]> code.delx.au - gnu-emacs/blob - src/unexelf.c
Eliminate local var bss_end.
[gnu-emacs] / src / unexelf.c
1 /* Copyright (C) 1985, 1986, 1987, 1988, 1990, 1992
2 Free Software Foundation, Inc.
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2, or (at your option)
7 any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17
18 In other words, you are welcome to use, share and improve this program.
19 You are forbidden to forbid anyone else to use, share and improve
20 what you give them. Help stamp out software-hoarding! */
21
22
23 /*
24 * unexec.c - Convert a running program into an a.out file.
25 *
26 * Author: Spencer W. Thomas
27 * Computer Science Dept.
28 * University of Utah
29 * Date: Tue Mar 2 1982
30 * Modified heavily since then.
31 *
32 * Synopsis:
33 * unexec (new_name, a_name, data_start, bss_start, entry_address)
34 * char *new_name, *a_name;
35 * unsigned data_start, bss_start, entry_address;
36 *
37 * Takes a snapshot of the program and makes an a.out format file in the
38 * file named by the string argument new_name.
39 * If a_name is non-NULL, the symbol table will be taken from the given file.
40 * On some machines, an existing a_name file is required.
41 *
42 * The boundaries within the a.out file may be adjusted with the data_start
43 * and bss_start arguments. Either or both may be given as 0 for defaults.
44 *
45 * Data_start gives the boundary between the text segment and the data
46 * segment of the program. The text segment can contain shared, read-only
47 * program code and literal data, while the data segment is always unshared
48 * and unprotected. Data_start gives the lowest unprotected address.
49 * The value you specify may be rounded down to a suitable boundary
50 * as required by the machine you are using.
51 *
52 * Specifying zero for data_start means the boundary between text and data
53 * should not be the same as when the program was loaded.
54 * If NO_REMAP is defined, the argument data_start is ignored and the
55 * segment boundaries are never changed.
56 *
57 * Bss_start indicates how much of the data segment is to be saved in the
58 * a.out file and restored when the program is executed. It gives the lowest
59 * unsaved address, and is rounded up to a page boundary. The default when 0
60 * is given assumes that the entire data segment is to be stored, including
61 * the previous data and bss as well as any additional storage allocated with
62 * break (2).
63 *
64 * The new file is set up to start at entry_address.
65 *
66 * If you make improvements I'd like to get them too.
67 * harpo!utah-cs!thomas, thomas@Utah-20
68 *
69 */
70
71 /* Even more heavily modified by james@bigtex.cactus.org of Dell Computer Co.
72 * ELF support added.
73 *
74 * Basic theory: the data space of the running process needs to be
75 * dumped to the output file. Normally we would just enlarge the size
76 * of .data, scooting everything down. But we can't do that in ELF,
77 * because there is often something between the .data space and the
78 * .bss space.
79 *
80 * In the temacs dump below, notice that the Global Offset Table
81 * (.got) and the Dynamic link data (.dynamic) come between .data1 and
82 * .bss. It does not work to overlap .data with these fields.
83 *
84 * The solution is to create a new .data segment. This segment is
85 * filled with data from the current process. Since the contents of
86 * various sections refer to sections by index, the new .data segment
87 * is made the last in the table to avoid changing any existing index.
88
89 * This is an example of how the section headers are changed. "Addr"
90 * is a process virtual address. "Offset" is a file offset.
91
92 raid:/nfs/raid/src/dist-18.56/src> dump -h temacs
93
94 temacs:
95
96 **** SECTION HEADER TABLE ****
97 [No] Type Flags Addr Offset Size Name
98 Link Info Adralgn Entsize
99
100 [1] 1 2 0x80480d4 0xd4 0x13 .interp
101 0 0 0x1 0
102
103 [2] 5 2 0x80480e8 0xe8 0x388 .hash
104 3 0 0x4 0x4
105
106 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
107 4 1 0x4 0x10
108
109 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
110 0 0 0x1 0
111
112 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
113 3 7 0x4 0x8
114
115 [6] 1 6 0x8049348 0x1348 0x3 .init
116 0 0 0x4 0
117
118 [7] 1 6 0x804934c 0x134c 0x680 .plt
119 0 0 0x4 0x4
120
121 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
122 0 0 0x4 0
123
124 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
125 0 0 0x4 0
126
127 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
128 0 0 0x4 0
129
130 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
131 0 0 0x4 0
132
133 [12] 1 3 0x8088330 0x3f330 0x20afc .data
134 0 0 0x4 0
135
136 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
137 0 0 0x4 0
138
139 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
140 0 0 0x4 0x4
141
142 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
143 4 0 0x4 0x8
144
145 [16] 8 3 0x80a98f4 0x608f4 0x449c .bss
146 0 0 0x4 0
147
148 [17] 2 0 0 0x608f4 0x9b90 .symtab
149 18 371 0x4 0x10
150
151 [18] 3 0 0 0x6a484 0x8526 .strtab
152 0 0 0x1 0
153
154 [19] 3 0 0 0x729aa 0x93 .shstrtab
155 0 0 0x1 0
156
157 [20] 1 0 0 0x72a3d 0x68b7 .comment
158 0 0 0x1 0
159
160 raid:/nfs/raid/src/dist-18.56/src> dump -h xemacs
161
162 xemacs:
163
164 **** SECTION HEADER TABLE ****
165 [No] Type Flags Addr Offset Size Name
166 Link Info Adralgn Entsize
167
168 [1] 1 2 0x80480d4 0xd4 0x13 .interp
169 0 0 0x1 0
170
171 [2] 5 2 0x80480e8 0xe8 0x388 .hash
172 3 0 0x4 0x4
173
174 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
175 4 1 0x4 0x10
176
177 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
178 0 0 0x1 0
179
180 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
181 3 7 0x4 0x8
182
183 [6] 1 6 0x8049348 0x1348 0x3 .init
184 0 0 0x4 0
185
186 [7] 1 6 0x804934c 0x134c 0x680 .plt
187 0 0 0x4 0x4
188
189 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
190 0 0 0x4 0
191
192 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
193 0 0 0x4 0
194
195 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
196 0 0 0x4 0
197
198 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
199 0 0 0x4 0
200
201 [12] 1 3 0x8088330 0x3f330 0x20afc .data
202 0 0 0x4 0
203
204 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
205 0 0 0x4 0
206
207 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
208 0 0 0x4 0x4
209
210 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
211 4 0 0x4 0x8
212
213 [16] 8 3 0x80c6800 0x7d800 0 .bss
214 0 0 0x4 0
215
216 [17] 2 0 0 0x7d800 0x9b90 .symtab
217 18 371 0x4 0x10
218
219 [18] 3 0 0 0x87390 0x8526 .strtab
220 0 0 0x1 0
221
222 [19] 3 0 0 0x8f8b6 0x93 .shstrtab
223 0 0 0x1 0
224
225 [20] 1 0 0 0x8f949 0x68b7 .comment
226 0 0 0x1 0
227
228 [21] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
229 0 0 0x4 0
230
231 * This is an example of how the file header is changed. "Shoff" is
232 * the section header offset within the file. Since that table is
233 * after the new .data section, it is moved. "Shnum" is the number of
234 * sections, which we increment.
235 *
236 * "Phoff" is the file offset to the program header. "Phentsize" and
237 * "Shentsz" are the program and section header entries sizes respectively.
238 * These can be larger than the apparent struct sizes.
239
240 raid:/nfs/raid/src/dist-18.56/src> dump -f temacs
241
242 temacs:
243
244 **** ELF HEADER ****
245 Class Data Type Machine Version
246 Entry Phoff Shoff Flags Ehsize
247 Phentsize Phnum Shentsz Shnum Shstrndx
248
249 1 1 2 3 1
250 0x80499cc 0x34 0x792f4 0 0x34
251 0x20 5 0x28 21 19
252
253 raid:/nfs/raid/src/dist-18.56/src> dump -f xemacs
254
255 xemacs:
256
257 **** ELF HEADER ****
258 Class Data Type Machine Version
259 Entry Phoff Shoff Flags Ehsize
260 Phentsize Phnum Shentsz Shnum Shstrndx
261
262 1 1 2 3 1
263 0x80499cc 0x34 0x96200 0 0x34
264 0x20 5 0x28 22 19
265
266 * These are the program headers. "Offset" is the file offset to the
267 * segment. "Vaddr" is the memory load address. "Filesz" is the
268 * segment size as it appears in the file, and "Memsz" is the size in
269 * memory. Below, the third segment is the code and the fourth is the
270 * data: the difference between Filesz and Memsz is .bss
271
272 raid:/nfs/raid/src/dist-18.56/src> dump -o temacs
273
274 temacs:
275 ***** PROGRAM EXECUTION HEADER *****
276 Type Offset Vaddr Paddr
277 Filesz Memsz Flags Align
278
279 6 0x34 0x8048034 0
280 0xa0 0xa0 5 0
281
282 3 0xd4 0 0
283 0x13 0 4 0
284
285 1 0x34 0x8048034 0
286 0x3f2f9 0x3f2f9 5 0x1000
287
288 1 0x3f330 0x8088330 0
289 0x215c4 0x25a60 7 0x1000
290
291 2 0x60874 0x80a9874 0
292 0x80 0 7 0
293
294 raid:/nfs/raid/src/dist-18.56/src> dump -o xemacs
295
296 xemacs:
297 ***** PROGRAM EXECUTION HEADER *****
298 Type Offset Vaddr Paddr
299 Filesz Memsz Flags Align
300
301 6 0x34 0x8048034 0
302 0xa0 0xa0 5 0
303
304 3 0xd4 0 0
305 0x13 0 4 0
306
307 1 0x34 0x8048034 0
308 0x3f2f9 0x3f2f9 5 0x1000
309
310 1 0x3f330 0x8088330 0
311 0x3e4d0 0x3e4d0 7 0x1000
312
313 2 0x60874 0x80a9874 0
314 0x80 0 7 0
315
316
317 */
318 \f
319 /* Modified by wtien@urbana.mcd.mot.com of Motorola Inc.
320 *
321 * The above mechanism does not work if the unexeced ELF file is being
322 * re-layout by other applications (such as `strip'). All the applications
323 * that re-layout the internal of ELF will layout all sections in ascending
324 * order of their file offsets. After the re-layout, the data2 section will
325 * still be the LAST section in the section header vector, but its file offset
326 * is now being pushed far away down, and causes part of it not to be mapped
327 * in (ie. not covered by the load segment entry in PHDR vector), therefore
328 * causes the new binary to fail.
329 *
330 * The solution is to modify the unexec algorithm to insert the new data2
331 * section header right before the new bss section header, so their file
332 * offsets will be in the ascending order. Since some of the section's (all
333 * sections AFTER the bss section) indexes are now changed, we also need to
334 * modify some fields to make them point to the right sections. This is done
335 * by macro PATCH_INDEX. All the fields that need to be patched are:
336 *
337 * 1. ELF header e_shstrndx field.
338 * 2. section header sh_link and sh_info field.
339 * 3. symbol table entry st_shndx field.
340 *
341 * The above example now should look like:
342
343 **** SECTION HEADER TABLE ****
344 [No] Type Flags Addr Offset Size Name
345 Link Info Adralgn Entsize
346
347 [1] 1 2 0x80480d4 0xd4 0x13 .interp
348 0 0 0x1 0
349
350 [2] 5 2 0x80480e8 0xe8 0x388 .hash
351 3 0 0x4 0x4
352
353 [3] 11 2 0x8048470 0x470 0x7f0 .dynsym
354 4 1 0x4 0x10
355
356 [4] 3 2 0x8048c60 0xc60 0x3ad .dynstr
357 0 0 0x1 0
358
359 [5] 9 2 0x8049010 0x1010 0x338 .rel.plt
360 3 7 0x4 0x8
361
362 [6] 1 6 0x8049348 0x1348 0x3 .init
363 0 0 0x4 0
364
365 [7] 1 6 0x804934c 0x134c 0x680 .plt
366 0 0 0x4 0x4
367
368 [8] 1 6 0x80499cc 0x19cc 0x3c56f .text
369 0 0 0x4 0
370
371 [9] 1 6 0x8085f3c 0x3df3c 0x3 .fini
372 0 0 0x4 0
373
374 [10] 1 2 0x8085f40 0x3df40 0x69c .rodata
375 0 0 0x4 0
376
377 [11] 1 2 0x80865dc 0x3e5dc 0xd51 .rodata1
378 0 0 0x4 0
379
380 [12] 1 3 0x8088330 0x3f330 0x20afc .data
381 0 0 0x4 0
382
383 [13] 1 3 0x80a8e2c 0x5fe2c 0x89d .data1
384 0 0 0x4 0
385
386 [14] 1 3 0x80a96cc 0x606cc 0x1a8 .got
387 0 0 0x4 0x4
388
389 [15] 6 3 0x80a9874 0x60874 0x80 .dynamic
390 4 0 0x4 0x8
391
392 [16] 1 3 0x80a98f4 0x608f4 0x1cf0c .data
393 0 0 0x4 0
394
395 [17] 8 3 0x80c6800 0x7d800 0 .bss
396 0 0 0x4 0
397
398 [18] 2 0 0 0x7d800 0x9b90 .symtab
399 19 371 0x4 0x10
400
401 [19] 3 0 0 0x87390 0x8526 .strtab
402 0 0 0x1 0
403
404 [20] 3 0 0 0x8f8b6 0x93 .shstrtab
405 0 0 0x1 0
406
407 [21] 1 0 0 0x8f949 0x68b7 .comment
408 0 0 0x1 0
409
410 */
411 \f
412 #include <sys/types.h>
413 #include <stdio.h>
414 #include <sys/stat.h>
415 #include <memory.h>
416 #include <string.h>
417 #include <errno.h>
418 #include <unistd.h>
419 #include <fcntl.h>
420 #include <elf.h>
421 #include <sys/mman.h>
422
423 #ifndef emacs
424 #define fatal(a, b, c) fprintf (stderr, a, b, c), exit (1)
425 #else
426 extern void fatal (char *, ...);
427 #endif
428
429 #ifndef ELF_BSS_SECTION_NAME
430 #define ELF_BSS_SECTION_NAME ".bss"
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 ((int) (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 /* ****************************************************************
465 * unexec
466 *
467 * driving logic.
468 *
469 * In ELF, this works by replacing the old .bss section with a new
470 * .data section, and inserting an empty .bss immediately afterwards.
471 *
472 */
473 void
474 unexec (new_name, old_name, data_start, bss_start, entry_address)
475 char *new_name, *old_name;
476 unsigned data_start, bss_start, entry_address;
477 {
478 int new_file, old_file, new_file_size;
479
480 /* Pointers to the base of the image of the two files. */
481 caddr_t old_base, new_base;
482
483 /* Pointers to the file, program and section headers for the old and new
484 * files.
485 */
486 Elf32_Ehdr *old_file_h, *new_file_h;
487 Elf32_Phdr *old_program_h, *new_program_h;
488 Elf32_Shdr *old_section_h, *new_section_h;
489
490 /* Point to the section name table in the old file */
491 char *old_section_names;
492
493 Elf32_Addr old_bss_addr, new_bss_addr;
494 Elf32_Word old_bss_size, new_data2_size;
495 Elf32_Off new_data2_offset;
496 Elf32_Addr new_data2_addr;
497
498 int n, nn, old_bss_index, old_data_index, new_data2_index;
499 struct stat stat_buf;
500
501 /* Open the old file & map it into the address space. */
502
503 old_file = open (old_name, O_RDONLY);
504
505 if (old_file < 0)
506 fatal ("Can't open %s for reading: errno %d\n", old_name, errno);
507
508 if (fstat (old_file, &stat_buf) == -1)
509 fatal ("Can't fstat (%s): errno %d\n", old_name, errno);
510
511 old_base = mmap (0, stat_buf.st_size, PROT_READ, MAP_SHARED, old_file, 0);
512
513 if (old_base == (caddr_t) -1)
514 fatal ("Can't mmap (%s): errno %d\n", old_name, errno);
515
516 #ifdef DEBUG
517 fprintf (stderr, "mmap (%s, %x) -> %x\n", old_name, stat_buf.st_size,
518 old_base);
519 #endif
520
521 /* Get pointers to headers & section names */
522
523 old_file_h = (Elf32_Ehdr *) old_base;
524 old_program_h = (Elf32_Phdr *) ((byte *) old_base + old_file_h->e_phoff);
525 old_section_h = (Elf32_Shdr *) ((byte *) old_base + old_file_h->e_shoff);
526 old_section_names = (char *) old_base
527 + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset;
528
529 /* Find the old .bss section. Figure out parameters of the new
530 * data2 and bss sections.
531 */
532
533 for (old_bss_index = 1; old_bss_index < (int) old_file_h->e_shnum;
534 old_bss_index++)
535 {
536 #ifdef DEBUG
537 fprintf (stderr, "Looking for .bss - found %s\n",
538 old_section_names + OLD_SECTION_H (old_bss_index).sh_name);
539 #endif
540 if (!strcmp (old_section_names + OLD_SECTION_H (old_bss_index).sh_name,
541 ELF_BSS_SECTION_NAME))
542 break;
543 }
544 if (old_bss_index == old_file_h->e_shnum)
545 fatal ("Can't find .bss in %s.\n", old_name, 0);
546
547 old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr;
548 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size;
549 #if defined(emacs) || !defined(DEBUG)
550 new_bss_addr = (Elf32_Addr) sbrk (0);
551 #else
552 new_bss_addr = old_bss_addr + old_bss_size + 0x1234;
553 #endif
554 new_data2_addr = old_bss_addr;
555 new_data2_size = new_bss_addr - old_bss_addr;
556 new_data2_offset = OLD_SECTION_H (old_bss_index).sh_offset;
557
558 #ifdef DEBUG
559 fprintf (stderr, "old_bss_index %d\n", old_bss_index);
560 fprintf (stderr, "old_bss_addr %x\n", old_bss_addr);
561 fprintf (stderr, "old_bss_size %x\n", old_bss_size);
562 fprintf (stderr, "new_bss_addr %x\n", new_bss_addr);
563 fprintf (stderr, "new_data2_addr %x\n", new_data2_addr);
564 fprintf (stderr, "new_data2_size %x\n", new_data2_size);
565 fprintf (stderr, "new_data2_offset %x\n", new_data2_offset);
566 #endif
567
568 if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size)
569 fatal (".bss shrank when undumping???\n", 0, 0);
570
571 /* Set the output file to the right size and mmap it. Set
572 * pointers to various interesting objects. stat_buf still has
573 * old_file data.
574 */
575
576 new_file = open (new_name, O_RDWR | O_CREAT, 0666);
577 if (new_file < 0)
578 fatal ("Can't creat (%s): errno %d\n", new_name, errno);
579
580 new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_data2_size;
581
582 if (ftruncate (new_file, new_file_size))
583 fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
584
585 new_base = mmap (0, new_file_size, PROT_READ | PROT_WRITE, MAP_SHARED,
586 new_file, 0);
587
588 if (new_base == (caddr_t) -1)
589 fatal ("Can't mmap (%s): errno %d\n", new_name, errno);
590
591 new_file_h = (Elf32_Ehdr *) new_base;
592 new_program_h = (Elf32_Phdr *) ((byte *) new_base + old_file_h->e_phoff);
593 new_section_h = (Elf32_Shdr *)
594 ((byte *) new_base + old_file_h->e_shoff + new_data2_size);
595
596 /* Make our new file, program and section headers as copies of the
597 * originals.
598 */
599
600 memcpy (new_file_h, old_file_h, old_file_h->e_ehsize);
601 memcpy (new_program_h, old_program_h,
602 old_file_h->e_phnum * old_file_h->e_phentsize);
603
604 /* Modify the e_shstrndx if necessary. */
605 PATCH_INDEX (new_file_h->e_shstrndx);
606
607 /* Fix up file header. We'll add one section. Section header is
608 * further away now.
609 */
610
611 new_file_h->e_shoff += new_data2_size;
612 new_file_h->e_shnum += 1;
613
614 #ifdef DEBUG
615 fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff);
616 fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum);
617 fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff);
618 fprintf (stderr, "New section count %d\n", new_file_h->e_shnum);
619 #endif
620
621 /* Fix up a new program header. Extend the writable data segment so
622 * that the bss area is covered too. Find that segment by looking
623 * for a segment that ends just before the .bss area. Make sure
624 * that no segments are above the new .data2. Put a loop at the end
625 * to adjust the offset and address of any segment that is above
626 * data2, just in case we decide to allow this later.
627 */
628
629 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
630 {
631 /* Compute maximum of all requirements for alignment of section. */
632 int alignment = (NEW_PROGRAM_H (n)).p_align;
633 if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment)
634 alignment = OLD_SECTION_H (old_bss_index).sh_addralign;
635
636 if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz > old_bss_addr)
637 fatal ("Program segment above .bss in %s\n", old_name, 0);
638
639 if (NEW_PROGRAM_H (n).p_type == PT_LOAD
640 && (round_up ((NEW_PROGRAM_H (n)).p_vaddr
641 + (NEW_PROGRAM_H (n)).p_filesz,
642 alignment)
643 == round_up (old_bss_addr, alignment)))
644 break;
645 }
646 if (n < 0)
647 fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0);
648
649 NEW_PROGRAM_H (n).p_filesz += new_data2_size;
650 NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz;
651
652 #if 0 /* Maybe allow section after data2 - does this ever happen? */
653 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
654 {
655 if (NEW_PROGRAM_H (n).p_vaddr
656 && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr)
657 NEW_PROGRAM_H (n).p_vaddr += new_data2_size - old_bss_size;
658
659 if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset)
660 NEW_PROGRAM_H (n).p_offset += new_data2_size;
661 }
662 #endif
663
664 /* Fix up section headers based on new .data2 section. Any section
665 * whose offset or virtual address is after the new .data2 section
666 * gets its value adjusted. .bss size becomes zero and new address
667 * is set. data2 section header gets added by copying the existing
668 * .data header and modifying the offset, address and size.
669 */
670 for (old_data_index = 1; old_data_index < (int) old_file_h->e_shnum;
671 old_data_index++)
672 if (!strcmp (old_section_names + OLD_SECTION_H (old_data_index).sh_name,
673 ".data"))
674 break;
675 if (old_data_index == old_file_h->e_shnum)
676 fatal ("Can't find .data in %s.\n", old_name, 0);
677
678 /* Walk through all section headers, insert the new data2 section right
679 before the new bss section. */
680 for (n = 1, nn = 1; n < (int) old_file_h->e_shnum; n++, nn++)
681 {
682 caddr_t src;
683 /* If it is bss section, insert the new data2 section before it. */
684 if (n == old_bss_index)
685 {
686 /* Steal the data section header for this data2 section. */
687 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index),
688 new_file_h->e_shentsize);
689
690 NEW_SECTION_H (nn).sh_addr = new_data2_addr;
691 NEW_SECTION_H (nn).sh_offset = new_data2_offset;
692 NEW_SECTION_H (nn).sh_size = new_data2_size;
693 /* Use the bss section's alignment. This will assure that the
694 new data2 section always be placed in the same spot as the old
695 bss section by any other application. */
696 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign;
697
698 /* Now copy over what we have in the memory now. */
699 memcpy (NEW_SECTION_H (nn).sh_offset + new_base,
700 (caddr_t) OLD_SECTION_H (n).sh_addr,
701 new_data2_size);
702 nn++;
703 }
704
705 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
706 old_file_h->e_shentsize);
707
708 /* The new bss section's size is zero, and its file offset and virtual
709 address should be off by NEW_DATA2_SIZE. */
710 if (n == old_bss_index)
711 {
712 /* NN should be `old_bss_index + 1' at this point. */
713 NEW_SECTION_H (nn).sh_offset += new_data2_size;
714 NEW_SECTION_H (nn).sh_addr += new_data2_size;
715 /* Let the new bss section address alignment be the same as the
716 section address alignment followed the old bss section, so
717 this section will be placed in exactly the same place. */
718 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign;
719 NEW_SECTION_H (nn).sh_size = 0;
720 }
721 /* Any section that was original placed AFTER the bss section should now
722 be off by NEW_DATA2_SIZE. */
723 else if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset)
724 NEW_SECTION_H (nn).sh_offset += new_data2_size;
725
726 /* If any section hdr refers to the section after the new .data
727 section, make it refer to next one because we have inserted
728 a new section in between. */
729
730 PATCH_INDEX (NEW_SECTION_H (nn).sh_link);
731 PATCH_INDEX (NEW_SECTION_H (nn).sh_info);
732
733 /* Now, start to copy the content of sections. */
734 if (NEW_SECTION_H (nn).sh_type == SHT_NULL
735 || NEW_SECTION_H (nn).sh_type == SHT_NOBITS)
736 continue;
737
738 /* Write out the sections. .data and .data1 (and data2, called
739 * ".data" in the strings table) get copied from the current process
740 * instead of the old file.
741 */
742 if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data")
743 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
744 ".data1"))
745 src = (caddr_t) OLD_SECTION_H (n).sh_addr;
746 else
747 src = old_base + OLD_SECTION_H (n).sh_offset;
748
749 memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src,
750 NEW_SECTION_H (nn).sh_size);
751
752 /* If it is the symbol table, its st_shndx field needs to be patched. */
753 if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB
754 || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM)
755 {
756 Elf32_Shdr *spt = &NEW_SECTION_H (nn);
757 unsigned int num = spt->sh_size / spt->sh_entsize;
758 Elf32_Sym * sym = (Elf32_Sym *) (NEW_SECTION_H (nn).sh_offset +
759 new_base);
760 for (; num--; sym++)
761 {
762 if ((sym->st_shndx == SHN_UNDEF)
763 || (sym->st_shndx == SHN_ABS)
764 || (sym->st_shndx == SHN_COMMON))
765 continue;
766
767 PATCH_INDEX (sym->st_shndx);
768 }
769 }
770 }
771
772 /* Update the symbol values of _edata and _end. */
773 for (n = new_file_h->e_shnum - 1; n; n--)
774 {
775 byte *symnames;
776 Elf32_Sym *symp, *symendp;
777
778 if (NEW_SECTION_H (n).sh_type != SHT_DYNSYM
779 && NEW_SECTION_H (n).sh_type != SHT_SYMTAB)
780 continue;
781
782 symnames = NEW_SECTION_H (NEW_SECTION_H (n).sh_link).sh_offset + new_base;
783 symp = (Elf32_Sym *) (NEW_SECTION_H (n).sh_offset + new_base);
784 symendp = (Elf32_Sym *) ((byte *)symp + NEW_SECTION_H (n).sh_size);
785
786 for (; symp < symendp; symp ++)
787 if (strcmp ((char *) (symnames + symp->st_name), "_end") == 0
788 || strcmp ((char *) (symnames + symp->st_name), "_edata") == 0)
789 memcpy (&symp->st_value, &new_bss_addr, sizeof (new_bss_addr));
790 }
791
792 /* Close the files and make the new file executable */
793
794 if (close (old_file))
795 fatal ("Can't close (%s): errno %d\n", old_name, errno);
796
797 if (close (new_file))
798 fatal ("Can't close (%s): errno %d\n", new_name, errno);
799
800 if (stat (new_name, &stat_buf) == -1)
801 fatal ("Can't stat (%s): errno %d\n", new_name, errno);
802
803 n = umask (777);
804 umask (n);
805 stat_buf.st_mode |= 0111 & ~n;
806 if (chmod (new_name, stat_buf.st_mode) == -1)
807 fatal ("Can't chmod (%s): errno %d\n", new_name, errno);
808 }