1 /* ELF emulation code for targets using elf.em.
2 Copyright (C) 1991-2024 Free Software Foundation, Inc.
4 This file is part of the GNU Binutils.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
19 MA 02110-1301, USA. */
23 #include "libiberty.h"
24 #include "filenames.h"
25 #include "safe-ctype.h"
35 #include "ldbuildid.h"
52 /* Style of .note.gnu.build-id section. */
53 const char *ldelf_emit_note_gnu_build_id
;
55 /* Content of .note.package section. */
56 const char *ldelf_emit_note_fdo_package_metadata
;
58 /* These variables are required to pass information back and forth
59 between after_open and check_needed and stat_needed and vercheck. */
61 static struct bfd_link_needed_list
*global_needed
;
62 static lang_input_statement_type
*global_found
;
63 static struct stat global_stat
;
64 static struct bfd_link_needed_list
*global_vercheck_needed
;
65 static bool global_vercheck_failed
;
68 ldelf_after_parse (void)
70 if (bfd_link_pie (&link_info
))
71 link_info
.flags_1
|= (bfd_vma
) DF_1_PIE
;
73 if (bfd_link_executable (&link_info
)
74 && link_info
.nointerp
)
76 if (link_info
.dynamic_undefined_weak
> 0)
77 queue_unknown_cmdline_warning ("-z dynamic-undefined-weak");
78 link_info
.dynamic_undefined_weak
= 0;
81 /* Disable DT_RELR if not building PIE nor shared library. */
82 if (!bfd_link_pic (&link_info
))
83 link_info
.enable_dt_relr
= 0;
85 /* Add 3 spare tags for DT_RELR, DT_RELRSZ and DT_RELRENT. */
86 if (link_info
.enable_dt_relr
)
87 link_info
.spare_dynamic_tags
+= 3;
89 after_parse_default ();
90 if (link_info
.commonpagesize
> link_info
.maxpagesize
)
92 if (!link_info
.commonpagesize_is_set
)
93 link_info
.commonpagesize
= link_info
.maxpagesize
;
94 else if (!link_info
.maxpagesize_is_set
)
95 link_info
.maxpagesize
= link_info
.commonpagesize
;
97 einfo (_("%F%P: common page size (0x%v) > maximum page size (0x%v)\n"),
98 link_info
.commonpagesize
, link_info
.maxpagesize
);
102 /* Handle the generation of DT_NEEDED tags. */
105 ldelf_load_symbols (lang_input_statement_type
*entry
)
109 /* Tell the ELF linker that we don't want the output file to have a
110 DT_NEEDED entry for this file, unless it is used to resolve
111 references in a regular object. */
112 if (entry
->flags
.add_DT_NEEDED_for_regular
)
113 link_class
= DYN_AS_NEEDED
;
115 /* Tell the ELF linker that we don't want the output file to have a
116 DT_NEEDED entry for any dynamic library in DT_NEEDED tags from
118 if (!entry
->flags
.add_DT_NEEDED_for_dynamic
)
119 link_class
|= DYN_NO_ADD_NEEDED
;
121 if (entry
->flags
.just_syms
122 && (bfd_get_file_flags (entry
->the_bfd
) & DYNAMIC
) != 0)
123 einfo (_("%F%P: %pB: --just-symbols may not be used on DSO\n"),
127 || (bfd_get_file_flags (entry
->the_bfd
) & DYNAMIC
) == 0)
130 bfd_elf_set_dyn_lib_class (entry
->the_bfd
,
131 (enum dynamic_lib_link_class
) link_class
);
133 /* Continue on with normal load_symbols processing. */
137 /* On Linux, it's possible to have different versions of the same
138 shared library linked against different versions of libc. The
139 dynamic linker somehow tags which libc version to use in
140 /etc/ld.so.cache, and, based on the libc that it sees in the
141 executable, chooses which version of the shared library to use.
143 We try to do a similar check here by checking whether this shared
144 library needs any other shared libraries which may conflict with
145 libraries we have already included in the link. If it does, we
146 skip it, and try to find another shared library farther on down the
149 This is called via lang_for_each_input_file.
150 GLOBAL_VERCHECK_NEEDED is the list of objects needed by the object
151 which we are checking. This sets GLOBAL_VERCHECK_FAILED if we find
152 a conflicting version. */
155 ldelf_vercheck (lang_input_statement_type
*s
)
158 struct bfd_link_needed_list
*l
;
160 if (global_vercheck_failed
)
162 if (s
->the_bfd
== NULL
163 || (bfd_get_file_flags (s
->the_bfd
) & DYNAMIC
) == 0)
166 soname
= bfd_elf_get_dt_soname (s
->the_bfd
);
168 soname
= lbasename (bfd_get_filename (s
->the_bfd
));
170 for (l
= global_vercheck_needed
; l
!= NULL
; l
= l
->next
)
174 if (filename_cmp (soname
, l
->name
) == 0)
176 /* Probably can't happen, but it's an easy check. */
180 if (strchr (l
->name
, '/') != NULL
)
183 suffix
= strstr (l
->name
, ".so.");
187 suffix
+= sizeof ".so." - 1;
189 if (filename_ncmp (soname
, l
->name
, suffix
- l
->name
) == 0)
191 /* Here we know that S is a dynamic object FOO.SO.VER1, and
192 the object we are considering needs a dynamic object
193 FOO.SO.VER2, and VER1 and VER2 are different. This
194 appears to be a version mismatch, so we tell the caller
195 to try a different version of this library. */
196 global_vercheck_failed
= true;
203 /* See if an input file matches a DT_NEEDED entry by running stat on
207 ldelf_stat_needed (lang_input_statement_type
*s
)
213 if (global_found
!= NULL
)
215 if (s
->the_bfd
== NULL
)
218 /* If this input file was an as-needed entry, and wasn't found to be
219 needed at the stage it was linked, then don't say we have loaded it. */
220 if ((bfd_elf_get_dyn_lib_class (s
->the_bfd
) & DYN_AS_NEEDED
) != 0)
223 if (bfd_stat (s
->the_bfd
, &st
) != 0)
225 einfo (_("%P: %pB: bfd_stat failed: %E\n"), s
->the_bfd
);
229 /* Some operating systems, e.g. Windows, do not provide a meaningful
230 st_ino; they always set it to zero. (Windows does provide a
231 meaningful st_dev.) Do not indicate a duplicate library in that
232 case. While there is no guarantee that a system that provides
233 meaningful inode numbers will never set st_ino to zero, this is
234 merely an optimization, so we do not need to worry about false
236 if (st
.st_dev
== global_stat
.st_dev
237 && st
.st_ino
== global_stat
.st_ino
244 /* We issue a warning if it looks like we are including two
245 different versions of the same shared library. For example,
246 there may be a problem if -lc picks up libc.so.6 but some other
247 shared library has a DT_NEEDED entry of libc.so.5. This is a
248 heuristic test, and it will only work if the name looks like
249 NAME.so.VERSION. FIXME: Depending on file names is error-prone.
250 If we really want to issue warnings about mixing version numbers
251 of shared libraries, we need to find a better way. */
253 if (strchr (global_needed
->name
, '/') != NULL
)
255 suffix
= strstr (global_needed
->name
, ".so.");
258 suffix
+= sizeof ".so." - 1;
260 soname
= bfd_elf_get_dt_soname (s
->the_bfd
);
262 soname
= lbasename (s
->filename
);
264 if (filename_ncmp (soname
, global_needed
->name
,
265 suffix
- global_needed
->name
) == 0)
266 einfo (_("%P: warning: %s, needed by %pB, may conflict with %s\n"),
267 global_needed
->name
, global_needed
->by
, soname
);
270 /* This function is called for each possible name for a dynamic object
271 named by a DT_NEEDED entry. The FORCE parameter indicates whether
272 to skip the check for a conflicting version. */
275 ldelf_try_needed (struct dt_needed
*needed
, int force
, int is_linux
)
278 const char *name
= needed
->name
;
282 abfd
= bfd_openr (name
, bfd_get_target (link_info
.output_bfd
));
286 info_msg (_("attempt to open %s failed\n"), name
);
290 track_dependency_files (name
);
292 /* Linker needs to decompress sections. */
293 abfd
->flags
|= BFD_DECOMPRESS
;
295 if (! bfd_check_format (abfd
, bfd_object
))
300 if ((bfd_get_file_flags (abfd
) & DYNAMIC
) == 0)
306 /* For DT_NEEDED, they have to match. */
307 if (abfd
->xvec
!= link_info
.output_bfd
->xvec
)
313 /* Check whether this object would include any conflicting library
314 versions. If FORCE is set, then we skip this check; we use this
315 the second time around, if we couldn't find any compatible
316 instance of the shared library. */
320 struct bfd_link_needed_list
*needs
;
322 if (! bfd_elf_get_bfd_needed_list (abfd
, &needs
))
323 einfo (_("%F%P: %pB: bfd_elf_get_bfd_needed_list failed: %E\n"), abfd
);
327 global_vercheck_needed
= needs
;
328 global_vercheck_failed
= false;
329 lang_for_each_input_file (ldelf_vercheck
);
330 if (global_vercheck_failed
)
333 /* Return FALSE to force the caller to move on to try
334 another file on the search path. */
338 /* But wait! It gets much worse. On Linux, if a shared
339 library does not use libc at all, we are supposed to skip
340 it the first time around in case we encounter a shared
341 library later on with the same name which does use the
342 version of libc that we want. This is much too horrible
343 to use on any system other than Linux. */
346 struct bfd_link_needed_list
*l
;
348 for (l
= needs
; l
!= NULL
; l
= l
->next
)
349 if (startswith (l
->name
, "libc.so"))
360 /* We've found a dynamic object matching the DT_NEEDED entry. */
362 /* We have already checked that there is no other input file of the
363 same name. We must now check again that we are not including the
364 same file twice. We need to do this because on many systems
365 libc.so is a symlink to, e.g., libc.so.1. The SONAME entry will
366 reference libc.so.1. If we have already included libc.so, we
367 don't want to include libc.so.1 if they are the same file, and we
368 can only check that using stat. */
370 if (bfd_stat (abfd
, &global_stat
) != 0)
371 einfo (_("%F%P: %pB: bfd_stat failed: %E\n"), abfd
);
373 /* First strip off everything before the last '/'. */
374 soname
= lbasename (bfd_get_filename (abfd
));
377 info_msg (_("found %s at %s\n"), soname
, name
);
380 lang_for_each_input_file (ldelf_stat_needed
);
381 if (global_found
!= NULL
)
383 /* Return TRUE to indicate that we found the file, even though
384 we aren't going to do anything with it. */
388 /* Specify the soname to use. */
389 bfd_elf_set_dt_needed_name (abfd
, soname
);
391 /* Tell the ELF linker that we don't want the output file to have a
392 DT_NEEDED entry for this file, unless it is used to resolve
393 references in a regular object. */
394 link_class
= DYN_DT_NEEDED
;
396 /* Tell the ELF linker that we don't want the output file to have a
397 DT_NEEDED entry for this file at all if the entry is from a file
398 with DYN_NO_ADD_NEEDED. */
399 if (needed
->by
!= NULL
400 && (bfd_elf_get_dyn_lib_class (needed
->by
) & DYN_NO_ADD_NEEDED
) != 0)
401 link_class
|= DYN_NO_NEEDED
| DYN_NO_ADD_NEEDED
;
403 bfd_elf_set_dyn_lib_class (abfd
, (enum dynamic_lib_link_class
) link_class
);
405 *link_info
.input_bfds_tail
= abfd
;
406 link_info
.input_bfds_tail
= &abfd
->link
.next
;
408 /* Add this file into the symbol table. */
409 if (! bfd_link_add_symbols (abfd
, &link_info
))
410 einfo (_("%F%P: %pB: error adding symbols: %E\n"), abfd
);
415 /* Search for a needed file in a path. */
418 ldelf_search_needed (const char *path
, struct dt_needed
*n
, int force
,
419 int is_linux
, int elfsize
)
422 const char *name
= n
->name
;
424 struct dt_needed needed
;
427 return ldelf_try_needed (n
, force
, is_linux
);
429 if (path
== NULL
|| *path
== '\0')
433 needed
.name
= n
->name
;
440 char *filename
, *sset
;
442 s
= strchr (path
, config
.rpath_separator
);
444 s
= path
+ strlen (path
);
446 #if HAVE_DOS_BASED_FILE_SYSTEM
447 /* Assume a match on the second char is part of drive specifier. */
448 else if (config
.rpath_separator
== ':'
452 s
= strchr (s
+ 1, config
.rpath_separator
);
454 s
= path
+ strlen (path
);
457 filename
= (char *) xmalloc (s
- path
+ len
+ 2);
462 memcpy (filename
, path
, s
- path
);
463 filename
[s
- path
] = '/';
464 sset
= filename
+ (s
- path
) + 1;
468 /* PR 20535: Support the same pseudo-environment variables that
469 are supported by ld.so. Namely, $ORIGIN, $LIB and $PLATFORM.
470 Since there can be more than one occurrence of these tokens in
471 the path we loop until no more are found. Since we might not
472 be able to substitute some of the tokens we maintain an offset
473 into the filename for where we should begin our scan. */
474 while ((var
= strchr (filename
+ offset
, '$')) != NULL
)
476 /* The ld.so manual page does not say, but I am going to assume that
477 these tokens are terminated by a directory separator character
478 (/) or the end of the string. There is also an implication that
479 $ORIGIN should only be used at the start of a path, but that is
482 The ld.so manual page also states that it allows ${ORIGIN},
483 ${LIB} and ${PLATFORM}, so these are supported as well.
485 FIXME: The code could be a lot cleverer about allocating space
486 for the processed string. */
487 char * end
= strchr (var
, '/');
488 const char *replacement
= NULL
;
490 char * freeme
= NULL
;
491 unsigned flen
= strlen (filename
);
494 /* Temporarily terminate the filename at the end of the token. */
502 if (strcmp (v
, "RIGIN") == 0 || strcmp (v
, "RIGIN}") == 0)
504 /* ORIGIN - replace with the full path to the directory
505 containing the program or shared object. */
506 if (needed
.by
== NULL
)
508 if (link_info
.output_bfd
== NULL
)
513 replacement
= bfd_get_filename (link_info
.output_bfd
);
516 replacement
= bfd_get_filename (needed
.by
);
522 if (replacement
[0] == '/')
523 freeme
= xstrdup (replacement
);
526 char * current_dir
= getpwd ();
527 size_t cdir_len
= strlen (current_dir
);
528 size_t rep_len
= strlen (replacement
);
529 freeme
= xmalloc (cdir_len
+ rep_len
+ 2);
530 memcpy (freeme
, current_dir
, cdir_len
);
531 freeme
[cdir_len
] = '/';
532 memcpy (freeme
+ cdir_len
+ 1,
533 replacement
, rep_len
+ 1);
536 replacement
= freeme
;
537 if ((slash
= strrchr (replacement
, '/')) != NULL
)
544 if (strcmp (v
, "IB") == 0 || strcmp (v
, "IB}") == 0)
546 /* LIB - replace with "lib" in 32-bit environments
547 and "lib64" in 64-bit environments. */
551 case 32: replacement
= "lib"; break;
552 case 64: replacement
= "lib64"; break;
560 /* Supporting $PLATFORM in a cross-hosted environment is not
561 possible. Supporting it in a native environment involves
562 loading the <sys/auxv.h> header file which loads the
563 system <elf.h> header file, which conflicts with the
564 "include/elf/mips.h" header file. */
572 char * filename2
= xmalloc (flen
+ strlen (replacement
));
576 sprintf (filename2
, "%.*s%s/%s",
577 (int)(var
- filename
), filename
,
578 replacement
, end
+ 1);
579 offset
= (var
- filename
) + 1 + strlen (replacement
);
583 sprintf (filename2
, "%.*s%s",
584 (int)(var
- filename
), filename
,
586 offset
= var
- filename
+ strlen (replacement
);
590 filename
= filename2
;
591 /* There is no need to restore the path separator (when
592 end != NULL) as we have replaced the entire string. */
597 /* We only issue an "unrecognised" message in verbose mode
598 as the $<foo> token might be a legitimate component of
599 a path name in the target's file system. */
600 info_msg (_("unrecognised or unsupported token "
601 "'%s' in search path\n"), var
);
603 /* Restore the path separator. */
606 /* PR 20784: Make sure that we resume the scan *after*
607 the token that we could not replace. */
608 offset
= (var
+ 1) - filename
;
614 needed
.name
= filename
;
616 if (ldelf_try_needed (&needed
, force
, is_linux
))
629 /* Prefix the sysroot to absolute paths in PATH, a string containing
630 paths separated by config.rpath_separator. If running on a DOS
631 file system, paths containing a drive spec won't have the sysroot
632 prefix added, unless the sysroot also specifies the same drive. */
635 ldelf_add_sysroot (const char *path
)
640 int dos_drive_sysroot
= HAS_DRIVE_SPEC (ld_sysroot
);
642 len
= strlen (ld_sysroot
);
643 for (extra
= 0, p
= path
; ; )
645 int dos_drive
= HAS_DRIVE_SPEC (p
);
649 if (IS_DIR_SEPARATOR (*p
)
651 || (dos_drive_sysroot
652 && ld_sysroot
[0] == p
[-2])))
654 if (dos_drive
&& dos_drive_sysroot
)
659 p
= strchr (p
, config
.rpath_separator
);
665 ret
= xmalloc (strlen (path
) + extra
+ 1);
667 for (q
= ret
, p
= path
; ; )
670 int dos_drive
= HAS_DRIVE_SPEC (p
);
677 if (IS_DIR_SEPARATOR (*p
)
679 || (dos_drive_sysroot
680 && ld_sysroot
[0] == p
[-2])))
682 if (dos_drive
&& dos_drive_sysroot
)
684 strcpy (q
, ld_sysroot
+ 2);
689 strcpy (q
, ld_sysroot
);
693 end
= strchr (p
, config
.rpath_separator
);
696 size_t n
= end
- p
+ 1;
711 /* Read the system search path the FreeBSD way rather than the Linux way. */
712 #ifdef HAVE_ELF_HINTS_H
713 #include <elf-hints.h>
715 #include "elf-hints-local.h"
719 ldelf_check_ld_elf_hints (const struct bfd_link_needed_list
*l
, int force
,
722 static bool initialized
;
723 static const char *ld_elf_hints
;
724 struct dt_needed needed
;
731 tmppath
= concat (ld_sysroot
, _PATH_ELF_HINTS
, (const char *) NULL
);
732 f
= fopen (tmppath
, FOPEN_RB
);
736 struct elfhints_hdr hdr
;
738 if (fread (&hdr
, 1, sizeof (hdr
), f
) == sizeof (hdr
)
739 && hdr
.magic
== ELFHINTS_MAGIC
742 if (fseek (f
, hdr
.strtab
+ hdr
.dirlist
, SEEK_SET
) != -1)
746 b
= xmalloc (hdr
.dirlistlen
+ 1);
747 if (fread (b
, 1, hdr
.dirlistlen
+ 1, f
) ==
749 ld_elf_hints
= ldelf_add_sysroot (b
);
760 if (ld_elf_hints
== NULL
)
764 needed
.name
= l
->name
;
765 return ldelf_search_needed (ld_elf_hints
, &needed
, force
, false, elfsize
);
768 /* For a native linker, check the file /etc/ld.so.conf for directories
769 in which we may find shared libraries. /etc/ld.so.conf is really
770 only meaningful on Linux. */
772 struct ldelf_ld_so_conf
779 ldelf_parse_ld_so_conf (struct ldelf_ld_so_conf
*, const char *);
782 ldelf_parse_ld_so_conf_include (struct ldelf_ld_so_conf
*info
,
783 const char *filename
,
791 if (pattern
[0] != '/')
793 char *p
= strrchr (filename
, '/');
794 size_t patlen
= strlen (pattern
) + 1;
796 newp
= xmalloc (p
- filename
+ 1 + patlen
);
797 memcpy (newp
, filename
, p
- filename
+ 1);
798 memcpy (newp
+ (p
- filename
+ 1), pattern
, patlen
);
803 if (glob (pattern
, 0, NULL
, &gl
) == 0)
807 for (i
= 0; i
< gl
.gl_pathc
; ++i
)
808 ldelf_parse_ld_so_conf (info
, gl
.gl_pathv
[i
]);
812 /* If we do not have glob, treat the pattern as a literal filename. */
813 ldelf_parse_ld_so_conf (info
, pattern
);
820 ldelf_parse_ld_so_conf (struct ldelf_ld_so_conf
*info
, const char *filename
)
822 FILE *f
= fopen (filename
, FOPEN_RT
);
830 line
= xmalloc (linelen
);
835 /* Normally this would use getline(3), but we need to be portable. */
836 while ((q
= fgets (p
, linelen
- (p
- line
), f
)) != NULL
837 && strlen (q
) == linelen
- (p
- line
) - 1
838 && line
[linelen
- 2] != '\n')
840 line
= xrealloc (line
, 2 * linelen
);
841 p
= line
+ linelen
- 1;
845 if (q
== NULL
&& p
== line
)
848 p
= strchr (line
, '\n');
852 /* Because the file format does not know any form of quoting we
853 can search forward for the next '#' character and if found
854 make it terminating the line. */
855 p
= strchr (line
, '#');
859 /* Remove leading whitespace. NUL is no whitespace character. */
861 while (*p
== ' ' || *p
== '\f' || *p
== '\r' || *p
== '\t' || *p
== '\v')
864 /* If the line is blank it is ignored. */
868 if (startswith (p
, "include") && (p
[7] == ' ' || p
[7] == '\t'))
874 while (*p
== ' ' || *p
== '\t')
882 while (*p
!= ' ' && *p
!= '\t' && *p
)
888 ldelf_parse_ld_so_conf_include (info
, filename
, dir
);
895 while (*p
&& *p
!= '=' && *p
!= ' ' && *p
!= '\t' && *p
!= '\f'
896 && *p
!= '\r' && *p
!= '\v')
899 while (p
!= dir
&& p
[-1] == '/')
901 if (info
->path
== NULL
)
903 info
->alloc
= p
- dir
+ 1 + 256;
904 info
->path
= xmalloc (info
->alloc
);
909 if (info
->len
+ 1 + (p
- dir
) >= info
->alloc
)
911 info
->alloc
+= p
- dir
+ 256;
912 info
->path
= xrealloc (info
->path
, info
->alloc
);
914 info
->path
[info
->len
++] = config
.rpath_separator
;
916 memcpy (info
->path
+ info
->len
, dir
, p
- dir
);
917 info
->len
+= p
- dir
;
918 info
->path
[info
->len
] = '\0';
928 ldelf_check_ld_so_conf (const struct bfd_link_needed_list
*l
, int force
,
929 int elfsize
, const char *prefix
)
931 static bool initialized
;
932 static const char *ld_so_conf
;
933 struct dt_needed needed
;
938 struct ldelf_ld_so_conf info
;
941 info
.len
= info
.alloc
= 0;
942 tmppath
= concat (ld_sysroot
, prefix
, "/etc/ld.so.conf",
943 (const char *) NULL
);
944 if (!ldelf_parse_ld_so_conf (&info
, tmppath
))
947 tmppath
= concat (ld_sysroot
, "/etc/ld.so.conf",
948 (const char *) NULL
);
949 ldelf_parse_ld_so_conf (&info
, tmppath
);
955 ld_so_conf
= ldelf_add_sysroot (info
.path
);
961 if (ld_so_conf
== NULL
)
966 needed
.name
= l
->name
;
967 return ldelf_search_needed (ld_so_conf
, &needed
, force
, true, elfsize
);
970 /* See if an input file matches a DT_NEEDED entry by name. */
973 ldelf_check_needed (lang_input_statement_type
*s
)
977 /* Stop looking if we've found a loaded lib. */
978 if (global_found
!= NULL
979 && (bfd_elf_get_dyn_lib_class (global_found
->the_bfd
)
980 & DYN_AS_NEEDED
) == 0)
983 if (s
->filename
== NULL
|| s
->the_bfd
== NULL
)
986 /* Don't look for a second non-loaded as-needed lib. */
987 if (global_found
!= NULL
988 && (bfd_elf_get_dyn_lib_class (s
->the_bfd
) & DYN_AS_NEEDED
) != 0)
991 if (filename_cmp (s
->filename
, global_needed
->name
) == 0)
997 if (s
->flags
.search_dirs
)
999 const char *f
= strrchr (s
->filename
, '/');
1001 && filename_cmp (f
+ 1, global_needed
->name
) == 0)
1008 soname
= bfd_elf_get_dt_soname (s
->the_bfd
);
1010 && filename_cmp (soname
, global_needed
->name
) == 0)
1018 ldelf_handle_dt_needed (struct elf_link_hash_table
*htab
,
1019 int use_libpath
, int native
, int is_linux
,
1020 int is_freebsd
, int elfsize
, const char *prefix
)
1022 struct bfd_link_needed_list
*needed
, *l
;
1024 bfd
**save_input_bfd_tail
;
1026 /* Get the list of files which appear in DT_NEEDED entries in
1027 dynamic objects included in the link (often there will be none).
1028 For each such file, we want to track down the corresponding
1029 library, and include the symbol table in the link. This is what
1030 the runtime dynamic linker will do. Tracking the files down here
1031 permits one dynamic object to include another without requiring
1032 special action by the person doing the link. Note that the
1033 needed list can actually grow while we are stepping through this
1035 save_input_bfd_tail
= link_info
.input_bfds_tail
;
1036 needed
= bfd_elf_get_needed_list (link_info
.output_bfd
, &link_info
);
1037 for (l
= needed
; l
!= NULL
; l
= l
->next
)
1039 struct bfd_link_needed_list
*ll
;
1040 struct dt_needed n
, nn
;
1043 /* If the lib that needs this one was --as-needed and wasn't
1044 found to be needed, then this lib isn't needed either. */
1046 && (bfd_elf_get_dyn_lib_class (l
->by
) & DYN_AS_NEEDED
) != 0)
1049 /* Skip the lib if --no-copy-dt-needed-entries and when we are
1050 handling DT_NEEDED entries or --allow-shlib-undefined is in
1053 && (htab
->handling_dt_needed
1054 || link_info
.unresolved_syms_in_shared_libs
== RM_IGNORE
)
1055 && (bfd_elf_get_dyn_lib_class (l
->by
) & DYN_NO_ADD_NEEDED
) != 0)
1058 /* If we've already seen this file, skip it. */
1059 for (ll
= needed
; ll
!= l
; ll
= ll
->next
)
1061 || (bfd_elf_get_dyn_lib_class (ll
->by
) & DYN_AS_NEEDED
) == 0)
1062 && strcmp (ll
->name
, l
->name
) == 0)
1067 /* See if this file was included in the link explicitly. */
1069 global_found
= NULL
;
1070 lang_for_each_input_file (ldelf_check_needed
);
1071 if (global_found
!= NULL
1072 && (bfd_elf_get_dyn_lib_class (global_found
->the_bfd
)
1073 & DYN_AS_NEEDED
) == 0)
1080 info_msg (_("%s needed by %pB\n"), l
->name
, l
->by
);
1082 /* As-needed libs specified on the command line (or linker script)
1083 take priority over libs found in search dirs. */
1084 if (global_found
!= NULL
)
1086 nn
.name
= global_found
->filename
;
1087 if (ldelf_try_needed (&nn
, true, is_linux
))
1091 /* We need to find this file and include the symbol table. We
1092 want to search for the file in the same way that the dynamic
1093 linker will search. That means that we want to use
1094 rpath_link, rpath, then the environment variable
1095 LD_LIBRARY_PATH (native only), then the DT_RPATH/DT_RUNPATH
1096 entries (native only), then the linker script LIB_SEARCH_DIRS.
1097 We do not search using the -L arguments.
1099 We search twice. The first time, we skip objects which may
1100 introduce version mismatches. The second time, we force
1101 their use. See ldelf_vercheck comment. */
1102 for (force
= 0; force
< 2; force
++)
1105 search_dirs_type
*search
;
1107 struct bfd_link_needed_list
*rp
;
1110 if (ldelf_search_needed (command_line
.rpath_link
, &n
, force
,
1116 path
= command_line
.rpath
;
1119 path
= ldelf_add_sysroot (path
);
1120 found
= ldelf_search_needed (path
, &n
, force
,
1122 free ((char *) path
);
1129 if (command_line
.rpath_link
== NULL
1130 && command_line
.rpath
== NULL
)
1132 path
= (const char *) getenv ("LD_RUN_PATH");
1134 && ldelf_search_needed (path
, &n
, force
,
1138 path
= (const char *) getenv ("LD_LIBRARY_PATH");
1140 && ldelf_search_needed (path
, &n
, force
,
1147 rp
= bfd_elf_get_runpath_list (link_info
.output_bfd
, &link_info
);
1148 for (; !found
&& rp
!= NULL
; rp
= rp
->next
)
1150 path
= ldelf_add_sysroot (rp
->name
);
1151 found
= (rp
->by
== l
->by
1152 && ldelf_search_needed (path
, &n
, force
,
1153 is_linux
, elfsize
));
1154 free ((char *) path
);
1160 && ldelf_check_ld_elf_hints (l
, force
, elfsize
))
1164 && ldelf_check_ld_so_conf (l
, force
, elfsize
, prefix
))
1168 len
= strlen (l
->name
);
1169 for (search
= search_head
; search
!= NULL
; search
= search
->next
)
1173 if (search
->cmdline
)
1175 filename
= (char *) xmalloc (strlen (search
->name
) + len
+ 2);
1176 sprintf (filename
, "%s/%s", search
->name
, l
->name
);
1178 if (ldelf_try_needed (&nn
, force
, is_linux
))
1189 einfo (_("%P: warning: %s, needed by %pB, not found "
1190 "(try using -rpath or -rpath-link)\n"),
1194 /* Don't add DT_NEEDED when loading shared objects from DT_NEEDED for
1195 plugin symbol resolution while handling DT_NEEDED entries. */
1196 if (!htab
->handling_dt_needed
)
1197 for (abfd
= link_info
.input_bfds
; abfd
; abfd
= abfd
->link
.next
)
1198 if (bfd_get_format (abfd
) == bfd_object
1199 && ((abfd
->flags
) & DYNAMIC
) != 0
1200 && bfd_get_flavour (abfd
) == bfd_target_elf_flavour
1201 && (elf_dyn_lib_class (abfd
) & (DYN_AS_NEEDED
| DYN_NO_NEEDED
)) == 0
1202 && elf_dt_name (abfd
) != NULL
)
1204 if (bfd_elf_add_dt_needed_tag (abfd
, &link_info
) < 0)
1205 einfo (_("%F%P: failed to add DT_NEEDED dynamic tag\n"));
1208 link_info
.input_bfds_tail
= save_input_bfd_tail
;
1209 *save_input_bfd_tail
= NULL
;
1212 /* This is called before calling plugin 'all symbols read' hook. */
1215 ldelf_before_plugin_all_symbols_read (int use_libpath
, int native
,
1216 int is_linux
, int is_freebsd
,
1217 int elfsize
, const char *prefix
)
1219 struct elf_link_hash_table
*htab
= elf_hash_table (&link_info
);
1221 if (!link_info
.lto_plugin_active
1222 || !is_elf_hash_table (&htab
->root
))
1225 htab
->handling_dt_needed
= true;
1226 ldelf_handle_dt_needed (htab
, use_libpath
, native
, is_linux
,
1227 is_freebsd
, elfsize
, prefix
);
1228 htab
->handling_dt_needed
= false;
1231 /* This is called after all the input files have been opened and all
1232 symbols have been loaded. */
1235 ldelf_after_open (int use_libpath
, int native
, int is_linux
, int is_freebsd
,
1236 int elfsize
, const char *prefix
)
1238 struct elf_link_hash_table
*htab
;
1242 after_open_default ();
1244 htab
= elf_hash_table (&link_info
);
1245 if (!is_elf_hash_table (&htab
->root
))
1248 if (command_line
.out_implib_filename
)
1250 unlink_if_ordinary (command_line
.out_implib_filename
);
1251 link_info
.out_implib_bfd
1252 = bfd_openw (command_line
.out_implib_filename
,
1253 bfd_get_target (link_info
.output_bfd
));
1255 if (link_info
.out_implib_bfd
== NULL
)
1257 einfo (_("%F%P: %s: can't open for writing: %E\n"),
1258 command_line
.out_implib_filename
);
1262 if (ldelf_emit_note_gnu_build_id
!= NULL
1263 || ldelf_emit_note_fdo_package_metadata
!= NULL
)
1265 /* Find an ELF input. */
1266 for (abfd
= link_info
.input_bfds
;
1267 abfd
!= (bfd
*) NULL
; abfd
= abfd
->link
.next
)
1268 if (bfd_get_flavour (abfd
) == bfd_target_elf_flavour
1269 && bfd_count_sections (abfd
) != 0
1270 && !bfd_input_just_syms (abfd
))
1273 /* PR 10555: If there are no ELF input files do not try to
1274 create a .note.gnu-build-id section. */
1276 || (ldelf_emit_note_gnu_build_id
!= NULL
1277 && !ldelf_setup_build_id (abfd
)))
1279 free ((char *) ldelf_emit_note_gnu_build_id
);
1280 ldelf_emit_note_gnu_build_id
= NULL
;
1284 || (ldelf_emit_note_fdo_package_metadata
!= NULL
1285 && !ldelf_setup_package_metadata (abfd
)))
1287 free ((char *) ldelf_emit_note_fdo_package_metadata
);
1288 ldelf_emit_note_fdo_package_metadata
= NULL
;
1292 get_elf_backend_data (link_info
.output_bfd
)->setup_gnu_properties (&link_info
);
1294 /* Do not allow executable files to be used as inputs to the link. */
1295 for (abfd
= link_info
.input_bfds
; abfd
; abfd
= abfd
->link
.next
)
1297 /* Discard input .note.gnu.build-id sections. */
1298 s
= bfd_get_section_by_name (abfd
, ".note.gnu.build-id");
1301 if (s
!= elf_tdata (link_info
.output_bfd
)->o
->build_id
.sec
)
1302 s
->flags
|= SEC_EXCLUDE
;
1303 s
= bfd_get_next_section_by_name (NULL
, s
);
1306 if (abfd
->xvec
->flavour
== bfd_target_elf_flavour
1307 && !bfd_input_just_syms (abfd
)
1308 && elf_tdata (abfd
) != NULL
1309 /* FIXME: Maybe check for other non-supportable types as well ? */
1310 && (elf_tdata (abfd
)->elf_header
->e_type
== ET_EXEC
1311 || (elf_tdata (abfd
)->elf_header
->e_type
== ET_DYN
1312 && elf_tdata (abfd
)->is_pie
)))
1313 einfo (_("%F%P: cannot use executable file '%pB' as input to a link\n"),
1317 if (bfd_link_relocatable (&link_info
))
1319 if (link_info
.execstack
== !link_info
.noexecstack
)
1321 /* PR ld/16744: If "-z [no]execstack" has been specified on the
1322 command line and we are perfoming a relocatable link then no
1323 PT_GNU_STACK segment will be created and so the
1324 linkinfo.[no]execstack values set in _handle_option() will have no
1325 effect. Instead we create a .note.GNU-stack section in much the
1326 same way as the assembler does with its --[no]execstack option. */
1327 flagword flags
= SEC_READONLY
| (link_info
.execstack
? SEC_CODE
: 0);
1328 (void) bfd_make_section_with_flags (link_info
.input_bfds
,
1329 ".note.GNU-stack", flags
);
1334 if (!link_info
.traditional_format
)
1337 bool warn_eh_frame
= false;
1340 for (abfd
= link_info
.input_bfds
; abfd
; abfd
= abfd
->link
.next
)
1344 if (bfd_input_just_syms (abfd
))
1347 for (s
= abfd
->sections
; s
&& type
< COMPACT_EH_HDR
; s
= s
->next
)
1349 const char *name
= bfd_section_name (s
);
1351 if (bfd_is_abs_section (s
->output_section
))
1353 if (startswith (name
, ".eh_frame_entry"))
1354 type
= COMPACT_EH_HDR
;
1355 else if (strcmp (name
, ".eh_frame") == 0 && s
->size
> 8)
1356 type
= DWARF2_EH_HDR
;
1365 else if (seen_type
!= type
)
1367 einfo (_("%F%P: compact frame descriptions incompatible with"
1368 " DWARF2 .eh_frame from %pB\n"),
1369 type
== DWARF2_EH_HDR
? abfd
: elfbfd
);
1374 && (type
== COMPACT_EH_HDR
1375 || link_info
.eh_frame_hdr_type
!= 0))
1377 if (bfd_get_flavour (abfd
) == bfd_target_elf_flavour
)
1380 warn_eh_frame
= true;
1384 if (seen_type
== COMPACT_EH_HDR
)
1385 link_info
.eh_frame_hdr_type
= COMPACT_EH_HDR
;
1389 const struct elf_backend_data
*bed
;
1391 bed
= get_elf_backend_data (elfbfd
);
1392 s
= bfd_make_section_with_flags (elfbfd
, ".eh_frame_hdr",
1393 bed
->dynamic_sec_flags
1396 && bfd_set_section_alignment (s
, 2))
1398 htab
->eh_info
.hdr_sec
= s
;
1399 warn_eh_frame
= false;
1403 einfo (_("%P: warning: cannot create .eh_frame_hdr section,"
1404 " --eh-frame-hdr ignored\n"));
1407 if (link_info
.eh_frame_hdr_type
== COMPACT_EH_HDR
)
1408 if (!bfd_elf_parse_eh_frame_entries (NULL
, &link_info
))
1409 einfo (_("%F%P: failed to parse EH frame entries\n"));
1411 ldelf_handle_dt_needed (htab
, use_libpath
, native
, is_linux
,
1412 is_freebsd
, elfsize
, prefix
);
1415 static bfd_size_type
1416 id_note_section_size (bfd
*abfd ATTRIBUTE_UNUSED
)
1418 const char *style
= ldelf_emit_note_gnu_build_id
;
1420 bfd_size_type build_id_size
;
1422 size
= offsetof (Elf_External_Note
, name
[sizeof "GNU"]);
1423 size
= (size
+ 3) & -(bfd_size_type
) 4;
1425 build_id_size
= compute_build_id_size (style
);
1427 size
+= build_id_size
;
1435 write_build_id (bfd
*abfd
)
1437 const struct elf_backend_data
*bed
= get_elf_backend_data (abfd
);
1438 struct elf_obj_tdata
*t
= elf_tdata (abfd
);
1441 Elf_Internal_Shdr
*i_shdr
;
1442 unsigned char *contents
, *id_bits
;
1445 Elf_External_Note
*e_note
;
1447 style
= t
->o
->build_id
.style
;
1448 asec
= t
->o
->build_id
.sec
;
1449 if (bfd_is_abs_section (asec
->output_section
))
1451 einfo (_("%P: warning: .note.gnu.build-id section discarded,"
1452 " --build-id ignored\n"));
1455 i_shdr
= &elf_section_data (asec
->output_section
)->this_hdr
;
1457 if (i_shdr
->contents
== NULL
)
1459 if (asec
->contents
== NULL
)
1460 asec
->contents
= (unsigned char *) xmalloc (asec
->size
);
1461 contents
= asec
->contents
;
1464 contents
= i_shdr
->contents
+ asec
->output_offset
;
1466 e_note
= (Elf_External_Note
*) contents
;
1467 size
= offsetof (Elf_External_Note
, name
[sizeof "GNU"]);
1468 size
= (size
+ 3) & -(bfd_size_type
) 4;
1469 id_bits
= contents
+ size
;
1470 size
= asec
->size
- size
;
1472 /* Clear the build ID field. */
1473 memset (id_bits
, 0, size
);
1475 bfd_h_put_32 (abfd
, sizeof "GNU", &e_note
->namesz
);
1476 bfd_h_put_32 (abfd
, size
, &e_note
->descsz
);
1477 bfd_h_put_32 (abfd
, NT_GNU_BUILD_ID
, &e_note
->type
);
1478 memcpy (e_note
->name
, "GNU", sizeof "GNU");
1480 generate_build_id (abfd
, style
, bed
->s
->checksum_contents
, id_bits
, size
);
1482 position
= i_shdr
->sh_offset
+ asec
->output_offset
;
1484 return (bfd_seek (abfd
, position
, SEEK_SET
) == 0
1485 && bfd_write (contents
, size
, abfd
) == size
);
1488 /* Make .note.gnu.build-id section, and set up elf_tdata->build_id. */
1491 ldelf_setup_build_id (bfd
*ibfd
)
1497 size
= id_note_section_size (ibfd
);
1500 einfo (_("%P: warning: unrecognized --build-id style ignored\n"));
1504 flags
= (SEC_ALLOC
| SEC_LOAD
| SEC_IN_MEMORY
1505 | SEC_LINKER_CREATED
| SEC_READONLY
| SEC_DATA
);
1506 s
= bfd_make_section_anyway_with_flags (ibfd
, ".note.gnu.build-id",
1508 if (s
!= NULL
&& bfd_set_section_alignment (s
, 2))
1510 struct elf_obj_tdata
*t
= elf_tdata (link_info
.output_bfd
);
1511 t
->o
->build_id
.after_write_object_contents
= &write_build_id
;
1512 t
->o
->build_id
.style
= ldelf_emit_note_gnu_build_id
;
1513 t
->o
->build_id
.sec
= s
;
1514 elf_section_type (s
) = SHT_NOTE
;
1519 einfo (_("%P: warning: cannot create .note.gnu.build-id section,"
1520 " --build-id ignored\n"));
1525 write_package_metadata (bfd
*abfd
)
1527 struct elf_obj_tdata
*t
= elf_tdata (abfd
);
1530 Elf_Internal_Shdr
*i_shdr
;
1531 unsigned char *contents
, *json_bits
;
1534 Elf_External_Note
*e_note
;
1536 json
= t
->o
->package_metadata
.json
;
1537 asec
= t
->o
->package_metadata
.sec
;
1538 if (bfd_is_abs_section (asec
->output_section
))
1540 einfo (_("%P: warning: .note.package section discarded,"
1541 " --package-metadata ignored\n"));
1544 i_shdr
= &elf_section_data (asec
->output_section
)->this_hdr
;
1546 if (i_shdr
->contents
== NULL
)
1548 if (asec
->contents
== NULL
)
1549 asec
->contents
= (unsigned char *) xmalloc (asec
->size
);
1550 contents
= asec
->contents
;
1553 contents
= i_shdr
->contents
+ asec
->output_offset
;
1555 e_note
= (Elf_External_Note
*) contents
;
1556 size
= offsetof (Elf_External_Note
, name
[sizeof "FDO"]);
1557 size
= (size
+ 3) & -(bfd_size_type
) 4;
1558 json_bits
= contents
+ size
;
1559 size
= asec
->size
- size
;
1561 /* Clear the package metadata field. */
1562 memset (json_bits
, 0, size
);
1564 bfd_h_put_32 (abfd
, sizeof "FDO", &e_note
->namesz
);
1565 bfd_h_put_32 (abfd
, size
, &e_note
->descsz
);
1566 bfd_h_put_32 (abfd
, FDO_PACKAGING_METADATA
, &e_note
->type
);
1567 memcpy (e_note
->name
, "FDO", sizeof "FDO");
1568 memcpy (json_bits
, json
, strlen(json
));
1570 position
= i_shdr
->sh_offset
+ asec
->output_offset
;
1572 return (bfd_seek (abfd
, position
, SEEK_SET
) == 0
1573 && bfd_write (contents
, size
, abfd
) == size
);
1576 /* Make .note.package section.
1577 https://systemd.io/ELF_PACKAGE_METADATA/ */
1580 ldelf_setup_package_metadata (bfd
*ibfd
)
1587 /* If the option wasn't specified, silently return. */
1588 if (!ldelf_emit_note_fdo_package_metadata
)
1591 /* The option was specified, but it's empty, log and return. */
1592 json_length
= strlen (ldelf_emit_note_fdo_package_metadata
);
1593 if (json_length
== 0)
1595 einfo (_("%P: warning: --package-metadata is empty, ignoring\n"));
1600 json_error_t json_error
;
1601 json_t
*json
= json_loads (ldelf_emit_note_fdo_package_metadata
,
1605 einfo (_("%P: warning: --package-metadata=%s does not contain valid "
1606 "JSON, ignoring: %s\n"),
1607 ldelf_emit_note_fdo_package_metadata
, json_error
.text
);
1614 size
= offsetof (Elf_External_Note
, name
[sizeof "FDO"]);
1615 size
+= json_length
+ 1;
1616 size
= (size
+ 3) & -(bfd_size_type
) 4;
1618 flags
= (SEC_ALLOC
| SEC_LOAD
| SEC_IN_MEMORY
1619 | SEC_LINKER_CREATED
| SEC_READONLY
| SEC_DATA
);
1620 s
= bfd_make_section_anyway_with_flags (ibfd
, ".note.package",
1622 if (s
!= NULL
&& bfd_set_section_alignment (s
, 2))
1624 struct elf_obj_tdata
*t
= elf_tdata (link_info
.output_bfd
);
1625 t
->o
->package_metadata
.after_write_object_contents
1626 = &write_package_metadata
;
1627 t
->o
->package_metadata
.json
= ldelf_emit_note_fdo_package_metadata
;
1628 t
->o
->package_metadata
.sec
= s
;
1629 elf_section_type (s
) = SHT_NOTE
;
1634 einfo (_("%P: warning: cannot create .note.package section,"
1635 " --package-metadata ignored\n"));
1639 /* Look through an expression for an assignment statement. */
1642 ldelf_find_exp_assignment (etree_type
*exp
)
1644 bool provide
= false;
1646 switch (exp
->type
.node_class
)
1649 case etree_provided
:
1653 /* We call record_link_assignment even if the symbol is defined.
1654 This is because if it is defined by a dynamic object, we
1655 actually want to use the value defined by the linker script,
1656 not the value from the dynamic object (because we are setting
1657 symbols like etext). If the symbol is defined by a regular
1658 object, then, as it happens, calling record_link_assignment
1660 if (strcmp (exp
->assign
.dst
, ".") != 0)
1662 if (!bfd_elf_record_link_assignment (link_info
.output_bfd
,
1664 exp
->assign
.dst
, provide
,
1665 exp
->assign
.hidden
))
1666 einfo (_("%F%P: failed to record assignment to %s: %E\n"),
1669 ldelf_find_exp_assignment (exp
->assign
.src
);
1673 ldelf_find_exp_assignment (exp
->binary
.lhs
);
1674 ldelf_find_exp_assignment (exp
->binary
.rhs
);
1678 ldelf_find_exp_assignment (exp
->trinary
.cond
);
1679 ldelf_find_exp_assignment (exp
->trinary
.lhs
);
1680 ldelf_find_exp_assignment (exp
->trinary
.rhs
);
1684 ldelf_find_exp_assignment (exp
->unary
.child
);
1692 /* This is called by the before_allocation routine via
1693 lang_for_each_statement. It locates any assignment statements, and
1694 tells the ELF backend about them, in case they are assignments to
1695 symbols which are referred to by dynamic objects. */
1698 ldelf_find_statement_assignment (lang_statement_union_type
*s
)
1700 if (s
->header
.type
== lang_assignment_statement_enum
)
1701 ldelf_find_exp_assignment (s
->assignment_statement
.exp
);
1704 /* Used by before_allocation and handle_option. */
1707 ldelf_append_to_separated_string (char **to
, char *op_arg
)
1710 *to
= xstrdup (op_arg
);
1713 size_t to_len
= strlen (*to
);
1714 size_t op_arg_len
= strlen (op_arg
);
1718 /* First see whether OPTARG is already in the path. */
1721 if (strncmp (op_arg
, cp
, op_arg_len
) == 0
1722 && (cp
[op_arg_len
] == 0
1723 || cp
[op_arg_len
] == config
.rpath_separator
))
1727 /* Not yet found. */
1728 cp
= strchr (cp
, config
.rpath_separator
);
1736 buf
= xmalloc (to_len
+ op_arg_len
+ 2);
1737 sprintf (buf
, "%s%c%s", *to
,
1738 config
.rpath_separator
, op_arg
);
1745 /* This is called after the sections have been attached to output
1746 sections, but before any sizes or addresses have been set. */
1749 ldelf_before_allocation (char *audit
, char *depaudit
,
1750 const char *default_interpreter_name
)
1755 struct bfd_link_hash_entry
*ehdr_start
= NULL
;
1756 unsigned char ehdr_start_save_type
= 0;
1757 char ehdr_start_save_u
[sizeof ehdr_start
->u
1758 - sizeof ehdr_start
->u
.def
.next
] = "";
1760 if (is_elf_hash_table (link_info
.hash
))
1762 _bfd_elf_tls_setup (link_info
.output_bfd
, &link_info
);
1764 /* Make __ehdr_start hidden if it has been referenced, to
1765 prevent the symbol from being dynamic. */
1766 if (!bfd_link_relocatable (&link_info
))
1768 struct elf_link_hash_table
*htab
= elf_hash_table (&link_info
);
1769 struct elf_link_hash_entry
*h
1770 = elf_link_hash_lookup (htab
, "__ehdr_start", false, false, true);
1772 /* Only adjust the export class if the symbol was referenced
1773 and not defined, otherwise leave it alone. */
1775 && (h
->root
.type
== bfd_link_hash_new
1776 || h
->root
.type
== bfd_link_hash_undefined
1777 || h
->root
.type
== bfd_link_hash_undefweak
1778 || h
->root
.type
== bfd_link_hash_common
))
1780 /* Don't leave the symbol undefined. Undefined hidden
1781 symbols typically won't have dynamic relocations, but
1782 we most likely will need dynamic relocations for
1783 __ehdr_start if we are building a PIE or shared
1785 ehdr_start
= &h
->root
;
1786 ehdr_start_save_type
= ehdr_start
->type
;
1787 memcpy (ehdr_start_save_u
,
1788 (char *) &ehdr_start
->u
+ sizeof ehdr_start
->u
.def
.next
,
1789 sizeof ehdr_start_save_u
);
1790 ehdr_start
->type
= bfd_link_hash_defined
;
1791 /* It will be converted to section-relative later. */
1792 ehdr_start
->u
.def
.section
= bfd_abs_section_ptr
;
1793 ehdr_start
->u
.def
.value
= 0;
1797 /* If we are going to make any variable assignments, we need to
1798 let the ELF backend know about them in case the variables are
1799 referred to by dynamic objects. */
1800 lang_for_each_statement (ldelf_find_statement_assignment
);
1803 /* Let the ELF backend work out the sizes of any sections required
1804 by dynamic linking. */
1805 rpath
= command_line
.rpath
;
1807 rpath
= (const char *) getenv ("LD_RUN_PATH");
1809 for (abfd
= link_info
.input_bfds
; abfd
; abfd
= abfd
->link
.next
)
1810 if (bfd_get_flavour (abfd
) == bfd_target_elf_flavour
)
1812 const char *audit_libs
= elf_dt_audit (abfd
);
1814 /* If the input bfd contains an audit entry, we need to add it as
1815 a dep audit entry. */
1816 if (audit_libs
&& *audit_libs
!= '\0')
1818 char *cp
= xstrdup (audit_libs
);
1822 char *cp2
= strchr (cp
, config
.rpath_separator
);
1830 if (cp
!= NULL
&& *cp
!= '\0')
1831 ldelf_append_to_separated_string (&depaudit
, cp
);
1833 cp
= more
? ++cp2
: NULL
;
1839 if (! (bfd_elf_size_dynamic_sections
1840 (link_info
.output_bfd
, command_line
.soname
, rpath
,
1841 command_line
.filter_shlib
, audit
, depaudit
,
1842 (const char * const *) command_line
.auxiliary_filters
,
1843 &link_info
, &sinterp
)))
1844 einfo (_("%F%P: failed to set dynamic section sizes: %E\n"));
1846 if (sinterp
!= NULL
)
1848 /* Let the user override the dynamic linker we are using. */
1849 if (command_line
.interpreter
!= NULL
)
1850 default_interpreter_name
= command_line
.interpreter
;
1851 if (default_interpreter_name
!= NULL
)
1853 sinterp
->contents
= (bfd_byte
*) default_interpreter_name
;
1854 sinterp
->size
= strlen ((char *) sinterp
->contents
) + 1;
1858 /* Look for any sections named .gnu.warning. As a GNU extensions,
1859 we treat such sections as containing warning messages. We print
1860 out the warning message, and then zero out the section size so
1861 that it does not get copied into the output file. */
1864 LANG_FOR_EACH_INPUT_STATEMENT (is
)
1870 if (is
->flags
.just_syms
)
1873 s
= bfd_get_section_by_name (is
->the_bfd
, ".gnu.warning");
1878 msg
= (char *) xmalloc ((size_t) (sz
+ 1));
1879 if (! bfd_get_section_contents (is
->the_bfd
, s
, msg
,
1881 einfo (_("%F%P: %pB: can't read contents of section .gnu.warning: %E\n"),
1884 (*link_info
.callbacks
->warning
) (&link_info
, msg
,
1885 (const char *) NULL
, is
->the_bfd
,
1886 (asection
*) NULL
, (bfd_vma
) 0);
1889 /* Clobber the section size, so that we don't waste space
1890 copying the warning into the output file. If we've already
1891 sized the output section, adjust its size. The adjustment
1892 is on rawsize because targets that size sections early will
1893 have called lang_reset_memory_regions after sizing. */
1894 if (s
->output_section
!= NULL
1895 && s
->output_section
->rawsize
>= s
->size
)
1896 s
->output_section
->rawsize
-= s
->size
;
1900 /* Also set SEC_EXCLUDE, so that local symbols defined in the
1901 warning section don't get copied to the output. */
1902 s
->flags
|= SEC_EXCLUDE
| SEC_KEEP
;
1906 before_allocation_default ();
1908 if (!bfd_elf_size_dynsym_hash_dynstr (link_info
.output_bfd
, &link_info
))
1909 einfo (_("%F%P: failed to set dynamic section sizes: %E\n"));
1911 if (ehdr_start
!= NULL
)
1913 /* If we twiddled __ehdr_start to defined earlier, put it back
1915 ehdr_start
->type
= ehdr_start_save_type
;
1916 memcpy ((char *) &ehdr_start
->u
+ sizeof ehdr_start
->u
.def
.next
,
1918 sizeof ehdr_start_save_u
);
1921 /* Try to open a dynamic archive. This is where we know that ELF
1922 dynamic libraries have an extension of .so (or .sl on oddball systems
1926 ldelf_open_dynamic_archive (const char *arch
, search_dirs_type
*search
,
1927 lang_input_statement_type
*entry
)
1929 const char *filename
;
1932 bool opened
= false;
1934 if (! entry
->flags
.maybe_archive
)
1937 filename
= entry
->filename
;
1938 len
= strlen (search
->name
) + strlen (filename
);
1939 if (entry
->flags
.full_name_provided
)
1942 string
= (char *) xmalloc (len
);
1943 sprintf (string
, "%s/%s", search
->name
, filename
);
1949 len
+= strlen (arch
) + sizeof "/lib.so";
1950 #ifdef EXTRA_SHLIB_EXTENSION
1951 xlen
= (strlen (EXTRA_SHLIB_EXTENSION
) > 3
1952 ? strlen (EXTRA_SHLIB_EXTENSION
) - 3
1955 string
= (char *) xmalloc (len
+ xlen
);
1956 sprintf (string
, "%s/lib%s%s.so", search
->name
, filename
, arch
);
1957 #ifdef EXTRA_SHLIB_EXTENSION
1958 /* Try the .so extension first. If that fails build a new filename
1959 using EXTRA_SHLIB_EXTENSION. */
1960 opened
= ldfile_try_open_bfd (string
, entry
);
1962 strcpy (string
+ len
- 4, EXTRA_SHLIB_EXTENSION
);
1966 if (!opened
&& !ldfile_try_open_bfd (string
, entry
))
1972 entry
->filename
= string
;
1974 /* We have found a dynamic object to include in the link. The ELF
1975 backend linker will create a DT_NEEDED entry in the .dynamic
1976 section naming this file. If this file includes a DT_SONAME
1977 entry, it will be used. Otherwise, the ELF linker will just use
1978 the name of the file. For an archive found by searching, like
1979 this one, the DT_NEEDED entry should consist of just the name of
1980 the file, without the path information used to find it. Note
1981 that we only need to do this if we have a dynamic object; an
1982 archive will never be referenced by a DT_NEEDED entry.
1984 FIXME: This approach--using bfd_elf_set_dt_needed_name--is not
1985 very pretty. I haven't been able to think of anything that is
1987 if (bfd_check_format (entry
->the_bfd
, bfd_object
)
1988 && (entry
->the_bfd
->flags
& DYNAMIC
) != 0)
1990 ASSERT (entry
->flags
.maybe_archive
&& entry
->flags
.search_dirs
);
1992 /* Rather than duplicating the logic above. Just use the
1993 filename we recorded earlier. */
1995 if (!entry
->flags
.full_name_provided
)
1996 filename
= lbasename (entry
->filename
);
1997 bfd_elf_set_dt_needed_name (entry
->the_bfd
, filename
);
2003 /* A variant of lang_output_section_find used by place_orphan. */
2005 static lang_output_section_statement_type
*
2006 output_rel_find (int isdyn
, int rela
)
2008 lang_output_section_statement_type
*lookup
;
2009 lang_output_section_statement_type
*last
= NULL
;
2010 lang_output_section_statement_type
*last_alloc
= NULL
;
2011 lang_output_section_statement_type
*last_ro_alloc
= NULL
;
2012 lang_output_section_statement_type
*last_rel
= NULL
;
2013 lang_output_section_statement_type
*last_rel_alloc
= NULL
;
2015 for (lookup
= (void *) lang_os_list
.head
;
2017 lookup
= lookup
->next
)
2019 if (lookup
->constraint
>= 0
2020 && startswith (lookup
->name
, ".rel"))
2022 int lookrela
= lookup
->name
[4] == 'a';
2024 /* .rel.dyn must come before all other reloc sections, to suit
2029 /* Don't place after .rel.plt as doing so results in wrong
2031 if (strcmp (".plt", lookup
->name
+ 4 + lookrela
) == 0)
2034 if (rela
== lookrela
|| last_rel
== NULL
)
2036 if ((rela
== lookrela
|| last_rel_alloc
== NULL
)
2037 && lookup
->bfd_section
!= NULL
2038 && (lookup
->bfd_section
->flags
& SEC_ALLOC
) != 0)
2039 last_rel_alloc
= lookup
;
2043 if (lookup
->bfd_section
!= NULL
2044 && (lookup
->bfd_section
->flags
& SEC_ALLOC
) != 0)
2046 last_alloc
= lookup
;
2047 if ((lookup
->bfd_section
->flags
& SEC_READONLY
) != 0)
2048 last_ro_alloc
= lookup
;
2053 return last_rel_alloc
;
2059 return last_ro_alloc
;
2067 /* Return whether IN is suitable to be part of OUT. */
2070 elf_orphan_compatible (asection
*in
, asection
*out
)
2072 /* Non-zero sh_info implies a section with SHF_INFO_LINK with
2073 unknown semantics for the generic linker, or a SHT_REL/SHT_RELA
2074 section where sh_info specifies a symbol table. (We won't see
2075 SHT_GROUP, SHT_SYMTAB or SHT_DYNSYM sections here.) We clearly
2076 can't merge SHT_REL/SHT_RELA using differing symbol tables, and
2077 shouldn't merge sections with differing unknown semantics. */
2078 if (elf_section_data (out
)->this_hdr
.sh_info
2079 != elf_section_data (in
)->this_hdr
.sh_info
)
2081 /* We can't merge with a member of an output section group or merge
2082 two sections with differing SHF_EXCLUDE or other processor and OS
2083 specific flags or with different SHF_LINK_ORDER when doing a
2084 relocatable link. */
2085 if (bfd_link_relocatable (&link_info
)
2086 && (elf_next_in_group (out
) != NULL
2087 || ((elf_section_flags (in
) & SHF_LINK_ORDER
) != 0
2088 && (elf_section_flags (out
) & SHF_LINK_ORDER
) != 0
2089 && (elf_linked_to_section (in
)->output_section
2090 != elf_linked_to_section (out
)->output_section
))
2091 || ((elf_section_flags (out
) ^ elf_section_flags (in
))
2092 & (SHF_MASKPROC
| SHF_MASKOS
)) != 0))
2094 return _bfd_elf_match_sections_by_type (link_info
.output_bfd
, out
,
2098 /* Place an orphan section. We use this to put random SHF_ALLOC
2099 sections in the right segment. */
2101 lang_output_section_statement_type
*
2102 ldelf_place_orphan (asection
*s
, const char *secname
, int constraint
)
2104 static struct orphan_save hold
[] =
2107 SEC_HAS_CONTENTS
| SEC_ALLOC
| SEC_LOAD
| SEC_READONLY
| SEC_CODE
,
2110 SEC_HAS_CONTENTS
| SEC_ALLOC
| SEC_LOAD
| SEC_READONLY
| SEC_DATA
,
2113 SEC_HAS_CONTENTS
| SEC_ALLOC
| SEC_LOAD
| SEC_DATA
| SEC_THREAD_LOCAL
,
2116 SEC_HAS_CONTENTS
| SEC_ALLOC
| SEC_LOAD
| SEC_DATA
,
2122 SEC_HAS_CONTENTS
| SEC_ALLOC
| SEC_LOAD
| SEC_READONLY
| SEC_DATA
,
2125 SEC_HAS_CONTENTS
| SEC_ALLOC
| SEC_LOAD
| SEC_READONLY
| SEC_DATA
,
2128 SEC_HAS_CONTENTS
| SEC_ALLOC
| SEC_LOAD
| SEC_DATA
| SEC_SMALL_DATA
,
2134 enum orphan_save_index
2146 static int orphan_init_done
= 0;
2147 struct orphan_save
*place
;
2148 lang_output_section_statement_type
*after
;
2149 lang_output_section_statement_type
*os
;
2150 lang_output_section_statement_type
*match_by_name
= NULL
;
2152 int elfinput
= s
->owner
->xvec
->flavour
== bfd_target_elf_flavour
;
2153 int elfoutput
= link_info
.output_bfd
->xvec
->flavour
== bfd_target_elf_flavour
;
2154 unsigned int sh_type
= elfinput
? elf_section_type (s
) : SHT_NULL
;
2158 if (!bfd_link_relocatable (&link_info
)
2159 && link_info
.combreloc
2160 && (s
->flags
& SEC_ALLOC
))
2166 secname
= ".rela.dyn";
2170 secname
= ".rel.dyn";
2176 else if (startswith (secname
, ".rel"))
2178 secname
= secname
[4] == 'a' ? ".rela.dyn" : ".rel.dyn";
2183 if (!bfd_link_relocatable (&link_info
)
2186 && (s
->flags
& SEC_ALLOC
) != 0
2187 && (elf_tdata (s
->owner
)->has_gnu_osabi
& elf_gnu_osabi_mbind
) != 0
2188 && (elf_section_flags (s
) & SHF_GNU_MBIND
) != 0)
2190 /* Find the output mbind section with the same type, attributes
2191 and sh_info field. */
2192 for (os
= (void *) lang_os_list
.head
;
2195 if (os
->bfd_section
!= NULL
2196 && !bfd_is_abs_section (os
->bfd_section
)
2197 && (elf_section_flags (os
->bfd_section
) & SHF_GNU_MBIND
) != 0
2198 && ((s
->flags
& (SEC_ALLOC
2203 == (os
->bfd_section
->flags
& (SEC_ALLOC
2208 && (elf_section_data (os
->bfd_section
)->this_hdr
.sh_info
2209 == elf_section_data (s
)->this_hdr
.sh_info
))
2211 lang_add_section (&os
->children
, s
, NULL
, NULL
, os
);
2215 /* Create the output mbind section with the ".mbind." prefix
2217 if ((s
->flags
& (SEC_LOAD
| SEC_HAS_CONTENTS
)) == 0)
2218 secname
= ".mbind.bss";
2219 else if ((s
->flags
& SEC_READONLY
) == 0)
2220 secname
= ".mbind.data";
2221 else if ((s
->flags
& SEC_CODE
) == 0)
2222 secname
= ".mbind.rodata";
2224 secname
= ".mbind.text";
2225 elf_tdata (link_info
.output_bfd
)->has_gnu_osabi
|= elf_gnu_osabi_mbind
;
2228 /* Look through the script to see where to place this section. The
2229 script includes entries added by previous lang_insert_orphan
2230 calls, so this loop puts multiple compatible orphans of the same
2231 name into a single output section. */
2232 if (constraint
== 0)
2233 for (os
= lang_output_section_find (secname
);
2235 os
= next_matching_output_section_statement (os
, 0))
2237 /* If we don't match an existing output section, tell
2238 lang_insert_orphan to create a new output section. */
2239 constraint
= SPECIAL
;
2241 /* Check to see if we already have an output section statement
2242 with this name, and its bfd section has compatible flags.
2243 If the section already exists but does not have any flags
2244 set, then it has been created by the linker, possibly as a
2245 result of a --section-start command line switch. */
2246 if (os
->bfd_section
!= NULL
2247 && !bfd_is_abs_section (os
->bfd_section
)
2248 && (os
->bfd_section
->flags
== 0
2249 || (((s
->flags
^ os
->bfd_section
->flags
)
2250 & (SEC_LOAD
| SEC_ALLOC
)) == 0
2253 || elf_orphan_compatible (s
, os
->bfd_section
)))))
2255 lang_add_section (&os
->children
, s
, NULL
, NULL
, os
);
2259 /* Save unused output sections in case we can match them
2260 against orphans later. */
2261 if (os
->bfd_section
== NULL
)
2265 /* If we didn't match an active output section, see if we matched an
2266 unused one and use that. */
2269 lang_add_section (&match_by_name
->children
, s
, NULL
, NULL
, match_by_name
);
2270 return match_by_name
;
2273 if (!orphan_init_done
)
2275 struct orphan_save
*ho
;
2277 for (ho
= hold
; ho
< hold
+ sizeof (hold
) / sizeof (hold
[0]); ++ho
)
2278 if (ho
->name
!= NULL
)
2280 ho
->os
= lang_output_section_find (ho
->name
);
2281 if (ho
->os
!= NULL
&& ho
->os
->flags
== 0)
2282 ho
->os
->flags
= ho
->flags
;
2284 orphan_init_done
= 1;
2287 /* If this is a final link, then always put .gnu.warning.SYMBOL
2288 sections into the .text section to get them out of the way. */
2289 if (bfd_link_executable (&link_info
)
2290 && startswith (s
->name
, ".gnu.warning.")
2291 && hold
[orphan_text
].os
!= NULL
)
2293 os
= hold
[orphan_text
].os
;
2294 lang_add_section (&os
->children
, s
, NULL
, NULL
, os
);
2299 if (!bfd_link_relocatable (&link_info
))
2302 while ((nexts
= bfd_get_next_section_by_name (nexts
->owner
, nexts
))
2304 if (nexts
->output_section
== NULL
2305 && (nexts
->flags
& SEC_EXCLUDE
) == 0
2306 && ((nexts
->flags
^ flags
) & (SEC_LOAD
| SEC_ALLOC
)) == 0
2307 && (nexts
->owner
->flags
& DYNAMIC
) == 0
2308 && !bfd_input_just_syms (nexts
->owner
)
2309 && _bfd_elf_match_sections_by_type (nexts
->owner
, nexts
,
2311 flags
= (((flags
^ SEC_READONLY
)
2312 | (nexts
->flags
^ SEC_READONLY
))
2316 /* Decide which segment the section should go in based on the
2317 section name and section flags. We put loadable .note sections
2318 right after the .interp section, so that the PT_NOTE segment is
2319 stored right after the program headers where the OS can read it
2320 in the first page. */
2323 if ((flags
& (SEC_ALLOC
| SEC_DEBUGGING
)) == 0)
2324 place
= &hold
[orphan_nonalloc
];
2325 else if ((flags
& SEC_ALLOC
) == 0)
2327 else if ((flags
& SEC_LOAD
) != 0
2329 ? sh_type
== SHT_NOTE
2330 : startswith (secname
, ".note")))
2331 place
= &hold
[orphan_interp
];
2332 else if ((flags
& (SEC_LOAD
| SEC_HAS_CONTENTS
| SEC_THREAD_LOCAL
)) == 0)
2333 place
= &hold
[orphan_bss
];
2334 else if ((flags
& SEC_SMALL_DATA
) != 0)
2335 place
= &hold
[orphan_sdata
];
2336 else if ((flags
& SEC_THREAD_LOCAL
) != 0)
2337 place
= &hold
[orphan_tdata
];
2338 else if ((flags
& SEC_READONLY
) == 0)
2339 place
= &hold
[orphan_data
];
2340 else if ((flags
& SEC_LOAD
) != 0
2342 ? sh_type
== SHT_RELA
|| sh_type
== SHT_REL
2343 : startswith (secname
, ".rel")))
2344 place
= &hold
[orphan_rel
];
2345 else if ((flags
& SEC_CODE
) == 0)
2346 place
= &hold
[orphan_rodata
];
2348 place
= &hold
[orphan_text
];
2353 if (place
->os
== NULL
)
2355 if (place
->name
!= NULL
)
2356 place
->os
= lang_output_section_find (place
->name
);
2359 int rela
= elfinput
? sh_type
== SHT_RELA
: secname
[4] == 'a';
2360 place
->os
= output_rel_find (isdyn
, rela
);
2366 = lang_output_section_find_by_flags (s
, flags
, &place
->os
,
2367 _bfd_elf_match_sections_by_type
);
2369 /* *ABS* is always the first output section statement. */
2370 after
= (void *) lang_os_list
.head
;
2373 return lang_insert_orphan (s
, secname
, constraint
, after
, place
, NULL
, NULL
);
2377 ldelf_before_place_orphans (void)
2381 for (abfd
= link_info
.input_bfds
;
2382 abfd
!= (bfd
*) NULL
; abfd
= abfd
->link
.next
)
2383 if (bfd_get_flavour (abfd
) == bfd_target_elf_flavour
2384 && bfd_count_sections (abfd
) != 0
2385 && !bfd_input_just_syms (abfd
))
2388 for (isec
= abfd
->sections
; isec
!= NULL
; isec
= isec
->next
)
2390 /* Discard a section if any of its linked-to section has
2392 asection
*linked_to_sec
;
2393 for (linked_to_sec
= elf_linked_to_section (isec
);
2394 linked_to_sec
!= NULL
&& !linked_to_sec
->linker_mark
;
2395 linked_to_sec
= elf_linked_to_section (linked_to_sec
))
2397 if (discarded_section (linked_to_sec
))
2399 isec
->output_section
= bfd_abs_section_ptr
;
2400 isec
->flags
|= SEC_EXCLUDE
;
2403 linked_to_sec
->linker_mark
= 1;
2405 for (linked_to_sec
= elf_linked_to_section (isec
);
2406 linked_to_sec
!= NULL
&& linked_to_sec
->linker_mark
;
2407 linked_to_sec
= elf_linked_to_section (linked_to_sec
))
2408 linked_to_sec
->linker_mark
= 0;
2414 ldelf_set_output_arch (void)
2416 set_output_arch_default ();
2417 if (link_info
.output_bfd
->xvec
->flavour
== bfd_target_elf_flavour
)
2418 elf_link_info (link_info
.output_bfd
) = &link_info
;