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[emacs.git] / src / unexelf.c
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1 /* Copyright (C) 1985, 1986, 1987, 1988, 1990, 1992, 1999, 2000
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 2, or (at your option)
9 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; see the file COPYING. If not, write to
18 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA.
21 In other words, you are welcome to use, share and improve this program.
22 You are forbidden to forbid anyone else to use, share and improve
23 what you give them. Help stamp out software-hoarding! */
27 * unexec.c - Convert a running program into an a.out file.
29 * Author: Spencer W. Thomas
30 * Computer Science Dept.
31 * University of Utah
32 * Date: Tue Mar 2 1982
33 * Modified heavily since then.
35 * Synopsis:
36 * unexec (new_name, old_name, data_start, bss_start, entry_address)
37 * char *new_name, *old_name;
38 * unsigned data_start, bss_start, entry_address;
40 * Takes a snapshot of the program and makes an a.out format file in the
41 * file named by the string argument new_name.
42 * If old_name is non-NULL, the symbol table will be taken from the given file.
43 * On some machines, an existing old_name file is required.
45 * The boundaries within the a.out file may be adjusted with the data_start
46 * and bss_start arguments. Either or both may be given as 0 for defaults.
48 * Data_start gives the boundary between the text segment and the data
49 * segment of the program. The text segment can contain shared, read-only
50 * program code and literal data, while the data segment is always unshared
51 * and unprotected. Data_start gives the lowest unprotected address.
52 * The value you specify may be rounded down to a suitable boundary
53 * as required by the machine you are using.
55 * Bss_start indicates how much of the data segment is to be saved in the
56 * a.out file and restored when the program is executed. It gives the lowest
57 * unsaved address, and is rounded up to a page boundary. The default when 0
58 * is given assumes that the entire data segment is to be stored, including
59 * the previous data and bss as well as any additional storage allocated with
60 * break (2).
62 * The new file is set up to start at entry_address.
66 /* Even more heavily modified by james@bigtex.cactus.org of Dell Computer Co.
67 * ELF support added.
69 * Basic theory: the data space of the running process needs to be
70 * dumped to the output file. Normally we would just enlarge the size
71 * of .data, scooting everything down. But we can't do that in ELF,
72 * because there is often something between the .data space and the
73 * .bss space.
75 * In the temacs dump below, notice that the Global Offset Table
76 * (.got) and the Dynamic link data (.dynamic) come between .data1 and
77 * .bss. It does not work to overlap .data with these fields.
79 * The solution is to create a new .data segment. This segment is
80 * filled with data from the current process. Since the contents of
81 * various sections refer to sections by index, the new .data segment
82 * is made the last in the table to avoid changing any existing index.
84 * This is an example of how the section headers are changed. "Addr"
85 * is a process virtual address. "Offset" is a file offset.
87 raid:/nfs/raid/src/dist-18.56/src> dump -h temacs
89 temacs:
91 **** SECTION HEADER TABLE ****
92 [No] Type Flags Addr Offset Size Name
93 Link Info Adralgn Entsize
95 [1] 1 2 0x80480d4 0xd4 0x13 .interp
96 0 0 0x1 0
98 [2] 5 2 0x80480e8 0xe8 0x388 .hash
99 3 0 0x4 0x4
101 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
102 4 1 0x4 0x10
104 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
105 0 0 0x1 0
107 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
108 3 7 0x4 0x8
110 [6] 1 6 0x8049348 0x1348 0x3 .init
111 0 0 0x4 0
113 [7] 1 6 0x804934c 0x134c 0x680 .plt
114 0 0 0x4 0x4
116 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
117 0 0 0x4 0
119 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
120 0 0 0x4 0
122 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
123 0 0 0x4 0
125 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
126 0 0 0x4 0
128 [12] 1 3 0x8088330 0x3f330 0x20afc .data
129 0 0 0x4 0
131 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
132 0 0 0x4 0
134 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
135 0 0 0x4 0x4
137 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
138 4 0 0x4 0x8
140 [16] 8 3 0x80a98f4 0x608f4 0x449c .bss
141 0 0 0x4 0
143 [17] 2 0 0 0x608f4 0x9b90 .symtab
144 18 371 0x4 0x10
146 [18] 3 0 0 0x6a484 0x8526 .strtab
147 0 0 0x1 0
149 [19] 3 0 0 0x729aa 0x93 .shstrtab
150 0 0 0x1 0
152 [20] 1 0 0 0x72a3d 0x68b7 .comment
153 0 0 0x1 0
155 raid:/nfs/raid/src/dist-18.56/src> dump -h xemacs
157 xemacs:
159 **** SECTION HEADER TABLE ****
160 [No] Type Flags Addr Offset Size Name
161 Link Info Adralgn Entsize
163 [1] 1 2 0x80480d4 0xd4 0x13 .interp
164 0 0 0x1 0
166 [2] 5 2 0x80480e8 0xe8 0x388 .hash
167 3 0 0x4 0x4
169 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
170 4 1 0x4 0x10
172 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
173 0 0 0x1 0
175 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
176 3 7 0x4 0x8
178 [6] 1 6 0x8049348 0x1348 0x3 .init
179 0 0 0x4 0
181 [7] 1 6 0x804934c 0x134c 0x680 .plt
182 0 0 0x4 0x4
184 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
185 0 0 0x4 0
187 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
188 0 0 0x4 0
190 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
191 0 0 0x4 0
193 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
194 0 0 0x4 0
196 [12] 1 3 0x8088330 0x3f330 0x20afc .data
197 0 0 0x4 0
199 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
200 0 0 0x4 0
202 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
203 0 0 0x4 0x4
205 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
206 4 0 0x4 0x8
208 [16] 8 3 0x80c6800 0x7d800 0 .bss
209 0 0 0x4 0
211 [17] 2 0 0 0x7d800 0x9b90 .symtab
212 18 371 0x4 0x10
214 [18] 3 0 0 0x87390 0x8526 .strtab
215 0 0 0x1 0
217 [19] 3 0 0 0x8f8b6 0x93 .shstrtab
218 0 0 0x1 0
220 [20] 1 0 0 0x8f949 0x68b7 .comment
221 0 0 0x1 0
223 [21] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
224 0 0 0x4 0
226 * This is an example of how the file header is changed. "Shoff" is
227 * the section header offset within the file. Since that table is
228 * after the new .data section, it is moved. "Shnum" is the number of
229 * sections, which we increment.
231 * "Phoff" is the file offset to the program header. "Phentsize" and
232 * "Shentsz" are the program and section header entries sizes respectively.
233 * These can be larger than the apparent struct sizes.
235 raid:/nfs/raid/src/dist-18.56/src> dump -f temacs
237 temacs:
239 **** ELF HEADER ****
240 Class Data Type Machine Version
241 Entry Phoff Shoff Flags Ehsize
242 Phentsize Phnum Shentsz Shnum Shstrndx
244 1 1 2 3 1
245 0x80499cc 0x34 0x792f4 0 0x34
246 0x20 5 0x28 21 19
248 raid:/nfs/raid/src/dist-18.56/src> dump -f xemacs
250 xemacs:
252 **** ELF HEADER ****
253 Class Data Type Machine Version
254 Entry Phoff Shoff Flags Ehsize
255 Phentsize Phnum Shentsz Shnum Shstrndx
257 1 1 2 3 1
258 0x80499cc 0x34 0x96200 0 0x34
259 0x20 5 0x28 22 19
261 * These are the program headers. "Offset" is the file offset to the
262 * segment. "Vaddr" is the memory load address. "Filesz" is the
263 * segment size as it appears in the file, and "Memsz" is the size in
264 * memory. Below, the third segment is the code and the fourth is the
265 * data: the difference between Filesz and Memsz is .bss
267 raid:/nfs/raid/src/dist-18.56/src> dump -o temacs
269 temacs:
270 ***** PROGRAM EXECUTION HEADER *****
271 Type Offset Vaddr Paddr
272 Filesz Memsz Flags Align
274 6 0x34 0x8048034 0
275 0xa0 0xa0 5 0
277 3 0xd4 0 0
278 0x13 0 4 0
280 1 0x34 0x8048034 0
281 0x3f2f9 0x3f2f9 5 0x1000
283 1 0x3f330 0x8088330 0
284 0x215c4 0x25a60 7 0x1000
286 2 0x60874 0x80a9874 0
287 0x80 0 7 0
289 raid:/nfs/raid/src/dist-18.56/src> dump -o xemacs
291 xemacs:
292 ***** PROGRAM EXECUTION HEADER *****
293 Type Offset Vaddr Paddr
294 Filesz Memsz Flags Align
296 6 0x34 0x8048034 0
297 0xa0 0xa0 5 0
299 3 0xd4 0 0
300 0x13 0 4 0
302 1 0x34 0x8048034 0
303 0x3f2f9 0x3f2f9 5 0x1000
305 1 0x3f330 0x8088330 0
306 0x3e4d0 0x3e4d0 7 0x1000
308 2 0x60874 0x80a9874 0
309 0x80 0 7 0
314 /* Modified by wtien@urbana.mcd.mot.com of Motorola Inc.
316 * The above mechanism does not work if the unexeced ELF file is being
317 * re-layout by other applications (such as `strip'). All the applications
318 * that re-layout the internal of ELF will layout all sections in ascending
319 * order of their file offsets. After the re-layout, the data2 section will
320 * still be the LAST section in the section header vector, but its file offset
321 * is now being pushed far away down, and causes part of it not to be mapped
322 * in (ie. not covered by the load segment entry in PHDR vector), therefore
323 * causes the new binary to fail.
325 * The solution is to modify the unexec algorithm to insert the new data2
326 * section header right before the new bss section header, so their file
327 * offsets will be in the ascending order. Since some of the section's (all
328 * sections AFTER the bss section) indexes are now changed, we also need to
329 * modify some fields to make them point to the right sections. This is done
330 * by macro PATCH_INDEX. All the fields that need to be patched are:
332 * 1. ELF header e_shstrndx field.
333 * 2. section header sh_link and sh_info field.
334 * 3. symbol table entry st_shndx field.
336 * The above example now should look like:
338 **** SECTION HEADER TABLE ****
339 [No] Type Flags Addr Offset Size Name
340 Link Info Adralgn Entsize
342 [1] 1 2 0x80480d4 0xd4 0x13 .interp
343 0 0 0x1 0
345 [2] 5 2 0x80480e8 0xe8 0x388 .hash
346 3 0 0x4 0x4
348 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
349 4 1 0x4 0x10
351 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
352 0 0 0x1 0
354 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
355 3 7 0x4 0x8
357 [6] 1 6 0x8049348 0x1348 0x3 .init
358 0 0 0x4 0
360 [7] 1 6 0x804934c 0x134c 0x680 .plt
361 0 0 0x4 0x4
363 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
364 0 0 0x4 0
366 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
367 0 0 0x4 0
369 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
370 0 0 0x4 0
372 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
373 0 0 0x4 0
375 [12] 1 3 0x8088330 0x3f330 0x20afc .data
376 0 0 0x4 0
378 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
379 0 0 0x4 0
381 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
382 0 0 0x4 0x4
384 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
385 4 0 0x4 0x8
387 [16] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
388 0 0 0x4 0
390 [17] 8 3 0x80c6800 0x7d800 0 .bss
391 0 0 0x4 0
393 [18] 2 0 0 0x7d800 0x9b90 .symtab
394 19 371 0x4 0x10
396 [19] 3 0 0 0x87390 0x8526 .strtab
397 0 0 0x1 0
399 [20] 3 0 0 0x8f8b6 0x93 .shstrtab
400 0 0 0x1 0
402 [21] 1 0 0 0x8f949 0x68b7 .comment
403 0 0 0x1 0
407 #ifndef emacs
408 #define fatal(a, b, c) fprintf (stderr, a, b, c), exit (1)
409 #include <string.h>
410 #else
411 #include <config.h>
412 extern void fatal (char *, ...);
413 #endif
415 #include <sys/types.h>
416 #include <stdio.h>
417 #include <sys/stat.h>
418 #include <memory.h>
419 #include <errno.h>
420 #include <unistd.h>
421 #include <fcntl.h>
422 #if !defined (__NetBSD__) && !defined (__OpenBSD__)
423 #include <elf.h>
424 #endif
425 #include <sys/mman.h>
426 #if defined (__sony_news) && defined (_SYSTYPE_SYSV)
427 #include <sys/elf_mips.h>
428 #include <sym.h>
429 #endif /* __sony_news && _SYSTYPE_SYSV */
430 #if __sgi
431 #include <syms.h> /* for HDRR declaration */
432 #endif /* __sgi */
434 #if defined (__alpha__) && !defined (__NetBSD__) && !defined (__OpenBSD__)
435 /* Declare COFF debugging symbol table. This used to be in
436 /usr/include/sym.h, but this file is no longer included in Red Hat
437 5.0 and presumably in any other glibc 2.x based distribution. */
438 typedef struct {
439 short magic;
440 short vstamp;
441 int ilineMax;
442 int idnMax;
443 int ipdMax;
444 int isymMax;
445 int ioptMax;
446 int iauxMax;
447 int issMax;
448 int issExtMax;
449 int ifdMax;
450 int crfd;
451 int iextMax;
452 long cbLine;
453 long cbLineOffset;
454 long cbDnOffset;
455 long cbPdOffset;
456 long cbSymOffset;
457 long cbOptOffset;
458 long cbAuxOffset;
459 long cbSsOffset;
460 long cbSsExtOffset;
461 long cbFdOffset;
462 long cbRfdOffset;
463 long cbExtOffset;
464 } HDRR, *pHDRR;
465 #define cbHDRR sizeof(HDRR)
466 #define hdrNil ((pHDRR)0)
467 #endif
469 #ifdef __NetBSD__
471 * NetBSD does not have normal-looking user-land ELF support.
473 # if defined __alpha__ || defined __sparc_v9__
474 # define ELFSIZE 64
475 # else
476 # define ELFSIZE 32
477 # endif
478 # include <sys/exec_elf.h>
480 # ifndef PT_LOAD
481 # define PT_LOAD Elf_pt_load
482 # if 0 /* was in pkgsrc patches for 20.7 */
483 # define SHT_PROGBITS Elf_sht_progbits
484 # endif
485 # define SHT_SYMTAB Elf_sht_symtab
486 # define SHT_DYNSYM Elf_sht_dynsym
487 # define SHT_NULL Elf_sht_null
488 # define SHT_NOBITS Elf_sht_nobits
489 # define SHT_REL Elf_sht_rel
490 # define SHT_RELA Elf_sht_rela
492 # define SHN_UNDEF Elf_eshn_undefined
493 # define SHN_ABS Elf_eshn_absolute
494 # define SHN_COMMON Elf_eshn_common
495 # endif /* !PT_LOAD */
497 # ifdef __alpha__
498 # include <sys/exec_ecoff.h>
499 # define HDRR struct ecoff_symhdr
500 # define pHDRR HDRR *
501 # endif /* __alpha__ */
503 #ifdef __mips__ /* was in pkgsrc patches for 20.7 */
504 # define SHT_MIPS_DEBUG DT_MIPS_FLAGS
505 # define HDRR struct Elf_Shdr
506 #endif /* __mips__ */
507 #endif /* __NetBSD__ */
509 #ifdef __OpenBSD__
510 # include <sys/exec_elf.h>
511 #endif
513 #if __GNU_LIBRARY__ - 0 >= 6
514 # include <link.h> /* get ElfW etc */
515 #endif
517 #ifndef ElfW
518 # ifdef __STDC__
519 # define ElfBitsW(bits, type) Elf##bits##_##type
520 # else
521 # define ElfBitsW(bits, type) Elf/**/bits/**/_/**/type
522 # endif
523 # ifdef _LP64
524 # define ELFSIZE 64
525 # else
526 # define ELFSIZE 32
527 # endif
528 /* This macro expands `bits' before invoking ElfBitsW. */
529 # define ElfExpandBitsW(bits, type) ElfBitsW (bits, type)
530 # define ElfW(type) ElfExpandBitsW (ELFSIZE, type)
531 #endif
533 #ifndef ELF_BSS_SECTION_NAME
534 #define ELF_BSS_SECTION_NAME ".bss"
535 #endif
537 /* Get the address of a particular section or program header entry,
538 * accounting for the size of the entries.
541 On PPC Reference Platform running Solaris 2.5.1
542 the plt section is also of type NOBI like the bss section.
543 (not really stored) and therefore sections after the bss
544 section start at the plt offset. The plt section is always
545 the one just before the bss section.
546 Thus, we modify the test from
547 if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset)
549 if (NEW_SECTION_H (nn).sh_offset >=
550 OLD_SECTION_H (old_bss_index-1).sh_offset)
551 This is just a hack. We should put the new data section
552 before the .plt section.
553 And we should not have this routine at all but use
554 the libelf library to read the old file and create the new
555 file.
556 The changed code is minimal and depends on prep set in m/prep.h
557 Erik Deumens
558 Quantum Theory Project
559 University of Florida
560 deumens@qtp.ufl.edu
561 Apr 23, 1996
564 #define OLD_SECTION_H(n) \
565 (*(ElfW(Shdr) *) ((byte *) old_section_h + old_file_h->e_shentsize * (n)))
566 #define NEW_SECTION_H(n) \
567 (*(ElfW(Shdr) *) ((byte *) new_section_h + new_file_h->e_shentsize * (n)))
568 #define OLD_PROGRAM_H(n) \
569 (*(ElfW(Phdr) *) ((byte *) old_program_h + old_file_h->e_phentsize * (n)))
570 #define NEW_PROGRAM_H(n) \
571 (*(ElfW(Phdr) *) ((byte *) new_program_h + new_file_h->e_phentsize * (n)))
573 #define PATCH_INDEX(n) \
574 do { \
575 if ((int) (n) >= old_bss_index) \
576 (n)++; } while (0)
577 typedef unsigned char byte;
579 /* Round X up to a multiple of Y. */
581 static ElfW(Addr)
582 round_up (x, y)
583 ElfW(Addr) x, y;
585 int rem = x % y;
586 if (rem == 0)
587 return x;
588 return x - rem + y;
591 /* Return the index of the section named NAME.
592 SECTION_NAMES, FILE_NAME and FILE_H give information
593 about the file we are looking in.
595 If we don't find the section NAME, that is a fatal error
596 if NOERROR is 0; we return -1 if NOERROR is nonzero. */
598 static int
599 find_section (name, section_names, file_name, old_file_h, old_section_h, noerror)
600 char *name;
601 char *section_names;
602 char *file_name;
603 ElfW(Ehdr) *old_file_h;
604 ElfW(Shdr) *old_section_h;
605 int noerror;
607 int idx;
609 for (idx = 1; idx < old_file_h->e_shnum; idx++)
611 #ifdef DEBUG
612 fprintf (stderr, "Looking for %s - found %s\n", name,
613 section_names + OLD_SECTION_H (idx).sh_name);
614 #endif
615 if (!strcmp (section_names + OLD_SECTION_H (idx).sh_name,
616 name))
617 break;
619 if (idx == old_file_h->e_shnum)
621 if (noerror)
622 return -1;
623 else
624 fatal ("Can't find %s in %s.\n", name, file_name);
627 return idx;
630 /* ****************************************************************
631 * unexec
633 * driving logic.
635 * In ELF, this works by replacing the old .bss section with a new
636 * .data section, and inserting an empty .bss immediately afterwards.
639 void
640 unexec (new_name, old_name, data_start, bss_start, entry_address)
641 char *new_name, *old_name;
642 unsigned data_start, bss_start, entry_address;
644 int new_file, old_file, new_file_size;
646 /* Pointers to the base of the image of the two files. */
647 caddr_t old_base, new_base;
649 /* Pointers to the file, program and section headers for the old and new
650 * files.
652 ElfW(Ehdr) *old_file_h, *new_file_h;
653 ElfW(Phdr) *old_program_h, *new_program_h;
654 ElfW(Shdr) *old_section_h, *new_section_h;
656 /* Point to the section name table in the old file */
657 char *old_section_names;
659 ElfW(Addr) old_bss_addr, new_bss_addr;
660 ElfW(Word) old_bss_size, new_data2_size;
661 ElfW(Off) new_data2_offset;
662 ElfW(Addr) new_data2_addr;
664 int n, nn;
665 int old_bss_index, old_sbss_index;
666 int old_data_index, new_data2_index;
667 int old_mdebug_index;
668 struct stat stat_buf;
670 /* Open the old file & map it into the address space. */
672 old_file = open (old_name, O_RDONLY);
674 if (old_file < 0)
675 fatal ("Can't open %s for reading: errno %d\n", old_name, errno);
677 if (fstat (old_file, &stat_buf) == -1)
678 fatal ("Can't fstat (%s): errno %d\n", old_name, errno);
680 old_base = mmap ((caddr_t) 0, stat_buf.st_size, PROT_READ, MAP_SHARED,
681 old_file, 0);
683 if (old_base == (caddr_t) -1)
684 fatal ("Can't mmap (%s): errno %d\n", old_name, errno);
686 #ifdef DEBUG
687 fprintf (stderr, "mmap (%s, %x) -> %x\n", old_name, stat_buf.st_size,
688 old_base);
689 #endif
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 old_mdebug_index = find_section (".mdebug", old_section_names,
702 old_name, old_file_h, old_section_h, 1);
704 /* Find the old .bss section. Figure out parameters of the new
705 * data2 and bss sections.
708 old_bss_index = find_section (".bss", old_section_names,
709 old_name, old_file_h, old_section_h, 0);
711 old_sbss_index = find_section (".sbss", old_section_names,
712 old_name, old_file_h, old_section_h, 1);
713 if (old_sbss_index != -1)
714 if (OLD_SECTION_H (old_sbss_index).sh_type == SHT_PROGBITS)
715 old_sbss_index = -1;
717 if (old_sbss_index == -1)
719 old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr;
720 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size;
721 new_data2_index = old_bss_index;
723 else
725 old_bss_addr = OLD_SECTION_H (old_sbss_index).sh_addr;
726 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size
727 + OLD_SECTION_H (old_sbss_index).sh_size;
728 new_data2_index = old_sbss_index;
731 /* Find the old .data section. Figure out parameters of
732 the new data2 and bss sections. */
734 old_data_index = find_section (".data", old_section_names,
735 old_name, old_file_h, old_section_h, 0);
737 #if defined (emacs) || !defined (DEBUG)
738 new_bss_addr = (ElfW(Addr)) sbrk (0);
739 #else
740 new_bss_addr = old_bss_addr + old_bss_size + 0x1234;
741 #endif
742 new_data2_addr = old_bss_addr;
743 new_data2_size = new_bss_addr - old_bss_addr;
744 new_data2_offset = OLD_SECTION_H (old_data_index).sh_offset +
745 (new_data2_addr - OLD_SECTION_H (old_data_index).sh_addr);
747 #ifdef DEBUG
748 fprintf (stderr, "old_bss_index %d\n", old_bss_index);
749 fprintf (stderr, "old_bss_addr %x\n", old_bss_addr);
750 fprintf (stderr, "old_bss_size %x\n", old_bss_size);
751 fprintf (stderr, "new_bss_addr %x\n", new_bss_addr);
752 fprintf (stderr, "new_data2_addr %x\n", new_data2_addr);
753 fprintf (stderr, "new_data2_size %x\n", new_data2_size);
754 fprintf (stderr, "new_data2_offset %x\n", new_data2_offset);
755 #endif
757 if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size)
758 fatal (".bss shrank when undumping???\n", 0, 0);
760 /* Set the output file to the right size and mmap it. Set
761 * pointers to various interesting objects. stat_buf still has
762 * old_file data.
765 new_file = open (new_name, O_RDWR | O_CREAT, 0666);
766 if (new_file < 0)
767 fatal ("Can't creat (%s): errno %d\n", new_name, errno);
769 new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_data2_size;
771 if (ftruncate (new_file, new_file_size))
772 fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
774 #ifdef UNEXEC_USE_MAP_PRIVATE
775 new_base = mmap ((caddr_t) 0, new_file_size, PROT_READ | PROT_WRITE,
776 MAP_PRIVATE, new_file, 0);
777 #else
778 new_base = mmap ((caddr_t) 0, new_file_size, PROT_READ | PROT_WRITE,
779 MAP_SHARED, new_file, 0);
780 #endif
782 if (new_base == (caddr_t) -1)
783 fatal ("Can't mmap (%s): errno %d\n", new_name, errno);
785 new_file_h = (ElfW(Ehdr) *) new_base;
786 new_program_h = (ElfW(Phdr) *) ((byte *) new_base + old_file_h->e_phoff);
787 new_section_h = (ElfW(Shdr) *)
788 ((byte *) new_base + old_file_h->e_shoff + new_data2_size);
790 /* Make our new file, program and section headers as copies of the
791 * originals.
794 memcpy (new_file_h, old_file_h, old_file_h->e_ehsize);
795 memcpy (new_program_h, old_program_h,
796 old_file_h->e_phnum * old_file_h->e_phentsize);
798 /* Modify the e_shstrndx if necessary. */
799 PATCH_INDEX (new_file_h->e_shstrndx);
801 /* Fix up file header. We'll add one section. Section header is
802 * further away now.
805 new_file_h->e_shoff += new_data2_size;
806 new_file_h->e_shnum += 1;
808 #ifdef DEBUG
809 fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff);
810 fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum);
811 fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff);
812 fprintf (stderr, "New section count %d\n", new_file_h->e_shnum);
813 #endif
815 /* Fix up a new program header. Extend the writable data segment so
816 * that the bss area is covered too. Find that segment by looking
817 * for a segment that ends just before the .bss area. Make sure
818 * that no segments are above the new .data2. Put a loop at the end
819 * to adjust the offset and address of any segment that is above
820 * data2, just in case we decide to allow this later.
823 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
825 /* Compute maximum of all requirements for alignment of section. */
826 ElfW(Word) alignment = (NEW_PROGRAM_H (n)).p_align;
827 if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment)
828 alignment = OLD_SECTION_H (old_bss_index).sh_addralign;
830 #ifdef __sgi
831 /* According to r02kar@x4u2.desy.de (Karsten Kuenne)
832 and oliva@gnu.org (Alexandre Oliva), on IRIX 5.2, we
833 always get "Program segment above .bss" when dumping
834 when the executable doesn't have an sbss section. */
835 if (old_sbss_index != -1)
836 #endif /* __sgi */
837 if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz
838 > (old_sbss_index == -1
839 ? old_bss_addr
840 : round_up (old_bss_addr, alignment)))
841 fatal ("Program segment above .bss in %s\n", old_name, 0);
843 if (NEW_PROGRAM_H (n).p_type == PT_LOAD
844 && (round_up ((NEW_PROGRAM_H (n)).p_vaddr
845 + (NEW_PROGRAM_H (n)).p_filesz,
846 alignment)
847 == round_up (old_bss_addr, alignment)))
848 break;
850 if (n < 0)
851 fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0);
853 /* Make sure that the size includes any padding before the old .bss
854 section. */
855 NEW_PROGRAM_H (n).p_filesz = new_bss_addr - NEW_PROGRAM_H (n).p_vaddr;
856 NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz;
858 #if 0 /* Maybe allow section after data2 - does this ever happen? */
859 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
861 if (NEW_PROGRAM_H (n).p_vaddr
862 && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr)
863 NEW_PROGRAM_H (n).p_vaddr += new_data2_size - old_bss_size;
865 if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset)
866 NEW_PROGRAM_H (n).p_offset += new_data2_size;
868 #endif
870 /* Fix up section headers based on new .data2 section. Any section
871 * whose offset or virtual address is after the new .data2 section
872 * gets its value adjusted. .bss size becomes zero and new address
873 * is set. data2 section header gets added by copying the existing
874 * .data header and modifying the offset, address and size.
876 for (old_data_index = 1; old_data_index < (int) old_file_h->e_shnum;
877 old_data_index++)
878 if (!strcmp (old_section_names + OLD_SECTION_H (old_data_index).sh_name,
879 ".data"))
880 break;
881 if (old_data_index == old_file_h->e_shnum)
882 fatal ("Can't find .data in %s.\n", old_name, 0);
884 /* Walk through all section headers, insert the new data2 section right
885 before the new bss section. */
886 for (n = 1, nn = 1; n < (int) old_file_h->e_shnum; n++, nn++)
888 caddr_t src;
889 /* If it is (s)bss section, insert the new data2 section before it. */
890 /* new_data2_index is the index of either old_sbss or old_bss, that was
891 chosen as a section for new_data2. */
892 if (n == new_data2_index)
894 /* Steal the data section header for this data2 section. */
895 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index),
896 new_file_h->e_shentsize);
898 NEW_SECTION_H (nn).sh_addr = new_data2_addr;
899 NEW_SECTION_H (nn).sh_offset = new_data2_offset;
900 NEW_SECTION_H (nn).sh_size = new_data2_size;
901 /* Use the bss section's alignment. This will assure that the
902 new data2 section always be placed in the same spot as the old
903 bss section by any other application. */
904 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign;
906 /* Now copy over what we have in the memory now. */
907 memcpy (NEW_SECTION_H (nn).sh_offset + new_base,
908 (caddr_t) OLD_SECTION_H (n).sh_addr,
909 new_data2_size);
910 nn++;
913 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
914 old_file_h->e_shentsize);
916 if (n == old_bss_index
917 /* The new bss and sbss section's size is zero, and its file offset
918 and virtual address should be off by NEW_DATA2_SIZE. */
919 || n == old_sbss_index
922 /* NN should be `old_s?bss_index + 1' at this point. */
923 NEW_SECTION_H (nn).sh_offset =
924 NEW_SECTION_H (new_data2_index).sh_offset + new_data2_size;
925 NEW_SECTION_H (nn).sh_addr =
926 NEW_SECTION_H (new_data2_index).sh_addr + new_data2_size;
927 /* Let the new bss section address alignment be the same as the
928 section address alignment followed the old bss section, so
929 this section will be placed in exactly the same place. */
930 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign;
931 NEW_SECTION_H (nn).sh_size = 0;
933 else
935 /* Any section that was original placed AFTER the bss
936 section should now be off by NEW_DATA2_SIZE. */
937 #ifdef SOLARIS_POWERPC
938 /* On PPC Reference Platform running Solaris 2.5.1
939 the plt section is also of type NOBI like the bss section.
940 (not really stored) and therefore sections after the bss
941 section start at the plt offset. The plt section is always
942 the one just before the bss section.
943 It would be better to put the new data section before
944 the .plt section, or use libelf instead.
945 Erik Deumens, deumens@qtp.ufl.edu. */
946 if (NEW_SECTION_H (nn).sh_offset
947 >= OLD_SECTION_H (old_bss_index-1).sh_offset)
948 NEW_SECTION_H (nn).sh_offset += new_data2_size;
949 #else
950 if (round_up (NEW_SECTION_H (nn).sh_offset,
951 OLD_SECTION_H (old_bss_index).sh_addralign)
952 >= new_data2_offset)
953 NEW_SECTION_H (nn).sh_offset += new_data2_size;
954 #endif
955 /* Any section that was originally placed after the section
956 header table should now be off by the size of one section
957 header table entry. */
958 if (NEW_SECTION_H (nn).sh_offset > new_file_h->e_shoff)
959 NEW_SECTION_H (nn).sh_offset += new_file_h->e_shentsize;
962 /* If any section hdr refers to the section after the new .data
963 section, make it refer to next one because we have inserted
964 a new section in between. */
966 PATCH_INDEX (NEW_SECTION_H (nn).sh_link);
967 /* For symbol tables, info is a symbol table index,
968 so don't change it. */
969 if (NEW_SECTION_H (nn).sh_type != SHT_SYMTAB
970 && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM)
971 PATCH_INDEX (NEW_SECTION_H (nn).sh_info);
973 if (old_sbss_index != -1)
974 if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".sbss"))
976 NEW_SECTION_H (nn).sh_offset =
977 round_up (NEW_SECTION_H (nn).sh_offset,
978 NEW_SECTION_H (nn).sh_addralign);
979 NEW_SECTION_H (nn).sh_type = SHT_PROGBITS;
982 /* Now, start to copy the content of sections. */
983 if (NEW_SECTION_H (nn).sh_type == SHT_NULL
984 || NEW_SECTION_H (nn).sh_type == SHT_NOBITS)
985 continue;
987 /* Write out the sections. .data and .data1 (and data2, called
988 ".data" in the strings table) get copied from the current process
989 instead of the old file. */
990 if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data")
991 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
992 ".sdata")
993 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
994 ".lit4")
995 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
996 ".lit8")
997 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
998 ".sdata1")
999 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
1000 ".data1")
1001 || !strcmp (old_section_names + NEW_SECTION_H (nn).sh_name,
1002 ".sbss"))
1003 src = (caddr_t) OLD_SECTION_H (n).sh_addr;
1004 else
1005 src = old_base + OLD_SECTION_H (n).sh_offset;
1007 memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src,
1008 NEW_SECTION_H (nn).sh_size);
1010 #ifdef __alpha__
1011 /* Update Alpha COFF symbol table: */
1012 if (strcmp (old_section_names + OLD_SECTION_H (n).sh_name, ".mdebug")
1013 == 0)
1015 pHDRR symhdr = (pHDRR) (NEW_SECTION_H (nn).sh_offset + new_base);
1017 symhdr->cbLineOffset += new_data2_size;
1018 symhdr->cbDnOffset += new_data2_size;
1019 symhdr->cbPdOffset += new_data2_size;
1020 symhdr->cbSymOffset += new_data2_size;
1021 symhdr->cbOptOffset += new_data2_size;
1022 symhdr->cbAuxOffset += new_data2_size;
1023 symhdr->cbSsOffset += new_data2_size;
1024 symhdr->cbSsExtOffset += new_data2_size;
1025 symhdr->cbFdOffset += new_data2_size;
1026 symhdr->cbRfdOffset += new_data2_size;
1027 symhdr->cbExtOffset += new_data2_size;
1029 #endif /* __alpha__ */
1031 #if defined (__sony_news) && defined (_SYSTYPE_SYSV)
1032 if (NEW_SECTION_H (nn).sh_type == SHT_MIPS_DEBUG
1033 && old_mdebug_index != -1)
1035 int diff = NEW_SECTION_H(nn).sh_offset
1036 - OLD_SECTION_H(old_mdebug_index).sh_offset;
1037 HDRR *phdr = (HDRR *)(NEW_SECTION_H (nn).sh_offset + new_base);
1039 if (diff)
1041 phdr->cbLineOffset += diff;
1042 phdr->cbDnOffset += diff;
1043 phdr->cbPdOffset += diff;
1044 phdr->cbSymOffset += diff;
1045 phdr->cbOptOffset += diff;
1046 phdr->cbAuxOffset += diff;
1047 phdr->cbSsOffset += diff;
1048 phdr->cbSsExtOffset += diff;
1049 phdr->cbFdOffset += diff;
1050 phdr->cbRfdOffset += diff;
1051 phdr->cbExtOffset += diff;
1054 #endif /* __sony_news && _SYSTYPE_SYSV */
1056 #if __sgi
1057 /* Adjust the HDRR offsets in .mdebug and copy the
1058 line data if it's in its usual 'hole' in the object.
1059 Makes the new file debuggable with dbx.
1060 patches up two problems: the absolute file offsets
1061 in the HDRR record of .mdebug (see /usr/include/syms.h), and
1062 the ld bug that gets the line table in a hole in the
1063 elf file rather than in the .mdebug section proper.
1064 David Anderson. davea@sgi.com Jan 16,1994. */
1065 if (n == old_mdebug_index)
1067 #define MDEBUGADJUST(__ct,__fileaddr) \
1068 if (n_phdrr->__ct > 0) \
1070 n_phdrr->__fileaddr += movement; \
1073 HDRR * o_phdrr = (HDRR *)((byte *)old_base + OLD_SECTION_H (n).sh_offset);
1074 HDRR * n_phdrr = (HDRR *)((byte *)new_base + NEW_SECTION_H (nn).sh_offset);
1075 unsigned movement = new_data2_size;
1077 MDEBUGADJUST (idnMax, cbDnOffset);
1078 MDEBUGADJUST (ipdMax, cbPdOffset);
1079 MDEBUGADJUST (isymMax, cbSymOffset);
1080 MDEBUGADJUST (ioptMax, cbOptOffset);
1081 MDEBUGADJUST (iauxMax, cbAuxOffset);
1082 MDEBUGADJUST (issMax, cbSsOffset);
1083 MDEBUGADJUST (issExtMax, cbSsExtOffset);
1084 MDEBUGADJUST (ifdMax, cbFdOffset);
1085 MDEBUGADJUST (crfd, cbRfdOffset);
1086 MDEBUGADJUST (iextMax, cbExtOffset);
1087 /* The Line Section, being possible off in a hole of the object,
1088 requires special handling. */
1089 if (n_phdrr->cbLine > 0)
1091 if (o_phdrr->cbLineOffset > (OLD_SECTION_H (n).sh_offset
1092 + OLD_SECTION_H (n).sh_size))
1094 /* line data is in a hole in elf. do special copy and adjust
1095 for this ld mistake.
1097 n_phdrr->cbLineOffset += movement;
1099 memcpy (n_phdrr->cbLineOffset + new_base,
1100 o_phdrr->cbLineOffset + old_base, n_phdrr->cbLine);
1102 else
1104 /* somehow line data is in .mdebug as it is supposed to be. */
1105 MDEBUGADJUST (cbLine, cbLineOffset);
1109 #endif /* __sgi */
1111 /* If it is the symbol table, its st_shndx field needs to be patched. */
1112 if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB
1113 || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM)
1115 ElfW(Shdr) *spt = &NEW_SECTION_H (nn);
1116 unsigned int num = spt->sh_size / spt->sh_entsize;
1117 ElfW(Sym) * sym = (ElfW(Sym) *) (NEW_SECTION_H (nn).sh_offset +
1118 new_base);
1119 for (; num--; sym++)
1121 if ((sym->st_shndx == SHN_UNDEF)
1122 || (sym->st_shndx == SHN_ABS)
1123 || (sym->st_shndx == SHN_COMMON))
1124 continue;
1126 PATCH_INDEX (sym->st_shndx);
1131 /* Update the symbol values of _edata and _end. */
1132 for (n = new_file_h->e_shnum - 1; n; n--)
1134 byte *symnames;
1135 ElfW(Sym) *symp, *symendp;
1137 if (NEW_SECTION_H (n).sh_type != SHT_DYNSYM
1138 && NEW_SECTION_H (n).sh_type != SHT_SYMTAB)
1139 continue;
1141 symnames = ((byte *) new_base
1142 + NEW_SECTION_H (NEW_SECTION_H (n).sh_link).sh_offset);
1143 symp = (ElfW(Sym) *) (NEW_SECTION_H (n).sh_offset + new_base);
1144 symendp = (ElfW(Sym) *) ((byte *)symp + NEW_SECTION_H (n).sh_size);
1146 for (; symp < symendp; symp ++)
1147 if (strcmp ((char *) (symnames + symp->st_name), "_end") == 0
1148 || strcmp ((char *) (symnames + symp->st_name), "end") == 0
1149 || strcmp ((char *) (symnames + symp->st_name), "_edata") == 0
1150 || strcmp ((char *) (symnames + symp->st_name), "edata") == 0)
1151 memcpy (&symp->st_value, &new_bss_addr, sizeof (new_bss_addr));
1154 /* This loop seeks out relocation sections for the data section, so
1155 that it can undo relocations performed by the runtime linker. */
1156 for (n = new_file_h->e_shnum - 1; n; n--)
1158 ElfW(Shdr) section = NEW_SECTION_H (n);
1159 switch (section.sh_type) {
1160 default:
1161 break;
1162 case SHT_REL:
1163 case SHT_RELA:
1164 /* This code handles two different size structs, but there should
1165 be no harm in that provided that r_offset is always the first
1166 member. */
1167 nn = section.sh_info;
1168 if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".data")
1169 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1170 ".sdata")
1171 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1172 ".lit4")
1173 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1174 ".lit8")
1175 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1176 ".sdata1")
1177 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1178 ".data1"))
1180 ElfW(Addr) offset = NEW_SECTION_H (nn).sh_addr -
1181 NEW_SECTION_H (nn).sh_offset;
1182 caddr_t reloc = old_base + section.sh_offset, end;
1183 for (end = reloc + section.sh_size; reloc < end;
1184 reloc += section.sh_entsize)
1186 ElfW(Addr) addr = ((ElfW(Rel) *) reloc)->r_offset - offset;
1187 #ifdef __alpha__
1188 /* The Alpha ELF binutils currently have a bug that
1189 sometimes results in relocs that contain all
1190 zeroes. Work around this for now... */
1191 if (((ElfW(Rel) *) reloc)->r_offset == 0)
1192 continue;
1193 #endif
1194 memcpy (new_base + addr, old_base + addr, sizeof(ElfW(Addr)));
1197 break;
1201 #ifdef UNEXEC_USE_MAP_PRIVATE
1202 if (lseek (new_file, 0, SEEK_SET) == -1)
1203 fatal ("Can't rewind (%s): errno %d\n", new_name, errno);
1205 if (write (new_file, new_base, new_file_size) != new_file_size)
1206 fatal ("Can't write (%s): errno %d\n", new_name, errno);
1207 #endif
1209 /* Close the files and make the new file executable. */
1211 if (close (old_file))
1212 fatal ("Can't close (%s): errno %d\n", old_name, errno);
1214 if (close (new_file))
1215 fatal ("Can't close (%s): errno %d\n", new_name, errno);
1217 if (stat (new_name, &stat_buf) == -1)
1218 fatal ("Can't stat (%s): errno %d\n", new_name, errno);
1220 n = umask (777);
1221 umask (n);
1222 stat_buf.st_mode |= 0111 & ~n;
1223 if (chmod (new_name, stat_buf.st_mode) == -1)
1224 fatal ("Can't chmod (%s): errno %d\n", new_name, errno);