1 /* Copyright (C) 1985, 1986, 1987, 1988, 1990, 1992
2 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2, or (at your option)
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 In other words, you are welcome to use, share and improve this program.
19 You are forbidden to forbid anyone else to use, share and improve
20 what you give them. Help stamp out software-hoarding! */
24 * unexec.c - Convert a running program into an a.out file.
26 * Author: Spencer W. Thomas
27 * Computer Science Dept.
29 * Date: Tue Mar 2 1982
30 * Modified heavily since then.
33 * unexec (new_name, a_name, data_start, bss_start, entry_address)
34 * char *new_name, *a_name;
35 * unsigned data_start, bss_start, entry_address;
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 a_name is non-NULL, the symbol table will be taken from the given file.
40 * On some machines, an existing a_name file is required.
42 * The boundaries within the a.out file may be adjusted with the data_start
43 * and bss_start arguments. Either or both may be given as 0 for defaults.
45 * Data_start gives the boundary between the text segment and the data
46 * segment of the program. The text segment can contain shared, read-only
47 * program code and literal data, while the data segment is always unshared
48 * and unprotected. Data_start gives the lowest unprotected address.
49 * The value you specify may be rounded down to a suitable boundary
50 * as required by the machine you are using.
52 * Specifying zero for data_start means the boundary between text and data
53 * should not be the same as when the program was loaded.
54 * If NO_REMAP is defined, the argument data_start is ignored and the
55 * segment boundaries are never changed.
57 * Bss_start indicates how much of the data segment is to be saved in the
58 * a.out file and restored when the program is executed. It gives the lowest
59 * unsaved address, and is rounded up to a page boundary. The default when 0
60 * is given assumes that the entire data segment is to be stored, including
61 * the previous data and bss as well as any additional storage allocated with
64 * The new file is set up to start at entry_address.
66 * If you make improvements I'd like to get them too.
67 * harpo!utah-cs!thomas, thomas@Utah-20
71 /* Even more heavily modified by james@bigtex.cactus.org of Dell Computer Co.
74 * Basic theory: the data space of the running process needs to be
75 * dumped to the output file. Normally we would just enlarge the size
76 * of .data, scooting everything down. But we can't do that in ELF,
77 * because there is often something between the .data space and the
80 * In the temacs dump below, notice that the Global Offset Table
81 * (.got) and the Dynamic link data (.dynamic) come between .data1 and
82 * .bss. It does not work to overlap .data with these fields.
84 * The solution is to create a new .data segment. This segment is
85 * filled with data from the current process. Since the contents of
86 * various sections refer to sections by index, the new .data segment
87 * is made the last in the table to avoid changing any existing index.
89 * This is an example of how the section headers are changed. "Addr"
90 * is a process virtual address. "Offset" is a file offset.
92 raid:/nfs/raid/src/dist-18.56/src> dump -h temacs
96 **** SECTION HEADER TABLE ****
97 [No] Type Flags Addr Offset Size Name
98 Link Info Adralgn Entsize
100 [1] 1 2 0x80480d4 0xd4 0x13 .interp
103 [2] 5 2 0x80480e8 0xe8 0x388 .hash
106 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
109 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
112 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
115 [6] 1 6 0x8049348 0x1348 0x3 .init
118 [7] 1 6 0x804934c 0x134c 0x680 .plt
121 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
124 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
127 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
130 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
133 [12] 1 3 0x8088330 0x3f330 0x20afc .data
136 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
139 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
142 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
145 [16] 8 3 0x80a98f4 0x608f4 0x449c .bss
148 [17] 2 0 0 0x608f4 0x9b90 .symtab
151 [18] 3 0 0 0x6a484 0x8526 .strtab
154 [19] 3 0 0 0x729aa 0x93 .shstrtab
157 [20] 1 0 0 0x72a3d 0x68b7 .comment
160 raid:/nfs/raid/src/dist-18.56/src> dump -h xemacs
164 **** SECTION HEADER TABLE ****
165 [No] Type Flags Addr Offset Size Name
166 Link Info Adralgn Entsize
168 [1] 1 2 0x80480d4 0xd4 0x13 .interp
171 [2] 5 2 0x80480e8 0xe8 0x388 .hash
174 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
177 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
180 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
183 [6] 1 6 0x8049348 0x1348 0x3 .init
186 [7] 1 6 0x804934c 0x134c 0x680 .plt
189 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
192 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
195 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
198 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
201 [12] 1 3 0x8088330 0x3f330 0x20afc .data
204 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
207 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
210 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
213 [16] 8 3 0x80c6800 0x7d800 0 .bss
216 [17] 2 0 0 0x7d800 0x9b90 .symtab
219 [18] 3 0 0 0x87390 0x8526 .strtab
222 [19] 3 0 0 0x8f8b6 0x93 .shstrtab
225 [20] 1 0 0 0x8f949 0x68b7 .comment
228 [21] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
231 * This is an example of how the file header is changed. "Shoff" is
232 * the section header offset within the file. Since that table is
233 * after the new .data section, it is moved. "Shnum" is the number of
234 * sections, which we increment.
236 * "Phoff" is the file offset to the program header. "Phentsize" and
237 * "Shentsz" are the program and section header entries sizes respectively.
238 * These can be larger than the apparent struct sizes.
240 raid:/nfs/raid/src/dist-18.56/src> dump -f temacs
245 Class Data Type Machine Version
246 Entry Phoff Shoff Flags Ehsize
247 Phentsize Phnum Shentsz Shnum Shstrndx
250 0x80499cc 0x34 0x792f4 0 0x34
253 raid:/nfs/raid/src/dist-18.56/src> dump -f xemacs
258 Class Data Type Machine Version
259 Entry Phoff Shoff Flags Ehsize
260 Phentsize Phnum Shentsz Shnum Shstrndx
263 0x80499cc 0x34 0x96200 0 0x34
266 * These are the program headers. "Offset" is the file offset to the
267 * segment. "Vaddr" is the memory load address. "Filesz" is the
268 * segment size as it appears in the file, and "Memsz" is the size in
269 * memory. Below, the third segment is the code and the fourth is the
270 * data: the difference between Filesz and Memsz is .bss
272 raid:/nfs/raid/src/dist-18.56/src> dump -o temacs
275 ***** PROGRAM EXECUTION HEADER *****
276 Type Offset Vaddr Paddr
277 Filesz Memsz Flags Align
286 0x3f2f9 0x3f2f9 5 0x1000
288 1 0x3f330 0x8088330 0
289 0x215c4 0x25a60 7 0x1000
291 2 0x60874 0x80a9874 0
294 raid:/nfs/raid/src/dist-18.56/src> dump -o xemacs
297 ***** PROGRAM EXECUTION HEADER *****
298 Type Offset Vaddr Paddr
299 Filesz Memsz Flags Align
308 0x3f2f9 0x3f2f9 5 0x1000
310 1 0x3f330 0x8088330 0
311 0x3e4d0 0x3e4d0 7 0x1000
313 2 0x60874 0x80a9874 0
319 /* Modified by wtien@urbana.mcd.mot.com of Motorola Inc.
321 * The above mechanism does not work if the unexeced ELF file is being
322 * re-layout by other applications (such as `strip'). All the applications
323 * that re-layout the internal of ELF will layout all sections in ascending
324 * order of their file offsets. After the re-layout, the data2 section will
325 * still be the LAST section in the section header vector, but its file offset
326 * is now being pushed far away down, and causes part of it not to be mapped
327 * in (ie. not covered by the load segment entry in PHDR vector), therefore
328 * causes the new binary to fail.
330 * The solution is to modify the unexec algorithm to insert the new data2
331 * section header right before the new bss section header, so their file
332 * offsets will be in the ascending order. Since some of the section's (all
333 * sections AFTER the bss section) indexes are now changed, we also need to
334 * modify some fields to make them point to the right sections. This is done
335 * by macro PATCH_INDEX. All the fields that need to be patched are:
337 * 1. ELF header e_shstrndx field.
338 * 2. section header sh_link and sh_info field.
339 * 3. symbol table entry st_shndx field.
341 * The above example now should look like:
343 **** SECTION HEADER TABLE ****
344 [No] Type Flags Addr Offset Size Name
345 Link Info Adralgn Entsize
347 [1] 1 2 0x80480d4 0xd4 0x13 .interp
350 [2] 5 2 0x80480e8 0xe8 0x388 .hash
353 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
356 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
359 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
362 [6] 1 6 0x8049348 0x1348 0x3 .init
365 [7] 1 6 0x804934c 0x134c 0x680 .plt
368 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
371 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
374 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
377 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
380 [12] 1 3 0x8088330 0x3f330 0x20afc .data
383 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
386 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
389 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
392 [16] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
395 [17] 8 3 0x80c6800 0x7d800 0 .bss
398 [18] 2 0 0 0x7d800 0x9b90 .symtab
401 [19] 3 0 0 0x87390 0x8526 .strtab
404 [20] 3 0 0 0x8f8b6 0x93 .shstrtab
407 [21] 1 0 0 0x8f949 0x68b7 .comment
412 #include <sys/types.h>
414 #include <sys/stat.h>
421 #include <syms.h> /* for HDRR declaration */
422 #include <sys/mman.h>
425 #define fatal(a, b, c) fprintf(stderr, a, b, c), exit(1)
427 extern void fatal(char *, ...);
430 /* Get the address of a particular section or program header entry,
431 * accounting for the size of the entries.
434 #define OLD_SECTION_H(n) \
435 (*(Elf32_Shdr *) ((byte *) old_section_h + old_file_h->e_shentsize * (n)))
436 #define NEW_SECTION_H(n) \
437 (*(Elf32_Shdr *) ((byte *) new_section_h + new_file_h->e_shentsize * (n)))
438 #define OLD_PROGRAM_H(n) \
439 (*(Elf32_Phdr *) ((byte *) old_program_h + old_file_h->e_phentsize * (n)))
440 #define NEW_PROGRAM_H(n) \
441 (*(Elf32_Phdr *) ((byte *) new_program_h + new_file_h->e_phentsize * (n)))
443 #define PATCH_INDEX(n) \
445 if ((n) >= old_bss_index) \
447 typedef unsigned char byte
;
449 /* Round X up to a multiple of Y. */
461 /* Return the index of the section named NAME.
462 SECTION_NAMES, FILE_NAME and FILE_H give information
463 about the file we are looking in.
465 If we don't find the section NAME, that is a fatal error
466 if NOERROR is 0; we return -1 if NOERROR is nonzero. */
469 find_section (name
, section_names
, file_name
, old_file_h
, old_section_h
, noerror
)
473 Elf32_Ehdr
*old_file_h
;
474 Elf32_Shdr
*old_section_h
;
479 for (idx
= 1; idx
< old_file_h
->e_shnum
; idx
++)
482 fprintf (stderr
, "Looking for %s - found %s\n", name
,
483 section_names
+ OLD_SECTION_H (idx
).sh_name
);
485 if (!strcmp (section_names
+ OLD_SECTION_H (idx
).sh_name
,
489 if (idx
== old_file_h
->e_shnum
)
494 fatal ("Can't find .bss in %s.\n", file_name
, 0);
500 /* ****************************************************************
505 * In ELF, this works by replacing the old .bss section with a new
506 * .data section, and inserting an empty .bss immediately afterwards.
510 unexec (new_name
, old_name
, data_start
, bss_start
, entry_address
)
511 char *new_name
, *old_name
;
512 unsigned data_start
, bss_start
, entry_address
;
514 extern unsigned int bss_end
;
515 int new_file
, old_file
, new_file_size
;
517 /* Pointers to the base of the image of the two files. */
518 caddr_t old_base
, new_base
;
520 /* Pointers to the file, program and section headers for the old and new
522 Elf32_Ehdr
*old_file_h
, *new_file_h
;
523 Elf32_Phdr
*old_program_h
, *new_program_h
;
524 Elf32_Shdr
*old_section_h
, *new_section_h
;
526 /* Point to the section name table in the old file. */
527 char *old_section_names
;
529 Elf32_Addr old_bss_addr
, new_bss_addr
;
530 Elf32_Word old_bss_size
, new_data2_size
;
531 Elf32_Off new_data2_offset
;
532 Elf32_Addr new_data2_addr
;
533 Elf32_Addr new_offsets_shift
;
535 int n
, nn
, old_bss_index
, old_data_index
, new_data2_index
;
536 int old_mdebug_index
;
537 struct stat stat_buf
;
539 /* Open the old file & map it into the address space. */
541 old_file
= open (old_name
, O_RDONLY
);
544 fatal ("Can't open %s for reading: errno %d\n", old_name
, errno
);
546 if (fstat (old_file
, &stat_buf
) == -1)
547 fatal ("Can't fstat(%s): errno %d\n", old_name
, errno
);
549 old_base
= mmap (0, stat_buf
.st_size
, PROT_READ
, MAP_SHARED
, old_file
, 0);
551 if (old_base
== (caddr_t
) -1)
552 fatal ("Can't mmap(%s): errno %d\n", old_name
, errno
);
555 fprintf (stderr
, "mmap(%s, %x) -> %x\n", old_name
, stat_buf
.st_size
,
559 /* Get pointers to headers & section names. */
561 old_file_h
= (Elf32_Ehdr
*) old_base
;
562 old_program_h
= (Elf32_Phdr
*) ((byte
*) old_base
+ old_file_h
->e_phoff
);
563 old_section_h
= (Elf32_Shdr
*) ((byte
*) old_base
+ old_file_h
->e_shoff
);
565 = (char *) old_base
+ OLD_SECTION_H (old_file_h
->e_shstrndx
).sh_offset
;
567 /* Find the mdebug section, if any. */
569 old_mdebug_index
= find_section (".mdebug", old_section_names
,
570 old_name
, old_file_h
, old_section_h
, 1);
572 /* Find the old .bss section. */
574 old_bss_index
= find_section (".bss", old_section_names
,
575 old_name
, old_file_h
, old_section_h
, 0);
577 /* Find the old .data section. Figure out parameters of
578 the new data2 and bss sections. */
580 old_data_index
= find_section (".data", old_section_names
,
581 old_name
, old_file_h
, old_section_h
, 0);
583 old_bss_addr
= OLD_SECTION_H (old_bss_index
).sh_addr
;
584 old_bss_size
= OLD_SECTION_H (old_bss_index
).sh_size
;
585 #if defined(emacs) || !defined(DEBUG)
586 bss_end
= (unsigned int) sbrk (0);
587 new_bss_addr
= (Elf32_Addr
) bss_end
;
589 new_bss_addr
= old_bss_addr
+ old_bss_size
+ 0x1234;
591 new_data2_addr
= old_bss_addr
;
592 new_data2_size
= new_bss_addr
- old_bss_addr
;
593 new_data2_offset
= OLD_SECTION_H (old_data_index
).sh_offset
+
594 (new_data2_addr
- OLD_SECTION_H (old_data_index
).sh_addr
);
595 new_offsets_shift
= new_bss_addr
-
596 ((old_bss_addr
& ~0xfff) + ((old_bss_addr
& 0xfff) ? 0x1000 : 0));
599 fprintf (stderr
, "old_bss_index %d\n", old_bss_index
);
600 fprintf (stderr
, "old_bss_addr %x\n", old_bss_addr
);
601 fprintf (stderr
, "old_bss_size %x\n", old_bss_size
);
602 fprintf (stderr
, "new_bss_addr %x\n", new_bss_addr
);
603 fprintf (stderr
, "new_data2_addr %x\n", new_data2_addr
);
604 fprintf (stderr
, "new_data2_size %x\n", new_data2_size
);
605 fprintf (stderr
, "new_data2_offset %x\n", new_data2_offset
);
606 fprintf (stderr
, "new_offsets_shift %x\n", new_offsets_shift
);
609 if ((unsigned) new_bss_addr
< (unsigned) old_bss_addr
+ old_bss_size
)
610 fatal (".bss shrank when undumping???\n", 0, 0);
612 /* Set the output file to the right size and mmap it. Set
613 pointers to various interesting objects. stat_buf still has
616 new_file
= open (new_name
, O_RDWR
| O_CREAT
, 0666);
618 fatal ("Can't creat (%s): errno %d\n", new_name
, errno
);
620 new_file_size
= stat_buf
.st_size
+ old_file_h
->e_shentsize
+ new_offsets_shift
;
622 if (ftruncate (new_file
, new_file_size
))
623 fatal ("Can't ftruncate (%s): errno %d\n", new_name
, errno
);
625 new_base
= mmap (0, new_file_size
, PROT_READ
| PROT_WRITE
, MAP_SHARED
,
628 if (new_base
== (caddr_t
) -1)
629 fatal ("Can't mmap (%s): errno %d\n", new_name
, errno
);
631 new_file_h
= (Elf32_Ehdr
*) new_base
;
632 new_program_h
= (Elf32_Phdr
*) ((byte
*) new_base
+ old_file_h
->e_phoff
);
634 = (Elf32_Shdr
*) ((byte
*) new_base
+ old_file_h
->e_shoff
635 + new_offsets_shift
);
637 /* Make our new file, program and section headers as copies of the
640 memcpy (new_file_h
, old_file_h
, old_file_h
->e_ehsize
);
641 memcpy (new_program_h
, old_program_h
,
642 old_file_h
->e_phnum
* old_file_h
->e_phentsize
);
644 /* Modify the e_shstrndx if necessary. */
645 PATCH_INDEX (new_file_h
->e_shstrndx
);
647 /* Fix up file header. We'll add one section. Section header is
650 new_file_h
->e_shoff
+= new_offsets_shift
;
651 new_file_h
->e_shnum
+= 1;
654 fprintf (stderr
, "Old section offset %x\n", old_file_h
->e_shoff
);
655 fprintf (stderr
, "Old section count %d\n", old_file_h
->e_shnum
);
656 fprintf (stderr
, "New section offset %x\n", new_file_h
->e_shoff
);
657 fprintf (stderr
, "New section count %d\n", new_file_h
->e_shnum
);
660 /* Fix up a new program header. Extend the writable data segment so
661 that the bss area is covered too. Find that segment by looking
662 for a segment that ends just before the .bss area. Make sure
663 that no segments are above the new .data2. Put a loop at the end
664 to adjust the offset and address of any segment that is above
665 data2, just in case we decide to allow this later. */
667 for (n
= new_file_h
->e_phnum
- 1; n
>= 0; n
--)
669 /* Compute maximum of all requirements for alignment of section. */
670 int alignment
= (NEW_PROGRAM_H (n
)).p_align
;
671 if ((OLD_SECTION_H (old_bss_index
)).sh_addralign
> alignment
)
672 alignment
= OLD_SECTION_H (old_bss_index
).sh_addralign
;
674 /* Supposedly this condition is okay for the SGI. */
676 if (NEW_PROGRAM_H (n
).p_vaddr
+ NEW_PROGRAM_H (n
).p_filesz
> old_bss_addr
)
677 fatal ("Program segment above .bss in %s\n", old_name
, 0);
680 if (NEW_PROGRAM_H (n
).p_type
== PT_LOAD
681 && (round_up ((NEW_PROGRAM_H (n
)).p_vaddr
682 + (NEW_PROGRAM_H (n
)).p_filesz
,
684 == round_up (old_bss_addr
, alignment
)))
688 fatal ("Couldn't find segment next to .bss in %s\n", old_name
, 0);
690 NEW_PROGRAM_H (n
).p_filesz
+= new_offsets_shift
;
691 NEW_PROGRAM_H (n
).p_memsz
= NEW_PROGRAM_H (n
).p_filesz
;
693 #if 1 /* Maybe allow section after data2 - does this ever happen? */
694 for (n
= new_file_h
->e_phnum
- 1; n
>= 0; n
--)
696 if (NEW_PROGRAM_H (n
).p_vaddr
697 && NEW_PROGRAM_H (n
).p_vaddr
>= new_data2_addr
)
698 NEW_PROGRAM_H (n
).p_vaddr
+= new_offsets_shift
- old_bss_size
;
700 if (NEW_PROGRAM_H (n
).p_offset
>= new_data2_offset
)
701 NEW_PROGRAM_H (n
).p_offset
+= new_offsets_shift
;
705 /* Fix up section headers based on new .data2 section. Any section
706 whose offset or virtual address is after the new .data2 section
707 gets its value adjusted. .bss size becomes zero and new address
708 is set. data2 section header gets added by copying the existing
709 .data header and modifying the offset, address and size. */
710 for (old_data_index
= 1; old_data_index
< old_file_h
->e_shnum
;
712 if (!strcmp (old_section_names
+ OLD_SECTION_H (old_data_index
).sh_name
,
715 if (old_data_index
== old_file_h
->e_shnum
)
716 fatal ("Can't find .data in %s.\n", old_name
, 0);
718 /* Walk through all section headers, insert the new data2 section right
719 before the new bss section. */
720 for (n
= 1, nn
= 1; n
< old_file_h
->e_shnum
; n
++, nn
++)
724 /* If it is bss section, insert the new data2 section before it. */
725 if (n
== old_bss_index
)
727 /* Steal the data section header for this data2 section. */
728 memcpy (&NEW_SECTION_H (nn
), &OLD_SECTION_H (old_data_index
),
729 new_file_h
->e_shentsize
);
731 NEW_SECTION_H (nn
).sh_addr
= new_data2_addr
;
732 NEW_SECTION_H (nn
).sh_offset
= new_data2_offset
;
733 NEW_SECTION_H (nn
).sh_size
= new_data2_size
;
734 /* Use the bss section's alignment. This will assure that the
735 new data2 section always be placed in the same spot as the old
736 bss section by any other application. */
737 NEW_SECTION_H (nn
).sh_addralign
= OLD_SECTION_H (n
).sh_addralign
;
739 /* Now copy over what we have in the memory now. */
740 memcpy (NEW_SECTION_H (nn
).sh_offset
+ new_base
,
741 (caddr_t
) OLD_SECTION_H (n
).sh_addr
,
744 memcpy (&NEW_SECTION_H (nn
), &OLD_SECTION_H (n
),
745 old_file_h
->e_shentsize
);
747 /* The new bss section's size is zero, and its file offset and virtual
748 address should be off by NEW_OFFSETS_SHIFT. */
749 NEW_SECTION_H (nn
).sh_offset
+= new_offsets_shift
;
750 NEW_SECTION_H (nn
).sh_addr
= new_bss_addr
;
751 /* Let the new bss section address alignment be the same as the
752 section address alignment followed the old bss section, so
753 this section will be placed in exactly the same place. */
754 NEW_SECTION_H (nn
).sh_addralign
= OLD_SECTION_H (nn
).sh_addralign
;
755 NEW_SECTION_H (nn
).sh_size
= 0;
758 memcpy (&NEW_SECTION_H (nn
), &OLD_SECTION_H (n
),
759 old_file_h
->e_shentsize
);
761 /* Any section that was original placed AFTER the bss
762 section must now be adjusted by NEW_OFFSETS_SHIFT. */
764 if (NEW_SECTION_H (nn
).sh_offset
>= new_data2_offset
)
765 NEW_SECTION_H (nn
).sh_offset
+= new_offsets_shift
;
767 /* If any section hdr refers to the section after the new .data
768 section, make it refer to next one because we have inserted
769 a new section in between. */
771 PATCH_INDEX (NEW_SECTION_H (nn
).sh_link
);
772 /* For symbol tables, info is a symbol table index,
773 so don't change it. */
774 if (NEW_SECTION_H (nn
).sh_type
!= SHT_SYMTAB
775 && NEW_SECTION_H (nn
).sh_type
!= SHT_DYNSYM
)
776 PATCH_INDEX (NEW_SECTION_H (nn
).sh_info
);
778 /* Now, start to copy the content of sections. */
779 if (NEW_SECTION_H (nn
).sh_type
== SHT_NULL
780 || NEW_SECTION_H (nn
).sh_type
== SHT_NOBITS
)
783 /* Write out the sections. .data and .data1 (and data2, called
784 ".data" in the strings table) get copied from the current process
785 instead of the old file. */
786 if (!strcmp (old_section_names
+ NEW_SECTION_H (n
).sh_name
, ".data")
787 || !strcmp (old_section_names
+ NEW_SECTION_H (n
).sh_name
, ".data1")
788 || !strcmp (old_section_names
+ NEW_SECTION_H (n
).sh_name
, ".got"))
789 src
= (caddr_t
) OLD_SECTION_H (n
).sh_addr
;
791 src
= old_base
+ OLD_SECTION_H (n
).sh_offset
;
793 memcpy (NEW_SECTION_H (nn
).sh_offset
+ new_base
, src
,
794 NEW_SECTION_H (nn
).sh_size
);
796 /* Adjust the HDRR offsets in .mdebug and copy the
797 line data if it's in its usual 'hole' in the object.
798 Makes the new file debuggable with dbx.
799 patches up two problems: the absolute file offsets
800 in the HDRR record of .mdebug (see /usr/include/syms.h), and
801 the ld bug that gets the line table in a hole in the
802 elf file rather than in the .mdebug section proper.
803 David Anderson. davea@sgi.com Jan 16,1994. */
804 if (n
== old_mdebug_index
)
806 #define MDEBUGADJUST(__ct,__fileaddr) \
807 if (n_phdrr->__ct > 0) \
809 n_phdrr->__fileaddr += movement; \
812 HDRR
* o_phdrr
= (HDRR
*)((byte
*)old_base
+ OLD_SECTION_H (n
).sh_offset
);
813 HDRR
* n_phdrr
= (HDRR
*)((byte
*)new_base
+ NEW_SECTION_H (nn
).sh_offset
);
814 unsigned movement
= new_offsets_shift
;
816 MDEBUGADJUST (idnMax
, cbDnOffset
);
817 MDEBUGADJUST (ipdMax
, cbPdOffset
);
818 MDEBUGADJUST (isymMax
, cbSymOffset
);
819 MDEBUGADJUST (ioptMax
, cbOptOffset
);
820 MDEBUGADJUST (iauxMax
, cbAuxOffset
);
821 MDEBUGADJUST (issMax
, cbSsOffset
);
822 MDEBUGADJUST (issExtMax
, cbSsExtOffset
);
823 MDEBUGADJUST (ifdMax
, cbFdOffset
);
824 MDEBUGADJUST (crfd
, cbRfdOffset
);
825 MDEBUGADJUST (iextMax
, cbExtOffset
);
826 /* The Line Section, being possible off in a hole of the object,
827 requires special handling. */
828 if (n_phdrr
->cbLine
> 0)
830 if (o_phdrr
->cbLineOffset
> (OLD_SECTION_H (n
).sh_offset
831 + OLD_SECTION_H (n
).sh_size
))
833 /* line data is in a hole in elf. do special copy and adjust
836 n_phdrr
->cbLineOffset
+= movement
;
838 memcpy (n_phdrr
->cbLineOffset
+ new_base
,
839 o_phdrr
->cbLineOffset
+ old_base
, n_phdrr
->cbLine
);
843 /* somehow line data is in .mdebug as it is supposed to be. */
844 MDEBUGADJUST (cbLine
, cbLineOffset
);
849 /* If it is the symbol table, its st_shndx field needs to be patched. */
850 if (NEW_SECTION_H (nn
).sh_type
== SHT_SYMTAB
851 || NEW_SECTION_H (nn
).sh_type
== SHT_DYNSYM
)
853 Elf32_Shdr
*spt
= &NEW_SECTION_H (nn
);
854 unsigned int num
= spt
->sh_size
/ spt
->sh_entsize
;
855 Elf32_Sym
* sym
= (Elf32_Sym
*) (NEW_SECTION_H (nn
).sh_offset
859 if (sym
->st_shndx
== SHN_UNDEF
860 || sym
->st_shndx
== SHN_ABS
861 || sym
->st_shndx
== SHN_COMMON
)
864 PATCH_INDEX (sym
->st_shndx
);
869 /* Close the files and make the new file executable. */
871 if (close (old_file
))
872 fatal ("Can't close (%s): errno %d\n", old_name
, errno
);
874 if (close (new_file
))
875 fatal ("Can't close (%s): errno %d\n", new_name
, errno
);
877 if (stat (new_name
, &stat_buf
) == -1)
878 fatal ("Can't stat (%s): errno %d\n", new_name
, errno
);
882 stat_buf
.st_mode
|= 0111 & ~n
;
883 if (chmod (new_name
, stat_buf
.st_mode
) == -1)
884 fatal ("Can't chmod (%s): errno %d\n", new_name
, errno
);