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[bpt/emacs.git] / src / unexelf.c
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e40c4104
RS		 1/* Copyright (C) 1985, 1986, 1987, 1988, 1990, 1992
2 Free Software Foundation, Inc.
d427b66a 3
e40c4104
RS		 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.
d427b66a
JB		 17
18In other words, you are welcome to use, share and improve this program.
19You are forbidden to forbid anyone else to use, share and improve
20what 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
92raid:/nfs/raid/src/dist-18.56/src> dump -h temacs
93
94temacs:
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
160raid:/nfs/raid/src/dist-18.56/src> dump -h xemacs
161
162xemacs:
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
240raid:/nfs/raid/src/dist-18.56/src> dump -f temacs
241
242temacs:
243
244 **** ELF HEADER ****
245Class Data Type Machine Version
246Entry Phoff Shoff Flags Ehsize
247Phentsize Phnum Shentsz Shnum Shstrndx
248
2491 1 2 3 1
2500x80499cc 0x34 0x792f4 0 0x34
2510x20 5 0x28 21 19
252
253raid:/nfs/raid/src/dist-18.56/src> dump -f xemacs
254
255xemacs:
256
257 **** ELF HEADER ****
258Class Data Type Machine Version
259Entry Phoff Shoff Flags Ehsize
260Phentsize Phnum Shentsz Shnum Shstrndx
261
2621 1 2 3 1
2630x80499cc 0x34 0x96200 0 0x34
2640x20 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
272raid:/nfs/raid/src/dist-18.56/src> dump -o temacs
273
274temacs:
275 ***** PROGRAM EXECUTION HEADER *****
276Type Offset Vaddr Paddr
277Filesz Memsz Flags Align
278
2796 0x34 0x8048034 0
2800xa0 0xa0 5 0
281
2823 0xd4 0 0
2830x13 0 4 0
284
2851 0x34 0x8048034 0
2860x3f2f9 0x3f2f9 5 0x1000
287
2881 0x3f330 0x8088330 0
2890x215c4 0x25a60 7 0x1000
290
2912 0x60874 0x80a9874 0
2920x80 0 7 0
293
294raid:/nfs/raid/src/dist-18.56/src> dump -o xemacs
295
296xemacs:
297 ***** PROGRAM EXECUTION HEADER *****
298Type Offset Vaddr Paddr
299Filesz Memsz Flags Align
300
3016 0x34 0x8048034 0
3020xa0 0xa0 5 0
303
3043 0xd4 0 0
3050x13 0 4 0
306
3071 0x34 0x8048034 0
3080x3f2f9 0x3f2f9 5 0x1000
309
3101 0x3f330 0x8088330 0
3110x3e4d0 0x3e4d0 7 0x1000
312
3132 0x60874 0x80a9874 0
3140x80 0 7 0
315
316
317 */
e40c4104
RS		 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
d427b66a 349
e40c4104
RS		 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
d427b66a
JB		 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
d7cb42c3 424#define fatal(a, b, c) fprintf (stderr, a, b, c), exit (1)
d427b66a 425#else
d7cb42c3 426extern void fatal (char *, ...);
d427b66a
JB		 427#endif
428
d8858cfe
RS		 429#ifndef ELF_BSS_SECTION_NAME
430#define ELF_BSS_SECTION_NAME ".bss"
431#endif
432
d427b66a
JB		 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
e40c4104
RS		 446#define PATCH_INDEX(n) \
447 do { \
d7cb42c3 448 if ((int) (n) >= old_bss_index) \
e40c4104 449 (n)++; } while (0)
d427b66a
JB		 450typedef unsigned char byte;
451
e40c4104
RS		 452/* Round X up to a multiple of Y. */
453
454int
455round_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
d427b66a
JB		 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 */
473void
474unexec (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 extern unsigned int bss_end;
479 int new_file, old_file, new_file_size;
480
481 /* Pointers to the base of the image of the two files. */
482 caddr_t old_base, new_base;
483
484 /* Pointers to the file, program and section headers for the old and new
485 * files.
486 */
487 Elf32_Ehdr *old_file_h, *new_file_h;
488 Elf32_Phdr *old_program_h, *new_program_h;
489 Elf32_Shdr *old_section_h, *new_section_h;
490
491 /* Point to the section name table in the old file */
492 char *old_section_names;
493
494 Elf32_Addr old_bss_addr, new_bss_addr;
495 Elf32_Word old_bss_size, new_data2_size;
496 Elf32_Off new_data2_offset;
497 Elf32_Addr new_data2_addr;
498
e40c4104 499 int n, nn, old_bss_index, old_data_index, new_data2_index;
d427b66a
JB		 500 struct stat stat_buf;
501
502 /* Open the old file & map it into the address space. */
503
504 old_file = open (old_name, O_RDONLY);
505
506 if (old_file < 0)
507 fatal ("Can't open %s for reading: errno %d\n", old_name, errno);
508
509 if (fstat (old_file, &stat_buf) == -1)
d7cb42c3 510 fatal ("Can't fstat (%s): errno %d\n", old_name, errno);
d427b66a
JB		 511
512 old_base = mmap (0, stat_buf.st_size, PROT_READ, MAP_SHARED, old_file, 0);
513
514 if (old_base == (caddr_t) -1)
d7cb42c3 515 fatal ("Can't mmap (%s): errno %d\n", old_name, errno);
d427b66a
JB		 516
517#ifdef DEBUG
d7cb42c3 518 fprintf (stderr, "mmap (%s, %x) -> %x\n", old_name, stat_buf.st_size,
d427b66a
JB		 519 old_base);
520#endif
521
522 /* Get pointers to headers & section names */
523
524 old_file_h = (Elf32_Ehdr *) old_base;
525 old_program_h = (Elf32_Phdr *) ((byte *) old_base + old_file_h->e_phoff);
526 old_section_h = (Elf32_Shdr *) ((byte *) old_base + old_file_h->e_shoff);
527 old_section_names = (char *) old_base
d7cb42c3 528 + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset;
d427b66a
JB		 529
530 /* Find the old .bss section. Figure out parameters of the new
531 * data2 and bss sections.
532 */
533
d7cb42c3
RS		 534 for (old_bss_index = 1; old_bss_index < (int) old_file_h->e_shnum;
535 old_bss_index++)
d427b66a
JB		 536 {
537#ifdef DEBUG
538 fprintf (stderr, "Looking for .bss - found %s\n",
d7cb42c3 539 old_section_names + OLD_SECTION_H (old_bss_index).sh_name);
d427b66a 540#endif
d7cb42c3 541 if (!strcmp (old_section_names + OLD_SECTION_H (old_bss_index).sh_name,
d8858cfe 542 ELF_BSS_SECTION_NAME))
d427b66a
JB		 543 break;
544 }
545 if (old_bss_index == old_file_h->e_shnum)
546 fatal ("Can't find .bss in %s.\n", old_name, 0);
547
d7cb42c3
RS		 548 old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr;
549 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size;
d427b66a
JB		 550#if defined(emacs) || !defined(DEBUG)
551 bss_end = (unsigned int) sbrk (0);
552 new_bss_addr = (Elf32_Addr) bss_end;
553#else
554 new_bss_addr = old_bss_addr + old_bss_size + 0x1234;
555#endif
556 new_data2_addr = old_bss_addr;
557 new_data2_size = new_bss_addr - old_bss_addr;
d7cb42c3 558 new_data2_offset = OLD_SECTION_H (old_bss_index).sh_offset;
d427b66a
JB		 559
560#ifdef DEBUG
561 fprintf (stderr, "old_bss_index %d\n", old_bss_index);
562 fprintf (stderr, "old_bss_addr %x\n", old_bss_addr);
563 fprintf (stderr, "old_bss_size %x\n", old_bss_size);
564 fprintf (stderr, "new_bss_addr %x\n", new_bss_addr);
565 fprintf (stderr, "new_data2_addr %x\n", new_data2_addr);
566 fprintf (stderr, "new_data2_size %x\n", new_data2_size);
567 fprintf (stderr, "new_data2_offset %x\n", new_data2_offset);
568#endif
569
570 if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size)
571 fatal (".bss shrank when undumping???\n", 0, 0);
572
d7cb42c3 573 /* Set the output file to the right size and mmap it. Set
d427b66a
JB		 574 * pointers to various interesting objects. stat_buf still has
575 * old_file data.
576 */
577
578 new_file = open (new_name, O_RDWR | O_CREAT, 0666);
579 if (new_file < 0)
d7cb42c3 580 fatal ("Can't creat (%s): errno %d\n", new_name, errno);
d427b66a
JB		 581
582 new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_data2_size;
583
584 if (ftruncate (new_file, new_file_size))
d7cb42c3 585 fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
d427b66a
JB		 586
587 new_base = mmap (0, new_file_size, PROT_READ | PROT_WRITE, MAP_SHARED,
588 new_file, 0);
589
590 if (new_base == (caddr_t) -1)
d7cb42c3 591 fatal ("Can't mmap (%s): errno %d\n", new_name, errno);
d427b66a
JB		 592
593 new_file_h = (Elf32_Ehdr *) new_base;
594 new_program_h = (Elf32_Phdr *) ((byte *) new_base + old_file_h->e_phoff);
595 new_section_h = (Elf32_Shdr *)
596 ((byte *) new_base + old_file_h->e_shoff + new_data2_size);
597
598 /* Make our new file, program and section headers as copies of the
599 * originals.
600 */
601
602 memcpy (new_file_h, old_file_h, old_file_h->e_ehsize);
603 memcpy (new_program_h, old_program_h,
604 old_file_h->e_phnum * old_file_h->e_phentsize);
e40c4104
RS		 605
606 /* Modify the e_shstrndx if necessary. */
607 PATCH_INDEX (new_file_h->e_shstrndx);
d427b66a
JB		 608
609 /* Fix up file header. We'll add one section. Section header is
610 * further away now.
611 */
612
613 new_file_h->e_shoff += new_data2_size;
614 new_file_h->e_shnum += 1;
615
616#ifdef DEBUG
617 fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff);
618 fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum);
619 fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff);
620 fprintf (stderr, "New section count %d\n", new_file_h->e_shnum);
621#endif
622
623 /* Fix up a new program header. Extend the writable data segment so
624 * that the bss area is covered too. Find that segment by looking
625 * for a segment that ends just before the .bss area. Make sure
626 * that no segments are above the new .data2. Put a loop at the end
627 * to adjust the offset and address of any segment that is above
628 * data2, just in case we decide to allow this later.
629 */
630
631 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
632 {
e40c4104
RS		 633 /* Compute maximum of all requirements for alignment of section. */
634 int alignment = (NEW_PROGRAM_H (n)).p_align;
635 if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment)
636 alignment = OLD_SECTION_H (old_bss_index).sh_addralign;
637
d7cb42c3 638 if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz > old_bss_addr)
d427b66a
JB		 639 fatal ("Program segment above .bss in %s\n", old_name, 0);
640
d7cb42c3 641 if (NEW_PROGRAM_H (n).p_type == PT_LOAD
e40c4104
RS		 642 && (round_up ((NEW_PROGRAM_H (n)).p_vaddr
643 + (NEW_PROGRAM_H (n)).p_filesz,
644 alignment)
645 == round_up (old_bss_addr, alignment)))
d427b66a
JB		 646 break;
647 }
648 if (n < 0)
649 fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0);
650
d7cb42c3
RS		 651 NEW_PROGRAM_H (n).p_filesz += new_data2_size;
652 NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz;
d427b66a
JB		 653
654#if 0 /* Maybe allow section after data2 - does this ever happen? */
655 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
656 {
d7cb42c3
RS		 657 if (NEW_PROGRAM_H (n).p_vaddr
658 && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr)
659 NEW_PROGRAM_H (n).p_vaddr += new_data2_size - old_bss_size;
d427b66a 660
d7cb42c3
RS		 661 if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset)
662 NEW_PROGRAM_H (n).p_offset += new_data2_size;
d427b66a
JB		 663 }
664#endif
665
666 /* Fix up section headers based on new .data2 section. Any section
667 * whose offset or virtual address is after the new .data2 section
668 * gets its value adjusted. .bss size becomes zero and new address
669 * is set. data2 section header gets added by copying the existing
670 * .data header and modifying the offset, address and size.
671 */
d7cb42c3 672 for (old_data_index = 1; old_data_index < (int) old_file_h->e_shnum;
d427b66a 673 old_data_index++)
d7cb42c3 674 if (!strcmp (old_section_names + OLD_SECTION_H (old_data_index).sh_name,
d427b66a
JB		 675 ".data"))
676 break;
677 if (old_data_index == old_file_h->e_shnum)
678 fatal ("Can't find .data in %s.\n", old_name, 0);
679
e40c4104
RS		 680 /* Walk through all section headers, insert the new data2 section right
681 before the new bss section. */
d7cb42c3 682 for (n = 1, nn = 1; n < (int) old_file_h->e_shnum; n++, nn++)
d427b66a
JB		 683 {
684 caddr_t src;
e40c4104
RS		 685 /* If it is bss section, insert the new data2 section before it. */
686 if (n == old_bss_index)
687 {
688 /* Steal the data section header for this data2 section. */
d7cb42c3 689 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index),
e40c4104
RS		 690 new_file_h->e_shentsize);
691
d7cb42c3
RS		 692 NEW_SECTION_H (nn).sh_addr = new_data2_addr;
693 NEW_SECTION_H (nn).sh_offset = new_data2_offset;
694 NEW_SECTION_H (nn).sh_size = new_data2_size;
e40c4104
RS		 695 /* Use the bss section's alignment. This will assure that the
696 new data2 section always be placed in the same spot as the old
697 bss section by any other application. */
d7cb42c3 698 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign;
e40c4104
RS		 699
700 /* Now copy over what we have in the memory now. */
d7cb42c3
RS		 701 memcpy (NEW_SECTION_H (nn).sh_offset + new_base,
702 (caddr_t) OLD_SECTION_H (n).sh_addr,
e40c4104
RS		 703 new_data2_size);
704 nn++;
705 }
706
d7cb42c3 707 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
e40c4104
RS		 708 old_file_h->e_shentsize);
709
710 /* The new bss section's size is zero, and its file offset and virtual
711 address should be off by NEW_DATA2_SIZE. */
712 if (n == old_bss_index)
713 {
714 /* NN should be `old_bss_index + 1' at this point. */
d7cb42c3
RS		 715 NEW_SECTION_H (nn).sh_offset += new_data2_size;
716 NEW_SECTION_H (nn).sh_addr += new_data2_size;
e40c4104
RS		 717 /* Let the new bss section address alignment be the same as the
718 section address alignment followed the old bss section, so
719 this section will be placed in exactly the same place. */
d7cb42c3
RS		 720 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign;
721 NEW_SECTION_H (nn).sh_size = 0;
e40c4104
RS		 722 }
723 /* Any section that was original placed AFTER the bss section should now
724 be off by NEW_DATA2_SIZE. */
d7cb42c3
RS		 725 else if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset)
726 NEW_SECTION_H (nn).sh_offset += new_data2_size;
e40c4104
RS		 727
728 /* If any section hdr refers to the section after the new .data
729 section, make it refer to next one because we have inserted
730 a new section in between. */
731
d7cb42c3
RS		 732 PATCH_INDEX (NEW_SECTION_H (nn).sh_link);
733 PATCH_INDEX (NEW_SECTION_H (nn).sh_info);
e40c4104
RS		 734
735 /* Now, start to copy the content of sections. */
d7cb42c3
RS		 736 if (NEW_SECTION_H (nn).sh_type == SHT_NULL
737 || NEW_SECTION_H (nn).sh_type == SHT_NOBITS)
d427b66a 738 continue;
e40c4104
RS		 739
740 /* Write out the sections. .data and .data1 (and data2, called
741 * ".data" in the strings table) get copied from the current process
742 * instead of the old file.
743 */
d7cb42c3
RS		 744 if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data")
745 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
d427b66a 746 ".data1"))
d7cb42c3 747 src = (caddr_t) OLD_SECTION_H (n).sh_addr;
d427b66a 748 else
d7cb42c3 749 src = old_base + OLD_SECTION_H (n).sh_offset;
e40c4104 750
d7cb42c3
RS		 751 memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src,
752 NEW_SECTION_H (nn).sh_size);
e40c4104
RS		 753
754 /* If it is the symbol table, its st_shndx field needs to be patched. */
d7cb42c3
RS		 755 if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB
756 || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM)
e40c4104 757 {
d7cb42c3 758 Elf32_Shdr *spt = &NEW_SECTION_H (nn);
e40c4104 759 unsigned int num = spt->sh_size / spt->sh_entsize;
d7cb42c3 760 Elf32_Sym * sym = (Elf32_Sym *) (NEW_SECTION_H (nn).sh_offset +
e40c4104
RS		 761 new_base);
762 for (; num--; sym++)
763 {
764 if ((sym->st_shndx == SHN_UNDEF)
765 || (sym->st_shndx == SHN_ABS)
766 || (sym->st_shndx == SHN_COMMON))
767 continue;
768
d7cb42c3 769 PATCH_INDEX (sym->st_shndx);
e40c4104
RS		 770 }
771 }
d427b66a
JB		 772 }
773
774 /* Close the files and make the new file executable */
775
776 if (close (old_file))
d7cb42c3 777 fatal ("Can't close (%s): errno %d\n", old_name, errno);
d427b66a
JB		 778
779 if (close (new_file))
d7cb42c3 780 fatal ("Can't close (%s): errno %d\n", new_name, errno);
d427b66a
JB		 781
782 if (stat (new_name, &stat_buf) == -1)
d7cb42c3 783 fatal ("Can't stat (%s): errno %d\n", new_name, errno);
d427b66a
JB		 784
785 n = umask (777);
786 umask (n);
787 stat_buf.st_mode |= 0111 & ~n;
788 if (chmod (new_name, stat_buf.st_mode) == -1)
d7cb42c3 789 fatal ("Can't chmod (%s): errno %d\n", new_name, errno);
d427b66a 790}
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