1 /* Run time dynamic linker.
2 Copyright (C) 1995-1999, 2000, 2001, 2002 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, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
26 #include <sys/mman.h> /* Check if MAP_ANON is defined. */
27 #include <sys/param.h>
30 #include <stdio-common/_itoa.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-procinfo.h>
43 /* Helper function to handle errors while resolving symbols. */
44 static void print_unresolved (int errcode
, const char *objname
,
45 const char *errsting
);
47 /* Helper function to handle errors when a version is missing. */
48 static void print_missing_version (int errcode
, const char *objname
,
49 const char *errsting
);
51 /* Print the various times we collected. */
52 static void print_statistics (void);
54 /* This is a list of all the modes the dynamic loader can be in. */
55 enum mode
{ normal
, list
, verify
, trace
};
57 /* Process all environments variables the dynamic linker must recognize.
58 Since all of them start with `LD_' we are a bit smarter while finding
60 static void process_envvars (enum mode
*modep
);
62 int _dl_argc attribute_hidden
;
63 char **_dl_argv
= NULL
;
66 /* Nonzero if we were run directly. */
67 unsigned int _dl_skip_args attribute_hidden
;
69 /* Set nonzero during loading and initialization of executable and
70 libraries, cleared before the executable's entry point runs. This
71 must not be initialized to nonzero, because the unused dynamic
72 linker loaded in for libc.so's "ld.so.1" dep will provide the
73 definition seen by libc.so's initializer; that value must be zero,
74 and will be since that dynamic linker's _dl_start and dl_main will
76 int _dl_starting_up
= 0;
77 INTVARDEF(_dl_starting_up
)
79 /* This is the structure which defines all variables global to ld.so
80 (except those which cannot be added for some reason). */
81 struct rtld_global _rtld_global
=
83 /* Get architecture specific initializer. */
84 #include <dl-procinfo.c>
85 ._dl_debug_fd
= STDERR_FILENO
,
87 /* XXX I know about at least one case where we depend on the old
88 weak behavior (it has to do with librt). Until we get DSO
89 groups implemented we have to make this the default.
91 ._dl_dynamic_weak
= 1,
94 ._dl_fpu_control
= _FPU_DEFAULT
,
95 ._dl_correct_cache_id
= _DL_CACHE_DEFAULT_ID
,
96 ._dl_hwcap_mask
= HWCAP_IMPORTANT
,
97 ._dl_load_lock
= _LIBC_LOCK_RECURSIVE_INITIALIZER
99 strong_alias (_rtld_global
, _rtld_local
);
101 static void dl_main (const ElfW(Phdr
) *phdr
, ElfW(Word
) phnum
,
102 ElfW(Addr
) *user_entry
);
104 static struct libname_list _dl_rtld_libname
;
105 static struct libname_list _dl_rtld_libname2
;
107 /* We expect less than a second for relocation. */
108 #ifdef HP_SMALL_TIMING_AVAIL
109 # undef HP_TIMING_AVAIL
110 # define HP_TIMING_AVAIL HP_SMALL_TIMING_AVAIL
113 /* Variable for statistics. */
114 #ifndef HP_TIMING_NONAVAIL
115 static hp_timing_t rtld_total_time
;
116 static hp_timing_t relocate_time
;
117 static hp_timing_t load_time
;
118 static hp_timing_t start_time
;
121 /* Additional definitions needed by TLS initialization. */
122 #ifdef TLS_INIT_HELPER
126 /* Before ld.so is relocated we must not access variables which need
127 relocations. This means variables which are exported. Variables
128 declared as static are fine. If we can mark a variable hidden this
129 is fine, too. The latter is impotant here. We can avoid setting
130 up a temporary link map for ld.so if we can mark _rtld_global as
132 #if defined PI_STATIC_AND_HIDDEN && defined HAVE_HIDDEN \
133 && defined HAVE_VISIBILITY_ATTRIBUTE
134 # define DONT_USE_BOOTSTRAP_MAP 1
137 #ifdef DONT_USE_BOOTSTRAP_MAP
138 static ElfW(Addr
) _dl_start_final (void *arg
);
140 static ElfW(Addr
) _dl_start_final (void *arg
,
141 struct link_map
*bootstrap_map_p
);
147 # error "sysdeps/MACHINE/dl-machine.h fails to define RTLD_START"
151 # define VALIDX(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
152 + DT_EXTRANUM + DT_VALTAGIDX (tag))
155 # define ADDRIDX(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
156 + DT_EXTRANUM + DT_VALNUM + DT_ADDRTAGIDX (tag))
159 /* This is the second half of _dl_start (below). It can be inlined safely
160 under DONT_USE_BOOTSTRAP_MAP, where it is careful not to make any GOT
161 references. When the tools don't permit us to avoid using a GOT entry
162 for _dl_rtld_global (no attribute_hidden support), we must make sure
163 this function is not inlined (see below). */
165 #ifdef DONT_USE_BOOTSTRAP_MAP
166 static inline ElfW(Addr
) __attribute__ ((always_inline
))
167 _dl_start_final (void *arg
)
169 static ElfW(Addr
) __attribute__ ((noinline
))
170 _dl_start_final (void *arg
, struct link_map
*bootstrap_map_p
)
173 ElfW(Addr
) start_addr
;
174 extern char _begin
[] attribute_hidden
;
175 extern char _end
[] attribute_hidden
;
179 /* If it hasn't happen yet record the startup time. */
180 if (! HP_TIMING_INLINE
)
181 HP_TIMING_NOW (start_time
);
183 /* Initialize the timing functions. */
184 HP_TIMING_DIFF_INIT ();
187 /* Transfer data about ourselves to the permanent link_map structure. */
188 #ifndef DONT_USE_BOOTSTRAP_MAP
189 GL(dl_rtld_map
).l_addr
= bootstrap_map_p
->l_addr
;
190 GL(dl_rtld_map
).l_ld
= bootstrap_map_p
->l_ld
;
191 memcpy (GL(dl_rtld_map
).l_info
, bootstrap_map_p
->l_info
,
192 sizeof GL(dl_rtld_map
).l_info
);
193 GL(dl_rtld_map
).l_mach
= bootstrap_map_p
->l_mach
;
195 _dl_setup_hash (&GL(dl_rtld_map
));
196 GL(dl_rtld_map
).l_opencount
= 1;
197 GL(dl_rtld_map
).l_map_start
= (ElfW(Addr
)) _begin
;
198 GL(dl_rtld_map
).l_map_end
= (ElfW(Addr
)) _end
;
199 /* Copy the TLS related data if necessary. */
200 #if USE_TLS && !defined DONT_USE_BOOTSTRAP_MAP
201 # ifdef HAVE___THREAD
202 assert (bootstrap_map_p
->l_tls_modid
!= 0);
204 if (bootstrap_map_p
->l_tls_modid
!= 0)
207 GL(dl_rtld_map
).l_tls_blocksize
= bootstrap_map_p
->l_tls_blocksize
;
208 GL(dl_rtld_map
).l_tls_align
= bootstrap_map_p
->l_tls_align
;
209 GL(dl_rtld_map
).l_tls_initimage_size
210 = bootstrap_map_p
->l_tls_initimage_size
;
211 GL(dl_rtld_map
).l_tls_initimage
= bootstrap_map_p
->l_tls_initimage
;
212 GL(dl_rtld_map
).l_tls_offset
= bootstrap_map_p
->l_tls_offset
;
213 GL(dl_rtld_map
).l_tls_modid
= 1;
214 GL(dl_rtld_map
).l_tls_tp_initialized
215 = bootstrap_map_p
->l_tls_tp_initialized
;
220 HP_TIMING_NOW (GL(dl_cpuclock_offset
));
223 /* Call the OS-dependent function to set up life so we can do things like
224 file access. It will call `dl_main' (below) to do all the real work
225 of the dynamic linker, and then unwind our frame and run the user
226 entry point on the same stack we entered on. */
227 start_addr
= _dl_sysdep_start (arg
, &dl_main
);
229 #ifndef HP_TIMING_NONAVAIL
232 hp_timing_t end_time
;
234 /* Get the current time. */
235 HP_TIMING_NOW (end_time
);
237 /* Compute the difference. */
238 HP_TIMING_DIFF (rtld_total_time
, start_time
, end_time
);
242 if (__builtin_expect (GL(dl_debug_mask
) & DL_DEBUG_STATISTICS
, 0))
248 static ElfW(Addr
) __attribute_used__ internal_function
249 _dl_start (void *arg
)
251 #ifdef DONT_USE_BOOTSTRAP_MAP
252 # define bootstrap_map GL(dl_rtld_map)
254 struct link_map bootstrap_map
;
256 #if !defined HAVE_BUILTIN_MEMSET || defined USE_TLS
265 /* This #define produces dynamic linking inline functions for
266 bootstrap relocation instead of general-purpose relocation. */
267 #define RTLD_BOOTSTRAP
268 #define RESOLVE_MAP(sym, version, flags) \
269 ((*(sym))->st_shndx == SHN_UNDEF ? 0 : &bootstrap_map)
270 #define RESOLVE(sym, version, flags) \
271 ((*(sym))->st_shndx == SHN_UNDEF ? 0 : bootstrap_map.l_addr)
272 #include "dynamic-link.h"
274 if (HP_TIMING_INLINE
&& HP_TIMING_AVAIL
)
275 HP_TIMING_NOW (start_time
);
277 /* Partly clean the `bootstrap_map' structure up. Don't use
278 `memset' since it might not be built in or inlined and we cannot
279 make function calls at this point. Use '__builtin_memset' if we
280 know it is available. We do not have to clear the memory if we
281 do not have to use the temporary bootstrap_map. Global variables
282 are initialized to zero by default. */
283 #ifndef DONT_USE_BOOTSTRAP_MAP
284 # ifdef HAVE_BUILTIN_MEMSET
285 __builtin_memset (bootstrap_map
.l_info
, '\0', sizeof (bootstrap_map
.l_info
));
288 cnt
< sizeof (bootstrap_map
.l_info
) / sizeof (bootstrap_map
.l_info
[0]);
290 bootstrap_map
.l_info
[cnt
] = 0;
294 /* Figure out the run-time load address of the dynamic linker itself. */
295 bootstrap_map
.l_addr
= elf_machine_load_address ();
297 /* Read our own dynamic section and fill in the info array. */
298 bootstrap_map
.l_ld
= (void *) bootstrap_map
.l_addr
+ elf_machine_dynamic ();
299 elf_get_dynamic_info (&bootstrap_map
);
302 # if !defined HAVE___THREAD && !defined DONT_USE_BOOTSTRAP_MAP
303 /* Signal that we have not found TLS data so far. */
304 bootstrap_map
.l_tls_modid
= 0;
307 /* Get the dynamic linkers program header. */
308 ehdr
= (ElfW(Ehdr
) *) bootstrap_map
.l_addr
;
309 phdr
= (ElfW(Phdr
) *) (bootstrap_map
.l_addr
+ ehdr
->e_phoff
);
310 for (cnt
= 0; cnt
< ehdr
->e_phnum
; ++cnt
)
311 if (phdr
[cnt
].p_type
== PT_TLS
)
314 size_t max_align
= MAX (TLS_INIT_TCB_ALIGN
, phdr
[cnt
].p_align
);
317 bootstrap_map
.l_tls_blocksize
= phdr
[cnt
].p_memsz
;
318 bootstrap_map
.l_tls_align
= phdr
[cnt
].p_align
;
319 assert (bootstrap_map
.l_tls_blocksize
!= 0);
320 bootstrap_map
.l_tls_initimage_size
= phdr
[cnt
].p_filesz
;
321 bootstrap_map
.l_tls_initimage
= (void *) (bootstrap_map
.l_addr
322 + phdr
[cnt
].p_vaddr
);
324 /* We can now allocate the initial TLS block. This can happen
325 on the stack. We'll get the final memory later when we
326 know all about the various objects loaded at startup
329 tlsblock
= alloca (roundup (bootstrap_map
.l_tls_blocksize
,
334 tlsblock
= alloca (roundup (TLS_INIT_TCB_SIZE
,
335 bootstrap_map
.l_tls_align
)
336 + bootstrap_map
.l_tls_blocksize
339 /* In case a model with a different layout for the TCB and DTV
340 is defined add another #elif here and in the following #ifs. */
341 # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
343 /* Align the TLS block. */
344 tlsblock
= (void *) (((uintptr_t) tlsblock
+ max_align
- 1)
347 /* Initialize the dtv. [0] is the length, [1] the generation
349 initdtv
[0].counter
= 1;
350 initdtv
[1].counter
= 0;
352 /* Initialize the TLS block. */
354 initdtv
[2].pointer
= tlsblock
;
356 bootstrap_map
.l_tls_offset
= roundup (TLS_INIT_TCB_SIZE
,
357 bootstrap_map
.l_tls_align
);
358 initdtv
[2].pointer
= (char *) tlsblock
+ bootstrap_map
.l_tls_offset
;
360 # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
362 p
= __mempcpy (initdtv
[2].pointer
, bootstrap_map
.l_tls_initimage
,
363 bootstrap_map
.l_tls_initimage_size
);
364 # ifdef HAVE_BUILTIN_MEMSET
365 __builtin_memset (p
, '\0', (bootstrap_map
.l_tls_blocksize
366 - bootstrap_map
.l_tls_initimage_size
));
369 size_t remaining
= (bootstrap_map
.l_tls_blocksize
370 - bootstrap_map
.l_tls_initimage_size
);
371 while (remaining
-- > 0)
376 /* Install the pointer to the dtv. */
378 /* Initialize the thread pointer. */
380 bootstrap_map
.l_tls_offset
381 = roundup (bootstrap_map
.l_tls_blocksize
, TLS_INIT_TCB_ALIGN
);
383 INSTALL_DTV ((char *) tlsblock
+ bootstrap_map
.l_tls_offset
,
386 if (TLS_INIT_TP ((char *) tlsblock
+ bootstrap_map
.l_tls_offset
, 0)
388 _dl_fatal_printf ("cannot setup thread-local storage\n");
390 INSTALL_DTV (tlsblock
, initdtv
);
391 if (TLS_INIT_TP (tlsblock
, 0) != 0)
392 _dl_fatal_printf ("cannot setup thread-local storage\n");
394 # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
397 /* So far this is module number one. */
398 bootstrap_map
.l_tls_modid
= 1;
399 /* The TP got initialized. */
400 bootstrap_map
.l_tls_tp_initialized
= 1;
402 /* There can only be one PT_TLS entry. */
407 #ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
408 ELF_MACHINE_BEFORE_RTLD_RELOC (bootstrap_map
.l_info
);
411 if (bootstrap_map
.l_addr
|| ! bootstrap_map
.l_info
[VALIDX(DT_GNU_PRELINKED
)])
413 /* Relocate ourselves so we can do normal function calls and
414 data access using the global offset table. */
416 ELF_DYNAMIC_RELOCATE (&bootstrap_map
, 0, 0);
419 /* Please note that we don't allow profiling of this object and
420 therefore need not test whether we have to allocate the array
421 for the relocation results (as done in dl-reloc.c). */
423 /* Now life is sane; we can call functions and access global data.
424 Set up to use the operating system facilities, and find out from
425 the operating system's program loader where to find the program
426 header table in core. Put the rest of _dl_start into a separate
427 function, that way the compiler cannot put accesses to the GOT
428 before ELF_DYNAMIC_RELOCATE. */
430 #ifdef DONT_USE_BOOTSTRAP_MAP
431 ElfW(Addr
) entry
= _dl_start_final (arg
);
433 ElfW(Addr
) entry
= _dl_start_final (arg
, &bootstrap_map
);
436 #ifndef ELF_MACHINE_START_ADDRESS
437 # define ELF_MACHINE_START_ADDRESS(map, start) (start)
440 return ELF_MACHINE_START_ADDRESS (GL(dl_loaded
), entry
);
446 /* Now life is peachy; we can do all normal operations.
447 On to the real work. */
449 /* Some helper functions. */
451 /* Arguments to relocate_doit. */
460 /* Argument to map_doit. */
462 /* Return value of map_doit. */
463 struct link_map
*main_map
;
466 /* Arguments to version_check_doit. */
467 struct version_check_args
474 relocate_doit (void *a
)
476 struct relocate_args
*args
= (struct relocate_args
*) a
;
478 INTUSE(_dl_relocate_object
) (args
->l
, args
->l
->l_scope
, args
->lazy
, 0);
484 struct map_args
*args
= (struct map_args
*) a
;
485 args
->main_map
= INTUSE(_dl_map_object
) (NULL
, args
->str
, 0, lt_library
, 0, 0);
489 version_check_doit (void *a
)
491 struct version_check_args
*args
= (struct version_check_args
*) a
;
492 if (_dl_check_all_versions (GL(dl_loaded
), 1, args
->dotrace
) && args
->doexit
)
493 /* We cannot start the application. Abort now. */
498 static inline struct link_map
*
499 find_needed (const char *name
)
501 unsigned int n
= GL(dl_loaded
)->l_searchlist
.r_nlist
;
504 if (_dl_name_match_p (name
, GL(dl_loaded
)->l_searchlist
.r_list
[n
]))
505 return GL(dl_loaded
)->l_searchlist
.r_list
[n
];
507 /* Should never happen. */
512 match_version (const char *string
, struct link_map
*map
)
514 const char *strtab
= (const void *) D_PTR (map
, l_info
[DT_STRTAB
]);
517 #define VERDEFTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERDEF))
518 if (map
->l_info
[VERDEFTAG
] == NULL
)
519 /* The file has no symbol versioning. */
522 def
= (ElfW(Verdef
) *) ((char *) map
->l_addr
523 + map
->l_info
[VERDEFTAG
]->d_un
.d_ptr
);
526 ElfW(Verdaux
) *aux
= (ElfW(Verdaux
) *) ((char *) def
+ def
->vd_aux
);
528 /* Compare the version strings. */
529 if (strcmp (string
, strtab
+ aux
->vda_name
) == 0)
533 /* If no more definitions we failed to find what we want. */
534 if (def
->vd_next
== 0)
537 /* Next definition. */
538 def
= (ElfW(Verdef
) *) ((char *) def
+ def
->vd_next
);
544 static const char *library_path
; /* The library search path. */
545 static const char *preloadlist
; /* The list preloaded objects. */
546 static int version_info
; /* Nonzero if information about
547 versions has to be printed. */
550 dl_main (const ElfW(Phdr
) *phdr
,
552 ElfW(Addr
) *user_entry
)
554 const ElfW(Phdr
) *ph
;
556 struct link_map
**preloads
;
557 unsigned int npreloads
;
560 bool has_interp
= false;
562 bool prelinked
= false;
563 bool rtld_is_main
= false;
564 #ifndef HP_TIMING_NONAVAIL
573 /* Process the environment variable which control the behaviour. */
574 process_envvars (&mode
);
576 /* Set up a flag which tells we are just starting. */
577 INTUSE(_dl_starting_up
) = 1;
579 if (*user_entry
== (ElfW(Addr
)) ENTRY_POINT
)
581 /* Ho ho. We are not the program interpreter! We are the program
582 itself! This means someone ran ld.so as a command. Well, that
583 might be convenient to do sometimes. We support it by
584 interpreting the args like this:
586 ld.so PROGRAM ARGS...
588 The first argument is the name of a file containing an ELF
589 executable we will load and run with the following arguments.
590 To simplify life here, PROGRAM is searched for using the
591 normal rules for shared objects, rather than $PATH or anything
592 like that. We just load it and use its entry point; we don't
593 pay attention to its PT_INTERP command (we are the interpreter
594 ourselves). This is an easy way to test a new ld.so before
598 /* Note the place where the dynamic linker actually came from. */
599 GL(dl_rtld_map
).l_name
= rtld_progname
;
602 if (! strcmp (INTUSE(_dl_argv
)[1], "--list"))
605 GL(dl_lazy
) = -1; /* This means do no dependency analysis. */
611 else if (! strcmp (INTUSE(_dl_argv
)[1], "--verify"))
619 else if (! strcmp (INTUSE(_dl_argv
)[1], "--library-path")
622 library_path
= INTUSE(_dl_argv
)[2];
626 INTUSE(_dl_argv
) += 2;
628 else if (! strcmp (INTUSE(_dl_argv
)[1], "--inhibit-rpath")
631 GL(dl_inhibit_rpath
) = INTUSE(_dl_argv
)[2];
635 INTUSE(_dl_argv
) += 2;
640 /* If we have no further argument the program was called incorrectly.
641 Grant the user some education. */
644 Usage: ld.so [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\
645 You have invoked `ld.so', the helper program for shared library executables.\n\
646 This program usually lives in the file `/lib/ld.so', and special directives\n\
647 in executable files using ELF shared libraries tell the system's program\n\
648 loader to load the helper program from this file. This helper program loads\n\
649 the shared libraries needed by the program executable, prepares the program\n\
650 to run, and runs it. You may invoke this helper program directly from the\n\
651 command line to load and run an ELF executable file; this is like executing\n\
652 that file itself, but always uses this helper program from the file you\n\
653 specified, instead of the helper program file specified in the executable\n\
654 file you run. This is mostly of use for maintainers to test new versions\n\
655 of this helper program; chances are you did not intend to run this program.\n\
657 --list list all dependencies and how they are resolved\n\
658 --verify verify that given object really is a dynamically linked\n\
659 object we can handle\n\
660 --library-path PATH use given PATH instead of content of the environment\n\
661 variable LD_LIBRARY_PATH\n\
662 --inhibit-rpath LIST ignore RUNPATH and RPATH information in object names\n\
669 /* Initialize the data structures for the search paths for shared
671 _dl_init_paths (library_path
);
673 if (__builtin_expect (mode
, normal
) == verify
)
676 const char *err_str
= NULL
;
677 struct map_args args
;
679 args
.str
= rtld_progname
;
680 (void) INTUSE(_dl_catch_error
) (&objname
, &err_str
, map_doit
, &args
);
681 if (__builtin_expect (err_str
!= NULL
, 0))
682 /* We don't free the returned string, the programs stops
684 _exit (EXIT_FAILURE
);
688 HP_TIMING_NOW (start
);
689 INTUSE(_dl_map_object
) (NULL
, rtld_progname
, 0, lt_library
, 0, 0);
690 HP_TIMING_NOW (stop
);
692 HP_TIMING_DIFF (load_time
, start
, stop
);
695 phdr
= GL(dl_loaded
)->l_phdr
;
696 phnum
= GL(dl_loaded
)->l_phnum
;
697 /* We overwrite here a pointer to a malloc()ed string. But since
698 the malloc() implementation used at this point is the dummy
699 implementations which has no real free() function it does not
700 makes sense to free the old string first. */
701 GL(dl_loaded
)->l_name
= (char *) "";
702 *user_entry
= GL(dl_loaded
)->l_entry
;
706 /* Create a link_map for the executable itself.
707 This will be what dlopen on "" returns. */
708 _dl_new_object ((char *) "", "", lt_executable
, NULL
);
709 if (GL(dl_loaded
) == NULL
)
710 _dl_fatal_printf ("cannot allocate memory for link map\n");
711 GL(dl_loaded
)->l_phdr
= phdr
;
712 GL(dl_loaded
)->l_phnum
= phnum
;
713 GL(dl_loaded
)->l_entry
= *user_entry
;
715 /* At this point we are in a bit of trouble. We would have to
716 fill in the values for l_dev and l_ino. But in general we
717 do not know where the file is. We also do not handle AT_EXECFD
718 even if it would be passed up.
720 We leave the values here defined to 0. This is normally no
721 problem as the program code itself is normally no shared
722 object and therefore cannot be loaded dynamically. Nothing
723 prevent the use of dynamic binaries and in these situations
724 we might get problems. We might not be able to find out
725 whether the object is already loaded. But since there is no
726 easy way out and because the dynamic binary must also not
727 have an SONAME we ignore this program for now. If it becomes
728 a problem we can force people using SONAMEs. */
730 /* We delay initializing the path structure until we got the dynamic
731 information for the program. */
734 GL(dl_loaded
)->l_map_end
= 0;
735 /* Perhaps the executable has no PT_LOAD header entries at all. */
736 GL(dl_loaded
)->l_map_start
= ~0;
737 /* We opened the file, account for it. */
738 ++GL(dl_loaded
)->l_opencount
;
740 /* Scan the program header table for the dynamic section. */
741 for (ph
= phdr
; ph
< &phdr
[phnum
]; ++ph
)
745 /* Find out the load address. */
746 GL(dl_loaded
)->l_addr
= (ElfW(Addr
)) phdr
- ph
->p_vaddr
;
749 /* This tells us where to find the dynamic section,
750 which tells us everything we need to do. */
751 GL(dl_loaded
)->l_ld
= (void *) GL(dl_loaded
)->l_addr
+ ph
->p_vaddr
;
754 /* This "interpreter segment" was used by the program loader to
755 find the program interpreter, which is this program itself, the
756 dynamic linker. We note what name finds us, so that a future
757 dlopen call or DT_NEEDED entry, for something that wants to link
758 against the dynamic linker as a shared library, will know that
759 the shared object is already loaded. */
760 _dl_rtld_libname
.name
= ((const char *) GL(dl_loaded
)->l_addr
762 /* _dl_rtld_libname.next = NULL; Already zero. */
763 GL(dl_rtld_map
).l_libname
= &_dl_rtld_libname
;
765 /* Ordinarilly, we would get additional names for the loader from
766 our DT_SONAME. This can't happen if we were actually linked as
767 a static executable (detect this case when we have no DYNAMIC).
768 If so, assume the filename component of the interpreter path to
769 be our SONAME, and add it to our name list. */
770 if (GL(dl_rtld_map
).l_ld
== NULL
)
772 const char *p
= NULL
;
773 const char *cp
= _dl_rtld_libname
.name
;
775 /* Find the filename part of the path. */
782 _dl_rtld_libname2
.name
= p
;
783 /* _dl_rtld_libname2.next = NULL; Already zero. */
784 _dl_rtld_libname
.next
= &_dl_rtld_libname2
;
795 /* Remember where the main program starts in memory. */
796 mapstart
= (GL(dl_loaded
)->l_addr
797 + (ph
->p_vaddr
& ~(ph
->p_align
- 1)));
798 if (GL(dl_loaded
)->l_map_start
> mapstart
)
799 GL(dl_loaded
)->l_map_start
= mapstart
;
801 /* Also where it ends. */
802 allocend
= GL(dl_loaded
)->l_addr
+ ph
->p_vaddr
+ ph
->p_memsz
;
803 if (GL(dl_loaded
)->l_map_end
< allocend
)
804 GL(dl_loaded
)->l_map_end
= allocend
;
811 /* Note that in the case the dynamic linker we duplicate work
812 here since we read the PT_TLS entry already in
813 _dl_start_final. But the result is repeatable so do not
814 check for this special but unimportant case. */
815 GL(dl_loaded
)->l_tls_blocksize
= ph
->p_memsz
;
816 GL(dl_loaded
)->l_tls_align
= ph
->p_align
;
817 GL(dl_loaded
)->l_tls_initimage_size
= ph
->p_filesz
;
818 GL(dl_loaded
)->l_tls_initimage
= (void *) ph
->p_vaddr
;
820 /* This image gets the ID one. */
821 GL(dl_tls_max_dtv_idx
) = GL(dl_loaded
)->l_tls_modid
= 1;
826 if (! GL(dl_loaded
)->l_map_end
)
827 GL(dl_loaded
)->l_map_end
= ~0;
828 if (! GL(dl_rtld_map
).l_libname
&& GL(dl_rtld_map
).l_name
)
830 /* We were invoked directly, so the program might not have a
832 _dl_rtld_libname
.name
= GL(dl_rtld_map
).l_name
;
833 /* _dl_rtld_libname.next = NULL; Already zero. */
834 GL(dl_rtld_map
).l_libname
= &_dl_rtld_libname
;
837 assert (GL(dl_rtld_map
).l_libname
); /* How else did we get here? */
841 /* Extract the contents of the dynamic section for easy access. */
842 elf_get_dynamic_info (GL(dl_loaded
));
843 if (GL(dl_loaded
)->l_info
[DT_HASH
])
844 /* Set up our cache of pointers into the hash table. */
845 _dl_setup_hash (GL(dl_loaded
));
848 if (__builtin_expect (mode
, normal
) == verify
)
850 /* We were called just to verify that this is a dynamic
851 executable using us as the program interpreter. Exit with an
852 error if we were not able to load the binary or no interpreter
853 is specified (i.e., this is no dynamically linked binary. */
854 if (GL(dl_loaded
)->l_ld
== NULL
)
857 /* We allow here some platform specific code. */
858 #ifdef DISTINGUISH_LIB_VERSIONS
859 DISTINGUISH_LIB_VERSIONS
;
861 _exit (has_interp
? 0 : 2);
865 /* Initialize the data structures for the search paths for shared
867 _dl_init_paths (library_path
);
869 /* Put the link_map for ourselves on the chain so it can be found by
870 name. Note that at this point the global chain of link maps contains
871 exactly one element, which is pointed to by dl_loaded. */
872 if (! GL(dl_rtld_map
).l_name
)
873 /* If not invoked directly, the dynamic linker shared object file was
874 found by the PT_INTERP name. */
875 GL(dl_rtld_map
).l_name
= (char *) GL(dl_rtld_map
).l_libname
->name
;
876 GL(dl_rtld_map
).l_type
= lt_library
;
877 GL(dl_loaded
)->l_next
= &GL(dl_rtld_map
);
878 GL(dl_rtld_map
).l_prev
= GL(dl_loaded
);
881 /* We have two ways to specify objects to preload: via environment
882 variable and via the file /etc/ld.so.preload. The latter can also
883 be used when security is enabled. */
887 if (__builtin_expect (preloadlist
!= NULL
, 0))
889 /* The LD_PRELOAD environment variable gives list of libraries
890 separated by white space or colons that are loaded before the
891 executable's dependencies and prepended to the global scope
892 list. If the binary is running setuid all elements
893 containing a '/' are ignored since it is insecure. */
894 char *list
= strdupa (preloadlist
);
897 HP_TIMING_NOW (start
);
899 /* Prevent optimizing strsep. Speed is not important here. */
900 while ((p
= (strsep
) (&list
, " :")) != NULL
)
902 && (__builtin_expect (! INTUSE(__libc_enable_secure
), 1)
903 || strchr (p
, '/') == NULL
))
905 struct link_map
*new_map
= INTUSE(_dl_map_object
) (GL(dl_loaded
),
909 if (++new_map
->l_opencount
== 1)
910 /* It is no duplicate. */
914 HP_TIMING_NOW (stop
);
915 HP_TIMING_DIFF (diff
, start
, stop
);
916 HP_TIMING_ACCUM_NT (load_time
, diff
);
919 /* Read the contents of the file. */
920 file
= _dl_sysdep_read_whole_file ("/etc/ld.so.preload", &file_size
,
921 PROT_READ
| PROT_WRITE
);
922 if (__builtin_expect (file
!= MAP_FAILED
, 0))
924 /* Parse the file. It contains names of libraries to be loaded,
925 separated by white spaces or `:'. It may also contain
926 comments introduced by `#'. */
931 /* Eliminate comments. */
936 char *comment
= memchr (runp
, '#', rest
);
940 rest
-= comment
- runp
;
943 while (--rest
> 0 && *++comment
!= '\n');
946 /* We have one problematic case: if we have a name at the end of
947 the file without a trailing terminating characters, we cannot
948 place the \0. Handle the case separately. */
949 if (file
[file_size
- 1] != ' ' && file
[file_size
- 1] != '\t'
950 && file
[file_size
- 1] != '\n' && file
[file_size
- 1] != ':')
952 problem
= &file
[file_size
];
953 while (problem
> file
&& problem
[-1] != ' ' && problem
[-1] != '\t'
954 && problem
[-1] != '\n' && problem
[-1] != ':')
963 file
[file_size
- 1] = '\0';
966 HP_TIMING_NOW (start
);
972 while ((p
= strsep (&runp
, ": \t\n")) != NULL
)
975 struct link_map
*new_map
= INTUSE(_dl_map_object
) (GL(dl_loaded
),
979 if (++new_map
->l_opencount
== 1)
980 /* It is no duplicate. */
987 char *p
= strndupa (problem
, file_size
- (problem
- file
));
988 struct link_map
*new_map
= INTUSE(_dl_map_object
) (GL(dl_loaded
), p
,
991 if (++new_map
->l_opencount
== 1)
992 /* It is no duplicate. */
996 HP_TIMING_NOW (stop
);
997 HP_TIMING_DIFF (diff
, start
, stop
);
998 HP_TIMING_ACCUM_NT (load_time
, diff
);
1000 /* We don't need the file anymore. */
1001 __munmap (file
, file_size
);
1004 if (__builtin_expect (npreloads
, 0) != 0)
1006 /* Set up PRELOADS with a vector of the preloaded libraries. */
1008 preloads
= __alloca (npreloads
* sizeof preloads
[0]);
1009 l
= GL(dl_rtld_map
).l_next
; /* End of the chain before preloads. */
1016 assert (i
== npreloads
);
1019 /* Load all the libraries specified by DT_NEEDED entries. If LD_PRELOAD
1020 specified some libraries to load, these are inserted before the actual
1021 dependencies in the executable's searchlist for symbol resolution. */
1022 HP_TIMING_NOW (start
);
1023 INTUSE(_dl_map_object_deps
) (GL(dl_loaded
), preloads
, npreloads
,
1025 HP_TIMING_NOW (stop
);
1026 HP_TIMING_DIFF (diff
, start
, stop
);
1027 HP_TIMING_ACCUM_NT (load_time
, diff
);
1029 /* Mark all objects as being in the global scope and set the open
1031 for (i
= GL(dl_loaded
)->l_searchlist
.r_nlist
; i
> 0; )
1034 GL(dl_loaded
)->l_searchlist
.r_list
[i
]->l_global
= 1;
1035 ++GL(dl_loaded
)->l_searchlist
.r_list
[i
]->l_opencount
;
1039 /* We are done mapping things, so close the zero-fill descriptor. */
1040 __close (_dl_zerofd
);
1044 /* Remove _dl_rtld_map from the chain. */
1045 GL(dl_rtld_map
).l_prev
->l_next
= GL(dl_rtld_map
).l_next
;
1046 if (GL(dl_rtld_map
).l_next
)
1047 GL(dl_rtld_map
).l_next
->l_prev
= GL(dl_rtld_map
).l_prev
;
1049 if (__builtin_expect (GL(dl_rtld_map
).l_opencount
> 1, 1))
1051 /* Some DT_NEEDED entry referred to the interpreter object itself, so
1052 put it back in the list of visible objects. We insert it into the
1053 chain in symbol search order because gdb uses the chain's order as
1054 its symbol search order. */
1056 while (GL(dl_loaded
)->l_searchlist
.r_list
[i
] != &GL(dl_rtld_map
))
1058 GL(dl_rtld_map
).l_prev
= GL(dl_loaded
)->l_searchlist
.r_list
[i
- 1];
1059 if (__builtin_expect (mode
, normal
) == normal
)
1060 GL(dl_rtld_map
).l_next
= (i
+ 1 < GL(dl_loaded
)->l_searchlist
.r_nlist
1061 ? GL(dl_loaded
)->l_searchlist
.r_list
[i
+ 1]
1064 /* In trace mode there might be an invisible object (which we
1065 could not find) after the previous one in the search list.
1066 In this case it doesn't matter much where we put the
1067 interpreter object, so we just initialize the list pointer so
1068 that the assertion below holds. */
1069 GL(dl_rtld_map
).l_next
= GL(dl_rtld_map
).l_prev
->l_next
;
1071 assert (GL(dl_rtld_map
).l_prev
->l_next
== GL(dl_rtld_map
).l_next
);
1072 GL(dl_rtld_map
).l_prev
->l_next
= &GL(dl_rtld_map
);
1073 if (GL(dl_rtld_map
).l_next
!= NULL
)
1075 assert (GL(dl_rtld_map
).l_next
->l_prev
== GL(dl_rtld_map
).l_prev
);
1076 GL(dl_rtld_map
).l_next
->l_prev
= &GL(dl_rtld_map
);
1080 /* Now let us see whether all libraries are available in the
1081 versions we need. */
1083 struct version_check_args args
;
1084 args
.doexit
= mode
== normal
;
1085 args
.dotrace
= mode
== trace
;
1086 _dl_receive_error (print_missing_version
, version_check_doit
, &args
);
1090 /* Now it is time to determine the layout of the static TLS block
1091 and allocate it for the initial thread. Note that we always
1092 allocate the static block, we never defer it even if no
1093 DF_STATIC_TLS bit is set. The reason is that we know glibc will
1094 use the static model. First add the dynamic linker to the list
1095 if it also uses TLS. */
1096 if (GL(dl_rtld_map
).l_tls_blocksize
!= 0)
1097 /* Assign a module ID. */
1098 GL(dl_rtld_map
).l_tls_modid
= _dl_next_tls_modid ();
1101 /* If dynamic loading of modules with TLS is impossible we do not
1102 have to initialize any of the TLS functionality unless any of the
1103 initial modules uses TLS. */
1104 if (GL(dl_tls_max_dtv_idx
) > 0)
1109 struct dtv_slotinfo
*slotinfo
;
1111 /* Number of elements in the static TLS block. */
1112 GL(dl_tls_static_nelem
) = GL(dl_tls_max_dtv_idx
);
1114 /* Allocate the array which contains the information about the
1115 dtv slots. We allocate a few entries more than needed to
1116 avoid the need for reallocation. */
1117 nelem
= GL(dl_tls_max_dtv_idx
) + 1 + TLS_SLOTINFO_SURPLUS
;
1120 GL(dl_tls_dtv_slotinfo_list
) = (struct dtv_slotinfo_list
*)
1121 malloc (sizeof (struct dtv_slotinfo_list
)
1122 + nelem
* sizeof (struct dtv_slotinfo
));
1123 /* No need to check the return value. If memory allocation failed
1124 the program would have been terminated. */
1126 slotinfo
= memset (GL(dl_tls_dtv_slotinfo_list
)->slotinfo
, '\0',
1127 nelem
* sizeof (struct dtv_slotinfo
));
1128 GL(dl_tls_dtv_slotinfo_list
)->len
= nelem
;
1129 GL(dl_tls_dtv_slotinfo_list
)->next
= NULL
;
1131 /* Fill in the information from the loaded modules. */
1132 for (l
= GL(dl_loaded
), i
= 0; l
!= NULL
; l
= l
->l_next
)
1133 if (l
->l_tls_blocksize
!= 0)
1134 /* This is a module with TLS data. Store the map reference.
1135 The generation counter is zero. */
1136 slotinfo
[++i
].map
= l
;
1137 assert (i
== GL(dl_tls_max_dtv_idx
));
1139 /* Compute the TLS offsets for the various blocks. We call this
1140 function even if none of the modules available at startup time
1141 uses TLS to initialize some variables. */
1142 _dl_determine_tlsoffset ();
1144 /* Construct the static TLS block and the dtv for the initial
1145 thread. For some platforms this will include allocating memory
1146 for the thread descriptor. The memory for the TLS block will
1147 never be freed. It should be allocated accordingly. The dtv
1148 array can be changed if dynamic loading requires it. */
1149 tcbp
= _dl_allocate_tls_storage ();
1151 _dl_fatal_printf ("\
1152 cannot allocate TLS data structures for initial thread");
1154 /* Store for detection of the special case by __tls_get_addr
1155 so it knows not to pass this dtv to the normal realloc. */
1156 GL(dl_initial_dtv
) = GET_DTV (tcbp
);
1160 if (__builtin_expect (mode
, normal
) != normal
)
1162 /* We were run just to list the shared libraries. It is
1163 important that we do this before real relocation, because the
1164 functions we call below for output may no longer work properly
1165 after relocation. */
1166 if (! GL(dl_loaded
)->l_info
[DT_NEEDED
])
1167 _dl_printf ("\tstatically linked\n");
1172 if (GL(dl_debug_mask
) & DL_DEBUG_PRELINK
)
1174 struct r_scope_elem
*scope
= &GL(dl_loaded
)->l_searchlist
;
1176 for (i
= 0; i
< scope
->r_nlist
; i
++)
1178 l
= scope
->r_list
[i
];
1181 _dl_printf ("\t%s => not found\n", l
->l_libname
->name
);
1184 if (_dl_name_match_p (GL(dl_trace_prelink
), l
))
1185 GL(dl_trace_prelink_map
) = l
;
1186 _dl_printf ("\t%s => %s (0x%0*Zx, 0x%0*Zx)",
1187 l
->l_libname
->name
[0] ? l
->l_libname
->name
1188 : rtld_progname
?: "<main program>",
1189 l
->l_name
[0] ? l
->l_name
1190 : rtld_progname
?: "<main program>",
1191 (int) sizeof l
->l_map_start
* 2,
1193 (int) sizeof l
->l_addr
* 2,
1197 _dl_printf (" TLS(0x%Zx, 0x%0*Zx)\n", l
->l_tls_modid
,
1198 (int) sizeof l
->l_tls_offset
* 2,
1207 for (l
= GL(dl_loaded
)->l_next
; l
; l
= l
->l_next
)
1209 /* The library was not found. */
1210 _dl_printf ("\t%s => not found\n", l
->l_libname
->name
);
1212 _dl_printf ("\t%s => %s (0x%0*Zx)\n", l
->l_libname
->name
,
1213 l
->l_name
, (int) sizeof l
->l_map_start
* 2,
1218 if (__builtin_expect (mode
, trace
) != trace
)
1219 for (i
= 1; i
< (unsigned int) _dl_argc
; ++i
)
1221 const ElfW(Sym
) *ref
= NULL
;
1222 ElfW(Addr
) loadbase
;
1225 result
= INTUSE(_dl_lookup_symbol
) (INTUSE(_dl_argv
)[i
],
1227 &ref
, GL(dl_loaded
)->l_scope
,
1228 ELF_RTYPE_CLASS_PLT
, 1);
1230 loadbase
= LOOKUP_VALUE_ADDRESS (result
);
1232 _dl_printf ("%s found at 0x%0*Zd in object at 0x%0*Zd\n",
1233 INTUSE(_dl_argv
)[i
],
1234 (int) sizeof ref
->st_value
* 2, ref
->st_value
,
1235 (int) sizeof loadbase
* 2, loadbase
);
1239 /* If LD_WARN is set warn about undefined symbols. */
1240 if (GL(dl_lazy
) >= 0 && GL(dl_verbose
))
1242 /* We have to do symbol dependency testing. */
1243 struct relocate_args args
;
1246 args
.lazy
= GL(dl_lazy
);
1253 if (l
!= &GL(dl_rtld_map
) && ! l
->l_faked
)
1256 _dl_receive_error (print_unresolved
, relocate_doit
,
1262 if ((GL(dl_debug_mask
) & DL_DEBUG_PRELINK
)
1263 && GL(dl_rtld_map
).l_opencount
> 1)
1264 INTUSE(_dl_relocate_object
) (&GL(dl_rtld_map
),
1265 GL(dl_loaded
)->l_scope
, 0, 0);
1268 #define VERNEEDTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERNEED))
1271 /* Print more information. This means here, print information
1272 about the versions needed. */
1274 struct link_map
*map
= GL(dl_loaded
);
1276 for (map
= GL(dl_loaded
); map
!= NULL
; map
= map
->l_next
)
1279 ElfW(Dyn
) *dyn
= map
->l_info
[VERNEEDTAG
];
1285 strtab
= (const void *) D_PTR (map
, l_info
[DT_STRTAB
]);
1286 ent
= (ElfW(Verneed
) *) (map
->l_addr
+ dyn
->d_un
.d_ptr
);
1290 _dl_printf ("\n\tVersion information:\n");
1294 _dl_printf ("\t%s:\n",
1295 map
->l_name
[0] ? map
->l_name
: rtld_progname
);
1300 struct link_map
*needed
;
1302 needed
= find_needed (strtab
+ ent
->vn_file
);
1303 aux
= (ElfW(Vernaux
) *) ((char *) ent
+ ent
->vn_aux
);
1307 const char *fname
= NULL
;
1310 && match_version (strtab
+ aux
->vna_name
,
1312 fname
= needed
->l_name
;
1314 _dl_printf ("\t\t%s (%s) %s=> %s\n",
1315 strtab
+ ent
->vn_file
,
1316 strtab
+ aux
->vna_name
,
1317 aux
->vna_flags
& VER_FLG_WEAK
1319 fname
?: "not found");
1321 if (aux
->vna_next
== 0)
1322 /* No more symbols. */
1326 aux
= (ElfW(Vernaux
) *) ((char *) aux
1330 if (ent
->vn_next
== 0)
1331 /* No more dependencies. */
1334 /* Next dependency. */
1335 ent
= (ElfW(Verneed
) *) ((char *) ent
+ ent
->vn_next
);
1344 if (GL(dl_loaded
)->l_info
[ADDRIDX (DT_GNU_LIBLIST
)]
1345 && ! __builtin_expect (GL(dl_profile
) != NULL
, 0))
1347 ElfW(Lib
) *liblist
, *liblistend
;
1348 struct link_map
**r_list
, **r_listend
, *l
;
1349 const char *strtab
= (const void *) D_PTR (GL(dl_loaded
),
1352 assert (GL(dl_loaded
)->l_info
[VALIDX (DT_GNU_LIBLISTSZ
)] != NULL
);
1353 liblist
= (ElfW(Lib
) *)
1354 GL(dl_loaded
)->l_info
[ADDRIDX (DT_GNU_LIBLIST
)]->d_un
.d_ptr
;
1355 liblistend
= (ElfW(Lib
) *)
1357 + GL(dl_loaded
)->l_info
[VALIDX (DT_GNU_LIBLISTSZ
)]->d_un
.d_val
);
1358 r_list
= GL(dl_loaded
)->l_searchlist
.r_list
;
1359 r_listend
= r_list
+ GL(dl_loaded
)->l_searchlist
.r_nlist
;
1361 for (; r_list
< r_listend
&& liblist
< liblistend
; r_list
++)
1365 if (l
== GL(dl_loaded
))
1368 /* If the library is not mapped where it should, fail. */
1372 /* Next, check if checksum matches. */
1373 if (l
->l_info
[VALIDX(DT_CHECKSUM
)] == NULL
1374 || l
->l_info
[VALIDX(DT_CHECKSUM
)]->d_un
.d_val
1375 != liblist
->l_checksum
)
1378 if (l
->l_info
[VALIDX(DT_GNU_PRELINKED
)] == NULL
1379 || l
->l_info
[VALIDX(DT_GNU_PRELINKED
)]->d_un
.d_val
1380 != liblist
->l_time_stamp
)
1383 if (! _dl_name_match_p (strtab
+ liblist
->l_name
, l
))
1390 if (r_list
== r_listend
&& liblist
== liblistend
)
1393 if (__builtin_expect (GL(dl_debug_mask
) & DL_DEBUG_LIBS
, 0))
1394 _dl_printf ("\nprelink checking: %s\n", prelinked
? "ok" : "failed");
1399 if (GL(dl_loaded
)->l_info
[ADDRIDX (DT_GNU_CONFLICT
)] != NULL
)
1401 ElfW(Rela
) *conflict
, *conflictend
;
1402 #ifndef HP_TIMING_NONAVAIL
1407 HP_TIMING_NOW (start
);
1408 assert (GL(dl_loaded
)->l_info
[VALIDX (DT_GNU_CONFLICTSZ
)] != NULL
);
1409 conflict
= (ElfW(Rela
) *)
1410 GL(dl_loaded
)->l_info
[ADDRIDX (DT_GNU_CONFLICT
)]->d_un
.d_ptr
;
1411 conflictend
= (ElfW(Rela
) *)
1413 + GL(dl_loaded
)->l_info
[VALIDX (DT_GNU_CONFLICTSZ
)]->d_un
.d_val
);
1414 _dl_resolve_conflicts (GL(dl_loaded
), conflict
, conflictend
);
1415 HP_TIMING_NOW (stop
);
1416 HP_TIMING_DIFF (relocate_time
, start
, stop
);
1419 _dl_sysdep_start_cleanup ();
1423 /* Now we have all the objects loaded. Relocate them all except for
1424 the dynamic linker itself. We do this in reverse order so that copy
1425 relocs of earlier objects overwrite the data written by later
1426 objects. We do not re-relocate the dynamic linker itself in this
1427 loop because that could result in the GOT entries for functions we
1428 call being changed, and that would break us. It is safe to relocate
1429 the dynamic linker out of order because it has no copy relocs (we
1430 know that because it is self-contained). */
1433 int consider_profiling
= GL(dl_profile
) != NULL
;
1434 #ifndef HP_TIMING_NONAVAIL
1440 /* If we are profiling we also must do lazy reloaction. */
1441 GL(dl_lazy
) |= consider_profiling
;
1447 HP_TIMING_NOW (start
);
1450 /* While we are at it, help the memory handling a bit. We have to
1451 mark some data structures as allocated with the fake malloc()
1452 implementation in ld.so. */
1453 struct libname_list
*lnp
= l
->l_libname
->next
;
1455 while (__builtin_expect (lnp
!= NULL
, 0))
1461 if (l
!= &GL(dl_rtld_map
))
1462 INTUSE(_dl_relocate_object
) (l
, l
->l_scope
, GL(dl_lazy
),
1463 consider_profiling
);
1468 HP_TIMING_NOW (stop
);
1470 HP_TIMING_DIFF (relocate_time
, start
, stop
);
1472 /* Do any necessary cleanups for the startup OS interface code.
1473 We do these now so that no calls are made after rtld re-relocation
1474 which might be resolved to different functions than we expect.
1475 We cannot do this before relocating the other objects because
1476 _dl_relocate_object might need to call `mprotect' for DT_TEXTREL. */
1477 _dl_sysdep_start_cleanup ();
1479 /* Now enable profiling if needed. Like the previous call,
1480 this has to go here because the calls it makes should use the
1481 rtld versions of the functions (particularly calloc()), but it
1482 needs to have _dl_profile_map set up by the relocator. */
1483 if (__builtin_expect (GL(dl_profile_map
) != NULL
, 0))
1484 /* We must prepare the profiling. */
1485 INTUSE(_dl_start_profile
) (GL(dl_profile_map
), GL(dl_profile_output
));
1487 if (GL(dl_rtld_map
).l_opencount
> 1)
1489 /* There was an explicit ref to the dynamic linker as a shared lib.
1490 Re-relocate ourselves with user-controlled symbol definitions. */
1491 HP_TIMING_NOW (start
);
1492 INTUSE(_dl_relocate_object
) (&GL(dl_rtld_map
), GL(dl_loaded
)->l_scope
,
1494 HP_TIMING_NOW (stop
);
1495 HP_TIMING_DIFF (add
, start
, stop
);
1496 HP_TIMING_ACCUM_NT (relocate_time
, add
);
1500 /* Now set up the variable which helps the assembler startup code. */
1501 GL(dl_main_searchlist
) = &GL(dl_loaded
)->l_searchlist
;
1502 GL(dl_global_scope
)[0] = &GL(dl_loaded
)->l_searchlist
;
1504 /* Save the information about the original global scope list since
1505 we need it in the memory handling later. */
1506 GL(dl_initial_searchlist
) = *GL(dl_main_searchlist
);
1510 if (GL(dl_tls_max_dtv_idx
) > 0)
1513 /* Now that we have completed relocation, the initializer data
1514 for the TLS blocks has its final values and we can copy them
1515 into the main thread's TLS area, which we allocated above. */
1516 _dl_allocate_tls_init (tcbp
);
1518 /* And finally install it for the main thread. */
1519 # ifndef HAVE___THREAD
1520 TLS_INIT_TP (tcbp
, GL(dl_rtld_map
).l_tls_tp_initialized
);
1522 /* If the compiler supports the __thread keyword we know that
1523 at least ld.so itself uses TLS and therefore the thread
1524 pointer was initialized earlier. */
1525 assert (GL(dl_rtld_map
).l_tls_tp_initialized
!= 0);
1526 TLS_INIT_TP (tcbp
, 1);
1532 /* Initialize _r_debug. */
1533 struct r_debug
*r
= _dl_debug_initialize (GL(dl_rtld_map
).l_addr
);
1538 #ifdef ELF_MACHINE_DEBUG_SETUP
1540 /* Some machines (e.g. MIPS) don't use DT_DEBUG in this way. */
1542 ELF_MACHINE_DEBUG_SETUP (l
, r
);
1543 ELF_MACHINE_DEBUG_SETUP (&GL(dl_rtld_map
), r
);
1547 if (l
->l_info
[DT_DEBUG
] != NULL
)
1548 /* There is a DT_DEBUG entry in the dynamic section. Fill it in
1549 with the run-time address of the r_debug structure */
1550 l
->l_info
[DT_DEBUG
]->d_un
.d_ptr
= (ElfW(Addr
)) r
;
1552 /* Fill in the pointer in the dynamic linker's own dynamic section, in
1553 case you run gdb on the dynamic linker directly. */
1554 if (GL(dl_rtld_map
).l_info
[DT_DEBUG
] != NULL
)
1555 GL(dl_rtld_map
).l_info
[DT_DEBUG
]->d_un
.d_ptr
= (ElfW(Addr
)) r
;
1559 /* Notify the debugger that all objects are now mapped in. */
1560 r
->r_state
= RT_ADD
;
1561 INTUSE(_dl_debug_state
) ();
1565 /* We must munmap() the cache file. */
1566 INTUSE(_dl_unload_cache
) ();
1569 /* Once we return, _dl_sysdep_start will invoke
1570 the DT_INIT functions and then *USER_ENTRY. */
1573 /* This is a little helper function for resolving symbols while
1574 tracing the binary. */
1576 print_unresolved (int errcode
__attribute__ ((unused
)), const char *objname
,
1577 const char *errstring
)
1579 if (objname
[0] == '\0')
1580 objname
= rtld_progname
?: "<main program>";
1581 _dl_error_printf ("%s (%s)\n", errstring
, objname
);
1584 /* This is a little helper function for resolving symbols while
1585 tracing the binary. */
1587 print_missing_version (int errcode
__attribute__ ((unused
)),
1588 const char *objname
, const char *errstring
)
1590 _dl_error_printf ("%s: %s: %s\n", rtld_progname
?: "<program name unknown>",
1591 objname
, errstring
);
1594 /* Nonzero if any of the debugging options is enabled. */
1595 static int any_debug
;
1597 /* Process the string given as the parameter which explains which debugging
1598 options are enabled. */
1600 process_dl_debug (const char *dl_debug
)
1602 /* When adding new entries make sure that the maximal length of a name
1603 is correctly handled in the LD_DEBUG_HELP code below. */
1607 const char name
[10];
1608 const char helptext
[41];
1609 unsigned short int mask
;
1612 #define LEN_AND_STR(str) sizeof (str) - 1, str
1613 { LEN_AND_STR ("libs"), "display library search paths",
1614 DL_DEBUG_LIBS
| DL_DEBUG_IMPCALLS
},
1615 { LEN_AND_STR ("reloc"), "display relocation processing",
1616 DL_DEBUG_RELOC
| DL_DEBUG_IMPCALLS
},
1617 { LEN_AND_STR ("files"), "display progress for input file",
1618 DL_DEBUG_FILES
| DL_DEBUG_IMPCALLS
},
1619 { LEN_AND_STR ("symbols"), "display symbol table processing",
1620 DL_DEBUG_SYMBOLS
| DL_DEBUG_IMPCALLS
},
1621 { LEN_AND_STR ("bindings"), "display information about symbol binding",
1622 DL_DEBUG_BINDINGS
| DL_DEBUG_IMPCALLS
},
1623 { LEN_AND_STR ("versions"), "display version dependencies",
1624 DL_DEBUG_VERSIONS
| DL_DEBUG_IMPCALLS
},
1625 { LEN_AND_STR ("all"), "all previous options combined",
1626 DL_DEBUG_LIBS
| DL_DEBUG_RELOC
| DL_DEBUG_FILES
| DL_DEBUG_SYMBOLS
1627 | DL_DEBUG_BINDINGS
| DL_DEBUG_VERSIONS
| DL_DEBUG_IMPCALLS
},
1628 { LEN_AND_STR ("statistics"), "display relocation statistics",
1629 DL_DEBUG_STATISTICS
},
1630 { LEN_AND_STR ("help"), "display this help message and exit",
1633 #define ndebopts (sizeof (debopts) / sizeof (debopts[0]))
1635 /* Skip separating white spaces and commas. */
1636 while (*dl_debug
!= '\0')
1638 if (*dl_debug
!= ' ' && *dl_debug
!= ',' && *dl_debug
!= ':')
1643 while (dl_debug
[len
] != '\0' && dl_debug
[len
] != ' '
1644 && dl_debug
[len
] != ',' && dl_debug
[len
] != ':')
1647 for (cnt
= 0; cnt
< ndebopts
; ++cnt
)
1648 if (debopts
[cnt
].len
== len
1649 && memcmp (dl_debug
, debopts
[cnt
].name
, len
) == 0)
1651 GL(dl_debug_mask
) |= debopts
[cnt
].mask
;
1656 if (cnt
== ndebopts
)
1658 /* Display a warning and skip everything until next
1660 char *copy
= strndupa (dl_debug
, len
);
1661 _dl_error_printf ("\
1662 warning: debug option `%s' unknown; try LD_DEBUG=help\n", copy
);
1672 if (GL(dl_debug_mask
) & DL_DEBUG_HELP
)
1677 Valid options for the LD_DEBUG environment variable are:\n\n");
1679 for (cnt
= 0; cnt
< ndebopts
; ++cnt
)
1680 _dl_printf (" %.*s%s%s\n", debopts
[cnt
].len
, debopts
[cnt
].name
,
1681 " " + debopts
[cnt
].len
- 3,
1682 debopts
[cnt
].helptext
);
1685 To direct the debugging output into a file instead of standard output\n\
1686 a filename can be specified using the LD_DEBUG_OUTPUT environment variable.\n");
1691 /* Process all environments variables the dynamic linker must recognize.
1692 Since all of them start with `LD_' we are a bit smarter while finding
1694 extern char **_environ attribute_hidden
;
1698 process_envvars (enum mode
*modep
)
1700 char **runp
= _environ
;
1702 enum mode mode
= normal
;
1703 char *debug_output
= NULL
;
1705 /* This is the default place for profiling data file. */
1706 GL(dl_profile_output
)
1707 = &"/var/tmp\0/var/profile"[INTUSE(__libc_enable_secure
) ? 9 : 0];
1709 while ((envline
= _dl_next_ld_env_entry (&runp
)) != NULL
)
1713 while (envline
[len
] != '\0' && envline
[len
] != '=')
1716 if (envline
[len
] != '=')
1717 /* This is a "LD_" variable at the end of the string without
1718 a '=' character. Ignore it since otherwise we will access
1719 invalid memory below. */
1725 /* Warning level, verbose or not. */
1726 if (memcmp (envline
, "WARN", 4) == 0)
1727 GL(dl_verbose
) = envline
[5] != '\0';
1731 /* Debugging of the dynamic linker? */
1732 if (memcmp (envline
, "DEBUG", 5) == 0)
1733 process_dl_debug (&envline
[6]);
1737 /* Print information about versions. */
1738 if (memcmp (envline
, "VERBOSE", 7) == 0)
1740 version_info
= envline
[8] != '\0';
1744 /* List of objects to be preloaded. */
1745 if (memcmp (envline
, "PRELOAD", 7) == 0)
1747 preloadlist
= &envline
[8];
1751 /* Which shared object shall be profiled. */
1752 if (memcmp (envline
, "PROFILE", 7) == 0 && envline
[8] != '\0')
1753 GL(dl_profile
) = &envline
[8];
1757 /* Do we bind early? */
1758 if (memcmp (envline
, "BIND_NOW", 8) == 0)
1760 GL(dl_lazy
) = envline
[9] == '\0';
1763 if (memcmp (envline
, "BIND_NOT", 8) == 0)
1764 GL(dl_bind_not
) = envline
[9] != '\0';
1768 /* Test whether we want to see the content of the auxiliary
1769 array passed up from the kernel. */
1770 if (memcmp (envline
, "SHOW_AUXV", 9) == 0)
1775 /* Mask for the important hardware capabilities. */
1776 if (memcmp (envline
, "HWCAP_MASK", 10) == 0)
1777 GL(dl_hwcap_mask
) = __strtoul_internal (&envline
[11], NULL
, 0, 0);
1781 /* Path where the binary is found. */
1782 if (!INTUSE(__libc_enable_secure
)
1783 && memcmp (envline
, "ORIGIN_PATH", 11) == 0)
1784 GL(dl_origin_path
) = &envline
[12];
1788 /* The library search path. */
1789 if (memcmp (envline
, "LIBRARY_PATH", 12) == 0)
1791 library_path
= &envline
[13];
1795 /* Where to place the profiling data file. */
1796 if (memcmp (envline
, "DEBUG_OUTPUT", 12) == 0)
1798 debug_output
= &envline
[13];
1802 if (memcmp (envline
, "DYNAMIC_WEAK", 12) == 0)
1803 GL(dl_dynamic_weak
) = 1;
1807 /* Where to place the profiling data file. */
1808 if (!INTUSE(__libc_enable_secure
)
1809 && memcmp (envline
, "PROFILE_OUTPUT", 14) == 0
1810 && envline
[15] != '\0')
1811 GL(dl_profile_output
) = &envline
[15];
1815 /* The mode of the dynamic linker can be set. */
1816 if (memcmp (envline
, "TRACE_PRELINKING", 16) == 0)
1820 GL(dl_debug_mask
) |= DL_DEBUG_PRELINK
;
1821 GL(dl_trace_prelink
) = &envline
[17];
1826 /* The mode of the dynamic linker can be set. */
1827 if (memcmp (envline
, "TRACE_LOADED_OBJECTS", 20) == 0)
1831 /* We might have some extra environment variable to handle. This
1832 is tricky due to the pre-processing of the length of the name
1833 in the switch statement here. The code here assumes that added
1834 environment variables have a different length. */
1835 #ifdef EXTRA_LD_ENVVARS
1841 /* The caller wants this information. */
1844 /* Extra security for SUID binaries. Remove all dangerous environment
1846 if (__builtin_expect (INTUSE(__libc_enable_secure
), 0))
1848 static const char unsecure_envvars
[] =
1849 #ifdef EXTRA_UNSECURE_ENVVARS
1850 EXTRA_UNSECURE_ENVVARS
1855 nextp
= unsecure_envvars
;
1859 /* We could use rawmemchr but this need not be fast. */
1860 nextp
= (char *) (strchr
) (nextp
, '\0') + 1;
1862 while (*nextp
!= '\0');
1864 if (__access ("/etc/suid-debug", F_OK
) != 0)
1865 unsetenv ("MALLOC_CHECK_");
1867 /* If we have to run the dynamic linker in debugging mode and the
1868 LD_DEBUG_OUTPUT environment variable is given, we write the debug
1869 messages to this file. */
1870 else if (any_debug
&& debug_output
!= NULL
)
1873 const int flags
= O_WRONLY
| O_APPEND
| O_CREAT
| O_NOFOLLOW
;
1875 const int flags
= O_WRONLY
| O_APPEND
| O_CREAT
;
1877 size_t name_len
= strlen (debug_output
);
1878 char buf
[name_len
+ 12];
1881 buf
[name_len
+ 11] = '\0';
1882 startp
= _itoa (__getpid (), &buf
[name_len
+ 11], 10, 0);
1884 startp
= memcpy (startp
- name_len
, debug_output
, name_len
);
1886 GL(dl_debug_fd
) = __open (startp
, flags
, DEFFILEMODE
);
1887 if (GL(dl_debug_fd
) == -1)
1888 /* We use standard output if opening the file failed. */
1889 GL(dl_debug_fd
) = STDOUT_FILENO
;
1894 /* Print the various times we collected. */
1896 print_statistics (void)
1898 #ifndef HP_TIMING_NONAVAIL
1903 /* Total time rtld used. */
1904 if (HP_TIMING_AVAIL
)
1906 HP_TIMING_PRINT (buf
, sizeof (buf
), rtld_total_time
);
1907 INTUSE(_dl_debug_printf
) ("\nruntime linker statistics:\n"
1908 " total startup time in dynamic loader: %s\n",
1912 /* Print relocation statistics. */
1913 if (HP_TIMING_AVAIL
)
1916 HP_TIMING_PRINT (buf
, sizeof (buf
), relocate_time
);
1917 cp
= _itoa ((1000ULL * relocate_time
) / rtld_total_time
,
1918 pbuf
+ sizeof (pbuf
), 10, 0);
1920 switch (pbuf
+ sizeof (pbuf
) - cp
)
1931 INTUSE(_dl_debug_printf
) ("\
1932 time needed for relocation: %s (%s%%)\n",
1936 INTUSE(_dl_debug_printf
) (" number of relocations: %lu\n",
1937 GL(dl_num_relocations
));
1938 INTUSE(_dl_debug_printf
) (" number of relocations from cache: %lu\n",
1939 GL(dl_num_cache_relocations
));
1941 #ifndef HP_TIMING_NONAVAIL
1942 /* Time spend while loading the object and the dependencies. */
1943 if (HP_TIMING_AVAIL
)
1946 HP_TIMING_PRINT (buf
, sizeof (buf
), load_time
);
1947 cp
= _itoa ((1000ULL * load_time
) / rtld_total_time
,
1948 pbuf
+ sizeof (pbuf
), 10, 0);
1950 switch (pbuf
+ sizeof (pbuf
) - cp
)
1961 INTUSE(_dl_debug_printf
) ("\
1962 time needed to load objects: %s (%s%%)\n",