(_POSIX_VERSION, _POSIX2_VERSION, _POSIX2_C_BIND,
[glibc/history.git] / elf / rtld.c
blobaa4c030f730c7b7527969cdc55268b6a58374dfa
1 /* Run time dynamic linker.
2 Copyright (C) 1995-2006, 2007, 2008, 2009 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
18 02111-1307 USA. */
20 #include <errno.h>
21 #include <dlfcn.h>
22 #include <fcntl.h>
23 #include <stdbool.h>
24 #include <stdlib.h>
25 #include <string.h>
26 #include <unistd.h>
27 #include <sys/mman.h> /* Check if MAP_ANON is defined. */
28 #include <sys/param.h>
29 #include <sys/stat.h>
30 #include <ldsodefs.h>
31 #include <stdio-common/_itoa.h>
32 #include <entry.h>
33 #include <fpu_control.h>
34 #include <hp-timing.h>
35 #include <bits/libc-lock.h>
36 #include "dynamic-link.h"
37 #include <dl-librecon.h>
38 #include <unsecvars.h>
39 #include <dl-cache.h>
40 #include <dl-osinfo.h>
41 #include <dl-procinfo.h>
42 #include <tls.h>
44 #include <assert.h>
46 /* Avoid PLT use for our local calls at startup. */
47 extern __typeof (__mempcpy) __mempcpy attribute_hidden;
49 /* GCC has mental blocks about _exit. */
50 extern __typeof (_exit) exit_internal asm ("_exit") attribute_hidden;
51 #define _exit exit_internal
53 /* Helper function to handle errors while resolving symbols. */
54 static void print_unresolved (int errcode, const char *objname,
55 const char *errsting);
57 /* Helper function to handle errors when a version is missing. */
58 static void print_missing_version (int errcode, const char *objname,
59 const char *errsting);
61 /* Print the various times we collected. */
62 static void print_statistics (hp_timing_t *total_timep);
64 /* Add audit objects. */
65 static void process_dl_audit (char *str);
67 /* This is a list of all the modes the dynamic loader can be in. */
68 enum mode { normal, list, verify, trace };
70 /* Process all environments variables the dynamic linker must recognize.
71 Since all of them start with `LD_' we are a bit smarter while finding
72 all the entries. */
73 static void process_envvars (enum mode *modep);
75 #ifdef DL_ARGV_NOT_RELRO
76 int _dl_argc attribute_hidden;
77 char **_dl_argv = NULL;
78 /* Nonzero if we were run directly. */
79 unsigned int _dl_skip_args attribute_hidden;
80 #else
81 int _dl_argc attribute_relro attribute_hidden;
82 char **_dl_argv attribute_relro = NULL;
83 unsigned int _dl_skip_args attribute_relro attribute_hidden;
84 #endif
85 INTDEF(_dl_argv)
87 #ifndef THREAD_SET_STACK_GUARD
88 /* Only exported for architectures that don't store the stack guard canary
89 in thread local area. */
90 uintptr_t __stack_chk_guard attribute_relro;
91 #endif
93 /* Only exported for architectures that don't store the pointer guard
94 value in thread local area. */
95 uintptr_t __pointer_chk_guard_local
96 attribute_relro attribute_hidden __attribute__ ((nocommon));
97 #ifndef THREAD_SET_POINTER_GUARD
98 strong_alias (__pointer_chk_guard_local, __pointer_chk_guard)
99 #endif
102 /* List of auditing DSOs. */
103 static struct audit_list
105 const char *name;
106 struct audit_list *next;
107 } *audit_list;
109 #ifndef HAVE_INLINED_SYSCALLS
110 /* Set nonzero during loading and initialization of executable and
111 libraries, cleared before the executable's entry point runs. This
112 must not be initialized to nonzero, because the unused dynamic
113 linker loaded in for libc.so's "ld.so.1" dep will provide the
114 definition seen by libc.so's initializer; that value must be zero,
115 and will be since that dynamic linker's _dl_start and dl_main will
116 never be called. */
117 int _dl_starting_up = 0;
118 INTVARDEF(_dl_starting_up)
119 #endif
121 /* This is the structure which defines all variables global to ld.so
122 (except those which cannot be added for some reason). */
123 struct rtld_global _rtld_global =
125 /* Default presumption without further information is executable stack. */
126 ._dl_stack_flags = PF_R|PF_W|PF_X,
127 #ifdef _LIBC_REENTRANT
128 ._dl_load_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER
129 #endif
131 /* If we would use strong_alias here the compiler would see a
132 non-hidden definition. This would undo the effect of the previous
133 declaration. So spell out was strong_alias does plus add the
134 visibility attribute. */
135 extern struct rtld_global _rtld_local
136 __attribute__ ((alias ("_rtld_global"), visibility ("hidden")));
139 /* This variable is similar to _rtld_local, but all values are
140 read-only after relocation. */
141 struct rtld_global_ro _rtld_global_ro attribute_relro =
143 /* Get architecture specific initializer. */
144 #include <dl-procinfo.c>
145 #ifdef NEED_DL_SYSINFO
146 ._dl_sysinfo = DL_SYSINFO_DEFAULT,
147 #endif
148 ._dl_debug_fd = STDERR_FILENO,
149 ._dl_use_load_bias = -2,
150 ._dl_correct_cache_id = _DL_CACHE_DEFAULT_ID,
151 ._dl_hwcap_mask = HWCAP_IMPORTANT,
152 ._dl_lazy = 1,
153 ._dl_fpu_control = _FPU_DEFAULT,
154 ._dl_pointer_guard = 1,
156 /* Function pointers. */
157 ._dl_debug_printf = _dl_debug_printf,
158 ._dl_catch_error = _dl_catch_error,
159 ._dl_signal_error = _dl_signal_error,
160 ._dl_mcount = _dl_mcount_internal,
161 ._dl_lookup_symbol_x = _dl_lookup_symbol_x,
162 ._dl_check_caller = _dl_check_caller,
163 ._dl_open = _dl_open,
164 ._dl_close = _dl_close,
165 ._dl_tls_get_addr_soft = _dl_tls_get_addr_soft,
166 #ifdef HAVE_DL_DISCOVER_OSVERSION
167 ._dl_discover_osversion = _dl_discover_osversion
168 #endif
170 /* If we would use strong_alias here the compiler would see a
171 non-hidden definition. This would undo the effect of the previous
172 declaration. So spell out was strong_alias does plus add the
173 visibility attribute. */
174 extern struct rtld_global_ro _rtld_local_ro
175 __attribute__ ((alias ("_rtld_global_ro"), visibility ("hidden")));
178 static void dl_main (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
179 ElfW(Addr) *user_entry);
181 /* These two variables cannot be moved into .data.rel.ro. */
182 static struct libname_list _dl_rtld_libname;
183 static struct libname_list _dl_rtld_libname2;
185 /* We expect less than a second for relocation. */
186 #ifdef HP_SMALL_TIMING_AVAIL
187 # undef HP_TIMING_AVAIL
188 # define HP_TIMING_AVAIL HP_SMALL_TIMING_AVAIL
189 #endif
191 /* Variable for statistics. */
192 #ifndef HP_TIMING_NONAVAIL
193 static hp_timing_t relocate_time;
194 static hp_timing_t load_time attribute_relro;
195 static hp_timing_t start_time attribute_relro;
196 #endif
198 /* Additional definitions needed by TLS initialization. */
199 #ifdef TLS_INIT_HELPER
200 TLS_INIT_HELPER
201 #endif
203 /* Helper function for syscall implementation. */
204 #ifdef DL_SYSINFO_IMPLEMENTATION
205 DL_SYSINFO_IMPLEMENTATION
206 #endif
208 /* Before ld.so is relocated we must not access variables which need
209 relocations. This means variables which are exported. Variables
210 declared as static are fine. If we can mark a variable hidden this
211 is fine, too. The latter is important here. We can avoid setting
212 up a temporary link map for ld.so if we can mark _rtld_global as
213 hidden. */
214 #ifdef PI_STATIC_AND_HIDDEN
215 # define DONT_USE_BOOTSTRAP_MAP 1
216 #endif
218 #ifdef DONT_USE_BOOTSTRAP_MAP
219 static ElfW(Addr) _dl_start_final (void *arg);
220 #else
221 struct dl_start_final_info
223 struct link_map l;
224 #if !defined HP_TIMING_NONAVAIL && HP_TIMING_INLINE
225 hp_timing_t start_time;
226 #endif
228 static ElfW(Addr) _dl_start_final (void *arg,
229 struct dl_start_final_info *info);
230 #endif
232 /* These defined magically in the linker script. */
233 extern char _begin[] attribute_hidden;
234 extern char _etext[] attribute_hidden;
235 extern char _end[] attribute_hidden;
238 #ifdef RTLD_START
239 RTLD_START
240 #else
241 # error "sysdeps/MACHINE/dl-machine.h fails to define RTLD_START"
242 #endif
244 #ifndef VALIDX
245 # define VALIDX(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
246 + DT_EXTRANUM + DT_VALTAGIDX (tag))
247 #endif
248 #ifndef ADDRIDX
249 # define ADDRIDX(tag) (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
250 + DT_EXTRANUM + DT_VALNUM + DT_ADDRTAGIDX (tag))
251 #endif
253 /* This is the second half of _dl_start (below). It can be inlined safely
254 under DONT_USE_BOOTSTRAP_MAP, where it is careful not to make any GOT
255 references. When the tools don't permit us to avoid using a GOT entry
256 for _dl_rtld_global (no attribute_hidden support), we must make sure
257 this function is not inlined (see below). */
259 #ifdef DONT_USE_BOOTSTRAP_MAP
260 static inline ElfW(Addr) __attribute__ ((always_inline))
261 _dl_start_final (void *arg)
262 #else
263 static ElfW(Addr) __attribute__ ((noinline))
264 _dl_start_final (void *arg, struct dl_start_final_info *info)
265 #endif
267 ElfW(Addr) start_addr;
269 if (HP_TIMING_AVAIL)
271 /* If it hasn't happen yet record the startup time. */
272 if (! HP_TIMING_INLINE)
273 HP_TIMING_NOW (start_time);
274 #if !defined DONT_USE_BOOTSTRAP_MAP && !defined HP_TIMING_NONAVAIL
275 else
276 start_time = info->start_time;
277 #endif
279 /* Initialize the timing functions. */
280 HP_TIMING_DIFF_INIT ();
283 /* Transfer data about ourselves to the permanent link_map structure. */
284 #ifndef DONT_USE_BOOTSTRAP_MAP
285 GL(dl_rtld_map).l_addr = info->l.l_addr;
286 GL(dl_rtld_map).l_ld = info->l.l_ld;
287 memcpy (GL(dl_rtld_map).l_info, info->l.l_info,
288 sizeof GL(dl_rtld_map).l_info);
289 GL(dl_rtld_map).l_mach = info->l.l_mach;
290 GL(dl_rtld_map).l_relocated = 1;
291 #endif
292 _dl_setup_hash (&GL(dl_rtld_map));
293 GL(dl_rtld_map).l_real = &GL(dl_rtld_map);
294 GL(dl_rtld_map).l_map_start = (ElfW(Addr)) _begin;
295 GL(dl_rtld_map).l_map_end = (ElfW(Addr)) _end;
296 GL(dl_rtld_map).l_text_end = (ElfW(Addr)) _etext;
297 /* Copy the TLS related data if necessary. */
298 #ifndef DONT_USE_BOOTSTRAP_MAP
299 # if USE___THREAD
300 assert (info->l.l_tls_modid != 0);
301 GL(dl_rtld_map).l_tls_blocksize = info->l.l_tls_blocksize;
302 GL(dl_rtld_map).l_tls_align = info->l.l_tls_align;
303 GL(dl_rtld_map).l_tls_firstbyte_offset = info->l.l_tls_firstbyte_offset;
304 GL(dl_rtld_map).l_tls_initimage_size = info->l.l_tls_initimage_size;
305 GL(dl_rtld_map).l_tls_initimage = info->l.l_tls_initimage;
306 GL(dl_rtld_map).l_tls_offset = info->l.l_tls_offset;
307 GL(dl_rtld_map).l_tls_modid = 1;
308 # else
309 # if NO_TLS_OFFSET != 0
310 GL(dl_rtld_map).l_tls_offset = NO_TLS_OFFSET;
311 # endif
312 # endif
314 #endif
316 #if HP_TIMING_AVAIL
317 HP_TIMING_NOW (GL(dl_cpuclock_offset));
318 #endif
320 /* Initialize the stack end variable. */
321 __libc_stack_end = __builtin_frame_address (0);
323 /* Call the OS-dependent function to set up life so we can do things like
324 file access. It will call `dl_main' (below) to do all the real work
325 of the dynamic linker, and then unwind our frame and run the user
326 entry point on the same stack we entered on. */
327 start_addr = _dl_sysdep_start (arg, &dl_main);
329 #ifndef HP_TIMING_NONAVAIL
330 hp_timing_t rtld_total_time;
331 if (HP_TIMING_AVAIL)
333 hp_timing_t end_time;
335 /* Get the current time. */
336 HP_TIMING_NOW (end_time);
338 /* Compute the difference. */
339 HP_TIMING_DIFF (rtld_total_time, start_time, end_time);
341 #endif
343 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_STATISTICS, 0))
345 #ifndef HP_TIMING_NONAVAIL
346 print_statistics (&rtld_total_time);
347 #else
348 print_statistics (NULL);
349 #endif
352 return start_addr;
355 static ElfW(Addr) __attribute_used__ internal_function
356 _dl_start (void *arg)
358 #ifdef DONT_USE_BOOTSTRAP_MAP
359 # define bootstrap_map GL(dl_rtld_map)
360 #else
361 struct dl_start_final_info info;
362 # define bootstrap_map info.l
363 #endif
365 /* This #define produces dynamic linking inline functions for
366 bootstrap relocation instead of general-purpose relocation.
367 Since ld.so must not have any undefined symbols the result
368 is trivial: always the map of ld.so itself. */
369 #define RTLD_BOOTSTRAP
370 #define RESOLVE_MAP(sym, version, flags) (&bootstrap_map)
371 #include "dynamic-link.h"
373 if (HP_TIMING_INLINE && HP_TIMING_AVAIL)
374 #ifdef DONT_USE_BOOTSTRAP_MAP
375 HP_TIMING_NOW (start_time);
376 #else
377 HP_TIMING_NOW (info.start_time);
378 #endif
380 /* Partly clean the `bootstrap_map' structure up. Don't use
381 `memset' since it might not be built in or inlined and we cannot
382 make function calls at this point. Use '__builtin_memset' if we
383 know it is available. We do not have to clear the memory if we
384 do not have to use the temporary bootstrap_map. Global variables
385 are initialized to zero by default. */
386 #ifndef DONT_USE_BOOTSTRAP_MAP
387 # ifdef HAVE_BUILTIN_MEMSET
388 __builtin_memset (bootstrap_map.l_info, '\0', sizeof (bootstrap_map.l_info));
389 # else
390 for (size_t cnt = 0;
391 cnt < sizeof (bootstrap_map.l_info) / sizeof (bootstrap_map.l_info[0]);
392 ++cnt)
393 bootstrap_map.l_info[cnt] = 0;
394 # endif
395 # if USE___THREAD
396 bootstrap_map.l_tls_modid = 0;
397 # endif
398 #endif
400 /* Figure out the run-time load address of the dynamic linker itself. */
401 bootstrap_map.l_addr = elf_machine_load_address ();
403 /* Read our own dynamic section and fill in the info array. */
404 bootstrap_map.l_ld = (void *) bootstrap_map.l_addr + elf_machine_dynamic ();
405 elf_get_dynamic_info (&bootstrap_map, NULL);
407 #if NO_TLS_OFFSET != 0
408 bootstrap_map.l_tls_offset = NO_TLS_OFFSET;
409 #endif
411 /* Get the dynamic linker's own program header. First we need the ELF
412 file header. The `_begin' symbol created by the linker script points
413 to it. When we have something like GOTOFF relocs, we can use a plain
414 reference to find the runtime address. Without that, we have to rely
415 on the `l_addr' value, which is not the value we want when prelinked. */
416 #if USE___THREAD
417 dtv_t initdtv[3];
418 ElfW(Ehdr) *ehdr
419 # ifdef DONT_USE_BOOTSTRAP_MAP
420 = (ElfW(Ehdr) *) &_begin;
421 # else
422 # error This will not work with prelink.
423 = (ElfW(Ehdr) *) bootstrap_map.l_addr;
424 # endif
425 ElfW(Phdr) *phdr = (ElfW(Phdr) *) ((void *) ehdr + ehdr->e_phoff);
426 size_t cnt = ehdr->e_phnum; /* PT_TLS is usually the last phdr. */
427 while (cnt-- > 0)
428 if (phdr[cnt].p_type == PT_TLS)
430 void *tlsblock;
431 size_t max_align = MAX (TLS_INIT_TCB_ALIGN, phdr[cnt].p_align);
432 char *p;
434 bootstrap_map.l_tls_blocksize = phdr[cnt].p_memsz;
435 bootstrap_map.l_tls_align = phdr[cnt].p_align;
436 if (phdr[cnt].p_align == 0)
437 bootstrap_map.l_tls_firstbyte_offset = 0;
438 else
439 bootstrap_map.l_tls_firstbyte_offset = (phdr[cnt].p_vaddr
440 & (phdr[cnt].p_align - 1));
441 assert (bootstrap_map.l_tls_blocksize != 0);
442 bootstrap_map.l_tls_initimage_size = phdr[cnt].p_filesz;
443 bootstrap_map.l_tls_initimage = (void *) (bootstrap_map.l_addr
444 + phdr[cnt].p_vaddr);
446 /* We can now allocate the initial TLS block. This can happen
447 on the stack. We'll get the final memory later when we
448 know all about the various objects loaded at startup
449 time. */
450 # if TLS_TCB_AT_TP
451 tlsblock = alloca (roundup (bootstrap_map.l_tls_blocksize,
452 TLS_INIT_TCB_ALIGN)
453 + TLS_INIT_TCB_SIZE
454 + max_align);
455 # elif TLS_DTV_AT_TP
456 tlsblock = alloca (roundup (TLS_INIT_TCB_SIZE,
457 bootstrap_map.l_tls_align)
458 + bootstrap_map.l_tls_blocksize
459 + max_align);
460 # else
461 /* In case a model with a different layout for the TCB and DTV
462 is defined add another #elif here and in the following #ifs. */
463 # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
464 # endif
465 /* Align the TLS block. */
466 tlsblock = (void *) (((uintptr_t) tlsblock + max_align - 1)
467 & ~(max_align - 1));
469 /* Initialize the dtv. [0] is the length, [1] the generation
470 counter. */
471 initdtv[0].counter = 1;
472 initdtv[1].counter = 0;
474 /* Initialize the TLS block. */
475 # if TLS_TCB_AT_TP
476 initdtv[2].pointer = tlsblock;
477 # elif TLS_DTV_AT_TP
478 bootstrap_map.l_tls_offset = roundup (TLS_INIT_TCB_SIZE,
479 bootstrap_map.l_tls_align);
480 initdtv[2].pointer = (char *) tlsblock + bootstrap_map.l_tls_offset;
481 # else
482 # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
483 # endif
484 p = __mempcpy (initdtv[2].pointer, bootstrap_map.l_tls_initimage,
485 bootstrap_map.l_tls_initimage_size);
486 # ifdef HAVE_BUILTIN_MEMSET
487 __builtin_memset (p, '\0', (bootstrap_map.l_tls_blocksize
488 - bootstrap_map.l_tls_initimage_size));
489 # else
491 size_t remaining = (bootstrap_map.l_tls_blocksize
492 - bootstrap_map.l_tls_initimage_size);
493 while (remaining-- > 0)
494 *p++ = '\0';
496 # endif
498 /* Install the pointer to the dtv. */
500 /* Initialize the thread pointer. */
501 # if TLS_TCB_AT_TP
502 bootstrap_map.l_tls_offset
503 = roundup (bootstrap_map.l_tls_blocksize, TLS_INIT_TCB_ALIGN);
505 INSTALL_DTV ((char *) tlsblock + bootstrap_map.l_tls_offset,
506 initdtv);
508 const char *lossage = TLS_INIT_TP ((char *) tlsblock
509 + bootstrap_map.l_tls_offset, 0);
510 # elif TLS_DTV_AT_TP
511 INSTALL_DTV (tlsblock, initdtv);
512 const char *lossage = TLS_INIT_TP (tlsblock, 0);
513 # else
514 # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
515 # endif
516 if (__builtin_expect (lossage != NULL, 0))
517 _dl_fatal_printf ("cannot set up thread-local storage: %s\n",
518 lossage);
520 /* So far this is module number one. */
521 bootstrap_map.l_tls_modid = 1;
523 /* There can only be one PT_TLS entry. */
524 break;
526 #endif /* USE___THREAD */
528 #ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
529 ELF_MACHINE_BEFORE_RTLD_RELOC (bootstrap_map.l_info);
530 #endif
532 if (bootstrap_map.l_addr || ! bootstrap_map.l_info[VALIDX(DT_GNU_PRELINKED)])
534 /* Relocate ourselves so we can do normal function calls and
535 data access using the global offset table. */
537 ELF_DYNAMIC_RELOCATE (&bootstrap_map, 0, 0);
539 bootstrap_map.l_relocated = 1;
541 /* Please note that we don't allow profiling of this object and
542 therefore need not test whether we have to allocate the array
543 for the relocation results (as done in dl-reloc.c). */
545 /* Now life is sane; we can call functions and access global data.
546 Set up to use the operating system facilities, and find out from
547 the operating system's program loader where to find the program
548 header table in core. Put the rest of _dl_start into a separate
549 function, that way the compiler cannot put accesses to the GOT
550 before ELF_DYNAMIC_RELOCATE. */
552 #ifdef DONT_USE_BOOTSTRAP_MAP
553 ElfW(Addr) entry = _dl_start_final (arg);
554 #else
555 ElfW(Addr) entry = _dl_start_final (arg, &info);
556 #endif
558 #ifndef ELF_MACHINE_START_ADDRESS
559 # define ELF_MACHINE_START_ADDRESS(map, start) (start)
560 #endif
562 return ELF_MACHINE_START_ADDRESS (GL(dl_ns)[LM_ID_BASE]._ns_loaded, entry);
568 /* Now life is peachy; we can do all normal operations.
569 On to the real work. */
571 /* Some helper functions. */
573 /* Arguments to relocate_doit. */
574 struct relocate_args
576 struct link_map *l;
577 int lazy;
580 struct map_args
582 /* Argument to map_doit. */
583 char *str;
584 struct link_map *loader;
585 int is_preloaded;
586 int mode;
587 /* Return value of map_doit. */
588 struct link_map *map;
591 struct dlmopen_args
593 const char *fname;
594 struct link_map *map;
597 struct lookup_args
599 const char *name;
600 struct link_map *map;
601 void *result;
604 /* Arguments to version_check_doit. */
605 struct version_check_args
607 int doexit;
608 int dotrace;
611 static void
612 relocate_doit (void *a)
614 struct relocate_args *args = (struct relocate_args *) a;
616 _dl_relocate_object (args->l, args->l->l_scope, args->lazy, 0);
619 static void
620 map_doit (void *a)
622 struct map_args *args = (struct map_args *) a;
623 args->map = _dl_map_object (args->loader, args->str,
624 args->is_preloaded, lt_library, 0, args->mode,
625 LM_ID_BASE);
628 static void
629 dlmopen_doit (void *a)
631 struct dlmopen_args *args = (struct dlmopen_args *) a;
632 args->map = _dl_open (args->fname, RTLD_LAZY | __RTLD_DLOPEN | __RTLD_AUDIT,
633 dl_main, LM_ID_NEWLM, _dl_argc, INTUSE(_dl_argv),
634 __environ);
637 static void
638 lookup_doit (void *a)
640 struct lookup_args *args = (struct lookup_args *) a;
641 const ElfW(Sym) *ref = NULL;
642 args->result = NULL;
643 lookup_t l = _dl_lookup_symbol_x (args->name, args->map, &ref,
644 args->map->l_local_scope, NULL, 0,
645 DL_LOOKUP_RETURN_NEWEST, NULL);
646 if (ref != NULL)
647 args->result = DL_SYMBOL_ADDRESS (l, ref);
650 static void
651 version_check_doit (void *a)
653 struct version_check_args *args = (struct version_check_args *) a;
654 if (_dl_check_all_versions (GL(dl_ns)[LM_ID_BASE]._ns_loaded, 1,
655 args->dotrace) && args->doexit)
656 /* We cannot start the application. Abort now. */
657 _exit (1);
661 static inline struct link_map *
662 find_needed (const char *name)
664 struct r_scope_elem *scope = &GL(dl_ns)[LM_ID_BASE]._ns_loaded->l_searchlist;
665 unsigned int n = scope->r_nlist;
667 while (n-- > 0)
668 if (_dl_name_match_p (name, scope->r_list[n]))
669 return scope->r_list[n];
671 /* Should never happen. */
672 return NULL;
675 static int
676 match_version (const char *string, struct link_map *map)
678 const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
679 ElfW(Verdef) *def;
681 #define VERDEFTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERDEF))
682 if (map->l_info[VERDEFTAG] == NULL)
683 /* The file has no symbol versioning. */
684 return 0;
686 def = (ElfW(Verdef) *) ((char *) map->l_addr
687 + map->l_info[VERDEFTAG]->d_un.d_ptr);
688 while (1)
690 ElfW(Verdaux) *aux = (ElfW(Verdaux) *) ((char *) def + def->vd_aux);
692 /* Compare the version strings. */
693 if (strcmp (string, strtab + aux->vda_name) == 0)
694 /* Bingo! */
695 return 1;
697 /* If no more definitions we failed to find what we want. */
698 if (def->vd_next == 0)
699 break;
701 /* Next definition. */
702 def = (ElfW(Verdef) *) ((char *) def + def->vd_next);
705 return 0;
708 static bool tls_init_tp_called;
710 static void *
711 init_tls (void)
713 /* Number of elements in the static TLS block. */
714 GL(dl_tls_static_nelem) = GL(dl_tls_max_dtv_idx);
716 /* Do not do this twice. The audit interface might have required
717 the DTV interfaces to be set up early. */
718 if (GL(dl_initial_dtv) != NULL)
719 return NULL;
721 /* Allocate the array which contains the information about the
722 dtv slots. We allocate a few entries more than needed to
723 avoid the need for reallocation. */
724 size_t nelem = GL(dl_tls_max_dtv_idx) + 1 + TLS_SLOTINFO_SURPLUS;
726 /* Allocate. */
727 GL(dl_tls_dtv_slotinfo_list) = (struct dtv_slotinfo_list *)
728 calloc (sizeof (struct dtv_slotinfo_list)
729 + nelem * sizeof (struct dtv_slotinfo), 1);
730 /* No need to check the return value. If memory allocation failed
731 the program would have been terminated. */
733 struct dtv_slotinfo *slotinfo = GL(dl_tls_dtv_slotinfo_list)->slotinfo;
734 GL(dl_tls_dtv_slotinfo_list)->len = nelem;
735 GL(dl_tls_dtv_slotinfo_list)->next = NULL;
737 /* Fill in the information from the loaded modules. No namespace
738 but the base one can be filled at this time. */
739 assert (GL(dl_ns)[LM_ID_BASE + 1]._ns_loaded == NULL);
740 int i = 0;
741 for (struct link_map *l = GL(dl_ns)[LM_ID_BASE]._ns_loaded; l != NULL;
742 l = l->l_next)
743 if (l->l_tls_blocksize != 0)
745 /* This is a module with TLS data. Store the map reference.
746 The generation counter is zero. */
747 slotinfo[i].map = l;
748 /* slotinfo[i].gen = 0; */
749 ++i;
751 assert (i == GL(dl_tls_max_dtv_idx));
753 /* Compute the TLS offsets for the various blocks. */
754 _dl_determine_tlsoffset ();
756 /* Construct the static TLS block and the dtv for the initial
757 thread. For some platforms this will include allocating memory
758 for the thread descriptor. The memory for the TLS block will
759 never be freed. It should be allocated accordingly. The dtv
760 array can be changed if dynamic loading requires it. */
761 void *tcbp = _dl_allocate_tls_storage ();
762 if (tcbp == NULL)
763 _dl_fatal_printf ("\
764 cannot allocate TLS data structures for initial thread");
766 /* Store for detection of the special case by __tls_get_addr
767 so it knows not to pass this dtv to the normal realloc. */
768 GL(dl_initial_dtv) = GET_DTV (tcbp);
770 /* And finally install it for the main thread. If ld.so itself uses
771 TLS we know the thread pointer was initialized earlier. */
772 const char *lossage = TLS_INIT_TP (tcbp, USE___THREAD);
773 if (__builtin_expect (lossage != NULL, 0))
774 _dl_fatal_printf ("cannot set up thread-local storage: %s\n", lossage);
775 tls_init_tp_called = true;
777 return tcbp;
780 #ifdef _LIBC_REENTRANT
781 /* _dl_error_catch_tsd points to this for the single-threaded case.
782 It's reset by the thread library for multithreaded programs. */
783 void ** __attribute__ ((const))
784 _dl_initial_error_catch_tsd (void)
786 static void *data;
787 return &data;
789 #endif
792 static unsigned int
793 do_preload (char *fname, struct link_map *main_map, const char *where)
795 const char *objname;
796 const char *err_str = NULL;
797 struct map_args args;
798 bool malloced;
800 args.str = fname;
801 args.loader = main_map;
802 args.is_preloaded = 1;
803 args.mode = 0;
805 unsigned int old_nloaded = GL(dl_ns)[LM_ID_BASE]._ns_nloaded;
807 (void) _dl_catch_error (&objname, &err_str, &malloced, map_doit, &args);
808 if (__builtin_expect (err_str != NULL, 0))
810 _dl_error_printf ("\
811 ERROR: ld.so: object '%s' from %s cannot be preloaded: ignored.\n",
812 fname, where);
813 /* No need to call free, this is still before
814 the libc's malloc is used. */
816 else if (GL(dl_ns)[LM_ID_BASE]._ns_nloaded != old_nloaded)
817 /* It is no duplicate. */
818 return 1;
820 /* Nothing loaded. */
821 return 0;
824 #if defined SHARED && defined _LIBC_REENTRANT \
825 && defined __rtld_lock_default_lock_recursive
826 static void
827 rtld_lock_default_lock_recursive (void *lock)
829 __rtld_lock_default_lock_recursive (lock);
832 static void
833 rtld_lock_default_unlock_recursive (void *lock)
835 __rtld_lock_default_unlock_recursive (lock);
837 #endif
840 static void
841 security_init (void)
843 /* Set up the stack checker's canary. */
844 uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard (_dl_random);
845 #ifdef THREAD_SET_STACK_GUARD
846 THREAD_SET_STACK_GUARD (stack_chk_guard);
847 #else
848 __stack_chk_guard = stack_chk_guard;
849 #endif
851 /* Set up the pointer guard as well, if necessary. */
852 if (GLRO(dl_pointer_guard))
854 uintptr_t pointer_chk_guard = _dl_setup_pointer_guard (_dl_random,
855 stack_chk_guard);
856 #ifdef THREAD_SET_POINTER_GUARD
857 THREAD_SET_POINTER_GUARD (pointer_chk_guard);
858 #endif
859 __pointer_chk_guard_local = pointer_chk_guard;
862 /* We do not need the _dl_random value anymore. The less
863 information we leave behind, the better, so clear the
864 variable. */
865 _dl_random = NULL;
869 /* The library search path. */
870 static const char *library_path attribute_relro;
871 /* The list preloaded objects. */
872 static const char *preloadlist attribute_relro;
873 /* Nonzero if information about versions has to be printed. */
874 static int version_info attribute_relro;
876 static void
877 dl_main (const ElfW(Phdr) *phdr,
878 ElfW(Word) phnum,
879 ElfW(Addr) *user_entry)
881 const ElfW(Phdr) *ph;
882 enum mode mode;
883 struct link_map *main_map;
884 size_t file_size;
885 char *file;
886 bool has_interp = false;
887 unsigned int i;
888 bool prelinked = false;
889 bool rtld_is_main = false;
890 #ifndef HP_TIMING_NONAVAIL
891 hp_timing_t start;
892 hp_timing_t stop;
893 hp_timing_t diff;
894 #endif
895 void *tcbp = NULL;
897 #ifdef _LIBC_REENTRANT
898 /* Explicit initialization since the reloc would just be more work. */
899 GL(dl_error_catch_tsd) = &_dl_initial_error_catch_tsd;
900 #endif
902 GL(dl_init_static_tls) = &_dl_nothread_init_static_tls;
904 #if defined SHARED && defined _LIBC_REENTRANT \
905 && defined __rtld_lock_default_lock_recursive
906 GL(dl_rtld_lock_recursive) = rtld_lock_default_lock_recursive;
907 GL(dl_rtld_unlock_recursive) = rtld_lock_default_unlock_recursive;
908 #endif
910 /* The explicit initialization here is cheaper than processing the reloc
911 in the _rtld_local definition's initializer. */
912 GL(dl_make_stack_executable_hook) = &_dl_make_stack_executable;
914 /* Process the environment variable which control the behaviour. */
915 process_envvars (&mode);
917 #ifndef HAVE_INLINED_SYSCALLS
918 /* Set up a flag which tells we are just starting. */
919 INTUSE(_dl_starting_up) = 1;
920 #endif
922 if (*user_entry == (ElfW(Addr)) ENTRY_POINT)
924 /* Ho ho. We are not the program interpreter! We are the program
925 itself! This means someone ran ld.so as a command. Well, that
926 might be convenient to do sometimes. We support it by
927 interpreting the args like this:
929 ld.so PROGRAM ARGS...
931 The first argument is the name of a file containing an ELF
932 executable we will load and run with the following arguments.
933 To simplify life here, PROGRAM is searched for using the
934 normal rules for shared objects, rather than $PATH or anything
935 like that. We just load it and use its entry point; we don't
936 pay attention to its PT_INTERP command (we are the interpreter
937 ourselves). This is an easy way to test a new ld.so before
938 installing it. */
939 rtld_is_main = true;
941 /* Note the place where the dynamic linker actually came from. */
942 GL(dl_rtld_map).l_name = rtld_progname;
944 while (_dl_argc > 1)
945 if (! strcmp (INTUSE(_dl_argv)[1], "--list"))
947 mode = list;
948 GLRO(dl_lazy) = -1; /* This means do no dependency analysis. */
950 ++_dl_skip_args;
951 --_dl_argc;
952 ++INTUSE(_dl_argv);
954 else if (! strcmp (INTUSE(_dl_argv)[1], "--verify"))
956 mode = verify;
958 ++_dl_skip_args;
959 --_dl_argc;
960 ++INTUSE(_dl_argv);
962 else if (! strcmp (INTUSE(_dl_argv)[1], "--library-path")
963 && _dl_argc > 2)
965 library_path = INTUSE(_dl_argv)[2];
967 _dl_skip_args += 2;
968 _dl_argc -= 2;
969 INTUSE(_dl_argv) += 2;
971 else if (! strcmp (INTUSE(_dl_argv)[1], "--inhibit-rpath")
972 && _dl_argc > 2)
974 GLRO(dl_inhibit_rpath) = INTUSE(_dl_argv)[2];
976 _dl_skip_args += 2;
977 _dl_argc -= 2;
978 INTUSE(_dl_argv) += 2;
980 else if (! strcmp (INTUSE(_dl_argv)[1], "--audit") && _dl_argc > 2)
982 process_dl_audit (INTUSE(_dl_argv)[2]);
984 _dl_skip_args += 2;
985 _dl_argc -= 2;
986 INTUSE(_dl_argv) += 2;
988 else
989 break;
991 /* If we have no further argument the program was called incorrectly.
992 Grant the user some education. */
993 if (_dl_argc < 2)
994 _dl_fatal_printf ("\
995 Usage: ld.so [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\
996 You have invoked `ld.so', the helper program for shared library executables.\n\
997 This program usually lives in the file `/lib/ld.so', and special directives\n\
998 in executable files using ELF shared libraries tell the system's program\n\
999 loader to load the helper program from this file. This helper program loads\n\
1000 the shared libraries needed by the program executable, prepares the program\n\
1001 to run, and runs it. You may invoke this helper program directly from the\n\
1002 command line to load and run an ELF executable file; this is like executing\n\
1003 that file itself, but always uses this helper program from the file you\n\
1004 specified, instead of the helper program file specified in the executable\n\
1005 file you run. This is mostly of use for maintainers to test new versions\n\
1006 of this helper program; chances are you did not intend to run this program.\n\
1008 --list list all dependencies and how they are resolved\n\
1009 --verify verify that given object really is a dynamically linked\n\
1010 object we can handle\n\
1011 --library-path PATH use given PATH instead of content of the environment\n\
1012 variable LD_LIBRARY_PATH\n\
1013 --inhibit-rpath LIST ignore RUNPATH and RPATH information in object names\n\
1014 in LIST\n");
1016 ++_dl_skip_args;
1017 --_dl_argc;
1018 ++INTUSE(_dl_argv);
1020 /* The initialization of _dl_stack_flags done below assumes the
1021 executable's PT_GNU_STACK may have been honored by the kernel, and
1022 so a PT_GNU_STACK with PF_X set means the stack started out with
1023 execute permission. However, this is not really true if the
1024 dynamic linker is the executable the kernel loaded. For this
1025 case, we must reinitialize _dl_stack_flags to match the dynamic
1026 linker itself. If the dynamic linker was built with a
1027 PT_GNU_STACK, then the kernel may have loaded us with a
1028 nonexecutable stack that we will have to make executable when we
1029 load the program below unless it has a PT_GNU_STACK indicating
1030 nonexecutable stack is ok. */
1032 for (ph = phdr; ph < &phdr[phnum]; ++ph)
1033 if (ph->p_type == PT_GNU_STACK)
1035 GL(dl_stack_flags) = ph->p_flags;
1036 break;
1039 if (__builtin_expect (mode, normal) == verify)
1041 const char *objname;
1042 const char *err_str = NULL;
1043 struct map_args args;
1044 bool malloced;
1046 args.str = rtld_progname;
1047 args.loader = NULL;
1048 args.is_preloaded = 0;
1049 args.mode = __RTLD_OPENEXEC;
1050 (void) _dl_catch_error (&objname, &err_str, &malloced, map_doit,
1051 &args);
1052 if (__builtin_expect (err_str != NULL, 0))
1053 /* We don't free the returned string, the programs stops
1054 anyway. */
1055 _exit (EXIT_FAILURE);
1057 else
1059 HP_TIMING_NOW (start);
1060 _dl_map_object (NULL, rtld_progname, 0, lt_library, 0,
1061 __RTLD_OPENEXEC, LM_ID_BASE);
1062 HP_TIMING_NOW (stop);
1064 HP_TIMING_DIFF (load_time, start, stop);
1067 /* Now the map for the main executable is available. */
1068 main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
1070 phdr = main_map->l_phdr;
1071 phnum = main_map->l_phnum;
1072 /* We overwrite here a pointer to a malloc()ed string. But since
1073 the malloc() implementation used at this point is the dummy
1074 implementations which has no real free() function it does not
1075 makes sense to free the old string first. */
1076 main_map->l_name = (char *) "";
1077 *user_entry = main_map->l_entry;
1079 else
1081 /* Create a link_map for the executable itself.
1082 This will be what dlopen on "" returns. */
1083 main_map = _dl_new_object ((char *) "", "", lt_executable, NULL,
1084 __RTLD_OPENEXEC, LM_ID_BASE);
1085 assert (main_map != NULL);
1086 assert (main_map == GL(dl_ns)[LM_ID_BASE]._ns_loaded);
1087 main_map->l_phdr = phdr;
1088 main_map->l_phnum = phnum;
1089 main_map->l_entry = *user_entry;
1091 /* At this point we are in a bit of trouble. We would have to
1092 fill in the values for l_dev and l_ino. But in general we
1093 do not know where the file is. We also do not handle AT_EXECFD
1094 even if it would be passed up.
1096 We leave the values here defined to 0. This is normally no
1097 problem as the program code itself is normally no shared
1098 object and therefore cannot be loaded dynamically. Nothing
1099 prevent the use of dynamic binaries and in these situations
1100 we might get problems. We might not be able to find out
1101 whether the object is already loaded. But since there is no
1102 easy way out and because the dynamic binary must also not
1103 have an SONAME we ignore this program for now. If it becomes
1104 a problem we can force people using SONAMEs. */
1106 /* We delay initializing the path structure until we got the dynamic
1107 information for the program. */
1110 main_map->l_map_end = 0;
1111 main_map->l_text_end = 0;
1112 /* Perhaps the executable has no PT_LOAD header entries at all. */
1113 main_map->l_map_start = ~0;
1114 /* And it was opened directly. */
1115 ++main_map->l_direct_opencount;
1117 /* Scan the program header table for the dynamic section. */
1118 for (ph = phdr; ph < &phdr[phnum]; ++ph)
1119 switch (ph->p_type)
1121 case PT_PHDR:
1122 /* Find out the load address. */
1123 main_map->l_addr = (ElfW(Addr)) phdr - ph->p_vaddr;
1124 break;
1125 case PT_DYNAMIC:
1126 /* This tells us where to find the dynamic section,
1127 which tells us everything we need to do. */
1128 main_map->l_ld = (void *) main_map->l_addr + ph->p_vaddr;
1129 break;
1130 case PT_INTERP:
1131 /* This "interpreter segment" was used by the program loader to
1132 find the program interpreter, which is this program itself, the
1133 dynamic linker. We note what name finds us, so that a future
1134 dlopen call or DT_NEEDED entry, for something that wants to link
1135 against the dynamic linker as a shared library, will know that
1136 the shared object is already loaded. */
1137 _dl_rtld_libname.name = ((const char *) main_map->l_addr
1138 + ph->p_vaddr);
1139 /* _dl_rtld_libname.next = NULL; Already zero. */
1140 GL(dl_rtld_map).l_libname = &_dl_rtld_libname;
1142 /* Ordinarilly, we would get additional names for the loader from
1143 our DT_SONAME. This can't happen if we were actually linked as
1144 a static executable (detect this case when we have no DYNAMIC).
1145 If so, assume the filename component of the interpreter path to
1146 be our SONAME, and add it to our name list. */
1147 if (GL(dl_rtld_map).l_ld == NULL)
1149 const char *p = NULL;
1150 const char *cp = _dl_rtld_libname.name;
1152 /* Find the filename part of the path. */
1153 while (*cp != '\0')
1154 if (*cp++ == '/')
1155 p = cp;
1157 if (p != NULL)
1159 _dl_rtld_libname2.name = p;
1160 /* _dl_rtld_libname2.next = NULL; Already zero. */
1161 _dl_rtld_libname.next = &_dl_rtld_libname2;
1165 has_interp = true;
1166 break;
1167 case PT_LOAD:
1169 ElfW(Addr) mapstart;
1170 ElfW(Addr) allocend;
1172 /* Remember where the main program starts in memory. */
1173 mapstart = (main_map->l_addr
1174 + (ph->p_vaddr & ~(GLRO(dl_pagesize) - 1)));
1175 if (main_map->l_map_start > mapstart)
1176 main_map->l_map_start = mapstart;
1178 /* Also where it ends. */
1179 allocend = main_map->l_addr + ph->p_vaddr + ph->p_memsz;
1180 if (main_map->l_map_end < allocend)
1181 main_map->l_map_end = allocend;
1182 if ((ph->p_flags & PF_X) && allocend > main_map->l_text_end)
1183 main_map->l_text_end = allocend;
1185 break;
1187 case PT_TLS:
1188 if (ph->p_memsz > 0)
1190 /* Note that in the case the dynamic linker we duplicate work
1191 here since we read the PT_TLS entry already in
1192 _dl_start_final. But the result is repeatable so do not
1193 check for this special but unimportant case. */
1194 main_map->l_tls_blocksize = ph->p_memsz;
1195 main_map->l_tls_align = ph->p_align;
1196 if (ph->p_align == 0)
1197 main_map->l_tls_firstbyte_offset = 0;
1198 else
1199 main_map->l_tls_firstbyte_offset = (ph->p_vaddr
1200 & (ph->p_align - 1));
1201 main_map->l_tls_initimage_size = ph->p_filesz;
1202 main_map->l_tls_initimage = (void *) ph->p_vaddr;
1204 /* This image gets the ID one. */
1205 GL(dl_tls_max_dtv_idx) = main_map->l_tls_modid = 1;
1207 break;
1209 case PT_GNU_STACK:
1210 GL(dl_stack_flags) = ph->p_flags;
1211 break;
1213 case PT_GNU_RELRO:
1214 main_map->l_relro_addr = ph->p_vaddr;
1215 main_map->l_relro_size = ph->p_memsz;
1216 break;
1219 /* Adjust the address of the TLS initialization image in case
1220 the executable is actually an ET_DYN object. */
1221 if (main_map->l_tls_initimage != NULL)
1222 main_map->l_tls_initimage
1223 = (char *) main_map->l_tls_initimage + main_map->l_addr;
1224 if (! main_map->l_map_end)
1225 main_map->l_map_end = ~0;
1226 if (! main_map->l_text_end)
1227 main_map->l_text_end = ~0;
1228 if (! GL(dl_rtld_map).l_libname && GL(dl_rtld_map).l_name)
1230 /* We were invoked directly, so the program might not have a
1231 PT_INTERP. */
1232 _dl_rtld_libname.name = GL(dl_rtld_map).l_name;
1233 /* _dl_rtld_libname.next = NULL; Already zero. */
1234 GL(dl_rtld_map).l_libname = &_dl_rtld_libname;
1236 else
1237 assert (GL(dl_rtld_map).l_libname); /* How else did we get here? */
1239 /* If the current libname is different from the SONAME, add the
1240 latter as well. */
1241 if (GL(dl_rtld_map).l_info[DT_SONAME] != NULL
1242 && strcmp (GL(dl_rtld_map).l_libname->name,
1243 (const char *) D_PTR (&GL(dl_rtld_map), l_info[DT_STRTAB])
1244 + GL(dl_rtld_map).l_info[DT_SONAME]->d_un.d_val) != 0)
1246 static struct libname_list newname;
1247 newname.name = ((char *) D_PTR (&GL(dl_rtld_map), l_info[DT_STRTAB])
1248 + GL(dl_rtld_map).l_info[DT_SONAME]->d_un.d_ptr);
1249 newname.next = NULL;
1250 newname.dont_free = 1;
1252 assert (GL(dl_rtld_map).l_libname->next == NULL);
1253 GL(dl_rtld_map).l_libname->next = &newname;
1255 /* The ld.so must be relocated since otherwise loading audit modules
1256 will fail since they reuse the very same ld.so. */
1257 assert (GL(dl_rtld_map).l_relocated);
1259 if (! rtld_is_main)
1261 /* Extract the contents of the dynamic section for easy access. */
1262 elf_get_dynamic_info (main_map, NULL);
1263 /* Set up our cache of pointers into the hash table. */
1264 _dl_setup_hash (main_map);
1267 if (__builtin_expect (mode, normal) == verify)
1269 /* We were called just to verify that this is a dynamic
1270 executable using us as the program interpreter. Exit with an
1271 error if we were not able to load the binary or no interpreter
1272 is specified (i.e., this is no dynamically linked binary. */
1273 if (main_map->l_ld == NULL)
1274 _exit (1);
1276 /* We allow here some platform specific code. */
1277 #ifdef DISTINGUISH_LIB_VERSIONS
1278 DISTINGUISH_LIB_VERSIONS;
1279 #endif
1280 _exit (has_interp ? 0 : 2);
1283 struct link_map **first_preload = &GL(dl_rtld_map).l_next;
1284 #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
1285 /* Set up the data structures for the system-supplied DSO early,
1286 so they can influence _dl_init_paths. */
1287 if (GLRO(dl_sysinfo_dso) != NULL)
1289 /* Do an abridged version of the work _dl_map_object_from_fd would do
1290 to map in the object. It's already mapped and prelinked (and
1291 better be, since it's read-only and so we couldn't relocate it).
1292 We just want our data structures to describe it as if we had just
1293 mapped and relocated it normally. */
1294 struct link_map *l = _dl_new_object ((char *) "", "", lt_library, NULL,
1295 0, LM_ID_BASE);
1296 if (__builtin_expect (l != NULL, 1))
1298 static ElfW(Dyn) dyn_temp[DL_RO_DYN_TEMP_CNT] attribute_relro;
1300 l->l_phdr = ((const void *) GLRO(dl_sysinfo_dso)
1301 + GLRO(dl_sysinfo_dso)->e_phoff);
1302 l->l_phnum = GLRO(dl_sysinfo_dso)->e_phnum;
1303 for (uint_fast16_t i = 0; i < l->l_phnum; ++i)
1305 const ElfW(Phdr) *const ph = &l->l_phdr[i];
1306 if (ph->p_type == PT_DYNAMIC)
1308 l->l_ld = (void *) ph->p_vaddr;
1309 l->l_ldnum = ph->p_memsz / sizeof (ElfW(Dyn));
1311 else if (ph->p_type == PT_LOAD)
1313 if (! l->l_addr)
1314 l->l_addr = ph->p_vaddr;
1315 if (ph->p_vaddr + ph->p_memsz >= l->l_map_end)
1316 l->l_map_end = ph->p_vaddr + ph->p_memsz;
1317 if ((ph->p_flags & PF_X)
1318 && ph->p_vaddr + ph->p_memsz >= l->l_text_end)
1319 l->l_text_end = ph->p_vaddr + ph->p_memsz;
1321 else
1322 /* There must be no TLS segment. */
1323 assert (ph->p_type != PT_TLS);
1325 l->l_map_start = (ElfW(Addr)) GLRO(dl_sysinfo_dso);
1326 l->l_addr = l->l_map_start - l->l_addr;
1327 l->l_map_end += l->l_addr;
1328 l->l_text_end += l->l_addr;
1329 l->l_ld = (void *) ((ElfW(Addr)) l->l_ld + l->l_addr);
1330 elf_get_dynamic_info (l, dyn_temp);
1331 _dl_setup_hash (l);
1332 l->l_relocated = 1;
1334 /* Initialize l_local_scope to contain just this map. This allows
1335 the use of dl_lookup_symbol_x to resolve symbols within the vdso.
1336 So we create a single entry list pointing to l_real as its only
1337 element */
1338 l->l_local_scope[0]->r_nlist = 1;
1339 l->l_local_scope[0]->r_list = &l->l_real;
1341 /* Now that we have the info handy, use the DSO image's soname
1342 so this object can be looked up by name. Note that we do not
1343 set l_name here. That field gives the file name of the DSO,
1344 and this DSO is not associated with any file. */
1345 if (l->l_info[DT_SONAME] != NULL)
1347 /* Work around a kernel problem. The kernel cannot handle
1348 addresses in the vsyscall DSO pages in writev() calls. */
1349 const char *dsoname = ((char *) D_PTR (l, l_info[DT_STRTAB])
1350 + l->l_info[DT_SONAME]->d_un.d_val);
1351 size_t len = strlen (dsoname);
1352 char *copy = malloc (len);
1353 if (copy == NULL)
1354 _dl_fatal_printf ("out of memory\n");
1355 l->l_libname->name = memcpy (copy, dsoname, len);
1358 /* Rearrange the list so this DSO appears after rtld_map. */
1359 assert (l->l_next == NULL);
1360 assert (l->l_prev == main_map);
1361 GL(dl_rtld_map).l_next = l;
1362 l->l_prev = &GL(dl_rtld_map);
1363 first_preload = &l->l_next;
1365 /* We have a prelinked DSO preloaded by the system. */
1366 GLRO(dl_sysinfo_map) = l;
1367 # ifdef NEED_DL_SYSINFO
1368 if (GLRO(dl_sysinfo) == DL_SYSINFO_DEFAULT)
1369 GLRO(dl_sysinfo) = GLRO(dl_sysinfo_dso)->e_entry + l->l_addr;
1370 # endif
1373 #endif
1375 #ifdef DL_SYSDEP_OSCHECK
1376 DL_SYSDEP_OSCHECK (dl_fatal);
1377 #endif
1379 /* Initialize the data structures for the search paths for shared
1380 objects. */
1381 _dl_init_paths (library_path);
1383 /* Initialize _r_debug. */
1384 struct r_debug *r = _dl_debug_initialize (GL(dl_rtld_map).l_addr,
1385 LM_ID_BASE);
1386 r->r_state = RT_CONSISTENT;
1388 /* Put the link_map for ourselves on the chain so it can be found by
1389 name. Note that at this point the global chain of link maps contains
1390 exactly one element, which is pointed to by dl_loaded. */
1391 if (! GL(dl_rtld_map).l_name)
1392 /* If not invoked directly, the dynamic linker shared object file was
1393 found by the PT_INTERP name. */
1394 GL(dl_rtld_map).l_name = (char *) GL(dl_rtld_map).l_libname->name;
1395 GL(dl_rtld_map).l_type = lt_library;
1396 main_map->l_next = &GL(dl_rtld_map);
1397 GL(dl_rtld_map).l_prev = main_map;
1398 ++GL(dl_ns)[LM_ID_BASE]._ns_nloaded;
1399 ++GL(dl_load_adds);
1401 /* If LD_USE_LOAD_BIAS env variable has not been seen, default
1402 to not using bias for non-prelinked PIEs and libraries
1403 and using it for executables or prelinked PIEs or libraries. */
1404 if (GLRO(dl_use_load_bias) == (ElfW(Addr)) -2)
1405 GLRO(dl_use_load_bias) = main_map->l_addr == 0 ? -1 : 0;
1407 /* Set up the program header information for the dynamic linker
1408 itself. It is needed in the dl_iterate_phdr() callbacks. */
1409 ElfW(Ehdr) *rtld_ehdr = (ElfW(Ehdr) *) GL(dl_rtld_map).l_map_start;
1410 ElfW(Phdr) *rtld_phdr = (ElfW(Phdr) *) (GL(dl_rtld_map).l_map_start
1411 + rtld_ehdr->e_phoff);
1412 GL(dl_rtld_map).l_phdr = rtld_phdr;
1413 GL(dl_rtld_map).l_phnum = rtld_ehdr->e_phnum;
1416 /* PT_GNU_RELRO is usually the last phdr. */
1417 size_t cnt = rtld_ehdr->e_phnum;
1418 while (cnt-- > 0)
1419 if (rtld_phdr[cnt].p_type == PT_GNU_RELRO)
1421 GL(dl_rtld_map).l_relro_addr = rtld_phdr[cnt].p_vaddr;
1422 GL(dl_rtld_map).l_relro_size = rtld_phdr[cnt].p_memsz;
1423 break;
1426 /* Add the dynamic linker to the TLS list if it also uses TLS. */
1427 if (GL(dl_rtld_map).l_tls_blocksize != 0)
1428 /* Assign a module ID. Do this before loading any audit modules. */
1429 GL(dl_rtld_map).l_tls_modid = _dl_next_tls_modid ();
1431 /* If we have auditing DSOs to load, do it now. */
1432 if (__builtin_expect (audit_list != NULL, 0))
1434 /* Iterate over all entries in the list. The order is important. */
1435 struct audit_ifaces *last_audit = NULL;
1436 struct audit_list *al = audit_list->next;
1438 /* Since we start using the auditing DSOs right away we need to
1439 initialize the data structures now. */
1440 tcbp = init_tls ();
1442 /* Initialize security features. We need to do it this early
1443 since otherwise the constructors of the audit libraries will
1444 use different values (especially the pointer guard) and will
1445 fail later on. */
1446 security_init ();
1450 int tls_idx = GL(dl_tls_max_dtv_idx);
1452 /* Now it is time to determine the layout of the static TLS
1453 block and allocate it for the initial thread. Note that we
1454 always allocate the static block, we never defer it even if
1455 no DF_STATIC_TLS bit is set. The reason is that we know
1456 glibc will use the static model. */
1457 struct dlmopen_args dlmargs;
1458 dlmargs.fname = al->name;
1459 dlmargs.map = NULL;
1461 const char *objname;
1462 const char *err_str = NULL;
1463 bool malloced;
1464 (void) _dl_catch_error (&objname, &err_str, &malloced, dlmopen_doit,
1465 &dlmargs);
1466 if (__builtin_expect (err_str != NULL, 0))
1468 not_loaded:
1469 _dl_error_printf ("\
1470 ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
1471 al->name, err_str);
1472 if (malloced)
1473 free ((char *) err_str);
1475 else
1477 struct lookup_args largs;
1478 largs.name = "la_version";
1479 largs.map = dlmargs.map;
1481 /* Check whether the interface version matches. */
1482 (void) _dl_catch_error (&objname, &err_str, &malloced,
1483 lookup_doit, &largs);
1485 unsigned int (*laversion) (unsigned int);
1486 unsigned int lav;
1487 if (err_str == NULL
1488 && (laversion = largs.result) != NULL
1489 && (lav = laversion (LAV_CURRENT)) > 0
1490 && lav <= LAV_CURRENT)
1492 /* Allocate structure for the callback function pointers.
1493 This call can never fail. */
1494 union
1496 struct audit_ifaces ifaces;
1497 #define naudit_ifaces 8
1498 void (*fptr[naudit_ifaces]) (void);
1499 } *newp = malloc (sizeof (*newp));
1501 /* Names of the auditing interfaces. All in one
1502 long string. */
1503 static const char audit_iface_names[] =
1504 "la_activity\0"
1505 "la_objsearch\0"
1506 "la_objopen\0"
1507 "la_preinit\0"
1508 #if __ELF_NATIVE_CLASS == 32
1509 "la_symbind32\0"
1510 #elif __ELF_NATIVE_CLASS == 64
1511 "la_symbind64\0"
1512 #else
1513 # error "__ELF_NATIVE_CLASS must be defined"
1514 #endif
1515 #define STRING(s) __STRING (s)
1516 "la_" STRING (ARCH_LA_PLTENTER) "\0"
1517 "la_" STRING (ARCH_LA_PLTEXIT) "\0"
1518 "la_objclose\0";
1519 unsigned int cnt = 0;
1520 const char *cp = audit_iface_names;
1523 largs.name = cp;
1524 (void) _dl_catch_error (&objname, &err_str, &malloced,
1525 lookup_doit, &largs);
1527 /* Store the pointer. */
1528 if (err_str == NULL && largs.result != NULL)
1530 newp->fptr[cnt] = largs.result;
1532 /* The dynamic linker link map is statically
1533 allocated, initialize the data now. */
1534 GL(dl_rtld_map).l_audit[cnt].cookie
1535 = (intptr_t) &GL(dl_rtld_map);
1537 else
1538 newp->fptr[cnt] = NULL;
1539 ++cnt;
1541 cp = (char *) rawmemchr (cp, '\0') + 1;
1543 while (*cp != '\0');
1544 assert (cnt == naudit_ifaces);
1546 /* Now append the new auditing interface to the list. */
1547 newp->ifaces.next = NULL;
1548 if (last_audit == NULL)
1549 last_audit = GLRO(dl_audit) = &newp->ifaces;
1550 else
1551 last_audit = last_audit->next = &newp->ifaces;
1552 ++GLRO(dl_naudit);
1554 /* Mark the DSO as being used for auditing. */
1555 dlmargs.map->l_auditing = 1;
1557 else
1559 /* We cannot use the DSO, it does not have the
1560 appropriate interfaces or it expects something
1561 more recent. */
1562 #ifndef NDEBUG
1563 Lmid_t ns = dlmargs.map->l_ns;
1564 #endif
1565 _dl_close (dlmargs.map);
1567 /* Make sure the namespace has been cleared entirely. */
1568 assert (GL(dl_ns)[ns]._ns_loaded == NULL);
1569 assert (GL(dl_ns)[ns]._ns_nloaded == 0);
1571 GL(dl_tls_max_dtv_idx) = tls_idx;
1572 goto not_loaded;
1576 al = al->next;
1578 while (al != audit_list->next);
1580 /* If we have any auditing modules, announce that we already
1581 have two objects loaded. */
1582 if (__builtin_expect (GLRO(dl_naudit) > 0, 0))
1584 struct link_map *ls[2] = { main_map, &GL(dl_rtld_map) };
1586 for (unsigned int outer = 0; outer < 2; ++outer)
1588 struct audit_ifaces *afct = GLRO(dl_audit);
1589 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
1591 if (afct->objopen != NULL)
1593 ls[outer]->l_audit[cnt].bindflags
1594 = afct->objopen (ls[outer], LM_ID_BASE,
1595 &ls[outer]->l_audit[cnt].cookie);
1597 ls[outer]->l_audit_any_plt
1598 |= ls[outer]->l_audit[cnt].bindflags != 0;
1601 afct = afct->next;
1607 /* Set up debugging before the debugger is notified for the first time. */
1608 #ifdef ELF_MACHINE_DEBUG_SETUP
1609 /* Some machines (e.g. MIPS) don't use DT_DEBUG in this way. */
1610 ELF_MACHINE_DEBUG_SETUP (main_map, r);
1611 ELF_MACHINE_DEBUG_SETUP (&GL(dl_rtld_map), r);
1612 #else
1613 if (main_map->l_info[DT_DEBUG] != NULL)
1614 /* There is a DT_DEBUG entry in the dynamic section. Fill it in
1615 with the run-time address of the r_debug structure */
1616 main_map->l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r;
1618 /* Fill in the pointer in the dynamic linker's own dynamic section, in
1619 case you run gdb on the dynamic linker directly. */
1620 if (GL(dl_rtld_map).l_info[DT_DEBUG] != NULL)
1621 GL(dl_rtld_map).l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r;
1622 #endif
1624 /* We start adding objects. */
1625 r->r_state = RT_ADD;
1626 _dl_debug_state ();
1628 /* Auditing checkpoint: we are ready to signal that the initial map
1629 is being constructed. */
1630 if (__builtin_expect (GLRO(dl_naudit) > 0, 0))
1632 struct audit_ifaces *afct = GLRO(dl_audit);
1633 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
1635 if (afct->activity != NULL)
1636 afct->activity (&main_map->l_audit[cnt].cookie, LA_ACT_ADD);
1638 afct = afct->next;
1642 /* We have two ways to specify objects to preload: via environment
1643 variable and via the file /etc/ld.so.preload. The latter can also
1644 be used when security is enabled. */
1645 assert (*first_preload == NULL);
1646 struct link_map **preloads = NULL;
1647 unsigned int npreloads = 0;
1649 if (__builtin_expect (preloadlist != NULL, 0))
1651 /* The LD_PRELOAD environment variable gives list of libraries
1652 separated by white space or colons that are loaded before the
1653 executable's dependencies and prepended to the global scope
1654 list. If the binary is running setuid all elements
1655 containing a '/' are ignored since it is insecure. */
1656 char *list = strdupa (preloadlist);
1657 char *p;
1659 HP_TIMING_NOW (start);
1661 /* Prevent optimizing strsep. Speed is not important here. */
1662 while ((p = (strsep) (&list, " :")) != NULL)
1663 if (p[0] != '\0'
1664 && (__builtin_expect (! INTUSE(__libc_enable_secure), 1)
1665 || strchr (p, '/') == NULL))
1666 npreloads += do_preload (p, main_map, "LD_PRELOAD");
1668 HP_TIMING_NOW (stop);
1669 HP_TIMING_DIFF (diff, start, stop);
1670 HP_TIMING_ACCUM_NT (load_time, diff);
1673 /* There usually is no ld.so.preload file, it should only be used
1674 for emergencies and testing. So the open call etc should usually
1675 fail. Using access() on a non-existing file is faster than using
1676 open(). So we do this first. If it succeeds we do almost twice
1677 the work but this does not matter, since it is not for production
1678 use. */
1679 static const char preload_file[] = "/etc/ld.so.preload";
1680 if (__builtin_expect (__access (preload_file, R_OK) == 0, 0))
1682 /* Read the contents of the file. */
1683 file = _dl_sysdep_read_whole_file (preload_file, &file_size,
1684 PROT_READ | PROT_WRITE);
1685 if (__builtin_expect (file != MAP_FAILED, 0))
1687 /* Parse the file. It contains names of libraries to be loaded,
1688 separated by white spaces or `:'. It may also contain
1689 comments introduced by `#'. */
1690 char *problem;
1691 char *runp;
1692 size_t rest;
1694 /* Eliminate comments. */
1695 runp = file;
1696 rest = file_size;
1697 while (rest > 0)
1699 char *comment = memchr (runp, '#', rest);
1700 if (comment == NULL)
1701 break;
1703 rest -= comment - runp;
1705 *comment = ' ';
1706 while (--rest > 0 && *++comment != '\n');
1709 /* We have one problematic case: if we have a name at the end of
1710 the file without a trailing terminating characters, we cannot
1711 place the \0. Handle the case separately. */
1712 if (file[file_size - 1] != ' ' && file[file_size - 1] != '\t'
1713 && file[file_size - 1] != '\n' && file[file_size - 1] != ':')
1715 problem = &file[file_size];
1716 while (problem > file && problem[-1] != ' '
1717 && problem[-1] != '\t'
1718 && problem[-1] != '\n' && problem[-1] != ':')
1719 --problem;
1721 if (problem > file)
1722 problem[-1] = '\0';
1724 else
1726 problem = NULL;
1727 file[file_size - 1] = '\0';
1730 HP_TIMING_NOW (start);
1732 if (file != problem)
1734 char *p;
1735 runp = file;
1736 while ((p = strsep (&runp, ": \t\n")) != NULL)
1737 if (p[0] != '\0')
1738 npreloads += do_preload (p, main_map, preload_file);
1741 if (problem != NULL)
1743 char *p = strndupa (problem, file_size - (problem - file));
1745 npreloads += do_preload (p, main_map, preload_file);
1748 HP_TIMING_NOW (stop);
1749 HP_TIMING_DIFF (diff, start, stop);
1750 HP_TIMING_ACCUM_NT (load_time, diff);
1752 /* We don't need the file anymore. */
1753 __munmap (file, file_size);
1757 if (__builtin_expect (*first_preload != NULL, 0))
1759 /* Set up PRELOADS with a vector of the preloaded libraries. */
1760 struct link_map *l = *first_preload;
1761 preloads = __alloca (npreloads * sizeof preloads[0]);
1762 i = 0;
1765 preloads[i++] = l;
1766 l = l->l_next;
1767 } while (l);
1768 assert (i == npreloads);
1771 /* Load all the libraries specified by DT_NEEDED entries. If LD_PRELOAD
1772 specified some libraries to load, these are inserted before the actual
1773 dependencies in the executable's searchlist for symbol resolution. */
1774 HP_TIMING_NOW (start);
1775 _dl_map_object_deps (main_map, preloads, npreloads, mode == trace, 0);
1776 HP_TIMING_NOW (stop);
1777 HP_TIMING_DIFF (diff, start, stop);
1778 HP_TIMING_ACCUM_NT (load_time, diff);
1780 /* Mark all objects as being in the global scope. */
1781 for (i = main_map->l_searchlist.r_nlist; i > 0; )
1782 main_map->l_searchlist.r_list[--i]->l_global = 1;
1784 #ifndef MAP_ANON
1785 /* We are done mapping things, so close the zero-fill descriptor. */
1786 __close (_dl_zerofd);
1787 _dl_zerofd = -1;
1788 #endif
1790 /* Remove _dl_rtld_map from the chain. */
1791 GL(dl_rtld_map).l_prev->l_next = GL(dl_rtld_map).l_next;
1792 if (GL(dl_rtld_map).l_next != NULL)
1793 GL(dl_rtld_map).l_next->l_prev = GL(dl_rtld_map).l_prev;
1795 for (i = 1; i < main_map->l_searchlist.r_nlist; ++i)
1796 if (main_map->l_searchlist.r_list[i] == &GL(dl_rtld_map))
1797 break;
1799 bool rtld_multiple_ref = false;
1800 if (__builtin_expect (i < main_map->l_searchlist.r_nlist, 1))
1802 /* Some DT_NEEDED entry referred to the interpreter object itself, so
1803 put it back in the list of visible objects. We insert it into the
1804 chain in symbol search order because gdb uses the chain's order as
1805 its symbol search order. */
1806 rtld_multiple_ref = true;
1808 GL(dl_rtld_map).l_prev = main_map->l_searchlist.r_list[i - 1];
1809 if (__builtin_expect (mode, normal) == normal)
1811 GL(dl_rtld_map).l_next = (i + 1 < main_map->l_searchlist.r_nlist
1812 ? main_map->l_searchlist.r_list[i + 1]
1813 : NULL);
1814 #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
1815 if (GLRO(dl_sysinfo_map) != NULL
1816 && GL(dl_rtld_map).l_prev->l_next == GLRO(dl_sysinfo_map)
1817 && GL(dl_rtld_map).l_next != GLRO(dl_sysinfo_map))
1818 GL(dl_rtld_map).l_prev = GLRO(dl_sysinfo_map);
1819 #endif
1821 else
1822 /* In trace mode there might be an invisible object (which we
1823 could not find) after the previous one in the search list.
1824 In this case it doesn't matter much where we put the
1825 interpreter object, so we just initialize the list pointer so
1826 that the assertion below holds. */
1827 GL(dl_rtld_map).l_next = GL(dl_rtld_map).l_prev->l_next;
1829 assert (GL(dl_rtld_map).l_prev->l_next == GL(dl_rtld_map).l_next);
1830 GL(dl_rtld_map).l_prev->l_next = &GL(dl_rtld_map);
1831 if (GL(dl_rtld_map).l_next != NULL)
1833 assert (GL(dl_rtld_map).l_next->l_prev == GL(dl_rtld_map).l_prev);
1834 GL(dl_rtld_map).l_next->l_prev = &GL(dl_rtld_map);
1838 /* Now let us see whether all libraries are available in the
1839 versions we need. */
1841 struct version_check_args args;
1842 args.doexit = mode == normal;
1843 args.dotrace = mode == trace;
1844 _dl_receive_error (print_missing_version, version_check_doit, &args);
1847 /* We do not initialize any of the TLS functionality unless any of the
1848 initial modules uses TLS. This makes dynamic loading of modules with
1849 TLS impossible, but to support it requires either eagerly doing setup
1850 now or lazily doing it later. Doing it now makes us incompatible with
1851 an old kernel that can't perform TLS_INIT_TP, even if no TLS is ever
1852 used. Trying to do it lazily is too hairy to try when there could be
1853 multiple threads (from a non-TLS-using libpthread). */
1854 bool was_tls_init_tp_called = tls_init_tp_called;
1855 if (tcbp == NULL)
1856 tcbp = init_tls ();
1858 if (__builtin_expect (audit_list == NULL, 1))
1859 /* Initialize security features. But only if we have not done it
1860 earlier. */
1861 security_init ();
1863 if (__builtin_expect (mode, normal) != normal)
1865 /* We were run just to list the shared libraries. It is
1866 important that we do this before real relocation, because the
1867 functions we call below for output may no longer work properly
1868 after relocation. */
1869 struct link_map *l;
1871 if (GLRO(dl_debug_mask) & DL_DEBUG_PRELINK)
1873 struct r_scope_elem *scope = &main_map->l_searchlist;
1875 for (i = 0; i < scope->r_nlist; i++)
1877 l = scope->r_list [i];
1878 if (l->l_faked)
1880 _dl_printf ("\t%s => not found\n", l->l_libname->name);
1881 continue;
1883 if (_dl_name_match_p (GLRO(dl_trace_prelink), l))
1884 GLRO(dl_trace_prelink_map) = l;
1885 _dl_printf ("\t%s => %s (0x%0*Zx, 0x%0*Zx)",
1886 l->l_libname->name[0] ? l->l_libname->name
1887 : rtld_progname ?: "<main program>",
1888 l->l_name[0] ? l->l_name
1889 : rtld_progname ?: "<main program>",
1890 (int) sizeof l->l_map_start * 2,
1891 (size_t) l->l_map_start,
1892 (int) sizeof l->l_addr * 2,
1893 (size_t) l->l_addr);
1895 if (l->l_tls_modid)
1896 _dl_printf (" TLS(0x%Zx, 0x%0*Zx)\n", l->l_tls_modid,
1897 (int) sizeof l->l_tls_offset * 2,
1898 (size_t) l->l_tls_offset);
1899 else
1900 _dl_printf ("\n");
1903 else if (GLRO(dl_debug_mask) & DL_DEBUG_UNUSED)
1905 /* Look through the dependencies of the main executable
1906 and determine which of them is not actually
1907 required. */
1908 struct link_map *l = main_map;
1910 /* Relocate the main executable. */
1911 struct relocate_args args = { .l = l, .lazy = GLRO(dl_lazy) };
1912 _dl_receive_error (print_unresolved, relocate_doit, &args);
1914 /* This loop depends on the dependencies of the executable to
1915 correspond in number and order to the DT_NEEDED entries. */
1916 ElfW(Dyn) *dyn = main_map->l_ld;
1917 bool first = true;
1918 while (dyn->d_tag != DT_NULL)
1920 if (dyn->d_tag == DT_NEEDED)
1922 l = l->l_next;
1924 if (!l->l_used)
1926 if (first)
1928 _dl_printf ("Unused direct dependencies:\n");
1929 first = false;
1932 _dl_printf ("\t%s\n", l->l_name);
1936 ++dyn;
1939 _exit (first != true);
1941 else if (! main_map->l_info[DT_NEEDED])
1942 _dl_printf ("\tstatically linked\n");
1943 else
1945 for (l = main_map->l_next; l; l = l->l_next)
1946 if (l->l_faked)
1947 /* The library was not found. */
1948 _dl_printf ("\t%s => not found\n", l->l_libname->name);
1949 else if (strcmp (l->l_libname->name, l->l_name) == 0)
1950 _dl_printf ("\t%s (0x%0*Zx)\n", l->l_libname->name,
1951 (int) sizeof l->l_map_start * 2,
1952 (size_t) l->l_map_start);
1953 else
1954 _dl_printf ("\t%s => %s (0x%0*Zx)\n", l->l_libname->name,
1955 l->l_name, (int) sizeof l->l_map_start * 2,
1956 (size_t) l->l_map_start);
1959 if (__builtin_expect (mode, trace) != trace)
1960 for (i = 1; i < (unsigned int) _dl_argc; ++i)
1962 const ElfW(Sym) *ref = NULL;
1963 ElfW(Addr) loadbase;
1964 lookup_t result;
1966 result = _dl_lookup_symbol_x (INTUSE(_dl_argv)[i], main_map,
1967 &ref, main_map->l_scope,
1968 NULL, ELF_RTYPE_CLASS_PLT,
1969 DL_LOOKUP_ADD_DEPENDENCY, NULL);
1971 loadbase = LOOKUP_VALUE_ADDRESS (result);
1973 _dl_printf ("%s found at 0x%0*Zd in object at 0x%0*Zd\n",
1974 INTUSE(_dl_argv)[i],
1975 (int) sizeof ref->st_value * 2,
1976 (size_t) ref->st_value,
1977 (int) sizeof loadbase * 2, (size_t) loadbase);
1979 else
1981 /* If LD_WARN is set, warn about undefined symbols. */
1982 if (GLRO(dl_lazy) >= 0 && GLRO(dl_verbose))
1984 /* We have to do symbol dependency testing. */
1985 struct relocate_args args;
1986 struct link_map *l;
1988 args.lazy = GLRO(dl_lazy);
1990 l = main_map;
1991 while (l->l_next != NULL)
1992 l = l->l_next;
1995 if (l != &GL(dl_rtld_map) && ! l->l_faked)
1997 args.l = l;
1998 _dl_receive_error (print_unresolved, relocate_doit,
1999 &args);
2001 l = l->l_prev;
2003 while (l != NULL);
2005 if ((GLRO(dl_debug_mask) & DL_DEBUG_PRELINK)
2006 && rtld_multiple_ref)
2008 /* Mark the link map as not yet relocated again. */
2009 GL(dl_rtld_map).l_relocated = 0;
2010 _dl_relocate_object (&GL(dl_rtld_map),
2011 main_map->l_scope, 0, 0);
2014 #define VERNEEDTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERNEED))
2015 if (version_info)
2017 /* Print more information. This means here, print information
2018 about the versions needed. */
2019 int first = 1;
2020 struct link_map *map;
2022 for (map = main_map; map != NULL; map = map->l_next)
2024 const char *strtab;
2025 ElfW(Dyn) *dyn = map->l_info[VERNEEDTAG];
2026 ElfW(Verneed) *ent;
2028 if (dyn == NULL)
2029 continue;
2031 strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
2032 ent = (ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr);
2034 if (first)
2036 _dl_printf ("\n\tVersion information:\n");
2037 first = 0;
2040 _dl_printf ("\t%s:\n",
2041 map->l_name[0] ? map->l_name : rtld_progname);
2043 while (1)
2045 ElfW(Vernaux) *aux;
2046 struct link_map *needed;
2048 needed = find_needed (strtab + ent->vn_file);
2049 aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux);
2051 while (1)
2053 const char *fname = NULL;
2055 if (needed != NULL
2056 && match_version (strtab + aux->vna_name,
2057 needed))
2058 fname = needed->l_name;
2060 _dl_printf ("\t\t%s (%s) %s=> %s\n",
2061 strtab + ent->vn_file,
2062 strtab + aux->vna_name,
2063 aux->vna_flags & VER_FLG_WEAK
2064 ? "[WEAK] " : "",
2065 fname ?: "not found");
2067 if (aux->vna_next == 0)
2068 /* No more symbols. */
2069 break;
2071 /* Next symbol. */
2072 aux = (ElfW(Vernaux) *) ((char *) aux
2073 + aux->vna_next);
2076 if (ent->vn_next == 0)
2077 /* No more dependencies. */
2078 break;
2080 /* Next dependency. */
2081 ent = (ElfW(Verneed) *) ((char *) ent + ent->vn_next);
2087 _exit (0);
2090 if (main_map->l_info[ADDRIDX (DT_GNU_LIBLIST)]
2091 && ! __builtin_expect (GLRO(dl_profile) != NULL, 0)
2092 && ! __builtin_expect (GLRO(dl_dynamic_weak), 0))
2094 ElfW(Lib) *liblist, *liblistend;
2095 struct link_map **r_list, **r_listend, *l;
2096 const char *strtab = (const void *) D_PTR (main_map, l_info[DT_STRTAB]);
2098 assert (main_map->l_info[VALIDX (DT_GNU_LIBLISTSZ)] != NULL);
2099 liblist = (ElfW(Lib) *)
2100 main_map->l_info[ADDRIDX (DT_GNU_LIBLIST)]->d_un.d_ptr;
2101 liblistend = (ElfW(Lib) *)
2102 ((char *) liblist +
2103 main_map->l_info[VALIDX (DT_GNU_LIBLISTSZ)]->d_un.d_val);
2104 r_list = main_map->l_searchlist.r_list;
2105 r_listend = r_list + main_map->l_searchlist.r_nlist;
2107 for (; r_list < r_listend && liblist < liblistend; r_list++)
2109 l = *r_list;
2111 if (l == main_map)
2112 continue;
2114 /* If the library is not mapped where it should, fail. */
2115 if (l->l_addr)
2116 break;
2118 /* Next, check if checksum matches. */
2119 if (l->l_info [VALIDX(DT_CHECKSUM)] == NULL
2120 || l->l_info [VALIDX(DT_CHECKSUM)]->d_un.d_val
2121 != liblist->l_checksum)
2122 break;
2124 if (l->l_info [VALIDX(DT_GNU_PRELINKED)] == NULL
2125 || l->l_info [VALIDX(DT_GNU_PRELINKED)]->d_un.d_val
2126 != liblist->l_time_stamp)
2127 break;
2129 if (! _dl_name_match_p (strtab + liblist->l_name, l))
2130 break;
2132 ++liblist;
2136 if (r_list == r_listend && liblist == liblistend)
2137 prelinked = true;
2139 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_LIBS, 0))
2140 _dl_debug_printf ("\nprelink checking: %s\n",
2141 prelinked ? "ok" : "failed");
2145 /* Now set up the variable which helps the assembler startup code. */
2146 GL(dl_ns)[LM_ID_BASE]._ns_main_searchlist = &main_map->l_searchlist;
2148 /* Save the information about the original global scope list since
2149 we need it in the memory handling later. */
2150 GLRO(dl_initial_searchlist) = *GL(dl_ns)[LM_ID_BASE]._ns_main_searchlist;
2152 if (prelinked)
2154 if (main_map->l_info [ADDRIDX (DT_GNU_CONFLICT)] != NULL)
2156 ElfW(Rela) *conflict, *conflictend;
2157 #ifndef HP_TIMING_NONAVAIL
2158 hp_timing_t start;
2159 hp_timing_t stop;
2160 #endif
2162 HP_TIMING_NOW (start);
2163 assert (main_map->l_info [VALIDX (DT_GNU_CONFLICTSZ)] != NULL);
2164 conflict = (ElfW(Rela) *)
2165 main_map->l_info [ADDRIDX (DT_GNU_CONFLICT)]->d_un.d_ptr;
2166 conflictend = (ElfW(Rela) *)
2167 ((char *) conflict
2168 + main_map->l_info [VALIDX (DT_GNU_CONFLICTSZ)]->d_un.d_val);
2169 _dl_resolve_conflicts (main_map, conflict, conflictend);
2170 HP_TIMING_NOW (stop);
2171 HP_TIMING_DIFF (relocate_time, start, stop);
2175 /* Mark all the objects so we know they have been already relocated. */
2176 for (struct link_map *l = main_map; l != NULL; l = l->l_next)
2178 l->l_relocated = 1;
2179 if (l->l_relro_size)
2180 _dl_protect_relro (l);
2182 /* Add object to slot information data if necessasy. */
2183 if (l->l_tls_blocksize != 0 && tls_init_tp_called)
2184 _dl_add_to_slotinfo (l);
2187 _dl_sysdep_start_cleanup ();
2189 else
2191 /* Now we have all the objects loaded. Relocate them all except for
2192 the dynamic linker itself. We do this in reverse order so that copy
2193 relocs of earlier objects overwrite the data written by later
2194 objects. We do not re-relocate the dynamic linker itself in this
2195 loop because that could result in the GOT entries for functions we
2196 call being changed, and that would break us. It is safe to relocate
2197 the dynamic linker out of order because it has no copy relocs (we
2198 know that because it is self-contained). */
2200 int consider_profiling = GLRO(dl_profile) != NULL;
2201 #ifndef HP_TIMING_NONAVAIL
2202 hp_timing_t start;
2203 hp_timing_t stop;
2204 #endif
2206 /* If we are profiling we also must do lazy reloaction. */
2207 GLRO(dl_lazy) |= consider_profiling;
2209 struct link_map *l = main_map;
2210 while (l->l_next)
2211 l = l->l_next;
2213 HP_TIMING_NOW (start);
2216 /* While we are at it, help the memory handling a bit. We have to
2217 mark some data structures as allocated with the fake malloc()
2218 implementation in ld.so. */
2219 struct libname_list *lnp = l->l_libname->next;
2221 while (__builtin_expect (lnp != NULL, 0))
2223 lnp->dont_free = 1;
2224 lnp = lnp->next;
2227 if (l != &GL(dl_rtld_map))
2228 _dl_relocate_object (l, l->l_scope, GLRO(dl_lazy),
2229 consider_profiling);
2231 /* Add object to slot information data if necessasy. */
2232 if (l->l_tls_blocksize != 0 && tls_init_tp_called)
2233 _dl_add_to_slotinfo (l);
2235 l = l->l_prev;
2237 while (l);
2238 HP_TIMING_NOW (stop);
2240 HP_TIMING_DIFF (relocate_time, start, stop);
2242 /* Do any necessary cleanups for the startup OS interface code.
2243 We do these now so that no calls are made after rtld re-relocation
2244 which might be resolved to different functions than we expect.
2245 We cannot do this before relocating the other objects because
2246 _dl_relocate_object might need to call `mprotect' for DT_TEXTREL. */
2247 _dl_sysdep_start_cleanup ();
2249 /* Now enable profiling if needed. Like the previous call,
2250 this has to go here because the calls it makes should use the
2251 rtld versions of the functions (particularly calloc()), but it
2252 needs to have _dl_profile_map set up by the relocator. */
2253 if (__builtin_expect (GL(dl_profile_map) != NULL, 0))
2254 /* We must prepare the profiling. */
2255 _dl_start_profile ();
2258 #ifndef NONTLS_INIT_TP
2259 # define NONTLS_INIT_TP do { } while (0)
2260 #endif
2262 if (!was_tls_init_tp_called && GL(dl_tls_max_dtv_idx) > 0)
2263 ++GL(dl_tls_generation);
2265 /* Now that we have completed relocation, the initializer data
2266 for the TLS blocks has its final values and we can copy them
2267 into the main thread's TLS area, which we allocated above. */
2268 _dl_allocate_tls_init (tcbp);
2270 /* And finally install it for the main thread. If ld.so itself uses
2271 TLS we know the thread pointer was initialized earlier. */
2272 if (! tls_init_tp_called)
2274 const char *lossage = TLS_INIT_TP (tcbp, USE___THREAD);
2275 if (__builtin_expect (lossage != NULL, 0))
2276 _dl_fatal_printf ("cannot set up thread-local storage: %s\n",
2277 lossage);
2280 if (! prelinked && rtld_multiple_ref)
2282 /* There was an explicit ref to the dynamic linker as a shared lib.
2283 Re-relocate ourselves with user-controlled symbol definitions.
2285 We must do this after TLS initialization in case after this
2286 re-relocation, we might call a user-supplied function
2287 (e.g. calloc from _dl_relocate_object) that uses TLS data. */
2289 #ifndef HP_TIMING_NONAVAIL
2290 hp_timing_t start;
2291 hp_timing_t stop;
2292 hp_timing_t add;
2293 #endif
2295 HP_TIMING_NOW (start);
2296 /* Mark the link map as not yet relocated again. */
2297 GL(dl_rtld_map).l_relocated = 0;
2298 _dl_relocate_object (&GL(dl_rtld_map), main_map->l_scope, 0, 0);
2299 HP_TIMING_NOW (stop);
2300 HP_TIMING_DIFF (add, start, stop);
2301 HP_TIMING_ACCUM_NT (relocate_time, add);
2304 #ifdef SHARED
2305 /* Auditing checkpoint: we have added all objects. */
2306 if (__builtin_expect (GLRO(dl_naudit) > 0, 0))
2308 struct link_map *head = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
2309 /* Do not call the functions for any auditing object. */
2310 if (head->l_auditing == 0)
2312 struct audit_ifaces *afct = GLRO(dl_audit);
2313 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
2315 if (afct->activity != NULL)
2316 afct->activity (&head->l_audit[cnt].cookie, LA_ACT_CONSISTENT);
2318 afct = afct->next;
2322 #endif
2324 /* Notify the debugger all new objects are now ready to go. We must re-get
2325 the address since by now the variable might be in another object. */
2326 r = _dl_debug_initialize (0, LM_ID_BASE);
2327 r->r_state = RT_CONSISTENT;
2328 _dl_debug_state ();
2330 #ifndef MAP_COPY
2331 /* We must munmap() the cache file. */
2332 _dl_unload_cache ();
2333 #endif
2335 /* Once we return, _dl_sysdep_start will invoke
2336 the DT_INIT functions and then *USER_ENTRY. */
2339 /* This is a little helper function for resolving symbols while
2340 tracing the binary. */
2341 static void
2342 print_unresolved (int errcode __attribute__ ((unused)), const char *objname,
2343 const char *errstring)
2345 if (objname[0] == '\0')
2346 objname = rtld_progname ?: "<main program>";
2347 _dl_error_printf ("%s (%s)\n", errstring, objname);
2350 /* This is a little helper function for resolving symbols while
2351 tracing the binary. */
2352 static void
2353 print_missing_version (int errcode __attribute__ ((unused)),
2354 const char *objname, const char *errstring)
2356 _dl_error_printf ("%s: %s: %s\n", rtld_progname ?: "<program name unknown>",
2357 objname, errstring);
2360 /* Nonzero if any of the debugging options is enabled. */
2361 static int any_debug attribute_relro;
2363 /* Process the string given as the parameter which explains which debugging
2364 options are enabled. */
2365 static void
2366 process_dl_debug (const char *dl_debug)
2368 /* When adding new entries make sure that the maximal length of a name
2369 is correctly handled in the LD_DEBUG_HELP code below. */
2370 static const struct
2372 unsigned char len;
2373 const char name[10];
2374 const char helptext[41];
2375 unsigned short int mask;
2376 } debopts[] =
2378 #define LEN_AND_STR(str) sizeof (str) - 1, str
2379 { LEN_AND_STR ("libs"), "display library search paths",
2380 DL_DEBUG_LIBS | DL_DEBUG_IMPCALLS },
2381 { LEN_AND_STR ("reloc"), "display relocation processing",
2382 DL_DEBUG_RELOC | DL_DEBUG_IMPCALLS },
2383 { LEN_AND_STR ("files"), "display progress for input file",
2384 DL_DEBUG_FILES | DL_DEBUG_IMPCALLS },
2385 { LEN_AND_STR ("symbols"), "display symbol table processing",
2386 DL_DEBUG_SYMBOLS | DL_DEBUG_IMPCALLS },
2387 { LEN_AND_STR ("bindings"), "display information about symbol binding",
2388 DL_DEBUG_BINDINGS | DL_DEBUG_IMPCALLS },
2389 { LEN_AND_STR ("versions"), "display version dependencies",
2390 DL_DEBUG_VERSIONS | DL_DEBUG_IMPCALLS },
2391 { LEN_AND_STR ("all"), "all previous options combined",
2392 DL_DEBUG_LIBS | DL_DEBUG_RELOC | DL_DEBUG_FILES | DL_DEBUG_SYMBOLS
2393 | DL_DEBUG_BINDINGS | DL_DEBUG_VERSIONS | DL_DEBUG_IMPCALLS },
2394 { LEN_AND_STR ("statistics"), "display relocation statistics",
2395 DL_DEBUG_STATISTICS },
2396 { LEN_AND_STR ("unused"), "determined unused DSOs",
2397 DL_DEBUG_UNUSED },
2398 { LEN_AND_STR ("help"), "display this help message and exit",
2399 DL_DEBUG_HELP },
2401 #define ndebopts (sizeof (debopts) / sizeof (debopts[0]))
2403 /* Skip separating white spaces and commas. */
2404 while (*dl_debug != '\0')
2406 if (*dl_debug != ' ' && *dl_debug != ',' && *dl_debug != ':')
2408 size_t cnt;
2409 size_t len = 1;
2411 while (dl_debug[len] != '\0' && dl_debug[len] != ' '
2412 && dl_debug[len] != ',' && dl_debug[len] != ':')
2413 ++len;
2415 for (cnt = 0; cnt < ndebopts; ++cnt)
2416 if (debopts[cnt].len == len
2417 && memcmp (dl_debug, debopts[cnt].name, len) == 0)
2419 GLRO(dl_debug_mask) |= debopts[cnt].mask;
2420 any_debug = 1;
2421 break;
2424 if (cnt == ndebopts)
2426 /* Display a warning and skip everything until next
2427 separator. */
2428 char *copy = strndupa (dl_debug, len);
2429 _dl_error_printf ("\
2430 warning: debug option `%s' unknown; try LD_DEBUG=help\n", copy);
2433 dl_debug += len;
2434 continue;
2437 ++dl_debug;
2440 if (GLRO(dl_debug_mask) & DL_DEBUG_HELP)
2442 size_t cnt;
2444 _dl_printf ("\
2445 Valid options for the LD_DEBUG environment variable are:\n\n");
2447 for (cnt = 0; cnt < ndebopts; ++cnt)
2448 _dl_printf (" %.*s%s%s\n", debopts[cnt].len, debopts[cnt].name,
2449 " " + debopts[cnt].len - 3,
2450 debopts[cnt].helptext);
2452 _dl_printf ("\n\
2453 To direct the debugging output into a file instead of standard output\n\
2454 a filename can be specified using the LD_DEBUG_OUTPUT environment variable.\n");
2455 _exit (0);
2459 static void
2460 process_dl_audit (char *str)
2462 /* The parameter is a colon separated list of DSO names. */
2463 char *p;
2465 while ((p = (strsep) (&str, ":")) != NULL)
2466 if (p[0] != '\0'
2467 && (__builtin_expect (! INTUSE(__libc_enable_secure), 1)
2468 || strchr (p, '/') == NULL))
2470 /* This is using the local malloc, not the system malloc. The
2471 memory can never be freed. */
2472 struct audit_list *newp = malloc (sizeof (*newp));
2473 newp->name = p;
2475 if (audit_list == NULL)
2476 audit_list = newp->next = newp;
2477 else
2479 newp->next = audit_list->next;
2480 audit_list = audit_list->next = newp;
2485 /* Process all environments variables the dynamic linker must recognize.
2486 Since all of them start with `LD_' we are a bit smarter while finding
2487 all the entries. */
2488 extern char **_environ attribute_hidden;
2491 static void
2492 process_envvars (enum mode *modep)
2494 char **runp = _environ;
2495 char *envline;
2496 enum mode mode = normal;
2497 char *debug_output = NULL;
2499 /* This is the default place for profiling data file. */
2500 GLRO(dl_profile_output)
2501 = &"/var/tmp\0/var/profile"[INTUSE(__libc_enable_secure) ? 9 : 0];
2503 while ((envline = _dl_next_ld_env_entry (&runp)) != NULL)
2505 size_t len = 0;
2507 while (envline[len] != '\0' && envline[len] != '=')
2508 ++len;
2510 if (envline[len] != '=')
2511 /* This is a "LD_" variable at the end of the string without
2512 a '=' character. Ignore it since otherwise we will access
2513 invalid memory below. */
2514 continue;
2516 switch (len)
2518 case 4:
2519 /* Warning level, verbose or not. */
2520 if (memcmp (envline, "WARN", 4) == 0)
2521 GLRO(dl_verbose) = envline[5] != '\0';
2522 break;
2524 case 5:
2525 /* Debugging of the dynamic linker? */
2526 if (memcmp (envline, "DEBUG", 5) == 0)
2528 process_dl_debug (&envline[6]);
2529 break;
2531 if (memcmp (envline, "AUDIT", 5) == 0)
2532 process_dl_audit (&envline[6]);
2533 break;
2535 case 7:
2536 /* Print information about versions. */
2537 if (memcmp (envline, "VERBOSE", 7) == 0)
2539 version_info = envline[8] != '\0';
2540 break;
2543 /* List of objects to be preloaded. */
2544 if (memcmp (envline, "PRELOAD", 7) == 0)
2546 preloadlist = &envline[8];
2547 break;
2550 /* Which shared object shall be profiled. */
2551 if (memcmp (envline, "PROFILE", 7) == 0 && envline[8] != '\0')
2552 GLRO(dl_profile) = &envline[8];
2553 break;
2555 case 8:
2556 /* Do we bind early? */
2557 if (memcmp (envline, "BIND_NOW", 8) == 0)
2559 GLRO(dl_lazy) = envline[9] == '\0';
2560 break;
2562 if (memcmp (envline, "BIND_NOT", 8) == 0)
2563 GLRO(dl_bind_not) = envline[9] != '\0';
2564 break;
2566 case 9:
2567 /* Test whether we want to see the content of the auxiliary
2568 array passed up from the kernel. */
2569 if (!INTUSE(__libc_enable_secure)
2570 && memcmp (envline, "SHOW_AUXV", 9) == 0)
2571 _dl_show_auxv ();
2572 break;
2574 case 10:
2575 /* Mask for the important hardware capabilities. */
2576 if (memcmp (envline, "HWCAP_MASK", 10) == 0)
2577 GLRO(dl_hwcap_mask) = __strtoul_internal (&envline[11], NULL,
2578 0, 0);
2579 break;
2581 case 11:
2582 /* Path where the binary is found. */
2583 if (!INTUSE(__libc_enable_secure)
2584 && memcmp (envline, "ORIGIN_PATH", 11) == 0)
2585 GLRO(dl_origin_path) = &envline[12];
2586 break;
2588 case 12:
2589 /* The library search path. */
2590 if (memcmp (envline, "LIBRARY_PATH", 12) == 0)
2592 library_path = &envline[13];
2593 break;
2596 /* Where to place the profiling data file. */
2597 if (memcmp (envline, "DEBUG_OUTPUT", 12) == 0)
2599 debug_output = &envline[13];
2600 break;
2603 if (!INTUSE(__libc_enable_secure)
2604 && memcmp (envline, "DYNAMIC_WEAK", 12) == 0)
2605 GLRO(dl_dynamic_weak) = 1;
2606 break;
2608 case 13:
2609 /* We might have some extra environment variable with length 13
2610 to handle. */
2611 #ifdef EXTRA_LD_ENVVARS_13
2612 EXTRA_LD_ENVVARS_13
2613 #endif
2614 if (!INTUSE(__libc_enable_secure)
2615 && memcmp (envline, "USE_LOAD_BIAS", 13) == 0)
2617 GLRO(dl_use_load_bias) = envline[14] == '1' ? -1 : 0;
2618 break;
2621 if (memcmp (envline, "POINTER_GUARD", 13) == 0)
2622 GLRO(dl_pointer_guard) = envline[14] != '0';
2623 break;
2625 case 14:
2626 /* Where to place the profiling data file. */
2627 if (!INTUSE(__libc_enable_secure)
2628 && memcmp (envline, "PROFILE_OUTPUT", 14) == 0
2629 && envline[15] != '\0')
2630 GLRO(dl_profile_output) = &envline[15];
2631 break;
2633 case 16:
2634 /* The mode of the dynamic linker can be set. */
2635 if (memcmp (envline, "TRACE_PRELINKING", 16) == 0)
2637 mode = trace;
2638 GLRO(dl_verbose) = 1;
2639 GLRO(dl_debug_mask) |= DL_DEBUG_PRELINK;
2640 GLRO(dl_trace_prelink) = &envline[17];
2642 break;
2644 case 20:
2645 /* The mode of the dynamic linker can be set. */
2646 if (memcmp (envline, "TRACE_LOADED_OBJECTS", 20) == 0)
2647 mode = trace;
2648 break;
2650 /* We might have some extra environment variable to handle. This
2651 is tricky due to the pre-processing of the length of the name
2652 in the switch statement here. The code here assumes that added
2653 environment variables have a different length. */
2654 #ifdef EXTRA_LD_ENVVARS
2655 EXTRA_LD_ENVVARS
2656 #endif
2660 /* The caller wants this information. */
2661 *modep = mode;
2663 /* Extra security for SUID binaries. Remove all dangerous environment
2664 variables. */
2665 if (__builtin_expect (INTUSE(__libc_enable_secure), 0))
2667 static const char unsecure_envvars[] =
2668 #ifdef EXTRA_UNSECURE_ENVVARS
2669 EXTRA_UNSECURE_ENVVARS
2670 #endif
2671 UNSECURE_ENVVARS;
2672 const char *nextp;
2674 nextp = unsecure_envvars;
2677 unsetenv (nextp);
2678 /* We could use rawmemchr but this need not be fast. */
2679 nextp = (char *) (strchr) (nextp, '\0') + 1;
2681 while (*nextp != '\0');
2683 if (__access ("/etc/suid-debug", F_OK) != 0)
2685 unsetenv ("MALLOC_CHECK_");
2686 GLRO(dl_debug_mask) = 0;
2689 if (mode != normal)
2690 _exit (5);
2692 /* If we have to run the dynamic linker in debugging mode and the
2693 LD_DEBUG_OUTPUT environment variable is given, we write the debug
2694 messages to this file. */
2695 else if (any_debug && debug_output != NULL)
2697 #ifdef O_NOFOLLOW
2698 const int flags = O_WRONLY | O_APPEND | O_CREAT | O_NOFOLLOW;
2699 #else
2700 const int flags = O_WRONLY | O_APPEND | O_CREAT;
2701 #endif
2702 size_t name_len = strlen (debug_output);
2703 char buf[name_len + 12];
2704 char *startp;
2706 buf[name_len + 11] = '\0';
2707 startp = _itoa (__getpid (), &buf[name_len + 11], 10, 0);
2708 *--startp = '.';
2709 startp = memcpy (startp - name_len, debug_output, name_len);
2711 GLRO(dl_debug_fd) = __open (startp, flags, DEFFILEMODE);
2712 if (GLRO(dl_debug_fd) == -1)
2713 /* We use standard output if opening the file failed. */
2714 GLRO(dl_debug_fd) = STDOUT_FILENO;
2719 /* Print the various times we collected. */
2720 static void
2721 __attribute ((noinline))
2722 print_statistics (hp_timing_t *rtld_total_timep)
2724 #ifndef HP_TIMING_NONAVAIL
2725 char buf[200];
2726 char *cp;
2727 char *wp;
2729 /* Total time rtld used. */
2730 if (HP_TIMING_AVAIL)
2732 HP_TIMING_PRINT (buf, sizeof (buf), *rtld_total_timep);
2733 _dl_debug_printf ("\nruntime linker statistics:\n"
2734 " total startup time in dynamic loader: %s\n", buf);
2736 /* Print relocation statistics. */
2737 char pbuf[30];
2738 HP_TIMING_PRINT (buf, sizeof (buf), relocate_time);
2739 cp = _itoa ((1000ULL * relocate_time) / *rtld_total_timep,
2740 pbuf + sizeof (pbuf), 10, 0);
2741 wp = pbuf;
2742 switch (pbuf + sizeof (pbuf) - cp)
2744 case 3:
2745 *wp++ = *cp++;
2746 case 2:
2747 *wp++ = *cp++;
2748 case 1:
2749 *wp++ = '.';
2750 *wp++ = *cp++;
2752 *wp = '\0';
2753 _dl_debug_printf ("\
2754 time needed for relocation: %s (%s%%)\n", buf, pbuf);
2756 #endif
2758 unsigned long int num_relative_relocations = 0;
2759 for (Lmid_t ns = 0; ns < DL_NNS; ++ns)
2761 if (GL(dl_ns)[ns]._ns_loaded == NULL)
2762 continue;
2764 struct r_scope_elem *scope = &GL(dl_ns)[ns]._ns_loaded->l_searchlist;
2766 for (unsigned int i = 0; i < scope->r_nlist; i++)
2768 struct link_map *l = scope->r_list [i];
2770 if (l->l_addr != 0 && l->l_info[VERSYMIDX (DT_RELCOUNT)])
2771 num_relative_relocations
2772 += l->l_info[VERSYMIDX (DT_RELCOUNT)]->d_un.d_val;
2773 #ifndef ELF_MACHINE_REL_RELATIVE
2774 /* Relative relocations are processed on these architectures if
2775 library is loaded to different address than p_vaddr or
2776 if not prelinked. */
2777 if ((l->l_addr != 0 || !l->l_info[VALIDX(DT_GNU_PRELINKED)])
2778 && l->l_info[VERSYMIDX (DT_RELACOUNT)])
2779 #else
2780 /* On e.g. IA-64 or Alpha, relative relocations are processed
2781 only if library is loaded to different address than p_vaddr. */
2782 if (l->l_addr != 0 && l->l_info[VERSYMIDX (DT_RELACOUNT)])
2783 #endif
2784 num_relative_relocations
2785 += l->l_info[VERSYMIDX (DT_RELACOUNT)]->d_un.d_val;
2789 _dl_debug_printf (" number of relocations: %lu\n"
2790 " number of relocations from cache: %lu\n"
2791 " number of relative relocations: %lu\n",
2792 GL(dl_num_relocations),
2793 GL(dl_num_cache_relocations),
2794 num_relative_relocations);
2796 #ifndef HP_TIMING_NONAVAIL
2797 /* Time spend while loading the object and the dependencies. */
2798 if (HP_TIMING_AVAIL)
2800 char pbuf[30];
2801 HP_TIMING_PRINT (buf, sizeof (buf), load_time);
2802 cp = _itoa ((1000ULL * load_time) / *rtld_total_timep,
2803 pbuf + sizeof (pbuf), 10, 0);
2804 wp = pbuf;
2805 switch (pbuf + sizeof (pbuf) - cp)
2807 case 3:
2808 *wp++ = *cp++;
2809 case 2:
2810 *wp++ = *cp++;
2811 case 1:
2812 *wp++ = '.';
2813 *wp++ = *cp++;
2815 *wp = '\0';
2816 _dl_debug_printf ("\
2817 time needed to load objects: %s (%s%%)\n",
2818 buf, pbuf);
2820 #endif