1 /* Map in a shared object's segments from the file.
2 Copyright (C) 1995, 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If not,
17 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA. */
26 #include <elf/ldsodefs.h>
28 #include <sys/param.h>
30 #include <sys/types.h>
31 #include "dynamic-link.h"
32 #include <stdio-common/_itoa.h>
34 #include <dl-origin.h>
37 /* On some systems, no flag bits are given to specify file mapping. */
42 /* The right way to map in the shared library files is MAP_COPY, which
43 makes a virtual copy of the data at the time of the mmap call; this
44 guarantees the mapped pages will be consistent even if the file is
45 overwritten. Some losing VM systems like Linux's lack MAP_COPY. All we
46 get is MAP_PRIVATE, which copies each page when it is modified; this
47 means if the file is overwritten, we may at some point get some pages
48 from the new version after starting with pages from the old version. */
50 #define MAP_COPY MAP_PRIVATE
53 /* Some systems link their relocatable objects for another base address
54 than 0. We want to know the base address for these such that we can
55 subtract this address from the segment addresses during mapping.
56 This results in a more efficient address space usage. Defaults to
57 zero for almost all systems. */
59 #define MAP_BASE_ADDR(l) 0
64 #if BYTE_ORDER == BIG_ENDIAN
65 #define byteorder ELFDATA2MSB
66 #define byteorder_name "big-endian"
67 #elif BYTE_ORDER == LITTLE_ENDIAN
68 #define byteorder ELFDATA2LSB
69 #define byteorder_name "little-endian"
71 #error "Unknown BYTE_ORDER " BYTE_ORDER
72 #define byteorder ELFDATANONE
75 #define STRING(x) __STRING (x)
78 /* The fd is not examined when using MAP_ANON. */
82 #define ANONFD _dl_zerofd
85 /* Handle situations where we have a preferred location in memory for
86 the shared objects. */
87 #ifdef ELF_PREFERRED_ADDRESS_DATA
88 ELF_PREFERRED_ADDRESS_DATA;
90 #ifndef ELF_PREFERRED_ADDRESS
91 #define ELF_PREFERRED_ADDRESS(loader, maplength, mapstartpref) (mapstartpref)
93 #ifndef ELF_FIXED_ADDRESS
94 #define ELF_FIXED_ADDRESS(loader, mapstart) ((void) 0)
99 extern const char *_dl_platform;
100 extern size_t _dl_platformlen;
102 /* This is the decomposed LD_LIBRARY_PATH search path. */
103 static struct r_search_path_elem **env_path_list;
105 /* List of the hardware capabilities we might end up using. */
106 static const struct r_strlenpair *capstr;
107 static size_t ncapstr;
108 static size_t max_capstrlen;
110 const unsigned char _dl_pf_to_prot[8] =
115 [PF_R | PF_W] = PROT_READ | PROT_WRITE,
117 [PF_R | PF_X] = PROT_READ | PROT_EXEC,
118 [PF_W | PF_X] = PROT_WRITE | PROT_EXEC,
119 [PF_R | PF_W | PF_X] = PROT_READ | PROT_WRITE | PROT_EXEC
123 /* Get the generated information about the trusted directories. */
124 #include "trusted-dirs.h"
126 static const char system_dirs[] = SYSTEM_DIRS;
127 static const size_t system_dirs_len[] =
132 /* This function has no public prototype. */
133 extern ssize_t __libc_read (int, void *, size_t);
136 /* Local version of `strdup' function. */
138 local_strdup (const char *s)
140 size_t len = strlen (s) + 1;
141 void *new = malloc (len);
146 return (char *) memcpy (new, s, len);
149 /* Return copy of argument with all recognized dynamic string tokens
150 ($ORIGIN and $PLATFORM for now) replaced. On some platforms it
151 might not be possible to determine the path from which the object
152 belonging to the map is loaded. In this case the path element
153 containing $ORIGIN is left out. */
155 expand_dynamic_string_token (struct link_map *l, const char *s)
157 /* We make two runs over the string. First we determine how large the
158 resulting string is and then we copy it over. Since this is now
159 frequently executed operation we are looking here not for performance
160 but rather for code size. */
165 char *result, *last_elem, *wp;
167 sf = strchr (s, '$');
172 /* $ORIGIN is not expanded for SUID/GUID programs. */
173 if ((((!__libc_enable_secure
174 && strncmp (&sf[1], "ORIGIN", 6) == 0 && (len = 7) != 0)
175 || (strncmp (&sf[1], "PLATFORM", 8) == 0 && (len = 9) != 0))
176 && (s[len] == '\0' || s[len] == '/' || s[len] == ':'))
178 && ((!__libc_enable_secure
179 && strncmp (&sf[2], "ORIGIN}", 7) == 0 && (len = 9) != 0)
180 || (strncmp (&sf[2], "PLATFORM}", 9) == 0
181 && (len = 11) != 0))))
184 sf = strchr (sf + len, '$');
187 /* If we do not have to replace anything simply copy the string. */
189 return local_strdup (s);
191 /* Now we make a guess how many extra characters on top of the length
192 of S we need to represent the result. We know that we have CNT
193 replacements. Each at most can use
194 MAX (strlen (ORIGIN), strlen (_dl_platform))
195 minus 7 (which is the length of "$ORIGIN").
197 First get the origin string if it is not available yet. This can
198 only happen for the map of the executable. */
199 if (l->l_origin == NULL)
201 assert (l->l_name[0] == '\0');
202 l->l_origin = get_origin ();
203 origin_len = (l->l_origin && l->l_origin != (char *) -1
204 ? strlen (l->l_origin) : 0);
207 origin_len = l->l_origin == (char *) -1 ? 0 : strlen (l->l_origin);
209 total = strlen (s) + cnt * (MAX (origin_len, _dl_platformlen) - 7);
210 result = (char *) malloc (total + 1);
214 /* Now fill the result path. While copying over the string we keep
215 track of the start of the last path element. When we come accross
216 a DST we copy over the value or (if the value is not available)
217 leave the entire path element out. */
218 last_elem = wp = result;
226 if ((((strncmp (&s[1], "ORIGIN", 6) == 0 && (len = 7) != 0)
227 || (strncmp (&s[1], "PLATFORM", 8) == 0 && (len = 9) != 0))
228 && (s[len] == '\0' || s[len] == '/' || s[len] == ':'))
230 && ((strncmp (&s[2], "ORIGIN}", 7) == 0 && (len = 9) != 0)
231 || (strncmp (&s[2], "PLATFORM}", 9) == 0
232 && (len = 11) != 0))))
234 repl = ((len == 7 || s[2] == 'O')
235 ? (__libc_enable_secure ? NULL : l->l_origin)
238 if (repl != NULL && repl != (const char *) -1)
240 wp = __stpcpy (wp, repl);
245 /* We cannot use this path element, the value of the
246 replacement is unknown. */
249 while (*s != '\0' && *s != ':')
254 /* No DST we recognize. */
272 /* Add `name' to the list of names for a particular shared object.
273 `name' is expected to have been allocated with malloc and will
274 be freed if the shared object already has this name.
275 Returns false if the object already had this name. */
278 add_name_to_object (struct link_map *l, const char *name)
280 struct libname_list *lnp, *lastp;
281 struct libname_list *newname;
285 for (lnp = l->l_libname; lnp != NULL; lastp = lnp, lnp = lnp->next)
286 if (strcmp (name, lnp->name) == 0)
289 name_len = strlen (name) + 1;
290 newname = malloc (sizeof *newname + name_len);
293 /* No more memory. */
294 _dl_signal_error (ENOMEM, name, "cannot allocate name record");
297 /* The object should have a libname set from _dl_new_object. */
298 assert (lastp != NULL);
300 newname->name = memcpy (newname + 1, name, name_len);
301 newname->next = NULL;
302 lastp->next = newname;
305 /* All known directories in sorted order. */
306 static struct r_search_path_elem *all_dirs;
308 /* Standard search directories. */
309 static struct r_search_path_elem **rtld_search_dirs;
311 static size_t max_dirnamelen;
313 static inline struct r_search_path_elem **
314 fillin_rpath (char *rpath, struct r_search_path_elem **result, const char *sep,
315 int check_trusted, const char *what, const char *where)
320 while ((cp = __strsep (&rpath, sep)) != NULL)
322 struct r_search_path_elem *dirp;
323 size_t len = strlen (cp);
325 /* `strsep' can pass an empty string. This has to be
326 interpreted as `use the current directory'. */
329 static const char curwd[] = "./";
333 /* Remove trailing slashes (except for "/"). */
334 while (len > 1 && cp[len - 1] == '/')
337 /* Now add one if there is none so far. */
338 if (len > 0 && cp[len - 1] != '/')
341 /* Make sure we don't use untrusted directories if we run SUID. */
344 const char *trun = system_dirs;
347 /* All trusted directories must be complete names. */
352 idx < sizeof (system_dirs_len) / sizeof (system_dirs_len[0]);
355 if (len == system_dirs_len[idx] && memcmp (trun, cp, len) == 0)
359 trun += system_dirs_len[idx] + 1;
362 if (idx == sizeof (system_dirs_len) / sizeof (system_dirs_len[0]))
363 /* It's no trusted directory, skip it. */
367 /* See if this directory is already known. */
368 for (dirp = all_dirs; dirp != NULL; dirp = dirp->next)
369 if (dirp->dirnamelen == len && memcmp (cp, dirp->dirname, len) == 0)
374 /* It is available, see whether it's on our own list. */
376 for (cnt = 0; cnt < nelems; ++cnt)
377 if (result[cnt] == dirp)
381 result[nelems++] = dirp;
387 /* It's a new directory. Create an entry and add it. */
388 dirp = (struct r_search_path_elem *)
389 malloc (sizeof (*dirp) + ncapstr * sizeof (enum r_dir_status));
391 _dl_signal_error (ENOMEM, NULL,
392 "cannot create cache for search path");
395 dirp->dirnamelen = len;
397 if (len > max_dirnamelen)
398 max_dirnamelen = len;
400 /* We have to make sure all the relative directories are never
401 ignored. The current directory might change and all our
402 saved information would be void. */
404 for (cnt = 0; cnt < ncapstr; ++cnt)
405 dirp->status[cnt] = existing;
407 for (cnt = 0; cnt < ncapstr; ++cnt)
408 dirp->status[cnt] = unknown;
413 dirp->next = all_dirs;
416 /* Put it in the result array. */
417 result[nelems++] = dirp;
421 /* Terminate the array. */
422 result[nelems] = NULL;
428 static struct r_search_path_elem **
430 decompose_rpath (const char *rpath, struct link_map *l)
432 /* Make a copy we can work with. */
433 const char *where = l->l_name;
436 struct r_search_path_elem **result;
439 /* First see whether we must forget the RPATH from this object. */
440 if (_dl_inhibit_rpath != NULL && !__libc_enable_secure)
442 const char *found = strstr (_dl_inhibit_rpath, where);
445 size_t len = strlen (where);
446 if ((found == _dl_inhibit_rpath || found[-1] == ':')
447 && (found[len] == '\0' || found[len] == ':'))
449 /* This object is on the list of objects for which the RPATH
451 result = (struct r_search_path_elem **)
452 malloc (sizeof (*result));
454 _dl_signal_error (ENOMEM, NULL,
455 "cannot create cache for search path");
463 /* Make a writable copy. At the same time expand possible dynamic
465 copy = expand_dynamic_string_token (l, rpath);
467 _dl_signal_error (ENOMEM, NULL, "cannot create RPATH copy");
469 /* Count the number of necessary elements in the result array. */
471 for (cp = copy; *cp != '\0'; ++cp)
475 /* Allocate room for the result. NELEMS + 1 is an upper limit for the
476 number of necessary entries. */
477 result = (struct r_search_path_elem **) malloc ((nelems + 1 + 1)
480 _dl_signal_error (ENOMEM, NULL, "cannot create cache for search path");
482 return fillin_rpath (copy, result, ":", 0, "RPATH", where);
488 _dl_init_paths (const char *llp)
492 struct r_search_path_elem *pelem, **aelem;
498 /* Fill in the information about the application's RPATH and the
499 directories addressed by the LD_LIBRARY_PATH environment variable. */
501 /* Get the capabilities. */
502 capstr = _dl_important_hwcaps (_dl_platform, _dl_platformlen,
503 &ncapstr, &max_capstrlen);
505 /* First set up the rest of the default search directory entries. */
506 aelem = rtld_search_dirs = (struct r_search_path_elem **)
507 malloc ((sizeof (system_dirs_len) / sizeof (system_dirs_len[0]))
508 * sizeof (struct r_search_path_elem *));
509 if (rtld_search_dirs == NULL)
510 _dl_signal_error (ENOMEM, NULL, "cannot create search path array");
512 round_size = ((2 * sizeof (struct r_search_path_elem) - 1
513 + ncapstr * sizeof (enum r_dir_status))
514 / sizeof (struct r_search_path_elem));
516 rtld_search_dirs[0] = (struct r_search_path_elem *)
517 malloc ((sizeof (system_dirs) / sizeof (system_dirs[0]) - 1)
518 * round_size * sizeof (struct r_search_path_elem));
519 if (rtld_search_dirs[0] == NULL)
520 _dl_signal_error (ENOMEM, NULL, "cannot create cache for search path");
522 pelem = all_dirs = rtld_search_dirs[0];
532 pelem->what = "system search path";
535 pelem->dirname = strp;
536 pelem->dirnamelen = system_dirs_len[idx];
537 strp += system_dirs_len[idx] + 1;
539 if (pelem->dirname[0] != '/')
540 for (cnt = 0; cnt < ncapstr; ++cnt)
541 pelem->status[cnt] = existing;
543 for (cnt = 0; cnt < ncapstr; ++cnt)
544 pelem->status[cnt] = unknown;
546 pelem->next = (++idx == (sizeof (system_dirs_len)
547 / sizeof (system_dirs_len[0]))
548 ? NULL : (pelem + round_size));
552 while (idx < sizeof (system_dirs_len) / sizeof (system_dirs_len[0]));
554 max_dirnamelen = SYSTEM_DIRS_MAX_LEN;
558 /* This points to the map of the main object. */
562 assert (l->l_type != lt_loaded);
564 if (l->l_info[DT_RPATH])
565 /* Allocate room for the search path and fill in information
568 decompose_rpath ((const void *) (l->l_info[DT_STRTAB]->d_un.d_ptr
569 + l->l_info[DT_RPATH]->d_un.d_val),
572 l->l_rpath_dirs = NULL;
576 if (llp != NULL && *llp != '\0')
579 const char *cp = llp;
581 /* Decompose the LD_LIBRARY_PATH contents. First determine how many
586 if (*cp == ':' || *cp == ';')
591 env_path_list = (struct r_search_path_elem **)
592 malloc ((nllp + 1) * sizeof (struct r_search_path_elem *));
593 if (env_path_list == NULL)
594 _dl_signal_error (ENOMEM, NULL,
595 "cannot create cache for search path");
597 (void) fillin_rpath (local_strdup (llp), env_path_list, ":;",
598 __libc_enable_secure, "LD_LIBRARY_PATH", NULL);
603 /* Think twice before changing anything in this function. It is placed
604 here and prepared using the `alloca' magic to prevent it from being
605 inlined. The function is only called in case of an error. But then
606 performance does not count. The function used to be "inlinable" and
607 the compiled did so all the time. This increased the code size for
608 absolutely no good reason. */
609 #define LOSE(code, s) lose (code, fd, name, realname, l, s)
611 __attribute__ ((noreturn))
612 lose (int code, int fd, const char *name, char *realname, struct link_map *l,
615 /* The use of `alloca' here looks ridiculous but it helps. The goal
616 is to avoid the function from being inlined. There is no official
617 way to do this so we use this trick. gcc never inlines functions
618 which use `alloca'. */
619 int *a = alloca (sizeof (int));
621 (void) __close (a[0]);
624 /* Remove the stillborn object from the list and free it. */
626 l->l_prev->l_next = l->l_next;
628 l->l_next->l_prev = l->l_prev;
632 _dl_signal_error (code, name, msg);
636 /* Map in the shared object NAME, actually located in REALNAME, and already
639 #ifndef EXTERNAL_MAP_FROM_FD
643 _dl_map_object_from_fd (const char *name, int fd, char *realname,
644 struct link_map *loader, int l_type)
646 /* This is the expected ELF header. */
647 #define ELF32_CLASS ELFCLASS32
648 #define ELF64_CLASS ELFCLASS64
649 static const unsigned char expected[EI_PAD] =
655 [EI_CLASS] = ELFW(CLASS),
656 [EI_DATA] = byteorder,
657 [EI_VERSION] = EV_CURRENT,
658 [EI_OSABI] = ELFOSABI_SYSV,
661 struct link_map *l = NULL;
663 inline caddr_t map_segment (ElfW(Addr) mapstart, size_t len,
664 int prot, int fixed, off_t offset)
666 caddr_t mapat = __mmap ((caddr_t) mapstart, len, prot,
667 fixed|MAP_COPY|MAP_FILE,
669 if (mapat == MAP_FAILED)
670 LOSE (errno, "failed to map segment from shared object");
674 const ElfW(Ehdr) *header;
675 const ElfW(Phdr) *phdr;
676 const ElfW(Phdr) *ph;
683 /* Get file information. */
684 if (__fxstat (_STAT_VER, fd, &st) < 0)
685 LOSE (errno, "cannot stat shared object");
687 /* Look again to see if the real name matched another already loaded. */
688 for (l = _dl_loaded; l; l = l->l_next)
689 if (l->l_ino == st.st_ino && l->l_dev == st.st_dev)
691 /* The object is already loaded.
692 Just bump its reference count and return it. */
695 /* If the name is not in the list of names for this object add
698 add_name_to_object (l, name);
703 /* Print debugging message. */
705 _dl_debug_message (1, "file=", name, "; generating link map\n", NULL);
707 /* Read the header directly. */
708 readbuf = alloca (_dl_pagesize);
709 readlength = __libc_read (fd, readbuf, _dl_pagesize);
710 if (readlength < (ssize_t) sizeof (*header))
711 LOSE (errno, "cannot read file data");
712 header = (void *) readbuf;
714 /* Check the header for basic validity. */
715 if (memcmp (header->e_ident, expected, EI_PAD) != 0)
717 /* Something is wrong. */
718 if (*(Elf32_Word *) &header->e_ident !=
719 #if BYTE_ORDER == LITTLE_ENDIAN
720 ((ELFMAG0 << (EI_MAG0 * 8)) |
721 (ELFMAG1 << (EI_MAG1 * 8)) |
722 (ELFMAG2 << (EI_MAG2 * 8)) |
723 (ELFMAG3 << (EI_MAG3 * 8)))
725 ((ELFMAG0 << (EI_MAG3 * 8)) |
726 (ELFMAG1 << (EI_MAG2 * 8)) |
727 (ELFMAG2 << (EI_MAG1 * 8)) |
728 (ELFMAG3 << (EI_MAG0 * 8)))
731 LOSE (0, "invalid ELF header");
732 if (header->e_ident[EI_CLASS] != ELFW(CLASS))
733 LOSE (0, "ELF file class not " STRING(__ELF_NATIVE_CLASS) "-bit");
734 if (header->e_ident[EI_DATA] != byteorder)
735 LOSE (0, "ELF file data encoding not " byteorder_name);
736 if (header->e_ident[EI_VERSION] != EV_CURRENT)
737 LOSE (0, "ELF file version ident not " STRING(EV_CURRENT));
738 /* XXX We should be able so set system specific versions which are
740 if (header->e_ident[EI_OSABI] != ELFOSABI_SYSV)
741 LOSE (0, "ELF file OS ABI not " STRING(ELFOSABI_SYSV));
742 if (header->e_ident[EI_ABIVERSION] != 0)
743 LOSE (0, "ELF file ABI version not 0");
744 LOSE (0, "internal error");
747 if (header->e_version != EV_CURRENT)
748 LOSE (0, "ELF file version not " STRING(EV_CURRENT));
749 if (! elf_machine_matches_host (header->e_machine))
750 LOSE (0, "ELF file machine architecture not " ELF_MACHINE_NAME);
751 if (header->e_phentsize != sizeof (ElfW(Phdr)))
752 LOSE (0, "ELF file's phentsize not the expected size");
756 if (_dl_zerofd == -1)
758 _dl_zerofd = _dl_sysdep_open_zero_fill ();
759 if (_dl_zerofd == -1)
762 _dl_signal_error (errno, NULL, "cannot open zero fill device");
767 /* Enter the new object in the list of loaded objects. */
768 l = _dl_new_object (realname, name, l_type, loader);
770 LOSE (ENOMEM, "cannot create shared object descriptor");
773 /* Extract the remaining details we need from the ELF header
774 and then read in the program header table. */
775 l->l_entry = header->e_entry;
776 type = header->e_type;
777 l->l_phnum = header->e_phnum;
779 maplength = header->e_phnum * sizeof (ElfW(Phdr));
780 if (header->e_phoff + maplength <= readlength)
781 phdr = (void *) (readbuf + header->e_phoff);
784 phdr = alloca (maplength);
785 __lseek (fd, SEEK_SET, header->e_phoff);
786 if (__libc_read (fd, (void *) phdr, maplength) != maplength)
787 LOSE (errno, "cannot read file data");
791 /* Scan the program header table, collecting its load commands. */
794 ElfW(Addr) mapstart, mapend, dataend, allocend;
797 } loadcmds[l->l_phnum], *c;
798 size_t nloadcmds = 0;
800 /* The struct is initialized to zero so this is not necessary:
804 for (ph = phdr; ph < &phdr[l->l_phnum]; ++ph)
807 /* These entries tell us where to find things once the file's
808 segments are mapped in. We record the addresses it says
809 verbatim, and later correct for the run-time load address. */
811 l->l_ld = (void *) ph->p_vaddr;
814 l->l_phdr = (void *) ph->p_vaddr;
818 /* A load command tells us to map in part of the file.
819 We record the load commands and process them all later. */
820 if (ph->p_align % _dl_pagesize != 0)
821 LOSE (0, "ELF load command alignment not page-aligned");
822 if ((ph->p_vaddr - ph->p_offset) % ph->p_align)
823 LOSE (0, "ELF load command address/offset not properly aligned");
825 struct loadcmd *c = &loadcmds[nloadcmds++];
826 c->mapstart = ph->p_vaddr & ~(ph->p_align - 1);
827 c->mapend = ((ph->p_vaddr + ph->p_filesz + _dl_pagesize - 1)
828 & ~(_dl_pagesize - 1));
829 c->dataend = ph->p_vaddr + ph->p_filesz;
830 c->allocend = ph->p_vaddr + ph->p_memsz;
831 c->mapoff = ph->p_offset & ~(ph->p_align - 1);
833 /* Optimize a common case. */
834 if ((PF_R | PF_W | PF_X) == 7
835 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7)
836 c->prot = _dl_pf_to_prot[ph->p_flags & (PF_R | PF_W | PF_X)];
840 if (ph->p_flags & PF_R)
841 c->prot |= PROT_READ;
842 if (ph->p_flags & PF_W)
843 c->prot |= PROT_WRITE;
844 if (ph->p_flags & PF_X)
845 c->prot |= PROT_EXEC;
851 /* Now process the load commands and map segments into memory. */
854 /* Length of the sections to be loaded. */
855 maplength = loadcmds[nloadcmds - 1].allocend - c->mapstart;
857 if (type == ET_DYN || type == ET_REL)
859 /* This is a position-independent shared object. We can let the
860 kernel map it anywhere it likes, but we must have space for all
861 the segments in their specified positions relative to the first.
862 So we map the first segment without MAP_FIXED, but with its
863 extent increased to cover all the segments. Then we remove
864 access from excess portion, and there is known sufficient space
865 there to remap from the later segments.
867 As a refinement, sometimes we have an address that we would
868 prefer to map such objects at; but this is only a preference,
869 the OS can do whatever it likes. */
872 mappref = (ELF_PREFERRED_ADDRESS (loader, maplength, c->mapstart)
873 - MAP_BASE_ADDR (l));
874 mapat = map_segment (mappref, maplength, c->prot, 0, c->mapoff);
875 l->l_addr = (ElfW(Addr)) mapat - c->mapstart;
877 /* Change protection on the excess portion to disallow all access;
878 the portions we do not remap later will be inaccessible as if
879 unallocated. Then jump into the normal segment-mapping loop to
880 handle the portion of the segment past the end of the file
882 __mprotect ((caddr_t) (l->l_addr + c->mapend),
883 loadcmds[nloadcmds - 1].allocend - c->mapend,
886 /* Remember which part of the address space this object uses. */
887 l->l_map_start = c->mapstart + l->l_addr;
888 l->l_map_end = l->l_map_start + maplength;
894 /* Notify ELF_PREFERRED_ADDRESS that we have to load this one
896 ELF_FIXED_ADDRESS (loader, c->mapstart);
899 /* Remember which part of the address space this object uses. */
900 l->l_map_start = c->mapstart + l->l_addr;
901 l->l_map_end = l->l_map_start + maplength;
903 while (c < &loadcmds[nloadcmds])
905 if (c->mapend > c->mapstart)
906 /* Map the segment contents from the file. */
907 map_segment (l->l_addr + c->mapstart, c->mapend - c->mapstart,
908 c->prot, MAP_FIXED, c->mapoff);
911 if (c->allocend > c->dataend)
913 /* Extra zero pages should appear at the end of this segment,
914 after the data mapped from the file. */
915 ElfW(Addr) zero, zeroend, zeropage;
917 zero = l->l_addr + c->dataend;
918 zeroend = l->l_addr + c->allocend;
919 zeropage = (zero + _dl_pagesize - 1) & ~(_dl_pagesize - 1);
921 if (zeroend < zeropage)
922 /* All the extra data is in the last page of the segment.
923 We can just zero it. */
928 /* Zero the final part of the last page of the segment. */
929 if ((c->prot & PROT_WRITE) == 0)
932 if (__mprotect ((caddr_t) (zero & ~(_dl_pagesize - 1)),
933 _dl_pagesize, c->prot|PROT_WRITE) < 0)
934 LOSE (errno, "cannot change memory protections");
936 memset ((void *) zero, 0, zeropage - zero);
937 if ((c->prot & PROT_WRITE) == 0)
938 __mprotect ((caddr_t) (zero & ~(_dl_pagesize - 1)),
939 _dl_pagesize, c->prot);
942 if (zeroend > zeropage)
944 /* Map the remaining zero pages in from the zero fill FD. */
946 mapat = __mmap ((caddr_t) zeropage, zeroend - zeropage,
947 c->prot, MAP_ANON|MAP_PRIVATE|MAP_FIXED,
949 if (mapat == MAP_FAILED)
950 LOSE (errno, "cannot map zero-fill pages");
959 /* There was no PT_PHDR specified. We need to find the phdr in the
960 load image ourselves. We assume it is in fact in the load image
962 for (c = loadcmds; c < &loadcmds[nloadcmds]; c++)
963 if (c->mapoff <= header->e_phoff
964 && (c->mapend - c->mapstart + c->mapoff
965 >= header->e_phoff + header->e_phnum * sizeof (ElfW(Phdr))))
967 ElfW(Addr) bof = l->l_addr + c->mapstart;
968 l->l_phdr = (void *) (bof + header->e_phoff - c->mapoff);
972 LOSE (0, "program headers not contained in any loaded segment");
975 /* Adjust the PT_PHDR value by the runtime load address. */
976 (ElfW(Addr)) l->l_phdr += l->l_addr;
979 /* We are done mapping in the file. We no longer need the descriptor. */
982 if (l->l_type == lt_library && type == ET_EXEC)
983 l->l_type = lt_executable;
988 LOSE (0, "object file has no dynamic section");
991 (ElfW(Addr)) l->l_ld += l->l_addr;
993 l->l_entry += l->l_addr;
997 const size_t nibbles = sizeof (void *) * 2;
998 char buf1[nibbles + 1];
999 char buf2[nibbles + 1];
1000 char buf3[nibbles + 1];
1002 buf1[nibbles] = '\0';
1003 buf2[nibbles] = '\0';
1004 buf3[nibbles] = '\0';
1006 memset (buf1, '0', nibbles);
1007 memset (buf2, '0', nibbles);
1008 memset (buf3, '0', nibbles);
1009 _itoa_word ((unsigned long int) l->l_ld, &buf1[nibbles], 16, 0);
1010 _itoa_word ((unsigned long int) l->l_addr, &buf2[nibbles], 16, 0);
1011 _itoa_word (maplength, &buf3[nibbles], 16, 0);
1013 _dl_debug_message (1, " dynamic: 0x", buf1, " base: 0x", buf2,
1014 " size: 0x", buf3, "\n", NULL);
1015 memset (buf1, '0', nibbles);
1016 memset (buf2, '0', nibbles);
1017 memset (buf3, ' ', nibbles);
1018 _itoa_word ((unsigned long int) l->l_entry, &buf1[nibbles], 16, 0);
1019 _itoa_word ((unsigned long int) l->l_phdr, &buf2[nibbles], 16, 0);
1020 _itoa_word (l->l_phnum, &buf3[nibbles], 10, 0);
1021 _dl_debug_message (1, " entry: 0x", buf1, " phdr: 0x", buf2,
1022 " phnum: ", buf3, "\n\n", NULL);
1025 elf_get_dynamic_info (l->l_ld, l->l_addr, l->l_info);
1026 if (l->l_info[DT_HASH])
1029 /* If this object has DT_SYMBOLIC set modify now its scope. We don't
1030 have to do this for the main map. */
1031 if (l->l_info[DT_SYMBOLIC] && &l->l_searchlist != l->l_scope[0])
1033 /* Create an appropriate searchlist. It contains only this map.
1035 XXX This is the definition of DT_SYMBOLIC in SysVr4. The old
1036 GNU ld.so implementation had a different interpretation which
1037 is more reasonable. We are prepared to add this possibility
1038 back as part of a GNU extension of the ELF format. */
1039 l->l_symbolic_searchlist.r_list =
1040 (struct link_map **) malloc (sizeof (struct link_map *));
1042 if (l->l_symbolic_searchlist.r_list == NULL)
1043 LOSE (ENOMEM, "cannot create searchlist");
1045 l->l_symbolic_searchlist.r_list[0] = l;
1046 l->l_symbolic_searchlist.r_nlist = 1;
1047 l->l_symbolic_searchlist.r_duplist = l->l_symbolic_searchlist.r_list;
1048 l->l_symbolic_searchlist.r_nduplist = 1;
1050 /* Now move the existing entries one back. */
1051 memmove (&l->l_scope[1], &l->l_scope[0],
1052 sizeof (l->l_scope) - sizeof (l->l_scope[0]));
1054 /* Now add the new entry. */
1055 l->l_scope[0] = &l->l_symbolic_searchlist;
1058 /* Finally the file information. */
1059 l->l_dev = st.st_dev;
1060 l->l_ino = st.st_ino;
1065 /* Print search path. */
1067 print_search_path (struct r_search_path_elem **list,
1068 const char *what, const char *name)
1070 char buf[max_dirnamelen + max_capstrlen];
1073 _dl_debug_message (1, " search path=", NULL);
1075 while (*list != NULL && (*list)->what == what) /* Yes, ==. */
1077 char *endp = __mempcpy (buf, (*list)->dirname, (*list)->dirnamelen);
1080 for (cnt = 0; cnt < ncapstr; ++cnt)
1081 if ((*list)->status[cnt] != nonexisting)
1083 char *cp = __mempcpy (endp, capstr[cnt].str, capstr[cnt].len);
1084 if (cp == buf || (cp == buf + 1 && buf[0] == '/'))
1088 _dl_debug_message (0, first ? "" : ":", buf, NULL);
1096 _dl_debug_message (0, "\t\t(", what, " from file ",
1097 name[0] ? name : _dl_argv[0], ")\n", NULL);
1099 _dl_debug_message (0, "\t\t(", what, ")\n", NULL);
1102 /* Try to open NAME in one of the directories in DIRS.
1103 Return the fd, or -1. If successful, fill in *REALNAME
1104 with the malloc'd full directory name. */
1107 open_path (const char *name, size_t namelen, int preloaded,
1108 struct r_search_path_elem **dirs,
1113 const char *current_what = NULL;
1115 if (dirs == NULL || *dirs == NULL)
1117 __set_errno (ENOENT);
1121 buf = alloca (max_dirnamelen + max_capstrlen + namelen);
1124 struct r_search_path_elem *this_dir = *dirs;
1129 /* If we are debugging the search for libraries print the path
1130 now if it hasn't happened now. */
1131 if (_dl_debug_libs && current_what != this_dir->what)
1133 current_what = this_dir->what;
1134 print_search_path (dirs, current_what, this_dir->where);
1137 edp = (char *) __mempcpy (buf, this_dir->dirname, this_dir->dirnamelen);
1138 for (cnt = 0; fd == -1 && cnt < ncapstr; ++cnt)
1140 /* Skip this directory if we know it does not exist. */
1141 if (this_dir->status[cnt] == nonexisting)
1145 ((char *) __mempcpy (__mempcpy (edp,
1146 capstr[cnt].str, capstr[cnt].len),
1150 /* Print name we try if this is wanted. */
1152 _dl_debug_message (1, " trying file=", buf, "\n", NULL);
1154 fd = __open (buf, O_RDONLY);
1155 if (this_dir->status[cnt] == unknown)
1158 this_dir->status[cnt] = existing;
1161 /* We failed to open machine dependent library. Let's
1162 test whether there is any directory at all. */
1165 buf[buflen - namelen - 1] = '\0';
1167 if (__xstat (_STAT_VER, buf, &st) != 0
1168 || ! S_ISDIR (st.st_mode))
1169 /* The directory does not exist or it is no directory. */
1170 this_dir->status[cnt] = nonexisting;
1172 this_dir->status[cnt] = existing;
1176 if (fd != -1 && preloaded && __libc_enable_secure)
1178 /* This is an extra security effort to make sure nobody can
1179 preload broken shared objects which are in the trusted
1180 directories and so exploit the bugs. */
1183 if (__fxstat (_STAT_VER, fd, &st) != 0
1184 || (st.st_mode & S_ISUID) == 0)
1186 /* The shared object cannot be tested for being SUID
1187 or this bit is not set. In this case we must not
1191 /* We simply ignore the file, signal this by setting
1192 the error value which would have been set by `open'. */
1200 *realname = malloc (buflen);
1201 if (*realname != NULL)
1203 memcpy (*realname, buf, buflen);
1208 /* No memory for the name, we certainly won't be able
1209 to load and link it. */
1214 if (errno != ENOENT && errno != EACCES)
1215 /* The file exists and is readable, but something went wrong. */
1218 while (*++dirs != NULL);
1223 /* Map in the shared object file NAME. */
1227 _dl_map_object (struct link_map *loader, const char *name, int preloaded,
1228 int type, int trace_mode)
1235 /* Look for this name among those already loaded. */
1236 for (l = _dl_loaded; l; l = l->l_next)
1238 /* If the requested name matches the soname of a loaded object,
1239 use that object. Elide this check for names that have not
1241 if (l->l_opencount <= 0)
1243 if (!_dl_name_match_p (name, l))
1247 if (l->l_info[DT_SONAME] == NULL)
1250 soname = (const void *) (l->l_info[DT_STRTAB]->d_un.d_ptr
1251 + l->l_info[DT_SONAME]->d_un.d_val);
1252 if (strcmp (name, soname) != 0)
1255 /* We have a match on a new name -- cache it. */
1256 add_name_to_object (l, soname);
1259 /* We have a match -- bump the reference count and return it. */
1264 /* Display information if we are debugging. */
1265 if (_dl_debug_files && loader != NULL)
1266 _dl_debug_message (1, "\nfile=", name, "; needed by ",
1267 loader->l_name[0] ? loader->l_name : _dl_argv[0],
1270 if (strchr (name, '/') == NULL)
1272 /* Search for NAME in several places. */
1274 size_t namelen = strlen (name) + 1;
1277 _dl_debug_message (1, "find library=", name, "; searching\n", NULL);
1281 /* First try the DT_RPATH of the dependent object that caused NAME
1282 to be loaded. Then that object's dependent, and on up. */
1283 for (l = loader; fd == -1 && l; l = l->l_loader)
1284 if (l->l_info[DT_RPATH])
1286 /* Make sure the cache information is available. */
1287 if (l->l_rpath_dirs == NULL)
1289 size_t ptrval = (l->l_info[DT_STRTAB]->d_un.d_ptr
1290 + l->l_info[DT_RPATH]->d_un.d_val);
1292 decompose_rpath ((const char *) ptrval, l);
1295 if (l->l_rpath_dirs != NULL)
1296 fd = open_path (name, namelen, preloaded, l->l_rpath_dirs,
1300 /* If dynamically linked, try the DT_RPATH of the executable itself. */
1302 if (fd == -1 && l && l->l_type != lt_loaded && l != loader
1303 && l->l_rpath_dirs != NULL)
1304 fd = open_path (name, namelen, preloaded, l->l_rpath_dirs, &realname);
1306 /* Try the LD_LIBRARY_PATH environment variable. */
1307 if (fd == -1 && env_path_list != NULL)
1308 fd = open_path (name, namelen, preloaded, env_path_list, &realname);
1312 /* Check the list of libraries in the file /etc/ld.so.cache,
1313 for compatibility with Linux's ldconfig program. */
1314 extern const char *_dl_load_cache_lookup (const char *name);
1315 const char *cached = _dl_load_cache_lookup (name);
1318 fd = __open (cached, O_RDONLY);
1321 realname = local_strdup (cached);
1322 if (realname == NULL)
1331 /* Finally, try the default path. */
1333 fd = open_path (name, namelen, preloaded, rtld_search_dirs, &realname);
1335 /* Add another newline when we a tracing the library loading. */
1337 _dl_debug_message (1, "\n", NULL);
1341 /* The path may contain dynamic string tokens. */
1343 ? expand_dynamic_string_token (loader, name)
1344 : local_strdup (name));
1345 if (realname == NULL)
1349 fd = __open (realname, O_RDONLY);
1359 /* We haven't found an appropriate library. But since we
1360 are only interested in the list of libraries this isn't
1361 so severe. Fake an entry with all the information we
1363 static const ElfW(Symndx) dummy_bucket = STN_UNDEF;
1365 /* Enter the new object in the list of loaded objects. */
1366 if ((name_copy = local_strdup (name)) == NULL
1367 || (l = _dl_new_object (name_copy, name, type, loader)) == NULL)
1368 _dl_signal_error (ENOMEM, name,
1369 "cannot create shared object descriptor");
1370 /* We use an opencount of 0 as a sign for the faked entry.
1371 Since the descriptor is initialized with zero we do not
1374 l->l_reserved = 0; */
1375 l->l_buckets = &dummy_bucket;
1382 _dl_signal_error (errno, name, "cannot open shared object file");
1385 return _dl_map_object_from_fd (name, fd, realname, loader, type);