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* unexelf.c (PT_LOAD, SHT_*, SHN_*) [__NetBSD__]: Only provide
[gnu-emacs] / src / unexelf.c
1 /* Copyright (C) 1985, 1986, 1987, 1988, 1990, 1992
2 Free Software Foundation, Inc.
3
4 This file is part of GNU Emacs.
5
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.
10
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.
15
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.
20
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! */
24
25
26 /*
27 * unexec.c - Convert a running program into an a.out file.
28 *
29 * Author: Spencer W. Thomas
30 * Computer Science Dept.
31 * University of Utah
32 * Date: Tue Mar 2 1982
33 * Modified heavily since then.
34 *
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;
39 *
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.
44 *
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.
47 *
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.
54 *
55 * Specifying zero for data_start means the boundary between text and data
56 * should not be the same as when the program was loaded.
57 * If NO_REMAP is defined, the argument data_start is ignored and the
58 * segment boundaries are never changed.
59 *
60 * Bss_start indicates how much of the data segment is to be saved in the
61 * a.out file and restored when the program is executed. It gives the lowest
62 * unsaved address, and is rounded up to a page boundary. The default when 0
63 * is given assumes that the entire data segment is to be stored, including
64 * the previous data and bss as well as any additional storage allocated with
65 * break (2).
66 *
67 * The new file is set up to start at entry_address.
68 *
69 * If you make improvements I'd like to get them too.
70 * harpo!utah-cs!thomas, thomas@Utah-20
71 *
72 */
73
74 /* Even more heavily modified by james@bigtex.cactus.org of Dell Computer Co.
75 * ELF support added.
76 *
77 * Basic theory: the data space of the running process needs to be
78 * dumped to the output file. Normally we would just enlarge the size
79 * of .data, scooting everything down. But we can't do that in ELF,
80 * because there is often something between the .data space and the
81 * .bss space.
82 *
83 * In the temacs dump below, notice that the Global Offset Table
84 * (.got) and the Dynamic link data (.dynamic) come between .data1 and
85 * .bss. It does not work to overlap .data with these fields.
86 *
87 * The solution is to create a new .data segment. This segment is
88 * filled with data from the current process. Since the contents of
89 * various sections refer to sections by index, the new .data segment
90 * is made the last in the table to avoid changing any existing index.
91
92 * This is an example of how the section headers are changed. "Addr"
93 * is a process virtual address. "Offset" is a file offset.
94
95 raid:/nfs/raid/src/dist-18.56/src> dump -h temacs
96
97 temacs:
98
99 **** SECTION HEADER TABLE ****
100 [No] Type Flags Addr Offset Size Name
101 Link Info Adralgn Entsize
102
103 [1] 1 2 0x80480d4 0xd4 0x13 .interp
104 0 0 0x1 0
105
106 [2] 5 2 0x80480e8 0xe8 0x388 .hash
107 3 0 0x4 0x4
108
109 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
110 4 1 0x4 0x10
111
112 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
113 0 0 0x1 0
114
115 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
116 3 7 0x4 0x8
117
118 [6] 1 6 0x8049348 0x1348 0x3 .init
119 0 0 0x4 0
120
121 [7] 1 6 0x804934c 0x134c 0x680 .plt
122 0 0 0x4 0x4
123
124 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
125 0 0 0x4 0
126
127 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
128 0 0 0x4 0
129
130 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
131 0 0 0x4 0
132
133 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
134 0 0 0x4 0
135
136 [12] 1 3 0x8088330 0x3f330 0x20afc .data
137 0 0 0x4 0
138
139 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
140 0 0 0x4 0
141
142 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
143 0 0 0x4 0x4
144
145 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
146 4 0 0x4 0x8
147
148 [16] 8 3 0x80a98f4 0x608f4 0x449c .bss
149 0 0 0x4 0
150
151 [17] 2 0 0 0x608f4 0x9b90 .symtab
152 18 371 0x4 0x10
153
154 [18] 3 0 0 0x6a484 0x8526 .strtab
155 0 0 0x1 0
156
157 [19] 3 0 0 0x729aa 0x93 .shstrtab
158 0 0 0x1 0
159
160 [20] 1 0 0 0x72a3d 0x68b7 .comment
161 0 0 0x1 0
162
163 raid:/nfs/raid/src/dist-18.56/src> dump -h xemacs
164
165 xemacs:
166
167 **** SECTION HEADER TABLE ****
168 [No] Type Flags Addr Offset Size Name
169 Link Info Adralgn Entsize
170
171 [1] 1 2 0x80480d4 0xd4 0x13 .interp
172 0 0 0x1 0
173
174 [2] 5 2 0x80480e8 0xe8 0x388 .hash
175 3 0 0x4 0x4
176
177 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
178 4 1 0x4 0x10
179
180 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
181 0 0 0x1 0
182
183 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
184 3 7 0x4 0x8
185
186 [6] 1 6 0x8049348 0x1348 0x3 .init
187 0 0 0x4 0
188
189 [7] 1 6 0x804934c 0x134c 0x680 .plt
190 0 0 0x4 0x4
191
192 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
193 0 0 0x4 0
194
195 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
196 0 0 0x4 0
197
198 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
199 0 0 0x4 0
200
201 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
202 0 0 0x4 0
203
204 [12] 1 3 0x8088330 0x3f330 0x20afc .data
205 0 0 0x4 0
206
207 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
208 0 0 0x4 0
209
210 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
211 0 0 0x4 0x4
212
213 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
214 4 0 0x4 0x8
215
216 [16] 8 3 0x80c6800 0x7d800 0 .bss
217 0 0 0x4 0
218
219 [17] 2 0 0 0x7d800 0x9b90 .symtab
220 18 371 0x4 0x10
221
222 [18] 3 0 0 0x87390 0x8526 .strtab
223 0 0 0x1 0
224
225 [19] 3 0 0 0x8f8b6 0x93 .shstrtab
226 0 0 0x1 0
227
228 [20] 1 0 0 0x8f949 0x68b7 .comment
229 0 0 0x1 0
230
231 [21] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
232 0 0 0x4 0
233
234 * This is an example of how the file header is changed. "Shoff" is
235 * the section header offset within the file. Since that table is
236 * after the new .data section, it is moved. "Shnum" is the number of
237 * sections, which we increment.
238 *
239 * "Phoff" is the file offset to the program header. "Phentsize" and
240 * "Shentsz" are the program and section header entries sizes respectively.
241 * These can be larger than the apparent struct sizes.
242
243 raid:/nfs/raid/src/dist-18.56/src> dump -f temacs
244
245 temacs:
246
247 **** ELF HEADER ****
248 Class Data Type Machine Version
249 Entry Phoff Shoff Flags Ehsize
250 Phentsize Phnum Shentsz Shnum Shstrndx
251
252 1 1 2 3 1
253 0x80499cc 0x34 0x792f4 0 0x34
254 0x20 5 0x28 21 19
255
256 raid:/nfs/raid/src/dist-18.56/src> dump -f xemacs
257
258 xemacs:
259
260 **** ELF HEADER ****
261 Class Data Type Machine Version
262 Entry Phoff Shoff Flags Ehsize
263 Phentsize Phnum Shentsz Shnum Shstrndx
264
265 1 1 2 3 1
266 0x80499cc 0x34 0x96200 0 0x34
267 0x20 5 0x28 22 19
268
269 * These are the program headers. "Offset" is the file offset to the
270 * segment. "Vaddr" is the memory load address. "Filesz" is the
271 * segment size as it appears in the file, and "Memsz" is the size in
272 * memory. Below, the third segment is the code and the fourth is the
273 * data: the difference between Filesz and Memsz is .bss
274
275 raid:/nfs/raid/src/dist-18.56/src> dump -o temacs
276
277 temacs:
278 ***** PROGRAM EXECUTION HEADER *****
279 Type Offset Vaddr Paddr
280 Filesz Memsz Flags Align
281
282 6 0x34 0x8048034 0
283 0xa0 0xa0 5 0
284
285 3 0xd4 0 0
286 0x13 0 4 0
287
288 1 0x34 0x8048034 0
289 0x3f2f9 0x3f2f9 5 0x1000
290
291 1 0x3f330 0x8088330 0
292 0x215c4 0x25a60 7 0x1000
293
294 2 0x60874 0x80a9874 0
295 0x80 0 7 0
296
297 raid:/nfs/raid/src/dist-18.56/src> dump -o xemacs
298
299 xemacs:
300 ***** PROGRAM EXECUTION HEADER *****
301 Type Offset Vaddr Paddr
302 Filesz Memsz Flags Align
303
304 6 0x34 0x8048034 0
305 0xa0 0xa0 5 0
306
307 3 0xd4 0 0
308 0x13 0 4 0
309
310 1 0x34 0x8048034 0
311 0x3f2f9 0x3f2f9 5 0x1000
312
313 1 0x3f330 0x8088330 0
314 0x3e4d0 0x3e4d0 7 0x1000
315
316 2 0x60874 0x80a9874 0
317 0x80 0 7 0
318
319
320 */
321 \f
322 /* Modified by wtien@urbana.mcd.mot.com of Motorola Inc.
323 *
324 * The above mechanism does not work if the unexeced ELF file is being
325 * re-layout by other applications (such as `strip'). All the applications
326 * that re-layout the internal of ELF will layout all sections in ascending
327 * order of their file offsets. After the re-layout, the data2 section will
328 * still be the LAST section in the section header vector, but its file offset
329 * is now being pushed far away down, and causes part of it not to be mapped
330 * in (ie. not covered by the load segment entry in PHDR vector), therefore
331 * causes the new binary to fail.
332 *
333 * The solution is to modify the unexec algorithm to insert the new data2
334 * section header right before the new bss section header, so their file
335 * offsets will be in the ascending order. Since some of the section's (all
336 * sections AFTER the bss section) indexes are now changed, we also need to
337 * modify some fields to make them point to the right sections. This is done
338 * by macro PATCH_INDEX. All the fields that need to be patched are:
339 *
340 * 1. ELF header e_shstrndx field.
341 * 2. section header sh_link and sh_info field.
342 * 3. symbol table entry st_shndx field.
343 *
344 * The above example now should look like:
345
346 **** SECTION HEADER TABLE ****
347 [No] Type Flags Addr Offset Size Name
348 Link Info Adralgn Entsize
349
350 [1] 1 2 0x80480d4 0xd4 0x13 .interp
351 0 0 0x1 0
352
353 [2] 5 2 0x80480e8 0xe8 0x388 .hash
354 3 0 0x4 0x4
355
356 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
357 4 1 0x4 0x10
358
359 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
360 0 0 0x1 0
361
362 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
363 3 7 0x4 0x8
364
365 [6] 1 6 0x8049348 0x1348 0x3 .init
366 0 0 0x4 0
367
368 [7] 1 6 0x804934c 0x134c 0x680 .plt
369 0 0 0x4 0x4
370
371 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
372 0 0 0x4 0
373
374 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
375 0 0 0x4 0
376
377 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
378 0 0 0x4 0
379
380 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
381 0 0 0x4 0
382
383 [12] 1 3 0x8088330 0x3f330 0x20afc .data
384 0 0 0x4 0
385
386 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
387 0 0 0x4 0
388
389 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
390 0 0 0x4 0x4
391
392 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
393 4 0 0x4 0x8
394
395 [16] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
396 0 0 0x4 0
397
398 [17] 8 3 0x80c6800 0x7d800 0 .bss
399 0 0 0x4 0
400
401 [18] 2 0 0 0x7d800 0x9b90 .symtab
402 19 371 0x4 0x10
403
404 [19] 3 0 0 0x87390 0x8526 .strtab
405 0 0 0x1 0
406
407 [20] 3 0 0 0x8f8b6 0x93 .shstrtab
408 0 0 0x1 0
409
410 [21] 1 0 0 0x8f949 0x68b7 .comment
411 0 0 0x1 0
412
413 */
414 \f
415 #include <sys/types.h>
416 #include <stdio.h>
417 #include <sys/stat.h>
418 #include <memory.h>
419 #include <string.h>
420 #include <errno.h>
421 #include <unistd.h>
422 #include <fcntl.h>
423 #if !defined (__NetBSD__) && !defined (__OpenBSD__)
424 #include <elf.h>
425 #endif
426 #include <sys/mman.h>
427 #if defined (__sony_news) && defined (_SYSTYPE_SYSV)
428 #include <sys/elf_mips.h>
429 #include <sym.h>
430 #endif /* __sony_news && _SYSTYPE_SYSV */
431 #if __sgi
432 #include <syms.h> /* for HDRR declaration */
433 #endif /* __sgi */
434
435 #if defined (__alpha__) && !defined (__NetBSD__) && !defined (__OpenBSD__)
436 /* Declare COFF debugging symbol table. This used to be in
437 /usr/include/sym.h, but this file is no longer included in Red Hat
438 5.0 and presumably in any other glibc 2.x based distribution. */
439 typedef struct {
440 short magic;
441 short vstamp;
442 int ilineMax;
443 int idnMax;
444 int ipdMax;
445 int isymMax;
446 int ioptMax;
447 int iauxMax;
448 int issMax;
449 int issExtMax;
450 int ifdMax;
451 int crfd;
452 int iextMax;
453 long cbLine;
454 long cbLineOffset;
455 long cbDnOffset;
456 long cbPdOffset;
457 long cbSymOffset;
458 long cbOptOffset;
459 long cbAuxOffset;
460 long cbSsOffset;
461 long cbSsExtOffset;
462 long cbFdOffset;
463 long cbRfdOffset;
464 long cbExtOffset;
465 } HDRR, *pHDRR;
466 #define cbHDRR sizeof(HDRR)
467 #define hdrNil ((pHDRR)0)
468 #endif
469
470 #ifdef __NetBSD__
471 /*
472 * NetBSD does not have normal-looking user-land ELF support.
473 */
474 # ifdef __alpha__
475 # define ELFSIZE 64
476 # else
477 # define ELFSIZE 32
478 # endif
479 # include <sys/exec_elf.h>
480
481 # ifndef PT_LOAD
482 # define PT_LOAD Elf_pt_load
483 # define SHT_SYMTAB Elf_sht_symtab
484 # define SHT_DYNSYM Elf_sht_dynsym
485 # define SHT_NULL Elf_sht_null
486 # define SHT_NOBITS Elf_sht_nobits
487 # define SHT_REL Elf_sht_rel
488 # define SHT_RELA Elf_sht_rela
489
490 # define SHN_UNDEF Elf_eshn_undefined
491 # define SHN_ABS Elf_eshn_absolute
492 # define SHN_COMMON Elf_eshn_common
493 # endif
494
495 # ifdef __alpha__
496 # include <sys/exec_ecoff.h>
497 # define HDRR struct ecoff_symhdr
498 # define pHDRR HDRR *
499 # endif
500 #endif /* __NetBSD__ */
501
502 #ifdef __OpenBSD__
503 # include <sys/exec_elf.h>
504 #endif
505
506 #if __GNU_LIBRARY__ - 0 >= 6
507 # include <link.h> /* get ElfW etc */
508 #endif
509
510 #ifndef ElfW
511 # ifdef __STDC__
512 # define ElfW(type) Elf32_##type
513 # else
514 # define ElfW(type) Elf32_/**/type
515 # endif
516 #endif
517
518 #ifndef emacs
519 #define fatal(a, b, c) fprintf (stderr, a, b, c), exit (1)
520 #else
521 #include <config.h>
522 extern void fatal (char *, ...);
523 #endif
524
525 #ifndef ELF_BSS_SECTION_NAME
526 #define ELF_BSS_SECTION_NAME ".bss"
527 #endif
528
529 /* Get the address of a particular section or program header entry,
530 * accounting for the size of the entries.
531 */
532 /*
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)
540 to
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
554 */
555
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)))
564
565 #define PATCH_INDEX(n) \
566 do { \
567 if ((int) (n) >= old_bss_index) \
568 (n)++; } while (0)
569 typedef unsigned char byte;
570
571 /* Round X up to a multiple of Y. */
572
573 static ElfW(Addr)
574 round_up (x, y)
575 ElfW(Addr) x, y;
576 {
577 int rem = x % y;
578 if (rem == 0)
579 return x;
580 return x - rem + y;
581 }
582
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.
586
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. */
589
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;
598 {
599 int idx;
600
601 for (idx = 1; idx < old_file_h->e_shnum; idx++)
602 {
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;
610 }
611 if (idx == old_file_h->e_shnum)
612 {
613 if (noerror)
614 return -1;
615 else
616 fatal ("Can't find %s in %s.\n", name, file_name, 0);
617 }
618
619 return idx;
620 }
621
622 /* ****************************************************************
623 * unexec
624 *
625 * driving logic.
626 *
627 * In ELF, this works by replacing the old .bss section with a new
628 * .data section, and inserting an empty .bss immediately afterwards.
629 *
630 */
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;
635 {
636 int new_file, old_file, new_file_size;
637
638 /* Pointers to the base of the image of the two files. */
639 caddr_t old_base, new_base;
640
641 /* Pointers to the file, program and section headers for the old and new
642 * files.
643 */
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;
647
648 /* Point to the section name table in the old file */
649 char *old_section_names;
650
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;
655
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;
661
662 /* Open the old file & map it into the address space. */
663
664 old_file = open (old_name, O_RDONLY);
665
666 if (old_file < 0)
667 fatal ("Can't open %s for reading: errno %d\n", old_name, errno);
668
669 if (fstat (old_file, &stat_buf) == -1)
670 fatal ("Can't fstat (%s): errno %d\n", old_name, errno);
671
672 old_base = mmap ((caddr_t) 0, stat_buf.st_size, PROT_READ, MAP_SHARED,
673 old_file, 0);
674
675 if (old_base == (caddr_t) -1)
676 fatal ("Can't mmap (%s): errno %d\n", old_name, errno);
677
678 #ifdef DEBUG
679 fprintf (stderr, "mmap (%s, %x) -> %x\n", old_name, stat_buf.st_size,
680 old_base);
681 #endif
682
683 /* Get pointers to headers & section names */
684
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;
690
691 /* Find the mdebug section, if any. */
692
693 old_mdebug_index = find_section (".mdebug", old_section_names,
694 old_name, old_file_h, old_section_h, 1);
695
696 /* Find the old .bss section. Figure out parameters of the new
697 * data2 and bss sections.
698 */
699
700 old_bss_index = find_section (".bss", old_section_names,
701 old_name, old_file_h, old_section_h, 0);
702
703 old_sbss_index = find_section (".sbss", old_section_names,
704 old_name, old_file_h, old_section_h, 1);
705
706 if (old_sbss_index == -1)
707 {
708 old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr;
709 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size;
710 new_data2_index = old_bss_index;
711 }
712 else
713 {
714 old_bss_addr = OLD_SECTION_H (old_sbss_index).sh_addr;
715 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size
716 + OLD_SECTION_H (old_sbss_index).sh_size;
717 new_data2_index = old_sbss_index;
718 }
719
720 /* Find the old .data section. Figure out parameters of
721 the new data2 and bss sections. */
722
723 old_data_index = find_section (".data", old_section_names,
724 old_name, old_file_h, old_section_h, 0);
725
726 #if defined (emacs) || !defined (DEBUG)
727 new_bss_addr = (ElfW(Addr)) sbrk (0);
728 #else
729 new_bss_addr = old_bss_addr + old_bss_size + 0x1234;
730 #endif
731 new_data2_addr = old_bss_addr;
732 new_data2_size = new_bss_addr - old_bss_addr;
733 new_data2_offset = OLD_SECTION_H (old_data_index).sh_offset +
734 (new_data2_addr - OLD_SECTION_H (old_data_index).sh_addr);
735
736 #ifdef DEBUG
737 fprintf (stderr, "old_bss_index %d\n", old_bss_index);
738 fprintf (stderr, "old_bss_addr %x\n", old_bss_addr);
739 fprintf (stderr, "old_bss_size %x\n", old_bss_size);
740 fprintf (stderr, "new_bss_addr %x\n", new_bss_addr);
741 fprintf (stderr, "new_data2_addr %x\n", new_data2_addr);
742 fprintf (stderr, "new_data2_size %x\n", new_data2_size);
743 fprintf (stderr, "new_data2_offset %x\n", new_data2_offset);
744 #endif
745
746 if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size)
747 fatal (".bss shrank when undumping???\n", 0, 0);
748
749 /* Set the output file to the right size and mmap it. Set
750 * pointers to various interesting objects. stat_buf still has
751 * old_file data.
752 */
753
754 new_file = open (new_name, O_RDWR | O_CREAT, 0666);
755 if (new_file < 0)
756 fatal ("Can't creat (%s): errno %d\n", new_name, errno);
757
758 new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_data2_size;
759
760 if (ftruncate (new_file, new_file_size))
761 fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
762
763 #ifdef UNEXEC_USE_MAP_PRIVATE
764 new_base = mmap ((caddr_t) 0, new_file_size, PROT_READ | PROT_WRITE,
765 MAP_PRIVATE, new_file, 0);
766 #else
767 new_base = mmap ((caddr_t) 0, new_file_size, PROT_READ | PROT_WRITE,
768 MAP_SHARED, new_file, 0);
769 #endif
770
771 if (new_base == (caddr_t) -1)
772 fatal ("Can't mmap (%s): errno %d\n", new_name, errno);
773
774 new_file_h = (ElfW(Ehdr) *) new_base;
775 new_program_h = (ElfW(Phdr) *) ((byte *) new_base + old_file_h->e_phoff);
776 new_section_h = (ElfW(Shdr) *)
777 ((byte *) new_base + old_file_h->e_shoff + new_data2_size);
778
779 /* Make our new file, program and section headers as copies of the
780 * originals.
781 */
782
783 memcpy (new_file_h, old_file_h, old_file_h->e_ehsize);
784 memcpy (new_program_h, old_program_h,
785 old_file_h->e_phnum * old_file_h->e_phentsize);
786
787 /* Modify the e_shstrndx if necessary. */
788 PATCH_INDEX (new_file_h->e_shstrndx);
789
790 /* Fix up file header. We'll add one section. Section header is
791 * further away now.
792 */
793
794 new_file_h->e_shoff += new_data2_size;
795 new_file_h->e_shnum += 1;
796
797 #ifdef DEBUG
798 fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff);
799 fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum);
800 fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff);
801 fprintf (stderr, "New section count %d\n", new_file_h->e_shnum);
802 #endif
803
804 /* Fix up a new program header. Extend the writable data segment so
805 * that the bss area is covered too. Find that segment by looking
806 * for a segment that ends just before the .bss area. Make sure
807 * that no segments are above the new .data2. Put a loop at the end
808 * to adjust the offset and address of any segment that is above
809 * data2, just in case we decide to allow this later.
810 */
811
812 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
813 {
814 /* Compute maximum of all requirements for alignment of section. */
815 ElfW(Word) alignment = (NEW_PROGRAM_H (n)).p_align;
816 if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment)
817 alignment = OLD_SECTION_H (old_bss_index).sh_addralign;
818
819 #ifdef __sgi
820 /* According to r02kar@x4u2.desy.de (Karsten Kuenne)
821 and oliva@gnu.org (Alexandre Oliva), on IRIX 5.2, we
822 always get "Program segment above .bss" when dumping
823 when the executable doesn't have an sbss section. */
824 if (old_sbss_index != -1)
825 #endif /* __sgi */
826 if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz
827 > (old_sbss_index == -1
828 ? old_bss_addr
829 : round_up (old_bss_addr, alignment)))
830 fatal ("Program segment above .bss in %s\n", old_name, 0);
831
832 if (NEW_PROGRAM_H (n).p_type == PT_LOAD
833 && (round_up ((NEW_PROGRAM_H (n)).p_vaddr
834 + (NEW_PROGRAM_H (n)).p_filesz,
835 alignment)
836 == round_up (old_bss_addr, alignment)))
837 break;
838 }
839 if (n < 0)
840 fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0);
841
842 /* Make sure that the size includes any padding before the old .bss
843 section. */
844 NEW_PROGRAM_H (n).p_filesz = new_bss_addr - NEW_PROGRAM_H (n).p_vaddr;
845 NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz;
846
847 #if 0 /* Maybe allow section after data2 - does this ever happen? */
848 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
849 {
850 if (NEW_PROGRAM_H (n).p_vaddr
851 && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr)
852 NEW_PROGRAM_H (n).p_vaddr += new_data2_size - old_bss_size;
853
854 if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset)
855 NEW_PROGRAM_H (n).p_offset += new_data2_size;
856 }
857 #endif
858
859 /* Fix up section headers based on new .data2 section. Any section
860 * whose offset or virtual address is after the new .data2 section
861 * gets its value adjusted. .bss size becomes zero and new address
862 * is set. data2 section header gets added by copying the existing
863 * .data header and modifying the offset, address and size.
864 */
865 for (old_data_index = 1; old_data_index < (int) old_file_h->e_shnum;
866 old_data_index++)
867 if (!strcmp (old_section_names + OLD_SECTION_H (old_data_index).sh_name,
868 ".data"))
869 break;
870 if (old_data_index == old_file_h->e_shnum)
871 fatal ("Can't find .data in %s.\n", old_name, 0);
872
873 /* Walk through all section headers, insert the new data2 section right
874 before the new bss section. */
875 for (n = 1, nn = 1; n < (int) old_file_h->e_shnum; n++, nn++)
876 {
877 caddr_t src;
878 /* If it is (s)bss section, insert the new data2 section before it. */
879 /* new_data2_index is the index of either old_sbss or old_bss, that was
880 chosen as a section for new_data2. */
881 if (n == new_data2_index)
882 {
883 /* Steal the data section header for this data2 section. */
884 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index),
885 new_file_h->e_shentsize);
886
887 NEW_SECTION_H (nn).sh_addr = new_data2_addr;
888 NEW_SECTION_H (nn).sh_offset = new_data2_offset;
889 NEW_SECTION_H (nn).sh_size = new_data2_size;
890 /* Use the bss section's alignment. This will assure that the
891 new data2 section always be placed in the same spot as the old
892 bss section by any other application. */
893 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign;
894
895 /* Now copy over what we have in the memory now. */
896 memcpy (NEW_SECTION_H (nn).sh_offset + new_base,
897 (caddr_t) OLD_SECTION_H (n).sh_addr,
898 new_data2_size);
899 nn++;
900 }
901
902 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
903 old_file_h->e_shentsize);
904
905 if (n == old_bss_index
906 /* The new bss and sbss section's size is zero, and its file offset
907 and virtual address should be off by NEW_DATA2_SIZE. */
908 || n == old_sbss_index
909 )
910 {
911 /* NN should be `old_s?bss_index + 1' at this point. */
912 NEW_SECTION_H (nn).sh_offset =
913 NEW_SECTION_H (new_data2_index).sh_offset + new_data2_size;
914 NEW_SECTION_H (nn).sh_addr =
915 NEW_SECTION_H (new_data2_index).sh_addr + new_data2_size;
916 /* Let the new bss section address alignment be the same as the
917 section address alignment followed the old bss section, so
918 this section will be placed in exactly the same place. */
919 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign;
920 NEW_SECTION_H (nn).sh_size = 0;
921 }
922 else
923 {
924 /* Any section that was original placed AFTER the bss
925 section should now be off by NEW_DATA2_SIZE. */
926 #ifdef SOLARIS_POWERPC
927 /* On PPC Reference Platform running Solaris 2.5.1
928 the plt section is also of type NOBI like the bss section.
929 (not really stored) and therefore sections after the bss
930 section start at the plt offset. The plt section is always
931 the one just before the bss section.
932 It would be better to put the new data section before
933 the .plt section, or use libelf instead.
934 Erik Deumens, deumens@qtp.ufl.edu. */
935 if (NEW_SECTION_H (nn).sh_offset
936 >= OLD_SECTION_H (old_bss_index-1).sh_offset)
937 NEW_SECTION_H (nn).sh_offset += new_data2_size;
938 #else
939 if (round_up (NEW_SECTION_H (nn).sh_offset,
940 OLD_SECTION_H (old_bss_index).sh_addralign)
941 >= new_data2_offset)
942 NEW_SECTION_H (nn).sh_offset += new_data2_size;
943 #endif
944 /* Any section that was originally placed after the section
945 header table should now be off by the size of one section
946 header table entry. */
947 if (NEW_SECTION_H (nn).sh_offset > new_file_h->e_shoff)
948 NEW_SECTION_H (nn).sh_offset += new_file_h->e_shentsize;
949 }
950
951 /* If any section hdr refers to the section after the new .data
952 section, make it refer to next one because we have inserted
953 a new section in between. */
954
955 PATCH_INDEX (NEW_SECTION_H (nn).sh_link);
956 /* For symbol tables, info is a symbol table index,
957 so don't change it. */
958 if (NEW_SECTION_H (nn).sh_type != SHT_SYMTAB
959 && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM)
960 PATCH_INDEX (NEW_SECTION_H (nn).sh_info);
961
962 /* Now, start to copy the content of sections. */
963 if (NEW_SECTION_H (nn).sh_type == SHT_NULL
964 || NEW_SECTION_H (nn).sh_type == SHT_NOBITS)
965 continue;
966
967 /* Write out the sections. .data and .data1 (and data2, called
968 ".data" in the strings table) get copied from the current process
969 instead of the old file. */
970 if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data")
971 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
972 ".sdata")
973 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
974 ".lit4")
975 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
976 ".lit8")
977 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
978 ".sdata1")
979 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
980 ".data1"))
981 src = (caddr_t) OLD_SECTION_H (n).sh_addr;
982 else
983 src = old_base + OLD_SECTION_H (n).sh_offset;
984
985 memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src,
986 NEW_SECTION_H (nn).sh_size);
987
988 #ifdef __alpha__
989 /* Update Alpha COFF symbol table: */
990 if (strcmp (old_section_names + OLD_SECTION_H (n).sh_name, ".mdebug")
991 == 0)
992 {
993 pHDRR symhdr = (pHDRR) (NEW_SECTION_H (nn).sh_offset + new_base);
994
995 symhdr->cbLineOffset += new_data2_size;
996 symhdr->cbDnOffset += new_data2_size;
997 symhdr->cbPdOffset += new_data2_size;
998 symhdr->cbSymOffset += new_data2_size;
999 symhdr->cbOptOffset += new_data2_size;
1000 symhdr->cbAuxOffset += new_data2_size;
1001 symhdr->cbSsOffset += new_data2_size;
1002 symhdr->cbSsExtOffset += new_data2_size;
1003 symhdr->cbFdOffset += new_data2_size;
1004 symhdr->cbRfdOffset += new_data2_size;
1005 symhdr->cbExtOffset += new_data2_size;
1006 }
1007 #endif /* __alpha__ */
1008
1009 #if defined (__sony_news) && defined (_SYSTYPE_SYSV)
1010 if (NEW_SECTION_H (nn).sh_type == SHT_MIPS_DEBUG
1011 && old_mdebug_index != -1)
1012 {
1013 int diff = NEW_SECTION_H(nn).sh_offset
1014 - OLD_SECTION_H(old_mdebug_index).sh_offset;
1015 HDRR *phdr = (HDRR *)(NEW_SECTION_H (nn).sh_offset + new_base);
1016
1017 if (diff)
1018 {
1019 phdr->cbLineOffset += diff;
1020 phdr->cbDnOffset += diff;
1021 phdr->cbPdOffset += diff;
1022 phdr->cbSymOffset += diff;
1023 phdr->cbOptOffset += diff;
1024 phdr->cbAuxOffset += diff;
1025 phdr->cbSsOffset += diff;
1026 phdr->cbSsExtOffset += diff;
1027 phdr->cbFdOffset += diff;
1028 phdr->cbRfdOffset += diff;
1029 phdr->cbExtOffset += diff;
1030 }
1031 }
1032 #endif /* __sony_news && _SYSTYPE_SYSV */
1033
1034 #if __sgi
1035 /* Adjust the HDRR offsets in .mdebug and copy the
1036 line data if it's in its usual 'hole' in the object.
1037 Makes the new file debuggable with dbx.
1038 patches up two problems: the absolute file offsets
1039 in the HDRR record of .mdebug (see /usr/include/syms.h), and
1040 the ld bug that gets the line table in a hole in the
1041 elf file rather than in the .mdebug section proper.
1042 David Anderson. davea@sgi.com Jan 16,1994. */
1043 if (n == old_mdebug_index)
1044 {
1045 #define MDEBUGADJUST(__ct,__fileaddr) \
1046 if (n_phdrr->__ct > 0) \
1047 { \
1048 n_phdrr->__fileaddr += movement; \
1049 }
1050
1051 HDRR * o_phdrr = (HDRR *)((byte *)old_base + OLD_SECTION_H (n).sh_offset);
1052 HDRR * n_phdrr = (HDRR *)((byte *)new_base + NEW_SECTION_H (nn).sh_offset);
1053 unsigned movement = new_data2_size;
1054
1055 MDEBUGADJUST (idnMax, cbDnOffset);
1056 MDEBUGADJUST (ipdMax, cbPdOffset);
1057 MDEBUGADJUST (isymMax, cbSymOffset);
1058 MDEBUGADJUST (ioptMax, cbOptOffset);
1059 MDEBUGADJUST (iauxMax, cbAuxOffset);
1060 MDEBUGADJUST (issMax, cbSsOffset);
1061 MDEBUGADJUST (issExtMax, cbSsExtOffset);
1062 MDEBUGADJUST (ifdMax, cbFdOffset);
1063 MDEBUGADJUST (crfd, cbRfdOffset);
1064 MDEBUGADJUST (iextMax, cbExtOffset);
1065 /* The Line Section, being possible off in a hole of the object,
1066 requires special handling. */
1067 if (n_phdrr->cbLine > 0)
1068 {
1069 if (o_phdrr->cbLineOffset > (OLD_SECTION_H (n).sh_offset
1070 + OLD_SECTION_H (n).sh_size))
1071 {
1072 /* line data is in a hole in elf. do special copy and adjust
1073 for this ld mistake.
1074 */
1075 n_phdrr->cbLineOffset += movement;
1076
1077 memcpy (n_phdrr->cbLineOffset + new_base,
1078 o_phdrr->cbLineOffset + old_base, n_phdrr->cbLine);
1079 }
1080 else
1081 {
1082 /* somehow line data is in .mdebug as it is supposed to be. */
1083 MDEBUGADJUST (cbLine, cbLineOffset);
1084 }
1085 }
1086 }
1087 #endif /* __sgi */
1088
1089 /* If it is the symbol table, its st_shndx field needs to be patched. */
1090 if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB
1091 || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM)
1092 {
1093 ElfW(Shdr) *spt = &NEW_SECTION_H (nn);
1094 unsigned int num = spt->sh_size / spt->sh_entsize;
1095 ElfW(Sym) * sym = (ElfW(Sym) *) (NEW_SECTION_H (nn).sh_offset +
1096 new_base);
1097 for (; num--; sym++)
1098 {
1099 if ((sym->st_shndx == SHN_UNDEF)
1100 || (sym->st_shndx == SHN_ABS)
1101 || (sym->st_shndx == SHN_COMMON))
1102 continue;
1103
1104 PATCH_INDEX (sym->st_shndx);
1105 }
1106 }
1107 }
1108
1109 /* Update the symbol values of _edata and _end. */
1110 for (n = new_file_h->e_shnum - 1; n; n--)
1111 {
1112 byte *symnames;
1113 ElfW(Sym) *symp, *symendp;
1114
1115 if (NEW_SECTION_H (n).sh_type != SHT_DYNSYM
1116 && NEW_SECTION_H (n).sh_type != SHT_SYMTAB)
1117 continue;
1118
1119 symnames = ((byte *) new_base
1120 + NEW_SECTION_H (NEW_SECTION_H (n).sh_link).sh_offset);
1121 symp = (ElfW(Sym) *) (NEW_SECTION_H (n).sh_offset + new_base);
1122 symendp = (ElfW(Sym) *) ((byte *)symp + NEW_SECTION_H (n).sh_size);
1123
1124 for (; symp < symendp; symp ++)
1125 if (strcmp ((char *) (symnames + symp->st_name), "_end") == 0
1126 || strcmp ((char *) (symnames + symp->st_name), "end") == 0
1127 || strcmp ((char *) (symnames + symp->st_name), "_edata") == 0
1128 || strcmp ((char *) (symnames + symp->st_name), "edata") == 0)
1129 memcpy (&symp->st_value, &new_bss_addr, sizeof (new_bss_addr));
1130 }
1131
1132 /* This loop seeks out relocation sections for the data section, so
1133 that it can undo relocations performed by the runtime linker. */
1134 for (n = new_file_h->e_shnum - 1; n; n--)
1135 {
1136 ElfW(Shdr) section = NEW_SECTION_H (n);
1137 switch (section.sh_type) {
1138 default:
1139 break;
1140 case SHT_REL:
1141 case SHT_RELA:
1142 /* This code handles two different size structs, but there should
1143 be no harm in that provided that r_offset is always the first
1144 member. */
1145 nn = section.sh_info;
1146 if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".data")
1147 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1148 ".sdata")
1149 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1150 ".lit4")
1151 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1152 ".lit8")
1153 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1154 ".sdata1")
1155 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1156 ".data1"))
1157 {
1158 ElfW(Addr) offset = NEW_SECTION_H (nn).sh_addr -
1159 NEW_SECTION_H (nn).sh_offset;
1160 caddr_t reloc = old_base + section.sh_offset, end;
1161 for (end = reloc + section.sh_size; reloc < end;
1162 reloc += section.sh_entsize)
1163 {
1164 ElfW(Addr) addr = ((ElfW(Rel) *) reloc)->r_offset - offset;
1165 #ifdef __alpha__
1166 /* The Alpha ELF binutils currently have a bug that
1167 sometimes results in relocs that contain all
1168 zeroes. Work around this for now... */
1169 if (((ElfW(Rel) *) reloc)->r_offset == 0)
1170 continue;
1171 #endif
1172 memcpy (new_base + addr, old_base + addr, sizeof(ElfW(Addr)));
1173 }
1174 }
1175 break;
1176 }
1177 }
1178
1179 #ifdef UNEXEC_USE_MAP_PRIVATE
1180 if (lseek (new_file, 0, SEEK_SET) == -1)
1181 fatal ("Can't rewind (%s): errno %d\n", new_name, errno);
1182
1183 if (write (new_file, new_base, new_file_size) != new_file_size)
1184 fatal ("Can't write (%s): errno %d\n", new_name, errno);
1185 #endif
1186
1187 /* Close the files and make the new file executable. */
1188
1189 if (close (old_file))
1190 fatal ("Can't close (%s): errno %d\n", old_name, errno);
1191
1192 if (close (new_file))
1193 fatal ("Can't close (%s): errno %d\n", new_name, errno);
1194
1195 if (stat (new_name, &stat_buf) == -1)
1196 fatal ("Can't stat (%s): errno %d\n", new_name, errno);
1197
1198 n = umask (777);
1199 umask (n);
1200 stat_buf.st_mode |= 0111 & ~n;
1201 if (chmod (new_name, stat_buf.st_mode) == -1)
1202 fatal ("Can't chmod (%s): errno %d\n", new_name, errno);
1203 }