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[emacs.git] / src / unexsgi.c
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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 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, a_name, data_start, bss_start, entry_address)
37 * char *new_name, *a_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 a_name is non-NULL, the symbol table will be taken from the given file.
43 * On some machines, an existing a_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 #include <elf.h>
424 #include <syms.h> /* for HDRR declaration */
425 #include <sys/mman.h>
426
427 #ifndef emacs
428 #define fatal(a, b, c) fprintf(stderr, a, b, c), exit(1)
429 #else
430 extern void fatal(char *, ...);
431 #endif
432
433 /* Get the address of a particular section or program header entry,
434 * accounting for the size of the entries.
435 */
436
437 #define OLD_SECTION_H(n) \
438 (*(Elf32_Shdr *) ((byte *) old_section_h + old_file_h->e_shentsize * (n)))
439 #define NEW_SECTION_H(n) \
440 (*(Elf32_Shdr *) ((byte *) new_section_h + new_file_h->e_shentsize * (n)))
441 #define OLD_PROGRAM_H(n) \
442 (*(Elf32_Phdr *) ((byte *) old_program_h + old_file_h->e_phentsize * (n)))
443 #define NEW_PROGRAM_H(n) \
444 (*(Elf32_Phdr *) ((byte *) new_program_h + new_file_h->e_phentsize * (n)))
445
446 #define PATCH_INDEX(n) \
447 do { \
448 if ((n) >= old_bss_index) \
449 (n)++; } while (0)
450 typedef unsigned char byte;
451
452 /* Round X up to a multiple of Y. */
453
454 int
455 round_up (x, y)
456 int x, y;
457 {
458 int rem = x % y;
459 if (rem == 0)
460 return x;
461 return x - rem + y;
462 }
463
464 /* Return the index of the section named NAME.
465 SECTION_NAMES, FILE_NAME and FILE_H give information
466 about the file we are looking in.
467
468 If we don't find the section NAME, that is a fatal error
469 if NOERROR is 0; we return -1 if NOERROR is nonzero. */
470
471 static int
472 find_section (name, section_names, file_name, old_file_h, old_section_h, noerror)
473 char *name;
474 char *section_names;
475 char *file_name;
476 Elf32_Ehdr *old_file_h;
477 Elf32_Shdr *old_section_h;
478 int noerror;
479 {
480 int idx;
481
482 for (idx = 1; idx < old_file_h->e_shnum; idx++)
483 {
484 #ifdef DEBUG
485 fprintf (stderr, "Looking for %s - found %s\n", name,
486 section_names + OLD_SECTION_H (idx).sh_name);
487 #endif
488 if (!strcmp (section_names + OLD_SECTION_H (idx).sh_name,
489 name))
490 break;
491 }
492 if (idx == old_file_h->e_shnum)
493 {
494 if (noerror)
495 return -1;
496 else
497 fatal ("Can't find .bss in %s.\n", file_name, 0);
498 }
499
500 return idx;
501 }
502
503 /* ****************************************************************
504 * unexec
505 *
506 * driving logic.
507 *
508 * In ELF, this works by replacing the old .bss section with a new
509 * .data section, and inserting an empty .bss immediately afterwards.
510 *
511 */
512 void
513 unexec (new_name, old_name, data_start, bss_start, entry_address)
514 char *new_name, *old_name;
515 unsigned data_start, bss_start, entry_address;
516 {
517 extern unsigned int bss_end;
518 int new_file, old_file, new_file_size;
519
520 /* Pointers to the base of the image of the two files. */
521 caddr_t old_base, new_base;
522
523 /* Pointers to the file, program and section headers for the old and new
524 files. */
525 Elf32_Ehdr *old_file_h, *new_file_h;
526 Elf32_Phdr *old_program_h, *new_program_h;
527 Elf32_Shdr *old_section_h, *new_section_h;
528
529 /* Point to the section name table in the old file. */
530 char *old_section_names;
531
532 Elf32_Addr old_bss_addr, new_bss_addr;
533 Elf32_Word old_bss_size, new_data2_size;
534 Elf32_Off new_data2_offset;
535 Elf32_Addr new_data2_addr;
536 Elf32_Addr new_offsets_shift;
537
538 int n, nn, old_bss_index, old_data_index, new_data2_index;
539 int old_mdebug_index;
540 struct stat stat_buf;
541
542 /* Open the old file & map it into the address space. */
543
544 old_file = open (old_name, O_RDONLY);
545
546 if (old_file < 0)
547 fatal ("Can't open %s for reading: errno %d\n", old_name, errno);
548
549 if (fstat (old_file, &stat_buf) == -1)
550 fatal ("Can't fstat(%s): errno %d\n", old_name, errno);
551
552 old_base = mmap (0, stat_buf.st_size, PROT_READ, MAP_SHARED, old_file, 0);
553
554 if (old_base == (caddr_t) -1)
555 fatal ("Can't mmap(%s): errno %d\n", old_name, errno);
556
557 #ifdef DEBUG
558 fprintf (stderr, "mmap(%s, %x) -> %x\n", old_name, stat_buf.st_size,
559 old_base);
560 #endif
561
562 /* Get pointers to headers & section names. */
563
564 old_file_h = (Elf32_Ehdr *) old_base;
565 old_program_h = (Elf32_Phdr *) ((byte *) old_base + old_file_h->e_phoff);
566 old_section_h = (Elf32_Shdr *) ((byte *) old_base + old_file_h->e_shoff);
567 old_section_names
568 = (char *) old_base + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset;
569
570 /* Find the mdebug section, if any. */
571
572 old_mdebug_index = find_section (".mdebug", old_section_names,
573 old_name, old_file_h, old_section_h, 1);
574
575 /* Find the old .bss section. */
576
577 old_bss_index = find_section (".bss", old_section_names,
578 old_name, old_file_h, old_section_h, 0);
579
580 /* Find the old .data section. Figure out parameters of
581 the new data2 and bss sections. */
582
583 old_data_index = find_section (".data", old_section_names,
584 old_name, old_file_h, old_section_h, 0);
585
586 old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr;
587 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size;
588 #if defined(emacs) || !defined(DEBUG)
589 bss_end = (unsigned int) sbrk (0);
590 new_bss_addr = (Elf32_Addr) bss_end;
591 #else
592 new_bss_addr = old_bss_addr + old_bss_size + 0x1234;
593 #endif
594 new_data2_addr = old_bss_addr;
595 new_data2_size = new_bss_addr - old_bss_addr;
596 new_data2_offset = OLD_SECTION_H (old_data_index).sh_offset +
597 (new_data2_addr - OLD_SECTION_H (old_data_index).sh_addr);
598 new_offsets_shift = new_bss_addr -
599 ((old_bss_addr & ~0xfff) + ((old_bss_addr & 0xfff) ? 0x1000 : 0));
600
601 #ifdef DEBUG
602 fprintf (stderr, "old_bss_index %d\n", old_bss_index);
603 fprintf (stderr, "old_bss_addr %x\n", old_bss_addr);
604 fprintf (stderr, "old_bss_size %x\n", old_bss_size);
605 fprintf (stderr, "new_bss_addr %x\n", new_bss_addr);
606 fprintf (stderr, "new_data2_addr %x\n", new_data2_addr);
607 fprintf (stderr, "new_data2_size %x\n", new_data2_size);
608 fprintf (stderr, "new_data2_offset %x\n", new_data2_offset);
609 fprintf (stderr, "new_offsets_shift %x\n", new_offsets_shift);
610 #endif
611
612 if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size)
613 fatal (".bss shrank when undumping???\n", 0, 0);
614
615 /* Set the output file to the right size and mmap it. Set
616 pointers to various interesting objects. stat_buf still has
617 old_file data. */
618
619 new_file = open (new_name, O_RDWR | O_CREAT, 0666);
620 if (new_file < 0)
621 fatal ("Can't creat (%s): errno %d\n", new_name, errno);
622
623 new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_offsets_shift;
624
625 if (ftruncate (new_file, new_file_size))
626 fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
627
628 new_base = mmap (0, new_file_size, PROT_READ | PROT_WRITE, MAP_SHARED,
629 new_file, 0);
630
631 if (new_base == (caddr_t) -1)
632 fatal ("Can't mmap (%s): errno %d\n", new_name, errno);
633
634 new_file_h = (Elf32_Ehdr *) new_base;
635 new_program_h = (Elf32_Phdr *) ((byte *) new_base + old_file_h->e_phoff);
636 new_section_h
637 = (Elf32_Shdr *) ((byte *) new_base + old_file_h->e_shoff
638 + new_offsets_shift);
639
640 /* Make our new file, program and section headers as copies of the
641 originals. */
642
643 memcpy (new_file_h, old_file_h, old_file_h->e_ehsize);
644 memcpy (new_program_h, old_program_h,
645 old_file_h->e_phnum * old_file_h->e_phentsize);
646
647 /* Modify the e_shstrndx if necessary. */
648 PATCH_INDEX (new_file_h->e_shstrndx);
649
650 /* Fix up file header. We'll add one section. Section header is
651 further away now. */
652
653 new_file_h->e_shoff += new_offsets_shift;
654 new_file_h->e_shnum += 1;
655
656 #ifdef DEBUG
657 fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff);
658 fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum);
659 fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff);
660 fprintf (stderr, "New section count %d\n", new_file_h->e_shnum);
661 #endif
662
663 /* Fix up a new program header. Extend the writable data segment so
664 that the bss area is covered too. Find that segment by looking
665 for a segment that ends just before the .bss area. Make sure
666 that no segments are above the new .data2. Put a loop at the end
667 to adjust the offset and address of any segment that is above
668 data2, just in case we decide to allow this later. */
669
670 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
671 {
672 /* Compute maximum of all requirements for alignment of section. */
673 int alignment = (NEW_PROGRAM_H (n)).p_align;
674 if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment)
675 alignment = OLD_SECTION_H (old_bss_index).sh_addralign;
676
677 /* Supposedly this condition is okay for the SGI. */
678 #if 0
679 if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz > old_bss_addr)
680 fatal ("Program segment above .bss in %s\n", old_name, 0);
681 #endif
682
683 if (NEW_PROGRAM_H (n).p_type == PT_LOAD
684 && (round_up ((NEW_PROGRAM_H (n)).p_vaddr
685 + (NEW_PROGRAM_H (n)).p_filesz,
686 alignment)
687 == round_up (old_bss_addr, alignment)))
688 break;
689 }
690 if (n < 0)
691 fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0);
692
693 NEW_PROGRAM_H (n).p_filesz += new_offsets_shift;
694 NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz;
695
696 #if 1 /* Maybe allow section after data2 - does this ever happen? */
697 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
698 {
699 if (NEW_PROGRAM_H (n).p_vaddr
700 && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr)
701 NEW_PROGRAM_H (n).p_vaddr += new_offsets_shift - old_bss_size;
702
703 if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset)
704 NEW_PROGRAM_H (n).p_offset += new_offsets_shift;
705 }
706 #endif
707
708 /* Fix up section headers based on new .data2 section. Any section
709 whose offset or virtual address is after the new .data2 section
710 gets its value adjusted. .bss size becomes zero and new address
711 is set. data2 section header gets added by copying the existing
712 .data header and modifying the offset, address and size. */
713 for (old_data_index = 1; old_data_index < old_file_h->e_shnum;
714 old_data_index++)
715 if (!strcmp (old_section_names + OLD_SECTION_H (old_data_index).sh_name,
716 ".data"))
717 break;
718 if (old_data_index == old_file_h->e_shnum)
719 fatal ("Can't find .data in %s.\n", old_name, 0);
720
721 /* Walk through all section headers, insert the new data2 section right
722 before the new bss section. */
723 for (n = 1, nn = 1; n < old_file_h->e_shnum; n++, nn++)
724 {
725 caddr_t src;
726
727 /* If it is bss section, insert the new data2 section before it. */
728 if (n == old_bss_index)
729 {
730 /* Steal the data section header for this data2 section. */
731 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index),
732 new_file_h->e_shentsize);
733
734 NEW_SECTION_H (nn).sh_addr = new_data2_addr;
735 NEW_SECTION_H (nn).sh_offset = new_data2_offset;
736 NEW_SECTION_H (nn).sh_size = new_data2_size;
737 /* Use the bss section's alignment. This will assure that the
738 new data2 section always be placed in the same spot as the old
739 bss section by any other application. */
740 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign;
741
742 /* Now copy over what we have in the memory now. */
743 memcpy (NEW_SECTION_H (nn).sh_offset + new_base,
744 (caddr_t) OLD_SECTION_H (n).sh_addr,
745 new_data2_size);
746 nn++;
747 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
748 old_file_h->e_shentsize);
749
750 /* The new bss section's size is zero, and its file offset and virtual
751 address should be off by NEW_OFFSETS_SHIFT. */
752 NEW_SECTION_H (nn).sh_offset += new_offsets_shift;
753 NEW_SECTION_H (nn).sh_addr = new_bss_addr;
754 /* Let the new bss section address alignment be the same as the
755 section address alignment followed the old bss section, so
756 this section will be placed in exactly the same place. */
757 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign;
758 NEW_SECTION_H (nn).sh_size = 0;
759 }
760 else
761 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
762 old_file_h->e_shentsize);
763
764 /* Any section that was original placed AFTER the bss
765 section must now be adjusted by NEW_OFFSETS_SHIFT. */
766
767 if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset)
768 NEW_SECTION_H (nn).sh_offset += new_offsets_shift;
769
770 /* If any section hdr refers to the section after the new .data
771 section, make it refer to next one because we have inserted
772 a new section in between. */
773
774 PATCH_INDEX (NEW_SECTION_H (nn).sh_link);
775 /* For symbol tables, info is a symbol table index,
776 so don't change it. */
777 if (NEW_SECTION_H (nn).sh_type != SHT_SYMTAB
778 && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM)
779 PATCH_INDEX (NEW_SECTION_H (nn).sh_info);
780
781 /* Now, start to copy the content of sections. */
782 if (NEW_SECTION_H (nn).sh_type == SHT_NULL
783 || NEW_SECTION_H (nn).sh_type == SHT_NOBITS)
784 continue;
785
786 /* Write out the sections. .data and .data1 (and data2, called
787 ".data" in the strings table) get copied from the current process
788 instead of the old file. */
789 if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data")
790 || !strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data1")
791 || !strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".got"))
792 src = (caddr_t) OLD_SECTION_H (n).sh_addr;
793 else
794 src = old_base + OLD_SECTION_H (n).sh_offset;
795
796 memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src,
797 NEW_SECTION_H (nn).sh_size);
798
799 /* Adjust the HDRR offsets in .mdebug and copy the
800 line data if it's in its usual 'hole' in the object.
801 Makes the new file debuggable with dbx.
802 patches up two problems: the absolute file offsets
803 in the HDRR record of .mdebug (see /usr/include/syms.h), and
804 the ld bug that gets the line table in a hole in the
805 elf file rather than in the .mdebug section proper.
806 David Anderson. davea@sgi.com Jan 16,1994. */
807 if (n == old_mdebug_index)
808 {
809 #define MDEBUGADJUST(__ct,__fileaddr) \
810 if (n_phdrr->__ct > 0) \
811 { \
812 n_phdrr->__fileaddr += movement; \
813 }
814
815 HDRR * o_phdrr = (HDRR *)((byte *)old_base + OLD_SECTION_H (n).sh_offset);
816 HDRR * n_phdrr = (HDRR *)((byte *)new_base + NEW_SECTION_H (nn).sh_offset);
817 unsigned movement = new_offsets_shift;
818
819 MDEBUGADJUST (idnMax, cbDnOffset);
820 MDEBUGADJUST (ipdMax, cbPdOffset);
821 MDEBUGADJUST (isymMax, cbSymOffset);
822 MDEBUGADJUST (ioptMax, cbOptOffset);
823 MDEBUGADJUST (iauxMax, cbAuxOffset);
824 MDEBUGADJUST (issMax, cbSsOffset);
825 MDEBUGADJUST (issExtMax, cbSsExtOffset);
826 MDEBUGADJUST (ifdMax, cbFdOffset);
827 MDEBUGADJUST (crfd, cbRfdOffset);
828 MDEBUGADJUST (iextMax, cbExtOffset);
829 /* The Line Section, being possible off in a hole of the object,
830 requires special handling. */
831 if (n_phdrr->cbLine > 0)
832 {
833 if (o_phdrr->cbLineOffset > (OLD_SECTION_H (n).sh_offset
834 + OLD_SECTION_H (n).sh_size))
835 {
836 /* line data is in a hole in elf. do special copy and adjust
837 for this ld mistake.
838 */
839 n_phdrr->cbLineOffset += movement;
840
841 memcpy (n_phdrr->cbLineOffset + new_base,
842 o_phdrr->cbLineOffset + old_base, n_phdrr->cbLine);
843 }
844 else
845 {
846 /* somehow line data is in .mdebug as it is supposed to be. */
847 MDEBUGADJUST (cbLine, cbLineOffset);
848 }
849 }
850 }
851
852 /* If it is the symbol table, its st_shndx field needs to be patched. */
853 if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB
854 || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM)
855 {
856 Elf32_Shdr *spt = &NEW_SECTION_H (nn);
857 unsigned int num = spt->sh_size / spt->sh_entsize;
858 Elf32_Sym * sym = (Elf32_Sym *) (NEW_SECTION_H (nn).sh_offset
859 + new_base);
860 for (; num--; sym++)
861 {
862 if (sym->st_shndx == SHN_UNDEF
863 || sym->st_shndx == SHN_ABS
864 || sym->st_shndx == SHN_COMMON)
865 continue;
866
867 PATCH_INDEX (sym->st_shndx);
868 }
869 }
870 }
871
872 /* Close the files and make the new file executable. */
873
874 if (close (old_file))
875 fatal ("Can't close (%s): errno %d\n", old_name, errno);
876
877 if (close (new_file))
878 fatal ("Can't close (%s): errno %d\n", new_name, errno);
879
880 if (stat (new_name, &stat_buf) == -1)
881 fatal ("Can't stat (%s): errno %d\n", new_name, errno);
882
883 n = umask (777);
884 umask (n);
885 stat_buf.st_mode |= 0111 & ~n;
886 if (chmod (new_name, stat_buf.st_mode) == -1)
887 fatal ("Can't chmod (%s): errno %d\n", new_name, errno);
888 }
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