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comparison src/unexelfsgi.c @ 428:3ecd8885ac67 r21-2-22

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date Mon, 13 Aug 2007 11:28:15 +0200
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1 /* Copyright (C) 1985, 1986, 1987, 1988, 1990, 1992
2 Free Software Foundation, Inc.
3
4 This file is part of XEmacs.
5
6 XEmacs is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
9 later version.
10
11 XEmacs is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with XEmacs; 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 /* Synched up with: FSF 19.31. */
22
23
24 /*
25 * unexec.c - Convert a running program into an a.out file.
26 *
27 * Author: Spencer W. Thomas
28 * Computer Science Dept.
29 * University of Utah
30 * Date: Tue Mar 2 1982
31 * Modified heavily since then.
32 *
33 * Synopsis:
34 * unexec (new_name, a_name, data_start, bss_start, entry_address)
35 * char *new_name, *a_name;
36 * unsigned data_start, bss_start, entry_address;
37 *
38 * Takes a snapshot of the program and makes an a.out format file in the
39 * file named by the string argument new_name.
40 * If a_name is non-NULL, the symbol table will be taken from the given file.
41 * On some machines, an existing a_name file is required.
42 *
43 * The boundaries within the a.out file may be adjusted with the data_start
44 * and bss_start arguments. Either or both may be given as 0 for defaults.
45 *
46 * Data_start gives the boundary between the text segment and the data
47 * segment of the program. The text segment can contain shared, read-only
48 * program code and literal data, while the data segment is always unshared
49 * and unprotected. Data_start gives the lowest unprotected address.
50 * The value you specify may be rounded down to a suitable boundary
51 * as required by the machine you are using.
52 *
53 * Specifying zero for data_start means the boundary between text and data
54 * should not be the same as when the program was loaded.
55 * If NO_REMAP is defined, the argument data_start is ignored and the
56 * segment boundaries are never changed.
57 *
58 * Bss_start indicates how much of the data segment is to be saved in the
59 * a.out file and restored when the program is executed. It gives the lowest
60 * unsaved address, and is rounded up to a page boundary. The default when 0
61 * is given assumes that the entire data segment is to be stored, including
62 * the previous data and bss as well as any additional storage allocated with
63 * break (2).
64 *
65 * The new file is set up to start at entry_address.
66 *
67 * If you make improvements I'd like to get them too.
68 * harpo!utah-cs!thomas, thomas@Utah-20
69 *
70 */
71
72 /* Even more heavily modified by james@bigtex.cactus.org of Dell Computer Co.
73 * ELF support added.
74 *
75 * Basic theory: the data space of the running process needs to be
76 * dumped to the output file. Normally we would just enlarge the size
77 * of .data, scooting everything down. But we can't do that in ELF,
78 * because there is often something between the .data space and the
79 * .bss space.
80 *
81 * In the temacs dump below, notice that the Global Offset Table
82 * (.got) and the Dynamic link data (.dynamic) come between .data1 and
83 * .bss. It does not work to overlap .data with these fields.
84 *
85 * The solution is to create a new .data segment. This segment is
86 * filled with data from the current process. Since the contents of
87 * various sections refer to sections by index, the new .data segment
88 * is made the last in the table to avoid changing any existing index.
89
90 * This is an example of how the section headers are changed. "Addr"
91 * is a process virtual address. "Offset" is a file offset.
92
93 raid:/nfs/raid/src/dist-18.56/src> dump -h temacs
94
95 temacs:
96
97 **** SECTION HEADER TABLE ****
98 [No] Type Flags Addr Offset Size Name
99 Link Info Adralgn Entsize
100
101 [1] 1 2 0x80480d4 0xd4 0x13 .interp
102 0 0 0x1 0
103
104 [2] 5 2 0x80480e8 0xe8 0x388 .hash
105 3 0 0x4 0x4
106
107 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
108 4 1 0x4 0x10
109
110 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
111 0 0 0x1 0
112
113 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
114 3 7 0x4 0x8
115
116 [6] 1 6 0x8049348 0x1348 0x3 .init
117 0 0 0x4 0
118
119 [7] 1 6 0x804934c 0x134c 0x680 .plt
120 0 0 0x4 0x4
121
122 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
123 0 0 0x4 0
124
125 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
126 0 0 0x4 0
127
128 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
129 0 0 0x4 0
130
131 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
132 0 0 0x4 0
133
134 [12] 1 3 0x8088330 0x3f330 0x20afc .data
135 0 0 0x4 0
136
137 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
138 0 0 0x4 0
139
140 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
141 0 0 0x4 0x4
142
143 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
144 4 0 0x4 0x8
145
146 [16] 8 3 0x80a98f4 0x608f4 0x449c .bss
147 0 0 0x4 0
148
149 [17] 2 0 0 0x608f4 0x9b90 .symtab
150 18 371 0x4 0x10
151
152 [18] 3 0 0 0x6a484 0x8526 .strtab
153 0 0 0x1 0
154
155 [19] 3 0 0 0x729aa 0x93 .shstrtab
156 0 0 0x1 0
157
158 [20] 1 0 0 0x72a3d 0x68b7 .comment
159 0 0 0x1 0
160
161 raid:/nfs/raid/src/dist-18.56/src> dump -h xemacs
162
163 xemacs:
164
165 **** SECTION HEADER TABLE ****
166 [No] Type Flags Addr Offset Size Name
167 Link Info Adralgn Entsize
168
169 [1] 1 2 0x80480d4 0xd4 0x13 .interp
170 0 0 0x1 0
171
172 [2] 5 2 0x80480e8 0xe8 0x388 .hash
173 3 0 0x4 0x4
174
175 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
176 4 1 0x4 0x10
177
178 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
179 0 0 0x1 0
180
181 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
182 3 7 0x4 0x8
183
184 [6] 1 6 0x8049348 0x1348 0x3 .init
185 0 0 0x4 0
186
187 [7] 1 6 0x804934c 0x134c 0x680 .plt
188 0 0 0x4 0x4
189
190 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
191 0 0 0x4 0
192
193 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
194 0 0 0x4 0
195
196 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
197 0 0 0x4 0
198
199 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
200 0 0 0x4 0
201
202 [12] 1 3 0x8088330 0x3f330 0x20afc .data
203 0 0 0x4 0
204
205 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
206 0 0 0x4 0
207
208 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
209 0 0 0x4 0x4
210
211 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
212 4 0 0x4 0x8
213
214 [16] 8 3 0x80c6800 0x7d800 0 .bss
215 0 0 0x4 0
216
217 [17] 2 0 0 0x7d800 0x9b90 .symtab
218 18 371 0x4 0x10
219
220 [18] 3 0 0 0x87390 0x8526 .strtab
221 0 0 0x1 0
222
223 [19] 3 0 0 0x8f8b6 0x93 .shstrtab
224 0 0 0x1 0
225
226 [20] 1 0 0 0x8f949 0x68b7 .comment
227 0 0 0x1 0
228
229 [21] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
230 0 0 0x4 0
231
232 * This is an example of how the file header is changed. "Shoff" is
233 * the section header offset within the file. Since that table is
234 * after the new .data section, it is moved. "Shnum" is the number of
235 * sections, which we increment.
236 *
237 * "Phoff" is the file offset to the program header. "Phentsize" and
238 * "Shentsz" are the program and section header entries sizes respectively.
239 * These can be larger than the apparent struct sizes.
240
241 raid:/nfs/raid/src/dist-18.56/src> dump -f temacs
242
243 temacs:
244
245 **** ELF HEADER ****
246 Class Data Type Machine Version
247 Entry Phoff Shoff Flags Ehsize
248 Phentsize Phnum Shentsz Shnum Shstrndx
249
250 1 1 2 3 1
251 0x80499cc 0x34 0x792f4 0 0x34
252 0x20 5 0x28 21 19
253
254 raid:/nfs/raid/src/dist-18.56/src> dump -f xemacs
255
256 xemacs:
257
258 **** ELF HEADER ****
259 Class Data Type Machine Version
260 Entry Phoff Shoff Flags Ehsize
261 Phentsize Phnum Shentsz Shnum Shstrndx
262
263 1 1 2 3 1
264 0x80499cc 0x34 0x96200 0 0x34
265 0x20 5 0x28 22 19
266
267 * These are the program headers. "Offset" is the file offset to the
268 * segment. "Vaddr" is the memory load address. "Filesz" is the
269 * segment size as it appears in the file, and "Memsz" is the size in
270 * memory. Below, the third segment is the code and the fourth is the
271 * data: the difference between Filesz and Memsz is .bss
272
273 raid:/nfs/raid/src/dist-18.56/src> dump -o temacs
274
275 temacs:
276 ***** PROGRAM EXECUTION HEADER *****
277 Type Offset Vaddr Paddr
278 Filesz Memsz Flags Align
279
280 6 0x34 0x8048034 0
281 0xa0 0xa0 5 0
282
283 3 0xd4 0 0
284 0x13 0 4 0
285
286 1 0x34 0x8048034 0
287 0x3f2f9 0x3f2f9 5 0x1000
288
289 1 0x3f330 0x8088330 0
290 0x215c4 0x25a60 7 0x1000
291
292 2 0x60874 0x80a9874 0
293 0x80 0 7 0
294
295 raid:/nfs/raid/src/dist-18.56/src> dump -o xemacs
296
297 xemacs:
298 ***** PROGRAM EXECUTION HEADER *****
299 Type Offset Vaddr Paddr
300 Filesz Memsz Flags Align
301
302 6 0x34 0x8048034 0
303 0xa0 0xa0 5 0
304
305 3 0xd4 0 0
306 0x13 0 4 0
307
308 1 0x34 0x8048034 0
309 0x3f2f9 0x3f2f9 5 0x1000
310
311 1 0x3f330 0x8088330 0
312 0x3e4d0 0x3e4d0 7 0x1000
313
314 2 0x60874 0x80a9874 0
315 0x80 0 7 0
316
317
318 */
319
320 /* Modified by wtien@urbana.mcd.mot.com of Motorola Inc.
321 *
322 * The above mechanism does not work if the unexeced ELF file is being
323 * re-layout by other applications (such as `strip'). All the applications
324 * that re-layout the internal of ELF will layout all sections in ascending
325 * order of their file offsets. After the re-layout, the data2 section will
326 * still be the LAST section in the section header vector, but its file offset
327 * is now being pushed far away down, and causes part of it not to be mapped
328 * in (ie. not covered by the load segment entry in PHDR vector), therefore
329 * causes the new binary to fail.
330 *
331 * The solution is to modify the unexec algorithm to insert the new data2
332 * section header right before the new bss section header, so their file
333 * offsets will be in the ascending order. Since some of the section's (all
334 * sections AFTER the bss section) indexes are now changed, we also need to
335 * modify some fields to make them point to the right sections. This is done
336 * by macro PATCH_INDEX. All the fields that need to be patched are:
337 *
338 * 1. ELF header e_shstrndx field.
339 * 2. section header sh_link and sh_info field.
340 * 3. symbol table entry st_shndx field.
341 *
342 * The above example now should look like:
343
344 **** SECTION HEADER TABLE ****
345 [No] Type Flags Addr Offset Size Name
346 Link Info Adralgn Entsize
347
348 [1] 1 2 0x80480d4 0xd4 0x13 .interp
349 0 0 0x1 0
350
351 [2] 5 2 0x80480e8 0xe8 0x388 .hash
352 3 0 0x4 0x4
353
354 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
355 4 1 0x4 0x10
356
357 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
358 0 0 0x1 0
359
360 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
361 3 7 0x4 0x8
362
363 [6] 1 6 0x8049348 0x1348 0x3 .init
364 0 0 0x4 0
365
366 [7] 1 6 0x804934c 0x134c 0x680 .plt
367 0 0 0x4 0x4
368
369 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
370 0 0 0x4 0
371
372 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
373 0 0 0x4 0
374
375 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
376 0 0 0x4 0
377
378 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
379 0 0 0x4 0
380
381 [12] 1 3 0x8088330 0x3f330 0x20afc .data
382 0 0 0x4 0
383
384 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
385 0 0 0x4 0
386
387 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
388 0 0 0x4 0x4
389
390 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
391 4 0 0x4 0x8
392
393 [16] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
394 0 0 0x4 0
395
396 [17] 8 3 0x80c6800 0x7d800 0 .bss
397 0 0 0x4 0
398
399 [18] 2 0 0 0x7d800 0x9b90 .symtab
400 19 371 0x4 0x10
401
402 [19] 3 0 0 0x87390 0x8526 .strtab
403 0 0 0x1 0
404
405 [20] 3 0 0 0x8f8b6 0x93 .shstrtab
406 0 0 0x1 0
407
408 [21] 1 0 0 0x8f949 0x68b7 .comment
409 0 0 0x1 0
410
411 */
412
413 /* More mods, by Jack Repenning <jackr@sgi.com>, Fri Aug 11 15:45:52 1995
414
415 Same algorithm as immediately above. However, the detailed
416 calculations of the various locations needed significant
417 overhaul.
418
419 At the point of the old .bss, the file offsets and the memory
420 addresses do distinct, slightly snaky things:
421
422 offset of .bss is meaningless and unpredictable
423 addr of .bss is meaningful
424 alignment of .bss is important to addr, so there may be a small
425 gap in address range before start of bss
426 offset of next section is rounded up modulo 0x1000
427 the hole so-introduced is zero-filled, so it can be mapped in as
428 the first partial-page of bss (the rest of the bss is mapped from
429 /dev/zero)
430 I suppose you could view this not as a hole, but as the beginning
431 of the bss, actually present in the file. But you should not
432 push that worldview too far, as the linker still knows that the
433 "offset" claimed for the bss is unused, and seems not always
434 careful about setting it.
435
436 We are doing all our tricks at this same rather complicated
437 location (isn't life fun?):
438
439 insert a new data section to contain now-initialized old bss and
440 heap
441 define a zero-length bss just so there is one
442
443 The offset of the new data section is dictated by its current
444 address (which, of course, we want also to be its addr): the
445 loader maps in the whole file region containing old data, rodata,
446 got, and new data as a single mapped segment, starting at the
447 address of the first chunk; the rest have to be laid out in the
448 file such that the map into the right spots. That is:
449
450 offset(newdata) ==
451 addrInRunningMemory(newdata)-aIRM(olddata)
452 + offset(oldData)
453
454 This would not necessarily match the oldbss offset, even if it
455 were carefully calculated! We must compute this.
456
457 The linker that built temacs has also already arranged that
458 olddata is properly page-aligned (not necessarily beginning on a
459 page, but rather that a page's worth of the low bits of addr and
460 offset match). We preserve this.
461
462 addr(bss) is alignment-constrained from the end of the new data.
463 Since we base endof(newdata) on sbrk(), we have a page boundary
464 (in both offset and addr) and meet any alignment constraint,
465 needing no alignment adjustment of this location and no
466 mini-hole. Or, if you like, we've allowed sbrk() to "compute"
467 the mini-hole size for us.
468
469 That puts newbss beginning on a page boundary, both in offset and
470 addr. (offset(bss) is still meaningless, but what the heck,
471 we'll fix it up.)
472
473 Since newbss has zero length, and its offset (however
474 meaningless) is page aligned, we place the next section exactly
475 there, with no hole needed to restore page alignment.
476
477 So, the shift for all sections beyond the playing field is:
478
479 new_bss_addr - roundup(old_bss_addr,0x1000)
480
481 */
482 /* Still more mods... Olivier Galibert 19971705
483 - support for .sbss section (automagically changed to data without
484 name change)
485 - support for 64bits ABI (will need a bunch of fixes in the rest
486 of the code before it works
487 */
488
489 #include <sys/types.h>
490 #include <stdio.h>
491 #include <sys/stat.h>
492 #include <memory.h>
493 #include <string.h>
494 #include <errno.h>
495 #include <unistd.h>
496 #include <fcntl.h>
497 #include <elf.h>
498 #include <sym.h> /* for HDRR declaration */
499 #include <sys/mman.h>
500 #include <config.h>
501 #include "lisp.h"
502
503 /* in 64bits mode, use 64bits elf */
504 #ifdef _ABI64
505 typedef Elf64_Shdr l_Elf_Shdr;
506 typedef Elf64_Phdr l_Elf_Phdr;
507 typedef Elf64_Ehdr l_Elf_Ehdr;
508 typedef Elf64_Addr l_Elf_Addr;
509 typedef Elf64_Word l_Elf_Word;
510 typedef Elf64_Off l_Elf_Off;
511 typedef Elf64_Sym l_Elf_Sym;
512 #else
513 typedef Elf32_Shdr l_Elf_Shdr;
514 typedef Elf32_Phdr l_Elf_Phdr;
515 typedef Elf32_Ehdr l_Elf_Ehdr;
516 typedef Elf32_Addr l_Elf_Addr;
517 typedef Elf32_Word l_Elf_Word;
518 typedef Elf32_Off l_Elf_Off;
519 typedef Elf32_Sym l_Elf_Sym;
520 #endif
521
522
523 /* Get the address of a particular section or program header entry,
524 * accounting for the size of the entries.
525 */
526
527 #define OLD_SECTION_H(n) \
528 (*(l_Elf_Shdr *) ((byte *) old_section_h + old_file_h->e_shentsize * (n)))
529 #define NEW_SECTION_H(n) \
530 (*(l_Elf_Shdr *) ((byte *) new_section_h + new_file_h->e_shentsize * (n)))
531 #define OLD_PROGRAM_H(n) \
532 (*(l_Elf_Phdr *) ((byte *) old_program_h + old_file_h->e_phentsize * (n)))
533 #define NEW_PROGRAM_H(n) \
534 (*(l_Elf_Phdr *) ((byte *) new_program_h + new_file_h->e_phentsize * (n)))
535
536 #define PATCH_INDEX(n) \
537 do { \
538 if ((n) >= old_bss_index) \
539 (n)++; } while (0)
540 typedef unsigned char byte;
541
542 /* Round X up to a multiple of Y. */
543
544 static int
545 round_up (int x, int y)
546 {
547 int rem = x % y;
548 if (rem == 0)
549 return x;
550 return x - rem + y;
551 }
552
553 /* Return the index of the section named NAME.
554 SECTION_NAMES, FILE_NAME and FILE_H give information
555 about the file we are looking in.
556
557 If we don't find the section NAME, that is a fatal error
558 if NOERROR is 0; we return -1 if NOERROR is nonzero. */
559
560 static int
561 find_section (char *name,
562 char *section_names,
563 char *file_name,
564 l_Elf_Ehdr *old_file_h,
565 l_Elf_Shdr *old_section_h,
566 int noerror)
567 {
568 int idx;
569
570 for (idx = 1; idx < old_file_h->e_shnum; idx++)
571 {
572 #ifdef DEBUG
573 fprintf (stderr, "Looking for %s - found %s\n", name,
574 section_names + OLD_SECTION_H (idx).sh_name);
575 #endif
576 if (!strcmp (section_names + OLD_SECTION_H (idx).sh_name,
577 name))
578 break;
579 }
580 if (idx == old_file_h->e_shnum)
581 {
582 if (noerror)
583 return -1;
584 else
585 fatal ("Can't find .bss in %s.\n", file_name);
586 }
587
588 return idx;
589 }
590
591 /* ****************************************************************
592 * unexec
593 *
594 * driving logic.
595 *
596 * In ELF, this works by replacing the old .bss section with a new
597 * .data section, and inserting an empty .bss immediately afterwards.
598 *
599 */
600 int
601 unexec (char *new_name,
602 char *old_name,
603 uintptr_t data_start,
604 uintptr_t bss_start,
605 uintptr_t entry_address)
606 {
607 extern uintptr_t bss_end;
608 int new_file, old_file, new_file_size;
609
610 /* Pointers to the base of the image of the two files. */
611 caddr_t old_base, new_base;
612
613 /* Pointers to the file, program and section headers for the old and new
614 files. */
615 l_Elf_Ehdr *old_file_h, *new_file_h;
616 l_Elf_Phdr *old_program_h, *new_program_h;
617 l_Elf_Shdr *old_section_h, *new_section_h;
618
619 /* Point to the section name table in the old file. */
620 char *old_section_names;
621
622 l_Elf_Addr old_bss_addr, new_bss_addr;
623 l_Elf_Addr old_base_addr;
624 l_Elf_Word old_bss_size, new_data2_size;
625 l_Elf_Off new_data2_offset, new_base_offset;
626 l_Elf_Addr new_data2_addr;
627 l_Elf_Addr new_offsets_shift;
628
629 int n, nn, old_bss_index, old_data_index;
630 int old_mdebug_index, old_sbss_index;
631 struct stat stat_buf;
632
633 /* Open the old file & map it into the address space. */
634
635 old_file = open (old_name, O_RDONLY);
636
637 if (old_file < 0)
638 fatal ("Can't open %s for reading: errno %d\n", old_name, errno);
639
640 if (fstat (old_file, &stat_buf) == -1)
641 fatal ("Can't fstat(%s): errno %d\n", old_name, errno);
642
643 old_base = mmap (0, stat_buf.st_size, PROT_READ, MAP_SHARED, old_file, 0);
644
645 if (old_base == (caddr_t) -1)
646 fatal ("Can't mmap(%s): errno %d\n", old_name, errno);
647
648 #ifdef DEBUG
649 fprintf (stderr, "mmap(%s, %x) -> %x\n", old_name, stat_buf.st_size,
650 old_base);
651 #endif
652
653 /* Get pointers to headers & section names. */
654
655 old_file_h = (l_Elf_Ehdr *) old_base;
656 old_program_h = (l_Elf_Phdr *) ((byte *) old_base + old_file_h->e_phoff);
657 old_section_h = (l_Elf_Shdr *) ((byte *) old_base + old_file_h->e_shoff);
658 old_section_names
659 = (char *) old_base + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset;
660
661 /* Find the mdebug section, if any. */
662
663 old_mdebug_index = find_section (".mdebug", old_section_names,
664 old_name, old_file_h, old_section_h, 1);
665
666 /* Find the .sbss section, if any. */
667
668 old_sbss_index = find_section (".sbss", old_section_names,
669 old_name, old_file_h, old_section_h, 1);
670
671 if (old_sbss_index != -1 && (OLD_SECTION_H (old_sbss_index).sh_type == SHT_PROGBITS))
672 old_sbss_index = -1;
673
674 /* Find the old .bss section. */
675
676 old_bss_index = find_section (".bss", old_section_names,
677 old_name, old_file_h, old_section_h, 0);
678
679 /* Find the old .data section. Figure out parameters of
680 the new data2 and bss sections. */
681
682 old_data_index = find_section (".data", old_section_names,
683 old_name, old_file_h, old_section_h, 0);
684
685 old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr;
686 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size;
687 old_base_addr = old_sbss_index == -1 ? old_bss_addr : OLD_SECTION_H (old_sbss_index).sh_addr;
688 #if defined(emacs) || !defined(DEBUG)
689 bss_end = (uintptr_t) sbrk (0);
690 new_bss_addr = (l_Elf_Addr) bss_end;
691 #else
692 new_bss_addr = old_bss_addr + old_bss_size + 0x1234;
693 #endif
694 new_data2_addr = old_bss_addr;
695 new_data2_size = new_bss_addr - old_bss_addr;
696 new_data2_offset = OLD_SECTION_H (old_data_index).sh_offset +
697 (new_data2_addr - OLD_SECTION_H (old_data_index).sh_addr);
698 new_base_offset = OLD_SECTION_H (old_data_index).sh_offset +
699 (old_base_addr - OLD_SECTION_H (old_data_index).sh_addr);
700 new_offsets_shift = new_bss_addr -
701 ((old_base_addr & ~0xfff) + ((old_base_addr & 0xfff) ? 0x1000 : 0));
702
703 #ifdef DEBUG
704 fprintf (stderr, "old_bss_index %d\n", old_bss_index);
705 fprintf (stderr, "old_bss_addr %x\n", old_bss_addr);
706 fprintf (stderr, "old_bss_size %x\n", old_bss_size);
707 fprintf (stderr, "old_base_addr %x\n", old_base_addr);
708 fprintf (stderr, "new_bss_addr %x\n", new_bss_addr);
709 fprintf (stderr, "new_data2_addr %x\n", new_data2_addr);
710 fprintf (stderr, "new_data2_size %x\n", new_data2_size);
711 fprintf (stderr, "new_data2_offset %x\n", new_data2_offset);
712 fprintf (stderr, "new_offsets_shift %x\n", new_offsets_shift);
713 #endif
714
715 if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size)
716 fatal (".bss shrank when undumping???\n");
717
718 /* Set the output file to the right size and mmap it. Set
719 pointers to various interesting objects. stat_buf still has
720 old_file data. */
721
722 new_file = open (new_name, O_RDWR | O_CREAT, 0666);
723 if (new_file < 0)
724 fatal ("Can't creat (%s): errno %d\n", new_name, errno);
725
726 new_file_size = stat_buf.st_size /* old file size */
727 + old_file_h->e_shentsize /* one new section header */
728 + new_offsets_shift; /* trailing section shift */
729
730 if (ftruncate (new_file, new_file_size))
731 fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
732
733 new_base = mmap (0, new_file_size, PROT_READ | PROT_WRITE, MAP_SHARED,
734 new_file, 0);
735
736 if (new_base == (caddr_t) -1)
737 fatal ("Can't mmap (%s): errno %d\n", new_name, errno);
738
739 new_file_h = (l_Elf_Ehdr *) new_base;
740 new_program_h = (l_Elf_Phdr *) ((byte *) new_base + old_file_h->e_phoff);
741 new_section_h
742 = (l_Elf_Shdr *) ((byte *) new_base + old_file_h->e_shoff
743 + new_offsets_shift);
744
745 /* Make our new file, program and section headers as copies of the
746 originals. */
747
748 memcpy (new_file_h, old_file_h, old_file_h->e_ehsize);
749 memcpy (new_program_h, old_program_h,
750 old_file_h->e_phnum * old_file_h->e_phentsize);
751
752 /* Modify the e_shstrndx if necessary. */
753 PATCH_INDEX (new_file_h->e_shstrndx);
754
755 /* Fix up file header. We'll add one section. Section header is
756 further away now. */
757
758 new_file_h->e_shoff += new_offsets_shift;
759 new_file_h->e_shnum += 1;
760
761
762 #ifdef DEBUG
763 fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff);
764 fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum);
765 fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff);
766 fprintf (stderr, "New section count %d\n", new_file_h->e_shnum);
767 #endif
768
769 /* Fix up a new program header. Extend the writable data segment so
770 that the bss area is covered too. Find that segment by looking
771 for a segment that ends just before the .bss area. Make sure
772 that no segments are above the new .data2. Put a loop at the end
773 to adjust the offset and address of any segment that is above
774 data2, just in case we decide to allow this later. */
775
776 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
777 {
778 /* Compute maximum of all requirements for alignment of section. */
779 int alignment = (NEW_PROGRAM_H (n)).p_align;
780 if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment)
781 alignment = OLD_SECTION_H (old_bss_index).sh_addralign;
782
783 /* Supposedly this condition is okay for the SGI. */
784 #if 0
785 if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz > old_base_addr)
786 fatal ("Program segment above .bss in %s\n", old_name);
787 #endif
788
789 if (NEW_PROGRAM_H (n).p_type == PT_LOAD
790 && (round_up ((NEW_PROGRAM_H (n)).p_vaddr
791 + (NEW_PROGRAM_H (n)).p_filesz,
792 alignment)
793 == round_up (old_base_addr, alignment)))
794 break;
795 }
796 if (n < 0)
797 fatal ("Couldn't find segment next to %s in %s\n",
798 old_sbss_index == -1 ? ".sbss" : ".bss", old_name);
799
800 NEW_PROGRAM_H (n).p_filesz += new_offsets_shift;
801 NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz;
802
803 #if 1 /* Maybe allow section after data2 - does this ever happen? */
804 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
805 {
806 if (NEW_PROGRAM_H (n).p_vaddr
807 && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr)
808 NEW_PROGRAM_H (n).p_vaddr += new_offsets_shift - old_bss_size;
809
810 if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset)
811 NEW_PROGRAM_H (n).p_offset += new_offsets_shift;
812 }
813 #endif
814
815 /* Fix up section headers based on new .data2 section. Any section
816 whose offset or virtual address is after the new .data2 section
817 gets its value adjusted. .bss size becomes zero and new address
818 is set. data2 section header gets added by copying the existing
819 .data header and modifying the offset, address and size. */
820 for (old_data_index = 1; old_data_index < old_file_h->e_shnum;
821 old_data_index++)
822 if (!strcmp (old_section_names + OLD_SECTION_H (old_data_index).sh_name,
823 ".data"))
824 break;
825 if (old_data_index == old_file_h->e_shnum)
826 fatal ("Can't find .data in %s.\n", old_name);
827
828 /* Walk through all section headers, insert the new data2 section right
829 before the new bss section. */
830 for (n = 1, nn = 1; n < old_file_h->e_shnum; n++, nn++)
831 {
832 caddr_t src;
833
834 /* XEmacs change: */
835 if (n < old_bss_index)
836 {
837 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
838 old_file_h->e_shentsize);
839
840 }
841 else if (n == old_bss_index)
842 {
843
844 /* If it is bss section, insert the new data2 section before it. */
845 /* Steal the data section header for this data2 section. */
846 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index),
847 new_file_h->e_shentsize);
848
849 NEW_SECTION_H (nn).sh_addr = new_data2_addr;
850 NEW_SECTION_H (nn).sh_offset = new_data2_offset;
851 NEW_SECTION_H (nn).sh_size = new_data2_size;
852 /* Use the bss section's alignment. This will assure that the
853 new data2 section always be placed in the same spot as the old
854 bss section by any other application. */
855 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign;
856
857 /* Now copy over what we have in the memory now. */
858 memcpy (NEW_SECTION_H (nn).sh_offset + new_base,
859 (caddr_t) OLD_SECTION_H (n).sh_addr,
860 new_data2_size);
861 nn++;
862 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
863 old_file_h->e_shentsize);
864
865 /* The new bss section's size is zero, and its file offset and virtual
866 address should be off by NEW_OFFSETS_SHIFT. */
867 NEW_SECTION_H (nn).sh_offset += new_offsets_shift;
868 NEW_SECTION_H (nn).sh_addr = new_bss_addr;
869 /* Let the new bss section address alignment be the same as the
870 section address alignment followed the old bss section, so
871 this section will be placed in exactly the same place. */
872 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign;
873 NEW_SECTION_H (nn).sh_size = 0;
874 }
875 else /* n > old_bss_index */
876 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
877 old_file_h->e_shentsize);
878
879 /* Any section that was original placed AFTER the bss
880 section must now be adjusted by NEW_OFFSETS_SHIFT. */
881
882 if (NEW_SECTION_H (nn).sh_offset >= new_base_offset)
883 NEW_SECTION_H (nn).sh_offset += new_offsets_shift;
884
885 /* If any section hdr refers to the section after the new .data
886 section, make it refer to next one because we have inserted
887 a new section in between. */
888
889 PATCH_INDEX (NEW_SECTION_H (nn).sh_link);
890 /* For symbol tables, info is a symbol table index,
891 so don't change it. */
892 if (NEW_SECTION_H (nn).sh_type != SHT_SYMTAB
893 && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM)
894 PATCH_INDEX (NEW_SECTION_H (nn).sh_info);
895
896 /* Fix the type and alignment for the .sbss section */
897 if ((old_sbss_index != -1) && !strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".sbss"))
898 {
899 NEW_SECTION_H (nn).sh_type = SHT_PROGBITS;
900 NEW_SECTION_H (nn).sh_offset = round_up (NEW_SECTION_H (nn).sh_offset,
901 NEW_SECTION_H (nn).sh_addralign);
902 }
903
904 /* Now, start to copy the content of sections. */
905 if (NEW_SECTION_H (nn).sh_type == SHT_NULL
906 || NEW_SECTION_H (nn).sh_type == SHT_NOBITS)
907 continue;
908
909 /* Write out the sections. .data, .data1 and .sbss (and data2, called
910 ".data" in the strings table) get copied from the current process
911 instead of the old file. */
912 if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".data")
913 || !strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".data1")
914 || !strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".got")
915 || !strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".sbss"))
916 src = (caddr_t) OLD_SECTION_H (n).sh_addr;
917 else
918 src = old_base + OLD_SECTION_H (n).sh_offset;
919
920 memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src,
921 NEW_SECTION_H (nn).sh_size);
922
923 /* Adjust the HDRR offsets in .mdebug and copy the
924 line data if it's in its usual 'hole' in the object.
925 Makes the new file debuggable with dbx.
926 patches up two problems: the absolute file offsets
927 in the HDRR record of .mdebug (see /usr/include/syms.h), and
928 the ld bug that gets the line table in a hole in the
929 elf file rather than in the .mdebug section proper.
930 David Anderson. davea@sgi.com Jan 16,1994. */
931 if (n == old_mdebug_index)
932 {
933 #define MDEBUGADJUST(__ct,__fileaddr) \
934 if (n_phdrr->__ct > 0) \
935 { \
936 n_phdrr->__fileaddr += movement; \
937 }
938
939 HDRR * o_phdrr = (HDRR *)((byte *)old_base + OLD_SECTION_H (n).sh_offset);
940 HDRR * n_phdrr = (HDRR *)((byte *)new_base + NEW_SECTION_H (nn).sh_offset);
941 unsigned movement = new_offsets_shift;
942
943 MDEBUGADJUST (idnMax, cbDnOffset);
944 MDEBUGADJUST (ipdMax, cbPdOffset);
945 MDEBUGADJUST (isymMax, cbSymOffset);
946 MDEBUGADJUST (ioptMax, cbOptOffset);
947 MDEBUGADJUST (iauxMax, cbAuxOffset);
948 MDEBUGADJUST (issMax, cbSsOffset);
949 MDEBUGADJUST (issExtMax, cbSsExtOffset);
950 MDEBUGADJUST (ifdMax, cbFdOffset);
951 MDEBUGADJUST (crfd, cbRfdOffset);
952 MDEBUGADJUST (iextMax, cbExtOffset);
953 /* The Line Section, being possible off in a hole of the object,
954 requires special handling. */
955 if (n_phdrr->cbLine > 0)
956 {
957 if (o_phdrr->cbLineOffset > (OLD_SECTION_H (n).sh_offset
958 + OLD_SECTION_H (n).sh_size))
959 {
960 /* line data is in a hole in elf. do special copy and adjust
961 for this ld mistake.
962 */
963 n_phdrr->cbLineOffset += movement;
964
965 memcpy (n_phdrr->cbLineOffset + new_base,
966 o_phdrr->cbLineOffset + old_base, n_phdrr->cbLine);
967 }
968 else
969 {
970 /* somehow line data is in .mdebug as it is supposed to be. */
971 MDEBUGADJUST (cbLine, cbLineOffset);
972 }
973 }
974 }
975
976 /* If it is the symbol table, its st_shndx field needs to be patched. */
977 if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB
978 || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM)
979 {
980 l_Elf_Shdr *spt = &NEW_SECTION_H (nn);
981 unsigned int num = spt->sh_size / spt->sh_entsize;
982 l_Elf_Sym * sym = (l_Elf_Sym *) (NEW_SECTION_H (nn).sh_offset
983 + new_base);
984 for (; num--; sym++)
985 {
986 if (sym->st_shndx == SHN_UNDEF
987 || sym->st_shndx == SHN_ABS
988 || sym->st_shndx == SHN_COMMON)
989 continue;
990
991 PATCH_INDEX (sym->st_shndx);
992 }
993 }
994 }
995
996 /* Close the files and make the new file executable. */
997
998 if (close (old_file))
999 fatal ("Can't close (%s): errno %d\n", old_name, errno);
1000
1001 if (close (new_file))
1002 fatal ("Can't close (%s): errno %d\n", new_name, errno);
1003
1004 if (stat (new_name, &stat_buf) == -1)
1005 fatal ("Can't stat (%s): errno %d\n", new_name, errno);
1006
1007 n = umask (777);
1008 umask (n);
1009 stat_buf.st_mode |= 0111 & ~n;
1010 if (chmod (new_name, stat_buf.st_mode) == -1)
1011 fatal ("Can't chmod (%s): errno %d\n", new_name, errno);
1012
1013 return 0;
1014 }