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[bpt/emacs.git] / src / unexelf1.c
1 /* Copyright (C) 1985, 1986, 1987, 1988, 1990, 1992
2 Free Software Foundation, Inc.
3
4 This file is part of GNU Emacs.
5
6 GNU Emacs is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
10
11 GNU Emacs is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GNU Emacs; see the file COPYING. If not, write to
18 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA.
20
21 In other words, you are welcome to use, share and improve this program.
22 You are forbidden to forbid anyone else to use, share and improve
23 what you give them. Help stamp out software-hoarding! */
24
25
26 /*
27 * unexec.c - Convert a running program into an a.out file.
28 *
29 * Author: Spencer W. Thomas
30 * Computer Science Dept.
31 * University of Utah
32 * Date: Tue Mar 2 1982
33 * Modified heavily since then.
34 *
35 * Synopsis:
36 * unexec (new_name, 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 <sys/mman.h>
425
426 #ifdef __alpha__
427 # include <sym.h> /* get COFF debugging symbol table declaration */
428 #endif
429
430 #if __GNU_LIBRARY__ - 0 >= 6
431 # include <link.h> /* get ElfW etc */
432 #endif
433
434 #ifndef ElfW
435 # ifdef __STDC__
436 # define ElfW(type) Elf32_##type
437 # else
438 # define ElfW(type) Elf32_/**/type
439 # endif
440 #endif
441
442 #ifndef emacs
443 #define fatal(a, b, c) fprintf (stderr, a, b, c), exit (1)
444 #else
445 #include <config.h>
446 extern void fatal (char *, ...);
447 #endif
448
449 #ifndef ELF_BSS_SECTION_NAME
450 #define ELF_BSS_SECTION_NAME ".bss"
451 #endif
452
453 /* Get the address of a particular section or program header entry,
454 * accounting for the size of the entries.
455 */
456 /*
457 On PPC Reference Platform running Solaris 2.5.1
458 the plt section is also of type NOBI like the bss section.
459 (not really stored) and therefore sections after the bss
460 section start at the plt offset. The plt section is always
461 the one just before the bss section.
462 Thus, we modify the test from
463 if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset)
464 to
465 if (NEW_SECTION_H (nn).sh_offset >=
466 OLD_SECTION_H (old_bss_index-1).sh_offset)
467 This is just a hack. We should put the new data section
468 before the .plt section.
469 And we should not have this routine at all but use
470 the libelf library to read the old file and create the new
471 file.
472 The changed code is minimal and depends on prep set in m/prep.h
473 Erik Deumens
474 Quantum Theory Project
475 University of Florida
476 deumens@qtp.ufl.edu
477 Apr 23, 1996
478 */
479
480 #define OLD_SECTION_H(n) \
481 (*(ElfW(Shdr) *) ((byte *) old_section_h + old_file_h->e_shentsize * (n)))
482 #define NEW_SECTION_H(n) \
483 (*(ElfW(Shdr) *) ((byte *) new_section_h + new_file_h->e_shentsize * (n)))
484 #define OLD_PROGRAM_H(n) \
485 (*(ElfW(Phdr) *) ((byte *) old_program_h + old_file_h->e_phentsize * (n)))
486 #define NEW_PROGRAM_H(n) \
487 (*(ElfW(Phdr) *) ((byte *) new_program_h + new_file_h->e_phentsize * (n)))
488
489 #define PATCH_INDEX(n) \
490 do { \
491 if ((int) (n) >= old_bss_index) \
492 (n)++; } while (0)
493 typedef unsigned char byte;
494
495 /* Round X up to a multiple of Y. */
496
497 int
498 round_up (x, y)
499 int x, y;
500 {
501 int rem = x % y;
502 if (rem == 0)
503 return x;
504 return x - rem + y;
505 }
506
507 /* ****************************************************************
508 * unexec
509 *
510 * driving logic.
511 *
512 * In ELF, this works by replacing the old .bss section with a new
513 * .data section, and inserting an empty .bss immediately afterwards.
514 *
515 */
516 void
517 unexec (new_name, old_name, data_start, bss_start, entry_address)
518 char *new_name, *old_name;
519 unsigned data_start, bss_start, entry_address;
520 {
521 int new_file, old_file, new_file_size;
522
523 /* Pointers to the base of the image of the two files. */
524 caddr_t old_base, new_base;
525
526 /* Pointers to the file, program and section headers for the old and new
527 * files.
528 */
529 ElfW(Ehdr) *old_file_h, *new_file_h;
530 ElfW(Phdr) *old_program_h, *new_program_h;
531 ElfW(Shdr) *old_section_h, *new_section_h;
532
533 /* Point to the section name table in the old file */
534 char *old_section_names;
535
536 ElfW(Addr) old_bss_addr, new_bss_addr;
537 ElfW(Word) old_bss_size, new_data2_size;
538 ElfW(Off) new_data2_offset;
539 ElfW(Addr) new_data2_addr;
540
541 int n, nn, old_bss_index, old_data_index, new_data2_index;
542 struct stat stat_buf;
543
544 /* Open the old file & map it into the address space. */
545
546 old_file = open (old_name, O_RDONLY);
547
548 if (old_file < 0)
549 fatal ("Can't open %s for reading: errno %d\n", old_name, errno);
550
551 if (fstat (old_file, &stat_buf) == -1)
552 fatal ("Can't fstat (%s): errno %d\n", old_name, errno);
553
554 old_base = mmap (0, stat_buf.st_size, PROT_READ, MAP_SHARED, old_file, 0);
555
556 if (old_base == (caddr_t) -1)
557 fatal ("Can't mmap (%s): errno %d\n", old_name, errno);
558
559 #ifdef DEBUG
560 fprintf (stderr, "mmap (%s, %x) -> %x\n", old_name, stat_buf.st_size,
561 old_base);
562 #endif
563
564 /* Get pointers to headers & section names */
565
566 old_file_h = (ElfW(Ehdr) *) old_base;
567 old_program_h = (ElfW(Phdr) *) ((byte *) old_base + old_file_h->e_phoff);
568 old_section_h = (ElfW(Shdr) *) ((byte *) old_base + old_file_h->e_shoff);
569 old_section_names = (char *) old_base
570 + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset;
571
572 /* Find the old .bss section. Figure out parameters of the new
573 * data2 and bss sections.
574 */
575
576 for (old_bss_index = 1; old_bss_index < (int) old_file_h->e_shnum;
577 old_bss_index++)
578 {
579 #ifdef DEBUG
580 fprintf (stderr, "Looking for .bss - found %s\n",
581 old_section_names + OLD_SECTION_H (old_bss_index).sh_name);
582 #endif
583 if (!strcmp (old_section_names + OLD_SECTION_H (old_bss_index).sh_name,
584 ELF_BSS_SECTION_NAME))
585 break;
586 }
587 if (old_bss_index == old_file_h->e_shnum)
588 fatal ("Can't find .bss in %s.\n", old_name, 0);
589
590 old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr;
591 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size;
592 #if defined(emacs) || !defined(DEBUG)
593 new_bss_addr = (ElfW(Addr)) sbrk (0);
594 #else
595 new_bss_addr = old_bss_addr + old_bss_size + 0x1234;
596 #endif
597 new_data2_addr = old_bss_addr;
598 new_data2_size = new_bss_addr - old_bss_addr;
599 new_data2_offset = OLD_SECTION_H (old_bss_index).sh_offset;
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 #endif
610
611 if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size)
612 fatal (".bss shrank when undumping???\n", 0, 0);
613
614 /* Set the output file to the right size and mmap it. Set
615 * pointers to various interesting objects. stat_buf still has
616 * old_file data.
617 */
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_data2_size;
624
625 if (ftruncate (new_file, new_file_size))
626 fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
627
628 #ifdef UNEXEC_USE_MAP_PRIVATE
629 new_base = mmap (0, new_file_size, PROT_READ | PROT_WRITE, MAP_PRIVATE,
630 new_file, 0);
631 #else
632 new_base = mmap (0, new_file_size, PROT_READ | PROT_WRITE, MAP_SHARED,
633 new_file, 0);
634 #endif
635
636 if (new_base == (caddr_t) -1)
637 fatal ("Can't mmap (%s): errno %d\n", new_name, errno);
638
639 new_file_h = (ElfW(Ehdr) *) new_base;
640 new_program_h = (ElfW(Phdr) *) ((byte *) new_base + old_file_h->e_phoff);
641 new_section_h = (ElfW(Shdr) *)
642 ((byte *) new_base + old_file_h->e_shoff + new_data2_size);
643
644 /* Make our new file, program and section headers as copies of the
645 * originals.
646 */
647
648 memcpy (new_file_h, old_file_h, old_file_h->e_ehsize);
649 memcpy (new_program_h, old_program_h,
650 old_file_h->e_phnum * old_file_h->e_phentsize);
651
652 /* Modify the e_shstrndx if necessary. */
653 PATCH_INDEX (new_file_h->e_shstrndx);
654
655 /* Fix up file header. We'll add one section. Section header is
656 * further away now.
657 */
658
659 new_file_h->e_shoff += new_data2_size;
660 new_file_h->e_shnum += 1;
661
662 #ifdef DEBUG
663 fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff);
664 fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum);
665 fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff);
666 fprintf (stderr, "New section count %d\n", new_file_h->e_shnum);
667 #endif
668
669 /* Fix up a new program header. Extend the writable data segment so
670 * that the bss area is covered too. Find that segment by looking
671 * for a segment that ends just before the .bss area. Make sure
672 * that no segments are above the new .data2. Put a loop at the end
673 * to adjust the offset and address of any segment that is above
674 * data2, just in case we decide to allow this later.
675 */
676
677 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
678 {
679 /* Compute maximum of all requirements for alignment of section. */
680 int alignment = (NEW_PROGRAM_H (n)).p_align;
681 if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment)
682 alignment = OLD_SECTION_H (old_bss_index).sh_addralign;
683
684 if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz > old_bss_addr)
685 fatal ("Program segment above .bss in %s\n", old_name, 0);
686
687 if (NEW_PROGRAM_H (n).p_type == PT_LOAD
688 && (round_up ((NEW_PROGRAM_H (n)).p_vaddr
689 + (NEW_PROGRAM_H (n)).p_filesz,
690 alignment)
691 == round_up (old_bss_addr, alignment)))
692 break;
693 }
694 if (n < 0)
695 fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0);
696
697 NEW_PROGRAM_H (n).p_filesz += new_data2_size;
698 NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz;
699
700 #if 0 /* Maybe allow section after data2 - does this ever happen? */
701 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
702 {
703 if (NEW_PROGRAM_H (n).p_vaddr
704 && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr)
705 NEW_PROGRAM_H (n).p_vaddr += new_data2_size - old_bss_size;
706
707 if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset)
708 NEW_PROGRAM_H (n).p_offset += new_data2_size;
709 }
710 #endif
711
712 /* Fix up section headers based on new .data2 section. Any section
713 * whose offset or virtual address is after the new .data2 section
714 * gets its value adjusted. .bss size becomes zero and new address
715 * is set. data2 section header gets added by copying the existing
716 * .data header and modifying the offset, address and size.
717 */
718 for (old_data_index = 1; old_data_index < (int) old_file_h->e_shnum;
719 old_data_index++)
720 if (!strcmp (old_section_names + OLD_SECTION_H (old_data_index).sh_name,
721 ".data"))
722 break;
723 if (old_data_index == old_file_h->e_shnum)
724 fatal ("Can't find .data in %s.\n", old_name, 0);
725
726 /* Walk through all section headers, insert the new data2 section right
727 before the new bss section. */
728 for (n = 1, nn = 1; n < (int) old_file_h->e_shnum; n++, nn++)
729 {
730 caddr_t src;
731 /* If it is bss section, insert the new data2 section before it. */
732 if (n == old_bss_index)
733 {
734 /* Steal the data section header for this data2 section. */
735 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index),
736 new_file_h->e_shentsize);
737
738 NEW_SECTION_H (nn).sh_addr = new_data2_addr;
739 NEW_SECTION_H (nn).sh_offset = new_data2_offset;
740 NEW_SECTION_H (nn).sh_size = new_data2_size;
741 /* Use the bss section's alignment. This will assure that the
742 new data2 section always be placed in the same spot as the old
743 bss section by any other application. */
744 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign;
745
746 /* Now copy over what we have in the memory now. */
747 memcpy (NEW_SECTION_H (nn).sh_offset + new_base,
748 (caddr_t) OLD_SECTION_H (n).sh_addr,
749 new_data2_size);
750 nn++;
751 }
752
753 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
754 old_file_h->e_shentsize);
755
756 /* The new bss section's size is zero, and its file offset and virtual
757 address should be off by NEW_DATA2_SIZE. */
758 if (n == old_bss_index)
759 {
760 /* NN should be `old_bss_index + 1' at this point. */
761 NEW_SECTION_H (nn).sh_offset += new_data2_size;
762 NEW_SECTION_H (nn).sh_addr += new_data2_size;
763 /* Let the new bss section address alignment be the same as the
764 section address alignment followed the old bss section, so
765 this section will be placed in exactly the same place. */
766 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign;
767 NEW_SECTION_H (nn).sh_size = 0;
768 }
769 else
770 {
771 /* Any section that was original placed AFTER the bss
772 section should now be off by NEW_DATA2_SIZE. */
773 #ifdef SOLARIS_POWERPC
774 /* On PPC Reference Platform running Solaris 2.5.1
775 the plt section is also of type NOBI like the bss section.
776 (not really stored) and therefore sections after the bss
777 section start at the plt offset. The plt section is always
778 the one just before the bss section.
779 It would be better to put the new data section before
780 the .plt section, or use libelf instead.
781 Erik Deumens, deumens@qtp.ufl.edu. */
782 if (NEW_SECTION_H (nn).sh_offset
783 >= OLD_SECTION_H (old_bss_index-1).sh_offset)
784 NEW_SECTION_H (nn).sh_offset += new_data2_size;
785 #else
786 if (round_up (NEW_SECTION_H (nn).sh_offset,
787 OLD_SECTION_H (old_bss_index).sh_addralign)
788 >= new_data2_offset)
789 NEW_SECTION_H (nn).sh_offset += new_data2_size;
790 #endif
791 /* Any section that was originally placed after the section
792 header table should now be off by the size of one section
793 header table entry. */
794 if (NEW_SECTION_H (nn).sh_offset > new_file_h->e_shoff)
795 NEW_SECTION_H (nn).sh_offset += new_file_h->e_shentsize;
796 }
797
798 /* If any section hdr refers to the section after the new .data
799 section, make it refer to next one because we have inserted
800 a new section in between. */
801
802 PATCH_INDEX (NEW_SECTION_H (nn).sh_link);
803 /* For symbol tables, info is a symbol table index,
804 so don't change it. */
805 if (NEW_SECTION_H (nn).sh_type != SHT_SYMTAB
806 && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM)
807 PATCH_INDEX (NEW_SECTION_H (nn).sh_info);
808
809 /* Now, start to copy the content of sections. */
810 if (NEW_SECTION_H (nn).sh_type == SHT_NULL
811 || NEW_SECTION_H (nn).sh_type == SHT_NOBITS)
812 continue;
813
814 /* Write out the sections. .data and .data1 (and data2, called
815 ".data" in the strings table) get copied from the current process
816 instead of the old file. */
817 if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data")
818 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
819 ".data1"))
820 src = (caddr_t) OLD_SECTION_H (n).sh_addr;
821 else
822 src = old_base + OLD_SECTION_H (n).sh_offset;
823
824 memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src,
825 NEW_SECTION_H (nn).sh_size);
826
827 #ifdef __alpha__
828 /* Update Alpha COFF symbol table: */
829 if (strcmp (old_section_names + OLD_SECTION_H (n).sh_name, ".mdebug")
830 == 0)
831 {
832 pHDRR symhdr = (pHDRR) (NEW_SECTION_H (nn).sh_offset + new_base);
833
834 symhdr->cbLineOffset += new_data2_size;
835 symhdr->cbDnOffset += new_data2_size;
836 symhdr->cbPdOffset += new_data2_size;
837 symhdr->cbSymOffset += new_data2_size;
838 symhdr->cbOptOffset += new_data2_size;
839 symhdr->cbAuxOffset += new_data2_size;
840 symhdr->cbSsOffset += new_data2_size;
841 symhdr->cbSsExtOffset += new_data2_size;
842 symhdr->cbFdOffset += new_data2_size;
843 symhdr->cbRfdOffset += new_data2_size;
844 symhdr->cbExtOffset += new_data2_size;
845 }
846 #endif /* __alpha__ */
847
848 /* If it is the symbol table, its st_shndx field needs to be patched. */
849 if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB
850 || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM)
851 {
852 ElfW(Shdr) *spt = &NEW_SECTION_H (nn);
853 unsigned int num = spt->sh_size / spt->sh_entsize;
854 ElfW(Sym) * sym = (ElfW(Sym) *) (NEW_SECTION_H (nn).sh_offset +
855 new_base);
856 for (; num--; sym++)
857 {
858 if ((sym->st_shndx == SHN_UNDEF)
859 || (sym->st_shndx == SHN_ABS)
860 || (sym->st_shndx == SHN_COMMON))
861 continue;
862
863 PATCH_INDEX (sym->st_shndx);
864 }
865 }
866 }
867
868 /* Update the symbol values of _edata and _end. */
869 for (n = new_file_h->e_shnum - 1; n; n--)
870 {
871 byte *symnames;
872 ElfW(Sym) *symp, *symendp;
873
874 if (NEW_SECTION_H (n).sh_type != SHT_DYNSYM
875 && NEW_SECTION_H (n).sh_type != SHT_SYMTAB)
876 continue;
877
878 symnames = ((byte *) new_base
879 + NEW_SECTION_H (NEW_SECTION_H (n).sh_link).sh_offset);
880 symp = (ElfW(Sym) *) (NEW_SECTION_H (n).sh_offset + new_base);
881 symendp = (ElfW(Sym) *) ((byte *)symp + NEW_SECTION_H (n).sh_size);
882
883 for (; symp < symendp; symp ++)
884 if (strcmp ((char *) (symnames + symp->st_name), "_end") == 0
885 || strcmp ((char *) (symnames + symp->st_name), "_edata") == 0)
886 memcpy (&symp->st_value, &new_bss_addr, sizeof (new_bss_addr));
887 }
888
889 /* This loop seeks out relocation sections for the data section, so
890 that it can undo relocations performed by the runtime linker. */
891 for (n = new_file_h->e_shnum - 1; n; n--)
892 {
893 ElfW(Shdr) section = NEW_SECTION_H (n);
894 switch (section.sh_type) {
895 default:
896 break;
897 case SHT_REL:
898 case SHT_RELA:
899 /* This code handles two different size structs, but there should
900 be no harm in that provided that r_offset is always the first
901 member. */
902 nn = section.sh_info;
903 if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".data")
904 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
905 ".data1"))
906 {
907 ElfW(Addr) offset = NEW_SECTION_H (nn).sh_addr -
908 NEW_SECTION_H (nn).sh_offset;
909 caddr_t reloc = old_base + section.sh_offset, end;
910 for (end = reloc + section.sh_size; reloc < end;
911 reloc += section.sh_entsize)
912 {
913 ElfW(Addr) addr = ((ElfW(Rel) *) reloc)->r_offset - offset;
914 #ifdef __alpha__
915 /* The Alpha ELF binutils currently have a bug that
916 sometimes results in relocs that contain all
917 zeroes. Work around this for now... */
918 if (((ElfW(Rel) *) reloc)->r_offset == 0)
919 continue;
920 #endif
921 memcpy (new_base + addr, old_base + addr, sizeof(ElfW(Addr)));
922 }
923 }
924 break;
925 }
926 }
927
928 #ifdef UNEXEC_USE_MAP_PRIVATE
929 if (lseek (new_file, 0, SEEK_SET) == -1)
930 fatal ("Can't rewind (%s): errno %d\n", new_name, errno);
931
932 if (write (new_file, new_base, new_file_size) != new_file_size)
933 fatal ("Can't write (%s): errno %d\n", new_name, errno);
934 #endif
935
936 /* Close the files and make the new file executable. */
937
938 if (close (old_file))
939 fatal ("Can't close (%s): errno %d\n", old_name, errno);
940
941 if (close (new_file))
942 fatal ("Can't close (%s): errno %d\n", new_name, errno);
943
944 if (stat (new_name, &stat_buf) == -1)
945 fatal ("Can't stat (%s): errno %d\n", new_name, errno);
946
947 n = umask (777);
948 umask (n);
949 stat_buf.st_mode |= 0111 & ~n;
950 if (chmod (new_name, stat_buf.st_mode) == -1)
951 fatal ("Can't chmod (%s): errno %d\n", new_name, errno);
952 }
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