1 /* Copyright (C) 1985-1988, 1990, 1992, 1999-2011
2 Free Software Foundation, Inc.
4 This file is part of GNU Emacs.
6 GNU Emacs 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 GNU Emacs 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 GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */
20 In other words, you are welcome to use, share and improve this program.
21 You are forbidden to forbid anyone else to use, share and improve
22 what you give them. Help stamp out software-hoarding! */
26 * unexec.c - Convert a running program into an a.out file.
28 * Author: Spencer W. Thomas
29 * Computer Science Dept.
31 * Date: Tue Mar 2 1982
32 * Modified heavily since then.
35 * unexec (const char *new_name, const char *old_name);
37 * Takes a snapshot of the program and makes an a.out format file in the
38 * file named by the string argument new_name.
39 * If old_name is non-NULL, the symbol table will be taken from the given file.
40 * On some machines, an existing old_name file is required.
44 /* Even more heavily modified by james@bigtex.cactus.org of Dell Computer Co.
47 * Basic theory: the data space of the running process needs to be
48 * dumped to the output file. Normally we would just enlarge the size
49 * of .data, scooting everything down. But we can't do that in ELF,
50 * because there is often something between the .data space and the
53 * In the temacs dump below, notice that the Global Offset Table
54 * (.got) and the Dynamic link data (.dynamic) come between .data1 and
55 * .bss. It does not work to overlap .data with these fields.
57 * The solution is to create a new .data segment. This segment is
58 * filled with data from the current process. Since the contents of
59 * various sections refer to sections by index, the new .data segment
60 * is made the last in the table to avoid changing any existing index.
62 * This is an example of how the section headers are changed. "Addr"
63 * is a process virtual address. "Offset" is a file offset.
65 raid:/nfs/raid/src/dist-18.56/src> dump -h temacs
69 **** SECTION HEADER TABLE ****
70 [No] Type Flags Addr Offset Size Name
71 Link Info Adralgn Entsize
73 [1] 1 2 0x80480d4 0xd4 0x13 .interp
76 [2] 5 2 0x80480e8 0xe8 0x388 .hash
79 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
82 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
85 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
88 [6] 1 6 0x8049348 0x1348 0x3 .init
91 [7] 1 6 0x804934c 0x134c 0x680 .plt
94 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
97 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
100 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
103 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
106 [12] 1 3 0x8088330 0x3f330 0x20afc .data
109 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
112 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
115 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
118 [16] 8 3 0x80a98f4 0x608f4 0x449c .bss
121 [17] 2 0 0 0x608f4 0x9b90 .symtab
124 [18] 3 0 0 0x6a484 0x8526 .strtab
127 [19] 3 0 0 0x729aa 0x93 .shstrtab
130 [20] 1 0 0 0x72a3d 0x68b7 .comment
133 raid:/nfs/raid/src/dist-18.56/src> dump -h xemacs
137 **** SECTION HEADER TABLE ****
138 [No] Type Flags Addr Offset Size Name
139 Link Info Adralgn Entsize
141 [1] 1 2 0x80480d4 0xd4 0x13 .interp
144 [2] 5 2 0x80480e8 0xe8 0x388 .hash
147 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
150 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
153 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
156 [6] 1 6 0x8049348 0x1348 0x3 .init
159 [7] 1 6 0x804934c 0x134c 0x680 .plt
162 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
165 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
168 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
171 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
174 [12] 1 3 0x8088330 0x3f330 0x20afc .data
177 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
180 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
183 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
186 [16] 8 3 0x80c6800 0x7d800 0 .bss
189 [17] 2 0 0 0x7d800 0x9b90 .symtab
192 [18] 3 0 0 0x87390 0x8526 .strtab
195 [19] 3 0 0 0x8f8b6 0x93 .shstrtab
198 [20] 1 0 0 0x8f949 0x68b7 .comment
201 [21] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
204 * This is an example of how the file header is changed. "Shoff" is
205 * the section header offset within the file. Since that table is
206 * after the new .data section, it is moved. "Shnum" is the number of
207 * sections, which we increment.
209 * "Phoff" is the file offset to the program header. "Phentsize" and
210 * "Shentsz" are the program and section header entries sizes respectively.
211 * These can be larger than the apparent struct sizes.
213 raid:/nfs/raid/src/dist-18.56/src> dump -f temacs
218 Class Data Type Machine Version
219 Entry Phoff Shoff Flags Ehsize
220 Phentsize Phnum Shentsz Shnum Shstrndx
223 0x80499cc 0x34 0x792f4 0 0x34
226 raid:/nfs/raid/src/dist-18.56/src> dump -f xemacs
231 Class Data Type Machine Version
232 Entry Phoff Shoff Flags Ehsize
233 Phentsize Phnum Shentsz Shnum Shstrndx
236 0x80499cc 0x34 0x96200 0 0x34
239 * These are the program headers. "Offset" is the file offset to the
240 * segment. "Vaddr" is the memory load address. "Filesz" is the
241 * segment size as it appears in the file, and "Memsz" is the size in
242 * memory. Below, the third segment is the code and the fourth is the
243 * data: the difference between Filesz and Memsz is .bss
245 raid:/nfs/raid/src/dist-18.56/src> dump -o temacs
248 ***** PROGRAM EXECUTION HEADER *****
249 Type Offset Vaddr Paddr
250 Filesz Memsz Flags Align
259 0x3f2f9 0x3f2f9 5 0x1000
261 1 0x3f330 0x8088330 0
262 0x215c4 0x25a60 7 0x1000
264 2 0x60874 0x80a9874 0
267 raid:/nfs/raid/src/dist-18.56/src> dump -o xemacs
270 ***** PROGRAM EXECUTION HEADER *****
271 Type Offset Vaddr Paddr
272 Filesz Memsz Flags Align
281 0x3f2f9 0x3f2f9 5 0x1000
283 1 0x3f330 0x8088330 0
284 0x3e4d0 0x3e4d0 7 0x1000
286 2 0x60874 0x80a9874 0
292 /* Modified by wtien@urbana.mcd.mot.com of Motorola Inc.
294 * The above mechanism does not work if the unexeced ELF file is being
295 * re-layout by other applications (such as `strip'). All the applications
296 * that re-layout the internal of ELF will layout all sections in ascending
297 * order of their file offsets. After the re-layout, the data2 section will
298 * still be the LAST section in the section header vector, but its file offset
299 * is now being pushed far away down, and causes part of it not to be mapped
300 * in (ie. not covered by the load segment entry in PHDR vector), therefore
301 * causes the new binary to fail.
303 * The solution is to modify the unexec algorithm to insert the new data2
304 * section header right before the new bss section header, so their file
305 * offsets will be in the ascending order. Since some of the section's (all
306 * sections AFTER the bss section) indexes are now changed, we also need to
307 * modify some fields to make them point to the right sections. This is done
308 * by macro PATCH_INDEX. All the fields that need to be patched are:
310 * 1. ELF header e_shstrndx field.
311 * 2. section header sh_link and sh_info field.
312 * 3. symbol table entry st_shndx field.
314 * The above example now should look like:
316 **** SECTION HEADER TABLE ****
317 [No] Type Flags Addr Offset Size Name
318 Link Info Adralgn Entsize
320 [1] 1 2 0x80480d4 0xd4 0x13 .interp
323 [2] 5 2 0x80480e8 0xe8 0x388 .hash
326 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
329 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
332 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
335 [6] 1 6 0x8049348 0x1348 0x3 .init
338 [7] 1 6 0x804934c 0x134c 0x680 .plt
341 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
344 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
347 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
350 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
353 [12] 1 3 0x8088330 0x3f330 0x20afc .data
356 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
359 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
362 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
365 [16] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
368 [17] 8 3 0x80c6800 0x7d800 0 .bss
371 [18] 2 0 0 0x7d800 0x9b90 .symtab
374 [19] 3 0 0 0x87390 0x8526 .strtab
377 [20] 3 0 0 0x8f8b6 0x93 .shstrtab
380 [21] 1 0 0 0x8f949 0x68b7 .comment
385 /* We do not use mmap because that fails with NFS.
386 Instead we read the whole file, modify it, and write it out. */
391 extern void fatal (const char *msgid
, ...);
393 #include <sys/types.h>
396 #include <sys/stat.h>
401 #if !defined (__NetBSD__) && !defined (__OpenBSD__)
403 #endif /* not __NetBSD__ and not __OpenBSD__ */
404 #include <sys/mman.h>
405 #if defined (_SYSTYPE_SYSV)
406 #include <sys/elf_mips.h>
408 #endif /* _SYSTYPE_SYSV */
410 #include <syms.h> /* for HDRR declaration */
415 #define MAP_ANON MAP_ANONYMOUS
422 #define MAP_FAILED ((void *) -1)
425 #if defined (__alpha__) && !defined (__NetBSD__) && !defined (__OpenBSD__)
426 /* Declare COFF debugging symbol table. This used to be in
427 /usr/include/sym.h, but this file is no longer included in Red Hat
428 5.0 and presumably in any other glibc 2.x based distribution. */
456 #define cbHDRR sizeof (HDRR)
457 #define hdrNil ((pHDRR)0)
462 * NetBSD does not have normal-looking user-land ELF support.
464 # if defined __alpha__ || defined __sparc_v9__
469 # include <sys/exec_elf.h>
472 # define PT_LOAD Elf_pt_load
473 # if 0 /* was in pkgsrc patches for 20.7 */
474 # define SHT_PROGBITS Elf_sht_progbits
476 # define SHT_SYMTAB Elf_sht_symtab
477 # define SHT_DYNSYM Elf_sht_dynsym
478 # define SHT_NULL Elf_sht_null
479 # define SHT_NOBITS Elf_sht_nobits
480 # define SHT_REL Elf_sht_rel
481 # define SHT_RELA Elf_sht_rela
483 # define SHN_UNDEF Elf_eshn_undefined
484 # define SHN_ABS Elf_eshn_absolute
485 # define SHN_COMMON Elf_eshn_common
486 # endif /* !PT_LOAD */
489 # include <sys/exec_ecoff.h>
490 # define HDRR struct ecoff_symhdr
491 # define pHDRR HDRR *
492 # endif /* __alpha__ */
494 #ifdef __mips__ /* was in pkgsrc patches for 20.7 */
495 # define SHT_MIPS_DEBUG DT_MIPS_FLAGS
496 # define HDRR struct Elf_Shdr
497 #endif /* __mips__ */
498 #endif /* __NetBSD__ */
501 # include <sys/exec_elf.h>
504 #if __GNU_LIBRARY__ - 0 >= 6
505 # include <link.h> /* get ElfW etc */
510 # define ElfBitsW(bits, type) Elf##bits##_##type
512 # define ElfBitsW(bits, type) Elf/**/bits/**/_/**/type
519 /* This macro expands `bits' before invoking ElfBitsW. */
520 # define ElfExpandBitsW(bits, type) ElfBitsW (bits, type)
521 # define ElfW(type) ElfExpandBitsW (ELFSIZE, type)
524 /* Get the address of a particular section or program header entry,
525 * accounting for the size of the entries.
528 On PPC Reference Platform running Solaris 2.5.1
529 the plt section is also of type NOBI like the bss section.
530 (not really stored) and therefore sections after the bss
531 section start at the plt offset. The plt section is always
532 the one just before the bss section.
533 Thus, we modify the test from
534 if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset)
536 if (NEW_SECTION_H (nn).sh_offset >=
537 OLD_SECTION_H (old_bss_index-1).sh_offset)
538 This is just a hack. We should put the new data section
539 before the .plt section.
540 And we should not have this routine at all but use
541 the libelf library to read the old file and create the new
543 The changed code is minimal and depends on prep set in m/prep.h
545 Quantum Theory Project
546 University of Florida
551 #define OLD_SECTION_H(n) \
552 (*(ElfW (Shdr) *) ((byte *) old_section_h + old_file_h->e_shentsize * (n)))
553 #define NEW_SECTION_H(n) \
554 (*(ElfW (Shdr) *) ((byte *) new_section_h + new_file_h->e_shentsize * (n)))
555 #define NEW_PROGRAM_H(n) \
556 (*(ElfW (Phdr) *) ((byte *) new_program_h + new_file_h->e_phentsize * (n)))
558 #define PATCH_INDEX(n) \
560 if ((int) (n) >= old_bss_index) \
562 typedef unsigned char byte
;
564 /* Round X up to a multiple of Y. */
567 round_up (ElfW (Addr
) x
, ElfW (Addr
) y
)
575 /* Return the index of the section named NAME.
576 SECTION_NAMES, FILE_NAME and FILE_H give information
577 about the file we are looking in.
579 If we don't find the section NAME, that is a fatal error
580 if NOERROR is 0; we return -1 if NOERROR is nonzero. */
583 find_section (const char *name
, const char *section_names
, const char *file_name
,
584 ElfW (Ehdr
) *old_file_h
, ElfW (Shdr
) *old_section_h
, int noerror
)
588 for (idx
= 1; idx
< old_file_h
->e_shnum
; idx
++)
591 fprintf (stderr
, "Looking for %s - found %s\n", name
,
592 section_names
+ OLD_SECTION_H (idx
).sh_name
);
594 if (!strcmp (section_names
+ OLD_SECTION_H (idx
).sh_name
,
598 if (idx
== old_file_h
->e_shnum
)
603 fatal ("Can't find %s in %s.\n", name
, file_name
);
609 /* ****************************************************************
614 * In ELF, this works by replacing the old .bss section with a new
615 * .data section, and inserting an empty .bss immediately afterwards.
619 unexec (const char *new_name
, const char *old_name
)
621 int new_file
, old_file
, new_file_size
;
623 #if defined (emacs) || !defined (DEBUG)
627 /* Pointers to the base of the image of the two files. */
628 caddr_t old_base
, new_base
;
636 /* Pointers to the file, program and section headers for the old and
638 ElfW (Ehdr
) *old_file_h
, *new_file_h
;
639 ElfW (Phdr
) *old_program_h
, *new_program_h
;
640 ElfW (Shdr
) *old_section_h
, *new_section_h
;
642 /* Point to the section name table in the old file. */
643 char *old_section_names
;
645 ElfW (Addr
) old_bss_addr
, new_bss_addr
;
646 ElfW (Word
) old_bss_size
, new_data2_size
;
647 ElfW (Off
) new_data2_offset
;
648 ElfW (Addr
) new_data2_addr
;
649 ElfW (Off
) old_bss_offset
;
650 ElfW (Word
) new_data2_incr
;
653 int old_bss_index
, old_sbss_index
, old_plt_index
;
654 int old_data_index
, new_data2_index
;
655 #if defined _SYSTYPE_SYSV || defined __sgi
656 int old_mdebug_index
;
658 struct stat stat_buf
;
661 /* Open the old file, allocate a buffer of the right size, and read
662 in the file contents. */
664 old_file
= open (old_name
, O_RDONLY
);
667 fatal ("Can't open %s for reading: errno %d\n", old_name
, errno
);
669 if (fstat (old_file
, &stat_buf
) == -1)
670 fatal ("Can't fstat (%s): errno %d\n", old_name
, errno
);
673 mmap_fd
= open ("/dev/zero", O_RDONLY
);
675 fatal ("Can't open /dev/zero for reading: errno %d\n", errno
, 0);
678 /* We cannot use malloc here because that may use sbrk. If it does,
679 we'd dump our temporary buffers with Emacs, and we'd have to be
680 extra careful to use the correct value of sbrk(0) after
681 allocating all buffers in the code below, which we aren't. */
682 old_file_size
= stat_buf
.st_size
;
683 old_base
= mmap (NULL
, old_file_size
, PROT_READ
| PROT_WRITE
,
684 MAP_ANON
| MAP_PRIVATE
, mmap_fd
, 0);
685 if (old_base
== MAP_FAILED
)
686 fatal ("Can't allocate buffer for %s\n", old_name
, 0);
688 if (read (old_file
, old_base
, stat_buf
.st_size
) != stat_buf
.st_size
)
689 fatal ("Didn't read all of %s: errno %d\n", old_name
, errno
);
691 /* Get pointers to headers & section names */
693 old_file_h
= (ElfW (Ehdr
) *) old_base
;
694 old_program_h
= (ElfW (Phdr
) *) ((byte
*) old_base
+ old_file_h
->e_phoff
);
695 old_section_h
= (ElfW (Shdr
) *) ((byte
*) old_base
+ old_file_h
->e_shoff
);
696 old_section_names
= (char *) old_base
697 + OLD_SECTION_H (old_file_h
->e_shstrndx
).sh_offset
;
699 /* Find the mdebug section, if any. */
701 #if defined _SYSTYPE_SYSV || defined __sgi
702 old_mdebug_index
= find_section (".mdebug", old_section_names
,
703 old_name
, old_file_h
, old_section_h
, 1);
706 /* Find the old .bss section. Figure out parameters of the new
707 data2 and bss sections. */
709 old_bss_index
= find_section (".bss", old_section_names
,
710 old_name
, old_file_h
, old_section_h
, 0);
712 old_sbss_index
= find_section (".sbss", old_section_names
,
713 old_name
, old_file_h
, old_section_h
, 1);
714 if (old_sbss_index
!= -1)
715 if (OLD_SECTION_H (old_sbss_index
).sh_type
!= SHT_NOBITS
)
718 /* PowerPC64 has .plt in the BSS section. */
719 old_plt_index
= find_section (".plt", old_section_names
,
720 old_name
, old_file_h
, old_section_h
, 1);
721 if (old_plt_index
!= -1)
722 if (OLD_SECTION_H (old_plt_index
).sh_type
!= SHT_NOBITS
)
725 if (old_sbss_index
== -1 && old_plt_index
== -1)
727 old_bss_addr
= OLD_SECTION_H (old_bss_index
).sh_addr
;
728 old_bss_size
= OLD_SECTION_H (old_bss_index
).sh_size
;
729 old_bss_offset
= OLD_SECTION_H (old_bss_index
).sh_offset
;
730 new_data2_index
= old_bss_index
;
732 else if (old_plt_index
!= -1
733 && (old_sbss_index
== -1
734 || (OLD_SECTION_H (old_sbss_index
).sh_addr
735 > OLD_SECTION_H (old_plt_index
).sh_addr
)))
737 old_bss_addr
= OLD_SECTION_H (old_plt_index
).sh_addr
;
738 old_bss_size
= OLD_SECTION_H (old_bss_index
).sh_size
739 + OLD_SECTION_H (old_plt_index
).sh_size
;
740 if (old_sbss_index
!= -1)
741 old_bss_size
+= OLD_SECTION_H (old_sbss_index
).sh_size
;
742 old_bss_offset
= OLD_SECTION_H (old_plt_index
).sh_offset
;
743 new_data2_index
= old_plt_index
;
747 old_bss_addr
= OLD_SECTION_H (old_sbss_index
).sh_addr
;
748 old_bss_size
= OLD_SECTION_H (old_bss_index
).sh_size
749 + OLD_SECTION_H (old_sbss_index
).sh_size
;
750 old_bss_offset
= OLD_SECTION_H (old_sbss_index
).sh_offset
;
751 new_data2_index
= old_sbss_index
;
754 /* Find the old .data section. Figure out parameters of
755 the new data2 and bss sections. */
757 old_data_index
= find_section (".data", old_section_names
,
758 old_name
, old_file_h
, old_section_h
, 0);
760 #if defined (emacs) || !defined (DEBUG)
761 new_break
= sbrk (0);
762 new_bss_addr
= (ElfW (Addr
)) new_break
;
764 new_bss_addr
= old_bss_addr
+ old_bss_size
+ 0x1234;
766 new_data2_addr
= old_bss_addr
;
767 new_data2_size
= new_bss_addr
- old_bss_addr
;
768 new_data2_offset
= OLD_SECTION_H (old_data_index
).sh_offset
769 + (new_data2_addr
- OLD_SECTION_H (old_data_index
).sh_addr
);
770 /* This is the amount by which the sections following the bss sections
771 must be shifted in the image. It can differ from new_data2_size if
772 the end of the old .data section (and thus the offset of the .bss
773 section) was unaligned. */
774 new_data2_incr
= new_data2_size
+ (new_data2_offset
- old_bss_offset
);
777 fprintf (stderr
, "old_bss_index %d\n", old_bss_index
);
778 fprintf (stderr
, "old_bss_addr %x\n", old_bss_addr
);
779 fprintf (stderr
, "old_bss_size %x\n", old_bss_size
);
780 fprintf (stderr
, "old_bss_offset %x\n", old_bss_offset
);
781 fprintf (stderr
, "new_bss_addr %x\n", new_bss_addr
);
782 fprintf (stderr
, "new_data2_addr %x\n", new_data2_addr
);
783 fprintf (stderr
, "new_data2_size %x\n", new_data2_size
);
784 fprintf (stderr
, "new_data2_offset %x\n", new_data2_offset
);
785 fprintf (stderr
, "new_data2_incr %x\n", new_data2_incr
);
788 if ((uintptr_t) new_bss_addr
< (uintptr_t) old_bss_addr
+ old_bss_size
)
789 fatal (".bss shrank when undumping???\n", 0, 0);
791 /* Set the output file to the right size. Allocate a buffer to hold
792 the image of the new file. Set pointers to various interesting
793 objects. stat_buf still has old_file data. */
795 new_file
= open (new_name
, O_RDWR
| O_CREAT
, 0666);
797 fatal ("Can't creat (%s): errno %d\n", new_name
, errno
);
799 new_file_size
= stat_buf
.st_size
+ old_file_h
->e_shentsize
+ new_data2_incr
;
801 if (ftruncate (new_file
, new_file_size
))
802 fatal ("Can't ftruncate (%s): errno %d\n", new_name
, errno
);
804 new_base
= mmap (NULL
, new_file_size
, PROT_READ
| PROT_WRITE
,
805 MAP_ANON
| MAP_PRIVATE
, mmap_fd
, 0);
806 if (new_base
== MAP_FAILED
)
807 fatal ("Can't allocate buffer for %s\n", old_name
, 0);
809 new_file_h
= (ElfW (Ehdr
) *) new_base
;
810 new_program_h
= (ElfW (Phdr
) *) ((byte
*) new_base
+ old_file_h
->e_phoff
);
811 new_section_h
= (ElfW (Shdr
) *)
812 ((byte
*) new_base
+ old_file_h
->e_shoff
+ new_data2_incr
);
814 /* Make our new file, program and section headers as copies of the
817 memcpy (new_file_h
, old_file_h
, old_file_h
->e_ehsize
);
818 memcpy (new_program_h
, old_program_h
,
819 old_file_h
->e_phnum
* old_file_h
->e_phentsize
);
821 /* Modify the e_shstrndx if necessary. */
822 PATCH_INDEX (new_file_h
->e_shstrndx
);
824 /* Fix up file header. We'll add one section. Section header is
827 new_file_h
->e_shoff
+= new_data2_incr
;
828 new_file_h
->e_shnum
+= 1;
831 fprintf (stderr
, "Old section offset %x\n", old_file_h
->e_shoff
);
832 fprintf (stderr
, "Old section count %d\n", old_file_h
->e_shnum
);
833 fprintf (stderr
, "New section offset %x\n", new_file_h
->e_shoff
);
834 fprintf (stderr
, "New section count %d\n", new_file_h
->e_shnum
);
837 /* Fix up a new program header. Extend the writable data segment so
838 that the bss area is covered too. Find that segment by looking
839 for a segment that ends just before the .bss area. Make sure
840 that no segments are above the new .data2. Put a loop at the end
841 to adjust the offset and address of any segment that is above
842 data2, just in case we decide to allow this later. */
844 for (n
= new_file_h
->e_phnum
- 1; n
>= 0; n
--)
846 /* Compute maximum of all requirements for alignment of section. */
847 ElfW (Word
) alignment
= (NEW_PROGRAM_H (n
)).p_align
;
848 if ((OLD_SECTION_H (old_bss_index
)).sh_addralign
> alignment
)
849 alignment
= OLD_SECTION_H (old_bss_index
).sh_addralign
;
852 /* According to r02kar@x4u2.desy.de (Karsten Kuenne)
853 and oliva@gnu.org (Alexandre Oliva), on IRIX 5.2, we
854 always get "Program segment above .bss" when dumping
855 when the executable doesn't have an sbss section. */
856 if (old_sbss_index
!= -1)
858 if (NEW_PROGRAM_H (n
).p_vaddr
+ NEW_PROGRAM_H (n
).p_filesz
859 > (old_sbss_index
== -1
861 : round_up (old_bss_addr
, alignment
)))
862 fatal ("Program segment above .bss in %s\n", old_name
, 0);
864 if (NEW_PROGRAM_H (n
).p_type
== PT_LOAD
865 && (round_up ((NEW_PROGRAM_H (n
)).p_vaddr
866 + (NEW_PROGRAM_H (n
)).p_filesz
,
868 == round_up (old_bss_addr
, alignment
)))
872 fatal ("Couldn't find segment next to .bss in %s\n", old_name
, 0);
874 /* Make sure that the size includes any padding before the old .bss
876 NEW_PROGRAM_H (n
).p_filesz
= new_bss_addr
- NEW_PROGRAM_H (n
).p_vaddr
;
877 NEW_PROGRAM_H (n
).p_memsz
= NEW_PROGRAM_H (n
).p_filesz
;
879 #if 0 /* Maybe allow section after data2 - does this ever happen? */
880 for (n
= new_file_h
->e_phnum
- 1; n
>= 0; n
--)
882 if (NEW_PROGRAM_H (n
).p_vaddr
883 && NEW_PROGRAM_H (n
).p_vaddr
>= new_data2_addr
)
884 NEW_PROGRAM_H (n
).p_vaddr
+= new_data2_size
- old_bss_size
;
886 if (NEW_PROGRAM_H (n
).p_offset
>= new_data2_offset
)
887 NEW_PROGRAM_H (n
).p_offset
+= new_data2_incr
;
891 /* Fix up section headers based on new .data2 section. Any section
892 whose offset or virtual address is after the new .data2 section
893 gets its value adjusted. .bss size becomes zero and new address
894 is set. data2 section header gets added by copying the existing
895 .data header and modifying the offset, address and size. */
897 /* Walk through all section headers, insert the new data2 section right
898 before the new bss section. */
899 for (n
= 1, nn
= 1; n
< (int) old_file_h
->e_shnum
; n
++, nn
++)
902 /* If it is (s)bss section, insert the new data2 section before it. */
903 /* new_data2_index is the index of either old_sbss or old_bss, that was
904 chosen as a section for new_data2. */
905 if (n
== new_data2_index
)
907 /* Steal the data section header for this data2 section. */
908 memcpy (&NEW_SECTION_H (nn
), &OLD_SECTION_H (old_data_index
),
909 new_file_h
->e_shentsize
);
911 NEW_SECTION_H (nn
).sh_addr
= new_data2_addr
;
912 NEW_SECTION_H (nn
).sh_offset
= new_data2_offset
;
913 NEW_SECTION_H (nn
).sh_size
= new_data2_size
;
914 /* Use the bss section's alignment. This will assure that the
915 new data2 section always be placed in the same spot as the old
916 bss section by any other application. */
917 NEW_SECTION_H (nn
).sh_addralign
= OLD_SECTION_H (n
).sh_addralign
;
919 /* Now copy over what we have in the memory now. */
920 memcpy (NEW_SECTION_H (nn
).sh_offset
+ new_base
,
921 (caddr_t
) OLD_SECTION_H (n
).sh_addr
,
926 memcpy (&NEW_SECTION_H (nn
), &OLD_SECTION_H (n
),
927 old_file_h
->e_shentsize
);
929 if (n
== old_bss_index
930 /* The new bss and sbss section's size is zero, and its file offset
931 and virtual address should be off by NEW_DATA2_SIZE. */
932 || n
== old_sbss_index
|| n
== old_plt_index
935 /* NN should be `old_s?bss_index + 1' at this point. */
936 NEW_SECTION_H (nn
).sh_offset
= new_data2_offset
+ new_data2_size
;
937 NEW_SECTION_H (nn
).sh_addr
= new_data2_addr
+ new_data2_size
;
938 /* Let the new bss section address alignment be the same as the
939 section address alignment followed the old bss section, so
940 this section will be placed in exactly the same place. */
941 NEW_SECTION_H (nn
).sh_addralign
= OLD_SECTION_H (nn
).sh_addralign
;
942 NEW_SECTION_H (nn
).sh_size
= 0;
946 /* Any section that was originally placed after the .bss
947 section should now be off by NEW_DATA2_INCR. If a
948 section overlaps the .bss section, consider it to be
949 placed after the .bss section. Overlap can occur if the
950 section just before .bss has less-strict alignment; this
951 was observed between .symtab and .bss on Solaris 2.5.1
952 (sparc) with GCC snapshot 960602.
958 **** SECTION HEADER TABLE ****
959 [No] Type Flags Addr Offset Size Name
960 Link Info Adralgn Entsize
962 [22] 1 3 0x335150 0x315150 0x4 .data.rel.local
965 [23] 8 3 0x335158 0x315158 0x42720 .bss
968 [24] 2 0 0 0x315154 0x1c9d0 .symtab
972 if (NEW_SECTION_H (nn
).sh_offset
>= old_bss_offset
973 || (NEW_SECTION_H (nn
).sh_offset
+ NEW_SECTION_H (nn
).sh_size
975 NEW_SECTION_H (nn
).sh_offset
+= new_data2_incr
;
977 /* Any section that was originally placed after the section
978 header table should now be off by the size of one section
979 header table entry. */
980 if (NEW_SECTION_H (nn
).sh_offset
> new_file_h
->e_shoff
)
981 NEW_SECTION_H (nn
).sh_offset
+= new_file_h
->e_shentsize
;
984 /* If any section hdr refers to the section after the new .data
985 section, make it refer to next one because we have inserted
986 a new section in between. */
988 PATCH_INDEX (NEW_SECTION_H (nn
).sh_link
);
989 /* For symbol tables, info is a symbol table index,
990 so don't change it. */
991 if (NEW_SECTION_H (nn
).sh_type
!= SHT_SYMTAB
992 && NEW_SECTION_H (nn
).sh_type
!= SHT_DYNSYM
)
993 PATCH_INDEX (NEW_SECTION_H (nn
).sh_info
);
995 if (old_sbss_index
!= -1)
996 if (!strcmp (old_section_names
+ NEW_SECTION_H (nn
).sh_name
, ".sbss"))
998 NEW_SECTION_H (nn
).sh_offset
=
999 round_up (NEW_SECTION_H (nn
).sh_offset
,
1000 NEW_SECTION_H (nn
).sh_addralign
);
1001 NEW_SECTION_H (nn
).sh_type
= SHT_PROGBITS
;
1004 /* Now, start to copy the content of sections. */
1005 if (NEW_SECTION_H (nn
).sh_type
== SHT_NULL
1006 || NEW_SECTION_H (nn
).sh_type
== SHT_NOBITS
)
1009 /* Write out the sections. .data and .data1 (and data2, called
1010 ".data" in the strings table) get copied from the current process
1011 instead of the old file. */
1012 if (!strcmp (old_section_names
+ NEW_SECTION_H (n
).sh_name
, ".data")
1013 || !strcmp ((old_section_names
+ NEW_SECTION_H (n
).sh_name
),
1015 || !strcmp ((old_section_names
+ NEW_SECTION_H (n
).sh_name
),
1017 || !strcmp ((old_section_names
+ NEW_SECTION_H (n
).sh_name
),
1019 /* The conditional bit below was in Oliva's original code
1020 (1999-08-25) and seems to have been dropped by mistake
1021 subsequently. It prevents a crash at startup under X in
1022 `IRIX64 6.5 6.5.17m', whether compiled on that release or
1023 an earlier one. It causes no trouble on the other ELF
1024 platforms I could test (Irix 6.5.15m, Solaris 8, Debian
1025 Potato x86, Debian Woody SPARC); however, it's reported
1026 to cause crashes under some version of GNU/Linux. It's
1027 not yet clear what's changed in that Irix version to
1028 cause the problem, or why the fix sometimes fails under
1029 GNU/Linux. There's probably no good reason to have
1030 something Irix-specific here, but this will have to do
1031 for now. IRIX6_5 is the most specific macro we have to
1032 test. -- fx 2002-10-01
1034 The issue _looks_ as though it's gone away on 6.5.18m,
1035 but maybe it's still lurking, to be triggered by some
1036 change in the binary. It appears to concern the dynamic
1037 loader, but I never got anywhere with an SGI support call
1038 seeking clues. -- fx 2002-11-29. */
1040 || !strcmp ((old_section_names
+ NEW_SECTION_H (n
).sh_name
),
1043 || !strcmp ((old_section_names
+ NEW_SECTION_H (n
).sh_name
),
1045 || !strcmp ((old_section_names
+ NEW_SECTION_H (n
).sh_name
),
1047 || !strcmp ((old_section_names
+ NEW_SECTION_H (n
).sh_name
),
1049 src
= (caddr_t
) OLD_SECTION_H (n
).sh_addr
;
1051 src
= old_base
+ OLD_SECTION_H (n
).sh_offset
;
1053 memcpy (NEW_SECTION_H (nn
).sh_offset
+ new_base
, src
,
1054 NEW_SECTION_H (nn
).sh_size
);
1056 #if defined __alpha__ && !defined __OpenBSD__
1057 /* Update Alpha COFF symbol table: */
1058 if (strcmp (old_section_names
+ OLD_SECTION_H (n
).sh_name
, ".mdebug")
1061 pHDRR symhdr
= (pHDRR
) (NEW_SECTION_H (nn
).sh_offset
+ new_base
);
1063 symhdr
->cbLineOffset
+= new_data2_size
;
1064 symhdr
->cbDnOffset
+= new_data2_size
;
1065 symhdr
->cbPdOffset
+= new_data2_size
;
1066 symhdr
->cbSymOffset
+= new_data2_size
;
1067 symhdr
->cbOptOffset
+= new_data2_size
;
1068 symhdr
->cbAuxOffset
+= new_data2_size
;
1069 symhdr
->cbSsOffset
+= new_data2_size
;
1070 symhdr
->cbSsExtOffset
+= new_data2_size
;
1071 symhdr
->cbFdOffset
+= new_data2_size
;
1072 symhdr
->cbRfdOffset
+= new_data2_size
;
1073 symhdr
->cbExtOffset
+= new_data2_size
;
1075 #endif /* __alpha__ && !__OpenBSD__ */
1077 #if defined (_SYSTYPE_SYSV)
1078 if (NEW_SECTION_H (nn
).sh_type
== SHT_MIPS_DEBUG
1079 && old_mdebug_index
!= -1)
1081 int diff
= NEW_SECTION_H (nn
).sh_offset
1082 - OLD_SECTION_H (old_mdebug_index
).sh_offset
;
1083 HDRR
*phdr
= (HDRR
*)(NEW_SECTION_H (nn
).sh_offset
+ new_base
);
1087 phdr
->cbLineOffset
+= diff
;
1088 phdr
->cbDnOffset
+= diff
;
1089 phdr
->cbPdOffset
+= diff
;
1090 phdr
->cbSymOffset
+= diff
;
1091 phdr
->cbOptOffset
+= diff
;
1092 phdr
->cbAuxOffset
+= diff
;
1093 phdr
->cbSsOffset
+= diff
;
1094 phdr
->cbSsExtOffset
+= diff
;
1095 phdr
->cbFdOffset
+= diff
;
1096 phdr
->cbRfdOffset
+= diff
;
1097 phdr
->cbExtOffset
+= diff
;
1100 #endif /* _SYSTYPE_SYSV */
1103 /* Adjust the HDRR offsets in .mdebug and copy the
1104 line data if it's in its usual 'hole' in the object.
1105 Makes the new file debuggable with dbx.
1106 patches up two problems: the absolute file offsets
1107 in the HDRR record of .mdebug (see /usr/include/syms.h), and
1108 the ld bug that gets the line table in a hole in the
1109 elf file rather than in the .mdebug section proper.
1110 David Anderson. davea@sgi.com Jan 16,1994. */
1111 if (n
== old_mdebug_index
)
1113 #define MDEBUGADJUST(__ct,__fileaddr) \
1114 if (n_phdrr->__ct > 0) \
1116 n_phdrr->__fileaddr += movement; \
1119 HDRR
* o_phdrr
= (HDRR
*)((byte
*)old_base
+ OLD_SECTION_H (n
).sh_offset
);
1120 HDRR
* n_phdrr
= (HDRR
*)((byte
*)new_base
+ NEW_SECTION_H (nn
).sh_offset
);
1121 unsigned movement
= new_data2_size
;
1123 MDEBUGADJUST (idnMax
, cbDnOffset
);
1124 MDEBUGADJUST (ipdMax
, cbPdOffset
);
1125 MDEBUGADJUST (isymMax
, cbSymOffset
);
1126 MDEBUGADJUST (ioptMax
, cbOptOffset
);
1127 MDEBUGADJUST (iauxMax
, cbAuxOffset
);
1128 MDEBUGADJUST (issMax
, cbSsOffset
);
1129 MDEBUGADJUST (issExtMax
, cbSsExtOffset
);
1130 MDEBUGADJUST (ifdMax
, cbFdOffset
);
1131 MDEBUGADJUST (crfd
, cbRfdOffset
);
1132 MDEBUGADJUST (iextMax
, cbExtOffset
);
1133 /* The Line Section, being possible off in a hole of the object,
1134 requires special handling. */
1135 if (n_phdrr
->cbLine
> 0)
1137 if (o_phdrr
->cbLineOffset
> (OLD_SECTION_H (n
).sh_offset
1138 + OLD_SECTION_H (n
).sh_size
))
1140 /* line data is in a hole in elf. do special copy and adjust
1141 for this ld mistake.
1143 n_phdrr
->cbLineOffset
+= movement
;
1145 memcpy (n_phdrr
->cbLineOffset
+ new_base
,
1146 o_phdrr
->cbLineOffset
+ old_base
, n_phdrr
->cbLine
);
1150 /* somehow line data is in .mdebug as it is supposed to be. */
1151 MDEBUGADJUST (cbLine
, cbLineOffset
);
1157 /* If it is the symbol table, its st_shndx field needs to be patched. */
1158 if (NEW_SECTION_H (nn
).sh_type
== SHT_SYMTAB
1159 || NEW_SECTION_H (nn
).sh_type
== SHT_DYNSYM
)
1161 ElfW (Shdr
) *spt
= &NEW_SECTION_H (nn
);
1162 unsigned int num
= spt
->sh_size
/ spt
->sh_entsize
;
1163 ElfW (Sym
) * sym
= (ElfW (Sym
) *) (NEW_SECTION_H (nn
).sh_offset
+
1165 for (; num
--; sym
++)
1167 if ((sym
->st_shndx
== SHN_UNDEF
)
1168 || (sym
->st_shndx
== SHN_ABS
)
1169 || (sym
->st_shndx
== SHN_COMMON
))
1172 PATCH_INDEX (sym
->st_shndx
);
1177 /* Update the symbol values of _edata and _end. */
1178 for (n
= new_file_h
->e_shnum
- 1; n
; n
--)
1181 ElfW (Sym
) *symp
, *symendp
;
1183 if (NEW_SECTION_H (n
).sh_type
!= SHT_DYNSYM
1184 && NEW_SECTION_H (n
).sh_type
!= SHT_SYMTAB
)
1187 symnames
= ((byte
*) new_base
1188 + NEW_SECTION_H (NEW_SECTION_H (n
).sh_link
).sh_offset
);
1189 symp
= (ElfW (Sym
) *) (NEW_SECTION_H (n
).sh_offset
+ new_base
);
1190 symendp
= (ElfW (Sym
) *) ((byte
*)symp
+ NEW_SECTION_H (n
).sh_size
);
1192 for (; symp
< symendp
; symp
++)
1194 if (strcmp ((char *) (symnames
+ symp
->st_name
), "_end") == 0
1195 || strcmp ((char *) (symnames
+ symp
->st_name
), "end") == 0
1196 || strcmp ((char *) (symnames
+ symp
->st_name
), "_edata") == 0
1197 || strcmp ((char *) (symnames
+ symp
->st_name
), "edata") == 0)
1198 memcpy (&symp
->st_value
, &new_bss_addr
, sizeof (new_bss_addr
));
1200 /* Strictly speaking, #ifdef below is not necessary. But we
1201 keep it to indicate that this kind of change may also be
1202 necessary for other unexecs to support GNUstep. */
1203 #ifdef NS_IMPL_GNUSTEP
1204 /* ObjC runtime modifies the values of some data structures
1205 such as classes and selectors in the .data section after
1206 loading. As the dump process copies the .data section
1207 from the current process, that causes problems when the
1208 modified classes are reinitialized in the dumped
1209 executable. We copy such data from the old file, not
1210 from the current process. */
1211 if (strncmp ((char *) (symnames
+ symp
->st_name
),
1212 "_OBJC_", sizeof ("_OBJC_") - 1) == 0)
1216 new = ((symp
->st_value
- NEW_SECTION_H (symp
->st_shndx
).sh_addr
)
1217 + NEW_SECTION_H (symp
->st_shndx
).sh_offset
+ new_base
);
1218 /* "Unpatch" index. */
1219 nn
= symp
->st_shndx
;
1220 if (nn
> old_bss_index
)
1222 if (nn
== old_bss_index
)
1223 memset (new, 0, symp
->st_size
);
1226 old
= ((symp
->st_value
1227 - NEW_SECTION_H (symp
->st_shndx
).sh_addr
)
1228 + OLD_SECTION_H (nn
).sh_offset
+ old_base
);
1229 memcpy (new, old
, symp
->st_size
);
1236 /* This loop seeks out relocation sections for the data section, so
1237 that it can undo relocations performed by the runtime linker. */
1238 for (n
= new_file_h
->e_shnum
- 1; n
; n
--)
1240 ElfW (Shdr
) section
= NEW_SECTION_H (n
);
1242 /* Cause a compilation error if anyone uses n instead of nn below. */
1243 #define n ((void) 0);
1244 n
/* Prevent 'macro "n" is not used' warnings. */
1246 switch (section
.sh_type
)
1252 /* This code handles two different size structs, but there should
1253 be no harm in that provided that r_offset is always the first
1255 nn
= section
.sh_info
;
1256 if (!strcmp (old_section_names
+ NEW_SECTION_H (nn
).sh_name
, ".data")
1257 || !strcmp ((old_section_names
+ NEW_SECTION_H (nn
).sh_name
),
1259 || !strcmp ((old_section_names
+ NEW_SECTION_H (nn
).sh_name
),
1261 || !strcmp ((old_section_names
+ NEW_SECTION_H (nn
).sh_name
),
1263 #ifdef IRIX6_5 /* see above */
1264 || !strcmp ((old_section_names
+ NEW_SECTION_H (nn
).sh_name
),
1267 || !strcmp ((old_section_names
+ NEW_SECTION_H (nn
).sh_name
),
1269 || !strcmp ((old_section_names
+ NEW_SECTION_H (nn
).sh_name
),
1272 ElfW (Addr
) offset
= (NEW_SECTION_H (nn
).sh_addr
1273 - NEW_SECTION_H (nn
).sh_offset
);
1274 caddr_t reloc
= old_base
+ section
.sh_offset
, end
;
1275 for (end
= reloc
+ section
.sh_size
; reloc
< end
;
1276 reloc
+= section
.sh_entsize
)
1278 ElfW (Addr
) addr
= ((ElfW (Rel
) *) reloc
)->r_offset
- offset
;
1280 /* The Alpha ELF binutils currently have a bug that
1281 sometimes results in relocs that contain all
1282 zeroes. Work around this for now... */
1283 if (((ElfW (Rel
) *) reloc
)->r_offset
== 0)
1286 memcpy (new_base
+ addr
, old_base
+ addr
, sizeof (ElfW (Addr
)));
1295 /* Write out new_file, and free the buffers. */
1297 if (write (new_file
, new_base
, new_file_size
) != new_file_size
)
1298 fatal ("Didn't write %d bytes to %s: errno %d\n",
1299 new_file_size
, new_name
, errno
);
1300 munmap (old_base
, old_file_size
);
1301 munmap (new_base
, new_file_size
);
1303 /* Close the files and make the new file executable. */
1309 if (close (old_file
))
1310 fatal ("Can't close (%s): errno %d\n", old_name
, errno
);
1312 if (close (new_file
))
1313 fatal ("Can't close (%s): errno %d\n", new_name
, errno
);
1315 if (stat (new_name
, &stat_buf
) == -1)
1316 fatal ("Can't stat (%s): errno %d\n", new_name
, errno
);
1320 stat_buf
.st_mode
|= 0111 & ~n
;
1321 if (chmod (new_name
, stat_buf
.st_mode
) == -1)
1322 fatal ("Can't chmod (%s): errno %d\n", new_name
, errno
);