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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, old_name, data_start, bss_start, entry_address)
37 * char *new_name, *old_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 old_name is non-NULL, the symbol table will be taken from the given file.
43 * On some machines, an existing old_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 #if !defined (__NetBSD__) && !defined (__OpenBSD__)
424 #include <elf.h>
425 #endif
426 #include <sys/mman.h>
427 #if defined (__sony_news) && defined (_SYSTYPE_SYSV)
428 #include <sys/elf_mips.h>
429 #include <sym.h>
430 #endif /* __sony_news && _SYSTYPE_SYSV */
431
432 #if defined (__alpha__) && !defined (__NetBSD__) && !defined (__OpenBSD__)
433 #include <sym.h> /* get COFF debugging symbol table declaration */
434 #endif
435
436 #ifdef __NetBSD__
437 /*
438 * NetBSD does not have normal-looking user-land ELF support.
439 */
440 # ifdef __alpha__
441 # define ELFSIZE 64
442 # else
443 # define ELFSIZE 32
444 # endif
445 # include <sys/exec_elf.h>
446
447 # define PT_LOAD Elf_pt_load
448 # define SHT_SYMTAB Elf_sht_symtab
449 # define SHT_DYNSYM Elf_sht_dynsym
450 # define SHT_NULL Elf_sht_null
451 # define SHT_NOBITS Elf_sht_nobits
452 # define SHT_REL Elf_sht_rel
453 # define SHT_RELA Elf_sht_rela
454
455 # define SHN_UNDEF Elf_eshn_undefined
456 # define SHN_ABS Elf_eshn_absolute
457 # define SHN_COMMON Elf_eshn_common
458
459 /*
460 * The magic of picking the right size types is handled by the ELFSIZE
461 * definition above.
462 */
463 # ifdef __STDC__
464 # define ElfW(type) Elf_##type
465 # else
466 # define ElfW(type) Elf_/**/type
467 # endif
468
469 # ifdef __alpha__
470 # include <sys/exec_ecoff.h>
471 # define HDRR struct ecoff_symhdr
472 # define pHDRR HDRR *
473 # endif
474 #endif /* __NetBSD__ */
475
476 #ifdef __OpenBSD__
477 # include <sys/exec_elf.h>
478 #endif
479
480 #if __GNU_LIBRARY__ - 0 >= 6
481 # include <link.h> /* get ElfW etc */
482 #endif
483
484 #ifndef ElfW
485 # ifdef __STDC__
486 # define ElfW(type) Elf32_##type
487 # else
488 # define ElfW(type) Elf32_/**/type
489 # endif
490 #endif
491
492 #ifndef emacs
493 #define fatal(a, b, c) fprintf (stderr, a, b, c), exit (1)
494 #else
495 #include <config.h>
496 extern void fatal (char *, ...);
497 #endif
498
499 #ifndef ELF_BSS_SECTION_NAME
500 #define ELF_BSS_SECTION_NAME ".bss"
501 #endif
502
503 /* Get the address of a particular section or program header entry,
504 * accounting for the size of the entries.
505 */
506 /*
507 On PPC Reference Platform running Solaris 2.5.1
508 the plt section is also of type NOBI like the bss section.
509 (not really stored) and therefore sections after the bss
510 section start at the plt offset. The plt section is always
511 the one just before the bss section.
512 Thus, we modify the test from
513 if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset)
514 to
515 if (NEW_SECTION_H (nn).sh_offset >=
516 OLD_SECTION_H (old_bss_index-1).sh_offset)
517 This is just a hack. We should put the new data section
518 before the .plt section.
519 And we should not have this routine at all but use
520 the libelf library to read the old file and create the new
521 file.
522 The changed code is minimal and depends on prep set in m/prep.h
523 Erik Deumens
524 Quantum Theory Project
525 University of Florida
526 deumens@qtp.ufl.edu
527 Apr 23, 1996
528 */
529
530 #define OLD_SECTION_H(n) \
531 (*(ElfW(Shdr) *) ((byte *) old_section_h + old_file_h->e_shentsize * (n)))
532 #define NEW_SECTION_H(n) \
533 (*(ElfW(Shdr) *) ((byte *) new_section_h + new_file_h->e_shentsize * (n)))
534 #define OLD_PROGRAM_H(n) \
535 (*(ElfW(Phdr) *) ((byte *) old_program_h + old_file_h->e_phentsize * (n)))
536 #define NEW_PROGRAM_H(n) \
537 (*(ElfW(Phdr) *) ((byte *) new_program_h + new_file_h->e_phentsize * (n)))
538
539 #define PATCH_INDEX(n) \
540 do { \
541 if ((int) (n) >= old_bss_index) \
542 (n)++; } while (0)
543 typedef unsigned char byte;
544
545 /* Round X up to a multiple of Y. */
546
547 ElfW(Addr)
548 round_up (x, y)
549 ElfW(Addr) x, y;
550 {
551 int rem = x % y;
552 if (rem == 0)
553 return x;
554 return x - rem + y;
555 }
556
557 /* ****************************************************************
558 * unexec
559 *
560 * driving logic.
561 *
562 * In ELF, this works by replacing the old .bss section with a new
563 * .data section, and inserting an empty .bss immediately afterwards.
564 *
565 */
566 void
567 unexec (new_name, old_name, data_start, bss_start, entry_address)
568 char *new_name, *old_name;
569 unsigned data_start, bss_start, entry_address;
570 {
571 int new_file, old_file, new_file_size;
572
573 /* Pointers to the base of the image of the two files. */
574 caddr_t old_base, new_base;
575
576 /* Pointers to the file, program and section headers for the old and new
577 * files.
578 */
579 ElfW(Ehdr) *old_file_h, *new_file_h;
580 ElfW(Phdr) *old_program_h, *new_program_h;
581 ElfW(Shdr) *old_section_h, *new_section_h;
582
583 /* Point to the section name table in the old file */
584 char *old_section_names;
585
586 ElfW(Addr) old_bss_addr, new_bss_addr;
587 ElfW(Word) old_bss_size, new_data2_size;
588 ElfW(Off) new_data2_offset;
589 ElfW(Addr) new_data2_addr;
590
591 int n, nn, old_bss_index, old_data_index, new_data2_index;
592 #if defined ( __sony_news) && defined (_SYSTYPE_SYSV)
593 int old_sbss_index, old_mdebug_index;
594 #endif /* __sony_news && _SYSTYPE_SYSV */
595 struct stat stat_buf;
596
597 /* Open the old file & map it into the address space. */
598
599 old_file = open (old_name, O_RDONLY);
600
601 if (old_file < 0)
602 fatal ("Can't open %s for reading: errno %d\n", old_name, errno);
603
604 if (fstat (old_file, &stat_buf) == -1)
605 fatal ("Can't fstat (%s): errno %d\n", old_name, errno);
606
607 old_base = mmap ((caddr_t) 0, stat_buf.st_size, PROT_READ, MAP_SHARED,
608 old_file, 0);
609
610 if (old_base == (caddr_t) -1)
611 fatal ("Can't mmap (%s): errno %d\n", old_name, errno);
612
613 #ifdef DEBUG
614 fprintf (stderr, "mmap (%s, %x) -> %x\n", old_name, stat_buf.st_size,
615 old_base);
616 #endif
617
618 /* Get pointers to headers & section names */
619
620 old_file_h = (ElfW(Ehdr) *) old_base;
621 old_program_h = (ElfW(Phdr) *) ((byte *) old_base + old_file_h->e_phoff);
622 old_section_h = (ElfW(Shdr) *) ((byte *) old_base + old_file_h->e_shoff);
623 old_section_names = (char *) old_base
624 + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset;
625
626 /* Find the old .bss section. Figure out parameters of the new
627 * data2 and bss sections.
628 */
629
630 for (old_bss_index = 1; old_bss_index < (int) old_file_h->e_shnum;
631 old_bss_index++)
632 {
633 #ifdef DEBUG
634 fprintf (stderr, "Looking for .bss - found %s\n",
635 old_section_names + OLD_SECTION_H (old_bss_index).sh_name);
636 #endif
637 if (!strcmp (old_section_names + OLD_SECTION_H (old_bss_index).sh_name,
638 ELF_BSS_SECTION_NAME))
639 break;
640 }
641 if (old_bss_index == old_file_h->e_shnum)
642 fatal ("Can't find .bss in %s.\n", old_name, 0);
643
644 #if defined (__sony_news) && defined (_SYSTYPE_SYSV)
645 for (old_sbss_index = 1; old_sbss_index < (int) old_file_h->e_shnum;
646 old_sbss_index++)
647 {
648 #ifdef DEBUG
649 fprintf (stderr, "Looking for .sbss - found %s\n",
650 old_section_names + OLD_SECTION_H (old_sbss_index).sh_name);
651 #endif
652 if (!strcmp (old_section_names + OLD_SECTION_H (old_sbss_index).sh_name,
653 ".sbss"))
654 break;
655 }
656 if (old_sbss_index == old_file_h->e_shnum)
657 {
658 old_bss_addr = OLD_SECTION_H(old_bss_index).sh_addr;
659 old_bss_size = OLD_SECTION_H(old_bss_index).sh_size;
660 new_data2_offset = OLD_SECTION_H(old_bss_index).sh_offset;
661 new_data2_index = old_bss_index;
662 }
663 else
664 {
665 old_bss_addr = OLD_SECTION_H(old_sbss_index).sh_addr;
666 old_bss_size = OLD_SECTION_H(old_bss_index).sh_size
667 + OLD_SECTION_H(old_sbss_index).sh_size;
668 new_data2_offset = OLD_SECTION_H(old_sbss_index).sh_offset;
669 new_data2_index = old_sbss_index;
670 }
671
672 for (old_mdebug_index = 1; old_mdebug_index < (int) old_file_h->e_shnum;
673 old_mdebug_index++)
674 {
675 #ifdef DEBUG
676 fprintf (stderr, "Looking for .mdebug - found %s\n",
677 old_section_names + OLD_SECTION_H (old_mdebug_index).sh_name);
678 #endif
679 if (!strcmp (old_section_names + OLD_SECTION_H (old_mdebug_index).sh_name,
680 ".mdebug"))
681 break;
682 }
683 if (old_mdebug_index == old_file_h->e_shnum)
684 old_mdebug_index = 0;
685 #else /* not (__sony_news && _SYSTYPE_SYSV) */
686 old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr;
687 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size;
688 #endif /* not (__sony_news && _SYSTYPE_SYSV) */
689 #if defined (emacs) || !defined (DEBUG)
690 new_bss_addr = (ElfW(Addr)) sbrk (0);
691 #else
692 new_bss_addr = old_bss_addr + old_bss_size + 0x1234;
693 #endif
694 new_data2_addr = old_bss_addr;
695 new_data2_size = new_bss_addr - old_bss_addr;
696 #if !defined (__sony_news) || !defined (_SYSTYPE_SYSV)
697 new_data2_offset = OLD_SECTION_H (old_bss_index).sh_offset;
698 #endif /* not (__sony_news && _SYSTYPE_SYSV) */
699
700 #ifdef DEBUG
701 fprintf (stderr, "old_bss_index %d\n", old_bss_index);
702 fprintf (stderr, "old_bss_addr %x\n", old_bss_addr);
703 fprintf (stderr, "old_bss_size %x\n", old_bss_size);
704 fprintf (stderr, "new_bss_addr %x\n", new_bss_addr);
705 fprintf (stderr, "new_data2_addr %x\n", new_data2_addr);
706 fprintf (stderr, "new_data2_size %x\n", new_data2_size);
707 fprintf (stderr, "new_data2_offset %x\n", new_data2_offset);
708 #endif
709
710 if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size)
711 fatal (".bss shrank when undumping???\n", 0, 0);
712
713 /* Set the output file to the right size and mmap it. Set
714 * pointers to various interesting objects. stat_buf still has
715 * old_file data.
716 */
717
718 new_file = open (new_name, O_RDWR | O_CREAT, 0666);
719 if (new_file < 0)
720 fatal ("Can't creat (%s): errno %d\n", new_name, errno);
721
722 new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_data2_size;
723
724 if (ftruncate (new_file, new_file_size))
725 fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
726
727 #ifdef UNEXEC_USE_MAP_PRIVATE
728 new_base = mmap ((caddr_t) 0, new_file_size, PROT_READ | PROT_WRITE,
729 MAP_PRIVATE, new_file, 0);
730 #else
731 new_base = mmap ((caddr_t) 0, new_file_size, PROT_READ | PROT_WRITE,
732 MAP_SHARED, new_file, 0);
733 #endif
734
735 if (new_base == (caddr_t) -1)
736 fatal ("Can't mmap (%s): errno %d\n", new_name, errno);
737
738 new_file_h = (ElfW(Ehdr) *) new_base;
739 new_program_h = (ElfW(Phdr) *) ((byte *) new_base + old_file_h->e_phoff);
740 new_section_h = (ElfW(Shdr) *)
741 ((byte *) new_base + old_file_h->e_shoff + new_data2_size);
742
743 /* Make our new file, program and section headers as copies of the
744 * originals.
745 */
746
747 memcpy (new_file_h, old_file_h, old_file_h->e_ehsize);
748 memcpy (new_program_h, old_program_h,
749 old_file_h->e_phnum * old_file_h->e_phentsize);
750
751 /* Modify the e_shstrndx if necessary. */
752 PATCH_INDEX (new_file_h->e_shstrndx);
753
754 /* Fix up file header. We'll add one section. Section header is
755 * further away now.
756 */
757
758 new_file_h->e_shoff += new_data2_size;
759 new_file_h->e_shnum += 1;
760
761 #ifdef DEBUG
762 fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff);
763 fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum);
764 fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff);
765 fprintf (stderr, "New section count %d\n", new_file_h->e_shnum);
766 #endif
767
768 /* Fix up a new program header. Extend the writable data segment so
769 * that the bss area is covered too. Find that segment by looking
770 * for a segment that ends just before the .bss area. Make sure
771 * that no segments are above the new .data2. Put a loop at the end
772 * to adjust the offset and address of any segment that is above
773 * data2, just in case we decide to allow this later.
774 */
775
776 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
777 {
778 /* Compute maximum of all requirements for alignment of section. */
779 int alignment = (NEW_PROGRAM_H (n)).p_align;
780 if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment)
781 alignment = OLD_SECTION_H (old_bss_index).sh_addralign;
782
783 #if defined (__sony_news) && defined (_SYSTYPE_SYSV)
784 if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz
785 > round_up (old_bss_addr, alignment))
786 fatal ("Program segment above .bss in %s\n", old_name, 0);
787 #else /* not (__sony_news && _SYSTYPE_SYSV) */
788 if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz > old_bss_addr)
789 fatal ("Program segment above .bss in %s\n", old_name, 0);
790 #endif /* not (__sony_news && _SYSTYPE_SYSV) */
791
792 if (NEW_PROGRAM_H (n).p_type == PT_LOAD
793 && (round_up ((NEW_PROGRAM_H (n)).p_vaddr
794 + (NEW_PROGRAM_H (n)).p_filesz,
795 alignment)
796 == round_up (old_bss_addr, alignment)))
797 break;
798 }
799 if (n < 0)
800 fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0);
801
802 NEW_PROGRAM_H (n).p_filesz += new_data2_size;
803 NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz;
804
805 #if 0 /* Maybe allow section after data2 - does this ever happen? */
806 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
807 {
808 if (NEW_PROGRAM_H (n).p_vaddr
809 && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr)
810 NEW_PROGRAM_H (n).p_vaddr += new_data2_size - old_bss_size;
811
812 if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset)
813 NEW_PROGRAM_H (n).p_offset += new_data2_size;
814 }
815 #endif
816
817 /* Fix up section headers based on new .data2 section. Any section
818 * whose offset or virtual address is after the new .data2 section
819 * gets its value adjusted. .bss size becomes zero and new address
820 * is set. data2 section header gets added by copying the existing
821 * .data header and modifying the offset, address and size.
822 */
823 for (old_data_index = 1; old_data_index < (int) old_file_h->e_shnum;
824 old_data_index++)
825 if (!strcmp (old_section_names + OLD_SECTION_H (old_data_index).sh_name,
826 ".data"))
827 break;
828 if (old_data_index == old_file_h->e_shnum)
829 fatal ("Can't find .data in %s.\n", old_name, 0);
830
831 /* Walk through all section headers, insert the new data2 section right
832 before the new bss section. */
833 for (n = 1, nn = 1; n < (int) old_file_h->e_shnum; n++, nn++)
834 {
835 caddr_t src;
836 int temp_index;
837 #if defined (__sony_news) && defined (_SYSTYPE_SYSV)
838 /* If it is (s)bss section, insert the new data2 section before it. */
839 /* new_data2_index is the index of either old_sbss or old_bss, that was
840 chosen as a section for new_data2. */
841 temp_index = new_data2_index;
842 #else /* not (__sony_news && _SYSTYPE_SYSV) */
843 /* If it is bss section, insert the new data2 section before it. */
844 temp_index = old_bss_index;
845 #endif /* not (__sony_news && _SYSTYPE_SYSV) */
846 if (n == temp_index)
847 {
848 /* Steal the data section header for this data2 section. */
849 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index),
850 new_file_h->e_shentsize);
851
852 NEW_SECTION_H (nn).sh_addr = new_data2_addr;
853 NEW_SECTION_H (nn).sh_offset = new_data2_offset;
854 NEW_SECTION_H (nn).sh_size = new_data2_size;
855 /* Use the bss section's alignment. This will assure that the
856 new data2 section always be placed in the same spot as the old
857 bss section by any other application. */
858 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign;
859
860 /* Now copy over what we have in the memory now. */
861 memcpy (NEW_SECTION_H (nn).sh_offset + new_base,
862 (caddr_t) OLD_SECTION_H (n).sh_addr,
863 new_data2_size);
864 nn++;
865 }
866
867 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
868 old_file_h->e_shentsize);
869
870 if (n == old_bss_index
871 #if defined (__sony_news) && defined (_SYSTYPE_SYSV)
872 /* The new bss and sbss section's size is zero, and its file offset
873 and virtual address should be off by NEW_DATA2_SIZE. */
874 || n == old_sbss_index
875 #endif /* __sony_news and _SYSTYPE_SYSV */
876 )
877 {
878 /* NN should be `old_bss_index + 1' at this point. */
879 NEW_SECTION_H (nn).sh_offset += new_data2_size;
880 NEW_SECTION_H (nn).sh_addr += new_data2_size;
881 /* Let the new bss section address alignment be the same as the
882 section address alignment followed the old bss section, so
883 this section will be placed in exactly the same place. */
884 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign;
885 NEW_SECTION_H (nn).sh_size = 0;
886 }
887 else
888 {
889 /* Any section that was original placed AFTER the bss
890 section should now be off by NEW_DATA2_SIZE. */
891 #ifdef SOLARIS_POWERPC
892 /* On PPC Reference Platform running Solaris 2.5.1
893 the plt section is also of type NOBI like the bss section.
894 (not really stored) and therefore sections after the bss
895 section start at the plt offset. The plt section is always
896 the one just before the bss section.
897 It would be better to put the new data section before
898 the .plt section, or use libelf instead.
899 Erik Deumens, deumens@qtp.ufl.edu. */
900 if (NEW_SECTION_H (nn).sh_offset
901 >= OLD_SECTION_H (old_bss_index-1).sh_offset)
902 NEW_SECTION_H (nn).sh_offset += new_data2_size;
903 #else
904 if (round_up (NEW_SECTION_H (nn).sh_offset,
905 OLD_SECTION_H (old_bss_index).sh_addralign)
906 >= new_data2_offset)
907 NEW_SECTION_H (nn).sh_offset += new_data2_size;
908 #endif
909 /* Any section that was originally placed after the section
910 header table should now be off by the size of one section
911 header table entry. */
912 if (NEW_SECTION_H (nn).sh_offset > new_file_h->e_shoff)
913 NEW_SECTION_H (nn).sh_offset += new_file_h->e_shentsize;
914 }
915
916 /* If any section hdr refers to the section after the new .data
917 section, make it refer to next one because we have inserted
918 a new section in between. */
919
920 PATCH_INDEX (NEW_SECTION_H (nn).sh_link);
921 /* For symbol tables, info is a symbol table index,
922 so don't change it. */
923 if (NEW_SECTION_H (nn).sh_type != SHT_SYMTAB
924 && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM)
925 PATCH_INDEX (NEW_SECTION_H (nn).sh_info);
926
927 /* Now, start to copy the content of sections. */
928 if (NEW_SECTION_H (nn).sh_type == SHT_NULL
929 || NEW_SECTION_H (nn).sh_type == SHT_NOBITS)
930 continue;
931
932 /* Write out the sections. .data and .data1 (and data2, called
933 ".data" in the strings table) get copied from the current process
934 instead of the old file. */
935 if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data")
936 #ifdef _nec_ews_svr4 /* hir, 1994.6.13 */
937 || !strcmp ((old_section_names + NEW_SECTION_H(n).sh_name),
938 ".sdata")
939 #endif
940 #if defined (__sony_news) && defined (_SYSTYPE_SYSV)
941 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
942 ".sdata")
943 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
944 ".lit4")
945 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
946 ".lit8")
947 #endif /* __sony_news && _SYSTYPE_SYSV */
948 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
949 ".data1"))
950 src = (caddr_t) OLD_SECTION_H (n).sh_addr;
951 else
952 src = old_base + OLD_SECTION_H (n).sh_offset;
953
954 memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src,
955 NEW_SECTION_H (nn).sh_size);
956
957 #ifdef __alpha__
958 /* Update Alpha COFF symbol table: */
959 if (strcmp (old_section_names + OLD_SECTION_H (n).sh_name, ".mdebug")
960 == 0)
961 {
962 pHDRR symhdr = (pHDRR) (NEW_SECTION_H (nn).sh_offset + new_base);
963
964 symhdr->cbLineOffset += new_data2_size;
965 symhdr->cbDnOffset += new_data2_size;
966 symhdr->cbPdOffset += new_data2_size;
967 symhdr->cbSymOffset += new_data2_size;
968 symhdr->cbOptOffset += new_data2_size;
969 symhdr->cbAuxOffset += new_data2_size;
970 symhdr->cbSsOffset += new_data2_size;
971 symhdr->cbSsExtOffset += new_data2_size;
972 symhdr->cbFdOffset += new_data2_size;
973 symhdr->cbRfdOffset += new_data2_size;
974 symhdr->cbExtOffset += new_data2_size;
975 }
976 #endif /* __alpha__ */
977
978 #if defined (__sony_news) && defined (_SYSTYPE_SYSV)
979 if (NEW_SECTION_H (nn).sh_type == SHT_MIPS_DEBUG && old_mdebug_index)
980 {
981 int diff = NEW_SECTION_H(nn).sh_offset
982 - OLD_SECTION_H(old_mdebug_index).sh_offset;
983 HDRR *phdr = (HDRR *)(NEW_SECTION_H (nn).sh_offset + new_base);
984
985 if (diff)
986 {
987 phdr->cbLineOffset += diff;
988 phdr->cbDnOffset += diff;
989 phdr->cbPdOffset += diff;
990 phdr->cbSymOffset += diff;
991 phdr->cbOptOffset += diff;
992 phdr->cbAuxOffset += diff;
993 phdr->cbSsOffset += diff;
994 phdr->cbSsExtOffset += diff;
995 phdr->cbFdOffset += diff;
996 phdr->cbRfdOffset += diff;
997 phdr->cbExtOffset += diff;
998 }
999 }
1000 #endif /* __sony_news && _SYSTYPE_SYSV */
1001 /* If it is the symbol table, its st_shndx field needs to be patched. */
1002 if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB
1003 || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM)
1004 {
1005 ElfW(Shdr) *spt = &NEW_SECTION_H (nn);
1006 unsigned int num = spt->sh_size / spt->sh_entsize;
1007 ElfW(Sym) * sym = (ElfW(Sym) *) (NEW_SECTION_H (nn).sh_offset +
1008 new_base);
1009 for (; num--; sym++)
1010 {
1011 if ((sym->st_shndx == SHN_UNDEF)
1012 || (sym->st_shndx == SHN_ABS)
1013 || (sym->st_shndx == SHN_COMMON))
1014 continue;
1015
1016 PATCH_INDEX (sym->st_shndx);
1017 }
1018 }
1019 }
1020
1021 /* Update the symbol values of _edata and _end. */
1022 for (n = new_file_h->e_shnum - 1; n; n--)
1023 {
1024 byte *symnames;
1025 ElfW(Sym) *symp, *symendp;
1026
1027 if (NEW_SECTION_H (n).sh_type != SHT_DYNSYM
1028 && NEW_SECTION_H (n).sh_type != SHT_SYMTAB)
1029 continue;
1030
1031 symnames = ((byte *) new_base
1032 + NEW_SECTION_H (NEW_SECTION_H (n).sh_link).sh_offset);
1033 symp = (ElfW(Sym) *) (NEW_SECTION_H (n).sh_offset + new_base);
1034 symendp = (ElfW(Sym) *) ((byte *)symp + NEW_SECTION_H (n).sh_size);
1035
1036 for (; symp < symendp; symp ++)
1037 if (strcmp ((char *) (symnames + symp->st_name), "_end") == 0
1038 || strcmp ((char *) (symnames + symp->st_name), "_edata") == 0)
1039 memcpy (&symp->st_value, &new_bss_addr, sizeof (new_bss_addr));
1040 }
1041
1042 /* This loop seeks out relocation sections for the data section, so
1043 that it can undo relocations performed by the runtime linker. */
1044 for (n = new_file_h->e_shnum - 1; n; n--)
1045 {
1046 ElfW(Shdr) section = NEW_SECTION_H (n);
1047 switch (section.sh_type) {
1048 default:
1049 break;
1050 case SHT_REL:
1051 case SHT_RELA:
1052 /* This code handles two different size structs, but there should
1053 be no harm in that provided that r_offset is always the first
1054 member. */
1055 nn = section.sh_info;
1056 if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".data")
1057 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1058 ".data1"))
1059 {
1060 ElfW(Addr) offset = NEW_SECTION_H (nn).sh_addr -
1061 NEW_SECTION_H (nn).sh_offset;
1062 caddr_t reloc = old_base + section.sh_offset, end;
1063 for (end = reloc + section.sh_size; reloc < end;
1064 reloc += section.sh_entsize)
1065 {
1066 ElfW(Addr) addr = ((ElfW(Rel) *) reloc)->r_offset - offset;
1067 #ifdef __alpha__
1068 /* The Alpha ELF binutils currently have a bug that
1069 sometimes results in relocs that contain all
1070 zeroes. Work around this for now... */
1071 if (((ElfW(Rel) *) reloc)->r_offset == 0)
1072 continue;
1073 #endif
1074 memcpy (new_base + addr, old_base + addr, sizeof(ElfW(Addr)));
1075 }
1076 }
1077 break;
1078 }
1079 }
1080
1081 #ifdef UNEXEC_USE_MAP_PRIVATE
1082 if (lseek (new_file, 0, SEEK_SET) == -1)
1083 fatal ("Can't rewind (%s): errno %d\n", new_name, errno);
1084
1085 if (write (new_file, new_base, new_file_size) != new_file_size)
1086 fatal ("Can't write (%s): errno %d\n", new_name, errno);
1087 #endif
1088
1089 /* Close the files and make the new file executable. */
1090
1091 if (close (old_file))
1092 fatal ("Can't close (%s): errno %d\n", old_name, errno);
1093
1094 if (close (new_file))
1095 fatal ("Can't close (%s): errno %d\n", new_name, errno);
1096
1097 if (stat (new_name, &stat_buf) == -1)
1098 fatal ("Can't stat (%s): errno %d\n", new_name, errno);
1099
1100 n = umask (777);
1101 umask (n);
1102 stat_buf.st_mode |= 0111 & ~n;
1103 if (chmod (new_name, stat_buf.st_mode) == -1)
1104 fatal ("Can't chmod (%s): errno %d\n", new_name, errno);
1105 }