1 /* Run time dynamic linker.
2 Copyright (C) 1995-1999, 2000, 2001 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 Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 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 Library General Public License for more details.
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If not,
17 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA. */
24 #include <sys/mman.h> /* Check if MAP_ANON is defined. */
27 #include <stdio-common/_itoa.h>
29 #include <fpu_control.h>
30 #include <hp-timing.h>
31 #include <bits/libc-lock.h>
32 #include "dynamic-link.h"
33 #include "dl-librecon.h"
34 #include <unsecvars.h>
38 /* Helper function to handle errors while resolving symbols. */
39 static void print_unresolved (int errcode
, const char *objname
,
40 const char *errsting
);
42 /* Helper function to handle errors when a version is missing. */
43 static void print_missing_version (int errcode
, const char *objname
,
44 const char *errsting
);
46 /* Print the various times we collected. */
47 static void print_statistics (void);
49 /* This is a list of all the modes the dynamic loader can be in. */
50 enum mode
{ normal
, list
, verify
, trace
};
52 /* Process all environments variables the dynamic linker must recognize.
53 Since all of them start with `LD_' we are a bit smarter while finding
55 static void process_envvars (enum mode
*modep
);
59 unsigned int _dl_skip_args
; /* Nonzero if we were run directly. */
61 const char *_dl_platform
;
62 size_t _dl_platformlen
;
63 unsigned long _dl_hwcap
;
64 fpu_control_t _dl_fpu_control
= _FPU_DEFAULT
;
65 struct r_search_path
*_dl_search_paths
;
66 const char *_dl_profile
;
67 const char *_dl_profile_output
;
68 struct link_map
*_dl_profile_map
;
70 /* XXX I know about at least one case where we depend on the old weak
71 behavior (it has to do with librt). Until we get DSO groups implemented
72 we have to make this the default. Bummer. --drepper */
76 int _dl_dynamic_weak
= 1;
79 const char *_dl_inhibit_rpath
; /* RPATH values which should be
81 const char *_dl_origin_path
;
84 /* This is a pointer to the map for the main object and through it to
85 all loaded objects. */
86 struct link_map
*_dl_loaded
;
87 /* Number of object in the _dl_loaded list. */
88 unsigned int _dl_nloaded
;
89 /* Pointer to the l_searchlist element of the link map of the main object. */
90 struct r_scope_elem
*_dl_main_searchlist
;
91 /* Copy of the content of `_dl_main_searchlist'. */
92 struct r_scope_elem _dl_initial_searchlist
;
93 /* Array which is used when looking up in the global scope. */
94 struct r_scope_elem
*_dl_global_scope
[2];
96 /* During the program run we must not modify the global data of
97 loaded shared object simultanously in two threads. Therefore we
98 protect `_dl_open' and `_dl_close' in dl-close.c.
100 This must be a recursive lock since the initializer function of
101 the loaded object might as well require a call to this function.
102 At this time it is not anymore a problem to modify the tables. */
103 __libc_lock_define_initialized_recursive (, _dl_load_lock
)
105 /* Set nonzero during loading and initialization of executable and
106 libraries, cleared before the executable's entry point runs. This
107 must not be initialized to nonzero, because the unused dynamic
108 linker loaded in for libc.so's "ld.so.1" dep will provide the
109 definition seen by libc.so's initializer; that value must be zero,
110 and will be since that dynamic linker's _dl_start and dl_main will
115 static void dl_main (const ElfW(Phdr
) *phdr
,
117 ElfW(Addr
) *user_entry
);
119 struct link_map _dl_rtld_map
;
120 struct libname_list _dl_rtld_libname
;
121 struct libname_list _dl_rtld_libname2
;
123 /* Variable for statistics. */
124 #ifndef HP_TIMING_NONAVAIL
125 static hp_timing_t rtld_total_time
;
126 static hp_timing_t relocate_time
;
127 static hp_timing_t load_time
;
129 extern unsigned long int _dl_num_relocations
; /* in dl-lookup.c */
131 static ElfW(Addr
) _dl_start_final (void *arg
, struct link_map
*bootstrap_map_p
,
132 hp_timing_t start_time
);
137 #error "sysdeps/MACHINE/dl-machine.h fails to define RTLD_START"
141 _dl_start (void *arg
)
143 struct link_map bootstrap_map
;
144 hp_timing_t start_time
;
147 /* This #define produces dynamic linking inline functions for
148 bootstrap relocation instead of general-purpose relocation. */
149 #define RTLD_BOOTSTRAP
150 #define RESOLVE_MAP(sym, version, flags) \
151 ((*(sym))->st_shndx == SHN_UNDEF ? 0 : &bootstrap_map)
152 #define RESOLVE(sym, version, flags) \
153 ((*(sym))->st_shndx == SHN_UNDEF ? 0 : bootstrap_map.l_addr)
154 #include "dynamic-link.h"
156 if (HP_TIMING_INLINE
&& HP_TIMING_AVAIL
)
157 HP_TIMING_NOW (start_time
);
159 /* Partly clean the `bootstrap_map' structure up. Don't use `memset'
160 since it might nor be built in or inlined and we cannot make function
161 calls at this point. */
163 cnt
< sizeof (bootstrap_map
.l_info
) / sizeof (bootstrap_map
.l_info
[0]);
165 bootstrap_map
.l_info
[cnt
] = 0;
167 /* Figure out the run-time load address of the dynamic linker itself. */
168 bootstrap_map
.l_addr
= elf_machine_load_address ();
170 /* Read our own dynamic section and fill in the info array. */
171 bootstrap_map
.l_ld
= (void *) bootstrap_map
.l_addr
+ elf_machine_dynamic ();
172 elf_get_dynamic_info (&bootstrap_map
);
174 #ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
175 ELF_MACHINE_BEFORE_RTLD_RELOC (bootstrap_map
.l_info
);
178 /* Relocate ourselves so we can do normal function calls and
179 data access using the global offset table. */
181 ELF_DYNAMIC_RELOCATE (&bootstrap_map
, 0, 0);
182 /* Please note that we don't allow profiling of this object and
183 therefore need not test whether we have to allocate the array
184 for the relocation results (as done in dl-reloc.c). */
186 /* Now life is sane; we can call functions and access global data.
187 Set up to use the operating system facilities, and find out from
188 the operating system's program loader where to find the program
189 header table in core. Put the rest of _dl_start into a separate
190 function, that way the compiler cannot put accesses to the GOT
191 before ELF_DYNAMIC_RELOCATE. */
193 ElfW(Addr
) entry
= _dl_start_final (arg
, &bootstrap_map
, start_time
);
195 #ifndef ELF_MACHINE_START_ADDRESS
196 # define ELF_MACHINE_START_ADDRESS(map, start) (start)
199 return ELF_MACHINE_START_ADDRESS (_dl_loaded
, entry
);
205 _dl_start_final (void *arg
, struct link_map
*bootstrap_map_p
,
206 hp_timing_t start_time
)
208 /* The use of `alloca' here looks ridiculous but it helps. The goal
209 is to avoid the function from being inlined. There is no official
210 way to do this so we use this trick. gcc never inlines functions
211 which use `alloca'. */
212 ElfW(Addr
) *start_addr
= alloca (sizeof (ElfW(Addr
)));
216 /* If it hasn't happen yet record the startup time. */
217 if (! HP_TIMING_INLINE
)
218 HP_TIMING_NOW (start_time
);
220 /* Initialize the timing functions. */
221 HP_TIMING_DIFF_INIT ();
224 /* Transfer data about ourselves to the permanent link_map structure. */
225 _dl_rtld_map
.l_addr
= bootstrap_map_p
->l_addr
;
226 _dl_rtld_map
.l_ld
= bootstrap_map_p
->l_ld
;
227 _dl_rtld_map
.l_opencount
= 1;
228 memcpy (_dl_rtld_map
.l_info
, bootstrap_map_p
->l_info
,
229 sizeof _dl_rtld_map
.l_info
);
230 _dl_setup_hash (&_dl_rtld_map
);
232 /* Don't bother trying to work out how ld.so is mapped in memory. */
233 _dl_rtld_map
.l_map_start
= ~0;
234 _dl_rtld_map
.l_map_end
= ~0;
236 /* Call the OS-dependent function to set up life so we can do things like
237 file access. It will call `dl_main' (below) to do all the real work
238 of the dynamic linker, and then unwind our frame and run the user
239 entry point on the same stack we entered on. */
240 *start_addr
= _dl_sysdep_start (arg
, &dl_main
);
241 #ifndef HP_TIMING_NONAVAIL
244 hp_timing_t end_time
;
246 /* Get the current time. */
247 HP_TIMING_NOW (end_time
);
249 /* Compute the difference. */
250 HP_TIMING_DIFF (rtld_total_time
, start_time
, end_time
);
254 if (__builtin_expect (_dl_debug_mask
& DL_DEBUG_STATISTICS
, 0))
260 /* Now life is peachy; we can do all normal operations.
261 On to the real work. */
263 /* Some helper functions. */
265 /* Arguments to relocate_doit. */
274 /* Argument to map_doit. */
276 /* Return value of map_doit. */
277 struct link_map
*main_map
;
280 /* Arguments to version_check_doit. */
281 struct version_check_args
288 relocate_doit (void *a
)
290 struct relocate_args
*args
= (struct relocate_args
*) a
;
292 _dl_relocate_object (args
->l
, args
->l
->l_scope
,
299 struct map_args
*args
= (struct map_args
*) a
;
300 args
->main_map
= _dl_map_object (NULL
, args
->str
, 0, lt_library
, 0, 0);
304 version_check_doit (void *a
)
306 struct version_check_args
*args
= (struct version_check_args
*) a
;
307 if (_dl_check_all_versions (_dl_loaded
, 1, args
->dotrace
) && args
->doexit
)
308 /* We cannot start the application. Abort now. */
313 static inline struct link_map
*
314 find_needed (const char *name
)
316 unsigned int n
= _dl_loaded
->l_searchlist
.r_nlist
;
319 if (_dl_name_match_p (name
, _dl_loaded
->l_searchlist
.r_list
[n
]))
320 return _dl_loaded
->l_searchlist
.r_list
[n
];
322 /* Should never happen. */
327 match_version (const char *string
, struct link_map
*map
)
329 const char *strtab
= (const void *) D_PTR (map
, l_info
[DT_STRTAB
]);
332 #define VERDEFTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERDEF))
333 if (map
->l_info
[VERDEFTAG
] == NULL
)
334 /* The file has no symbol versioning. */
337 def
= (ElfW(Verdef
) *) ((char *) map
->l_addr
338 + map
->l_info
[VERDEFTAG
]->d_un
.d_ptr
);
341 ElfW(Verdaux
) *aux
= (ElfW(Verdaux
) *) ((char *) def
+ def
->vd_aux
);
343 /* Compare the version strings. */
344 if (strcmp (string
, strtab
+ aux
->vda_name
) == 0)
348 /* If no more definitions we failed to find what we want. */
349 if (def
->vd_next
== 0)
352 /* Next definition. */
353 def
= (ElfW(Verdef
) *) ((char *) def
+ def
->vd_next
);
359 static const char *library_path
; /* The library search path. */
360 static const char *preloadlist
; /* The list preloaded objects. */
361 static int version_info
; /* Nonzero if information about
362 versions has to be printed. */
365 dl_main (const ElfW(Phdr
) *phdr
,
367 ElfW(Addr
) *user_entry
)
369 const ElfW(Phdr
) *ph
;
371 struct link_map
**preloads
;
372 unsigned int npreloads
;
377 int rtld_is_main
= 0;
378 #ifndef HP_TIMING_NONAVAIL
384 /* Process the environment variable which control the behaviour. */
385 process_envvars (&mode
);
387 /* Set up a flag which tells we are just starting. */
390 if (*user_entry
== (ElfW(Addr
)) ENTRY_POINT
)
392 /* Ho ho. We are not the program interpreter! We are the program
393 itself! This means someone ran ld.so as a command. Well, that
394 might be convenient to do sometimes. We support it by
395 interpreting the args like this:
397 ld.so PROGRAM ARGS...
399 The first argument is the name of a file containing an ELF
400 executable we will load and run with the following arguments.
401 To simplify life here, PROGRAM is searched for using the
402 normal rules for shared objects, rather than $PATH or anything
403 like that. We just load it and use its entry point; we don't
404 pay attention to its PT_INTERP command (we are the interpreter
405 ourselves). This is an easy way to test a new ld.so before
409 /* Note the place where the dynamic linker actually came from. */
410 _dl_rtld_map
.l_name
= _dl_argv
[0];
413 if (! strcmp (_dl_argv
[1], "--list"))
416 _dl_lazy
= -1; /* This means do no dependency analysis. */
422 else if (! strcmp (_dl_argv
[1], "--verify"))
430 else if (! strcmp (_dl_argv
[1], "--library-path") && _dl_argc
> 2)
432 library_path
= _dl_argv
[2];
438 else if (! strcmp (_dl_argv
[1], "--inhibit-rpath") && _dl_argc
> 2)
440 _dl_inhibit_rpath
= _dl_argv
[2];
449 /* If we have no further argument the program was called incorrectly.
450 Grant the user some education. */
453 Usage: ld.so [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\
454 You have invoked `ld.so', the helper program for shared library executables.\n\
455 This program usually lives in the file `/lib/ld.so', and special directives\n\
456 in executable files using ELF shared libraries tell the system's program\n\
457 loader to load the helper program from this file. This helper program loads\n\
458 the shared libraries needed by the program executable, prepares the program\n\
459 to run, and runs it. You may invoke this helper program directly from the\n\
460 command line to load and run an ELF executable file; this is like executing\n\
461 that file itself, but always uses this helper program from the file you\n\
462 specified, instead of the helper program file specified in the executable\n\
463 file you run. This is mostly of use for maintainers to test new versions\n\
464 of this helper program; chances are you did not intend to run this program.\n\
466 --list list all dependencies and how they are resolved\n\
467 --verify verify that given object really is a dynamically linked\n\
468 object we can handle\n\
469 --library-path PATH use given PATH instead of content of the environment\n\
470 variable LD_LIBRARY_PATH\n\
471 --inhibit-rpath LIST ignore RUNPATH and RPATH information in object names\n\
478 /* Initialize the data structures for the search paths for shared
480 _dl_init_paths (library_path
);
482 if (__builtin_expect (mode
, normal
) == verify
)
485 const char *err_str
= NULL
;
486 struct map_args args
;
488 args
.str
= _dl_argv
[0];
489 (void) _dl_catch_error (&objname
, &err_str
, map_doit
, &args
);
490 if (__builtin_expect (err_str
!= NULL
, 0))
492 if (err_str
!= _dl_out_of_memory
)
493 free ((char *) err_str
);
494 _exit (EXIT_FAILURE
);
499 HP_TIMING_NOW (start
);
500 _dl_map_object (NULL
, _dl_argv
[0], 0, lt_library
, 0, 0);
501 HP_TIMING_NOW (stop
);
503 HP_TIMING_DIFF (load_time
, start
, stop
);
506 phdr
= _dl_loaded
->l_phdr
;
507 phnum
= _dl_loaded
->l_phnum
;
508 /* We overwrite here a pointer to a malloc()ed string. But since
509 the malloc() implementation used at this point is the dummy
510 implementations which has no real free() function it does not
511 makes sense to free the old string first. */
512 _dl_loaded
->l_name
= (char *) "";
513 *user_entry
= _dl_loaded
->l_entry
;
517 /* Create a link_map for the executable itself.
518 This will be what dlopen on "" returns. */
519 _dl_new_object ((char *) "", "", lt_executable
, NULL
);
520 if (_dl_loaded
== NULL
)
521 _dl_fatal_printf ("cannot allocate memory for link map\n");
522 _dl_loaded
->l_phdr
= phdr
;
523 _dl_loaded
->l_phnum
= phnum
;
524 _dl_loaded
->l_entry
= *user_entry
;
526 /* At this point we are in a bit of trouble. We would have to
527 fill in the values for l_dev and l_ino. But in general we
528 do not know where the file is. We also do not handle AT_EXECFD
529 even if it would be passed up.
531 We leave the values here defined to 0. This is normally no
532 problem as the program code itself is normally no shared
533 object and therefore cannot be loaded dynamically. Nothing
534 prevent the use of dynamic binaries and in these situations
535 we might get problems. We might not be able to find out
536 whether the object is already loaded. But since there is no
537 easy way out and because the dynamic binary must also not
538 have an SONAME we ignore this program for now. If it becomes
539 a problem we can force people using SONAMEs. */
541 /* We delay initializing the path structure until we got the dynamic
542 information for the program. */
545 /* It is not safe to load stuff after the main program. */
546 _dl_loaded
->l_map_end
= ~0;
547 /* Perhaps the executable has no PT_LOAD header entries at all. */
548 _dl_loaded
->l_map_start
= ~0;
550 /* Scan the program header table for the dynamic section. */
551 for (ph
= phdr
; ph
< &phdr
[phnum
]; ++ph
)
555 /* Find out the load address. */
556 _dl_loaded
->l_addr
= (ElfW(Addr
)) phdr
- ph
->p_vaddr
;
559 /* This tells us where to find the dynamic section,
560 which tells us everything we need to do. */
561 _dl_loaded
->l_ld
= (void *) _dl_loaded
->l_addr
+ ph
->p_vaddr
;
564 /* This "interpreter segment" was used by the program loader to
565 find the program interpreter, which is this program itself, the
566 dynamic linker. We note what name finds us, so that a future
567 dlopen call or DT_NEEDED entry, for something that wants to link
568 against the dynamic linker as a shared library, will know that
569 the shared object is already loaded. */
570 _dl_rtld_libname
.name
= ((const char *) _dl_loaded
->l_addr
572 /* _dl_rtld_libname.next = NULL; Already zero. */
573 _dl_rtld_map
.l_libname
= &_dl_rtld_libname
;
575 /* Ordinarilly, we would get additional names for the loader from
576 our DT_SONAME. This can't happen if we were actually linked as
577 a static executable (detect this case when we have no DYNAMIC).
578 If so, assume the filename component of the interpreter path to
579 be our SONAME, and add it to our name list. */
580 if (_dl_rtld_map
.l_ld
== NULL
)
582 char *p
= strrchr (_dl_rtld_libname
.name
, '/');
585 _dl_rtld_libname2
.name
= p
+1;
586 /* _dl_rtld_libname2.next = NULL; Already zero. */
587 _dl_rtld_libname
.next
= &_dl_rtld_libname2
;
594 /* Remember where the main program starts in memory. */
597 mapstart
= _dl_loaded
->l_addr
+ (ph
->p_vaddr
& ~(ph
->p_align
- 1));
598 if (_dl_loaded
->l_map_start
> mapstart
)
599 _dl_loaded
->l_map_start
= mapstart
;
603 if (! _dl_rtld_map
.l_libname
&& _dl_rtld_map
.l_name
)
605 /* We were invoked directly, so the program might not have a
607 _dl_rtld_libname
.name
= _dl_rtld_map
.l_name
;
608 /* _dl_rtld_libname.next = NULL; Alread zero. */
609 _dl_rtld_map
.l_libname
= &_dl_rtld_libname
;
612 assert (_dl_rtld_map
.l_libname
); /* How else did we get here? */
616 /* Extract the contents of the dynamic section for easy access. */
617 elf_get_dynamic_info (_dl_loaded
);
618 if (_dl_loaded
->l_info
[DT_HASH
])
619 /* Set up our cache of pointers into the hash table. */
620 _dl_setup_hash (_dl_loaded
);
623 if (__builtin_expect (mode
, normal
) == verify
)
625 /* We were called just to verify that this is a dynamic
626 executable using us as the program interpreter. Exit with an
627 error if we were not able to load the binary or no interpreter
628 is specified (i.e., this is no dynamically linked binary. */
629 if (_dl_loaded
->l_ld
== NULL
)
632 /* We allow here some platform specific code. */
633 #ifdef DISTINGUISH_LIB_VERSIONS
634 DISTINGUISH_LIB_VERSIONS
;
636 _exit (has_interp
? 0 : 2);
640 /* Initialize the data structures for the search paths for shared
642 _dl_init_paths (library_path
);
644 /* Put the link_map for ourselves on the chain so it can be found by
645 name. Note that at this point the global chain of link maps contains
646 exactly one element, which is pointed to by _dl_loaded. */
647 if (! _dl_rtld_map
.l_name
)
648 /* If not invoked directly, the dynamic linker shared object file was
649 found by the PT_INTERP name. */
650 _dl_rtld_map
.l_name
= (char *) _dl_rtld_map
.l_libname
->name
;
651 _dl_rtld_map
.l_type
= lt_library
;
652 _dl_loaded
->l_next
= &_dl_rtld_map
;
653 _dl_rtld_map
.l_prev
= _dl_loaded
;
656 /* We have two ways to specify objects to preload: via environment
657 variable and via the file /etc/ld.so.preload. The latter can also
658 be used when security is enabled. */
662 if (__builtin_expect (preloadlist
!= NULL
, 0))
664 /* The LD_PRELOAD environment variable gives list of libraries
665 separated by white space or colons that are loaded before the
666 executable's dependencies and prepended to the global scope
667 list. If the binary is running setuid all elements
668 containing a '/' are ignored since it is insecure. */
669 char *list
= strdupa (preloadlist
);
672 HP_TIMING_NOW (start
);
674 while ((p
= strsep (&list
, " :")) != NULL
)
676 && (__builtin_expect (! __libc_enable_secure
, 1)
677 || strchr (p
, '/') == NULL
))
679 struct link_map
*new_map
= _dl_map_object (_dl_loaded
, p
, 1,
681 if (++new_map
->l_opencount
== 1)
682 /* It is no duplicate. */
686 HP_TIMING_NOW (stop
);
687 HP_TIMING_DIFF (diff
, start
, stop
);
688 HP_TIMING_ACCUM_NT (load_time
, diff
);
691 /* Read the contents of the file. */
692 file
= _dl_sysdep_read_whole_file ("/etc/ld.so.preload", &file_size
,
693 PROT_READ
| PROT_WRITE
);
694 if (__builtin_expect (file
!= NULL
, 0))
696 /* Parse the file. It contains names of libraries to be loaded,
697 separated by white spaces or `:'. It may also contain
698 comments introduced by `#'. */
703 /* Eliminate comments. */
708 char *comment
= memchr (runp
, '#', rest
);
712 rest
-= comment
- runp
;
715 while (--rest
> 0 && *++comment
!= '\n');
718 /* We have one problematic case: if we have a name at the end of
719 the file without a trailing terminating characters, we cannot
720 place the \0. Handle the case separately. */
721 if (file
[file_size
- 1] != ' ' && file
[file_size
- 1] != '\t'
722 && file
[file_size
- 1] != '\n' && file
[file_size
- 1] != ':')
724 problem
= &file
[file_size
];
725 while (problem
> file
&& problem
[-1] != ' ' && problem
[-1] != '\t'
726 && problem
[-1] != '\n' && problem
[-1] != ':')
735 file
[file_size
- 1] = '\0';
738 HP_TIMING_NOW (start
);
744 while ((p
= strsep (&runp
, ": \t\n")) != NULL
)
747 struct link_map
*new_map
= _dl_map_object (_dl_loaded
, p
, 1,
749 if (++new_map
->l_opencount
== 1)
750 /* It is no duplicate. */
757 char *p
= strndupa (problem
, file_size
- (problem
- file
));
758 struct link_map
*new_map
= _dl_map_object (_dl_loaded
, p
, 1,
760 if (++new_map
->l_opencount
== 1)
761 /* It is no duplicate. */
765 HP_TIMING_NOW (stop
);
766 HP_TIMING_DIFF (diff
, start
, stop
);
767 HP_TIMING_ACCUM_NT (load_time
, diff
);
769 /* We don't need the file anymore. */
770 __munmap (file
, file_size
);
773 if (__builtin_expect (npreloads
, 0) != 0)
775 /* Set up PRELOADS with a vector of the preloaded libraries. */
777 preloads
= __alloca (npreloads
* sizeof preloads
[0]);
778 l
= _dl_rtld_map
.l_next
; /* End of the chain before preloads. */
785 assert (i
== npreloads
);
788 /* Load all the libraries specified by DT_NEEDED entries. If LD_PRELOAD
789 specified some libraries to load, these are inserted before the actual
790 dependencies in the executable's searchlist for symbol resolution. */
791 HP_TIMING_NOW (start
);
792 _dl_map_object_deps (_dl_loaded
, preloads
, npreloads
, mode
== trace
);
793 HP_TIMING_NOW (stop
);
794 HP_TIMING_DIFF (diff
, start
, stop
);
795 HP_TIMING_ACCUM_NT (load_time
, diff
);
797 /* Mark all objects as being in the global scope and set the open
799 for (i
= _dl_loaded
->l_searchlist
.r_nlist
; i
> 0; )
802 _dl_loaded
->l_searchlist
.r_list
[i
]->l_global
= 1;
803 ++_dl_loaded
->l_searchlist
.r_list
[i
]->l_opencount
;
807 /* We are done mapping things, so close the zero-fill descriptor. */
808 __close (_dl_zerofd
);
812 /* Remove _dl_rtld_map from the chain. */
813 _dl_rtld_map
.l_prev
->l_next
= _dl_rtld_map
.l_next
;
814 if (_dl_rtld_map
.l_next
)
815 _dl_rtld_map
.l_next
->l_prev
= _dl_rtld_map
.l_prev
;
817 if (__builtin_expect (_dl_rtld_map
.l_opencount
, 2) > 1)
819 /* Some DT_NEEDED entry referred to the interpreter object itself, so
820 put it back in the list of visible objects. We insert it into the
821 chain in symbol search order because gdb uses the chain's order as
822 its symbol search order. */
824 while (_dl_loaded
->l_searchlist
.r_list
[i
] != &_dl_rtld_map
)
826 _dl_rtld_map
.l_prev
= _dl_loaded
->l_searchlist
.r_list
[i
- 1];
827 if (__builtin_expect (mode
, normal
) == normal
)
828 _dl_rtld_map
.l_next
= (i
+ 1 < _dl_loaded
->l_searchlist
.r_nlist
829 ? _dl_loaded
->l_searchlist
.r_list
[i
+ 1]
832 /* In trace mode there might be an invisible object (which we
833 could not find) after the previous one in the search list.
834 In this case it doesn't matter much where we put the
835 interpreter object, so we just initialize the list pointer so
836 that the assertion below holds. */
837 _dl_rtld_map
.l_next
= _dl_rtld_map
.l_prev
->l_next
;
839 assert (_dl_rtld_map
.l_prev
->l_next
== _dl_rtld_map
.l_next
);
840 _dl_rtld_map
.l_prev
->l_next
= &_dl_rtld_map
;
841 if (_dl_rtld_map
.l_next
)
843 assert (_dl_rtld_map
.l_next
->l_prev
== _dl_rtld_map
.l_prev
);
844 _dl_rtld_map
.l_next
->l_prev
= &_dl_rtld_map
;
848 /* Now let us see whether all libraries are available in the
851 struct version_check_args args
;
852 args
.doexit
= mode
== normal
;
853 args
.dotrace
= mode
== trace
;
854 _dl_receive_error (print_missing_version
, version_check_doit
, &args
);
857 if (__builtin_expect (mode
, normal
) != normal
)
859 /* We were run just to list the shared libraries. It is
860 important that we do this before real relocation, because the
861 functions we call below for output may no longer work properly
863 if (! _dl_loaded
->l_info
[DT_NEEDED
])
864 _dl_printf ("\tstatically linked\n");
869 for (l
= _dl_loaded
->l_next
; l
; l
= l
->l_next
)
871 /* The library was not found. */
872 _dl_printf ("\t%s => not found\n", l
->l_libname
->name
);
874 _dl_printf ("\t%s => %s (0x%0*Zx)\n", l
->l_libname
->name
,
875 l
->l_name
, (int) sizeof l
->l_addr
* 2, l
->l_addr
);
878 if (__builtin_expect (mode
, trace
) != trace
)
879 for (i
= 1; i
< _dl_argc
; ++i
)
881 const ElfW(Sym
) *ref
= NULL
;
885 result
= _dl_lookup_symbol (_dl_argv
[i
], _dl_loaded
,
886 &ref
, _dl_loaded
->l_scope
,
887 ELF_MACHINE_JMP_SLOT
, 1);
889 loadbase
= LOOKUP_VALUE_ADDRESS (result
);
891 _dl_printf ("%s found at 0x%0*Zd in object at 0x%0*Zd\n",
893 (int) sizeof ref
->st_value
* 2, ref
->st_value
,
894 (int) sizeof loadbase
* 2, loadbase
);
898 /* If LD_WARN is set warn about undefined symbols. */
899 if (_dl_lazy
>= 0 && _dl_verbose
)
901 /* We have to do symbol dependency testing. */
902 struct relocate_args args
;
905 args
.lazy
= _dl_lazy
;
912 if (l
!= &_dl_rtld_map
&& ! l
->l_faked
)
915 _dl_receive_error (print_unresolved
, relocate_doit
,
922 #define VERNEEDTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERNEED))
925 /* Print more information. This means here, print information
926 about the versions needed. */
928 struct link_map
*map
= _dl_loaded
;
930 for (map
= _dl_loaded
; map
!= NULL
; map
= map
->l_next
)
933 ElfW(Dyn
) *dyn
= map
->l_info
[VERNEEDTAG
];
939 strtab
= (const void *) D_PTR (map
, l_info
[DT_STRTAB
]);
940 ent
= (ElfW(Verneed
) *) (map
->l_addr
+ dyn
->d_un
.d_ptr
);
944 _dl_printf ("\n\tVersion information:\n");
948 _dl_printf ("\t%s:\n",
949 map
->l_name
[0] ? map
->l_name
: _dl_argv
[0]);
954 struct link_map
*needed
;
956 needed
= find_needed (strtab
+ ent
->vn_file
);
957 aux
= (ElfW(Vernaux
) *) ((char *) ent
+ ent
->vn_aux
);
961 const char *fname
= NULL
;
964 && match_version (strtab
+ aux
->vna_name
,
966 fname
= needed
->l_name
;
968 _dl_printf ("\t\t%s (%s) %s=> %s\n",
969 strtab
+ ent
->vn_file
,
970 strtab
+ aux
->vna_name
,
971 aux
->vna_flags
& VER_FLG_WEAK
973 fname
?: "not found");
975 if (aux
->vna_next
== 0)
976 /* No more symbols. */
980 aux
= (ElfW(Vernaux
) *) ((char *) aux
984 if (ent
->vn_next
== 0)
985 /* No more dependencies. */
988 /* Next dependency. */
989 ent
= (ElfW(Verneed
) *) ((char *) ent
+ ent
->vn_next
);
999 /* Now we have all the objects loaded. Relocate them all except for
1000 the dynamic linker itself. We do this in reverse order so that copy
1001 relocs of earlier objects overwrite the data written by later
1002 objects. We do not re-relocate the dynamic linker itself in this
1003 loop because that could result in the GOT entries for functions we
1004 call being changed, and that would break us. It is safe to relocate
1005 the dynamic linker out of order because it has no copy relocs (we
1006 know that because it is self-contained). */
1009 int consider_profiling
= _dl_profile
!= NULL
;
1010 #ifndef HP_TIMING_NONAVAIL
1016 /* If we are profiling we also must do lazy reloaction. */
1017 _dl_lazy
|= consider_profiling
;
1023 HP_TIMING_NOW (start
);
1026 /* While we are at it, help the memory handling a bit. We have to
1027 mark some data structures as allocated with the fake malloc()
1028 implementation in ld.so. */
1029 struct libname_list
*lnp
= l
->l_libname
->next
;
1031 while (__builtin_expect (lnp
!= NULL
, 0))
1037 if (l
!= &_dl_rtld_map
)
1038 _dl_relocate_object (l
, l
->l_scope
, _dl_lazy
, consider_profiling
);
1043 HP_TIMING_NOW (stop
);
1045 HP_TIMING_DIFF (relocate_time
, start
, stop
);
1047 /* Do any necessary cleanups for the startup OS interface code.
1048 We do these now so that no calls are made after rtld re-relocation
1049 which might be resolved to different functions than we expect.
1050 We cannot do this before relocating the other objects because
1051 _dl_relocate_object might need to call `mprotect' for DT_TEXTREL. */
1052 _dl_sysdep_start_cleanup ();
1054 /* Now enable profiling if needed. Like the previous call,
1055 this has to go here because the calls it makes should use the
1056 rtld versions of the functions (particularly calloc()), but it
1057 needs to have _dl_profile_map set up by the relocator. */
1058 if (__builtin_expect (_dl_profile_map
!= NULL
, 0))
1059 /* We must prepare the profiling. */
1060 _dl_start_profile (_dl_profile_map
, _dl_profile_output
);
1062 if (_dl_rtld_map
.l_opencount
> 1)
1064 /* There was an explicit ref to the dynamic linker as a shared lib.
1065 Re-relocate ourselves with user-controlled symbol definitions. */
1066 HP_TIMING_NOW (start
);
1067 _dl_relocate_object (&_dl_rtld_map
, _dl_loaded
->l_scope
, 0, 0);
1068 HP_TIMING_NOW (stop
);
1069 HP_TIMING_DIFF (add
, start
, stop
);
1070 HP_TIMING_ACCUM_NT (relocate_time
, add
);
1074 /* Now set up the variable which helps the assembler startup code. */
1075 _dl_main_searchlist
= &_dl_loaded
->l_searchlist
;
1076 _dl_global_scope
[0] = &_dl_loaded
->l_searchlist
;
1078 /* Safe the information about the original global scope list since
1079 we need it in the memory handling later. */
1080 _dl_initial_searchlist
= *_dl_main_searchlist
;
1083 /* Initialize _r_debug. */
1084 struct r_debug
*r
= _dl_debug_initialize (_dl_rtld_map
.l_addr
);
1089 #ifdef ELF_MACHINE_DEBUG_SETUP
1091 /* Some machines (e.g. MIPS) don't use DT_DEBUG in this way. */
1093 ELF_MACHINE_DEBUG_SETUP (l
, r
);
1094 ELF_MACHINE_DEBUG_SETUP (&_dl_rtld_map
, r
);
1098 if (l
->l_info
[DT_DEBUG
])
1099 /* There is a DT_DEBUG entry in the dynamic section. Fill it in
1100 with the run-time address of the r_debug structure */
1101 l
->l_info
[DT_DEBUG
]->d_un
.d_ptr
= (ElfW(Addr
)) r
;
1103 /* Fill in the pointer in the dynamic linker's own dynamic section, in
1104 case you run gdb on the dynamic linker directly. */
1105 if (_dl_rtld_map
.l_info
[DT_DEBUG
])
1106 _dl_rtld_map
.l_info
[DT_DEBUG
]->d_un
.d_ptr
= (ElfW(Addr
)) r
;
1110 /* Notify the debugger that all objects are now mapped in. */
1111 r
->r_state
= RT_ADD
;
1116 /* We must munmap() the cache file. */
1117 _dl_unload_cache ();
1120 /* Once we return, _dl_sysdep_start will invoke
1121 the DT_INIT functions and then *USER_ENTRY. */
1124 /* This is a little helper function for resolving symbols while
1125 tracing the binary. */
1127 print_unresolved (int errcode
__attribute__ ((unused
)), const char *objname
,
1128 const char *errstring
)
1130 if (objname
[0] == '\0')
1131 objname
= _dl_argv
[0] ?: "<main program>";
1132 _dl_error_printf ("%s (%s)\n", errstring
, objname
);
1135 /* This is a little helper function for resolving symbols while
1136 tracing the binary. */
1138 print_missing_version (int errcode
__attribute__ ((unused
)),
1139 const char *objname
, const char *errstring
)
1141 _dl_error_printf ("%s: %s: %s\n", _dl_argv
[0] ?: "<program name unknown>",
1142 objname
, errstring
);
1145 /* Nonzero if any of the debugging options is enabled. */
1146 static int any_debug
;
1148 /* Process the string given as the parameter which explains which debugging
1149 options are enabled. */
1151 process_dl_debug (const char *dl_debug
)
1154 #define separators " ,:"
1158 /* Skip separating white spaces and commas. */
1159 dl_debug
+= strspn (dl_debug
, separators
);
1160 if (*dl_debug
!= '\0')
1162 len
= strcspn (dl_debug
, separators
);
1167 /* This option is not documented since it is not generally
1169 if (memcmp (dl_debug
, "all", 3) == 0)
1171 _dl_debug_mask
= (DL_DEBUG_LIBS
| DL_DEBUG_IMPCALLS
1172 | DL_DEBUG_RELOC
| DL_DEBUG_FILES
1173 | DL_DEBUG_SYMBOLS
| DL_DEBUG_BINDINGS
1174 | DL_DEBUG_VERSIONS
);
1181 if (memcmp (dl_debug
, "help", 4) == 0)
1184 Valid options for the LD_DEBUG environment variable are:\n\
1186 bindings display information about symbol binding\n\
1187 files display processing of files and libraries\n\
1188 help display this help message and exit\n\
1189 libs display library search paths\n\
1190 reloc display relocation processing\n\
1191 statistics display relocation statistics\n\
1192 symbols display symbol table processing\n\
1193 versions display version dependencies\n\
1195 To direct the debugging output into a file instead of standard output\n\
1196 a filename can be specified using the LD_DEBUG_OUTPUT environment variable.\n");
1200 if (memcmp (dl_debug
, "libs", 4) == 0)
1202 _dl_debug_mask
|= DL_DEBUG_LIBS
| DL_DEBUG_IMPCALLS
;
1209 if (memcmp (dl_debug
, "reloc", 5) == 0)
1211 _dl_debug_mask
|= DL_DEBUG_RELOC
| DL_DEBUG_IMPCALLS
;
1216 if (memcmp (dl_debug
, "files", 5) == 0)
1218 _dl_debug_mask
|= DL_DEBUG_FILES
| DL_DEBUG_IMPCALLS
;
1225 if (memcmp (dl_debug
, "symbols", 7) == 0)
1227 _dl_debug_mask
|= DL_DEBUG_SYMBOLS
| DL_DEBUG_IMPCALLS
;
1234 if (memcmp (dl_debug
, "bindings", 8) == 0)
1236 _dl_debug_mask
|= DL_DEBUG_BINDINGS
| DL_DEBUG_IMPCALLS
;
1241 if (memcmp (dl_debug
, "versions", 8) == 0)
1243 _dl_debug_mask
|= DL_DEBUG_VERSIONS
| DL_DEBUG_IMPCALLS
;
1250 if (memcmp (dl_debug
, "statistics", 10) == 0)
1252 _dl_debug_mask
|= DL_DEBUG_STATISTICS
;
1262 /* Display a warning and skip everything until next separator. */
1263 char *startp
= strndupa (dl_debug
, len
);
1264 _dl_error_printf ("\
1265 warning: debug option `%s' unknown; try LD_DEBUG=help\n", startp
);
1270 while (*(dl_debug
+= len
) != '\0');
1273 /* Process all environments variables the dynamic linker must recognize.
1274 Since all of them start with `LD_' we are a bit smarter while finding
1277 process_envvars (enum mode
*modep
)
1281 enum mode mode
= normal
;
1282 char *debug_output
= NULL
;
1284 /* This is the default place for profiling data file. */
1285 _dl_profile_output
= __libc_enable_secure
? "/var/profile" : "/var/tmp";
1287 while ((envline
= _dl_next_ld_env_entry (&runp
)) != NULL
)
1289 size_t len
= strcspn (envline
, "=");
1291 if (envline
[len
] != '=')
1292 /* This is a "LD_" variable at the end of the string without
1293 a '=' character. Ignore it since otherwise we will access
1294 invalid memory below. */
1300 /* Warning level, verbose or not. */
1301 if (memcmp (&envline
[3], "WARN", 4) == 0)
1302 _dl_verbose
= envline
[8] != '\0';
1306 /* Debugging of the dynamic linker? */
1307 if (memcmp (&envline
[3], "DEBUG", 5) == 0)
1308 process_dl_debug (&envline
[9]);
1312 /* Print information about versions. */
1313 if (memcmp (&envline
[3], "VERBOSE", 7) == 0)
1315 version_info
= envline
[11] != '\0';
1319 /* List of objects to be preloaded. */
1320 if (memcmp (&envline
[3], "PRELOAD", 7) == 0)
1322 preloadlist
= &envline
[11];
1326 /* Which shared object shall be profiled. */
1327 if (memcmp (&envline
[3], "PROFILE", 7) == 0)
1328 _dl_profile
= &envline
[11];
1332 /* Do we bind early? */
1333 if (memcmp (&envline
[3], "BIND_NOW", 8) == 0)
1335 _dl_lazy
= envline
[12] == '\0';
1338 if (memcmp (&envline
[3], "BIND_NOT", 8) == 0)
1339 _dl_bind_not
= envline
[12] != '\0';
1343 /* Test whether we want to see the content of the auxiliary
1344 array passed up from the kernel. */
1345 if (memcmp (&envline
[3], "SHOW_AUXV", 9) == 0)
1350 /* Mask for the important hardware capabilities. */
1351 if (memcmp (&envline
[3], "HWCAP_MASK", 10) == 0)
1352 _dl_hwcap_mask
= __strtoul_internal (&envline
[14], NULL
, 0, 0);
1356 /* Path where the binary is found. */
1357 if (!__libc_enable_secure
1358 && memcmp (&envline
[3], "ORIGIN_PATH", 11) == 0)
1359 _dl_origin_path
= &envline
[15];
1363 /* The library search path. */
1364 if (memcmp (&envline
[3], "LIBRARY_PATH", 12) == 0)
1366 library_path
= &envline
[16];
1370 /* Where to place the profiling data file. */
1371 if (memcmp (&envline
[3], "DEBUG_OUTPUT", 12) == 0)
1373 debug_output
= &envline
[16];
1377 if (memcmp (&envline
[3], "DYNAMIC_WEAK", 12) == 0)
1378 _dl_dynamic_weak
= 1;
1382 /* Where to place the profiling data file. */
1383 if (!__libc_enable_secure
1384 && memcmp (&envline
[3], "PROFILE_OUTPUT", 14) == 0)
1386 _dl_profile_output
= &envline
[18];
1387 if (*_dl_profile_output
== '\0')
1388 _dl_profile_output
= "/var/tmp";
1393 /* The mode of the dynamic linker can be set. */
1394 if (memcmp (&envline
[3], "TRACE_LOADED_OBJECTS", 20) == 0)
1398 /* We might have some extra environment variable to handle. This
1399 is tricky due to the pre-processing of the length of the name
1400 in the switch statement here. The code here assumes that added
1401 environment variables have a different length. */
1402 #ifdef EXTRA_LD_ENVVARS
1408 /* Extra security for SUID binaries. Remove all dangerous environment
1410 if (__builtin_expect (__libc_enable_secure
, 0))
1412 static const char *unsecure_envvars
[] =
1415 #ifdef EXTRA_UNSECURE_ENVVARS
1416 EXTRA_UNSECURE_ENVVARS
1421 if (preloadlist
!= NULL
)
1422 unsetenv ("LD_PRELOAD");
1423 if (library_path
!= NULL
)
1424 unsetenv ("LD_LIBRARY_PATH");
1425 if (_dl_origin_path
!= NULL
)
1426 unsetenv ("LD_ORIGIN_PATH");
1427 if (debug_output
!= NULL
)
1428 unsetenv ("LD_DEBUG_OUTPUT");
1429 if (_dl_profile
!= NULL
)
1430 unsetenv ("LD_PROFILE");
1433 cnt
< sizeof (unsecure_envvars
) / sizeof (unsecure_envvars
[0]);
1435 unsetenv (unsecure_envvars
[cnt
]);
1437 if (__access ("/etc/suid-debug", F_OK
) != 0)
1438 unsetenv ("MALLOC_CHECK_");
1441 /* The name of the object to profile cannot be empty. */
1442 if (_dl_profile
!= NULL
&& *_dl_profile
== '\0')
1445 /* If we have to run the dynamic linker in debugging mode and the
1446 LD_DEBUG_OUTPUT environment variable is given, we write the debug
1447 messages to this file. */
1448 if (any_debug
&& debug_output
!= NULL
&& !__libc_enable_secure
)
1451 const int flags
= O_WRONLY
| O_APPEND
| O_CREAT
| O_NOFOLLOW
;
1453 const int flags
= O_WRONLY
| O_APPEND
| O_CREAT
;
1455 size_t name_len
= strlen (debug_output
);
1456 char buf
[name_len
+ 12];
1459 buf
[name_len
+ 11] = '\0';
1460 startp
= _itoa_word (__getpid (), &buf
[name_len
+ 11], 10, 0);
1462 startp
= memcpy (startp
- name_len
, debug_output
, name_len
);
1464 _dl_debug_fd
= __open (startp
, flags
, DEFFILEMODE
);
1465 if (_dl_debug_fd
== -1)
1466 /* We use standard output if opening the file failed. */
1467 _dl_debug_fd
= STDOUT_FILENO
;
1474 /* Print the various times we collected. */
1476 print_statistics (void)
1478 #ifndef HP_TIMING_NONAVAIL
1483 /* Total time rtld used. */
1484 if (HP_TIMING_AVAIL
)
1486 HP_TIMING_PRINT (buf
, sizeof (buf
), rtld_total_time
);
1487 _dl_debug_printf ("\nruntime linker statistics:\n"
1488 " total startup time in dynamic loader: %s\n", buf
);
1491 /* Print relocation statistics. */
1492 if (HP_TIMING_AVAIL
)
1495 HP_TIMING_PRINT (buf
, sizeof (buf
), relocate_time
);
1496 cp
= _itoa_word ((1000 * relocate_time
) / rtld_total_time
,
1497 pbuf
+ sizeof (pbuf
), 10, 0);
1499 switch (pbuf
+ sizeof (pbuf
) - cp
)
1510 _dl_debug_printf (" time needed for relocation: %s (%s)\n",
1514 _dl_debug_printf (" number of relocations: %lu\n",
1515 _dl_num_relocations
);
1517 #ifndef HP_TIMING_NONAVAIL
1518 /* Time spend while loading the object and the dependencies. */
1519 if (HP_TIMING_AVAIL
)
1522 HP_TIMING_PRINT (buf
, sizeof (buf
), load_time
);
1523 cp
= _itoa_word ((1000 * load_time
) / rtld_total_time
,
1524 pbuf
+ sizeof (pbuf
), 10, 0);
1526 switch (pbuf
+ sizeof (pbuf
) - cp
)
1537 _dl_debug_printf (" time needed to load objects: %s (%s)\n",