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[__linux__ && __alpha__] (HAS_SBSS_SECTION): Define.
[bpt/emacs.git] / src / unexelf.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, 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 #define HAS_SBSS_SECTION
431 #endif /* __sony_news && _SYSTYPE_SYSV */
432
433 #if defined (__NetBSD__) && defined (__powerpc__)
434 #define HAS_SBSS_SECTION
435 #endif
436
437 #if defined (__linux__) && defined (__alpha__)
438 #define HAS_SBSS_SECTION
439 #endif
440
441 #if defined (__alpha__) && !defined (__NetBSD__) && !defined (__OpenBSD__)
442 /* Declare COFF debugging symbol table. This used to be in
443 /usr/include/sym.h, but this file is no longer included in Red Hat
444 5.0 and presumably in any other glibc 2.x based distribution. */
445 typedef struct {
446 short magic;
447 short vstamp;
448 int ilineMax;
449 int idnMax;
450 int ipdMax;
451 int isymMax;
452 int ioptMax;
453 int iauxMax;
454 int issMax;
455 int issExtMax;
456 int ifdMax;
457 int crfd;
458 int iextMax;
459 long cbLine;
460 long cbLineOffset;
461 long cbDnOffset;
462 long cbPdOffset;
463 long cbSymOffset;
464 long cbOptOffset;
465 long cbAuxOffset;
466 long cbSsOffset;
467 long cbSsExtOffset;
468 long cbFdOffset;
469 long cbRfdOffset;
470 long cbExtOffset;
471 } HDRR, *pHDRR;
472 #define cbHDRR sizeof(HDRR)
473 #define hdrNil ((pHDRR)0)
474 #endif
475
476 #ifdef __NetBSD__
477 /*
478 * NetBSD does not have normal-looking user-land ELF support.
479 */
480 # ifdef __alpha__
481 # define ELFSIZE 64
482 # else
483 # define ELFSIZE 32
484 # endif
485 # include <sys/exec_elf.h>
486
487 # define PT_LOAD Elf_pt_load
488 # define SHT_SYMTAB Elf_sht_symtab
489 # define SHT_DYNSYM Elf_sht_dynsym
490 # define SHT_NULL Elf_sht_null
491 # define SHT_NOBITS Elf_sht_nobits
492 # define SHT_REL Elf_sht_rel
493 # define SHT_RELA Elf_sht_rela
494
495 # define SHN_UNDEF Elf_eshn_undefined
496 # define SHN_ABS Elf_eshn_absolute
497 # define SHN_COMMON Elf_eshn_common
498
499 /*
500 * The magic of picking the right size types is handled by the ELFSIZE
501 * definition above.
502 */
503 # ifdef __STDC__
504 # define ElfW(type) Elf_##type
505 # else
506 # define ElfW(type) Elf_/**/type
507 # endif
508
509 # ifdef __alpha__
510 # include <sys/exec_ecoff.h>
511 # define HDRR struct ecoff_symhdr
512 # define pHDRR HDRR *
513 # endif
514 #endif /* __NetBSD__ */
515
516 #ifdef __OpenBSD__
517 # include <sys/exec_elf.h>
518 #endif
519
520 #if __GNU_LIBRARY__ - 0 >= 6
521 # include <link.h> /* get ElfW etc */
522 #endif
523
524 #ifndef ElfW
525 # ifdef __STDC__
526 # define ElfW(type) Elf32_##type
527 # else
528 # define ElfW(type) Elf32_/**/type
529 # endif
530 #endif
531
532 #ifndef emacs
533 #define fatal(a, b, c) fprintf (stderr, a, b, c), exit (1)
534 #else
535 #include <config.h>
536 extern void fatal (char *, ...);
537 #endif
538
539 #ifndef ELF_BSS_SECTION_NAME
540 #define ELF_BSS_SECTION_NAME ".bss"
541 #endif
542
543 /* Get the address of a particular section or program header entry,
544 * accounting for the size of the entries.
545 */
546 /*
547 On PPC Reference Platform running Solaris 2.5.1
548 the plt section is also of type NOBI like the bss section.
549 (not really stored) and therefore sections after the bss
550 section start at the plt offset. The plt section is always
551 the one just before the bss section.
552 Thus, we modify the test from
553 if (NEW_SECTION_H (nn).sh_offset >= new_data2_offset)
554 to
555 if (NEW_SECTION_H (nn).sh_offset >=
556 OLD_SECTION_H (old_bss_index-1).sh_offset)
557 This is just a hack. We should put the new data section
558 before the .plt section.
559 And we should not have this routine at all but use
560 the libelf library to read the old file and create the new
561 file.
562 The changed code is minimal and depends on prep set in m/prep.h
563 Erik Deumens
564 Quantum Theory Project
565 University of Florida
566 deumens@qtp.ufl.edu
567 Apr 23, 1996
568 */
569
570 #define OLD_SECTION_H(n) \
571 (*(ElfW(Shdr) *) ((byte *) old_section_h + old_file_h->e_shentsize * (n)))
572 #define NEW_SECTION_H(n) \
573 (*(ElfW(Shdr) *) ((byte *) new_section_h + new_file_h->e_shentsize * (n)))
574 #define OLD_PROGRAM_H(n) \
575 (*(ElfW(Phdr) *) ((byte *) old_program_h + old_file_h->e_phentsize * (n)))
576 #define NEW_PROGRAM_H(n) \
577 (*(ElfW(Phdr) *) ((byte *) new_program_h + new_file_h->e_phentsize * (n)))
578
579 #define PATCH_INDEX(n) \
580 do { \
581 if ((int) (n) >= old_bss_index) \
582 (n)++; } while (0)
583 typedef unsigned char byte;
584
585 /* Round X up to a multiple of Y. */
586
587 ElfW(Addr)
588 round_up (x, y)
589 ElfW(Addr) x, y;
590 {
591 int rem = x % y;
592 if (rem == 0)
593 return x;
594 return x - rem + y;
595 }
596
597 /* ****************************************************************
598 * unexec
599 *
600 * driving logic.
601 *
602 * In ELF, this works by replacing the old .bss section with a new
603 * .data section, and inserting an empty .bss immediately afterwards.
604 *
605 */
606 void
607 unexec (new_name, old_name, data_start, bss_start, entry_address)
608 char *new_name, *old_name;
609 unsigned data_start, bss_start, entry_address;
610 {
611 int new_file, old_file, new_file_size;
612
613 /* Pointers to the base of the image of the two files. */
614 caddr_t old_base, new_base;
615
616 /* Pointers to the file, program and section headers for the old and new
617 * files.
618 */
619 ElfW(Ehdr) *old_file_h, *new_file_h;
620 ElfW(Phdr) *old_program_h, *new_program_h;
621 ElfW(Shdr) *old_section_h, *new_section_h;
622
623 /* Point to the section name table in the old file */
624 char *old_section_names;
625
626 ElfW(Addr) old_bss_addr, new_bss_addr;
627 ElfW(Word) old_bss_size, new_data2_size;
628 ElfW(Off) new_data2_offset;
629 ElfW(Addr) new_data2_addr;
630
631 int n, nn, old_bss_index, old_data_index, new_data2_index;
632 #if defined (HAS_SBSS_SECTION)
633 int old_sbss_index, old_mdebug_index;
634 #endif /* HAS_SBSS_SECTION */
635 struct stat stat_buf;
636
637 /* Open the old file & map it into the address space. */
638
639 old_file = open (old_name, O_RDONLY);
640
641 if (old_file < 0)
642 fatal ("Can't open %s for reading: errno %d\n", old_name, errno);
643
644 if (fstat (old_file, &stat_buf) == -1)
645 fatal ("Can't fstat (%s): errno %d\n", old_name, errno);
646
647 old_base = mmap ((caddr_t) 0, stat_buf.st_size, PROT_READ, MAP_SHARED,
648 old_file, 0);
649
650 if (old_base == (caddr_t) -1)
651 fatal ("Can't mmap (%s): errno %d\n", old_name, errno);
652
653 #ifdef DEBUG
654 fprintf (stderr, "mmap (%s, %x) -> %x\n", old_name, stat_buf.st_size,
655 old_base);
656 #endif
657
658 /* Get pointers to headers & section names */
659
660 old_file_h = (ElfW(Ehdr) *) old_base;
661 old_program_h = (ElfW(Phdr) *) ((byte *) old_base + old_file_h->e_phoff);
662 old_section_h = (ElfW(Shdr) *) ((byte *) old_base + old_file_h->e_shoff);
663 old_section_names = (char *) old_base
664 + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset;
665
666 /* Find the old .bss section. Figure out parameters of the new
667 * data2 and bss sections.
668 */
669
670 for (old_bss_index = 1; old_bss_index < (int) old_file_h->e_shnum;
671 old_bss_index++)
672 {
673 #ifdef DEBUG
674 fprintf (stderr, "Looking for .bss - found %s\n",
675 old_section_names + OLD_SECTION_H (old_bss_index).sh_name);
676 #endif
677 if (!strcmp (old_section_names + OLD_SECTION_H (old_bss_index).sh_name,
678 ELF_BSS_SECTION_NAME))
679 break;
680 }
681 if (old_bss_index == old_file_h->e_shnum)
682 fatal ("Can't find .bss in %s.\n", old_name, 0);
683
684 #if defined (HAS_SBSS_SECTION)
685 for (old_sbss_index = 1; old_sbss_index < (int) old_file_h->e_shnum;
686 old_sbss_index++)
687 {
688 #ifdef DEBUG
689 fprintf (stderr, "Looking for .sbss - found %s\n",
690 old_section_names + OLD_SECTION_H (old_sbss_index).sh_name);
691 #endif
692 if (!strcmp (old_section_names + OLD_SECTION_H (old_sbss_index).sh_name,
693 ".sbss"))
694 break;
695 }
696 if (old_sbss_index == old_file_h->e_shnum)
697 {
698 old_bss_addr = OLD_SECTION_H(old_bss_index).sh_addr;
699 old_bss_size = OLD_SECTION_H(old_bss_index).sh_size;
700 new_data2_offset = OLD_SECTION_H(old_bss_index).sh_offset;
701 new_data2_index = old_bss_index;
702 }
703 else
704 {
705 old_bss_addr = OLD_SECTION_H(old_sbss_index).sh_addr;
706 old_bss_size = OLD_SECTION_H(old_bss_index).sh_size
707 + OLD_SECTION_H(old_sbss_index).sh_size;
708 new_data2_offset = OLD_SECTION_H(old_sbss_index).sh_offset;
709 new_data2_index = old_sbss_index;
710 }
711
712 for (old_mdebug_index = 1; old_mdebug_index < (int) old_file_h->e_shnum;
713 old_mdebug_index++)
714 {
715 #ifdef DEBUG
716 fprintf (stderr, "Looking for .mdebug - found %s\n",
717 old_section_names + OLD_SECTION_H (old_mdebug_index).sh_name);
718 #endif
719 if (!strcmp (old_section_names + OLD_SECTION_H (old_mdebug_index).sh_name,
720 ".mdebug"))
721 break;
722 }
723 if (old_mdebug_index == old_file_h->e_shnum)
724 old_mdebug_index = 0;
725 #else /* not HAS_SBSS_SECTION */
726 old_bss_addr = OLD_SECTION_H (old_bss_index).sh_addr;
727 old_bss_size = OLD_SECTION_H (old_bss_index).sh_size;
728 #endif /* not HAS_SBSS_SECTION */
729 #if defined (emacs) || !defined (DEBUG)
730 new_bss_addr = (ElfW(Addr)) sbrk (0);
731 #else
732 new_bss_addr = old_bss_addr + old_bss_size + 0x1234;
733 #endif
734 new_data2_addr = old_bss_addr;
735 new_data2_size = new_bss_addr - old_bss_addr;
736 #if !defined (HAS_SBSS_SECTION)
737 new_data2_offset = OLD_SECTION_H (old_bss_index).sh_offset;
738 #endif /* not HAS_SBSS_SECTION */
739
740 #ifdef DEBUG
741 fprintf (stderr, "old_bss_index %d\n", old_bss_index);
742 fprintf (stderr, "old_bss_addr %x\n", old_bss_addr);
743 fprintf (stderr, "old_bss_size %x\n", old_bss_size);
744 fprintf (stderr, "new_bss_addr %x\n", new_bss_addr);
745 fprintf (stderr, "new_data2_addr %x\n", new_data2_addr);
746 fprintf (stderr, "new_data2_size %x\n", new_data2_size);
747 fprintf (stderr, "new_data2_offset %x\n", new_data2_offset);
748 #endif
749
750 if ((unsigned) new_bss_addr < (unsigned) old_bss_addr + old_bss_size)
751 fatal (".bss shrank when undumping???\n", 0, 0);
752
753 /* Set the output file to the right size and mmap it. Set
754 * pointers to various interesting objects. stat_buf still has
755 * old_file data.
756 */
757
758 new_file = open (new_name, O_RDWR | O_CREAT, 0666);
759 if (new_file < 0)
760 fatal ("Can't creat (%s): errno %d\n", new_name, errno);
761
762 new_file_size = stat_buf.st_size + old_file_h->e_shentsize + new_data2_size;
763
764 if (ftruncate (new_file, new_file_size))
765 fatal ("Can't ftruncate (%s): errno %d\n", new_name, errno);
766
767 #ifdef UNEXEC_USE_MAP_PRIVATE
768 new_base = mmap ((caddr_t) 0, new_file_size, PROT_READ | PROT_WRITE,
769 MAP_PRIVATE, new_file, 0);
770 #else
771 new_base = mmap ((caddr_t) 0, new_file_size, PROT_READ | PROT_WRITE,
772 MAP_SHARED, new_file, 0);
773 #endif
774
775 if (new_base == (caddr_t) -1)
776 fatal ("Can't mmap (%s): errno %d\n", new_name, errno);
777
778 new_file_h = (ElfW(Ehdr) *) new_base;
779 new_program_h = (ElfW(Phdr) *) ((byte *) new_base + old_file_h->e_phoff);
780 new_section_h = (ElfW(Shdr) *)
781 ((byte *) new_base + old_file_h->e_shoff + new_data2_size);
782
783 /* Make our new file, program and section headers as copies of the
784 * originals.
785 */
786
787 memcpy (new_file_h, old_file_h, old_file_h->e_ehsize);
788 memcpy (new_program_h, old_program_h,
789 old_file_h->e_phnum * old_file_h->e_phentsize);
790
791 /* Modify the e_shstrndx if necessary. */
792 PATCH_INDEX (new_file_h->e_shstrndx);
793
794 /* Fix up file header. We'll add one section. Section header is
795 * further away now.
796 */
797
798 new_file_h->e_shoff += new_data2_size;
799 new_file_h->e_shnum += 1;
800
801 #ifdef DEBUG
802 fprintf (stderr, "Old section offset %x\n", old_file_h->e_shoff);
803 fprintf (stderr, "Old section count %d\n", old_file_h->e_shnum);
804 fprintf (stderr, "New section offset %x\n", new_file_h->e_shoff);
805 fprintf (stderr, "New section count %d\n", new_file_h->e_shnum);
806 #endif
807
808 /* Fix up a new program header. Extend the writable data segment so
809 * that the bss area is covered too. Find that segment by looking
810 * for a segment that ends just before the .bss area. Make sure
811 * that no segments are above the new .data2. Put a loop at the end
812 * to adjust the offset and address of any segment that is above
813 * data2, just in case we decide to allow this later.
814 */
815
816 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
817 {
818 /* Compute maximum of all requirements for alignment of section. */
819 int alignment = (NEW_PROGRAM_H (n)).p_align;
820 if ((OLD_SECTION_H (old_bss_index)).sh_addralign > alignment)
821 alignment = OLD_SECTION_H (old_bss_index).sh_addralign;
822
823 #if defined (HAS_SBSS_SECTION)
824 if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz
825 > round_up (old_bss_addr, alignment))
826 fatal ("Program segment above .bss in %s\n", old_name, 0);
827 #else /* not HAS_SBSS_SECTION */
828 if (NEW_PROGRAM_H (n).p_vaddr + NEW_PROGRAM_H (n).p_filesz > old_bss_addr)
829 fatal ("Program segment above .bss in %s\n", old_name, 0);
830 #endif /* not HAS_SBSS_SECTION */
831
832 if (NEW_PROGRAM_H (n).p_type == PT_LOAD
833 && (round_up ((NEW_PROGRAM_H (n)).p_vaddr
834 + (NEW_PROGRAM_H (n)).p_filesz,
835 alignment)
836 == round_up (old_bss_addr, alignment)))
837 break;
838 }
839 if (n < 0)
840 fatal ("Couldn't find segment next to .bss in %s\n", old_name, 0);
841
842 /* Make sure that the size includes any padding before the old .bss
843 section. */
844 NEW_PROGRAM_H (n).p_filesz = new_bss_addr - NEW_PROGRAM_H (n).p_vaddr;
845 NEW_PROGRAM_H (n).p_memsz = NEW_PROGRAM_H (n).p_filesz;
846
847 #if 0 /* Maybe allow section after data2 - does this ever happen? */
848 for (n = new_file_h->e_phnum - 1; n >= 0; n--)
849 {
850 if (NEW_PROGRAM_H (n).p_vaddr
851 && NEW_PROGRAM_H (n).p_vaddr >= new_data2_addr)
852 NEW_PROGRAM_H (n).p_vaddr += new_data2_size - old_bss_size;
853
854 if (NEW_PROGRAM_H (n).p_offset >= new_data2_offset)
855 NEW_PROGRAM_H (n).p_offset += new_data2_size;
856 }
857 #endif
858
859 /* Fix up section headers based on new .data2 section. Any section
860 * whose offset or virtual address is after the new .data2 section
861 * gets its value adjusted. .bss size becomes zero and new address
862 * is set. data2 section header gets added by copying the existing
863 * .data header and modifying the offset, address and size.
864 */
865 for (old_data_index = 1; old_data_index < (int) old_file_h->e_shnum;
866 old_data_index++)
867 if (!strcmp (old_section_names + OLD_SECTION_H (old_data_index).sh_name,
868 ".data"))
869 break;
870 if (old_data_index == old_file_h->e_shnum)
871 fatal ("Can't find .data in %s.\n", old_name, 0);
872
873 /* Walk through all section headers, insert the new data2 section right
874 before the new bss section. */
875 for (n = 1, nn = 1; n < (int) old_file_h->e_shnum; n++, nn++)
876 {
877 caddr_t src;
878 int temp_index;
879 #if defined (HAS_SBSS_SECTION)
880 /* If it is (s)bss section, insert the new data2 section before it. */
881 /* new_data2_index is the index of either old_sbss or old_bss, that was
882 chosen as a section for new_data2. */
883 temp_index = new_data2_index;
884 #else /* not HAS_SBSS_SECTION */
885 /* If it is bss section, insert the new data2 section before it. */
886 temp_index = old_bss_index;
887 #endif /* not HAS_SBSS_SECTION */
888 if (n == temp_index)
889 {
890 /* Steal the data section header for this data2 section. */
891 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (old_data_index),
892 new_file_h->e_shentsize);
893
894 NEW_SECTION_H (nn).sh_addr = new_data2_addr;
895 NEW_SECTION_H (nn).sh_offset = new_data2_offset;
896 NEW_SECTION_H (nn).sh_size = new_data2_size;
897 /* Use the bss section's alignment. This will assure that the
898 new data2 section always be placed in the same spot as the old
899 bss section by any other application. */
900 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (n).sh_addralign;
901
902 /* Now copy over what we have in the memory now. */
903 memcpy (NEW_SECTION_H (nn).sh_offset + new_base,
904 (caddr_t) OLD_SECTION_H (n).sh_addr,
905 new_data2_size);
906 nn++;
907 }
908
909 memcpy (&NEW_SECTION_H (nn), &OLD_SECTION_H (n),
910 old_file_h->e_shentsize);
911
912 if (n == old_bss_index
913 #if defined (HAS_SBSS_SECTION)
914 /* The new bss and sbss section's size is zero, and its file offset
915 and virtual address should be off by NEW_DATA2_SIZE. */
916 || n == old_sbss_index
917 #endif /* HAS_SBSS_SECTION */
918 )
919 {
920 /* NN should be `old_bss_index + 1' at this point. */
921 NEW_SECTION_H (nn).sh_offset += new_data2_size;
922 NEW_SECTION_H (nn).sh_addr += new_data2_size;
923 /* Let the new bss section address alignment be the same as the
924 section address alignment followed the old bss section, so
925 this section will be placed in exactly the same place. */
926 NEW_SECTION_H (nn).sh_addralign = OLD_SECTION_H (nn).sh_addralign;
927 NEW_SECTION_H (nn).sh_size = 0;
928 }
929 else
930 {
931 /* Any section that was original placed AFTER the bss
932 section should now be off by NEW_DATA2_SIZE. */
933 #ifdef SOLARIS_POWERPC
934 /* On PPC Reference Platform running Solaris 2.5.1
935 the plt section is also of type NOBI like the bss section.
936 (not really stored) and therefore sections after the bss
937 section start at the plt offset. The plt section is always
938 the one just before the bss section.
939 It would be better to put the new data section before
940 the .plt section, or use libelf instead.
941 Erik Deumens, deumens@qtp.ufl.edu. */
942 if (NEW_SECTION_H (nn).sh_offset
943 >= OLD_SECTION_H (old_bss_index-1).sh_offset)
944 NEW_SECTION_H (nn).sh_offset += new_data2_size;
945 #else
946 if (round_up (NEW_SECTION_H (nn).sh_offset,
947 OLD_SECTION_H (old_bss_index).sh_addralign)
948 >= new_data2_offset)
949 NEW_SECTION_H (nn).sh_offset += new_data2_size;
950 #endif
951 /* Any section that was originally placed after the section
952 header table should now be off by the size of one section
953 header table entry. */
954 if (NEW_SECTION_H (nn).sh_offset > new_file_h->e_shoff)
955 NEW_SECTION_H (nn).sh_offset += new_file_h->e_shentsize;
956 }
957
958 /* If any section hdr refers to the section after the new .data
959 section, make it refer to next one because we have inserted
960 a new section in between. */
961
962 PATCH_INDEX (NEW_SECTION_H (nn).sh_link);
963 /* For symbol tables, info is a symbol table index,
964 so don't change it. */
965 if (NEW_SECTION_H (nn).sh_type != SHT_SYMTAB
966 && NEW_SECTION_H (nn).sh_type != SHT_DYNSYM)
967 PATCH_INDEX (NEW_SECTION_H (nn).sh_info);
968
969 /* Now, start to copy the content of sections. */
970 if (NEW_SECTION_H (nn).sh_type == SHT_NULL
971 || NEW_SECTION_H (nn).sh_type == SHT_NOBITS)
972 continue;
973
974 /* Write out the sections. .data and .data1 (and data2, called
975 ".data" in the strings table) get copied from the current process
976 instead of the old file. */
977 if (!strcmp (old_section_names + NEW_SECTION_H (n).sh_name, ".data")
978 #ifdef _nec_ews_svr4 /* hir, 1994.6.13 */
979 || !strcmp ((old_section_names + NEW_SECTION_H(n).sh_name),
980 ".sdata")
981 #endif
982 #if defined (HAS_SBSS_SECTION)
983 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
984 ".sdata")
985 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
986 ".lit4")
987 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
988 ".lit8")
989 #endif /* HAS_SBSS_SECTION */
990 || !strcmp ((old_section_names + NEW_SECTION_H (n).sh_name),
991 ".data1"))
992 src = (caddr_t) OLD_SECTION_H (n).sh_addr;
993 else
994 src = old_base + OLD_SECTION_H (n).sh_offset;
995
996 memcpy (NEW_SECTION_H (nn).sh_offset + new_base, src,
997 NEW_SECTION_H (nn).sh_size);
998
999 #ifdef __alpha__
1000 /* Update Alpha COFF symbol table: */
1001 if (strcmp (old_section_names + OLD_SECTION_H (n).sh_name, ".mdebug")
1002 == 0)
1003 {
1004 pHDRR symhdr = (pHDRR) (NEW_SECTION_H (nn).sh_offset + new_base);
1005
1006 symhdr->cbLineOffset += new_data2_size;
1007 symhdr->cbDnOffset += new_data2_size;
1008 symhdr->cbPdOffset += new_data2_size;
1009 symhdr->cbSymOffset += new_data2_size;
1010 symhdr->cbOptOffset += new_data2_size;
1011 symhdr->cbAuxOffset += new_data2_size;
1012 symhdr->cbSsOffset += new_data2_size;
1013 symhdr->cbSsExtOffset += new_data2_size;
1014 symhdr->cbFdOffset += new_data2_size;
1015 symhdr->cbRfdOffset += new_data2_size;
1016 symhdr->cbExtOffset += new_data2_size;
1017 }
1018 #endif /* __alpha__ */
1019
1020 #if defined (__sony_news) && defined (_SYSTYPE_SYSV)
1021 if (NEW_SECTION_H (nn).sh_type == SHT_MIPS_DEBUG && old_mdebug_index)
1022 {
1023 int diff = NEW_SECTION_H(nn).sh_offset
1024 - OLD_SECTION_H(old_mdebug_index).sh_offset;
1025 HDRR *phdr = (HDRR *)(NEW_SECTION_H (nn).sh_offset + new_base);
1026
1027 if (diff)
1028 {
1029 phdr->cbLineOffset += diff;
1030 phdr->cbDnOffset += diff;
1031 phdr->cbPdOffset += diff;
1032 phdr->cbSymOffset += diff;
1033 phdr->cbOptOffset += diff;
1034 phdr->cbAuxOffset += diff;
1035 phdr->cbSsOffset += diff;
1036 phdr->cbSsExtOffset += diff;
1037 phdr->cbFdOffset += diff;
1038 phdr->cbRfdOffset += diff;
1039 phdr->cbExtOffset += diff;
1040 }
1041 }
1042 #endif /* __sony_news && _SYSTYPE_SYSV */
1043 /* If it is the symbol table, its st_shndx field needs to be patched. */
1044 if (NEW_SECTION_H (nn).sh_type == SHT_SYMTAB
1045 || NEW_SECTION_H (nn).sh_type == SHT_DYNSYM)
1046 {
1047 ElfW(Shdr) *spt = &NEW_SECTION_H (nn);
1048 unsigned int num = spt->sh_size / spt->sh_entsize;
1049 ElfW(Sym) * sym = (ElfW(Sym) *) (NEW_SECTION_H (nn).sh_offset +
1050 new_base);
1051 for (; num--; sym++)
1052 {
1053 if ((sym->st_shndx == SHN_UNDEF)
1054 || (sym->st_shndx == SHN_ABS)
1055 || (sym->st_shndx == SHN_COMMON))
1056 continue;
1057
1058 PATCH_INDEX (sym->st_shndx);
1059 }
1060 }
1061 }
1062
1063 /* Update the symbol values of _edata and _end. */
1064 for (n = new_file_h->e_shnum - 1; n; n--)
1065 {
1066 byte *symnames;
1067 ElfW(Sym) *symp, *symendp;
1068
1069 if (NEW_SECTION_H (n).sh_type != SHT_DYNSYM
1070 && NEW_SECTION_H (n).sh_type != SHT_SYMTAB)
1071 continue;
1072
1073 symnames = ((byte *) new_base
1074 + NEW_SECTION_H (NEW_SECTION_H (n).sh_link).sh_offset);
1075 symp = (ElfW(Sym) *) (NEW_SECTION_H (n).sh_offset + new_base);
1076 symendp = (ElfW(Sym) *) ((byte *)symp + NEW_SECTION_H (n).sh_size);
1077
1078 for (; symp < symendp; symp ++)
1079 if (strcmp ((char *) (symnames + symp->st_name), "_end") == 0
1080 || strcmp ((char *) (symnames + symp->st_name), "end") == 0
1081 || strcmp ((char *) (symnames + symp->st_name), "_edata") == 0
1082 || strcmp ((char *) (symnames + symp->st_name), "edata") == 0)
1083 memcpy (&symp->st_value, &new_bss_addr, sizeof (new_bss_addr));
1084 }
1085
1086 /* This loop seeks out relocation sections for the data section, so
1087 that it can undo relocations performed by the runtime linker. */
1088 for (n = new_file_h->e_shnum - 1; n; n--)
1089 {
1090 ElfW(Shdr) section = NEW_SECTION_H (n);
1091 switch (section.sh_type) {
1092 default:
1093 break;
1094 case SHT_REL:
1095 case SHT_RELA:
1096 /* This code handles two different size structs, but there should
1097 be no harm in that provided that r_offset is always the first
1098 member. */
1099 nn = section.sh_info;
1100 if (!strcmp (old_section_names + NEW_SECTION_H (nn).sh_name, ".data")
1101 || !strcmp ((old_section_names + NEW_SECTION_H (nn).sh_name),
1102 ".data1"))
1103 {
1104 ElfW(Addr) offset = NEW_SECTION_H (nn).sh_addr -
1105 NEW_SECTION_H (nn).sh_offset;
1106 caddr_t reloc = old_base + section.sh_offset, end;
1107 for (end = reloc + section.sh_size; reloc < end;
1108 reloc += section.sh_entsize)
1109 {
1110 ElfW(Addr) addr = ((ElfW(Rel) *) reloc)->r_offset - offset;
1111 #ifdef __alpha__
1112 /* The Alpha ELF binutils currently have a bug that
1113 sometimes results in relocs that contain all
1114 zeroes. Work around this for now... */
1115 if (((ElfW(Rel) *) reloc)->r_offset == 0)
1116 continue;
1117 #endif
1118 memcpy (new_base + addr, old_base + addr, sizeof(ElfW(Addr)));
1119 }
1120 }
1121 break;
1122 }
1123 }
1124
1125 #ifdef UNEXEC_USE_MAP_PRIVATE
1126 if (lseek (new_file, 0, SEEK_SET) == -1)
1127 fatal ("Can't rewind (%s): errno %d\n", new_name, errno);
1128
1129 if (write (new_file, new_base, new_file_size) != new_file_size)
1130 fatal ("Can't write (%s): errno %d\n", new_name, errno);
1131 #endif
1132
1133 /* Close the files and make the new file executable. */
1134
1135 if (close (old_file))
1136 fatal ("Can't close (%s): errno %d\n", old_name, errno);
1137
1138 if (close (new_file))
1139 fatal ("Can't close (%s): errno %d\n", new_name, errno);
1140
1141 if (stat (new_name, &stat_buf) == -1)
1142 fatal ("Can't stat (%s): errno %d\n", new_name, errno);
1143
1144 n = umask (777);
1145 umask (n);
1146 stat_buf.st_mode |= 0111 & ~n;
1147 if (chmod (new_name, stat_buf.st_mode) == -1)
1148 fatal ("Can't chmod (%s): errno %d\n", new_name, errno);
1149 }
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