1 /* Map in a shared object's segments from the file.
2 Copyright (C) 1995-2007, 2009, 2010, 2011 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
29 #include <bits/wordsize.h>
31 #include <sys/param.h>
33 #include <sys/types.h>
34 #include "dynamic-link.h"
36 #include <stackinfo.h>
42 /* On some systems, no flag bits are given to specify file mapping. */
47 /* The right way to map in the shared library files is MAP_COPY, which
48 makes a virtual copy of the data at the time of the mmap call; this
49 guarantees the mapped pages will be consistent even if the file is
50 overwritten. Some losing VM systems like Linux's lack MAP_COPY. All we
51 get is MAP_PRIVATE, which copies each page when it is modified; this
52 means if the file is overwritten, we may at some point get some pages
53 from the new version after starting with pages from the old version.
55 To make up for the lack and avoid the overwriting problem,
56 what Linux does have is MAP_DENYWRITE. This prevents anyone
57 from modifying the file while we have it mapped. */
60 # define MAP_COPY (MAP_PRIVATE | MAP_DENYWRITE)
62 # define MAP_COPY MAP_PRIVATE
66 /* Some systems link their relocatable objects for another base address
67 than 0. We want to know the base address for these such that we can
68 subtract this address from the segment addresses during mapping.
69 This results in a more efficient address space usage. Defaults to
70 zero for almost all systems. */
72 # define MAP_BASE_ADDR(l) 0
77 #if BYTE_ORDER == BIG_ENDIAN
78 # define byteorder ELFDATA2MSB
79 #elif BYTE_ORDER == LITTLE_ENDIAN
80 # define byteorder ELFDATA2LSB
82 # error "Unknown BYTE_ORDER " BYTE_ORDER
83 # define byteorder ELFDATANONE
86 #define STRING(x) __STRING (x)
88 /* Handle situations where we have a preferred location in memory for
89 the shared objects. */
90 #ifdef ELF_PREFERRED_ADDRESS_DATA
91 ELF_PREFERRED_ADDRESS_DATA;
93 #ifndef ELF_PREFERRED_ADDRESS
94 # define ELF_PREFERRED_ADDRESS(loader, maplength, mapstartpref) (mapstartpref)
96 #ifndef ELF_FIXED_ADDRESS
97 # define ELF_FIXED_ADDRESS(loader, mapstart) ((void) 0)
101 int __stack_prot attribute_hidden attribute_relro
102 #if _STACK_GROWS_DOWN && defined PROT_GROWSDOWN
104 #elif _STACK_GROWS_UP && defined PROT_GROWSUP
111 /* Type for the buffer we put the ELF header and hopefully the program
112 header. This buffer does not really have to be too large. In most
113 cases the program header follows the ELF header directly. If this
114 is not the case all bets are off and we can make the header
115 arbitrarily large and still won't get it read. This means the only
116 question is how large are the ELF and program header combined. The
117 ELF header 32-bit files is 52 bytes long and in 64-bit files is 64
118 bytes long. Each program header entry is again 32 and 56 bytes
119 long respectively. I.e., even with a file which has 10 program
120 header entries we only have to read 372B/624B respectively. Add to
121 this a bit of margin for program notes and reading 512B and 832B
122 for 32-bit and 64-bit files respecitvely is enough. If this
123 heuristic should really fail for some file the code in
124 `_dl_map_object_from_fd' knows how to recover. */
129 # define FILEBUF_SIZE 512
131 # define FILEBUF_SIZE 832
133 char buf[FILEBUF_SIZE] __attribute__ ((aligned (__alignof (ElfW(Ehdr)))));
136 /* This is the decomposed LD_LIBRARY_PATH search path. */
137 static struct r_search_path_struct env_path_list attribute_relro;
139 /* List of the hardware capabilities we might end up using. */
140 static const struct r_strlenpair *capstr attribute_relro;
141 static size_t ncapstr attribute_relro;
142 static size_t max_capstrlen attribute_relro;
145 /* Get the generated information about the trusted directories. */
146 #include "trusted-dirs.h"
148 static const char system_dirs[] = SYSTEM_DIRS;
149 static const size_t system_dirs_len[] =
153 #define nsystem_dirs_len \
154 (sizeof (system_dirs_len) / sizeof (system_dirs_len[0]))
157 /* Local version of `strdup' function. */
159 local_strdup (const char *s)
161 size_t len = strlen (s) + 1;
162 void *new = malloc (len);
167 return (char *) memcpy (new, s, len);
172 is_trusted_path (const char *path, size_t len)
174 const char *trun = system_dirs;
176 for (size_t idx = 0; idx < nsystem_dirs_len; ++idx)
178 if (len == system_dirs_len[idx] && memcmp (trun, path, len) == 0)
182 trun += system_dirs_len[idx] + 1;
190 is_trusted_path_normalize (const char *path, size_t len)
201 char *npath = (char *) alloca (len + 2);
203 while (*path != '\0')
209 if (path[2] == '.' && (path[3] == '/' || path[3] == '\0'))
211 while (wnp > npath && *--wnp != '/')
216 else if (path[2] == '/' || path[2] == '\0')
223 if (wnp > npath && wnp[-1] == '/')
233 if (wnp == npath || wnp[-1] != '/')
236 const char *trun = system_dirs;
238 for (size_t idx = 0; idx < nsystem_dirs_len; ++idx)
240 if (wnp - npath >= system_dirs_len[idx]
241 && memcmp (trun, npath, system_dirs_len[idx]) == 0)
245 trun += system_dirs_len[idx] + 1;
253 is_dst (const char *start, const char *name, const char *str,
254 int is_path, int secure)
257 bool is_curly = false;
266 while (name[len] == str[len] && name[len] != '\0')
271 if (name[len] != '}')
274 /* Point again at the beginning of the name. */
276 /* Skip over closing curly brace and adjust for the --name. */
279 else if (name[len] != '\0' && name[len] != '/'
280 && (!is_path || name[len] != ':'))
283 if (__builtin_expect (secure, 0)
284 && ((name[len] != '\0' && name[len] != '/'
285 && (!is_path || name[len] != ':'))
286 || (name != start + 1 && (!is_path || name[-2] != ':'))))
294 _dl_dst_count (const char *name, int is_path)
296 const char *const start = name;
303 /* $ORIGIN is not expanded for SUID/GUID programs (except if it
304 is $ORIGIN alone) and it must always appear first in path. */
306 if ((len = is_dst (start, name, "ORIGIN", is_path,
307 INTUSE(__libc_enable_secure))) != 0
308 || (len = is_dst (start, name, "PLATFORM", is_path, 0)) != 0
309 || (len = is_dst (start, name, "LIB", is_path, 0)) != 0)
312 name = strchr (name + len, '$');
314 while (name != NULL);
321 _dl_dst_substitute (struct link_map *l, const char *name, char *result,
324 const char *const start = name;
326 /* Now fill the result path. While copying over the string we keep
327 track of the start of the last path element. When we come accross
328 a DST we copy over the value or (if the value is not available)
329 leave the entire path element out. */
331 char *last_elem = result;
332 bool check_for_trusted = false;
336 if (__builtin_expect (*name == '$', 0))
338 const char *repl = NULL;
342 if ((len = is_dst (start, name, "ORIGIN", is_path,
343 INTUSE(__libc_enable_secure))) != 0)
347 repl = _dl_get_origin ();
352 check_for_trusted = (INTUSE(__libc_enable_secure)
353 && l->l_type == lt_executable);
355 else if ((len = is_dst (start, name, "PLATFORM", is_path, 0)) != 0)
356 repl = GLRO(dl_platform);
357 else if ((len = is_dst (start, name, "LIB", is_path, 0)) != 0)
360 if (repl != NULL && repl != (const char *) -1)
362 wp = __stpcpy (wp, repl);
367 /* We cannot use this path element, the value of the
368 replacement is unknown. */
371 while (*name != '\0' && (!is_path || *name != ':'))
373 /* Also skip following colon if this is the first rpath
374 element, but keep an empty element at the end. */
375 if (wp == result && is_path && *name == ':' && name[1] != '\0')
379 /* No DST we recognize. */
385 if (is_path && *name == ':')
387 /* In SUID/SGID programs, after $ORIGIN expansion the
388 normalized path must be rooted in one of the trusted
390 if (__builtin_expect (check_for_trusted, false)
391 && !is_trusted_path_normalize (last_elem, wp - last_elem))
396 check_for_trusted = false;
400 while (*name != '\0');
402 /* In SUID/SGID programs, after $ORIGIN expansion the normalized
403 path must be rooted in one of the trusted directories. */
404 if (__builtin_expect (check_for_trusted, false)
405 && !is_trusted_path_normalize (last_elem, wp - last_elem))
414 /* Return copy of argument with all recognized dynamic string tokens
415 ($ORIGIN and $PLATFORM for now) replaced. On some platforms it
416 might not be possible to determine the path from which the object
417 belonging to the map is loaded. In this case the path element
418 containing $ORIGIN is left out. */
420 expand_dynamic_string_token (struct link_map *l, const char *s, int is_path)
422 /* We make two runs over the string. First we determine how large the
423 resulting string is and then we copy it over. Since this is no
424 frequently executed operation we are looking here not for performance
425 but rather for code size. */
430 /* Determine the number of DST elements. */
431 cnt = DL_DST_COUNT (s, is_path);
433 /* If we do not have to replace anything simply copy the string. */
434 if (__builtin_expect (cnt, 0) == 0)
435 return local_strdup (s);
437 /* Determine the length of the substituted string. */
438 total = DL_DST_REQUIRED (l, s, strlen (s), cnt);
440 /* Allocate the necessary memory. */
441 result = (char *) malloc (total + 1);
445 return _dl_dst_substitute (l, s, result, is_path);
449 /* Add `name' to the list of names for a particular shared object.
450 `name' is expected to have been allocated with malloc and will
451 be freed if the shared object already has this name.
452 Returns false if the object already had this name. */
455 add_name_to_object (struct link_map *l, const char *name)
457 struct libname_list *lnp, *lastp;
458 struct libname_list *newname;
462 for (lnp = l->l_libname; lnp != NULL; lastp = lnp, lnp = lnp->next)
463 if (strcmp (name, lnp->name) == 0)
466 name_len = strlen (name) + 1;
467 newname = (struct libname_list *) malloc (sizeof *newname + name_len);
470 /* No more memory. */
471 _dl_signal_error (ENOMEM, name, NULL, N_("cannot allocate name record"));
474 /* The object should have a libname set from _dl_new_object. */
475 assert (lastp != NULL);
477 newname->name = memcpy (newname + 1, name, name_len);
478 newname->next = NULL;
479 newname->dont_free = 0;
480 lastp->next = newname;
483 /* Standard search directories. */
484 static struct r_search_path_struct rtld_search_dirs attribute_relro;
486 static size_t max_dirnamelen;
488 static struct r_search_path_elem **
489 fillin_rpath (char *rpath, struct r_search_path_elem **result, const char *sep,
490 int check_trusted, const char *what, const char *where)
495 while ((cp = __strsep (&rpath, sep)) != NULL)
497 struct r_search_path_elem *dirp;
498 size_t len = strlen (cp);
500 /* `strsep' can pass an empty string. This has to be
501 interpreted as `use the current directory'. */
504 static const char curwd[] = "./";
508 /* Remove trailing slashes (except for "/"). */
509 while (len > 1 && cp[len - 1] == '/')
512 /* Now add one if there is none so far. */
513 if (len > 0 && cp[len - 1] != '/')
516 /* Make sure we don't use untrusted directories if we run SUID. */
517 if (__builtin_expect (check_trusted, 0) && !is_trusted_path (cp, len))
520 /* See if this directory is already known. */
521 for (dirp = GL(dl_all_dirs); dirp != NULL; dirp = dirp->next)
522 if (dirp->dirnamelen == len && memcmp (cp, dirp->dirname, len) == 0)
527 /* It is available, see whether it's on our own list. */
529 for (cnt = 0; cnt < nelems; ++cnt)
530 if (result[cnt] == dirp)
534 result[nelems++] = dirp;
539 enum r_dir_status init_val;
540 size_t where_len = where ? strlen (where) + 1 : 0;
542 /* It's a new directory. Create an entry and add it. */
543 dirp = (struct r_search_path_elem *)
544 malloc (sizeof (*dirp) + ncapstr * sizeof (enum r_dir_status)
545 + where_len + len + 1);
547 _dl_signal_error (ENOMEM, NULL, NULL,
548 N_("cannot create cache for search path"));
550 dirp->dirname = ((char *) dirp + sizeof (*dirp)
551 + ncapstr * sizeof (enum r_dir_status));
552 *((char *) __mempcpy ((char *) dirp->dirname, cp, len)) = '\0';
553 dirp->dirnamelen = len;
555 if (len > max_dirnamelen)
556 max_dirnamelen = len;
558 /* We have to make sure all the relative directories are
559 never ignored. The current directory might change and
560 all our saved information would be void. */
561 init_val = cp[0] != '/' ? existing : unknown;
562 for (cnt = 0; cnt < ncapstr; ++cnt)
563 dirp->status[cnt] = init_val;
566 if (__builtin_expect (where != NULL, 1))
567 dirp->where = memcpy ((char *) dirp + sizeof (*dirp) + len + 1
568 + (ncapstr * sizeof (enum r_dir_status)),
573 dirp->next = GL(dl_all_dirs);
574 GL(dl_all_dirs) = dirp;
576 /* Put it in the result array. */
577 result[nelems++] = dirp;
581 /* Terminate the array. */
582 result[nelems] = NULL;
590 decompose_rpath (struct r_search_path_struct *sps,
591 const char *rpath, struct link_map *l, const char *what)
593 /* Make a copy we can work with. */
594 const char *where = l->l_name;
597 struct r_search_path_elem **result;
599 /* Initialize to please the compiler. */
600 const char *errstring = NULL;
602 /* First see whether we must forget the RUNPATH and RPATH from this
604 if (__builtin_expect (GLRO(dl_inhibit_rpath) != NULL, 0)
605 && !INTUSE(__libc_enable_secure))
607 const char *inhp = GLRO(dl_inhibit_rpath);
611 const char *wp = where;
613 while (*inhp == *wp && *wp != '\0')
619 if (*wp == '\0' && (*inhp == '\0' || *inhp == ':'))
621 /* This object is on the list of objects for which the
622 RUNPATH and RPATH must not be used. */
623 sps->dirs = (void *) -1;
627 while (*inhp != '\0')
631 while (*inhp != '\0');
634 /* Make a writable copy. At the same time expand possible dynamic
636 copy = expand_dynamic_string_token (l, rpath, 1);
639 errstring = N_("cannot create RUNPATH/RPATH copy");
643 /* Ignore empty rpaths. */
647 sps->dirs = (struct r_search_path_elem **) -1;
651 /* Count the number of necessary elements in the result array. */
653 for (cp = copy; *cp != '\0'; ++cp)
657 /* Allocate room for the result. NELEMS + 1 is an upper limit for the
658 number of necessary entries. */
659 result = (struct r_search_path_elem **) malloc ((nelems + 1 + 1)
664 errstring = N_("cannot create cache for search path");
666 _dl_signal_error (ENOMEM, NULL, NULL, errstring);
669 fillin_rpath (copy, result, ":", 0, what, where);
671 /* Free the copied RPATH string. `fillin_rpath' make own copies if
676 /* The caller will change this value if we haven't used a real malloc. */
681 /* Make sure cached path information is stored in *SP
682 and return true if there are any paths to search there. */
684 cache_rpath (struct link_map *l,
685 struct r_search_path_struct *sp,
689 if (sp->dirs == (void *) -1)
692 if (sp->dirs != NULL)
695 if (l->l_info[tag] == NULL)
697 /* There is no path. */
698 sp->dirs = (void *) -1;
702 /* Make sure the cache information is available. */
703 return decompose_rpath (sp, (const char *) (D_PTR (l, l_info[DT_STRTAB])
704 + l->l_info[tag]->d_un.d_val),
711 _dl_init_paths (const char *llp)
715 struct r_search_path_elem *pelem, **aelem;
720 /* Initialize to please the compiler. */
721 const char *errstring = NULL;
723 /* Fill in the information about the application's RPATH and the
724 directories addressed by the LD_LIBRARY_PATH environment variable. */
726 /* Get the capabilities. */
727 capstr = _dl_important_hwcaps (GLRO(dl_platform), GLRO(dl_platformlen),
728 &ncapstr, &max_capstrlen);
730 /* First set up the rest of the default search directory entries. */
731 aelem = rtld_search_dirs.dirs = (struct r_search_path_elem **)
732 malloc ((nsystem_dirs_len + 1) * sizeof (struct r_search_path_elem *));
733 if (rtld_search_dirs.dirs == NULL)
735 errstring = N_("cannot create search path array");
737 _dl_signal_error (ENOMEM, NULL, NULL, errstring);
740 round_size = ((2 * sizeof (struct r_search_path_elem) - 1
741 + ncapstr * sizeof (enum r_dir_status))
742 / sizeof (struct r_search_path_elem));
744 rtld_search_dirs.dirs[0] = (struct r_search_path_elem *)
745 malloc ((sizeof (system_dirs) / sizeof (system_dirs[0]))
746 * round_size * sizeof (struct r_search_path_elem));
747 if (rtld_search_dirs.dirs[0] == NULL)
749 errstring = N_("cannot create cache for search path");
753 rtld_search_dirs.malloced = 0;
754 pelem = GL(dl_all_dirs) = rtld_search_dirs.dirs[0];
764 pelem->what = "system search path";
767 pelem->dirname = strp;
768 pelem->dirnamelen = system_dirs_len[idx];
769 strp += system_dirs_len[idx] + 1;
771 /* System paths must be absolute. */
772 assert (pelem->dirname[0] == '/');
773 for (cnt = 0; cnt < ncapstr; ++cnt)
774 pelem->status[cnt] = unknown;
776 pelem->next = (++idx == nsystem_dirs_len ? NULL : (pelem + round_size));
780 while (idx < nsystem_dirs_len);
782 max_dirnamelen = SYSTEM_DIRS_MAX_LEN;
786 /* This points to the map of the main object. */
787 l = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
790 assert (l->l_type != lt_loaded);
792 if (l->l_info[DT_RUNPATH])
794 /* Allocate room for the search path and fill in information
796 decompose_rpath (&l->l_runpath_dirs,
797 (const void *) (D_PTR (l, l_info[DT_STRTAB])
798 + l->l_info[DT_RUNPATH]->d_un.d_val),
801 /* The RPATH is ignored. */
802 l->l_rpath_dirs.dirs = (void *) -1;
806 l->l_runpath_dirs.dirs = (void *) -1;
808 if (l->l_info[DT_RPATH])
810 /* Allocate room for the search path and fill in information
812 decompose_rpath (&l->l_rpath_dirs,
813 (const void *) (D_PTR (l, l_info[DT_STRTAB])
814 + l->l_info[DT_RPATH]->d_un.d_val),
816 l->l_rpath_dirs.malloced = 0;
819 l->l_rpath_dirs.dirs = (void *) -1;
824 if (llp != NULL && *llp != '\0')
827 const char *cp = llp;
832 size_t cnt = DL_DST_COUNT (llp, 1);
833 if (__builtin_expect (cnt == 0, 1))
834 llp_tmp = strdupa (llp);
837 /* Determine the length of the substituted string. */
838 size_t total = DL_DST_REQUIRED (l, llp, strlen (llp), cnt);
840 /* Allocate the necessary memory. */
841 llp_tmp = (char *) alloca (total + 1);
842 llp_tmp = _dl_dst_substitute (l, llp, llp_tmp, 1);
845 llp_tmp = strdupa (llp);
848 /* Decompose the LD_LIBRARY_PATH contents. First determine how many
853 if (*cp == ':' || *cp == ';')
858 env_path_list.dirs = (struct r_search_path_elem **)
859 malloc ((nllp + 1) * sizeof (struct r_search_path_elem *));
860 if (env_path_list.dirs == NULL)
862 errstring = N_("cannot create cache for search path");
866 (void) fillin_rpath (llp_tmp, env_path_list.dirs, ":;",
867 INTUSE(__libc_enable_secure), "LD_LIBRARY_PATH",
870 if (env_path_list.dirs[0] == NULL)
872 free (env_path_list.dirs);
873 env_path_list.dirs = (void *) -1;
876 env_path_list.malloced = 0;
879 env_path_list.dirs = (void *) -1;
884 __attribute__ ((noreturn, noinline))
885 lose (int code, int fd, const char *name, char *realname, struct link_map *l,
886 const char *msg, struct r_debug *r)
888 /* The file might already be closed. */
891 if (l != NULL && l->l_origin != (char *) -1l)
892 free ((char *) l->l_origin);
898 r->r_state = RT_CONSISTENT;
902 _dl_signal_error (code, name, NULL, msg);
906 /* Map in the shared object NAME, actually located in REALNAME, and already
909 #ifndef EXTERNAL_MAP_FROM_FD
913 _dl_map_object_from_fd (const char *name, int fd, struct filebuf *fbp,
914 char *realname, struct link_map *loader, int l_type,
915 int mode, void **stack_endp, Lmid_t nsid)
917 struct link_map *l = NULL;
918 const ElfW(Ehdr) *header;
919 const ElfW(Phdr) *phdr;
920 const ElfW(Phdr) *ph;
924 /* Initialize to keep the compiler happy. */
925 const char *errstring = NULL;
927 struct r_debug *r = _dl_debug_initialize (0, nsid);
928 bool make_consistent = false;
930 /* Get file information. */
931 if (__builtin_expect (__fxstat64 (_STAT_VER, fd, &st) < 0, 0))
933 errstring = N_("cannot stat shared object");
937 lose (errval, fd, name, realname, l, errstring,
938 make_consistent ? r : NULL);
941 /* Look again to see if the real name matched another already loaded. */
942 for (l = GL(dl_ns)[nsid]._ns_loaded; l; l = l->l_next)
943 if (l->l_removed == 0 && l->l_ino == st.st_ino && l->l_dev == st.st_dev)
945 /* The object is already loaded.
946 Just bump its reference count and return it. */
949 /* If the name is not in the list of names for this object add
952 add_name_to_object (l, name);
958 /* When loading into a namespace other than the base one we must
959 avoid loading ld.so since there can only be one copy. Ever. */
960 if (__builtin_expect (nsid != LM_ID_BASE, 0)
961 && ((st.st_ino == GL(dl_rtld_map).l_ino
962 && st.st_dev == GL(dl_rtld_map).l_dev)
963 || _dl_name_match_p (name, &GL(dl_rtld_map))))
965 /* This is indeed ld.so. Create a new link_map which refers to
966 the real one for almost everything. */
967 l = _dl_new_object (realname, name, l_type, loader, mode, nsid);
971 /* Refer to the real descriptor. */
972 l->l_real = &GL(dl_rtld_map);
974 /* No need to bump the refcount of the real object, ld.so will
975 never be unloaded. */
978 /* Add the map for the mirrored object to the object list. */
979 _dl_add_to_namespace_list (l, nsid);
985 if (mode & RTLD_NOLOAD)
987 /* We are not supposed to load the object unless it is already
988 loaded. So return now. */
994 /* Print debugging message. */
995 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0))
996 _dl_debug_printf ("file=%s [%lu]; generating link map\n", name, nsid);
998 /* This is the ELF header. We read it in `open_verify'. */
999 header = (void *) fbp->buf;
1003 if (_dl_zerofd == -1)
1005 _dl_zerofd = _dl_sysdep_open_zero_fill ();
1006 if (_dl_zerofd == -1)
1010 _dl_signal_error (errno, NULL, NULL,
1011 N_("cannot open zero fill device"));
1016 /* Signal that we are going to add new objects. */
1017 if (r->r_state == RT_CONSISTENT)
1020 /* Auditing checkpoint: we are going to add new objects. */
1021 if ((mode & __RTLD_AUDIT) == 0
1022 && __builtin_expect (GLRO(dl_naudit) > 0, 0))
1024 struct link_map *head = GL(dl_ns)[nsid]._ns_loaded;
1025 /* Do not call the functions for any auditing object. */
1026 if (head->l_auditing == 0)
1028 struct audit_ifaces *afct = GLRO(dl_audit);
1029 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
1031 if (afct->activity != NULL)
1032 afct->activity (&head->l_audit[cnt].cookie, LA_ACT_ADD);
1040 /* Notify the debugger we have added some objects. We need to
1041 call _dl_debug_initialize in a static program in case dynamic
1042 linking has not been used before. */
1043 r->r_state = RT_ADD;
1045 make_consistent = true;
1048 assert (r->r_state == RT_ADD);
1050 /* Enter the new object in the list of loaded objects. */
1051 l = _dl_new_object (realname, name, l_type, loader, mode, nsid);
1052 if (__builtin_expect (l == NULL, 0))
1057 errstring = N_("cannot create shared object descriptor");
1058 goto call_lose_errno;
1061 /* Extract the remaining details we need from the ELF header
1062 and then read in the program header table. */
1063 l->l_entry = header->e_entry;
1064 type = header->e_type;
1065 l->l_phnum = header->e_phnum;
1067 maplength = header->e_phnum * sizeof (ElfW(Phdr));
1068 if (header->e_phoff + maplength <= (size_t) fbp->len)
1069 phdr = (void *) (fbp->buf + header->e_phoff);
1072 phdr = alloca (maplength);
1073 __lseek (fd, header->e_phoff, SEEK_SET);
1074 if ((size_t) __libc_read (fd, (void *) phdr, maplength) != maplength)
1076 errstring = N_("cannot read file data");
1077 goto call_lose_errno;
1081 /* On most platforms presume that PT_GNU_STACK is absent and the stack is
1082 * executable. Other platforms default to a nonexecutable stack and don't
1083 * need PT_GNU_STACK to do so. */
1084 uint_fast16_t stack_flags = DEFAULT_STACK_PERMS;
1087 /* Scan the program header table, collecting its load commands. */
1090 ElfW(Addr) mapstart, mapend, dataend, allocend;
1093 } loadcmds[l->l_phnum], *c;
1094 size_t nloadcmds = 0;
1095 bool has_holes = false;
1097 /* The struct is initialized to zero so this is not necessary:
1101 for (ph = phdr; ph < &phdr[l->l_phnum]; ++ph)
1104 /* These entries tell us where to find things once the file's
1105 segments are mapped in. We record the addresses it says
1106 verbatim, and later correct for the run-time load address. */
1108 l->l_ld = (void *) ph->p_vaddr;
1109 l->l_ldnum = ph->p_memsz / sizeof (ElfW(Dyn));
1113 l->l_phdr = (void *) ph->p_vaddr;
1117 /* A load command tells us to map in part of the file.
1118 We record the load commands and process them all later. */
1119 if (__builtin_expect ((ph->p_align & (GLRO(dl_pagesize) - 1)) != 0,
1122 errstring = N_("ELF load command alignment not page-aligned");
1125 if (__builtin_expect (((ph->p_vaddr - ph->p_offset)
1126 & (ph->p_align - 1)) != 0, 0))
1129 = N_("ELF load command address/offset not properly aligned");
1133 c = &loadcmds[nloadcmds++];
1134 c->mapstart = ph->p_vaddr & ~(GLRO(dl_pagesize) - 1);
1135 c->mapend = ((ph->p_vaddr + ph->p_filesz + GLRO(dl_pagesize) - 1)
1136 & ~(GLRO(dl_pagesize) - 1));
1137 c->dataend = ph->p_vaddr + ph->p_filesz;
1138 c->allocend = ph->p_vaddr + ph->p_memsz;
1139 c->mapoff = ph->p_offset & ~(GLRO(dl_pagesize) - 1);
1141 /* Determine whether there is a gap between the last segment
1143 if (nloadcmds > 1 && c[-1].mapend != c->mapstart)
1146 /* Optimize a common case. */
1147 #if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7
1148 c->prot = (PF_TO_PROT
1149 >> ((ph->p_flags & (PF_R | PF_W | PF_X)) * 4)) & 0xf;
1152 if (ph->p_flags & PF_R)
1153 c->prot |= PROT_READ;
1154 if (ph->p_flags & PF_W)
1155 c->prot |= PROT_WRITE;
1156 if (ph->p_flags & PF_X)
1157 c->prot |= PROT_EXEC;
1162 if (ph->p_memsz == 0)
1163 /* Nothing to do for an empty segment. */
1166 l->l_tls_blocksize = ph->p_memsz;
1167 l->l_tls_align = ph->p_align;
1168 if (ph->p_align == 0)
1169 l->l_tls_firstbyte_offset = 0;
1171 l->l_tls_firstbyte_offset = ph->p_vaddr & (ph->p_align - 1);
1172 l->l_tls_initimage_size = ph->p_filesz;
1173 /* Since we don't know the load address yet only store the
1174 offset. We will adjust it later. */
1175 l->l_tls_initimage = (void *) ph->p_vaddr;
1177 /* If not loading the initial set of shared libraries,
1178 check whether we should permit loading a TLS segment. */
1179 if (__builtin_expect (l->l_type == lt_library, 1)
1180 /* If GL(dl_tls_dtv_slotinfo_list) == NULL, then rtld.c did
1181 not set up TLS data structures, so don't use them now. */
1182 || __builtin_expect (GL(dl_tls_dtv_slotinfo_list) != NULL, 1))
1184 /* Assign the next available module ID. */
1185 l->l_tls_modid = _dl_next_tls_modid ();
1190 if (l->l_prev == NULL || (mode & __RTLD_AUDIT) != 0)
1191 /* We are loading the executable itself when the dynamic linker
1192 was executed directly. The setup will happen later. */
1195 /* In a static binary there is no way to tell if we dynamically
1196 loaded libpthread. */
1197 if (GL(dl_error_catch_tsd) == &_dl_initial_error_catch_tsd)
1200 /* We have not yet loaded libpthread.
1201 We can do the TLS setup right now! */
1205 /* The first call allocates TLS bookkeeping data structures.
1206 Then we allocate the TCB for the initial thread. */
1207 if (__builtin_expect (_dl_tls_setup (), 0)
1208 || __builtin_expect ((tcb = _dl_allocate_tls (NULL)) == NULL,
1213 cannot allocate TLS data structures for initial thread");
1217 /* Now we install the TCB in the thread register. */
1218 errstring = TLS_INIT_TP (tcb, 0);
1219 if (__builtin_expect (errstring == NULL, 1))
1221 /* Now we are all good. */
1222 l->l_tls_modid = ++GL(dl_tls_max_dtv_idx);
1226 /* The kernel is too old or somesuch. */
1228 _dl_deallocate_tls (tcb, 1);
1232 /* Uh-oh, the binary expects TLS support but we cannot
1235 errstring = N_("cannot handle TLS data");
1240 stack_flags = ph->p_flags;
1244 l->l_relro_addr = ph->p_vaddr;
1245 l->l_relro_size = ph->p_memsz;
1249 if (__builtin_expect (nloadcmds == 0, 0))
1251 /* This only happens for a bogus object that will be caught with
1252 another error below. But we don't want to go through the
1253 calculations below using NLOADCMDS - 1. */
1254 errstring = N_("object file has no loadable segments");
1258 /* Now process the load commands and map segments into memory. */
1261 /* Length of the sections to be loaded. */
1262 maplength = loadcmds[nloadcmds - 1].allocend - c->mapstart;
1264 if (__builtin_expect (type, ET_DYN) == ET_DYN)
1266 /* This is a position-independent shared object. We can let the
1267 kernel map it anywhere it likes, but we must have space for all
1268 the segments in their specified positions relative to the first.
1269 So we map the first segment without MAP_FIXED, but with its
1270 extent increased to cover all the segments. Then we remove
1271 access from excess portion, and there is known sufficient space
1272 there to remap from the later segments.
1274 As a refinement, sometimes we have an address that we would
1275 prefer to map such objects at; but this is only a preference,
1276 the OS can do whatever it likes. */
1278 mappref = (ELF_PREFERRED_ADDRESS (loader, maplength,
1279 c->mapstart & GLRO(dl_use_load_bias))
1280 - MAP_BASE_ADDR (l));
1282 /* Remember which part of the address space this object uses. */
1283 l->l_map_start = (ElfW(Addr)) __mmap ((void *) mappref, maplength,
1287 if (__builtin_expect ((void *) l->l_map_start == MAP_FAILED, 0))
1290 errstring = N_("failed to map segment from shared object");
1291 goto call_lose_errno;
1294 l->l_map_end = l->l_map_start + maplength;
1295 l->l_addr = l->l_map_start - c->mapstart;
1298 /* Change protection on the excess portion to disallow all access;
1299 the portions we do not remap later will be inaccessible as if
1300 unallocated. Then jump into the normal segment-mapping loop to
1301 handle the portion of the segment past the end of the file
1303 __mprotect ((caddr_t) (l->l_addr + c->mapend),
1304 loadcmds[nloadcmds - 1].mapstart - c->mapend,
1307 l->l_contiguous = 1;
1312 /* This object is loaded at a fixed address. This must never
1313 happen for objects loaded with dlopen(). */
1314 if (__builtin_expect ((mode & __RTLD_OPENEXEC) == 0, 0))
1316 errstring = N_("cannot dynamically load executable");
1320 /* Notify ELF_PREFERRED_ADDRESS that we have to load this one
1322 ELF_FIXED_ADDRESS (loader, c->mapstart);
1325 /* Remember which part of the address space this object uses. */
1326 l->l_map_start = c->mapstart + l->l_addr;
1327 l->l_map_end = l->l_map_start + maplength;
1328 l->l_contiguous = !has_holes;
1330 while (c < &loadcmds[nloadcmds])
1332 if (c->mapend > c->mapstart
1333 /* Map the segment contents from the file. */
1334 && (__mmap ((void *) (l->l_addr + c->mapstart),
1335 c->mapend - c->mapstart, c->prot,
1336 MAP_FIXED|MAP_COPY|MAP_FILE,
1342 if (c->prot & PROT_EXEC)
1343 l->l_text_end = l->l_addr + c->mapend;
1346 && (ElfW(Off)) c->mapoff <= header->e_phoff
1347 && ((size_t) (c->mapend - c->mapstart + c->mapoff)
1348 >= header->e_phoff + header->e_phnum * sizeof (ElfW(Phdr))))
1349 /* Found the program header in this segment. */
1350 l->l_phdr = (void *) (c->mapstart + header->e_phoff - c->mapoff);
1352 if (c->allocend > c->dataend)
1354 /* Extra zero pages should appear at the end of this segment,
1355 after the data mapped from the file. */
1356 ElfW(Addr) zero, zeroend, zeropage;
1358 zero = l->l_addr + c->dataend;
1359 zeroend = l->l_addr + c->allocend;
1360 zeropage = ((zero + GLRO(dl_pagesize) - 1)
1361 & ~(GLRO(dl_pagesize) - 1));
1363 if (zeroend < zeropage)
1364 /* All the extra data is in the last page of the segment.
1365 We can just zero it. */
1368 if (zeropage > zero)
1370 /* Zero the final part of the last page of the segment. */
1371 if (__builtin_expect ((c->prot & PROT_WRITE) == 0, 0))
1374 if (__mprotect ((caddr_t) (zero
1375 & ~(GLRO(dl_pagesize) - 1)),
1376 GLRO(dl_pagesize), c->prot|PROT_WRITE) < 0)
1378 errstring = N_("cannot change memory protections");
1379 goto call_lose_errno;
1382 memset ((void *) zero, '\0', zeropage - zero);
1383 if (__builtin_expect ((c->prot & PROT_WRITE) == 0, 0))
1384 __mprotect ((caddr_t) (zero & ~(GLRO(dl_pagesize) - 1)),
1385 GLRO(dl_pagesize), c->prot);
1388 if (zeroend > zeropage)
1390 /* Map the remaining zero pages in from the zero fill FD. */
1392 mapat = __mmap ((caddr_t) zeropage, zeroend - zeropage,
1393 c->prot, MAP_ANON|MAP_PRIVATE|MAP_FIXED,
1395 if (__builtin_expect (mapat == MAP_FAILED, 0))
1397 errstring = N_("cannot map zero-fill pages");
1398 goto call_lose_errno;
1409 if (__builtin_expect (type == ET_DYN, 0))
1411 errstring = N_("object file has no dynamic section");
1416 l->l_ld = (ElfW(Dyn) *) ((ElfW(Addr)) l->l_ld + l->l_addr);
1418 elf_get_dynamic_info (l, NULL);
1420 /* Make sure we are not dlopen'ing an object that has the
1421 DF_1_NOOPEN flag set. */
1422 if (__builtin_expect (l->l_flags_1 & DF_1_NOOPEN, 0)
1423 && (mode & __RTLD_DLOPEN))
1425 /* We are not supposed to load this object. Free all resources. */
1426 __munmap ((void *) l->l_map_start, l->l_map_end - l->l_map_start);
1428 if (!l->l_libname->dont_free)
1429 free (l->l_libname);
1431 if (l->l_phdr_allocated)
1432 free ((void *) l->l_phdr);
1434 errstring = N_("shared object cannot be dlopen()ed");
1438 if (l->l_phdr == NULL)
1440 /* The program header is not contained in any of the segments.
1441 We have to allocate memory ourself and copy it over from out
1443 ElfW(Phdr) *newp = (ElfW(Phdr) *) malloc (header->e_phnum
1444 * sizeof (ElfW(Phdr)));
1447 errstring = N_("cannot allocate memory for program header");
1448 goto call_lose_errno;
1451 l->l_phdr = memcpy (newp, phdr,
1452 (header->e_phnum * sizeof (ElfW(Phdr))));
1453 l->l_phdr_allocated = 1;
1456 /* Adjust the PT_PHDR value by the runtime load address. */
1457 l->l_phdr = (ElfW(Phdr) *) ((ElfW(Addr)) l->l_phdr + l->l_addr);
1459 if (__builtin_expect ((stack_flags &~ GL(dl_stack_flags)) & PF_X, 0))
1461 if (__builtin_expect (__check_caller (RETURN_ADDRESS (0), allow_ldso),
1464 errstring = N_("invalid caller");
1468 /* The stack is presently not executable, but this module
1469 requires that it be executable. We must change the
1470 protection of the variable which contains the flags used in
1471 the mprotect calls. */
1473 if ((mode & (__RTLD_DLOPEN | __RTLD_AUDIT)) == __RTLD_DLOPEN)
1475 const uintptr_t p = (uintptr_t) &__stack_prot & -GLRO(dl_pagesize);
1476 const size_t s = (uintptr_t) (&__stack_prot + 1) - p;
1478 struct link_map *const m = &GL(dl_rtld_map);
1479 const uintptr_t relro_end = ((m->l_addr + m->l_relro_addr
1481 & -GLRO(dl_pagesize));
1482 if (__builtin_expect (p + s <= relro_end, 1))
1484 /* The variable lies in the region protected by RELRO. */
1485 __mprotect ((void *) p, s, PROT_READ|PROT_WRITE);
1486 __stack_prot |= PROT_READ|PROT_WRITE|PROT_EXEC;
1487 __mprotect ((void *) p, s, PROT_READ);
1490 __stack_prot |= PROT_READ|PROT_WRITE|PROT_EXEC;
1494 __stack_prot |= PROT_READ|PROT_WRITE|PROT_EXEC;
1496 #ifdef check_consistency
1497 check_consistency ();
1500 errval = (*GL(dl_make_stack_executable_hook)) (stack_endp);
1504 cannot enable executable stack as shared object requires");
1509 /* Adjust the address of the TLS initialization image. */
1510 if (l->l_tls_initimage != NULL)
1511 l->l_tls_initimage = (char *) l->l_tls_initimage + l->l_addr;
1513 /* We are done mapping in the file. We no longer need the descriptor. */
1514 if (__builtin_expect (__close (fd) != 0, 0))
1516 errstring = N_("cannot close file descriptor");
1517 goto call_lose_errno;
1519 /* Signal that we closed the file. */
1522 if (l->l_type == lt_library && type == ET_EXEC)
1523 l->l_type = lt_executable;
1525 l->l_entry += l->l_addr;
1527 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0))
1528 _dl_debug_printf ("\
1529 dynamic: 0x%0*lx base: 0x%0*lx size: 0x%0*Zx\n\
1530 entry: 0x%0*lx phdr: 0x%0*lx phnum: %*u\n\n",
1531 (int) sizeof (void *) * 2,
1532 (unsigned long int) l->l_ld,
1533 (int) sizeof (void *) * 2,
1534 (unsigned long int) l->l_addr,
1535 (int) sizeof (void *) * 2, maplength,
1536 (int) sizeof (void *) * 2,
1537 (unsigned long int) l->l_entry,
1538 (int) sizeof (void *) * 2,
1539 (unsigned long int) l->l_phdr,
1540 (int) sizeof (void *) * 2, l->l_phnum);
1542 /* Set up the symbol hash table. */
1545 /* If this object has DT_SYMBOLIC set modify now its scope. We don't
1546 have to do this for the main map. */
1547 if ((mode & RTLD_DEEPBIND) == 0
1548 && __builtin_expect (l->l_info[DT_SYMBOLIC] != NULL, 0)
1549 && &l->l_searchlist != l->l_scope[0])
1551 /* Create an appropriate searchlist. It contains only this map.
1552 This is the definition of DT_SYMBOLIC in SysVr4. */
1553 l->l_symbolic_searchlist.r_list[0] = l;
1554 l->l_symbolic_searchlist.r_nlist = 1;
1556 /* Now move the existing entries one back. */
1557 memmove (&l->l_scope[1], &l->l_scope[0],
1558 (l->l_scope_max - 1) * sizeof (l->l_scope[0]));
1560 /* Now add the new entry. */
1561 l->l_scope[0] = &l->l_symbolic_searchlist;
1564 /* Remember whether this object must be initialized first. */
1565 if (l->l_flags_1 & DF_1_INITFIRST)
1566 GL(dl_initfirst) = l;
1568 /* Finally the file information. */
1569 l->l_dev = st.st_dev;
1570 l->l_ino = st.st_ino;
1572 /* When we profile the SONAME might be needed for something else but
1573 loading. Add it right away. */
1574 if (__builtin_expect (GLRO(dl_profile) != NULL, 0)
1575 && l->l_info[DT_SONAME] != NULL)
1576 add_name_to_object (l, ((const char *) D_PTR (l, l_info[DT_STRTAB])
1577 + l->l_info[DT_SONAME]->d_un.d_val));
1579 /* Now that the object is fully initialized add it to the object list. */
1580 _dl_add_to_namespace_list (l, nsid);
1583 /* Auditing checkpoint: we have a new object. */
1584 if (__builtin_expect (GLRO(dl_naudit) > 0, 0)
1585 && !GL(dl_ns)[l->l_ns]._ns_loaded->l_auditing)
1587 struct audit_ifaces *afct = GLRO(dl_audit);
1588 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
1590 if (afct->objopen != NULL)
1592 l->l_audit[cnt].bindflags
1593 = afct->objopen (l, nsid, &l->l_audit[cnt].cookie);
1595 l->l_audit_any_plt |= l->l_audit[cnt].bindflags != 0;
1606 /* Print search path. */
1608 print_search_path (struct r_search_path_elem **list,
1609 const char *what, const char *name)
1611 char buf[max_dirnamelen + max_capstrlen];
1614 _dl_debug_printf (" search path=");
1616 while (*list != NULL && (*list)->what == what) /* Yes, ==. */
1618 char *endp = __mempcpy (buf, (*list)->dirname, (*list)->dirnamelen);
1621 for (cnt = 0; cnt < ncapstr; ++cnt)
1622 if ((*list)->status[cnt] != nonexisting)
1624 char *cp = __mempcpy (endp, capstr[cnt].str, capstr[cnt].len);
1625 if (cp == buf || (cp == buf + 1 && buf[0] == '/'))
1630 _dl_debug_printf_c (first ? "%s" : ":%s", buf);
1638 _dl_debug_printf_c ("\t\t(%s from file %s)\n", what,
1639 name[0] ? name : rtld_progname);
1641 _dl_debug_printf_c ("\t\t(%s)\n", what);
1644 /* Open a file and verify it is an ELF file for this architecture. We
1645 ignore only ELF files for other architectures. Non-ELF files and
1646 ELF files with different header information cause fatal errors since
1647 this could mean there is something wrong in the installation and the
1648 user might want to know about this. */
1650 open_verify (const char *name, struct filebuf *fbp, struct link_map *loader,
1651 int whatcode, bool *found_other_class, bool free_name)
1653 /* This is the expected ELF header. */
1654 #define ELF32_CLASS ELFCLASS32
1655 #define ELF64_CLASS ELFCLASS64
1656 #ifndef VALID_ELF_HEADER
1657 # define VALID_ELF_HEADER(hdr,exp,size) (memcmp (hdr, exp, size) == 0)
1658 # define VALID_ELF_OSABI(osabi) (osabi == ELFOSABI_SYSV)
1659 # define VALID_ELF_ABIVERSION(osabi,ver) (ver == 0)
1660 #elif defined MORE_ELF_HEADER_DATA
1661 MORE_ELF_HEADER_DATA;
1663 static const unsigned char expected[EI_NIDENT] =
1665 [EI_MAG0] = ELFMAG0,
1666 [EI_MAG1] = ELFMAG1,
1667 [EI_MAG2] = ELFMAG2,
1668 [EI_MAG3] = ELFMAG3,
1669 [EI_CLASS] = ELFW(CLASS),
1670 [EI_DATA] = byteorder,
1671 [EI_VERSION] = EV_CURRENT,
1672 [EI_OSABI] = ELFOSABI_SYSV,
1677 ElfW(Word) vendorlen;
1681 } expected_note = { 4, 16, 1, "GNU" };
1682 /* Initialize it to make the compiler happy. */
1683 const char *errstring = NULL;
1687 /* Give the auditing libraries a chance. */
1688 if (__builtin_expect (GLRO(dl_naudit) > 0, 0) && whatcode != 0
1689 && loader->l_auditing == 0)
1691 struct audit_ifaces *afct = GLRO(dl_audit);
1692 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
1694 if (afct->objsearch != NULL)
1696 name = afct->objsearch (name, &loader->l_audit[cnt].cookie,
1699 /* Ignore the path. */
1708 /* Open the file. We always open files read-only. */
1709 int fd = __open (name, O_RDONLY | O_CLOEXEC);
1713 ElfW(Phdr) *phdr, *ph;
1714 ElfW(Word) *abi_note;
1715 unsigned int osversion;
1718 /* We successfully openened the file. Now verify it is a file
1721 fbp->len = __libc_read (fd, fbp->buf, sizeof (fbp->buf));
1723 /* This is where the ELF header is loaded. */
1724 assert (sizeof (fbp->buf) > sizeof (ElfW(Ehdr)));
1725 ehdr = (ElfW(Ehdr) *) fbp->buf;
1727 /* Now run the tests. */
1728 if (__builtin_expect (fbp->len < (ssize_t) sizeof (ElfW(Ehdr)), 0))
1731 errstring = (errval == 0
1732 ? N_("file too short") : N_("cannot read file data"));
1736 char *realname = (char *) name;
1737 name = strdupa (realname);
1740 lose (errval, fd, name, NULL, NULL, errstring, NULL);
1743 /* See whether the ELF header is what we expect. */
1744 if (__builtin_expect (! VALID_ELF_HEADER (ehdr->e_ident, expected,
1746 || !VALID_ELF_ABIVERSION (ehdr->e_ident[EI_OSABI],
1747 ehdr->e_ident[EI_ABIVERSION])
1748 || memcmp (&ehdr->e_ident[EI_PAD],
1750 EI_NIDENT - EI_PAD) != 0,
1753 /* Something is wrong. */
1754 const Elf32_Word *magp = (const void *) ehdr->e_ident;
1756 #if BYTE_ORDER == LITTLE_ENDIAN
1757 ((ELFMAG0 << (EI_MAG0 * 8)) |
1758 (ELFMAG1 << (EI_MAG1 * 8)) |
1759 (ELFMAG2 << (EI_MAG2 * 8)) |
1760 (ELFMAG3 << (EI_MAG3 * 8)))
1762 ((ELFMAG0 << (EI_MAG3 * 8)) |
1763 (ELFMAG1 << (EI_MAG2 * 8)) |
1764 (ELFMAG2 << (EI_MAG1 * 8)) |
1765 (ELFMAG3 << (EI_MAG0 * 8)))
1768 errstring = N_("invalid ELF header");
1769 else if (ehdr->e_ident[EI_CLASS] != ELFW(CLASS))
1771 /* This is not a fatal error. On architectures where
1772 32-bit and 64-bit binaries can be run this might
1774 *found_other_class = true;
1777 else if (ehdr->e_ident[EI_DATA] != byteorder)
1779 if (BYTE_ORDER == BIG_ENDIAN)
1780 errstring = N_("ELF file data encoding not big-endian");
1782 errstring = N_("ELF file data encoding not little-endian");
1784 else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT)
1786 = N_("ELF file version ident does not match current one");
1787 /* XXX We should be able so set system specific versions which are
1789 else if (!VALID_ELF_OSABI (ehdr->e_ident[EI_OSABI]))
1790 errstring = N_("ELF file OS ABI invalid");
1791 else if (!VALID_ELF_ABIVERSION (ehdr->e_ident[EI_OSABI],
1792 ehdr->e_ident[EI_ABIVERSION]))
1793 errstring = N_("ELF file ABI version invalid");
1794 else if (memcmp (&ehdr->e_ident[EI_PAD], &expected[EI_PAD],
1795 EI_NIDENT - EI_PAD) != 0)
1796 errstring = N_("nonzero padding in e_ident");
1798 /* Otherwise we don't know what went wrong. */
1799 errstring = N_("internal error");
1804 if (__builtin_expect (ehdr->e_version, EV_CURRENT) != EV_CURRENT)
1806 errstring = N_("ELF file version does not match current one");
1809 if (! __builtin_expect (elf_machine_matches_host (ehdr), 1))
1811 else if (__builtin_expect (ehdr->e_type, ET_DYN) != ET_DYN
1812 && __builtin_expect (ehdr->e_type, ET_EXEC) != ET_EXEC)
1814 errstring = N_("only ET_DYN and ET_EXEC can be loaded");
1817 else if (__builtin_expect (ehdr->e_phentsize, sizeof (ElfW(Phdr)))
1818 != sizeof (ElfW(Phdr)))
1820 errstring = N_("ELF file's phentsize not the expected size");
1824 maplength = ehdr->e_phnum * sizeof (ElfW(Phdr));
1825 if (ehdr->e_phoff + maplength <= (size_t) fbp->len)
1826 phdr = (void *) (fbp->buf + ehdr->e_phoff);
1829 phdr = alloca (maplength);
1830 __lseek (fd, ehdr->e_phoff, SEEK_SET);
1831 if ((size_t) __libc_read (fd, (void *) phdr, maplength) != maplength)
1835 errstring = N_("cannot read file data");
1840 /* Check .note.ABI-tag if present. */
1841 for (ph = phdr; ph < &phdr[ehdr->e_phnum]; ++ph)
1842 if (ph->p_type == PT_NOTE && ph->p_filesz >= 32 && ph->p_align >= 4)
1844 ElfW(Addr) size = ph->p_filesz;
1846 if (ph->p_offset + size <= (size_t) fbp->len)
1847 abi_note = (void *) (fbp->buf + ph->p_offset);
1850 abi_note = alloca (size);
1851 __lseek (fd, ph->p_offset, SEEK_SET);
1852 if (__libc_read (fd, (void *) abi_note, size) != size)
1856 while (memcmp (abi_note, &expected_note, sizeof (expected_note)))
1858 #define ROUND(len) (((len) + sizeof (ElfW(Word)) - 1) & -sizeof (ElfW(Word)))
1859 ElfW(Addr) note_size = 3 * sizeof (ElfW(Word))
1860 + ROUND (abi_note[0])
1861 + ROUND (abi_note[1]);
1863 if (size - 32 < note_size)
1869 abi_note = (void *) abi_note + note_size;
1875 osversion = (abi_note[5] & 0xff) * 65536
1876 + (abi_note[6] & 0xff) * 256
1877 + (abi_note[7] & 0xff);
1878 if (abi_note[4] != __ABI_TAG_OS
1879 || (GLRO(dl_osversion) && GLRO(dl_osversion) < osversion))
1883 __set_errno (ENOENT);
1894 /* Try to open NAME in one of the directories in *DIRSP.
1895 Return the fd, or -1. If successful, fill in *REALNAME
1896 with the malloc'd full directory name. If it turns out
1897 that none of the directories in *DIRSP exists, *DIRSP is
1898 replaced with (void *) -1, and the old value is free()d
1899 if MAY_FREE_DIRS is true. */
1902 open_path (const char *name, size_t namelen, int secure,
1903 struct r_search_path_struct *sps, char **realname,
1904 struct filebuf *fbp, struct link_map *loader, int whatcode,
1905 bool *found_other_class)
1907 struct r_search_path_elem **dirs = sps->dirs;
1910 const char *current_what = NULL;
1913 if (__builtin_expect (dirs == NULL, 0))
1914 /* We're called before _dl_init_paths when loading the main executable
1915 given on the command line when rtld is run directly. */
1918 buf = alloca (max_dirnamelen + max_capstrlen + namelen);
1921 struct r_search_path_elem *this_dir = *dirs;
1928 /* If we are debugging the search for libraries print the path
1929 now if it hasn't happened now. */
1930 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_LIBS, 0)
1931 && current_what != this_dir->what)
1933 current_what = this_dir->what;
1934 print_search_path (dirs, current_what, this_dir->where);
1937 edp = (char *) __mempcpy (buf, this_dir->dirname, this_dir->dirnamelen);
1938 for (cnt = 0; fd == -1 && cnt < ncapstr; ++cnt)
1940 /* Skip this directory if we know it does not exist. */
1941 if (this_dir->status[cnt] == nonexisting)
1945 ((char *) __mempcpy (__mempcpy (edp, capstr[cnt].str,
1950 /* Print name we try if this is wanted. */
1951 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_LIBS, 0))
1952 _dl_debug_printf (" trying file=%s\n", buf);
1954 fd = open_verify (buf, fbp, loader, whatcode, found_other_class,
1956 if (this_dir->status[cnt] == unknown)
1959 this_dir->status[cnt] = existing;
1960 /* Do not update the directory information when loading
1961 auditing code. We must try to disturb the program as
1962 little as possible. */
1963 else if (loader == NULL
1964 || GL(dl_ns)[loader->l_ns]._ns_loaded->l_auditing == 0)
1966 /* We failed to open machine dependent library. Let's
1967 test whether there is any directory at all. */
1970 buf[buflen - namelen - 1] = '\0';
1972 if (__xstat64 (_STAT_VER, buf, &st) != 0
1973 || ! S_ISDIR (st.st_mode))
1974 /* The directory does not exist or it is no directory. */
1975 this_dir->status[cnt] = nonexisting;
1977 this_dir->status[cnt] = existing;
1981 /* Remember whether we found any existing directory. */
1982 here_any |= this_dir->status[cnt] != nonexisting;
1984 if (fd != -1 && __builtin_expect (secure, 0)
1985 && INTUSE(__libc_enable_secure))
1987 /* This is an extra security effort to make sure nobody can
1988 preload broken shared objects which are in the trusted
1989 directories and so exploit the bugs. */
1992 if (__fxstat64 (_STAT_VER, fd, &st) != 0
1993 || (st.st_mode & S_ISUID) == 0)
1995 /* The shared object cannot be tested for being SUID
1996 or this bit is not set. In this case we must not
2000 /* We simply ignore the file, signal this by setting
2001 the error value which would have been set by `open'. */
2009 *realname = (char *) malloc (buflen);
2010 if (*realname != NULL)
2012 memcpy (*realname, buf, buflen);
2017 /* No memory for the name, we certainly won't be able
2018 to load and link it. */
2023 if (here_any && (err = errno) != ENOENT && err != EACCES)
2024 /* The file exists and is readable, but something went wrong. */
2027 /* Remember whether we found anything. */
2030 while (*++dirs != NULL);
2032 /* Remove the whole path if none of the directories exists. */
2033 if (__builtin_expect (! any, 0))
2035 /* Paths which were allocated using the minimal malloc() in ld.so
2036 must not be freed using the general free() in libc. */
2040 /* rtld_search_dirs is attribute_relro, therefore avoid writing
2042 if (sps != &rtld_search_dirs)
2043 sps->dirs = (void *) -1;
2049 /* Map in the shared object file NAME. */
2053 _dl_map_object (struct link_map *loader, const char *name,
2054 int type, int trace_mode, int mode, Lmid_t nsid)
2063 assert (nsid < GL(dl_nns));
2065 /* Look for this name among those already loaded. */
2066 for (l = GL(dl_ns)[nsid]._ns_loaded; l; l = l->l_next)
2068 /* If the requested name matches the soname of a loaded object,
2069 use that object. Elide this check for names that have not
2071 if (__builtin_expect (l->l_faked, 0) != 0
2072 || __builtin_expect (l->l_removed, 0) != 0)
2074 if (!_dl_name_match_p (name, l))
2078 if (__builtin_expect (l->l_soname_added, 1)
2079 || l->l_info[DT_SONAME] == NULL)
2082 soname = ((const char *) D_PTR (l, l_info[DT_STRTAB])
2083 + l->l_info[DT_SONAME]->d_un.d_val);
2084 if (strcmp (name, soname) != 0)
2087 /* We have a match on a new name -- cache it. */
2088 add_name_to_object (l, soname);
2089 l->l_soname_added = 1;
2092 /* We have a match. */
2096 /* Display information if we are debugging. */
2097 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_FILES, 0)
2099 _dl_debug_printf ((mode & __RTLD_CALLMAP) == 0
2100 ? "\nfile=%s [%lu]; needed by %s [%lu]\n"
2101 : "\nfile=%s [%lu]; dynamically loaded by %s [%lu]\n",
2102 name, nsid, loader->l_name[0]
2103 ? loader->l_name : rtld_progname, loader->l_ns);
2106 /* Give the auditing libraries a chance to change the name before we
2108 if (__builtin_expect (GLRO(dl_naudit) > 0, 0)
2109 && (loader == NULL || loader->l_auditing == 0))
2111 struct audit_ifaces *afct = GLRO(dl_audit);
2112 for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
2114 if (afct->objsearch != NULL)
2116 name = afct->objsearch (name, &loader->l_audit[cnt].cookie,
2120 /* Do not try anything further. */
2131 /* Will be true if we found a DSO which is of the other ELF class. */
2132 bool found_other_class = false;
2134 if (strchr (name, '/') == NULL)
2136 /* Search for NAME in several places. */
2138 size_t namelen = strlen (name) + 1;
2140 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_LIBS, 0))
2141 _dl_debug_printf ("find library=%s [%lu]; searching\n", name, nsid);
2145 /* When the object has the RUNPATH information we don't use any
2147 if (loader == NULL || loader->l_info[DT_RUNPATH] == NULL)
2149 /* This is the executable's map (if there is one). Make sure that
2150 we do not look at it twice. */
2151 struct link_map *main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
2152 bool did_main_map = false;
2154 /* First try the DT_RPATH of the dependent object that caused NAME
2155 to be loaded. Then that object's dependent, and on up. */
2156 for (l = loader; l; l = l->l_loader)
2157 if (cache_rpath (l, &l->l_rpath_dirs, DT_RPATH, "RPATH"))
2159 fd = open_path (name, namelen, mode & __RTLD_SECURE,
2161 &realname, &fb, loader, LA_SER_RUNPATH,
2162 &found_other_class);
2166 did_main_map |= l == main_map;
2169 /* If dynamically linked, try the DT_RPATH of the executable
2170 itself. NB: we do this for lookups in any namespace. */
2171 if (fd == -1 && !did_main_map
2172 && main_map != NULL && main_map->l_type != lt_loaded
2173 && cache_rpath (main_map, &main_map->l_rpath_dirs, DT_RPATH,
2175 fd = open_path (name, namelen, mode & __RTLD_SECURE,
2176 &main_map->l_rpath_dirs,
2177 &realname, &fb, loader ?: main_map, LA_SER_RUNPATH,
2178 &found_other_class);
2181 /* Try the LD_LIBRARY_PATH environment variable. */
2182 if (fd == -1 && env_path_list.dirs != (void *) -1)
2183 fd = open_path (name, namelen, mode & __RTLD_SECURE, &env_path_list,
2185 loader ?: GL(dl_ns)[LM_ID_BASE]._ns_loaded,
2186 LA_SER_LIBPATH, &found_other_class);
2188 /* Look at the RUNPATH information for this binary. */
2189 if (fd == -1 && loader != NULL
2190 && cache_rpath (loader, &loader->l_runpath_dirs,
2191 DT_RUNPATH, "RUNPATH"))
2192 fd = open_path (name, namelen, mode & __RTLD_SECURE,
2193 &loader->l_runpath_dirs, &realname, &fb, loader,
2194 LA_SER_RUNPATH, &found_other_class);
2197 && (__builtin_expect (! (mode & __RTLD_SECURE), 1)
2198 || ! INTUSE(__libc_enable_secure)))
2200 /* Check the list of libraries in the file /etc/ld.so.cache,
2201 for compatibility with Linux's ldconfig program. */
2202 const char *cached = _dl_load_cache_lookup (name);
2207 // XXX Correct to unconditionally default to namespace 0?
2209 ?: GL(dl_ns)[LM_ID_BASE]._ns_loaded
2210 ?: &GL(dl_rtld_map));
2215 /* If the loader has the DF_1_NODEFLIB flag set we must not
2216 use a cache entry from any of these directories. */
2219 /* 'l' is always != NULL for dynamically linked objects. */
2222 __builtin_expect (l->l_flags_1 & DF_1_NODEFLIB, 0))
2224 const char *dirp = system_dirs;
2225 unsigned int cnt = 0;
2229 if (memcmp (cached, dirp, system_dirs_len[cnt]) == 0)
2231 /* The prefix matches. Don't use the entry. */
2236 dirp += system_dirs_len[cnt] + 1;
2239 while (cnt < nsystem_dirs_len);
2244 fd = open_verify (cached,
2245 &fb, loader ?: GL(dl_ns)[nsid]._ns_loaded,
2246 LA_SER_CONFIG, &found_other_class, false);
2247 if (__builtin_expect (fd != -1, 1))
2249 realname = local_strdup (cached);
2250 if (realname == NULL)
2260 /* Finally, try the default path. */
2262 && ((l = loader ?: GL(dl_ns)[nsid]._ns_loaded) == NULL
2263 || __builtin_expect (!(l->l_flags_1 & DF_1_NODEFLIB), 1))
2264 && rtld_search_dirs.dirs != (void *) -1)
2265 fd = open_path (name, namelen, mode & __RTLD_SECURE, &rtld_search_dirs,
2266 &realname, &fb, l, LA_SER_DEFAULT, &found_other_class);
2268 /* Add another newline when we are tracing the library loading. */
2269 if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_LIBS, 0))
2270 _dl_debug_printf ("\n");
2274 /* The path may contain dynamic string tokens. */
2276 ? expand_dynamic_string_token (loader, name, 0)
2277 : local_strdup (name));
2278 if (realname == NULL)
2282 fd = open_verify (realname, &fb,
2283 loader ?: GL(dl_ns)[nsid]._ns_loaded, 0,
2284 &found_other_class, true);
2285 if (__builtin_expect (fd, 0) == -1)
2293 /* In case the LOADER information has only been provided to get to
2294 the appropriate RUNPATH/RPATH information we do not need it
2296 if (mode & __RTLD_CALLMAP)
2299 if (__builtin_expect (fd, 0) == -1)
2302 && __builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_PRELINK, 0) == 0)
2304 /* We haven't found an appropriate library. But since we
2305 are only interested in the list of libraries this isn't
2306 so severe. Fake an entry with all the information we
2308 static const Elf_Symndx dummy_bucket = STN_UNDEF;
2310 /* Allocate a new object map. */
2311 if ((name_copy = local_strdup (name)) == NULL
2312 || (l = _dl_new_object (name_copy, name, type, loader,
2313 mode, nsid)) == NULL)
2316 _dl_signal_error (ENOMEM, name, NULL,
2317 N_("cannot create shared object descriptor"));
2319 /* Signal that this is a faked entry. */
2321 /* Since the descriptor is initialized with zero we do not
2323 l->l_reserved = 0; */
2324 l->l_buckets = &dummy_bucket;
2328 /* Enter the object in the object list. */
2329 _dl_add_to_namespace_list (l, nsid);
2333 else if (found_other_class)
2334 _dl_signal_error (0, name, NULL,
2335 ELFW(CLASS) == ELFCLASS32
2336 ? N_("wrong ELF class: ELFCLASS64")
2337 : N_("wrong ELF class: ELFCLASS32"));
2339 _dl_signal_error (errno, name, NULL,
2340 N_("cannot open shared object file"));
2343 void *stack_end = __libc_stack_end;
2344 return _dl_map_object_from_fd (name, fd, &fb, realname, loader, type, mode,
2351 _dl_rtld_di_serinfo (struct link_map *loader, Dl_serinfo *si, bool counting)
2359 unsigned int idx = 0;
2360 char *allocptr = (char *) &si->dls_serpath[si->dls_cnt];
2361 void add_path (const struct r_search_path_struct *sps, unsigned int flags)
2362 # define add_path(sps, flags) add_path(sps, 0) /* XXX */
2364 if (sps->dirs != (void *) -1)
2366 struct r_search_path_elem **dirs = sps->dirs;
2369 const struct r_search_path_elem *const r = *dirs++;
2373 si->dls_size += MAX (2, r->dirnamelen);
2377 Dl_serpath *const sp = &si->dls_serpath[idx++];
2378 sp->dls_name = allocptr;
2379 if (r->dirnamelen < 2)
2380 *allocptr++ = r->dirnamelen ? '/' : '.';
2382 allocptr = __mempcpy (allocptr,
2383 r->dirname, r->dirnamelen - 1);
2385 sp->dls_flags = flags;
2388 while (*dirs != NULL);
2392 /* When the object has the RUNPATH information we don't use any RPATHs. */
2393 if (loader->l_info[DT_RUNPATH] == NULL)
2395 /* First try the DT_RPATH of the dependent object that caused NAME
2396 to be loaded. Then that object's dependent, and on up. */
2398 struct link_map *l = loader;
2401 if (cache_rpath (l, &l->l_rpath_dirs, DT_RPATH, "RPATH"))
2402 add_path (&l->l_rpath_dirs, XXX_RPATH);
2407 /* If dynamically linked, try the DT_RPATH of the executable itself. */
2408 if (loader->l_ns == LM_ID_BASE)
2410 l = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
2411 if (l != NULL && l->l_type != lt_loaded && l != loader)
2412 if (cache_rpath (l, &l->l_rpath_dirs, DT_RPATH, "RPATH"))
2413 add_path (&l->l_rpath_dirs, XXX_RPATH);
2417 /* Try the LD_LIBRARY_PATH environment variable. */
2418 add_path (&env_path_list, XXX_ENV);
2420 /* Look at the RUNPATH information for this binary. */
2421 if (cache_rpath (loader, &loader->l_runpath_dirs, DT_RUNPATH, "RUNPATH"))
2422 add_path (&loader->l_runpath_dirs, XXX_RUNPATH);
2425 Here is where ld.so.cache gets checked, but we don't have
2426 a way to indicate that in the results for Dl_serinfo. */
2428 /* Finally, try the default path. */
2429 if (!(loader->l_flags_1 & DF_1_NODEFLIB))
2430 add_path (&rtld_search_dirs, XXX_default);
2433 /* Count the struct size before the string area, which we didn't
2434 know before we completed dls_cnt. */
2435 si->dls_size += (char *) &si->dls_serpath[si->dls_cnt] - (char *) si;