_map
), l_info
[DT_STRTAB
])
1125 + GL(dl_rtld_map
).l_info
[DT_SONAME
]->d_un
.d_val
) != 0)
1127 static struct libname_list newname
;
1128 newname
.name
= ((char *) D_PTR (&GL(dl_rtld_map
), l_info
[DT_STRTAB
])
1129 + GL(dl_rtld_map
).l_info
[DT_SONAME
]->d_un
.d_ptr
);
1130 newname
.next
= NULL
;
1131 newname
.dont_free
= 1;
1133 assert (GL(dl_rtld_map
).l_libname
->next
== NULL
);
1134 GL(dl_rtld_map
).l_libname
->next
= &newname
;
1136 /* The ld.so must be relocated since otherwise loading audit modules
1137 will fail since they reuse the very same ld.so. */
1138 assert (GL(dl_rtld_map
).l_relocated
);
1142 /* Extract the contents of the dynamic section for easy access. */
1143 elf_get_dynamic_info (main_map
, NULL
);
1144 /* Set up our cache of pointers into the hash table. */
1145 _dl_setup_hash (main_map
);
1148 if (__builtin_expect (mode
, normal
) == verify
)
1150 /* We were called just to verify that this is a dynamic
1151 executable using us as the program interpreter. Exit with an
1152 error if we were not able to load the binary or no interpreter
1153 is specified (i.e., this is no dynamically linked binary. */
1154 if (main_map
->l_ld
== NULL
)
1157 /* We allow here some platform specific code. */
1158 #ifdef DISTINGUISH_LIB_VERSIONS
1159 DISTINGUISH_LIB_VERSIONS
;
1161 _exit (has_interp
? 0 : 2);
1164 struct link_map
**first_preload
= &GL(dl_rtld_map
).l_next
;
1165 /* Set up the data structures for the system-supplied DSO early,
1166 so they can influence _dl_init_paths. */
1167 setup_vdso (main_map
, &first_preload
);
1169 #ifdef DL_SYSDEP_OSCHECK
1170 DL_SYSDEP_OSCHECK (_dl_fatal_printf
);
1173 /* Initialize the data structures for the search paths for shared
1175 _dl_init_paths (library_path
);
1177 /* Initialize _r_debug. */
1178 struct r_debug
*r
= _dl_debug_initialize (GL(dl_rtld_map
).l_addr
,
1180 r
->r_state
= RT_CONSISTENT
;
1182 /* Put the link_map for ourselves on the chain so it can be found by
1183 name. Note that at this point the global chain of link maps contains
1184 exactly one element, which is pointed to by dl_loaded. */
1185 if (! GL(dl_rtld_map
).l_name
)
1186 /* If not invoked directly, the dynamic linker shared object file was
1187 found by the PT_INTERP name. */
1188 GL(dl_rtld_map
).l_name
= (char *) GL(dl_rtld_map
).l_libname
->name
;
1189 GL(dl_rtld_map
).l_type
= lt_library
;
1190 main_map
->l_next
= &GL(dl_rtld_map
);
1191 GL(dl_rtld_map
).l_prev
= main_map
;
1192 ++GL(dl_ns
)[LM_ID_BASE
]._ns_nloaded
;
1195 /* If LD_USE_LOAD_BIAS env variable has not been seen, default
1196 to not using bias for non-prelinked PIEs and libraries
1197 and using it for executables or prelinked PIEs or libraries. */
1198 if (GLRO(dl_use_load_bias
) == (ElfW(Addr
)) -2)
1199 GLRO(dl_use_load_bias
) = main_map
->l_addr
== 0 ? -1 : 0;
1201 /* Set up the program header information for the dynamic linker
1202 itself. It is needed in the dl_iterate_phdr callbacks. */
1203 const ElfW(Ehdr
) *rtld_ehdr
;
1205 /* Starting from binutils-2.23, the linker will define the magic symbol
1206 __ehdr_start to point to our own ELF header if it is visible in a
1207 segment that also includes the phdrs. If that's not available, we use
1208 the old method that assumes the beginning of the file is part of the
1209 lowest-addressed PT_LOAD segment. */
1210 #ifdef HAVE_EHDR_START
1211 extern const ElfW(Ehdr
) __ehdr_start
__attribute__ ((visibility ("hidden")));
1212 rtld_ehdr
= &__ehdr_start
;
1214 rtld_ehdr
= (void *) GL(dl_rtld_map
).l_map_start
;
1216 assert (rtld_ehdr
->e_ehsize
== sizeof *rtld_ehdr
);
1217 assert (rtld_ehdr
->e_phentsize
== sizeof (ElfW(Phdr
)));
1219 const ElfW(Phdr
) *rtld_phdr
= (const void *) rtld_ehdr
+ rtld_ehdr
->e_phoff
;
1221 GL(dl_rtld_map
).l_phdr
= rtld_phdr
;
1222 GL(dl_rtld_map
).l_phnum
= rtld_ehdr
->e_phnum
;
1225 /* PT_GNU_RELRO is usually the last phdr. */
1226 size_t cnt
= rtld_ehdr
->e_phnum
;
1228 if (rtld_phdr
[cnt
].p_type
== PT_GNU_RELRO
)
1230 GL(dl_rtld_map
).l_relro_addr
= rtld_phdr
[cnt
].p_vaddr
;
1231 GL(dl_rtld_map
).l_relro_size
= rtld_phdr
[cnt
].p_memsz
;
1235 /* Add the dynamic linker to the TLS list if it also uses TLS. */
1236 if (GL(dl_rtld_map
).l_tls_blocksize
!= 0)
1237 /* Assign a module ID. Do this before loading any audit modules. */
1238 GL(dl_rtld_map
).l_tls_modid
= _dl_next_tls_modid ();
1240 /* If we have auditing DSOs to load, do it now. */
1241 if (__glibc_unlikely (audit_list
!= NULL
))
1243 /* Iterate over all entries in the list. The order is important. */
1244 struct audit_ifaces
*last_audit
= NULL
;
1245 struct audit_list
*al
= audit_list
->next
;
1247 /* Since we start using the auditing DSOs right away we need to
1248 initialize the data structures now. */
1251 /* Initialize security features. We need to do it this early
1252 since otherwise the constructors of the audit libraries will
1253 use different values (especially the pointer guard) and will
1259 int tls_idx
= GL(dl_tls_max_dtv_idx
);
1261 /* Now it is time to determine the layout of the static TLS
1262 block and allocate it for the initial thread. Note that we
1263 always allocate the static block, we never defer it even if
1264 no DF_STATIC_TLS bit is set. The reason is that we know
1265 glibc will use the static model. */
1266 struct dlmopen_args dlmargs
;
1267 dlmargs
.fname
= al
->name
;
1270 const char *objname
;
1271 const char *err_str
= NULL
;
1273 (void) _dl_catch_error (&objname
, &err_str
, &malloced
, dlmopen_doit
,
1275 if (__glibc_unlikely (err_str
!= NULL
))
1278 _dl_error_printf ("\
1279 ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
1282 free ((char *) err_str
);
1286 struct lookup_args largs
;
1287 largs
.name
= "la_version";
1288 largs
.map
= dlmargs
.map
;
1290 /* Check whether the interface version matches. */
1291 (void) _dl_catch_error (&objname
, &err_str
, &malloced
,
1292 lookup_doit
, &largs
);
1294 unsigned int (*laversion
) (unsigned int);
1297 && (laversion
= largs
.result
) != NULL
1298 && (lav
= laversion (LAV_CURRENT
)) > 0
1299 && lav
<= LAV_CURRENT
)
1301 /* Allocate structure for the callback function pointers.
1302 This call can never fail. */
1305 struct audit_ifaces ifaces
;
1306 #define naudit_ifaces 8
1307 void (*fptr
[naudit_ifaces
]) (void);
1308 } *newp
= malloc (sizeof (*newp
));
1310 /* Names of the auditing interfaces. All in one
1312 static const char audit_iface_names
[] =
1317 #if __ELF_NATIVE_CLASS == 32
1319 #elif __ELF_NATIVE_CLASS == 64
1322 # error "__ELF_NATIVE_CLASS must be defined"
1324 #define STRING(s) __STRING (s)
1325 "la_" STRING (ARCH_LA_PLTENTER
) "\0"
1326 "la_" STRING (ARCH_LA_PLTEXIT
) "\0"
1328 unsigned int cnt
= 0;
1329 const char *cp
= audit_iface_names
;
1333 (void) _dl_catch_error (&objname
, &err_str
, &malloced
,
1334 lookup_doit
, &largs
);
1336 /* Store the pointer. */
1337 if (err_str
== NULL
&& largs
.result
!= NULL
)
1339 newp
->fptr
[cnt
] = largs
.result
;
1341 /* The dynamic linker link map is statically
1342 allocated, initialize the data now. */
1343 GL(dl_rtld_map
).l_audit
[cnt
].cookie
1344 = (intptr_t) &GL(dl_rtld_map
);
1347 newp
->fptr
[cnt
] = NULL
;
1350 cp
= (char *) rawmemchr (cp
, '\0') + 1;
1352 while (*cp
!= '\0');
1353 assert (cnt
== naudit_ifaces
);
1355 /* Now append the new auditing interface to the list. */
1356 newp
->ifaces
.next
= NULL
;
1357 if (last_audit
== NULL
)
1358 last_audit
= GLRO(dl_audit
) = &newp
->ifaces
;
1360 last_audit
= last_audit
->next
= &newp
->ifaces
;
1363 /* Mark the DSO as being used for auditing. */
1364 dlmargs
.map
->l_auditing
= 1;
1368 /* We cannot use the DSO, it does not have the
1369 appropriate interfaces or it expects something
1372 Lmid_t ns
= dlmargs
.map
->l_ns
;
1374 _dl_close (dlmargs
.map
);
1376 /* Make sure the namespace has been cleared entirely. */
1377 assert (GL(dl_ns
)[ns
]._ns_loaded
== NULL
);
1378 assert (GL(dl_ns
)[ns
]._ns_nloaded
== 0);
1380 GL(dl_tls_max_dtv_idx
) = tls_idx
;
1387 while (al
!= audit_list
->next
);
1389 /* If we have any auditing modules, announce that we already
1390 have two objects loaded. */
1391 if (__glibc_unlikely (GLRO(dl_naudit
) > 0))
1393 struct link_map
*ls
[2] = { main_map
, &GL(dl_rtld_map
) };
1395 for (unsigned int outer
= 0; outer
< 2; ++outer
)
1397 struct audit_ifaces
*afct
= GLRO(dl_audit
);
1398 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
1400 if (afct
->objopen
!= NULL
)
1402 ls
[outer
]->l_audit
[cnt
].bindflags
1403 = afct
->objopen (ls
[outer
], LM_ID_BASE
,
1404 &ls
[outer
]->l_audit
[cnt
].cookie
);
1406 ls
[outer
]->l_audit_any_plt
1407 |= ls
[outer
]->l_audit
[cnt
].bindflags
!= 0;
1416 /* Keep track of the currently loaded modules to count how many
1417 non-audit modules which use TLS are loaded. */
1418 size_t count_modids
= _dl_count_modids ();
1420 /* Set up debugging before the debugger is notified for the first time. */
1421 #ifdef ELF_MACHINE_DEBUG_SETUP
1422 /* Some machines (e.g. MIPS) don't use DT_DEBUG in this way. */
1423 ELF_MACHINE_DEBUG_SETUP (main_map
, r
);
1424 ELF_MACHINE_DEBUG_SETUP (&GL(dl_rtld_map
), r
);
1426 if (main_map
->l_info
[DT_DEBUG
] != NULL
)
1427 /* There is a DT_DEBUG entry in the dynamic section. Fill it in
1428 with the run-time address of the r_debug structure */
1429 main_map
->l_info
[DT_DEBUG
]->d_un
.d_ptr
= (ElfW(Addr
)) r
;
1431 /* Fill in the pointer in the dynamic linker's own dynamic section, in
1432 case you run gdb on the dynamic linker directly. */
1433 if (GL(dl_rtld_map
).l_info
[DT_DEBUG
] != NULL
)
1434 GL(dl_rtld_map
).l_info
[DT_DEBUG
]->d_un
.d_ptr
= (ElfW(Addr
)) r
;
1437 /* We start adding objects. */
1438 r
->r_state
= RT_ADD
;
1440 LIBC_PROBE (init_start
, 2, LM_ID_BASE
, r
);
1442 /* Auditing checkpoint: we are ready to signal that the initial map
1443 is being constructed. */
1444 if (__glibc_unlikely (GLRO(dl_naudit
) > 0))
1446 struct audit_ifaces
*afct
= GLRO(dl_audit
);
1447 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
1449 if (afct
->activity
!= NULL
)
1450 afct
->activity (&main_map
->l_audit
[cnt
].cookie
, LA_ACT_ADD
);
1456 /* We have two ways to specify objects to preload: via environment
1457 variable and via the file /etc/ld.so.preload. The latter can also
1458 be used when security is enabled. */
1459 assert (*first_preload
== NULL
);
1460 struct link_map
**preloads
= NULL
;
1461 unsigned int npreloads
= 0;
1463 if (__glibc_unlikely (preloadlist
!= NULL
))
1465 /* The LD_PRELOAD environment variable gives list of libraries
1466 separated by white space or colons that are loaded before the
1467 executable's dependencies and prepended to the global scope
1468 list. If the binary is running setuid all elements
1469 containing a '/' are ignored since it is insecure. */
1470 char *list
= strdupa (preloadlist
);
1473 HP_TIMING_NOW (start
);
1475 /* Prevent optimizing strsep. Speed is not important here. */
1476 while ((p
= (strsep
) (&list
, " :")) != NULL
)
1478 && (__builtin_expect (! __libc_enable_secure
, 1)
1479 || strchr (p
, '/') == NULL
))
1480 npreloads
+= do_preload (p
, main_map
, "LD_PRELOAD");
1482 HP_TIMING_NOW (stop
);
1483 HP_TIMING_DIFF (diff
, start
, stop
);
1484 HP_TIMING_ACCUM_NT (load_time
, diff
);
1487 /* There usually is no ld.so.preload file, it should only be used
1488 for emergencies and testing. So the open call etc should usually
1489 fail. Using access() on a non-existing file is faster than using
1490 open(). So we do this first. If it succeeds we do almost twice
1491 the work but this does not matter, since it is not for production
1493 static const char preload_file
[] = "/etc/ld.so.preload";
1494 if (__glibc_unlikely (__access (preload_file
, R_OK
) == 0))
1496 /* Read the contents of the file. */
1497 file
= _dl_sysdep_read_whole_file (preload_file
, &file_size
,
1498 PROT_READ
| PROT_WRITE
);
1499 if (__glibc_unlikely (file
!= MAP_FAILED
))
1501 /* Parse the file. It contains names of libraries to be loaded,
1502 separated by white spaces or `:'. It may also contain
1503 comments introduced by `#'. */
1508 /* Eliminate comments. */
1513 char *comment
= memchr (runp
, '#', rest
);
1514 if (comment
== NULL
)
1517 rest
-= comment
- runp
;
1520 while (--rest
> 0 && *++comment
!= '\n');
1523 /* We have one problematic case: if we have a name at the end of
1524 the file without a trailing terminating characters, we cannot
1525 place the \0. Handle the case separately. */
1526 if (file
[file_size
- 1] != ' ' && file
[file_size
- 1] != '\t'
1527 && file
[file_size
- 1] != '\n' && file
[file_size
- 1] != ':')
1529 problem
= &file
[file_size
];
1530 while (problem
> file
&& problem
[-1] != ' '
1531 && problem
[-1] != '\t'
1532 && problem
[-1] != '\n' && problem
[-1] != ':')
1541 file
[file_size
- 1] = '\0';
1544 HP_TIMING_NOW (start
);
1546 if (file
!= problem
)
1550 while ((p
= strsep (&runp
, ": \t\n")) != NULL
)
1552 npreloads
+= do_preload (p
, main_map
, preload_file
);
1555 if (problem
!= NULL
)
1557 char *p
= strndupa (problem
, file_size
- (problem
- file
));
1559 npreloads
+= do_preload (p
, main_map
, preload_file
);
1562 HP_TIMING_NOW (stop
);
1563 HP_TIMING_DIFF (diff
, start
, stop
);
1564 HP_TIMING_ACCUM_NT (load_time
, diff
);
1566 /* We don't need the file anymore. */
1567 __munmap (file
, file_size
);
1571 if (__glibc_unlikely (*first_preload
!= NULL
))
1573 /* Set up PRELOADS with a vector of the preloaded libraries. */
1574 struct link_map
*l
= *first_preload
;
1575 preloads
= __alloca (npreloads
* sizeof preloads
[0]);
1582 assert (i
== npreloads
);
1585 /* Load all the libraries specified by DT_NEEDED entries. If LD_PRELOAD
1586 specified some libraries to load, these are inserted before the actual
1587 dependencies in the executable's searchlist for symbol resolution. */
1588 HP_TIMING_NOW (start
);
1589 _dl_map_object_deps (main_map
, preloads
, npreloads
, mode
== trace
, 0);
1590 HP_TIMING_NOW (stop
);
1591 HP_TIMING_DIFF (diff
, start
, stop
);
1592 HP_TIMING_ACCUM_NT (load_time
, diff
);
1594 /* Mark all objects as being in the global scope. */
1595 for (i
= main_map
->l_searchlist
.r_nlist
; i
> 0; )
1596 main_map
->l_searchlist
.r_list
[--i
]->l_global
= 1;
1598 /* Remove _dl_rtld_map from the chain. */
1599 GL(dl_rtld_map
).l_prev
->l_next
= GL(dl_rtld_map
).l_next
;
1600 if (GL(dl_rtld_map
).l_next
!= NULL
)
1601 GL(dl_rtld_map
).l_next
->l_prev
= GL(dl_rtld_map
).l_prev
;
1603 for (i
= 1; i
< main_map
->l_searchlist
.r_nlist
; ++i
)
1604 if (main_map
->l_searchlist
.r_list
[i
] == &GL(dl_rtld_map
))
1607 bool rtld_multiple_ref
= false;
1608 if (__glibc_likely (i
< main_map
->l_searchlist
.r_nlist
))
1610 /* Some DT_NEEDED entry referred to the interpreter object itself, so
1611 put it back in the list of visible objects. We insert it into the
1612 chain in symbol search order because gdb uses the chain's order as
1613 its symbol search order. */
1614 rtld_multiple_ref
= true;
1616 GL(dl_rtld_map
).l_prev
= main_map
->l_searchlist
.r_list
[i
- 1];
1617 if (__builtin_expect (mode
, normal
) == normal
)
1619 GL(dl_rtld_map
).l_next
= (i
+ 1 < main_map
->l_searchlist
.r_nlist
1620 ? main_map
->l_searchlist
.r_list
[i
+ 1]
1622 #ifdef NEED_DL_SYSINFO_DSO
1623 if (GLRO(dl_sysinfo_map
) != NULL
1624 && GL(dl_rtld_map
).l_prev
->l_next
== GLRO(dl_sysinfo_map
)
1625 && GL(dl_rtld_map
).l_next
!= GLRO(dl_sysinfo_map
))
1626 GL(dl_rtld_map
).l_prev
= GLRO(dl_sysinfo_map
);
1630 /* In trace mode there might be an invisible object (which we
1631 could not find) after the previous one in the search list.
1632 In this case it doesn't matter much where we put the
1633 interpreter object, so we just initialize the list pointer so
1634 that the assertion below holds. */
1635 GL(dl_rtld_map
).l_next
= GL(dl_rtld_map
).l_prev
->l_next
;
1637 assert (GL(dl_rtld_map
).l_prev
->l_next
== GL(dl_rtld_map
).l_next
);
1638 GL(dl_rtld_map
).l_prev
->l_next
= &GL(dl_rtld_map
);
1639 if (GL(dl_rtld_map
).l_next
!= NULL
)
1641 assert (GL(dl_rtld_map
).l_next
->l_prev
== GL(dl_rtld_map
).l_prev
);
1642 GL(dl_rtld_map
).l_next
->l_prev
= &GL(dl_rtld_map
);
1646 /* Now let us see whether all libraries are available in the
1647 versions we need. */
1649 struct version_check_args args
;
1650 args
.doexit
= mode
== normal
;
1651 args
.dotrace
= mode
== trace
;
1652 _dl_receive_error (print_missing_version
, version_check_doit
, &args
);
1655 /* We do not initialize any of the TLS functionality unless any of the
1656 initial modules uses TLS. This makes dynamic loading of modules with
1657 TLS impossible, but to support it requires either eagerly doing setup
1658 now or lazily doing it later. Doing it now makes us incompatible with
1659 an old kernel that can't perform TLS_INIT_TP, even if no TLS is ever
1660 used. Trying to do it lazily is too hairy to try when there could be
1661 multiple threads (from a non-TLS-using libpthread). */
1662 bool was_tls_init_tp_called
= tls_init_tp_called
;
1666 if (__glibc_likely (audit_list
== NULL
))
1667 /* Initialize security features. But only if we have not done it
1671 if (__builtin_expect (mode
, normal
) != normal
)
1673 /* We were run just to list the shared libraries. It is
1674 important that we do this before real relocation, because the
1675 functions we call below for output may no longer work properly
1676 after relocation. */
1679 if (GLRO(dl_debug_mask
) & DL_DEBUG_PRELINK
)
1681 struct r_scope_elem
*scope
= &main_map
->l_searchlist
;
1683 for (i
= 0; i
< scope
->r_nlist
; i
++)
1685 l
= scope
->r_list
[i
];
1688 _dl_printf ("\t%s => not found\n", l
->l_libname
->name
);
1691 if (_dl_name_match_p (GLRO(dl_trace_prelink
), l
))
1692 GLRO(dl_trace_prelink_map
) = l
;
1693 _dl_printf ("\t%s => %s (0x%0*Zx, 0x%0*Zx)",
1694 DSO_FILENAME (l
->l_libname
->name
),
1695 DSO_FILENAME (l
->l_name
),
1696 (int) sizeof l
->l_map_start
* 2,
1697 (size_t) l
->l_map_start
,
1698 (int) sizeof l
->l_addr
* 2,
1699 (size_t) l
->l_addr
);
1702 _dl_printf (" TLS(0x%Zx, 0x%0*Zx)\n", l
->l_tls_modid
,
1703 (int) sizeof l
->l_tls_offset
* 2,
1704 (size_t) l
->l_tls_offset
);
1709 else if (GLRO(dl_debug_mask
) & DL_DEBUG_UNUSED
)
1711 /* Look through the dependencies of the main executable
1712 and determine which of them is not actually
1714 struct link_map
*l
= main_map
;
1716 /* Relocate the main executable. */
1717 struct relocate_args args
= { .l
= l
,
1718 .reloc_mode
= ((GLRO(dl_lazy
)
1720 | __RTLD_NOIFUNC
) };
1721 _dl_receive_error (print_unresolved
, relocate_doit
, &args
);
1723 /* This loop depends on the dependencies of the executable to
1724 correspond in number and order to the DT_NEEDED entries. */
1725 ElfW(Dyn
) *dyn
= main_map
->l_ld
;
1727 while (dyn
->d_tag
!= DT_NULL
)
1729 if (dyn
->d_tag
== DT_NEEDED
)
1732 #ifdef NEED_DL_SYSINFO_DSO
1733 /* Skip the VDSO since it's not part of the list
1734 of objects we brought in via DT_NEEDED entries. */
1735 if (l
== GLRO(dl_sysinfo_map
))
1742 _dl_printf ("Unused direct dependencies:\n");
1746 _dl_printf ("\t%s\n", l
->l_name
);
1753 _exit (first
!= true);
1755 else if (! main_map
->l_info
[DT_NEEDED
])
1756 _dl_printf ("\tstatically linked\n");
1759 for (l
= main_map
->l_next
; l
; l
= l
->l_next
)
1761 /* The library was not found. */
1762 _dl_printf ("\t%s => not found\n", l
->l_libname
->name
);
1763 else if (strcmp (l
->l_libname
->name
, l
->l_name
) == 0)
1764 _dl_printf ("\t%s (0x%0*Zx)\n", l
->l_libname
->name
,
1765 (int) sizeof l
->l_map_start
* 2,
1766 (size_t) l
->l_map_start
);
1768 _dl_printf ("\t%s => %s (0x%0*Zx)\n", l
->l_libname
->name
,
1769 l
->l_name
, (int) sizeof l
->l_map_start
* 2,
1770 (size_t) l
->l_map_start
);
1773 if (__builtin_expect (mode
, trace
) != trace
)
1774 for (i
= 1; i
< (unsigned int) _dl_argc
; ++i
)
1776 const ElfW(Sym
) *ref
= NULL
;
1777 ElfW(Addr
) loadbase
;
1780 result
= _dl_lookup_symbol_x (_dl_argv
[i
], main_map
,
1781 &ref
, main_map
->l_scope
,
1782 NULL
, ELF_RTYPE_CLASS_PLT
,
1783 DL_LOOKUP_ADD_DEPENDENCY
, NULL
);
1785 loadbase
= LOOKUP_VALUE_ADDRESS (result
);
1787 _dl_printf ("%s found at 0x%0*Zd in object at 0x%0*Zd\n",
1789 (int) sizeof ref
->st_value
* 2,
1790 (size_t) ref
->st_value
,
1791 (int) sizeof loadbase
* 2, (size_t) loadbase
);
1795 /* If LD_WARN is set, warn about undefined symbols. */
1796 if (GLRO(dl_lazy
) >= 0 && GLRO(dl_verbose
))
1798 /* We have to do symbol dependency testing. */
1799 struct relocate_args args
;
1802 args
.reloc_mode
= ((GLRO(dl_lazy
) ? RTLD_LAZY
: 0)
1805 i
= main_map
->l_searchlist
.r_nlist
;
1808 struct link_map
*l
= main_map
->l_initfini
[i
];
1809 if (l
!= &GL(dl_rtld_map
) && ! l
->l_faked
)
1812 _dl_receive_error (print_unresolved
, relocate_doit
,
1817 if ((GLRO(dl_debug_mask
) & DL_DEBUG_PRELINK
)
1818 && rtld_multiple_ref
)
1820 /* Mark the link map as not yet relocated again. */
1821 GL(dl_rtld_map
).l_relocated
= 0;
1822 _dl_relocate_object (&GL(dl_rtld_map
),
1823 main_map
->l_scope
, __RTLD_NOIFUNC
, 0);
1826 #define VERNEEDTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERNEED))
1829 /* Print more information. This means here, print information
1830 about the versions needed. */
1832 struct link_map
*map
;
1834 for (map
= main_map
; map
!= NULL
; map
= map
->l_next
)
1837 ElfW(Dyn
) *dyn
= map
->l_info
[VERNEEDTAG
];
1843 strtab
= (const void *) D_PTR (map
, l_info
[DT_STRTAB
]);
1844 ent
= (ElfW(Verneed
) *) (map
->l_addr
+ dyn
->d_un
.d_ptr
);
1848 _dl_printf ("\n\tVersion information:\n");
1852 _dl_printf ("\t%s:\n", DSO_FILENAME (map
->l_name
));
1857 struct link_map
*needed
;
1859 needed
= find_needed (strtab
+ ent
->vn_file
);
1860 aux
= (ElfW(Vernaux
) *) ((char *) ent
+ ent
->vn_aux
);
1864 const char *fname
= NULL
;
1867 && match_version (strtab
+ aux
->vna_name
,
1869 fname
= needed
->l_name
;
1871 _dl_printf ("\t\t%s (%s) %s=> %s\n",
1872 strtab
+ ent
->vn_file
,
1873 strtab
+ aux
->vna_name
,
1874 aux
->vna_flags
& VER_FLG_WEAK
1876 fname
?: "not found");
1878 if (aux
->vna_next
== 0)
1879 /* No more symbols. */
1883 aux
= (ElfW(Vernaux
) *) ((char *) aux
1887 if (ent
->vn_next
== 0)
1888 /* No more dependencies. */
1891 /* Next dependency. */
1892 ent
= (ElfW(Verneed
) *) ((char *) ent
+ ent
->vn_next
);
1901 if (main_map
->l_info
[ADDRIDX (DT_GNU_LIBLIST
)]
1902 && ! __builtin_expect (GLRO(dl_profile
) != NULL
, 0)
1903 && ! __builtin_expect (GLRO(dl_dynamic_weak
), 0))
1905 ElfW(Lib
) *liblist
, *liblistend
;
1906 struct link_map
**r_list
, **r_listend
, *l
;
1907 const char *strtab
= (const void *) D_PTR (main_map
, l_info
[DT_STRTAB
]);
1909 assert (main_map
->l_info
[VALIDX (DT_GNU_LIBLISTSZ
)] != NULL
);
1910 liblist
= (ElfW(Lib
) *)
1911 main_map
->l_info
[ADDRIDX (DT_GNU_LIBLIST
)]->d_un
.d_ptr
;
1912 liblistend
= (ElfW(Lib
) *)
1914 main_map
->l_info
[VALIDX (DT_GNU_LIBLISTSZ
)]->d_un
.d_val
);
1915 r_list
= main_map
->l_searchlist
.r_list
;
1916 r_listend
= r_list
+ main_map
->l_searchlist
.r_nlist
;
1918 for (; r_list
< r_listend
&& liblist
< liblistend
; r_list
++)
1925 /* If the library is not mapped where it should, fail. */
1929 /* Next, check if checksum matches. */
1930 if (l
->l_info
[VALIDX(DT_CHECKSUM
)] == NULL
1931 || l
->l_info
[VALIDX(DT_CHECKSUM
)]->d_un
.d_val
1932 != liblist
->l_checksum
)
1935 if (l
->l_info
[VALIDX(DT_GNU_PRELINKED
)] == NULL
1936 || l
->l_info
[VALIDX(DT_GNU_PRELINKED
)]->d_un
.d_val
1937 != liblist
->l_time_stamp
)
1940 if (! _dl_name_match_p (strtab
+ liblist
->l_name
, l
))
1947 if (r_list
== r_listend
&& liblist
== liblistend
)
1950 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_LIBS
))
1951 _dl_debug_printf ("\nprelink checking: %s\n",
1952 prelinked
? "ok" : "failed");
1956 /* Now set up the variable which helps the assembler startup code. */
1957 GL(dl_ns
)[LM_ID_BASE
]._ns_main_searchlist
= &main_map
->l_searchlist
;
1959 /* Save the information about the original global scope list since
1960 we need it in the memory handling later. */
1961 GLRO(dl_initial_searchlist
) = *GL(dl_ns
)[LM_ID_BASE
]._ns_main_searchlist
;
1963 /* Remember the last search directory added at startup, now that
1964 malloc will no longer be the one from dl-minimal.c. */
1965 GLRO(dl_init_all_dirs
) = GL(dl_all_dirs
);
1967 /* Print scope information. */
1968 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_SCOPES
))
1970 _dl_debug_printf ("\nInitial object scopes\n");
1972 for (struct link_map
*l
= main_map
; l
!= NULL
; l
= l
->l_next
)
1973 _dl_show_scope (l
, 0);
1978 if (main_map
->l_info
[ADDRIDX (DT_GNU_CONFLICT
)] != NULL
)
1980 ElfW(Rela
) *conflict
, *conflictend
;
1981 #ifndef HP_TIMING_NONAVAIL
1986 HP_TIMING_NOW (start
);
1987 assert (main_map
->l_info
[VALIDX (DT_GNU_CONFLICTSZ
)] != NULL
);
1988 conflict
= (ElfW(Rela
) *)
1989 main_map
->l_info
[ADDRIDX (DT_GNU_CONFLICT
)]->d_un
.d_ptr
;
1990 conflictend
= (ElfW(Rela
) *)
1992 + main_map
->l_info
[VALIDX (DT_GNU_CONFLICTSZ
)]->d_un
.d_val
);
1993 _dl_resolve_conflicts (main_map
, conflict
, conflictend
);
1994 HP_TIMING_NOW (stop
);
1995 HP_TIMING_DIFF (relocate_time
, start
, stop
);
1999 /* Mark all the objects so we know they have been already relocated. */
2000 for (struct link_map
*l
= main_map
; l
!= NULL
; l
= l
->l_next
)
2003 if (l
->l_relro_size
)
2004 _dl_protect_relro (l
);
2006 /* Add object to slot information data if necessasy. */
2007 if (l
->l_tls_blocksize
!= 0 && tls_init_tp_called
)
2008 _dl_add_to_slotinfo (l
);
2013 /* Now we have all the objects loaded. Relocate them all except for
2014 the dynamic linker itself. We do this in reverse order so that copy
2015 relocs of earlier objects overwrite the data written by later
2016 objects. We do not re-relocate the dynamic linker itself in this
2017 loop because that could result in the GOT entries for functions we
2018 call being changed, and that would break us. It is safe to relocate
2019 the dynamic linker out of order because it has no copy relocs (we
2020 know that because it is self-contained). */
2022 int consider_profiling
= GLRO(dl_profile
) != NULL
;
2023 #ifndef HP_TIMING_NONAVAIL
2028 /* If we are profiling we also must do lazy reloaction. */
2029 GLRO(dl_lazy
) |= consider_profiling
;
2031 HP_TIMING_NOW (start
);
2032 unsigned i
= main_map
->l_searchlist
.r_nlist
;
2035 struct link_map
*l
= main_map
->l_initfini
[i
];
2037 /* While we are at it, help the memory handling a bit. We have to
2038 mark some data structures as allocated with the fake malloc()
2039 implementation in ld.so. */
2040 struct libname_list
*lnp
= l
->l_libname
->next
;
2042 while (__builtin_expect (lnp
!= NULL
, 0))
2047 /* Also allocated with the fake malloc(). */
2048 l
->l_free_initfini
= 0;
2050 if (l
!= &GL(dl_rtld_map
))
2051 _dl_relocate_object (l
, l
->l_scope
, GLRO(dl_lazy
) ? RTLD_LAZY
: 0,
2052 consider_profiling
);
2054 /* Add object to slot information data if necessasy. */
2055 if (l
->l_tls_blocksize
!= 0 && tls_init_tp_called
)
2056 _dl_add_to_slotinfo (l
);
2058 HP_TIMING_NOW (stop
);
2060 HP_TIMING_DIFF (relocate_time
, start
, stop
);
2062 /* Now enable profiling if needed. Like the previous call,
2063 this has to go here because the calls it makes should use the
2064 rtld versions of the functions (particularly calloc()), but it
2065 needs to have _dl_profile_map set up by the relocator. */
2066 if (__glibc_unlikely (GL(dl_profile_map
) != NULL
))
2067 /* We must prepare the profiling. */
2068 _dl_start_profile ();
2071 if ((!was_tls_init_tp_called
&& GL(dl_tls_max_dtv_idx
) > 0)
2072 || count_modids
!= _dl_count_modids ())
2073 ++GL(dl_tls_generation
);
2075 /* Now that we have completed relocation, the initializer data
2076 for the TLS blocks has its final values and we can copy them
2077 into the main thread's TLS area, which we allocated above. */
2078 _dl_allocate_tls_init (tcbp
);
2080 /* And finally install it for the main thread. */
2081 if (! tls_init_tp_called
)
2083 const char *lossage
= TLS_INIT_TP (tcbp
);
2084 if (__glibc_unlikely (lossage
!= NULL
))
2085 _dl_fatal_printf ("cannot set up thread-local storage: %s\n",
2089 /* Make sure no new search directories have been added. */
2090 assert (GLRO(dl_init_all_dirs
) == GL(dl_all_dirs
));
2092 if (! prelinked
&& rtld_multiple_ref
)
2094 /* There was an explicit ref to the dynamic linker as a shared lib.
2095 Re-relocate ourselves with user-controlled symbol definitions.
2097 We must do this after TLS initialization in case after this
2098 re-relocation, we might call a user-supplied function
2099 (e.g. calloc from _dl_relocate_object) that uses TLS data. */
2101 #ifndef HP_TIMING_NONAVAIL
2107 HP_TIMING_NOW (start
);
2108 /* Mark the link map as not yet relocated again. */
2109 GL(dl_rtld_map
).l_relocated
= 0;
2110 _dl_relocate_object (&GL(dl_rtld_map
), main_map
->l_scope
, 0, 0);
2111 HP_TIMING_NOW (stop
);
2112 HP_TIMING_DIFF (add
, start
, stop
);
2113 HP_TIMING_ACCUM_NT (relocate_time
, add
);
2116 /* Do any necessary cleanups for the startup OS interface code.
2117 We do these now so that no calls are made after rtld re-relocation
2118 which might be resolved to different functions than we expect.
2119 We cannot do this before relocating the other objects because
2120 _dl_relocate_object might need to call `mprotect' for DT_TEXTREL. */
2121 _dl_sysdep_start_cleanup ();
2124 /* Auditing checkpoint: we have added all objects. */
2125 if (__glibc_unlikely (GLRO(dl_naudit
) > 0))
2127 struct link_map
*head
= GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
;
2128 /* Do not call the functions for any auditing object. */
2129 if (head
->l_auditing
== 0)
2131 struct audit_ifaces
*afct
= GLRO(dl_audit
);
2132 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
2134 if (afct
->activity
!= NULL
)
2135 afct
->activity (&head
->l_audit
[cnt
].cookie
, LA_ACT_CONSISTENT
);
2143 /* Notify the debugger all new objects are now ready to go. We must re-get
2144 the address since by now the variable might be in another object. */
2145 r
= _dl_debug_initialize (0, LM_ID_BASE
);
2146 r
->r_state
= RT_CONSISTENT
;
2148 LIBC_PROBE (init_complete
, 2, LM_ID_BASE
, r
);
2150 #if defined USE_LDCONFIG && !defined MAP_COPY
2151 /* We must munmap() the cache file. */
2152 _dl_unload_cache ();
2155 /* Once we return, _dl_sysdep_start will invoke
2156 the DT_INIT functions and then *USER_ENTRY. */
2159 /* This is a little helper function for resolving symbols while
2160 tracing the binary. */
2162 print_unresolved (int errcode
__attribute__ ((unused
)), const char *objname
,
2163 const char *errstring
)
2165 if (objname
[0] == '\0')
2166 objname
= RTLD_PROGNAME
;
2167 _dl_error_printf ("%s (%s)\n", errstring
, objname
);
2170 /* This is a little helper function for resolving symbols while
2171 tracing the binary. */
2173 print_missing_version (int errcode
__attribute__ ((unused
)),
2174 const char *objname
, const char *errstring
)
2176 _dl_error_printf ("%s: %s: %s\n", RTLD_PROGNAME
,
2177 objname
, errstring
);
2180 /* Nonzero if any of the debugging options is enabled. */
2181 static int any_debug attribute_relro
;
2183 /* Process the string given as the parameter which explains which debugging
2184 options are enabled. */
2186 process_dl_debug (const char *dl_debug
)
2188 /* When adding new entries make sure that the maximal length of a name
2189 is correctly handled in the LD_DEBUG_HELP code below. */
2193 const char name
[10];
2194 const char helptext
[41];
2195 unsigned short int mask
;
2198 #define LEN_AND_STR(str) sizeof (str) - 1, str
2199 { LEN_AND_STR ("libs"), "display library search paths",
2200 DL_DEBUG_LIBS
| DL_DEBUG_IMPCALLS
},
2201 { LEN_AND_STR ("reloc"), "display relocation processing",
2202 DL_DEBUG_RELOC
| DL_DEBUG_IMPCALLS
},
2203 { LEN_AND_STR ("files"), "display progress for input file",
2204 DL_DEBUG_FILES
| DL_DEBUG_IMPCALLS
},
2205 { LEN_AND_STR ("symbols"), "display symbol table processing",
2206 DL_DEBUG_SYMBOLS
| DL_DEBUG_IMPCALLS
},
2207 { LEN_AND_STR ("bindings"), "display information about symbol binding",
2208 DL_DEBUG_BINDINGS
| DL_DEBUG_IMPCALLS
},
2209 { LEN_AND_STR ("versions"), "display version dependencies",
2210 DL_DEBUG_VERSIONS
| DL_DEBUG_IMPCALLS
},
2211 { LEN_AND_STR ("scopes"), "display scope information",
2213 { LEN_AND_STR ("all"), "all previous options combined",
2214 DL_DEBUG_LIBS
| DL_DEBUG_RELOC
| DL_DEBUG_FILES
| DL_DEBUG_SYMBOLS
2215 | DL_DEBUG_BINDINGS
| DL_DEBUG_VERSIONS
| DL_DEBUG_IMPCALLS
2216 | DL_DEBUG_SCOPES
},
2217 { LEN_AND_STR ("statistics"), "display relocation statistics",
2218 DL_DEBUG_STATISTICS
},
2219 { LEN_AND_STR ("unused"), "determined unused DSOs",
2221 { LEN_AND_STR ("help"), "display this help message and exit",
2224 #define ndebopts (sizeof (debopts) / sizeof (debopts[0]))
2226 /* Skip separating white spaces and commas. */
2227 while (*dl_debug
!= '\0')
2229 if (*dl_debug
!= ' ' && *dl_debug
!= ',' && *dl_debug
!= ':')
2234 while (dl_debug
[len
] != '\0' && dl_debug
[len
] != ' '
2235 && dl_debug
[len
] != ',' && dl_debug
[len
] != ':')
2238 for (cnt
= 0; cnt
< ndebopts
; ++cnt
)
2239 if (debopts
[cnt
].len
== len
2240 && memcmp (dl_debug
, debopts
[cnt
].name
, len
) == 0)
2242 GLRO(dl_debug_mask
) |= debopts
[cnt
].mask
;
2247 if (cnt
== ndebopts
)
2249 /* Display a warning and skip everything until next
2251 char *copy
= strndupa (dl_debug
, len
);
2252 _dl_error_printf ("\
2253 warning: debug option `%s' unknown; try LD_DEBUG=help\n", copy
);
2263 if (GLRO(dl_debug_mask
) & DL_DEBUG_UNUSED
)
2265 /* In order to get an accurate picture of whether a particular
2266 DT_NEEDED entry is actually used we have to process both
2267 the PLT and non-PLT relocation entries. */
2271 if (GLRO(dl_debug_mask
) & DL_DEBUG_HELP
)
2276 Valid options for the LD_DEBUG environment variable are:\n\n");
2278 for (cnt
= 0; cnt
< ndebopts
; ++cnt
)
2279 _dl_printf (" %.*s%s%s\n", debopts
[cnt
].len
, debopts
[cnt
].name
,
2280 " " + debopts
[cnt
].len
- 3,
2281 debopts
[cnt
].helptext
);
2284 To direct the debugging output into a file instead of standard output\n\
2285 a filename can be specified using the LD_DEBUG_OUTPUT environment variable.\n");
2291 process_dl_audit (char *str
)
2293 /* The parameter is a colon separated list of DSO names. */
2296 while ((p
= (strsep
) (&str
, ":")) != NULL
)
2298 && (__builtin_expect (! __libc_enable_secure
, 1)
2299 || strchr (p
, '/') == NULL
))
2301 /* This is using the local malloc, not the system malloc. The
2302 memory can never be freed. */
2303 struct audit_list
*newp
= malloc (sizeof (*newp
));
2306 if (audit_list
== NULL
)
2307 audit_list
= newp
->next
= newp
;
2310 newp
->next
= audit_list
->next
;
2311 audit_list
= audit_list
->next
= newp
;
2316 /* Process all environments variables the dynamic linker must recognize.
2317 Since all of them start with `LD_' we are a bit smarter while finding
2319 extern char **_environ attribute_hidden
;
2323 process_envvars (enum mode
*modep
)
2325 char **runp
= _environ
;
2327 enum mode mode
= normal
;
2328 char *debug_output
= NULL
;
2330 /* This is the default place for profiling data file. */
2331 GLRO(dl_profile_output
)
2332 = &"/var/tmp\0/var/profile"[__libc_enable_secure
? 9 : 0];
2334 while ((envline
= _dl_next_ld_env_entry (&runp
)) != NULL
)
2338 while (envline
[len
] != '\0' && envline
[len
] != '=')
2341 if (envline
[len
] != '=')
2342 /* This is a "LD_" variable at the end of the string without
2343 a '=' character. Ignore it since otherwise we will access
2344 invalid memory below. */
2350 /* Warning level, verbose or not. */
2351 if (memcmp (envline
, "WARN", 4) == 0)
2352 GLRO(dl_verbose
) = envline
[5] != '\0';
2356 /* Debugging of the dynamic linker? */
2357 if (memcmp (envline
, "DEBUG", 5) == 0)
2359 process_dl_debug (&envline
[6]);
2362 if (memcmp (envline
, "AUDIT", 5) == 0)
2363 process_dl_audit (&envline
[6]);
2367 /* Print information about versions. */
2368 if (memcmp (envline
, "VERBOSE", 7) == 0)
2370 version_info
= envline
[8] != '\0';
2374 /* List of objects to be preloaded. */
2375 if (memcmp (envline
, "PRELOAD", 7) == 0)
2377 preloadlist
= &envline
[8];
2381 /* Which shared object shall be profiled. */
2382 if (memcmp (envline
, "PROFILE", 7) == 0 && envline
[8] != '\0')
2383 GLRO(dl_profile
) = &envline
[8];
2387 /* Do we bind early? */
2388 if (memcmp (envline
, "BIND_NOW", 8) == 0)
2390 GLRO(dl_lazy
) = envline
[9] == '\0';
2393 if (memcmp (envline
, "BIND_NOT", 8) == 0)
2394 GLRO(dl_bind_not
) = envline
[9] != '\0';
2398 /* Test whether we want to see the content of the auxiliary
2399 array passed up from the kernel. */
2400 if (!__libc_enable_secure
2401 && memcmp (envline
, "SHOW_AUXV", 9) == 0)
2406 /* Mask for the important hardware capabilities. */
2407 if (!__libc_enable_secure
2408 && memcmp (envline
, "HWCAP_MASK", 10) == 0)
2409 GLRO(dl_hwcap_mask
) = __strtoul_internal (&envline
[11], NULL
,
2414 /* Path where the binary is found. */
2415 if (!__libc_enable_secure
2416 && memcmp (envline
, "ORIGIN_PATH", 11) == 0)
2417 GLRO(dl_origin_path
) = &envline
[12];
2421 /* The library search path. */
2422 if (memcmp (envline
, "LIBRARY_PATH", 12) == 0)
2424 library_path
= &envline
[13];
2428 /* Where to place the profiling data file. */
2429 if (memcmp (envline
, "DEBUG_OUTPUT", 12) == 0)
2431 debug_output
= &envline
[13];
2435 if (!__libc_enable_secure
2436 && memcmp (envline
, "DYNAMIC_WEAK", 12) == 0)
2437 GLRO(dl_dynamic_weak
) = 1;
2441 /* We might have some extra environment variable with length 13
2443 #ifdef EXTRA_LD_ENVVARS_13
2446 if (!__libc_enable_secure
2447 && memcmp (envline
, "USE_LOAD_BIAS", 13) == 0)
2449 GLRO(dl_use_load_bias
) = envline
[14] == '1' ? -1 : 0;
2455 /* Where to place the profiling data file. */
2456 if (!__libc_enable_secure
2457 && memcmp (envline
, "PROFILE_OUTPUT", 14) == 0
2458 && envline
[15] != '\0')
2459 GLRO(dl_profile_output
) = &envline
[15];
2463 /* The mode of the dynamic linker can be set. */
2464 if (memcmp (envline
, "TRACE_PRELINKING", 16) == 0)
2467 GLRO(dl_verbose
) = 1;
2468 GLRO(dl_debug_mask
) |= DL_DEBUG_PRELINK
;
2469 GLRO(dl_trace_prelink
) = &envline
[17];
2474 /* The mode of the dynamic linker can be set. */
2475 if (memcmp (envline
, "TRACE_LOADED_OBJECTS", 20) == 0)
2479 /* We might have some extra environment variable to handle. This
2480 is tricky due to the pre-processing of the length of the name
2481 in the switch statement here. The code here assumes that added
2482 environment variables have a different length. */
2483 #ifdef EXTRA_LD_ENVVARS
2489 /* The caller wants this information. */
2492 /* Extra security for SUID binaries. Remove all dangerous environment
2494 if (__builtin_expect (__libc_enable_secure
, 0))
2496 static const char unsecure_envvars
[] =
2497 #ifdef EXTRA_UNSECURE_ENVVARS
2498 EXTRA_UNSECURE_ENVVARS
2503 nextp
= unsecure_envvars
;
2507 /* We could use rawmemchr but this need not be fast. */
2508 nextp
= (char *) (strchr
) (nextp
, '\0') + 1;
2510 while (*nextp
!= '\0');
2512 if (__access ("/etc/suid-debug", F_OK
) != 0)
2515 unsetenv ("MALLOC_CHECK_");
2517 GLRO(dl_debug_mask
) = 0;
2523 /* If we have to run the dynamic linker in debugging mode and the
2524 LD_DEBUG_OUTPUT environment variable is given, we write the debug
2525 messages to this file. */
2526 else if (any_debug
&& debug_output
!= NULL
)
2529 const int flags
= O_WRONLY
| O_APPEND
| O_CREAT
| O_NOFOLLOW
;
2531 const int flags
= O_WRONLY
| O_APPEND
| O_CREAT
;
2533 size_t name_len
= strlen (debug_output
);
2534 char buf
[name_len
+ 12];
2537 buf
[name_len
+ 11] = '\0';
2538 startp
= _itoa (__getpid (), &buf
[name_len
+ 11], 10, 0);
2540 startp
= memcpy (startp
- name_len
, debug_output
, name_len
);
2542 GLRO(dl_debug_fd
) = __open (startp
, flags
, DEFFILEMODE
);
2543 if (GLRO(dl_debug_fd
) == -1)
2544 /* We use standard output if opening the file failed. */
2545 GLRO(dl_debug_fd
) = STDOUT_FILENO
;
2550 /* Print the various times we collected. */
2552 __attribute ((noinline
))
2553 print_statistics (hp_timing_t
*rtld_total_timep
)
2555 #ifndef HP_TIMING_NONAVAIL
2560 /* Total time rtld used. */
2561 if (HP_SMALL_TIMING_AVAIL
)
2563 HP_TIMING_PRINT (buf
, sizeof (buf
), *rtld_total_timep
);
2564 _dl_debug_printf ("\nruntime linker statistics:\n"
2565 " total startup time in dynamic loader: %s\n", buf
);
2567 /* Print relocation statistics. */
2569 HP_TIMING_PRINT (buf
, sizeof (buf
), relocate_time
);
2570 cp
= _itoa ((1000ULL * relocate_time
) / *rtld_total_timep
,
2571 pbuf
+ sizeof (pbuf
), 10, 0);
2573 switch (pbuf
+ sizeof (pbuf
) - cp
)
2584 _dl_debug_printf ("\
2585 time needed for relocation: %s (%s%%)\n", buf
, pbuf
);
2589 unsigned long int num_relative_relocations
= 0;
2590 for (Lmid_t ns
= 0; ns
< GL(dl_nns
); ++ns
)
2592 if (GL(dl_ns
)[ns
]._ns_loaded
== NULL
)
2595 struct r_scope_elem
*scope
= &GL(dl_ns
)[ns
]._ns_loaded
->l_searchlist
;
2597 for (unsigned int i
= 0; i
< scope
->r_nlist
; i
++)
2599 struct link_map
*l
= scope
->r_list
[i
];
2601 if (l
->l_addr
!= 0 && l
->l_info
[VERSYMIDX (DT_RELCOUNT
)])
2602 num_relative_relocations
2603 += l
->l_info
[VERSYMIDX (DT_RELCOUNT
)]->d_un
.d_val
;
2604 #ifndef ELF_MACHINE_REL_RELATIVE
2605 /* Relative relocations are processed on these architectures if
2606 library is loaded to different address than p_vaddr or
2607 if not prelinked. */
2608 if ((l
->l_addr
!= 0 || !l
->l_info
[VALIDX(DT_GNU_PRELINKED
)])
2609 && l
->l_info
[VERSYMIDX (DT_RELACOUNT
)])
2611 /* On e.g. IA-64 or Alpha, relative relocations are processed
2612 only if library is loaded to different address than p_vaddr. */
2613 if (l
->l_addr
!= 0 && l
->l_info
[VERSYMIDX (DT_RELACOUNT
)])
2615 num_relative_relocations
2616 += l
->l_info
[VERSYMIDX (DT_RELACOUNT
)]->d_un
.d_val
;
2620 _dl_debug_printf (" number of relocations: %lu\n"
2621 " number of relocations from cache: %lu\n"
2622 " number of relative relocations: %lu\n",
2623 GL(dl_num_relocations
),
2624 GL(dl_num_cache_relocations
),
2625 num_relative_relocations
);
2627 #ifndef HP_TIMING_NONAVAIL
2628 /* Time spend while loading the object and the dependencies. */
2629 if (HP_SMALL_TIMING_AVAIL
)
2632 HP_TIMING_PRINT (buf
, sizeof (buf
), load_time
);
2633 cp
= _itoa ((1000ULL * load_time
) / *rtld_total_timep
,
2634 pbuf
+ sizeof (pbuf
), 10, 0);
2636 switch (pbuf
+ sizeof (pbuf
) - cp
)
2647 _dl_debug_printf ("\
2648 time needed to load objects: %s (%s%%)\n",