1 /* Map in a shared object's segments from the file.
2 Copyright (C) 1995-2018 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
28 #include <bits/wordsize.h>
30 #include <sys/param.h>
32 #include <sys/types.h>
33 #include "dynamic-link.h"
35 #include <stackinfo.h>
37 #include <stap-probe.h>
38 #include <libc-pointer-arith.h>
39 #include <array_length.h>
43 #include <dl-map-segments.h>
44 #include <dl-unmap-segments.h>
45 #include <dl-machine-reject-phdr.h>
46 #include <dl-sysdep-open.h>
50 #if BYTE_ORDER == BIG_ENDIAN
51 # define byteorder ELFDATA2MSB
52 #elif BYTE_ORDER == LITTLE_ENDIAN
53 # define byteorder ELFDATA2LSB
55 # error "Unknown BYTE_ORDER " BYTE_ORDER
56 # define byteorder ELFDATANONE
59 #define STRING(x) __STRING (x)
62 int __stack_prot attribute_hidden attribute_relro
63 #if _STACK_GROWS_DOWN && defined PROT_GROWSDOWN
65 #elif _STACK_GROWS_UP && defined PROT_GROWSUP
72 /* Type for the buffer we put the ELF header and hopefully the program
73 header. This buffer does not really have to be too large. In most
74 cases the program header follows the ELF header directly. If this
75 is not the case all bets are off and we can make the header
76 arbitrarily large and still won't get it read. This means the only
77 question is how large are the ELF and program header combined. The
78 ELF header 32-bit files is 52 bytes long and in 64-bit files is 64
79 bytes long. Each program header entry is again 32 and 56 bytes
80 long respectively. I.e., even with a file which has 10 program
81 header entries we only have to read 372B/624B respectively. Add to
82 this a bit of margin for program notes and reading 512B and 832B
83 for 32-bit and 64-bit files respecitvely is enough. If this
84 heuristic should really fail for some file the code in
85 `_dl_map_object_from_fd' knows how to recover. */
90 # define FILEBUF_SIZE 512
92 # define FILEBUF_SIZE 832
94 char buf
[FILEBUF_SIZE
] __attribute__ ((aligned (__alignof (ElfW(Ehdr
)))));
97 /* This is the decomposed LD_LIBRARY_PATH search path. */
98 static struct r_search_path_struct env_path_list attribute_relro
;
100 /* List of the hardware capabilities we might end up using. */
101 static const struct r_strlenpair
*capstr attribute_relro
;
102 static size_t ncapstr attribute_relro
;
103 static size_t max_capstrlen attribute_relro
;
106 /* Get the generated information about the trusted directories. Use
107 an array of concatenated strings to avoid relocations. See
108 gen-trusted-dirs.awk. */
109 #include "trusted-dirs.h"
111 static const char system_dirs
[] = SYSTEM_DIRS
;
112 static const size_t system_dirs_len
[] =
116 #define nsystem_dirs_len array_length (system_dirs_len)
119 is_trusted_path_normalize (const char *path
, size_t len
)
130 char *npath
= (char *) alloca (len
+ 2);
132 while (*path
!= '\0')
138 if (path
[2] == '.' && (path
[3] == '/' || path
[3] == '\0'))
140 while (wnp
> npath
&& *--wnp
!= '/')
145 else if (path
[2] == '/' || path
[2] == '\0')
152 if (wnp
> npath
&& wnp
[-1] == '/')
162 if (wnp
== npath
|| wnp
[-1] != '/')
165 const char *trun
= system_dirs
;
167 for (size_t idx
= 0; idx
< nsystem_dirs_len
; ++idx
)
169 if (wnp
- npath
>= system_dirs_len
[idx
]
170 && memcmp (trun
, npath
, system_dirs_len
[idx
]) == 0)
174 trun
+= system_dirs_len
[idx
] + 1;
182 is_dst (const char *start
, const char *name
, const char *str
, int secure
)
185 bool is_curly
= false;
194 while (name
[len
] == str
[len
] && name
[len
] != '\0')
199 if (name
[len
] != '}')
202 /* Point again at the beginning of the name. */
204 /* Skip over closing curly brace and adjust for the --name. */
207 else if (name
[len
] != '\0' && name
[len
] != '/')
210 if (__glibc_unlikely (secure
)
211 && ((name
[len
] != '\0' && name
[len
] != '/')
212 || (name
!= start
+ 1)))
220 _dl_dst_count (const char *name
)
222 const char *const start
= name
;
229 /* $ORIGIN is not expanded for SUID/GUID programs (except if it
230 is $ORIGIN alone) and it must always appear first in path. */
232 if ((len
= is_dst (start
, name
, "ORIGIN", __libc_enable_secure
)) != 0
233 || (len
= is_dst (start
, name
, "PLATFORM", 0)) != 0
234 || (len
= is_dst (start
, name
, "LIB", 0)) != 0)
237 name
= strchr (name
+ len
, '$');
239 while (name
!= NULL
);
246 _dl_dst_substitute (struct link_map
*l
, const char *name
, char *result
)
248 const char *const start
= name
;
250 /* Now fill the result path. While copying over the string we keep
251 track of the start of the last path element. When we come across
252 a DST we copy over the value or (if the value is not available)
253 leave the entire path element out. */
255 char *last_elem
= result
;
256 bool check_for_trusted
= false;
260 if (__glibc_unlikely (*name
== '$'))
262 const char *repl
= NULL
;
266 if ((len
= is_dst (start
, name
, "ORIGIN", __libc_enable_secure
)) != 0)
269 check_for_trusted
= (__libc_enable_secure
270 && l
->l_type
== lt_executable
);
272 else if ((len
= is_dst (start
, name
, "PLATFORM", 0)) != 0)
273 repl
= GLRO(dl_platform
);
274 else if ((len
= is_dst (start
, name
, "LIB", 0)) != 0)
277 if (repl
!= NULL
&& repl
!= (const char *) -1)
279 wp
= __stpcpy (wp
, repl
);
284 /* We cannot use this path element, the value of the
285 replacement is unknown. */
290 /* No DST we recognize. */
298 while (*name
!= '\0');
300 /* In SUID/SGID programs, after $ORIGIN expansion the normalized
301 path must be rooted in one of the trusted directories. */
302 if (__glibc_unlikely (check_for_trusted
)
303 && !is_trusted_path_normalize (last_elem
, wp
- last_elem
))
312 /* Return copy of argument with all recognized dynamic string tokens
313 ($ORIGIN and $PLATFORM for now) replaced. On some platforms it
314 might not be possible to determine the path from which the object
315 belonging to the map is loaded. In this case the path element
316 containing $ORIGIN is left out. */
318 expand_dynamic_string_token (struct link_map
*l
, const char *s
)
320 /* We make two runs over the string. First we determine how large the
321 resulting string is and then we copy it over. Since this is no
322 frequently executed operation we are looking here not for performance
323 but rather for code size. */
328 /* Determine the number of DST elements. */
329 cnt
= DL_DST_COUNT (s
);
331 /* If we do not have to replace anything simply copy the string. */
332 if (__glibc_likely (cnt
== 0))
335 /* Determine the length of the substituted string. */
336 total
= DL_DST_REQUIRED (l
, s
, strlen (s
), cnt
);
338 /* Allocate the necessary memory. */
339 result
= (char *) malloc (total
+ 1);
343 return _dl_dst_substitute (l
, s
, result
);
347 /* Add `name' to the list of names for a particular shared object.
348 `name' is expected to have been allocated with malloc and will
349 be freed if the shared object already has this name.
350 Returns false if the object already had this name. */
352 add_name_to_object (struct link_map
*l
, const char *name
)
354 struct libname_list
*lnp
, *lastp
;
355 struct libname_list
*newname
;
359 for (lnp
= l
->l_libname
; lnp
!= NULL
; lastp
= lnp
, lnp
= lnp
->next
)
360 if (strcmp (name
, lnp
->name
) == 0)
363 name_len
= strlen (name
) + 1;
364 newname
= (struct libname_list
*) malloc (sizeof *newname
+ name_len
);
367 /* No more memory. */
368 _dl_signal_error (ENOMEM
, name
, NULL
, N_("cannot allocate name record"));
371 /* The object should have a libname set from _dl_new_object. */
372 assert (lastp
!= NULL
);
374 newname
->name
= memcpy (newname
+ 1, name
, name_len
);
375 newname
->next
= NULL
;
376 newname
->dont_free
= 0;
377 lastp
->next
= newname
;
380 /* Standard search directories. */
381 static struct r_search_path_struct rtld_search_dirs attribute_relro
;
383 static size_t max_dirnamelen
;
385 static struct r_search_path_elem
**
386 fillin_rpath (char *rpath
, struct r_search_path_elem
**result
, const char *sep
,
387 const char *what
, const char *where
, struct link_map
*l
)
392 while ((cp
= __strsep (&rpath
, sep
)) != NULL
)
394 struct r_search_path_elem
*dirp
;
395 char *to_free
= NULL
;
398 /* `strsep' can pass an empty string. */
401 to_free
= cp
= expand_dynamic_string_token (l
, cp
);
403 /* expand_dynamic_string_token can return NULL in case of empty
404 path or memory allocation failure. */
408 /* Compute the length after dynamic string token expansion and
409 ignore empty paths. */
417 /* Remove trailing slashes (except for "/"). */
418 while (len
> 1 && cp
[len
- 1] == '/')
421 /* Now add one if there is none so far. */
422 if (len
> 0 && cp
[len
- 1] != '/')
426 /* See if this directory is already known. */
427 for (dirp
= GL(dl_all_dirs
); dirp
!= NULL
; dirp
= dirp
->next
)
428 if (dirp
->dirnamelen
== len
&& memcmp (cp
, dirp
->dirname
, len
) == 0)
433 /* It is available, see whether it's on our own list. */
435 for (cnt
= 0; cnt
< nelems
; ++cnt
)
436 if (result
[cnt
] == dirp
)
440 result
[nelems
++] = dirp
;
445 enum r_dir_status init_val
;
446 size_t where_len
= where
? strlen (where
) + 1 : 0;
448 /* It's a new directory. Create an entry and add it. */
449 dirp
= (struct r_search_path_elem
*)
450 malloc (sizeof (*dirp
) + ncapstr
* sizeof (enum r_dir_status
)
451 + where_len
+ len
+ 1);
453 _dl_signal_error (ENOMEM
, NULL
, NULL
,
454 N_("cannot create cache for search path"));
456 dirp
->dirname
= ((char *) dirp
+ sizeof (*dirp
)
457 + ncapstr
* sizeof (enum r_dir_status
));
458 *((char *) __mempcpy ((char *) dirp
->dirname
, cp
, len
)) = '\0';
459 dirp
->dirnamelen
= len
;
461 if (len
> max_dirnamelen
)
462 max_dirnamelen
= len
;
464 /* We have to make sure all the relative directories are
465 never ignored. The current directory might change and
466 all our saved information would be void. */
467 init_val
= cp
[0] != '/' ? existing
: unknown
;
468 for (cnt
= 0; cnt
< ncapstr
; ++cnt
)
469 dirp
->status
[cnt
] = init_val
;
472 if (__glibc_likely (where
!= NULL
))
473 dirp
->where
= memcpy ((char *) dirp
+ sizeof (*dirp
) + len
+ 1
474 + (ncapstr
* sizeof (enum r_dir_status
)),
479 dirp
->next
= GL(dl_all_dirs
);
480 GL(dl_all_dirs
) = dirp
;
482 /* Put it in the result array. */
483 result
[nelems
++] = dirp
;
488 /* Terminate the array. */
489 result
[nelems
] = NULL
;
496 decompose_rpath (struct r_search_path_struct
*sps
,
497 const char *rpath
, struct link_map
*l
, const char *what
)
499 /* Make a copy we can work with. */
500 const char *where
= l
->l_name
;
502 struct r_search_path_elem
**result
;
504 /* Initialize to please the compiler. */
505 const char *errstring
= NULL
;
507 /* First see whether we must forget the RUNPATH and RPATH from this
509 if (__glibc_unlikely (GLRO(dl_inhibit_rpath
) != NULL
)
510 && !__libc_enable_secure
)
512 const char *inhp
= GLRO(dl_inhibit_rpath
);
516 const char *wp
= where
;
518 while (*inhp
== *wp
&& *wp
!= '\0')
524 if (*wp
== '\0' && (*inhp
== '\0' || *inhp
== ':'))
526 /* This object is on the list of objects for which the
527 RUNPATH and RPATH must not be used. */
528 sps
->dirs
= (void *) -1;
532 while (*inhp
!= '\0')
536 while (*inhp
!= '\0');
539 /* Ignore empty rpaths. */
542 sps
->dirs
= (struct r_search_path_elem
**) -1;
546 /* Make a writable copy. */
547 char *copy
= __strdup (rpath
);
550 errstring
= N_("cannot create RUNPATH/RPATH copy");
554 /* Count the number of necessary elements in the result array. */
556 for (cp
= copy
; *cp
!= '\0'; ++cp
)
560 /* Allocate room for the result. NELEMS + 1 is an upper limit for the
561 number of necessary entries. */
562 result
= (struct r_search_path_elem
**) malloc ((nelems
+ 1 + 1)
567 errstring
= N_("cannot create cache for search path");
569 _dl_signal_error (ENOMEM
, NULL
, NULL
, errstring
);
572 fillin_rpath (copy
, result
, ":", what
, where
, l
);
574 /* Free the copied RPATH string. `fillin_rpath' make own copies if
578 /* There is no path after expansion. */
579 if (result
[0] == NULL
)
582 sps
->dirs
= (struct r_search_path_elem
**) -1;
587 /* The caller will change this value if we haven't used a real malloc. */
592 /* Make sure cached path information is stored in *SP
593 and return true if there are any paths to search there. */
595 cache_rpath (struct link_map
*l
,
596 struct r_search_path_struct
*sp
,
600 if (sp
->dirs
== (void *) -1)
603 if (sp
->dirs
!= NULL
)
606 if (l
->l_info
[tag
] == NULL
)
608 /* There is no path. */
609 sp
->dirs
= (void *) -1;
613 /* Make sure the cache information is available. */
614 return decompose_rpath (sp
, (const char *) (D_PTR (l
, l_info
[DT_STRTAB
])
615 + l
->l_info
[tag
]->d_un
.d_val
),
621 _dl_init_paths (const char *llp
)
625 struct r_search_path_elem
*pelem
, **aelem
;
627 struct link_map
__attribute__ ((unused
)) *l
= NULL
;
628 /* Initialize to please the compiler. */
629 const char *errstring
= NULL
;
631 /* Fill in the information about the application's RPATH and the
632 directories addressed by the LD_LIBRARY_PATH environment variable. */
634 /* Get the capabilities. */
635 capstr
= _dl_important_hwcaps (GLRO(dl_platform
), GLRO(dl_platformlen
),
636 &ncapstr
, &max_capstrlen
);
638 /* First set up the rest of the default search directory entries. */
639 aelem
= rtld_search_dirs
.dirs
= (struct r_search_path_elem
**)
640 malloc ((nsystem_dirs_len
+ 1) * sizeof (struct r_search_path_elem
*));
641 if (rtld_search_dirs
.dirs
== NULL
)
643 errstring
= N_("cannot create search path array");
645 _dl_signal_error (ENOMEM
, NULL
, NULL
, errstring
);
648 round_size
= ((2 * sizeof (struct r_search_path_elem
) - 1
649 + ncapstr
* sizeof (enum r_dir_status
))
650 / sizeof (struct r_search_path_elem
));
652 rtld_search_dirs
.dirs
[0] = malloc (nsystem_dirs_len
* round_size
653 * sizeof (*rtld_search_dirs
.dirs
[0]));
654 if (rtld_search_dirs
.dirs
[0] == NULL
)
656 errstring
= N_("cannot create cache for search path");
660 rtld_search_dirs
.malloced
= 0;
661 pelem
= GL(dl_all_dirs
) = rtld_search_dirs
.dirs
[0];
671 pelem
->what
= "system search path";
674 pelem
->dirname
= strp
;
675 pelem
->dirnamelen
= system_dirs_len
[idx
];
676 strp
+= system_dirs_len
[idx
] + 1;
678 /* System paths must be absolute. */
679 assert (pelem
->dirname
[0] == '/');
680 for (cnt
= 0; cnt
< ncapstr
; ++cnt
)
681 pelem
->status
[cnt
] = unknown
;
683 pelem
->next
= (++idx
== nsystem_dirs_len
? NULL
: (pelem
+ round_size
));
687 while (idx
< nsystem_dirs_len
);
689 max_dirnamelen
= SYSTEM_DIRS_MAX_LEN
;
693 /* This points to the map of the main object. */
694 l
= GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
;
697 assert (l
->l_type
!= lt_loaded
);
699 if (l
->l_info
[DT_RUNPATH
])
701 /* Allocate room for the search path and fill in information
703 decompose_rpath (&l
->l_runpath_dirs
,
704 (const void *) (D_PTR (l
, l_info
[DT_STRTAB
])
705 + l
->l_info
[DT_RUNPATH
]->d_un
.d_val
),
707 /* During rtld init the memory is allocated by the stub malloc,
708 prevent any attempt to free it by the normal malloc. */
709 l
->l_runpath_dirs
.malloced
= 0;
711 /* The RPATH is ignored. */
712 l
->l_rpath_dirs
.dirs
= (void *) -1;
716 l
->l_runpath_dirs
.dirs
= (void *) -1;
718 if (l
->l_info
[DT_RPATH
])
720 /* Allocate room for the search path and fill in information
722 decompose_rpath (&l
->l_rpath_dirs
,
723 (const void *) (D_PTR (l
, l_info
[DT_STRTAB
])
724 + l
->l_info
[DT_RPATH
]->d_un
.d_val
),
726 /* During rtld init the memory is allocated by the stub
727 malloc, prevent any attempt to free it by the normal
729 l
->l_rpath_dirs
.malloced
= 0;
732 l
->l_rpath_dirs
.dirs
= (void *) -1;
737 if (llp
!= NULL
&& *llp
!= '\0')
739 char *llp_tmp
= strdupa (llp
);
741 /* Decompose the LD_LIBRARY_PATH contents. First determine how many
744 for (const char *cp
= llp_tmp
; *cp
!= '\0'; ++cp
)
745 if (*cp
== ':' || *cp
== ';')
748 env_path_list
.dirs
= (struct r_search_path_elem
**)
749 malloc ((nllp
+ 1) * sizeof (struct r_search_path_elem
*));
750 if (env_path_list
.dirs
== NULL
)
752 errstring
= N_("cannot create cache for search path");
756 (void) fillin_rpath (llp_tmp
, env_path_list
.dirs
, ":;",
757 "LD_LIBRARY_PATH", NULL
, l
);
759 if (env_path_list
.dirs
[0] == NULL
)
761 free (env_path_list
.dirs
);
762 env_path_list
.dirs
= (void *) -1;
765 env_path_list
.malloced
= 0;
768 env_path_list
.dirs
= (void *) -1;
773 __attribute__ ((noreturn
, noinline
))
774 lose (int code
, int fd
, const char *name
, char *realname
, struct link_map
*l
,
775 const char *msg
, struct r_debug
*r
, Lmid_t nsid
)
777 /* The file might already be closed. */
780 if (l
!= NULL
&& l
->l_origin
!= (char *) -1l)
781 free ((char *) l
->l_origin
);
787 r
->r_state
= RT_CONSISTENT
;
789 LIBC_PROBE (map_failed
, 2, nsid
, r
);
792 _dl_signal_error (code
, name
, NULL
, msg
);
796 /* Map in the shared object NAME, actually located in REALNAME, and already
799 #ifndef EXTERNAL_MAP_FROM_FD
803 _dl_map_object_from_fd (const char *name
, const char *origname
, int fd
,
804 struct filebuf
*fbp
, char *realname
,
805 struct link_map
*loader
, int l_type
, int mode
,
806 void **stack_endp
, Lmid_t nsid
)
808 struct link_map
*l
= NULL
;
809 const ElfW(Ehdr
) *header
;
810 const ElfW(Phdr
) *phdr
;
811 const ElfW(Phdr
) *ph
;
814 /* Initialize to keep the compiler happy. */
815 const char *errstring
= NULL
;
817 struct r_debug
*r
= _dl_debug_initialize (0, nsid
);
818 bool make_consistent
= false;
820 /* Get file information. */
822 if (__glibc_unlikely (!_dl_get_file_id (fd
, &id
)))
824 errstring
= N_("cannot stat shared object");
828 lose (errval
, fd
, name
, realname
, l
, errstring
,
829 make_consistent
? r
: NULL
, nsid
);
832 /* Look again to see if the real name matched another already loaded. */
833 for (l
= GL(dl_ns
)[nsid
]._ns_loaded
; l
!= NULL
; l
= l
->l_next
)
834 if (!l
->l_removed
&& _dl_file_id_match_p (&l
->l_file_id
, &id
))
836 /* The object is already loaded.
837 Just bump its reference count and return it. */
840 /* If the name is not in the list of names for this object add
843 add_name_to_object (l
, name
);
849 /* When loading into a namespace other than the base one we must
850 avoid loading ld.so since there can only be one copy. Ever. */
851 if (__glibc_unlikely (nsid
!= LM_ID_BASE
)
852 && (_dl_file_id_match_p (&id
, &GL(dl_rtld_map
).l_file_id
)
853 || _dl_name_match_p (name
, &GL(dl_rtld_map
))))
855 /* This is indeed ld.so. Create a new link_map which refers to
856 the real one for almost everything. */
857 l
= _dl_new_object (realname
, name
, l_type
, loader
, mode
, nsid
);
861 /* Refer to the real descriptor. */
862 l
->l_real
= &GL(dl_rtld_map
);
864 /* No need to bump the refcount of the real object, ld.so will
865 never be unloaded. */
868 /* Add the map for the mirrored object to the object list. */
869 _dl_add_to_namespace_list (l
, nsid
);
875 if (mode
& RTLD_NOLOAD
)
877 /* We are not supposed to load the object unless it is already
878 loaded. So return now. */
884 /* Print debugging message. */
885 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_FILES
))
886 _dl_debug_printf ("file=%s [%lu]; generating link map\n", name
, nsid
);
888 /* This is the ELF header. We read it in `open_verify'. */
889 header
= (void *) fbp
->buf
;
893 if (_dl_zerofd
== -1)
895 _dl_zerofd
= _dl_sysdep_open_zero_fill ();
896 if (_dl_zerofd
== -1)
900 _dl_signal_error (errno
, NULL
, NULL
,
901 N_("cannot open zero fill device"));
906 /* Signal that we are going to add new objects. */
907 if (r
->r_state
== RT_CONSISTENT
)
910 /* Auditing checkpoint: we are going to add new objects. */
911 if ((mode
& __RTLD_AUDIT
) == 0
912 && __glibc_unlikely (GLRO(dl_naudit
) > 0))
914 struct link_map
*head
= GL(dl_ns
)[nsid
]._ns_loaded
;
915 /* Do not call the functions for any auditing object. */
916 if (head
->l_auditing
== 0)
918 struct audit_ifaces
*afct
= GLRO(dl_audit
);
919 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
921 if (afct
->activity
!= NULL
)
922 afct
->activity (&head
->l_audit
[cnt
].cookie
, LA_ACT_ADD
);
930 /* Notify the debugger we have added some objects. We need to
931 call _dl_debug_initialize in a static program in case dynamic
932 linking has not been used before. */
935 LIBC_PROBE (map_start
, 2, nsid
, r
);
936 make_consistent
= true;
939 assert (r
->r_state
== RT_ADD
);
941 /* Enter the new object in the list of loaded objects. */
942 l
= _dl_new_object (realname
, name
, l_type
, loader
, mode
, nsid
);
943 if (__glibc_unlikely (l
== NULL
))
948 errstring
= N_("cannot create shared object descriptor");
949 goto call_lose_errno
;
952 /* Extract the remaining details we need from the ELF header
953 and then read in the program header table. */
954 l
->l_entry
= header
->e_entry
;
955 type
= header
->e_type
;
956 l
->l_phnum
= header
->e_phnum
;
958 maplength
= header
->e_phnum
* sizeof (ElfW(Phdr
));
959 if (header
->e_phoff
+ maplength
<= (size_t) fbp
->len
)
960 phdr
= (void *) (fbp
->buf
+ header
->e_phoff
);
963 phdr
= alloca (maplength
);
964 __lseek (fd
, header
->e_phoff
, SEEK_SET
);
965 if ((size_t) __libc_read (fd
, (void *) phdr
, maplength
) != maplength
)
967 errstring
= N_("cannot read file data");
968 goto call_lose_errno
;
972 /* On most platforms presume that PT_GNU_STACK is absent and the stack is
973 * executable. Other platforms default to a nonexecutable stack and don't
974 * need PT_GNU_STACK to do so. */
975 uint_fast16_t stack_flags
= DEFAULT_STACK_PERMS
;
978 /* Scan the program header table, collecting its load commands. */
979 struct loadcmd loadcmds
[l
->l_phnum
];
980 size_t nloadcmds
= 0;
981 bool has_holes
= false;
983 /* The struct is initialized to zero so this is not necessary:
987 for (ph
= phdr
; ph
< &phdr
[l
->l_phnum
]; ++ph
)
990 /* These entries tell us where to find things once the file's
991 segments are mapped in. We record the addresses it says
992 verbatim, and later correct for the run-time load address. */
996 /* Debuginfo only files from "objcopy --only-keep-debug"
997 contain a PT_DYNAMIC segment with p_filesz == 0. Skip
998 such a segment to avoid a crash later. */
999 l
->l_ld
= (void *) ph
->p_vaddr
;
1000 l
->l_ldnum
= ph
->p_memsz
/ sizeof (ElfW(Dyn
));
1005 l
->l_phdr
= (void *) ph
->p_vaddr
;
1009 /* A load command tells us to map in part of the file.
1010 We record the load commands and process them all later. */
1011 if (__glibc_unlikely ((ph
->p_align
& (GLRO(dl_pagesize
) - 1)) != 0))
1013 errstring
= N_("ELF load command alignment not page-aligned");
1016 if (__glibc_unlikely (((ph
->p_vaddr
- ph
->p_offset
)
1017 & (ph
->p_align
- 1)) != 0))
1020 = N_("ELF load command address/offset not properly aligned");
1024 struct loadcmd
*c
= &loadcmds
[nloadcmds
++];
1025 c
->mapstart
= ALIGN_DOWN (ph
->p_vaddr
, GLRO(dl_pagesize
));
1026 c
->mapend
= ALIGN_UP (ph
->p_vaddr
+ ph
->p_filesz
, GLRO(dl_pagesize
));
1027 c
->dataend
= ph
->p_vaddr
+ ph
->p_filesz
;
1028 c
->allocend
= ph
->p_vaddr
+ ph
->p_memsz
;
1029 c
->mapoff
= ALIGN_DOWN (ph
->p_offset
, GLRO(dl_pagesize
));
1031 /* Determine whether there is a gap between the last segment
1033 if (nloadcmds
> 1 && c
[-1].mapend
!= c
->mapstart
)
1036 /* Optimize a common case. */
1037 #if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7
1038 c
->prot
= (PF_TO_PROT
1039 >> ((ph
->p_flags
& (PF_R
| PF_W
| PF_X
)) * 4)) & 0xf;
1042 if (ph
->p_flags
& PF_R
)
1043 c
->prot
|= PROT_READ
;
1044 if (ph
->p_flags
& PF_W
)
1045 c
->prot
|= PROT_WRITE
;
1046 if (ph
->p_flags
& PF_X
)
1047 c
->prot
|= PROT_EXEC
;
1052 if (ph
->p_memsz
== 0)
1053 /* Nothing to do for an empty segment. */
1056 l
->l_tls_blocksize
= ph
->p_memsz
;
1057 l
->l_tls_align
= ph
->p_align
;
1058 if (ph
->p_align
== 0)
1059 l
->l_tls_firstbyte_offset
= 0;
1061 l
->l_tls_firstbyte_offset
= ph
->p_vaddr
& (ph
->p_align
- 1);
1062 l
->l_tls_initimage_size
= ph
->p_filesz
;
1063 /* Since we don't know the load address yet only store the
1064 offset. We will adjust it later. */
1065 l
->l_tls_initimage
= (void *) ph
->p_vaddr
;
1067 /* If not loading the initial set of shared libraries,
1068 check whether we should permit loading a TLS segment. */
1069 if (__glibc_likely (l
->l_type
== lt_library
)
1070 /* If GL(dl_tls_dtv_slotinfo_list) == NULL, then rtld.c did
1071 not set up TLS data structures, so don't use them now. */
1072 || __glibc_likely (GL(dl_tls_dtv_slotinfo_list
) != NULL
))
1074 /* Assign the next available module ID. */
1075 l
->l_tls_modid
= _dl_next_tls_modid ();
1080 /* We are loading the executable itself when the dynamic
1081 linker was executed directly. The setup will happen
1082 later. Otherwise, the TLS data structures are already
1083 initialized, and we assigned a TLS modid above. */
1084 assert (l
->l_prev
== NULL
|| (mode
& __RTLD_AUDIT
) != 0);
1086 assert (false && "TLS not initialized in static application");
1091 stack_flags
= ph
->p_flags
;
1095 l
->l_relro_addr
= ph
->p_vaddr
;
1096 l
->l_relro_size
= ph
->p_memsz
;
1100 if (__glibc_unlikely (nloadcmds
== 0))
1102 /* This only happens for a bogus object that will be caught with
1103 another error below. But we don't want to go through the
1104 calculations below using NLOADCMDS - 1. */
1105 errstring
= N_("object file has no loadable segments");
1109 if (__glibc_unlikely (type
!= ET_DYN
)
1110 && __glibc_unlikely ((mode
& __RTLD_OPENEXEC
) == 0))
1112 /* This object is loaded at a fixed address. This must never
1113 happen for objects loaded with dlopen. */
1114 errstring
= N_("cannot dynamically load executable");
1118 /* Length of the sections to be loaded. */
1119 maplength
= loadcmds
[nloadcmds
- 1].allocend
- loadcmds
[0].mapstart
;
1121 /* Now process the load commands and map segments into memory.
1122 This is responsible for filling in:
1123 l_map_start, l_map_end, l_addr, l_contiguous, l_text_end, l_phdr
1125 errstring
= _dl_map_segments (l
, fd
, header
, type
, loadcmds
, nloadcmds
,
1126 maplength
, has_holes
, loader
);
1127 if (__glibc_unlikely (errstring
!= NULL
))
1133 if (__glibc_unlikely (type
== ET_DYN
))
1135 errstring
= N_("object file has no dynamic section");
1140 l
->l_ld
= (ElfW(Dyn
) *) ((ElfW(Addr
)) l
->l_ld
+ l
->l_addr
);
1142 elf_get_dynamic_info (l
, NULL
);
1144 /* Make sure we are not dlopen'ing an object that has the
1145 DF_1_NOOPEN flag set. */
1146 if (__glibc_unlikely (l
->l_flags_1
& DF_1_NOOPEN
)
1147 && (mode
& __RTLD_DLOPEN
))
1149 /* We are not supposed to load this object. Free all resources. */
1150 _dl_unmap_segments (l
);
1152 if (!l
->l_libname
->dont_free
)
1153 free (l
->l_libname
);
1155 if (l
->l_phdr_allocated
)
1156 free ((void *) l
->l_phdr
);
1158 errstring
= N_("shared object cannot be dlopen()ed");
1162 if (l
->l_phdr
== NULL
)
1164 /* The program header is not contained in any of the segments.
1165 We have to allocate memory ourself and copy it over from out
1167 ElfW(Phdr
) *newp
= (ElfW(Phdr
) *) malloc (header
->e_phnum
1168 * sizeof (ElfW(Phdr
)));
1171 errstring
= N_("cannot allocate memory for program header");
1172 goto call_lose_errno
;
1175 l
->l_phdr
= memcpy (newp
, phdr
,
1176 (header
->e_phnum
* sizeof (ElfW(Phdr
))));
1177 l
->l_phdr_allocated
= 1;
1180 /* Adjust the PT_PHDR value by the runtime load address. */
1181 l
->l_phdr
= (ElfW(Phdr
) *) ((ElfW(Addr
)) l
->l_phdr
+ l
->l_addr
);
1183 if (__glibc_unlikely ((stack_flags
&~ GL(dl_stack_flags
)) & PF_X
))
1185 /* The stack is presently not executable, but this module
1186 requires that it be executable. We must change the
1187 protection of the variable which contains the flags used in
1188 the mprotect calls. */
1190 if ((mode
& (__RTLD_DLOPEN
| __RTLD_AUDIT
)) == __RTLD_DLOPEN
)
1192 const uintptr_t p
= (uintptr_t) &__stack_prot
& -GLRO(dl_pagesize
);
1193 const size_t s
= (uintptr_t) (&__stack_prot
+ 1) - p
;
1195 struct link_map
*const m
= &GL(dl_rtld_map
);
1196 const uintptr_t relro_end
= ((m
->l_addr
+ m
->l_relro_addr
1198 & -GLRO(dl_pagesize
));
1199 if (__glibc_likely (p
+ s
<= relro_end
))
1201 /* The variable lies in the region protected by RELRO. */
1202 if (__mprotect ((void *) p
, s
, PROT_READ
|PROT_WRITE
) < 0)
1204 errstring
= N_("cannot change memory protections");
1205 goto call_lose_errno
;
1207 __stack_prot
|= PROT_READ
|PROT_WRITE
|PROT_EXEC
;
1208 __mprotect ((void *) p
, s
, PROT_READ
);
1211 __stack_prot
|= PROT_READ
|PROT_WRITE
|PROT_EXEC
;
1215 __stack_prot
|= PROT_READ
|PROT_WRITE
|PROT_EXEC
;
1217 #ifdef check_consistency
1218 check_consistency ();
1221 errval
= (*GL(dl_make_stack_executable_hook
)) (stack_endp
);
1225 cannot enable executable stack as shared object requires");
1230 /* Adjust the address of the TLS initialization image. */
1231 if (l
->l_tls_initimage
!= NULL
)
1232 l
->l_tls_initimage
= (char *) l
->l_tls_initimage
+ l
->l_addr
;
1234 /* We are done mapping in the file. We no longer need the descriptor. */
1235 if (__glibc_unlikely (__close (fd
) != 0))
1237 errstring
= N_("cannot close file descriptor");
1238 goto call_lose_errno
;
1240 /* Signal that we closed the file. */
1243 /* If this is ET_EXEC, we should have loaded it as lt_executable. */
1244 assert (type
!= ET_EXEC
|| l
->l_type
== lt_executable
);
1246 l
->l_entry
+= l
->l_addr
;
1248 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_FILES
))
1249 _dl_debug_printf ("\
1250 dynamic: 0x%0*lx base: 0x%0*lx size: 0x%0*Zx\n\
1251 entry: 0x%0*lx phdr: 0x%0*lx phnum: %*u\n\n",
1252 (int) sizeof (void *) * 2,
1253 (unsigned long int) l
->l_ld
,
1254 (int) sizeof (void *) * 2,
1255 (unsigned long int) l
->l_addr
,
1256 (int) sizeof (void *) * 2, maplength
,
1257 (int) sizeof (void *) * 2,
1258 (unsigned long int) l
->l_entry
,
1259 (int) sizeof (void *) * 2,
1260 (unsigned long int) l
->l_phdr
,
1261 (int) sizeof (void *) * 2, l
->l_phnum
);
1263 /* Set up the symbol hash table. */
1266 /* If this object has DT_SYMBOLIC set modify now its scope. We don't
1267 have to do this for the main map. */
1268 if ((mode
& RTLD_DEEPBIND
) == 0
1269 && __glibc_unlikely (l
->l_info
[DT_SYMBOLIC
] != NULL
)
1270 && &l
->l_searchlist
!= l
->l_scope
[0])
1272 /* Create an appropriate searchlist. It contains only this map.
1273 This is the definition of DT_SYMBOLIC in SysVr4. */
1274 l
->l_symbolic_searchlist
.r_list
[0] = l
;
1275 l
->l_symbolic_searchlist
.r_nlist
= 1;
1277 /* Now move the existing entries one back. */
1278 memmove (&l
->l_scope
[1], &l
->l_scope
[0],
1279 (l
->l_scope_max
- 1) * sizeof (l
->l_scope
[0]));
1281 /* Now add the new entry. */
1282 l
->l_scope
[0] = &l
->l_symbolic_searchlist
;
1285 /* Remember whether this object must be initialized first. */
1286 if (l
->l_flags_1
& DF_1_INITFIRST
)
1287 GL(dl_initfirst
) = l
;
1289 /* Finally the file information. */
1293 /* When auditing is used the recorded names might not include the
1294 name by which the DSO is actually known. Add that as well. */
1295 if (__glibc_unlikely (origname
!= NULL
))
1296 add_name_to_object (l
, origname
);
1298 /* Audit modules only exist when linking is dynamic so ORIGNAME
1299 cannot be non-NULL. */
1300 assert (origname
== NULL
);
1303 /* When we profile the SONAME might be needed for something else but
1304 loading. Add it right away. */
1305 if (__glibc_unlikely (GLRO(dl_profile
) != NULL
)
1306 && l
->l_info
[DT_SONAME
] != NULL
)
1307 add_name_to_object (l
, ((const char *) D_PTR (l
, l_info
[DT_STRTAB
])
1308 + l
->l_info
[DT_SONAME
]->d_un
.d_val
));
1310 #ifdef DL_AFTER_LOAD
1314 /* Now that the object is fully initialized add it to the object list. */
1315 _dl_add_to_namespace_list (l
, nsid
);
1318 /* Auditing checkpoint: we have a new object. */
1319 if (__glibc_unlikely (GLRO(dl_naudit
) > 0)
1320 && !GL(dl_ns
)[l
->l_ns
]._ns_loaded
->l_auditing
)
1322 struct audit_ifaces
*afct
= GLRO(dl_audit
);
1323 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
1325 if (afct
->objopen
!= NULL
)
1327 l
->l_audit
[cnt
].bindflags
1328 = afct
->objopen (l
, nsid
, &l
->l_audit
[cnt
].cookie
);
1330 l
->l_audit_any_plt
|= l
->l_audit
[cnt
].bindflags
!= 0;
1341 /* Print search path. */
1343 print_search_path (struct r_search_path_elem
**list
,
1344 const char *what
, const char *name
)
1346 char buf
[max_dirnamelen
+ max_capstrlen
];
1349 _dl_debug_printf (" search path=");
1351 while (*list
!= NULL
&& (*list
)->what
== what
) /* Yes, ==. */
1353 char *endp
= __mempcpy (buf
, (*list
)->dirname
, (*list
)->dirnamelen
);
1356 for (cnt
= 0; cnt
< ncapstr
; ++cnt
)
1357 if ((*list
)->status
[cnt
] != nonexisting
)
1359 char *cp
= __mempcpy (endp
, capstr
[cnt
].str
, capstr
[cnt
].len
);
1360 if (cp
== buf
|| (cp
== buf
+ 1 && buf
[0] == '/'))
1365 _dl_debug_printf_c (first
? "%s" : ":%s", buf
);
1373 _dl_debug_printf_c ("\t\t(%s from file %s)\n", what
,
1374 DSO_FILENAME (name
));
1376 _dl_debug_printf_c ("\t\t(%s)\n", what
);
1379 /* Open a file and verify it is an ELF file for this architecture. We
1380 ignore only ELF files for other architectures. Non-ELF files and
1381 ELF files with different header information cause fatal errors since
1382 this could mean there is something wrong in the installation and the
1383 user might want to know about this.
1385 If FD is not -1, then the file is already open and FD refers to it.
1386 In that case, FD is consumed for both successful and error returns. */
1388 open_verify (const char *name
, int fd
,
1389 struct filebuf
*fbp
, struct link_map
*loader
,
1390 int whatcode
, int mode
, bool *found_other_class
, bool free_name
)
1392 /* This is the expected ELF header. */
1393 #define ELF32_CLASS ELFCLASS32
1394 #define ELF64_CLASS ELFCLASS64
1395 #ifndef VALID_ELF_HEADER
1396 # define VALID_ELF_HEADER(hdr,exp,size) (memcmp (hdr, exp, size) == 0)
1397 # define VALID_ELF_OSABI(osabi) (osabi == ELFOSABI_SYSV)
1398 # define VALID_ELF_ABIVERSION(osabi,ver) (ver == 0)
1399 #elif defined MORE_ELF_HEADER_DATA
1400 MORE_ELF_HEADER_DATA
;
1402 static const unsigned char expected
[EI_NIDENT
] =
1404 [EI_MAG0
] = ELFMAG0
,
1405 [EI_MAG1
] = ELFMAG1
,
1406 [EI_MAG2
] = ELFMAG2
,
1407 [EI_MAG3
] = ELFMAG3
,
1408 [EI_CLASS
] = ELFW(CLASS
),
1409 [EI_DATA
] = byteorder
,
1410 [EI_VERSION
] = EV_CURRENT
,
1411 [EI_OSABI
] = ELFOSABI_SYSV
,
1416 ElfW(Word
) vendorlen
;
1420 } expected_note
= { 4, 16, 1, "GNU" };
1421 /* Initialize it to make the compiler happy. */
1422 const char *errstring
= NULL
;
1426 /* Give the auditing libraries a chance. */
1427 if (__glibc_unlikely (GLRO(dl_naudit
) > 0) && whatcode
!= 0
1428 && loader
->l_auditing
== 0)
1430 const char *original_name
= name
;
1431 struct audit_ifaces
*afct
= GLRO(dl_audit
);
1432 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
1434 if (afct
->objsearch
!= NULL
)
1436 name
= afct
->objsearch (name
, &loader
->l_audit
[cnt
].cookie
,
1439 /* Ignore the path. */
1446 if (fd
!= -1 && name
!= original_name
&& strcmp (name
, original_name
))
1448 /* An audit library changed what we're supposed to open,
1449 so FD no longer matches it. */
1457 /* Open the file. We always open files read-only. */
1458 fd
= __open (name
, O_RDONLY
| O_CLOEXEC
);
1463 ElfW(Phdr
) *phdr
, *ph
;
1464 ElfW(Word
) *abi_note
;
1465 ElfW(Word
) *abi_note_malloced
= NULL
;
1466 unsigned int osversion
;
1469 /* We successfully opened the file. Now verify it is a file
1473 assert (sizeof (fbp
->buf
) > sizeof (ElfW(Ehdr
)));
1474 /* Read in the header. */
1477 ssize_t retlen
= __libc_read (fd
, fbp
->buf
+ fbp
->len
,
1478 sizeof (fbp
->buf
) - fbp
->len
);
1483 while (__glibc_unlikely (fbp
->len
< sizeof (ElfW(Ehdr
))));
1485 /* This is where the ELF header is loaded. */
1486 ehdr
= (ElfW(Ehdr
) *) fbp
->buf
;
1488 /* Now run the tests. */
1489 if (__glibc_unlikely (fbp
->len
< (ssize_t
) sizeof (ElfW(Ehdr
))))
1492 errstring
= (errval
== 0
1493 ? N_("file too short") : N_("cannot read file data"));
1497 char *realname
= (char *) name
;
1498 name
= strdupa (realname
);
1501 lose (errval
, fd
, name
, NULL
, NULL
, errstring
, NULL
, 0);
1504 /* See whether the ELF header is what we expect. */
1505 if (__glibc_unlikely (! VALID_ELF_HEADER (ehdr
->e_ident
, expected
,
1507 || !VALID_ELF_ABIVERSION (ehdr
->e_ident
[EI_OSABI
],
1508 ehdr
->e_ident
[EI_ABIVERSION
])
1509 || memcmp (&ehdr
->e_ident
[EI_PAD
],
1511 EI_NIDENT
- EI_PAD
) != 0))
1513 /* Something is wrong. */
1514 const Elf32_Word
*magp
= (const void *) ehdr
->e_ident
;
1516 #if BYTE_ORDER == LITTLE_ENDIAN
1517 ((ELFMAG0
<< (EI_MAG0
* 8)) |
1518 (ELFMAG1
<< (EI_MAG1
* 8)) |
1519 (ELFMAG2
<< (EI_MAG2
* 8)) |
1520 (ELFMAG3
<< (EI_MAG3
* 8)))
1522 ((ELFMAG0
<< (EI_MAG3
* 8)) |
1523 (ELFMAG1
<< (EI_MAG2
* 8)) |
1524 (ELFMAG2
<< (EI_MAG1
* 8)) |
1525 (ELFMAG3
<< (EI_MAG0
* 8)))
1528 errstring
= N_("invalid ELF header");
1529 else if (ehdr
->e_ident
[EI_CLASS
] != ELFW(CLASS
))
1531 /* This is not a fatal error. On architectures where
1532 32-bit and 64-bit binaries can be run this might
1534 *found_other_class
= true;
1537 else if (ehdr
->e_ident
[EI_DATA
] != byteorder
)
1539 if (BYTE_ORDER
== BIG_ENDIAN
)
1540 errstring
= N_("ELF file data encoding not big-endian");
1542 errstring
= N_("ELF file data encoding not little-endian");
1544 else if (ehdr
->e_ident
[EI_VERSION
] != EV_CURRENT
)
1546 = N_("ELF file version ident does not match current one");
1547 /* XXX We should be able so set system specific versions which are
1549 else if (!VALID_ELF_OSABI (ehdr
->e_ident
[EI_OSABI
]))
1550 errstring
= N_("ELF file OS ABI invalid");
1551 else if (!VALID_ELF_ABIVERSION (ehdr
->e_ident
[EI_OSABI
],
1552 ehdr
->e_ident
[EI_ABIVERSION
]))
1553 errstring
= N_("ELF file ABI version invalid");
1554 else if (memcmp (&ehdr
->e_ident
[EI_PAD
], &expected
[EI_PAD
],
1555 EI_NIDENT
- EI_PAD
) != 0)
1556 errstring
= N_("nonzero padding in e_ident");
1558 /* Otherwise we don't know what went wrong. */
1559 errstring
= N_("internal error");
1564 if (__glibc_unlikely (ehdr
->e_version
!= EV_CURRENT
))
1566 errstring
= N_("ELF file version does not match current one");
1569 if (! __glibc_likely (elf_machine_matches_host (ehdr
)))
1571 else if (__glibc_unlikely (ehdr
->e_type
!= ET_DYN
1572 && ehdr
->e_type
!= ET_EXEC
))
1574 errstring
= N_("only ET_DYN and ET_EXEC can be loaded");
1577 else if (__glibc_unlikely (ehdr
->e_type
== ET_EXEC
1578 && (mode
& __RTLD_OPENEXEC
) == 0))
1580 /* BZ #16634. It is an error to dlopen ET_EXEC (unless
1581 __RTLD_OPENEXEC is explicitly set). We return error here
1582 so that code in _dl_map_object_from_fd does not try to set
1583 l_tls_modid for this module. */
1585 errstring
= N_("cannot dynamically load executable");
1588 else if (__glibc_unlikely (ehdr
->e_phentsize
!= sizeof (ElfW(Phdr
))))
1590 errstring
= N_("ELF file's phentsize not the expected size");
1594 maplength
= ehdr
->e_phnum
* sizeof (ElfW(Phdr
));
1595 if (ehdr
->e_phoff
+ maplength
<= (size_t) fbp
->len
)
1596 phdr
= (void *) (fbp
->buf
+ ehdr
->e_phoff
);
1599 phdr
= alloca (maplength
);
1600 __lseek (fd
, ehdr
->e_phoff
, SEEK_SET
);
1601 if ((size_t) __libc_read (fd
, (void *) phdr
, maplength
) != maplength
)
1605 errstring
= N_("cannot read file data");
1610 if (__glibc_unlikely (elf_machine_reject_phdr_p
1611 (phdr
, ehdr
->e_phnum
, fbp
->buf
, fbp
->len
,
1615 /* Check .note.ABI-tag if present. */
1616 for (ph
= phdr
; ph
< &phdr
[ehdr
->e_phnum
]; ++ph
)
1617 if (ph
->p_type
== PT_NOTE
&& ph
->p_filesz
>= 32 && ph
->p_align
>= 4)
1619 ElfW(Addr
) size
= ph
->p_filesz
;
1620 /* NB: Some PT_NOTE segment may have alignment value of 0
1621 or 1. gABI specifies that PT_NOTE segments should be
1622 aligned to 4 bytes in 32-bit objects and to 8 bytes in
1623 64-bit objects. As a Linux extension, we also support
1624 4 byte alignment in 64-bit objects. If p_align is less
1625 than 4, we treate alignment as 4 bytes since some note
1626 segments have 0 or 1 byte alignment. */
1627 ElfW(Addr
) align
= ph
->p_align
;
1630 else if (align
!= 4 && align
!= 8)
1633 if (ph
->p_offset
+ size
<= (size_t) fbp
->len
)
1634 abi_note
= (void *) (fbp
->buf
+ ph
->p_offset
);
1637 /* Note: __libc_use_alloca is not usable here, because
1638 thread info may not have been set up yet. */
1639 if (size
< __MAX_ALLOCA_CUTOFF
)
1640 abi_note
= alloca (size
);
1643 /* There could be multiple PT_NOTEs. */
1644 abi_note_malloced
= realloc (abi_note_malloced
, size
);
1645 if (abi_note_malloced
== NULL
)
1648 abi_note
= abi_note_malloced
;
1650 __lseek (fd
, ph
->p_offset
, SEEK_SET
);
1651 if (__libc_read (fd
, (void *) abi_note
, size
) != size
)
1653 free (abi_note_malloced
);
1658 while (memcmp (abi_note
, &expected_note
, sizeof (expected_note
)))
1660 ElfW(Addr
) note_size
1661 = ELF_NOTE_NEXT_OFFSET (abi_note
[0], abi_note
[1],
1664 if (size
- 32 < note_size
)
1670 abi_note
= (void *) abi_note
+ note_size
;
1676 osversion
= (abi_note
[5] & 0xff) * 65536
1677 + (abi_note
[6] & 0xff) * 256
1678 + (abi_note
[7] & 0xff);
1679 if (abi_note
[4] != __ABI_TAG_OS
1680 || (GLRO(dl_osversion
) && GLRO(dl_osversion
) < osversion
))
1684 __set_errno (ENOENT
);
1690 free (abi_note_malloced
);
1696 /* Try to open NAME in one of the directories in *DIRSP.
1697 Return the fd, or -1. If successful, fill in *REALNAME
1698 with the malloc'd full directory name. If it turns out
1699 that none of the directories in *DIRSP exists, *DIRSP is
1700 replaced with (void *) -1, and the old value is free()d
1701 if MAY_FREE_DIRS is true. */
1704 open_path (const char *name
, size_t namelen
, int mode
,
1705 struct r_search_path_struct
*sps
, char **realname
,
1706 struct filebuf
*fbp
, struct link_map
*loader
, int whatcode
,
1707 bool *found_other_class
)
1709 struct r_search_path_elem
**dirs
= sps
->dirs
;
1712 const char *current_what
= NULL
;
1715 if (__glibc_unlikely (dirs
== NULL
))
1716 /* We're called before _dl_init_paths when loading the main executable
1717 given on the command line when rtld is run directly. */
1720 buf
= alloca (max_dirnamelen
+ max_capstrlen
+ namelen
);
1723 struct r_search_path_elem
*this_dir
= *dirs
;
1730 /* If we are debugging the search for libraries print the path
1731 now if it hasn't happened now. */
1732 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_LIBS
)
1733 && current_what
!= this_dir
->what
)
1735 current_what
= this_dir
->what
;
1736 print_search_path (dirs
, current_what
, this_dir
->where
);
1739 edp
= (char *) __mempcpy (buf
, this_dir
->dirname
, this_dir
->dirnamelen
);
1740 for (cnt
= 0; fd
== -1 && cnt
< ncapstr
; ++cnt
)
1742 /* Skip this directory if we know it does not exist. */
1743 if (this_dir
->status
[cnt
] == nonexisting
)
1747 ((char *) __mempcpy (__mempcpy (edp
, capstr
[cnt
].str
,
1752 /* Print name we try if this is wanted. */
1753 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_LIBS
))
1754 _dl_debug_printf (" trying file=%s\n", buf
);
1756 fd
= open_verify (buf
, -1, fbp
, loader
, whatcode
, mode
,
1757 found_other_class
, false);
1758 if (this_dir
->status
[cnt
] == unknown
)
1761 this_dir
->status
[cnt
] = existing
;
1762 /* Do not update the directory information when loading
1763 auditing code. We must try to disturb the program as
1764 little as possible. */
1765 else if (loader
== NULL
1766 || GL(dl_ns
)[loader
->l_ns
]._ns_loaded
->l_auditing
== 0)
1768 /* We failed to open machine dependent library. Let's
1769 test whether there is any directory at all. */
1772 buf
[buflen
- namelen
- 1] = '\0';
1774 if (__xstat64 (_STAT_VER
, buf
, &st
) != 0
1775 || ! S_ISDIR (st
.st_mode
))
1776 /* The directory does not exist or it is no directory. */
1777 this_dir
->status
[cnt
] = nonexisting
;
1779 this_dir
->status
[cnt
] = existing
;
1783 /* Remember whether we found any existing directory. */
1784 here_any
|= this_dir
->status
[cnt
] != nonexisting
;
1786 if (fd
!= -1 && __glibc_unlikely (mode
& __RTLD_SECURE
)
1787 && __libc_enable_secure
)
1789 /* This is an extra security effort to make sure nobody can
1790 preload broken shared objects which are in the trusted
1791 directories and so exploit the bugs. */
1794 if (__fxstat64 (_STAT_VER
, fd
, &st
) != 0
1795 || (st
.st_mode
& S_ISUID
) == 0)
1797 /* The shared object cannot be tested for being SUID
1798 or this bit is not set. In this case we must not
1802 /* We simply ignore the file, signal this by setting
1803 the error value which would have been set by `open'. */
1811 *realname
= (char *) malloc (buflen
);
1812 if (*realname
!= NULL
)
1814 memcpy (*realname
, buf
, buflen
);
1819 /* No memory for the name, we certainly won't be able
1820 to load and link it. */
1825 if (here_any
&& (err
= errno
) != ENOENT
&& err
!= EACCES
)
1826 /* The file exists and is readable, but something went wrong. */
1829 /* Remember whether we found anything. */
1832 while (*++dirs
!= NULL
);
1834 /* Remove the whole path if none of the directories exists. */
1835 if (__glibc_unlikely (! any
))
1837 /* Paths which were allocated using the minimal malloc() in ld.so
1838 must not be freed using the general free() in libc. */
1842 /* rtld_search_dirs and env_path_list are attribute_relro, therefore
1843 avoid writing into it. */
1844 if (sps
!= &rtld_search_dirs
&& sps
!= &env_path_list
)
1845 sps
->dirs
= (void *) -1;
1851 /* Map in the shared object file NAME. */
1854 _dl_map_object (struct link_map
*loader
, const char *name
,
1855 int type
, int trace_mode
, int mode
, Lmid_t nsid
)
1858 const char *origname
= NULL
;
1865 assert (nsid
< GL(dl_nns
));
1867 /* Look for this name among those already loaded. */
1868 for (l
= GL(dl_ns
)[nsid
]._ns_loaded
; l
; l
= l
->l_next
)
1870 /* If the requested name matches the soname of a loaded object,
1871 use that object. Elide this check for names that have not
1873 if (__glibc_unlikely ((l
->l_faked
| l
->l_removed
) != 0))
1875 if (!_dl_name_match_p (name
, l
))
1879 if (__glibc_likely (l
->l_soname_added
)
1880 || l
->l_info
[DT_SONAME
] == NULL
)
1883 soname
= ((const char *) D_PTR (l
, l_info
[DT_STRTAB
])
1884 + l
->l_info
[DT_SONAME
]->d_un
.d_val
);
1885 if (strcmp (name
, soname
) != 0)
1888 /* We have a match on a new name -- cache it. */
1889 add_name_to_object (l
, soname
);
1890 l
->l_soname_added
= 1;
1893 /* We have a match. */
1897 /* Display information if we are debugging. */
1898 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_FILES
)
1900 _dl_debug_printf ((mode
& __RTLD_CALLMAP
) == 0
1901 ? "\nfile=%s [%lu]; needed by %s [%lu]\n"
1902 : "\nfile=%s [%lu]; dynamically loaded by %s [%lu]\n",
1903 name
, nsid
, DSO_FILENAME (loader
->l_name
), loader
->l_ns
);
1906 /* Give the auditing libraries a chance to change the name before we
1908 if (__glibc_unlikely (GLRO(dl_naudit
) > 0)
1909 && (loader
== NULL
|| loader
->l_auditing
== 0))
1911 struct audit_ifaces
*afct
= GLRO(dl_audit
);
1912 for (unsigned int cnt
= 0; cnt
< GLRO(dl_naudit
); ++cnt
)
1914 if (afct
->objsearch
!= NULL
)
1916 const char *before
= name
;
1917 name
= afct
->objsearch (name
, &loader
->l_audit
[cnt
].cookie
,
1921 /* Do not try anything further. */
1925 if (before
!= name
&& strcmp (before
, name
) != 0)
1927 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_FILES
))
1928 _dl_debug_printf ("audit changed filename %s -> %s\n",
1931 if (origname
== NULL
)
1941 /* Will be true if we found a DSO which is of the other ELF class. */
1942 bool found_other_class
= false;
1944 if (strchr (name
, '/') == NULL
)
1946 /* Search for NAME in several places. */
1948 size_t namelen
= strlen (name
) + 1;
1950 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_LIBS
))
1951 _dl_debug_printf ("find library=%s [%lu]; searching\n", name
, nsid
);
1955 /* When the object has the RUNPATH information we don't use any
1957 if (loader
== NULL
|| loader
->l_info
[DT_RUNPATH
] == NULL
)
1959 /* This is the executable's map (if there is one). Make sure that
1960 we do not look at it twice. */
1961 struct link_map
*main_map
= GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
;
1962 bool did_main_map
= false;
1964 /* First try the DT_RPATH of the dependent object that caused NAME
1965 to be loaded. Then that object's dependent, and on up. */
1966 for (l
= loader
; l
; l
= l
->l_loader
)
1967 if (cache_rpath (l
, &l
->l_rpath_dirs
, DT_RPATH
, "RPATH"))
1969 fd
= open_path (name
, namelen
, mode
,
1971 &realname
, &fb
, loader
, LA_SER_RUNPATH
,
1972 &found_other_class
);
1976 did_main_map
|= l
== main_map
;
1979 /* If dynamically linked, try the DT_RPATH of the executable
1980 itself. NB: we do this for lookups in any namespace. */
1981 if (fd
== -1 && !did_main_map
1982 && main_map
!= NULL
&& main_map
->l_type
!= lt_loaded
1983 && cache_rpath (main_map
, &main_map
->l_rpath_dirs
, DT_RPATH
,
1985 fd
= open_path (name
, namelen
, mode
,
1986 &main_map
->l_rpath_dirs
,
1987 &realname
, &fb
, loader
?: main_map
, LA_SER_RUNPATH
,
1988 &found_other_class
);
1991 /* Try the LD_LIBRARY_PATH environment variable. */
1992 if (fd
== -1 && env_path_list
.dirs
!= (void *) -1)
1993 fd
= open_path (name
, namelen
, mode
, &env_path_list
,
1995 loader
?: GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
,
1996 LA_SER_LIBPATH
, &found_other_class
);
1998 /* Look at the RUNPATH information for this binary. */
1999 if (fd
== -1 && loader
!= NULL
2000 && cache_rpath (loader
, &loader
->l_runpath_dirs
,
2001 DT_RUNPATH
, "RUNPATH"))
2002 fd
= open_path (name
, namelen
, mode
,
2003 &loader
->l_runpath_dirs
, &realname
, &fb
, loader
,
2004 LA_SER_RUNPATH
, &found_other_class
);
2008 realname
= _dl_sysdep_open_object (name
, namelen
, &fd
);
2009 if (realname
!= NULL
)
2011 fd
= open_verify (realname
, fd
,
2012 &fb
, loader
?: GL(dl_ns
)[nsid
]._ns_loaded
,
2013 LA_SER_CONFIG
, mode
, &found_other_class
,
2022 && (__glibc_likely ((mode
& __RTLD_SECURE
) == 0)
2023 || ! __libc_enable_secure
)
2024 && __glibc_likely (GLRO(dl_inhibit_cache
) == 0))
2026 /* Check the list of libraries in the file /etc/ld.so.cache,
2027 for compatibility with Linux's ldconfig program. */
2028 char *cached
= _dl_load_cache_lookup (name
);
2032 // XXX Correct to unconditionally default to namespace 0?
2034 ?: GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
2040 /* If the loader has the DF_1_NODEFLIB flag set we must not
2041 use a cache entry from any of these directories. */
2042 if (__glibc_unlikely (l
->l_flags_1
& DF_1_NODEFLIB
))
2044 const char *dirp
= system_dirs
;
2045 unsigned int cnt
= 0;
2049 if (memcmp (cached
, dirp
, system_dirs_len
[cnt
]) == 0)
2051 /* The prefix matches. Don't use the entry. */
2057 dirp
+= system_dirs_len
[cnt
] + 1;
2060 while (cnt
< nsystem_dirs_len
);
2065 fd
= open_verify (cached
, -1,
2066 &fb
, loader
?: GL(dl_ns
)[nsid
]._ns_loaded
,
2067 LA_SER_CONFIG
, mode
, &found_other_class
,
2069 if (__glibc_likely (fd
!= -1))
2078 /* Finally, try the default path. */
2080 && ((l
= loader
?: GL(dl_ns
)[nsid
]._ns_loaded
) == NULL
2081 || __glibc_likely (!(l
->l_flags_1
& DF_1_NODEFLIB
)))
2082 && rtld_search_dirs
.dirs
!= (void *) -1)
2083 fd
= open_path (name
, namelen
, mode
, &rtld_search_dirs
,
2084 &realname
, &fb
, l
, LA_SER_DEFAULT
, &found_other_class
);
2086 /* Add another newline when we are tracing the library loading. */
2087 if (__glibc_unlikely (GLRO(dl_debug_mask
) & DL_DEBUG_LIBS
))
2088 _dl_debug_printf ("\n");
2092 /* The path may contain dynamic string tokens. */
2094 ? expand_dynamic_string_token (loader
, name
)
2096 if (realname
== NULL
)
2100 fd
= open_verify (realname
, -1, &fb
,
2101 loader
?: GL(dl_ns
)[nsid
]._ns_loaded
, 0, mode
,
2102 &found_other_class
, true);
2103 if (__glibc_unlikely (fd
== -1))
2111 /* In case the LOADER information has only been provided to get to
2112 the appropriate RUNPATH/RPATH information we do not need it
2114 if (mode
& __RTLD_CALLMAP
)
2117 if (__glibc_unlikely (fd
== -1))
2120 && __glibc_likely ((GLRO(dl_debug_mask
) & DL_DEBUG_PRELINK
) == 0))
2122 /* We haven't found an appropriate library. But since we
2123 are only interested in the list of libraries this isn't
2124 so severe. Fake an entry with all the information we
2126 static const Elf_Symndx dummy_bucket
= STN_UNDEF
;
2128 /* Allocate a new object map. */
2129 if ((name_copy
= __strdup (name
)) == NULL
2130 || (l
= _dl_new_object (name_copy
, name
, type
, loader
,
2131 mode
, nsid
)) == NULL
)
2134 _dl_signal_error (ENOMEM
, name
, NULL
,
2135 N_("cannot create shared object descriptor"));
2137 /* Signal that this is a faked entry. */
2139 /* Since the descriptor is initialized with zero we do not
2141 l->l_reserved = 0; */
2142 l
->l_buckets
= &dummy_bucket
;
2146 /* Enter the object in the object list. */
2147 _dl_add_to_namespace_list (l
, nsid
);
2151 else if (found_other_class
)
2152 _dl_signal_error (0, name
, NULL
,
2153 ELFW(CLASS
) == ELFCLASS32
2154 ? N_("wrong ELF class: ELFCLASS64")
2155 : N_("wrong ELF class: ELFCLASS32"));
2157 _dl_signal_error (errno
, name
, NULL
,
2158 N_("cannot open shared object file"));
2161 void *stack_end
= __libc_stack_end
;
2162 return _dl_map_object_from_fd (name
, origname
, fd
, &fb
, realname
, loader
,
2163 type
, mode
, &stack_end
, nsid
);
2166 struct add_path_state
2175 add_path (struct add_path_state
*p
, const struct r_search_path_struct
*sps
,
2178 if (sps
->dirs
!= (void *) -1)
2180 struct r_search_path_elem
**dirs
= sps
->dirs
;
2183 const struct r_search_path_elem
*const r
= *dirs
++;
2187 p
->si
->dls_size
+= MAX (2, r
->dirnamelen
);
2191 Dl_serpath
*const sp
= &p
->si
->dls_serpath
[p
->idx
++];
2192 sp
->dls_name
= p
->allocptr
;
2193 if (r
->dirnamelen
< 2)
2194 *p
->allocptr
++ = r
->dirnamelen
? '/' : '.';
2196 p
->allocptr
= __mempcpy (p
->allocptr
,
2197 r
->dirname
, r
->dirnamelen
- 1);
2198 *p
->allocptr
++ = '\0';
2199 sp
->dls_flags
= flags
;
2202 while (*dirs
!= NULL
);
2207 _dl_rtld_di_serinfo (struct link_map
*loader
, Dl_serinfo
*si
, bool counting
)
2215 struct add_path_state p
=
2217 .counting
= counting
,
2220 .allocptr
= (char *) &si
->dls_serpath
[si
->dls_cnt
]
2223 # define add_path(p, sps, flags) add_path(p, sps, 0) /* XXX */
2225 /* When the object has the RUNPATH information we don't use any RPATHs. */
2226 if (loader
->l_info
[DT_RUNPATH
] == NULL
)
2228 /* First try the DT_RPATH of the dependent object that caused NAME
2229 to be loaded. Then that object's dependent, and on up. */
2231 struct link_map
*l
= loader
;
2234 if (cache_rpath (l
, &l
->l_rpath_dirs
, DT_RPATH
, "RPATH"))
2235 add_path (&p
, &l
->l_rpath_dirs
, XXX_RPATH
);
2240 /* If dynamically linked, try the DT_RPATH of the executable itself. */
2241 if (loader
->l_ns
== LM_ID_BASE
)
2243 l
= GL(dl_ns
)[LM_ID_BASE
]._ns_loaded
;
2244 if (l
!= NULL
&& l
->l_type
!= lt_loaded
&& l
!= loader
)
2245 if (cache_rpath (l
, &l
->l_rpath_dirs
, DT_RPATH
, "RPATH"))
2246 add_path (&p
, &l
->l_rpath_dirs
, XXX_RPATH
);
2250 /* Try the LD_LIBRARY_PATH environment variable. */
2251 add_path (&p
, &env_path_list
, XXX_ENV
);
2253 /* Look at the RUNPATH information for this binary. */
2254 if (cache_rpath (loader
, &loader
->l_runpath_dirs
, DT_RUNPATH
, "RUNPATH"))
2255 add_path (&p
, &loader
->l_runpath_dirs
, XXX_RUNPATH
);
2258 Here is where ld.so.cache gets checked, but we don't have
2259 a way to indicate that in the results for Dl_serinfo. */
2261 /* Finally, try the default path. */
2262 if (!(loader
->l_flags_1
& DF_1_NODEFLIB
))
2263 add_path (&p
, &rtld_search_dirs
, XXX_default
);
2266 /* Count the struct size before the string area, which we didn't
2267 know before we completed dls_cnt. */
2268 si
->dls_size
+= (char *) &si
->dls_serpath
[si
->dls_cnt
] - (char *) si
;