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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 #else
410 #include <config.h>
411 extern void fatal (char *, ...);
412 #endif
414 #include <sys/types.h>
415 #include <stdio.h>
416 #include <sys/stat.h>
417 #include <memory.h>
418 #include <string.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 # ifdef __alpha__
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 # define SHT_SYMTAB Elf_sht_symtab
483 # define SHT_DYNSYM Elf_sht_dynsym
484 # define SHT_NULL Elf_sht_null
485 # define SHT_NOBITS Elf_sht_nobits
486 # define SHT_REL Elf_sht_rel
487 # define SHT_RELA Elf_sht_rela
489 # define SHN_UNDEF Elf_eshn_undefined
490 # define SHN_ABS Elf_eshn_absolute
491 # define SHN_COMMON Elf_eshn_common
492 # endif
494 # ifdef __alpha__
495 # include <sys/exec_ecoff.h>
496 # define HDRR struct ecoff_symhdr
497 # define pHDRR HDRR *
498 # endif
499 #endif /* __NetBSD__ */
501 #ifdef __OpenBSD__
502 # include <sys/exec_elf.h>
503 #endif
505 #if __GNU_LIBRARY__ - 0 >= 6
506 # include <link.h> /* get ElfW etc */
507 #endif
509 #ifndef ElfW
510 # ifdef __STDC__
511 # define ElfBitsW(bits, type) Elf##bits##_##type
512 # else
513 # define ElfBitsW(bits, type) Elf/**/bits/**/_/**/type
514 # endif
515 # ifdef _LP64
516 # define ELFSIZE 64
517 # else
518 # define ELFSIZE 32
519 # endif
520 /* This macro expands `bits' before invoking ElfBitsW. */
521 # define ElfExpandBitsW(bits, type) ElfBitsW (bits, type)
522 # define ElfW(type) ElfExpandBitsW (ELFSIZE, type)
523 #endif
525 #ifndef ELF_BSS_SECTION_NAME
526 #define ELF_BSS_SECTION_NAME ".bss"
527 #endif
529 /* Get the address of a particular section or program header entry,
530 * accounting for the size of the entries.
533 On PPC Reference Platform running Solaris 2.5.1
534 the plt section is also of type NOBI like the bss section.
535 (not really stored) and therefore sections after the bss
536 section start at the plt offset. The plt section is always
537 the one just before the bss section.
538 Thus, we modify the test from
539 if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset)
541 if (NEW_SECTION_H (nn).sh_offset >=
542 OLD_SECTION_H (old_bss_index-1).sh_offset)
543 This is just a hack. We should put the new data section
544 before the .plt section.
545 And we should not have this routine at all but use
546 the libelf library to read the old file and create the new
547 file.
548 The changed code is minimal and depends on prep set in m/prep.h
549 Erik Deumens
550 Quantum Theory Project
551 University of Florida
552 deumens@qtp.ufl.edu
553 Apr 23, 1996
556 #define OLD_SECTION_H(n) \
557 (*(ElfW(Shdr) *) ((byte *) old_section_h + old_file_h->e_shentsize * (n)))
558 #define NEW_SECTION_H(n) \
559 (*(ElfW(Shdr) *) ((byte *) new_section_h + new_file_h->e_shentsize * (n)))
560 #define OLD_PROGRAM_H(n) \
561 (*(ElfW(Phdr) *) ((byte *) old_program_h + old_file_h->e_phentsize * (n)))
562 #define NEW_PROGRAM_H(n) \
563 (*(ElfW(Phdr) *) ((byte *) new_program_h + new_file_h->e_phentsize * (n)))
565 #define PATCH_INDEX(n) \
566 do { \
567 if ((int) (n) >= old_bss_index) \
568 (n)++; } while (0)
569 typedef unsigned char byte;
571 /* Round X up to a multiple of Y. */
573 static ElfW(Addr)
574 round_up (x, y)
575 ElfW(Addr) x, y;
577 int rem = x % y;
578 if (rem == 0)
579 return x;
580 return x - rem + y;
583 /* Return the index of the section named NAME.
584 SECTION_NAMES, FILE_NAME and FILE_H give information
585 about the file we are looking in.
587 If we don't find the section NAME, that is a fatal error
588 if NOERROR is 0; we return -1 if NOERROR is nonzero. */
590 static int
591 find_section (name, section_names, file_name, old_file_h, old_section_h, noerror)
592 char *name;
593 char *section_names;
594 char *file_name;
595 ElfW(Ehdr) *old_file_h;
596 ElfW(Shdr) *old_section_h;
597 int noerror;
599 int idx;
601 for (idx = 1; idx < old_file_h->e_shnum; idx++)
603 #ifdef DEBUG
604 fprintf (stderr, "Looking for %s - found %s\n", name,
605 section_names + OLD_SECTION_H (idx).sh_name);
606 #endif
607 if (!strcmp (section_names + OLD_SECTION_H (idx).sh_name,
608 name))
609 break;
611 if (idx == old_file_h->e_shnum)
613 if (noerror)
614 return -1;
615 else
616 fatal ("Can't find %s in %s.\n", name, file_name, 0);
619 return idx;
622 /* ****************************************************************
623 * unexec
625 * driving logic.
627 * In ELF, this works by replacing the old .bss section with a new
628 * .data section, and inserting an empty .bss immediately afterwards.
631 void
632 unexec (new_name, old_name, data_start, bss_start, entry_address)
633 char *new_name, *old_name;
634 unsigned data_start, bss_start, entry_address;
636 int new_file, old_file, new_file_size;
638 /* Pointers to the base of the image of the two files. */
639 caddr_t old_base, new_base;
641 /* Pointers to the file, program and section headers for the old and new
642 * files.
644 ElfW(Ehdr) *old_file_h, *new_file_h;
645 ElfW(Phdr) *old_program_h, *new_program_h;
646 ElfW(Shdr) *old_section_h, *new_section_h;
648 /* Point to the section name table in the old file */
649 char *old_section_names;
651 ElfW(Addr) old_bss_addr, new_bss_addr;
652 ElfW(Word) old_bss_size, new_data2_size;
653 ElfW(Off) new_data2_offset;
654 ElfW(Addr) new_data2_addr;
656 int n, nn;
657 int old_bss_index, old_sbss_index;
658 int old_data_index, new_data2_index;
659 int old_mdebug_index;
660 struct stat stat_buf;
662 /* Open the old file & map it into the address space. */
664 old_file = open (old_name, O_RDONLY);
666 if (old_file < 0)
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);
672 old_base = mmap ((caddr_t) 0, stat_buf.st_size, PROT_READ, MAP_SHARED,
673 old_file, 0);
675 if (old_base == (caddr_t) -1)
676 fatal ("Can't mmap (%s): errno %d\n", old_name, errno);
678 #ifdef DEBUG
679 fprintf (stderr, "mmap (%s, %x) -> %x\n", old_name, stat_buf.st_size,
680 old_base);
681 #endif
683 /* Get pointers to headers & section names */
685 old_file_h = (ElfW(Ehdr) *) old_base;
686 old_program_h = (ElfW(Phdr) *) ((byte *) old_base + old_file_h->e_phoff);
687 old_section_h = (ElfW(Shdr) *) ((byte *) old_base + old_file_h->e_shoff);
688 old_section_names = (char *) old_base
689 + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset;
691 /* Find the mdebug section, if any. */
693 old_mdebug_index = find_section (".mdebug", old_section_names,
694 old_name, old_file_h, old_section_h, 1);
696 /* Find the old .bss section. Figure out parameters of the new
697 * data2 and bss sections.
700 old_bss_index = find_section (".bss", old_section_names,
701 old_name, old_file_h, old_section_h, 0);
703 old_sbss_index = find_section (".sbss", old_section_names,
704 old_name, old_file_h, old_section_h, 1);
705 if (old_sbss_index != -1)
706 if (OLD_SECTION_H (old_sbss_index).sh_type == SHT_PROGBITS)
707 old_sbss_index = -1;
709 if (old_sbss_index == -1)
711 old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr;
712 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size;
713 new_data2_index = old_bss_index;
715 else
717 old_bss_addr = OLD_SECTION_H (old_sbss_index).sh_addr;
718 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size
719 + OLD_SECTION_H (old_sbss_index).sh_size;
720 new_data2_index = old_sbss_index;
723 /* Find the old .data section. Figure out parameters of
724 the new data2 and bss sections. */
726 old_data_index = find_section (".data", old_section_names,
727 old_name, old_file_h, old_section_h, 0);
729 #if defined (emacs) || !defined (DEBUG)
730 new_bss_addr = (ElfW(Addr)) sbrk (0);
731 #else
732 new_bss_addr = old_bss_addr + old_bss_size + 0x1234;
733 #endif
734 new_data2_addr = old_bss_addr;
735 new_data2_size = new_bss_addr - old_bss_addr;
736 new_data2_offset = OLD_SECTION_H (old_data_index).sh_offset +
737 (new_data2_addr - OLD_SECTION_H (old_data_index).sh_addr);
739 #ifdef DEBUG
740 fprintf (stderr, "old_bss_index %d\n", old_bss_index);
741 fprintf (stderr, "old_bss_addr %x\n", old_bss_addr);
742 fprintf (stderr, "old_bss_size %x\n", old_bss_size);
743 fprintf (stderr, "new_bss_addr %x\n", new_bss_addr);
744 fprintf (stderr, "new_data2_addr %x\n", new_data2_addr);
745 fprintf (stderr, "new_data2_size %x\n", new_data2_size);
746 fprintf (stderr, "new_data2_offset %x\n", new_data2_offset);
747 #endif
749 if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size)
750 fatal (".bss shrank when undumping???\n", 0, 0);
752 /* Set the output file to the right size and mmap it. Set
753 * pointers to various interesting objects. stat_buf still has
754 * old_file data.
757 new_file = open (new_name, O_RDWR | O_CREAT, 0666);
758 if (new_file < 0)
759 fatal ("Can't creat (%s): errno %d\n", new_name, errno);
761 new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_data2_size;
763 if (ftruncate (new_file, new_file_size))
764 fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
766 #ifdef UNEXEC_USE_MAP_PRIVATE
767 new_base = mmap ((caddr_t) 0, new_file_size, PROT_READ | PROT_WRITE,
768 MAP_PRIVATE, new_file, 0);
769 #else
770 new_base = mmap ((caddr_t) 0, new_file_size, PROT_READ | PROT_WRITE,
771 MAP_SHARED, new_file, 0);
772 #endif
774 if (new_base == (caddr_t) -1)
775 fatal ("Can't mmap (%s): errno %d\n", new_name, errno);
777 new_file_h = (ElfW(Ehdr) *) new_base;
778 new_program_h = (ElfW(Phdr) *) ((byte *) new_base + old_file_h->e_phoff);
779 new_section_h = (ElfW(Shdr) *)
780 ((byte *) new_base + old_file_h->e_shoff + new_data2_size);
782 /* Make our new file, program and section headers as copies of the
783 * originals.
786 memcpy (new_file_h, old_file_h, old_file_h->e_ehsize);
787 memcpy (new_program_h, old_program_h,
788 old_file_h->e_phnum * old_file_h->e_phentsize);
790 /* Modify the e_shstrndx if necessary. */
791 PATCH_INDEX (new_file_h->e_shstrndx);
793 /* Fix up file header. We'll add one section. Section header is
794 * further away now.
797 new_file_h->e_shoff += new_data2_size;
798 new_file_h->e_shnum += 1;
800 #ifdef DEBUG
801 fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff);
802 fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum);
803 fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff);
804 fprintf (stderr, "New section count %d\n", new_file_h->e_shnum);
805 #endif
807 /* Fix up a new program header. Extend the writable data segment so
808 * that the bss area is covered too. Find that segment by looking
809 * for a segment that ends just before the .bss area. Make sure
810 * that no segments are above the new .data2. Put a loop at the end
811 * to adjust the offset and address of any segment that is above
812 * data2, just in case we decide to allow this later.
815 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
817 /* Compute maximum of all requirements for alignment of section. */
818 ElfW(Word) alignment = (NEW_PROGRAM_H (n)).p_align;
819 if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment)
820 alignment = OLD_SECTION_H (old_bss_index).sh_addralign;
822 #ifdef __sgi
823 /* According to r02kar@x4u2.desy.de (Karsten Kuenne)
824 and oliva@gnu.org (Alexandre Oliva), on IRIX 5.2, we
825 always get "Program segment above .bss" when dumping
826 when the executable doesn't have an sbss section. */
827 if (old_sbss_index != -1)
828 #endif /* __sgi */
829 if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz
830 > (old_sbss_index == -1
831 ? old_bss_addr
832 : round_up (old_bss_addr, alignment)))
833 fatal ("Program segment above .bss in %s\n", old_name, 0);
835 if (NEW_PROGRAM_H (n).p_type == PT_LOAD
836 && (round_up ((NEW_PROGRAM_H (n)).p_vaddr
837 + (NEW_PROGRAM_H (n)).p_filesz,
838 alignment)
839 == round_up (old_bss_addr, alignment)))
840 break;
842 if (n < 0)
843 fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0);
845 /* Make sure that the size includes any padding before the old .bss
846 section. */
847 NEW_PROGRAM_H (n).p_filesz = new_bss_addr - NEW_PROGRAM_H (n).p_vaddr;
848 NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz;
850 #if 0 /* Maybe allow section after data2 - does this ever happen? */
851 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
853 if (NEW_PROGRAM_H (n).p_vaddr
854 && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr)
855 NEW_PROGRAM_H (n).p_vaddr += new_data2_size - old_bss_size;
857 if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset)
858 NEW_PROGRAM_H (n).p_offset += new_data2_size;
860 #endif
862 /* Fix up section headers based on new .data2 section. Any section
863 * whose offset or virtual address is after the new .data2 section
864 * gets its value adjusted. .bss size becomes zero and new address
865 * is set. data2 section header gets added by copying the existing
866 * .data header and modifying the offset, address and size.
868 for (old_data_index = 1; old_data_index < (int) old_file_h->e_shnum;
869 old_data_index++)
870 if (!strcmp (old_section_names + OLD_SECTION_H (old_data_index).sh_name,
871 ".data"))
872 break;
873 if (old_data_index == old_file_h->e_shnum)
874 fatal ("Can't find .data in %s.\n", old_name, 0);
876 /* Walk through all section headers, insert the new data2 section right
877 before the new bss section. */
878 for (n = 1, nn = 1; n < (int) old_file_h->e_shnum; n++, nn++)
880 caddr_t src;
881 /* If it is (s)bss section, insert the new data2 section before it. */
882 /* new_data2_index is the index of either old_sbss or old_bss, that was
883 chosen as a section for new_data2. */
884 if (n == new_data2_index)
886 /* Steal the data section header for this data2 section. */
887 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index),
888 new_file_h->e_shentsize);
890 NEW_SECTION_H (nn).sh_addr = new_data2_addr;
891 NEW_SECTION_H (nn).sh_offset = new_data2_offset;
892 NEW_SECTION_H (nn).sh_size = new_data2_size;
893 /* Use the bss section's alignment. This will assure that the
894 new data2 section always be placed in the same spot as the old
895 bss section by any other application. */
896 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign;
898 /* Now copy over what we have in the memory now. */
899 memcpy (NEW_SECTION_H (nn).sh_offset + new_base,
900 (caddr_t) OLD_SECTION_H (n).sh_addr,
901 new_data2_size);
902 nn++;
905 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
906 old_file_h->e_shentsize);
908 if (n == old_bss_index
909 /* The new bss and sbss section's size is zero, and its file offset
910 and virtual address should be off by NEW_DATA2_SIZE. */
911 || n == old_sbss_index
914 /* NN should be `old_s?bss_index + 1' at this point. */
915 NEW_SECTION_H (nn).sh_offset =
916 NEW_SECTION_H (new_data2_index).sh_offset + new_data2_size;
917 NEW_SECTION_H (nn).sh_addr =
918 NEW_SECTION_H (new_data2_index).sh_addr + new_data2_size;
919 /* Let the new bss section address alignment be the same as the
920 section address alignment followed the old bss section, so
921 this section will be placed in exactly the same place. */
922 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign;
923 NEW_SECTION_H (nn).sh_size = 0;
925 else
927 /* Any section that was original placed AFTER the bss
928 section should now be off by NEW_DATA2_SIZE. */
929 #ifdef SOLARIS_POWERPC
930 /* On PPC Reference Platform running Solaris 2.5.1
931 the plt section is also of type NOBI like the bss section.
932 (not really stored) and therefore sections after the bss
933 section start at the plt offset. The plt section is always
934 the one just before the bss section.
935 It would be better to put the new data section before
936 the .plt section, or use libelf instead.
937 Erik Deumens, deumens@qtp.ufl.edu. */
938 if (NEW_SECTION_H (nn).sh_offset
939 >= OLD_SECTION_H (old_bss_index-1).sh_offset)
940 NEW_SECTION_H (nn).sh_offset += new_data2_size;
941 #else
942 if (round_up (NEW_SECTION_H (nn).sh_offset,
943 OLD_SECTION_H (old_bss_index).sh_addralign)
944 >= new_data2_offset)
945 NEW_SECTION_H (nn).sh_offset += new_data2_size;
946 #endif
947 /* Any section that was originally placed after the section
948 header table should now be off by the size of one section
949 header table entry. */
950 if (NEW_SECTION_H (nn).sh_offset > new_file_h->e_shoff)
951 NEW_SECTION_H (nn).sh_offset += new_file_h->e_shentsize;
954 /* If any section hdr refers to the section after the new .data
955 section, make it refer to next one because we have inserted
956 a new section in between. */
958 PATCH_INDEX (NEW_SECTION_H (nn).sh_link);
959 /* For symbol tables, info is a symbol table index,
960 so don't change it. */
961 if (NEW_SECTION_H (nn).sh_type != SHT_SYMTAB
962 && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM)
963 PATCH_INDEX (NEW_SECTION_H (nn).sh_info);
965 if (old_sbss_index != -1)
966 if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".sbss"))
968 NEW_SECTION_H (nn).sh_offset =
969 round_up (NEW_SECTION_H (nn).sh_offset,
970 NEW_SECTION_H (nn).sh_addralign);
971 NEW_SECTION_H (nn).sh_type = SHT_PROGBITS;
974 /* Now, start to copy the content of sections. */
975 if (NEW_SECTION_H (nn).sh_type == SHT_NULL
976 || NEW_SECTION_H (nn).sh_type == SHT_NOBITS)
977 continue;
979 /* Write out the sections. .data and .data1 (and data2, called
980 ".data" in the strings table) get copied from the current process
981 instead of the old file. */
982 if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data")
983 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
984 ".sdata")
985 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
986 ".lit4")
987 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
988 ".lit8")
989 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
990 ".sdata1")
991 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
992 ".data1")
993 || !strcmp (old_section_names + NEW_SECTION_H (nn).sh_name,
994 ".sbss"))
995 src = (caddr_t) OLD_SECTION_H (n).sh_addr;
996 else
997 src = old_base + OLD_SECTION_H (n).sh_offset;
999 memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src,
1000 NEW_SECTION_H (nn).sh_size);
1002 #ifdef __alpha__
1003 /* Update Alpha COFF symbol table: */
1004 if (strcmp (old_section_names + OLD_SECTION_H (n).sh_name, ".mdebug")
1005 == 0)
1007 pHDRR symhdr = (pHDRR) (NEW_SECTION_H (nn).sh_offset + new_base);
1009 symhdr->cbLineOffset += new_data2_size;
1010 symhdr->cbDnOffset += new_data2_size;
1011 symhdr->cbPdOffset += new_data2_size;
1012 symhdr->cbSymOffset += new_data2_size;
1013 symhdr->cbOptOffset += new_data2_size;
1014 symhdr->cbAuxOffset += new_data2_size;
1015 symhdr->cbSsOffset += new_data2_size;
1016 symhdr->cbSsExtOffset += new_data2_size;
1017 symhdr->cbFdOffset += new_data2_size;
1018 symhdr->cbRfdOffset += new_data2_size;
1019 symhdr->cbExtOffset += new_data2_size;
1021 #endif /* __alpha__ */
1023 #if defined (__sony_news) && defined (_SYSTYPE_SYSV)
1024 if (NEW_SECTION_H (nn).sh_type == SHT_MIPS_DEBUG
1025 && old_mdebug_index != -1)
1027 int diff = NEW_SECTION_H(nn).sh_offset
1028 - OLD_SECTION_H(old_mdebug_index).sh_offset;
1029 HDRR *phdr = (HDRR *)(NEW_SECTION_H (nn).sh_offset + new_base);
1031 if (diff)
1033 phdr->cbLineOffset += diff;
1034 phdr->cbDnOffset += diff;
1035 phdr->cbPdOffset += diff;
1036 phdr->cbSymOffset += diff;
1037 phdr->cbOptOffset += diff;
1038 phdr->cbAuxOffset += diff;
1039 phdr->cbSsOffset += diff;
1040 phdr->cbSsExtOffset += diff;
1041 phdr->cbFdOffset += diff;
1042 phdr->cbRfdOffset += diff;
1043 phdr->cbExtOffset += diff;
1046 #endif /* __sony_news && _SYSTYPE_SYSV */
1048 #if __sgi
1049 /* Adjust the HDRR offsets in .mdebug and copy the
1050 line data if it's in its usual 'hole' in the object.
1051 Makes the new file debuggable with dbx.
1052 patches up two problems: the absolute file offsets
1053 in the HDRR record of .mdebug (see /usr/include/syms.h), and
1054 the ld bug that gets the line table in a hole in the
1055 elf file rather than in the .mdebug section proper.
1056 David Anderson. davea@sgi.com Jan 16,1994. */
1057 if (n == old_mdebug_index)
1059 #define MDEBUGADJUST(__ct,__fileaddr) \
1060 if (n_phdrr->__ct > 0) \
1062 n_phdrr->__fileaddr += movement; \
1065 HDRR * o_phdrr = (HDRR *)((byte *)old_base + OLD_SECTION_H (n).sh_offset);
1066 HDRR * n_phdrr = (HDRR *)((byte *)new_base + NEW_SECTION_H (nn).sh_offset);
1067 unsigned movement = new_data2_size;
1069 MDEBUGADJUST (idnMax, cbDnOffset);
1070 MDEBUGADJUST (ipdMax, cbPdOffset);
1071 MDEBUGADJUST (isymMax, cbSymOffset);
1072 MDEBUGADJUST (ioptMax, cbOptOffset);
1073 MDEBUGADJUST (iauxMax, cbAuxOffset);
1074 MDEBUGADJUST (issMax, cbSsOffset);
1075 MDEBUGADJUST (issExtMax, cbSsExtOffset);
1076 MDEBUGADJUST (ifdMax, cbFdOffset);
1077 MDEBUGADJUST (crfd, cbRfdOffset);
1078 MDEBUGADJUST (iextMax, cbExtOffset);
1079 /* The Line Section, being possible off in a hole of the object,
1080 requires special handling. */
1081 if (n_phdrr->cbLine > 0)
1083 if (o_phdrr->cbLineOffset > (OLD_SECTION_H (n).sh_offset
1084 + OLD_SECTION_H (n).sh_size))
1086 /* line data is in a hole in elf. do special copy and adjust
1087 for this ld mistake.
1089 n_phdrr->cbLineOffset += movement;
1091 memcpy (n_phdrr->cbLineOffset + new_base,
1092 o_phdrr->cbLineOffset + old_base, n_phdrr->cbLine);
1094 else
1096 /* somehow line data is in .mdebug as it is supposed to be. */
1097 MDEBUGADJUST (cbLine, cbLineOffset);
1101 #endif /* __sgi */
1103 /* If it is the symbol table, its st_shndx field needs to be patched. */
1104 if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB
1105 || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM)
1107 ElfW(Shdr) *spt = &NEW_SECTION_H (nn);
1108 unsigned int num = spt->sh_size / spt->sh_entsize;
1109 ElfW(Sym) * sym = (ElfW(Sym) *) (NEW_SECTION_H (nn).sh_offset +
1110 new_base);
1111 for (; num--; sym++)
1113 if ((sym->st_shndx == SHN_UNDEF)
1114 || (sym->st_shndx == SHN_ABS)
1115 || (sym->st_shndx == SHN_COMMON))
1116 continue;
1118 PATCH_INDEX (sym->st_shndx);
1123 /* Update the symbol values of _edata and _end. */
1124 for (n = new_file_h->e_shnum - 1; n; n--)
1126 byte *symnames;
1127 ElfW(Sym) *symp, *symendp;
1129 if (NEW_SECTION_H (n).sh_type != SHT_DYNSYM
1130 && NEW_SECTION_H (n).sh_type != SHT_SYMTAB)
1131 continue;
1133 symnames = ((byte *) new_base
1134 + NEW_SECTION_H (NEW_SECTION_H (n).sh_link).sh_offset);
1135 symp = (ElfW(Sym) *) (NEW_SECTION_H (n).sh_offset + new_base);
1136 symendp = (ElfW(Sym) *) ((byte *)symp + NEW_SECTION_H (n).sh_size);
1138 for (; symp < symendp; symp ++)
1139 if (strcmp ((char *) (symnames + symp->st_name), "_end") == 0
1140 || strcmp ((char *) (symnames + symp->st_name), "end") == 0
1141 || strcmp ((char *) (symnames + symp->st_name), "_edata") == 0
1142 || strcmp ((char *) (symnames + symp->st_name), "edata") == 0)
1143 memcpy (&symp->st_value, &new_bss_addr, sizeof (new_bss_addr));
1146 /* This loop seeks out relocation sections for the data section, so
1147 that it can undo relocations performed by the runtime linker. */
1148 for (n = new_file_h->e_shnum - 1; n; n--)
1150 ElfW(Shdr) section = NEW_SECTION_H (n);
1151 switch (section.sh_type) {
1152 default:
1153 break;
1154 case SHT_REL:
1155 case SHT_RELA:
1156 /* This code handles two different size structs, but there should
1157 be no harm in that provided that r_offset is always the first
1158 member. */
1159 nn = section.sh_info;
1160 if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".data")
1161 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1162 ".sdata")
1163 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1164 ".lit4")
1165 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1166 ".lit8")
1167 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1168 ".sdata1")
1169 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1170 ".data1"))
1172 ElfW(Addr) offset = NEW_SECTION_H (nn).sh_addr -
1173 NEW_SECTION_H (nn).sh_offset;
1174 caddr_t reloc = old_base + section.sh_offset, end;
1175 for (end = reloc + section.sh_size; reloc < end;
1176 reloc += section.sh_entsize)
1178 ElfW(Addr) addr = ((ElfW(Rel) *) reloc)->r_offset - offset;
1179 #ifdef __alpha__
1180 /* The Alpha ELF binutils currently have a bug that
1181 sometimes results in relocs that contain all
1182 zeroes. Work around this for now... */
1183 if (((ElfW(Rel) *) reloc)->r_offset == 0)
1184 continue;
1185 #endif
1186 memcpy (new_base + addr, old_base + addr, sizeof(ElfW(Addr)));
1189 break;
1193 #ifdef UNEXEC_USE_MAP_PRIVATE
1194 if (lseek (new_file, 0, SEEK_SET) == -1)
1195 fatal ("Can't rewind (%s): errno %d\n", new_name, errno);
1197 if (write (new_file, new_base, new_file_size) != new_file_size)
1198 fatal ("Can't write (%s): errno %d\n", new_name, errno);
1199 #endif
1201 /* Close the files and make the new file executable. */
1203 if (close (old_file))
1204 fatal ("Can't close (%s): errno %d\n", old_name, errno);
1206 if (close (new_file))
1207 fatal ("Can't close (%s): errno %d\n", new_name, errno);
1209 if (stat (new_name, &stat_buf) == -1)
1210 fatal ("Can't stat (%s): errno %d\n", new_name, errno);
1212 n = umask (777);
1213 umask (n);
1214 stat_buf.st_mode |= 0111 & ~n;
1215 if (chmod (new_name, stat_buf.st_mode) == -1)
1216 fatal ("Can't chmod (%s): errno %d\n", new_name, errno);