1 /* Run time dynamic linker.
2 Copyright (C) 1995-2014 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
27 #include <sys/param.h>
32 #include <fpu_control.h>
33 #include <hp-timing.h>
34 #include <bits/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_pointer_guard
= 1,
166 ._dl_pagesize
= EXEC_PAGESIZE
,
167 ._dl_inhibit_cache
= 0,
169 /* Function pointers. */
170 ._dl_debug_printf
= _dl_debug_printf
,
171 ._dl_catch_error
= _dl_catch_error
,
172 ._dl_signal_error
= _dl_signal_error
,
173 ._dl_mcount
= _dl_mcount
,
174 ._dl_lookup_symbol_x
= _dl_lookup_symbol_x
,
175 ._dl_check_caller
= _dl_check_caller
,
176 ._dl_open
= _dl_open
,
177 ._dl_close
= _dl_close
,
178 ._dl_tls_get_addr_soft
= _dl_tls_get_addr_soft
,
179 #ifdef HAVE_DL_DISCOVER_OSVERSION
180 ._dl_discover_osversion
= _dl_discover_osversion
183 /* If we would use strong_alias here the compiler would see a
184 non-hidden definition. This would undo the effect of the previous
185 declaration. So spell out was strong_alias does plus add the
186 visibility attribute. */
187 extern struct rtld_global_ro _rtld_local_ro
188 __attribute__ ((alias ("_rtld_global_ro"), visibility ("hidden")));
191 static void dl_main (const ElfW(Phdr
) *phdr
, ElfW(Word
) phnum
,
192 ElfW(Addr
) *user_entry
, ElfW(auxv_t
) *auxv
);
194 /* These two variables cannot be moved into .data.rel.ro. */
195 static struct libname_list _dl_rtld_libname
;
196 static struct libname_list _dl_rtld_libname2
;
198 /* Variable for statistics. */
199 #ifndef HP_TIMING_NONAVAIL
200 static hp_timing_t relocate_time
;
201 static hp_timing_t load_time attribute_relro
;
202 static hp_timing_t start_time attribute_relro
;
205 /* Additional definitions needed by TLS initialization. */
206 #ifdef TLS_INIT_HELPER
210 /* Helper function for syscall implementation. */
211 #ifdef DL_SYSINFO_IMPLEMENTATION
212 DL_SYSINFO_IMPLEMENTATION
215 /* Before ld.so is relocated we must not access variables which need
216 relocations. This means variables which are exported. Variables
217 declared as static are fine. If we can mark a variable hidden this
218 is fine, too. The latter is important here. We can avoid setting
219 up a temporary link map for ld.so if we can mark _rtld_global as
221 #ifdef PI_STATIC_AND_HIDDEN
222 # define DONT_USE_BOOTSTRAP_MAP 1
225 #ifdef DONT_USE_BOOTSTRAP_MAP
226 static ElfW(Addr
) _dl_start_final (void *arg
);
228 struct dl_start_final_info
231 #if !defined HP_TIMING_NONAVAIL && HP_TIMING_INLINE
232 hp_timing_t start_time
;
235 static ElfW(Addr
) _dl_start_final (void *arg
,
236 struct dl_start_final_info
*info
);
239 /* These defined magically in the linker script. */
240 extern char _begin
[] attribute_hidden
;
241 extern char _etext
[] attribute_hidden
;
242 extern char _end
[] attribute_hidden
;
248 # error "sysdeps/MACHINE/dl-machine.h fails to define RTLD_START"
251 /* This is the second half of _dl_start (below). It can be inlined safely
252 under DONT_USE_BOOTSTRAP_MAP, where it is careful not to make any GOT
253 references. When the tools don't permit us to avoid using a GOT entry
254 for _dl_rtld_global (no attribute_hidden support), we must make sure
255 this function is not inlined (see below). */
257 #ifdef DONT_USE_BOOTSTRAP_MAP
258 static inline ElfW(Addr
) __attribute__ ((always_inline
))
259 _dl_start_final (void *arg
)
261 static ElfW(Addr
) __attribute__ ((noinline
))
262 _dl_start_final (void *arg
, struct dl_start_final_info
*info
)
265 ElfW(Addr
) start_addr
;
267 if (HP_SMALL_TIMING_AVAIL
)
269 /* If it hasn't happen yet record the startup time. */
270 if (! HP_TIMING_INLINE
)
271 HP_TIMING_NOW (start_time
);
272 #if !defined DONT_USE_BOOTSTRAP_MAP && !defined HP_TIMING_NONAVAIL
274 start_time
= info
->start_time
;
278 /* Transfer data about ourselves to the permanent link_map structure. */
279 #ifndef DONT_USE_BOOTSTRAP_MAP
280 GL(dl_rtld_map
).l_addr
= info
->l
.l_addr
;
281 GL(dl_rtld_map
).l_ld
= info
->l
.l_ld
;
282 memcpy (GL(dl_rtld_map
).l_info
, info
->l
.l_info
,
283 sizeof GL(dl_rtld_map
).l_info
);
284 GL(dl_rtld_map
).l_mach
= info
->l
.l_mach
;
285 GL(dl_rtld_map
).l_relocated
= 1;
287 _dl_setup_hash (&GL(dl_rtld_map
));
288 GL(dl_rtld_map
).l_real
= &GL(dl_rtld_map
);
289 GL(dl_rtld_map
).l_map_start
= (ElfW(Addr
)) _begin
;
290 GL(dl_rtld_map
).l_map_end
= (ElfW(Addr
)) _end
;
291 GL(dl_rtld_map
).l_text_end
= (ElfW(Addr
)) _etext
;
292 /* Copy the TLS related data if necessary. */
293 #ifndef DONT_USE_BOOTSTRAP_MAP
294 # if NO_TLS_OFFSET != 0
295 GL(dl_rtld_map
).l_tls_offset
= NO_TLS_OFFSET
;
299 HP_TIMING_NOW (GL(dl_cpuclock_offset
));
301 /* Initialize the stack end variable. */
302 __libc_stack_end
= __builtin_frame_address (0);
304 /* Call the OS-dependent function to set up life so we can do things like
305 file access. It will call `dl_main' (below) to do all the real work
306 of the dynamic linker, and then unwind our frame and run the user
307 entry point on the same stack we entered on. */
308 start_addr
= _dl_sysdep_start (arg
, &dl_main
);
310 #ifndef HP_TIMING_NONAVAIL
311 hp_timing_t rtld_total_time
;
312 if (HP_SMALL_TIMING_AVAIL
)
314 hp_timing_t end_time
;
316 /* Get the current time. */
317 HP_TIMING_NOW (end_time
);
319 /* Compute the difference. */
320 HP_TIMING_DIFF (rtld_total_time
, start_time
, end_time
);
324 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_STATISTICS
))
326 #ifndef HP_TIMING_NONAVAIL
327 print_statistics (&rtld_total_time
);
329 print_statistics (NULL
);
336 static ElfW(Addr
) __attribute_used__ internal_function
337 _dl_start (void *arg
)
339 #ifdef DONT_USE_BOOTSTRAP_MAP
340 # define bootstrap_map GL(dl_rtld_map)
342 struct dl_start_final_info info
;
343 # define bootstrap_map info.l
346 /* This #define produces dynamic linking inline functions for
347 bootstrap relocation instead of general-purpose relocation.
348 Since ld.so must not have any undefined symbols the result
349 is trivial: always the map of ld.so itself. */
350 #define RTLD_BOOTSTRAP
351 #define RESOLVE_MAP(sym, version, flags) (&bootstrap_map)
352 #include "dynamic-link.h"
354 if (HP_TIMING_INLINE
&& HP_SMALL_TIMING_AVAIL
)
355 #ifdef DONT_USE_BOOTSTRAP_MAP
356 HP_TIMING_NOW (start_time
);
358 HP_TIMING_NOW (info
.start_time
);
361 /* Partly clean the `bootstrap_map' structure up. Don't use
362 `memset' since it might not be built in or inlined and we cannot
363 make function calls at this point. Use '__builtin_memset' if we
364 know it is available. We do not have to clear the memory if we
365 do not have to use the temporary bootstrap_map. Global variables
366 are initialized to zero by default. */
367 #ifndef DONT_USE_BOOTSTRAP_MAP
368 # ifdef HAVE_BUILTIN_MEMSET
369 __builtin_memset (bootstrap_map
.l_info
, '\0', sizeof (bootstrap_map
.l_info
));
372 cnt
< sizeof (bootstrap_map
.l_info
) / sizeof (bootstrap_map
.l_info
[0]);
374 bootstrap_map
.l_info
[cnt
] = 0;
378 /* Figure out the run-time load address of the dynamic linker itself. */
379 bootstrap_map
.l_addr
= elf_machine_load_address ();
381 /* Read our own dynamic section and fill in the info array. */
382 bootstrap_map
.l_ld
= (void *) bootstrap_map
.l_addr
+ elf_machine_dynamic ();
383 elf_get_dynamic_info (&bootstrap_map
, NULL
);
385 #if NO_TLS_OFFSET != 0
386 bootstrap_map
.l_tls_offset
= NO_TLS_OFFSET
;
389 #ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
390 ELF_MACHINE_BEFORE_RTLD_RELOC (bootstrap_map
.l_info
);
393 if (bootstrap_map
.l_addr
|| ! bootstrap_map
.l_info
[VALIDX(DT_GNU_PRELINKED
)])
395 /* Relocate ourselves so we can do normal function calls and
396 data access using the global offset table. */
398 ELF_DYNAMIC_RELOCATE (&bootstrap_map
, 0, 0, 0);
400 bootstrap_map
.l_relocated
= 1;
402 /* Please note that we don't allow profiling of this object and
403 therefore need not test whether we have to allocate the array
404 for the relocation results (as done in dl-reloc.c). */
406 /* Now life is sane; we can call functions and access global data.
407 Set up to use the operating system facilities, and find out from
408 the operating system's program loader where to find the program
409 header table in core. Put the rest of _dl_start into a separate
410 function, that way the compiler cannot put accesses to the GOT
411 before ELF_DYNAMIC_RELOCATE. */
413 #ifdef DONT_USE_BOOTSTRAP_MAP
414 ElfW(Addr
) entry
= _dl_start_final (arg
);
416 ElfW(Addr
) entry
= _dl_start_final (arg
, &info
);
419 #ifndef ELF_MACHINE_START_ADDRESS
420 # define ELF_MACHINE_START_ADDRESS(map, start) (start)
423 return ELF_MACHINE_START_ADDRESS (GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
, entry
);
429 /* Now life is peachy; we can do all normal operations.
430 On to the real work. */
432 /* Some helper functions. */
434 /* Arguments to relocate_doit. */
443 /* Argument to map_doit. */
445 struct link_map
*loader
;
447 /* Return value of map_doit. */
448 struct link_map
*map
;
454 struct link_map
*map
;
460 struct link_map
*map
;
464 /* Arguments to version_check_doit. */
465 struct version_check_args
472 relocate_doit (void *a
)
474 struct relocate_args
*args
= (struct relocate_args
*) a
;
476 _dl_relocate_object (args
->l
, args
->l
->l_scope
, args
->reloc_mode
, 0);
482 struct map_args
*args
= (struct map_args
*) a
;
483 int type
= (args
->mode
== __RTLD_OPENEXEC
) ? lt_executable
: lt_library
;
484 args
->map
= _dl_map_object (args
->loader
, args
->str
, type
, 0,
485 args
->mode
, LM_ID_BASE
);
489 dlmopen_doit (void *a
)
491 struct dlmopen_args
*args
= (struct dlmopen_args
*) a
;
492 args
->map
= _dl_open (args
->fname
,
493 (RTLD_LAZY
| __RTLD_DLOPEN
| __RTLD_AUDIT
495 dl_main
, LM_ID_NEWLM
, _dl_argc
, _dl_argv
,
500 lookup_doit (void *a
)
502 struct lookup_args
*args
= (struct lookup_args
*) a
;
503 const ElfW(Sym
) *ref
= NULL
;
505 lookup_t l
= _dl_lookup_symbol_x (args
->name
, args
->map
, &ref
,
506 args
->map
->l_local_scope
, NULL
, 0,
507 DL_LOOKUP_RETURN_NEWEST
, NULL
);
509 args
->result
= DL_SYMBOL_ADDRESS (l
, ref
);
513 version_check_doit (void *a
)
515 struct version_check_args
*args
= (struct version_check_args
*) a
;
516 if (_dl_check_all_versions (GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
, 1,
517 args
->dotrace
) && args
->doexit
)
518 /* We cannot start the application. Abort now. */
523 static inline struct link_map
*
524 find_needed (const char *name
)
526 struct r_scope_elem
*scope
= &GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
->l_searchlist
;
527 unsigned int n
= scope
->r_nlist
;
530 if (_dl_name_match_p (name
, scope
->r_list
[n
]))
531 return scope
->r_list
[n
];
533 /* Should never happen. */
538 match_version (const char *string
, struct link_map
*map
)
540 const char *strtab
= (const void *) D_PTR (map
, l_info
[DT_STRTAB
]);
543 #define VERDEFTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERDEF))
544 if (map
->l_info
[VERDEFTAG
] == NULL
)
545 /* The file has no symbol versioning. */
548 def
= (ElfW(Verdef
) *) ((char *) map
->l_addr
549 + map
->l_info
[VERDEFTAG
]->d_un
.d_ptr
);
552 ElfW(Verdaux
) *aux
= (ElfW(Verdaux
) *) ((char *) def
+ def
->vd_aux
);
554 /* Compare the version strings. */
555 if (strcmp (string
, strtab
+ aux
->vda_name
) == 0)
559 /* If no more definitions we failed to find what we want. */
560 if (def
->vd_next
== 0)
563 /* Next definition. */
564 def
= (ElfW(Verdef
) *) ((char *) def
+ def
->vd_next
);
570 static bool tls_init_tp_called
;
575 /* Number of elements in the static TLS block. */
576 GL(dl_tls_static_nelem
) = GL(dl_tls_max_dtv_idx
);
578 /* Do not do this twice. The audit interface might have required
579 the DTV interfaces to be set up early. */
580 if (GL(dl_initial_dtv
) != NULL
)
583 /* Allocate the array which contains the information about the
584 dtv slots. We allocate a few entries more than needed to
585 avoid the need for reallocation. */
586 size_t nelem
= GL(dl_tls_max_dtv_idx
) + 1 + TLS_SLOTINFO_SURPLUS
;
589 GL(dl_tls_dtv_slotinfo_list
) = (struct dtv_slotinfo_list
*)
590 calloc (sizeof (struct dtv_slotinfo_list
)
591 + nelem
* sizeof (struct dtv_slotinfo
), 1);
592 /* No need to check the return value. If memory allocation failed
593 the program would have been terminated. */
595 struct dtv_slotinfo
*slotinfo
= GL(dl_tls_dtv_slotinfo_list
)->slotinfo
;
596 GL(dl_tls_dtv_slotinfo_list
)->len
= nelem
;
597 GL(dl_tls_dtv_slotinfo_list
)->next
= NULL
;
599 /* Fill in the information from the loaded modules. No namespace
600 but the base one can be filled at this time. */
601 assert (GL(dl_ns
)[LM_ID_BASE
+ 1]._ns_loaded
== NULL
);
603 for (struct link_map
*l
= GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
; l
!= NULL
;
605 if (l
->l_tls_blocksize
!= 0)
607 /* This is a module with TLS data. Store the map reference.
608 The generation counter is zero. */
610 /* slotinfo[i].gen = 0; */
613 assert (i
== GL(dl_tls_max_dtv_idx
));
615 /* Compute the TLS offsets for the various blocks. */
616 _dl_determine_tlsoffset ();
618 /* Construct the static TLS block and the dtv for the initial
619 thread. For some platforms this will include allocating memory
620 for the thread descriptor. The memory for the TLS block will
621 never be freed. It should be allocated accordingly. The dtv
622 array can be changed if dynamic loading requires it. */
623 void *tcbp
= _dl_allocate_tls_storage ();
626 cannot allocate TLS data structures for initial thread");
628 /* Store for detection of the special case by __tls_get_addr
629 so it knows not to pass this dtv to the normal realloc. */
630 GL(dl_initial_dtv
) = GET_DTV (tcbp
);
632 /* And finally install it for the main thread. */
633 const char *lossage
= TLS_INIT_TP (tcbp
);
634 if (__glibc_unlikely (lossage
!= NULL
))
635 _dl_fatal_printf ("cannot set up thread-local storage: %s\n", lossage
);
636 tls_init_tp_called
= true;
641 #ifdef _LIBC_REENTRANT
642 /* _dl_error_catch_tsd points to this for the single-threaded case.
643 It's reset by the thread library for multithreaded programs. */
644 void ** __attribute__ ((const))
645 _dl_initial_error_catch_tsd (void)
654 do_preload (char *fname
, struct link_map
*main_map
, const char *where
)
657 const char *err_str
= NULL
;
658 struct map_args args
;
662 args
.loader
= main_map
;
663 args
.mode
= __RTLD_SECURE
;
665 unsigned int old_nloaded
= GL(dl_ns
)[LM_ID_BASE
]._ns_nloaded
;
667 (void) _dl_catch_error (&objname
, &err_str
, &malloced
, map_doit
, &args
);
668 if (__glibc_unlikely (err_str
!= NULL
))
671 ERROR: ld.so: object '%s' from %s cannot be preloaded (%s): ignored.\n",
672 fname
, where
, err_str
);
673 /* No need to call free, this is still before
674 the libc's malloc is used. */
676 else if (GL(dl_ns
)[LM_ID_BASE
]._ns_nloaded
!= old_nloaded
)
677 /* It is no duplicate. */
680 /* Nothing loaded. */
684 #if defined SHARED && defined _LIBC_REENTRANT \
685 && defined __rtld_lock_default_lock_recursive
687 rtld_lock_default_lock_recursive (void *lock
)
689 __rtld_lock_default_lock_recursive (lock
);
693 rtld_lock_default_unlock_recursive (void *lock
)
695 __rtld_lock_default_unlock_recursive (lock
);
703 /* Set up the stack checker's canary. */
704 uintptr_t stack_chk_guard
= _dl_setup_stack_chk_guard (_dl_random
);
705 #ifdef THREAD_SET_STACK_GUARD
706 THREAD_SET_STACK_GUARD (stack_chk_guard
);
708 __stack_chk_guard
= stack_chk_guard
;
711 /* Set up the pointer guard as well, if necessary. */
712 if (GLRO(dl_pointer_guard
))
714 uintptr_t pointer_chk_guard
= _dl_setup_pointer_guard (_dl_random
,
716 #ifdef THREAD_SET_POINTER_GUARD
717 THREAD_SET_POINTER_GUARD (pointer_chk_guard
);
719 __pointer_chk_guard_local
= pointer_chk_guard
;
722 /* We do not need the _dl_random value anymore. The less
723 information we leave behind, the better, so clear the
728 #include "setup-vdso.h"
730 /* The library search path. */
731 static const char *library_path attribute_relro
;
732 /* The list preloaded objects. */
733 static const char *preloadlist attribute_relro
;
734 /* Nonzero if information about versions has to be printed. */
735 static int version_info attribute_relro
;
738 dl_main (const ElfW(Phdr
) *phdr
,
740 ElfW(Addr
) *user_entry
,
743 const ElfW(Phdr
) *ph
;
745 struct link_map
*main_map
;
748 bool has_interp
= false;
750 bool prelinked
= false;
751 bool rtld_is_main
= false;
752 #ifndef HP_TIMING_NONAVAIL
759 #ifdef _LIBC_REENTRANT
760 /* Explicit initialization since the reloc would just be more work. */
761 GL(dl_error_catch_tsd
) = &_dl_initial_error_catch_tsd
;
764 GL(dl_init_static_tls
) = &_dl_nothread_init_static_tls
;
766 #if defined SHARED && defined _LIBC_REENTRANT \
767 && defined __rtld_lock_default_lock_recursive
768 GL(dl_rtld_lock_recursive
) = rtld_lock_default_lock_recursive
;
769 GL(dl_rtld_unlock_recursive
) = rtld_lock_default_unlock_recursive
;
772 /* The explicit initialization here is cheaper than processing the reloc
773 in the _rtld_local definition's initializer. */
774 GL(dl_make_stack_executable_hook
) = &_dl_make_stack_executable
;
776 /* Process the environment variable which control the behaviour. */
777 process_envvars (&mode
);
779 #ifndef HAVE_INLINED_SYSCALLS
780 /* Set up a flag which tells we are just starting. */
784 if (*user_entry
== (ElfW(Addr
)) ENTRY_POINT
)
786 /* Ho ho. We are not the program interpreter! We are the program
787 itself! This means someone ran ld.so as a command. Well, that
788 might be convenient to do sometimes. We support it by
789 interpreting the args like this:
791 ld.so PROGRAM ARGS...
793 The first argument is the name of a file containing an ELF
794 executable we will load and run with the following arguments.
795 To simplify life here, PROGRAM is searched for using the
796 normal rules for shared objects, rather than $PATH or anything
797 like that. We just load it and use its entry point; we don't
798 pay attention to its PT_INTERP command (we are the interpreter
799 ourselves). This is an easy way to test a new ld.so before
803 /* Note the place where the dynamic linker actually came from. */
804 GL(dl_rtld_map
).l_name
= rtld_progname
;
807 if (! strcmp (_dl_argv
[1], "--list"))
810 GLRO(dl_lazy
) = -1; /* This means do no dependency analysis. */
816 else if (! strcmp (_dl_argv
[1], "--verify"))
824 else if (! strcmp (_dl_argv
[1], "--inhibit-cache"))
826 GLRO(dl_inhibit_cache
) = 1;
831 else if (! strcmp (_dl_argv
[1], "--library-path")
834 library_path
= _dl_argv
[2];
840 else if (! strcmp (_dl_argv
[1], "--inhibit-rpath")
843 GLRO(dl_inhibit_rpath
) = _dl_argv
[2];
849 else if (! strcmp (_dl_argv
[1], "--audit") && _dl_argc
> 2)
851 process_dl_audit (_dl_argv
[2]);
860 /* If we have no further argument the program was called incorrectly.
861 Grant the user some education. */
864 Usage: ld.so [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\
865 You have invoked `ld.so', the helper program for shared library executables.\n\
866 This program usually lives in the file `/lib/ld.so', and special directives\n\
867 in executable files using ELF shared libraries tell the system's program\n\
868 loader to load the helper program from this file. This helper program loads\n\
869 the shared libraries needed by the program executable, prepares the program\n\
870 to run, and runs it. You may invoke this helper program directly from the\n\
871 command line to load and run an ELF executable file; this is like executing\n\
872 that file itself, but always uses this helper program from the file you\n\
873 specified, instead of the helper program file specified in the executable\n\
874 file you run. This is mostly of use for maintainers to test new versions\n\
875 of this helper program; chances are you did not intend to run this program.\n\
877 --list list all dependencies and how they are resolved\n\
878 --verify verify that given object really is a dynamically linked\n\
879 object we can handle\n\
880 --inhibit-cache Do not use " LD_SO_CACHE
"\n\
881 --library-path PATH use given PATH instead of content of the environment\n\
882 variable LD_LIBRARY_PATH\n\
883 --inhibit-rpath LIST ignore RUNPATH and RPATH information in object names\n\
885 --audit LIST use objects named in LIST as auditors\n");
891 /* The initialization of _dl_stack_flags done below assumes the
892 executable's PT_GNU_STACK may have been honored by the kernel, and
893 so a PT_GNU_STACK with PF_X set means the stack started out with
894 execute permission. However, this is not really true if the
895 dynamic linker is the executable the kernel loaded. For this
896 case, we must reinitialize _dl_stack_flags to match the dynamic
897 linker itself. If the dynamic linker was built with a
898 PT_GNU_STACK, then the kernel may have loaded us with a
899 nonexecutable stack that we will have to make executable when we
900 load the program below unless it has a PT_GNU_STACK indicating
901 nonexecutable stack is ok. */
903 for (ph
= phdr
; ph
< &phdr
[phnum
]; ++ph
)
904 if (ph
->p_type
== PT_GNU_STACK
)
906 GL(dl_stack_flags
) = ph
->p_flags
;
910 if (__builtin_expect (mode
, normal
) == verify
)
913 const char *err_str
= NULL
;
914 struct map_args args
;
917 args
.str
= rtld_progname
;
919 args
.mode
= __RTLD_OPENEXEC
;
920 (void) _dl_catch_error (&objname
, &err_str
, &malloced
, map_doit
,
922 if (__glibc_unlikely (err_str
!= NULL
))
923 /* We don't free the returned string, the programs stops
925 _exit (EXIT_FAILURE
);
929 HP_TIMING_NOW (start
);
930 _dl_map_object (NULL
, rtld_progname
, lt_executable
, 0,
931 __RTLD_OPENEXEC
, LM_ID_BASE
);
932 HP_TIMING_NOW (stop
);
934 HP_TIMING_DIFF (load_time
, start
, stop
);
937 /* Now the map for the main executable is available. */
938 main_map
= GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
;
940 if (__builtin_expect (mode
, normal
) == normal
941 && GL(dl_rtld_map
).l_info
[DT_SONAME
] != NULL
942 && main_map
->l_info
[DT_SONAME
] != NULL
943 && strcmp ((const char *) D_PTR (&GL(dl_rtld_map
), l_info
[DT_STRTAB
])
944 + GL(dl_rtld_map
).l_info
[DT_SONAME
]->d_un
.d_val
,
945 (const char *) D_PTR (main_map
, l_info
[DT_STRTAB
])
946 + main_map
->l_info
[DT_SONAME
]->d_un
.d_val
) == 0)
947 _dl_fatal_printf ("loader cannot load itself\n");
949 phdr
= main_map
->l_phdr
;
950 phnum
= main_map
->l_phnum
;
951 /* We overwrite here a pointer to a malloc()ed string. But since
952 the malloc() implementation used at this point is the dummy
953 implementations which has no real free() function it does not
954 makes sense to free the old string first. */
955 main_map
->l_name
= (char *) "";
956 *user_entry
= main_map
->l_entry
;
958 #ifdef HAVE_AUX_VECTOR
959 /* Adjust the on-stack auxiliary vector so that it looks like the
960 binary was executed directly. */
961 for (ElfW(auxv_t
) *av
= auxv
; av
->a_type
!= AT_NULL
; av
++)
965 av
->a_un
.a_val
= (uintptr_t) phdr
;
968 av
->a_un
.a_val
= phnum
;
971 av
->a_un
.a_val
= *user_entry
;
974 av
->a_un
.a_val
= (uintptr_t) _dl_argv
[0];
981 /* Create a link_map for the executable itself.
982 This will be what dlopen on "" returns. */
983 main_map
= _dl_new_object ((char *) "", "", lt_executable
, NULL
,
984 __RTLD_OPENEXEC
, LM_ID_BASE
);
985 assert (main_map
!= NULL
);
986 main_map
->l_phdr
= phdr
;
987 main_map
->l_phnum
= phnum
;
988 main_map
->l_entry
= *user_entry
;
990 /* Even though the link map is not yet fully initialized we can add
991 it to the map list since there are no possible users running yet. */
992 _dl_add_to_namespace_list (main_map
, LM_ID_BASE
);
993 assert (main_map
== GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
);
995 /* At this point we are in a bit of trouble. We would have to
996 fill in the values for l_dev and l_ino. But in general we
997 do not know where the file is. We also do not handle AT_EXECFD
998 even if it would be passed up.
1000 We leave the values here defined to 0. This is normally no
1001 problem as the program code itself is normally no shared
1002 object and therefore cannot be loaded dynamically. Nothing
1003 prevent the use of dynamic binaries and in these situations
1004 we might get problems. We might not be able to find out
1005 whether the object is already loaded. But since there is no
1006 easy way out and because the dynamic binary must also not
1007 have an SONAME we ignore this program for now. If it becomes
1008 a problem we can force people using SONAMEs. */
1010 /* We delay initializing the path structure until we got the dynamic
1011 information for the program. */
1014 main_map
->l_map_end
= 0;
1015 main_map
->l_text_end
= 0;
1016 /* Perhaps the executable has no PT_LOAD header entries at all. */
1017 main_map
->l_map_start
= ~0;
1018 /* And it was opened directly. */
1019 ++main_map
->l_direct_opencount
;
1021 /* Scan the program header table for the dynamic section. */
1022 for (ph
= phdr
; ph
< &phdr
[phnum
]; ++ph
)
1026 /* Find out the load address. */
1027 main_map
->l_addr
= (ElfW(Addr
)) phdr
- ph
->p_vaddr
;
1030 /* This tells us where to find the dynamic section,
1031 which tells us everything we need to do. */
1032 main_map
->l_ld
= (void *) main_map
->l_addr
+ ph
->p_vaddr
;
1035 /* This "interpreter segment" was used by the program loader to
1036 find the program interpreter, which is this program itself, the
1037 dynamic linker. We note what name finds us, so that a future
1038 dlopen call or DT_NEEDED entry, for something that wants to link
1039 against the dynamic linker as a shared library, will know that
1040 the shared object is already loaded. */
1041 _dl_rtld_libname
.name
= ((const char *) main_map
->l_addr
1043 /* _dl_rtld_libname.next = NULL; Already zero. */
1044 GL(dl_rtld_map
).l_libname
= &_dl_rtld_libname
;
1046 /* Ordinarilly, we would get additional names for the loader from
1047 our DT_SONAME. This can't happen if we were actually linked as
1048 a static executable (detect this case when we have no DYNAMIC).
1049 If so, assume the filename component of the interpreter path to
1050 be our SONAME, and add it to our name list. */
1051 if (GL(dl_rtld_map
).l_ld
== NULL
)
1053 const char *p
= NULL
;
1054 const char *cp
= _dl_rtld_libname
.name
;
1056 /* Find the filename part of the path. */
1063 _dl_rtld_libname2
.name
= p
;
1064 /* _dl_rtld_libname2.next = NULL; Already zero. */
1065 _dl_rtld_libname
.next
= &_dl_rtld_libname2
;
1073 ElfW(Addr
) mapstart
;
1074 ElfW(Addr
) allocend
;
1076 /* Remember where the main program starts in memory. */
1077 mapstart
= (main_map
->l_addr
1078 + (ph
->p_vaddr
& ~(GLRO(dl_pagesize
) - 1)));
1079 if (main_map
->l_map_start
> mapstart
)
1080 main_map
->l_map_start
= mapstart
;
1082 /* Also where it ends. */
1083 allocend
= main_map
->l_addr
+ ph
->p_vaddr
+ ph
->p_memsz
;
1084 if (main_map
->l_map_end
< allocend
)
1085 main_map
->l_map_end
= allocend
;
1086 if ((ph
->p_flags
& PF_X
) && allocend
> main_map
->l_text_end
)
1087 main_map
->l_text_end
= allocend
;
1092 if (ph
->p_memsz
> 0)
1094 /* Note that in the case the dynamic linker we duplicate work
1095 here since we read the PT_TLS entry already in
1096 _dl_start_final. But the result is repeatable so do not
1097 check for this special but unimportant case. */
1098 main_map
->l_tls_blocksize
= ph
->p_memsz
;
1099 main_map
->l_tls_align
= ph
->p_align
;
1100 if (ph
->p_align
== 0)
1101 main_map
->l_tls_firstbyte_offset
= 0;
1103 main_map
->l_tls_firstbyte_offset
= (ph
->p_vaddr
1104 & (ph
->p_align
- 1));
1105 main_map
->l_tls_initimage_size
= ph
->p_filesz
;
1106 main_map
->l_tls_initimage
= (void *) ph
->p_vaddr
;
1108 /* This image gets the ID one. */
1109 GL(dl_tls_max_dtv_idx
) = main_map
->l_tls_modid
= 1;
1114 GL(dl_stack_flags
) = ph
->p_flags
;
1118 main_map
->l_relro_addr
= ph
->p_vaddr
;
1119 main_map
->l_relro_size
= ph
->p_memsz
;
1123 /* Adjust the address of the TLS initialization image in case
1124 the executable is actually an ET_DYN object. */
1125 if (main_map
->l_tls_initimage
!= NULL
)
1126 main_map
->l_tls_initimage
1127 = (char *) main_map
->l_tls_initimage
+ main_map
->l_addr
;
1128 if (! main_map
->l_map_end
)
1129 main_map
->l_map_end
= ~0;
1130 if (! main_map
->l_text_end
)
1131 main_map
->l_text_end
= ~0;
1132 if (! GL(dl_rtld_map
).l_libname
&& GL(dl_rtld_map
).l_name
)
1134 /* We were invoked directly, so the program might not have a
1136 _dl_rtld_libname
.name
= GL(dl_rtld_map
).l_name
;
1137 /* _dl_rtld_libname.next = NULL; Already zero. */
1138 GL(dl_rtld_map
).l_libname
= &_dl_rtld_libname
;
1141 assert (GL(dl_rtld_map
).l_libname
); /* How else did we get here? */
1143 /* If the current libname is different from the SONAME, add the
1145 if (GL(dl_rtld_map
).l_info
[DT_SONAME
] != NULL
1146 && strcmp (GL(dl_rtld_map
).l_libname
->name
,
1147 (const char *) D_PTR (&GL(dl_rtld_map
), l_info
[DT_STRTAB
])
1148 + GL(dl_rtld_map
).l_info
[DT_SONAME
]->d_un
.d_val
) != 0)
1150 static struct libname_list newname
;
1151 newname
.name
= ((char *) D_PTR (&GL(dl_rtld_map
), l_info
[DT_STRTAB
])
1152 + GL(dl_rtld_map
).l_info
[DT_SONAME
]->d_un
.d_ptr
);
1153 newname
.next
= NULL
;
1154 newname
.dont_free
= 1;
1156 assert (GL(dl_rtld_map
).l_libname
->next
== NULL
);
1157 GL(dl_rtld_map
).l_libname
->next
= &newname
;
1159 /* The ld.so must be relocated since otherwise loading audit modules
1160 will fail since they reuse the very same ld.so. */
1161 assert (GL(dl_rtld_map
).l_relocated
);
1165 /* Extract the contents of the dynamic section for easy access. */
1166 elf_get_dynamic_info (main_map
, NULL
);
1167 /* Set up our cache of pointers into the hash table. */
1168 _dl_setup_hash (main_map
);
1171 if (__builtin_expect (mode
, normal
) == verify
)
1173 /* We were called just to verify that this is a dynamic
1174 executable using us as the program interpreter. Exit with an
1175 error if we were not able to load the binary or no interpreter
1176 is specified (i.e., this is no dynamically linked binary. */
1177 if (main_map
->l_ld
== NULL
)
1180 /* We allow here some platform specific code. */
1181 #ifdef DISTINGUISH_LIB_VERSIONS
1182 DISTINGUISH_LIB_VERSIONS
;
1184 _exit (has_interp
? 0 : 2);
1187 struct link_map
**first_preload
= &GL(dl_rtld_map
).l_next
;
1188 /* Set up the data structures for the system-supplied DSO early,
1189 so they can influence _dl_init_paths. */
1190 setup_vdso (main_map
, &first_preload
);
1192 #ifdef DL_SYSDEP_OSCHECK
1193 DL_SYSDEP_OSCHECK (_dl_fatal_printf
);
1196 /* Initialize the data structures for the search paths for shared
1198 _dl_init_paths (library_path
);
1200 /* Initialize _r_debug. */
1201 struct r_debug
*r
= _dl_debug_initialize (GL(dl_rtld_map
).l_addr
,
1203 r
->r_state
= RT_CONSISTENT
;
1205 /* Put the link_map for ourselves on the chain so it can be found by
1206 name. Note that at this point the global chain of link maps contains
1207 exactly one element, which is pointed to by dl_loaded. */
1208 if (! GL(dl_rtld_map
).l_name
)
1209 /* If not invoked directly, the dynamic linker shared object file was
1210 found by the PT_INTERP name. */
1211 GL(dl_rtld_map
).l_name
= (char *) GL(dl_rtld_map
).l_libname
->name
;
1212 GL(dl_rtld_map
).l_type
= lt_library
;
1213 main_map
->l_next
= &GL(dl_rtld_map
);
1214 GL(dl_rtld_map
).l_prev
= main_map
;
1215 ++GL(dl_ns
)[LM_ID_BASE
]._ns_nloaded
;
1218 /* If LD_USE_LOAD_BIAS env variable has not been seen, default
1219 to not using bias for non-prelinked PIEs and libraries
1220 and using it for executables or prelinked PIEs or libraries. */
1221 if (GLRO(dl_use_load_bias
) == (ElfW(Addr
)) -2)
1222 GLRO(dl_use_load_bias
) = main_map
->l_addr
== 0 ? -1 : 0;
1224 /* Set up the program header information for the dynamic linker
1225 itself. It is needed in the dl_iterate_phdr callbacks. */
1226 const ElfW(Ehdr
) *rtld_ehdr
;
1228 /* Starting from binutils-2.23, the linker will define the magic symbol
1229 __ehdr_start to point to our own ELF header if it is visible in a
1230 segment that also includes the phdrs. If that's not available, we use
1231 the old method that assumes the beginning of the file is part of the
1232 lowest-addressed PT_LOAD segment. */
1233 #ifdef HAVE_EHDR_START
1234 extern const ElfW(Ehdr
) __ehdr_start
__attribute__ ((visibility ("hidden")));
1235 rtld_ehdr
= &__ehdr_start
;
1237 rtld_ehdr
= (void *) GL(dl_rtld_map
).l_map_start
;
1239 assert (rtld_ehdr
->e_ehsize
== sizeof *rtld_ehdr
);
1240 assert (rtld_ehdr
->e_phentsize
== sizeof (ElfW(Phdr
)));
1242 const ElfW(Phdr
) *rtld_phdr
= (const void *) rtld_ehdr
+ rtld_ehdr
->e_phoff
;
1244 GL(dl_rtld_map
).l_phdr
= rtld_phdr
;
1245 GL(dl_rtld_map
).l_phnum
= rtld_ehdr
->e_phnum
;
1248 /* PT_GNU_RELRO is usually the last phdr. */
1249 size_t cnt
= rtld_ehdr
->e_phnum
;
1251 if (rtld_phdr
[cnt
].p_type
== PT_GNU_RELRO
)
1253 GL(dl_rtld_map
).l_relro_addr
= rtld_phdr
[cnt
].p_vaddr
;
1254 GL(dl_rtld_map
).l_relro_size
= rtld_phdr
[cnt
].p_memsz
;
1258 /* Add the dynamic linker to the TLS list if it also uses TLS. */
1259 if (GL(dl_rtld_map
).l_tls_blocksize
!= 0)
1260 /* Assign a module ID. Do this before loading any audit modules. */
1261 GL(dl_rtld_map
).l_tls_modid
= _dl_next_tls_modid ();
1263 /* If we have auditing DSOs to load, do it now. */
1264 if (__glibc_unlikely (audit_list
!= NULL
))
1266 /* Iterate over all entries in the list. The order is important. */
1267 struct audit_ifaces
*last_audit
= NULL
;
1268 struct audit_list
*al
= audit_list
->next
;
1270 /* Since we start using the auditing DSOs right away we need to
1271 initialize the data structures now. */
1274 /* Initialize security features. We need to do it this early
1275 since otherwise the constructors of the audit libraries will
1276 use different values (especially the pointer guard) and will
1282 int tls_idx
= GL(dl_tls_max_dtv_idx
);
1284 /* Now it is time to determine the layout of the static TLS
1285 block and allocate it for the initial thread. Note that we
1286 always allocate the static block, we never defer it even if
1287 no DF_STATIC_TLS bit is set. The reason is that we know
1288 glibc will use the static model. */
1289 struct dlmopen_args dlmargs
;
1290 dlmargs
.fname
= al
->name
;
1293 const char *objname
;
1294 const char *err_str
= NULL
;
1296 (void) _dl_catch_error (&objname
, &err_str
, &malloced
, dlmopen_doit
,
1298 if (__glibc_unlikely (err_str
!= NULL
))
1301 _dl_error_printf ("\
1302 ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
1305 free ((char *) err_str
);
1309 struct lookup_args largs
;
1310 largs
.name
= "la_version";
1311 largs
.map
= dlmargs
.map
;
1313 /* Check whether the interface version matches. */
1314 (void) _dl_catch_error (&objname
, &err_str
, &malloced
,
1315 lookup_doit
, &largs
);
1317 unsigned int (*laversion
) (unsigned int);
1320 && (laversion
= largs
.result
) != NULL
1321 && (lav
= laversion (LAV_CURRENT
)) > 0
1322 && lav
<= LAV_CURRENT
)
1324 /* Allocate structure for the callback function pointers.
1325 This call can never fail. */
1328 struct audit_ifaces ifaces
;
1329 #define naudit_ifaces 8
1330 void (*fptr
[naudit_ifaces
]) (void);
1331 } *newp
= malloc (sizeof (*newp
));
1333 /* Names of the auditing interfaces. All in one
1335 static const char audit_iface_names
[] =
1340 #if __ELF_NATIVE_CLASS == 32
1342 #elif __ELF_NATIVE_CLASS == 64
1345 # error "__ELF_NATIVE_CLASS must be defined"
1347 #define STRING(s) __STRING (s)
1348 "la_" STRING (ARCH_LA_PLTENTER
) "\0"
1349 "la_" STRING (ARCH_LA_PLTEXIT
) "\0"
1351 unsigned int cnt
= 0;
1352 const char *cp
= audit_iface_names
;
1356 (void) _dl_catch_error (&objname
, &err_str
, &malloced
,
1357 lookup_doit
, &largs
);
1359 /* Store the pointer. */
1360 if (err_str
== NULL
&& largs
.result
!= NULL
)
1362 newp
->fptr
[cnt
] = largs
.result
;
1364 /* The dynamic linker link map is statically
1365 allocated, initialize the data now. */
1366 GL(dl_rtld_map
).l_audit
[cnt
].cookie
1367 = (intptr_t) &GL(dl_rtld_map
);
1370 newp
->fptr
[cnt
] = NULL
;
1373 cp
= (char *) rawmemchr (cp
, '\0') + 1;
1375 while (*cp
!= '\0');
1376 assert (cnt
== naudit_ifaces
);
1378 /* Now append the new auditing interface to the list. */
1379 newp
->ifaces
.next
= NULL
;
1380 if (last_audit
== NULL
)
1381 last_audit
= GLRO(dl_audit
) = &newp
->ifaces
;
1383 last_audit
= last_audit
->next
= &newp
->ifaces
;
1386 /* Mark the DSO as being used for auditing. */
1387 dlmargs
.map
->l_auditing
= 1;
1391 /* We cannot use the DSO, it does not have the
1392 appropriate interfaces or it expects something
1395 Lmid_t ns
= dlmargs
.map
->l_ns
;
1397 _dl_close (dlmargs
.map
);
1399 /* Make sure the namespace has been cleared entirely. */
1400 assert (GL(dl_ns
)[ns
]._ns_loaded
== NULL
);
1401 assert (GL(dl_ns
)[ns
]._ns_nloaded
== 0);
1403 GL(dl_tls_max_dtv_idx
) = tls_idx
;
1410 while (al
!= audit_list
->next
);
1412 /* If we have any auditing modules, announce that we already
1413 have two objects loaded. */
1414 if (__glibc_unlikely (GLRO(dl_naudit
) > 0))
1416 struct link_map
*ls
[2] = { main_map
, &GL(dl_rtld_map
) };
1418 for (unsigned int outer
= 0; outer
< 2; ++outer
)
1420 struct audit_ifaces
*afct
= GLRO(dl_audit
);
1421 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
1423 if (afct
->objopen
!= NULL
)
1425 ls
[outer
]->l_audit
[cnt
].bindflags
1426 = afct
->objopen (ls
[outer
], LM_ID_BASE
,
1427 &ls
[outer
]->l_audit
[cnt
].cookie
);
1429 ls
[outer
]->l_audit_any_plt
1430 |= ls
[outer
]->l_audit
[cnt
].bindflags
!= 0;
1439 /* Keep track of the currently loaded modules to count how many
1440 non-audit modules which use TLS are loaded. */
1441 size_t count_modids
= _dl_count_modids ();
1443 /* Set up debugging before the debugger is notified for the first time. */
1444 #ifdef ELF_MACHINE_DEBUG_SETUP
1445 /* Some machines (e.g. MIPS) don't use DT_DEBUG in this way. */
1446 ELF_MACHINE_DEBUG_SETUP (main_map
, r
);
1447 ELF_MACHINE_DEBUG_SETUP (&GL(dl_rtld_map
), r
);
1449 if (main_map
->l_info
[DT_DEBUG
] != NULL
)
1450 /* There is a DT_DEBUG entry in the dynamic section. Fill it in
1451 with the run-time address of the r_debug structure */
1452 main_map
->l_info
[DT_DEBUG
]->d_un
.d_ptr
= (ElfW(Addr
)) r
;
1454 /* Fill in the pointer in the dynamic linker's own dynamic section, in
1455 case you run gdb on the dynamic linker directly. */
1456 if (GL(dl_rtld_map
).l_info
[DT_DEBUG
] != NULL
)
1457 GL(dl_rtld_map
).l_info
[DT_DEBUG
]->d_un
.d_ptr
= (ElfW(Addr
)) r
;
1460 /* We start adding objects. */
1461 r
->r_state
= RT_ADD
;
1463 LIBC_PROBE (init_start
, 2, LM_ID_BASE
, r
);
1465 /* Auditing checkpoint: we are ready to signal that the initial map
1466 is being constructed. */
1467 if (__glibc_unlikely (GLRO(dl_naudit
) > 0))
1469 struct audit_ifaces
*afct
= GLRO(dl_audit
);
1470 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
1472 if (afct
->activity
!= NULL
)
1473 afct
->activity (&main_map
->l_audit
[cnt
].cookie
, LA_ACT_ADD
);
1479 /* We have two ways to specify objects to preload: via environment
1480 variable and via the file /etc/ld.so.preload. The latter can also
1481 be used when security is enabled. */
1482 assert (*first_preload
== NULL
);
1483 struct link_map
**preloads
= NULL
;
1484 unsigned int npreloads
= 0;
1486 if (__glibc_unlikely (preloadlist
!= NULL
))
1488 /* The LD_PRELOAD environment variable gives list of libraries
1489 separated by white space or colons that are loaded before the
1490 executable's dependencies and prepended to the global scope
1491 list. If the binary is running setuid all elements
1492 containing a '/' are ignored since it is insecure. */
1493 char *list
= strdupa (preloadlist
);
1496 HP_TIMING_NOW (start
);
1498 /* Prevent optimizing strsep. Speed is not important here. */
1499 while ((p
= (strsep
) (&list
, " :")) != NULL
)
1501 && (__builtin_expect (! __libc_enable_secure
, 1)
1502 || strchr (p
, '/') == NULL
))
1503 npreloads
+= do_preload (p
, main_map
, "LD_PRELOAD");
1505 HP_TIMING_NOW (stop
);
1506 HP_TIMING_DIFF (diff
, start
, stop
);
1507 HP_TIMING_ACCUM_NT (load_time
, diff
);
1510 /* There usually is no ld.so.preload file, it should only be used
1511 for emergencies and testing. So the open call etc should usually
1512 fail. Using access() on a non-existing file is faster than using
1513 open(). So we do this first. If it succeeds we do almost twice
1514 the work but this does not matter, since it is not for production
1516 static const char preload_file
[] = "/etc/ld.so.preload";
1517 if (__glibc_unlikely (__access (preload_file
, R_OK
) == 0))
1519 /* Read the contents of the file. */
1520 file
= _dl_sysdep_read_whole_file (preload_file
, &file_size
,
1521 PROT_READ
| PROT_WRITE
);
1522 if (__glibc_unlikely (file
!= MAP_FAILED
))
1524 /* Parse the file. It contains names of libraries to be loaded,
1525 separated by white spaces or `:'. It may also contain
1526 comments introduced by `#'. */
1531 /* Eliminate comments. */
1536 char *comment
= memchr (runp
, '#', rest
);
1537 if (comment
== NULL
)
1540 rest
-= comment
- runp
;
1543 while (--rest
> 0 && *++comment
!= '\n');
1546 /* We have one problematic case: if we have a name at the end of
1547 the file without a trailing terminating characters, we cannot
1548 place the \0. Handle the case separately. */
1549 if (file
[file_size
- 1] != ' ' && file
[file_size
- 1] != '\t'
1550 && file
[file_size
- 1] != '\n' && file
[file_size
- 1] != ':')
1552 problem
= &file
[file_size
];
1553 while (problem
> file
&& problem
[-1] != ' '
1554 && problem
[-1] != '\t'
1555 && problem
[-1] != '\n' && problem
[-1] != ':')
1564 file
[file_size
- 1] = '\0';
1567 HP_TIMING_NOW (start
);
1569 if (file
!= problem
)
1573 while ((p
= strsep (&runp
, ": \t\n")) != NULL
)
1575 npreloads
+= do_preload (p
, main_map
, preload_file
);
1578 if (problem
!= NULL
)
1580 char *p
= strndupa (problem
, file_size
- (problem
- file
));
1582 npreloads
+= do_preload (p
, main_map
, preload_file
);
1585 HP_TIMING_NOW (stop
);
1586 HP_TIMING_DIFF (diff
, start
, stop
);
1587 HP_TIMING_ACCUM_NT (load_time
, diff
);
1589 /* We don't need the file anymore. */
1590 __munmap (file
, file_size
);
1594 if (__glibc_unlikely (*first_preload
!= NULL
))
1596 /* Set up PRELOADS with a vector of the preloaded libraries. */
1597 struct link_map
*l
= *first_preload
;
1598 preloads
= __alloca (npreloads
* sizeof preloads
[0]);
1605 assert (i
== npreloads
);
1608 /* Load all the libraries specified by DT_NEEDED entries. If LD_PRELOAD
1609 specified some libraries to load, these are inserted before the actual
1610 dependencies in the executable's searchlist for symbol resolution. */
1611 HP_TIMING_NOW (start
);
1612 _dl_map_object_deps (main_map
, preloads
, npreloads
, mode
== trace
, 0);
1613 HP_TIMING_NOW (stop
);
1614 HP_TIMING_DIFF (diff
, start
, stop
);
1615 HP_TIMING_ACCUM_NT (load_time
, diff
);
1617 /* Mark all objects as being in the global scope. */
1618 for (i
= main_map
->l_searchlist
.r_nlist
; i
> 0; )
1619 main_map
->l_searchlist
.r_list
[--i
]->l_global
= 1;
1621 /* Remove _dl_rtld_map from the chain. */
1622 GL(dl_rtld_map
).l_prev
->l_next
= GL(dl_rtld_map
).l_next
;
1623 if (GL(dl_rtld_map
).l_next
!= NULL
)
1624 GL(dl_rtld_map
).l_next
->l_prev
= GL(dl_rtld_map
).l_prev
;
1626 for (i
= 1; i
< main_map
->l_searchlist
.r_nlist
; ++i
)
1627 if (main_map
->l_searchlist
.r_list
[i
] == &GL(dl_rtld_map
))
1630 bool rtld_multiple_ref
= false;
1631 if (__glibc_likely (i
< main_map
->l_searchlist
.r_nlist
))
1633 /* Some DT_NEEDED entry referred to the interpreter object itself, so
1634 put it back in the list of visible objects. We insert it into the
1635 chain in symbol search order because gdb uses the chain's order as
1636 its symbol search order. */
1637 rtld_multiple_ref
= true;
1639 GL(dl_rtld_map
).l_prev
= main_map
->l_searchlist
.r_list
[i
- 1];
1640 if (__builtin_expect (mode
, normal
) == normal
)
1642 GL(dl_rtld_map
).l_next
= (i
+ 1 < main_map
->l_searchlist
.r_nlist
1643 ? main_map
->l_searchlist
.r_list
[i
+ 1]
1645 #ifdef NEED_DL_SYSINFO_DSO
1646 if (GLRO(dl_sysinfo_map
) != NULL
1647 && GL(dl_rtld_map
).l_prev
->l_next
== GLRO(dl_sysinfo_map
)
1648 && GL(dl_rtld_map
).l_next
!= GLRO(dl_sysinfo_map
))
1649 GL(dl_rtld_map
).l_prev
= GLRO(dl_sysinfo_map
);
1653 /* In trace mode there might be an invisible object (which we
1654 could not find) after the previous one in the search list.
1655 In this case it doesn't matter much where we put the
1656 interpreter object, so we just initialize the list pointer so
1657 that the assertion below holds. */
1658 GL(dl_rtld_map
).l_next
= GL(dl_rtld_map
).l_prev
->l_next
;
1660 assert (GL(dl_rtld_map
).l_prev
->l_next
== GL(dl_rtld_map
).l_next
);
1661 GL(dl_rtld_map
).l_prev
->l_next
= &GL(dl_rtld_map
);
1662 if (GL(dl_rtld_map
).l_next
!= NULL
)
1664 assert (GL(dl_rtld_map
).l_next
->l_prev
== GL(dl_rtld_map
).l_prev
);
1665 GL(dl_rtld_map
).l_next
->l_prev
= &GL(dl_rtld_map
);
1669 /* Now let us see whether all libraries are available in the
1670 versions we need. */
1672 struct version_check_args args
;
1673 args
.doexit
= mode
== normal
;
1674 args
.dotrace
= mode
== trace
;
1675 _dl_receive_error (print_missing_version
, version_check_doit
, &args
);
1678 /* We do not initialize any of the TLS functionality unless any of the
1679 initial modules uses TLS. This makes dynamic loading of modules with
1680 TLS impossible, but to support it requires either eagerly doing setup
1681 now or lazily doing it later. Doing it now makes us incompatible with
1682 an old kernel that can't perform TLS_INIT_TP, even if no TLS is ever
1683 used. Trying to do it lazily is too hairy to try when there could be
1684 multiple threads (from a non-TLS-using libpthread). */
1685 bool was_tls_init_tp_called
= tls_init_tp_called
;
1689 if (__glibc_likely (audit_list
== NULL
))
1690 /* Initialize security features. But only if we have not done it
1694 if (__builtin_expect (mode
, normal
) != normal
)
1696 /* We were run just to list the shared libraries. It is
1697 important that we do this before real relocation, because the
1698 functions we call below for output may no longer work properly
1699 after relocation. */
1702 if (GLRO(dl_debug_mask
) & DL_DEBUG_PRELINK
)
1704 struct r_scope_elem
*scope
= &main_map
->l_searchlist
;
1706 for (i
= 0; i
< scope
->r_nlist
; i
++)
1708 l
= scope
->r_list
[i
];
1711 _dl_printf ("\t%s => not found\n", l
->l_libname
->name
);
1714 if (_dl_name_match_p (GLRO(dl_trace_prelink
), l
))
1715 GLRO(dl_trace_prelink_map
) = l
;
1716 _dl_printf ("\t%s => %s (0x%0*Zx, 0x%0*Zx)",
1717 DSO_FILENAME (l
->l_libname
->name
),
1718 DSO_FILENAME (l
->l_name
),
1719 (int) sizeof l
->l_map_start
* 2,
1720 (size_t) l
->l_map_start
,
1721 (int) sizeof l
->l_addr
* 2,
1722 (size_t) l
->l_addr
);
1725 _dl_printf (" TLS(0x%Zx, 0x%0*Zx)\n", l
->l_tls_modid
,
1726 (int) sizeof l
->l_tls_offset
* 2,
1727 (size_t) l
->l_tls_offset
);
1732 else if (GLRO(dl_debug_mask
) & DL_DEBUG_UNUSED
)
1734 /* Look through the dependencies of the main executable
1735 and determine which of them is not actually
1737 struct link_map
*l
= main_map
;
1739 /* Relocate the main executable. */
1740 struct relocate_args args
= { .l
= l
,
1741 .reloc_mode
= ((GLRO(dl_lazy
)
1743 | __RTLD_NOIFUNC
) };
1744 _dl_receive_error (print_unresolved
, relocate_doit
, &args
);
1746 /* This loop depends on the dependencies of the executable to
1747 correspond in number and order to the DT_NEEDED entries. */
1748 ElfW(Dyn
) *dyn
= main_map
->l_ld
;
1750 while (dyn
->d_tag
!= DT_NULL
)
1752 if (dyn
->d_tag
== DT_NEEDED
)
1755 #ifdef NEED_DL_SYSINFO_DSO
1756 /* Skip the VDSO since it's not part of the list
1757 of objects we brought in via DT_NEEDED entries. */
1758 if (l
== GLRO(dl_sysinfo_map
))
1765 _dl_printf ("Unused direct dependencies:\n");
1769 _dl_printf ("\t%s\n", l
->l_name
);
1776 _exit (first
!= true);
1778 else if (! main_map
->l_info
[DT_NEEDED
])
1779 _dl_printf ("\tstatically linked\n");
1782 for (l
= main_map
->l_next
; l
; l
= l
->l_next
)
1784 /* The library was not found. */
1785 _dl_printf ("\t%s => not found\n", l
->l_libname
->name
);
1786 else if (strcmp (l
->l_libname
->name
, l
->l_name
) == 0)
1787 _dl_printf ("\t%s (0x%0*Zx)\n", l
->l_libname
->name
,
1788 (int) sizeof l
->l_map_start
* 2,
1789 (size_t) l
->l_map_start
);
1791 _dl_printf ("\t%s => %s (0x%0*Zx)\n", l
->l_libname
->name
,
1792 l
->l_name
, (int) sizeof l
->l_map_start
* 2,
1793 (size_t) l
->l_map_start
);
1796 if (__builtin_expect (mode
, trace
) != trace
)
1797 for (i
= 1; i
< (unsigned int) _dl_argc
; ++i
)
1799 const ElfW(Sym
) *ref
= NULL
;
1800 ElfW(Addr
) loadbase
;
1803 result
= _dl_lookup_symbol_x (_dl_argv
[i
], main_map
,
1804 &ref
, main_map
->l_scope
,
1805 NULL
, ELF_RTYPE_CLASS_PLT
,
1806 DL_LOOKUP_ADD_DEPENDENCY
, NULL
);
1808 loadbase
= LOOKUP_VALUE_ADDRESS (result
);
1810 _dl_printf ("%s found at 0x%0*Zd in object at 0x%0*Zd\n",
1812 (int) sizeof ref
->st_value
* 2,
1813 (size_t) ref
->st_value
,
1814 (int) sizeof loadbase
* 2, (size_t) loadbase
);
1818 /* If LD_WARN is set, warn about undefined symbols. */
1819 if (GLRO(dl_lazy
) >= 0 && GLRO(dl_verbose
))
1821 /* We have to do symbol dependency testing. */
1822 struct relocate_args args
;
1825 args
.reloc_mode
= ((GLRO(dl_lazy
) ? RTLD_LAZY
: 0)
1828 i
= main_map
->l_searchlist
.r_nlist
;
1831 struct link_map
*l
= main_map
->l_initfini
[i
];
1832 if (l
!= &GL(dl_rtld_map
) && ! l
->l_faked
)
1835 _dl_receive_error (print_unresolved
, relocate_doit
,
1840 if ((GLRO(dl_debug_mask
) & DL_DEBUG_PRELINK
)
1841 && rtld_multiple_ref
)
1843 /* Mark the link map as not yet relocated again. */
1844 GL(dl_rtld_map
).l_relocated
= 0;
1845 _dl_relocate_object (&GL(dl_rtld_map
),
1846 main_map
->l_scope
, __RTLD_NOIFUNC
, 0);
1849 #define VERNEEDTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERNEED))
1852 /* Print more information. This means here, print information
1853 about the versions needed. */
1855 struct link_map
*map
;
1857 for (map
= main_map
; map
!= NULL
; map
= map
->l_next
)
1860 ElfW(Dyn
) *dyn
= map
->l_info
[VERNEEDTAG
];
1866 strtab
= (const void *) D_PTR (map
, l_info
[DT_STRTAB
]);
1867 ent
= (ElfW(Verneed
) *) (map
->l_addr
+ dyn
->d_un
.d_ptr
);
1871 _dl_printf ("\n\tVersion information:\n");
1875 _dl_printf ("\t%s:\n", DSO_FILENAME (map
->l_name
));
1880 struct link_map
*needed
;
1882 needed
= find_needed (strtab
+ ent
->vn_file
);
1883 aux
= (ElfW(Vernaux
) *) ((char *) ent
+ ent
->vn_aux
);
1887 const char *fname
= NULL
;
1890 && match_version (strtab
+ aux
->vna_name
,
1892 fname
= needed
->l_name
;
1894 _dl_printf ("\t\t%s (%s) %s=> %s\n",
1895 strtab
+ ent
->vn_file
,
1896 strtab
+ aux
->vna_name
,
1897 aux
->vna_flags
& VER_FLG_WEAK
1899 fname
?: "not found");
1901 if (aux
->vna_next
== 0)
1902 /* No more symbols. */
1906 aux
= (ElfW(Vernaux
) *) ((char *) aux
1910 if (ent
->vn_next
== 0)
1911 /* No more dependencies. */
1914 /* Next dependency. */
1915 ent
= (ElfW(Verneed
) *) ((char *) ent
+ ent
->vn_next
);
1924 if (main_map
->l_info
[ADDRIDX (DT_GNU_LIBLIST
)]
1925 && ! __builtin_expect (GLRO(dl_profile
) != NULL
, 0)
1926 && ! __builtin_expect (GLRO(dl_dynamic_weak
), 0))
1928 ElfW(Lib
) *liblist
, *liblistend
;
1929 struct link_map
**r_list
, **r_listend
, *l
;
1930 const char *strtab
= (const void *) D_PTR (main_map
, l_info
[DT_STRTAB
]);
1932 assert (main_map
->l_info
[VALIDX (DT_GNU_LIBLISTSZ
)] != NULL
);
1933 liblist
= (ElfW(Lib
) *)
1934 main_map
->l_info
[ADDRIDX (DT_GNU_LIBLIST
)]->d_un
.d_ptr
;
1935 liblistend
= (ElfW(Lib
) *)
1937 main_map
->l_info
[VALIDX (DT_GNU_LIBLISTSZ
)]->d_un
.d_val
);
1938 r_list
= main_map
->l_searchlist
.r_list
;
1939 r_listend
= r_list
+ main_map
->l_searchlist
.r_nlist
;
1941 for (; r_list
< r_listend
&& liblist
< liblistend
; r_list
++)
1948 /* If the library is not mapped where it should, fail. */
1952 /* Next, check if checksum matches. */
1953 if (l
->l_info
[VALIDX(DT_CHECKSUM
)] == NULL
1954 || l
->l_info
[VALIDX(DT_CHECKSUM
)]->d_un
.d_val
1955 != liblist
->l_checksum
)
1958 if (l
->l_info
[VALIDX(DT_GNU_PRELINKED
)] == NULL
1959 || l
->l_info
[VALIDX(DT_GNU_PRELINKED
)]->d_un
.d_val
1960 != liblist
->l_time_stamp
)
1963 if (! _dl_name_match_p (strtab
+ liblist
->l_name
, l
))
1970 if (r_list
== r_listend
&& liblist
== liblistend
)
1973 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_LIBS
))
1974 _dl_debug_printf ("\nprelink checking: %s\n",
1975 prelinked
? "ok" : "failed");
1979 /* Now set up the variable which helps the assembler startup code. */
1980 GL(dl_ns
)[LM_ID_BASE
]._ns_main_searchlist
= &main_map
->l_searchlist
;
1982 /* Save the information about the original global scope list since
1983 we need it in the memory handling later. */
1984 GLRO(dl_initial_searchlist
) = *GL(dl_ns
)[LM_ID_BASE
]._ns_main_searchlist
;
1986 /* Remember the last search directory added at startup, now that
1987 malloc will no longer be the one from dl-minimal.c. */
1988 GLRO(dl_init_all_dirs
) = GL(dl_all_dirs
);
1990 /* Print scope information. */
1991 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_SCOPES
))
1993 _dl_debug_printf ("\nInitial object scopes\n");
1995 for (struct link_map
*l
= main_map
; l
!= NULL
; l
= l
->l_next
)
1996 _dl_show_scope (l
, 0);
2001 if (main_map
->l_info
[ADDRIDX (DT_GNU_CONFLICT
)] != NULL
)
2003 ElfW(Rela
) *conflict
, *conflictend
;
2004 #ifndef HP_TIMING_NONAVAIL
2009 HP_TIMING_NOW (start
);
2010 assert (main_map
->l_info
[VALIDX (DT_GNU_CONFLICTSZ
)] != NULL
);
2011 conflict
= (ElfW(Rela
) *)
2012 main_map
->l_info
[ADDRIDX (DT_GNU_CONFLICT
)]->d_un
.d_ptr
;
2013 conflictend
= (ElfW(Rela
) *)
2015 + main_map
->l_info
[VALIDX (DT_GNU_CONFLICTSZ
)]->d_un
.d_val
);
2016 _dl_resolve_conflicts (main_map
, conflict
, conflictend
);
2017 HP_TIMING_NOW (stop
);
2018 HP_TIMING_DIFF (relocate_time
, start
, stop
);
2022 /* Mark all the objects so we know they have been already relocated. */
2023 for (struct link_map
*l
= main_map
; l
!= NULL
; l
= l
->l_next
)
2026 if (l
->l_relro_size
)
2027 _dl_protect_relro (l
);
2029 /* Add object to slot information data if necessasy. */
2030 if (l
->l_tls_blocksize
!= 0 && tls_init_tp_called
)
2031 _dl_add_to_slotinfo (l
);
2036 /* Now we have all the objects loaded. Relocate them all except for
2037 the dynamic linker itself. We do this in reverse order so that copy
2038 relocs of earlier objects overwrite the data written by later
2039 objects. We do not re-relocate the dynamic linker itself in this
2040 loop because that could result in the GOT entries for functions we
2041 call being changed, and that would break us. It is safe to relocate
2042 the dynamic linker out of order because it has no copy relocs (we
2043 know that because it is self-contained). */
2045 int consider_profiling
= GLRO(dl_profile
) != NULL
;
2046 #ifndef HP_TIMING_NONAVAIL
2051 /* If we are profiling we also must do lazy reloaction. */
2052 GLRO(dl_lazy
) |= consider_profiling
;
2054 HP_TIMING_NOW (start
);
2055 unsigned i
= main_map
->l_searchlist
.r_nlist
;
2058 struct link_map
*l
= main_map
->l_initfini
[i
];
2060 /* While we are at it, help the memory handling a bit. We have to
2061 mark some data structures as allocated with the fake malloc()
2062 implementation in ld.so. */
2063 struct libname_list
*lnp
= l
->l_libname
->next
;
2065 while (__builtin_expect (lnp
!= NULL
, 0))
2070 /* Also allocated with the fake malloc(). */
2071 l
->l_free_initfini
= 0;
2073 if (l
!= &GL(dl_rtld_map
))
2074 _dl_relocate_object (l
, l
->l_scope
, GLRO(dl_lazy
) ? RTLD_LAZY
: 0,
2075 consider_profiling
);
2077 /* Add object to slot information data if necessasy. */
2078 if (l
->l_tls_blocksize
!= 0 && tls_init_tp_called
)
2079 _dl_add_to_slotinfo (l
);
2081 HP_TIMING_NOW (stop
);
2083 HP_TIMING_DIFF (relocate_time
, start
, stop
);
2085 /* Now enable profiling if needed. Like the previous call,
2086 this has to go here because the calls it makes should use the
2087 rtld versions of the functions (particularly calloc()), but it
2088 needs to have _dl_profile_map set up by the relocator. */
2089 if (__glibc_unlikely (GL(dl_profile_map
) != NULL
))
2090 /* We must prepare the profiling. */
2091 _dl_start_profile ();
2094 if ((!was_tls_init_tp_called
&& GL(dl_tls_max_dtv_idx
) > 0)
2095 || count_modids
!= _dl_count_modids ())
2096 ++GL(dl_tls_generation
);
2098 /* Now that we have completed relocation, the initializer data
2099 for the TLS blocks has its final values and we can copy them
2100 into the main thread's TLS area, which we allocated above. */
2101 _dl_allocate_tls_init (tcbp
);
2103 /* And finally install it for the main thread. */
2104 if (! tls_init_tp_called
)
2106 const char *lossage
= TLS_INIT_TP (tcbp
);
2107 if (__glibc_unlikely (lossage
!= NULL
))
2108 _dl_fatal_printf ("cannot set up thread-local storage: %s\n",
2112 /* Make sure no new search directories have been added. */
2113 assert (GLRO(dl_init_all_dirs
) == GL(dl_all_dirs
));
2115 if (! prelinked
&& rtld_multiple_ref
)
2117 /* There was an explicit ref to the dynamic linker as a shared lib.
2118 Re-relocate ourselves with user-controlled symbol definitions.
2120 We must do this after TLS initialization in case after this
2121 re-relocation, we might call a user-supplied function
2122 (e.g. calloc from _dl_relocate_object) that uses TLS data. */
2124 #ifndef HP_TIMING_NONAVAIL
2130 HP_TIMING_NOW (start
);
2131 /* Mark the link map as not yet relocated again. */
2132 GL(dl_rtld_map
).l_relocated
= 0;
2133 _dl_relocate_object (&GL(dl_rtld_map
), main_map
->l_scope
, 0, 0);
2134 HP_TIMING_NOW (stop
);
2135 HP_TIMING_DIFF (add
, start
, stop
);
2136 HP_TIMING_ACCUM_NT (relocate_time
, add
);
2139 /* Do any necessary cleanups for the startup OS interface code.
2140 We do these now so that no calls are made after rtld re-relocation
2141 which might be resolved to different functions than we expect.
2142 We cannot do this before relocating the other objects because
2143 _dl_relocate_object might need to call `mprotect' for DT_TEXTREL. */
2144 _dl_sysdep_start_cleanup ();
2147 /* Auditing checkpoint: we have added all objects. */
2148 if (__glibc_unlikely (GLRO(dl_naudit
) > 0))
2150 struct link_map
*head
= GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
;
2151 /* Do not call the functions for any auditing object. */
2152 if (head
->l_auditing
== 0)
2154 struct audit_ifaces
*afct
= GLRO(dl_audit
);
2155 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
2157 if (afct
->activity
!= NULL
)
2158 afct
->activity (&head
->l_audit
[cnt
].cookie
, LA_ACT_CONSISTENT
);
2166 /* Notify the debugger all new objects are now ready to go. We must re-get
2167 the address since by now the variable might be in another object. */
2168 r
= _dl_debug_initialize (0, LM_ID_BASE
);
2169 r
->r_state
= RT_CONSISTENT
;
2171 LIBC_PROBE (init_complete
, 2, LM_ID_BASE
, r
);
2173 #if defined USE_LDCONFIG && !defined MAP_COPY
2174 /* We must munmap() the cache file. */
2175 _dl_unload_cache ();
2178 /* Once we return, _dl_sysdep_start will invoke
2179 the DT_INIT functions and then *USER_ENTRY. */
2182 /* This is a little helper function for resolving symbols while
2183 tracing the binary. */
2185 print_unresolved (int errcode
__attribute__ ((unused
)), const char *objname
,
2186 const char *errstring
)
2188 if (objname
[0] == '\0')
2189 objname
= RTLD_PROGNAME
;
2190 _dl_error_printf ("%s (%s)\n", errstring
, objname
);
2193 /* This is a little helper function for resolving symbols while
2194 tracing the binary. */
2196 print_missing_version (int errcode
__attribute__ ((unused
)),
2197 const char *objname
, const char *errstring
)
2199 _dl_error_printf ("%s: %s: %s\n", RTLD_PROGNAME
,
2200 objname
, errstring
);
2203 /* Nonzero if any of the debugging options is enabled. */
2204 static int any_debug attribute_relro
;
2206 /* Process the string given as the parameter which explains which debugging
2207 options are enabled. */
2209 process_dl_debug (const char *dl_debug
)
2211 /* When adding new entries make sure that the maximal length of a name
2212 is correctly handled in the LD_DEBUG_HELP code below. */
2216 const char name
[10];
2217 const char helptext
[41];
2218 unsigned short int mask
;
2221 #define LEN_AND_STR(str) sizeof (str) - 1, str
2222 { LEN_AND_STR ("libs"), "display library search paths",
2223 DL_DEBUG_LIBS
| DL_DEBUG_IMPCALLS
},
2224 { LEN_AND_STR ("reloc"), "display relocation processing",
2225 DL_DEBUG_RELOC
| DL_DEBUG_IMPCALLS
},
2226 { LEN_AND_STR ("files"), "display progress for input file",
2227 DL_DEBUG_FILES
| DL_DEBUG_IMPCALLS
},
2228 { LEN_AND_STR ("symbols"), "display symbol table processing",
2229 DL_DEBUG_SYMBOLS
| DL_DEBUG_IMPCALLS
},
2230 { LEN_AND_STR ("bindings"), "display information about symbol binding",
2231 DL_DEBUG_BINDINGS
| DL_DEBUG_IMPCALLS
},
2232 { LEN_AND_STR ("versions"), "display version dependencies",
2233 DL_DEBUG_VERSIONS
| DL_DEBUG_IMPCALLS
},
2234 { LEN_AND_STR ("scopes"), "display scope information",
2236 { LEN_AND_STR ("all"), "all previous options combined",
2237 DL_DEBUG_LIBS
| DL_DEBUG_RELOC
| DL_DEBUG_FILES
| DL_DEBUG_SYMBOLS
2238 | DL_DEBUG_BINDINGS
| DL_DEBUG_VERSIONS
| DL_DEBUG_IMPCALLS
2239 | DL_DEBUG_SCOPES
},
2240 { LEN_AND_STR ("statistics"), "display relocation statistics",
2241 DL_DEBUG_STATISTICS
},
2242 { LEN_AND_STR ("unused"), "determined unused DSOs",
2244 { LEN_AND_STR ("help"), "display this help message and exit",
2247 #define ndebopts (sizeof (debopts) / sizeof (debopts[0]))
2249 /* Skip separating white spaces and commas. */
2250 while (*dl_debug
!= '\0')
2252 if (*dl_debug
!= ' ' && *dl_debug
!= ',' && *dl_debug
!= ':')
2257 while (dl_debug
[len
] != '\0' && dl_debug
[len
] != ' '
2258 && dl_debug
[len
] != ',' && dl_debug
[len
] != ':')
2261 for (cnt
= 0; cnt
< ndebopts
; ++cnt
)
2262 if (debopts
[cnt
].len
== len
2263 && memcmp (dl_debug
, debopts
[cnt
].name
, len
) == 0)
2265 GLRO(dl_debug_mask
) |= debopts
[cnt
].mask
;
2270 if (cnt
== ndebopts
)
2272 /* Display a warning and skip everything until next
2274 char *copy
= strndupa (dl_debug
, len
);
2275 _dl_error_printf ("\
2276 warning: debug option `%s' unknown; try LD_DEBUG=help\n", copy
);
2286 if (GLRO(dl_debug_mask
) & DL_DEBUG_UNUSED
)
2288 /* In order to get an accurate picture of whether a particular
2289 DT_NEEDED entry is actually used we have to process both
2290 the PLT and non-PLT relocation entries. */
2294 if (GLRO(dl_debug_mask
) & DL_DEBUG_HELP
)
2299 Valid options for the LD_DEBUG environment variable are:\n\n");
2301 for (cnt
= 0; cnt
< ndebopts
; ++cnt
)
2302 _dl_printf (" %.*s%s%s\n", debopts
[cnt
].len
, debopts
[cnt
].name
,
2303 " " + debopts
[cnt
].len
- 3,
2304 debopts
[cnt
].helptext
);
2307 To direct the debugging output into a file instead of standard output\n\
2308 a filename can be specified using the LD_DEBUG_OUTPUT environment variable.\n");
2314 process_dl_audit (char *str
)
2316 /* The parameter is a colon separated list of DSO names. */
2319 while ((p
= (strsep
) (&str
, ":")) != NULL
)
2321 && (__builtin_expect (! __libc_enable_secure
, 1)
2322 || strchr (p
, '/') == NULL
))
2324 /* This is using the local malloc, not the system malloc. The
2325 memory can never be freed. */
2326 struct audit_list
*newp
= malloc (sizeof (*newp
));
2329 if (audit_list
== NULL
)
2330 audit_list
= newp
->next
= newp
;
2333 newp
->next
= audit_list
->next
;
2334 audit_list
= audit_list
->next
= newp
;
2339 /* Process all environments variables the dynamic linker must recognize.
2340 Since all of them start with `LD_' we are a bit smarter while finding
2342 extern char **_environ attribute_hidden
;
2346 process_envvars (enum mode
*modep
)
2348 char **runp
= _environ
;
2350 enum mode mode
= normal
;
2351 char *debug_output
= NULL
;
2353 /* This is the default place for profiling data file. */
2354 GLRO(dl_profile_output
)
2355 = &"/var/tmp\0/var/profile"[__libc_enable_secure
? 9 : 0];
2357 while ((envline
= _dl_next_ld_env_entry (&runp
)) != NULL
)
2361 while (envline
[len
] != '\0' && envline
[len
] != '=')
2364 if (envline
[len
] != '=')
2365 /* This is a "LD_" variable at the end of the string without
2366 a '=' character. Ignore it since otherwise we will access
2367 invalid memory below. */
2373 /* Warning level, verbose or not. */
2374 if (memcmp (envline
, "WARN", 4) == 0)
2375 GLRO(dl_verbose
) = envline
[5] != '\0';
2379 /* Debugging of the dynamic linker? */
2380 if (memcmp (envline
, "DEBUG", 5) == 0)
2382 process_dl_debug (&envline
[6]);
2385 if (memcmp (envline
, "AUDIT", 5) == 0)
2386 process_dl_audit (&envline
[6]);
2390 /* Print information about versions. */
2391 if (memcmp (envline
, "VERBOSE", 7) == 0)
2393 version_info
= envline
[8] != '\0';
2397 /* List of objects to be preloaded. */
2398 if (memcmp (envline
, "PRELOAD", 7) == 0)
2400 preloadlist
= &envline
[8];
2404 /* Which shared object shall be profiled. */
2405 if (memcmp (envline
, "PROFILE", 7) == 0 && envline
[8] != '\0')
2406 GLRO(dl_profile
) = &envline
[8];
2410 /* Do we bind early? */
2411 if (memcmp (envline
, "BIND_NOW", 8) == 0)
2413 GLRO(dl_lazy
) = envline
[9] == '\0';
2416 if (memcmp (envline
, "BIND_NOT", 8) == 0)
2417 GLRO(dl_bind_not
) = envline
[9] != '\0';
2421 /* Test whether we want to see the content of the auxiliary
2422 array passed up from the kernel. */
2423 if (!__libc_enable_secure
2424 && memcmp (envline
, "SHOW_AUXV", 9) == 0)
2429 /* Mask for the important hardware capabilities. */
2430 if (memcmp (envline
, "HWCAP_MASK", 10) == 0)
2431 GLRO(dl_hwcap_mask
) = __strtoul_internal (&envline
[11], NULL
,
2436 /* Path where the binary is found. */
2437 if (!__libc_enable_secure
2438 && memcmp (envline
, "ORIGIN_PATH", 11) == 0)
2439 GLRO(dl_origin_path
) = &envline
[12];
2443 /* The library search path. */
2444 if (memcmp (envline
, "LIBRARY_PATH", 12) == 0)
2446 library_path
= &envline
[13];
2450 /* Where to place the profiling data file. */
2451 if (memcmp (envline
, "DEBUG_OUTPUT", 12) == 0)
2453 debug_output
= &envline
[13];
2457 if (!__libc_enable_secure
2458 && memcmp (envline
, "DYNAMIC_WEAK", 12) == 0)
2459 GLRO(dl_dynamic_weak
) = 1;
2463 /* We might have some extra environment variable with length 13
2465 #ifdef EXTRA_LD_ENVVARS_13
2468 if (!__libc_enable_secure
2469 && memcmp (envline
, "USE_LOAD_BIAS", 13) == 0)
2471 GLRO(dl_use_load_bias
) = envline
[14] == '1' ? -1 : 0;
2475 if (memcmp (envline
, "POINTER_GUARD", 13) == 0)
2476 GLRO(dl_pointer_guard
) = envline
[14] != '0';
2480 /* Where to place the profiling data file. */
2481 if (!__libc_enable_secure
2482 && memcmp (envline
, "PROFILE_OUTPUT", 14) == 0
2483 && envline
[15] != '\0')
2484 GLRO(dl_profile_output
) = &envline
[15];
2488 /* The mode of the dynamic linker can be set. */
2489 if (memcmp (envline
, "TRACE_PRELINKING", 16) == 0)
2492 GLRO(dl_verbose
) = 1;
2493 GLRO(dl_debug_mask
) |= DL_DEBUG_PRELINK
;
2494 GLRO(dl_trace_prelink
) = &envline
[17];
2499 /* The mode of the dynamic linker can be set. */
2500 if (memcmp (envline
, "TRACE_LOADED_OBJECTS", 20) == 0)
2504 /* We might have some extra environment variable to handle. This
2505 is tricky due to the pre-processing of the length of the name
2506 in the switch statement here. The code here assumes that added
2507 environment variables have a different length. */
2508 #ifdef EXTRA_LD_ENVVARS
2514 /* The caller wants this information. */
2517 /* Extra security for SUID binaries. Remove all dangerous environment
2519 if (__builtin_expect (__libc_enable_secure
, 0))
2521 static const char unsecure_envvars
[] =
2522 #ifdef EXTRA_UNSECURE_ENVVARS
2523 EXTRA_UNSECURE_ENVVARS
2528 nextp
= unsecure_envvars
;
2532 /* We could use rawmemchr but this need not be fast. */
2533 nextp
= (char *) (strchr
) (nextp
, '\0') + 1;
2535 while (*nextp
!= '\0');
2537 if (__access ("/etc/suid-debug", F_OK
) != 0)
2539 unsetenv ("MALLOC_CHECK_");
2540 GLRO(dl_debug_mask
) = 0;
2546 /* If we have to run the dynamic linker in debugging mode and the
2547 LD_DEBUG_OUTPUT environment variable is given, we write the debug
2548 messages to this file. */
2549 else if (any_debug
&& debug_output
!= NULL
)
2552 const int flags
= O_WRONLY
| O_APPEND
| O_CREAT
| O_NOFOLLOW
;
2554 const int flags
= O_WRONLY
| O_APPEND
| O_CREAT
;
2556 size_t name_len
= strlen (debug_output
);
2557 char buf
[name_len
+ 12];
2560 buf
[name_len
+ 11] = '\0';
2561 startp
= _itoa (__getpid (), &buf
[name_len
+ 11], 10, 0);
2563 startp
= memcpy (startp
- name_len
, debug_output
, name_len
);
2565 GLRO(dl_debug_fd
) = __open (startp
, flags
, DEFFILEMODE
);
2566 if (GLRO(dl_debug_fd
) == -1)
2567 /* We use standard output if opening the file failed. */
2568 GLRO(dl_debug_fd
) = STDOUT_FILENO
;
2573 /* Print the various times we collected. */
2575 __attribute ((noinline
))
2576 print_statistics (hp_timing_t
*rtld_total_timep
)
2578 #ifndef HP_TIMING_NONAVAIL
2583 /* Total time rtld used. */
2584 if (HP_SMALL_TIMING_AVAIL
)
2586 HP_TIMING_PRINT (buf
, sizeof (buf
), *rtld_total_timep
);
2587 _dl_debug_printf ("\nruntime linker statistics:\n"
2588 " total startup time in dynamic loader: %s\n", buf
);
2590 /* Print relocation statistics. */
2592 HP_TIMING_PRINT (buf
, sizeof (buf
), relocate_time
);
2593 cp
= _itoa ((1000ULL * relocate_time
) / *rtld_total_timep
,
2594 pbuf
+ sizeof (pbuf
), 10, 0);
2596 switch (pbuf
+ sizeof (pbuf
) - cp
)
2607 _dl_debug_printf ("\
2608 time needed for relocation: %s (%s%%)\n", buf
, pbuf
);
2612 unsigned long int num_relative_relocations
= 0;
2613 for (Lmid_t ns
= 0; ns
< GL(dl_nns
); ++ns
)
2615 if (GL(dl_ns
)[ns
]._ns_loaded
== NULL
)
2618 struct r_scope_elem
*scope
= &GL(dl_ns
)[ns
]._ns_loaded
->l_searchlist
;
2620 for (unsigned int i
= 0; i
< scope
->r_nlist
; i
++)
2622 struct link_map
*l
= scope
->r_list
[i
];
2624 if (l
->l_addr
!= 0 && l
->l_info
[VERSYMIDX (DT_RELCOUNT
)])
2625 num_relative_relocations
2626 += l
->l_info
[VERSYMIDX (DT_RELCOUNT
)]->d_un
.d_val
;
2627 #ifndef ELF_MACHINE_REL_RELATIVE
2628 /* Relative relocations are processed on these architectures if
2629 library is loaded to different address than p_vaddr or
2630 if not prelinked. */
2631 if ((l
->l_addr
!= 0 || !l
->l_info
[VALIDX(DT_GNU_PRELINKED
)])
2632 && l
->l_info
[VERSYMIDX (DT_RELACOUNT
)])
2634 /* On e.g. IA-64 or Alpha, relative relocations are processed
2635 only if library is loaded to different address than p_vaddr. */
2636 if (l
->l_addr
!= 0 && l
->l_info
[VERSYMIDX (DT_RELACOUNT
)])
2638 num_relative_relocations
2639 += l
->l_info
[VERSYMIDX (DT_RELACOUNT
)]->d_un
.d_val
;
2643 _dl_debug_printf (" number of relocations: %lu\n"
2644 " number of relocations from cache: %lu\n"
2645 " number of relative relocations: %lu\n",
2646 GL(dl_num_relocations
),
2647 GL(dl_num_cache_relocations
),
2648 num_relative_relocations
);
2650 #ifndef HP_TIMING_NONAVAIL
2651 /* Time spend while loading the object and the dependencies. */
2652 if (HP_SMALL_TIMING_AVAIL
)
2655 HP_TIMING_PRINT (buf
, sizeof (buf
), load_time
);
2656 cp
= _itoa ((1000ULL * load_time
) / *rtld_total_timep
,
2657 pbuf
+ sizeof (pbuf
), 10, 0);
2659 switch (pbuf
+ sizeof (pbuf
) - cp
)
2670 _dl_debug_printf ("\
2671 time needed to load objects: %s (%s%%)\n",